| blob | 5aef17df8ec3bf88cfef06327d1eb9ac9ef46855 |
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ A T T R --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2017, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
86 -- Synonyms to be used when these constants are used as Boolean values
89 -- Exception raised if an error is detected during attribute processing,
90 -- used so that we can abandon the processing so we don't run into
91 -- trouble with cascaded errors.
93 -- The following array is the list of attributes defined in the Ada 83 RM.
94 -- In Ada 83 mode, these are the only recognized attributes. In other Ada
95 -- modes all these attributes are recognized, even if removed in Ada 95.
98 Attribute_Address |
99 Attribute_Aft |
100 Attribute_Alignment |
101 Attribute_Base |
102 Attribute_Callable |
103 Attribute_Constrained |
104 Attribute_Count |
105 Attribute_Delta |
106 Attribute_Digits |
107 Attribute_Emax |
108 Attribute_Epsilon |
109 Attribute_First |
110 Attribute_First_Bit |
111 Attribute_Fore |
112 Attribute_Image |
113 Attribute_Large |
114 Attribute_Last |
115 Attribute_Last_Bit |
116 Attribute_Leading_Part |
117 Attribute_Length |
118 Attribute_Machine_Emax |
119 Attribute_Machine_Emin |
120 Attribute_Machine_Mantissa |
121 Attribute_Machine_Overflows |
122 Attribute_Machine_Radix |
123 Attribute_Machine_Rounds |
124 Attribute_Mantissa |
125 Attribute_Pos |
126 Attribute_Position |
127 Attribute_Pred |
128 Attribute_Range |
129 Attribute_Safe_Emax |
130 Attribute_Safe_Large |
131 Attribute_Safe_Small |
132 Attribute_Size |
133 Attribute_Small |
134 Attribute_Storage_Size |
135 Attribute_Succ |
136 Attribute_Terminated |
137 Attribute_Val |
138 Attribute_Value |
139 Attribute_Width => True,
140 others => False);
142 -- The following array is the list of attributes defined in the Ada 2005
143 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
144 -- but in Ada 95 they are considered to be implementation defined.
147 Attribute_Machine_Rounding |
148 Attribute_Mod |
149 Attribute_Priority |
150 Attribute_Stream_Size |
154 -- The following array is the list of attributes defined in the Ada 2012
155 -- RM which are not defined in Ada 2005. These are recognized in Ada 95
156 -- and Ada 2005 modes, but are considered to be implementation defined.
159 Attribute_First_Valid |
160 Attribute_Has_Same_Storage |
161 Attribute_Last_Valid |
162 Attribute_Max_Alignment_For_Allocation => True,
163 others => False);
165 -- The following array contains all attributes that imply a modification
166 -- of their prefixes or result in an access value. Such prefixes can be
167 -- considered as lvalues.
169 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
171 Attribute_Access |
172 Attribute_Address |
173 Attribute_Input |
174 Attribute_Read |
175 Attribute_Unchecked_Access |
179 -----------------------
180 -- Local_Subprograms --
181 -----------------------
184 -- Performs compile time evaluation of attributes where possible, leaving
185 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
186 -- set, and replacing the node with a literal node if the value can be
187 -- computed at compile time. All static attribute references are folded,
188 -- as well as a number of cases of non-static attributes that can always
189 -- be computed at compile time (e.g. floating-point model attributes that
190 -- are applied to non-static subtypes). Of course in such cases, the
191 -- Is_Static_Expression flag will not be set on the resulting literal.
192 -- Note that the only required action of this procedure is to catch the
193 -- static expression cases as described in the RM. Folding of other cases
194 -- is done where convenient, but some additional non-static folding is in
195 -- Expand_N_Attribute_Reference in cases where this is more convenient.
197 function Is_Anonymous_Tagged_Base
200 -- For derived tagged types that constrain parent discriminants we build
201 -- an anonymous unconstrained base type. We need to recognize the relation
202 -- between the two when analyzing an access attribute for a constrained
203 -- component, before the full declaration for Typ has been analyzed, and
204 -- where therefore the prefix of the attribute does not match the enclosing
205 -- scope.
208 -- Rewrites node N with an occurrence of either Standard_False or
209 -- Standard_True, depending on the value of the parameter B. The
210 -- result is marked as a static expression.
213 -- Predicate used to check the legality of the prefix to 'Loop_Entry and
214 -- 'Old, when the prefix is not an entity name. Current RM specfies that
215 -- the prefix must be a direct or expanded name, but it has been proposed
216 -- that the prefix be allowed to be a selected component that does not
217 -- depend on a discriminant, or an indexed component with static indices.
218 -- Current code for this predicate implements this more permissive
219 -- implementation.
221 -----------------------
222 -- Analyze_Attribute --
223 -----------------------
235 -- Type of prefix after analysis
238 -- Base type of prefix after analysis
240 -----------------------
241 -- Local Subprograms --
242 -----------------------
245 -- Semantic checks for valid use of Address attribute. This was made
246 -- a separate routine with the idea of using it for unrestricted access
247 -- which seems like it should follow the same rules, but that turned
248 -- out to be impractical. So now this is only used for Address.
251 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
252 -- Internally, Id distinguishes which of the three cases is involved.
254 procedure Analyze_Attribute_Old_Result
257 -- Common processing for attributes 'Old and 'Result. The routine checks
258 -- that the attribute appears in a postcondition-like aspect or pragma
259 -- associated with a suitable subprogram or a body. Flag Legal is set
260 -- when the above criteria are met. Spec_Id denotes the entity of the
261 -- subprogram [body] or Empty if the attribute is illegal.
264 -- Common processing for attributes 'Img, 'Image, 'Wide_Image, and
265 -- 'Wide_Wide_Image. The routine checks that the prefix is valid and
266 -- sets the type of the attribute to the one specified by Str_Typ (e.g.
267 -- Standard_String for 'Image and Standard_Wide_String for 'Wide_Image).
270 -- Output error message for use of a predicate (First, Last, Range) not
271 -- allowed with a type that has predicates. If the type is a generic
272 -- actual, then the message is a warning, and we generate code to raise
273 -- program error with an appropriate reason. No error message is given
274 -- for internally generated uses of the attributes. This legality rule
275 -- only applies to scalar types.
278 -- Common procedure used by First, Last, Range attribute to check
279 -- that the prefix is a constrained array or scalar type, or a name
280 -- of an array object, and that an argument appears only if appropriate
281 -- (i.e. only in the array case).
284 -- Common semantic checks for all array attributes. Checks that the
285 -- prefix is a constrained array type or the name of an array object.
286 -- The error message for non-arrays is specialized appropriately.
289 -- Common semantic checks for Asm_Input and Asm_Output attributes
292 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
293 -- Position. Checks prefix is an appropriate selected component.
296 -- Check that prefix of attribute N is a decimal fixed-point type
299 -- If the prefix of attribute is an object of an access type, then
300 -- introduce an explicit dereference, and adjust P_Type accordingly.
303 -- Verify that prefix of attribute N is a discrete type
306 -- Check that no attribute arguments are present
309 -- Check that there are zero or one attribute arguments present
312 -- Check that exactly one attribute argument is present
315 -- Check that two attribute arguments are present
318 -- If the prefix type of 'Image is an enumeration type, set all its
319 -- literals as referenced, since the image function could possibly end
320 -- up referencing any of the literals indirectly. Same for Enum_Val.
321 -- Set the flag only if the reference is in the main code unit. Same
322 -- restriction when resolving 'Value; otherwise an improperly set
323 -- reference when analyzing an inlined body will lose a proper
324 -- warning on a useless with_clause.
327 -- Perform all checks for First_Valid and Last_Valid attributes
330 -- Verify that prefix of attribute N is a fixed type
333 -- Verify that prefix of attribute N is a fixed type and that
334 -- no attribute expressions are present.
337 -- Verify that prefix of attribute N is a float type
340 -- Verify that prefix of attribute N is a float type and that
341 -- no attribute expressions are present.
344 -- Verify that prefix of attribute N is a float type and that
345 -- exactly one attribute expression is present.
348 -- Verify that prefix of attribute N is a float type and that
349 -- two attribute expressions are present
352 -- Issue an error in formal mode because attribute N is allowed
355 -- Verify that prefix of attribute N is an integer type
358 -- Verify that prefix of attribute N is a modular integer type
361 -- Check that P (the prefix of the attribute) is not an CPP type
362 -- for which no Ada predefined primitive is available.
365 -- Check that P (the prefix of the attribute) is not an incomplete
366 -- type or a private type for which no full view has been given.
369 -- Check that P is an object reference
372 -- Validity checking for PolyORB/DSA attribute
375 -- Verify that prefix of attribute N is a program unit
378 -- Verify that prefix of attribute N is fixed or float type
381 -- Verify that prefix of attribute N is a scalar type
384 -- Verify that prefix of attribute N is package Standard. Also checks
385 -- that there are no arguments.
