1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2020, Free Software Foundation, Inc. --
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. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 -- Pragma handling is isolated in a separate package
27 -- (logically this processing belongs in chapter 4)
29 with Namet; use Namet;
31 with Snames; use Snames;
32 with Types; use Types;
36 -- The following table lists all pragmas that emulate an Ada 2012 aspect
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,
52 Pragma_CUDA_Global => True,
53 Pragma_Default_Initial_Condition => True,
54 Pragma_Default_Storage_Pool => True,
55 Pragma_Depends => True,
56 Pragma_Discard_Names => True,
57 Pragma_Dispatching_Domain => True,
58 Pragma_Effective_Reads => True,
59 Pragma_Effective_Writes => True,
60 Pragma_Elaborate_Body => True,
61 Pragma_Export => True,
62 Pragma_Extensions_Visible => True,
63 Pragma_Favor_Top_Level => True,
65 Pragma_Global => True,
66 Pragma_Import => True,
67 Pragma_Independent => True,
68 Pragma_Independent_Components => True,
69 Pragma_Initial_Condition => True,
70 Pragma_Initializes => True,
71 Pragma_Inline => True,
72 Pragma_Inline_Always => True,
73 Pragma_Interrupt_Handler => True,
74 Pragma_Interrupt_Priority => True,
75 Pragma_Invariant => True,
76 Pragma_Linker_Section => True,
77 Pragma_Lock_Free => True,
78 Pragma_No_Elaboration_Code_All => True,
79 Pragma_No_Return => True,
80 Pragma_Obsolescent => True,
82 Pragma_Part_Of => True,
83 Pragma_Persistent_BSS => True,
85 Pragma_Post_Class => True,
86 Pragma_Postcondition => True,
88 Pragma_Pre_Class => True,
89 Pragma_Precondition => True,
90 Pragma_Predicate => True,
91 Pragma_Preelaborable_Initialization => True,
92 Pragma_Preelaborate => True,
93 Pragma_Priority => True,
95 Pragma_Pure_Function => True,
96 Pragma_Refined_Depends => True,
97 Pragma_Refined_Global => True,
98 Pragma_Refined_Post => True,
99 Pragma_Refined_State => True,
100 Pragma_Relative_Deadline => True,
101 Pragma_Remote_Access_Type => True,
102 Pragma_Remote_Call_Interface => True,
103 Pragma_Remote_Types => True,
104 Pragma_Secondary_Stack_Size => True,
105 Pragma_Shared => True,
106 Pragma_Shared_Passive => True,
107 Pragma_Simple_Storage_Pool_Type => True,
108 Pragma_SPARK_Mode => True,
109 Pragma_Storage_Size => True,
110 Pragma_Suppress => True,
111 Pragma_Suppress_Debug_Info => True,
112 Pragma_Suppress_Initialization => True,
113 Pragma_Test_Case => True,
114 Pragma_Thread_Local_Storage => True,
115 Pragma_Type_Invariant => True,
116 Pragma_Unchecked_Union => True,
117 Pragma_Universal_Aliasing => True,
118 Pragma_Universal_Data => True,
119 Pragma_Unmodified => True,
120 Pragma_Unreferenced => True,
121 Pragma_Unreferenced_Objects => True,
122 Pragma_Unsuppress => True,
123 Pragma_Volatile => True,
124 Pragma_Volatile_Components => True,
125 Pragma_Volatile_Full_Access => True,
126 Pragma_Warnings => True,
129 -- The following table lists all pragmas that act as an assertion
132 Assertion_Expression_Pragma : constant array (Pragma_Id) of Boolean :=
133 (Pragma_Assert => True,
134 Pragma_Assert_And_Cut => True,
135 Pragma_Assume => True,
136 Pragma_Check => True,
137 Pragma_Contract_Cases => True,
138 Pragma_Default_Initial_Condition => True,
139 Pragma_Initial_Condition => True,
140 Pragma_Invariant => True,
141 Pragma_Loop_Invariant => True,
142 Pragma_Loop_Variant => True,
144 Pragma_Post_Class => True,
145 Pragma_Postcondition => True,
147 Pragma_Pre_Class => True,
148 Pragma_Precondition => True,
149 Pragma_Predicate => True,
150 Pragma_Refined_Post => True,
151 Pragma_Test_Case => True,
152 Pragma_Type_Invariant => True,
153 Pragma_Type_Invariant_Class => True,
156 -- The following table lists all the implementation-defined pragmas that
157 -- should apply to the anonymous object produced by the analysis of a
158 -- single protected or task type. The table should be synchronized with
159 -- Aspect_On_Anonymous_Object_OK in unit Aspects.
