1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ C H 8 -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2021, Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING3. If not, go to -- 19-- http://www.gnu.org/licenses for a complete copy of the license. -- 20-- -- 21-- GNAT was originally developed by the GNAT team at New York University. -- 22-- Extensive contributions were provided by Ada Core Technologies Inc. -- 23-- -- 24------------------------------------------------------------------------------ 25 26with Atree; use Atree; 27with Debug; use Debug; 28with Einfo; use Einfo; 29with Einfo.Entities; use Einfo.Entities; 30with Einfo.Utils; use Einfo.Utils; 31with Elists; use Elists; 32with Errout; use Errout; 33with Exp_Disp; use Exp_Disp; 34with Exp_Tss; use Exp_Tss; 35with Exp_Util; use Exp_Util; 36with Freeze; use Freeze; 37with Ghost; use Ghost; 38with Impunit; use Impunit; 39with Lib; use Lib; 40with Lib.Load; use Lib.Load; 41with Lib.Xref; use Lib.Xref; 42with Namet; use Namet; 43with Namet.Sp; use Namet.Sp; 44with Nlists; use Nlists; 45with Nmake; use Nmake; 46with Opt; use Opt; 47with Output; use Output; 48with Restrict; use Restrict; 49with Rident; use Rident; 50with Rtsfind; use Rtsfind; 51with Sem; use Sem; 52with Sem_Aux; use Sem_Aux; 53with Sem_Cat; use Sem_Cat; 54with Sem_Ch3; use Sem_Ch3; 55with Sem_Ch4; use Sem_Ch4; 56with Sem_Ch6; use Sem_Ch6; 57with Sem_Ch10; use Sem_Ch10; 58with Sem_Ch12; use Sem_Ch12; 59with Sem_Ch13; use Sem_Ch13; 60with Sem_Dim; use Sem_Dim; 61with Sem_Disp; use Sem_Disp; 62with Sem_Dist; use Sem_Dist; 63with Sem_Elab; use Sem_Elab; 64with Sem_Eval; use Sem_Eval; 65with Sem_Prag; use Sem_Prag; 66with Sem_Res; use Sem_Res; 67with Sem_Util; use Sem_Util; 68with Sem_Type; use Sem_Type; 69with Stand; use Stand; 70with Sinfo; use Sinfo; 71with Sinfo.Nodes; use Sinfo.Nodes; 72with Sinfo.Utils; use Sinfo.Utils; 73with Sinfo.CN; use Sinfo.CN; 74with Snames; use Snames; 75with Style; 76with Table; 77with Tbuild; use Tbuild; 78with Uintp; use Uintp; 79 80package body Sem_Ch8 is 81 82 ------------------------------------ 83 -- Visibility and Name Resolution -- 84 ------------------------------------ 85 86 -- This package handles name resolution and the collection of possible 87 -- interpretations for overloaded names, prior to overload resolution. 88 89 -- Name resolution is the process that establishes a mapping between source 90 -- identifiers and the entities they denote at each point in the program. 91 -- Each entity is represented by a defining occurrence. Each identifier 92 -- that denotes an entity points to the corresponding defining occurrence. 93 -- This is the entity of the applied occurrence. Each occurrence holds 94 -- an index into the names table, where source identifiers are stored. 95 96 -- Each entry in the names table for an identifier or designator uses the 97 -- Info pointer to hold a link to the currently visible entity that has 98 -- this name (see subprograms Get_Name_Entity_Id and Set_Name_Entity_Id 99 -- in package Sem_Util). The visibility is initialized at the beginning of 100 -- semantic processing to make entities in package Standard immediately 101 -- visible. The visibility table is used in a more subtle way when 102 -- compiling subunits (see below). 103 104 -- Entities that have the same name (i.e. homonyms) are chained. In the 105 -- case of overloaded entities, this chain holds all the possible meanings 106 -- of a given identifier. The process of overload resolution uses type 107 -- information to select from this chain the unique meaning of a given 108 -- identifier. 109 110 -- Entities are also chained in their scope, through the Next_Entity link. 111 -- As a consequence, the name space is organized as a sparse matrix, where 112 -- each row corresponds to a scope, and each column to a source identifier. 113 -- Open scopes, that is to say scopes currently being compiled, have their 114 -- corresponding rows of entities in order, innermost scope first. 115 116 -- The scopes of packages that are mentioned in context clauses appear in 117 -- no particular order, interspersed among open scopes. This is because 118 -- in the course of analyzing the context of a compilation, a package 119 -- declaration is first an open scope, and subsequently an element of the 120 -- context. If subunits or child units are present, a parent unit may 121 -- appear under various guises at various times in the compilation. 122 123 -- When the compilation of the innermost scope is complete, the entities 124 -- defined therein are no longer visible. If the scope is not a package 125 -- declaration, these entities are never visible subsequently, and can be 126 -- removed from visibility chains. If the scope is a package declaration, 127 -- its visible declarations may still be accessible. Therefore the entities 128 -- defined in such a scope are left on the visibility chains, and only 129 -- their visibility (immediately visibility or potential use-visibility) 130 -- is affected. 131 132 -- The ordering of homonyms on their chain does not necessarily follow 133 -- the order of their corresponding scopes on the scope stack. For 134 -- example, if package P and the enclosing scope both contain entities 135 -- named E, then when compiling the package body the chain for E will 136 -- hold the global entity first, and the local one (corresponding to 137 -- the current inner scope) next. As a result, name resolution routines 138 -- do not assume any relative ordering of the homonym chains, either 139 -- for scope nesting or to order of appearance of context clauses. 140 141 -- When compiling a child unit, entities in the parent scope are always 142 -- immediately visible. When compiling the body of a child unit, private 143 -- entities in the parent must also be made immediately visible. There 144 -- are separate routines to make the visible and private declarations 145 -- visible at various times (see package Sem_Ch7). 146 147 -- +--------+ +-----+ 148 -- | In use |-------->| EU1 |--------------------------> 149 -- +--------+ +-----+ 150 -- | | 151 -- +--------+ +-----+ +-----+ 152 -- | Stand. |---------------->| ES1 |--------------->| ES2 |---> 153 -- +--------+ +-----+ +-----+ 154 -- | | 155 -- +---------+ | +-----+ 156 -- | with'ed |------------------------------>| EW2 |---> 157 -- +---------+ | +-----+ 158 -- | | 159 -- +--------+ +-----+ +-----+ 160 -- | Scope2 |---------------->| E12 |--------------->| E22 |---> 161 -- +--------+ +-----+ +-----+ 162 -- | | 163 -- +--------+ +-----+ +-----+ 164 -- | Scope1 |---------------->| E11 |--------------->| E12 |---> 165 -- +--------+ +-----+ +-----+ 166 -- ^ | | 167 -- | | | 168 -- | +---------+ | | 169 -- | | with'ed |-----------------------------------------> 170 -- | +---------+ | | 171 -- | | | 172 -- Scope stack | | 173 -- (innermost first) | | 174 -- +----------------------------+ 175 -- Names table => | Id1 | | | | Id2 | 176 -- +----------------------------+ 177 178 -- Name resolution must deal with several syntactic forms: simple names, 179 -- qualified names, indexed names, and various forms of calls. 180 181 -- Each identifier points to an entry in the names table. The resolution 182 -- of a simple name consists in traversing the homonym chain, starting 183 -- from the names table. If an entry is immediately visible, it is the one 184 -- designated by the identifier. If only potentially use-visible entities 185 -- are on the chain, we must verify that they do not hide each other. If 186 -- the entity we find is overloadable, we collect all other overloadable 187 -- entities on the chain as long as they are not hidden. 188 -- 189 -- To resolve expanded names, we must find the entity at the intersection 190 -- of the entity chain for the scope (the prefix) and the homonym chain 191 -- for the selector. In general, homonym chains will be much shorter than 192 -- entity chains, so it is preferable to start from the names table as 193 -- well. If the entity found is overloadable, we must collect all other 194 -- interpretations that are defined in the scope denoted by the prefix. 195 196 -- For records, protected types, and tasks, their local entities are 197 -- removed from visibility chains on exit from the corresponding scope. 198 -- From the outside, these entities are always accessed by selected 199 -- notation, and the entity chain for the record type, protected type, 200 -- etc. is traversed sequentially in order to find the designated entity. 201 202 -- The discriminants of a type and the operations of a protected type or 203 -- task are unchained on exit from the first view of the type, (such as 204 -- a private or incomplete type declaration, or a protected type speci- 205 -- fication) and re-chained when compiling the second view. 206 207 -- In the case of operators, we do not make operators on derived types 208 -- explicit. As a result, the notation P."+" may denote either a user- 209 -- defined function with name "+", or else an implicit declaration of the 210 -- operator "+" in package P. The resolution of expanded names always 211 -- tries to resolve an operator name as such an implicitly defined entity, 212 -- in addition to looking for explicit declarations. 213 214 -- All forms of names that denote entities (simple names, expanded names, 215 -- character literals in some cases) have a Entity attribute, which 216 -- identifies the entity denoted by the name. 217 218 --------------------- 219 -- The Scope Stack -- 220 --------------------- 221 222 -- The Scope stack keeps track of the scopes currently been compiled. 223 -- Every entity that contains declarations (including records) is placed 224 -- on the scope stack while it is being processed, and removed at the end. 225 -- Whenever a non-package scope is exited, the entities defined therein 226 -- are removed from the visibility table, so that entities in outer scopes 227 -- become visible (see previous description). On entry to Sem, the scope 228 -- stack only contains the package Standard. As usual, subunits complicate 229 -- this picture ever so slightly. 230 231 -- The Rtsfind mechanism can force a call to Semantics while another 232 -- compilation is in progress. The unit retrieved by Rtsfind must be 233 -- compiled in its own context, and has no access to the visibility of 234 -- the unit currently being compiled. The procedures Save_Scope_Stack and 235 -- Restore_Scope_Stack make entities in current open scopes invisible 236 -- before compiling the retrieved unit, and restore the compilation 237 -- environment afterwards. 238 239 ------------------------ 240 -- Compiling subunits -- 241 ------------------------ 242 243 -- Subunits must be compiled in the environment of the corresponding stub, 244 -- that is to say with the same visibility into the parent (and its 245 -- context) that is available at the point of the stub declaration, but 246 -- with the additional visibility provided by the context clause of the 247 -- subunit itself. As a result, compilation of a subunit forces compilation 248 -- of the parent (see description in lib-). At the point of the stub 249 -- declaration, Analyze is called recursively to compile the proper body of 250 -- the subunit, but without reinitializing the names table, nor the scope 251 -- stack (i.e. standard is not pushed on the stack). In this fashion the 252 -- context of the subunit is added to the context of the parent, and the 253 -- subunit is compiled in the correct environment. Note that in the course 254 -- of processing the context of a subunit, Standard will appear twice on 255 -- the scope stack: once for the parent of the subunit, and once for the 256 -- unit in the context clause being compiled. However, the two sets of 257 -- entities are not linked by homonym chains, so that the compilation of 258 -- any context unit happens in a fresh visibility environment. 259 260 ------------------------------- 261 -- Processing of USE Clauses -- 262 ------------------------------- 263 264 -- Every defining occurrence has a flag indicating if it is potentially use 265 -- visible. Resolution of simple names examines this flag. The processing 266 -- of use clauses consists in setting this flag on all visible entities 267 -- defined in the corresponding package. On exit from the scope of the use 268 -- clause, the corresponding flag must be reset. However, a package may 269 -- appear in several nested use clauses (pathological but legal, alas) 270 -- which forces us to use a slightly more involved scheme: 271 272 -- a) The defining occurrence for a package holds a flag -In_Use- to 273 -- indicate that it is currently in the scope of a use clause. If a 274 -- redundant use clause is encountered, then the corresponding occurrence 275 -- of the package name is flagged -Redundant_Use-. 276 277 -- b) On exit from a scope, the use clauses in its declarative part are 278 -- scanned. The visibility flag is reset in all entities declared in 279 -- package named in a use clause, as long as the package is not flagged 280 -- as being in a redundant use clause (in which case the outer use 281 -- clause is still in effect, and the direct visibility of its entities 282 -- must be retained). 283 284 -- Note that entities are not removed from their homonym chains on exit 285 -- from the package specification. A subsequent use clause does not need 286 -- to rechain the visible entities, but only to establish their direct 287 -- visibility. 288 289 ----------------------------------- 290 -- Handling private declarations -- 291 ----------------------------------- 292 293 -- The principle that each entity has a single defining occurrence clashes 294 -- with the presence of two separate definitions for private types: the 295 -- first is the private type declaration, and second is the full type 296 -- declaration. It is important that all references to the type point to 297 -- the same defining occurrence, namely the first one. To enforce the two 298 -- separate views of the entity, the corresponding information is swapped 299 -- between the two declarations. Outside of the package, the defining 300 -- occurrence only contains the private declaration information, while in 301 -- the private part and the body of the package the defining occurrence 302 -- contains the full declaration. To simplify the swap, the defining 303 -- occurrence that currently holds the private declaration points to the 304 -- full declaration. During semantic processing the defining occurrence 305 -- also points to a list of private dependents, that is to say access types 306 -- or composite types whose designated types or component types are 307 -- subtypes or derived types of the private type in question. After the 308 -- full declaration has been seen, the private dependents are updated to 309 -- indicate that they have full definitions. 310 311 ------------------------------------ 312 -- Handling of Undefined Messages -- 313 ------------------------------------ 314 315 -- In normal mode, only the first use of an undefined identifier generates 316 -- a message. The table Urefs is used to record error messages that have 317 -- been issued so that second and subsequent ones do not generate further 318 -- messages. However, the second reference causes text to be added to the 319 -- original undefined message noting "(more references follow)". The 320 -- full error list option (-gnatf) forces messages to be generated for 321 -- every reference and disconnects the use of this table. 322 323 type Uref_Entry is record 324 Node : Node_Id; 325 -- Node for identifier for which original message was posted. The 326 -- Chars field of this identifier is used to detect later references 327 -- to the same identifier. 328 329 Err : Error_Msg_Id; 330 -- Records error message Id of original undefined message. Reset to 331 -- No_Error_Msg after the second occurrence, where it is used to add 332 -- text to the original message as described above. 333 334 Nvis : Boolean; 335 -- Set if the message is not visible rather than undefined 336 337 Loc : Source_Ptr; 338 -- Records location of error message. Used to make sure that we do 339 -- not consider a, b : undefined as two separate instances, which 340 -- would otherwise happen, since the parser converts this sequence 341 -- to a : undefined; b : undefined. 342 343 end record; 344 345 package Urefs is new Table.Table ( 346 Table_Component_Type => Uref_Entry, 347 Table_Index_Type => Nat, 348 Table_Low_Bound => 1, 349 Table_Initial => 10, 350 Table_Increment => 100, 351 Table_Name => "Urefs"); 352 353 Candidate_Renaming : Entity_Id; 354 -- Holds a candidate interpretation that appears in a subprogram renaming 355 -- declaration and does not match the given specification, but matches at 356 -- least on the first formal. Allows better error message when given 357 -- specification omits defaulted parameters, a common error. 358 359 ----------------------- 360 -- Local Subprograms -- 361 ----------------------- 362 363 procedure Analyze_Generic_Renaming 364 (N : Node_Id; 365 K : Entity_Kind); 366 -- Common processing for all three kinds of generic renaming declarations. 367 -- Enter new name and indicate that it renames the generic unit. 368 369 procedure Analyze_Renamed_Character 370 (N : Node_Id; 371 New_S : Entity_Id; 372 Is_Body : Boolean); 373 -- Renamed entity is given by a character literal, which must belong 374 -- to the return type of the new entity. Is_Body indicates whether the 375 -- declaration is a renaming_as_body. If the original declaration has 376 -- already been frozen (because of an intervening body, e.g.) the body of 377 -- the function must be built now. The same applies to the following 378 -- various renaming procedures. 379 380 procedure Analyze_Renamed_Dereference 381 (N : Node_Id; 382 New_S : Entity_Id; 383 Is_Body : Boolean); 384 -- Renamed entity is given by an explicit dereference. Prefix must be a 385 -- conformant access_to_subprogram type. 386 387 procedure Analyze_Renamed_Entry 388 (N : Node_Id; 389 New_S : Entity_Id; 390 Is_Body : Boolean); 391 -- If the renamed entity in a subprogram renaming is an entry or protected 392 -- subprogram, build a body for the new entity whose only statement is a 393 -- call to the renamed entity. 394 395 procedure Analyze_Renamed_Family_Member 396 (N : Node_Id; 397 New_S : Entity_Id; 398 Is_Body : Boolean); 399 -- Used when the renamed entity is an indexed component. The prefix must 400 -- denote an entry family. 401 402 procedure Analyze_Renamed_Primitive_Operation 403 (N : Node_Id; 404 New_S : Entity_Id; 405 Is_Body : Boolean); 406 -- If the renamed entity in a subprogram renaming is a primitive operation 407 -- or a class-wide operation in prefix form, save the target object, 408 -- which must be added to the list of actuals in any subsequent call. 409 -- The renaming operation is intrinsic because the compiler must in 410 -- fact generate a wrapper for it (6.3.1 (10 1/2)). 411 412 procedure Attribute_Renaming (N : Node_Id); 413 -- Analyze renaming of attribute as subprogram. The renaming declaration N 414 -- is rewritten as a subprogram body that returns the attribute reference 415 -- applied to the formals of the function. 416 417 procedure Set_Entity_Or_Discriminal (N : Node_Id; E : Entity_Id); 418 -- Set Entity, with style check if need be. For a discriminant reference, 419 -- replace by the corresponding discriminal, i.e. the parameter of the 420 -- initialization procedure that corresponds to the discriminant. 421 422 procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id); 423 -- A renaming_as_body may occur after the entity of the original decla- 424 -- ration has been frozen. In that case, the body of the new entity must 425 -- be built now, because the usual mechanism of building the renamed 426 -- body at the point of freezing will not work. Subp is the subprogram 427 -- for which N provides the Renaming_As_Body. 428 429 procedure Check_In_Previous_With_Clause (N, Nam : Node_Id); 430 -- N is a use_package clause and Nam the package name, or N is a use_type 431 -- clause and Nam is the prefix of the type name. In either case, verify 432 -- that the package is visible at that point in the context: either it 433 -- appears in a previous with_clause, or because it is a fully qualified 434 -- name and the root ancestor appears in a previous with_clause. 435 436 procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id); 437 -- Verify that the entity in a renaming declaration that is a library unit 438 -- is itself a library unit and not a nested unit or subunit. Also check 439 -- that if the renaming is a child unit of a generic parent, then the 440 -- renamed unit must also be a child unit of that parent. Finally, verify 441 -- that a renamed generic unit is not an implicit child declared within 442 -- an instance of the parent. 443 444 procedure Chain_Use_Clause (N : Node_Id); 445 -- Chain use clause onto list of uses clauses headed by First_Use_Clause in 446 -- the proper scope table entry. This is usually the current scope, but it 447 -- will be an inner scope when installing the use clauses of the private 448 -- declarations of a parent unit prior to compiling the private part of a 449 -- child unit. This chain is traversed when installing/removing use clauses 450 -- when compiling a subunit or instantiating a generic body on the fly, 451 -- when it is necessary to save and restore full environments. 452 453 function Enclosing_Instance return Entity_Id; 454 -- In an instance nested within another one, several semantic checks are 455 -- unnecessary because the legality of the nested instance has been checked 456 -- in the enclosing generic unit. This applies in particular to legality 457 -- checks on actuals for formal subprograms of the inner instance, which 458 -- are checked as subprogram renamings, and may be complicated by confusion 459 -- in private/full views. This function returns the instance enclosing the 460 -- current one if there is such, else it returns Empty. 461 -- 462 -- If the renaming determines the entity for the default of a formal 463 -- subprogram nested within another instance, choose the innermost 464 -- candidate. This is because if the formal has a box, and we are within 465 -- an enclosing instance where some candidate interpretations are local 466 -- to this enclosing instance, we know that the default was properly 467 -- resolved when analyzing the generic, so we prefer the local 468 -- candidates to those that are external. This is not always the case 469 -- but is a reasonable heuristic on the use of nested generics. The 470 -- proper solution requires a full renaming model. 471 472 function Entity_Of_Unit (U : Node_Id) return Entity_Id; 473 -- Return the appropriate entity for determining which unit has a deeper 474 -- scope: the defining entity for U, unless U is a package instance, in 475 -- which case we retrieve the entity of the instance spec. 476 477 procedure Find_Expanded_Name (N : Node_Id); 478 -- The input is a selected component known to be an expanded name. Verify 479 -- legality of selector given the scope denoted by prefix, and change node 480 -- N into a expanded name with a properly set Entity field. 481 482 function Find_First_Use (Use_Clause : Node_Id) return Node_Id; 483 -- Find the most previous use clause (that is, the first one to appear in 484 -- the source) by traversing the previous clause chain that exists in both 485 -- N_Use_Package_Clause nodes and N_Use_Type_Clause nodes. 486 487 function Find_Renamed_Entity 488 (N : Node_Id; 489 Nam : Node_Id; 490 New_S : Entity_Id; 491 Is_Actual : Boolean := False) return Entity_Id; 492 -- Find the renamed entity that corresponds to the given parameter profile 493 -- in a subprogram renaming declaration. The renamed entity may be an 494 -- operator, a subprogram, an entry, or a protected operation. Is_Actual 495 -- indicates that the renaming is the one generated for an actual subpro- 496 -- gram in an instance, for which special visibility checks apply. 497 498 function Has_Implicit_Character_Literal (N : Node_Id) return Boolean; 499 -- Find a type derived from Character or Wide_Character in the prefix of N. 500 -- Used to resolved qualified names whose selector is a character literal. 501 502 function Has_Private_With (E : Entity_Id) return Boolean; 503 -- Ada 2005 (AI-262): Determines if the current compilation unit has a 504 -- private with on E. 505 506 function Has_Components (Typ : Entity_Id) return Boolean; 507 -- Determine if given type has components, i.e. is either a record type or 508 -- type or a type that has discriminants. 509 510 function Has_Implicit_Operator (N : Node_Id) return Boolean; 511 -- N is an expanded name whose selector is an operator name (e.g. P."+"). 512 -- declarative part contains an implicit declaration of an operator if it 513 -- has a declaration of a type to which one of the predefined operators 514 -- apply. The existence of this routine is an implementation artifact. A 515 -- more straightforward but more space-consuming choice would be to make 516 -- all inherited operators explicit in the symbol table. 517 518 procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id); 519 -- A subprogram defined by a renaming declaration inherits the parameter 520 -- profile of the renamed entity. The subtypes given in the subprogram 521 -- specification are discarded and replaced with those of the renamed 522 -- subprogram, which are then used to recheck the default values. 523 524 function Most_Descendant_Use_Clause 525 (Clause1 : Entity_Id; 526 Clause2 : Entity_Id) return Entity_Id; 527 -- Determine which use clause parameter is the most descendant in terms of 528 -- scope. 529 530 procedure Premature_Usage (N : Node_Id); 531 -- Diagnose usage of an entity before it is visible 532 533 procedure Use_One_Package 534 (N : Node_Id; 535 Pack_Name : Entity_Id := Empty; 536 Force : Boolean := False); 537 -- Make visible entities declared in package P potentially use-visible 538 -- in the current context. Also used in the analysis of subunits, when 539 -- re-installing use clauses of parent units. N is the use_clause that 540 -- names P (and possibly other packages). 541 542 procedure Use_One_Type 543 (Id : Node_Id; 544 Installed : Boolean := False; 545 Force : Boolean := False); 546 -- Id is the subtype mark from a use_type_clause. This procedure makes 547 -- the primitive operators of the type potentially use-visible. The 548 -- boolean flag Installed indicates that the clause is being reinstalled 549 -- after previous analysis, and primitive operations are already chained 550 -- on the Used_Operations list of the clause. 551 552 procedure Write_Info; 553 -- Write debugging information on entities declared in current scope 554 555 -------------------------------- 556 -- Analyze_Exception_Renaming -- 557 -------------------------------- 558 559 -- The language only allows a single identifier, but the tree holds an 560 -- identifier list. The parser has already issued an error message if 561 -- there is more than one element in the list. 562 563 procedure Analyze_Exception_Renaming (N : Node_Id) is 564 Id : constant Entity_Id := Defining_Entity (N); 565 Nam : constant Node_Id := Name (N); 566 567 begin 568 Enter_Name (Id); 569 Analyze (Nam); 570 571 Mutate_Ekind (Id, E_Exception); 572 Set_Etype (Id, Standard_Exception_Type); 573 Set_Is_Pure (Id, Is_Pure (Current_Scope)); 574 575 if Is_Entity_Name (Nam) 576 and then Present (Entity (Nam)) 577 and then Ekind (Entity (Nam)) = E_Exception 578 then 579 if Present (Renamed_Entity (Entity (Nam))) then 580 Set_Renamed_Entity (Id, Renamed_Entity (Entity (Nam))); 581 else 582 Set_Renamed_Entity (Id, Entity (Nam)); 583 end if; 584 585 -- The exception renaming declaration may become Ghost if it renames 586 -- a Ghost entity. 587 588 Mark_Ghost_Renaming (N, Entity (Nam)); 589 else 590 Error_Msg_N ("invalid exception name in renaming", Nam); 591 end if; 592 593 -- Implementation-defined aspect specifications can appear in a renaming 594 -- declaration, but not language-defined ones. The call to procedure 595 -- Analyze_Aspect_Specifications will take care of this error check. 596 597 if Has_Aspects (N) then 598 Analyze_Aspect_Specifications (N, Id); 599 end if; 600 end Analyze_Exception_Renaming; 601 602 --------------------------- 603 -- Analyze_Expanded_Name -- 604 --------------------------- 605 606 procedure Analyze_Expanded_Name (N : Node_Id) is 607 begin 608 -- If the entity pointer is already set, this is an internal node, or a 609 -- node that is analyzed more than once, after a tree modification. In 610 -- such a case there is no resolution to perform, just set the type. In 611 -- either case, start by analyzing the prefix. 612 613 Analyze (Prefix (N)); 614 615 if Present (Entity (N)) then 616 if Is_Type (Entity (N)) then 617 Set_Etype (N, Entity (N)); 618 else 619 Set_Etype (N, Etype (Entity (N))); 620 end if; 621 622 else 623 Find_Expanded_Name (N); 624 end if; 625 626 -- In either case, propagate dimension of entity to expanded name 627 628 Analyze_Dimension (N); 629 end Analyze_Expanded_Name; 630 631 --------------------------------------- 632 -- Analyze_Generic_Function_Renaming -- 633 --------------------------------------- 634 635 procedure Analyze_Generic_Function_Renaming (N : Node_Id) is 636 begin 637 Analyze_Generic_Renaming (N, E_Generic_Function); 638 end Analyze_Generic_Function_Renaming; 639 640 -------------------------------------- 641 -- Analyze_Generic_Package_Renaming -- 642 -------------------------------------- 643 644 procedure Analyze_Generic_Package_Renaming (N : Node_Id) is 645 begin 646 -- Test for the Text_IO special unit case here, since we may be renaming 647 -- one of the subpackages of Text_IO, then join common routine. 648 649 Check_Text_IO_Special_Unit (Name (N)); 650 651 Analyze_Generic_Renaming (N, E_Generic_Package); 652 end Analyze_Generic_Package_Renaming; 653 654 ---------------------------------------- 655 -- Analyze_Generic_Procedure_Renaming -- 656 ---------------------------------------- 657 658 procedure Analyze_Generic_Procedure_Renaming (N : Node_Id) is 659 begin 660 Analyze_Generic_Renaming (N, E_Generic_Procedure); 661 end Analyze_Generic_Procedure_Renaming; 662 663 ------------------------------ 664 -- Analyze_Generic_Renaming -- 665 ------------------------------ 666 667 procedure Analyze_Generic_Renaming 668 (N : Node_Id; 669 K : Entity_Kind) 670 is 671 New_P : constant Entity_Id := Defining_Entity (N); 672 Inst : Boolean := False; 673 Old_P : Entity_Id; 674 675 begin 676 if Name (N) = Error then 677 return; 678 end if; 679 680 Generate_Definition (New_P); 681 682 if Current_Scope /= Standard_Standard then 683 Set_Is_Pure (New_P, Is_Pure (Current_Scope)); 684 end if; 685 686 if Nkind (Name (N)) = N_Selected_Component then 687 Check_Generic_Child_Unit (Name (N), Inst); 688 else 689 Analyze (Name (N)); 690 end if; 691 692 if not Is_Entity_Name (Name (N)) then 693 Error_Msg_N ("expect entity name in renaming declaration", Name (N)); 694 Old_P := Any_Id; 695 else 696 Old_P := Entity (Name (N)); 697 end if; 698 699 Enter_Name (New_P); 700 Mutate_Ekind (New_P, K); 701 702 if Etype (Old_P) = Any_Type then 703 null; 704 705 elsif Ekind (Old_P) /= K then 706 Error_Msg_N ("invalid generic unit name", Name (N)); 707 708 else 709 if Present (Renamed_Entity (Old_P)) then 710 Set_Renamed_Entity (New_P, Renamed_Entity (Old_P)); 711 else 712 Set_Renamed_Entity (New_P, Old_P); 713 end if; 714 715 -- The generic renaming declaration may become Ghost if it renames a 716 -- Ghost entity. 717 718 Mark_Ghost_Renaming (N, Old_P); 719 720 Set_Is_Pure (New_P, Is_Pure (Old_P)); 721 Set_Is_Preelaborated (New_P, Is_Preelaborated (Old_P)); 722 723 Set_Etype (New_P, Etype (Old_P)); 724 Set_Has_Completion (New_P); 725 726 if In_Open_Scopes (Old_P) then 727 Error_Msg_N ("within its scope, generic denotes its instance", N); 728 end if; 729 730 -- For subprograms, propagate the Intrinsic flag, to allow, e.g. 731 -- renamings and subsequent instantiations of Unchecked_Conversion. 732 733 if Is_Generic_Subprogram (Old_P) then 734 Set_Is_Intrinsic_Subprogram 735 (New_P, Is_Intrinsic_Subprogram (Old_P)); 736 end if; 737 738 Check_Library_Unit_Renaming (N, Old_P); 739 end if; 740 741 -- Implementation-defined aspect specifications can appear in a renaming 742 -- declaration, but not language-defined ones. The call to procedure 743 -- Analyze_Aspect_Specifications will take care of this error check. 744 745 if Has_Aspects (N) then 746 Analyze_Aspect_Specifications (N, New_P); 747 end if; 748 end Analyze_Generic_Renaming; 749 750 ----------------------------- 751 -- Analyze_Object_Renaming -- 752 ----------------------------- 753 754 procedure Analyze_Object_Renaming (N : Node_Id) is 755 Id : constant Entity_Id := Defining_Identifier (N); 756 Loc : constant Source_Ptr := Sloc (N); 757 Nam : constant Node_Id := Name (N); 758 Is_Object_Ref : Boolean; 759 Dec : Node_Id; 760 T : Entity_Id; 761 T2 : Entity_Id; 762 Q : Node_Id; 763 764 procedure Check_Constrained_Object; 765 -- If the nominal type is unconstrained but the renamed object is 766 -- constrained, as can happen with renaming an explicit dereference or 767 -- a function return, build a constrained subtype from the object. If 768 -- the renaming is for a formal in an accept statement, the analysis 769 -- has already established its actual subtype. This is only relevant 770 -- if the renamed object is an explicit dereference. 771 772 function Get_Object_Name (Nod : Node_Id) return Node_Id; 773 -- Obtain the name of the object from node Nod which is being renamed by 774 -- the object renaming declaration N. 775 776 function Find_Raise_Node (N : Node_Id) return Traverse_Result; 777 -- Process one node in search for N_Raise_xxx_Error nodes. 778 -- Return Abandon if found, OK otherwise. 779 780 --------------------- 781 -- Find_Raise_Node -- 782 --------------------- 783 784 function Find_Raise_Node (N : Node_Id) return Traverse_Result is 785 begin 786 if Nkind (N) in N_Raise_xxx_Error then 787 return Abandon; 788 else 789 return OK; 790 end if; 791 end Find_Raise_Node; 792 793 ------------------------ 794 -- No_Raise_xxx_Error -- 795 ------------------------ 796 797 function No_Raise_xxx_Error is new Traverse_Func (Find_Raise_Node); 798 -- Traverse tree to look for a N_Raise_xxx_Error node and returns 799 -- Abandon if so and OK if none found. 800 801 ------------------------------ 802 -- Check_Constrained_Object -- 803 ------------------------------ 804 805 procedure Check_Constrained_Object is 806 Typ : constant Entity_Id := Etype (Nam); 807 Subt : Entity_Id; 808 Loop_Scheme : Node_Id; 809 810 begin 811 if Nkind (Nam) in N_Function_Call | N_Explicit_Dereference 812 and then Is_Composite_Type (Typ) 813 and then not Is_Constrained (Typ) 814 and then not Has_Unknown_Discriminants (Typ) 815 and then Expander_Active 816 then 817 -- If Actual_Subtype is already set, nothing to do 818 819 if Ekind (Id) in E_Variable | E_Constant 820 and then Present (Actual_Subtype (Id)) 821 then 822 null; 823 824 -- A renaming of an unchecked union has no actual subtype 825 826 elsif Is_Unchecked_Union (Typ) then 827 null; 828 829 -- If a record is limited its size is invariant. This is the case 830 -- in particular with record types with an access discriminant 831 -- that are used in iterators. This is an optimization, but it 832 -- also prevents typing anomalies when the prefix is further 833 -- expanded. 834 835 -- Note that we cannot just use the Is_Limited_Record flag because 836 -- it does not apply to records with limited components, for which 837 -- this syntactic flag is not set, but whose size is also fixed. 838 839 -- Note also that we need to build the constrained subtype for an 840 -- array in order to make the bounds explicit in most cases, but 841 -- not if the object comes from an extended return statement, as 842 -- this would create dangling references to them later on. 843 844 elsif Is_Limited_Type (Typ) 845 and then (not Is_Array_Type (Typ) or else Is_Return_Object (Id)) 846 then 847 null; 848 849 else 850 Subt := Make_Temporary (Loc, 'T'); 851 Remove_Side_Effects (Nam); 852 Insert_Action (N, 853 Make_Subtype_Declaration (Loc, 854 Defining_Identifier => Subt, 855 Subtype_Indication => 856 Make_Subtype_From_Expr (Nam, Typ))); 857 Rewrite (Subtype_Mark (N), New_Occurrence_Of (Subt, Loc)); 858 Set_Etype (Nam, Subt); 859 860 -- Suppress discriminant checks on this subtype if the original 861 -- type has defaulted discriminants and Id is a "for of" loop 862 -- iterator. 863 864 if Has_Defaulted_Discriminants (Typ) 865 and then Nkind (Original_Node (Parent (N))) = N_Loop_Statement 866 then 867 Loop_Scheme := Iteration_Scheme (Original_Node (Parent (N))); 868 869 if Present (Loop_Scheme) 870 and then Present (Iterator_Specification (Loop_Scheme)) 871 and then 872 Defining_Identifier 873 (Iterator_Specification (Loop_Scheme)) = Id 874 then 875 Set_Checks_May_Be_Suppressed (Subt); 876 Push_Local_Suppress_Stack_Entry 877 (Entity => Subt, 878 Check => Discriminant_Check, 879 Suppress => True); 880 end if; 881 end if; 882 883 -- Freeze subtype at once, to prevent order of elaboration 884 -- issues in the backend. The renamed object exists, so its 885 -- type is already frozen in any case. 886 887 Freeze_Before (N, Subt); 888 end if; 889 end if; 890 end Check_Constrained_Object; 891 892 --------------------- 893 -- Get_Object_Name -- 894 --------------------- 895 896 function Get_Object_Name (Nod : Node_Id) return Node_Id is 897 Obj_Nam : Node_Id; 898 899 begin 900 Obj_Nam := Nod; 901 while Present (Obj_Nam) loop 902 case Nkind (Obj_Nam) is 903 when N_Attribute_Reference 904 | N_Explicit_Dereference 905 | N_Indexed_Component 906 | N_Slice 907 => 908 Obj_Nam := Prefix (Obj_Nam); 909 910 when N_Selected_Component => 911 Obj_Nam := Selector_Name (Obj_Nam); 912 913 when N_Qualified_Expression | N_Type_Conversion => 914 Obj_Nam := Expression (Obj_Nam); 915 916 when others => 917 exit; 918 end case; 919 end loop; 920 921 return Obj_Nam; 922 end Get_Object_Name; 923 924 -- Start of processing for Analyze_Object_Renaming 925 926 begin 927 if Nam = Error then 928 return; 929 end if; 930 931 Set_Is_Pure (Id, Is_Pure (Current_Scope)); 932 Enter_Name (Id); 933 934 -- The renaming of a component that depends on a discriminant requires 935 -- an actual subtype, because in subsequent use of the object Gigi will 936 -- be unable to locate the actual bounds. This explicit step is required 937 -- when the renaming is generated in removing side effects of an 938 -- already-analyzed expression. 939 940 if Nkind (Nam) = N_Selected_Component and then Analyzed (Nam) then 941 942 -- The object renaming declaration may become Ghost if it renames a 943 -- Ghost entity. 944 945 if Is_Entity_Name (Nam) then 946 Mark_Ghost_Renaming (N, Entity (Nam)); 947 end if; 948 949 T := Etype (Nam); 950 Dec := Build_Actual_Subtype_Of_Component (Etype (Nam), Nam); 951 952 if Present (Dec) then 953 Insert_Action (N, Dec); 954 T := Defining_Identifier (Dec); 955 Set_Etype (Nam, T); 956 end if; 957 elsif Present (Subtype_Mark (N)) 958 or else not Present (Access_Definition (N)) 959 then 960 if Present (Subtype_Mark (N)) then 961 Find_Type (Subtype_Mark (N)); 962 T := Entity (Subtype_Mark (N)); 963 Analyze (Nam); 964 965 -- AI12-0275: Case of object renaming without a subtype_mark 966 967 else 968 Analyze (Nam); 969 970 -- Normal case of no overloading in object name 971 972 if not Is_Overloaded (Nam) then 973 974 -- Catch error cases (such as attempting to rename a procedure 975 -- or package) using the shorthand form. 976 977 if No (Etype (Nam)) 978 or else Etype (Nam) = Standard_Void_Type 979 then 980 Error_Msg_N 981 ("object name or value expected in renaming", Nam); 982 983 Mutate_Ekind (Id, E_Variable); 984 Set_Etype (Id, Any_Type); 985 986 return; 987 988 else 989 T := Etype (Nam); 990 end if; 991 992 -- Case of overloaded name, which will be illegal if there's more 993 -- than one acceptable interpretation (such as overloaded function 994 -- calls). 995 996 else 997 declare 998 I : Interp_Index; 999 I1 : Interp_Index; 1000 It : Interp; 1001 It1 : Interp; 1002 Nam1 : Entity_Id; 1003 1004 begin 1005 -- More than one candidate interpretation is available 1006 1007 -- Remove procedure calls, which syntactically cannot appear 1008 -- in this context, but which cannot be removed by type 1009 -- checking, because the context does not impose a type. 1010 1011 Get_First_Interp (Nam, I, It); 1012 while Present (It.Typ) loop 1013 if It.Typ = Standard_Void_Type then 1014 Remove_Interp (I); 1015 end if; 1016 1017 Get_Next_Interp (I, It); 1018 end loop; 1019 1020 Get_First_Interp (Nam, I, It); 1021 I1 := I; 1022 It1 := It; 1023 1024 -- If there's no type present, we have an error case (such 1025 -- as overloaded procedures named in the object renaming). 1026 1027 if No (It.Typ) then 1028 Error_Msg_N 1029 ("object name or value expected in renaming", Nam); 1030 1031 Mutate_Ekind (Id, E_Variable); 1032 Set_Etype (Id, Any_Type); 1033 1034 return; 1035 end if; 1036 1037 Get_Next_Interp (I, It); 1038 1039 if Present (It.Typ) then 1040 Nam1 := It1.Nam; 1041 It1 := Disambiguate (Nam, I1, I, Any_Type); 1042 1043 if It1 = No_Interp then 1044 Error_Msg_N ("ambiguous name in object renaming", Nam); 1045 1046 Error_Msg_Sloc := Sloc (It.Nam); 1047 Error_Msg_N ("\\possible interpretation#!", Nam); 1048 1049 Error_Msg_Sloc := Sloc (Nam1); 1050 Error_Msg_N ("\\possible interpretation#!", Nam); 1051 1052 return; 1053 end if; 1054 end if; 1055 1056 Set_Etype (Nam, It1.Typ); 1057 T := It1.Typ; 1058 end; 1059 end if; 1060 1061 if Etype (Nam) = Standard_Exception_Type then 1062 Error_Msg_N 1063 ("exception requires a subtype mark in renaming", Nam); 1064 return; 1065 end if; 1066 end if; 1067 1068 -- The object renaming declaration may become Ghost if it renames a 1069 -- Ghost entity. 1070 1071 if Is_Entity_Name (Nam) then 1072 Mark_Ghost_Renaming (N, Entity (Nam)); 1073 end if; 1074 1075 -- Check against AI12-0401 here before Resolve may rewrite Nam and 1076 -- potentially generate spurious warnings. 1077 1078 -- In the case where the object_name is a qualified_expression with 1079 -- a nominal subtype T and whose expression is a name that denotes 1080 -- an object Q: 1081 -- * if T is an elementary subtype, then: 1082 -- * Q shall be a constant other than a dereference of an access 1083 -- type; or 1084 -- * the nominal subtype of Q shall be statically compatible with 1085 -- T; or 1086 -- * T shall statically match the base subtype of its type if 1087 -- scalar, or the first subtype of its type if an access type. 1088 -- * if T is a composite subtype, then Q shall be known to be 1089 -- constrained or T shall statically match the first subtype of 1090 -- its type. 1091 1092 if Nkind (Nam) = N_Qualified_Expression 1093 and then Is_Object_Reference (Expression (Nam)) 1094 then 1095 Q := Expression (Nam); 1096 1097 if (Is_Elementary_Type (T) 1098 and then 1099 not ((not Is_Variable (Q) 1100 and then Nkind (Q) /= N_Explicit_Dereference) 1101 or else Subtypes_Statically_Compatible (Etype (Q), T) 1102 or else (Is_Scalar_Type (T) 1103 and then Subtypes_Statically_Match 1104 (T, Base_Type (T))) 1105 or else (Is_Access_Type (T) 1106 and then Subtypes_Statically_Match 1107 (T, First_Subtype (T))))) 1108 or else (Is_Composite_Type (T) 1109 and then 1110 1111 -- If Q is an aggregate, Is_Constrained may not be set 1112 -- yet and its type may not be resolved yet. 1113 -- This doesn't quite correspond to the complex notion 1114 -- of "known to be constrained" but this is good enough 1115 -- for a rule which is in any case too complex. 