1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2017, 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_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,
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,
81 Pragma_Part_Of
=> True,
82 Pragma_Persistent_BSS
=> True,
84 Pragma_Post_Class
=> True,
85 Pragma_Postcondition
=> 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,
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_Secondary_Stack_Size
=> True,
104 Pragma_Shared
=> True,
105 Pragma_Shared_Passive
=> True,
106 Pragma_Simple_Storage_Pool_Type
=> True,
107 Pragma_SPARK_Mode
=> True,
108 Pragma_Storage_Size
=> True,
109 Pragma_Suppress
=> True,
110 Pragma_Suppress_Debug_Info
=> True,
111 Pragma_Suppress_Initialization
=> True,
112 Pragma_Test_Case
=> True,
113 Pragma_Thread_Local_Storage
=> True,
114 Pragma_Type_Invariant
=> True,
115 Pragma_Unchecked_Union
=> True,
116 Pragma_Universal_Aliasing
=> True,
117 Pragma_Universal_Data
=> True,
118 Pragma_Unmodified
=> True,
119 Pragma_Unreferenced
=> True,
120 Pragma_Unreferenced_Objects
=> True,
121 Pragma_Unsuppress
=> True,
122 Pragma_Volatile
=> True,
123 Pragma_Volatile_Components
=> True,
124 Pragma_Volatile_Full_Access
=> True,
125 Pragma_Warnings
=> True,
128 -- The following table lists all pragmas that act as an assertion
131 Assertion_Expression_Pragma
: constant array (Pragma_Id
) of Boolean :=
132 (Pragma_Assert
=> True,
133 Pragma_Assert_And_Cut
=> True,
134 Pragma_Assume
=> True,
135 Pragma_Check
=> True,
136 Pragma_Contract_Cases
=> True,
137 Pragma_Default_Initial_Condition
=> True,
138 Pragma_Initial_Condition
=> True,
139 Pragma_Invariant
=> True,
140 Pragma_Loop_Invariant
=> True,
141 Pragma_Loop_Variant
=> True,
143 Pragma_Post_Class
=> True,
144 Pragma_Postcondition
=> True,
146 Pragma_Pre_Class
=> True,
147 Pragma_Precondition
=> True,
148 Pragma_Predicate
=> True,
149 Pragma_Refined_Post
=> True,
150 Pragma_Test_Case
=> True,
151 Pragma_Type_Invariant
=> True,
152 Pragma_Type_Invariant_Class
=> True,
155 -- The following table lists all the implementation-defined pragmas that
156 -- should apply to the anonymous object produced by the analysis of a
157 -- single protected or task type. The table should be synchronized with
158 -- Aspect_On_Anonymous_Object_OK in unit Aspects.
160 Pragma_On_Anonymous_Object_OK
: constant array (Pragma_Id
) of Boolean :=
161 (Pragma_Depends
=> True,
162 Pragma_Global
=> True,
163 Pragma_Part_Of
=> True,
166 -- The following table lists all the implementation-defined pragmas that
167 -- may apply to a body stub (no language defined pragmas apply). The table
168 -- should be synchronized with Aspect_On_Body_Or_Stub_OK in unit Aspects.
170 Pragma_On_Body_Or_Stub_OK
: constant array (Pragma_Id
) of Boolean :=
171 (Pragma_Refined_Depends
=> True,
172 Pragma_Refined_Global
=> True,
173 Pragma_Refined_Post
=> True,
174 Pragma_SPARK_Mode
=> True,
175 Pragma_Warnings
=> True,
178 -- The following table lists all pragmas which are significant in SPARK and
179 -- as a result get translated into verification conditions. The table is an
180 -- amalgamation of the pragmas listed in SPARK RM 16.1 and internally added
183 Pragma_Significant_In_SPARK
: constant array (Pragma_Id
) of Boolean :=
184 (Pragma_All_Calls_Remote
=> False,
185 Pragma_Asynchronous
=> False,
186 Pragma_Default_Storage_Pool
=> False,
187 Pragma_Discard_Names
=> False,
188 Pragma_Dispatching_Domain
=> False,
189 Pragma_Priority_Specific_Dispatching
=> False,
190 Pragma_Remote_Call_Interface
=> False,
191 Pragma_Remote_Types
=> False,
192 Pragma_Shared_Passive
=> False,
193 Pragma_Task_Dispatching_Policy
=> False,
194 Pragma_Unmodified
=> False,
195 Pragma_Unreferenced
=> False,
196 Pragma_Warnings
=> False,
203 procedure Analyze_Pragma
(N
: Node_Id
);
204 -- Analyze procedure for pragma reference node N
206 procedure Analyze_Contract_Cases_In_Decl_Part
208 Freeze_Id
: Entity_Id
:= Empty
);
209 -- Perform full analysis of delayed pragma Contract_Cases. Freeze_Id is the
210 -- entity of [generic] package body or [generic] subprogram body which
211 -- caused "freezing" of the related contract where the pragma resides.