388 -- Validity checking for stream attribute. Nam is the TSS name of the
389 -- corresponding possible defined attribute function (e.g. for the
390 -- Read attribute, Nam will be TSS_Stream_Read).
393 -- Verify that prefix of attribute N is package System
396 -- Verify that prefix of attribute N is a task or task type
399 -- Verify that the prefix of attribute N is a type
402 -- Check that Nod is of the form of a library unit name, i.e that
403 -- it is an identifier, or a selected component whose prefix is
404 -- itself of the form of a library unit name. Note that this is
405 -- quite different from Check_Program_Unit, since it only checks
406 -- the syntactic form of the name, not the semantic identity. This
407 -- is because it is used with attributes (Elab_Body, Elab_Spec and
408 -- Elaborated) which can refer to non-visible unit.
414 -- Posts error using Error_Msg_N at given node, sets type of attribute
415 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
416 -- semantic processing. The message typically contains a % insertion
417 -- character which is replaced by the attribute name. The call with
418 -- no arguments is used when the caller has already generated the
419 -- required error messages.
423 -- Like Error_Attr, but error is posted at the start of the prefix
426 -- Common processing for attributes Definite and Has_Discriminants.
427 -- Checks that prefix is generic indefinite formal type.
430 -- Common processing for attributes Max_Alignment_For_Allocation and
431 -- Max_Size_In_Storage_Elements.
434 -- Common processing for attributes Max and Min
437 -- Used to process attributes whose prefix is package Standard which
438 -- yield values of type Universal_Integer. The attribute reference
439 -- node is rewritten with an integer literal of the given value which
440 -- is marked as static.
443 -- Called when Loop_Entry or Old is used in a potentially unevaluated
444 -- expression. Generates appropriate message or warning depending on
445 -- the setting of Opt.Uneval_Old (or flags in an N_Aspect_Specification
446 -- node in the aspect case).
449 -- Signal unexpected attribute argument (En is the argument)
452 -- Called when processing an attribute that is a function call to a
453 -- non-static function, i.e. an attribute function that either takes
454 -- non-scalar arguments or returns a non-scalar result. Verifies that
455 -- such a call does not appear in a preelaborable context.
457 --------------------
458 -- Address_Checks --
459 --------------------
462 begin
463 -- An Address attribute created by expansion is legal even when it
464 -- applies to other entity-denoting expressions.
469 -- Address attribute on a protected object self reference is legal
474 -- Address applied to an entity
477 declare
480 begin
485 -- An Address attribute is accepted when generated by the
486 -- compiler for dispatching operation, and an error is
487 -- issued once the subprogram is frozen (to avoid confusing
488 -- errors about implicit uses of Address in the dispatch
489 -- table initialization).
493 then
494 Error_Attr_P
498 -- It is illegal to apply 'Address to an intrinsic
499 -- subprogram. This is now formalized in AI05-0095.
500 -- In an instance, an attempt to obtain 'Address of an
501 -- intrinsic subprogram (e.g the renaming of a predefined
502 -- operator that is an actual) raises Program_Error.
510 else
512 Error_Msg_N
516 -- Issue an error if prefix denotes an eliminated subprogram
518 else
522 -- Object or label reference
527 -- Deal with No_Implicit_Aliasing restriction
532 else
537 -- If we have an address of an object, and the attribute
538 -- comes from source, then set the object as potentially
539 -- source modified. We do this because the resulting address
540 -- can potentially be used to modify the variable and we
541 -- might not detect this, leading to some junk warnings.
545 -- Allow Address to be applied to task or protected type,
546 -- returning null address (what is that about???)
552 then
556 -- Anything else is illegal
558 else
563 -- Object is OK
568 -- Subprogram called using dot notation
572 then
575 -- What exactly are we allowing here ??? and is this properly
576 -- documented in the sinfo documentation for this node ???
578 elsif Relaxed_RM_Semantics
580 then
583 -- All other non-entity name cases are illegal
585 else
590 ------------------------------
591 -- Analyze_Access_Attribute --
592 ------------------------------
601 -- Build an access-to-object type whose designated type is DT,
602 -- and whose Ekind is appropriate to the attribute type. The
603 -- type that is constructed is returned as the result.
606 -- Build an access to subprogram whose designated type is the type of
607 -- the prefix. If prefix is overloaded, so is the node itself. The
608 -- result is stored in Acc_Type.
611 -- An access reference whose prefix is a type can legally appear
612 -- within an aggregate, where it is obtained by expansion of
613 -- a defaulted aggregate. The enclosing aggregate that contains
614 -- the self-referenced is flagged so that the self-reference can
615 -- be expanded into a reference to the target object (see exp_aggr).
617 ------------------------------
618 -- Build_Access_Object_Type --
619 ------------------------------
623 New_Internal_Entity
625 begin
633 ----------------------------------
634 -- Build_Access_Subprogram_Type --
635 ----------------------------------
642 -- Deal with possible access to local subprogram. If we have such
643 -- an access, we set a flag to kill all tracked values on any call
644 -- because this access value may be passed around, and any called
645 -- code might use it to access a local procedure which clobbers a
646 -- tracked value. If the scope is a loop or block, indicate that
647 -- value tracking is disabled for the enclosing subprogram.
650 -- Distinguish between access to regular/protected subprograms
652 ------------------------
653 -- Check_Local_Access --
654 ------------------------
657 begin
660 Set_Suppress_Value_Tracking_On_Call
665 --------------
666 -- Get_Kind --
667 --------------
670 begin
673 else
678 -- Start of processing for Build_Access_Subprogram_Type
680 begin
681 -- In the case of an access to subprogram, use the name of the
682 -- subprogram itself as the designated type. Type-checking in
683 -- this case compares the signatures of the designated types.
685 -- Note: This fragment of the tree is temporarily malformed
686 -- because the correct tree requires an E_Subprogram_Type entity
687 -- as the designated type. In most cases this designated type is
688 -- later overridden by the semantics with the type imposed by the
689 -- context during the resolution phase. In the specific case of
690 -- the expression Address!(Prim'Unrestricted_Access), used to
691 -- initialize slots of dispatch tables, this work will be done by
692 -- the expander (see Exp_Aggr).
694 -- The reason to temporarily add this kind of node to the tree
695 -- instead of a proper E_Subprogram_Type itype, is the following:
696 -- in case of errors found in the source file we report better
697 -- error messages. For example, instead of generating the
698 -- following error:
700 -- "expected access to subprogram with profile
701 -- defined at line X"
703 -- we currently generate:
705 -- "expected access to function Z defined at line X"
722 else
741 -- Cannot be applied to intrinsic. Looking at the tests above,
742 -- the only way Etype (N) can still be set to Any_Type is if
743 -- Is_Intrinsic_Subprogram was True for some referenced entity.
750 ----------------------
751 -- OK_Self_Reference --
752 ----------------------
757 begin
760 and then
763 loop
768 -- Check the context: the aggregate must be part of the
769 -- initialization of a type or component, or it is the
770 -- resulting expansion in an initialization procedure.
774 else
792 -- No enclosing aggregate, or not a self-reference
797 -- Start of processing for Analyze_Access_Attribute
799 begin
800 Check_SPARK_05_Restriction_On_Attribute;
801 Check_E0;
804 Error_Attr_P
808 -- Preserve relevant elaboration-related attributes of the context
809 -- which are no longer available or very expensive to recompute once
810 -- analysis, resolution, and expansion are over.
812 Mark_Elaboration_Attributes
817 -- Save the scenario for later examination by the ABE Processing
818 -- phase.
822 -- Case of access to subprogram
826 Error_Attr_P
833 -- Issue an error if the prefix denotes an eliminated subprogram
837 -- Check for obsolescent subprogram reference
841 -- Build the appropriate subprogram type
845 -- For P'Access or P'Unrestricted_Access, where P is a nested
846 -- subprogram, we might be passing P to another subprogram (but we
847 -- don't check that here), which might call P. P could modify
848 -- local variables, so we need to kill current values. It is
849 -- important not to do this for library-level subprograms, because
850 -- Kill_Current_Values is very inefficient in the case of library
851 -- level packages with lots of tagged types.
856 -- Do not kill values on nodes initializing dispatch tables
857 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
858 -- is currently generated by the expander only for this
859 -- purpose. Done to keep the quality of warnings currently
860 -- generated by the compiler (otherwise any declaration of
861 -- a tagged type cleans constant indications from its scope).
865 or else
867 and then Is_Dispatching_Operation
869 then
872 else
873 Kill_Current_Values;
878 -- Component is an operation of a protected type
882 then
891 -- Deal with incorrect reference to a type, but note that some
892 -- accesses are allowed: references to the current type instance,
893 -- or in Ada 2005 self-referential pointer in a default-initialized
894 -- aggregate.
