1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2012, 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 26-------------------------------------- 27-- Semantic Analysis: General Model -- 28-------------------------------------- 29 30-- Semantic processing involves 3 phases which are highly intertwined 31-- (i.e. mutually recursive): 32 33-- Analysis implements the bulk of semantic analysis such as 34-- name analysis and type resolution for declarations, 35-- instructions and expressions. The main routine 36-- driving this process is procedure Analyze given below. 37-- This analysis phase is really a bottom up pass that is 38-- achieved during the recursive traversal performed by the 39-- Analyze_... procedures implemented in the sem_* packages. 40-- For expressions this phase determines unambiguous types 41-- and collects sets of possible types where the 42-- interpretation is potentially ambiguous. 43 44-- Resolution is carried out only for expressions to finish type 45-- resolution that was initiated but not necessarily 46-- completed during analysis (because of overloading 47-- ambiguities). Specifically, after completing the bottom 48-- up pass carried out during analysis for expressions, the 49-- Resolve routine (see the spec of sem_res for more info) 50-- is called to perform a top down resolution with 51-- recursive calls to itself to resolve operands. 52 53-- Expansion if we are not generating code this phase is a no-op. 54-- otherwise this phase expands, i.e. transforms, original 55-- declaration, expressions or instructions into simpler 56-- structures that can be handled by the back-end. This 57-- phase is also in charge of generating code which is 58-- implicit in the original source (for instance for 59-- default initializations, controlled types, etc.) 60-- There are two separate instances where expansion is 61-- invoked. For declarations and instructions, expansion is 62-- invoked just after analysis since no resolution needs 63-- to be performed. For expressions, expansion is done just 64-- after resolution. In both cases expansion is done from the 65-- bottom up just before the end of Analyze for instructions 66-- and declarations or the call to Resolve for expressions. 67-- The main routine driving expansion is Expand. 68-- See the spec of Expander for more details. 69 70-- To summarize, in normal code generation mode we recursively traverse the 71-- abstract syntax tree top-down performing semantic analysis bottom 72-- up. For instructions and declarations, before the call to the Analyze 73-- routine completes we perform expansion since at that point we have all 74-- semantic information needed. For expression nodes, after the call to 75-- Analysis terminates we invoke the Resolve routine to transmit top-down 76-- the type that was gathered by Analyze which will resolve possible 77-- ambiguities in the expression. Just before the call to Resolve 78-- terminates, the expression can be expanded since all the semantic 79-- information is available at that point. 80 81-- If we are not generating code then the expansion phase is a no-op 82 83-- When generating code there are a number of exceptions to the basic 84-- Analysis-Resolution-Expansion model for expressions. The most prominent 85-- examples are the handling of default expressions and aggregates. 86 87----------------------------------------------------------------------- 88-- Handling of Default and Per-Object Expressions (Spec-Expressions) -- 89----------------------------------------------------------------------- 90 91-- The default expressions in component declarations and in procedure 92-- specifications (but not the ones in object declarations) are quite tricky 93-- to handle. The problem is that some processing is required at the point 94-- where the expression appears: 95 96-- visibility analysis (including user defined operators) 97-- freezing of static expressions 98 99-- but other processing must be deferred until the enclosing entity (record or 100-- procedure specification) is frozen: 101 102-- freezing of any other types in the expression expansion 103-- generation of code 104 105-- A similar situation occurs with the argument of priority and interrupt 106-- priority pragmas that appear in task and protected definition specs and 107-- other cases of per-object expressions (see RM 3.8(18)). 108 109-- Another similar case is the conditions in precondition and postcondition 110-- pragmas that appear with subprogram specifications rather than in the body. 111 112-- Collectively we call these Spec_Expressions. The routine that performs the 113-- special analysis is called Analyze_Spec_Expression. 114 115-- Expansion has to be deferred since you can't generate code for expressions 116-- that reference types that have not been frozen yet. As an example, consider 117-- the following: 118 119-- type x is delta 0.5 range -10.0 .. +10.0; 120-- ... 