1116 1117 not (Is_Constrained (Etype (Q)) 1118 or else Nkind (Q) = N_Aggregate 1119 or else Subtypes_Statically_Match 1120 (T, First_Subtype (T)))) 1121 then 1122 Error_Msg_N 1123 ("subtype of renamed qualified expression does not " & 1124 "statically match", N); 1125 return; 1126 end if; 1127 end if; 1128 1129 Resolve (Nam, T); 1130 1131 -- If the renamed object is a function call of a limited type, 1132 -- the expansion of the renaming is complicated by the presence 1133 -- of various temporaries and subtypes that capture constraints 1134 -- of the renamed object. Rewrite node as an object declaration, 1135 -- whose expansion is simpler. Given that the object is limited 1136 -- there is no copy involved and no performance hit. 1137 1138 if Nkind (Nam) = N_Function_Call 1139 and then Is_Limited_View (Etype (Nam)) 1140 and then not Is_Constrained (Etype (Nam)) 1141 and then Comes_From_Source (N) 1142 then 1143 Set_Etype (Id, T); 1144 Mutate_Ekind (Id, E_Constant); 1145 Rewrite (N, 1146 Make_Object_Declaration (Loc, 1147 Defining_Identifier => Id, 1148 Constant_Present => True, 1149 Object_Definition => New_Occurrence_Of (Etype (Nam), Loc), 1150 Expression => Relocate_Node (Nam))); 1151 return; 1152 end if; 1153 1154 -- Ada 2012 (AI05-149): Reject renaming of an anonymous access object 1155 -- when renaming declaration has a named access type. The Ada 2012 1156 -- coverage rules allow an anonymous access type in the context of 1157 -- an expected named general access type, but the renaming rules 1158 -- require the types to be the same. (An exception is when the type 1159 -- of the renaming is also an anonymous access type, which can only 1160 -- happen due to a renaming created by the expander.) 1161 1162 if Nkind (Nam) = N_Type_Conversion 1163 and then not Comes_From_Source (Nam) 1164 and then Is_Anonymous_Access_Type (Etype (Expression (Nam))) 1165 and then not Is_Anonymous_Access_Type (T) 1166 then 1167 Error_Msg_NE 1168 ("cannot rename anonymous access object " 1169 & "as a named access type", Expression (Nam), T); 1170 end if; 1171 1172 -- Check that a class-wide object is not being renamed as an object 1173 -- of a specific type. The test for access types is needed to exclude 1174 -- cases where the renamed object is a dynamically tagged access 1175 -- result, such as occurs in certain expansions. 1176 1177 if Is_Tagged_Type (T) then 1178 Check_Dynamically_Tagged_Expression 1179 (Expr => Nam, 1180 Typ => T, 1181 Related_Nod => N); 1182 end if; 1183 1184 -- Ada 2005 (AI-230/AI-254): Access renaming 1185 1186 else pragma Assert (Present (Access_Definition (N))); 1187 T := 1188 Access_Definition 1189 (Related_Nod => N, 1190 N => Access_Definition (N)); 1191 1192 Analyze (Nam); 1193 1194 -- The object renaming declaration may become Ghost if it renames a 1195 -- Ghost entity. 1196 1197 if Is_Entity_Name (Nam) then 1198 Mark_Ghost_Renaming (N, Entity (Nam)); 1199 end if; 1200 1201 -- Ada 2005 AI05-105: if the declaration has an anonymous access 1202 -- type, the renamed object must also have an anonymous type, and 1203 -- this is a name resolution rule. This was implicit in the last part 1204 -- of the first sentence in 8.5.1(3/2), and is made explicit by this 1205 -- recent AI. 1206 1207 if not Is_Overloaded (Nam) then 1208 if Ekind (Etype (Nam)) /= Ekind (T) then 1209 Error_Msg_N 1210 ("expect anonymous access type in object renaming", N); 1211 end if; 1212 1213 else 1214 declare 1215 I : Interp_Index; 1216 It : Interp; 1217 Typ : Entity_Id := Empty; 1218 Seen : Boolean := False; 1219 1220 begin 1221 Get_First_Interp (Nam, I, It); 1222 while Present (It.Typ) loop 1223 1224 -- Renaming is ambiguous if more than one candidate 1225 -- interpretation is type-conformant with the context. 1226 1227 if Ekind (It.Typ) = Ekind (T) then 1228 if Ekind (T) = E_Anonymous_Access_Subprogram_Type 1229 and then 1230 Type_Conformant 1231 (Designated_Type (T), Designated_Type (It.Typ)) 1232 then 1233 if not Seen then 1234 Seen := True; 1235 else 1236 Error_Msg_N 1237 ("ambiguous expression in renaming", Nam); 1238 end if; 1239 1240 elsif Ekind (T) = E_Anonymous_Access_Type 1241 and then 1242 Covers (Designated_Type (T), Designated_Type (It.Typ)) 1243 then 1244 if not Seen then 1245 Seen := True; 1246 else 1247 Error_Msg_N 1248 ("ambiguous expression in renaming", Nam); 1249 end if; 1250 end if; 1251 1252 if Covers (T, It.Typ) then 1253 Typ := It.Typ; 1254 Set_Etype (Nam, Typ); 1255 Set_Is_Overloaded (Nam, False); 1256 end if; 1257 end if; 1258 1259 Get_Next_Interp (I, It); 1260 end loop; 1261 end; 1262 end if; 1263 1264 Resolve (Nam, T); 1265 1266 -- Do not perform the legality checks below when the resolution of 1267 -- the renaming name failed because the associated type is Any_Type. 1268 1269 if Etype (Nam) = Any_Type then 1270 null; 1271 1272 -- Ada 2005 (AI-231): In the case where the type is defined by an 1273 -- access_definition, the renamed entity shall be of an access-to- 1274 -- constant type if and only if the access_definition defines an 1275 -- access-to-constant type. ARM 8.5.1(4) 1276 1277 elsif Constant_Present (Access_Definition (N)) 1278 and then not Is_Access_Constant (Etype (Nam)) 1279 then 1280 Error_Msg_N 1281 ("(Ada 2005): the renamed object is not access-to-constant " 1282 & "(RM 8.5.1(6))", N); 1283 1284 elsif not Constant_Present (Access_Definition (N)) 1285 and then Is_Access_Constant (Etype (Nam)) 1286 then 1287 Error_Msg_N 1288 ("(Ada 2005): the renamed object is not access-to-variable " 1289 & "(RM 8.5.1(6))", N); 1290 end if; 1291 1292 if Is_Access_Subprogram_Type (Etype (Nam)) then 1293 Check_Subtype_Conformant 1294 (Designated_Type (T), Designated_Type (Etype (Nam))); 1295 1296 elsif not Subtypes_Statically_Match 1297 (Designated_Type (T), 1298 Available_View (Designated_Type (Etype (Nam)))) 1299 then 1300 Error_Msg_N 1301 ("subtype of renamed object does not statically match", N); 1302 end if; 1303 end if; 1304 1305 -- Special processing for renaming function return object. Some errors 1306 -- and warnings are produced only for calls that come from source. 1307 1308 if Nkind (Nam) = N_Function_Call then 1309 case Ada_Version is 1310 1311 -- Usage is illegal in Ada 83, but renamings are also introduced 1312 -- during expansion, and error does not apply to those. 1313 1314 when Ada_83 => 1315 if Comes_From_Source (N) then 1316 Error_Msg_N 1317 ("(Ada 83) cannot rename function return object", Nam); 1318 end if; 1319 1320 -- In Ada 95, warn for odd case of renaming parameterless function 1321 -- call if this is not a limited type (where this is useful). 1322 1323 when others => 1324 if Warn_On_Object_Renames_Function 1325 and then No (Parameter_Associations (Nam)) 1326 and then not Is_Limited_Type (Etype (Nam)) 1327 and then Comes_From_Source (Nam) 1328 then 1329 Error_Msg_N 1330 ("renaming function result object is suspicious?.r?", Nam); 1331 Error_Msg_NE 1332 ("\function & will be called only once?.r?", Nam, 1333 Entity (Name (Nam))); 1334 Error_Msg_N -- CODEFIX 1335 ("\suggest using an initialized constant object " 1336 & "instead?.r?", Nam); 1337 end if; 1338 end case; 1339 end if; 1340 1341 Check_Constrained_Object; 1342 1343 -- An object renaming requires an exact match of the type. Class-wide 1344 -- matching is not allowed. 1345 1346 if Is_Class_Wide_Type (T) 1347 and then Base_Type (Etype (Nam)) /= Base_Type (T) 1348 then 1349 Wrong_Type (Nam, T); 1350 end if; 1351 1352 -- We must search for an actual subtype here so that the bounds of 1353 -- objects of unconstrained types don't get dropped on the floor - such 1354 -- as with renamings of formal parameters. 1355 1356 T2 := Get_Actual_Subtype_If_Available (Nam); 1357 1358 -- Ada 2005 (AI-326): Handle wrong use of incomplete type 1359 1360 if Nkind (Nam) = N_Explicit_Dereference 1361 and then Ekind (Etype (T2)) = E_Incomplete_Type 1362 then 1363 Error_Msg_NE ("invalid use of incomplete type&", Id, T2); 1364 return; 1365 1366 elsif Ekind (Etype (T)) = E_Incomplete_Type then 1367 Error_Msg_NE ("invalid use of incomplete type&", Id, T); 1368 return; 1369 end if; 1370 1371 if Ada_Version >= Ada_2005 and then Nkind (Nam) in N_Has_Entity then 1372 declare 1373 Nam_Ent : constant Entity_Id := Entity (Get_Object_Name (Nam)); 1374 Nam_Decl : constant Node_Id := Declaration_Node (Nam_Ent); 1375 1376 begin 1377 if Has_Null_Exclusion (N) 1378 and then not Has_Null_Exclusion (Nam_Decl) 1379 then 1380 -- Ada 2005 (AI-423): If the object name denotes a generic 1381 -- formal object of a generic unit G, and the object renaming 1382 -- declaration occurs within the body of G or within the body 1383 -- of a generic unit declared within the declarative region 1384 -- of G, then the declaration of the formal object of G must 1385 -- have a null exclusion or a null-excluding subtype. 1386 1387 if Is_Formal_Object (Nam_Ent) 1388 and then In_Generic_Scope (Id) 1389 then 1390 if not Can_Never_Be_Null (Etype (Nam_Ent)) then 1391 Error_Msg_N 1392 ("object does not exclude `NULL` " 1393 & "(RM 8.5.1(4.6/2))", N); 1394 1395 elsif In_Package_Body (Scope (Id)) then 1396 Error_Msg_N 1397 ("formal object does not have a null exclusion" 1398 & "(RM 8.5.1(4.6/2))", N); 1399 end if; 1400 1401 -- Ada 2005 (AI-423): Otherwise, the subtype of the object name 1402 -- shall exclude null. 1403 1404 elsif not Can_Never_Be_Null (Etype (Nam_Ent)) then 1405 Error_Msg_N 1406 ("object does not exclude `NULL` " 1407 & "(RM 8.5.1(4.6/2))", N); 1408 1409 -- An instance is illegal if it contains a renaming that 1410 -- excludes null, and the actual does not. The renaming 1411 -- declaration has already indicated that the declaration 1412 -- of the renamed actual in the instance will raise 1413 -- constraint_error. 1414 1415 elsif Nkind (Nam_Decl) = N_Object_Declaration 1416 and then In_Instance 1417 and then 1418 Present (Corresponding_Generic_Association (Nam_Decl)) 1419 and then Nkind (Expression (Nam_Decl)) = 1420 N_Raise_Constraint_Error 1421 then 1422 Error_Msg_N 1423 ("actual does not exclude `NULL` (RM 8.5.1(4.6/2))", N); 1424 1425 -- Finally, if there is a null exclusion, the subtype mark 1426 -- must not be null-excluding. 1427 1428 elsif No (Access_Definition (N)) 1429 and then Can_Never_Be_Null (T) 1430 then 1431 Error_Msg_NE 1432 ("`NOT NULL` not allowed (& already excludes null)", 1433 N, T); 1434 1435 end if; 1436 1437 elsif Can_Never_Be_Null (T) 1438 and then not Can_Never_Be_Null (Etype (Nam_Ent)) 1439 then 1440 Error_Msg_N 1441 ("object does not exclude `NULL` (RM 8.5.1(4.6/2))", N); 1442 1443 elsif Has_Null_Exclusion (N) 1444 and then No (Access_Definition (N)) 1445 and then Can_Never_Be_Null (T) 1446 then 1447 Error_Msg_NE 1448 ("`NOT NULL` not allowed (& already excludes null)", N, T); 1449 end if; 1450 end; 1451 end if; 1452 1453 -- Set the Ekind of the entity, unless it has been set already, as is 1454 -- the case for the iteration object over a container with no variable 1455 -- indexing. In that case it's been marked as a constant, and we do not 1456 -- want to change it to a variable. 1457 1458 if Ekind (Id) /= E_Constant then 1459 Mutate_Ekind (Id, E_Variable); 1460 end if; 1461 1462 Reinit_Object_Size_Align (Id); 1463 1464 -- If N comes from source then check that the original node is an 1465 -- object reference since there may have been several rewritting and 1466 -- folding. Do not do this for N_Function_Call or N_Explicit_Dereference 1467 -- which might correspond to rewrites of e.g. N_Selected_Component 1468 -- (for example Object.Method rewriting). 1469 -- If N does not come from source then assume the tree is properly 1470 -- formed and accept any object reference. In such cases we do support 1471 -- more cases of renamings anyway, so the actual check on which renaming 1472 -- is valid is better left to the code generator as a last sanity 1473 -- check. 1474 1475 if Comes_From_Source (N) then 1476 if Nkind (Nam) in N_Function_Call | N_Explicit_Dereference then 1477 Is_Object_Ref := Is_Object_Reference (Nam); 1478 else 1479 Is_Object_Ref := Is_Object_Reference (Original_Node (Nam)); 1480 end if; 1481 else 1482 Is_Object_Ref := True; 1483 end if; 1484 1485 if T = Any_Type or else Etype (Nam) = Any_Type then 1486 return; 1487 1488 -- Verify that the renamed entity is an object or function call 1489 1490 elsif Is_Object_Ref then 1491 if Comes_From_Source (N) then 1492 if Is_Dependent_Component_Of_Mutable_Object (Nam) then 1493 Error_Msg_N 1494 ("illegal renaming of discriminant-dependent component", Nam); 1495 end if; 1496 1497 -- If the renaming comes from source and the renamed object is a 1498 -- dereference, then mark the prefix as needing debug information, 1499 -- since it might have been rewritten hence internally generated 1500 -- and Debug_Renaming_Declaration will link the renaming to it. 1501 1502 if Nkind (Nam) = N_Explicit_Dereference 1503 and then Is_Entity_Name (Prefix (Nam)) 1504 then 1505 Set_Debug_Info_Needed (Entity (Prefix (Nam))); 1506 end if; 1507 end if; 1508 1509 -- Weird but legal, equivalent to renaming a function call. Illegal 1510 -- if the literal is the result of constant-folding an attribute 1511 -- reference that is not a function. 1512 1513 elsif Is_Entity_Name (Nam) 1514 and then Ekind (Entity (Nam)) = E_Enumeration_Literal 1515 and then Nkind (Original_Node (Nam)) /= N_Attribute_Reference 1516 then 1517 null; 1518 1519 -- A named number can only be renamed without a subtype mark 1520 1521 elsif Nkind (Nam) in N_Real_Literal | N_Integer_Literal 1522 and then Present (Subtype_Mark (N)) 1523 and then Present (Original_Entity (Nam)) 1524 then 1525 Error_Msg_N ("incompatible types in renaming", Nam); 1526 1527 -- AI12-0383: Names that denote values can be renamed. 1528 -- Ignore (accept) N_Raise_xxx_Error nodes in this context. 1529 1530 elsif No_Raise_xxx_Error (Nam) = OK then 1531 Error_Msg_Ada_2022_Feature ("value in renaming", Sloc (Nam)); 1532 end if; 1533 1534 Set_Etype (Id, T2); 1535 1536 if not Is_Variable (Nam) then 1537 Mutate_Ekind (Id, E_Constant); 1538 Set_Never_Set_In_Source (Id, True); 1539 Set_Is_True_Constant (Id, True); 1540 end if; 1541 1542 -- The entity of the renaming declaration needs to reflect whether the 1543 -- renamed object is atomic, independent, volatile or VFA. These flags 1544 -- are set on the renamed object in the RM legality sense. 1545 1546 Set_Is_Atomic (Id, Is_Atomic_Object (Nam)); 1547 Set_Is_Independent (Id, Is_Independent_Object (Nam)); 1548 Set_Is_Volatile (Id, Is_Volatile_Object_Ref (Nam)); 1549 Set_Is_Volatile_Full_Access 1550 (Id, Is_Volatile_Full_Access_Object_Ref (Nam)); 1551 1552 -- Treat as volatile if we just set the Volatile flag 1553 1554 if Is_Volatile (Id) 1555 1556 -- Or if we are renaming an entity which was marked this way 1557 1558 -- Are there more cases, e.g. X(J) where X is Treat_As_Volatile ??? 1559 1560 or else (Is_Entity_Name (Nam) 1561 and then Treat_As_Volatile (Entity (Nam))) 1562 then 1563 Set_Treat_As_Volatile (Id, True); 1564 end if; 1565 1566 -- Now make the link to the renamed object 1567 1568 Set_Renamed_Object (Id, Nam); 1569 1570 -- Implementation-defined aspect specifications can appear in a renaming 1571 -- declaration, but not language-defined ones. The call to procedure 1572 -- Analyze_Aspect_Specifications will take care of this error check. 1573 1574 if Has_Aspects (N) then 1575 Analyze_Aspect_Specifications (N, Id); 1576 end if; 1577 1578 -- Deal with dimensions 1579 1580 Analyze_Dimension (N); 1581 end Analyze_Object_Renaming; 1582 1583 ------------------------------ 1584 -- Analyze_Package_Renaming -- 1585 ------------------------------ 1586 1587 procedure Analyze_Package_Renaming (N : Node_Id) is 1588 New_P : constant Entity_Id := Defining_Entity (N); 1589 Old_P : Entity_Id; 1590 Spec : Node_Id; 1591 1592 begin 1593 if Name (N) = Error then 1594 return; 1595 end if; 1596 1597 -- Check for Text_IO special unit (we may be renaming a Text_IO child) 1598 1599 Check_Text_IO_Special_Unit (Name (N)); 1600 1601 if Current_Scope /= Standard_Standard then 1602 Set_Is_Pure (New_P, Is_Pure (Current_Scope)); 1603 end if; 1604 1605 Enter_Name (New_P); 1606 Analyze (Name (N)); 1607 1608 if Is_Entity_Name (Name (N)) then 1609 Old_P := Entity (Name (N)); 1610 else 1611 Old_P := Any_Id; 1612 end if; 1613 1614 if Etype (Old_P) = Any_Type then 1615 Error_Msg_N ("expect package name in renaming", Name (N)); 1616 1617 elsif Ekind (Old_P) /= E_Package 1618 and then not (Ekind (Old_P) = E_Generic_Package 1619 and then In_Open_Scopes (Old_P)) 1620 then 1621 if Ekind (Old_P) = E_Generic_Package then 1622 Error_Msg_N 1623 ("generic package cannot be renamed as a package", Name (N)); 1624 else 1625 Error_Msg_Sloc := Sloc (Old_P); 1626 Error_Msg_NE 1627 ("expect package name in renaming, found& declared#", 1628 Name (N), Old_P); 1629 end if; 1630 1631 -- Set basic attributes to minimize cascaded errors 1632 1633 Mutate_Ekind (New_P, E_Package); 1634 Set_Etype (New_P, Standard_Void_Type); 1635 1636 elsif Present (Renamed_Entity (Old_P)) 1637 and then (From_Limited_With (Renamed_Entity (Old_P)) 1638 or else Has_Limited_View (Renamed_Entity (Old_P))) 1639 and then not 1640 Unit_Is_Visible (Cunit (Get_Source_Unit (Renamed_Entity (Old_P)))) 1641 then 1642 Error_Msg_NE 1643 ("renaming of limited view of package & not usable in this context" 1644 & " (RM 8.5.3(3.1/2))", Name (N), Renamed_Entity (Old_P)); 1645 1646 -- Set basic attributes to minimize cascaded errors 1647 1648 Mutate_Ekind (New_P, E_Package); 1649 Set_Etype (New_P, Standard_Void_Type); 1650 1651 -- Here for OK package renaming 1652 1653 else 1654 -- Entities in the old package are accessible through the renaming 1655 -- entity. The simplest implementation is to have both packages share 1656 -- the entity list. 1657 1658 Mutate_Ekind (New_P, E_Package); 1659 Set_Etype (New_P, Standard_Void_Type); 1660 1661 if Present (Renamed_Entity (Old_P)) then 1662 Set_Renamed_Entity (New_P, Renamed_Entity (Old_P)); 1663 else 1664 Set_Renamed_Entity (New_P, Old_P); 1665 end if; 1666 1667 -- The package renaming declaration may become Ghost if it renames a 1668 -- Ghost entity. 1669 1670 Mark_Ghost_Renaming (N, Old_P); 1671 1672 Set_Has_Completion (New_P); 1673 Set_First_Entity (New_P, First_Entity (Old_P)); 1674 Set_Last_Entity (New_P, Last_Entity (Old_P)); 1675 Set_First_Private_Entity (New_P, First_Private_Entity (Old_P)); 1676 Check_Library_Unit_Renaming (N, Old_P); 1677 Generate_Reference (Old_P, Name (N)); 1678 1679 -- If the renaming is in the visible part of a package, then we set 1680 -- Renamed_In_Spec for the renamed package, to prevent giving 1681 -- warnings about no entities referenced. Such a warning would be 1682 -- overenthusiastic, since clients can see entities in the renamed 1683 -- package via the visible package renaming. 1684 1685 declare 1686 Ent : constant Entity_Id := Cunit_Entity (Current_Sem_Unit); 1687 begin 1688 if Ekind (Ent) = E_Package 1689 and then not In_Private_Part (Ent) 1690 and then In_Extended_Main_Source_Unit (N) 1691 and then Ekind (Old_P) = E_Package 1692 then 1693 Set_Renamed_In_Spec (Old_P); 1694 end if; 1695 end; 1696 1697 -- If this is the renaming declaration of a package instantiation 1698 -- within itself, it is the declaration that ends the list of actuals 1699 -- for the instantiation. At this point, the subtypes that rename 1700 -- the actuals are flagged as generic, to avoid spurious ambiguities 1701 -- if the actuals for two distinct formals happen to coincide. If 1702 -- the actual is a private type, the subtype has a private completion 1703 -- that is flagged in the same fashion. 1704 1705 -- Resolution is identical to what is was in the original generic. 1706 -- On exit from the generic instance, these are turned into regular 1707 -- subtypes again, so they are compatible with types in their class. 1708 1709 if not Is_Generic_Instance (Old_P) then 1710 return; 1711 else 1712 Spec := Specification (Unit_Declaration_Node (Old_P)); 1713 end if; 1714 1715 if Nkind (Spec) = N_Package_Specification 1716 and then Present (Generic_Parent (Spec)) 1717 and then Old_P = Current_Scope 1718 and then Chars (New_P) = Chars (Generic_Parent (Spec)) 1719 then 1720 declare 1721 E : Entity_Id; 1722 1723 begin 1724 E := First_Entity (Old_P); 1725 while Present (E) and then E /= New_P loop 1726 if Is_Type (E) 1727 and then Nkind (Parent (E)) = N_Subtype_Declaration 1728 then 1729 Set_Is_Generic_Actual_Type (E); 1730 1731 if Is_Private_Type (E) 1732 and then Present (Full_View (E)) 1733 then 1734 Set_Is_Generic_Actual_Type (Full_View (E)); 1735 end if; 1736 end if; 1737 1738 Next_Entity (E); 1739 end loop; 1740 end; 1741 end if; 1742 end if; 1743 1744 -- Implementation-defined aspect specifications can appear in a renaming 1745 -- declaration, but not language-defined ones. The call to procedure 1746 -- Analyze_Aspect_Specifications will take care of this error check. 1747 1748 if Has_Aspects (N) then 1749 Analyze_Aspect_Specifications (N, New_P); 1750 end if; 1751 end Analyze_Package_Renaming; 1752 1753 ------------------------------- 1754 -- Analyze_Renamed_Character -- 1755 ------------------------------- 1756 1757 procedure Analyze_Renamed_Character 1758 (N : Node_Id; 1759 New_S : Entity_Id; 1760 Is_Body : Boolean) 1761 is 1762 C : constant Node_Id := Name (N); 1763 1764 begin 1765 if Ekind (New_S) = E_Function then 1766 Resolve (C, Etype (New_S)); 1767 1768 if Is_Body then 1769 Check_Frozen_Renaming (N, New_S); 1770 end if; 1771 1772 else 1773 Error_Msg_N ("character literal can only be renamed as function", N); 1774 end if; 1775 end Analyze_Renamed_Character; 1776 1777 --------------------------------- 1778 -- Analyze_Renamed_Dereference -- 1779 --------------------------------- 1780 1781 procedure Analyze_Renamed_Dereference 1782 (N : Node_Id; 1783 New_S : Entity_Id; 1784 Is_Body : Boolean) 1785 is 1786 Nam : constant Node_Id := Name (N); 1787 P : constant Node_Id := Prefix (Nam); 1788 Typ : Entity_Id; 1789 Ind : Interp_Index; 1790 It : Interp; 1791 1792 begin 1793 if not Is_Overloaded (P) then 1794 if Ekind (Etype (Nam)) /= E_Subprogram_Type 1795 or else not Type_Conformant (Etype (Nam), New_S) 1796 then 1797 Error_Msg_N ("designated type does not match specification", P); 1798 else 1799 Resolve (P); 1800 end if; 1801 1802 return; 1803 1804 else 1805 Typ := Any_Type; 1806 Get_First_Interp (Nam, Ind, It); 1807 1808 while Present (It.Nam) loop 1809 1810 if Ekind (It.Nam) = E_Subprogram_Type 1811 and then Type_Conformant (It.Nam, New_S) 1812 then 1813 if Typ /= Any_Id then 1814 Error_Msg_N ("ambiguous renaming", P); 1815 return; 1816 else 1817 Typ := It.Nam; 1818 end if; 1819 end if; 1820 1821 Get_Next_Interp (Ind, It); 1822 end loop; 1823 1824 if Typ = Any_Type then 1825 Error_Msg_N ("designated type does not match specification", P); 1826 else 1827 Resolve (N, Typ); 1828 1829 if Is_Body then 1830 Check_Frozen_Renaming (N, New_S); 1831 end if; 1832 end if; 1833 end if; 1834 end Analyze_Renamed_Dereference; 1835 1836 --------------------------- 1837 -- Analyze_Renamed_Entry -- 1838 --------------------------- 1839 1840 procedure Analyze_Renamed_Entry 1841 (N : Node_Id; 1842 New_S : Entity_Id; 1843 Is_Body : Boolean) 1844 is 1845 Nam : constant Node_Id := Name (N); 1846 Sel : constant Node_Id := Selector_Name (Nam); 1847 Is_Actual : constant Boolean := Present (Corresponding_Formal_Spec (N)); 1848 Old_S : Entity_Id; 1849 1850 begin 1851 if Entity (Sel) = Any_Id then 1852 1853 -- Selector is undefined on prefix. Error emitted already 1854 1855 Set_Has_Completion (New_S); 1856 return; 1857 end if; 1858 1859 -- Otherwise find renamed entity and build body of New_S as a call to it 1860 1861 Old_S := Find_Renamed_Entity (N, Selector_Name (Nam), New_S); 1862 1863 if Old_S = Any_Id then 1864 Error_Msg_N ("no subprogram or entry matches specification", N); 1865 else 1866 if Is_Body then 1867 Check_Subtype_Conformant (New_S, Old_S, N); 1868 Generate_Reference (New_S, Defining_Entity (N), 'b'); 1869 Style.Check_Identifier (Defining_Entity (N), New_S); 1870 1871 else 1872 -- Only mode conformance required for a renaming_as_declaration 1873 1874 Check_Mode_Conformant (New_S, Old_S, N); 1875 end if; 1876 1877 Inherit_Renamed_Profile (New_S, Old_S); 1878 1879 -- The prefix can be an arbitrary expression that yields a task or 1880 -- protected object, so it must be resolved. 1881 1882 if Is_Access_Type (Etype (Prefix (Nam))) then 1883 Insert_Explicit_Dereference (Prefix (Nam)); 1884 end if; 1885 Resolve (Prefix (Nam), Scope (Old_S)); 1886 end if; 1887 1888 Set_Convention (New_S, Convention (Old_S)); 1889 Set_Has_Completion (New_S, Inside_A_Generic); 1890 1891 -- AI05-0225: If the renamed entity is a procedure or entry of a 1892 -- protected object, the target object must be a variable. 1893 1894 if Is_Protected_Type (Scope (Old_S)) 1895 and then Ekind (New_S) = E_Procedure 1896 and then not Is_Variable (Prefix (Nam)) 1897 then 1898 if Is_Actual then 1899 Error_Msg_N 1900 ("target object of protected operation used as actual for " 1901 & "formal procedure must be a variable", Nam); 1902 else 1903 Error_Msg_N 1904 ("target object of protected operation renamed as procedure, " 1905 & "must be a variable", Nam); 1906 end if; 1907 end if; 1908 1909 if Is_Body then 1910 Check_Frozen_Renaming (N, New_S); 1911 end if; 1912 end Analyze_Renamed_Entry; 1913 1914 ----------------------------------- 1915 -- Analyze_Renamed_Family_Member -- 1916 ----------------------------------- 1917 1918 procedure Analyze_Renamed_Family_Member 1919 (N : Node_Id; 1920 New_S : Entity_Id; 1921 Is_Body : Boolean) 1922 is 1923 Nam : constant Node_Id := Name (N); 1924 P : constant Node_Id := Prefix (Nam); 1925 Old_S : Entity_Id; 1926 1927 begin 1928 if (Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Entry_Family) 1929 or else (Nkind (P) = N_Selected_Component 1930 and then Ekind (Entity (Selector_Name (P))) = E_Entry_Family) 1931 then 1932 if Is_Entity_Name (P) then 1933 Old_S := Entity (P); 1934 else 1935 Old_S := Entity (Selector_Name (P)); 1936 end if; 1937 1938 if not Entity_Matches_Spec (Old_S, New_S) then 1939 Error_Msg_N ("entry family does not match specification", N); 1940 1941 elsif Is_Body then 1942 Check_Subtype_Conformant (New_S, Old_S, N); 1943 Generate_Reference (New_S, Defining_Entity (N), 'b'); 1944 Style.Check_Identifier (Defining_Entity (N), New_S); 1945 end if; 1946 1947 else 1948 Error_Msg_N ("no entry family matches specification", N); 1949 end if; 1950 1951 Set_Has_Completion (New_S, Inside_A_Generic); 1952 1953 if Is_Body then 1954 Check_Frozen_Renaming (N, New_S); 1955 end if; 1956 end Analyze_Renamed_Family_Member; 1957 1958 ----------------------------------------- 1959 -- Analyze_Renamed_Primitive_Operation -- 1960 ----------------------------------------- 1961 1962 procedure Analyze_Renamed_Primitive_Operation 1963 (N : Node_Id; 1964 New_S : Entity_Id; 1965 Is_Body : Boolean) 1966 is 1967 Old_S : Entity_Id; 1968 Nam : Entity_Id; 1969 1970 function Conforms 1971 (Subp : Entity_Id; 1972 Ctyp : Conformance_Type) return Boolean; 1973 -- Verify that the signatures of the renamed entity and the new entity 1974 -- match. The first formal of the renamed entity is skipped because it 1975 -- is the target object in any subsequent call. 1976 1977 -------------- 1978 -- Conforms -- 1979 -------------- 1980 1981 function Conforms 1982 (Subp : Entity_Id; 1983 Ctyp : Conformance_Type) return Boolean 1984 is 1985 Old_F : Entity_Id; 1986 New_F : Entity_Id; 1987 1988 begin 1989 if Ekind (Subp) /= Ekind (New_S) then 1990 return False; 1991 end if; 1992 1993 Old_F := Next_Formal (First_Formal (Subp)); 1994 New_F := First_Formal (New_S); 1995 while Present (Old_F) and then Present (New_F) loop 1996 if not Conforming_Types (Etype (Old_F), Etype (New_F), Ctyp) then 1997 return False; 1998 end if; 1999 2000 if Ctyp >= Mode_Conformant 2001 and then Ekind (Old_F) /= Ekind (New_F) 2002 then 2003 return False; 2004 end if; 2005 2006 Next_Formal (New_F); 2007 Next_Formal (Old_F); 2008 end loop; 2009 2010 return True; 2011 end Conforms; 2012 2013 -- Start of processing for Analyze_Renamed_Primitive_Operation 2014 2015 begin 2016 if not Is_Overloaded (Selector_Name (Name (N))) then 2017 Old_S := Entity (Selector_Name (Name (N))); 2018 2019 if not Conforms (Old_S, Type_Conformant) then 2020 Old_S := Any_Id; 2021 end if; 2022 2023 else 2024 -- Find the operation that matches the given signature 2025 2026 declare 2027 It : Interp; 2028 Ind : Interp_Index; 2029 2030 begin 2031 Old_S := Any_Id; 2032 Get_First_Interp (Selector_Name (Name (N)), Ind, It); 2033 2034 while Present (It.Nam) loop 2035 if Conforms (It.Nam, Type_Conformant) then 2036 Old_S := It.Nam; 2037 end if; 2038 2039 Get_Next_Interp (Ind, It); 2040 end loop; 2041 end; 2042 end if; 2043 2044 if Old_S = Any_Id then 2045 Error_Msg_N ("no subprogram or entry matches specification", N); 2046 2047 else 2048 if Is_Body then 2049 if not Conforms (Old_S, Subtype_Conformant) then 2050 Error_Msg_N ("subtype conformance error in renaming", N); 2051 end if; 2052 2053 Generate_Reference (New_S, Defining_Entity (N), 'b'); 2054 Style.Check_Identifier (Defining_Entity (N), New_S); 2055 2056 else 2057 -- Only mode conformance required for a renaming_as_declaration 2058 2059 if not Conforms (Old_S, Mode_Conformant) then 2060 Error_Msg_N ("mode conformance error in renaming", N); 2061 end if; 2062 2063 -- AI12-0204: The prefix of a prefixed view that is renamed or 2064 -- passed as a formal subprogram must be renamable as an object. 2065 2066 Nam := Prefix (Name (N)); 2067 2068 if Is_Object_Reference (Nam) then 2069 if Is_Dependent_Component_Of_Mutable_Object (Nam) then 2070 Error_Msg_N 2071 ("illegal renaming of discriminant-dependent component", 2072 Nam); 2073 end if; 2074 else 2075 Error_Msg_N ("expect object name in renaming", Nam); 2076 end if; 2077 2078 -- Enforce the rule given in (RM 6.3.1 (10.1/2)): a prefixed 2079 -- view of a subprogram is intrinsic, because the compiler has 2080 -- to generate a wrapper for any call to it. If the name in a 2081 -- subprogram renaming is a prefixed view, the entity is thus 2082 -- intrinsic, and 'Access cannot be applied to it. 2083 2084 Set_Convention (New_S, Convention_Intrinsic); 2085 end if; 2086 2087 -- Inherit_Renamed_Profile (New_S, Old_S); 2088 2089 -- The prefix can be an arbitrary expression that yields an 2090 -- object, so it must be resolved. 2091 2092 Resolve (Prefix (Name (N))); 2093 end if; 2094 end Analyze_Renamed_Primitive_Operation; 2095 2096 --------------------------------- 2097 -- Analyze_Subprogram_Renaming -- 2098 --------------------------------- 2099 2100 procedure Analyze_Subprogram_Renaming (N : Node_Id) is 2101 Formal_Spec : constant Entity_Id := Corresponding_Formal_Spec (N); 2102 Is_Actual : constant Boolean := Present (Formal_Spec); 2103 Nam : constant Node_Id := Name (N); 2104 Save_AV : constant Ada_Version_Type := Ada_Version; 2105 Save_AVP : constant Node_Id := Ada_Version_Pragma; 2106 Save_AV_Exp : constant Ada_Version_Type := Ada_Version_Explicit; 2107 Spec : constant Node_Id := Specification (N); 2108 2109 Old_S : Entity_Id := Empty; 2110 Rename_Spec : Entity_Id; 2111 2112 procedure Check_Null_Exclusion 2113 (Ren : Entity_Id; 2114 Sub : Entity_Id); 2115 -- Ada 2005 (AI-423): Given renaming Ren of subprogram Sub, check the 2116 -- following AI rules: 2117 -- 2118 -- If Ren denotes a generic formal object of a generic unit G, and the 2119 -- renaming (or instantiation containing the actual) occurs within the 2120 -- body of G or within the body of a generic unit declared within the 2121 -- declarative region of G, then the corresponding parameter of G 2122 -- shall have a null_exclusion; Otherwise the subtype of the Sub's 2123 -- formal parameter shall exclude null. 2124 -- 2125 -- Similarly for its return profile. 2126 2127 procedure Check_SPARK_Primitive_Operation (Subp_Id : Entity_Id); 2128 -- Ensure that a SPARK renaming denoted by its entity Subp_Id does not 2129 -- declare a primitive operation of a tagged type (SPARK RM 6.1.1(3)). 2130 2131 procedure Freeze_Actual_Profile; 2132 -- In Ada 2012, enforce the freezing rule concerning formal incomplete 2133 -- types: a callable entity freezes its profile, unless it has an 2134 -- incomplete untagged formal (RM 13.14(10.2/3)). 2135 2136 function Has_Class_Wide_Actual return Boolean; 2137 -- Ada 2012 (AI05-071, AI05-0131) and Ada 2022 (AI12-0165): True if N is 2138 -- the renaming for a defaulted formal subprogram where the actual for 2139 -- the controlling formal type is class-wide. 2140 2141 procedure Handle_Instance_With_Class_Wide_Type 2142 (Inst_Node : Node_Id; 2143 Ren_Id : Entity_Id; 2144 Wrapped_Prim : out Entity_Id; 2145 Wrap_Id : out Entity_Id); 2146 -- Ada 2012 (AI05-0071), Ada 2022 (AI12-0165): when the actual type 2147 -- of an instantiation is a class-wide type T'Class we may need to 2148 -- wrap a primitive operation of T; this routine looks for a suitable 2149 -- primitive to be wrapped and (if the wrapper is required) returns the 2150 -- Id of the wrapped primitive and the Id of the built wrapper. Ren_Id 2151 -- is the defining entity for the renamed subprogram specification. 2152 2153 function Original_Subprogram (Subp : Entity_Id) return Entity_Id; 2154 -- Find renamed entity when the declaration is a renaming_as_body and 2155 -- the renamed entity may itself be a renaming_as_body. Used to enforce 2156 -- rule that a renaming_as_body is illegal if the declaration occurs 2157 -- before the subprogram it completes is frozen, and renaming indirectly 2158 -- renames the subprogram itself.(Defect Report 8652/0027). 2159 2160 -------------------------- 2161 -- Check_Null_Exclusion -- 2162 -------------------------- 2163 2164 procedure Check_Null_Exclusion 2165 (Ren : Entity_Id; 2166 Sub : Entity_Id) 2167 is 2168 Ren_Formal : Entity_Id; 2169 Sub_Formal : Entity_Id; 2170 2171 function Null_Exclusion_Mismatch 2172 (Renaming : Entity_Id; Renamed : Entity_Id) return Boolean; 2173 -- Return True if there is a null exclusion mismatch between 2174 -- Renaming and Renamed, False otherwise. 2175 2176 ----------------------------- 2177 -- Null_Exclusion_Mismatch -- 2178 ----------------------------- 2179 2180 function Null_Exclusion_Mismatch 2181 (Renaming : Entity_Id; Renamed : Entity_Id) return Boolean is 2182 begin 2183 return Has_Null_Exclusion (Parent (Renaming)) 2184 and then 2185 not (Has_Null_Exclusion (Parent (Renamed)) 2186 or else (Can_Never_Be_Null (Etype (Renamed)) 2187 and then not 2188 (Is_Formal_Subprogram (Sub) 2189 and then In_Generic_Body (Current_Scope)))); 2190 end Null_Exclusion_Mismatch; 2191 2192 begin 2193 -- Parameter check 2194 2195 Ren_Formal := First_Formal (Ren); 2196 Sub_Formal := First_Formal (Sub); 2197 while Present (Ren_Formal) and then Present (Sub_Formal) loop 2198 if Null_Exclusion_Mismatch (Ren_Formal, Sub_Formal) then 2199 Error_Msg_Sloc := Sloc (Sub_Formal); 2200 Error_Msg_NE 2201 ("`NOT NULL` required for parameter &#", 2202 Ren_Formal, Sub_Formal); 2203 end if; 2204 2205 Next_Formal (Ren_Formal); 2206 Next_Formal (Sub_Formal); 2207 end loop; 2208 2209 -- Return profile check 2210 2211 if Nkind (Parent (Ren)) = N_Function_Specification 2212 and then Nkind (Parent (Sub)) = N_Function_Specification 2213 and then Null_Exclusion_Mismatch (Ren, Sub) 2214 then 2215 Error_Msg_Sloc := Sloc (Sub); 2216 Error_Msg_N ("return must specify `NOT NULL`#", Ren); 2217 end if; 2218 end Check_Null_Exclusion; 2219 2220 ------------------------------------- 2221 -- Check_SPARK_Primitive_Operation -- 2222 ------------------------------------- 2223 2224 procedure Check_SPARK_Primitive_Operation (Subp_Id : Entity_Id) is 2225 Prag : constant Node_Id := SPARK_Pragma (Subp_Id); 2226 Typ : Entity_Id; 2227 2228 begin 2229 -- Nothing to do when the subprogram is not subject to SPARK_Mode On 2230 -- because this check applies to SPARK code only. 2231 2232 if not (Present (Prag) 2233 and then Get_SPARK_Mode_From_Annotation (Prag) = On) 2234 then 2235 return; 2236 2237 -- Nothing to do when the subprogram is not a primitive operation 2238 2239 elsif not Is_Primitive (Subp_Id) then 2240 return; 2241 end if; 2242 2243 Typ := Find_Dispatching_Type (Subp_Id); 2244 2245 -- Nothing to do when the subprogram is a primitive operation of an 2246 -- untagged type. 2247 2248 if No (Typ) then 2249 return; 2250 end if; 2251 2252 -- At this point a renaming declaration introduces a new primitive 2253 -- operation for a tagged type. 2254 2255 Error_Msg_Node_2 := Typ; 2256 Error_Msg_NE 2257 ("subprogram renaming & cannot declare primitive for type & " 2258 & "(SPARK RM 6.1.1(3))", N, Subp_Id); 2259 end Check_SPARK_Primitive_Operation; 2260 2261 --------------------------- 2262 -- Freeze_Actual_Profile -- 2263 --------------------------- 2264 2265 procedure Freeze_Actual_Profile is 2266 F : Entity_Id; 2267 Has_Untagged_Inc : Boolean; 2268 Instantiation_Node : constant Node_Id := Parent (N); 2269 2270 begin 2271 if Ada_Version >= Ada_2012 then 2272 F := First_Formal (Formal_Spec); 2273 Has_Untagged_Inc := False; 2274 while Present (F) loop 2275 if Ekind (Etype (F)) = E_Incomplete_Type 2276 and then not Is_Tagged_Type (Etype (F)) 2277 then 2278 Has_Untagged_Inc := True; 2279 exit; 2280 end if; 2281 2282 Next_Formal (F); 2283 end loop; 2284 2285 if Ekind (Formal_Spec) = E_Function 2286 and then not Is_Tagged_Type (Etype (Formal_Spec)) 2287 then 2288 Has_Untagged_Inc := True; 2289 end if; 2290 2291 if not Has_Untagged_Inc then 2292 F := First_Formal (Old_S); 2293 while Present (F) loop 2294 Freeze_Before (Instantiation_Node, Etype (F)); 2295 2296 if Is_Incomplete_Or_Private_Type (Etype (F)) 2297 and then No (Underlying_Type (Etype (F))) 2298 then 2299 -- Exclude generic types, or types derived from them. 2300 -- They will be frozen in the enclosing instance. 2301 2302 if Is_Generic_Type (Etype (F)) 2303 or else Is_Generic_Type (Root_Type (Etype (F))) 2304 then 2305 null; 2306 2307 -- A limited view of a type declared elsewhere needs no 2308 -- freezing actions. 2309 2310 elsif From_Limited_With (Etype (F)) then 2311 null; 2312 2313 else 2314 Error_Msg_NE 2315 ("type& must be frozen before this point", 2316 Instantiation_Node, Etype (F)); 2317 end if; 2318 end if; 2319 2320 Next_Formal (F); 2321 end loop; 2322 end if; 2323 end if; 2324 end Freeze_Actual_Profile; 2325 2326 --------------------------- 2327 -- Has_Class_Wide_Actual -- 2328 --------------------------- 2329 2330 function Has_Class_Wide_Actual return Boolean is 2331 Formal : Entity_Id; 2332 Formal_Typ : Entity_Id; 2333 2334 begin 2335 if Is_Actual then 2336 Formal := First_Formal (Formal_Spec); 2337 while Present (Formal) loop 2338 Formal_Typ := Etype (Formal); 2339 2340 if Has_Unknown_Discriminants (Formal_Typ) 2341 and then not Is_Class_Wide_Type (Formal_Typ) 2342 and then Is_Class_Wide_Type (Get_Instance_Of (Formal_Typ)) 2343 then 2344 return True; 2345 end if; 2346 2347 Next_Formal (Formal); 2348 end loop; 2349 end if; 2350 2351 return False; 2352 end Has_Class_Wide_Actual; 2353 2354 ------------------------------------------ 2355 -- Handle_Instance_With_Class_Wide_Type -- 2356 ------------------------------------------ 2357 2358 procedure Handle_Instance_With_Class_Wide_Type 2359 (Inst_Node : Node_Id; 2360 Ren_Id : Entity_Id; 2361 Wrapped_Prim : out Entity_Id; 2362 Wrap_Id : out Entity_Id) 2363 is 2364 procedure Build_Class_Wide_Wrapper 2365 (Ren_Id : Entity_Id; 2366 Prim_Op : Entity_Id; 2367 Wrap_Id : out Entity_Id); 2368 -- Build a wrapper for the renaming Ren_Id of subprogram Prim_Op. 2369 2370 procedure Find_Suitable_Candidate 2371 (Prim_Op : out Entity_Id; 2372 Is_CW_Prim : out Boolean); 2373 -- Look for a suitable primitive to be wrapped (Prim_Op); Is_CW_Prim 2374 -- indicates that the found candidate is a class-wide primitive (to 2375 -- help the caller decide if the wrapper is required). 2376 2377 ------------------------------ 2378 -- Build_Class_Wide_Wrapper -- 2379 ------------------------------ 2380 2381 procedure Build_Class_Wide_Wrapper 2382 (Ren_Id : Entity_Id; 2383 Prim_Op : Entity_Id; 2384 Wrap_Id : out Entity_Id) 2385 is 2386 Loc : constant Source_Ptr := Sloc (N); 2387 2388 function Build_Call 2389 (Subp_Id : Entity_Id; 2390 Params : List_Id) return Node_Id; 2391 -- Create a dispatching call to invoke routine Subp_Id with 2392 -- actuals built from the parameter specifications of list Params. 2393 2394 function Build_Expr_Fun_Call 2395 (Subp_Id : Entity_Id; 2396 Params : List_Id) return Node_Id; 2397 -- Create a dispatching call to invoke function Subp_Id with 2398 -- actuals built from the parameter specifications of list Params. 2399 -- Directly return the call, so that it can be used inside an 2400 -- expression function. This is a requirement of GNATprove mode. 2401 2402 function Build_Spec (Subp_Id : Entity_Id) return Node_Id; 2403 -- Create a subprogram specification based on the subprogram 2404 -- profile of Subp_Id. 2405 2406 ---------------- 2407 -- Build_Call -- 2408 ---------------- 2409 2410 function Build_Call 2411 (Subp_Id : Entity_Id; 2412 Params : List_Id) return Node_Id 2413 is 2414 Actuals : constant List_Id := New_List; 2415 Call_Ref : constant Node_Id := New_Occurrence_Of (Subp_Id, Loc); 2416 Formal : Node_Id; 2417 2418 begin 2419 -- Build the actual parameters of the call 2420 2421 Formal := First (Params); 2422 while Present (Formal) loop 2423 Append_To (Actuals, 2424 Make_Identifier (Loc, 2425 Chars (Defining_Identifier (Formal)))); 2426 Next (Formal); 2427 end loop; 2428 2429 -- Generate: 2430 -- return Subp_Id (Actuals); 2431 2432 if Ekind (Subp_Id) in E_Function | E_Operator then 2433 return 2434 Make_Simple_Return_Statement (Loc, 2435 Expression => 2436 Make_Function_Call (Loc, 2437 Name => Call_Ref, 2438 Parameter_Associations => Actuals)); 2439 2440 -- Generate: 2441 -- Subp_Id (Actuals); 2442 2443 else 2444 return 2445 Make_Procedure_Call_Statement (Loc, 2446 Name => Call_Ref, 2447 Parameter_Associations => Actuals); 2448 end if; 2449 end Build_Call; 2450 2451 ------------------------- 2452 -- Build_Expr_Fun_Call -- 2453 ------------------------- 2454 2455 function Build_Expr_Fun_Call 2456 (Subp_Id : Entity_Id; 2457 Params : List_Id) return Node_Id 2458 is 2459 Actuals : constant List_Id := New_List; 2460 Call_Ref : constant Node_Id := New_Occurrence_Of (Subp_Id, Loc); 2461 Formal : Node_Id; 2462 2463 begin 2464 pragma Assert (Ekind (Subp_Id) in E_Function | E_Operator); 2465 2466 -- Build the actual parameters of the call 2467 2468 Formal := First (Params); 2469 while Present (Formal) loop 2470 Append_To (Actuals, 2471 Make_Identifier (Loc, 2472 Chars (Defining_Identifier (Formal)))); 2473 Next (Formal); 2474 end loop; 2475 2476 -- Generate: 2477 -- Subp_Id (Actuals); 2478 2479 return 2480 Make_Function_Call (Loc, 2481 Name => Call_Ref, 2482 Parameter_Associations => Actuals); 2483 end Build_Expr_Fun_Call; 2484 2485 ---------------- 2486 -- Build_Spec -- 2487 ---------------- 2488 2489 function Build_Spec (Subp_Id : Entity_Id) return Node_Id is 2490 Params : constant List_Id := Copy_Parameter_List (Subp_Id); 2491 Spec_Id : constant Entity_Id := 2492 Make_Defining_Identifier (Loc, 2493 New_External_Name (Chars (Subp_Id), 'R')); 2494 2495 begin 2496 if Ekind (Formal_Spec) = E_Procedure then 2497 return 2498 Make_Procedure_Specification (Loc, 2499 Defining_Unit_Name => Spec_Id, 2500 Parameter_Specifications => Params); 2501 else 2502 return 2503 Make_Function_Specification (Loc, 2504 Defining_Unit_Name => Spec_Id, 2505 Parameter_Specifications => Params, 2506 Result_Definition => 2507 New_Copy_Tree (Result_Definition (Spec))); 2508 end if; 2509 end Build_Spec; 2510 2511 -- Local variables 2512 2513 Body_Decl : Node_Id; 2514 Spec_Decl : Node_Id; 2515 New_Spec : Node_Id; 2516 2517 -- Start of processing for Build_Class_Wide_Wrapper 2518 2519 begin 2520 pragma Assert (not Error_Posted (Nam)); 2521 2522 -- Step 1: Create the declaration and the body of the wrapper, 2523 -- insert all the pieces into the tree. 2524 2525 -- In GNATprove mode, create a function wrapper in the form of an 2526 -- expression function, so that an implicit postcondition relating 2527 -- the result of calling the wrapper function and the result of 2528 -- the dispatching call to the wrapped function is known during 2529 -- proof. 