899 -- The reference may appear in an aggregate that has been expanded
900 -- into a loop. Locate scope of type definition, if any.
909 -- OK if we are within the scope of a limited type
910 -- let's mark the component as having per object constraint
919 declare
922 begin
925 loop
930 Set_Has_Per_Object_Constraint
936 Error_Msg_F
940 -- If a current instance attribute appears in a component
941 -- constraint it must appear alone; other contexts (spec-
942 -- expressions, within a task body) are not subject to this
943 -- restriction.
945 if not In_Spec_Expression
947 and then not
949 N_Index_Or_Discriminant_Constraint)
950 then
951 Error_Msg_N
956 Error_Msg_N
961 -- OK if we are in initialization procedure for the type
962 -- in question, in which case the reference to the type
963 -- is rewritten as a reference to the current object.
968 then
976 -- OK if a task type, this test needs sharpening up ???
981 -- OK if self-reference in an aggregate in Ada 2005, and
982 -- the reference comes from a copied default expression.
984 -- Note that we check legality of self-reference even if the
985 -- expression comes from source, e.g. when a single component
986 -- association in an aggregate has a box association.
989 and then OK_Self_Reference
990 then
993 -- OK if reference to current instance of a protected object
998 -- Otherwise we have an error case
1000 else
1007 -- If we fall through, we have a normal access to object case
1009 -- Unrestricted_Access is (for now) legal wherever an allocator would
1010 -- be legal, so its Etype is set to E_Allocator. The expected type
1011 -- of the other attributes is a general access type, and therefore
1012 -- we label them with E_Access_Attribute_Type.
1018 else
1019 declare
1022 begin
1033 -- Special cases when we can find a prefix that is an entity name
1035 declare
1039 begin
1041 loop
1045 -- If we have an access to an object, and the attribute
1046 -- comes from source, then set the object as potentially
1047 -- source modified. We do this because the resulting access
1048 -- pointer can be used to modify the variable, and we might
1049 -- not detect this, leading to some junk warnings.
1051 -- We only do this for source references, since otherwise
1052 -- we can suppress warnings, e.g. from the unrestricted
1053 -- access generated for validity checks in -gnatVa mode.
1059 -- Mark entity as address taken in the case of
1060 -- 'Unrestricted_Access or subprograms, and kill current
1061 -- values.
1065 then
1073 N_Indexed_Component)
1074 then
1077 else
1084 ----------------------------------
1085 -- Analyze_Attribute_Old_Result --
1086 ----------------------------------
1088 procedure Analyze_Attribute_Old_Result
1091 is
1093 -- Verify that the attribute appears within pragma Check that mimics
1094 -- a postcondition.
1097 -- Verify that the attribute appears within a consequence of aspect
1098 -- or pragma Contract_Cases denoted by Prag.
1101 -- Verify that the attribute appears within the "Ensures" argument of
1102 -- aspect or pragma Test_Case denoted by Prag.
1104 function Is_Within
1107 -- Subsidiary to Check_Placemenet_In_XXX. Determine whether arbitrary
1108 -- node Nod is within enclosing node Encl_Nod.
1111 -- Emit a general error when the attributes does not appear in a
1112 -- postcondition-like aspect or pragma.
1114 ------------------------------
1115 -- Check_Placement_In_Check --
1116 ------------------------------
1122 begin
1123 -- The "Name" argument of pragma Check denotes a postcondition
1126 Name_Post_Class,
1127 Name_Postcondition,
1128 Name_Refined_Post)
1129 then
1132 -- Otherwise the placement of the attribute is illegal
1134 else
1135 Placement_Error;
1139 ---------------------------------------
1140 -- Check_Placement_In_Contract_Cases --
1141 ---------------------------------------
1148 begin
1149 -- Obtain the argument of the aspect or pragma
1153 else
1163 -- Detect whether the attribute appears within the
1164 -- consequence of the current contract case.
1168 then
1176 -- Otherwise aspect or pragma Contract_Cases is either malformed
1177 -- or the attribute does not appear within a consequence.
1179 Error_Attr
1181 P);
1184 ----------------------------------
1185 -- Check_Placement_In_Test_Case --
1186 ----------------------------------
1190 Test_Case_Arg
1195 begin
1196 -- Detect whether the attribute appears within the "Ensures"
1197 -- expression of aspect or pragma Test_Case.
1202 else
1203 Error_Attr
1209 ---------------
1210 -- Is_Within --
1211 ---------------
1213 function Is_Within
1216 is
1219 begin
1225 -- Prevent the search from going too far
1237 ---------------------
1238 -- Placement_Error --
1239 ---------------------
1242 begin
1246 -- Specialize the error message for attribute 'Result
1248 else
1249 Error_Attr
1251 P);
1255 -- Local variables
1261 -- Start of processing for Analyze_Attribute_Old_Result
1263 begin
1264 -- Assume that the attribute is illegal
1269 -- Traverse the parent chain to find the aspect or pragma where the
1270 -- attribute resides.
1277 -- Prevent the search from going too far
1286 -- The attribute is allowed to appear only in postcondition-like
1287 -- aspects or pragmas.
1292 else
1302 -- Attribute 'Result is allowed to appear in aspect or pragma
1303 -- [Refined_]Depends (SPARK RM 6.1.5(11)).
1307 then
1311 Name_Post_Class,
1312 Name_Postcondition,
1313 Name_Refined_Post)
1314 then
1320 else
1321 Placement_Error;
1325 -- Otherwise the placement of the attribute is illegal
1327 else
1328 Placement_Error;
1332 -- Find the related subprogram subject to the aspect or pragma
1336 else
1340 -- The aspect or pragma where the attribute resides should be
1341 -- associated with a subprogram declaration or a body. If this is not
1342 -- the case, then the aspect or pragma is illegal. Return as analysis
1343 -- cannot be carried out. Note that it is legal to have the aspect
1344 -- appear on a subprogram renaming, when the renamed entity is an
1345 -- attribute reference.
1347 -- Generating C code the internally built nested _postcondition
1348 -- subprograms are inlined; after expanded, inlined aspects are
1349 -- located in the internal block generated by the frontend.
1352 and then Modify_Tree_For_C
1353 and then In_Inlined_Body
1354 then
1358 N_Entry_Declaration,
1359 N_Expression_Function,
1360 N_Generic_Subprogram_Declaration,
1361 N_Subprogram_Body,
1362 N_Subprogram_Body_Stub,
1363 N_Subprogram_Declaration,
1364 N_Subprogram_Renaming_Declaration)
1365 then
1369 -- If we get here, then the attribute is legal
1374 -- When generating C code, nested _postcondition subprograms are
1375 -- inlined by the front end to avoid problems (when unnested) with
1376 -- referenced itypes. Handle that here, since as part of inlining the
1377 -- expander nests subprogram within a dummy procedure named _parent
1378 -- (see Build_Postconditions_Procedure and Build_Body_To_Inline).
1379 -- Hence, in this context, the spec_id of _postconditions is the
1380 -- enclosing scope.
1382 if Modify_Tree_For_C
1385 then
1386 -- This situation occurs only when preanalyzing the inlined body
1395 -----------------------------
1396 -- Analyze_Image_Attribute --
1397 -----------------------------
1400 begin
1401 Check_SPARK_05_Restriction_On_Attribute;
1403 -- AI12-00124: The ARG has adopted the GNAT semantics of 'Img for
1404 -- scalar types, so that the prefix can be an object, a named value,
1405 -- or a type, and there is no need for an argument in this case.
1409 then
1410 Check_E0;
1414 Error_Attr_P
1417 else
1418 Check_E1;
1421 -- Check that the prefix type is scalar - much in the same way as
1422 -- Check_Scalar_Type but with custom error messages to denote the
1423 -- variants of 'Image attributes.
1429 then
1437 then
1439 Error_Attr_P
1442 else
1447 Error_Attr_P
1453 Validate_Non_Static_Attribute_Function_Call;
1456 Check_Enum_Image;
1458 -- Check restriction No_Fixed_IO. Note the check of Comes_From_Source
1459 -- to avoid giving a duplicate message for when Image attributes
1460 -- applied to object references get expanded into type-based Image
1461 -- attributes.
1466 then
1471 ---------------------------------
1472 -- Bad_Attribute_For_Predicate --
1473 ---------------------------------
1476 begin
1479 then
1481 Bad_Predicated_Subtype_Use
1486 --------------------------------
1487 -- Check_Array_Or_Scalar_Type --
1488 --------------------------------
1492 -- A current instance of a type in an aspect specification is an
1493 -- object and not a type, and therefore cannot be of a scalar type
1494 -- in the prefix of one of the array attributes if the attribute
1495 -- reference is part of an aspect expression.