161 Pragma_On_Anonymous_Object_OK : constant array (Pragma_Id) of Boolean :=
162 (Pragma_Depends => True,
163 Pragma_Global => True,
164 Pragma_Part_Of => True,
167 -- The following table lists all the implementation-defined pragmas that
168 -- may apply to a body stub (no language defined pragmas apply). The table
169 -- should be synchronized with Aspect_On_Body_Or_Stub_OK in unit Aspects.
171 Pragma_On_Body_Or_Stub_OK : constant array (Pragma_Id) of Boolean :=
172 (Pragma_Refined_Depends => True,
173 Pragma_Refined_Global => True,
174 Pragma_Refined_Post => True,
175 Pragma_SPARK_Mode => True,
176 Pragma_Warnings => True,
179 -- The following table lists all pragmas which are significant in SPARK and
180 -- as a result get translated into verification conditions. The table is an
181 -- amalgamation of the pragmas listed in SPARK RM 16.1 and internally added
184 Pragma_Significant_In_SPARK : constant array (Pragma_Id) of Boolean :=
185 (Pragma_All_Calls_Remote => False,
186 Pragma_Asynchronous => False,
187 Pragma_Default_Storage_Pool => False,
188 Pragma_Discard_Names => False,
189 Pragma_Dispatching_Domain => False,
190 Pragma_Priority_Specific_Dispatching => False,
191 Pragma_Remote_Call_Interface => False,
192 Pragma_Remote_Types => False,
193 Pragma_Shared_Passive => False,
194 Pragma_Task_Dispatching_Policy => False,
195 Pragma_Unmodified => False,
196 Pragma_Unreferenced => False,
197 Pragma_Warnings => False,
204 procedure Analyze_Pragma (N : Node_Id);
205 -- Analyze procedure for pragma reference node N
207 procedure Analyze_Contract_Cases_In_Decl_Part
209 Freeze_Id : Entity_Id := Empty);
210 -- Perform full analysis of delayed pragma Contract_Cases. Freeze_Id is the
211 -- entity of [generic] package body or [generic] subprogram body which
212 -- caused "freezing" of the related contract where the pragma resides.
214 procedure Analyze_Depends_In_Decl_Part (N : Node_Id);
215 -- Perform full analysis of delayed pragma Depends. This routine is also
216 -- capable of performing basic analysis of pragma Refined_Depends.
218 procedure Analyze_External_Property_In_Decl_Part
220 Expr_Val : out Boolean);
221 -- Perform full analysis of delayed pragmas Async_Readers, Async_Writers,
222 -- Effective_Reads, Effective_Writes and No_Caching. Flag Expr_Val contains
223 -- the Boolean argument of the pragma or a default True if no argument
226 procedure Analyze_Global_In_Decl_Part (N : Node_Id);
227 -- Perform full analysis of delayed pragma Global. This routine is also
228 -- capable of performing basic analysis of pragma Refined_Global.
