1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- A S P E C T S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2010-2015, 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. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This package defines the aspects that are recognized by GNAT in aspect 33-- specifications. It also contains the subprograms for storing/retrieving 34-- aspect specifications from the tree. The semantic processing for aspect 35-- specifications is found in Sem_Ch13.Analyze_Aspect_Specifications. 36 37------------------------ 38-- Adding New Aspects -- 39------------------------ 40 41-- In general, each aspect should have a corresponding pragma, so that the 42-- newly developed functionality is available for Ada versions < Ada 2012. 43-- When both are defined, it is convenient to first transform the aspect into 44-- an equivalent pragma in Sem_Ch13.Analyze_Aspect_Specifications, and then 45-- analyze the pragma in Sem_Prag.Analyze_Pragma. 46 47-- To add a new aspect, you need to do the following 48 49-- 1. Create a name in snames.ads-tmpl 50 51-- 2. Create a value in type Aspect_Id in this unit 52 53-- 3. Add a value for the aspect in the global arrays defined in this unit 54 55-- 4. Add code for the aspect in Sem_Ch13.Analyze_Aspect_Specifications. 56-- This may involve adding some nodes to the tree to perform additional 57-- treatments later. 58 59-- 5. If the semantic analysis of expressions/names in the aspect should not 60-- occur at the point the aspect is defined, add code in the adequate 61-- semantic analysis procedure for the aspect. For example, this is the 62-- case for aspects Pre and Post on subprograms, which are pre-analyzed 63-- at the end of the declaration list to which the subprogram belongs, 64-- and fully analyzed (possibly with expansion) during the semantic 65-- analysis of subprogram bodies. 66 67with Namet; use Namet; 68with Snames; use Snames; 69with Types; use Types; 70 71package Aspects is 72 73 -- Type defining recognized aspects 74 75 type Aspect_Id is 76 (No_Aspect, -- Dummy entry for no aspect 77 Aspect_Abstract_State, -- GNAT 78 Aspect_Address, 79 Aspect_Alignment, 80 Aspect_Annotate, -- GNAT 81 Aspect_Attach_Handler, 82 Aspect_Bit_Order, 83 Aspect_Component_Size, 84 Aspect_Constant_Indexing, 85 Aspect_Contract_Cases, -- GNAT 86 Aspect_Convention, 87 Aspect_CPU, 88 Aspect_Default_Component_Value, 89 Aspect_Default_Initial_Condition, -- GNAT 90 Aspect_Default_Iterator, 91 Aspect_Default_Storage_Pool, 92 Aspect_Default_Value, 93 Aspect_Depends, -- GNAT 94 Aspect_Dimension, -- GNAT 95 Aspect_Dimension_System, -- GNAT 96 Aspect_Dispatching_Domain, 97 Aspect_Dynamic_Predicate, 98 Aspect_Extensions_Visible, -- GNAT 99 Aspect_External_Name, 100 Aspect_External_Tag, 101 Aspect_Ghost, -- GNAT 102 Aspect_Global, -- GNAT 103 Aspect_Implicit_Dereference, 104 Aspect_Initial_Condition, -- GNAT 105 Aspect_Initializes, -- GNAT 106 Aspect_Input, 107 Aspect_Interrupt_Priority, 108 Aspect_Invariant, -- GNAT 109 Aspect_Iterator_Element, 110 Aspect_Iterable, -- GNAT 111 Aspect_Link_Name, 112 Aspect_Linker_Section, -- GNAT 113 Aspect_Machine_Radix, 114 Aspect_Object_Size, -- GNAT 115 Aspect_Obsolescent, -- GNAT 116 Aspect_Output, 117 Aspect_Part_Of, -- GNAT 118 Aspect_Post, 119 Aspect_Postcondition, 120 Aspect_Pre, 121 Aspect_Precondition, 122 Aspect_Predicate, -- GNAT 123 Aspect_Priority, 124 Aspect_Read, 125 Aspect_Refined_Depends, -- GNAT 126 Aspect_Refined_Global, -- GNAT 127 Aspect_Refined_Post, -- GNAT 128 Aspect_Refined_State, -- GNAT 129 Aspect_Relative_Deadline, 130 Aspect_Scalar_Storage_Order, -- GNAT 131 Aspect_Simple_Storage_Pool, -- GNAT 132 Aspect_Size, 133 Aspect_Small, 134 Aspect_SPARK_Mode, -- GNAT 135 Aspect_Static_Predicate, 136 Aspect_Storage_Pool, 137 Aspect_Storage_Size, 138 Aspect_Stream_Size, 139 Aspect_Suppress, 140 Aspect_Synchronization, 141 Aspect_Test_Case, -- GNAT 142 Aspect_Type_Invariant, 143 Aspect_Unimplemented, -- GNAT 144 Aspect_Unsuppress, 145 Aspect_Value_Size, -- GNAT 146 Aspect_Variable_Indexing, 147 Aspect_Warnings, -- GNAT 148 Aspect_Write, 149 150 -- The following aspects correspond to library unit pragmas 151 152 Aspect_All_Calls_Remote, 153 Aspect_Elaborate_Body, 154 Aspect_No_Elaboration_Code_All, -- GNAT 155 Aspect_Preelaborate, 156 Aspect_Pure, 157 Aspect_Remote_Call_Interface, 158 Aspect_Remote_Types, 159 Aspect_Shared_Passive, 160 Aspect_Universal_Data, -- GNAT 161 162 -- Remaining aspects have a static boolean value that turns the aspect 163 -- on or off. They all correspond to pragmas, but are only converted to 164 -- the pragmas where the value is True. A value of False normally means 165 -- that the aspect is ignored, except in the case of derived types where 166 -- the aspect value is inherited from the parent, in which case, we do 167 -- not allow False if we inherit a True value from the parent. 