1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2015, 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_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,
127 -- The following table lists all pragmas that act as an assertion
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,
142 Pragma_Post_Class
=> True,
143 Pragma_Postcondition
=> 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,
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.
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,
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.
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,
181 procedure Analyze_Pragma
(N
: Node_Id
);
182 -- Analyze procedure for pragma reference node N
184 procedure Analyze_Contract_Cases_In_Decl_Part
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.
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.
195 procedure Analyze_External_Property_In_Decl_Part
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.
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.
206 procedure Analyze_Initial_Condition_In_Decl_Part
(N
: Node_Id
);
207 -- Perform full analysis of delayed pragma Initial_Condition
209 procedure Analyze_Initializes_In_Decl_Part
(N
: Node_Id
);
210 -- Perform full analysis of delayed pragma Initializes
212 procedure Analyze_Part_Of_In_Decl_Part
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.
219 procedure Analyze_Pre_Post_Condition_In_Decl_Part
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.
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.
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.
237 procedure Analyze_Refined_State_In_Decl_Part
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.
244 procedure Analyze_Test_Case_In_Decl_Part
(N
: Node_Id
);
245 -- Perform preanalysis of pragma Test_Case
247 function Build_Pragma_Check_Equivalent
249 Subp_Id
: Entity_Id
:= Empty
;
250 Inher_Id
: Entity_Id
:= Empty
) return Node_Id
;
251 -- Transform a [refined] pre- or postcondition denoted by Prag into an
252 -- equivalent pragma Check. When the pre- or postcondition is inherited,
253 -- the routine replaces the references of all formals of Inher_Id and
254 -- primitive operations of its controlling type by references to the
255 -- corresponding entities of Subp_Id and the descendant type.
257 procedure Check_Applicable_Policy
(N
: Node_Id
);
258 -- N is either an N_Aspect or an N_Pragma node. There are two cases. If
259 -- the name of the aspect or pragma is not one of those recognized as
260 -- an assertion kind by an Assertion_Policy pragma, then the call has
261 -- no effect. Note that in the case of a pragma derived from an aspect,
262 -- the name we use for the purpose of this procedure is the aspect name,
263 -- which may be different from the pragma name (e.g. Precondition for
264 -- Pre aspect). In addition, 'Class aspects are recognized (and the
265 -- corresponding special names used in the processing).
267 -- If the name is a valid assertion kind name, then the Check_Policy pragma
268 -- chain is checked for a matching entry (or for an Assertion entry which
269 -- matches all possibilities). If a matching entry is found then the policy
270 -- is checked. If it is On or Check, then the Is_Checked flag is set in
271 -- the aspect or pragma node. If it is Off, Ignore, or Disable, then the
272 -- Is_Ignored flag is set in the aspect or pragma node. Additionally for
273 -- policy Disable, the Is_Disabled flag is set.
275 -- If no matching Check_Policy pragma is found then the effect depends on
276 -- whether -gnata was used, if so, then the call has no effect, otherwise
277 -- Is_Ignored (but not Is_Disabled) is set True.
279 procedure Check_External_Properties
285 -- Flags AR, AW, ER and EW denote the static values of external properties
286 -- Async_Readers, Async_Writers, Effective_Reads and Effective_Writes. Item
287 -- is the related variable or state. Ensure legality of the combination and
288 -- issue an error for an illegal combination.
290 function Check_Kind
(Nam
: Name_Id
) return Name_Id
;
291 -- This function is used in connection with pragmas Assert, Check,
292 -- and assertion aspects and pragmas, to determine if Check pragmas
293 -- (or corresponding assertion aspects or pragmas) are currently active
294 -- as determined by the presence of -gnata on the command line (which
295 -- sets the default), and the appearance of pragmas Check_Policy and
296 -- Assertion_Policy as configuration pragmas either in a configuration
297 -- pragma file, or at the start of the current unit, or locally given
298 -- Check_Policy and Assertion_Policy pragmas that are currently active.
300 -- The value returned is one of the names Check, Ignore, Disable (On
301 -- returns Check, and Off returns Ignore).
303 -- Note: for assertion kinds Pre'Class, Post'Class, Invariant'Class,
304 -- and Type_Invariant'Class, the name passed is Name_uPre, Name_uPost,
305 -- Name_uInvariant, or Name_uType_Invariant, which corresponds to _Pre,
306 -- _Post, _Invariant, or _Type_Invariant, which are special names used
307 -- in identifiers to represent these attribute references.
309 procedure Check_Missing_Part_Of
(Item_Id
: Entity_Id
);
310 -- Determine whether the placement within the state space of an abstract
311 -- state, variable or package instantiation denoted by Item_Id requires the
312 -- use of indicator/option Part_Of. If this is the case, emit an error.
