1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ P R A G -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2015, 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-- Pragma handling is isolated in a separate package 27-- (logically this processing belongs in chapter 4) 28 29with Namet; use Namet; 30with Opt; use Opt; 31with Snames; use Snames; 32with Types; use Types; 33 34package Sem_Prag is 35 36 -- The following table lists all pragmas that emulate an Ada 2012 aspect 37 38 Aspect_Specifying_Pragma : constant array (Pragma_Id) of Boolean := 39 (Pragma_Abstract_State => True, 40 Pragma_All_Calls_Remote => True, 41 Pragma_Annotate => True, 42 Pragma_Async_Readers => True, 43 Pragma_Async_Writers => True, 44 Pragma_Asynchronous => True, 45 Pragma_Atomic => True, 46 Pragma_Atomic_Components => True, 47 Pragma_Attach_Handler => True, 48 Pragma_Constant_After_Elaboration => True, 49 Pragma_Contract_Cases => True, 50 Pragma_Convention => True, 51 Pragma_CPU => True, 52 Pragma_Default_Initial_Condition => True, 53 Pragma_Default_Storage_Pool => True, 54 Pragma_Depends => True, 55 Pragma_Discard_Names => True, 56 Pragma_Dispatching_Domain => True, 57 Pragma_Effective_Reads => True, 58 Pragma_Effective_Writes => True, 59 Pragma_Elaborate_Body => True, 60 Pragma_Export => True, 61 Pragma_Extensions_Visible => True, 62 Pragma_Favor_Top_Level => True, 63 Pragma_Ghost => True, 64 Pragma_Global => True, 65 Pragma_Import => True, 66 Pragma_Independent => True, 67 Pragma_Independent_Components => True, 68 Pragma_Initial_Condition => True, 69 Pragma_Initializes => True, 70 Pragma_Inline => True, 71 Pragma_Inline_Always => True, 72 Pragma_Interrupt_Handler => True, 73 Pragma_Interrupt_Priority => True, 74 Pragma_Invariant => True, 75 Pragma_Linker_Section => True, 76 Pragma_Lock_Free => True, 77 Pragma_No_Elaboration_Code_All => True, 78 Pragma_No_Return => True, 79 Pragma_Obsolescent => True, 80 Pragma_Pack => True, 81 Pragma_Part_Of => True, 82 Pragma_Persistent_BSS => True, 83 Pragma_Post => True, 84 Pragma_Post_Class => True, 85 Pragma_Postcondition => True, 86 Pragma_Pre => True, 87 Pragma_Pre_Class => True, 88 Pragma_Precondition => True, 89 Pragma_Predicate => True, 90 Pragma_Preelaborable_Initialization => True, 91 Pragma_Preelaborate => True, 92 Pragma_Priority => True, 93 Pragma_Pure => True, 94 Pragma_Pure_Function => True, 95 Pragma_Refined_Depends => True, 96 Pragma_Refined_Global => True, 97 Pragma_Refined_Post => True, 98 Pragma_Refined_State => True, 99 Pragma_Relative_Deadline => True, 100 Pragma_Remote_Access_Type => True, 101 Pragma_Remote_Call_Interface => True, 102 Pragma_Remote_Types => True, 103 Pragma_Shared => True, 104 Pragma_Shared_Passive => True, 105 Pragma_Simple_Storage_Pool_Type => True, 106 Pragma_SPARK_Mode => True, 107 Pragma_Storage_Size => True, 108 Pragma_Suppress => True, 109 Pragma_Suppress_Debug_Info => True, 110 Pragma_Suppress_Initialization => True, 111 Pragma_Test_Case => True, 112 Pragma_Thread_Local_Storage => True, 113 Pragma_Type_Invariant => True, 114 Pragma_Unchecked_Union => True, 115 Pragma_Universal_Aliasing => True, 116 Pragma_Universal_Data => True, 117 Pragma_Unmodified => True, 118 Pragma_Unreferenced => True, 119 Pragma_Unreferenced_Objects => True, 120 Pragma_Unsuppress => True, 121 Pragma_Volatile => True, 122 Pragma_Volatile_Components => True, 123 Pragma_Volatile_Full_Access => True, 124 Pragma_Warnings => True, 125 others => False); 126 127 -- The following table lists all pragmas that act as an assertion 128 -- expression. 129 130 Assertion_Expression_Pragma : constant array (Pragma_Id) of Boolean := 131 (Pragma_Assert => True, 132 Pragma_Assert_And_Cut => True, 133 Pragma_Assume => True, 134 Pragma_Check => True, 135 Pragma_Contract_Cases => True, 136 Pragma_Default_Initial_Condition => True, 137 Pragma_Initial_Condition => True, 138 Pragma_Invariant => True, 139 Pragma_Loop_Invariant => True, 140 Pragma_Loop_Variant => True, 141 Pragma_Post => True, 142 Pragma_Post_Class => True, 143 Pragma_Postcondition => True, 144 Pragma_Pre => True, 145 Pragma_Pre_Class => True, 146 Pragma_Precondition => True, 147 Pragma_Predicate => True, 148 Pragma_Refined_Post => True, 149 Pragma_Test_Case => True, 150 Pragma_Type_Invariant => True, 151 Pragma_Type_Invariant_Class => True, 152 others => False); 153 154 -- The following table lists all the implementation-defined pragmas that 155 -- should apply to the anonymous object produced by the analysis of a 156 -- single protected or task type. The table should be synchronized with 157 -- Aspect_On_Anonymous_Object_OK in unit Aspects. 