1497 -----------------------------
1498 -- In_Aspect_Specification --
1499 -----------------------------
1504 begin
1520 -- Local variables
1525 -- Start of processing for Check_Array_Or_Scalar_Type
1527 begin
1528 -- Case of string literal or string literal subtype. These cases
1529 -- cannot arise from legal Ada code, but the expander is allowed
1530 -- to generate them. They require special handling because string
1531 -- literal subtypes do not have standard bounds (the whole idea
1532 -- of these subtypes is to avoid having to generate the bounds)
1538 -- Scalar types
1541 Check_Type;
1547 Error_Attr
1551 else
1556 -- The following is a special test to allow 'First to apply to
1557 -- private scalar types if the attribute comes from generated
1558 -- code. This occurs in the case of Normalize_Scalars code.
1564 then
1567 -- Array types other than string literal subtypes handled above
1569 else
1570 Check_Array_Type;
1572 -- We know prefix is an array type, or the name of an array
1573 -- object, and that the expression, if present, is static
1574 -- and within the range of the dimensions of the type.
1581 -- First dimension assumed
1585 else
1598 ----------------------
1599 -- Check_Array_Type --
1600 ----------------------
1604 -- Dimension number for array attributes
1606 begin
1607 -- If the type is a string literal type, then this must be generated
1608 -- internally, and no further check is required on its legality.
1613 -- If the type is a composite, it is an illegal aggregate, no point
1614 -- in going on.
1620 -- Normal case of array type or subtype
1622 Check_Either_E0_Or_E1;
1623 Check_Dereference;
1629 then
1630 -- Note: we do not call Error_Attr here, since we prefer to
1631 -- continue, using the relevant index type of the array,
1632 -- even though it is unconstrained. This gives better error
1633 -- recovery behavior.
1636 Error_Msg_F
1640 -- The attribute reference freezes the type, and thus the
1641 -- component type, even if the attribute may not depend on the
1642 -- component. Diagnose arrays with incomplete components now.
1643 -- If the prefix is an access to array, this does not freeze
1644 -- the designated type.
1652 else
1660 then
1664 or else
1665 Attr_Id = Attribute_Last
1666 then
1669 else
1680 then
1681 Flag_Non_Static_Expr
1683 Error_Attr;
1687 then
1694 then
1699 -------------------------
1700 -- Check_Asm_Attribute --
1701 -------------------------
1704 begin
1705 Check_Type;
1706 Check_E2;
1708 -- Check first argument is static string expression
1716 Flag_Non_Static_Expr
1718 Error_Attr;
1721 -- Check second argument is right type
1725 -- Note: that is all we need to do, we don't need to check
1726 -- that it appears in a correct context. The Ada type system
1727 -- will do that for us.
1731 ---------------------
1732 -- Check_Component --
1733 ---------------------
1736 begin
1737 Check_E0;
1740 or else
1742 and then
1744 then
1749 ------------------------------------
1750 -- Check_Decimal_Fixed_Point_Type --
1751 ------------------------------------
1754 begin
1755 Check_Type;
1762 -----------------------
1763 -- Check_Dereference --
1764 -----------------------
1767 begin
1769 -- Case of a subtype mark
1775 -- Case of an expression
1781 -- If there is an implicit dereference, then we must freeze the
1782 -- designated type of the access type, since the type of the
1783 -- referenced array is this type (see AI95-00106).
1785 -- As done elsewhere, freezing must not happen when pre-analyzing
1786 -- a pre- or postcondition or a default value for an object or for
1787 -- a formal parameter.
1808 -------------------------
1809 -- Check_Discrete_Type --
1810 -------------------------
1813 begin
1814 Check_Type;
1821 --------------
1822 -- Check_E0 --
1823 --------------
1826 begin
1832 --------------
1833 -- Check_E1 --
1834 --------------
1837 begin
1838 Check_Either_E0_Or_E1;
1842 -- Special-case attributes that are functions and that appear as
1843 -- the prefix of another attribute. Error is posted on parent.
1847 Name_Code_Address,
1848 Name_Access)
1849 then
1856 else
1862 --------------
1863 -- Check_E2 --
1864 --------------
1867 begin
1875 ---------------------------
1876 -- Check_Either_E0_Or_E1 --
1877 ---------------------------
1880 begin
1886 ----------------------
1887 -- Check_Enum_Image --
1888 ----------------------
1893 begin
1894 -- When an enumeration type appears in an attribute reference, all
1895 -- literals of the type are marked as referenced. This must only be
1896 -- done if the attribute reference appears in the current source.
1897 -- Otherwise the information on references may differ between a
1898 -- normal compilation and one that performs inlining.
1902 then
1911 ----------------------------
1912 -- Check_First_Last_Valid --
1913 ----------------------------
1916 begin
1917 Check_Discrete_Type;
1919 -- Freeze the subtype now, so that the following test for predicates
1920 -- works (we set the predicates stuff up at freeze time)
1924 -- Now test for dynamic predicate
1928 then
1929 Error_Attr_P
1933 -- Check non-static subtype
1939 -- Test case for no values
1944 and then
1946 then
1947 Error_Attr_P
1953 ----------------------------
1954 -- Check_Fixed_Point_Type --
1955 ----------------------------
1958 begin
1959 Check_Type;
1966 ------------------------------
1967 -- Check_Fixed_Point_Type_0 --
1968 ------------------------------
1971 begin
1972 Check_Fixed_Point_Type;
1973 Check_E0;
1976 -------------------------------
1977 -- Check_Floating_Point_Type --
1978 -------------------------------
1981 begin
1982 Check_Type;
1989 ---------------------------------
1990 -- Check_Floating_Point_Type_0 --
1991 ---------------------------------
1994 begin
1995 Check_Floating_Point_Type;
1996 Check_E0;
1999 ---------------------------------
2000 -- Check_Floating_Point_Type_1 --
2001 ---------------------------------
2004 begin
2005 Check_Floating_Point_Type;
2006 Check_E1;
2009 ---------------------------------
2010 -- Check_Floating_Point_Type_2 --
2011 ---------------------------------
2014 begin
2015 Check_Floating_Point_Type;
2016 Check_E2;
2019 ------------------------
2020 -- Check_Integer_Type --
2021 ------------------------
2024 begin
2025 Check_Type;
2032 --------------------------------
2033 -- Check_Modular_Integer_Type --
2034 --------------------------------
2037 begin
2038 Check_Type;
2041 Error_Attr_P
2046 ------------------------
2047 -- Check_Not_CPP_Type --
2048 ------------------------
2051 begin
2055 then
2056 Error_Attr_P
2061 -------------------------------
2062 -- Check_Not_Incomplete_Type --
2063 -------------------------------
2069 begin
2070 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
2071 -- dereference we have to check wrong uses of incomplete types
2072 -- (other wrong uses are checked at their freezing point).
2074 -- In Ada 2012, incomplete types can appear in subprogram
2075 -- profiles, but formals with incomplete types cannot be the
2076 -- prefix of attributes.
2078 -- Example 1: Limited-with
2080 -- limited with Pkg;
2081 -- package P is
2082 -- type Acc is access Pkg.T;
2083 -- X : Acc;
2084 -- S : Integer := X.all'Size; -- ERROR
2085 -- end P;
2087 -- Example 2: Tagged incomplete
2089 -- type T is tagged;
2090 -- type Acc is access all T;
2091 -- X : Acc;
2092 -- S : constant Integer := X.all'Size; -- ERROR
2093 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
2097 then
2106 Error_Attr_P
2109 -- If the prefix is an access type check the designated type
2113 then
2121 -- A legal use of a shadow entity occurs only when the unit where
2122 -- the non-limited view resides is imported via a regular with
2123 -- clause in the current body. Such references to shadow entities
2124 -- may occur in subprogram formals.
2130 then
2134 -- If still incomplete, it can be a local incomplete type, or a
2135 -- limited view whose scope is also a limited view.
2140 then
2141 Error_Attr_P
2144 -- The limited view may be available indirectly through
2145 -- an intermediate unit. If the non-limited view is available
2146 -- the attribute reference is legal.
2149 and then
2152 then
2153 Error_Attr_P
2158 -- Ada 2012 : formals in bodies may be incomplete, but no attribute
2159 -- legally applies.
2164 then
2165 Error_Attr_P
2171 or else In_Spec_Expression
2172 then
2174 else
2179 ----------------------------
2180 -- Check_Object_Reference --
2181 ----------------------------
2186 begin
2187 -- If we need an object, and we have a prefix that is the name of
2188 -- a function entity, convert it into a function call.