168 169 Aspect_Async_Readers, -- GNAT 170 Aspect_Async_Writers, -- GNAT 171 Aspect_Asynchronous, 172 Aspect_Atomic, 173 Aspect_Atomic_Components, 174 Aspect_Discard_Names, 175 Aspect_Effective_Reads, -- GNAT 176 Aspect_Effective_Writes, -- GNAT 177 Aspect_Export, 178 Aspect_Favor_Top_Level, -- GNAT 179 Aspect_Independent, 180 Aspect_Independent_Components, 181 Aspect_Import, 182 Aspect_Inline, 183 Aspect_Inline_Always, -- GNAT 184 Aspect_Interrupt_Handler, 185 Aspect_Lock_Free, -- GNAT 186 Aspect_No_Return, 187 Aspect_No_Tagged_Streams, -- GNAT 188 Aspect_Pack, 189 Aspect_Persistent_BSS, -- GNAT 190 Aspect_Preelaborable_Initialization, 191 Aspect_Pure_Function, -- GNAT 192 Aspect_Remote_Access_Type, -- GNAT 193 Aspect_Shared, -- GNAT (equivalent to Atomic) 194 Aspect_Simple_Storage_Pool_Type, -- GNAT 195 Aspect_Suppress_Debug_Info, -- GNAT 196 Aspect_Suppress_Initialization, -- GNAT 197 Aspect_Thread_Local_Storage, -- GNAT 198 Aspect_Unchecked_Union, 199 Aspect_Universal_Aliasing, -- GNAT 200 Aspect_Unmodified, -- GNAT 201 Aspect_Unreferenced, -- GNAT 202 Aspect_Unreferenced_Objects, -- GNAT 203 Aspect_Volatile, 204 Aspect_Volatile_Components); 205 206 subtype Aspect_Id_Exclude_No_Aspect is 207 Aspect_Id range Aspect_Id'Succ (No_Aspect) .. Aspect_Id'Last; 208 -- Aspect_Id's excluding No_Aspect 209 210 -- The following array indicates aspects that accept 'Class 211 212 Class_Aspect_OK : constant array (Aspect_Id) of Boolean := 213 (Aspect_Input => True, 214 Aspect_Invariant => True, 215 Aspect_Output => True, 216 Aspect_Pre => True, 217 Aspect_Predicate => True, 218 Aspect_Post => True, 219 Aspect_Read => True, 220 Aspect_Write => True, 221 Aspect_Type_Invariant => True, 222 others => False); 223 224 -- The following array identifies all implementation defined aspects 225 226 Implementation_Defined_Aspect : constant array (Aspect_Id) of Boolean := 227 (Aspect_Abstract_State => True, 228 Aspect_Annotate => True, 229 Aspect_Async_Readers => True, 230 Aspect_Async_Writers => True, 231 Aspect_Contract_Cases => True, 232 Aspect_Depends => True, 233 Aspect_Dimension => True, 234 Aspect_Dimension_System => True, 235 Aspect_Effective_Reads => True, 236 Aspect_Effective_Writes => True, 237 Aspect_Extensions_Visible => True, 238 Aspect_Favor_Top_Level => True, 239 Aspect_Ghost => True, 240 Aspect_Global => True, 241 Aspect_Inline_Always => True, 242 Aspect_Invariant => True, 243 Aspect_Lock_Free => True, 244 Aspect_Object_Size => True, 245 Aspect_Persistent_BSS => True, 246 Aspect_Predicate => True, 247 Aspect_Pure_Function => True, 248 Aspect_Remote_Access_Type => True, 249 Aspect_Scalar_Storage_Order => True, 250 Aspect_Shared => True, 251 Aspect_Simple_Storage_Pool => True, 252 Aspect_Simple_Storage_Pool_Type => True, 253 Aspect_Suppress_Debug_Info => True, 254 Aspect_Suppress_Initialization => True, 255 Aspect_Thread_Local_Storage => True, 256 Aspect_Test_Case => True, 257 Aspect_Universal_Aliasing => True, 258 Aspect_Universal_Data => True, 259 Aspect_Unmodified => True, 260 Aspect_Unreferenced => True, 261 Aspect_Unreferenced_Objects => True, 262 Aspect_Value_Size => True, 263 Aspect_Warnings => True, 264 others => False); 265 266 -- The following array indicates aspects for which multiple occurrences of 267 -- the same aspect attached to the same declaration are allowed. 268 269 No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean := 270 (Aspect_Annotate => False, 271 Aspect_Test_Case => False, 272 others => True); 273 274 -- The following subtype defines aspects corresponding to library unit 275 -- pragmas, these can only validly appear as aspects for library units, 276 -- and result in a corresponding pragma being inserted immediately after 277 -- the occurrence of the aspect. 278 279 subtype Library_Unit_Aspects is 280 Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data; 281 282 -- The following subtype defines aspects accepting an optional static 283 -- boolean parameter indicating if the aspect should be active or 284 -- cancelling. If the parameter is missing the effective value is True, 285 -- enabling the aspect. If the parameter is present it must be a static 286 -- expression of type Standard.Boolean. If the value is True, then the 287 -- aspect is enabled. If it is False, the aspect is disabled. 