158 159 Pragma_On_Anonymous_Object_OK : constant array (Pragma_Id) of Boolean := 160 (Pragma_Depends => True, 161 Pragma_Global => True, 162 Pragma_Part_Of => True, 163 others => False); 164 165 -- The following table lists all the implementation-defined pragmas that 166 -- may apply to a body stub (no language defined pragmas apply). The table 167 -- should be synchronized with Aspect_On_Body_Or_Stub_OK in unit Aspects. 168 169 Pragma_On_Body_Or_Stub_OK : constant array (Pragma_Id) of Boolean := 170 (Pragma_Refined_Depends => True, 171 Pragma_Refined_Global => True, 172 Pragma_Refined_Post => True, 173 Pragma_SPARK_Mode => True, 174 Pragma_Warnings => True, 175 others => False); 176 177 ----------------- 178 -- Subprograms -- 179 ----------------- 180 181 procedure Analyze_Pragma (N : Node_Id); 182 -- Analyze procedure for pragma reference node N 183 184 procedure Analyze_Contract_Cases_In_Decl_Part 185 (N : Node_Id; 186 Freeze_Id : Entity_Id := Empty); 187 -- Perform full analysis of delayed pragma Contract_Cases. Freeze_Id is the 188 -- entity of [generic] package body or [generic] subprogram body which 189 -- caused "freezing" of the related contract where the pragma resides. 190 191 procedure Analyze_Depends_In_Decl_Part (N : Node_Id); 192 -- Perform full analysis of delayed pragma Depends. This routine is also 193 -- capable of performing basic analysis of pragma Refined_Depends. 194 195 procedure Analyze_External_Property_In_Decl_Part 196 (N : Node_Id; 197 Expr_Val : out Boolean); 198 -- Perform full analysis of delayed pragmas Async_Readers, Async_Writers, 199 -- Effective_Reads and Effective_Writes. Flag Expr_Val contains the Boolean 200 -- argument of the pragma or a default True if no argument is present. 201 202 procedure Analyze_Global_In_Decl_Part (N : Node_Id); 203 -- Perform full analysis of delayed pragma Global. This routine is also 204 -- capable of performing basic analysis of pragma Refind_Global. 205 206 procedure Analyze_Initial_Condition_In_Decl_Part (N : Node_Id); 207 -- Perform full analysis of delayed pragma Initial_Condition 208 209 procedure Analyze_Initializes_In_Decl_Part (N : Node_Id); 210 -- Perform full analysis of delayed pragma Initializes 211 212 procedure Analyze_Part_Of_In_Decl_Part 213 (N : Node_Id; 214 Freeze_Id : Entity_Id := Empty); 215 -- Perform full analysis of delayed pragma Part_Of. Freeze_Id is the entity 216 -- of [generic] package body or [generic] subprogram body which caused the 217 -- "freezing" of the related contract where the pragma resides. 218 219 procedure Analyze_Pre_Post_Condition_In_Decl_Part 220 (N : Node_Id; 221 Freeze_Id : Entity_Id := Empty); 222 -- Perform full analysis of pragmas Precondition and Postcondition. 223 -- Freeze_Id denotes the entity of [generic] package body or [generic] 224 -- subprogram body which caused "freezing" of the related contract where 225 -- the pragma resides. 226 227 procedure Analyze_Refined_Depends_In_Decl_Part (N : Node_Id); 228 -- Preform full analysis of delayed pragma Refined_Depends. This routine 229 -- uses Analyze_Depends_In_Decl_Part as a starting point, then performs 230 -- various consistency checks between Depends and Refined_Depends. 231 232 procedure Analyze_Refined_Global_In_Decl_Part (N : Node_Id); 233 -- Perform full analysis of delayed pragma Refined_Global. This routine 234 -- uses Analyze_Global_In_Decl_Part as a starting point, then performs 235 -- various consistency checks between Global and Refined_Global. 236 237 procedure Analyze_Refined_State_In_Decl_Part 238 (N : Node_Id; 239 Freeze_Id : Entity_Id := Empty); 240 -- Perform full analysis of delayed pragma Refined_State. Freeze_Id denotes 241 -- the entity of [generic] package body or [generic] subprogram body which 242 -- caused "freezing" of the related contract where the pragma resides. 