213 procedure Analyze_Depends_In_Decl_Part
(N
: Node_Id
);
214 -- Perform full analysis of delayed pragma Depends. This routine is also
215 -- capable of performing basic analysis of pragma Refined_Depends.
217 procedure Analyze_External_Property_In_Decl_Part
219 Expr_Val
: out Boolean);
220 -- Perform full analysis of delayed pragmas Async_Readers, Async_Writers,
221 -- Effective_Reads and Effective_Writes. Flag Expr_Val contains the Boolean
222 -- argument of the pragma or a default True if no argument is present.
224 procedure Analyze_Global_In_Decl_Part
(N
: Node_Id
);
225 -- Perform full analysis of delayed pragma Global. This routine is also
226 -- capable of performing basic analysis of pragma Refined_Global.
228 procedure Analyze_Initial_Condition_In_Decl_Part
(N
: Node_Id
);
229 -- Perform full analysis of delayed pragma Initial_Condition
231 procedure Analyze_Initializes_In_Decl_Part
(N
: Node_Id
);
232 -- Perform full analysis of delayed pragma Initializes
234 procedure Analyze_Part_Of_In_Decl_Part
236 Freeze_Id
: Entity_Id
:= Empty
);
237 -- Perform full analysis of delayed pragma Part_Of. Freeze_Id is the entity
238 -- of [generic] package body or [generic] subprogram body which caused the
239 -- "freezing" of the related contract where the pragma resides.
241 procedure Analyze_Pre_Post_Condition_In_Decl_Part
243 Freeze_Id
: Entity_Id
:= Empty
);
244 -- Perform full analysis of pragmas Precondition and Postcondition.
245 -- Freeze_Id denotes the entity of [generic] package body or [generic]
246 -- subprogram body which caused "freezing" of the related contract where
247 -- the pragma resides.
249 procedure Analyze_Refined_Depends_In_Decl_Part
(N
: Node_Id
);
250 -- Preform full analysis of delayed pragma Refined_Depends. This routine
251 -- uses Analyze_Depends_In_Decl_Part as a starting point, then performs
252 -- various consistency checks between Depends and Refined_Depends.
254 procedure Analyze_Refined_Global_In_Decl_Part
(N
: Node_Id
);
255 -- Perform full analysis of delayed pragma Refined_Global. This routine
256 -- uses Analyze_Global_In_Decl_Part as a starting point, then performs
257 -- various consistency checks between Global and Refined_Global.
259 procedure Analyze_Refined_State_In_Decl_Part
261 Freeze_Id
: Entity_Id
:= Empty
);
262 -- Perform full analysis of delayed pragma Refined_State. Freeze_Id denotes
263 -- the entity of [generic] package body or [generic] subprogram body which
264 -- caused "freezing" of the related contract where the pragma resides.
266 procedure Analyze_Test_Case_In_Decl_Part
(N
: Node_Id
);
267 -- Perform preanalysis of pragma Test_Case
269 function Build_Pragma_Check_Equivalent
271 Subp_Id
: Entity_Id
:= Empty
;
272 Inher_Id
: Entity_Id
:= Empty
;
273 Keep_Pragma_Id
: Boolean := False) return Node_Id
;
274 -- Transform a pre- or [refined] postcondition denoted by Prag into an
275 -- equivalent pragma Check. When the pre- or postcondition is inherited,
276 -- the routine replaces the references of all formals of Inher_Id
277 -- and primitive operations of its controlling type by references
278 -- to the corresponding entities of Subp_Id and the descendant type.