288 289 subtype Boolean_Aspects is 290 Aspect_Id range Aspect_Async_Readers .. Aspect_Id'Last; 291 292 subtype Pre_Post_Aspects is 293 Aspect_Id range Aspect_Post .. Aspect_Precondition; 294 295 -- The following type is used for indicating allowed expression forms 296 297 type Aspect_Expression is 298 (Expression, -- Required expression 299 Name, -- Required name 300 Optional_Expression, -- Optional boolean expression 301 Optional_Name); -- Optional name 302 303 -- The following array indicates what argument type is required 304 305 Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression := 306 (No_Aspect => Optional_Expression, 307 Aspect_Abstract_State => Expression, 308 Aspect_Address => Expression, 309 Aspect_Alignment => Expression, 310 Aspect_Annotate => Expression, 311 Aspect_Attach_Handler => Expression, 312 Aspect_Bit_Order => Expression, 313 Aspect_Component_Size => Expression, 314 Aspect_Constant_Indexing => Name, 315 Aspect_Contract_Cases => Expression, 316 Aspect_Convention => Name, 317 Aspect_CPU => Expression, 318 Aspect_Default_Component_Value => Expression, 319 Aspect_Default_Initial_Condition => Optional_Expression, 320 Aspect_Default_Iterator => Name, 321 Aspect_Default_Storage_Pool => Expression, 322 Aspect_Default_Value => Expression, 323 Aspect_Depends => Expression, 324 Aspect_Dimension => Expression, 325 Aspect_Dimension_System => Expression, 326 Aspect_Dispatching_Domain => Expression, 327 Aspect_Dynamic_Predicate => Expression, 328 Aspect_Extensions_Visible => Optional_Expression, 329 Aspect_External_Name => Expression, 330 Aspect_External_Tag => Expression, 331 Aspect_Ghost => Optional_Expression, 332 Aspect_Global => Expression, 333 Aspect_Implicit_Dereference => Name, 334 Aspect_Initial_Condition => Expression, 335 Aspect_Initializes => Expression, 336 Aspect_Input => Name, 337 Aspect_Interrupt_Priority => Expression, 338 Aspect_Invariant => Expression, 339 Aspect_Iterable => Expression, 340 Aspect_Iterator_Element => Name, 341 Aspect_Link_Name => Expression, 342 Aspect_Linker_Section => Expression, 343 Aspect_Machine_Radix => Expression, 344 Aspect_Object_Size => Expression, 345 Aspect_Obsolescent => Optional_Expression, 346 Aspect_Output => Name, 347 Aspect_Part_Of => Expression, 348 Aspect_Post => Expression, 349 Aspect_Postcondition => Expression, 350 Aspect_Pre => Expression, 351 Aspect_Precondition => Expression, 352 Aspect_Predicate => Expression, 353 Aspect_Priority => Expression, 354 Aspect_Read => Name, 355 Aspect_Refined_Depends => Expression, 356 Aspect_Refined_Global => Expression, 357 Aspect_Refined_Post => Expression, 358 Aspect_Refined_State => Expression, 359 Aspect_Relative_Deadline => Expression, 360 Aspect_Scalar_Storage_Order => Expression, 361 Aspect_Simple_Storage_Pool => Name, 362 Aspect_Size => Expression, 363 Aspect_Small => Expression, 364 Aspect_SPARK_Mode => Optional_Name, 365 Aspect_Static_Predicate => Expression, 366 Aspect_Storage_Pool => Name, 367 Aspect_Storage_Size => Expression, 368 Aspect_Stream_Size => Expression, 369 Aspect_Suppress => Name, 370 Aspect_Synchronization => Name, 371 Aspect_Test_Case => Expression, 372 Aspect_Type_Invariant => Expression, 373 Aspect_Unimplemented => Optional_Expression, 374 Aspect_Unsuppress => Name, 375 Aspect_Value_Size => Expression, 376 Aspect_Variable_Indexing => Name, 377 Aspect_Warnings => Name, 378 Aspect_Write => Name, 379 380 Boolean_Aspects => Optional_Expression, 381 Library_Unit_Aspects => Optional_Expression); 382 383 ----------------------------------------- 384 -- Table Linking Names and Aspect_Id's -- 385 ----------------------------------------- 386 387 -- Table linking aspect names and id's 388 389 Aspect_Names : constant array (Aspect_Id) of Name_Id := 390 (No_Aspect => No_Name, 391 Aspect_Abstract_State => Name_Abstract_State, 392 Aspect_Address => Name_Address, 393 Aspect_Alignment => Name_Alignment, 394 Aspect_All_Calls_Remote => Name_All_Calls_Remote, 395 Aspect_Annotate => Name_Annotate, 396 Aspect_Async_Readers => Name_Async_Readers, 397 Aspect_Async_Writers => Name_Async_Writers, 398 Aspect_Asynchronous => Name_Asynchronous, 399 Aspect_Atomic => Name_Atomic, 400 Aspect_Atomic_Components => Name_Atomic_Components, 401 