2530 2531 if GNATprove_Mode 2532 and then Ekind (Ren_Id) in E_Function | E_Operator 2533 then 2534 New_Spec := Build_Spec (Ren_Id); 2535 Body_Decl := 2536 Make_Expression_Function (Loc, 2537 Specification => New_Spec, 2538 Expression => 2539 Build_Expr_Fun_Call 2540 (Subp_Id => Prim_Op, 2541 Params => Parameter_Specifications (New_Spec))); 2542 2543 Wrap_Id := Defining_Entity (Body_Decl); 2544 2545 -- Otherwise, create separate spec and body for the subprogram 2546 2547 else 2548 Spec_Decl := 2549 Make_Subprogram_Declaration (Loc, 2550 Specification => Build_Spec (Ren_Id)); 2551 Insert_Before_And_Analyze (N, Spec_Decl); 2552 2553 Wrap_Id := Defining_Entity (Spec_Decl); 2554 2555 Body_Decl := 2556 Make_Subprogram_Body (Loc, 2557 Specification => Build_Spec (Ren_Id), 2558 Declarations => New_List, 2559 Handled_Statement_Sequence => 2560 Make_Handled_Sequence_Of_Statements (Loc, 2561 Statements => New_List ( 2562 Build_Call 2563 (Subp_Id => Prim_Op, 2564 Params => 2565 Parameter_Specifications 2566 (Specification (Spec_Decl)))))); 2567 2568 Set_Corresponding_Body (Spec_Decl, Defining_Entity (Body_Decl)); 2569 end if; 2570 2571 Set_Is_Class_Wide_Wrapper (Wrap_Id); 2572 2573 -- If the operator carries an Eliminated pragma, indicate that 2574 -- the wrapper is also to be eliminated, to prevent spurious 2575 -- errors when using gnatelim on programs that include box- 2576 -- defaulted initialization of equality operators. 2577 2578 Set_Is_Eliminated (Wrap_Id, Is_Eliminated (Prim_Op)); 2579 2580 -- In GNATprove mode, insert the body in the tree for analysis 2581 2582 if GNATprove_Mode then 2583 Insert_Before_And_Analyze (N, Body_Decl); 2584 end if; 2585 2586 -- The generated body does not freeze and must be analyzed when 2587 -- the class-wide wrapper is frozen. The body is only needed if 2588 -- expansion is enabled. 2589 2590 if Expander_Active then 2591 Append_Freeze_Action (Wrap_Id, Body_Decl); 2592 end if; 2593 2594 -- Step 2: The subprogram renaming aliases the wrapper 2595 2596 Rewrite (Name (N), New_Occurrence_Of (Wrap_Id, Loc)); 2597 end Build_Class_Wide_Wrapper; 2598 2599 ----------------------------- 2600 -- Find_Suitable_Candidate -- 2601 ----------------------------- 2602 2603 procedure Find_Suitable_Candidate 2604 (Prim_Op : out Entity_Id; 2605 Is_CW_Prim : out Boolean) 2606 is 2607 Loc : constant Source_Ptr := Sloc (N); 2608 2609 function Find_Primitive (Typ : Entity_Id) return Entity_Id; 2610 -- Find a primitive subprogram of type Typ which matches the 2611 -- profile of the renaming declaration. 2612 2613 procedure Interpretation_Error (Subp_Id : Entity_Id); 2614 -- Emit a continuation error message suggesting subprogram Subp_Id 2615 -- as a possible interpretation. 2616 2617 function Is_Intrinsic_Equality 2618 (Subp_Id : Entity_Id) return Boolean; 2619 -- Determine whether subprogram Subp_Id denotes the intrinsic "=" 2620 -- operator. 2621 2622 function Is_Suitable_Candidate 2623 (Subp_Id : Entity_Id) return Boolean; 2624 -- Determine whether subprogram Subp_Id is a suitable candidate 2625 -- for the role of a wrapped subprogram. 2626 2627 -------------------- 2628 -- Find_Primitive -- 2629 -------------------- 2630 2631 function Find_Primitive (Typ : Entity_Id) return Entity_Id is 2632 procedure Replace_Parameter_Types (Spec : Node_Id); 2633 -- Given a specification Spec, replace all class-wide parameter 2634 -- types with reference to type Typ. 2635 2636 ----------------------------- 2637 -- Replace_Parameter_Types -- 2638 ----------------------------- 2639 2640 procedure Replace_Parameter_Types (Spec : Node_Id) is 2641 Formal : Node_Id; 2642 Formal_Id : Entity_Id; 2643 Formal_Typ : Node_Id; 2644 2645 begin 2646 Formal := First (Parameter_Specifications (Spec)); 2647 while Present (Formal) loop 2648 Formal_Id := Defining_Identifier (Formal); 2649 Formal_Typ := Parameter_Type (Formal); 2650 2651 -- Create a new entity for each class-wide formal to 2652 -- prevent aliasing with the original renaming. Replace 2653 -- the type of such a parameter with the candidate type. 2654 2655 if Nkind (Formal_Typ) = N_Identifier 2656 and then Is_Class_Wide_Type (Etype (Formal_Typ)) 2657 then 2658 Set_Defining_Identifier (Formal, 2659 Make_Defining_Identifier (Loc, Chars (Formal_Id))); 2660 2661 Set_Parameter_Type (Formal, 2662 New_Occurrence_Of (Typ, Loc)); 2663 end if; 2664 2665 Next (Formal); 2666 end loop; 2667 end Replace_Parameter_Types; 2668 2669 -- Local variables 2670 2671 Alt_Ren : constant Node_Id := New_Copy_Tree (N); 2672 Alt_Nam : constant Node_Id := Name (Alt_Ren); 2673 Alt_Spec : constant Node_Id := Specification (Alt_Ren); 2674 Subp_Id : Entity_Id; 2675 2676 -- Start of processing for Find_Primitive 2677 2678 begin 2679 -- Each attempt to find a suitable primitive of a particular 2680 -- type operates on its own copy of the original renaming. 2681 -- As a result the original renaming is kept decoration and 2682 -- side-effect free. 2683 2684 -- Inherit the overloaded status of the renamed subprogram name 2685 2686 if Is_Overloaded (Nam) then 2687 Set_Is_Overloaded (Alt_Nam); 2688 Save_Interps (Nam, Alt_Nam); 2689 end if; 2690 2691 -- The copied renaming is hidden from visibility to prevent the 2692 -- pollution of the enclosing context. 2693 2694 Set_Defining_Unit_Name (Alt_Spec, Make_Temporary (Loc, 'R')); 2695 2696 -- The types of all class-wide parameters must be changed to 2697 -- the candidate type. 2698 2699 Replace_Parameter_Types (Alt_Spec); 2700 2701 -- Try to find a suitable primitive that matches the altered 2702 -- profile of the renaming specification. 2703 2704 Subp_Id := 2705 Find_Renamed_Entity 2706 (N => Alt_Ren, 2707 Nam => Name (Alt_Ren), 2708 New_S => Analyze_Subprogram_Specification (Alt_Spec), 2709 Is_Actual => Is_Actual); 2710 2711 -- Do not return Any_Id if the resolution of the altered 2712 -- profile failed as this complicates further checks on 2713 -- the caller side; return Empty instead. 2714 2715 if Subp_Id = Any_Id then 2716 return Empty; 2717 else 2718 return Subp_Id; 2719 end if; 2720 end Find_Primitive; 2721 2722 -------------------------- 2723 -- Interpretation_Error -- 2724 -------------------------- 2725 2726 procedure Interpretation_Error (Subp_Id : Entity_Id) is 2727 begin 2728 Error_Msg_Sloc := Sloc (Subp_Id); 2729 2730 if Is_Internal (Subp_Id) then 2731 Error_Msg_NE 2732 ("\\possible interpretation: predefined & #", 2733 Spec, Formal_Spec); 2734 else 2735 Error_Msg_NE 2736 ("\\possible interpretation: & defined #", 2737 Spec, Formal_Spec); 2738 end if; 2739 end Interpretation_Error; 2740 2741 --------------------------- 2742 -- Is_Intrinsic_Equality -- 2743 --------------------------- 2744 2745 function Is_Intrinsic_Equality (Subp_Id : Entity_Id) return Boolean 2746 is 2747 begin 2748 return 2749 Ekind (Subp_Id) = E_Operator 2750 and then Chars (Subp_Id) = Name_Op_Eq 2751 and then Is_Intrinsic_Subprogram (Subp_Id); 2752 end Is_Intrinsic_Equality; 2753 2754 --------------------------- 2755 -- Is_Suitable_Candidate -- 2756 --------------------------- 2757 2758 function Is_Suitable_Candidate (Subp_Id : Entity_Id) return Boolean 2759 is 2760 begin 2761 if No (Subp_Id) then 2762 return False; 2763 2764 -- An intrinsic subprogram is never a good candidate. This 2765 -- is an indication of a missing primitive, either defined 2766 -- directly or inherited from a parent tagged type. 2767 2768 elsif Is_Intrinsic_Subprogram (Subp_Id) then 2769 return False; 2770 2771 else 2772 return True; 2773 end if; 2774 end Is_Suitable_Candidate; 2775 2776 -- Local variables 2777 2778 Actual_Typ : Entity_Id := Empty; 2779 -- The actual class-wide type for Formal_Typ 2780 2781 CW_Prim_OK : Boolean; 2782 CW_Prim_Op : Entity_Id; 2783 -- The class-wide subprogram (if available) that corresponds to 2784 -- the renamed generic formal subprogram. 2785 2786 Formal_Typ : Entity_Id := Empty; 2787 -- The generic formal type with unknown discriminants 2788 2789 Root_Prim_OK : Boolean; 2790 Root_Prim_Op : Entity_Id; 2791 -- The root type primitive (if available) that corresponds to the 2792 -- renamed generic formal subprogram. 2793 2794 Root_Typ : Entity_Id := Empty; 2795 -- The root type of Actual_Typ 2796 2797 Formal : Node_Id; 2798 2799 -- Start of processing for Find_Suitable_Candidate 2800 2801 begin 2802 pragma Assert (not Error_Posted (Nam)); 2803 2804 Prim_Op := Empty; 2805 Is_CW_Prim := False; 2806 2807 -- Analyze the renamed name, but do not resolve it. The resolution 2808 -- is completed once a suitable subprogram is found. 2809 2810 Analyze (Nam); 2811 2812 -- When the renamed name denotes the intrinsic operator equals, 2813 -- the name must be treated as overloaded. This allows for a 2814 -- potential match against the root type's predefined equality 2815 -- function. 2816 2817 if Is_Intrinsic_Equality (Entity (Nam)) then 2818 Set_Is_Overloaded (Nam); 2819 Collect_Interps (Nam); 2820 end if; 2821 2822 -- Step 1: Find the generic formal type and its corresponding 2823 -- class-wide actual type from the renamed generic formal 2824 -- subprogram. 2825 2826 Formal := First_Formal (Formal_Spec); 2827 while Present (Formal) loop 2828 if Has_Unknown_Discriminants (Etype (Formal)) 2829 and then not Is_Class_Wide_Type (Etype (Formal)) 2830 and then Is_Class_Wide_Type (Get_Instance_Of (Etype (Formal))) 2831 then 2832 Formal_Typ := Etype (Formal); 2833 Actual_Typ := Base_Type (Get_Instance_Of (Formal_Typ)); 2834 Root_Typ := Root_Type (Actual_Typ); 2835 exit; 2836 end if; 2837 2838 Next_Formal (Formal); 2839 end loop; 2840 2841 -- The specification of the generic formal subprogram should 2842 -- always contain a formal type with unknown discriminants whose 2843 -- actual is a class-wide type; otherwise this indicates a failure 2844 -- in function Has_Class_Wide_Actual. 2845 2846 pragma Assert (Present (Formal_Typ)); 2847 2848 -- Step 2: Find the proper class-wide subprogram or primitive 2849 -- that corresponds to the renamed generic formal subprogram. 2850 2851 CW_Prim_Op := Find_Primitive (Actual_Typ); 2852 CW_Prim_OK := Is_Suitable_Candidate (CW_Prim_Op); 2853 Root_Prim_Op := Find_Primitive (Root_Typ); 2854 Root_Prim_OK := Is_Suitable_Candidate (Root_Prim_Op); 2855 2856 -- The class-wide actual type has two subprograms that correspond 2857 -- to the renamed generic formal subprogram: 2858 2859 -- with procedure Prim_Op (Param : Formal_Typ); 2860 2861 -- procedure Prim_Op (Param : Actual_Typ); -- may be inherited 2862 -- procedure Prim_Op (Param : Actual_Typ'Class); 2863 2864 -- Even though the declaration of the two subprograms is legal, a 2865 -- call to either one is ambiguous and therefore illegal. 2866 2867 if CW_Prim_OK and Root_Prim_OK then 2868 2869 -- A user-defined primitive has precedence over a predefined 2870 -- one. 2871 2872 if Is_Internal (CW_Prim_Op) 2873 and then not Is_Internal (Root_Prim_Op) 2874 then 2875 Prim_Op := Root_Prim_Op; 2876 2877 elsif Is_Internal (Root_Prim_Op) 2878 and then not Is_Internal (CW_Prim_Op) 2879 then 2880 Prim_Op := CW_Prim_Op; 2881 Is_CW_Prim := True; 2882 2883 elsif CW_Prim_Op = Root_Prim_Op then 2884 Prim_Op := Root_Prim_Op; 2885 2886 -- The two subprograms are legal but the class-wide subprogram 2887 -- is a class-wide wrapper built for a previous instantiation; 2888 -- the wrapper has precedence. 2889 2890 elsif Present (Alias (CW_Prim_Op)) 2891 and then Is_Class_Wide_Wrapper (Ultimate_Alias (CW_Prim_Op)) 2892 then 2893 Prim_Op := CW_Prim_Op; 2894 Is_CW_Prim := True; 2895 2896 -- Otherwise both candidate subprograms are user-defined and 2897 -- ambiguous. 2898 2899 else 2900 Error_Msg_NE 2901 ("ambiguous actual for generic subprogram &", 2902 Spec, Formal_Spec); 2903 Interpretation_Error (Root_Prim_Op); 2904 Interpretation_Error (CW_Prim_Op); 2905 return; 2906 end if; 2907 2908 elsif CW_Prim_OK and not Root_Prim_OK then 2909 Prim_Op := CW_Prim_Op; 2910 Is_CW_Prim := True; 2911 2912 elsif not CW_Prim_OK and Root_Prim_OK then 2913 Prim_Op := Root_Prim_Op; 2914 2915 -- An intrinsic equality may act as a suitable candidate in the 2916 -- case of a null type extension where the parent's equality 2917 -- is hidden. A call to an intrinsic equality is expanded as 2918 -- dispatching. 2919 2920 elsif Present (Root_Prim_Op) 2921 and then Is_Intrinsic_Equality (Root_Prim_Op) 2922 then 2923 Prim_Op := Root_Prim_Op; 2924 2925 -- Otherwise there are no candidate subprograms. Let the caller 2926 -- diagnose the error. 2927 2928 else 2929 return; 2930 end if; 2931 2932 -- At this point resolution has taken place and the name is no 2933 -- longer overloaded. Mark the primitive as referenced. 2934 2935 Set_Is_Overloaded (Name (N), False); 2936 Set_Referenced (Prim_Op); 2937 end Find_Suitable_Candidate; 2938 2939 -- Local variables 2940 2941 Is_CW_Prim : Boolean; 2942 2943 -- Start of processing for Handle_Instance_With_Class_Wide_Type 2944 2945 begin 2946 Wrapped_Prim := Empty; 2947 Wrap_Id := Empty; 2948 2949 -- Ada 2012 (AI05-0071): A generic/instance scenario involving a 2950 -- formal type with unknown discriminants and a generic primitive 2951 -- operation of the said type with a box require special processing 2952 -- when the actual is a class-wide type: 2953 -- 2954 -- generic 2955 -- type Formal_Typ (<>) is private; 2956 -- with procedure Prim_Op (Param : Formal_Typ) is <>; 2957 -- package Gen is ... 2958 -- 2959 -- package Inst is new Gen (Actual_Typ'Class); 2960 -- 2961 -- In this case the general renaming mechanism used in the prologue 2962 -- of an instance no longer applies: 2963 -- 2964 -- procedure Prim_Op (Param : Formal_Typ) renames Prim_Op; 2965 -- 2966 -- The above is replaced the following wrapper/renaming combination: 2967 -- 2968 -- procedure Wrapper (Param : Formal_Typ) is -- wrapper 2969 -- begin 2970 -- Prim_Op (Param); -- primitive 2971 -- end Wrapper; 2972 -- 2973 -- procedure Prim_Op (Param : Formal_Typ) renames Wrapper; 2974 -- 2975 -- This transformation applies only if there is no explicit visible 2976 -- class-wide operation at the point of the instantiation. Ren_Id is 2977 -- the entity of the renaming declaration. When the transformation 2978 -- applies, Wrapped_Prim is the entity of the wrapped primitive. 2979 2980 if Box_Present (Inst_Node) then 2981 Find_Suitable_Candidate 2982 (Prim_Op => Wrapped_Prim, 2983 Is_CW_Prim => Is_CW_Prim); 2984 2985 if Present (Wrapped_Prim) then 2986 if not Is_CW_Prim then 2987 Build_Class_Wide_Wrapper (Ren_Id, Wrapped_Prim, Wrap_Id); 2988 2989 -- Small optimization: When the candidate is a class-wide 2990 -- subprogram we don't build the wrapper; we modify the 2991 -- renaming declaration to directly map the actual to the 2992 -- generic formal and discard the candidate. 2993 2994 else 2995 Rewrite (Nam, New_Occurrence_Of (Wrapped_Prim, Sloc (N))); 2996 Wrapped_Prim := Empty; 2997 end if; 2998 end if; 2999 3000 -- Ada 2022 (AI12-0165, RM 12.6(8.5/3)): The actual subprogram for a 3001 -- formal_abstract_subprogram_declaration shall be: 3002 -- a) a dispatching operation of the controlling type; or 3003 -- b) if the controlling type is a formal type, and the actual 3004 -- type corresponding to that formal type is a specific type T, 3005 -- a dispatching operation of type T; or 3006 -- c) if the controlling type is a formal type, and the actual 3007 -- type is a class-wide type T'Class, an implicitly declared 3008 -- subprogram corresponding to a primitive operation of type T. 3009 3010 elsif Nkind (Inst_Node) = N_Formal_Abstract_Subprogram_Declaration 3011 and then Is_Entity_Name (Nam) 3012 then 3013 Find_Suitable_Candidate 3014 (Prim_Op => Wrapped_Prim, 3015 Is_CW_Prim => Is_CW_Prim); 3016 3017 if Present (Wrapped_Prim) then 3018 3019 -- Cases (a) and (b); see previous description. 3020 3021 if not Is_CW_Prim then 3022 Build_Class_Wide_Wrapper (Ren_Id, Wrapped_Prim, Wrap_Id); 3023 3024 -- Case (c); see previous description. 3025 3026 -- Implicit operations of T'Class for subtype declarations 3027 -- are built by Derive_Subprogram, and their Alias attribute 3028 -- references the primitive operation of T. 3029 3030 elsif not Comes_From_Source (Wrapped_Prim) 3031 and then Nkind (Parent (Wrapped_Prim)) = N_Subtype_Declaration 3032 and then Present (Alias (Wrapped_Prim)) 3033 then 3034 -- We don't need to build the wrapper; we modify the 3035 -- renaming declaration to directly map the actual to 3036 -- the generic formal and discard the candidate. 3037 3038 Rewrite (Nam, 3039 New_Occurrence_Of (Alias (Wrapped_Prim), Sloc (N))); 3040 Wrapped_Prim := Empty; 3041 3042 -- Legality rules do not apply; discard the candidate. 3043 3044 else 3045 Wrapped_Prim := Empty; 3046 end if; 3047 end if; 3048 end if; 3049 end Handle_Instance_With_Class_Wide_Type; 3050 3051 ------------------------- 3052 -- Original_Subprogram -- 3053 ------------------------- 3054 3055 function Original_Subprogram (Subp : Entity_Id) return Entity_Id is 3056 Orig_Decl : Node_Id; 3057 Orig_Subp : Entity_Id; 3058 3059 begin 3060 -- First case: renamed entity is itself a renaming 3061 3062 if Present (Alias (Subp)) then 3063 return Alias (Subp); 3064 3065 elsif Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration 3066 and then Present (Corresponding_Body (Unit_Declaration_Node (Subp))) 3067 then 3068 -- Check if renamed entity is a renaming_as_body 3069 3070 Orig_Decl := 3071 Unit_Declaration_Node 3072 (Corresponding_Body (Unit_Declaration_Node (Subp))); 3073 3074 if Nkind (Orig_Decl) = N_Subprogram_Renaming_Declaration then 3075 Orig_Subp := Entity (Name (Orig_Decl)); 3076 3077 if Orig_Subp = Rename_Spec then 3078 3079 -- Circularity detected 3080 3081 return Orig_Subp; 3082 3083 else 3084 return (Original_Subprogram (Orig_Subp)); 3085 end if; 3086 else 3087 return Subp; 3088 end if; 3089 else 3090 return Subp; 3091 end if; 3092 end Original_Subprogram; 3093 3094 -- Local variables 3095 3096 CW_Actual : constant Boolean := Has_Class_Wide_Actual; 3097 -- Ada 2012 (AI05-071, AI05-0131) and Ada 2022 (AI12-0165): True if the 3098 -- renaming is for a defaulted formal subprogram when the actual for a 3099 -- related formal type is class-wide. 3100 3101 Inst_Node : Node_Id := Empty; 3102 New_S : Entity_Id := Empty; 3103 Wrapped_Prim : Entity_Id := Empty; 3104 3105 -- Start of processing for Analyze_Subprogram_Renaming 3106 3107 begin 3108 -- We must test for the attribute renaming case before the Analyze 3109 -- call because otherwise Sem_Attr will complain that the attribute 3110 -- is missing an argument when it is analyzed. 3111 3112 if Nkind (Nam) = N_Attribute_Reference then 3113 3114 -- In the case of an abstract formal subprogram association, rewrite 3115 -- an actual given by a stream or Put_Image attribute as the name of 3116 -- the corresponding stream or Put_Image primitive of the type. 3117 3118 -- In a generic context the stream and Put_Image operations are not 3119 -- generated, and this must be treated as a normal attribute 3120 -- reference, to be expanded in subsequent instantiations. 3121 3122 if Is_Actual 3123 and then Is_Abstract_Subprogram (Formal_Spec) 3124 and then Expander_Active 3125 then 3126 declare 3127 Prefix_Type : constant Entity_Id := Entity (Prefix (Nam)); 3128 Prim : Entity_Id; 3129 3130 begin 3131 -- The class-wide forms of the stream and Put_Image attributes 3132 -- are not primitive dispatching operations (even though they 3133 -- internally dispatch). 3134 3135 if Is_Class_Wide_Type (Prefix_Type) then 3136 Error_Msg_N 3137 ("attribute must be a primitive dispatching operation", 3138 Nam); 3139 return; 3140 end if; 3141 3142 -- Retrieve the primitive subprogram associated with the 3143 -- attribute. This can only be a stream attribute, since those 3144 -- are the only ones that are dispatching (and the actual for 3145 -- an abstract formal subprogram must be dispatching 3146 -- operation). 3147 3148 case Attribute_Name (Nam) is 3149 when Name_Input => 3150 Prim := 3151 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Input); 3152 3153 when Name_Output => 3154 Prim := 3155 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Output); 3156 3157 when Name_Read => 3158 Prim := 3159 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Read); 3160 3161 when Name_Write => 3162 Prim := 3163 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Write); 3164 3165 when Name_Put_Image => 3166 Prim := 3167 Find_Optional_Prim_Op (Prefix_Type, TSS_Put_Image); 3168 3169 when others => 3170 Error_Msg_N 3171 ("attribute must be a primitive dispatching operation", 3172 Nam); 3173 return; 3174 end case; 3175 3176 -- If no stream operation was found, and the type is limited, 3177 -- the user should have defined one. This rule does not apply 3178 -- to Put_Image. 3179 3180 if No (Prim) 3181 and then Attribute_Name (Nam) /= Name_Put_Image 3182 then 3183 if Is_Limited_Type (Prefix_Type) then 3184 Error_Msg_NE 3185 ("stream operation not defined for type&", 3186 N, Prefix_Type); 3187 return; 3188 3189 -- Otherwise, compiler should have generated default 3190 3191 else 3192 raise Program_Error; 3193 end if; 3194 end if; 3195 3196 -- Rewrite the attribute into the name of its corresponding 3197 -- primitive dispatching subprogram. We can then proceed with 3198 -- the usual processing for subprogram renamings. 3199 3200 declare 3201 Prim_Name : constant Node_Id := 3202 Make_Identifier (Sloc (Nam), 3203 Chars => Chars (Prim)); 3204 begin 3205 Set_Entity (Prim_Name, Prim); 3206 Rewrite (Nam, Prim_Name); 3207 Analyze (Nam); 3208 end; 3209 end; 3210 3211 -- Normal processing for a renaming of an attribute 3212 3213 else 3214 Attribute_Renaming (N); 3215 return; 3216 end if; 3217 end if; 3218 3219 -- Check whether this declaration corresponds to the instantiation of a 3220 -- formal subprogram. 3221 3222 -- If this is an instantiation, the corresponding actual is frozen and 3223 -- error messages can be made more precise. If this is a default 3224 -- subprogram, the entity is already established in the generic, and is 3225 -- not retrieved by visibility. If it is a default with a box, the 3226 -- candidate interpretations, if any, have been collected when building 3227 -- the renaming declaration. If overloaded, the proper interpretation is 3228 -- determined in Find_Renamed_Entity. If the entity is an operator, 3229 -- Find_Renamed_Entity applies additional visibility checks. 3230 3231 if Is_Actual then 3232 Inst_Node := Unit_Declaration_Node (Formal_Spec); 3233 3234 -- Ada 2012 (AI05-0071) and Ada 2022 (AI12-0165): when the actual 3235 -- type is a class-wide type T'Class we may need to wrap a primitive 3236 -- operation of T. Search for the wrapped primitive and (if required) 3237 -- build a wrapper whose body consists of a dispatching call to the 3238 -- wrapped primitive of T, with its formal parameters as the actual 3239 -- parameters. 3240 3241 if CW_Actual and then 3242 3243 -- Ada 2012 (AI05-0071): Check whether the renaming is for a 3244 -- defaulted actual subprogram with a class-wide actual. 3245 3246 (Box_Present (Inst_Node) 3247 3248 or else 3249 3250 -- Ada 2022 (AI12-0165): Check whether the renaming is for a formal 3251 -- abstract subprogram declaration with a class-wide actual. 3252 3253 (Nkind (Inst_Node) = N_Formal_Abstract_Subprogram_Declaration 3254 and then Is_Entity_Name (Nam))) 3255 then 3256 New_S := Analyze_Subprogram_Specification (Spec); 3257 3258 -- Do not attempt to build the wrapper if the renaming is in error 3259 3260 if not Error_Posted (Nam) then 3261 Handle_Instance_With_Class_Wide_Type 3262 (Inst_Node => Inst_Node, 3263 Ren_Id => New_S, 3264 Wrapped_Prim => Wrapped_Prim, 3265 Wrap_Id => Old_S); 3266 3267 -- If several candidates were found, then we reported the 3268 -- ambiguity; stop processing the renaming declaration to 3269 -- avoid reporting further (spurious) errors. 3270 3271 if Error_Posted (Spec) then 3272 return; 3273 end if; 3274 3275 end if; 3276 end if; 3277 3278 if Present (Wrapped_Prim) then 3279 3280 -- When the wrapper is built, the subprogram renaming aliases 3281 -- the wrapper. 3282 3283 Analyze (Nam); 3284 3285 pragma Assert (Old_S = Entity (Nam) 3286 and then Is_Class_Wide_Wrapper (Old_S)); 3287 3288 -- The subprogram renaming declaration may become Ghost if it 3289 -- renames a wrapper of a Ghost entity. 3290 3291 Mark_Ghost_Renaming (N, Wrapped_Prim); 3292 3293 elsif Is_Entity_Name (Nam) 3294 and then Present (Entity (Nam)) 3295 and then not Comes_From_Source (Nam) 3296 and then not Is_Overloaded (Nam) 3297 then 3298 Old_S := Entity (Nam); 3299 3300 -- The subprogram renaming declaration may become Ghost if it 3301 -- renames a Ghost entity. 3302 3303 Mark_Ghost_Renaming (N, Old_S); 3304 3305 New_S := Analyze_Subprogram_Specification (Spec); 3306 3307 -- Operator case 3308 3309 if Ekind (Old_S) = E_Operator then 3310 3311 -- Box present 3312 3313 if Box_Present (Inst_Node) then 3314 Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual); 3315 3316 -- If there is an immediately visible homonym of the operator 3317 -- and the declaration has a default, this is worth a warning 3318 -- because the user probably did not intend to get the pre- 3319 -- defined operator, visible in the generic declaration. To 3320 -- find if there is an intended candidate, analyze the renaming 3321 -- again in the current context. 3322 3323 elsif Scope (Old_S) = Standard_Standard 3324 and then Present (Default_Name (Inst_Node)) 3325 then 3326 declare 3327 Decl : constant Node_Id := New_Copy_Tree (N); 3328 Hidden : Entity_Id; 3329 3330 begin 3331 Set_Entity (Name (Decl), Empty); 3332 Analyze (Name (Decl)); 3333 Hidden := 3334 Find_Renamed_Entity (Decl, Name (Decl), New_S, True); 3335 3336 if Present (Hidden) 3337 and then In_Open_Scopes (Scope (Hidden)) 3338 and then Is_Immediately_Visible (Hidden) 3339 and then Comes_From_Source (Hidden) 3340 and then Hidden /= Old_S 3341 then 3342 Error_Msg_Sloc := Sloc (Hidden); 3343 Error_Msg_N 3344 ("default subprogram is resolved in the generic " 3345 & "declaration (RM 12.6(17))??", N); 3346 Error_Msg_NE ("\and will not use & #??", N, Hidden); 3347 end if; 3348 end; 3349 end if; 3350 end if; 3351 3352 else 3353 Analyze (Nam); 3354 3355 -- The subprogram renaming declaration may become Ghost if it 3356 -- renames a Ghost entity. 3357 3358 if Is_Entity_Name (Nam) then 3359 Mark_Ghost_Renaming (N, Entity (Nam)); 3360 end if; 3361 3362 New_S := Analyze_Subprogram_Specification (Spec); 3363 end if; 3364 3365 else 3366 -- Renamed entity must be analyzed first, to avoid being hidden by 3367 -- new name (which might be the same in a generic instance). 3368 3369 Analyze (Nam); 3370 3371 -- The subprogram renaming declaration may become Ghost if it renames 3372 -- a Ghost entity. 3373 3374 if Is_Entity_Name (Nam) then 3375 Mark_Ghost_Renaming (N, Entity (Nam)); 3376 end if; 3377 3378 -- The renaming defines a new overloaded entity, which is analyzed 3379 -- like a subprogram declaration. 3380 3381 New_S := Analyze_Subprogram_Specification (Spec); 3382 end if; 3383 3384 if Current_Scope /= Standard_Standard then 3385 Set_Is_Pure (New_S, Is_Pure (Current_Scope)); 3386 end if; 3387 3388 -- Set SPARK mode from current context 3389 3390 Set_SPARK_Pragma (New_S, SPARK_Mode_Pragma); 3391 Set_SPARK_Pragma_Inherited (New_S); 3392 3393 Rename_Spec := Find_Corresponding_Spec (N); 3394 3395 -- Case of Renaming_As_Body 3396 3397 if Present (Rename_Spec) then 3398 Check_Previous_Null_Procedure (N, Rename_Spec); 3399 3400 -- Renaming declaration is the completion of the declaration of 3401 -- Rename_Spec. We build an actual body for it at the freezing point. 3402 3403 Set_Corresponding_Spec (N, Rename_Spec); 3404 3405 -- Deal with special case of stream functions of abstract types 3406 -- and interfaces. 3407 3408 if Nkind (Unit_Declaration_Node (Rename_Spec)) = 3409 N_Abstract_Subprogram_Declaration 3410 then 3411 -- Input stream functions are abstract if the object type is 3412 -- abstract. Similarly, all default stream functions for an 3413 -- interface type are abstract. However, these subprograms may 3414 -- receive explicit declarations in representation clauses, making 3415 -- the attribute subprograms usable as defaults in subsequent 3416 -- type extensions. 3417 -- In this case we rewrite the declaration to make the subprogram 3418 -- non-abstract. We remove the previous declaration, and insert 3419 -- the new one at the point of the renaming, to prevent premature 3420 -- access to unfrozen types. The new declaration reuses the 3421 -- specification of the previous one, and must not be analyzed. 3422 3423 pragma Assert 3424 (Is_Primitive (Entity (Nam)) 3425 and then 3426 Is_Abstract_Type (Find_Dispatching_Type (Entity (Nam)))); 3427 declare 3428 Old_Decl : constant Node_Id := 3429 Unit_Declaration_Node (Rename_Spec); 3430 New_Decl : constant Node_Id := 3431 Make_Subprogram_Declaration (Sloc (N), 3432 Specification => 3433 Relocate_Node (Specification (Old_Decl))); 3434 begin 3435 Remove (Old_Decl); 3436 Insert_After (N, New_Decl); 3437 Set_Is_Abstract_Subprogram (Rename_Spec, False); 3438 Set_Analyzed (New_Decl); 3439 end; 3440 end if; 3441 3442 Set_Corresponding_Body (Unit_Declaration_Node (Rename_Spec), New_S); 3443 3444 if Ada_Version = Ada_83 and then Comes_From_Source (N) then 3445 Error_Msg_N ("(Ada 83) renaming cannot serve as a body", N); 3446 end if; 3447 3448 Set_Convention (New_S, Convention (Rename_Spec)); 3449 Check_Fully_Conformant (New_S, Rename_Spec); 3450 Set_Public_Status (New_S); 3451 3452 if No_Return (Rename_Spec) 3453 and then not No_Return (Entity (Nam)) 3454 then 3455 Error_Msg_NE 3456 ("renamed subprogram & must be No_Return", N, Entity (Nam)); 3457 Error_Msg_N 3458 ("\since renaming subprogram is No_Return (RM 6.5.1(7/2))", N); 3459 end if; 3460 3461 -- The specification does not introduce new formals, but only 3462 -- repeats the formals of the original subprogram declaration. 3463 -- For cross-reference purposes, and for refactoring tools, we 3464 -- treat the formals of the renaming declaration as body formals. 3465 3466 Reference_Body_Formals (Rename_Spec, New_S); 3467 3468 -- Indicate that the entity in the declaration functions like the 3469 -- corresponding body, and is not a new entity. The body will be 3470 -- constructed later at the freeze point, so indicate that the 3471 -- completion has not been seen yet. 3472 3473 Reinit_Field_To_Zero (New_S, F_Has_Out_Or_In_Out_Parameter); 3474 Reinit_Field_To_Zero (New_S, F_Needs_No_Actuals, 3475 Old_Ekind => (E_Function | E_Procedure => True, others => False)); 3476 Mutate_Ekind (New_S, E_Subprogram_Body); 3477 New_S := Rename_Spec; 3478 Set_Has_Completion (Rename_Spec, False); 3479 3480 -- Ada 2005: check overriding indicator 3481 3482 if Present (Overridden_Operation (Rename_Spec)) then 3483 if Must_Not_Override (Specification (N)) then 3484 Error_Msg_NE 3485 ("subprogram& overrides inherited operation", 3486 N, Rename_Spec); 3487 3488 elsif Style_Check 3489 and then not Must_Override (Specification (N)) 3490 then 3491 Style.Missing_Overriding (N, Rename_Spec); 3492 end if; 3493 3494 elsif Must_Override (Specification (N)) 3495 and then not Can_Override_Operator (Rename_Spec) 3496 then 3497 Error_Msg_NE ("subprogram& is not overriding", N, Rename_Spec); 3498 end if; 3499 3500 -- AI12-0132: a renames-as-body freezes the expression of any 3501 -- expression function that it renames. 3502 3503 if Is_Entity_Name (Nam) 3504 and then Is_Expression_Function (Entity (Nam)) 3505 and then not Inside_A_Generic 3506 then 3507 Freeze_Expr_Types 3508 (Def_Id => Entity (Nam), 3509 Typ => Etype (Entity (Nam)), 3510 Expr => 3511 Expression 3512 (Original_Node (Unit_Declaration_Node (Entity (Nam)))), 3513 N => N); 3514 end if; 3515 3516 -- Normal subprogram renaming (not renaming as body) 3517 3518 else 3519 Generate_Definition (New_S); 3520 New_Overloaded_Entity (New_S); 3521 3522 if not (Is_Entity_Name (Nam) 3523 and then Is_Intrinsic_Subprogram (Entity (Nam))) 3524 then 3525 Check_Delayed_Subprogram (New_S); 3526 end if; 3527 3528 -- Verify that a SPARK renaming does not declare a primitive 3529 -- operation of a tagged type. 3530 3531 Check_SPARK_Primitive_Operation (New_S); 3532 end if; 3533 3534 -- There is no need for elaboration checks on the new entity, which may 3535 -- be called before the next freezing point where the body will appear. 3536 -- Elaboration checks refer to the real entity, not the one created by 3537 -- the renaming declaration. 3538 3539 Set_Kill_Elaboration_Checks (New_S, True); 3540 3541 -- If we had a previous error, indicate a completion is present to stop 3542 -- junk cascaded messages, but don't take any further action. 3543 3544 if Etype (Nam) = Any_Type then 3545 Set_Has_Completion (New_S); 3546 return; 3547 3548 -- Case where name has the form of a selected component 3549 3550 elsif Nkind (Nam) = N_Selected_Component then 3551 3552 -- A name which has the form A.B can designate an entry of task A, a 3553 -- protected operation of protected object A, or finally a primitive 3554 -- operation of object A. In the later case, A is an object of some 3555 -- tagged type, or an access type that denotes one such. To further 3556 -- distinguish these cases, note that the scope of a task entry or 3557 -- protected operation is type of the prefix. 3558 3559 -- The prefix could be an overloaded function call that returns both 3560 -- kinds of operations. This overloading pathology is left to the 3561 -- dedicated reader ??? 3562 3563 declare 3564 T : constant Entity_Id := Etype (Prefix (Nam)); 3565 3566 begin 3567 if Present (T) 3568 and then 3569 (Is_Tagged_Type (T) 3570 or else 3571 (Is_Access_Type (T) 3572 and then Is_Tagged_Type (Designated_Type (T)))) 3573 and then Scope (Entity (Selector_Name (Nam))) /= T 3574 then 3575 Analyze_Renamed_Primitive_Operation 3576 (N, New_S, Present (Rename_Spec)); 3577 return; 3578 3579 else 3580 -- Renamed entity is an entry or protected operation. For those 3581 -- cases an explicit body is built (at the point of freezing of 3582 -- this entity) that contains a call to the renamed entity. 3583 3584 -- This is not allowed for renaming as body if the renamed 3585 -- spec is already frozen (see RM 8.5.4(5) for details). 3586 3587 if Present (Rename_Spec) and then Is_Frozen (Rename_Spec) then 3588 Error_Msg_N 3589 ("renaming-as-body cannot rename entry as subprogram", N); 3590 Error_Msg_NE 3591 ("\since & is already frozen (RM 8.5.4(5))", 3592 N, Rename_Spec); 3593 else 3594 Analyze_Renamed_Entry (N, New_S, Present (Rename_Spec)); 3595 end if; 3596 3597 return; 3598 end if; 3599 end; 3600 3601 -- Case where name is an explicit dereference X.all 3602 3603 elsif Nkind (Nam) = N_Explicit_Dereference then 3604 3605 -- Renamed entity is designated by access_to_subprogram expression. 3606 -- Must build body to encapsulate call, as in the entry case. 3607 3608 Analyze_Renamed_Dereference (N, New_S, Present (Rename_Spec)); 3609 return; 3610 3611 -- Indexed component 3612 3613 elsif Nkind (Nam) = N_Indexed_Component then 3614 Analyze_Renamed_Family_Member (N, New_S, Present (Rename_Spec)); 3615 return; 3616 3617 -- Character literal 3618 3619 elsif Nkind (Nam) = N_Character_Literal then 3620 Analyze_Renamed_Character (N, New_S, Present (Rename_Spec)); 3621 return; 3622 3623 -- Only remaining case is where we have a non-entity name, or a renaming 3624 -- of some other non-overloadable entity. 3625 3626 elsif not Is_Entity_Name (Nam) 3627 or else not Is_Overloadable (Entity (Nam)) 3628 then 3629 -- Do not mention the renaming if it comes from an instance 3630 3631 if not Is_Actual then 3632 Error_Msg_N ("expect valid subprogram name in renaming", N); 3633 else 3634 Error_Msg_NE ("no visible subprogram for formal&", N, Nam); 3635 end if; 3636 3637 return; 3638 end if; 3639 3640 -- Find the renamed entity that matches the given specification. Disable 3641 -- Ada_83 because there is no requirement of full conformance between 3642 -- renamed entity and new entity, even though the same circuit is used. 3643 3644 -- This is a bit of an odd case, which introduces a really irregular use 3645 -- of Ada_Version[_Explicit]. Would be nice to find cleaner way to do 3646 -- this. ??? 3647 3648 Ada_Version := Ada_Version_Type'Max (Ada_Version, Ada_95); 3649 Ada_Version_Pragma := Empty; 3650 Ada_Version_Explicit := Ada_Version; 3651 3652 if No (Old_S) then 3653 Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual); 3654 3655 -- The visible operation may be an inherited abstract operation that 3656 -- was overridden in the private part, in which case a call will 3657 -- dispatch to the overriding operation. Use the overriding one in 3658 -- the renaming declaration, to prevent spurious errors below. 3659 3660 if Is_Overloadable (Old_S) 3661 and then Is_Abstract_Subprogram (Old_S) 3662 and then No (DTC_Entity (Old_S)) 3663 and then Present (Alias (Old_S)) 3664 and then not Is_Abstract_Subprogram (Alias (Old_S)) 3665 and then Present (Overridden_Operation (Alias (Old_S))) 3666 then 3667 Old_S := Alias (Old_S); 3668 end if; 3669 3670 -- When the renamed subprogram is overloaded and used as an actual 3671 -- of a generic, its entity is set to the first available homonym. 3672 -- We must first disambiguate the name, then set the proper entity. 3673 3674 if Is_Actual and then Is_Overloaded (Nam) then 3675 Set_Entity (Nam, Old_S); 3676 end if; 3677 end if; 3678 3679 -- Most common case: subprogram renames subprogram. No body is generated 3680 -- in this case, so we must indicate the declaration is complete as is. 3681 -- and inherit various attributes of the renamed subprogram. 3682 3683 if No (Rename_Spec) then 3684 Set_Has_Completion (New_S); 3685 Set_Is_Imported (New_S, Is_Imported (Entity (Nam))); 3686 Set_Is_Pure (New_S, Is_Pure (Entity (Nam))); 3687 Set_Is_Preelaborated (New_S, Is_Preelaborated (Entity (Nam))); 3688 3689 -- Ada 2005 (AI-423): Check the consistency of null exclusions 3690 -- between a subprogram and its correct renaming. 3691 3692 -- Note: the Any_Id check is a guard that prevents compiler crashes 3693 -- when performing a null exclusion check between a renaming and a 3694 -- renamed subprogram that has been found to be illegal. 3695 3696 if Ada_Version >= Ada_2005 and then Entity (Nam) /= Any_Id then 3697 Check_Null_Exclusion 3698 (Ren => New_S, 3699 Sub => Entity (Nam)); 3700 end if; 3701 3702 -- Enforce the Ada 2005 rule that the renamed entity cannot require 3703 -- overriding. The flag Requires_Overriding is set very selectively 3704 -- and misses some other illegal cases. The additional conditions 3705 -- checked below are sufficient but not necessary ??? 3706 3707 -- The rule does not apply to the renaming generated for an actual 3708 -- subprogram in an instance. 3709 3710 if Is_Actual then 3711 null; 3712 3713 -- Guard against previous errors, and omit renamings of predefined 3714 -- operators. 3715 3716 elsif Ekind (Old_S) not in E_Function | E_Procedure then 3717 null; 3718 3719 elsif Requires_Overriding (Old_S) 3720 or else 3721 (Is_Abstract_Subprogram (Old_S) 3722 and then Present (Find_Dispatching_Type (Old_S)) 3723 and then not Is_Abstract_Type (Find_Dispatching_Type (Old_S))) 3724 then 3725 Error_Msg_N 3726 ("renamed entity cannot be subprogram that requires overriding " 3727 & "(RM 8.5.4 (5.1))", N); 3728 end if; 3729 3730 declare 3731 Prev : constant Entity_Id := Overridden_Operation (New_S); 3732 begin 3733 if Present (Prev) 3734 and then 3735 (Has_Non_Trivial_Precondition (Prev) 3736 or else Has_Non_Trivial_Precondition (Old_S)) 3737 then 3738 Error_Msg_NE 3739 ("conflicting inherited classwide preconditions in renaming " 3740 & "of& (RM 6.1.1 (17)", N, Old_S); 3741 end if; 3742 end; 3743 end if; 3744 3745 if Old_S /= Any_Id then 3746 if Is_Actual and then From_Default (N) then 3747 3748 -- This is an implicit reference to the default actual 3749 3750 Generate_Reference (Old_S, Nam, Typ => 'i', Force => True); 3751 3752 else 3753 Generate_Reference (Old_S, Nam); 3754 end if; 3755 3756 Check_Internal_Protected_Use (N, Old_S); 3757 3758 -- For a renaming-as-body, require subtype conformance, but if the 3759 -- declaration being completed has not been frozen, then inherit the 3760 -- convention of the renamed subprogram prior to checking conformance 3761 -- (unless the renaming has an explicit convention established; the 3762 -- rule stated in the RM doesn't seem to address this ???). 3763 3764 if Present (Rename_Spec) then 3765 Generate_Reference (Rename_Spec, Defining_Entity (Spec), 'b'); 3766 Style.Check_Identifier (Defining_Entity (Spec), Rename_Spec); 3767 3768 if not Is_Frozen (Rename_Spec) then 3769 if not Has_Convention_Pragma (Rename_Spec) then 3770 Set_Convention (New_S, Convention (Old_S)); 3771 end if; 3772 3773 if Ekind (Old_S) /= E_Operator then 3774 Check_Mode_Conformant (New_S, Old_S, Spec); 3775 end if; 3776 3777 if Original_Subprogram (Old_S) = Rename_Spec then 3778 Error_Msg_N ("unfrozen subprogram cannot rename itself", N); 3779 else 3780 Check_Formal_Subprogram_Conformance (New_S, Old_S, Spec); 3781 end if; 3782 else 3783 Check_Subtype_Conformant (New_S, Old_S, Spec); 3784 end if; 3785 3786 Check_Frozen_Renaming (N, Rename_Spec); 3787 3788 -- Check explicitly that renamed entity is not intrinsic, because 3789 -- in a generic the renamed body is not built. In this case, 3790 -- the renaming_as_body is a completion. 3791 3792 if Inside_A_Generic then 3793 if Is_Frozen (Rename_Spec) 3794 and then Is_Intrinsic_Subprogram (Old_S) 3795 then 3796 Error_Msg_N 3797 ("subprogram in renaming_as_body cannot be intrinsic", 3798 Name (N)); 3799 end if; 3800 3801 Set_Has_Completion (Rename_Spec); 3802 end if; 3803 3804 elsif Ekind (Old_S) /= E_Operator then 3805 3806 -- If this a defaulted subprogram for a class-wide actual there is 3807 -- no check for mode conformance, given that the signatures don't 3808 -- match (the source mentions T but the actual mentions T'Class). 