2192 then
2201 -- Otherwise we must have an object reference
2208 ----------------------------
2209 -- Check_PolyORB_Attribute --
2210 ----------------------------
2213 begin
2214 Validate_Non_Static_Attribute_Function_Call;
2216 Check_Type;
2217 Check_Not_CPP_Type;
2220 Error_Attr
2225 ------------------------
2226 -- Check_Program_Unit --
2227 ------------------------
2230 begin
2232 declare
2236 begin
2243 and then
2245 or else
2247 then
2256 ---------------------
2257 -- Check_Real_Type --
2258 ---------------------
2261 begin
2262 Check_Type;
2269 -----------------------
2270 -- Check_Scalar_Type --
2271 -----------------------
2274 begin
2275 Check_Type;
2282 ------------------------------------------
2283 -- Check_SPARK_05_Restriction_On_Attribute --
2284 ------------------------------------------
2287 begin
2292 ---------------------------
2293 -- Check_Standard_Prefix --
2294 ---------------------------
2297 begin
2298 Check_E0;
2305 ----------------------------
2306 -- Check_Stream_Attribute --
2307 ----------------------------
2314 -- True when compiling System.Shared_Storage.Shared_Var_Procs body.
2315 -- For this runtime package (always compiled in GNAT mode), we allow
2316 -- stream attributes references for limited types for the case where
2317 -- shared passive objects are implemented using stream attributes,
2318 -- which is the default in GNAT's persistent storage implementation.
2320 begin
2321 Validate_Non_Static_Attribute_Function_Call;
2323 -- With the exception of 'Input, Stream attributes are procedures,
2324 -- and can only appear at the position of procedure calls. We check
2325 -- for this here, before they are rewritten, to give a more precise
2326 -- diagnostic.
2333 N_Aggregate)
2334 then
2337 else
2338 Error_Attr
2342 Check_Type;
2345 -- Stream attributes not allowed on limited types unless the
2346 -- attribute reference was generated by the expander (in which
2347 -- case the underlying type will be used, as described in Sinfo),
2348 -- or the attribute was specified explicitly for the type itself
2349 -- or one of its ancestors (taking visibility rules into account if
2350 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
2351 -- (with no visibility restriction).
2353 declare
2355 begin
2357 In_Shared_Var_Procs :=
2359 else
2368 then
2372 Error_Msg_NE
2375 else
2376 Error_Msg_NE
2381 -- Check for no stream operations allowed from No_Tagged_Streams
2385 then
2387 Error_Msg_NE
2392 -- Check restriction violations
2394 -- First check the No_Streams restriction, which prohibits the use
2395 -- of explicit stream attributes in the source program. We do not
2396 -- prevent the occurrence of stream attributes in generated code,
2397 -- for instance those generated implicitly for dispatching purposes.
2403 -- AI05-0057: if restriction No_Default_Stream_Attributes is active,
2404 -- it is illegal to use a predefined elementary type stream attribute
2405 -- either by itself, or more importantly as part of the attribute
2406 -- subprogram for a composite type. However, if the broader
2407 -- restriction No_Streams is active, stream operations are not
2408 -- generated, and there is no error.
2412 then
2413 declare
2416 begin
2418 or else
2419 Nam = TSS_Stream_Read
2420 then
2421 T :=
2423 else
2424 T :=
2431 Error_Msg_NE
2435 Error_Msg_NE
2442 -- Check special case of Exception_Id and Exception_Occurrence which
2443 -- are not allowed for restriction No_Exception_Registration.
2447 or else
2449 then
2453 -- Here we must check that the first argument is an access type
2454 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
2459 -- Note: the double call to Root_Type here is needed because the
2460 -- root type of a class-wide type is the corresponding type (e.g.
2461 -- X for X'Class, and we really want to go to the root.)
2466 then
2467 Error_Attr
2471 -- Check that the second argument is of the right type if there is
2472 -- one (the Input attribute has only one argument so this is skipped)
2479 then
2480 Error_Attr
2487 Check_Not_CPP_Type;
2490 -------------------------
2491 -- Check_System_Prefix --
2492 -------------------------
2495 begin
2501 -----------------------
2502 -- Check_Task_Prefix --
2503 -----------------------
2506 begin
2509 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
2510 -- task interface class-wide types.
2519 then
2522 else
2524 Error_Attr_P
2528 else
2534 ----------------
2535 -- Check_Type --
2536 ----------------
2538 -- The possibilities are an entity name denoting a type, or an
2539 -- attribute reference that denotes a type (Base or Class). If
2540 -- the type is incomplete, replace it with its full view.
2543 begin
2546 then
2550 Error_Attr_P
2556 then
2562 ---------------------
2563 -- Check_Unit_Name --
2564 ---------------------
2567 begin
2582 ----------------
2583 -- Error_Attr --
2584 ----------------
2587 begin
2594 begin
2597 Error_Attr;
2600 ------------------
2601 -- Error_Attr_P --
2602 ------------------
2605 begin
2608 Error_Attr;
2611 ----------------------------
2612 -- Legal_Formal_Attribute --
2613 ----------------------------
2616 begin
2617 Check_E0;
2621 then
2625 or else In_Instance
2626 or else In_Inlined_Body
2627 then
2632 Error_Attr_P
2636 else
2637 Error_Attr_P
2644 ---------------------------------------------------------------
2645 -- Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements --
2646 ---------------------------------------------------------------
2649 begin
2650 Check_E0;
2651 Check_Type;
2652 Check_Not_Incomplete_Type;
2656 -------------
2657 -- Min_Max --
2658 -------------
2661 begin
2662 Check_E2;
2663 Check_Scalar_Type;
2668 -- Check for comparison on unordered enumeration type
2672 Error_Msg_NE
2678 ------------------------
2679 -- Standard_Attribute --
2680 ------------------------
2683 begin
2684 Check_Standard_Prefix;
2690 --------------------
2691 -- Uneval_Old_Msg --
2692 --------------------
2698 begin
2699 -- If from aspect, then Uneval_Old_Setting comes from flags in the
2700 -- N_Aspect_Specification node that corresponds to the attribute.
2702 -- First find the pragma in which we appear (note that at this stage,
2703 -- even if we appeared originally within an aspect specification, we
2704 -- are now within the corresponding pragma).
2707 loop
2717 else
2721 -- If we did not find the pragma, that's odd, just use the setting
2722 -- from Opt.Uneval_Old. Perhaps this is due to a previous error?
2724 else
2728 -- Processing depends on the setting of Uneval_Old
2732 Error_Attr_P
2738 Error_Msg_F
2750 -------------------------
2751 -- Unexpected Argument --
2752 -------------------------
2755 begin
2759 -------------------------------------------------
2760 -- Validate_Non_Static_Attribute_Function_Call --
2761 -------------------------------------------------
2763 -- This function should be moved to Sem_Dist ???
2766 begin
2767 if In_Preelaborated_Unit
2768 and then not In_Subprogram_Or_Concurrent_Unit
2769 then
2770 Flag_Non_Static_Expr
2775 -- Start of processing for Analyze_Attribute
2777 begin
2778 -- Immediate return if unrecognized attribute (already diagnosed by
2779 -- parser, so there is nothing more that we need to do).
2787 -- Deal with Ada 83 issues
2802 -- Deal with Ada 2005 attributes that are implementation attributes
2803 -- because they appear in a version of Ada before Ada 2005, and
2804 -- similarly for Ada 2012 attributes appearing in an earlier version.
2807 or else
2809 then
2813 -- Remote access to subprogram type access attribute reference needs
2814 -- unanalyzed copy for tree transformation. The analyzed copy is used
2815 -- for its semantic information (whether prefix is a remote subprogram
2816 -- name), the unanalyzed copy is used to construct new subtree rooted
2817 -- with N_Aggregate which represents a fat pointer aggregate.
2823 -- Analyze prefix and exit if error in analysis. If the prefix is an
2824 -- incomplete type, use full view if available. Note that there are
2825 -- some attributes for which we do not analyze the prefix, since the
2826 -- prefix is not a normal name, or else needs special handling.
2832 Aname /= Name_Old
2833 then
2840 then
2848 then
2849 -- Use of current instance within the type. Verify that if the
2850 -- attribute appears within a constraint, it yields an access
2851 -- type, other uses are illegal.
2853 declare
2856 begin
2860 loop
2866 then
2870 then
2871 Error_Msg_N
2887 -- Analyze expressions that may be present, exiting if an error occurs
2893 else
2896 -- Skip analysis for case of Restriction_Set, we do not expect
2897 -- the argument to be analyzed in this case.
2902 -- Check for missing/bad expression (result of previous error)
2924 -- Cases where prefix must be resolvable by itself
2932 then
2933 -- The prefix must be resolvable by itself, without reference to the
2934 -- attribute. One case that requires special handling is a prefix
2935 -- that is a function name, where one interpretation may be a
2936 -- parameterless call. Entry attributes are handled specially below.
2940 then
2946 -- Ada 2005 (AI-345): Since protected and task types have
2947 -- primitive entry wrappers, the attributes Count, and Caller
2948 -- require a context check
2951 declare
2956 begin
2961 else
2970 else
2975 else
2981 -- In SPARK, attributes of private types are only allowed if the full
2982 -- type declaration is visible.