Aspect_Attach_Handler => Name_Attach_Handler, 402 Aspect_Bit_Order => Name_Bit_Order, 403 Aspect_Component_Size => Name_Component_Size, 404 Aspect_Constant_Indexing => Name_Constant_Indexing, 405 Aspect_Contract_Cases => Name_Contract_Cases, 406 Aspect_Convention => Name_Convention, 407 Aspect_CPU => Name_CPU, 408 Aspect_Default_Component_Value => Name_Default_Component_Value, 409 Aspect_Default_Initial_Condition => Name_Default_Initial_Condition, 410 Aspect_Default_Iterator => Name_Default_Iterator, 411 Aspect_Default_Storage_Pool => Name_Default_Storage_Pool, 412 Aspect_Default_Value => Name_Default_Value, 413 Aspect_Depends => Name_Depends, 414 Aspect_Dimension => Name_Dimension, 415 Aspect_Dimension_System => Name_Dimension_System, 416 Aspect_Discard_Names => Name_Discard_Names, 417 Aspect_Dispatching_Domain => Name_Dispatching_Domain, 418 Aspect_Dynamic_Predicate => Name_Dynamic_Predicate, 419 Aspect_Effective_Reads => Name_Effective_Reads, 420 Aspect_Effective_Writes => Name_Effective_Writes, 421 Aspect_Elaborate_Body => Name_Elaborate_Body, 422 Aspect_Export => Name_Export, 423 Aspect_Extensions_Visible => Name_Extensions_Visible, 424 Aspect_External_Name => Name_External_Name, 425 Aspect_External_Tag => Name_External_Tag, 426 Aspect_Favor_Top_Level => Name_Favor_Top_Level, 427 Aspect_Ghost => Name_Ghost, 428 Aspect_Global => Name_Global, 429 Aspect_Implicit_Dereference => Name_Implicit_Dereference, 430 Aspect_Import => Name_Import, 431 Aspect_Independent => Name_Independent, 432 Aspect_Independent_Components => Name_Independent_Components, 433 Aspect_Inline => Name_Inline, 434 Aspect_Inline_Always => Name_Inline_Always, 435 Aspect_Initial_Condition => Name_Initial_Condition, 436 Aspect_Initializes => Name_Initializes, 437 Aspect_Input => Name_Input, 438 Aspect_Interrupt_Handler => Name_Interrupt_Handler, 439 Aspect_Interrupt_Priority => Name_Interrupt_Priority, 440 Aspect_Invariant => Name_Invariant, 441 Aspect_Iterator_Element => Name_Iterator_Element, 442 Aspect_Iterable => Name_Iterable, 443 Aspect_Link_Name => Name_Link_Name, 444 Aspect_Linker_Section => Name_Linker_Section, 445 Aspect_Lock_Free => Name_Lock_Free, 446 Aspect_Machine_Radix => Name_Machine_Radix, 447 Aspect_No_Elaboration_Code_All => Name_No_Elaboration_Code_All, 448 Aspect_No_Return => Name_No_Return, 449 Aspect_No_Tagged_Streams => Name_No_Tagged_Streams, 450 Aspect_Object_Size => Name_Object_Size, 451 Aspect_Obsolescent => Name_Obsolescent, 452 Aspect_Output => Name_Output, 453 Aspect_Pack => Name_Pack, 454 Aspect_Part_Of => Name_Part_Of, 455 Aspect_Persistent_BSS => Name_Persistent_BSS, 456 Aspect_Post => Name_Post, 457 Aspect_Postcondition => Name_Postcondition, 458 Aspect_Pre => Name_Pre, 459 Aspect_Precondition => Name_Precondition, 460 Aspect_Predicate => Name_Predicate, 461 Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization, 462 Aspect_Preelaborate => Name_Preelaborate, 463 Aspect_Priority => Name_Priority, 464 Aspect_Pure => Name_Pure, 465 Aspect_Pure_Function => Name_Pure_Function, 466 Aspect_Read => Name_Read, 467 Aspect_Refined_Depends => Name_Refined_Depends, 468 Aspect_Refined_Global => Name_Refined_Global, 469 Aspect_Refined_Post => Name_Refined_Post, 470 Aspect_Refined_State => Name_Refined_State, 471 Aspect_Relative_Deadline => Name_Relative_Deadline, 472 Aspect_Remote_Access_Type => Name_Remote_Access_Type, 473 Aspect_Remote_Call_Interface => Name_Remote_Call_Interface, 474 Aspect_Remote_Types => Name_Remote_Types, 475 Aspect_Scalar_Storage_Order => Name_Scalar_Storage_Order, 476 Aspect_Shared => Name_Shared, 477 Aspect_Shared_Passive => Name_Shared_Passive, 478 Aspect_Simple_Storage_Pool => Name_Simple_Storage_Pool, 479 Aspect_Simple_Storage_Pool_Type => Name_Simple_Storage_Pool_Type, 480 Aspect_Size => Name_Size, 481 Aspect_Small => Name_Small, 482 Aspect_SPARK_Mode => Name_SPARK_Mode, 483 Aspect_Static_Predicate => Name_Static_Predicate, 484 Aspect_Storage_Pool => Name_Storage_Pool, 485 Aspect_Storage_Size => Name_Storage_Size, 486 Aspect_Stream_Size => Name_Stream_Size, 487 Aspect_Suppress => Name_Suppress, 488 Aspect_Suppress_Debug_Info => Name_Suppress_Debug_Info, 489 Aspect_Suppress_Initialization => Name_Suppress_Initialization, 490 Aspect_Thread_Local_Storage => Name_Thread_Local_Storage, 491 Aspect_Synchronization => Name_Synchronization, 492 Aspect_Test_Case => Name_Test_Case, 493 Aspect_Type_Invariant => Name_Type_Invariant, 494 Aspect_Unchecked_Union => Name_Unchecked_Union, 