3809 3810 if CW_Actual then 3811 null; 3812 3813 -- No need for a redundant error message if this is a nested 3814 -- instance, unless the current instantiation (of a child unit) 3815 -- is a compilation unit, which is not analyzed when the parent 3816 -- generic is analyzed. 3817 3818 elsif not Is_Actual 3819 or else No (Enclosing_Instance) 3820 or else Is_Compilation_Unit (Current_Scope) 3821 then 3822 Check_Mode_Conformant (New_S, Old_S); 3823 end if; 3824 end if; 3825 3826 if No (Rename_Spec) then 3827 3828 -- The parameter profile of the new entity is that of the renamed 3829 -- entity: the subtypes given in the specification are irrelevant. 3830 3831 Inherit_Renamed_Profile (New_S, Old_S); 3832 3833 -- A call to the subprogram is transformed into a call to the 3834 -- renamed entity. This is transitive if the renamed entity is 3835 -- itself a renaming. 3836 3837 if Present (Alias (Old_S)) then 3838 Set_Alias (New_S, Alias (Old_S)); 3839 else 3840 Set_Alias (New_S, Old_S); 3841 end if; 3842 3843 -- Note that we do not set Is_Intrinsic_Subprogram if we have a 3844 -- renaming as body, since the entity in this case is not an 3845 -- intrinsic (it calls an intrinsic, but we have a real body for 3846 -- this call, and it is in this body that the required intrinsic 3847 -- processing will take place). 3848 3849 -- Also, if this is a renaming of inequality, the renamed operator 3850 -- is intrinsic, but what matters is the corresponding equality 3851 -- operator, which may be user-defined. 3852 3853 Set_Is_Intrinsic_Subprogram 3854 (New_S, 3855 Is_Intrinsic_Subprogram (Old_S) 3856 and then 3857 (Chars (Old_S) /= Name_Op_Ne 3858 or else Ekind (Old_S) = E_Operator 3859 or else Is_Intrinsic_Subprogram 3860 (Corresponding_Equality (Old_S)))); 3861 3862 if Ekind (Alias (New_S)) = E_Operator then 3863 Set_Has_Delayed_Freeze (New_S, False); 3864 end if; 3865 3866 -- If the renaming corresponds to an association for an abstract 3867 -- formal subprogram, then various attributes must be set to 3868 -- indicate that the renaming is an abstract dispatching operation 3869 -- with a controlling type. 3870 3871 -- Skip this decoration when the renaming corresponds to an 3872 -- association with class-wide wrapper (see above) because such 3873 -- wrapper is neither abstract nor a dispatching operation (its 3874 -- body has the dispatching call to the wrapped primitive). 3875 3876 if Is_Actual 3877 and then Is_Abstract_Subprogram (Formal_Spec) 3878 and then No (Wrapped_Prim) 3879 then 3880 3881 -- Mark the renaming as abstract here, so Find_Dispatching_Type 3882 -- see it as corresponding to a generic association for a 3883 -- formal abstract subprogram 3884 3885 Set_Is_Abstract_Subprogram (New_S); 3886 3887 declare 3888 New_S_Ctrl_Type : constant Entity_Id := 3889 Find_Dispatching_Type (New_S); 3890 Old_S_Ctrl_Type : constant Entity_Id := 3891 Find_Dispatching_Type (Old_S); 3892 3893 begin 3894 3895 -- The actual must match the (instance of the) formal, 3896 -- and must be a controlling type. 3897 3898 if Old_S_Ctrl_Type /= New_S_Ctrl_Type 3899 or else No (New_S_Ctrl_Type) 3900 then 3901 if No (New_S_Ctrl_Type) then 3902 Error_Msg_N 3903 ("actual must be dispatching subprogram", Nam); 3904 else 3905 Error_Msg_NE 3906 ("actual must be dispatching subprogram for type&", 3907 Nam, New_S_Ctrl_Type); 3908 end if; 3909 3910 else 3911 Set_Is_Dispatching_Operation (New_S); 3912 Check_Controlling_Formals (New_S_Ctrl_Type, New_S); 3913 3914 -- If the actual in the formal subprogram is itself a 3915 -- formal abstract subprogram association, there's no 3916 -- dispatch table component or position to inherit. 3917 3918 if Present (DTC_Entity (Old_S)) then 3919 Set_DTC_Entity (New_S, DTC_Entity (Old_S)); 3920 Set_DT_Position_Value (New_S, DT_Position (Old_S)); 3921 end if; 3922 end if; 3923 end; 3924 end if; 3925 end if; 3926 3927 if Is_Actual then 3928 null; 3929 3930 -- The following is illegal, because F hides whatever other F may 3931 -- be around: 3932 -- function F (...) renames F; 3933 3934 elsif Old_S = New_S 3935 or else (Nkind (Nam) /= N_Expanded_Name 3936 and then Chars (Old_S) = Chars (New_S)) 3937 then 3938 Error_Msg_N ("subprogram cannot rename itself", N); 3939 3940 -- This is illegal even if we use a selector: 3941 -- function F (...) renames Pkg.F; 3942 -- because F is still hidden. 3943 3944 elsif Nkind (Nam) = N_Expanded_Name 3945 and then Entity (Prefix (Nam)) = Current_Scope 3946 and then Chars (Selector_Name (Nam)) = Chars (New_S) 3947 then 3948 -- This is an error, but we overlook the error and accept the 3949 -- renaming if the special Overriding_Renamings mode is in effect. 3950 3951 if not Overriding_Renamings then 3952 Error_Msg_NE 3953 ("implicit operation& is not visible (RM 8.3 (15))", 3954 Nam, Old_S); 3955 end if; 3956 end if; 3957 3958 Set_Convention (New_S, Convention (Old_S)); 3959 3960 if Is_Abstract_Subprogram (Old_S) then 3961 if Present (Rename_Spec) then 3962 Error_Msg_N 3963 ("a renaming-as-body cannot rename an abstract subprogram", 3964 N); 3965 Set_Has_Completion (Rename_Spec); 3966 else 3967 Set_Is_Abstract_Subprogram (New_S); 3968 end if; 3969 end if; 3970 3971 Check_Library_Unit_Renaming (N, Old_S); 3972 3973 -- Pathological case: procedure renames entry in the scope of its 3974 -- task. Entry is given by simple name, but body must be built for 3975 -- procedure. Of course if called it will deadlock. 3976 3977 if Ekind (Old_S) = E_Entry then 3978 Set_Has_Completion (New_S, False); 3979 Set_Alias (New_S, Empty); 3980 end if; 3981 3982 -- Do not freeze the renaming nor the renamed entity when the context 3983 -- is an enclosing generic. Freezing is an expansion activity, and in 3984 -- addition the renamed entity may depend on the generic formals of 3985 -- the enclosing generic. 3986 3987 if Is_Actual and not Inside_A_Generic then 3988 Freeze_Before (N, Old_S); 3989 Freeze_Actual_Profile; 3990 Set_Has_Delayed_Freeze (New_S, False); 3991 Freeze_Before (N, New_S); 3992 3993 if (Ekind (Old_S) = E_Procedure or else Ekind (Old_S) = E_Function) 3994 and then not Is_Abstract_Subprogram (Formal_Spec) 3995 then 3996 -- An abstract subprogram is only allowed as an actual in the 3997 -- case where the formal subprogram is also abstract. 3998 3999 if Is_Abstract_Subprogram (Old_S) then 4000 Error_Msg_N 4001 ("abstract subprogram not allowed as generic actual", Nam); 4002 end if; 4003 4004 -- AI12-0412: A primitive of an abstract type with Pre'Class 4005 -- or Post'Class aspects specified with nonstatic expressions 4006 -- is not allowed as actual for a nonabstract formal subprogram 4007 -- (see RM 6.1.1(18.2/5). 4008 4009 if Is_Dispatching_Operation (Old_S) 4010 and then 4011 Is_Prim_Of_Abst_Type_With_Nonstatic_CW_Pre_Post (Old_S) 4012 then 4013 Error_Msg_N 4014 ("primitive of abstract type with nonstatic class-wide " 4015 & "pre/postconditions not allowed as actual", 4016 Nam); 4017 end if; 4018 end if; 4019 end if; 4020 4021 else 4022 -- A common error is to assume that implicit operators for types are 4023 -- defined in Standard, or in the scope of a subtype. In those cases 4024 -- where the renamed entity is given with an expanded name, it is 4025 -- worth mentioning that operators for the type are not declared in 4026 -- the scope given by the prefix. 4027 4028 if Nkind (Nam) = N_Expanded_Name 4029 and then Nkind (Selector_Name (Nam)) = N_Operator_Symbol 4030 and then Scope (Entity (Nam)) = Standard_Standard 4031 then 4032 declare 4033 T : constant Entity_Id := 4034 Base_Type (Etype (First_Formal (New_S))); 4035 begin 4036 Error_Msg_Node_2 := Prefix (Nam); 4037 Error_Msg_NE 4038 ("operator for type& is not declared in&", Prefix (Nam), T); 4039 end; 4040 4041 else 4042 Error_Msg_NE 4043 ("no visible subprogram matches the specification for&", 4044 Spec, New_S); 4045 end if; 4046 4047 if Present (Candidate_Renaming) then 4048 declare 4049 F1 : Entity_Id; 4050 F2 : Entity_Id; 4051 T1 : Entity_Id; 4052 4053 begin 4054 F1 := First_Formal (Candidate_Renaming); 4055 F2 := First_Formal (New_S); 4056 T1 := First_Subtype (Etype (F1)); 4057 while Present (F1) and then Present (F2) loop 4058 Next_Formal (F1); 4059 Next_Formal (F2); 4060 end loop; 4061 4062 if Present (F1) and then Present (Default_Value (F1)) then 4063 if Present (Next_Formal (F1)) then 4064 Error_Msg_NE 4065 ("\missing specification for & and other formals with " 4066 & "defaults", Spec, F1); 4067 else 4068 Error_Msg_NE ("\missing specification for &", Spec, F1); 4069 end if; 4070 end if; 4071 4072 if Nkind (Nam) = N_Operator_Symbol 4073 and then From_Default (N) 4074 then 4075 Error_Msg_Node_2 := T1; 4076 Error_Msg_NE 4077 ("default & on & is not directly visible", Nam, Nam); 4078 end if; 4079 end; 4080 end if; 4081 end if; 4082 4083 -- Ada 2005 AI 404: if the new subprogram is dispatching, verify that 4084 -- controlling access parameters are known non-null for the renamed 4085 -- subprogram. Test also applies to a subprogram instantiation that 4086 -- is dispatching. Test is skipped if some previous error was detected 4087 -- that set Old_S to Any_Id. 4088 4089 if Ada_Version >= Ada_2005 4090 and then Old_S /= Any_Id 4091 and then not Is_Dispatching_Operation (Old_S) 4092 and then Is_Dispatching_Operation (New_S) 4093 then 4094 declare 4095 Old_F : Entity_Id; 4096 New_F : Entity_Id; 4097 4098 begin 4099 Old_F := First_Formal (Old_S); 4100 New_F := First_Formal (New_S); 4101 while Present (Old_F) loop 4102 if Ekind (Etype (Old_F)) = E_Anonymous_Access_Type 4103 and then Is_Controlling_Formal (New_F) 4104 and then not Can_Never_Be_Null (Old_F) 4105 then 4106 Error_Msg_N ("access parameter is controlling,", New_F); 4107 Error_Msg_NE 4108 ("\corresponding parameter of& must be explicitly null " 4109 & "excluding", New_F, Old_S); 4110 end if; 4111 4112 Next_Formal (Old_F); 4113 Next_Formal (New_F); 4114 end loop; 4115 end; 4116 end if; 4117 4118 -- A useful warning, suggested by Ada Bug Finder (Ada-Europe 2005) 4119 -- is to warn if an operator is being renamed as a different operator. 4120 -- If the operator is predefined, examine the kind of the entity, not 4121 -- the abbreviated declaration in Standard. 4122 4123 if Comes_From_Source (N) 4124 and then Present (Old_S) 4125 and then (Nkind (Old_S) = N_Defining_Operator_Symbol 4126 or else Ekind (Old_S) = E_Operator) 4127 and then Nkind (New_S) = N_Defining_Operator_Symbol 4128 and then Chars (Old_S) /= Chars (New_S) 4129 then 4130 Error_Msg_NE 4131 ("& is being renamed as a different operator??", N, Old_S); 4132 end if; 4133 4134 -- Check for renaming of obsolescent subprogram 4135 4136 Check_Obsolescent_2005_Entity (Entity (Nam), Nam); 4137 4138 -- Another warning or some utility: if the new subprogram as the same 4139 -- name as the old one, the old one is not hidden by an outer homograph, 4140 -- the new one is not a public symbol, and the old one is otherwise 4141 -- directly visible, the renaming is superfluous. 4142 4143 if Chars (Old_S) = Chars (New_S) 4144 and then Comes_From_Source (N) 4145 and then Scope (Old_S) /= Standard_Standard 4146 and then Warn_On_Redundant_Constructs 4147 and then (Is_Immediately_Visible (Old_S) 4148 or else Is_Potentially_Use_Visible (Old_S)) 4149 and then Is_Overloadable (Current_Scope) 4150 and then Chars (Current_Scope) /= Chars (Old_S) 4151 then 4152 Error_Msg_N 4153 ("redundant renaming, entity is directly visible?r?", Name (N)); 4154 end if; 4155 4156 -- Implementation-defined aspect specifications can appear in a renaming 4157 -- declaration, but not language-defined ones. The call to procedure 4158 -- Analyze_Aspect_Specifications will take care of this error check. 4159 4160 if Has_Aspects (N) then 4161 Analyze_Aspect_Specifications (N, New_S); 4162 end if; 4163 4164 -- AI12-0279 4165 4166 if Is_Actual 4167 and then Has_Yield_Aspect (Formal_Spec) 4168 and then not Has_Yield_Aspect (Old_S) 4169 then 4170 Error_Msg_Name_1 := Name_Yield; 4171 Error_Msg_N 4172 ("actual subprogram& must have aspect% to match formal", Name (N)); 4173 end if; 4174 4175 Ada_Version := Save_AV; 4176 Ada_Version_Pragma := Save_AVP; 4177 Ada_Version_Explicit := Save_AV_Exp; 4178 4179 -- Check if we are looking at an Ada 2012 defaulted formal subprogram 4180 -- and mark any use_package_clauses that affect the visibility of the 4181 -- implicit generic actual. 4182 4183 -- Also, we may be looking at an internal renaming of a user-defined 4184 -- subprogram created for a generic formal subprogram association, 4185 -- which will also have to be marked here. This can occur when the 4186 -- corresponding formal subprogram contains references to other generic 4187 -- formals. 4188 4189 if Is_Generic_Actual_Subprogram (New_S) 4190 and then (Is_Intrinsic_Subprogram (New_S) 4191 or else From_Default (N) 4192 or else Nkind (N) = N_Subprogram_Renaming_Declaration) 4193 then 4194 Mark_Use_Clauses (New_S); 4195 4196 -- Handle overloaded subprograms 4197 4198 if Present (Alias (New_S)) then 4199 Mark_Use_Clauses (Alias (New_S)); 4200 end if; 4201 end if; 4202 end Analyze_Subprogram_Renaming; 4203 4204 ------------------------- 4205 -- Analyze_Use_Package -- 4206 ------------------------- 4207 4208 -- Resolve the package names in the use clause, and make all the visible 4209 -- entities defined in the package potentially use-visible. If the package 4210 -- is already in use from a previous use clause, its visible entities are 4211 -- already use-visible. In that case, mark the occurrence as a redundant 4212 -- use. If the package is an open scope, i.e. if the use clause occurs 4213 -- within the package itself, ignore it. 4214 4215 procedure Analyze_Use_Package (N : Node_Id; Chain : Boolean := True) is 4216 procedure Analyze_Package_Name (Clause : Node_Id); 4217 -- Perform analysis on a package name from a use_package_clause 4218 4219 procedure Analyze_Package_Name_List (Head_Clause : Node_Id); 4220 -- Similar to Analyze_Package_Name but iterates over all the names 4221 -- in a use clause. 4222 4223 -------------------------- 4224 -- Analyze_Package_Name -- 4225 -------------------------- 4226 4227 procedure Analyze_Package_Name (Clause : Node_Id) is 4228 Pack : constant Node_Id := Name (Clause); 4229 Pref : Node_Id; 4230 4231 begin 4232 pragma Assert (Nkind (Clause) = N_Use_Package_Clause); 4233 Analyze (Pack); 4234 4235 -- Verify that the package standard is not directly named in a 4236 -- use_package_clause. 4237 4238 if Nkind (Parent (Clause)) = N_Compilation_Unit 4239 and then Nkind (Pack) = N_Expanded_Name 4240 then 4241 Pref := Prefix (Pack); 4242 4243 while Nkind (Pref) = N_Expanded_Name loop 4244 Pref := Prefix (Pref); 4245 end loop; 4246 4247 if Entity (Pref) = Standard_Standard then 4248 Error_Msg_N 4249 ("predefined package Standard cannot appear in a context " 4250 & "clause", Pref); 4251 end if; 4252 end if; 4253 end Analyze_Package_Name; 4254 4255 ------------------------------- 4256 -- Analyze_Package_Name_List -- 4257 ------------------------------- 4258 4259 procedure Analyze_Package_Name_List (Head_Clause : Node_Id) is 4260 Curr : Node_Id; 4261 4262 begin 4263 -- Due to the way source use clauses are split during parsing we are 4264 -- forced to simply iterate through all entities in scope until the 4265 -- clause representing the last name in the list is found. 4266 4267 Curr := Head_Clause; 4268 while Present (Curr) loop 4269 Analyze_Package_Name (Curr); 4270 4271 -- Stop iterating over the names in the use clause when we are at 4272 -- the last one. 4273 4274 exit when not More_Ids (Curr) and then Prev_Ids (Curr); 4275 Next (Curr); 4276 end loop; 4277 end Analyze_Package_Name_List; 4278 4279 -- Local variables 4280 4281 Pack : Entity_Id; 4282 4283 -- Start of processing for Analyze_Use_Package 4284 4285 begin 4286 Set_Hidden_By_Use_Clause (N, No_Elist); 4287 4288 -- Use clause not allowed in a spec of a predefined package declaration 4289 -- except that packages whose file name starts a-n are OK (these are 4290 -- children of Ada.Numerics, which are never loaded by Rtsfind). 4291 4292 if Is_Predefined_Unit (Current_Sem_Unit) 4293 and then Get_Name_String 4294 (Unit_File_Name (Current_Sem_Unit)) (1 .. 3) /= "a-n" 4295 and then Nkind (Unit (Cunit (Current_Sem_Unit))) = 4296 N_Package_Declaration 4297 then 4298 Error_Msg_N ("use clause not allowed in predefined spec", N); 4299 end if; 4300 4301 -- Loop through all package names from the original use clause in 4302 -- order to analyze referenced packages. A use_package_clause with only 4303 -- one name does not have More_Ids or Prev_Ids set, while a clause with 4304 -- More_Ids only starts the chain produced by the parser. 4305 4306 if not More_Ids (N) and then not Prev_Ids (N) then 4307 Analyze_Package_Name (N); 4308 4309 elsif More_Ids (N) and then not Prev_Ids (N) then 4310 Analyze_Package_Name_List (N); 4311 end if; 4312 4313 if not Is_Entity_Name (Name (N)) then 4314 Error_Msg_N ("& is not a package", Name (N)); 4315 4316 return; 4317 end if; 4318 4319 if Chain then 4320 Chain_Use_Clause (N); 4321 end if; 4322 4323 Pack := Entity (Name (N)); 4324 4325 -- There are many cases where scopes are manipulated during analysis, so 4326 -- check that Pack's current use clause has not already been chained 4327 -- before setting its previous use clause. 4328 4329 if Ekind (Pack) = E_Package 4330 and then Present (Current_Use_Clause (Pack)) 4331 and then Current_Use_Clause (Pack) /= N 4332 and then No (Prev_Use_Clause (N)) 4333 and then Prev_Use_Clause (Current_Use_Clause (Pack)) /= N 4334 then 4335 Set_Prev_Use_Clause (N, Current_Use_Clause (Pack)); 4336 end if; 4337 4338 -- Mark all entities as potentially use visible 4339 4340 if Ekind (Pack) /= E_Package and then Etype (Pack) /= Any_Type then 4341 if Ekind (Pack) = E_Generic_Package then 4342 Error_Msg_N -- CODEFIX 4343 ("a generic package is not allowed in a use clause", Name (N)); 4344 4345 elsif Is_Generic_Subprogram (Pack) then 4346 Error_Msg_N -- CODEFIX 4347 ("a generic subprogram is not allowed in a use clause", 4348 Name (N)); 4349 4350 elsif Is_Subprogram (Pack) then 4351 Error_Msg_N -- CODEFIX 4352 ("a subprogram is not allowed in a use clause", Name (N)); 4353 4354 else 4355 Error_Msg_N ("& is not allowed in a use clause", Name (N)); 4356 end if; 4357 4358 else 4359 if Nkind (Parent (N)) = N_Compilation_Unit then 4360 Check_In_Previous_With_Clause (N, Name (N)); 4361 end if; 4362 4363 Use_One_Package (N, Name (N)); 4364 end if; 4365 4366 Mark_Ghost_Clause (N); 4367 end Analyze_Use_Package; 4368 4369 ---------------------- 4370 -- Analyze_Use_Type -- 4371 ---------------------- 4372 4373 procedure Analyze_Use_Type (N : Node_Id; Chain : Boolean := True) is 4374 E : Entity_Id; 4375 Id : Node_Id; 4376 4377 begin 4378 Set_Hidden_By_Use_Clause (N, No_Elist); 4379 4380 -- Chain clause to list of use clauses in current scope when flagged 4381 4382 if Chain then 4383 Chain_Use_Clause (N); 4384 end if; 4385 4386 -- Obtain the base type of the type denoted within the use_type_clause's 4387 -- subtype mark. 4388 4389 Id := Subtype_Mark (N); 4390 Find_Type (Id); 4391 E := Base_Type (Entity (Id)); 4392 4393 -- There are many cases where a use_type_clause may be reanalyzed due to 4394 -- manipulation of the scope stack so we much guard against those cases 4395 -- here, otherwise, we must add the new use_type_clause to the previous 4396 -- use_type_clause chain in order to mark redundant use_type_clauses as 4397 -- used. When the redundant use-type clauses appear in a parent unit and 4398 -- a child unit we must prevent a circularity in the chain that would 4399 -- otherwise result from the separate steps of analysis and installation 4400 -- of the parent context. 4401 4402 if Present (Current_Use_Clause (E)) 4403 and then Current_Use_Clause (E) /= N 4404 and then Prev_Use_Clause (Current_Use_Clause (E)) /= N 4405 and then No (Prev_Use_Clause (N)) 4406 then 4407 Set_Prev_Use_Clause (N, Current_Use_Clause (E)); 4408 end if; 4409 4410 -- If the Used_Operations list is already initialized, the clause has 4411 -- been analyzed previously, and it is being reinstalled, for example 4412 -- when the clause appears in a package spec and we are compiling the 4413 -- corresponding package body. In that case, make the entities on the 4414 -- existing list use_visible, and mark the corresponding types In_Use. 4415 4416 if Present (Used_Operations (N)) then 4417 declare 4418 Elmt : Elmt_Id; 4419 4420 begin 4421 Use_One_Type (Subtype_Mark (N), Installed => True); 4422 4423 Elmt := First_Elmt (Used_Operations (N)); 4424 while Present (Elmt) loop 4425 Set_Is_Potentially_Use_Visible (Node (Elmt)); 4426 Next_Elmt (Elmt); 4427 end loop; 4428 end; 4429 4430 return; 4431 end if; 4432 4433 -- Otherwise, create new list and attach to it the operations that are 4434 -- made use-visible by the clause. 4435 4436 Set_Used_Operations (N, New_Elmt_List); 4437 E := Entity (Id); 4438 4439 if E /= Any_Type then 4440 Use_One_Type (Id); 4441 4442 if Nkind (Parent (N)) = N_Compilation_Unit then 4443 if Nkind (Id) = N_Identifier then 4444 Error_Msg_N ("type is not directly visible", Id); 4445 4446 elsif Is_Child_Unit (Scope (E)) 4447 and then Scope (E) /= System_Aux_Id 4448 then 4449 Check_In_Previous_With_Clause (N, Prefix (Id)); 4450 end if; 4451 end if; 4452 4453 else 4454 -- If the use_type_clause appears in a compilation unit context, 4455 -- check whether it comes from a unit that may appear in a 4456 -- limited_with_clause, for a better error message. 4457 4458 if Nkind (Parent (N)) = N_Compilation_Unit 4459 and then Nkind (Id) /= N_Identifier 4460 then 4461 declare 4462 Item : Node_Id; 4463 Pref : Node_Id; 4464 4465 function Mentioned (Nam : Node_Id) return Boolean; 4466 -- Check whether the prefix of expanded name for the type 4467 -- appears in the prefix of some limited_with_clause. 4468 4469 --------------- 4470 -- Mentioned -- 4471 --------------- 4472 4473 function Mentioned (Nam : Node_Id) return Boolean is 4474 begin 4475 return Nkind (Name (Item)) = N_Selected_Component 4476 and then Chars (Prefix (Name (Item))) = Chars (Nam); 4477 end Mentioned; 4478 4479 begin 4480 Pref := Prefix (Id); 4481 Item := First (Context_Items (Parent (N))); 4482 while Present (Item) and then Item /= N loop 4483 if Nkind (Item) = N_With_Clause 4484 and then Limited_Present (Item) 4485 and then Mentioned (Pref) 4486 then 4487 Change_Error_Text 4488 (Get_Msg_Id, "premature usage of incomplete type"); 4489 end if; 4490 4491 Next (Item); 4492 end loop; 4493 end; 4494 end if; 4495 end if; 4496 4497 Mark_Ghost_Clause (N); 4498 end Analyze_Use_Type; 4499 4500 ------------------------ 4501 -- Attribute_Renaming -- 4502 ------------------------ 4503 4504 procedure Attribute_Renaming (N : Node_Id) is 4505 Loc : constant Source_Ptr := Sloc (N); 4506 Nam : constant Node_Id := Name (N); 4507 Spec : constant Node_Id := Specification (N); 4508 New_S : constant Entity_Id := Defining_Unit_Name (Spec); 4509 Aname : constant Name_Id := Attribute_Name (Nam); 4510 4511 Form_Num : Nat := 0; 4512 Expr_List : List_Id := No_List; 4513 4514 Attr_Node : Node_Id; 4515 Body_Node : Node_Id; 4516 Param_Spec : Node_Id; 4517 4518 begin 4519 Generate_Definition (New_S); 4520 4521 -- This procedure is called in the context of subprogram renaming, and 4522 -- thus the attribute must be one that is a subprogram. All of those 4523 -- have at least one formal parameter, with the exceptions of the GNAT 4524 -- attribute 'Img, which GNAT treats as renameable. 4525 4526 if not Is_Non_Empty_List (Parameter_Specifications (Spec)) then 4527 if Aname /= Name_Img then 4528 Error_Msg_N 4529 ("subprogram renaming an attribute must have formals", N); 4530 return; 4531 end if; 4532 4533 else 4534 Param_Spec := First (Parameter_Specifications (Spec)); 4535 while Present (Param_Spec) loop 4536 Form_Num := Form_Num + 1; 4537 4538 if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then 4539 Find_Type (Parameter_Type (Param_Spec)); 4540 4541 -- The profile of the new entity denotes the base type (s) of 4542 -- the types given in the specification. For access parameters 4543 -- there are no subtypes involved. 4544 4545 Rewrite (Parameter_Type (Param_Spec), 4546 New_Occurrence_Of 4547 (Base_Type (Entity (Parameter_Type (Param_Spec))), Loc)); 4548 end if; 4549 4550 if No (Expr_List) then 4551 Expr_List := New_List; 4552 end if; 4553 4554 Append_To (Expr_List, 4555 Make_Identifier (Loc, 4556 Chars => Chars (Defining_Identifier (Param_Spec)))); 4557 4558 -- The expressions in the attribute reference are not freeze 4559 -- points. Neither is the attribute as a whole, see below. 4560 4561 Set_Must_Not_Freeze (Last (Expr_List)); 4562 Next (Param_Spec); 4563 end loop; 4564 end if; 4565 4566 -- Immediate error if too many formals. Other mismatches in number or 4567 -- types of parameters are detected when we analyze the body of the 4568 -- subprogram that we construct. 4569 4570 if Form_Num > 2 then 4571 Error_Msg_N ("too many formals for attribute", N); 4572 4573 -- Error if the attribute reference has expressions that look like 4574 -- formal parameters. 4575 4576 elsif Present (Expressions (Nam)) then 4577 Error_Msg_N ("illegal expressions in attribute reference", Nam); 4578 4579 elsif Aname in Name_Compose | Name_Exponent | Name_Leading_Part | 4580 Name_Pos | Name_Round | Name_Scaling | 4581 Name_Val 4582 then 4583 if Nkind (N) = N_Subprogram_Renaming_Declaration 4584 and then Present (Corresponding_Formal_Spec (N)) 4585 then 4586 Error_Msg_N 4587 ("generic actual cannot be attribute involving universal type", 4588 Nam); 4589 else 4590 Error_Msg_N 4591 ("attribute involving a universal type cannot be renamed", 4592 Nam); 4593 end if; 4594 end if; 4595 4596 -- Rewrite attribute node to have a list of expressions corresponding to 4597 -- the subprogram formals. A renaming declaration is not a freeze point, 4598 -- and the analysis of the attribute reference should not freeze the 4599 -- type of the prefix. We use the original node in the renaming so that 4600 -- its source location is preserved, and checks on stream attributes are 4601 -- properly applied. 4602 4603 Attr_Node := Relocate_Node (Nam); 4604 Set_Expressions (Attr_Node, Expr_List); 4605 4606 Set_Must_Not_Freeze (Attr_Node); 4607 Set_Must_Not_Freeze (Prefix (Nam)); 4608 4609 -- Case of renaming a function 4610 4611 if Nkind (Spec) = N_Function_Specification then 4612 if Is_Procedure_Attribute_Name (Aname) then 4613 Error_Msg_N ("attribute can only be renamed as procedure", Nam); 4614 return; 4615 end if; 4616 4617 Find_Type (Result_Definition (Spec)); 4618 Rewrite (Result_Definition (Spec), 4619 New_Occurrence_Of 4620 (Base_Type (Entity (Result_Definition (Spec))), Loc)); 4621 4622 Body_Node := 4623 Make_Subprogram_Body (Loc, 4624 Specification => Spec, 4625 Declarations => New_List, 4626 Handled_Statement_Sequence => 4627 Make_Handled_Sequence_Of_Statements (Loc, 4628 Statements => New_List ( 4629 Make_Simple_Return_Statement (Loc, 4630 Expression => Attr_Node)))); 4631 4632 -- Case of renaming a procedure 4633 4634 else 4635 if not Is_Procedure_Attribute_Name (Aname) then 4636 Error_Msg_N ("attribute can only be renamed as function", Nam); 4637 return; 4638 end if; 4639 4640 Body_Node := 4641 Make_Subprogram_Body (Loc, 4642 Specification => Spec, 4643 Declarations => New_List, 4644 Handled_Statement_Sequence => 4645 Make_Handled_Sequence_Of_Statements (Loc, 4646 Statements => New_List (Attr_Node))); 4647 end if; 4648 4649 -- Signal the ABE mechanism that the generated subprogram body has not 4650 -- ABE ramifications. 4651 4652 Set_Was_Attribute_Reference (Body_Node); 4653 4654 -- In case of tagged types we add the body of the generated function to 4655 -- the freezing actions of the type (because in the general case such 4656 -- type is still not frozen). We exclude from this processing generic 4657 -- formal subprograms found in instantiations. 4658 4659 -- We must exclude restricted run-time libraries because 4660 -- entity AST_Handler is defined in package System.Aux_Dec which is not 4661 -- available in those platforms. Note that we cannot use the function 4662 -- Restricted_Profile (instead of Configurable_Run_Time_Mode) because 4663 -- the ZFP run-time library is not defined as a profile, and we do not 4664 -- want to deal with AST_Handler in ZFP mode. 4665 4666 if not Configurable_Run_Time_Mode 4667 and then not Present (Corresponding_Formal_Spec (N)) 4668 and then not Is_RTE (Etype (Nam), RE_AST_Handler) 4669 then 4670 declare 4671 P : constant Node_Id := Prefix (Nam); 4672 4673 begin 4674 -- The prefix of 'Img is an object that is evaluated for each call 4675 -- of the function that renames it. 4676 4677 if Aname = Name_Img then 4678 Preanalyze_And_Resolve (P); 4679 4680 -- For all other attribute renamings, the prefix is a subtype 4681 4682 else 4683 Find_Type (P); 4684 end if; 4685 4686 -- If the target type is not yet frozen, add the body to the 4687 -- actions to be elaborated at freeze time. 4688 4689 if Is_Tagged_Type (Etype (P)) 4690 and then In_Open_Scopes (Scope (Etype (P))) 4691 then 4692 Append_Freeze_Action (Etype (P), Body_Node); 4693 else 4694 Rewrite (N, Body_Node); 4695 Analyze (N); 4696 Set_Etype (New_S, Base_Type (Etype (New_S))); 4697 end if; 4698 end; 4699 4700 -- Generic formal subprograms or AST_Handler renaming 4701 4702 else 4703 Rewrite (N, Body_Node); 4704 Analyze (N); 4705 Set_Etype (New_S, Base_Type (Etype (New_S))); 4706 end if; 4707 4708 if Is_Compilation_Unit (New_S) then 4709 Error_Msg_N 4710 ("a library unit can only rename another library unit", N); 4711 end if; 4712 4713 -- We suppress elaboration warnings for the resulting entity, since 4714 -- clearly they are not needed, and more particularly, in the case 4715 -- of a generic formal subprogram, the resulting entity can appear 4716 -- after the instantiation itself, and thus look like a bogus case 4717 -- of access before elaboration. 4718 4719 if Legacy_Elaboration_Checks then 4720 Set_Suppress_Elaboration_Warnings (New_S); 4721 end if; 4722 end Attribute_Renaming; 4723 4724 ---------------------- 4725 -- Chain_Use_Clause -- 4726 ---------------------- 4727 4728 procedure Chain_Use_Clause (N : Node_Id) is 4729 Level : Int := Scope_Stack.Last; 4730 Pack : Entity_Id; 4731 4732 begin 4733 -- Common case 4734 4735 if not Is_Compilation_Unit (Current_Scope) 4736 or else not Is_Child_Unit (Current_Scope) 4737 then 4738 null; 4739 4740 -- Common case for compilation unit 4741 4742 elsif Defining_Entity (Parent (N)) = Current_Scope then 4743 null; 4744 4745 else 4746 -- If declaration appears in some other scope, it must be in some 4747 -- parent unit when compiling a child. 4748 4749 Pack := Defining_Entity (Parent (N)); 4750 4751 if not In_Open_Scopes (Pack) then 4752 null; 4753 4754 -- If the use clause appears in an ancestor and we are in the 4755 -- private part of the immediate parent, the use clauses are 4756 -- already installed. 4757 4758 elsif Pack /= Scope (Current_Scope) 4759 and then In_Private_Part (Scope (Current_Scope)) 4760 then 4761 null; 4762 4763 else 4764 -- Find entry for parent unit in scope stack 4765 4766 while Scope_Stack.Table (Level).Entity /= Pack loop 4767 Level := Level - 1; 4768 end loop; 4769 end if; 4770 end if; 4771 4772 Set_Next_Use_Clause (N, 4773 Scope_Stack.Table (Level).First_Use_Clause); 4774 Scope_Stack.Table (Level).First_Use_Clause := N; 4775 end Chain_Use_Clause; 4776 4777 --------------------------- 4778 -- Check_Frozen_Renaming -- 4779 --------------------------- 4780 4781 procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id) is 4782 B_Node : Node_Id; 4783 Old_S : Entity_Id; 4784 4785 begin 4786 if Is_Frozen (Subp) and then not Has_Completion (Subp) then 4787 B_Node := 4788 Build_Renamed_Body 4789 (Parent (Declaration_Node (Subp)), Defining_Entity (N)); 4790 4791 if Is_Entity_Name (Name (N)) then 4792 Old_S := Entity (Name (N)); 4793 4794 if not Is_Frozen (Old_S) 4795 and then Operating_Mode /= Check_Semantics 4796 then 4797 Append_Freeze_Action (Old_S, B_Node); 4798 else 4799 Insert_After (N, B_Node); 4800 Analyze (B_Node); 4801 end if; 4802 4803 if Is_Intrinsic_Subprogram (Old_S) 4804 and then not In_Instance 4805 and then not Relaxed_RM_Semantics 4806 then 4807 Error_Msg_N 4808 ("subprogram used in renaming_as_body cannot be intrinsic", 4809 Name (N)); 4810 end if; 4811 4812 else 4813 Insert_After (N, B_Node); 4814 Analyze (B_Node); 4815 end if; 4816 end if; 4817 end Check_Frozen_Renaming; 4818 4819 ------------------------------- 4820 -- Set_Entity_Or_Discriminal -- 4821 ------------------------------- 4822 4823 procedure Set_Entity_Or_Discriminal (N : Node_Id; E : Entity_Id) is 4824 P : Node_Id; 4825 4826 begin 4827 -- If the entity is not a discriminant, or else expansion is disabled, 4828 -- simply set the entity. 4829 4830 if not In_Spec_Expression 4831 or else Ekind (E) /= E_Discriminant 4832 or else Inside_A_Generic 4833 then 4834 Set_Entity_With_Checks (N, E); 4835 4836 -- The replacement of a discriminant by the corresponding discriminal 4837 -- is not done for a task discriminant that appears in a default 4838 -- expression of an entry parameter. See Exp_Ch2.Expand_Discriminant 4839 -- for details on their handling. 4840 4841 elsif Is_Concurrent_Type (Scope (E)) then 4842 P := Parent (N); 4843 while Present (P) 4844 and then Nkind (P) not in 4845 N_Parameter_Specification | N_Component_Declaration 4846 loop 4847 P := Parent (P); 4848 end loop; 4849 4850 if Present (P) 4851 and then Nkind (P) = N_Parameter_Specification 4852 then 4853 null; 4854 4855 else 4856 Set_Entity (N, Discriminal (E)); 4857 end if; 4858 4859 -- Otherwise, this is a discriminant in a context in which 4860 -- it is a reference to the corresponding parameter of the 4861 -- init proc for the enclosing type. 4862 4863 else 4864 Set_Entity (N, Discriminal (E)); 4865 end if; 4866 end Set_Entity_Or_Discriminal; 4867 4868 ----------------------------------- 4869 -- Check_In_Previous_With_Clause -- 4870 ----------------------------------- 4871 4872 procedure Check_In_Previous_With_Clause (N, Nam : Node_Id) is 4873 Pack : constant Entity_Id := Entity (Original_Node (Nam)); 4874 Item : Node_Id; 4875 Par : Node_Id; 4876 4877 begin 4878 Item := First (Context_Items (Parent (N))); 4879 while Present (Item) and then Item /= N loop 4880 if Nkind (Item) = N_With_Clause 4881 4882 -- Protect the frontend against previous critical errors 4883 4884 and then Nkind (Name (Item)) /= N_Selected_Component 4885 and then Entity (Name (Item)) = Pack 4886 then 4887 Par := Nam; 4888 4889 -- Find root library unit in with_clause 4890 4891 while Nkind (Par) = N_Expanded_Name loop 4892 Par := Prefix (Par); 4893 end loop; 4894 4895 if Is_Child_Unit (Entity (Original_Node (Par))) then 4896 Error_Msg_NE ("& is not directly visible", Par, Entity (Par)); 4897 else 4898 return; 4899 end if; 4900 end if; 4901 4902 Next (Item); 4903 end loop; 4904 4905 -- On exit, package is not mentioned in a previous with_clause. 4906 -- Check if its prefix is. 4907 4908 if Nkind (Nam) = N_Expanded_Name then 4909 Check_In_Previous_With_Clause (N, Prefix (Nam)); 4910 4911 elsif Pack /= Any_Id then 4912 Error_Msg_NE ("& is not visible", Nam, Pack); 4913 end if; 4914 end Check_In_Previous_With_Clause; 4915 4916 --------------------------------- 4917 -- Check_Library_Unit_Renaming -- 4918 --------------------------------- 4919 4920 procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id) is 4921 New_E : Entity_Id; 4922 4923 begin 4924 if Nkind (Parent (N)) /= N_Compilation_Unit then 4925 return; 4926 4927 -- Check for library unit. Note that we used to check for the scope 4928 -- being Standard here, but that was wrong for Standard itself. 4929 4930 elsif not Is_Compilation_Unit (Old_E) 4931 and then not Is_Child_Unit (Old_E) 4932 then 4933 Error_Msg_N ("renamed unit must be a library unit", Name (N)); 4934 4935 -- Entities defined in Standard (operators and boolean literals) cannot 4936 -- be renamed as library units. 4937 4938 elsif Scope (Old_E) = Standard_Standard 4939 and then Sloc (Old_E) = Standard_Location 4940 then 4941 Error_Msg_N ("renamed unit must be a library unit", Name (N)); 4942 4943 elsif Present (Parent_Spec (N)) 4944 and then Nkind (Unit (Parent_Spec (N))) = N_Generic_Package_Declaration 4945 and then not Is_Child_Unit (Old_E) 4946 then 4947 Error_Msg_N 4948 ("renamed unit must be a child unit of generic parent", Name (N)); 4949 4950 elsif Nkind (N) in N_Generic_Renaming_Declaration 4951 and then Nkind (Name (N)) = N_Expanded_Name 4952 and then Is_Generic_Instance (Entity (Prefix (Name (N)))) 4953 and then Is_Generic_Unit (Old_E) 4954 then 4955 Error_Msg_N 4956 ("renamed generic unit must be a library unit", Name (N)); 4957 4958 elsif Is_Package_Or_Generic_Package (Old_E) then 4959 4960 -- Inherit categorization flags 4961 4962 New_E := Defining_Entity (N); 4963 Set_Is_Pure (New_E, Is_Pure (Old_E)); 4964 Set_Is_Preelaborated (New_E, Is_Preelaborated (Old_E)); 4965 Set_Is_Remote_Call_Interface (New_E, 4966 Is_Remote_Call_Interface (Old_E)); 4967 Set_Is_Remote_Types (New_E, Is_Remote_Types (Old_E)); 4968 Set_Is_Shared_Passive (New_E, Is_Shared_Passive (Old_E)); 4969 end if; 4970 end Check_Library_Unit_Renaming; 4971 4972 ------------------------ 4973 -- Enclosing_Instance -- 4974 ------------------------ 4975 4976 function Enclosing_Instance return Entity_Id is 4977 S : Entity_Id; 4978 4979 begin 4980 if not Is_Generic_Instance (Current_Scope) then 4981 return Empty; 4982 end if; 4983 4984 S := Scope (Current_Scope); 4985 while S /= Standard_Standard loop 4986 if Is_Generic_Instance (S) then 4987 return S; 4988 end if; 4989 4990 S := Scope (S); 4991 end loop; 4992 4993 return Empty; 4994 end Enclosing_Instance; 4995 4996 --------------- 4997 -- End_Scope -- 4998 --------------- 4999 5000 procedure End_Scope is 5001 Id : Entity_Id; 5002 Prev : Entity_Id; 5003 Outer : Entity_Id; 5004 5005 begin 5006 Id := First_Entity (Current_Scope); 5007 while Present (Id) loop 5008 -- An entity in the current scope is not necessarily the first one 5009 -- on its homonym chain. Find its predecessor if any, 5010 -- If it is an internal entity, it will not be in the visibility 5011 -- chain altogether, and there is nothing to unchain. 5012 5013 if Id /= Current_Entity (Id) then 5014 Prev := Current_Entity (Id); 5015 while Present (Prev) 5016 and then Present (Homonym (Prev)) 5017 and then Homonym (Prev) /= Id 5018 loop 5019 Prev := Homonym (Prev); 5020 end loop; 5021 5022 -- Skip to end of loop if Id is not in the visibility chain 5023 5024 if No (Prev) or else Homonym (Prev) /= Id then 5025 goto Next_Ent; 5026 end if; 5027 5028 else 5029 Prev := Empty; 5030 end if; 5031 5032 Set_Is_Immediately_Visible (Id, False); 5033 5034 Outer := Homonym (Id); 5035 while Present (Outer) and then Scope (Outer) = Current_Scope loop 5036 Outer := Homonym (Outer); 5037 end loop; 5038 5039 -- Reset homonym link of other entities, but do not modify link 5040 -- between entities in current scope, so that the back-end can have 5041 -- a proper count of local overloadings. 5042 5043 if No (Prev) then 5044 Set_Name_Entity_Id (Chars (Id), Outer); 5045 5046 elsif Scope (Prev) /= Scope (Id) then 5047 Set_Homonym (Prev, Outer); 5048 end if; 5049 5050 <<Next_Ent>> 5051 Next_Entity (Id); 5052 end loop; 5053 5054 -- If the scope generated freeze actions, place them before the 5055 -- current declaration and analyze them. Type declarations and 5056 -- the bodies of initialization procedures can generate such nodes. 5057 -- We follow the parent chain until we reach a list node, which is 5058 -- the enclosing list of declarations. If the list appears within 5059 -- a protected definition, move freeze nodes outside the protected 5060 -- type altogether. 5061 5062 if Present 5063 (Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions) 5064 then 5065 declare 5066 Decl : Node_Id; 5067 L : constant List_Id := Scope_Stack.Table 5068 (Scope_Stack.Last).Pending_Freeze_Actions; 5069 5070 begin 5071 if Is_Itype (Current_Scope) then 5072 Decl := Associated_Node_For_Itype (Current_Scope); 5073 else 5074 Decl := Parent (Current_Scope); 5075 end if; 5076 5077 Pop_Scope; 5078 5079 while not Is_List_Member (Decl) 5080 or else Nkind (Parent (Decl)) in N_Protected_Definition 5081 | N_Task_Definition 5082 loop 5083 Decl := Parent (Decl); 5084 end loop; 5085 5086 Insert_List_Before_And_Analyze (Decl, L); 5087 end; 5088 5089 else 5090 Pop_Scope; 5091 end if; 5092 end End_Scope; 5093 5094 --------------------- 5095 -- End_Use_Clauses -- 5096 --------------------- 5097 5098 procedure End_Use_Clauses (Clause : Node_Id) is 5099 U : Node_Id; 5100 5101 begin 5102 -- Remove use_type_clauses first, because they affect the visibility of 5103 -- operators in subsequent used packages. 5104 5105 U := Clause; 5106 while Present (U) loop 5107 if Nkind (U) = N_Use_Type_Clause then 5108 End_Use_Type (U); 5109 end if; 5110 5111 Next_Use_Clause (U); 5112 end loop; 5113 5114 U := Clause; 5115 while Present (U) loop 5116 if Nkind (U) = N_Use_Package_Clause then 5117 End_Use_Package (U); 5118 end if; 5119 5120 Next_Use_Clause (U); 5121 end loop; 5122 end End_Use_Clauses; 5123 5124 --------------------- 5125 -- End_Use_Package -- 5126 --------------------- 5127 5128 procedure End_Use_Package (N : Node_Id) is 5129 Pack : Entity_Id; 5130 Pack_Name : Node_Id; 5131 Id : Entity_Id; 5132 Elmt : Elmt_Id; 5133 5134 function Is_Primitive_Operator_In_Use 5135 (Op : Entity_Id; 5136 F : Entity_Id) return Boolean; 5137 -- Check whether Op is a primitive operator of a use-visible type 5138 5139 ---------------------------------- 5140 -- Is_Primitive_Operator_In_Use -- 5141 ---------------------------------- 5142 5143 function Is_Primitive_Operator_In_Use 5144 (Op : Entity_Id; 5145 F : Entity_Id) return Boolean 5146 is 5147 T : constant Entity_Id := Base_Type (Etype (F)); 5148 begin 5149 return In_Use (T) and then Scope (T) = Scope (Op); 5150 end Is_Primitive_Operator_In_Use; 5151 5152 -- Start of processing for End_Use_Package 5153 5154 begin 5155 Pack_Name := Name (N); 5156 5157 -- Test that Pack_Name actually denotes a package before processing 5158 5159 if Is_Entity_Name (Pack_Name) 5160 and then Ekind (Entity (Pack_Name)) = E_Package 5161 then 5162 Pack := Entity (Pack_Name); 5163 5164 if In_Open_Scopes (Pack) then 5165 null; 5166 5167 elsif not Redundant_Use (Pack_Name) then 5168 Set_In_Use (Pack, False); 5169 Set_Current_Use_Clause (Pack, Empty); 5170 5171 Id := First_Entity (Pack); 5172 while Present (Id) loop 5173 5174 -- Preserve use-visibility of operators that are primitive 5175 -- operators of a type that is use-visible through an active 5176 -- use_type_clause. 