243 244 procedure Analyze_Test_Case_In_Decl_Part (N : Node_Id); 245 -- Perform preanalysis of pragma Test_Case 246 247 procedure Check_Applicable_Policy (N : Node_Id); 248 -- N is either an N_Aspect or an N_Pragma node. There are two cases. If 249 -- the name of the aspect or pragma is not one of those recognized as 250 -- an assertion kind by an Assertion_Policy pragma, then the call has 251 -- no effect. Note that in the case of a pragma derived from an aspect, 252 -- the name we use for the purpose of this procedure is the aspect name, 253 -- which may be different from the pragma name (e.g. Precondition for 254 -- Pre aspect). In addition, 'Class aspects are recognized (and the 255 -- corresponding special names used in the processing). 256 -- 257 -- If the name is a valid assertion kind name, then the Check_Policy pragma 258 -- chain is checked for a matching entry (or for an Assertion entry which 259 -- matches all possibilities). If a matching entry is found then the policy 260 -- is checked. If it is On or Check, then the Is_Checked flag is set in 261 -- the aspect or pragma node. If it is Off, Ignore, or Disable, then the 262 -- Is_Ignored flag is set in the aspect or pragma node. Additionally for 263 -- policy Disable, the Is_Disabled flag is set. 264 -- 265 -- If no matching Check_Policy pragma is found then the effect depends on 266 -- whether -gnata was used, if so, then the call has no effect, otherwise 267 -- Is_Ignored (but not Is_Disabled) is set True. 268 269 procedure Check_External_Properties 270 (Item : Node_Id; 271 AR : Boolean; 272 AW : Boolean; 273 ER : Boolean; 274 EW : Boolean); 275 -- Flags AR, AW, ER and EW denote the static values of external properties 276 -- Async_Readers, Async_Writers, Effective_Reads and Effective_Writes. Item 277 -- is the related variable or state. Ensure legality of the combination and 278 -- issue an error for an illegal combination. 279 280 function Check_Kind (Nam : Name_Id) return Name_Id; 281 -- This function is used in connection with pragmas Assert, Check, 282 -- and assertion aspects and pragmas, to determine if Check pragmas 283 -- (or corresponding assertion aspects or pragmas) are currently active 284 -- as determined by the presence of -gnata on the command line (which 285 -- sets the default), and the appearance of pragmas Check_Policy and 286 -- Assertion_Policy as configuration pragmas either in a configuration 287 -- pragma file, or at the start of the current unit, or locally given 288 -- Check_Policy and Assertion_Policy pragmas that are currently active. 289 -- 290 -- The value returned is one of the names Check, Ignore, Disable (On 291 -- returns Check, and Off returns Ignore). 292 -- 293 -- Note: for assertion kinds Pre'Class, Post'Class, Invariant'Class, 294 -- and Type_Invariant'Class, the name passed is Name_uPre, Name_uPost, 295 -- Name_uInvariant, or Name_uType_Invariant, which corresponds to _Pre, 296 -- _Post, _Invariant, or _Type_Invariant, which are special names used 297 -- in identifiers to represent these attribute references. 298 299 procedure Check_Missing_Part_Of (Item_Id : Entity_Id); 300 -- Determine whether the placement within the state space of an abstract 301 -- state, variable or package instantiation denoted by Item_Id requires the 302 -- use of indicator/option Part_Of. If this is the case, emit an error. 303 304 procedure Collect_Subprogram_Inputs_Outputs 305 (Subp_Id : Entity_Id; 306 Synthesize : Boolean := False; 307 Subp_Inputs : in out Elist_Id; 308 Subp_Outputs : in out Elist_Id; 309 Global_Seen : out Boolean); 310 -- Subsidiary to the analysis of pragmas Depends, Global, Refined_Depends 311 -- and Refined_Global. The routine is also used by GNATprove. Collect all 312 -- inputs and outputs of subprogram Subp_Id in lists Subp_Inputs (inputs) 313 -- and Subp_Outputs (outputs). The inputs and outputs are gathered from: 314 -- 1) The formal parameters of the subprogram 315 -- 2) The generic formal parameters of the generic subprogram 316 -- 3) The current instance of a concurrent type 317 -- 4) The items of pragma [Refined_]Global 318 -- or 319 -- 5) The items of pragma [Refined_]Depends if there is no pragma 320 -- [Refined_]Global present and flag Synthesize is set to True. 321 -- If the subprogram has no inputs and/or outputs, then the returned list 322 -- is No_Elist. Flag Global_Seen is set when the related subprogram has 323 -- pragma [Refined_]Global. 