2984 -- Note: the check for Present (Entity (P)) defends against some error
2985 -- conditions where the Entity field is not set.
2991 and then not In_Spec_Expression
2992 then
2996 -- Remaining processing depends on attribute
3000 -- Attributes related to Ada 2012 iterators. Attribute specifications
3001 -- exist for these, but they cannot be queried.
3003 when Attribute_Constant_Indexing
3004 | Attribute_Default_Iterator
3005 | Attribute_Implicit_Dereference
3006 | Attribute_Iterator_Element
3007 | Attribute_Iterable
3008 | Attribute_Variable_Indexing
3009 =>
3012 -- Internal attributes used to deal with Ada 2012 delayed aspects. These
3013 -- were already rejected by the parser. Thus they shouldn't appear here.
3018 ------------------
3019 -- Abort_Signal --
3020 ------------------
3023 Check_Standard_Prefix;
3027 ------------
3028 -- Access --
3029 ------------
3032 Analyze_Access_Attribute;
3033 Check_Not_Incomplete_Type;
3035 -------------
3036 -- Address --
3037 -------------
3040 Check_E0;
3041 Address_Checks;
3042 Check_Not_Incomplete_Type;
3045 ------------------
3046 -- Address_Size --
3047 ------------------
3052 --------------
3053 -- Adjacent --
3054 --------------
3057 Check_Floating_Point_Type_2;
3062 ---------
3063 -- Aft --
3064 ---------
3067 Check_Fixed_Point_Type_0;
3070 ---------------
3071 -- Alignment --
3072 ---------------
3076 -- Don't we need more checking here, cf Size ???
3078 Check_E0;
3079 Check_Not_Incomplete_Type;
3080 Check_Not_CPP_Type;
3083 ---------------
3084 -- Asm_Input --
3085 ---------------
3088 Check_Asm_Attribute;
3090 -- The back end may need to take the address of E2
3098 ----------------
3099 -- Asm_Output --
3100 ----------------
3103 Check_Asm_Attribute;
3110 Error_Attr
3117 -- The back end may need to take the address of E2
3125 -----------------------------
3126 -- Atomic_Always_Lock_Free --
3127 -----------------------------
3130 Check_E0;
3131 Check_Type;
3134 ----------
3135 -- Base --
3136 ----------
3138 -- Note: when the base attribute appears in the context of a subtype
3139 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
3140 -- the following circuit.
3145 begin
3146 Check_E0;
3153 then
3158 and then Warn_On_Redundant_Constructs
3159 then
3160 Error_Msg_NE -- CODEFIX
3166 Check_SPARK_05_Restriction
3176 ---------
3177 -- Bit --
3178 ---------
3181 Check_E0;
3186 -- What about the access object cases ???
3188 else
3194 ---------------
3195 -- Bit_Order --
3196 ---------------
3199 Check_E0;
3200 Check_Type;
3209 else
3217 -- Reset incorrect indication of staticness
3221 ------------------
3222 -- Bit_Position --
3223 ------------------
3225 -- Note: in generated code, we can have a Bit_Position attribute
3226 -- applied to a (naked) record component (i.e. the prefix is an
3227 -- identifier that references an E_Component or E_Discriminant
3228 -- entity directly, and this is interpreted as expected by Gigi.
3229 -- The following code will not tolerate such usage, but when the
3230 -- expander creates this special case, it marks it as analyzed
3231 -- immediately and sets an appropriate type.
3235 Check_Component;
3240 ------------------
3241 -- Body_Version --
3242 ------------------
3245 Check_E0;
3246 Check_Program_Unit;
3249 --------------
3250 -- Callable --
3251 --------------
3254 Check_E0;
3256 Check_Task_Prefix;
3258 ------------
3259 -- Caller --
3260 ------------
3266 begin
3267 Check_E0;
3276 else
3294 -------------
3295 -- Ceiling --
3296 -------------
3299 Check_Floating_Point_Type_1;
3303 -----------
3304 -- Class --
3305 -----------
3309 Check_E0;
3312 -- Applying Class to untagged incomplete type is obsolescent in Ada
3313 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
3314 -- this flag gets set by Find_Type in this situation.
3319 then
3320 declare
3322 begin
3325 then
3331 ------------------
3332 -- Code_Address --
3333 ------------------
3336 Check_E0;
3340 then
3345 and then
3347 then
3351 -- Issue an error if the prefix denotes an eliminated subprogram
3353 else
3359 ----------------------
3360 -- Compiler_Version --
3361 ----------------------
3364 Check_E0;
3365 Check_Standard_Prefix;
3370 --------------------
3371 -- Component_Size --
3372 --------------------
3375 Check_E0;
3378 -- Note: unlike other array attributes, unconstrained arrays are OK
3382 else
3383 Check_Array_Type;
3386 -------------
3387 -- Compose --
3388 -------------
3391 Check_Floating_Point_Type_2;
3396 -----------------
3397 -- Constrained --
3398 -----------------
3401 Check_E0;
3404 -- Case from RM J.4(2) of constrained applied to private type
3410 Error_Msg_N
3415 -- If we are within an instance, the attribute must be legal
3416 -- because it was valid in the generic unit. Ditto if this is
3417 -- an inlining of a function declared in an instance.
3422 -- For sure OK if we have a real private type itself, but must
3423 -- be completed, cannot apply Constrained to incomplete type.
3427 -- Note: this is one of the Annex J features that does not
3428 -- generate a warning from -gnatwj, since in fact it seems
3429 -- very useful, and is used in the GNAT runtime.
3431 Check_Not_Incomplete_Type;
3435 -- Normal (non-obsolescent case) of application to object of
3436 -- a discriminated type.
3438 else
3441 -- If N does not come from source, then we allow the
3442 -- the attribute prefix to be of a private type whose
3443 -- full type has discriminants. This occurs in cases
3444 -- involving expanded calls to stream attributes.
3450 -- Must have discriminants or be an access type designating a type
3451 -- with discriminants. If it is a class-wide type it has unknown
3452 -- discriminants.
3456 or else
3459 then
3462 -- The rule given in 3.7.2 is part of static semantics, but the
3463 -- intent is clearly that it be treated as a legality rule, and
3464 -- rechecked in the visible part of an instance. Nevertheless
3465 -- the intent also seems to be it should legally apply to the
3466 -- actual of a formal with unknown discriminants, regardless of
3467 -- whether the actual has discriminants, in which case the value
3468 -- of the attribute is determined using the J.4 rules. This choice
3469 -- seems the most useful, and is compatible with existing tests.
3474 -- Also allow an object of a generic type if extensions allowed
3475 -- and allow this for any type at all. (this may be obsolete ???)
3479 and then Extensions_Allowed
3480 then
3485 -- Fall through if bad prefix
3487 Error_Attr_P
3490 ---------------
3491 -- Copy_Sign --
3492 ---------------
3495 Check_Floating_Point_Type_2;
3500 -----------
3501 -- Count --
3502 -----------
3509 begin
3510 Check_E0;
3523 then
3527 E_Entry_Family
3528 then
3529 Error_Attr
3532 else
3537 else
3544 then
3545 Error_Attr
3548 else
3560 -- The prefix denotes either the task type, or else a
3561 -- single task whose task type is being analyzed.
3567 then
3569 else
3570 Error_Attr
3579 E_Entry,
3580 E_Entry_Family,
3581 E_Loop)
3582 then
3587 then
3593 declare
3597 begin
3603 -- Ada 2005 (AI-345): Do not consider primitive entry
3604 -- wrappers generated for task or protected types.
3608 then
3611 else
3623 -----------------------
3624 -- Default_Bit_Order --
3625 -----------------------
3630 begin
3631 Check_Standard_Prefix;
3635 else
3647 ----------------------------------
3648 -- Default_Scalar_Storage_Order --
3649 ----------------------------------
3654 begin
3655 Check_Standard_Prefix;
3661 else
3678 --------------
3679 -- Definite --
3680 --------------
3683 Legal_Formal_Attribute;
3685 -----------
3686 -- Delta --
3687 -----------
3690 Check_Fixed_Point_Type_0;
3693 ------------
3694 -- Denorm --
3695 ------------
3698 Check_Floating_Point_Type_0;
3701 -----------
3702 -- Deref --
3703 -----------
3706 Check_Type;
3707 Check_E1;
3711 ---------------------
3712 -- Descriptor_Size --
3713 ---------------------
3716 Check_E0;
3724 ------------
3725 -- Digits --
3726 ------------
3729 Check_E0;
3730 Check_Type;
3734 then
3735 Error_Attr_P
3741 ---------------
3742 -- Elab_Body --
3743 ---------------
3745 -- Also handles processing for Elab_Spec and Elab_Subp_Body
3747 when Attribute_Elab_Body
3748 | Attribute_Elab_Spec
3749 | Attribute_Elab_Subp_Body
3750 =>
3751 Check_E0;
3755 -- We have to manually call the expander in this case to get
3756 -- the necessary expansion (normally attributes that return
3757 -- entities are not expanded).