5177 5178 if Nkind (Id) = N_Defining_Operator_Symbol 5179 and then 5180 (Is_Primitive_Operator_In_Use (Id, First_Formal (Id)) 5181 or else 5182 (Present (Next_Formal (First_Formal (Id))) 5183 and then 5184 Is_Primitive_Operator_In_Use 5185 (Id, Next_Formal (First_Formal (Id))))) 5186 then 5187 null; 5188 else 5189 Set_Is_Potentially_Use_Visible (Id, False); 5190 end if; 5191 5192 if Is_Private_Type (Id) 5193 and then Present (Full_View (Id)) 5194 then 5195 Set_Is_Potentially_Use_Visible (Full_View (Id), False); 5196 end if; 5197 5198 Next_Entity (Id); 5199 end loop; 5200 5201 if Present (Renamed_Entity (Pack)) then 5202 Set_In_Use (Renamed_Entity (Pack), False); 5203 Set_Current_Use_Clause (Renamed_Entity (Pack), Empty); 5204 end if; 5205 5206 if Chars (Pack) = Name_System 5207 and then Scope (Pack) = Standard_Standard 5208 and then Present_System_Aux 5209 then 5210 Id := First_Entity (System_Aux_Id); 5211 while Present (Id) loop 5212 Set_Is_Potentially_Use_Visible (Id, False); 5213 5214 if Is_Private_Type (Id) 5215 and then Present (Full_View (Id)) 5216 then 5217 Set_Is_Potentially_Use_Visible (Full_View (Id), False); 5218 end if; 5219 5220 Next_Entity (Id); 5221 end loop; 5222 5223 Set_In_Use (System_Aux_Id, False); 5224 end if; 5225 else 5226 Set_Redundant_Use (Pack_Name, False); 5227 end if; 5228 end if; 5229 5230 if Present (Hidden_By_Use_Clause (N)) then 5231 Elmt := First_Elmt (Hidden_By_Use_Clause (N)); 5232 while Present (Elmt) loop 5233 declare 5234 E : constant Entity_Id := Node (Elmt); 5235 5236 begin 5237 -- Reset either Use_Visibility or Direct_Visibility, depending 5238 -- on how the entity was hidden by the use clause. 5239 5240 if In_Use (Scope (E)) 5241 and then Used_As_Generic_Actual (Scope (E)) 5242 then 5243 Set_Is_Potentially_Use_Visible (Node (Elmt)); 5244 else 5245 Set_Is_Immediately_Visible (Node (Elmt)); 5246 end if; 5247 5248 Next_Elmt (Elmt); 5249 end; 5250 end loop; 5251 5252 Set_Hidden_By_Use_Clause (N, No_Elist); 5253 end if; 5254 end End_Use_Package; 5255 5256 ------------------ 5257 -- End_Use_Type -- 5258 ------------------ 5259 5260 procedure End_Use_Type (N : Node_Id) is 5261 Elmt : Elmt_Id; 5262 Id : Entity_Id; 5263 T : Entity_Id; 5264 5265 -- Start of processing for End_Use_Type 5266 5267 begin 5268 Id := Subtype_Mark (N); 5269 5270 -- A call to Rtsfind may occur while analyzing a use_type_clause, in 5271 -- which case the type marks are not resolved yet, so guard against that 5272 -- here. 5273 5274 if Is_Entity_Name (Id) and then Present (Entity (Id)) then 5275 T := Entity (Id); 5276 5277 if T = Any_Type or else From_Limited_With (T) then 5278 null; 5279 5280 -- Note that the use_type_clause may mention a subtype of the type 5281 -- whose primitive operations have been made visible. Here as 5282 -- elsewhere, it is the base type that matters for visibility. 5283 5284 elsif In_Open_Scopes (Scope (Base_Type (T))) then 5285 null; 5286 5287 elsif not Redundant_Use (Id) then 5288 Set_In_Use (T, False); 5289 Set_In_Use (Base_Type (T), False); 5290 Set_Current_Use_Clause (T, Empty); 5291 Set_Current_Use_Clause (Base_Type (T), Empty); 5292 5293 -- See Use_One_Type for the rationale. This is a bit on the naive 5294 -- side, but should be good enough in practice. 5295 5296 if Is_Tagged_Type (T) then 5297 Set_In_Use (Class_Wide_Type (T), False); 5298 end if; 5299 end if; 5300 end if; 5301 5302 if Is_Empty_Elmt_List (Used_Operations (N)) then 5303 return; 5304 5305 else 5306 Elmt := First_Elmt (Used_Operations (N)); 5307 while Present (Elmt) loop 5308 Set_Is_Potentially_Use_Visible (Node (Elmt), False); 5309 Next_Elmt (Elmt); 5310 end loop; 5311 end if; 5312 end End_Use_Type; 5313 5314 -------------------- 5315 -- Entity_Of_Unit -- 5316 -------------------- 5317 5318 function Entity_Of_Unit (U : Node_Id) return Entity_Id is 5319 begin 5320 if Nkind (U) = N_Package_Instantiation and then Analyzed (U) then 5321 return Defining_Entity (Instance_Spec (U)); 5322 else 5323 return Defining_Entity (U); 5324 end if; 5325 end Entity_Of_Unit; 5326 5327 ---------------------- 5328 -- Find_Direct_Name -- 5329 ---------------------- 5330 5331 procedure Find_Direct_Name (N : Node_Id) is 5332 E : Entity_Id; 5333 E2 : Entity_Id; 5334 Msg : Boolean; 5335 5336 Homonyms : Entity_Id; 5337 -- Saves start of homonym chain 5338 5339 Inst : Entity_Id := Empty; 5340 -- Enclosing instance, if any 5341 5342 Nvis_Entity : Boolean; 5343 -- Set True to indicate that there is at least one entity on the homonym 5344 -- chain which, while not visible, is visible enough from the user point 5345 -- of view to warrant an error message of "not visible" rather than 5346 -- undefined. 5347 5348 Nvis_Is_Private_Subprg : Boolean := False; 5349 -- Ada 2005 (AI-262): Set True to indicate that a form of Beaujolais 5350 -- effect concerning library subprograms has been detected. Used to 5351 -- generate the precise error message. 5352 5353 function From_Actual_Package (E : Entity_Id) return Boolean; 5354 -- Returns true if the entity is an actual for a package that is itself 5355 -- an actual for a formal package of the current instance. Such an 5356 -- entity requires special handling because it may be use-visible but 5357 -- hides directly visible entities defined outside the instance, because 5358 -- the corresponding formal did so in the generic. 5359 5360 function Is_Actual_Parameter return Boolean; 5361 -- This function checks if the node N is an identifier that is an actual 5362 -- parameter of a procedure call. If so it returns True, otherwise it 5363 -- return False. The reason for this check is that at this stage we do 5364 -- not know what procedure is being called if the procedure might be 5365 -- overloaded, so it is premature to go setting referenced flags or 5366 -- making calls to Generate_Reference. We will wait till Resolve_Actuals 5367 -- for that processing. 5368 -- Note: there is a similar routine Sem_Util.Is_Actual_Parameter, but 5369 -- it works for both function and procedure calls, while here we are 5370 -- only concerned with procedure calls (and with entry calls as well, 5371 -- but they are parsed as procedure calls and only later rewritten to 5372 -- entry calls). 5373 5374 function Known_But_Invisible (E : Entity_Id) return Boolean; 5375 -- This function determines whether a reference to the entity E, which 5376 -- is not visible, can reasonably be considered to be known to the 5377 -- writer of the reference. This is a heuristic test, used only for 5378 -- the purposes of figuring out whether we prefer to complain that an 5379 -- entity is undefined or invisible (and identify the declaration of 5380 -- the invisible entity in the latter case). The point here is that we 5381 -- don't want to complain that something is invisible and then point to 5382 -- something entirely mysterious to the writer. 5383 5384 procedure Nvis_Messages; 5385 -- Called if there are no visible entries for N, but there is at least 5386 -- one non-directly visible, or hidden declaration. This procedure 5387 -- outputs an appropriate set of error messages. 5388 5389 procedure Undefined (Nvis : Boolean); 5390 -- This function is called if the current node has no corresponding 5391 -- visible entity or entities. The value set in Msg indicates whether 5392 -- an error message was generated (multiple error messages for the 5393 -- same variable are generally suppressed, see body for details). 5394 -- Msg is True if an error message was generated, False if not. This 5395 -- value is used by the caller to determine whether or not to output 5396 -- additional messages where appropriate. The parameter is set False 5397 -- to get the message "X is undefined", and True to get the message 5398 -- "X is not visible". 5399 5400 ------------------------- 5401 -- From_Actual_Package -- 5402 ------------------------- 5403 5404 function From_Actual_Package (E : Entity_Id) return Boolean is 5405 Scop : constant Entity_Id := Scope (E); 5406 -- Declared scope of candidate entity 5407 5408 function Declared_In_Actual (Pack : Entity_Id) return Boolean; 5409 -- Recursive function that does the work and examines actuals of 5410 -- actual packages of current instance. 5411 5412 ------------------------ 5413 -- Declared_In_Actual -- 5414 ------------------------ 5415 5416 function Declared_In_Actual (Pack : Entity_Id) return Boolean is 5417 pragma Assert (Ekind (Pack) = E_Package); 5418 Act : Entity_Id; 5419 begin 5420 if No (Associated_Formal_Package (Pack)) then 5421 return False; 5422 5423 else 5424 Act := First_Entity (Pack); 5425 while Present (Act) loop 5426 if Renamed_Entity (Pack) = Scop then 5427 return True; 5428 5429 -- Check for end of list of actuals 5430 5431 elsif Ekind (Act) = E_Package 5432 and then Renamed_Entity (Act) = Pack 5433 then 5434 return False; 5435 5436 elsif Ekind (Act) = E_Package 5437 and then Declared_In_Actual (Act) 5438 then 5439 return True; 5440 end if; 5441 5442 Next_Entity (Act); 5443 end loop; 5444 5445 return False; 5446 end if; 5447 end Declared_In_Actual; 5448 5449 -- Local variables 5450 5451 Act : Entity_Id; 5452 5453 -- Start of processing for From_Actual_Package 5454 5455 begin 5456 if not In_Instance then 5457 return False; 5458 5459 else 5460 Inst := Current_Scope; 5461 while Present (Inst) 5462 and then Ekind (Inst) /= E_Package 5463 and then not Is_Generic_Instance (Inst) 5464 loop 5465 Inst := Scope (Inst); 5466 end loop; 5467 5468 if No (Inst) then 5469 return False; 5470 end if; 5471 5472 Act := First_Entity (Inst); 5473 while Present (Act) loop 5474 if Ekind (Act) = E_Package 5475 and then Declared_In_Actual (Act) 5476 then 5477 return True; 5478 end if; 5479 5480 Next_Entity (Act); 5481 end loop; 5482 5483 return False; 5484 end if; 5485 end From_Actual_Package; 5486 5487 ------------------------- 5488 -- Is_Actual_Parameter -- 5489 ------------------------- 5490 5491 function Is_Actual_Parameter return Boolean is 5492 begin 5493 if Nkind (N) = N_Identifier then 5494 case Nkind (Parent (N)) is 5495 when N_Procedure_Call_Statement => 5496 return Is_List_Member (N) 5497 and then List_Containing (N) = 5498 Parameter_Associations (Parent (N)); 5499 5500 when N_Parameter_Association => 5501 return N = Explicit_Actual_Parameter (Parent (N)) 5502 and then Nkind (Parent (Parent (N))) = 5503 N_Procedure_Call_Statement; 5504 5505 when others => 5506 return False; 5507 end case; 5508 else 5509 return False; 5510 end if; 5511 end Is_Actual_Parameter; 5512 5513 ------------------------- 5514 -- Known_But_Invisible -- 5515 ------------------------- 5516 5517 function Known_But_Invisible (E : Entity_Id) return Boolean is 5518 Fname : File_Name_Type; 5519 5520 begin 5521 -- Entities in Standard are always considered to be known 5522 5523 if Sloc (E) <= Standard_Location then 5524 return True; 5525 5526 -- An entity that does not come from source is always considered 5527 -- to be unknown, since it is an artifact of code expansion. 5528 5529 elsif not Comes_From_Source (E) then 5530 return False; 5531 end if; 5532 5533 -- Here we have an entity that is not from package Standard, and 5534 -- which comes from Source. See if it comes from an internal file. 5535 5536 Fname := Unit_File_Name (Get_Source_Unit (E)); 5537 5538 -- Case of from internal file 5539 5540 if In_Internal_Unit (E) then 5541 5542 -- Private part entities in internal files are never considered 5543 -- to be known to the writer of normal application code. 5544 5545 if Is_Hidden (E) then 5546 return False; 5547 end if; 5548 5549 -- Entities from System packages other than System and 5550 -- System.Storage_Elements are not considered to be known. 5551 -- System.Auxxxx files are also considered known to the user. 5552 5553 -- Should refine this at some point to generally distinguish 5554 -- between known and unknown internal files ??? 5555 5556 Get_Name_String (Fname); 5557 5558 return 5559 Name_Len < 2 5560 or else 5561 Name_Buffer (1 .. 2) /= "s-" 5562 or else 5563 Name_Buffer (3 .. 8) = "stoele" 5564 or else 5565 Name_Buffer (3 .. 5) = "aux"; 5566 5567 -- If not an internal file, then entity is definitely known, even if 5568 -- it is in a private part (the message generated will note that it 5569 -- is in a private part). 5570 5571 else 5572 return True; 5573 end if; 5574 end Known_But_Invisible; 5575 5576 ------------------- 5577 -- Nvis_Messages -- 5578 ------------------- 5579 5580 procedure Nvis_Messages is 5581 Comp_Unit : Node_Id; 5582 Ent : Entity_Id; 5583 Found : Boolean := False; 5584 Hidden : Boolean := False; 5585 Item : Node_Id; 5586 5587 begin 5588 -- Ada 2005 (AI-262): Generate a precise error concerning the 5589 -- Beaujolais effect that was previously detected 5590 5591 if Nvis_Is_Private_Subprg then 5592 5593 pragma Assert (Nkind (E2) = N_Defining_Identifier 5594 and then Ekind (E2) = E_Function 5595 and then Scope (E2) = Standard_Standard 5596 and then Has_Private_With (E2)); 5597 5598 -- Find the sloc corresponding to the private with'ed unit 5599 5600 Comp_Unit := Cunit (Current_Sem_Unit); 5601 Error_Msg_Sloc := No_Location; 5602 5603 Item := First (Context_Items (Comp_Unit)); 5604 while Present (Item) loop 5605 if Nkind (Item) = N_With_Clause 5606 and then Private_Present (Item) 5607 and then Entity (Name (Item)) = E2 5608 then 5609 Error_Msg_Sloc := Sloc (Item); 5610 exit; 5611 end if; 5612 5613 Next (Item); 5614 end loop; 5615 5616 pragma Assert (Error_Msg_Sloc /= No_Location); 5617 5618 Error_Msg_N ("(Ada 2005): hidden by private with clause #", N); 5619 return; 5620 end if; 5621 5622 Undefined (Nvis => True); 5623 5624 if Msg then 5625 5626 -- First loop does hidden declarations 5627 5628 Ent := Homonyms; 5629 while Present (Ent) loop 5630 if Is_Potentially_Use_Visible (Ent) then 5631 if not Hidden then 5632 Error_Msg_N -- CODEFIX 5633 ("multiple use clauses cause hiding!", N); 5634 Hidden := True; 5635 end if; 5636 5637 Error_Msg_Sloc := Sloc (Ent); 5638 Error_Msg_N -- CODEFIX 5639 ("hidden declaration#!", N); 5640 end if; 5641 5642 Ent := Homonym (Ent); 5643 end loop; 5644 5645 -- If we found hidden declarations, then that's enough, don't 5646 -- bother looking for non-visible declarations as well. 5647 5648 if Hidden then 5649 return; 5650 end if; 5651 5652 -- Second loop does non-directly visible declarations 5653 5654 Ent := Homonyms; 5655 while Present (Ent) loop 5656 if not Is_Potentially_Use_Visible (Ent) then 5657 5658 -- Do not bother the user with unknown entities 5659 5660 if not Known_But_Invisible (Ent) then 5661 goto Continue; 5662 end if; 5663 5664 Error_Msg_Sloc := Sloc (Ent); 5665 5666 -- Output message noting that there is a non-visible 5667 -- declaration, distinguishing the private part case. 5668 5669 if Is_Hidden (Ent) then 5670 Error_Msg_N ("non-visible (private) declaration#!", N); 5671 5672 -- If the entity is declared in a generic package, it 5673 -- cannot be visible, so there is no point in adding it 5674 -- to the list of candidates if another homograph from a 5675 -- non-generic package has been seen. 5676 5677 elsif Ekind (Scope (Ent)) = E_Generic_Package 5678 and then Found 5679 then 5680 null; 5681 5682 else 5683 Error_Msg_N -- CODEFIX 5684 ("non-visible declaration#!", N); 5685 5686 if Ekind (Scope (Ent)) /= E_Generic_Package then 5687 Found := True; 5688 end if; 5689 5690 if Is_Compilation_Unit (Ent) 5691 and then 5692 Nkind (Parent (Parent (N))) = N_Use_Package_Clause 5693 then 5694 Error_Msg_Qual_Level := 99; 5695 Error_Msg_NE -- CODEFIX 5696 ("\\missing `WITH &;`", N, Ent); 5697 Error_Msg_Qual_Level := 0; 5698 end if; 5699 5700 if Ekind (Ent) = E_Discriminant 5701 and then Present (Corresponding_Discriminant (Ent)) 5702 and then Scope (Corresponding_Discriminant (Ent)) = 5703 Etype (Scope (Ent)) 5704 then 5705 Error_Msg_N 5706 ("inherited discriminant not allowed here" & 5707 " (RM 3.8 (12), 3.8.1 (6))!", N); 5708 end if; 5709 end if; 5710 5711 -- Set entity and its containing package as referenced. We 5712 -- can't be sure of this, but this seems a better choice 5713 -- to avoid unused entity messages. 5714 5715 if Comes_From_Source (Ent) then 5716 Set_Referenced (Ent); 5717 Set_Referenced (Cunit_Entity (Get_Source_Unit (Ent))); 5718 end if; 5719 end if; 5720 5721 <<Continue>> 5722 Ent := Homonym (Ent); 5723 end loop; 5724 end if; 5725 end Nvis_Messages; 5726 5727 --------------- 5728 -- Undefined -- 5729 --------------- 5730 5731 procedure Undefined (Nvis : Boolean) is 5732 Emsg : Error_Msg_Id; 5733 5734 begin 5735 -- We should never find an undefined internal name. If we do, then 5736 -- see if we have previous errors. If so, ignore on the grounds that 5737 -- it is probably a cascaded message (e.g. a block label from a badly 5738 -- formed block). If no previous errors, then we have a real internal 5739 -- error of some kind so raise an exception. 5740 5741 if Is_Internal_Name (Chars (N)) then 5742 if Total_Errors_Detected /= 0 then 5743 return; 5744 else 5745 raise Program_Error; 5746 end if; 5747 end if; 5748 5749 -- A very specialized error check, if the undefined variable is 5750 -- a case tag, and the case type is an enumeration type, check 5751 -- for a possible misspelling, and if so, modify the identifier 5752 5753 -- Named aggregate should also be handled similarly ??? 5754 5755 if Nkind (N) = N_Identifier 5756 and then Nkind (Parent (N)) = N_Case_Statement_Alternative 5757 then 5758 declare 5759 Case_Stm : constant Node_Id := Parent (Parent (N)); 5760 Case_Typ : constant Entity_Id := Etype (Expression (Case_Stm)); 5761 5762 Lit : Node_Id; 5763 5764 begin 5765 if Is_Enumeration_Type (Case_Typ) 5766 and then not Is_Standard_Character_Type (Case_Typ) 5767 then 5768 Lit := First_Literal (Case_Typ); 5769 Get_Name_String (Chars (Lit)); 5770 5771 if Chars (Lit) /= Chars (N) 5772 and then Is_Bad_Spelling_Of (Chars (N), Chars (Lit)) 5773 then 5774 Error_Msg_Node_2 := Lit; 5775 Error_Msg_N -- CODEFIX 5776 ("& is undefined, assume misspelling of &", N); 5777 Rewrite (N, New_Occurrence_Of (Lit, Sloc (N))); 5778 return; 5779 end if; 5780 5781 Next_Literal (Lit); 5782 end if; 5783 end; 5784 end if; 5785 5786 -- Normal processing 5787 5788 Set_Entity (N, Any_Id); 5789 Set_Etype (N, Any_Type); 5790 5791 -- We use the table Urefs to keep track of entities for which we 5792 -- have issued errors for undefined references. Multiple errors 5793 -- for a single name are normally suppressed, however we modify 5794 -- the error message to alert the programmer to this effect. 5795 5796 for J in Urefs.First .. Urefs.Last loop 5797 if Chars (N) = Chars (Urefs.Table (J).Node) then 5798 if Urefs.Table (J).Err /= No_Error_Msg 5799 and then Sloc (N) /= Urefs.Table (J).Loc 5800 then 5801 Error_Msg_Node_1 := Urefs.Table (J).Node; 5802 5803 if Urefs.Table (J).Nvis then 5804 Change_Error_Text (Urefs.Table (J).Err, 5805 "& is not visible (more references follow)"); 5806 else 5807 Change_Error_Text (Urefs.Table (J).Err, 5808 "& is undefined (more references follow)"); 5809 end if; 5810 5811 Urefs.Table (J).Err := No_Error_Msg; 5812 end if; 5813 5814 -- Although we will set Msg False, and thus suppress the 5815 -- message, we also set Error_Posted True, to avoid any 5816 -- cascaded messages resulting from the undefined reference. 5817 5818 Msg := False; 5819 Set_Error_Posted (N); 5820 return; 5821 end if; 5822 end loop; 5823 5824 -- If entry not found, this is first undefined occurrence 5825 5826 if Nvis then 5827 Error_Msg_N ("& is not visible!", N); 5828 Emsg := Get_Msg_Id; 5829 5830 else 5831 Error_Msg_N ("& is undefined!", N); 5832 Emsg := Get_Msg_Id; 5833 5834 -- A very bizarre special check, if the undefined identifier 5835 -- is Put or Put_Line, then add a special error message (since 5836 -- this is a very common error for beginners to make). 5837 5838 if Chars (N) in Name_Put | Name_Put_Line then 5839 Error_Msg_N -- CODEFIX 5840 ("\\possible missing `WITH Ada.Text_'I'O; " & 5841 "USE Ada.Text_'I'O`!", N); 5842 5843 -- Another special check if N is the prefix of a selected 5844 -- component which is a known unit: add message complaining 5845 -- about missing with for this unit. 5846 5847 elsif Nkind (Parent (N)) = N_Selected_Component 5848 and then N = Prefix (Parent (N)) 5849 and then Is_Known_Unit (Parent (N)) 5850 then 5851 declare 5852 P : Node_Id := Parent (N); 5853 begin 5854 Error_Msg_Name_1 := Chars (N); 5855 Error_Msg_Name_2 := Chars (Selector_Name (P)); 5856 5857 if Nkind (Parent (P)) = N_Selected_Component 5858 and then Is_Known_Unit (Parent (P)) 5859 then 5860 P := Parent (P); 5861 Error_Msg_Name_3 := Chars (Selector_Name (P)); 5862 Error_Msg_N -- CODEFIX 5863 ("\\missing `WITH %.%.%;`", N); 5864 5865 else 5866 Error_Msg_N -- CODEFIX 5867 ("\\missing `WITH %.%;`", N); 5868 end if; 5869 end; 5870 end if; 5871 5872 -- Now check for possible misspellings 5873 5874 declare 5875 E : Entity_Id; 5876 Ematch : Entity_Id := Empty; 5877 begin 5878 for Nam in First_Name_Id .. Last_Name_Id loop 5879 E := Get_Name_Entity_Id (Nam); 5880 5881 if Present (E) 5882 and then (Is_Immediately_Visible (E) 5883 or else 5884 Is_Potentially_Use_Visible (E)) 5885 then 5886 if Is_Bad_Spelling_Of (Chars (N), Nam) then 5887 Ematch := E; 5888 exit; 5889 end if; 5890 end if; 5891 end loop; 5892 5893 if Present (Ematch) then 5894 Error_Msg_NE -- CODEFIX 5895 ("\possible misspelling of&", N, Ematch); 5896 end if; 5897 end; 5898 end if; 5899 5900 -- Make entry in undefined references table unless the full errors 5901 -- switch is set, in which case by refraining from generating the 5902 -- table entry we guarantee that we get an error message for every 5903 -- undefined reference. The entry is not added if we are ignoring 5904 -- errors. 5905 5906 if not All_Errors_Mode 5907 and then Ignore_Errors_Enable = 0 5908 and then not Get_Ignore_Errors 5909 then 5910 Urefs.Append ( 5911 (Node => N, 5912 Err => Emsg, 5913 Nvis => Nvis, 5914 Loc => Sloc (N))); 5915 end if; 5916 5917 Msg := True; 5918 end Undefined; 5919 5920 -- Local variables 5921 5922 Nested_Inst : Entity_Id := Empty; 5923 -- The entity of a nested instance which appears within Inst (if any) 5924 5925 -- Start of processing for Find_Direct_Name 5926 5927 begin 5928 -- If the entity pointer is already set, this is an internal node, or 5929 -- a node that is analyzed more than once, after a tree modification. 5930 -- In such a case there is no resolution to perform, just set the type. 5931 5932 if Present (Entity (N)) then 5933 if Is_Type (Entity (N)) then 5934 Set_Etype (N, Entity (N)); 5935 5936 -- The exception to this general rule are constants associated with 5937 -- discriminals of protected types because for each protected op 5938 -- a new set of discriminals is internally created by the frontend 5939 -- (see Exp_Ch9.Set_Discriminals), and the current decoration of the 5940 -- entity pointer may have been set as part of a preanalysis, where 5941 -- discriminals still reference the first subprogram or entry to be 5942 -- expanded (see Expand_Protected_Body_Declarations). 5943 5944 elsif Full_Analysis 5945 and then Ekind (Entity (N)) = E_Constant 5946 and then Present (Discriminal_Link (Entity (N))) 5947 and then Is_Protected_Type (Scope (Discriminal_Link (Entity (N)))) 5948 then 5949 goto Find_Name; 5950 5951 else 5952 declare 5953 Entyp : constant Entity_Id := Etype (Entity (N)); 5954 5955 begin 5956 -- One special case here. If the Etype field is already set, 5957 -- and references the packed array type corresponding to the 5958 -- etype of the referenced entity, then leave it alone. This 5959 -- happens for trees generated from Exp_Pakd, where expressions 5960 -- can be deliberately "mis-typed" to the packed array type. 5961 5962 if Is_Packed_Array (Entyp) 5963 and then Present (Etype (N)) 5964 and then Etype (N) = Packed_Array_Impl_Type (Entyp) 5965 then 5966 null; 5967 5968 -- If not that special case, then just reset the Etype 5969 5970 else 5971 Set_Etype (N, Etype (Entity (N))); 5972 end if; 5973 end; 5974 end if; 5975 5976 -- Although the marking of use clauses happens at the end of 5977 -- Find_Direct_Name, a certain case where a generic actual satisfies 5978 -- a use clause must be checked here due to how the generic machinery 5979 -- handles the analysis of said actuals. 5980 5981 if In_Instance 5982 and then Nkind (Parent (N)) = N_Generic_Association 5983 then 5984 Mark_Use_Clauses (Entity (N)); 5985 end if; 5986 5987 return; 5988 end if; 5989 5990 <<Find_Name>> 5991 5992 -- Preserve relevant elaboration-related attributes of the context which 5993 -- are no longer available or very expensive to recompute once analysis, 5994 -- resolution, and expansion are over. 5995 5996 if Nkind (N) = N_Identifier then 5997 Mark_Elaboration_Attributes 5998 (N_Id => N, 5999 Checks => True, 6000 Modes => True, 6001 Warnings => True); 6002 end if; 6003 6004 -- Here if Entity pointer was not set, we need full visibility analysis 6005 -- First we generate debugging output if the debug E flag is set. 6006 6007 if Debug_Flag_E then 6008 Write_Str ("Looking for "); 6009 Write_Name (Chars (N)); 6010 Write_Eol; 6011 end if; 6012 6013 Homonyms := Current_Entity (N); 6014 Nvis_Entity := False; 6015 6016 E := Homonyms; 6017 while Present (E) loop 6018 6019 -- If entity is immediately visible or potentially use visible, then 6020 -- process the entity and we are done. 6021 6022 if Is_Immediately_Visible (E) then 6023 goto Immediately_Visible_Entity; 6024 6025 elsif Is_Potentially_Use_Visible (E) then 6026 goto Potentially_Use_Visible_Entity; 6027 6028 -- Note if a known but invisible entity encountered 6029 6030 elsif Known_But_Invisible (E) then 6031 Nvis_Entity := True; 6032 end if; 6033 6034 -- Move to next entity in chain and continue search 6035 6036 E := Homonym (E); 6037 end loop; 6038 6039 -- If no entries on homonym chain that were potentially visible, 6040 -- and no entities reasonably considered as non-visible, then 6041 -- we have a plain undefined reference, with no additional 6042 -- explanation required. 6043 6044 if not Nvis_Entity then 6045 Undefined (Nvis => False); 6046 6047 -- Otherwise there is at least one entry on the homonym chain that 6048 -- is reasonably considered as being known and non-visible. 6049 6050 else 6051 Nvis_Messages; 6052 end if; 6053 6054 goto Done; 6055 6056 -- Processing for a potentially use visible entry found. We must search 6057 -- the rest of the homonym chain for two reasons. First, if there is a 6058 -- directly visible entry, then none of the potentially use-visible 6059 -- entities are directly visible (RM 8.4(10)). Second, we need to check 6060 -- for the case of multiple potentially use-visible entries hiding one 6061 -- another and as a result being non-directly visible (RM 8.4(11)). 6062 6063 <<Potentially_Use_Visible_Entity>> declare 6064 Only_One_Visible : Boolean := True; 6065 All_Overloadable : Boolean := Is_Overloadable (E); 6066 6067 begin 6068 E2 := Homonym (E); 6069 while Present (E2) loop 6070 if Is_Immediately_Visible (E2) then 6071 6072 -- If the use-visible entity comes from the actual for a 6073 -- formal package, it hides a directly visible entity from 6074 -- outside the instance. 6075 6076 if From_Actual_Package (E) 6077 and then Scope_Depth (Scope (E2)) < Scope_Depth (Inst) 6078 then 6079 goto Found; 6080 else 6081 E := E2; 6082 goto Immediately_Visible_Entity; 6083 end if; 6084 6085 elsif Is_Potentially_Use_Visible (E2) then 6086 Only_One_Visible := False; 6087 All_Overloadable := All_Overloadable and Is_Overloadable (E2); 6088 6089 -- Ada 2005 (AI-262): Protect against a form of Beaujolais effect 6090 -- that can occur in private_with clauses. Example: 6091 6092 -- with A; 6093 -- private with B; package A is 6094 -- package C is function B return Integer; 6095 -- use A; end A; 6096 -- V1 : Integer := B; 6097 -- private function B return Integer; 6098 -- V2 : Integer := B; 6099 -- end C; 6100 6101 -- V1 resolves to A.B, but V2 resolves to library unit B 6102 6103 elsif Ekind (E2) = E_Function 6104 and then Scope (E2) = Standard_Standard 6105 and then Has_Private_With (E2) 6106 then 6107 Only_One_Visible := False; 6108 All_Overloadable := False; 6109 Nvis_Is_Private_Subprg := True; 6110 exit; 6111 end if; 6112 6113 E2 := Homonym (E2); 6114 end loop; 6115 6116 -- On falling through this loop, we have checked that there are no 6117 -- immediately visible entities. Only_One_Visible is set if exactly 6118 -- one potentially use visible entity exists. All_Overloadable is 6119 -- set if all the potentially use visible entities are overloadable. 6120 -- The condition for legality is that either there is one potentially 6121 -- use visible entity, or if there is more than one, then all of them 6122 -- are overloadable. 6123 6124 if Only_One_Visible or All_Overloadable then 6125 goto Found; 6126 6127 -- If there is more than one potentially use-visible entity and at 6128 -- least one of them non-overloadable, we have an error (RM 8.4(11)). 6129 -- Note that E points to the first such entity on the homonym list. 6130 6131 else 6132 -- If one of the entities is declared in an actual package, it 6133 -- was visible in the generic, and takes precedence over other 6134 -- entities that are potentially use-visible. The same applies 6135 -- if the entity is declared in a local instantiation of the 6136 -- current instance. 6137 6138 if In_Instance then 6139 6140 -- Find the current instance 6141 6142 Inst := Current_Scope; 6143 while Present (Inst) and then Inst /= Standard_Standard loop 6144 if Is_Generic_Instance (Inst) then 6145 exit; 6146 end if; 6147 6148 Inst := Scope (Inst); 6149 end loop; 6150 6151 -- Reexamine the candidate entities, giving priority to those 6152 -- that were visible within the generic. 6153 6154 E2 := E; 6155 while Present (E2) loop 6156 Nested_Inst := Nearest_Enclosing_Instance (E2); 6157 6158 -- The entity is declared within an actual package, or in a 6159 -- nested instance. The ">=" accounts for the case where the 6160 -- current instance and the nested instance are the same. 6161 6162 if From_Actual_Package (E2) 6163 or else (Present (Nested_Inst) 6164 and then Scope_Depth (Nested_Inst) >= 6165 Scope_Depth (Inst)) 6166 then 6167 E := E2; 6168 goto Found; 6169 end if; 6170 6171 E2 := Homonym (E2); 6172 end loop; 6173 6174 Nvis_Messages; 6175 goto Done; 6176 6177 elsif Is_Predefined_Unit (Current_Sem_Unit) then 6178 -- A use clause in the body of a system file creates conflict 6179 -- with some entity in a user scope, while rtsfind is active. 6180 -- Keep only the entity coming from another predefined unit. 6181 6182 E2 := E; 6183 while Present (E2) loop 6184 if In_Predefined_Unit (E2) then 6185 E := E2; 6186 goto Found; 6187 end if; 6188 6189 E2 := Homonym (E2); 6190 end loop; 6191 6192 -- Entity must exist because predefined unit is correct 6193 6194 raise Program_Error; 6195 6196 else 6197 Nvis_Messages; 6198 goto Done; 6199 end if; 6200 end if; 6201 end; 6202 6203 -- Come here with E set to the first immediately visible entity on 6204 -- the homonym chain. This is the one we want unless there is another 6205 -- immediately visible entity further on in the chain for an inner 6206 -- scope (RM 8.3(8)). 6207 6208 <<Immediately_Visible_Entity>> declare 6209 Level : Int; 6210 Scop : Entity_Id; 6211 6212 begin 6213 -- Find scope level of initial entity. When compiling through 6214 -- Rtsfind, the previous context is not completely invisible, and 6215 -- an outer entity may appear on the chain, whose scope is below 6216 -- the entry for Standard that delimits the current scope stack. 6217 -- Indicate that the level for this spurious entry is outside of 6218 -- the current scope stack. 6219 6220 Level := Scope_Stack.Last; 6221 loop 6222 Scop := Scope_Stack.Table (Level).Entity; 6223 exit when Scop = Scope (E); 6224 Level := Level - 1; 6225 exit when Scop = Standard_Standard; 6226 end loop; 6227 6228 -- Now search remainder of homonym chain for more inner entry 6229 -- If the entity is Standard itself, it has no scope, and we 6230 -- compare it with the stack entry directly. 6231 6232 E2 := Homonym (E); 6233 while Present (E2) loop 6234 if Is_Immediately_Visible (E2) then 6235 6236 -- If a generic package contains a local declaration that 6237 -- has the same name as the generic, there may be a visibility 6238 -- conflict in an instance, where the local declaration must 6239 -- also hide the name of the corresponding package renaming. 6240 -- We check explicitly for a package declared by a renaming, 6241 -- whose renamed entity is an instance that is on the scope 6242 -- stack, and that contains a homonym in the same scope. Once 6243 -- we have found it, we know that the package renaming is not 6244 -- immediately visible, and that the identifier denotes the 6245 -- other entity (and its homonyms if overloaded). 6246 6247 if Scope (E) = Scope (E2) 6248 and then Ekind (E) = E_Package 6249 and then Present (Renamed_Entity (E)) 6250 and then Is_Generic_Instance (Renamed_Entity (E)) 6251 and then In_Open_Scopes (Renamed_Entity (E)) 6252 and then Comes_From_Source (N) 6253 then 6254 Set_Is_Immediately_Visible (E, False); 6255 E := E2; 6256 6257 else 6258 for J in Level + 1 .. Scope_Stack.Last loop 6259 if Scope_Stack.Table (J).Entity = Scope (E2) 6260 or else Scope_Stack.Table (J).Entity = E2 6261 then 6262 Level := J; 6263 E := E2; 6264 exit; 6265 end if; 6266 end loop; 6267 end if; 6268 end if; 6269 6270 E2 := Homonym (E2); 6271 end loop; 6272 6273 -- At the end of that loop, E is the innermost immediately 6274 -- visible entity, so we are all set. 6275 end; 6276 6277 -- Come here with entity found, and stored in E 6278 6279 <<Found>> begin 6280 6281 -- Check violation of No_Wide_Characters restriction 6282 6283 Check_Wide_Character_Restriction (E, N); 6284 6285 -- When distribution features are available (Get_PCS_Name /= 6286 -- Name_No_DSA), a remote access-to-subprogram type is converted 6287 -- into a record type holding whatever information is needed to 6288 -- perform a remote call on an RCI subprogram. In that case we 6289 -- rewrite any occurrence of the RAS type into the equivalent record 6290 -- type here. 'Access attribute references and RAS dereferences are 6291 -- then implemented using specific TSSs. However when distribution is 6292 -- not available (case of Get_PCS_Name = Name_No_DSA), we bypass the 6293 -- generation of these TSSs, and we must keep the RAS type in its 6294 -- original access-to-subprogram form (since all calls through a 6295 -- value of such type will be local anyway in the absence of a PCS). 6296 6297 if Comes_From_Source (N) 6298 and then Is_Remote_Access_To_Subprogram_Type (E) 6299 and then Ekind (E) = E_Access_Subprogram_Type 6300 and then Expander_Active 6301 and then Get_PCS_Name /= Name_No_DSA 6302 then 6303 Rewrite (N, New_Occurrence_Of (Equivalent_Type (E), Sloc (N))); 6304 goto Done; 6305 end if; 6306 6307 -- Set the entity. Note that the reason we call Set_Entity for the 6308 -- overloadable case, as opposed to Set_Entity_With_Checks is 6309 -- that in the overloaded case, the initial call can set the wrong 6310 -- homonym. The call that sets the right homonym is in Sem_Res and 6311 -- that call does use Set_Entity_With_Checks, so we don't miss 6312 -- a style check. 6313 6314 if Is_Overloadable (E) then 6315 Set_Entity (N, E); 6316 else 6317 Set_Entity_With_Checks (N, E); 6318 end if; 6319 6320 if Is_Type (E) then 6321 Set_Etype (N, E); 6322 else 6323 Set_Etype (N, Get_Full_View (Etype (E))); 6324 end if; 6325 6326 if Debug_Flag_E then 6327 Write_Str (" found "); 6328 Write_Entity_Info (E, " "); 6329 end if; 6330 6331 -- If the Ekind of the entity is Void, it means that all homonyms 6332 -- are hidden from all visibility (RM 8.3(5,14-20)). However, this 6333 -- test is skipped if the current scope is a record and the name is 6334 -- a pragma argument expression (case of Atomic and Volatile pragmas 6335 -- and possibly other similar pragmas added later, which are allowed 6336 -- to reference components in the current record). 6337 6338 if Ekind (E) = E_Void 6339 and then 6340 (not Is_Record_Type (Current_Scope) 6341 or else Nkind (Parent (N)) /= N_Pragma_Argument_Association) 6342 then 6343 Premature_Usage (N); 6344 6345 -- If the entity is overloadable, collect all interpretations of the 6346 -- name for subsequent overload resolution. We optimize a bit here to 6347 -- do this only if we have an overloadable entity that is not on its 6348 -- own on the homonym chain. 6349 6350 elsif Is_Overloadable (E) 6351 and then (Present (Homonym (E)) or else Current_Entity (N) /= E) 6352 then 6353 Collect_Interps (N); 6354 6355 -- If no homonyms were visible, the entity is unambiguous 6356 6357 if not Is_Overloaded (N) then 6358 if not Is_Actual_Parameter then 6359 Generate_Reference (E, N); 6360 end if; 6361 end if; 6362 6363 -- Case of non-overloadable entity, set the entity providing that 6364 -- we do not have the case of a discriminant reference within a 6365 -- default expression. Such references are replaced with the 6366 -- corresponding discriminal, which is the formal corresponding to 6367 -- to the discriminant in the initialization procedure. 6368 6369 else 6370 -- Entity is unambiguous, indicate that it is referenced here 6371 6372 -- For a renaming of an object, always generate simple reference, 6373 -- we don't try to keep track of assignments in this case, except 6374 -- in SPARK mode where renamings are traversed for generating 6375 -- local effects of subprograms. 6376 6377 if Is_Object (E) 6378 and then Present (Renamed_Object (E)) 6379 and then not GNATprove_Mode 6380 then 6381 Generate_Reference (E, N); 6382 6383 -- If the renamed entity is a private protected component, 6384 -- reference the original component as well. This needs to be 6385 -- done because the private renamings are installed before any 6386 -- analysis has occurred. Reference to a private component will 6387 -- resolve to the renaming and the original component will be 6388 -- left unreferenced, hence the following. 6389 6390 if Is_Prival (E) then 6391 Generate_Reference (Prival_Link (E), N); 6392 end if; 6393 6394 -- One odd case is that we do not want to set the Referenced flag 6395 -- if the entity is a label, and the identifier is the label in 6396 -- the source, since this is not a reference from the point of 6397 -- view of the user. 6398 6399 elsif Nkind (Parent (N)) = N_Label then 6400 declare 6401 R : constant Boolean := Referenced (E); 6402 6403 begin 6404 -- Generate reference unless this is an actual parameter 6405 -- (see comment below). 6406 6407 if not Is_Actual_Parameter then 6408 Generate_Reference (E, N); 6409 Set_Referenced (E, R); 6410 end if; 6411 end; 6412 6413 -- Normal case, not a label: generate reference 6414 6415 else 6416 if not Is_Actual_Parameter then 6417 6418 -- Package or generic package is always a simple reference 6419 6420 if Is_Package_Or_Generic_Package (E) then 6421 Generate_Reference (E, N, 'r'); 6422 6423 -- Else see if we have a left hand side 6424 6425 else 6426 case Is_LHS (N) is 6427 when Yes => 6428 Generate_Reference (E, N, 'm'); 6429 6430 when No => 6431 Generate_Reference (E, N, 'r'); 6432 6433 -- If we don't know now, generate reference later 6434 6435 when Unknown => 6436 Defer_Reference ((E, N)); 6437 end case; 6438 end if; 6439 end if; 6440 end if; 6441 6442 Set_Entity_Or_Discriminal (N, E); 6443 6444 -- The name may designate a generalized reference, in which case 6445 -- the dereference interpretation will be included. Context is 6446 -- one in which a name is legal. 6447 6448 if Ada_Version >= Ada_2012 6449 and then 6450 (Nkind (Parent (N)) in N_Subexpr 6451 or else Nkind (Parent (N)) in N_Assignment_Statement 6452 | N_Object_Declaration 6453 | N_Parameter_Association) 6454 then 6455 Check_Implicit_Dereference (N, Etype (E)); 6456 end if; 6457 end if; 6458 end; 6459 6460 -- Mark relevant use-type and use-package clauses as effective if the 6461 -- node in question is not overloaded and therefore does not require 6462 -- resolution. 6463 -- 6464 -- Note: Generic actual subprograms do not follow the normal resolution 6465 -- path, so ignore the fact that they are overloaded and mark them 6466 -- anyway. 6467 6468 if Nkind (N) not in N_Subexpr or else not Is_Overloaded (N) then 6469 Mark_Use_Clauses (N); 6470 end if; 6471 6472 -- Come here with entity set 6473 6474 <<Done>> 6475 Check_Restriction_No_Use_Of_Entity (N); 6476 6477 -- Annotate the tree by creating a variable reference marker in case the 6478 -- original variable reference is folded or optimized away. The variable 6479 -- reference marker is automatically saved for later examination by the 6480 -- ABE Processing phase. Variable references which act as actuals in a 6481 -- call require special processing and are left to Resolve_Actuals. The 6482 -- reference is a write when it appears on the left hand side of an 6483 -- assignment. 6484 6485 if Needs_Variable_Reference_Marker (N => N, Calls_OK => False) then 6486 declare 6487 Is_Assignment_LHS : constant Boolean := Is_LHS (N) = Yes; 6488 6489 begin 6490 Build_Variable_Reference_Marker 6491 (N => N, 6492 Read => not Is_Assignment_LHS, 6493 Write => Is_Assignment_LHS); 6494 end; 6495 end if; 6496 end Find_Direct_Name; 6497 6498 ------------------------ 6499 -- Find_Expanded_Name -- 6500 ------------------------ 6501 6502 -- This routine searches the homonym chain of the entity until it finds 6503 -- an entity declared in the scope denoted by the prefix. If the entity 6504 -- is private, it may nevertheless be immediately visible, if we are in 6505 -- the scope of its declaration. 6506 6507 procedure Find_Expanded_Name (N : Node_Id) is 6508 function In_Abstract_View_Pragma (Nod : Node_Id) return Boolean; 6509 -- Determine whether expanded name Nod appears within a pragma which is 6510 -- a suitable context for an abstract view of a state or variable. The 6511 -- following pragmas fall in this category: 6512 -- Depends 6513 -- Global 6514 -- Initializes 6515 -- Refined_Depends 6516 -- Refined_Global 6517 -- 6518 -- In addition, pragma Abstract_State is also considered suitable even 6519 -- though it is an illegal context for an abstract view as this allows 6520 -- for proper resolution of abstract views of variables. This illegal 6521 -- context is later flagged in the analysis of indicator Part_Of. 6522 6523 ----------------------------- 6524 -- In_Abstract_View_Pragma -- 6525 ----------------------------- 6526 6527 function In_Abstract_View_Pragma (Nod : Node_Id) return Boolean is 6528 Par : Node_Id; 6529 6530 begin 6531 -- Climb the parent chain looking for a pragma 6532 6533 Par := Nod; 6534 while Present (Par) loop 6535 if Nkind (Par) = N_Pragma then 6536 if Pragma_Name_Unmapped (Par) 6537 in Name_Abstract_State 6538 | Name_Depends 6539 | Name_Global 6540 | Name_Initializes 6541 | Name_Refined_Depends 6542 | Name_Refined_Global 6543 then 6544 return True; 6545 6546 -- Otherwise the pragma is not a legal context for an abstract 6547 -- view. 6548 6549 else 6550 exit; 6551 end if; 6552 6553 -- Prevent the search from going too far 6554 6555 elsif Is_Body_Or_Package_Declaration (Par) then 6556 exit; 6557 end if; 6558 6559 Par := Parent (Par); 6560 end loop; 6561 6562 return False; 6563 end In_Abstract_View_Pragma; 6564 6565 -- Local variables 6566 6567 Selector : constant Node_Id := Selector_Name (N); 6568 6569 Candidate : Entity_Id := Empty; 6570 P_Name : Entity_Id; 6571 Id : Entity_Id; 6572 6573 -- Start of processing for Find_Expanded_Name 6574 6575 begin 6576 P_Name := Entity (Prefix (N)); 6577 6578 -- If the prefix is a renamed package, look for the entity in the 6579 -- original package. 