314 procedure Collect_Inherited_Class_Wide_Conditions
(Subp
: Entity_Id
);
315 -- In GNATprove mode, when analyzing an overriding subprogram, check
316 -- whether the overridden operations have class-wide pre/postconditions,
317 -- and generate the corresponding pragmas. The pragmas are inserted after
318 -- the subprogram declaration, together with those generated for other
319 -- aspects of the subprogram.
321 procedure Collect_Subprogram_Inputs_Outputs
322 (Subp_Id
: Entity_Id
;
323 Synthesize
: Boolean := False;
324 Subp_Inputs
: in out Elist_Id
;
325 Subp_Outputs
: in out Elist_Id
;
326 Global_Seen
: out Boolean);
327 -- Subsidiary to the analysis of pragmas Depends, Global, Refined_Depends
328 -- and Refined_Global. The routine is also used by GNATprove. Collect all
329 -- inputs and outputs of subprogram Subp_Id in lists Subp_Inputs (inputs)
330 -- and Subp_Outputs (outputs). The inputs and outputs are gathered from:
331 -- 1) The formal parameters of the subprogram
332 -- 2) The generic formal parameters of the generic subprogram
333 -- 3) The current instance of a concurrent type
334 -- 4) The items of pragma [Refined_]Global
336 -- 5) The items of pragma [Refined_]Depends if there is no pragma
337 -- [Refined_]Global present and flag Synthesize is set to True.
338 -- If the subprogram has no inputs and/or outputs, then the returned list
339 -- is No_Elist. Flag Global_Seen is set when the related subprogram has
340 -- pragma [Refined_]Global.
342 function Delay_Config_Pragma_Analyze
(N
: Node_Id
) return Boolean;
343 -- N is a pragma appearing in a configuration pragma file. Most such
344 -- pragmas are analyzed when the file is read, before parsing and analyzing
345 -- the main unit. However, the analysis of certain pragmas results in
346 -- adding information to the compiled main unit, and this cannot be done
347 -- till the main unit is processed. Such pragmas return True from this
348 -- function and in Frontend pragmas where Delay_Config_Pragma_Analyze is
349 -- True have their analysis delayed until after the main program is parsed
352 function Find_Related_Package_Or_Body
354 Do_Checks
: Boolean := False) return Node_Id
;
355 -- Subsidiary to the analysis of pragmas Abstract_State, Initial_Condition,
356 -- Initializes and Refined_State. Find the declaration of the related
357 -- package [body] subject to pragma Prag. The return value is either
358 -- N_Package_Declaration, N_Package_Body or Empty if the placement of
359 -- the pragma is illegal. If flag Do_Checks is set, the routine reports
360 -- duplicate pragmas.
362 function Find_Related_Declaration_Or_Body
364 Do_Checks
: Boolean := False) return Node_Id
;
365 -- Subsidiary to the analysis of pragmas
368 -- Extensions_Visible
380 -- as well as attributes 'Old and 'Result. Find the declaration of the
381 -- related entry, subprogram or task type [body] subject to pragma Prag.
382 -- If flag Do_Checks is set, the routine reports duplicate pragmas and
383 -- detects improper use of refinement pragmas in stand alone expression
386 function Get_Argument
388 Context_Id
: Node_Id
:= Empty
) return Node_Id
;
389 -- Obtain the argument of pragma Prag depending on context and the nature
390 -- of the pragma. The argument is extracted in the following manner:
392 -- When the pragma is generated from an aspect, return the corresponding
393 -- aspect for ASIS or when Context_Id denotes a generic unit.
395 -- Otherwise return the first argument of Prag
397 -- Context denotes the entity of the function, package or procedure where
400 function Get_SPARK_Mode_From_Annotation
401 (N
: Node_Id
) return SPARK_Mode_Type
;
402 -- Given an aspect or pragma SPARK_Mode node, return corresponding mode id
404 procedure Initialize
;
405 -- Initializes data structures used for pragma processing. Must be called
406 -- before analyzing each new main source program.
408 function Is_Config_Static_String
(Arg
: Node_Id
) return Boolean;
409 -- This is called for a configuration pragma that requires either string
410 -- literal or a concatenation of string literals. We cannot use normal
411 -- static string processing because it is too early in the case of the
412 -- pragma appearing in a configuration pragmas file. If Arg is of an
413 -- appropriate form, then this call obtains the string (doing any necessary
414 -- concatenations) and places it in Name_Buffer, setting Name_Len to its
415 -- length, and then returns True. If it is not of the correct form, then an
416 -- appropriate error message is posted, and False is returned.