121-- type q is record 122-- xx : x := y * z; 123-- end record; 124 125-- for x'small use 0.25 126 127-- The expander is in charge of dealing with fixed-point, and of course the 128-- small declaration, which is not too late, since the declaration of type q 129-- does *not* freeze type x, definitely affects the expanded code. 130 131-- Another reason that we cannot expand early is that expansion can generate 132-- range checks. These range checks need to be inserted not at the point of 133-- definition but at the point of use. The whole point here is that the value 134-- of the expression cannot be obtained at the point of declaration, only at 135-- the point of use. 136 137-- Generally our model is to combine analysis resolution and expansion, but 138-- this is the one case where this model falls down. Here is how we patch 139-- it up without causing too much distortion to our basic model. 140 141-- A switch (In_Spec_Expression) is set to show that we are in the initial 142-- occurrence of a default expression. The analyzer is then called on this 143-- expression with the switch set true. Analysis and resolution proceed almost 144-- as usual, except that Freeze_Expression will not freeze non-static 145-- expressions if this switch is set, and the call to Expand at the end of 146-- resolution is skipped. This also skips the code that normally sets the 147-- Analyzed flag to True. The result is that when we are done the tree is 148-- still marked as unanalyzed, but all types for static expressions are frozen 149-- as required, and all entities of variables have been recorded. We then turn 150-- off the switch, and later on reanalyze the expression with the switch off. 151-- The effect is that this second analysis freezes the rest of the types as 152-- required, and generates code but visibility analysis is not repeated since 153-- all the entities are marked. 154 155-- The second analysis (the one that generates code) is in the context 156-- where the code is required. For a record field default, this is in the 157-- initialization procedure for the record and for a subprogram default 158-- parameter, it is at the point the subprogram is frozen. For a priority or 159-- storage size pragma it is in the context of the Init_Proc for the task or 160-- protected object. For a pre/postcondition pragma it is in the body when 161-- code for the pragma is generated. 162 163------------------ 164-- Pre-Analysis -- 165------------------ 166 167-- For certain kind of expressions, such as aggregates, we need to defer 168-- expansion of the aggregate and its inner expressions after the whole 169-- set of expressions appearing inside the aggregate have been analyzed. 170-- Consider, for instance the following example: 171-- 172-- (1 .. 100 => new Thing (Function_Call)) 173-- 174-- The normal Analysis-Resolution-Expansion mechanism where expansion of the 175-- children is performed before expansion of the parent does not work if the 176-- code generated for the children by the expander needs to be evaluated 177-- repeatedly (for instance in the above aggregate "new Thing (Function_Call)" 178-- needs to be called 100 times.) 179 180-- The reason why this mechanism does not work is that, the expanded code for 181-- the children is typically inserted above the parent and thus when the 182-- father gets expanded no re-evaluation takes place. For instance in the case 183-- of aggregates if "new Thing (Function_Call)" is expanded before of the 184-- aggregate the expanded code will be placed outside of the aggregate and 185-- when expanding the aggregate the loop from 1 to 100 will not surround the 186-- expanded code for "new Thing (Function_Call)". 187 188-- To remedy this situation we introduce a new flag which signals whether we 189-- want a full analysis (i.e. expansion is enabled) or a pre-analysis which 190-- performs Analysis and Resolution but no expansion. 191 192-- After the complete pre-analysis of an expression has been carried out we 193-- can transform the expression and then carry out the full three stage 194-- (Analyze-Resolve-Expand) cycle on the transformed expression top-down so 195-- that the expansion of inner expressions happens inside the newly generated 196-- node for the parent expression. 197 198-- Note that the difference between processing of default expressions and 199-- pre-analysis of other expressions is that we do carry out freezing in 200-- the latter but not in the former (except for static scalar expressions). 201-- The routine that performs preanalysis and corresponding resolution is 202-- called Preanalyze_And_Resolve and is in Sem_Res. 203 204with Alloc; 205with Einfo; use Einfo; 206with Table; 207with Types; use Types; 208 209package Sem is 210 211 ----------------------------- 212 -- Semantic Analysis Flags -- 213 ----------------------------- 214 215 Full_Analysis : Boolean := True; 216 -- Switch to indicate if we are doing a full analysis or a pre-analysis. 