3761 ---------------
3762 -- Elab_Spec --
3763 ---------------
3765 -- Shares processing with Elab_Body
3767 ----------------
3768 -- Elaborated --
3769 ----------------
3772 Check_E0;
3776 ----------
3777 -- Emax --
3778 ----------
3781 Check_Floating_Point_Type_0;
3784 -------------
3785 -- Enabled --
3786 -------------
3789 Check_Either_E0_Or_E1;
3806 --------------
3807 -- Enum_Rep --
3808 --------------
3812 -- T'Enum_Rep (X) case
3815 Check_E1;
3816 Check_Discrete_Type;
3819 -- X'Enum_Rep case. X must be an object or enumeration literal, and
3820 -- it must be of a discrete type.
3822 elsif not
3824 or else
3828 then
3834 --------------
3835 -- Enum_Val --
3836 --------------
3839 Check_E1;
3840 Check_Type;
3846 -- If the enumeration type has a standard representation, the effect
3847 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3857 -- Non-standard representation case (enumeration with holes)
3859 else
3860 Check_Enum_Image;
3865 -------------
3866 -- Epsilon --
3867 -------------
3870 Check_Floating_Point_Type_0;
3873 --------------
3874 -- Exponent --
3875 --------------
3878 Check_Floating_Point_Type_1;
3882 ------------------
3883 -- External_Tag --
3884 ------------------
3887 Check_E0;
3888 Check_Type;
3896 ---------------
3897 -- Fast_Math --
3898 ---------------
3901 Check_Standard_Prefix;
3904 -----------------------
3905 -- Finalization_Size --
3906 -----------------------
3909 Check_E0;
3911 -- The prefix denotes an object
3916 -- The prefix denotes a type
3919 Check_Type;
3920 Check_Not_Incomplete_Type;
3922 -- Attribute 'Finalization_Size is not defined for class-wide
3923 -- types because it is not possible to know statically whether
3924 -- a definite type will have controlled components or not.
3927 Error_Attr_P
3931 -- The prefix denotes an illegal construct
3933 else
3934 Error_Attr_P
3940 -----------
3941 -- First --
3942 -----------
3945 Check_Array_Or_Scalar_Type;
3946 Bad_Attribute_For_Predicate;
3948 ---------------
3949 -- First_Bit --
3950 ---------------
3953 Check_Component;
3956 -----------------
3957 -- First_Valid --
3958 -----------------
3961 Check_First_Last_Valid;
3964 -----------------
3965 -- Fixed_Value --
3966 -----------------
3969 Check_E1;
3970 Check_Fixed_Point_Type;
3974 -----------
3975 -- Floor --
3976 -----------
3979 Check_Floating_Point_Type_1;
3983 ----------
3984 -- Fore --
3985 ----------
3988 Check_Fixed_Point_Type_0;
3991 --------------
3992 -- Fraction --
3993 --------------
3996 Check_Floating_Point_Type_1;
4000 --------------
4001 -- From_Any --
4002 --------------
4005 Check_E1;
4006 Check_PolyORB_Attribute;
4009 -----------------------
4010 -- Has_Access_Values --
4011 -----------------------
4014 Check_Type;
4015 Check_E0;
4018 ----------------------
4019 -- Has_Same_Storage --
4020 ----------------------
4023 Check_E1;
4025 -- The arguments must be objects of any type
4033 -----------------------
4034 -- Has_Tagged_Values --
4035 -----------------------
4038 Check_Type;
4039 Check_E0;
4042 -----------------------
4043 -- Has_Discriminants --
4044 -----------------------
4047 Legal_Formal_Attribute;
4049 --------------
4050 -- Identity --
4051 --------------
4054 Check_E0;
4060 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to task
4061 -- interface class-wide types.
4070 then
4074 else
4076 Error_Attr_P
4079 else
4080 Error_Attr_P
4085 -----------
4086 -- Image --
4087 -----------
4093 Error_Msg_N
4100 ---------
4101 -- Img --
4102 ---------
4107 -----------
4108 -- Input --
4109 -----------
4112 Check_E1;
4116 -------------------
4117 -- Integer_Value --
4118 -------------------
4121 Check_E1;
4122 Check_Integer_Type;
4125 -- Signal an error if argument type is not a specific fixed-point
4126 -- subtype. An error has been signalled already if the argument
4127 -- was not of a fixed-point type.
4135 -------------------
4136 -- Invalid_Value --
4137 -------------------
4140 Check_E0;
4141 Check_Scalar_Type;
4145 -----------
4146 -- Large --
4147 -----------
4150 Check_E0;
4151 Check_Real_Type;
4154 ----------
4155 -- Last --
4156 ----------
4159 Check_Array_Or_Scalar_Type;
4160 Bad_Attribute_For_Predicate;
4162 --------------
4163 -- Last_Bit --
4164 --------------
4167 Check_Component;
4170 ----------------
4171 -- Last_Valid --
4172 ----------------
4175 Check_First_Last_Valid;
4178 ------------------
4179 -- Leading_Part --
4180 ------------------
4183 Check_Floating_Point_Type_2;
4188 ------------
4189 -- Length --
4190 ------------
4193 Check_Array_Type;
4196 -------------------
4197 -- Library_Level --
4198 -------------------
4201 Check_E0;
4214 ---------------
4215 -- Lock_Free --
4216 ---------------
4219 Check_E0;
4223 Error_Attr_P
4227 ----------------
4228 -- Loop_Entry --
4229 ----------------
4233 -- Inspect the prefix for any uses of entities declared within the
4234 -- related loop. Loop_Id denotes the loop identifier.
4236 --------------------------------
4237 -- Check_References_In_Prefix --
4238 --------------------------------
4244 -- Determine whether a reference mentions an entity declared
4245 -- within the related loop.
4248 -- Determine whether Nod appears in the subtree of Loop_Decl
4250 ---------------------
4251 -- Check_Reference --
4252 ---------------------
4255 begin
4259 then
4260 Error_Attr
4262 Nod);
4264 else
4271 ---------------------
4272 -- Declared_Within --
4273 ---------------------
4278 begin
4284 -- Prevent the search from going too far
4296 -- Start of processing for Check_Prefix_For_Local_References
4298 begin
4302 -- Local variables
4312 -- Start of processing for Loop_Entry
4314 begin
4317 -- Set the type of the attribute now to ensure the successful
4318 -- continuation of analysis even if the attribute is misplaced.
4322 -- Attribute 'Loop_Entry may appear in several flavors:
4324 -- * Prefix'Loop_Entry - in this form, the attribute applies to the
4325 -- nearest enclosing loop.
4327 -- * Prefix'Loop_Entry (Expr) - depending on what Expr denotes, the
4328 -- attribute may be related to a loop denoted by label Expr or
4329 -- the prefix may denote an array object and Expr may act as an
4330 -- indexed component.
4332 -- * Prefix'Loop_Entry (Expr1, ..., ExprN) - the attribute applies
4333 -- to the nearest enclosing loop, all expressions are part of
4334 -- an indexed component.
4336 -- * Prefix'Loop_Entry (Expr) (...) (...) - depending on what Expr
4337 -- denotes, the attribute may be related to a loop denoted by
4338 -- label Expr or the prefix may denote a multidimensional array
4339 -- array object and Expr along with the rest of the expressions
4340 -- may act as indexed components.
4342 -- Regardless of variations, the attribute reference does not have an
4343 -- expression list. Instead, all available expressions are stored as
4344 -- indexed components.
4346 -- When the attribute is part of an indexed component, find the first
4347 -- expression as it will determine the semantics of 'Loop_Entry.
4349 -- If the attribute is itself an index in an indexed component, i.e.
4350 -- a member of a list, the context itself is not relevant (the code
4351 -- below would lead to an infinite loop) and the attribute applies
4352 -- to the enclosing loop.
4356 then
4360 -- The attribute reference appears in the following form:
4362 -- Prefix'Loop_Entry (Exp1, Expr2, ..., ExprN) [(...)]
4364 -- In this case, the loop name is omitted and no rewriting is
4365 -- required.
4370 -- The form of the attribute is:
4372 -- Prefix'Loop_Entry (Expr) [(...)]
4374 -- If Expr denotes a loop entry, the whole attribute and indexed
4375 -- component will have to be rewritten to reflect this relation.
4377 else
4380 -- Do not expand the expression as it may have side effects.
4381 -- Simply preanalyze to determine whether it is a loop name or
4382 -- something else.
4389 then
4392 -- Transform the attribute and enclosing indexed component
4403 -- The prefix must denote an object
4409 -- The prefix cannot be of a limited type because the expansion of
4410 -- Loop_Entry must create a constant initialized by the evaluated
4411 -- prefix.