279 -- Keep_Pragma_Id is True when the newly created pragma should be
280 -- in fact of the same kind as the source pragma Prag. This is used
281 -- in GNATprove_Mode to generate the inherited pre- and postconditions.
283 procedure Check_Applicable_Policy
(N
: Node_Id
);
284 -- N is either an N_Aspect or an N_Pragma node. There are two cases. If
285 -- the name of the aspect or pragma is not one of those recognized as
286 -- an assertion kind by an Assertion_Policy pragma, then the call has
287 -- no effect. Note that in the case of a pragma derived from an aspect,
288 -- the name we use for the purpose of this procedure is the aspect name,
289 -- which may be different from the pragma name (e.g. Precondition for
290 -- Pre aspect). In addition, 'Class aspects are recognized (and the
291 -- corresponding special names used in the processing).
293 -- If the name is a valid assertion kind name, then the Check_Policy pragma
294 -- chain is checked for a matching entry (or for an Assertion entry which
295 -- matches all possibilities). If a matching entry is found then the policy
296 -- is checked. If it is On or Check, then the Is_Checked flag is set in
297 -- the aspect or pragma node. If it is Off, Ignore, or Disable, then the
298 -- Is_Ignored flag is set in the aspect or pragma node. Additionally for
299 -- policy Disable, the Is_Disabled flag is set.
301 -- If no matching Check_Policy pragma is found then the effect depends on
302 -- whether -gnata was used, if so, then the call has no effect, otherwise
303 -- Is_Ignored (but not Is_Disabled) is set True.
305 procedure Check_External_Properties
311 -- Flags AR, AW, ER and EW denote the static values of external properties
312 -- Async_Readers, Async_Writers, Effective_Reads and Effective_Writes. Item
313 -- is the related variable or state. Ensure legality of the combination and
314 -- issue an error for an illegal combination.
316 function Check_Kind
(Nam
: Name_Id
) return Name_Id
;
317 -- This function is used in connection with pragmas Assert, Check,
318 -- and assertion aspects and pragmas, to determine if Check pragmas
319 -- (or corresponding assertion aspects or pragmas) are currently active
320 -- as determined by the presence of -gnata on the command line (which
321 -- sets the default), and the appearance of pragmas Check_Policy and
322 -- Assertion_Policy as configuration pragmas either in a configuration
323 -- pragma file, or at the start of the current unit, or locally given
324 -- Check_Policy and Assertion_Policy pragmas that are currently active.
326 -- The value returned is one of the names Check, Ignore, Disable (On
327 -- returns Check, and Off returns Ignore).
329 -- Note: for assertion kinds Pre'Class, Post'Class, Invariant'Class,
330 -- and Type_Invariant'Class, the name passed is Name_uPre, Name_uPost,
331 -- Name_uInvariant, or Name_uType_Invariant, which corresponds to _Pre,
332 -- _Post, _Invariant, or _Type_Invariant, which are special names used
333 -- in identifiers to represent these attribute references.
335 procedure Check_Missing_Part_Of
(Item_Id
: Entity_Id
);
336 -- Determine whether the placement within the state space of an abstract
337 -- state, variable or package instantiation denoted by Item_Id requires the
338 -- use of indicator/option Part_Of. If this is the case, emit an error.
340 procedure Collect_Inherited_Class_Wide_Conditions
(Subp
: Entity_Id
);
341 -- In GNATprove mode, when analyzing an overriding subprogram, check
342 -- whether the overridden operations have class-wide pre/postconditions,
343 -- and generate the corresponding pragmas. The pragmas are inserted after
344 -- the subprogram declaration, together with those generated for other
345 -- aspects of the subprogram.
347 procedure Collect_Subprogram_Inputs_Outputs
348 (Subp_Id
: Entity_Id
;
349 Synthesize
: Boolean := False;
350 Subp_Inputs
: in out Elist_Id
;
351 Subp_Outputs
: in out Elist_Id
;
352 Global_Seen
: out Boolean);
353 -- Subsidiary to the analysis of pragmas Depends, Global, Refined_Depends
354 -- and Refined_Global. The routine is also used by GNATprove. Collect all
355 -- inputs and outputs of subprogram Subp_Id in lists Subp_Inputs (inputs)
356 -- and Subp_Outputs (outputs). The inputs and outputs are gathered from:
357 -- 1) The formal parameters of the subprogram
358 -- 2) The generic formal parameters of the generic subprogram
359 -- 3) The current instance of a concurrent type
360 -- 4) The items of pragma [Refined_]Global
362 -- 5) The items of pragma [Refined_]Depends if there is no pragma
363 -- [Refined_]Global present and flag Synthesize is set to True.