217 -- In normal analysis mode (Analysis-Expansion for instructions or 218 -- declarations) or (Analysis-Resolution-Expansion for expressions) this 219 -- flag is set. Note that if we are not generating code the expansion phase 220 -- merely sets the Analyzed flag to True in this case. If we are in 221 -- Pre-Analysis mode (see above) this flag is set to False then the 222 -- expansion phase is skipped. 223 -- 224 -- When this flag is False the flag Expander_Active is also False (the 225 -- Expander_Active flag defined in the spec of package Expander tells you 226 -- whether expansion is currently enabled). You should really regard this 227 -- as a read only flag. 228 229 In_Spec_Expression : Boolean := False; 230 -- Switch to indicate that we are in a spec-expression, as described 231 -- above. Note that this must be recursively saved on a Semantics call 232 -- since it is possible for the analysis of an expression to result in a 233 -- recursive call (e.g. to get the entity for System.Address as part of the 234 -- processing of an Address attribute reference). When this switch is True 235 -- then Full_Analysis above must be False. You should really regard this as 236 -- a read only flag. 237 238 In_Deleted_Code : Boolean := False; 239 -- If the condition in an if-statement is statically known, the branch 240 -- that is not taken is analyzed with expansion disabled, and the tree 241 -- is deleted after analysis. Itypes generated in deleted code must be 242 -- frozen from start, because the tree on which they depend will not 243 -- be available at the freeze point. 244 245 In_Assertion_Expr : Nat := 0; 246 -- This is set non-zero if we are within the expression of an assertion 247 -- pragma or aspect. It is a counter which is incremented at the start 248 -- of expanding such an expression, and decremented on completion of 249 -- expanding that expression. Probably a boolean would be good enough, 250 -- since we think that such expressions cannot nest, but that might not 251 -- be true in the future (e.g. if let expressions are added to Ada) so 252 -- we prepare for that future possibility by making it a counter. 253 254 In_Inlined_Body : Boolean := False; 255 -- Switch to indicate that we are analyzing and resolving an inlined body. 256 -- Type checking is disabled in this context, because types are known to be 257 -- compatible. This avoids problems with private types whose full view is 258 -- derived from private types. 259 260 Inside_A_Generic : Boolean := False; 261 -- This flag is set if we are processing a generic specification, generic 262 -- definition, or generic body. When this flag is True the Expander_Active 263 -- flag is False to disable any code expansion (see package Expander). Only 264 -- the generic processing can modify the status of this flag, any other 265 -- client should regard it as read-only. 266 -- Probably should be called Inside_A_Generic_Template ??? 267 268 Inside_Freezing_Actions : Nat := 0; 269 -- Flag indicating whether we are within a call to Expand_N_Freeze_Actions. 270 -- Non-zero means we are inside (it is actually a level counter to deal 271 -- with nested calls). Used to avoid traversing the tree each time a 272 -- subprogram call is processed to know if we must not clear all constant 273 -- indications from entities in the current scope. Only the expansion of 274 -- freezing nodes can modify the status of this flag, any other client 275 -- should regard it as read-only. 276 277 Unloaded_Subunits : Boolean := False; 278 -- This flag is set True if we have subunits that are not loaded. This 279 -- occurs when the main unit is a subunit, and contains lower level 280 -- subunits that are not loaded. We use this flag to suppress warnings 281 -- about unused variables, since these warnings are unreliable in this 282 -- case. We could perhaps do a more accurate job and retain some of the 283 -- warnings, but it is quite a tricky job. 284 285 ----------------------------------- 286 -- Handling of Check Suppression -- 287 ----------------------------------- 288 289 -- There are two kinds of suppress checks: scope based suppress checks, 290 -- and entity based suppress checks. 291 292 -- Scope based suppress checks for the predefined checks (from initial 293 -- command line arguments, or from Suppress pragmas not including an entity 294 -- name) are recorded in the Sem.Scope_Suppress variable, and all that 295 -- is necessary is to save the state of this variable on scope entry, and 296 -- restore it on scope exit. This mechanism allows for fast checking of the 297 -- scope suppress state without needing complex data structures. 