230 procedure Analyze_Initial_Condition_In_Decl_Part (N : Node_Id);
231 -- Perform full analysis of delayed pragma Initial_Condition
233 procedure Analyze_Initializes_In_Decl_Part (N : Node_Id);
234 -- Perform full analysis of delayed pragma Initializes
236 procedure Analyze_Part_Of_In_Decl_Part
238 Freeze_Id : Entity_Id := Empty);
239 -- Perform full analysis of delayed pragma Part_Of. Freeze_Id is the entity
240 -- of [generic] package body or [generic] subprogram body which caused the
241 -- "freezing" of the related contract where the pragma resides.
243 procedure Analyze_Pre_Post_Condition_In_Decl_Part
245 Freeze_Id : Entity_Id := Empty);
246 -- Perform full analysis of pragmas Precondition and Postcondition.
247 -- Freeze_Id denotes the entity of [generic] package body or [generic]
248 -- subprogram body which caused "freezing" of the related contract where
249 -- the pragma resides.
251 procedure Analyze_Refined_Depends_In_Decl_Part (N : Node_Id);
252 -- Preform full analysis of delayed pragma Refined_Depends. This routine
253 -- uses Analyze_Depends_In_Decl_Part as a starting point, then performs
254 -- various consistency checks between Depends and Refined_Depends.
256 procedure Analyze_Refined_Global_In_Decl_Part (N : Node_Id);
257 -- Perform full analysis of delayed pragma Refined_Global. This routine
258 -- uses Analyze_Global_In_Decl_Part as a starting point, then performs
259 -- various consistency checks between Global and Refined_Global.
261 procedure Analyze_Refined_State_In_Decl_Part
263 Freeze_Id : Entity_Id := Empty);
264 -- Perform full analysis of delayed pragma Refined_State. Freeze_Id denotes
265 -- the entity of [generic] package body or [generic] subprogram body which
266 -- caused "freezing" of the related contract where the pragma resides.
268 procedure Analyze_Subprogram_Variant_In_Decl_Part
270 Freeze_Id : Entity_Id := Empty);
271 -- Perform full analysis of delayed pragma Subprogram_Variant. Freeze_Id is
272 -- the entity of [generic] package body or [generic] subprogram body which
273 -- caused "freezing" of the related contract where the pragma resides.
275 procedure Analyze_Test_Case_In_Decl_Part (N : Node_Id);
276 -- Perform preanalysis of pragma Test_Case
278 function Build_Pragma_Check_Equivalent
280 Subp_Id : Entity_Id := Empty;
281 Inher_Id : Entity_Id := Empty;
282 Keep_Pragma_Id : Boolean := False) return Node_Id;
283 -- Transform a pre- or [refined] postcondition denoted by Prag into an
284 -- equivalent pragma Check. When the pre- or postcondition is inherited,
285 -- the routine replaces the references of all formals of Inher_Id
286 -- and primitive operations of its controlling type by references
287 -- to the corresponding entities of Subp_Id and the descendant type.
288 -- Keep_Pragma_Id is True when the newly created pragma should be
289 -- in fact of the same kind as the source pragma Prag. This is used
290 -- in GNATprove_Mode to generate the inherited pre- and postconditions.
292 procedure Check_Applicable_Policy (N : Node_Id);
293 -- N is either an N_Aspect or an N_Pragma node. There are two cases. If
294 -- the name of the aspect or pragma is not one of those recognized as
295 -- an assertion kind by an Assertion_Policy pragma, then the call has
296 -- no effect. Note that in the case of a pragma derived from an aspect,
297 -- the name we use for the purpose of this procedure is the aspect name,
298 -- which may be different from the pragma name (e.g. Precondition for
299 -- Pre aspect). In addition, 'Class aspects are recognized (and the
300 -- corresponding special names used in the processing).
302 -- If the name is a valid assertion kind name, then the Check_Policy pragma
303 -- chain is checked for a matching entry (or for an Assertion entry which
304 -- matches all possibilities). If a matching entry is found then the policy
305 -- is checked. If it is On or Check, then the Is_Checked flag is set in
306 -- the aspect or pragma node. If it is Off, Ignore, or Disable, then the
307 -- Is_Ignored flag is set in the aspect or pragma node. Additionally for
308 -- policy Disable, the Is_Disabled flag is set.