418 function Is_Elaboration_SPARK_Mode
(N
: Node_Id
) return Boolean;
419 -- Determine whether pragma SPARK_Mode appears in the statement part of a
422 function Is_Enabled_Pragma
(Prag
: Node_Id
) return Boolean;
423 -- Determine whether a Boolean-like SPARK pragma Prag is enabled. To be
424 -- considered enabled, the pragma must either:
425 -- * Appear without its Boolean expression
426 -- * The Boolean expression evaluates to "True"
428 -- Boolean-like SPARK pragmas differ from pure Boolean Ada pragmas in that
429 -- their optional Boolean expression must be static and cannot benefit from
430 -- forward references. The following are Boolean-like SPARK pragmas:
433 -- Constant_After_Elaboration
436 -- Extensions_Visible
439 function Is_Non_Significant_Pragma_Reference
(N
: Node_Id
) return Boolean;
440 -- The node N is a node for an entity and the issue is whether the
441 -- occurrence is a reference for the purposes of giving warnings about
442 -- unreferenced variables. This function returns True if the reference is
443 -- not a reference from this point of view (e.g. the occurrence in a pragma
444 -- Pack) and False if it is a real reference (e.g. the occurrence in a
447 function Is_Pragma_String_Literal
(Par
: Node_Id
) return Boolean;
448 -- Given an N_Pragma_Argument_Association node, Par, which has the form of
449 -- an operator symbol, determines whether or not it should be treated as an
450 -- string literal. This is called by Sem_Ch6.Analyze_Operator_Symbol. If
451 -- True is returned, the argument is converted to a string literal. If
452 -- False is returned, then the argument is treated as an entity reference
455 function Is_Private_SPARK_Mode
(N
: Node_Id
) return Boolean;
456 -- Determine whether pragma SPARK_Mode appears in the private part of a
459 function Is_Valid_Assertion_Kind
(Nam
: Name_Id
) return Boolean;
460 -- Returns True if Nam is one of the names recognized as a valid assertion
461 -- kind by the Assertion_Policy pragma. Note that the 'Class cases are
462 -- represented by the corresponding special names Name_uPre, Name_uPost,
463 -- Name_uInvariant, and Name_uType_Invariant (_Pre, _Post, _Invariant,
464 -- and _Type_Invariant).
466 procedure Process_Compilation_Unit_Pragmas
(N
: Node_Id
);
467 -- Called at the start of processing compilation unit N to deal with any
468 -- special issues regarding pragmas. In particular, we have to deal with
469 -- Suppress_All at this stage, since it can appear after the unit instead
470 -- of before (actually we allow it to appear anywhere).
472 procedure Relocate_Pragmas_To_Anonymous_Object
475 -- Relocate all pragmas that appear in the visible declarations of task or
476 -- protected type declaration Typ_Decl after the declaration of anonymous
477 -- object Obj_Decl. Table Pragmas_On_Anonymous_Object_OK contains the list
478 -- of candidate pragmas.
480 procedure Relocate_Pragmas_To_Body
481 (Subp_Body
: Node_Id
;
482 Target_Body
: Node_Id
:= Empty
);
483 -- Resocate all pragmas that follow and apply to subprogram body Subp_Body
484 -- to its own declaration list. Candidate pragmas are classified in table
485 -- Pragma_On_Body_Or_Stub_OK. If Target_Body is set, the pragma are moved
486 -- to the declarations of Target_Body. This formal should be set when
487 -- dealing with subprogram body stubs or expression functions.
489 procedure Set_Encoded_Interface_Name
(E
: Entity_Id
; S
: Node_Id
);
490 -- This routine is used to set an encoded interface name. The node S is
491 -- an N_String_Literal node for the external name to be set, and E is an
492 -- entity whose Interface_Name field is to be set. In the normal case where
493 -- S contains a name that is a valid C identifier, then S is simply set as
494 -- the value of the Interface_Name. Otherwise it is encoded as needed by
495 -- particular operating systems. See the body for details of the encoding.
497 function Test_Case_Arg
500 From_Aspect
: Boolean := False) return Node_Id
;
501 -- Obtain argument "Name", "Mode", "Ensures" or "Requires" from Test_Case
502 -- pragma Prag as denoted by Arg_Nam. When From_Aspect is set, an attempt
503 -- is made to retrieve the argument from the corresponding aspect if there
504 -- is one. The returned argument has several formats:
506 -- N_Pragma_Argument_Association if retrieved directly from the pragma
508 -- N_Component_Association if retrieved from the corresponding aspect and
509 -- the argument appears in a named association form.
511 -- An arbitrary expression if retrieved from the corresponding aspect and
512 -- the argument appears in positional form.
514 -- Empty if there is no such argument