298 299 -- Entity based checks, from Suppress/Unsuppress pragmas giving an 300 -- Entity_Id and scope based checks for non-predefined checks (introduced 301 -- using pragma Check_Name), are handled as follows. If a suppress or 302 -- unsuppress pragma is encountered for a given entity, then the flag 303 -- Checks_May_Be_Suppressed is set in the entity and an entry is made in 304 -- either the Local_Entity_Suppress stack (case of pragma that appears in 305 -- other than a package spec), or in the Global_Entity_Suppress stack (case 306 -- of pragma that appears in a package spec, which is by the rule of RM 307 -- 11.5(7) applicable throughout the life of the entity). Similarly, a 308 -- Suppress/Unsuppress pragma for a non-predefined check which does not 309 -- specify an entity is also stored in one of these stacks. 310 311 -- If the Checks_May_Be_Suppressed flag is set in an entity then the 312 -- procedure is to search first the local and then the global suppress 313 -- stacks (we search these in reverse order, top element first). The only 314 -- other point is that we have to make sure that we have proper nested 315 -- interaction between such specific pragmas and locally applied general 316 -- pragmas applying to all entities. This is achieved by including in the 317 -- Local_Entity_Suppress table dummy entries with an empty Entity field 318 -- that are applicable to all entities. A similar search is needed for any 319 -- non-predefined check even if no specific entity is involved. 320 321 Scope_Suppress : Suppress_Record; 322 -- This variable contains the current scope based settings of the suppress 323 -- switches. It is initialized from Suppress_Options in Gnat1drv, and then 324 -- modified by pragma Suppress. On entry to each scope, the current setting 325 -- is saved on the scope stack, and then restored on exit from the scope. 326 -- This record may be rapidly checked to determine the current status of 327 -- a check if no specific entity is involved or if the specific entity 328 -- involved is one for which no specific Suppress/Unsuppress pragma has 329 -- been set (as indicated by the Checks_May_Be_Suppressed flag being set). 330 331 -- This scheme is a little complex, but serves the purpose of enabling 332 -- a very rapid check in the common case where no entity specific pragma 333 -- applies, and gives the right result when such pragmas are used even 334 -- in complex cases of nested Suppress and Unsuppress pragmas. 335 336 -- The Local_Entity_Suppress and Global_Entity_Suppress stacks are handled 337 -- using dynamic allocation and linked lists. We do not often use this 338 -- approach in the compiler (preferring to use extensible tables instead). 339 -- The reason we do it here is that scope stack entries save a pointer to 340 -- the current local stack top, which is also saved and restored on scope 341 -- exit. Furthermore for processing of generics we save pointers to the 342 -- top of the stack, so that the local stack is actually a tree of stacks 343 -- rather than a single stack, a structure that is easy to represent using 344 -- linked lists, but impossible to represent using a single table. Note 345 -- that because of the generic issue, we never release entries in these 346 -- stacks, but that's no big deal, since we are unlikely to have a huge 347 -- number of Suppress/Unsuppress entries in a single compilation. 348 349 type Suppress_Stack_Entry; 350 type Suppress_Stack_Entry_Ptr is access all Suppress_Stack_Entry; 351 352 type Suppress_Stack_Entry is record 353 Entity : Entity_Id; 354 -- Entity to which the check applies, or Empty for a check that has 355 -- no entity name (and thus applies to all entities). 356 357 Check : Check_Id; 358 -- Check which is set (can be All_Checks for the All_Checks case) 359 360 Suppress : Boolean; 361 -- Set True for Suppress, and False for Unsuppress 362 363 Prev : Suppress_Stack_Entry_Ptr; 364 -- Pointer to previous entry on stack 365 366 Next : Suppress_Stack_Entry_Ptr; 367 -- All allocated Suppress_Stack_Entry records are chained together in 368 -- a linked list whose head is Suppress_Stack_Entries, and the Next 369 -- field is used as a forward pointer (null ends the list). This is 370 -- used to free all entries in Sem.Init (which will be important if 371 -- we ever setup the compiler to be reused). 372 end record; 373 374 Suppress_Stack_Entries : Suppress_Stack_Entry_Ptr := null; 375 -- Pointer to linked list of records (see comments for Next above) 376 377 Local_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr; 378 -- Pointer to top element of local suppress stack. This is the entry that 379 -- is saved and restored in the scope stack, and also saved for generic 380 -- body expansion. 