6580 6581 if Ekind (P_Name) = E_Package 6582 and then Present (Renamed_Entity (P_Name)) 6583 then 6584 P_Name := Renamed_Entity (P_Name); 6585 6586 if From_Limited_With (P_Name) 6587 and then not Unit_Is_Visible (Cunit (Get_Source_Unit (P_Name))) 6588 then 6589 Error_Msg_NE 6590 ("renaming of limited view of package & not usable in this" 6591 & " context (RM 8.5.3(3.1/2))", Prefix (N), P_Name); 6592 6593 elsif Has_Limited_View (P_Name) 6594 and then not Unit_Is_Visible (Cunit (Get_Source_Unit (P_Name))) 6595 and then not Is_Visible_Through_Renamings (P_Name) 6596 then 6597 Error_Msg_NE 6598 ("renaming of limited view of package & not usable in this" 6599 & " context (RM 8.5.3(3.1/2))", Prefix (N), P_Name); 6600 end if; 6601 6602 -- Rewrite node with entity field pointing to renamed object 6603 6604 Rewrite (Prefix (N), New_Copy (Prefix (N))); 6605 Set_Entity (Prefix (N), P_Name); 6606 6607 -- If the prefix is an object of a concurrent type, look for 6608 -- the entity in the associated task or protected type. 6609 6610 elsif Is_Concurrent_Type (Etype (P_Name)) then 6611 P_Name := Etype (P_Name); 6612 end if; 6613 6614 Id := Current_Entity (Selector); 6615 6616 declare 6617 Is_New_Candidate : Boolean; 6618 6619 begin 6620 while Present (Id) loop 6621 if Scope (Id) = P_Name then 6622 Candidate := Id; 6623 Is_New_Candidate := True; 6624 6625 -- Handle abstract views of states and variables. These are 6626 -- acceptable candidates only when the reference to the view 6627 -- appears in certain pragmas. 6628 6629 if Ekind (Id) = E_Abstract_State 6630 and then From_Limited_With (Id) 6631 and then Present (Non_Limited_View (Id)) 6632 then 6633 if In_Abstract_View_Pragma (N) then 6634 Candidate := Non_Limited_View (Id); 6635 Is_New_Candidate := True; 6636 6637 -- Hide the candidate because it is not used in a proper 6638 -- context. 6639 6640 else 6641 Candidate := Empty; 6642 Is_New_Candidate := False; 6643 end if; 6644 end if; 6645 6646 -- Ada 2005 (AI-217): Handle shadow entities associated with 6647 -- types declared in limited-withed nested packages. We don't need 6648 -- to handle E_Incomplete_Subtype entities because the entities 6649 -- in the limited view are always E_Incomplete_Type and 6650 -- E_Class_Wide_Type entities (see Build_Limited_Views). 6651 6652 -- Regarding the expression used to evaluate the scope, it 6653 -- is important to note that the limited view also has shadow 6654 -- entities associated nested packages. For this reason the 6655 -- correct scope of the entity is the scope of the real entity. 6656 -- The non-limited view may itself be incomplete, in which case 6657 -- get the full view if available. 6658 6659 elsif Ekind (Id) in E_Incomplete_Type | E_Class_Wide_Type 6660 and then From_Limited_With (Id) 6661 and then Present (Non_Limited_View (Id)) 6662 and then Scope (Non_Limited_View (Id)) = P_Name 6663 then 6664 Candidate := Get_Full_View (Non_Limited_View (Id)); 6665 Is_New_Candidate := True; 6666 6667 -- Handle special case where the prefix is a renaming of a shadow 6668 -- package which is visible. Required to avoid reporting spurious 6669 -- errors. 6670 6671 elsif Ekind (P_Name) = E_Package 6672 and then From_Limited_With (P_Name) 6673 and then not From_Limited_With (Id) 6674 and then Sloc (Scope (Id)) = Sloc (P_Name) 6675 and then Unit_Is_Visible (Cunit (Get_Source_Unit (P_Name))) 6676 then 6677 Candidate := Get_Full_View (Id); 6678 Is_New_Candidate := True; 6679 6680 -- An unusual case arises with a fully qualified name for an 6681 -- entity local to a generic child unit package, within an 6682 -- instantiation of that package. The name of the unit now 6683 -- denotes the renaming created within the instance. This is 6684 -- only relevant in an instance body, see below. 6685 6686 elsif Is_Generic_Instance (Scope (Id)) 6687 and then In_Open_Scopes (Scope (Id)) 6688 and then In_Instance_Body 6689 and then Ekind (Scope (Id)) = E_Package 6690 and then Ekind (Id) = E_Package 6691 and then Renamed_Entity (Id) = Scope (Id) 6692 and then Is_Immediately_Visible (P_Name) 6693 then 6694 Is_New_Candidate := True; 6695 6696 else 6697 Is_New_Candidate := False; 6698 end if; 6699 6700 if Is_New_Candidate then 6701 6702 -- If entity is a child unit, either it is a visible child of 6703 -- the prefix, or we are in the body of a generic prefix, as 6704 -- will happen when a child unit is instantiated in the body 6705 -- of a generic parent. This is because the instance body does 6706 -- not restore the full compilation context, given that all 6707 -- non-local references have been captured. 6708 6709 if Is_Child_Unit (Id) or else P_Name = Standard_Standard then 6710 exit when Is_Visible_Lib_Unit (Id) 6711 or else (Is_Child_Unit (Id) 6712 and then In_Open_Scopes (Scope (Id)) 6713 and then In_Instance_Body); 6714 else 6715 exit when not Is_Hidden (Id); 6716 end if; 6717 6718 exit when Is_Immediately_Visible (Id); 6719 end if; 6720 6721 Id := Homonym (Id); 6722 end loop; 6723 end; 6724 6725 if No (Id) 6726 and then Ekind (P_Name) in E_Procedure | E_Function 6727 and then Is_Generic_Instance (P_Name) 6728 then 6729 -- Expanded name denotes entity in (instance of) generic subprogram. 6730 -- The entity may be in the subprogram instance, or may denote one of 6731 -- the formals, which is declared in the enclosing wrapper package. 6732 6733 P_Name := Scope (P_Name); 6734 6735 Id := Current_Entity (Selector); 6736 while Present (Id) loop 6737 exit when Scope (Id) = P_Name; 6738 Id := Homonym (Id); 6739 end loop; 6740 end if; 6741 6742 if No (Id) or else Chars (Id) /= Chars (Selector) then 6743 Set_Etype (N, Any_Type); 6744 6745 -- If we are looking for an entity defined in System, try to find it 6746 -- in the child package that may have been provided as an extension 6747 -- to System. The Extend_System pragma will have supplied the name of 6748 -- the extension, which may have to be loaded. 6749 6750 if Chars (P_Name) = Name_System 6751 and then Scope (P_Name) = Standard_Standard 6752 and then Present (System_Extend_Unit) 6753 and then Present_System_Aux (N) 6754 then 6755 Set_Entity (Prefix (N), System_Aux_Id); 6756 Find_Expanded_Name (N); 6757 return; 6758 6759 -- There is an implicit instance of the predefined operator in 6760 -- the given scope. The operator entity is defined in Standard. 6761 -- Has_Implicit_Operator makes the node into an Expanded_Name. 6762 6763 elsif Nkind (Selector) = N_Operator_Symbol 6764 and then Has_Implicit_Operator (N) 6765 then 6766 return; 6767 6768 -- If there is no literal defined in the scope denoted by the 6769 -- prefix, the literal may belong to (a type derived from) 6770 -- Standard_Character, for which we have no explicit literals. 6771 6772 elsif Nkind (Selector) = N_Character_Literal 6773 and then Has_Implicit_Character_Literal (N) 6774 then 6775 return; 6776 6777 else 6778 -- If the prefix is a single concurrent object, use its name in 6779 -- the error message, rather than that of the anonymous type. 6780 6781 if Is_Concurrent_Type (P_Name) 6782 and then Is_Internal_Name (Chars (P_Name)) 6783 then 6784 Error_Msg_Node_2 := Entity (Prefix (N)); 6785 else 6786 Error_Msg_Node_2 := P_Name; 6787 end if; 6788 6789 if P_Name = System_Aux_Id then 6790 P_Name := Scope (P_Name); 6791 Set_Entity (Prefix (N), P_Name); 6792 end if; 6793 6794 if Present (Candidate) then 6795 6796 -- If we know that the unit is a child unit we can give a more 6797 -- accurate error message. 6798 6799 if Is_Child_Unit (Candidate) then 6800 6801 -- If the candidate is a private child unit and we are in 6802 -- the visible part of a public unit, specialize the error 6803 -- message. There might be a private with_clause for it, 6804 -- but it is not currently active. 6805 6806 if Is_Private_Descendant (Candidate) 6807 and then Ekind (Current_Scope) = E_Package 6808 and then not In_Private_Part (Current_Scope) 6809 and then not Is_Private_Descendant (Current_Scope) 6810 then 6811 Error_Msg_N 6812 ("private child unit& is not visible here", Selector); 6813 6814 -- Normal case where we have a missing with for a child unit 6815 6816 else 6817 Error_Msg_Qual_Level := 99; 6818 Error_Msg_NE -- CODEFIX 6819 ("missing `WITH &;`", Selector, Candidate); 6820 Error_Msg_Qual_Level := 0; 6821 end if; 6822 6823 -- Here we don't know that this is a child unit 6824 6825 else 6826 Error_Msg_NE ("& is not a visible entity of&", N, Selector); 6827 end if; 6828 6829 else 6830 -- Within the instantiation of a child unit, the prefix may 6831 -- denote the parent instance, but the selector has the name 6832 -- of the original child. That is to say, when A.B appears 6833 -- within an instantiation of generic child unit B, the scope 6834 -- stack includes an instance of A (P_Name) and an instance 6835 -- of B under some other name. We scan the scope to find this 6836 -- child instance, which is the desired entity. 6837 -- Note that the parent may itself be a child instance, if 6838 -- the reference is of the form A.B.C, in which case A.B has 6839 -- already been rewritten with the proper entity. 6840 6841 if In_Open_Scopes (P_Name) 6842 and then Is_Generic_Instance (P_Name) 6843 then 6844 declare 6845 Gen_Par : constant Entity_Id := 6846 Generic_Parent (Specification 6847 (Unit_Declaration_Node (P_Name))); 6848 S : Entity_Id := Current_Scope; 6849 P : Entity_Id; 6850 6851 begin 6852 for J in reverse 0 .. Scope_Stack.Last loop 6853 S := Scope_Stack.Table (J).Entity; 6854 6855 exit when S = Standard_Standard; 6856 6857 if Ekind (S) in E_Function | E_Package | E_Procedure 6858 then 6859 P := 6860 Generic_Parent (Specification 6861 (Unit_Declaration_Node (S))); 6862 6863 -- Check that P is a generic child of the generic 6864 -- parent of the prefix. 6865 6866 if Present (P) 6867 and then Chars (P) = Chars (Selector) 6868 and then Scope (P) = Gen_Par 6869 then 6870 Id := S; 6871 goto Found; 6872 end if; 6873 end if; 6874 6875 end loop; 6876 end; 6877 end if; 6878 6879 -- If this is a selection from Ada, System or Interfaces, then 6880 -- we assume a missing with for the corresponding package. 6881 6882 if Is_Known_Unit (N) 6883 and then not (Present (Entity (Prefix (N))) 6884 and then Scope (Entity (Prefix (N))) /= 6885 Standard_Standard) 6886 then 6887 if not Error_Posted (N) then 6888 Error_Msg_Node_2 := Selector; 6889 Error_Msg_N -- CODEFIX 6890 ("missing `WITH &.&;`", Prefix (N)); 6891 end if; 6892 6893 -- If this is a selection from a dummy package, then suppress 6894 -- the error message, of course the entity is missing if the 6895 -- package is missing. 6896 6897 elsif Sloc (Error_Msg_Node_2) = No_Location then 6898 null; 6899 6900 -- Here we have the case of an undefined component 6901 6902 else 6903 -- The prefix may hide a homonym in the context that 6904 -- declares the desired entity. This error can use a 6905 -- specialized message. 6906 6907 if In_Open_Scopes (P_Name) then 6908 declare 6909 H : constant Entity_Id := Homonym (P_Name); 6910 6911 begin 6912 if Present (H) 6913 and then Is_Compilation_Unit (H) 6914 and then 6915 (Is_Immediately_Visible (H) 6916 or else Is_Visible_Lib_Unit (H)) 6917 then 6918 Id := First_Entity (H); 6919 while Present (Id) loop 6920 if Chars (Id) = Chars (Selector) then 6921 Error_Msg_Qual_Level := 99; 6922 Error_Msg_Name_1 := Chars (Selector); 6923 Error_Msg_NE 6924 ("% not declared in&", N, P_Name); 6925 Error_Msg_NE 6926 ("\use fully qualified name starting with " 6927 & "Standard to make& visible", N, H); 6928 Error_Msg_Qual_Level := 0; 6929 goto Done; 6930 end if; 6931 6932 Next_Entity (Id); 6933 end loop; 6934 end if; 6935 6936 -- If not found, standard error message 6937 6938 Error_Msg_NE ("& not declared in&", N, Selector); 6939 6940 <<Done>> null; 6941 end; 6942 6943 else 6944 -- Might be worth specializing the case when the prefix 6945 -- is a limited view. 6946 -- ... not declared in limited view of... 6947 6948 Error_Msg_NE ("& not declared in&", N, Selector); 6949 end if; 6950 6951 -- Check for misspelling of some entity in prefix 6952 6953 Id := First_Entity (P_Name); 6954 while Present (Id) loop 6955 if Is_Bad_Spelling_Of (Chars (Id), Chars (Selector)) 6956 and then not Is_Internal_Name (Chars (Id)) 6957 then 6958 Error_Msg_NE -- CODEFIX 6959 ("possible misspelling of&", Selector, Id); 6960 exit; 6961 end if; 6962 6963 Next_Entity (Id); 6964 end loop; 6965 6966 -- Specialize the message if this may be an instantiation 6967 -- of a child unit that was not mentioned in the context. 6968 6969 if Nkind (Parent (N)) = N_Package_Instantiation 6970 and then Is_Generic_Instance (Entity (Prefix (N))) 6971 and then Is_Compilation_Unit 6972 (Generic_Parent (Parent (Entity (Prefix (N))))) 6973 then 6974 Error_Msg_Node_2 := Selector; 6975 Error_Msg_N -- CODEFIX 6976 ("\missing `WITH &.&;`", Prefix (N)); 6977 end if; 6978 end if; 6979 end if; 6980 6981 Id := Any_Id; 6982 end if; 6983 end if; 6984 6985 <<Found>> 6986 if Comes_From_Source (N) 6987 and then Is_Remote_Access_To_Subprogram_Type (Id) 6988 and then Ekind (Id) = E_Access_Subprogram_Type 6989 and then Present (Equivalent_Type (Id)) 6990 then 6991 -- If we are not actually generating distribution code (i.e. the 6992 -- current PCS is the dummy non-distributed version), then the 6993 -- Equivalent_Type will be missing, and Id should be treated as 6994 -- a regular access-to-subprogram type. 6995 6996 Id := Equivalent_Type (Id); 6997 Set_Chars (Selector, Chars (Id)); 6998 end if; 6999 7000 -- Ada 2005 (AI-50217): Check usage of entities in limited withed units 7001 7002 if Ekind (P_Name) = E_Package and then From_Limited_With (P_Name) then 7003 if From_Limited_With (Id) 7004 or else Is_Type (Id) 7005 or else Ekind (Id) = E_Package 7006 then 7007 null; 7008 else 7009 Error_Msg_N 7010 ("limited withed package can only be used to access incomplete " 7011 & "types", N); 7012 end if; 7013 end if; 7014 7015 if Is_Task_Type (P_Name) 7016 and then ((Ekind (Id) = E_Entry 7017 and then Nkind (Parent (N)) /= N_Attribute_Reference) 7018 or else 7019 (Ekind (Id) = E_Entry_Family 7020 and then 7021 Nkind (Parent (Parent (N))) /= N_Attribute_Reference)) 7022 then 7023 -- If both the task type and the entry are in scope, this may still 7024 -- be the expanded name of an entry formal. 7025 7026 if In_Open_Scopes (Id) 7027 and then Nkind (Parent (N)) = N_Selected_Component 7028 then 7029 null; 7030 7031 else 7032 -- It is an entry call after all, either to the current task 7033 -- (which will deadlock) or to an enclosing task. 7034 7035 Analyze_Selected_Component (N); 7036 return; 7037 end if; 7038 end if; 7039 7040 case Nkind (N) is 7041 when N_Selected_Component => 7042 Reinit_Field_To_Zero (N, F_Is_Prefixed_Call); 7043 Change_Selected_Component_To_Expanded_Name (N); 7044 7045 when N_Expanded_Name => 7046 null; 7047 7048 when others => 7049 pragma Assert (False); 7050 end case; 7051 7052 -- Preserve relevant elaboration-related attributes of the context which 7053 -- are no longer available or very expensive to recompute once analysis, 7054 -- resolution, and expansion are over. 7055 7056 Mark_Elaboration_Attributes 7057 (N_Id => N, 7058 Checks => True, 7059 Modes => True, 7060 Warnings => True); 7061 7062 -- Set appropriate type 7063 7064 if Is_Type (Id) then 7065 Set_Etype (N, Id); 7066 else 7067 Set_Etype (N, Get_Full_View (Etype (Id))); 7068 end if; 7069 7070 -- Do style check and generate reference, but skip both steps if this 7071 -- entity has homonyms, since we may not have the right homonym set yet. 7072 -- The proper homonym will be set during the resolve phase. 7073 7074 if Has_Homonym (Id) then 7075 Set_Entity (N, Id); 7076 7077 else 7078 Set_Entity_Or_Discriminal (N, Id); 7079 7080 case Is_LHS (N) is 7081 when Yes => 7082 Generate_Reference (Id, N, 'm'); 7083 7084 when No => 7085 Generate_Reference (Id, N, 'r'); 7086 7087 when Unknown => 7088 Defer_Reference ((Id, N)); 7089 end case; 7090 end if; 7091 7092 -- Check for violation of No_Wide_Characters 7093 7094 Check_Wide_Character_Restriction (Id, N); 7095 7096 -- If the Ekind of the entity is Void, it means that all homonyms are 7097 -- hidden from all visibility (RM 8.3(5,14-20)). 7098 7099 if Ekind (Id) = E_Void then 7100 Premature_Usage (N); 7101 7102 elsif Is_Overloadable (Id) and then Present (Homonym (Id)) then 7103 declare 7104 H : Entity_Id := Homonym (Id); 7105 7106 begin 7107 while Present (H) loop 7108 if Scope (H) = Scope (Id) 7109 and then (not Is_Hidden (H) 7110 or else Is_Immediately_Visible (H)) 7111 then 7112 Collect_Interps (N); 7113 exit; 7114 end if; 7115 7116 H := Homonym (H); 7117 end loop; 7118 7119 -- If an extension of System is present, collect possible explicit 7120 -- overloadings declared in the extension. 7121 7122 if Chars (P_Name) = Name_System 7123 and then Scope (P_Name) = Standard_Standard 7124 and then Present (System_Extend_Unit) 7125 and then Present_System_Aux (N) 7126 then 7127 H := Current_Entity (Id); 7128 7129 while Present (H) loop 7130 if Scope (H) = System_Aux_Id then 7131 Add_One_Interp (N, H, Etype (H)); 7132 end if; 7133 7134 H := Homonym (H); 7135 end loop; 7136 end if; 7137 end; 7138 end if; 7139 7140 if Nkind (Selector_Name (N)) = N_Operator_Symbol 7141 and then Scope (Id) /= Standard_Standard 7142 then 7143 -- In addition to user-defined operators in the given scope, there 7144 -- may be an implicit instance of the predefined operator. The 7145 -- operator (defined in Standard) is found in Has_Implicit_Operator, 7146 -- and added to the interpretations. Procedure Add_One_Interp will 7147 -- determine which hides which. 7148 7149 if Has_Implicit_Operator (N) then 7150 null; 7151 end if; 7152 end if; 7153 7154 -- If there is a single interpretation for N we can generate a 7155 -- reference to the unique entity found. 7156 7157 if Is_Overloadable (Id) and then not Is_Overloaded (N) then 7158 Generate_Reference (Id, N); 7159 end if; 7160 7161 -- Mark relevant use-type and use-package clauses as effective if the 7162 -- node in question is not overloaded and therefore does not require 7163 -- resolution. 7164 7165 if Nkind (N) not in N_Subexpr or else not Is_Overloaded (N) then 7166 Mark_Use_Clauses (N); 7167 end if; 7168 7169 Check_Restriction_No_Use_Of_Entity (N); 7170 7171 -- Annotate the tree by creating a variable reference marker in case the 7172 -- original variable reference is folded or optimized away. The variable 7173 -- reference marker is automatically saved for later examination by the 7174 -- ABE Processing phase. Variable references which act as actuals in a 7175 -- call require special processing and are left to Resolve_Actuals. The 7176 -- reference is a write when it appears on the left hand side of an 7177 -- assignment. 7178 7179 if Needs_Variable_Reference_Marker 7180 (N => N, 7181 Calls_OK => False) 7182 then 7183 declare 7184 Is_Assignment_LHS : constant Boolean := Is_LHS (N) = Yes; 7185 7186 begin 7187 Build_Variable_Reference_Marker 7188 (N => N, 7189 Read => not Is_Assignment_LHS, 7190 Write => Is_Assignment_LHS); 7191 end; 7192 end if; 7193 end Find_Expanded_Name; 7194 7195 -------------------- 7196 -- Find_First_Use -- 7197 -------------------- 7198 7199 function Find_First_Use (Use_Clause : Node_Id) return Node_Id is 7200 Curr : Node_Id; 7201 7202 begin 7203 -- Loop through the Prev_Use_Clause chain 7204 7205 Curr := Use_Clause; 7206 while Present (Prev_Use_Clause (Curr)) loop 7207 Curr := Prev_Use_Clause (Curr); 7208 end loop; 7209 7210 return Curr; 7211 end Find_First_Use; 7212 7213 ------------------------- 7214 -- Find_Renamed_Entity -- 7215 ------------------------- 7216 7217 function Find_Renamed_Entity 7218 (N : Node_Id; 7219 Nam : Node_Id; 7220 New_S : Entity_Id; 7221 Is_Actual : Boolean := False) return Entity_Id 7222 is 7223 Ind : Interp_Index; 7224 I1 : Interp_Index := 0; -- Suppress junk warnings 7225 It : Interp; 7226 It1 : Interp; 7227 Old_S : Entity_Id; 7228 Inst : Entity_Id; 7229 7230 function Find_Nearer_Entity 7231 (New_S : Entity_Id; 7232 Old1_S : Entity_Id; 7233 Old2_S : Entity_Id) return Entity_Id; 7234 -- Determine whether one of Old_S1 and Old_S2 is nearer to New_S than 7235 -- the other, and return it if so. Return Empty otherwise. We use this 7236 -- in conjunction with Inherit_Renamed_Profile to simplify later type 7237 -- disambiguation for actual subprograms in instances. 7238 7239 function Is_Visible_Operation (Op : Entity_Id) return Boolean; 7240 -- If the renamed entity is an implicit operator, check whether it is 7241 -- visible because its operand type is properly visible. This check 7242 -- applies to explicit renamed entities that appear in the source in a 7243 -- renaming declaration or a formal subprogram instance, but not to 7244 -- default generic actuals with a name. 7245 7246 function Report_Overload return Entity_Id; 7247 -- List possible interpretations, and specialize message in the 7248 -- case of a generic actual. 7249 7250 function Within (Inner, Outer : Entity_Id) return Boolean; 7251 -- Determine whether a candidate subprogram is defined within the 7252 -- enclosing instance. If yes, it has precedence over outer candidates. 7253 7254 -------------------------- 7255 -- Find_Nearer_Entity -- 7256 -------------------------- 7257 7258 function Find_Nearer_Entity 7259 (New_S : Entity_Id; 7260 Old1_S : Entity_Id; 7261 Old2_S : Entity_Id) return Entity_Id 7262 is 7263 New_F : Entity_Id; 7264 Old1_F : Entity_Id; 7265 Old2_F : Entity_Id; 7266 Anc_T : Entity_Id; 7267 7268 begin 7269 New_F := First_Formal (New_S); 7270 Old1_F := First_Formal (Old1_S); 7271 Old2_F := First_Formal (Old2_S); 7272 7273 -- The criterion is whether the type of the formals of one of Old1_S 7274 -- and Old2_S is an ancestor subtype of the type of the corresponding 7275 -- formals of New_S while the other is not (we already know that they 7276 -- are all subtypes of the same base type). 7277 7278 -- This makes it possible to find the more correct renamed entity in 7279 -- the case of a generic instantiation nested in an enclosing one for 7280 -- which different formal types get the same actual type, which will 7281 -- in turn make it possible for Inherit_Renamed_Profile to preserve 7282 -- types on formal parameters and ultimately simplify disambiguation. 7283 7284 -- Consider the follow package G: 7285 7286 -- generic 7287 -- type Item_T is private; 7288 -- with function Compare (L, R: Item_T) return Boolean is <>; 7289 7290 -- type Bound_T is private; 7291 -- with function Compare (L, R : Bound_T) return Boolean is <>; 7292 -- package G is 7293 -- ... 7294 -- end G; 7295 7296 -- package body G is 7297 -- package My_Inner is Inner_G (Bound_T); 7298 -- ... 7299 -- end G; 7300 7301 -- with the following package Inner_G: 7302 7303 -- generic 7304 -- type T is private; 7305 -- with function Compare (L, R: T) return Boolean is <>; 7306 -- package Inner_G is 7307 -- function "<" (L, R: T) return Boolean is (Compare (L, R)); 7308 -- end Inner_G; 7309 7310 -- If G is instantiated on the same actual type with a single Compare 7311 -- function: 7312 7313 -- type T is ... 7314 -- function Compare (L, R : T) return Boolean; 7315 -- package My_G is new (T, T); 7316 7317 -- then the renaming generated for Compare in the inner instantiation 7318 -- is ambiguous: it can rename either of the renamings generated for 7319 -- the outer instantiation. Now if the first one is picked up, then 7320 -- the subtypes of the formal parameters of the renaming will not be 7321 -- preserved in Inherit_Renamed_Profile because they are subtypes of 7322 -- the Bound_T formal type and not of the Item_T formal type, so we 7323 -- need to arrange for the second one to be picked up instead. 7324 7325 while Present (New_F) loop 7326 if Etype (Old1_F) /= Etype (Old2_F) then 7327 Anc_T := Ancestor_Subtype (Etype (New_F)); 7328 7329 if Etype (Old1_F) = Anc_T then 7330 return Old1_S; 7331 elsif Etype (Old2_F) = Anc_T then 7332 return Old2_S; 7333 end if; 7334 end if; 7335 7336 Next_Formal (New_F); 7337 Next_Formal (Old1_F); 7338 Next_Formal (Old2_F); 7339 end loop; 7340 7341 pragma Assert (No (Old1_F)); 7342 pragma Assert (No (Old2_F)); 7343 7344 return Empty; 7345 end Find_Nearer_Entity; 7346 7347 -------------------------- 7348 -- Is_Visible_Operation -- 7349 -------------------------- 7350 7351 function Is_Visible_Operation (Op : Entity_Id) return Boolean is 7352 Scop : Entity_Id; 7353 Typ : Entity_Id; 7354 Btyp : Entity_Id; 7355 7356 begin 7357 if Ekind (Op) /= E_Operator 7358 or else Scope (Op) /= Standard_Standard 7359 or else (In_Instance 7360 and then (not Is_Actual 7361 or else Present (Enclosing_Instance))) 7362 then 7363 return True; 7364 7365 else 7366 -- For a fixed point type operator, check the resulting type, 7367 -- because it may be a mixed mode integer * fixed operation. 7368 7369 if Present (Next_Formal (First_Formal (New_S))) 7370 and then Is_Fixed_Point_Type (Etype (New_S)) 7371 then 7372 Typ := Etype (New_S); 7373 else 7374 Typ := Etype (First_Formal (New_S)); 7375 end if; 7376 7377 Btyp := Base_Type (Typ); 7378 7379 if Nkind (Nam) /= N_Expanded_Name then 7380 return (In_Open_Scopes (Scope (Btyp)) 7381 or else Is_Potentially_Use_Visible (Btyp) 7382 or else In_Use (Btyp) 7383 or else In_Use (Scope (Btyp))); 7384 7385 else 7386 Scop := Entity (Prefix (Nam)); 7387 7388 if Ekind (Scop) = E_Package 7389 and then Present (Renamed_Entity (Scop)) 7390 then 7391 Scop := Renamed_Entity (Scop); 7392 end if; 7393 7394 -- Operator is visible if prefix of expanded name denotes 7395 -- scope of type, or else type is defined in System_Aux 7396 -- and the prefix denotes System. 7397 7398 return Scope (Btyp) = Scop 7399 or else (Scope (Btyp) = System_Aux_Id 7400 and then Scope (Scope (Btyp)) = Scop); 7401 end if; 7402 end if; 7403 end Is_Visible_Operation; 7404 7405 ------------ 7406 -- Within -- 7407 ------------ 7408 7409 function Within (Inner, Outer : Entity_Id) return Boolean is 7410 Sc : Entity_Id; 7411 7412 begin 7413 Sc := Scope (Inner); 7414 while Sc /= Standard_Standard loop 7415 if Sc = Outer then 7416 return True; 7417 else 7418 Sc := Scope (Sc); 7419 end if; 7420 end loop; 7421 7422 return False; 7423 end Within; 7424 7425 --------------------- 7426 -- Report_Overload -- 7427 --------------------- 7428 7429 function Report_Overload return Entity_Id is 7430 begin 7431 if Is_Actual then 7432 Error_Msg_NE -- CODEFIX 7433 ("ambiguous actual subprogram&, " & 7434 "possible interpretations:", N, Nam); 7435 else 7436 Error_Msg_N -- CODEFIX 7437 ("ambiguous subprogram, " & 7438 "possible interpretations:", N); 7439 end if; 7440 7441 List_Interps (Nam, N); 7442 return Old_S; 7443 end Report_Overload; 7444 7445 -- Start of processing for Find_Renamed_Entity 7446 7447 begin 7448 Old_S := Any_Id; 7449 Candidate_Renaming := Empty; 7450 7451 if Is_Overloaded (Nam) then 7452 Get_First_Interp (Nam, Ind, It); 7453 while Present (It.Nam) loop 7454 if Entity_Matches_Spec (It.Nam, New_S) 7455 and then Is_Visible_Operation (It.Nam) 7456 then 7457 if Old_S /= Any_Id then 7458 7459 -- Note: The call to Disambiguate only happens if a 7460 -- previous interpretation was found, in which case I1 7461 -- has received a value. 7462 7463 It1 := Disambiguate (Nam, I1, Ind, Etype (Old_S)); 7464 7465 if It1 = No_Interp then 7466 Inst := Enclosing_Instance; 7467 7468 if Present (Inst) then 7469 if Within (It.Nam, Inst) then 7470 if Within (Old_S, Inst) then 7471 declare 7472 It_D : constant Uint := 7473 Scope_Depth_Default_0 (It.Nam); 7474 Old_D : constant Uint := 7475 Scope_Depth_Default_0 (Old_S); 7476 N_Ent : Entity_Id; 7477 begin 7478 -- Choose the innermost subprogram, which 7479 -- would hide the outer one in the generic. 7480 7481 if Old_D > It_D then 7482 return Old_S; 7483 elsif It_D > Old_D then 7484 return It.Nam; 7485 end if; 7486 7487 -- Otherwise, if we can determine that one 7488 -- of the entities is nearer to the renaming 7489 -- than the other, choose it. If not, then 7490 -- return the newer one as done historically. 7491 7492 N_Ent := 7493 Find_Nearer_Entity (New_S, Old_S, It.Nam); 7494 if Present (N_Ent) then 7495 return N_Ent; 7496 else 7497 return It.Nam; 7498 end if; 7499 end; 7500 end if; 7501 7502 elsif Within (Old_S, Inst) then 7503 return Old_S; 7504 7505 else 7506 return Report_Overload; 7507 end if; 7508 7509 -- If not within an instance, ambiguity is real 7510 7511 else 7512 return Report_Overload; 7513 end if; 7514 7515 else 7516 Old_S := It1.Nam; 7517 exit; 7518 end if; 7519 7520 else 7521 I1 := Ind; 7522 Old_S := It.Nam; 7523 end if; 7524 7525 elsif 7526 Present (First_Formal (It.Nam)) 7527 and then Present (First_Formal (New_S)) 7528 and then (Base_Type (Etype (First_Formal (It.Nam))) = 7529 Base_Type (Etype (First_Formal (New_S)))) 7530 then 7531 Candidate_Renaming := It.Nam; 7532 end if; 7533 7534 Get_Next_Interp (Ind, It); 7535 end loop; 7536 7537 Set_Entity (Nam, Old_S); 7538 7539 if Old_S /= Any_Id then 7540 Set_Is_Overloaded (Nam, False); 7541 end if; 7542 7543 -- Non-overloaded case 7544 7545 else 7546 if Is_Actual 7547 and then Present (Enclosing_Instance) 7548 and then Entity_Matches_Spec (Entity (Nam), New_S) 7549 then 7550 Old_S := Entity (Nam); 7551 7552 elsif Entity_Matches_Spec (Entity (Nam), New_S) then 7553 Candidate_Renaming := New_S; 7554 7555 if Is_Visible_Operation (Entity (Nam)) then 7556 Old_S := Entity (Nam); 7557 end if; 7558 7559 elsif Present (First_Formal (Entity (Nam))) 7560 and then Present (First_Formal (New_S)) 7561 and then (Base_Type (Etype (First_Formal (Entity (Nam)))) = 7562 Base_Type (Etype (First_Formal (New_S)))) 7563 then 7564 Candidate_Renaming := Entity (Nam); 7565 end if; 7566 end if; 7567 7568 return Old_S; 7569 end Find_Renamed_Entity; 7570 7571 ----------------------------- 7572 -- Find_Selected_Component -- 7573 ----------------------------- 7574 7575 procedure Find_Selected_Component (N : Node_Id) is 7576 P : constant Node_Id := Prefix (N); 7577 7578 P_Name : Entity_Id; 7579 -- Entity denoted by prefix 7580 7581 P_Type : Entity_Id; 7582 -- and its type 7583 7584 Nam : Node_Id; 7585 7586 function Available_Subtype return Boolean; 7587 -- A small optimization: if the prefix is constrained and the component 7588 -- is an array type we may already have a usable subtype for it, so we 7589 -- can use it rather than generating a new one, because the bounds 7590 -- will be the values of the discriminants and not discriminant refs. 7591 -- This simplifies value tracing in GNATprove. For consistency, both 7592 -- the entity name and the subtype come from the constrained component. 7593 7594 -- This is only used in GNATprove mode: when generating code it may be 7595 -- necessary to create an itype in the scope of use of the selected 7596 -- component, e.g. in the context of a expanded record equality. 7597 7598 function Is_Reference_In_Subunit return Boolean; 7599 -- In a subunit, the scope depth is not a proper measure of hiding, 7600 -- because the context of the proper body may itself hide entities in 7601 -- parent units. This rare case requires inspecting the tree directly 7602 -- because the proper body is inserted in the main unit and its context 7603 -- is simply added to that of the parent. 7604 7605 ----------------------- 7606 -- Available_Subtype -- 7607 ----------------------- 7608 7609 function Available_Subtype return Boolean is 7610 Comp : Entity_Id; 7611 7612 begin 7613 if GNATprove_Mode then 7614 Comp := First_Entity (Etype (P)); 7615 while Present (Comp) loop 7616 if Chars (Comp) = Chars (Selector_Name (N)) then 7617 Set_Etype (N, Etype (Comp)); 7618 Set_Entity (Selector_Name (N), Comp); 7619 Set_Etype (Selector_Name (N), Etype (Comp)); 7620 return True; 7621 end if; 7622 7623 Next_Component (Comp); 7624 end loop; 7625 end if; 7626 7627 return False; 7628 end Available_Subtype; 7629 7630 ----------------------------- 7631 -- Is_Reference_In_Subunit -- 7632 ----------------------------- 7633 7634 function Is_Reference_In_Subunit return Boolean is 7635 Clause : Node_Id; 7636 Comp_Unit : Node_Id; 7637 7638 begin 7639 Comp_Unit := N; 7640 while Present (Comp_Unit) 7641 and then Nkind (Comp_Unit) /= N_Compilation_Unit 7642 loop 7643 Comp_Unit := Parent (Comp_Unit); 7644 end loop; 7645 7646 if No (Comp_Unit) or else Nkind (Unit (Comp_Unit)) /= N_Subunit then 7647 return False; 7648 end if; 7649 7650 -- Now check whether the package is in the context of the subunit 7651 7652 Clause := First (Context_Items (Comp_Unit)); 7653 while Present (Clause) loop 7654 if Nkind (Clause) = N_With_Clause 7655 and then Entity (Name (Clause)) = P_Name 7656 then 7657 return True; 7658 end if; 7659 7660 Next (Clause); 7661 end loop; 7662 7663 return False; 7664 end Is_Reference_In_Subunit; 7665 7666 -- Start of processing for Find_Selected_Component 7667 7668 begin 7669 Analyze (P); 7670 7671 if Nkind (P) = N_Error then 7672 return; 7673 end if; 7674 7675 -- If the selector already has an entity, the node has been constructed 7676 -- in the course of expansion, and is known to be valid. Do not verify 7677 -- that it is defined for the type (it may be a private component used 7678 -- in the expansion of record equality). 7679 7680 if Present (Entity (Selector_Name (N))) then 7681 if No (Etype (N)) or else Etype (N) = Any_Type then 7682 declare 7683 Sel_Name : constant Node_Id := Selector_Name (N); 7684 Selector : constant Entity_Id := Entity (Sel_Name); 7685 C_Etype : Node_Id; 7686 7687 begin 7688 Set_Etype (Sel_Name, Etype (Selector)); 7689 7690 if not Is_Entity_Name (P) then 7691 Resolve (P); 7692 end if; 7693 7694 -- Build an actual subtype except for the first parameter 7695 -- of an init proc, where this actual subtype is by 7696 -- definition incorrect, since the object is uninitialized 7697 -- (and does not even have defined discriminants etc.) 7698 7699 if Is_Entity_Name (P) 7700 and then Ekind (Entity (P)) = E_Function 7701 then 7702 Nam := New_Copy (P); 7703 7704 if Is_Overloaded (P) then 7705 Save_Interps (P, Nam); 7706 end if; 7707 7708 Rewrite (P, Make_Function_Call (Sloc (P), Name => Nam)); 7709 Analyze_Call (P); 7710 Analyze_Selected_Component (N); 7711 return; 7712 7713 elsif Ekind (Selector) = E_Component 7714 and then (not Is_Entity_Name (P) 7715 or else Chars (Entity (P)) /= Name_uInit) 7716 then 7717 -- Check if we already have an available subtype we can use 7718 7719 if Ekind (Etype (P)) = E_Record_Subtype 7720 and then Nkind (Parent (Etype (P))) = N_Subtype_Declaration 7721 and then Is_Array_Type (Etype (Selector)) 7722 and then not Is_Packed (Etype (Selector)) 7723 and then Available_Subtype 7724 then 7725 return; 7726 7727 -- Do not build the subtype when referencing components of 7728 -- dispatch table wrappers. Required to avoid generating 7729 -- elaboration code with HI runtimes. 7730 7731 elsif Is_RTE (Scope (Selector), RE_Dispatch_Table_Wrapper) 7732 or else 7733 Is_RTE (Scope (Selector), RE_No_Dispatch_Table_Wrapper) 7734 then 7735 C_Etype := Empty; 7736 else 7737 C_Etype := 7738 Build_Actual_Subtype_Of_Component 7739 (Etype (Selector), N); 7740 end if; 7741 7742 else 7743 C_Etype := Empty; 7744 end if; 7745 7746 if No (C_Etype) then 7747 C_Etype := Etype (Selector); 7748 else 7749 Insert_Action (N, C_Etype); 7750 C_Etype := Defining_Identifier (C_Etype); 7751 end if; 7752 7753 Set_Etype (N, C_Etype); 7754 end; 7755 7756 -- If the selected component appears within a default expression 7757 -- and it has an actual subtype, the preanalysis has not yet 7758 -- completed its analysis, because Insert_Actions is disabled in 7759 -- that context. Within the init proc of the enclosing type we 7760 -- must complete this analysis, if an actual subtype was created. 7761 7762 elsif Inside_Init_Proc then 7763 declare 7764 Typ : constant Entity_Id := Etype (N); 7765 Decl : constant Node_Id := Declaration_Node (Typ); 7766 begin 7767 if Nkind (Decl) = N_Subtype_Declaration 7768 and then not Analyzed (Decl) 7769 and then Is_List_Member (Decl) 7770 and then No (Parent (Decl)) 7771 then 7772 Remove (Decl); 7773 Insert_Action (N, Decl); 7774 end if; 7775 end; 7776 end if; 7777 7778 return; 7779 7780 elsif Is_Entity_Name (P) then 7781 P_Name := Entity (P); 7782 7783 -- The prefix may denote an enclosing type which is the completion 7784 -- of an incomplete type declaration. 7785 7786 if Is_Type (P_Name) then 7787 Set_Entity (P, Get_Full_View (P_Name)); 7788 Set_Etype (P, Entity (P)); 7789 P_Name := Entity (P); 7790 end if; 7791 7792 P_Type := Base_Type (Etype (P)); 7793 7794 if Debug_Flag_E then 7795 Write_Str ("Found prefix type to be "); 7796 Write_Entity_Info (P_Type, " "); Write_Eol; 7797 end if; 7798 7799 -- If the prefix's type is an access type, get to the record type 7800 7801 if Is_Access_Type (P_Type) then 7802 P_Type := Implicitly_Designated_Type (P_Type); 7803 end if; 7804 7805 -- First check for components of a record object (not the result of 7806 -- a call, which is handled below). This also covers the case where 7807 -- the extension feature that supports the prefixed form of calls 7808 -- for primitives of untagged types is enabled (excluding concurrent 7809 -- cases, which are handled further below). 7810 7811 if Is_Type (P_Type) 7812 and then (Has_Components (P_Type) 7813 or else (Extensions_Allowed 7814 and then not Is_Concurrent_Type (P_Type))) 7815 and then not Is_Overloadable (P_Name) 7816 and then not Is_Type (P_Name) 7817 then 7818 -- Selected component of record. Type checking will validate 7819 -- name of selector. 7820 7821 -- ??? Could we rewrite an implicit dereference into an explicit 7822 -- one here? 7823 7824 Analyze_Selected_Component (N); 7825 7826 -- Reference to type name in predicate/invariant expression 7827 7828 elsif Is_Concurrent_Type (P_Type) 7829 and then not In_Open_Scopes (P_Name) 7830 and then (not Is_Concurrent_Type (Etype (P_Name)) 7831 or else not In_Open_Scopes (Etype (P_Name))) 7832 then 7833 -- Call to protected operation or entry. Type checking is 7834 -- needed on the prefix. 7835 7836 Analyze_Selected_Component (N); 7837 7838 elsif (In_Open_Scopes (P_Name) 7839 and then Ekind (P_Name) /= E_Void 7840 and then not Is_Overloadable (P_Name)) 7841 or else (Is_Concurrent_Type (Etype (P_Name)) 7842 and then In_Open_Scopes (Etype (P_Name))) 7843 then 7844 -- Prefix denotes an enclosing loop, block, or task, i.e. an 7845 -- enclosing construct that is not a subprogram or accept. 7846 7847 -- A special case: a protected body may call an operation 7848 -- on an external object of the same type, in which case it 7849 -- is not an expanded name. If the prefix is the type itself, 7850 -- or the context is a single synchronized object it can only 7851 -- be interpreted as an expanded name. 7852 7853 if Is_Concurrent_Type (Etype (P_Name)) then 7854 if Is_Type (P_Name) 7855 or else Present (Anonymous_Object (Etype (P_Name))) 7856 then 7857 Find_Expanded_Name (N); 7858 7859 else 7860 Analyze_Selected_Component (N); 7861 return; 7862 end if; 7863 7864 else 7865 Find_Expanded_Name (N); 7866 end if; 7867 7868 elsif Ekind (P_Name) = E_Package then 7869 Find_Expanded_Name (N); 7870 7871 elsif Is_Overloadable (P_Name) then 7872 7873 -- The subprogram may be a renaming (of an enclosing scope) as 7874 -- in the case of the name of the generic within an instantiation. 7875 7876 if Ekind (P_Name) in E_Procedure | E_Function 7877 and then Present (Alias (P_Name)) 7878 and then Is_Generic_Instance (Alias (P_Name)) 7879 then 7880 P_Name := Alias (P_Name); 7881 end if; 7882 7883 if Is_Overloaded (P) then 7884 7885 -- The prefix must resolve to a unique enclosing construct 7886 7887 declare 7888 Found : Boolean := False; 7889 Ind : Interp_Index; 7890 It : Interp; 7891 7892 begin 7893 Get_First_Interp (P, Ind, It); 7894 while Present (It.Nam) loop 7895 if In_Open_Scopes (It.Nam) then 7896 if Found then 7897 Error_Msg_N ( 7898 "prefix must be unique enclosing scope", N); 7899 Set_Entity (N, Any_Id); 7900 Set_Etype (N, Any_Type); 7901 return; 7902 7903 else 7904 Found := True; 7905 P_Name := It.Nam; 7906 end if; 7907 end if; 7908 7909 Get_Next_Interp (Ind, It); 7910 end loop; 7911 end; 7912 end if; 7913 7914 if In_Open_Scopes (P_Name) then 7915 Set_Entity (P, P_Name); 7916 Set_Is_Overloaded (P, False); 7917 Find_Expanded_Name (N); 7918 7919 else 7920 -- If no interpretation as an expanded name is possible, it 7921 -- must be a selected component of a record returned by a 7922 -- function call. Reformat prefix as a function call, the rest 7923 -- is done by type resolution. 7924 7925 -- Error if the prefix is procedure or entry, as is P.X 7926 7927 if Ekind (P_Name) /= E_Function 7928 and then 7929 (not Is_Overloaded (P) 7930 or else Nkind (Parent (N)) = N_Procedure_Call_Statement) 7931 then 7932 -- Prefix may mention a package that is hidden by a local 7933 -- declaration: let the user know. Scan the full homonym 7934 -- chain, the candidate package may be anywhere on it. 7935 7936 if Present (Homonym (Current_Entity (P_Name))) then 7937 P_Name := Current_Entity (P_Name); 7938 7939 while Present (P_Name) loop 7940 exit when Ekind (P_Name) = E_Package; 7941 P_Name := Homonym (P_Name); 7942 end loop; 7943 7944 if Present (P_Name) then 7945 if not Is_Reference_In_Subunit then 7946 Error_Msg_Sloc := Sloc (Entity (Prefix (N))); 7947 Error_Msg_NE 7948 ("package& is hidden by declaration#", N, P_Name); 7949 end if; 7950 7951 Set_Entity (Prefix (N), P_Name); 7952 Find_Expanded_Name (N); 7953 return; 7954 7955 else 7956 P_Name := Entity (Prefix (N)); 7957 end if; 7958 end if; 7959 7960 Error_Msg_NE 7961 ("invalid prefix in selected component&", N, P_Name); 7962 Change_Selected_Component_To_Expanded_Name (N); 7963 Set_Entity (N, Any_Id); 7964 Set_Etype (N, Any_Type); 7965 7966 -- Here we have a function call, so do the reformatting 7967 7968 else 7969 Nam := New_Copy (P); 7970 Save_Interps (P, Nam); 7971 7972 -- We use Replace here because this is one of those cases 7973 -- where the parser has missclassified the node, and we fix 7974 -- things up and then do the semantic analysis on the fixed 7975 -- up node. Normally we do this using one of the Sinfo.CN 7976 -- routines, but this is too tricky for that. 7977 7978 -- Note that using Rewrite would be wrong, because we would 7979 -- have a tree where the original node is unanalyzed. 7980 7981 Replace (P, 7982 Make_Function_Call (Sloc (P), Name => Nam)); 7983 7984 -- Now analyze the reformatted node 7985 7986 Analyze_Call (P); 7987 7988 -- If the prefix is illegal after this transformation, there 7989 -- may be visibility errors on the prefix. The safest is to 7990 -- treat the selected component as an error. 7991 7992 if Error_Posted (P) then 7993 Set_Etype (N, Any_Type); 7994 return; 7995 7996 else 7997 Analyze_Selected_Component (N); 7998 end if; 7999 end if; 8000 end if; 8001 8002 -- Remaining cases generate various error messages 8003 8004 else 8005 -- Format node as expanded name, to avoid cascaded errors 8006 8007 Change_Selected_Component_To_Expanded_Name (N); 8008 Set_Entity (N, Any_Id); 8009 Set_Etype (N, Any_Type); 8010 8011 -- Issue error message, but avoid this if error issued already. 8012 -- Use identifier of prefix if one is available. 8013 8014 if P_Name = Any_Id then 8015 null; 8016 8017 -- It is not an error if the prefix is the current instance of 8018 -- type name, e.g. the expression of a type aspect, when it is 8019 -- analyzed within a generic unit. We still have to verify that a 8020 -- component of that name exists, and decorate the node 8021 -- accordingly. 