495 Aspect_Unimplemented => Name_Unimplemented, 496 Aspect_Universal_Aliasing => Name_Universal_Aliasing, 497 Aspect_Universal_Data => Name_Universal_Data, 498 Aspect_Unmodified => Name_Unmodified, 499 Aspect_Unreferenced => Name_Unreferenced, 500 Aspect_Unreferenced_Objects => Name_Unreferenced_Objects, 501 Aspect_Unsuppress => Name_Unsuppress, 502 Aspect_Value_Size => Name_Value_Size, 503 Aspect_Variable_Indexing => Name_Variable_Indexing, 504 Aspect_Volatile => Name_Volatile, 505 Aspect_Volatile_Components => Name_Volatile_Components, 506 Aspect_Warnings => Name_Warnings, 507 Aspect_Write => Name_Write); 508 509 function Get_Aspect_Id (Name : Name_Id) return Aspect_Id; 510 pragma Inline (Get_Aspect_Id); 511 -- Given a name Nam, returns the corresponding aspect id value. If the name 512 -- does not match any aspect, then No_Aspect is returned as the result. 513 514 function Get_Aspect_Id (Aspect : Node_Id) return Aspect_Id; 515 pragma Inline (Get_Aspect_Id); 516 -- Given an aspect specification, return the corresponding aspect_id value. 517 -- If the name does not match any aspect, return No_Aspect. 518 519 ------------------------------------ 520 -- Delaying Evaluation of Aspects -- 521 ------------------------------------ 522 523 -- The RM requires that all language defined aspects taking an expression 524 -- delay evaluation of the expression till the freeze point of the entity 525 -- to which the aspect applies. This allows forward references, and is of 526 -- use for example in connection with preconditions and postconditions 527 -- where the requirement of making all references in contracts to local 528 -- functions be backwards references would be onerous. 529 530 -- For consistency, even attributes like Size are delayed, so we can do: 531 532 -- type A is range 1 .. 10 533 -- with Size => Not_Defined_Yet; 534 -- .. 535 -- Not_Defined_Yet : constant := 64; 536 537 -- Resulting in A having a size of 64, which gets set when A is frozen. 538 -- Furthermore, we can have a situation like 539 540 -- type A is range 1 .. 10 541 -- with Size => Not_Defined_Yet; 542 -- .. 543 -- type B is new A; 544 -- .. 545 -- Not_Defined_Yet : constant := 64; 546 547 -- where the Size of A is considered to have been previously specified at 548 -- the point of derivation, even though the actual value of the size is 549 -- not known yet, and in this example B inherits the size value of 64. 550 551 -- Our normal implementation model (prior to Ada 2012) was simply to copy 552 -- inheritable attributes at the point of derivation. Then any subsequent 553 -- representation items apply either to the parent type, not affecting the 554 -- derived type, or to the derived type, not affecting the parent type. 555 556 -- To deal with the delayed aspect case, we use two flags. The first is 557 -- set on the parent type if it has delayed representation aspects. This 558 -- flag Has_Delayed_Rep_Aspects indicates that if we derive from this type 559 -- we have to worry about making sure we inherit any delayed aspects. The 560 -- second flag is set on a derived type: May_Have_Inherited_Rep_Aspects 561 -- is set if the parent type has Has_Delayed_Rep_Aspects set. 562 563 -- When we freeze a derived type, if the May_Have_Inherited_Rep_Aspects 564 -- flag is set, then we call Freeze.Inherit_Delayed_Rep_Aspects when 565 -- the derived type is frozen, which deals with the necessary copying of 566 -- information from the parent type, which must be frozen at that point 567 -- (since freezing the derived type first freezes the parent type). 568 569 -- SPARK 2014 aspects do not follow the general delay mechanism as they 570 -- act as annotations and cannot modify the attributes of their related 571 -- constructs. To handle forward references in such aspects, the compiler 572 -- delays the analysis of their respective pragmas by collecting them in 573 -- N_Contract nodes. The pragmas are then analyzed at the end of the 574 -- declarative region which contains the related construct. For details, 575 -- see routines Analyze_xxx_In_Decl_Part. 576 577 -- The following shows which aspects are delayed. There are three cases: 578 579 type Delay_Type is 580 (Always_Delay, 581 -- This aspect is not a representation aspect that can be inherited and 582 -- is always delayed, as required by the language definition. 