381 382 Global_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr; 383 -- Pointer to top element of global suppress stack 384 385 procedure Push_Local_Suppress_Stack_Entry 386 (Entity : Entity_Id; 387 Check : Check_Id; 388 Suppress : Boolean); 389 -- Push a new entry on to the top of the local suppress stack, updating 390 -- the value in Local_Suppress_Stack_Top; 391 392 procedure Push_Global_Suppress_Stack_Entry 393 (Entity : Entity_Id; 394 Check : Check_Id; 395 Suppress : Boolean); 396 -- Push a new entry on to the top of the global suppress stack, updating 397 -- the value in Global_Suppress_Stack_Top; 398 399 ----------------- 400 -- Scope Stack -- 401 ----------------- 402 403 -- The scope stack indicates the declarative regions that are currently 404 -- being processed (analyzed and/or expanded). The scope stack is one of 405 -- the basic visibility structures in the compiler: entities that are 406 -- declared in a scope that is currently on the scope stack are immediately 407 -- visible (leaving aside issues of hiding and overloading). 408 409 -- Initially, the scope stack only contains an entry for package Standard. 410 -- When a compilation unit, subprogram unit, block or declarative region 411 -- is being processed, the corresponding entity is pushed on the scope 412 -- stack. It is removed after the processing step is completed. A given 413 -- entity can be placed several times on the scope stack, for example 414 -- when processing derived type declarations, freeze nodes, etc. The top 415 -- of the scope stack is the innermost scope currently being processed. 416 -- It is obtained through function Current_Scope. After a compilation unit 417 -- has been processed, the scope stack must contain only Standard. 418 -- The predicate In_Open_Scopes specifies whether a scope is currently 419 -- on the scope stack. 420 421 -- This model is complicated by the need to compile units on the fly, in 422 -- the middle of the compilation of other units. This arises when compiling 423 -- instantiations, and when compiling run-time packages obtained through 424 -- rtsfind. Given that the scope stack is a single static and global 425 -- structure (not originally designed for the recursive processing required 426 -- by rtsfind for example) additional machinery is needed to indicate what 427 -- is currently being compiled. As a result, the scope stack holds several 428 -- contiguous sections that correspond to the compilation of a given 429 -- compilation unit. These sections are separated by distinct occurrences 430 -- of package Standard. The currently active section of the scope stack 431 -- goes from the current scope to the first (innermost) occurrence of 432 -- Standard, which is additionally marked with the flag 433 -- Is_Active_Stack_Base. The basic visibility routine (Find_Direct_Name, in 434 -- Sem_Ch8) uses this contiguous section of the scope stack to determine 435 -- whether a given entity is or is not visible at a point. In_Open_Scopes 436 -- only examines the currently active section of the scope stack. 437 438 -- Similar complications arise when processing child instances. These 439 -- must be compiled in the context of parent instances, and therefore the 440 -- parents must be pushed on the stack before compiling the child, and 441 -- removed afterwards. Routines Save_Scope_Stack and Restore_Scope_Stack 442 -- are used to set/reset the visibility of entities declared in scopes 443 -- that are currently on the scope stack, and are used when compiling 444 -- instance bodies on the fly. 445 446 -- It is clear in retrospect that all semantic processing and visibility 447 -- structures should have been fully recursive. The rtsfind mechanism, 448 -- and the complexities brought about by subunits and by generic child 449 -- units and their instantiations, have led to a hybrid model that carries 450 -- more state than one would wish. 451 452 type Scope_Stack_Entry is record 453 Entity : Entity_Id; 454 -- Entity representing the scope 455 456 Last_Subprogram_Name : String_Ptr; 457 -- Pointer to name of last subprogram body in this scope. Used for 458 -- testing proper alpha ordering of subprogram bodies in scope. 459 460 Save_Scope_Suppress : Suppress_Record; 461 -- Save contents of Scope_Suppress on entry 462 463 Save_Local_Suppress_Stack_Top : Suppress_Stack_Entry_Ptr; 464 -- Save contents of Local_Suppress_Stack on entry to restore on exit 465 466 Save_Check_Policy_List : Node_Id; 467 -- Save contents of Check_Policy_List on entry to restore on exit 468 469 Save_Default_Storage_Pool : Node_Id; 470 -- Save contents of Default_Storage_Pool on entry to restore on exit 471 472 Is_Transient : Boolean; 473 -- Marks transient scopes (see Exp_Ch7 body for details) 474 475 Previous_Visibility : Boolean; 476 -- Used when installing the parent(s) of the current compilation unit. 477 -- The parent may already be visible because of an ongoing compilation, 478 -- and the proper visibility must be restored on exit. The flag is 479 -- typically needed when the context of a child unit requires 480 -- compilation of a sibling. In other cases the flag is set to False. 