310 -- If no matching Check_Policy pragma is found then the effect depends on
311 -- whether -gnata was used, if so, then the call has no effect, otherwise
312 -- Is_Ignored (but not Is_Disabled) is set True.
314 procedure Check_External_Properties
320 -- Flags AR, AW, ER and EW denote the static values of external properties
321 -- Async_Readers, Async_Writers, Effective_Reads and Effective_Writes. Item
322 -- is the related variable or state. Ensure legality of the combination and
323 -- issue an error for an illegal combination.
325 function Check_Kind (Nam : Name_Id) return Name_Id;
326 -- This function is used in connection with pragmas Assert, Check,
327 -- and assertion aspects and pragmas, to determine if Check pragmas
328 -- (or corresponding assertion aspects or pragmas) are currently active
329 -- as determined by the presence of -gnata on the command line (which
330 -- sets the default), and the appearance of pragmas Check_Policy and
331 -- Assertion_Policy as configuration pragmas either in a configuration
332 -- pragma file, or at the start of the current unit, or locally given
333 -- Check_Policy and Assertion_Policy pragmas that are currently active.
335 -- The value returned is one of the names Check, Ignore, Disable (On
336 -- returns Check, and Off returns Ignore).
338 -- Note: for assertion kinds Pre'Class, Post'Class, Invariant'Class,
339 -- and Type_Invariant'Class, the name passed is Name_uPre, Name_uPost,
340 -- Name_uInvariant, or Name_uType_Invariant, which corresponds to _Pre,
341 -- _Post, _Invariant, or _Type_Invariant, which are special names used
342 -- in identifiers to represent these attribute references.
344 procedure Check_Missing_Part_Of (Item_Id : Entity_Id);
345 -- Determine whether the placement within the state space of an abstract
346 -- state, variable or package instantiation denoted by Item_Id requires the
347 -- use of indicator/option Part_Of. If this is the case, emit an error.
349 procedure Collect_Inherited_Class_Wide_Conditions (Subp : Entity_Id);
350 -- In GNATprove mode, when analyzing an overriding subprogram, check
351 -- whether the overridden operations have class-wide pre/postconditions,
352 -- and generate the corresponding pragmas. The pragmas are inserted after
353 -- the subprogram declaration, together with those generated for other
354 -- aspects of the subprogram.
356 procedure Collect_Subprogram_Inputs_Outputs
357 (Subp_Id : Entity_Id;
358 Synthesize : Boolean := False;
359 Subp_Inputs : in out Elist_Id;
360 Subp_Outputs : in out Elist_Id;
361 Global_Seen : out Boolean);
362 -- Subsidiary to the analysis of pragmas Depends, Global, Refined_Depends
363 -- and Refined_Global. The routine is also used by GNATprove. Collect all
364 -- inputs and outputs of subprogram Subp_Id in lists Subp_Inputs (inputs)
365 -- and Subp_Outputs (outputs). The inputs and outputs are gathered from:
366 -- 1) The formal parameters of the subprogram
367 -- 2) The generic formal parameters of the generic subprogram
368 -- 3) The current instance of a concurrent type
369 -- 4) The items of pragma [Refined_]Global
371 -- 5) The items of pragma [Refined_]Depends if there is no pragma
372 -- [Refined_]Global present and flag Synthesize is set to True.
373 -- If the subprogram has no inputs and/or outputs, then the returned list
374 -- is No_Elist. Flag Global_Seen is set when the related subprogram has
375 -- pragma [Refined_]Global.