583 584 Never_Delay, 585 -- There are two cases. There are language defined aspects like 586 -- Convention where the "expression" is simply an uninterpreted 587 -- identifier, and there is no issue of evaluating it and thus no 588 -- issue of delaying the evaluation. The second case is implementation 589 -- defined aspects where we have decided that we don't want to allow 590 -- delays (and for our own aspects we can do what we like). 591 592 Rep_Aspect); 593 -- These are the cases of representation aspects that are in general 594 -- delayed, and where there is a potential issue of derived types that 595 -- inherit delayed representation values. 596 597 -- Note: even if this table indicates that an aspect is delayed, we never 598 -- delay Boolean aspects that have a missing expression (taken as True), 599 -- or expressions for delayed rep items that consist of an integer literal 600 -- (most cases of Size etc. in practice), since in these cases we know we 601 -- can get the value of the expression without delay. Note that we still 602 -- need to delay Boolean aspects that are specifically set to True: 603 604 -- type R is array (0 .. 31) of Boolean 605 -- with Pack => True; 606 -- True : constant Boolean := False; 607 608 -- This is nonsense, but we need to make it work and result in R not 609 -- being packed, and if we have something like: 610 611 -- type R is array (0 .. 31) of Boolean 612 -- with Pack => True; 613 -- RR : R; 614 -- True : constant Boolean := False; 615 616 -- This is illegal because the visibility of True changes after the freeze 617 -- point, which is not allowed, and we need the delay mechanism to properly 618 -- diagnose this error. 619 620 Aspect_Delay : constant array (Aspect_Id) of Delay_Type := 621 (No_Aspect => Always_Delay, 622 Aspect_Address => Always_Delay, 623 Aspect_All_Calls_Remote => Always_Delay, 624 Aspect_Asynchronous => Always_Delay, 625 Aspect_Attach_Handler => Always_Delay, 626 Aspect_Constant_Indexing => Always_Delay, 627 Aspect_CPU => Always_Delay, 628 Aspect_Default_Iterator => Always_Delay, 629 Aspect_Default_Storage_Pool => Always_Delay, 630 Aspect_Default_Value => Always_Delay, 631 Aspect_Default_Component_Value => Always_Delay, 632 Aspect_Discard_Names => Always_Delay, 633 Aspect_Dispatching_Domain => Always_Delay, 634 Aspect_Dynamic_Predicate => Always_Delay, 635 Aspect_Elaborate_Body => Always_Delay, 636 Aspect_Export => Always_Delay, 637 Aspect_External_Name => Always_Delay, 638 Aspect_External_Tag => Always_Delay, 639 Aspect_Favor_Top_Level => Always_Delay, 640 Aspect_Implicit_Dereference => Always_Delay, 641 Aspect_Import => Always_Delay, 642 Aspect_Independent => Always_Delay, 643 Aspect_Independent_Components => Always_Delay, 644 Aspect_Inline => Always_Delay, 645 Aspect_Inline_Always => Always_Delay, 646 Aspect_Input => Always_Delay, 647 Aspect_Interrupt_Handler => Always_Delay, 648 Aspect_Interrupt_Priority => Always_Delay, 649 Aspect_Invariant => Always_Delay, 650 Aspect_Iterable => Always_Delay, 651 Aspect_Iterator_Element => Always_Delay, 652 Aspect_Link_Name => Always_Delay, 653 Aspect_Linker_Section => Always_Delay, 654 Aspect_Lock_Free => Always_Delay, 655 Aspect_No_Return => Always_Delay, 656 Aspect_Output => Always_Delay, 657 Aspect_Persistent_BSS => Always_Delay, 658 Aspect_Post => Always_Delay, 659 Aspect_Postcondition => Always_Delay, 660 Aspect_Pre => Always_Delay, 661 Aspect_Precondition => Always_Delay, 662 Aspect_Predicate => Always_Delay, 663 Aspect_Preelaborable_Initialization => Always_Delay, 664 Aspect_Preelaborate => Always_Delay, 665 Aspect_Priority => Always_Delay, 666 Aspect_Pure => Always_Delay, 667 Aspect_Pure_Function => Always_Delay, 668 Aspect_Read => Always_Delay, 669 Aspect_Relative_Deadline => Always_Delay, 670 Aspect_Remote_Access_Type => Always_Delay, 671 Aspect_Remote_Call_Interface => Always_Delay, 672 Aspect_Remote_Types => Always_Delay, 673 Aspect_Shared => Always_Delay, 674 Aspect_Shared_Passive => Always_Delay, 675 Aspect_Simple_Storage_Pool => Always_Delay, 676 Aspect_Simple_Storage_Pool_Type => Always_Delay, 677 Aspect_Static_Predicate => Always_Delay, 678 Aspect_Storage_Pool => Always_Delay, 679 Aspect_Stream_Size => Always_Delay, 680 Aspect_Suppress => Always_Delay, 681 Aspect_Suppress_Debug_Info => Always_Delay, 682 Aspect_Suppress_Initialization => Always_Delay, 683 Aspect_Thread_Local_Storage => Always_Delay, 684 Aspect_Type_Invariant => Always_Delay, 685 Aspect_Unchecked_Union => Always_Delay, 686 Aspect_Universal_Aliasing => Always_Delay, 687 Aspect_Universal_Data => Always_Delay, 688 Aspect_Unmodified => Always_Delay, 689 Aspect_Unreferenced => Always_Delay, 690 Aspect_Unreferenced_Objects => Always_Delay, 691 Aspect_Unsuppress => Always_Delay, 692 Aspect_Variable_Indexing => Always_Delay, 693 Aspect_Write => Always_Delay, 694 695 Aspect_Abstract_State => Never_Delay, 696 Aspect_Annotate => Never_Delay, 697 Aspect_Async_Readers => Never_Delay, 698 Aspect_Async_Writers => Never_Delay, 699 Aspect_Contract_Cases => Never_Delay, 700 Aspect_Convention => Never_Delay, 701 Aspect_Default_Initial_Condition => Never_Delay, 702 Aspect_Depends => Never_Delay, 703 Aspect_Dimension => Never_Delay, 704 Aspect_Dimension_System => Never_Delay, 705 Aspect_Effective_Reads => Never_Delay, 706 Aspect_Effective_Writes => Never_Delay, 707 Aspect_Extensions_Visible => Never_Delay, 708 Aspect_Ghost => Never_Delay, 709 Aspect_Global => Never_Delay, 710 Aspect_Initial_Condition => Never_Delay, 711 Aspect_Initializes => Never_Delay, 712 Aspect_No_Elaboration_Code_All => Never_Delay, 713 Aspect_No_Tagged_Streams => Never_Delay, 714 Aspect_Obsolescent => Never_Delay, 715 Aspect_Part_Of => Never_Delay, 716 Aspect_Refined_Depends => Never_Delay, 717 Aspect_Refined_Global => Never_Delay, 718 Aspect_Refined_Post => Never_Delay, 719 Aspect_Refined_State => Never_Delay, 720 Aspect_SPARK_Mode => Never_Delay, 721 Aspect_Synchronization => Never_Delay, 722 Aspect_Test_Case => Never_Delay, 723 Aspect_Unimplemented => Never_Delay, 724 Aspect_Warnings => Never_Delay, 725 726 Aspect_Alignment => Rep_Aspect, 727 Aspect_Atomic => Rep_Aspect, 728 Aspect_Atomic_Components => Rep_Aspect, 729 Aspect_Bit_Order => Rep_Aspect, 730 Aspect_Component_Size => Rep_Aspect, 731 Aspect_Machine_Radix => Rep_Aspect, 732 Aspect_Object_Size => Rep_Aspect, 733 Aspect_Pack => Rep_Aspect, 734 Aspect_Scalar_Storage_Order => Rep_Aspect, 735 Aspect_Size => Rep_Aspect, 736 Aspect_Small => Rep_Aspect, 737 Aspect_Storage_Size => Rep_Aspect, 738 Aspect_Value_Size => Rep_Aspect, 739 Aspect_Volatile => Rep_Aspect, 740 Aspect_Volatile_Components => Rep_Aspect); 741 742 ------------------------------------------------ 743 -- Handling of Aspect Specifications on Stubs -- 744 ------------------------------------------------ 745 746 -- Aspects that appear on the following stub nodes 747 748 -- N_Package_Body_Stub 749 -- N_Protected_Body_Stub 750 -- N_Subprogram_Body_Stub 751 -- N_Task_Body_Stub 752 753 -- are treated as if they apply to the corresponding proper body. Their 754 -- analysis is postponed until the analysis of the proper body takes place 755 -- (see Analyze_Proper_Body). The delay is required because the analysis 756 -- may generate extra code which would be harder to relocate to the body. 757 -- If the proper body is present, the aspect specifications are relocated 758 -- to the corresponding body node: 759 760 -- N_Package_Body 761 -- N_Protected_Body 762 -- N_Subprogram_Body 763 -- N_Task_Body 764 765 -- The subsequent analysis takes care of the aspect-to-pragma conversions 766 -- and verification of pragma legality. In the case where the proper body 767 -- is not available, the aspect specifications are analyzed on the spot 768 -- (see Analyze_Proper_Body) to catch potential errors. 769 770 -- The following table lists all aspects that can apply to a subprogram 771 -- body [stub]. For instance, the following example is legal: 772 773 -- package P with SPARK_Mode ...; 774 -- package body P with SPARK_Mode is ...; 775 776 -- The table should be synchronized with Pragma_On_Body_Or_Stub_OK in unit 777 -- Sem_Prag if the aspects below are implemented by a pragma. 778 779 Aspect_On_Body_Or_Stub_OK : constant array (Aspect_Id) of Boolean := 780 (Aspect_Refined_Depends => True, 781 Aspect_Refined_Global => True, 782 Aspect_Refined_Post => True, 783 Aspect_SPARK_Mode => True, 784 Aspect_Warnings => True, 785 others => False); 786 787 --------------------------------------------------- 788 -- Handling of Aspect Specifications in the Tree -- 789 --------------------------------------------------- 790 791 -- Several kinds of declaration node permit aspect specifications in Ada 792 -- 2012 mode. If there was room in all the corresponding declaration nodes, 793 -- we could just have a field Aspect_Specifications pointing to a list of 794 -- nodes for the aspects (N_Aspect_Specification nodes). But there isn't 795 -- room, so we adopt a different approach. 796 797 -- The following subprograms provide access to a specialized interface 798 -- implemented internally with a hash table in the body, that provides 799 -- access to aspect specifications. 