364 -- If the subprogram has no inputs and/or outputs, then the returned list
365 -- is No_Elist. Flag Global_Seen is set when the related subprogram has
366 -- pragma [Refined_]Global.
368 function Delay_Config_Pragma_Analyze
(N
: Node_Id
) return Boolean;
369 -- N is a pragma appearing in a configuration pragma file. Most such
370 -- pragmas are analyzed when the file is read, before parsing and analyzing
371 -- the main unit. However, the analysis of certain pragmas results in
372 -- adding information to the compiled main unit, and this cannot be done
373 -- till the main unit is processed. Such pragmas return True from this
374 -- function and in Frontend pragmas where Delay_Config_Pragma_Analyze is
375 -- True have their analysis delayed until after the main program is parsed
378 function Find_Related_Package_Or_Body
380 Do_Checks
: Boolean := False) return Node_Id
;
381 -- Subsidiary to the analysis of pragmas
386 -- Find the declaration of the related package [body] subject to pragma
387 -- Prag. The return value is either N_Package_Declaration, N_Package_Body,
388 -- or Empty if the placement of the pragma is illegal. If flag Do_Checks is
389 -- set, the routine reports duplicate pragmas.
391 function Find_Related_Declaration_Or_Body
393 Do_Checks
: Boolean := False) return Node_Id
;
394 -- Subsidiary to the analysis of pragmas
397 -- Extensions_Visible
413 -- as well as attributes 'Old and 'Result. Find the declaration of the
414 -- related entry, subprogram or task type [body] subject to pragma Prag.
415 -- If flag Do_Checks is set, the routine reports duplicate pragmas and
416 -- detects improper use of refinement pragmas in stand alone expression
419 function Get_Argument
421 Context_Id
: Node_Id
:= Empty
) return Node_Id
;
422 -- Obtain the argument of pragma Prag depending on context and the nature
423 -- of the pragma. The argument is extracted in the following manner:
425 -- When the pragma is generated from an aspect, return the corresponding
426 -- aspect for ASIS or when Context_Id denotes a generic unit.
428 -- Otherwise return the first argument of Prag
430 -- Context denotes the entity of the function, package or procedure where
433 function Get_SPARK_Mode_From_Annotation
434 (N
: Node_Id
) return SPARK_Mode_Type
;
435 -- Given an aspect or pragma SPARK_Mode node, return corresponding mode id
437 procedure Initialize
;
438 -- Initializes data structures used for pragma processing. Must be called
439 -- before analyzing each new main source program.
441 function Is_Config_Static_String
(Arg
: Node_Id
) return Boolean;
442 -- This is called for a configuration pragma that requires either string
443 -- literal or a concatenation of string literals. We cannot use normal
444 -- static string processing because it is too early in the case of the
445 -- pragma appearing in a configuration pragmas file. If Arg is of an
446 -- appropriate form, then this call obtains the string (doing any necessary
447 -- concatenations) and places it in Name_Buffer, setting Name_Len to its
448 -- length, and then returns True. If it is not of the correct form, then an
449 -- appropriate error message is posted, and False is returned.