324 325 function Delay_Config_Pragma_Analyze (N : Node_Id) return Boolean; 326 -- N is a pragma appearing in a configuration pragma file. Most such 327 -- pragmas are analyzed when the file is read, before parsing and analyzing 328 -- the main unit. However, the analysis of certain pragmas results in 329 -- adding information to the compiled main unit, and this cannot be done 330 -- till the main unit is processed. Such pragmas return True from this 331 -- function and in Frontend pragmas where Delay_Config_Pragma_Analyze is 332 -- True have their analysis delayed until after the main program is parsed 333 -- and analyzed. 334 335 function Find_Related_Package_Or_Body 336 (Prag : Node_Id; 337 Do_Checks : Boolean := False) return Node_Id; 338 -- Subsidiary to the analysis of pragmas Abstract_State, Initial_Condition, 339 -- Initializes and Refined_State. Find the declaration of the related 340 -- package [body] subject to pragma Prag. The return value is either 341 -- N_Package_Declaration, N_Package_Body or Empty if the placement of 342 -- the pragma is illegal. If flag Do_Checks is set, the routine reports 343 -- duplicate pragmas. 344 345 function Find_Related_Declaration_Or_Body 346 (Prag : Node_Id; 347 Do_Checks : Boolean := False) return Node_Id; 348 -- Subsidiary to the analysis of pragmas 349 -- Contract_Cases 350 -- Depends 351 -- Extensions_Visible 352 -- Global 353 -- Post 354 -- Post_Class 355 -- Postcondition 356 -- Pre 357 -- Pre_Class 358 -- Precondition 359 -- Refined_Depends 360 -- Refined_Global 361 -- Refined_Post 362 -- Test_Case 363 -- as well as attributes 'Old and 'Result. Find the declaration of the 364 -- related entry, subprogram or task type [body] subject to pragma Prag. 365 -- If flag Do_Checks is set, the routine reports duplicate pragmas and 366 -- detects improper use of refinement pragmas in stand alone expression 367 -- functions. 368 369 function Get_Argument 370 (Prag : Node_Id; 371 Context_Id : Node_Id := Empty) return Node_Id; 372 -- Obtain the argument of pragma Prag depending on context and the nature 373 -- of the pragma. The argument is extracted in the following manner: 374 -- 375 -- When the pragma is generated from an aspect, return the corresponding 376 -- aspect for ASIS or when Context_Id denotes a generic unit. 377 -- 378 -- Otherwise return the first argument of Prag 379 -- 380 -- Context denotes the entity of the function, package or procedure where 381 -- Prag resides. 382 383 function Get_SPARK_Mode_From_Pragma (N : Node_Id) return SPARK_Mode_Type; 384 -- Given a pragma SPARK_Mode node, return corresponding mode id 385 386 procedure Initialize; 387 -- Initializes data structures used for pragma processing. Must be called 388 -- before analyzing each new main source program. 389 390 function Is_Config_Static_String (Arg : Node_Id) return Boolean; 391 -- This is called for a configuration pragma that requires either string 392 -- literal or a concatenation of string literals. We cannot use normal 393 -- static string processing because it is too early in the case of the 394 -- pragma appearing in a configuration pragmas file. If Arg is of an 395 -- appropriate form, then this call obtains the string (doing any necessary 396 -- concatenations) and places it in Name_Buffer, setting Name_Len to its 397 -- length, and then returns True. If it is not of the correct form, then an 398 -- appropriate error message is posted, and False is returned. 399 400 function Is_Elaboration_SPARK_Mode (N : Node_Id) return Boolean; 401 -- Determine whether pragma SPARK_Mode appears in the statement part of a 402 -- package body. 403 404 function Is_Enabled_Pragma (Prag : Node_Id) return Boolean; 405 -- Determine whether a Boolean-like SPARK pragma Prag is enabled. To be 406 -- considered enabled, the pragma must either: 407 -- * Appear without its Boolean expression 408 -- * The Boolean expression evaluates to "True" 409 -- 410 -- Boolean-like SPARK pragmas differ from pure Boolean Ada pragmas in that 411 -- their optional Boolean expression must be static and cannot benefit from 412 -- forward references. The following are Boolean-like SPARK pragmas: 413 -- Async_Readers 414 -- Async_Writers 