377 function Delay_Config_Pragma_Analyze (N : Node_Id) return Boolean;
378 -- N is a pragma appearing in a configuration pragma file. Most such
379 -- pragmas are analyzed when the file is read, before parsing and analyzing
380 -- the main unit. However, the analysis of certain pragmas results in
381 -- adding information to the compiled main unit, and this cannot be done
382 -- till the main unit is processed. Such pragmas return True from this
383 -- function and in Frontend pragmas where Delay_Config_Pragma_Analyze is
384 -- True have their analysis delayed until after the main program is parsed
387 function Find_Related_Package_Or_Body
389 Do_Checks : Boolean := False) return Node_Id;
390 -- Subsidiary to the analysis of pragmas
395 -- Find the declaration of the related package [body] subject to pragma
396 -- Prag. The return value is either N_Package_Declaration, N_Package_Body,
397 -- or Empty if the placement of the pragma is illegal. If flag Do_Checks is
398 -- set, the routine reports duplicate pragmas.
400 function Find_Related_Declaration_Or_Body
402 Do_Checks : Boolean := False) return Node_Id;
403 -- Subsidiary to the analysis of pragmas
406 -- Extensions_Visible
409 -- Max_Entry_Queue_Depth
410 -- Max_Entry_Queue_Length
424 -- as well as attributes 'Old and 'Result. Find the declaration of the
425 -- related entry, subprogram or task type [body] subject to pragma Prag.
426 -- If flag Do_Checks is set, the routine reports duplicate pragmas and
427 -- detects improper use of refinement pragmas in stand alone expression
430 function Get_Argument
432 Context_Id : Node_Id := Empty) return Node_Id;
433 -- Obtain the argument of pragma Prag depending on context and the nature
434 -- of the pragma. The argument is extracted in the following manner:
436 -- When the pragma is generated from an aspect, return the corresponding
437 -- aspect when Context_Id denotes a generic unit.
439 -- Otherwise return the first argument of Prag
441 -- Context denotes the entity of the function, package or procedure where
444 function Get_SPARK_Mode_From_Annotation
445 (N : Node_Id) return SPARK_Mode_Type;
446 -- Given an aspect or pragma SPARK_Mode node, return corresponding mode id
448 procedure Initialize;
449 -- Initializes data structures used for pragma processing. Must be called
450 -- before analyzing each new main source program.
452 function Is_Config_Static_String (Arg : Node_Id) return Boolean;
453 -- This is called for a configuration pragma that requires either string
454 -- literal or a concatenation of string literals. We cannot use normal
455 -- static string processing because it is too early in the case of the
456 -- pragma appearing in a configuration pragmas file. If Arg is of an
457 -- appropriate form, then this call obtains the string (doing any necessary
458 -- concatenations) and places it in Name_Buffer, setting Name_Len to its
459 -- length, and then returns True. If it is not of the correct form, then an
460 -- appropriate error message is posted, and False is returned.
462 function Is_Elaboration_SPARK_Mode (N : Node_Id) return Boolean;
463 -- Determine whether pragma SPARK_Mode appears in the statement part of a
466 function Is_Enabled_Pragma (Prag : Node_Id) return Boolean;
467 -- Determine whether a Boolean-like SPARK pragma Prag is enabled. To be
468 -- considered enabled, the pragma must either:
469 -- * Appear without its Boolean expression
470 -- * The Boolean expression evaluates to "True"
472 -- Boolean-like SPARK pragmas differ from pure Boolean Ada pragmas in that
473 -- their optional Boolean expression must be static and cannot benefit from
474 -- forward references. The following are Boolean-like SPARK pragmas:
477 -- Constant_After_Elaboration
480 -- Extensions_Visible
483 function Is_Non_Significant_Pragma_Reference (N : Node_Id) return Boolean;
484 -- The node N is a node for an entity and the issue is whether the
485 -- occurrence is a reference for the purposes of giving warnings about
486 -- unreferenced variables. This function returns True if the reference is
487 -- not a reference from this point of view (e.g. the occurrence in a pragma
488 -- Pack) and False if it is a real reference (e.g. the occurrence in a
491 function Is_Pragma_String_Literal (Par : Node_Id) return Boolean;
492 -- Given an N_Pragma_Argument_Association node, Par, which has the form of
493 -- an operator symbol, determines whether or not it should be treated as an
494 -- string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol. If
495 -- True is returned, the argument is converted to a string literal. If
496 -- False is returned, then the argument is treated as an entity reference
499 function Is_Private_SPARK_Mode (N : Node_Id) return Boolean;
500 -- Determine whether pragma SPARK_Mode appears in the private part of a
503 function Is_Valid_Assertion_Kind (Nam : Name_Id) return Boolean;
504 -- Returns True if Nam is one of the names recognized as a valid assertion
505 -- kind by the Assertion_Policy pragma. Note that the 'Class cases are
506 -- represented by the corresponding special names Name_uPre, Name_uPost,
507 -- Name_uInvariant, and Name_uType_Invariant (_Pre, _Post, _Invariant,
508 -- and _Type_Invariant).