8022 8023 elsif Is_Entity_Name (P) and then Is_Current_Instance (P) then 8024 declare 8025 Comp : Entity_Id; 8026 8027 begin 8028 Comp := First_Entity (Entity (P)); 8029 while Present (Comp) loop 8030 if Chars (Comp) = Chars (Selector_Name (N)) then 8031 Set_Entity (N, Comp); 8032 Set_Etype (N, Etype (Comp)); 8033 Set_Entity (Selector_Name (N), Comp); 8034 Set_Etype (Selector_Name (N), Etype (Comp)); 8035 return; 8036 end if; 8037 8038 Next_Entity (Comp); 8039 end loop; 8040 end; 8041 8042 elsif Ekind (P_Name) = E_Void then 8043 Premature_Usage (P); 8044 8045 elsif Ekind (P_Name) = E_Generic_Package then 8046 Error_Msg_N ("prefix must not be a generic package", N); 8047 Error_Msg_N ("\use package instantiation as prefix instead", N); 8048 8049 elsif Nkind (P) /= N_Attribute_Reference then 8050 8051 -- This may have been meant as a prefixed call to a primitive 8052 -- of an untagged type. If it is a function call check type of 8053 -- its first formal and add explanation. 8054 8055 declare 8056 F : constant Entity_Id := 8057 Current_Entity (Selector_Name (N)); 8058 begin 8059 if Present (F) 8060 and then Is_Overloadable (F) 8061 and then Present (First_Entity (F)) 8062 and then not Is_Tagged_Type (Etype (First_Entity (F))) 8063 then 8064 Error_Msg_N 8065 ("prefixed call is only allowed for objects of a " 8066 & "tagged type unless -gnatX is used", N); 8067 8068 if not Extensions_Allowed 8069 and then 8070 Try_Object_Operation (N, Allow_Extensions => True) 8071 then 8072 Error_Msg_N 8073 ("\using -gnatX would make the prefixed call legal", 8074 N); 8075 end if; 8076 end if; 8077 end; 8078 8079 Error_Msg_N ("invalid prefix in selected component&", P); 8080 8081 if Is_Incomplete_Type (P_Type) 8082 and then Is_Access_Type (Etype (P)) 8083 then 8084 Error_Msg_N 8085 ("\dereference must not be of an incomplete type " 8086 & "(RM 3.10.1)", P); 8087 end if; 8088 8089 else 8090 Error_Msg_N ("invalid prefix in selected component", P); 8091 end if; 8092 end if; 8093 else 8094 -- If prefix is not the name of an entity, it must be an expression, 8095 -- whose type is appropriate for a record. This is determined by 8096 -- type resolution. 8097 8098 Analyze_Selected_Component (N); 8099 end if; 8100 8101 Analyze_Dimension (N); 8102 end Find_Selected_Component; 8103 8104 --------------- 8105 -- Find_Type -- 8106 --------------- 8107 8108 procedure Find_Type (N : Node_Id) is 8109 C : Entity_Id; 8110 Typ : Entity_Id; 8111 T : Entity_Id; 8112 T_Name : Entity_Id; 8113 8114 begin 8115 if N = Error then 8116 return; 8117 8118 elsif Nkind (N) = N_Attribute_Reference then 8119 8120 -- Class attribute. This is not valid in Ada 83 mode, but we do not 8121 -- need to enforce that at this point, since the declaration of the 8122 -- tagged type in the prefix would have been flagged already. 8123 8124 if Attribute_Name (N) = Name_Class then 8125 Check_Restriction (No_Dispatch, N); 8126 Find_Type (Prefix (N)); 8127 8128 -- Propagate error from bad prefix 8129 8130 if Etype (Prefix (N)) = Any_Type then 8131 Set_Entity (N, Any_Type); 8132 Set_Etype (N, Any_Type); 8133 return; 8134 end if; 8135 8136 T := Base_Type (Entity (Prefix (N))); 8137 8138 -- Case where type is not known to be tagged. Its appearance in 8139 -- the prefix of the 'Class attribute indicates that the full view 8140 -- will be tagged. 8141 8142 if not Is_Tagged_Type (T) then 8143 if Ekind (T) = E_Incomplete_Type then 8144 8145 -- It is legal to denote the class type of an incomplete 8146 -- type. The full type will have to be tagged, of course. 8147 -- In Ada 2005 this usage is declared obsolescent, so we 8148 -- warn accordingly. This usage is only legal if the type 8149 -- is completed in the current scope, and not for a limited 8150 -- view of a type. 8151 8152 if Ada_Version >= Ada_2005 then 8153 8154 -- Test whether the Available_View of a limited type view 8155 -- is tagged, since the limited view may not be marked as 8156 -- tagged if the type itself has an untagged incomplete 8157 -- type view in its package. 8158 8159 if From_Limited_With (T) 8160 and then not Is_Tagged_Type (Available_View (T)) 8161 then 8162 Error_Msg_N 8163 ("prefix of Class attribute must be tagged", N); 8164 Set_Etype (N, Any_Type); 8165 Set_Entity (N, Any_Type); 8166 return; 8167 8168 else 8169 if Restriction_Check_Required (No_Obsolescent_Features) 8170 then 8171 Check_Restriction 8172 (No_Obsolescent_Features, Prefix (N)); 8173 end if; 8174 8175 if Warn_On_Obsolescent_Feature then 8176 Error_Msg_N 8177 ("applying ''Class to an untagged incomplete type" 8178 & " is an obsolescent feature (RM J.11)?r?", N); 8179 end if; 8180 end if; 8181 end if; 8182 8183 Set_Is_Tagged_Type (T); 8184 Set_Direct_Primitive_Operations (T, New_Elmt_List); 8185 Make_Class_Wide_Type (T); 8186 Set_Entity (N, Class_Wide_Type (T)); 8187 Set_Etype (N, Class_Wide_Type (T)); 8188 8189 elsif Ekind (T) = E_Private_Type 8190 and then not Is_Generic_Type (T) 8191 and then In_Private_Part (Scope (T)) 8192 then 8193 -- The Class attribute can be applied to an untagged private 8194 -- type fulfilled by a tagged type prior to the full type 8195 -- declaration (but only within the parent package's private 8196 -- part). Create the class-wide type now and check that the 8197 -- full type is tagged later during its analysis. Note that 8198 -- we do not mark the private type as tagged, unlike the 8199 -- case of incomplete types, because the type must still 8200 -- appear untagged to outside units. 8201 8202 if No (Class_Wide_Type (T)) then 8203 Make_Class_Wide_Type (T); 8204 end if; 8205 8206 Set_Entity (N, Class_Wide_Type (T)); 8207 Set_Etype (N, Class_Wide_Type (T)); 8208 8209 else 8210 -- Should we introduce a type Any_Tagged and use Wrong_Type 8211 -- here, it would be a bit more consistent??? 8212 8213 Error_Msg_NE 8214 ("tagged type required, found}", 8215 Prefix (N), First_Subtype (T)); 8216 Set_Entity (N, Any_Type); 8217 return; 8218 end if; 8219 8220 -- Case of tagged type 8221 8222 else 8223 if Is_Concurrent_Type (T) then 8224 if No (Corresponding_Record_Type (Entity (Prefix (N)))) then 8225 8226 -- Previous error. Create a class-wide type for the 8227 -- synchronized type itself, with minimal semantic 8228 -- attributes, to catch other errors in some ACATS tests. 8229 8230 pragma Assert (Serious_Errors_Detected /= 0); 8231 Make_Class_Wide_Type (T); 8232 C := Class_Wide_Type (T); 8233 Set_First_Entity (C, First_Entity (T)); 8234 8235 else 8236 C := Class_Wide_Type 8237 (Corresponding_Record_Type (Entity (Prefix (N)))); 8238 end if; 8239 8240 else 8241 C := Class_Wide_Type (Entity (Prefix (N))); 8242 end if; 8243 8244 Set_Entity_With_Checks (N, C); 8245 Generate_Reference (C, N); 8246 Set_Etype (N, C); 8247 end if; 8248 8249 -- Base attribute, not allowed in Ada 83 8250 8251 elsif Attribute_Name (N) = Name_Base then 8252 if Ada_Version = Ada_83 and then Comes_From_Source (N) then 8253 Error_Msg_N 8254 ("(Ada 83) Base attribute not allowed in subtype mark", N); 8255 8256 else 8257 Find_Type (Prefix (N)); 8258 Typ := Entity (Prefix (N)); 8259 8260 if Ada_Version >= Ada_95 8261 and then not Is_Scalar_Type (Typ) 8262 and then not Is_Generic_Type (Typ) 8263 then 8264 Error_Msg_N 8265 ("prefix of Base attribute must be scalar type", 8266 Prefix (N)); 8267 8268 elsif Warn_On_Redundant_Constructs 8269 and then Base_Type (Typ) = Typ 8270 then 8271 Error_Msg_NE -- CODEFIX 8272 ("redundant attribute, & is its own base type?r?", N, Typ); 8273 end if; 8274 8275 T := Base_Type (Typ); 8276 8277 -- Rewrite attribute reference with type itself (see similar 8278 -- processing in Analyze_Attribute, case Base). Preserve prefix 8279 -- if present, for other legality checks. 8280 8281 if Nkind (Prefix (N)) = N_Expanded_Name then 8282 Rewrite (N, 8283 Make_Expanded_Name (Sloc (N), 8284 Chars => Chars (T), 8285 Prefix => New_Copy (Prefix (Prefix (N))), 8286 Selector_Name => New_Occurrence_Of (T, Sloc (N)))); 8287 8288 else 8289 Rewrite (N, New_Occurrence_Of (T, Sloc (N))); 8290 end if; 8291 8292 Set_Entity (N, T); 8293 Set_Etype (N, T); 8294 end if; 8295 8296 elsif Attribute_Name (N) = Name_Stub_Type then 8297 8298 -- This is handled in Analyze_Attribute 8299 8300 Analyze (N); 8301 8302 -- All other attributes are invalid in a subtype mark 8303 8304 else 8305 Error_Msg_N ("invalid attribute in subtype mark", N); 8306 end if; 8307 8308 else 8309 Analyze (N); 8310 8311 if Is_Entity_Name (N) then 8312 T_Name := Entity (N); 8313 else 8314 Error_Msg_N ("subtype mark required in this context", N); 8315 Set_Etype (N, Any_Type); 8316 return; 8317 end if; 8318 8319 if T_Name = Any_Id or else Etype (N) = Any_Type then 8320 8321 -- Undefined id. Make it into a valid type 8322 8323 Set_Entity (N, Any_Type); 8324 8325 elsif not Is_Type (T_Name) 8326 and then T_Name /= Standard_Void_Type 8327 then 8328 Error_Msg_Sloc := Sloc (T_Name); 8329 Error_Msg_N ("subtype mark required in this context", N); 8330 Error_Msg_NE ("\\found & declared#", N, T_Name); 8331 Set_Entity (N, Any_Type); 8332 8333 else 8334 -- If the type is an incomplete type created to handle 8335 -- anonymous access components of a record type, then the 8336 -- incomplete type is the visible entity and subsequent 8337 -- references will point to it. Mark the original full 8338 -- type as referenced, to prevent spurious warnings. 8339 8340 if Is_Incomplete_Type (T_Name) 8341 and then Present (Full_View (T_Name)) 8342 and then not Comes_From_Source (T_Name) 8343 then 8344 Set_Referenced (Full_View (T_Name)); 8345 end if; 8346 8347 T_Name := Get_Full_View (T_Name); 8348 8349 -- Ada 2005 (AI-251, AI-50217): Handle interfaces visible through 8350 -- limited-with clauses 8351 8352 if From_Limited_With (T_Name) 8353 and then Is_Incomplete_Type (T_Name) 8354 and then Present (Non_Limited_View (T_Name)) 8355 and then Is_Interface (Non_Limited_View (T_Name)) 8356 then 8357 T_Name := Non_Limited_View (T_Name); 8358 end if; 8359 8360 if In_Open_Scopes (T_Name) then 8361 if Ekind (Base_Type (T_Name)) = E_Task_Type then 8362 8363 -- In Ada 2005, a task name can be used in an access 8364 -- definition within its own body. 8365 8366 if Ada_Version >= Ada_2005 8367 and then Nkind (Parent (N)) = N_Access_Definition 8368 then 8369 Set_Entity (N, T_Name); 8370 Set_Etype (N, T_Name); 8371 return; 8372 8373 else 8374 Error_Msg_N 8375 ("task type cannot be used as type mark " & 8376 "within its own spec or body", N); 8377 end if; 8378 8379 elsif Ekind (Base_Type (T_Name)) = E_Protected_Type then 8380 8381 -- In Ada 2005, a protected name can be used in an access 8382 -- definition within its own body. 8383 8384 if Ada_Version >= Ada_2005 8385 and then Nkind (Parent (N)) = N_Access_Definition 8386 then 8387 Set_Entity (N, T_Name); 8388 Set_Etype (N, T_Name); 8389 return; 8390 8391 else 8392 Error_Msg_N 8393 ("protected type cannot be used as type mark " & 8394 "within its own spec or body", N); 8395 end if; 8396 8397 else 8398 Error_Msg_N ("type declaration cannot refer to itself", N); 8399 end if; 8400 8401 Set_Etype (N, Any_Type); 8402 Set_Entity (N, Any_Type); 8403 Set_Error_Posted (T_Name); 8404 return; 8405 end if; 8406 8407 Set_Entity (N, T_Name); 8408 Set_Etype (N, T_Name); 8409 end if; 8410 end if; 8411 8412 if Present (Etype (N)) and then Comes_From_Source (N) then 8413 if Is_Fixed_Point_Type (Etype (N)) then 8414 Check_Restriction (No_Fixed_Point, N); 8415 elsif Is_Floating_Point_Type (Etype (N)) then 8416 Check_Restriction (No_Floating_Point, N); 8417 end if; 8418 8419 -- A Ghost type must appear in a specific context 8420 8421 if Is_Ghost_Entity (Etype (N)) then 8422 Check_Ghost_Context (Etype (N), N); 8423 end if; 8424 end if; 8425 end Find_Type; 8426 8427 -------------------- 8428 -- Has_Components -- 8429 -------------------- 8430 8431 function Has_Components (Typ : Entity_Id) return Boolean is 8432 begin 8433 return Is_Record_Type (Typ) 8434 or else (Is_Private_Type (Typ) and then Has_Discriminants (Typ)) 8435 or else (Is_Task_Type (Typ) and then Has_Discriminants (Typ)) 8436 or else (Is_Incomplete_Type (Typ) 8437 and then From_Limited_With (Typ) 8438 and then Is_Record_Type (Available_View (Typ))); 8439 end Has_Components; 8440 8441 ------------------------------------ 8442 -- Has_Implicit_Character_Literal -- 8443 ------------------------------------ 8444 8445 function Has_Implicit_Character_Literal (N : Node_Id) return Boolean is 8446 Id : Entity_Id; 8447 Found : Boolean := False; 8448 P : constant Entity_Id := Entity (Prefix (N)); 8449 Priv_Id : Entity_Id := Empty; 8450 8451 begin 8452 if Ekind (P) = E_Package and then not In_Open_Scopes (P) then 8453 Priv_Id := First_Private_Entity (P); 8454 end if; 8455 8456 if P = Standard_Standard then 8457 Change_Selected_Component_To_Expanded_Name (N); 8458 Rewrite (N, Selector_Name (N)); 8459 Analyze (N); 8460 Set_Etype (Original_Node (N), Standard_Character); 8461 return True; 8462 end if; 8463 8464 Id := First_Entity (P); 8465 while Present (Id) and then Id /= Priv_Id loop 8466 if Is_Standard_Character_Type (Id) and then Is_Base_Type (Id) then 8467 8468 -- We replace the node with the literal itself, resolve as a 8469 -- character, and set the type correctly. 8470 8471 if not Found then 8472 Change_Selected_Component_To_Expanded_Name (N); 8473 Rewrite (N, Selector_Name (N)); 8474 Analyze (N); 8475 Set_Etype (N, Id); 8476 Set_Etype (Original_Node (N), Id); 8477 Found := True; 8478 8479 else 8480 -- More than one type derived from Character in given scope. 8481 -- Collect all possible interpretations. 8482 8483 Add_One_Interp (N, Id, Id); 8484 end if; 8485 end if; 8486 8487 Next_Entity (Id); 8488 end loop; 8489 8490 return Found; 8491 end Has_Implicit_Character_Literal; 8492 8493 ---------------------- 8494 -- Has_Private_With -- 8495 ---------------------- 8496 8497 function Has_Private_With (E : Entity_Id) return Boolean is 8498 Comp_Unit : constant Node_Id := Cunit (Current_Sem_Unit); 8499 Item : Node_Id; 8500 8501 begin 8502 Item := First (Context_Items (Comp_Unit)); 8503 while Present (Item) loop 8504 if Nkind (Item) = N_With_Clause 8505 and then Private_Present (Item) 8506 and then Entity (Name (Item)) = E 8507 then 8508 return True; 8509 end if; 8510 8511 Next (Item); 8512 end loop; 8513 8514 return False; 8515 end Has_Private_With; 8516 8517 --------------------------- 8518 -- Has_Implicit_Operator -- 8519 --------------------------- 8520 8521 function Has_Implicit_Operator (N : Node_Id) return Boolean is 8522 Op_Id : constant Name_Id := Chars (Selector_Name (N)); 8523 P : constant Entity_Id := Entity (Prefix (N)); 8524 Id : Entity_Id; 8525 Priv_Id : Entity_Id := Empty; 8526 8527 procedure Add_Implicit_Operator 8528 (T : Entity_Id; 8529 Op_Type : Entity_Id := Empty); 8530 -- Add implicit interpretation to node N, using the type for which a 8531 -- predefined operator exists. If the operator yields a boolean type, 8532 -- the Operand_Type is implicitly referenced by the operator, and a 8533 -- reference to it must be generated. 8534 8535 --------------------------- 8536 -- Add_Implicit_Operator -- 8537 --------------------------- 8538 8539 procedure Add_Implicit_Operator 8540 (T : Entity_Id; 8541 Op_Type : Entity_Id := Empty) 8542 is 8543 Predef_Op : Entity_Id; 8544 8545 begin 8546 Predef_Op := Current_Entity (Selector_Name (N)); 8547 while Present (Predef_Op) 8548 and then Scope (Predef_Op) /= Standard_Standard 8549 loop 8550 Predef_Op := Homonym (Predef_Op); 8551 end loop; 8552 8553 if Nkind (N) = N_Selected_Component then 8554 Change_Selected_Component_To_Expanded_Name (N); 8555 end if; 8556 8557 -- If the context is an unanalyzed function call, determine whether 8558 -- a binary or unary interpretation is required. 8559 8560 if Nkind (Parent (N)) = N_Indexed_Component then 8561 declare 8562 Is_Binary_Call : constant Boolean := 8563 Present 8564 (Next (First (Expressions (Parent (N))))); 8565 Is_Binary_Op : constant Boolean := 8566 First_Entity 8567 (Predef_Op) /= Last_Entity (Predef_Op); 8568 Predef_Op2 : constant Entity_Id := Homonym (Predef_Op); 8569 8570 begin 8571 if Is_Binary_Call then 8572 if Is_Binary_Op then 8573 Add_One_Interp (N, Predef_Op, T); 8574 else 8575 Add_One_Interp (N, Predef_Op2, T); 8576 end if; 8577 else 8578 if not Is_Binary_Op then 8579 Add_One_Interp (N, Predef_Op, T); 8580 8581 -- Predef_Op2 may be empty in case of previous errors 8582 8583 elsif Present (Predef_Op2) then 8584 Add_One_Interp (N, Predef_Op2, T); 8585 end if; 8586 end if; 8587 end; 8588 8589 else 8590 Add_One_Interp (N, Predef_Op, T); 8591 8592 -- For operators with unary and binary interpretations, if 8593 -- context is not a call, add both 8594 8595 if Present (Homonym (Predef_Op)) then 8596 Add_One_Interp (N, Homonym (Predef_Op), T); 8597 end if; 8598 end if; 8599 8600 -- The node is a reference to a predefined operator, and 8601 -- an implicit reference to the type of its operands. 8602 8603 if Present (Op_Type) then 8604 Generate_Operator_Reference (N, Op_Type); 8605 else 8606 Generate_Operator_Reference (N, T); 8607 end if; 8608 end Add_Implicit_Operator; 8609 8610 -- Start of processing for Has_Implicit_Operator 8611 8612 begin 8613 if Ekind (P) = E_Package and then not In_Open_Scopes (P) then 8614 Priv_Id := First_Private_Entity (P); 8615 end if; 8616 8617 Id := First_Entity (P); 8618 8619 case Op_Id is 8620 8621 -- Boolean operators: an implicit declaration exists if the scope 8622 -- contains a declaration for a derived Boolean type, or for an 8623 -- array of Boolean type. 8624 8625 when Name_Op_And 8626 | Name_Op_Not 8627 | Name_Op_Or 8628 | Name_Op_Xor 8629 => 8630 while Id /= Priv_Id loop 8631 if Valid_Boolean_Arg (Id) and then Is_Base_Type (Id) then 8632 Add_Implicit_Operator (Id); 8633 return True; 8634 end if; 8635 8636 Next_Entity (Id); 8637 end loop; 8638 8639 -- Equality: look for any non-limited type (result is Boolean) 8640 8641 when Name_Op_Eq 8642 | Name_Op_Ne 8643 => 8644 while Id /= Priv_Id loop 8645 if Is_Type (Id) 8646 and then not Is_Limited_Type (Id) 8647 and then Is_Base_Type (Id) 8648 then 8649 Add_Implicit_Operator (Standard_Boolean, Id); 8650 return True; 8651 end if; 8652 8653 Next_Entity (Id); 8654 end loop; 8655 8656 -- Comparison operators: scalar type, or array of scalar 8657 8658 when Name_Op_Ge 8659 | Name_Op_Gt 8660 | Name_Op_Le 8661 | Name_Op_Lt 8662 => 8663 while Id /= Priv_Id loop 8664 if (Is_Scalar_Type (Id) 8665 or else (Is_Array_Type (Id) 8666 and then Is_Scalar_Type (Component_Type (Id)))) 8667 and then Is_Base_Type (Id) 8668 then 8669 Add_Implicit_Operator (Standard_Boolean, Id); 8670 return True; 8671 end if; 8672 8673 Next_Entity (Id); 8674 end loop; 8675 8676 -- Arithmetic operators: any numeric type 8677 8678 when Name_Op_Abs 8679 | Name_Op_Add 8680 | Name_Op_Divide 8681 | Name_Op_Expon 8682 | Name_Op_Mod 8683 | Name_Op_Multiply 8684 | Name_Op_Rem 8685 | Name_Op_Subtract 8686 => 8687 while Id /= Priv_Id loop 8688 if Is_Numeric_Type (Id) and then Is_Base_Type (Id) then 8689 Add_Implicit_Operator (Id); 8690 return True; 8691 end if; 8692 8693 Next_Entity (Id); 8694 end loop; 8695 8696 -- Concatenation: any one-dimensional array type 8697 8698 when Name_Op_Concat => 8699 while Id /= Priv_Id loop 8700 if Is_Array_Type (Id) 8701 and then Number_Dimensions (Id) = 1 8702 and then Is_Base_Type (Id) 8703 then 8704 Add_Implicit_Operator (Id); 8705 return True; 8706 end if; 8707 8708 Next_Entity (Id); 8709 end loop; 8710 8711 -- What is the others condition here? Should we be using a 8712 -- subtype of Name_Id that would restrict to operators ??? 8713 8714 when others => 8715 null; 8716 end case; 8717 8718 -- If we fall through, then we do not have an implicit operator 8719 8720 return False; 8721 end Has_Implicit_Operator; 8722 8723 ----------------------------------- 8724 -- Has_Loop_In_Inner_Open_Scopes -- 8725 ----------------------------------- 8726 8727 function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean is 8728 begin 8729 -- Several scope stacks are maintained by Scope_Stack. The base of the 8730 -- currently active scope stack is denoted by the Is_Active_Stack_Base 8731 -- flag in the scope stack entry. Note that the scope stacks used to 8732 -- simply be delimited implicitly by the presence of Standard_Standard 8733 -- at their base, but there now are cases where this is not sufficient 8734 -- because Standard_Standard actually may appear in the middle of the 8735 -- active set of scopes. 8736 8737 for J in reverse 0 .. Scope_Stack.Last loop 8738 8739 -- S was reached without seing a loop scope first 8740 8741 if Scope_Stack.Table (J).Entity = S then 8742 return False; 8743 8744 -- S was not yet reached, so it contains at least one inner loop 8745 8746 elsif Ekind (Scope_Stack.Table (J).Entity) = E_Loop then 8747 return True; 8748 end if; 8749 8750 -- Check Is_Active_Stack_Base to tell us when to stop, as there are 8751 -- cases where Standard_Standard appears in the middle of the active 8752 -- set of scopes. This affects the declaration and overriding of 8753 -- private inherited operations in instantiations of generic child 8754 -- units. 8755 8756 pragma Assert (not Scope_Stack.Table (J).Is_Active_Stack_Base); 8757 end loop; 8758 8759 raise Program_Error; -- unreachable 8760 end Has_Loop_In_Inner_Open_Scopes; 8761 8762 -------------------- 8763 -- In_Open_Scopes -- 8764 -------------------- 8765 8766 function In_Open_Scopes (S : Entity_Id) return Boolean is 8767 begin 8768 -- Several scope stacks are maintained by Scope_Stack. The base of the 8769 -- currently active scope stack is denoted by the Is_Active_Stack_Base 8770 -- flag in the scope stack entry. Note that the scope stacks used to 8771 -- simply be delimited implicitly by the presence of Standard_Standard 8772 -- at their base, but there now are cases where this is not sufficient 8773 -- because Standard_Standard actually may appear in the middle of the 8774 -- active set of scopes. 8775 8776 for J in reverse 0 .. Scope_Stack.Last loop 8777 if Scope_Stack.Table (J).Entity = S then 8778 return True; 8779 end if; 8780 8781 -- Check Is_Active_Stack_Base to tell us when to stop, as there are 8782 -- cases where Standard_Standard appears in the middle of the active 8783 -- set of scopes. This affects the declaration and overriding of 8784 -- private inherited operations in instantiations of generic child 8785 -- units. 8786 8787 exit when Scope_Stack.Table (J).Is_Active_Stack_Base; 8788 end loop; 8789 8790 return False; 8791 end In_Open_Scopes; 8792 8793 ----------------------------- 8794 -- Inherit_Renamed_Profile -- 8795 ----------------------------- 8796 8797 procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id) is 8798 New_F : Entity_Id; 8799 Old_F : Entity_Id; 8800 Old_T : Entity_Id; 8801 New_T : Entity_Id; 8802 8803 begin 8804 if Ekind (Old_S) = E_Operator then 8805 New_F := First_Formal (New_S); 8806 8807 while Present (New_F) loop 8808 Set_Etype (New_F, Base_Type (Etype (New_F))); 8809 Next_Formal (New_F); 8810 end loop; 8811 8812 Set_Etype (New_S, Base_Type (Etype (New_S))); 8813 8814 else 8815 New_F := First_Formal (New_S); 8816 Old_F := First_Formal (Old_S); 8817 8818 while Present (New_F) loop 8819 New_T := Etype (New_F); 8820 Old_T := Etype (Old_F); 8821 8822 -- If the new type is a renaming of the old one, as is the case 8823 -- for actuals in instances, retain its name, to simplify later 8824 -- disambiguation. 8825 8826 if Nkind (Parent (New_T)) = N_Subtype_Declaration 8827 and then Is_Entity_Name (Subtype_Indication (Parent (New_T))) 8828 and then Entity (Subtype_Indication (Parent (New_T))) = Old_T 8829 then 8830 null; 8831 else 8832 Set_Etype (New_F, Old_T); 8833 end if; 8834 8835 Next_Formal (New_F); 8836 Next_Formal (Old_F); 8837 end loop; 8838 8839 pragma Assert (No (Old_F)); 8840 8841 if Ekind (Old_S) in E_Function | E_Enumeration_Literal then 8842 Set_Etype (New_S, Etype (Old_S)); 8843 end if; 8844 end if; 8845 end Inherit_Renamed_Profile; 8846 8847 ---------------- 8848 -- Initialize -- 8849 ---------------- 8850 8851 procedure Initialize is 8852 begin 8853 Urefs.Init; 8854 end Initialize; 8855 8856 ------------------------- 8857 -- Install_Use_Clauses -- 8858 ------------------------- 8859 8860 procedure Install_Use_Clauses 8861 (Clause : Node_Id; 8862 Force_Installation : Boolean := False) 8863 is 8864 U : Node_Id; 8865 8866 begin 8867 U := Clause; 8868 while Present (U) loop 8869 8870 -- Case of USE package 8871 8872 if Nkind (U) = N_Use_Package_Clause then 8873 Use_One_Package (U, Name (U), True); 8874 8875 -- Case of USE TYPE 8876 8877 else 8878 Use_One_Type (Subtype_Mark (U), Force => Force_Installation); 8879 8880 end if; 8881 8882 Next_Use_Clause (U); 8883 end loop; 8884 end Install_Use_Clauses; 8885 8886 ---------------------- 8887 -- Mark_Use_Clauses -- 8888 ---------------------- 8889 8890 procedure Mark_Use_Clauses (Id : Node_Or_Entity_Id) is 8891 procedure Mark_Parameters (Call : Entity_Id); 8892 -- Perform use_type_clause marking for all parameters in a subprogram 8893 -- or operator call. 8894 8895 procedure Mark_Use_Package (Pak : Entity_Id); 8896 -- Move up the Prev_Use_Clause chain for packages denoted by Pak - 8897 -- marking each clause in the chain as effective in the process. 8898 8899 procedure Mark_Use_Type (E : Entity_Id); 8900 -- Similar to Do_Use_Package_Marking except we move up the 8901 -- Prev_Use_Clause chain for the type denoted by E. 8902 8903 --------------------- 8904 -- Mark_Parameters -- 8905 --------------------- 8906 8907 procedure Mark_Parameters (Call : Entity_Id) is 8908 Curr : Node_Id; 8909 8910 begin 8911 -- Move through all of the formals 8912 8913 Curr := First_Formal (Call); 8914 while Present (Curr) loop 8915 Mark_Use_Type (Curr); 8916 8917 Next_Formal (Curr); 8918 end loop; 8919 8920 -- Handle the return type 8921 8922 Mark_Use_Type (Call); 8923 end Mark_Parameters; 8924 8925 ---------------------- 8926 -- Mark_Use_Package -- 8927 ---------------------- 8928 8929 procedure Mark_Use_Package (Pak : Entity_Id) is 8930 Curr : Node_Id; 8931 8932 begin 8933 -- Ignore cases where the scope of the type is not a package (e.g. 8934 -- Standard_Standard). 8935 8936 if Ekind (Pak) /= E_Package then 8937 return; 8938 end if; 8939 8940 Curr := Current_Use_Clause (Pak); 8941 while Present (Curr) 8942 and then not Is_Effective_Use_Clause (Curr) 8943 loop 8944 -- We need to mark the previous use clauses as effective, but 8945 -- each use clause may in turn render other use_package_clauses 8946 -- effective. Additionally, it is possible to have a parent 8947 -- package renamed as a child of itself so we must check the 8948 -- prefix entity is not the same as the package we are marking. 8949 8950 if Nkind (Name (Curr)) /= N_Identifier 8951 and then Present (Prefix (Name (Curr))) 8952 and then Entity (Prefix (Name (Curr))) /= Pak 8953 then 8954 Mark_Use_Package (Entity (Prefix (Name (Curr)))); 8955 8956 -- It is also possible to have a child package without a prefix 8957 -- that relies on a previous use_package_clause. 8958 8959 elsif Nkind (Name (Curr)) = N_Identifier 8960 and then Is_Child_Unit (Entity (Name (Curr))) 8961 then 8962 Mark_Use_Package (Scope (Entity (Name (Curr)))); 8963 end if; 8964 8965 -- Mark the use_package_clause as effective and move up the chain 8966 8967 Set_Is_Effective_Use_Clause (Curr); 8968 8969 Curr := Prev_Use_Clause (Curr); 8970 end loop; 8971 end Mark_Use_Package; 8972 8973 ------------------- 8974 -- Mark_Use_Type -- 8975 ------------------- 8976 8977 procedure Mark_Use_Type (E : Entity_Id) is 8978 Curr : Node_Id; 8979 Base : Entity_Id; 8980 8981 begin 8982 -- Ignore void types and unresolved string literals and primitives 8983 8984 if Nkind (E) = N_String_Literal 8985 or else Nkind (Etype (E)) not in N_Entity 8986 or else not Is_Type (Etype (E)) 8987 then 8988 return; 8989 end if; 8990 8991 -- Primitives with class-wide operands might additionally render 8992 -- their base type's use_clauses effective - so do a recursive check 8993 -- here. 8994 8995 Base := Base_Type (Etype (E)); 8996 8997 if Ekind (Base) = E_Class_Wide_Type then 8998 Mark_Use_Type (Base); 8999 end if; 9000 9001 -- The package containing the type or operator function being used 9002 -- may be in use as well, so mark any use_package_clauses for it as 9003 -- effective. There are also additional sanity checks performed here 9004 -- for ignoring previous errors. 9005 9006 Mark_Use_Package (Scope (Base)); 9007 9008 if Nkind (E) in N_Op 9009 and then Present (Entity (E)) 9010 and then Present (Scope (Entity (E))) 9011 then 9012 Mark_Use_Package (Scope (Entity (E))); 9013 end if; 9014 9015 Curr := Current_Use_Clause (Base); 9016 while Present (Curr) 9017 and then not Is_Effective_Use_Clause (Curr) 9018 loop 9019 -- Current use_type_clause may render other use_package_clauses 9020 -- effective. 9021 9022 if Nkind (Subtype_Mark (Curr)) /= N_Identifier 9023 and then Present (Prefix (Subtype_Mark (Curr))) 9024 then 9025 Mark_Use_Package (Entity (Prefix (Subtype_Mark (Curr)))); 9026 end if; 9027 9028 -- Mark the use_type_clause as effective and move up the chain 9029 9030 Set_Is_Effective_Use_Clause (Curr); 9031 9032 Curr := Prev_Use_Clause (Curr); 9033 end loop; 9034 end Mark_Use_Type; 9035 9036 -- Start of processing for Mark_Use_Clauses 9037 9038 begin 9039 -- Use clauses in and of themselves do not count as a "use" of a 9040 -- package. 9041 9042 if Nkind (Parent (Id)) in N_Use_Package_Clause | N_Use_Type_Clause then 9043 return; 9044 end if; 9045 9046 -- Handle entities 9047 9048 if Nkind (Id) in N_Entity then 9049 9050 -- Mark the entity's package 9051 9052 if Is_Potentially_Use_Visible (Id) then 9053 Mark_Use_Package (Scope (Id)); 9054 end if; 9055 9056 -- Mark enumeration literals 9057 9058 if Ekind (Id) = E_Enumeration_Literal then 9059 Mark_Use_Type (Id); 9060 9061 -- Mark primitives 9062 9063 elsif (Is_Overloadable (Id) 9064 or else Is_Generic_Subprogram (Id)) 9065 and then (Is_Potentially_Use_Visible (Id) 9066 or else Is_Intrinsic_Subprogram (Id) 9067 or else (Ekind (Id) in E_Function | E_Procedure 9068 and then Is_Generic_Actual_Subprogram (Id))) 9069 then 9070 Mark_Parameters (Id); 9071 end if; 9072 9073 -- Handle nodes 9074 9075 else 9076 -- Mark operators 9077 9078 if Nkind (Id) in N_Op then 9079 9080 -- At this point the left operand may not be resolved if we are 9081 -- encountering multiple operators next to eachother in an 9082 -- expression. 9083 9084 if Nkind (Id) in N_Binary_Op 9085 and then not (Nkind (Left_Opnd (Id)) in N_Op) 9086 then 9087 Mark_Use_Type (Left_Opnd (Id)); 9088 end if; 9089 9090 Mark_Use_Type (Right_Opnd (Id)); 9091 Mark_Use_Type (Id); 9092 9093 -- Mark entity identifiers 9094 9095 elsif Nkind (Id) in N_Has_Entity 9096 and then (Is_Potentially_Use_Visible (Entity (Id)) 9097 or else (Is_Generic_Instance (Entity (Id)) 9098 and then Is_Immediately_Visible (Entity (Id)))) 9099 then 9100 -- Ignore fully qualified names as they do not count as a "use" of 9101 -- a package. 9102 9103 if Nkind (Id) in N_Identifier | N_Operator_Symbol 9104 or else (Present (Prefix (Id)) 9105 and then Scope (Entity (Id)) /= Entity (Prefix (Id))) 9106 then 9107 Mark_Use_Clauses (Entity (Id)); 9108 end if; 9109 end if; 9110 end if; 9111 end Mark_Use_Clauses; 9112 9113 -------------------------------- 9114 -- Most_Descendant_Use_Clause -- 9115 -------------------------------- 9116 9117 function Most_Descendant_Use_Clause 9118 (Clause1 : Entity_Id; 9119 Clause2 : Entity_Id) return Entity_Id 9120 is 9121 Scope1 : Entity_Id; 9122 Scope2 : Entity_Id; 9123 9124 begin 9125 if Clause1 = Clause2 then 9126 return Clause1; 9127 end if; 9128 9129 -- We determine which one is the most descendant by the scope distance 9130 -- to the ultimate parent unit. 9131 9132 Scope1 := Entity_Of_Unit (Unit (Parent (Clause1))); 9133 Scope2 := Entity_Of_Unit (Unit (Parent (Clause2))); 9134 while Scope1 /= Standard_Standard 9135 and then Scope2 /= Standard_Standard 9136 loop 9137 Scope1 := Scope (Scope1); 9138 Scope2 := Scope (Scope2); 9139 9140 if not Present (Scope1) then 9141 return Clause1; 9142 elsif not Present (Scope2) then 9143 return Clause2; 9144 end if; 9145 end loop; 9146 9147 if Scope1 = Standard_Standard then 9148 return Clause1; 9149 end if; 9150 9151 return Clause2; 9152 end Most_Descendant_Use_Clause; 9153 9154 --------------- 9155 -- Pop_Scope -- 9156 --------------- 9157 9158 procedure Pop_Scope is 9159 SST : Scope_Stack_Entry renames Scope_Stack.Table (Scope_Stack.Last); 9160 S : constant Entity_Id := SST.Entity; 9161 9162 begin 9163 if Debug_Flag_E then 9164 Write_Info; 9165 end if; 9166 9167 -- Set Default_Storage_Pool field of the library unit if necessary 9168 9169 if Is_Package_Or_Generic_Package (S) 9170 and then 9171 Nkind (Parent (Unit_Declaration_Node (S))) = N_Compilation_Unit 9172 then 9173 declare 9174 Aux : constant Node_Id := 9175 Aux_Decls_Node (Parent (Unit_Declaration_Node (S))); 9176 begin 9177 if No (Default_Storage_Pool (Aux)) then 9178 Set_Default_Storage_Pool (Aux, Default_Pool); 9179 end if; 9180 end; 9181 end if; 9182 9183 Scope_Suppress := SST.Save_Scope_Suppress; 9184 Local_Suppress_Stack_Top := SST.Save_Local_Suppress_Stack_Top; 9185 Check_Policy_List := SST.Save_Check_Policy_List; 9186 Default_Pool := SST.Save_Default_Storage_Pool; 9187 No_Tagged_Streams := SST.Save_No_Tagged_Streams; 9188 SPARK_Mode := SST.Save_SPARK_Mode; 9189 SPARK_Mode_Pragma := SST.Save_SPARK_Mode_Pragma; 9190 Default_SSO := SST.Save_Default_SSO; 9191 Uneval_Old := SST.Save_Uneval_Old; 9192 9193 if Debug_Flag_W then 9194 Write_Str ("<-- exiting scope: "); 9195 Write_Name (Chars (Current_Scope)); 9196 Write_Str (", Depth="); 9197 Write_Int (Int (Scope_Stack.Last)); 9198 Write_Eol; 9199 end if; 9200 9201 End_Use_Clauses (SST.First_Use_Clause); 9202 9203 -- If the actions to be wrapped are still there they will get lost 9204 -- causing incomplete code to be generated. It is better to abort in 9205 -- this case (and we do the abort even with assertions off since the 9206 -- penalty is incorrect code generation). 9207 9208 if SST.Actions_To_Be_Wrapped /= Scope_Actions'(others => No_List) then 9209 raise Program_Error; 9210 end if; 9211 9212 -- Free last subprogram name if allocated, and pop scope 9213 9214 Free (SST.Last_Subprogram_Name); 9215 Scope_Stack.Decrement_Last; 9216 end Pop_Scope; 9217 9218 ---------------- 9219 -- Push_Scope -- 9220 ---------------- 9221 9222 procedure Push_Scope (S : Entity_Id) is 9223 E : constant Entity_Id := Scope (S); 9224 9225 function Component_Alignment_Default return Component_Alignment_Kind; 9226 -- Return Component_Alignment_Kind for the newly-pushed scope. 9227 9228 function Component_Alignment_Default return Component_Alignment_Kind is 9229 begin 9230 -- Each new scope pushed onto the scope stack inherits the component 9231 -- alignment of the previous scope. This emulates the "visibility" 9232 -- semantics of pragma Component_Alignment. 9233 9234 if Scope_Stack.Last > Scope_Stack.First then 9235 return Scope_Stack.Table 9236 (Scope_Stack.Last - 1).Component_Alignment_Default; 9237 9238 -- Otherwise, this is the first scope being pushed on the scope 9239 -- stack. Inherit the component alignment from the configuration 9240 -- form of pragma Component_Alignment (if any). 9241 9242 else 9243 return Configuration_Component_Alignment; 9244 end if; 9245 end Component_Alignment_Default; 9246 9247 begin 9248 if Ekind (S) = E_Void then 9249 null; 9250 9251 -- Set scope depth if not a nonconcurrent type, and we have not yet set 9252 -- the scope depth. This means that we have the first occurrence of the 9253 -- scope, and this is where the depth is set. 9254 9255 elsif (not Is_Type (S) or else Is_Concurrent_Type (S)) 9256 and then not Scope_Depth_Set (S) 9257 then 9258 if S = Standard_Standard then 9259 Set_Scope_Depth_Value (S, Uint_0); 9260 9261 elsif Is_Child_Unit (S) then 9262 Set_Scope_Depth_Value (S, Uint_1); 9263 9264 elsif not Is_Record_Type (Current_Scope) then 9265 if Scope_Depth_Set (Current_Scope) then 9266 if Ekind (S) = E_Loop then 9267 Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope)); 9268 else 9269 Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope) + 1); 9270 end if; 9271 end if; 9272 end if; 9273 end if; 9274 9275 Scope_Stack.Increment_Last; 9276 9277 Scope_Stack.Table (Scope_Stack.Last) := 9278 (Entity => S, 9279 Save_Scope_Suppress => Scope_Suppress, 9280 Save_Local_Suppress_Stack_Top => Local_Suppress_Stack_Top, 9281 Save_Check_Policy_List => Check_Policy_List, 9282 Save_Default_Storage_Pool => Default_Pool, 9283 Save_No_Tagged_Streams => No_Tagged_Streams, 9284 Save_SPARK_Mode => SPARK_Mode, 9285 Save_SPARK_Mode_Pragma => SPARK_Mode_Pragma, 9286 Save_Default_SSO => Default_SSO, 9287 Save_Uneval_Old => Uneval_Old, 9288 Component_Alignment_Default => Component_Alignment_Default, 9289 Last_Subprogram_Name => null, 9290 Is_Transient => False, 9291 Node_To_Be_Wrapped => Empty, 9292 Pending_Freeze_Actions => No_List, 9293 Actions_To_Be_Wrapped => (others => No_List), 9294 First_Use_Clause => Empty, 9295 Is_Active_Stack_Base => False, 9296 Previous_Visibility => False, 9297 Locked_Shared_Objects => No_Elist); 9298 9299 if Debug_Flag_W then 9300 Write_Str ("--> new scope: "); 9301 Write_Name (Chars (Current_Scope)); 9302 Write_Str (", Id="); 9303 Write_Int (Int (Current_Scope)); 9304 Write_Str (", Depth="); 9305 Write_Int (Int (Scope_Stack.Last)); 9306 Write_Eol; 9307 end if; 9308 9309 -- Deal with copying flags from the previous scope to this one. This is 9310 -- not necessary if either scope is standard, or if the new scope is a 9311 -- child unit. 9312 9313 if S /= Standard_Standard 9314 and then Scope (S) /= Standard_Standard 9315 and then not Is_Child_Unit (S) 9316 then 9317 if Nkind (E) not in N_Entity then 9318 return; 9319 end if; 9320 9321 -- Copy categorization flags from Scope (S) to S, this is not done 9322 -- when Scope (S) is Standard_Standard since propagation is from 9323 -- library unit entity inwards. Copy other relevant attributes as 9324 -- well (Discard_Names in particular). 9325 9326 -- We only propagate inwards for library level entities, 9327 -- inner level subprograms do not inherit the categorization. 9328 9329 if Is_Library_Level_Entity (S) then 9330 Set_Is_Preelaborated (S, Is_Preelaborated (E)); 9331 Set_Is_Shared_Passive (S, Is_Shared_Passive (E)); 9332 Set_Discard_Names (S, Discard_Names (E)); 9333 Set_Suppress_Value_Tracking_On_Call 9334 (S, Suppress_Value_Tracking_On_Call (E)); 9335 Set_Categorization_From_Scope (E => S, Scop => E); 9336 end if; 9337 end if; 9338 9339 if Is_Child_Unit (S) 9340 and then Present (E) 9341 and then Is_Package_Or_Generic_Package (E) 9342 and then 9343 Nkind (Parent (Unit_Declaration_Node (E))) = N_Compilation_Unit 9344 then 9345 declare 9346 Aux : constant Node_Id := 9347 Aux_Decls_Node (Parent (Unit_Declaration_Node (E))); 9348 begin 9349 if Present (Default_Storage_Pool (Aux)) then 9350 Default_Pool := Default_Storage_Pool (Aux); 9351 end if; 9352 end; 9353 end if; 9354 end Push_Scope; 9355 9356 --------------------- 9357 -- Premature_Usage -- 9358 --------------------- 9359 9360 procedure Premature_Usage (N : Node_Id) is 9361 Kind : constant Node_Kind := Nkind (Parent (Entity (N))); 9362 E : Entity_Id := Entity (N); 9363 9364 begin 9365 -- Within an instance, the analysis of the actual for a formal object 9366 -- does not see the name of the object itself. This is significant only 9367 -- if the object is an aggregate, where its analysis does not do any 9368 -- name resolution on component associations. (see 4717-008). In such a 9369 -- case, look for the visible homonym on the chain. 9370 9371 if In_Instance and then Present (Homonym (E)) then 9372 E := Homonym (E); 9373 while Present (E) and then not In_Open_Scopes (Scope (E)) loop 9374 E := Homonym (E); 9375 end loop; 9376 9377 if Present (E) then 9378 Set_Entity (N, E); 9379 Set_Etype (N, Etype (E)); 9380 return; 9381 end if; 9382 end if; 9383 9384 case Kind is 9385 when N_Component_Declaration => 9386 Error_Msg_N 9387 ("component&! cannot be used before end of record declaration", 9388 N); 9389 9390 when N_Parameter_Specification => 9391 Error_Msg_N 9392 ("formal parameter&! cannot be used before end of specification", 9393 N); 9394 9395 when N_Discriminant_Specification => 9396 Error_Msg_N 9397 ("discriminant&! cannot be used before end of discriminant part", 9398 N); 9399 9400 when N_Procedure_Specification | N_Function_Specification => 9401 Error_Msg_N 9402 ("subprogram&! cannot be used before end of its declaration", 9403 N); 9404 9405 when N_Full_Type_Declaration | N_Subtype_Declaration => 9406 Error_Msg_N 9407 ("type& cannot be used before end of its declaration!", N); 9408 9409 when others => 9410 Error_Msg_N 9411 ("object& cannot be used before end of its declaration!", N); 9412 9413 -- If the premature reference appears as the expression in its own 9414 -- declaration, rewrite it to prevent compiler loops in subsequent 9415 -- uses of this mangled declaration in address clauses. 9416 9417 if Nkind (Parent (N)) = N_Object_Declaration then 9418 Set_Entity (N, Any_Id); 9419 end if; 9420 end case; 9421 end Premature_Usage; 9422 9423 ------------------------ 9424 -- Present_System_Aux -- 9425 ------------------------ 9426 9427 function Present_System_Aux (N : Node_Id := Empty) return Boolean is 9428 Loc : Source_Ptr; 9429 Aux_Name : Unit_Name_Type; 9430 Unum : Unit_Number_Type; 9431 Withn : Node_Id; 9432 With_Sys : Node_Id; 9433 The_Unit : Node_Id; 9434 9435 function Find_System (C_Unit : Node_Id) return Entity_Id; 9436 -- Scan context clause of compilation unit to find with_clause 9437 -- for System. 9438 9439 ----------------- 9440 -- Find_System -- 9441 ----------------- 9442 9443 function Find_System (C_Unit : Node_Id) return Entity_Id is 9444 With_Clause : Node_Id; 9445 9446 begin 9447 With_Clause := First (Context_Items (C_Unit)); 9448 while Present (With_Clause) loop 9449 if (Nkind (With_Clause) = N_With_Clause 9450 and then Chars (Name (With_Clause)) = Name_System) 9451 and then Comes_From_Source (With_Clause) 9452 then 9453 return With_Clause; 9454 end if; 9455 9456 Next (With_Clause); 9457 end loop; 9458 9459 return Empty; 9460 end Find_System; 9461 9462 -- Start of processing for Present_System_Aux 9463 9464 begin 9465 -- The child unit may have been loaded and analyzed already 9466 9467 if Present (System_Aux_Id) then 9468 return True; 9469 9470 -- If no previous pragma for System.Aux, nothing to load 9471 9472 elsif No (System_Extend_Unit) then 9473 return False; 9474 9475 -- Use the unit name given in the pragma to retrieve the unit. 9476 -- Verify that System itself appears in the context clause of the 9477 -- current compilation. If System is not present, an error will 9478 -- have been reported already. 