451 function Is_Elaboration_SPARK_Mode
(N
: Node_Id
) return Boolean;
452 -- Determine whether pragma SPARK_Mode appears in the statement part of a
455 function Is_Enabled_Pragma
(Prag
: Node_Id
) return Boolean;
456 -- Determine whether a Boolean-like SPARK pragma Prag is enabled. To be
457 -- considered enabled, the pragma must either:
458 -- * Appear without its Boolean expression
459 -- * The Boolean expression evaluates to "True"
461 -- Boolean-like SPARK pragmas differ from pure Boolean Ada pragmas in that
462 -- their optional Boolean expression must be static and cannot benefit from
463 -- forward references. The following are Boolean-like SPARK pragmas:
466 -- Constant_After_Elaboration
469 -- Extensions_Visible
472 function Is_Non_Significant_Pragma_Reference
(N
: Node_Id
) return Boolean;
473 -- The node N is a node for an entity and the issue is whether the
474 -- occurrence is a reference for the purposes of giving warnings about
475 -- unreferenced variables. This function returns True if the reference is
476 -- not a reference from this point of view (e.g. the occurrence in a pragma
477 -- Pack) and False if it is a real reference (e.g. the occurrence in a
480 function Is_Pragma_String_Literal
(Par
: Node_Id
) return Boolean;
481 -- Given an N_Pragma_Argument_Association node, Par, which has the form of
482 -- an operator symbol, determines whether or not it should be treated as an
483 -- string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol. If
484 -- True is returned, the argument is converted to a string literal. If
485 -- False is returned, then the argument is treated as an entity reference
488 function Is_Private_SPARK_Mode
(N
: Node_Id
) return Boolean;
489 -- Determine whether pragma SPARK_Mode appears in the private part of a
492 function Is_Valid_Assertion_Kind
(Nam
: Name_Id
) return Boolean;
493 -- Returns True if Nam is one of the names recognized as a valid assertion
494 -- kind by the Assertion_Policy pragma. Note that the 'Class cases are
495 -- represented by the corresponding special names Name_uPre, Name_uPost,
496 -- Name_uInvariant, and Name_uType_Invariant (_Pre, _Post, _Invariant,
497 -- and _Type_Invariant).
499 procedure Process_Compile_Time_Warning_Or_Error
502 -- Common processing for Compile_Time_Error and Compile_Time_Warning of
503 -- pragma N. Called when the pragma is processed as part of its regular
504 -- analysis but also called after calling the back end to validate these
505 -- pragmas for size and alignment appropriateness.
507 procedure Process_Compilation_Unit_Pragmas
(N
: Node_Id
);
508 -- Called at the start of processing compilation unit N to deal with any
509 -- special issues regarding pragmas. In particular, we have to deal with
510 -- Suppress_All at this stage, since it can appear after the unit instead
511 -- of before (actually we allow it to appear anywhere).
513 procedure Relocate_Pragmas_To_Anonymous_Object
516 -- Relocate all pragmas that appear in the visible declarations of task or
517 -- protected type declaration Typ_Decl after the declaration of anonymous
518 -- object Obj_Decl. Table Pragmas_On_Anonymous_Object_OK contains the list
519 -- of candidate pragmas.
521 procedure Relocate_Pragmas_To_Body
522 (Subp_Body
: Node_Id
;
523 Target_Body
: Node_Id
:= Empty
);
524 -- Resocate all pragmas that follow and apply to subprogram body Subp_Body
525 -- to its own declaration list. Candidate pragmas are classified in table
526 -- Pragma_On_Body_Or_Stub_OK. If Target_Body is set, the pragma are moved
527 -- to the declarations of Target_Body. This formal should be set when
528 -- dealing with subprogram body stubs or expression functions.
530 procedure Set_Encoded_Interface_Name
(E
: Entity_Id
; S
: Node_Id
);
531 -- This routine is used to set an encoded interface name. The node S is
532 -- an N_String_Literal node for the external name to be set, and E is an
533 -- entity whose Interface_Name field is to be set. In the normal case where
534 -- S contains a name that is a valid C identifier, then S is simply set as
535 -- the value of the Interface_Name. Otherwise it is encoded as needed by
536 -- particular operating systems. See the body for details of the encoding.
538 function Test_Case_Arg
541 From_Aspect
: Boolean := False) return Node_Id
;
542 -- Obtain argument "Name", "Mode", "Ensures" or "Requires" from Test_Case
543 -- pragma Prag as denoted by Arg_Nam. When From_Aspect is set, an attempt
544 -- is made to retrieve the argument from the corresponding aspect if there
545 -- is one. The returned argument has several formats:
547 -- N_Pragma_Argument_Association if retrieved directly from the pragma
549 -- N_Component_Association if retrieved from the corresponding aspect and
550 -- the argument appears in a named association form.
552 -- An arbitrary expression if retrieved from the corresponding aspect and
553 -- the argument appears in positional form.
555 -- Empty if there is no such argument