481 -- See Sem_Ch10 (Install_Parents, Remove_Parents). 482 483 Node_To_Be_Wrapped : Node_Id; 484 -- Only used in transient scopes. Records the node which will 485 -- be wrapped by the transient block. 486 487 Actions_To_Be_Wrapped_Before : List_Id; 488 Actions_To_Be_Wrapped_After : List_Id; 489 -- Actions that have to be inserted at the start or at the end of a 490 -- transient block. Used to temporarily hold these actions until the 491 -- block is created, at which time the actions are moved to the block. 492 493 Pending_Freeze_Actions : List_Id; 494 -- Used to collect freeze entity nodes and associated actions that are 495 -- generated in an inner context but need to be analyzed outside, such 496 -- as records and initialization procedures. On exit from the scope, 497 -- this list of actions is inserted before the scope construct and 498 -- analyzed to generate the corresponding freeze processing and 499 -- elaboration of other associated actions. 500 501 First_Use_Clause : Node_Id; 502 -- Head of list of Use_Clauses in current scope. The list is built when 503 -- the declarations in the scope are processed. The list is traversed 504 -- on scope exit to undo the effect of the use clauses. 505 506 Component_Alignment_Default : Component_Alignment_Kind; 507 -- Component alignment to be applied to any record or array types that 508 -- are declared for which a specific component alignment pragma does not 509 -- set the alignment. 510 511 Is_Active_Stack_Base : Boolean; 512 -- Set to true only when entering the scope for Standard_Standard from 513 -- from within procedure Semantics. Indicates the base of the current 514 -- active set of scopes. Needed by In_Open_Scopes to handle cases where 515 -- Standard_Standard can be pushed anew on the scope stack to start a 516 -- new active section (see comment above). 517 518 end record; 519 520 package Scope_Stack is new Table.Table ( 521 Table_Component_Type => Scope_Stack_Entry, 522 Table_Index_Type => Int, 523 Table_Low_Bound => 0, 524 Table_Initial => Alloc.Scope_Stack_Initial, 525 Table_Increment => Alloc.Scope_Stack_Increment, 526 Table_Name => "Sem.Scope_Stack"); 527 528 ----------------- 529 -- Subprograms -- 530 ----------------- 531 532 procedure Initialize; 533 -- Initialize internal tables 534 535 procedure Lock; 536 -- Lock internal tables before calling back end 537 538 procedure Semantics (Comp_Unit : Node_Id); 539 -- This procedure is called to perform semantic analysis on the specified 540 -- node which is the N_Compilation_Unit node for the unit. 541 542 procedure Analyze (N : Node_Id); 543 procedure Analyze (N : Node_Id; Suppress : Check_Id); 544 -- This is the recursive procedure that is applied to individual nodes of 545 -- the tree, starting at the top level node (compilation unit node) and 546 -- then moving down the tree in a top down traversal. It calls individual 547 -- routines with names Analyze_xxx to analyze node xxx. Each of these 548 -- routines is responsible for calling Analyze on the components of the 549 -- subtree. 550 -- 551 -- Note: In the case of expression components (nodes whose Nkind is in 552 -- N_Subexpr), the call to Analyze does not complete the semantic analysis 553 -- of the node, since the type resolution cannot be completed until the 554 -- complete context is analyzed. The completion of the type analysis occurs 555 -- in the corresponding Resolve routine (see Sem_Res). 556 -- 557 -- Note: for integer and real literals, the analyzer sets the flag to 558 -- indicate that the result is a static expression. If the expander 559 -- generates a literal that does NOT correspond to a static expression, 560 -- e.g. by folding an expression whose value is known at compile-time, 561 -- but is not technically static, then the caller should reset the 562 -- Is_Static_Expression flag after analyzing but before resolving. 563 -- 564 -- If the Suppress argument is present, then the analysis is done 565 -- with the specified check suppressed (can be All_Checks to suppress 566 -- all checks). 567 568 procedure Analyze_List (L : List_Id); 569 procedure Analyze_List (L : List_Id; Suppress : Check_Id); 570 -- Analyzes each element of a list. If the Suppress argument is present, 571 -- then the analysis is done with the specified check suppressed (can 572 -- be All_Checks to suppress all checks). 