9479 9480 else 9481 With_Sys := Find_System (Cunit (Current_Sem_Unit)); 9482 9483 The_Unit := Unit (Cunit (Current_Sem_Unit)); 9484 9485 if No (With_Sys) 9486 and then 9487 (Nkind (The_Unit) = N_Package_Body 9488 or else (Nkind (The_Unit) = N_Subprogram_Body 9489 and then not Acts_As_Spec (Cunit (Current_Sem_Unit)))) 9490 then 9491 With_Sys := Find_System (Library_Unit (Cunit (Current_Sem_Unit))); 9492 end if; 9493 9494 if No (With_Sys) and then Present (N) then 9495 9496 -- If we are compiling a subunit, we need to examine its 9497 -- context as well (Current_Sem_Unit is the parent unit); 9498 9499 The_Unit := Parent (N); 9500 while Nkind (The_Unit) /= N_Compilation_Unit loop 9501 The_Unit := Parent (The_Unit); 9502 end loop; 9503 9504 if Nkind (Unit (The_Unit)) = N_Subunit then 9505 With_Sys := Find_System (The_Unit); 9506 end if; 9507 end if; 9508 9509 if No (With_Sys) then 9510 return False; 9511 end if; 9512 9513 Loc := Sloc (With_Sys); 9514 Get_Name_String (Chars (Expression (System_Extend_Unit))); 9515 Name_Buffer (8 .. Name_Len + 7) := Name_Buffer (1 .. Name_Len); 9516 Name_Buffer (1 .. 7) := "system."; 9517 Name_Buffer (Name_Len + 8) := '%'; 9518 Name_Buffer (Name_Len + 9) := 's'; 9519 Name_Len := Name_Len + 9; 9520 Aux_Name := Name_Find; 9521 9522 Unum := 9523 Load_Unit 9524 (Load_Name => Aux_Name, 9525 Required => False, 9526 Subunit => False, 9527 Error_Node => With_Sys); 9528 9529 if Unum /= No_Unit then 9530 Semantics (Cunit (Unum)); 9531 System_Aux_Id := 9532 Defining_Entity (Specification (Unit (Cunit (Unum)))); 9533 9534 Withn := 9535 Make_With_Clause (Loc, 9536 Name => 9537 Make_Expanded_Name (Loc, 9538 Chars => Chars (System_Aux_Id), 9539 Prefix => 9540 New_Occurrence_Of (Scope (System_Aux_Id), Loc), 9541 Selector_Name => New_Occurrence_Of (System_Aux_Id, Loc))); 9542 9543 Set_Entity (Name (Withn), System_Aux_Id); 9544 9545 Set_Corresponding_Spec (Withn, System_Aux_Id); 9546 Set_First_Name (Withn); 9547 Set_Implicit_With (Withn); 9548 Set_Library_Unit (Withn, Cunit (Unum)); 9549 9550 Insert_After (With_Sys, Withn); 9551 Mark_Rewrite_Insertion (Withn); 9552 Set_Context_Installed (Withn); 9553 9554 return True; 9555 9556 -- Here if unit load failed 9557 9558 else 9559 Error_Msg_Name_1 := Name_System; 9560 Error_Msg_Name_2 := Chars (Expression (System_Extend_Unit)); 9561 Error_Msg_N 9562 ("extension package `%.%` does not exist", 9563 Opt.System_Extend_Unit); 9564 return False; 9565 end if; 9566 end if; 9567 end Present_System_Aux; 9568 9569 ------------------------- 9570 -- Restore_Scope_Stack -- 9571 ------------------------- 9572 9573 procedure Restore_Scope_Stack 9574 (List : Elist_Id; 9575 Handle_Use : Boolean := True) 9576 is 9577 SS_Last : constant Int := Scope_Stack.Last; 9578 Elmt : Elmt_Id; 9579 9580 begin 9581 -- Restore visibility of previous scope stack, if any, using the list 9582 -- we saved (we use Remove, since this list will not be used again). 9583 9584 loop 9585 Elmt := Last_Elmt (List); 9586 exit when Elmt = No_Elmt; 9587 Set_Is_Immediately_Visible (Node (Elmt)); 9588 Remove_Last_Elmt (List); 9589 end loop; 9590 9591 -- Restore use clauses 9592 9593 if SS_Last >= Scope_Stack.First 9594 and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard 9595 and then Handle_Use 9596 then 9597 Install_Use_Clauses 9598 (Scope_Stack.Table (SS_Last).First_Use_Clause, 9599 Force_Installation => True); 9600 end if; 9601 end Restore_Scope_Stack; 9602 9603 ---------------------- 9604 -- Save_Scope_Stack -- 9605 ---------------------- 9606 9607 -- Save_Scope_Stack/Restore_Scope_Stack were originally designed to avoid 9608 -- consuming any memory. That is, Save_Scope_Stack took care of removing 9609 -- from immediate visibility entities and Restore_Scope_Stack took care 9610 -- of restoring their visibility analyzing the context of each entity. The 9611 -- problem of such approach is that it was fragile and caused unexpected 9612 -- visibility problems, and indeed one test was found where there was a 9613 -- real problem. 9614 9615 -- Furthermore, the following experiment was carried out: 9616 9617 -- - Save_Scope_Stack was modified to store in an Elist1 all those 9618 -- entities whose attribute Is_Immediately_Visible is modified 9619 -- from True to False. 9620 9621 -- - Restore_Scope_Stack was modified to store in another Elist2 9622 -- all the entities whose attribute Is_Immediately_Visible is 9623 -- modified from False to True. 9624 9625 -- - Extra code was added to verify that all the elements of Elist1 9626 -- are found in Elist2 9627 9628 -- This test shows that there may be more occurrences of this problem which 9629 -- have not yet been detected. As a result, we replaced that approach by 9630 -- the current one in which Save_Scope_Stack returns the list of entities 9631 -- whose visibility is changed, and that list is passed to Restore_Scope_ 9632 -- Stack to undo that change. This approach is simpler and safer, although 9633 -- it consumes more memory. 9634 9635 function Save_Scope_Stack (Handle_Use : Boolean := True) return Elist_Id is 9636 Result : constant Elist_Id := New_Elmt_List; 9637 E : Entity_Id; 9638 S : Entity_Id; 9639 SS_Last : constant Int := Scope_Stack.Last; 9640 9641 procedure Remove_From_Visibility (E : Entity_Id); 9642 -- If E is immediately visible then append it to the result and remove 9643 -- it temporarily from visibility. 9644 9645 ---------------------------- 9646 -- Remove_From_Visibility -- 9647 ---------------------------- 9648 9649 procedure Remove_From_Visibility (E : Entity_Id) is 9650 begin 9651 if Is_Immediately_Visible (E) then 9652 Append_Elmt (E, Result); 9653 Set_Is_Immediately_Visible (E, False); 9654 end if; 9655 end Remove_From_Visibility; 9656 9657 -- Start of processing for Save_Scope_Stack 9658 9659 begin 9660 if SS_Last >= Scope_Stack.First 9661 and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard 9662 then 9663 if Handle_Use then 9664 End_Use_Clauses (Scope_Stack.Table (SS_Last).First_Use_Clause); 9665 end if; 9666 9667 -- If the call is from within a compilation unit, as when called from 9668 -- Rtsfind, make current entries in scope stack invisible while we 9669 -- analyze the new unit. 9670 9671 for J in reverse 0 .. SS_Last loop 9672 exit when Scope_Stack.Table (J).Entity = Standard_Standard 9673 or else No (Scope_Stack.Table (J).Entity); 9674 9675 S := Scope_Stack.Table (J).Entity; 9676 9677 Remove_From_Visibility (S); 9678 9679 E := First_Entity (S); 9680 while Present (E) loop 9681 Remove_From_Visibility (E); 9682 Next_Entity (E); 9683 end loop; 9684 end loop; 9685 9686 end if; 9687 9688 return Result; 9689 end Save_Scope_Stack; 9690 9691 ------------- 9692 -- Set_Use -- 9693 ------------- 9694 9695 procedure Set_Use (L : List_Id) is 9696 Decl : Node_Id; 9697 9698 begin 9699 if Present (L) then 9700 Decl := First (L); 9701 while Present (Decl) loop 9702 if Nkind (Decl) = N_Use_Package_Clause then 9703 Chain_Use_Clause (Decl); 9704 Use_One_Package (Decl, Name (Decl)); 9705 9706 elsif Nkind (Decl) = N_Use_Type_Clause then 9707 Chain_Use_Clause (Decl); 9708 Use_One_Type (Subtype_Mark (Decl)); 9709 9710 end if; 9711 9712 Next (Decl); 9713 end loop; 9714 end if; 9715 end Set_Use; 9716 9717 ----------------------------- 9718 -- Update_Use_Clause_Chain -- 9719 ----------------------------- 9720 9721 procedure Update_Use_Clause_Chain is 9722 9723 procedure Update_Chain_In_Scope (Level : Int); 9724 -- Iterate through one level in the scope stack verifying each use-type 9725 -- clause within said level is used then reset the Current_Use_Clause 9726 -- to a redundant use clause outside of the current ending scope if such 9727 -- a clause exists. 9728 9729 --------------------------- 9730 -- Update_Chain_In_Scope -- 9731 --------------------------- 9732 9733 procedure Update_Chain_In_Scope (Level : Int) is 9734 Curr : Node_Id; 9735 N : Node_Id; 9736 9737 begin 9738 -- Loop through all use clauses within the scope dictated by Level 9739 9740 Curr := Scope_Stack.Table (Level).First_Use_Clause; 9741 while Present (Curr) loop 9742 9743 -- Retrieve the subtype mark or name within the current current 9744 -- use clause. 9745 9746 if Nkind (Curr) = N_Use_Type_Clause then 9747 N := Subtype_Mark (Curr); 9748 else 9749 N := Name (Curr); 9750 end if; 9751 9752 -- If warnings for unreferenced entities are enabled and the 9753 -- current use clause has not been marked effective. 9754 9755 if Check_Unreferenced 9756 and then Comes_From_Source (Curr) 9757 and then not Is_Effective_Use_Clause (Curr) 9758 and then not In_Instance 9759 and then not In_Inlined_Body 9760 then 9761 -- We are dealing with a potentially unused use_package_clause 9762 9763 if Nkind (Curr) = N_Use_Package_Clause then 9764 9765 -- Renamings and formal subprograms may cause the associated 9766 -- node to be marked as effective instead of the original. 9767 9768 if not (Present (Associated_Node (N)) 9769 and then Present 9770 (Current_Use_Clause 9771 (Associated_Node (N))) 9772 and then Is_Effective_Use_Clause 9773 (Current_Use_Clause 9774 (Associated_Node (N)))) 9775 then 9776 Error_Msg_Node_1 := Entity (N); 9777 Error_Msg_NE 9778 ("use clause for package & has no effect?u?", 9779 Curr, Entity (N)); 9780 end if; 9781 9782 -- We are dealing with an unused use_type_clause 9783 9784 else 9785 Error_Msg_Node_1 := Etype (N); 9786 Error_Msg_NE 9787 ("use clause for } has no effect?u?", Curr, Etype (N)); 9788 end if; 9789 end if; 9790 9791 -- Verify that we haven't already processed a redundant 9792 -- use_type_clause within the same scope before we move the 9793 -- current use clause up to a previous one for type T. 9794 9795 if Present (Prev_Use_Clause (Curr)) then 9796 Set_Current_Use_Clause (Entity (N), Prev_Use_Clause (Curr)); 9797 end if; 9798 9799 Next_Use_Clause (Curr); 9800 end loop; 9801 end Update_Chain_In_Scope; 9802 9803 -- Start of processing for Update_Use_Clause_Chain 9804 9805 begin 9806 Update_Chain_In_Scope (Scope_Stack.Last); 9807 9808 -- Deal with use clauses within the context area if the current 9809 -- scope is a compilation unit. 9810 9811 if Is_Compilation_Unit (Current_Scope) 9812 and then Sloc (Scope_Stack.Table 9813 (Scope_Stack.Last - 1).Entity) = Standard_Location 9814 then 9815 Update_Chain_In_Scope (Scope_Stack.Last - 1); 9816 end if; 9817 end Update_Use_Clause_Chain; 9818 9819 --------------------- 9820 -- Use_One_Package -- 9821 --------------------- 9822 9823 procedure Use_One_Package 9824 (N : Node_Id; 9825 Pack_Name : Entity_Id := Empty; 9826 Force : Boolean := False) 9827 is 9828 procedure Note_Redundant_Use (Clause : Node_Id); 9829 -- Mark the name in a use clause as redundant if the corresponding 9830 -- entity is already use-visible. Emit a warning if the use clause comes 9831 -- from source and the proper warnings are enabled. 9832 9833 ------------------------ 9834 -- Note_Redundant_Use -- 9835 ------------------------ 9836 9837 procedure Note_Redundant_Use (Clause : Node_Id) is 9838 Decl : constant Node_Id := Parent (Clause); 9839 Pack_Name : constant Entity_Id := Entity (Clause); 9840 9841 Cur_Use : Node_Id := Current_Use_Clause (Pack_Name); 9842 Prev_Use : Node_Id := Empty; 9843 Redundant : Node_Id := Empty; 9844 -- The Use_Clause which is actually redundant. In the simplest case 9845 -- it is Pack itself, but when we compile a body we install its 9846 -- context before that of its spec, in which case it is the 9847 -- use_clause in the spec that will appear to be redundant, and we 9848 -- want the warning to be placed on the body. Similar complications 9849 -- appear when the redundancy is between a child unit and one of its 9850 -- ancestors. 9851 9852 begin 9853 -- Could be renamed... 9854 9855 if No (Cur_Use) then 9856 Cur_Use := Current_Use_Clause (Renamed_Entity (Pack_Name)); 9857 end if; 9858 9859 Set_Redundant_Use (Clause, True); 9860 9861 -- Do not check for redundant use if clause is generated, or in an 9862 -- instance, or in a predefined unit to avoid misleading warnings 9863 -- that may occur as part of a rtsfind load. 9864 9865 if not Comes_From_Source (Clause) 9866 or else In_Instance 9867 or else not Warn_On_Redundant_Constructs 9868 or else Is_Predefined_Unit (Current_Sem_Unit) 9869 then 9870 return; 9871 end if; 9872 9873 if not Is_Compilation_Unit (Current_Scope) then 9874 9875 -- If the use_clause is in an inner scope, it is made redundant by 9876 -- some clause in the current context, with one exception: If we 9877 -- are compiling a nested package body, and the use_clause comes 9878 -- from then corresponding spec, the clause is not necessarily 9879 -- fully redundant, so we should not warn. If a warning was 9880 -- warranted, it would have been given when the spec was 9881 -- processed. 9882 9883 if Nkind (Parent (Decl)) = N_Package_Specification then 9884 declare 9885 Package_Spec_Entity : constant Entity_Id := 9886 Defining_Unit_Name (Parent (Decl)); 9887 begin 9888 if In_Package_Body (Package_Spec_Entity) then 9889 return; 9890 end if; 9891 end; 9892 end if; 9893 9894 Redundant := Clause; 9895 Prev_Use := Cur_Use; 9896 9897 elsif Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Body then 9898 declare 9899 Cur_Unit : constant Unit_Number_Type := 9900 Get_Source_Unit (Cur_Use); 9901 New_Unit : constant Unit_Number_Type := 9902 Get_Source_Unit (Clause); 9903 9904 Scop : Entity_Id; 9905 9906 begin 9907 if Cur_Unit = New_Unit then 9908 9909 -- Redundant clause in same body 9910 9911 Redundant := Clause; 9912 Prev_Use := Cur_Use; 9913 9914 elsif Cur_Unit = Current_Sem_Unit then 9915 9916 -- If the new clause is not in the current unit it has been 9917 -- analyzed first, and it makes the other one redundant. 9918 -- However, if the new clause appears in a subunit, Cur_Unit 9919 -- is still the parent, and in that case the redundant one 9920 -- is the one appearing in the subunit. 9921 9922 if Nkind (Unit (Cunit (New_Unit))) = N_Subunit then 9923 Redundant := Clause; 9924 Prev_Use := Cur_Use; 9925 9926 -- Most common case: redundant clause in body, original 9927 -- clause in spec. Current scope is spec entity. 9928 9929 elsif Current_Scope = Cunit_Entity (Current_Sem_Unit) then 9930 Redundant := Cur_Use; 9931 Prev_Use := Clause; 9932 9933 else 9934 -- The new clause may appear in an unrelated unit, when 9935 -- the parents of a generic are being installed prior to 9936 -- instantiation. In this case there must be no warning. 9937 -- We detect this case by checking whether the current 9938 -- top of the stack is related to the current 9939 -- compilation. 9940 9941 Scop := Current_Scope; 9942 while Present (Scop) 9943 and then Scop /= Standard_Standard 9944 loop 9945 if Is_Compilation_Unit (Scop) 9946 and then not Is_Child_Unit (Scop) 9947 then 9948 return; 9949 9950 elsif Scop = Cunit_Entity (Current_Sem_Unit) then 9951 exit; 9952 end if; 9953 9954 Scop := Scope (Scop); 9955 end loop; 9956 9957 Redundant := Cur_Use; 9958 Prev_Use := Clause; 9959 end if; 9960 9961 elsif New_Unit = Current_Sem_Unit then 9962 Redundant := Clause; 9963 Prev_Use := Cur_Use; 9964 9965 else 9966 -- Neither is the current unit, so they appear in parent or 9967 -- sibling units. Warning will be emitted elsewhere. 9968 9969 return; 9970 end if; 9971 end; 9972 9973 elsif Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Declaration 9974 and then Present (Parent_Spec (Unit (Cunit (Current_Sem_Unit)))) 9975 then 9976 -- Use_clause is in child unit of current unit, and the child unit 9977 -- appears in the context of the body of the parent, so it has 9978 -- been installed first, even though it is the redundant one. 9979 -- Depending on their placement in the context, the visible or the 9980 -- private parts of the two units, either might appear as 9981 -- redundant, but the message has to be on the current unit. 9982 9983 if Get_Source_Unit (Cur_Use) = Current_Sem_Unit then 9984 Redundant := Cur_Use; 9985 Prev_Use := Clause; 9986 else 9987 Redundant := Clause; 9988 Prev_Use := Cur_Use; 9989 end if; 9990 9991 -- If the new use clause appears in the private part of a parent 9992 -- unit it may appear to be redundant w.r.t. a use clause in a 9993 -- child unit, but the previous use clause was needed in the 9994 -- visible part of the child, and no warning should be emitted. 9995 9996 if Nkind (Parent (Decl)) = N_Package_Specification 9997 and then List_Containing (Decl) = 9998 Private_Declarations (Parent (Decl)) 9999 then 10000 declare 10001 Par : constant Entity_Id := 10002 Defining_Entity (Parent (Decl)); 10003 Spec : constant Node_Id := 10004 Specification (Unit (Cunit (Current_Sem_Unit))); 10005 Cur_List : constant List_Id := List_Containing (Cur_Use); 10006 10007 begin 10008 if Is_Compilation_Unit (Par) 10009 and then Par /= Cunit_Entity (Current_Sem_Unit) 10010 then 10011 if Cur_List = Context_Items (Cunit (Current_Sem_Unit)) 10012 or else Cur_List = Visible_Declarations (Spec) 10013 then 10014 return; 10015 end if; 10016 end if; 10017 end; 10018 end if; 10019 10020 -- Finally, if the current use clause is in the context then the 10021 -- clause is redundant when it is nested within the unit. 10022 10023 elsif Nkind (Parent (Cur_Use)) = N_Compilation_Unit 10024 and then Nkind (Parent (Parent (Clause))) /= N_Compilation_Unit 10025 and then Get_Source_Unit (Cur_Use) = Get_Source_Unit (Clause) 10026 then 10027 Redundant := Clause; 10028 Prev_Use := Cur_Use; 10029 end if; 10030 10031 if Present (Redundant) and then Parent (Redundant) /= Prev_Use then 10032 10033 -- Make sure we are looking at most-descendant use_package_clause 10034 -- by traversing the chain with Find_First_Use and then verifying 10035 -- there is no scope manipulation via Most_Descendant_Use_Clause. 10036 10037 if Nkind (Prev_Use) = N_Use_Package_Clause 10038 and then 10039 (Nkind (Parent (Prev_Use)) /= N_Compilation_Unit 10040 or else Most_Descendant_Use_Clause 10041 (Prev_Use, Find_First_Use (Prev_Use)) /= Prev_Use) 10042 then 10043 Prev_Use := Find_First_Use (Prev_Use); 10044 end if; 10045 10046 Error_Msg_Sloc := Sloc (Prev_Use); 10047 Error_Msg_NE -- CODEFIX 10048 ("& is already use-visible through previous use_clause #?r?", 10049 Redundant, Pack_Name); 10050 end if; 10051 end Note_Redundant_Use; 10052 10053 -- Local variables 10054 10055 Current_Instance : Entity_Id := Empty; 10056 Id : Entity_Id; 10057 P : Entity_Id; 10058 Prev : Entity_Id; 10059 Private_With_OK : Boolean := False; 10060 Real_P : Entity_Id; 10061 10062 -- Start of processing for Use_One_Package 10063 10064 begin 10065 -- Use_One_Package may have been called recursively to handle an 10066 -- implicit use for a auxiliary system package, so set P accordingly 10067 -- and skip redundancy checks. 10068 10069 if No (Pack_Name) and then Present_System_Aux (N) then 10070 P := System_Aux_Id; 10071 10072 -- Check for redundant use_package_clauses 10073 10074 else 10075 -- Ignore cases where we are dealing with a non user defined package 10076 -- like Standard_Standard or something other than a valid package. 10077 10078 if not Is_Entity_Name (Pack_Name) 10079 or else No (Entity (Pack_Name)) 10080 or else Ekind (Entity (Pack_Name)) /= E_Package 10081 then 10082 return; 10083 end if; 10084 10085 -- When a renaming exists we must check it for redundancy. The 10086 -- original package would have already been seen at this point. 10087 10088 if Present (Renamed_Entity (Entity (Pack_Name))) then 10089 P := Renamed_Entity (Entity (Pack_Name)); 10090 else 10091 P := Entity (Pack_Name); 10092 end if; 10093 10094 -- Check for redundant clauses then set the current use clause for 10095 -- P if were are not "forcing" an installation from a scope 10096 -- reinstallation that is done throughout analysis for various 10097 -- reasons. 10098 10099 if In_Use (P) then 10100 Note_Redundant_Use (Pack_Name); 10101 10102 if not Force then 10103 Set_Current_Use_Clause (P, N); 10104 end if; 10105 10106 return; 10107 10108 -- Warn about detected redundant clauses 10109 10110 elsif not Force 10111 and then In_Open_Scopes (P) 10112 and then not Is_Hidden_Open_Scope (P) 10113 then 10114 if Warn_On_Redundant_Constructs and then P = Current_Scope then 10115 Error_Msg_NE -- CODEFIX 10116 ("& is already use-visible within itself?r?", 10117 Pack_Name, P); 10118 end if; 10119 10120 return; 10121 end if; 10122 10123 -- Set P back to the non-renamed package so that visiblilty of the 10124 -- entities within the package can be properly set below. 10125 10126 P := Entity (Pack_Name); 10127 end if; 10128 10129 Set_In_Use (P); 10130 Set_Current_Use_Clause (P, N); 10131 10132 -- Ada 2005 (AI-50217): Check restriction 10133 10134 if From_Limited_With (P) then 10135 Error_Msg_N ("limited withed package cannot appear in use clause", N); 10136 end if; 10137 10138 -- Find enclosing instance, if any 10139 10140 if In_Instance then 10141 Current_Instance := Current_Scope; 10142 while not Is_Generic_Instance (Current_Instance) loop 10143 Current_Instance := Scope (Current_Instance); 10144 end loop; 10145 10146 if No (Hidden_By_Use_Clause (N)) then 10147 Set_Hidden_By_Use_Clause (N, New_Elmt_List); 10148 end if; 10149 end if; 10150 10151 -- If unit is a package renaming, indicate that the renamed package is 10152 -- also in use (the flags on both entities must remain consistent, and a 10153 -- subsequent use of either of them should be recognized as redundant). 10154 10155 if Present (Renamed_Entity (P)) then 10156 Set_In_Use (Renamed_Entity (P)); 10157 Set_Current_Use_Clause (Renamed_Entity (P), N); 10158 Real_P := Renamed_Entity (P); 10159 else 10160 Real_P := P; 10161 end if; 10162 10163 -- Ada 2005 (AI-262): Check the use_clause of a private withed package 10164 -- found in the private part of a package specification 10165 10166 if In_Private_Part (Current_Scope) 10167 and then Has_Private_With (P) 10168 and then Is_Child_Unit (Current_Scope) 10169 and then Is_Child_Unit (P) 10170 and then Is_Ancestor_Package (Scope (Current_Scope), P) 10171 then 10172 Private_With_OK := True; 10173 end if; 10174 10175 -- Loop through entities in one package making them potentially 10176 -- use-visible. 10177 10178 Id := First_Entity (P); 10179 while Present (Id) 10180 and then (Id /= First_Private_Entity (P) 10181 or else Private_With_OK) -- Ada 2005 (AI-262) 10182 loop 10183 Prev := Current_Entity (Id); 10184 while Present (Prev) loop 10185 if Is_Immediately_Visible (Prev) 10186 and then (not Is_Overloadable (Prev) 10187 or else not Is_Overloadable (Id) 10188 or else (Type_Conformant (Id, Prev))) 10189 then 10190 if No (Current_Instance) then 10191 10192 -- Potentially use-visible entity remains hidden 10193 10194 goto Next_Usable_Entity; 10195 10196 -- A use clause within an instance hides outer global entities, 10197 -- which are not used to resolve local entities in the 10198 -- instance. Note that the predefined entities in Standard 10199 -- could not have been hidden in the generic by a use clause, 10200 -- and therefore remain visible. Other compilation units whose 10201 -- entities appear in Standard must be hidden in an instance. 10202 10203 -- To determine whether an entity is external to the instance 10204 -- we compare the scope depth of its scope with that of the 10205 -- current instance. However, a generic actual of a subprogram 10206 -- instance is declared in the wrapper package but will not be 10207 -- hidden by a use-visible entity. similarly, an entity that is 10208 -- declared in an enclosing instance will not be hidden by an 10209 -- an entity declared in a generic actual, which can only have 10210 -- been use-visible in the generic and will not have hidden the 10211 -- entity in the generic parent. 10212 10213 -- If Id is called Standard, the predefined package with the 10214 -- same name is in the homonym chain. It has to be ignored 10215 -- because it has no defined scope (being the only entity in 10216 -- the system with this mandated behavior). 10217 10218 elsif not Is_Hidden (Id) 10219 and then Present (Scope (Prev)) 10220 and then not Is_Wrapper_Package (Scope (Prev)) 10221 and then Scope_Depth (Scope (Prev)) < 10222 Scope_Depth (Current_Instance) 10223 and then (Scope (Prev) /= Standard_Standard 10224 or else Sloc (Prev) > Standard_Location) 10225 then 10226 if In_Open_Scopes (Scope (Prev)) 10227 and then Is_Generic_Instance (Scope (Prev)) 10228 and then Present (Associated_Formal_Package (P)) 10229 then 10230 null; 10231 10232 else 10233 Set_Is_Potentially_Use_Visible (Id); 10234 Set_Is_Immediately_Visible (Prev, False); 10235 Append_Elmt (Prev, Hidden_By_Use_Clause (N)); 10236 end if; 10237 end if; 10238 10239 -- A user-defined operator is not use-visible if the predefined 10240 -- operator for the type is immediately visible, which is the case 10241 -- if the type of the operand is in an open scope. This does not 10242 -- apply to user-defined operators that have operands of different 10243 -- types, because the predefined mixed mode operations (multiply 10244 -- and divide) apply to universal types and do not hide anything. 10245 10246 elsif Ekind (Prev) = E_Operator 10247 and then Operator_Matches_Spec (Prev, Id) 10248 and then In_Open_Scopes 10249 (Scope (Base_Type (Etype (First_Formal (Id))))) 10250 and then (No (Next_Formal (First_Formal (Id))) 10251 or else Etype (First_Formal (Id)) = 10252 Etype (Next_Formal (First_Formal (Id))) 10253 or else Chars (Prev) = Name_Op_Expon) 10254 then 10255 goto Next_Usable_Entity; 10256 10257 -- In an instance, two homonyms may become use_visible through the 10258 -- actuals of distinct formal packages. In the generic, only the 10259 -- current one would have been visible, so make the other one 10260 -- not use_visible. 10261 10262 -- In certain pathological cases it is possible that unrelated 10263 -- homonyms from distinct formal packages may exist in an 10264 -- uninstalled scope. We must test for that here. 10265 10266 elsif Present (Current_Instance) 10267 and then Is_Potentially_Use_Visible (Prev) 10268 and then not Is_Overloadable (Prev) 10269 and then Scope (Id) /= Scope (Prev) 10270 and then Used_As_Generic_Actual (Scope (Prev)) 10271 and then Used_As_Generic_Actual (Scope (Id)) 10272 and then Is_List_Member (Scope (Prev)) 10273 and then not In_Same_List (Current_Use_Clause (Scope (Prev)), 10274 Current_Use_Clause (Scope (Id))) 10275 then 10276 Set_Is_Potentially_Use_Visible (Prev, False); 10277 Append_Elmt (Prev, Hidden_By_Use_Clause (N)); 10278 end if; 10279 10280 Prev := Homonym (Prev); 10281 end loop; 10282 10283 -- On exit, we know entity is not hidden, unless it is private 10284 10285 if not Is_Hidden (Id) 10286 and then ((not Is_Child_Unit (Id)) or else Is_Visible_Lib_Unit (Id)) 10287 then 10288 Set_Is_Potentially_Use_Visible (Id); 10289 10290 if Is_Private_Type (Id) and then Present (Full_View (Id)) then 10291 Set_Is_Potentially_Use_Visible (Full_View (Id)); 10292 end if; 10293 end if; 10294 10295 <<Next_Usable_Entity>> 10296 Next_Entity (Id); 10297 end loop; 10298 10299 -- Child units are also made use-visible by a use clause, but they may 10300 -- appear after all visible declarations in the parent entity list. 10301 10302 while Present (Id) loop 10303 if Is_Child_Unit (Id) and then Is_Visible_Lib_Unit (Id) then 10304 Set_Is_Potentially_Use_Visible (Id); 10305 end if; 10306 10307 Next_Entity (Id); 10308 end loop; 10309 10310 if Chars (Real_P) = Name_System 10311 and then Scope (Real_P) = Standard_Standard 10312 and then Present_System_Aux (N) 10313 then 10314 Use_One_Package (N); 10315 end if; 10316 end Use_One_Package; 10317 10318 ------------------ 10319 -- Use_One_Type -- 10320 ------------------ 10321 10322 procedure Use_One_Type 10323 (Id : Node_Id; 10324 Installed : Boolean := False; 10325 Force : Boolean := False) 10326 is 10327 function Spec_Reloaded_For_Body return Boolean; 10328 -- Determine whether the compilation unit is a package body and the use 10329 -- type clause is in the spec of the same package. Even though the spec 10330 -- was analyzed first, its context is reloaded when analysing the body. 10331 10332 procedure Use_Class_Wide_Operations (Typ : Entity_Id); 10333 -- AI05-150: if the use_type_clause carries the "all" qualifier, 10334 -- class-wide operations of ancestor types are use-visible if the 10335 -- ancestor type is visible. 10336 10337 ---------------------------- 10338 -- Spec_Reloaded_For_Body -- 10339 ---------------------------- 10340 10341 function Spec_Reloaded_For_Body return Boolean is 10342 begin 10343 if Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Body then 10344 declare 10345 Spec : constant Node_Id := 10346 Parent (List_Containing (Parent (Id))); 10347 10348 begin 10349 -- Check whether type is declared in a package specification, 10350 -- and current unit is the corresponding package body. The 10351 -- use clauses themselves may be within a nested package. 10352 10353 return 10354 Nkind (Spec) = N_Package_Specification 10355 and then In_Same_Source_Unit 10356 (Corresponding_Body (Parent (Spec)), 10357 Cunit_Entity (Current_Sem_Unit)); 10358 end; 10359 end if; 10360 10361 return False; 10362 end Spec_Reloaded_For_Body; 10363 10364 ------------------------------- 10365 -- Use_Class_Wide_Operations -- 10366 ------------------------------- 10367 10368 procedure Use_Class_Wide_Operations (Typ : Entity_Id) is 10369 function Is_Class_Wide_Operation_Of 10370 (Op : Entity_Id; 10371 T : Entity_Id) return Boolean; 10372 -- Determine whether a subprogram has a class-wide parameter or 10373 -- result that is T'Class. 10374 10375 --------------------------------- 10376 -- Is_Class_Wide_Operation_Of -- 10377 --------------------------------- 10378 10379 function Is_Class_Wide_Operation_Of 10380 (Op : Entity_Id; 10381 T : Entity_Id) return Boolean 10382 is 10383 Formal : Entity_Id; 10384 10385 begin 10386 Formal := First_Formal (Op); 10387 while Present (Formal) loop 10388 if Etype (Formal) = Class_Wide_Type (T) then 10389 return True; 10390 end if; 10391 10392 Next_Formal (Formal); 10393 end loop; 10394 10395 if Etype (Op) = Class_Wide_Type (T) then 10396 return True; 10397 end if; 10398 10399 return False; 10400 end Is_Class_Wide_Operation_Of; 10401 10402 -- Local variables 10403 10404 Ent : Entity_Id; 10405 Scop : Entity_Id; 10406 10407 -- Start of processing for Use_Class_Wide_Operations 10408 10409 begin 10410 Scop := Scope (Typ); 10411 if not Is_Hidden (Scop) then 10412 Ent := First_Entity (Scop); 10413 while Present (Ent) loop 10414 if Is_Overloadable (Ent) 10415 and then Is_Class_Wide_Operation_Of (Ent, Typ) 10416 and then not Is_Potentially_Use_Visible (Ent) 10417 then 10418 Set_Is_Potentially_Use_Visible (Ent); 10419 Append_Elmt (Ent, Used_Operations (Parent (Id))); 10420 end if; 10421 10422 Next_Entity (Ent); 10423 end loop; 10424 end if; 10425 10426 if Is_Derived_Type (Typ) then 10427 Use_Class_Wide_Operations (Etype (Base_Type (Typ))); 10428 end if; 10429 end Use_Class_Wide_Operations; 10430 10431 -- Local variables 10432 10433 Elmt : Elmt_Id; 10434 Is_Known_Used : Boolean; 10435 Op_List : Elist_Id; 10436 T : Entity_Id; 10437 10438 -- Start of processing for Use_One_Type 10439 10440 begin 10441 if Entity (Id) = Any_Type then 10442 return; 10443 end if; 10444 10445 -- It is the type determined by the subtype mark (8.4(8)) whose 10446 -- operations become potentially use-visible. 10447 10448 T := Base_Type (Entity (Id)); 10449 10450 -- Either the type itself is used, the package where it is declared is 10451 -- in use or the entity is declared in the current package, thus 10452 -- use-visible. 10453 10454 Is_Known_Used := 10455 (In_Use (T) 10456 and then ((Present (Current_Use_Clause (T)) 10457 and then All_Present (Current_Use_Clause (T))) 10458 or else not All_Present (Parent (Id)))) 10459 or else In_Use (Scope (T)) 10460 or else Scope (T) = Current_Scope; 10461 10462 Set_Redundant_Use (Id, 10463 Is_Known_Used or else Is_Potentially_Use_Visible (T)); 10464 10465 if Ekind (T) = E_Incomplete_Type then 10466 Error_Msg_N ("premature usage of incomplete type", Id); 10467 10468 elsif In_Open_Scopes (Scope (T)) then 10469 null; 10470 10471 -- A limited view cannot appear in a use_type_clause. However, an access 10472 -- type whose designated type is limited has the flag but is not itself 10473 -- a limited view unless we only have a limited view of its enclosing 10474 -- package. 10475 10476 elsif From_Limited_With (T) and then From_Limited_With (Scope (T)) then 10477 Error_Msg_N 10478 ("incomplete type from limited view cannot appear in use clause", 10479 Id); 10480 10481 -- If the use clause is redundant, Used_Operations will usually be 10482 -- empty, but we need to set it to empty here in one case: If we are 10483 -- instantiating a generic library unit, then we install the ancestors 10484 -- of that unit in the scope stack, which involves reprocessing use 10485 -- clauses in those ancestors. Such a use clause will typically have a 10486 -- nonempty Used_Operations unless it was redundant in the generic unit, 10487 -- even if it is redundant at the place of the instantiation. 10488 10489 elsif Redundant_Use (Id) then 10490 10491 -- We must avoid incorrectly setting the Current_Use_Clause when we 10492 -- are working with a redundant clause that has already been linked 10493 -- in the Prev_Use_Clause chain, otherwise the chain will break. 10494 10495 if Present (Current_Use_Clause (T)) 10496 and then Present (Prev_Use_Clause (Current_Use_Clause (T))) 10497 and then Parent (Id) = Prev_Use_Clause (Current_Use_Clause (T)) 10498 then 10499 null; 10500 else 10501 Set_Current_Use_Clause (T, Parent (Id)); 10502 end if; 10503 10504 Set_Used_Operations (Parent (Id), New_Elmt_List); 10505 10506 -- If the subtype mark designates a subtype in a different package, 10507 -- we have to check that the parent type is visible, otherwise the 10508 -- use_type_clause is a no-op. Not clear how to do that??? 10509 10510 else 10511 Set_Current_Use_Clause (T, Parent (Id)); 10512 Set_In_Use (T); 10513 10514 -- If T is tagged, primitive operators on class-wide operands are 10515 -- also deemed available. Note that this is really necessary only 10516 -- in semantics-only mode, because the primitive operators are not 10517 -- fully constructed in this mode, but we do it in all modes for the 10518 -- sake of uniformity, as this should not matter in practice. 10519 10520 if Is_Tagged_Type (T) then 10521 Set_In_Use (Class_Wide_Type (T)); 10522 end if; 10523 10524 -- Iterate over primitive operations of the type. If an operation is 10525 -- already use_visible, it is the result of a previous use_clause, 10526 -- and already appears on the corresponding entity chain. If the 10527 -- clause is being reinstalled, operations are already use-visible. 10528 10529 if Installed then 10530 null; 10531 10532 else 10533 Op_List := Collect_Primitive_Operations (T); 10534 Elmt := First_Elmt (Op_List); 10535 while Present (Elmt) loop 10536 if (Nkind (Node (Elmt)) = N_Defining_Operator_Symbol 10537 or else Chars (Node (Elmt)) in Any_Operator_Name) 10538 and then not Is_Hidden (Node (Elmt)) 10539 and then not Is_Potentially_Use_Visible (Node (Elmt)) 10540 then 10541 Set_Is_Potentially_Use_Visible (Node (Elmt)); 10542 Append_Elmt (Node (Elmt), Used_Operations (Parent (Id))); 10543 10544 elsif Ada_Version >= Ada_2012 10545 and then All_Present (Parent (Id)) 10546 and then not Is_Hidden (Node (Elmt)) 10547 and then not Is_Potentially_Use_Visible (Node (Elmt)) 10548 then 10549 Set_Is_Potentially_Use_Visible (Node (Elmt)); 10550 Append_Elmt (Node (Elmt), Used_Operations (Parent (Id))); 10551 end if; 10552 10553 Next_Elmt (Elmt); 10554 end loop; 10555 end if; 10556 10557 if Ada_Version >= Ada_2012 10558 and then All_Present (Parent (Id)) 10559 and then Is_Tagged_Type (T) 10560 then 10561 Use_Class_Wide_Operations (T); 10562 end if; 10563 end if; 10564 10565 -- If warning on redundant constructs, check for unnecessary WITH 10566 10567 if not Force 10568 and then Warn_On_Redundant_Constructs 10569 and then Is_Known_Used 10570 10571 -- with P; with P; use P; 10572 -- package P is package X is package body X is 10573 -- type T ... use P.T; 10574 10575 -- The compilation unit is the body of X. GNAT first compiles the 10576 -- spec of X, then proceeds to the body. At that point P is marked 10577 -- as use visible. The analysis then reinstalls the spec along with 10578 -- its context. The use clause P.T is now recognized as redundant, 10579 -- but in the wrong context. Do not emit a warning in such cases. 10580 -- Do not emit a warning either if we are in an instance, there is 10581 -- no redundancy between an outer use_clause and one that appears 10582 -- within the generic. 10583 10584 and then not Spec_Reloaded_For_Body 10585 and then not In_Instance 10586 and then not In_Inlined_Body 10587 then 10588 -- The type already has a use clause 10589 10590 if In_Use (T) then 10591 10592 -- Case where we know the current use clause for the type 10593 10594 if Present (Current_Use_Clause (T)) then 10595 Use_Clause_Known : declare 10596 Clause1 : constant Node_Id := 10597 Find_First_Use (Current_Use_Clause (T)); 10598 Clause2 : constant Node_Id := Parent (Id); 10599 Ent1 : Entity_Id; 10600 Ent2 : Entity_Id; 10601 Err_No : Node_Id; 10602 Unit1 : Node_Id; 10603 Unit2 : Node_Id; 10604 10605 -- Start of processing for Use_Clause_Known 10606 10607 begin 10608 -- If both current use_type_clause and the use_type_clause 10609 -- for the type are at the compilation unit level, one of 10610 -- the units must be an ancestor of the other, and the 10611 -- warning belongs on the descendant. 10612 10613 if Nkind (Parent (Clause1)) = N_Compilation_Unit 10614 and then 10615 Nkind (Parent (Clause2)) = N_Compilation_Unit 10616 then 10617 -- If the unit is a subprogram body that acts as spec, 10618 -- the context clause is shared with the constructed 10619 -- subprogram spec. Clearly there is no redundancy. 10620 10621 if Clause1 = Clause2 then 10622 return; 10623 end if; 10624 10625 Unit1 := Unit (Parent (Clause1)); 10626 Unit2 := Unit (Parent (Clause2)); 10627 10628 -- If both clauses are on same unit, or one is the body 10629 -- of the other, or one of them is in a subunit, report 10630 -- redundancy on the later one. 10631 10632 if Unit1 = Unit2 or else Nkind (Unit1) = N_Subunit then 10633 Error_Msg_Sloc := Sloc (Current_Use_Clause (T)); 10634 Error_Msg_NE -- CODEFIX 10635 ("& is already use-visible through previous " 10636 & "use_type_clause #??", Clause1, T); 10637 return; 10638 10639 elsif Nkind (Unit2) in N_Package_Body | N_Subprogram_Body 10640 and then Nkind (Unit1) /= Nkind (Unit2) 10641 and then Nkind (Unit1) /= N_Subunit 10642 then 10643 Error_Msg_Sloc := Sloc (Clause1); 10644 Error_Msg_NE -- CODEFIX 10645 ("& is already use-visible through previous " 10646 & "use_type_clause #??", Current_Use_Clause (T), T); 10647 return; 10648 end if; 10649 10650 -- There is a redundant use_type_clause in a child unit. 10651 -- Determine which of the units is more deeply nested. 10652 -- If a unit is a package instance, retrieve the entity 10653 -- and its scope from the instance spec. 10654 10655 Ent1 := Entity_Of_Unit (Unit1); 10656 Ent2 := Entity_Of_Unit (Unit2); 10657 10658 if Scope (Ent2) = Standard_Standard then 10659 Error_Msg_Sloc := Sloc (Current_Use_Clause (T)); 10660 Err_No := Clause1; 10661 10662 elsif Scope (Ent1) = Standard_Standard then 10663 Error_Msg_Sloc := Sloc (Id); 10664 Err_No := Clause2; 10665 10666 -- If both units are child units, we determine which one 10667 -- is the descendant by the scope distance to the 10668 -- ultimate parent unit. 10669 10670 else 10671 declare 10672 S1 : Entity_Id; 10673 S2 : Entity_Id; 10674 10675 begin 10676 S1 := Scope (Ent1); 10677 S2 := Scope (Ent2); 10678 while Present (S1) 10679 and then Present (S2) 10680 and then S1 /= Standard_Standard 10681 and then S2 /= Standard_Standard 10682 loop 10683 S1 := Scope (S1); 10684 S2 := Scope (S2); 10685 end loop; 10686 10687 if S1 = Standard_Standard then 10688 Error_Msg_Sloc := Sloc (Id); 10689 Err_No := Clause2; 10690 else 10691 Error_Msg_Sloc := Sloc (Current_Use_Clause (T)); 10692 Err_No := Clause1; 10693 end if; 10694 end; 10695 end if; 10696 10697 if Parent (Id) /= Err_No then 10698 if Most_Descendant_Use_Clause 10699 (Err_No, Parent (Id)) = Parent (Id) 10700 then 10701 Error_Msg_Sloc := Sloc (Err_No); 10702 Err_No := Parent (Id); 10703 end if; 10704 10705 Error_Msg_NE -- CODEFIX 10706 ("& is already use-visible through previous " 10707 & "use_type_clause #??", Err_No, Id); 10708 end if; 10709 10710 -- Case where current use_type_clause and use_type_clause 10711 -- for the type are not both at the compilation unit level. 10712 -- In this case we don't have location information. 10713 10714 else 10715 Error_Msg_NE -- CODEFIX 10716 ("& is already use-visible through previous " 10717 & "use_type_clause??", Id, T); 10718 end if; 10719 end Use_Clause_Known; 10720 10721 -- Here if Current_Use_Clause is not set for T, another case where 10722 -- we do not have the location information available. 10723 10724 else 10725 Error_Msg_NE -- CODEFIX 10726 ("& is already use-visible through previous " 10727 & "use_type_clause??", Id, T); 10728 end if; 10729 10730 -- The package where T is declared is already used 10731 10732 elsif In_Use (Scope (T)) then 10733 -- Due to expansion of contracts we could be attempting to issue 10734 -- a spurious warning - so verify there is a previous use clause. 10735 10736 if Current_Use_Clause (Scope (T)) /= 10737 Find_First_Use (Current_Use_Clause (Scope (T))) 10738 then 10739 Error_Msg_Sloc := 10740 Sloc (Find_First_Use (Current_Use_Clause (Scope (T)))); 10741 Error_Msg_NE -- CODEFIX 10742 ("& is already use-visible through package use clause #??", 10743 Id, T); 10744 end if; 10745 10746 -- The current scope is the package where T is declared 10747 10748 else 10749 Error_Msg_Node_2 := Scope (T); 10750 Error_Msg_NE -- CODEFIX 10751 ("& is already use-visible inside package &??", Id, T); 10752 end if; 10753 end if; 10754 end Use_One_Type; 10755 10756 ---------------- 10757 -- Write_Info -- 10758 ---------------- 10759 10760 procedure Write_Info is 10761 Id : Entity_Id := First_Entity (Current_Scope); 10762 10763 begin 10764 -- No point in dumping standard entities 10765 10766 if Current_Scope = Standard_Standard then 10767 return; 10768 end if; 10769 10770 Write_Str ("========================================================"); 10771 Write_Eol; 10772 Write_Str (" Defined Entities in "); 10773 Write_Name (Chars (Current_Scope)); 10774 Write_Eol; 10775 Write_Str ("========================================================"); 10776 Write_Eol; 10777 10778 if No (Id) then 10779 Write_Str ("-- none --"); 10780 Write_Eol; 10781 10782 else 10783 while Present (Id) loop 10784 Write_Entity_Info (Id, " "); 10785 Next_Entity (Id); 10786 end loop; 10787 end if; 10788 10789 if Scope (Current_Scope) = Standard_Standard then 10790 10791 -- Print information on the current unit itself 10792 10793 Write_Entity_Info (Current_Scope, " "); 10794 end if; 10795 10796 Write_Eol; 10797 end Write_Info; 10798 10799 -------- 10800 -- ws -- 10801 -------- 10802 10803 procedure ws is 10804 S : Entity_Id; 10805 begin 10806 for J in reverse 1 .. Scope_Stack.Last loop 10807 S := Scope_Stack.Table (J).Entity; 10808 Write_Int (Int (S)); 10809 Write_Str (" === "); 10810 Write_Name (Chars (S)); 10811 Write_Eol; 10812 end loop; 10813 end ws; 10814 10815 -------- 10816 -- we -- 10817 -------- 10818 10819 procedure we (S : Entity_Id) is 10820 E : Entity_Id; 10821 begin 10822 E := First_Entity (S); 10823 while Present (E) loop 10824 Write_Int (Int (E)); 10825 Write_Str (" === "); 10826 Write_Name (Chars (E)); 10827 Write_Eol; 10828 Next_Entity (E); 10829 end loop; 10830 end we; 10831end Sem_Ch8; 10832