415 -- Constant_After_Elaboration 416 -- Effective_Reads 417 -- Effective_Writes 418 -- Extensions_Visible 419 -- Volatile_Function 420 421 function Is_Non_Significant_Pragma_Reference (N : Node_Id) return Boolean; 422 -- The node N is a node for an entity and the issue is whether the 423 -- occurrence is a reference for the purposes of giving warnings about 424 -- unreferenced variables. This function returns True if the reference is 425 -- not a reference from this point of view (e.g. the occurrence in a pragma 426 -- Pack) and False if it is a real reference (e.g. the occurrence in a 427 -- pragma Export); 428 429 function Is_Pragma_String_Literal (Par : Node_Id) return Boolean; 430 -- Given an N_Pragma_Argument_Association node, Par, which has the form of 431 -- an operator symbol, determines whether or not it should be treated as an 432 -- string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol. If 433 -- True is returned, the argument is converted to a string literal. If 434 -- False is returned, then the argument is treated as an entity reference 435 -- to the operator. 436 437 function Is_Private_SPARK_Mode (N : Node_Id) return Boolean; 438 -- Determine whether pragma SPARK_Mode appears in the private part of a 439 -- package. 440 441 function Is_Valid_Assertion_Kind (Nam : Name_Id) return Boolean; 442 -- Returns True if Nam is one of the names recognized as a valid assertion 443 -- kind by the Assertion_Policy pragma. Note that the 'Class cases are 444 -- represented by the corresponding special names Name_uPre, Name_uPost, 445 -- Name_uInvariant, and Name_uType_Invariant (_Pre, _Post, _Invariant, 446 -- and _Type_Invariant). 447 448 procedure Process_Compilation_Unit_Pragmas (N : Node_Id); 449 -- Called at the start of processing compilation unit N to deal with any 450 -- special issues regarding pragmas. In particular, we have to deal with 451 -- Suppress_All at this stage, since it can appear after the unit instead 452 -- of before (actually we allow it to appear anywhere). 453 454 procedure Relocate_Pragmas_To_Anonymous_Object 455 (Typ_Decl : Node_Id; 456 Obj_Decl : Node_Id); 457 -- Relocate all pragmas that appear in the visible declarations of task or 458 -- protected type declaration Typ_Decl after the declaration of anonymous 459 -- object Obj_Decl. Table Pragmas_On_Anonymous_Object_OK contains the list 460 -- of candidate pragmas. 461 462 procedure Relocate_Pragmas_To_Body 463 (Subp_Body : Node_Id; 464 Target_Body : Node_Id := Empty); 465 -- Resocate all pragmas that follow and apply to subprogram body Subp_Body 466 -- to its own declaration list. Candidate pragmas are classified in table 467 -- Pragma_On_Body_Or_Stub_OK. If Target_Body is set, the pragma are moved 468 -- to the declarations of Target_Body. This formal should be set when 469 -- dealing with subprogram body stubs or expression functions. 470 471 procedure Set_Encoded_Interface_Name (E : Entity_Id; S : Node_Id); 472 -- This routine is used to set an encoded interface name. The node S is 473 -- an N_String_Literal node for the external name to be set, and E is an 474 -- entity whose Interface_Name field is to be set. In the normal case where 475 -- S contains a name that is a valid C identifier, then S is simply set as 476 -- the value of the Interface_Name. Otherwise it is encoded as needed by 477 -- particular operating systems. See the body for details of the encoding. 478 479 function Test_Case_Arg 480 (Prag : Node_Id; 481 Arg_Nam : Name_Id; 482 From_Aspect : Boolean := False) return Node_Id; 483 -- Obtain argument "Name", "Mode", "Ensures" or "Requires" from Test_Case 484 -- pragma Prag as denoted by Arg_Nam. When From_Aspect is set, an attempt 485 -- is made to retrieve the argument from the corresponding aspect if there 486 -- is one. The returned argument has several formats: 487 -- 488 -- N_Pragma_Argument_Association if retrieved directly from the pragma 489 -- 490 -- N_Component_Association if retrieved from the corresponding aspect and 491 -- the argument appears in a named association form. 492 -- 493 -- An arbitrary expression if retrieved from the corresponding aspect and 494 -- the argument appears in positional form. 495 -- 496 -- Empty if there is no such argument 497 498end Sem_Prag; 499