510 procedure Process_Compilation_Unit_Pragmas (N : Node_Id);
511 -- Called at the start of processing compilation unit N to deal with any
512 -- special issues regarding pragmas. In particular, we have to deal with
513 -- Suppress_All at this stage, since it can appear after the unit instead
514 -- of before (actually we allow it to appear anywhere).
516 procedure Relocate_Pragmas_To_Anonymous_Object
519 -- Relocate all pragmas that appear in the visible declarations of task or
520 -- protected type declaration Typ_Decl after the declaration of anonymous
521 -- object Obj_Decl. Table Pragmas_On_Anonymous_Object_OK contains the list
522 -- of candidate pragmas.
524 procedure Relocate_Pragmas_To_Body
525 (Subp_Body : Node_Id;
526 Target_Body : Node_Id := Empty);
527 -- Resocate all pragmas that follow and apply to subprogram body Subp_Body
528 -- to its own declaration list. Candidate pragmas are classified in table
529 -- Pragma_On_Body_Or_Stub_OK. If Target_Body is set, the pragma are moved
530 -- to the declarations of Target_Body. This formal should be set when
531 -- dealing with subprogram body stubs or expression functions.
533 procedure Set_Encoded_Interface_Name (E : Entity_Id; S : Node_Id);
534 -- This routine is used to set an encoded interface name. The node S is
535 -- an N_String_Literal node for the external name to be set, and E is an
536 -- entity whose Interface_Name field is to be set. In the normal case where
537 -- S contains a name that is a valid C identifier, then S is simply set as
538 -- the value of the Interface_Name. Otherwise it is encoded as needed by
539 -- particular operating systems. See the body for details of the encoding.
541 procedure Set_Overflow_Mode (N : Node_Id);
542 -- Sets Sem.Scope_Suppress according to the overflow modes specified in
543 -- the pragma Overflow_Mode passed in argument. This should only be called
544 -- after N has been successfully analyzed.
546 function Test_Case_Arg
549 From_Aspect : Boolean := False) return Node_Id;
550 -- Obtain argument "Name", "Mode", "Ensures" or "Requires" from Test_Case
551 -- pragma Prag as denoted by Arg_Nam. When From_Aspect is set, an attempt
552 -- is made to retrieve the argument from the corresponding aspect if there
553 -- is one. The returned argument has several formats:
555 -- N_Pragma_Argument_Association if retrieved directly from the pragma
557 -- N_Component_Association if retrieved from the corresponding aspect and
558 -- the argument appears in a named association form.
560 -- An arbitrary expression if retrieved from the corresponding aspect and
561 -- the argument appears in positional form.
563 -- Empty if there is no such argument
565 procedure Validate_Compile_Time_Warning_Errors;
566 -- This routine is called after calling the back end to validate pragmas
567 -- Compile_Time_Error and Compile_Time_Warning for size and alignment
568 -- appropriateness. The reason it is called that late is to take advantage
569 -- of any back-annotation of size and alignment performed by the back end.
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