573 574 procedure Copy_Suppress_Status 575 (C : Check_Id; 576 From : Entity_Id; 577 To : Entity_Id); 578 -- If From is an entity for which check C is explicitly suppressed 579 -- then also explicitly suppress the corresponding check in To. 580 581 procedure Insert_List_After_And_Analyze 582 (N : Node_Id; L : List_Id); 583 procedure Insert_List_After_And_Analyze 584 (N : Node_Id; L : List_Id; Suppress : Check_Id); 585 -- Inserts list L after node N using Nlists.Insert_List_After, and then, 586 -- after this insertion is complete, analyzes all the nodes in the list, 587 -- including any additional nodes generated by this analysis. If the list 588 -- is empty or No_List, the call has no effect. If the Suppress argument is 589 -- present, then the analysis is done with the specified check suppressed 590 -- (can be All_Checks to suppress all checks). 591 592 procedure Insert_List_Before_And_Analyze 593 (N : Node_Id; L : List_Id); 594 procedure Insert_List_Before_And_Analyze 595 (N : Node_Id; L : List_Id; Suppress : Check_Id); 596 -- Inserts list L before node N using Nlists.Insert_List_Before, and then, 597 -- after this insertion is complete, analyzes all the nodes in the list, 598 -- including any additional nodes generated by this analysis. If the list 599 -- is empty or No_List, the call has no effect. If the Suppress argument is 600 -- present, then the analysis is done with the specified check suppressed 601 -- (can be All_Checks to suppress all checks). 602 603 procedure Insert_After_And_Analyze 604 (N : Node_Id; M : Node_Id); 605 procedure Insert_After_And_Analyze 606 (N : Node_Id; M : Node_Id; Suppress : Check_Id); 607 -- Inserts node M after node N and then after the insertion is complete, 608 -- analyzes the inserted node and all nodes that are generated by 609 -- this analysis. If the node is empty, the call has no effect. If the 610 -- Suppress argument is present, then the analysis is done with the 611 -- specified check suppressed (can be All_Checks to suppress all checks). 612 613 procedure Insert_Before_And_Analyze 614 (N : Node_Id; M : Node_Id); 615 procedure Insert_Before_And_Analyze 616 (N : Node_Id; M : Node_Id; Suppress : Check_Id); 617 -- Inserts node M before node N and then after the insertion is complete, 618 -- analyzes the inserted node and all nodes that could be generated by 619 -- this analysis. If the node is empty, the call has no effect. If the 620 -- Suppress argument is present, then the analysis is done with the 621 -- specified check suppressed (can be All_Checks to suppress all checks). 622 623 function External_Ref_In_Generic (E : Entity_Id) return Boolean; 624 -- Return True if we are in the context of a generic and E is 625 -- external (more global) to it. 626 627 procedure Enter_Generic_Scope (S : Entity_Id); 628 -- Shall be called each time a Generic subprogram or package scope is 629 -- entered. S is the entity of the scope. 630 -- ??? At the moment, only called for package specs because this mechanism 631 -- is only used for avoiding freezing of external references in generics 632 -- and this can only be an issue if the outer generic scope is a package 633 -- spec (otherwise all external entities are already frozen) 634 635 procedure Exit_Generic_Scope (S : Entity_Id); 636 -- Shall be called each time a Generic subprogram or package scope is 637 -- exited. S is the entity of the scope. 638 -- ??? At the moment, only called for package specs exit. 639 640 function Explicit_Suppress (E : Entity_Id; C : Check_Id) return Boolean; 641 -- This function returns True if an explicit pragma Suppress for check C 642 -- is present in the package defining E. 643 644 procedure Preanalyze (N : Node_Id); 645 -- Performs a pre-analysis of node N. During pre-analysis no expansion is 646 -- carried out for N or its children. For more info on pre-analysis read 647 -- the spec of Sem. 648 649 generic 650 with procedure Action (Item : Node_Id); 651 procedure Walk_Library_Items; 652 -- Primarily for use by SofCheck Inspector. Must be called after semantic 653 -- analysis (and expansion) are complete. Walks each relevant library item, 654 -- calling Action for each, in an order such that one will not run across 655 -- forward references. Each Item passed to Action is the declaration or 656 -- body of a library unit, including generics and renamings. The first item 657 -- is the N_Package_Declaration node for package Standard. Bodies are not 658 -- included, except for the main unit itself, which always comes last. 659 -- 660 -- Item is never a subunit 661 -- 662 -- Item is never an instantiation. Instead, the instance declaration is 663 -- passed, and (if the instantiation is the main unit), the instance body. 664 665 -- Debugging: 666 667 function ss (Index : Int) return Scope_Stack_Entry; 668 pragma Export (Ada, ss); 669 -- "ss" = "scope stack"; returns the Index'th entry in the Scope_Stack 670 671 function sst return Scope_Stack_Entry; 672 pragma Export (Ada, sst); 673 -- "sst" = "scope stack top"; same as ss(Scope_Stack.Last) 674 675end Sem; 676