800 801 function Aspect_Specifications (N : Node_Id) return List_Id; 802 -- Given a node N, returns the list of N_Aspect_Specification nodes that 803 -- are attached to this declaration node. If the node is in the class of 804 -- declaration nodes that permit aspect specifications, as defined by the 805 -- predicate above, and if their Has_Aspects flag is set to True, then this 806 -- will always be a non-empty list. If this flag is set to False, then 807 -- No_List is returned. Normally, the only nodes that have Has_Aspects set 808 -- True are the nodes for which Permits_Aspect_Specifications would return 809 -- True (i.e. the declaration nodes defined in the RM as permitting the 810 -- presence of Aspect_Specifications). However, it is possible for the 811 -- flag Has_Aspects to be set on other nodes as a result of Rewrite and 812 -- Replace calls, and this function may be used to retrieve the aspect 813 -- specifications for the original rewritten node in such cases. 814 815 function Aspects_On_Body_Or_Stub_OK (N : Node_Id) return Boolean; 816 -- N denotes a body [stub] with aspects. Determine whether all aspects of N 817 -- are allowed to appear on a body [stub]. 818 819 procedure Exchange_Aspects (N1 : Node_Id; N2 : Node_Id); 820 -- Exchange the aspect specifications of two nodes. If either node lacks an 821 -- aspect specification list, the routine has no effect. It is assumed that 822 -- both nodes can support aspects. 823 824 function Find_Aspect (Id : Entity_Id; A : Aspect_Id) return Node_Id; 825 -- Find the aspect specification of aspect A associated with entity I. 826 -- Return Empty if Id does not have the requested aspect. 827 828 function Find_Value_Of_Aspect 829 (Id : Entity_Id; 830 A : Aspect_Id) return Node_Id; 831 -- Find the value of aspect A associated with entity Id. Return Empty if 832 -- Id does not have the requested aspect. 833 834 function Has_Aspect (Id : Entity_Id; A : Aspect_Id) return Boolean; 835 -- Determine whether entity Id has aspect A 836 837 procedure Move_Aspects (From : Node_Id; To : Node_Id); 838 -- Relocate the aspect specifications of node From to node To. On entry it 839 -- is assumed that To does not have aspect specifications. If From has no 840 -- aspects, the routine has no effect. 841 842 procedure Move_Or_Merge_Aspects (From : Node_Id; To : Node_Id); 843 -- Relocate the aspect specifications of node From to node To. If To has 844 -- aspects, the aspects of From are added to the aspects of To. If From has 845 -- no aspects, the routine has no effect. When From denotes a subprogram 846 -- body stub that also acts as a spec, the only aspects relocated to node 847 -- To are those from table Aspect_On_Body_Or_Stub_OK and preconditions. 848 849 function Permits_Aspect_Specifications (N : Node_Id) return Boolean; 850 -- Returns True if the node N is a declaration node that permits aspect 851 -- specifications in the grammar. It is possible for other nodes to have 852 -- aspect specifications as a result of Rewrite or Replace calls. 853 854 procedure Remove_Aspects (N : Node_Id); 855 -- Delete the aspect specifications associated with node N. If the node has 856 -- no aspects, the routine has no effect. 857 858 function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean; 859 -- Returns True if A1 and A2 are (essentially) the same aspect. This is not 860 -- a simple equality test because e.g. Post and Postcondition are the same. 861 -- This is used for detecting duplicate aspects. 862 863 procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id); 864 -- The node N must be in the class of declaration nodes that permit aspect 865 -- specifications and the Has_Aspects flag must be False on entry. L must 866 -- be a non-empty list of N_Aspect_Specification nodes. This procedure sets 867 -- the Has_Aspects flag to True, and makes an entry that can be retrieved 868 -- by a subsequent Aspect_Specifications call. It is an error to call this 869 -- procedure with a node that does not permit aspect specifications, or a 870 -- node that has its Has_Aspects flag set True on entry, or with L being an 871 -- empty list or No_List. 872 873 procedure Tree_Read; 874 -- Reads contents of Aspect_Specifications hash table from the tree file 875 876 procedure Tree_Write; 877 -- Writes contents of Aspect_Specifications hash table to the tree file 878 879end Aspects; 880