4417 -- Climb the parent chain to verify the location of the attribute and
4418 -- find the enclosing loop.
4423 -- Locate the corresponding enclosing pragma. Note that in the
4424 -- case of Assert[And_Cut] and Assume, we have already checked
4425 -- that the pragma appears in an appropriate loop location.
4429 Name_Loop_Invariant,
4430 Name_Loop_Variant,
4431 Name_Assert,
4432 Name_Assert_And_Cut,
4433 Name_Assume)
4434 then
4437 -- Locate the enclosing loop (if any). Note that Ada 2012 array
4438 -- iteration may be expanded into several nested loops, we are
4439 -- interested in the outermost one which has the loop identifier,
4440 -- and comes from source.
4446 then
4449 -- The original attribute reference may lack a loop name. Use
4450 -- the name of the enclosing loop because it is the related
4451 -- loop.
4459 -- Prevent the search from going too far
4468 -- Loop_Entry must appear within a Loop_Assertion pragma (Assert,
4469 -- Assert_And_Cut, Assume count as loop assertion pragmas for this
4470 -- purpose if they appear in an appropriate location in a loop,
4471 -- which was already checked by the top level pragma circuit).
4473 -- Loop_Entry also denotes a value and as such can appear within an
4474 -- expression that is an argument for another loop aspect. In that
4475 -- case it will have been expanded into the corresponding assignment.
4477 if Expander_Active
4480 then
4487 -- A Loop_Entry that applies to a given loop statement must not
4488 -- appear within a body of accept statement, if this construct is
4489 -- itself enclosed by the given loop statement.
4498 else
4499 Error_Attr
4505 -- The prefix cannot mention entities declared within the related
4506 -- loop because they will not be visible once the prefix is moved
4507 -- outside the loop.
4511 -- The prefix must denote a static entity if the pragma does not
4512 -- apply to the innermost enclosing loop statement, or if it appears
4513 -- within a potentially unevaluated epxression.
4518 then
4523 then
4524 Error_Attr_P
4529 Uneval_Old_Msg;
4532 -- Replace the Loop_Entry attribute reference by its prefix if the
4533 -- related pragma is ignored. This transformation is OK with respect
4534 -- to typing because Loop_Entry's type is that of its prefix. This
4535 -- early transformation also avoids the generation of a useless loop
4536 -- entry constant.
4542 else
4547 -------------
4548 -- Machine --
4549 -------------
4552 Check_Floating_Point_Type_1;
4556 ------------------
4557 -- Machine_Emax --
4558 ------------------
4561 Check_Floating_Point_Type_0;
4564 ------------------
4565 -- Machine_Emin --
4566 ------------------
4569 Check_Floating_Point_Type_0;
4572 ----------------------
4573 -- Machine_Mantissa --
4574 ----------------------
4577 Check_Floating_Point_Type_0;
4580 -----------------------
4581 -- Machine_Overflows --
4582 -----------------------
4585 Check_Real_Type;
4586 Check_E0;
4589 -------------------
4590 -- Machine_Radix --
4591 -------------------
4594 Check_Real_Type;
4595 Check_E0;
4598 ----------------------
4599 -- Machine_Rounding --
4600 ----------------------
4603 Check_Floating_Point_Type_1;
4607 --------------------
4608 -- Machine_Rounds --
4609 --------------------
4612 Check_Real_Type;
4613 Check_E0;
4616 ------------------
4617 -- Machine_Size --
4618 ------------------
4621 Check_E0;
4622 Check_Type;
4623 Check_Not_Incomplete_Type;
4626 --------------
4627 -- Mantissa --
4628 --------------
4631 Check_E0;
4632 Check_Real_Type;
4635 ---------
4636 -- Max --
4637 ---------
4640 Min_Max;
4642 ----------------------------------
4643 -- Max_Alignment_For_Allocation --
4644 ----------------------------------
4647 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4649 ----------------------------------
4650 -- Max_Size_In_Storage_Elements --
4651 ----------------------------------
4654 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4656 -----------------------
4657 -- Maximum_Alignment --
4658 -----------------------
4663 --------------------
4664 -- Mechanism_Code --
4665 --------------------
4670 then
4674 Check_Either_E0_Or_E1;
4681 Flag_Non_Static_Expr
4683 Error_Attr;
4687 then
4694 ---------
4695 -- Min --
4696 ---------
4699 Min_Max;
4701 ---------
4702 -- Mod --
4703 ---------
4707 -- Note: this attribute is only allowed in Ada 2005 mode, but
4708 -- we do not need to test that here, since Mod is only recognized
4709 -- as an attribute name in Ada 2005 mode during the parse.
4711 Check_E1;
4712 Check_Modular_Integer_Type;
4716 -----------
4717 -- Model --
4718 -----------
4721 Check_Floating_Point_Type_1;
4725 ----------------
4726 -- Model_Emin --
4727 ----------------
4730 Check_Floating_Point_Type_0;
4733 -------------------
4734 -- Model_Epsilon --
4735 -------------------
4738 Check_Floating_Point_Type_0;
4741 --------------------
4742 -- Model_Mantissa --
4743 --------------------
4746 Check_Floating_Point_Type_0;
4749 -----------------
4750 -- Model_Small --
4751 -----------------
4754 Check_Floating_Point_Type_0;
4757 -------------
4758 -- Modulus --
4759 -------------
4762 Check_E0;
4763 Check_Modular_Integer_Type;
4766 --------------------
4767 -- Null_Parameter --
4768 --------------------
4775 -- Used if bad Null parameter attribute node is found. Issues
4776 -- given error message, and also sets the type to Any_Type to
4777 -- avoid blowups later on from dealing with a junk node.
4780 -- Called to check that Proc_Ent is imported subprogram
4782 ------------------------
4783 -- Bad_Null_Parameter --
4784 ------------------------
4787 begin
4792 ----------------------
4793 -- Must_Be_Imported --
4794 ----------------------
4799 begin
4800 -- Ignore check if procedure not frozen yet (we will get
4801 -- another chance when the default parameter is reanalyzed)
4807 Bad_Null_Parameter
4810 else
4815 -- Start of processing for Null_Parameter
4817 begin
4818 Check_Type;
4819 Check_E0;
4822 -- Case of attribute used as default expression
4827 -- Case of attribute used as actual for subprogram (positional)
4831 then
4834 -- Case of attribute used as actual for subprogram (named)
4839 then
4842 -- Not an allowed case
4844 else
4845 Bad_Null_Parameter
4850 -----------------
4851 -- Object_Size --
4852 -----------------
4855 Check_E0;
4856 Check_Type;
4857 Check_Not_Incomplete_Type;
4860 ---------
4861 -- Old --
4862 ---------
4866 -- Inspect the contents of the prefix and detect illegal uses of a
4867 -- nested 'Old, attribute 'Result or a use of an entity declared in
4868 -- the related postcondition expression. Subp_Id is the subprogram to
4869 -- which the related postcondition applies.
4871 --------------------------------
4872 -- Check_References_In_Prefix --
4873 --------------------------------
4877 -- Detect attribute 'Old, attribute 'Result of a use of an entity
4878 -- and perform the appropriate semantic check.
4880 ---------------------
4881 -- Check_Reference --
4882 ---------------------
4885 begin
4886 -- Attributes 'Old and 'Result cannot appear in the prefix of
4887 -- another attribute 'Old.
4891 Name_Result)
4892 then
4895 Error_Msg_N
4897 Nod);
4900 -- Entities mentioned within the prefix of attribute 'Old must
4901 -- be global to the related postcondition. If this is not the
4902 -- case, then the scope of the local entity is nested within
4903 -- that of the subprogram.
4908 then
4909 Error_Attr
4911 Nod);
4914 -- Otherwise keep inspecting the prefix
4916 else
4923 -- Start of processing for Check_References_In_Prefix
4925 begin
4929 -- Local variables
4936 -- Start of processing for Old
4938 begin
4939 -- The attribute reference is a primary. If any expressions follow,
4940 -- then the attribute reference is an indexable object. Transform the
4941 -- attribute into an indexed component and analyze it.
4946 Prefix =>
4957 -- The aspect or pragma where attribute 'Old resides should be
4958 -- associated with a subprogram declaration or a body. If this is not
4959 -- the case, then the aspect or pragma is illegal. Return as analysis
4960 -- cannot be carried out.
4962 -- The exception to this rule is when generating C since in this case
4963 -- postconditions are inlined.
4966 and then Modify_Tree_For_C
4967 and then In_Inlined_Body
4968 then
4975 -- The prefix must be preanalyzed as the full analysis will take
4976 -- place during expansion.
4980 -- Ensure that the prefix does not contain attributes 'Old or 'Result
4984 -- Set the type of the attribute now to prevent cascaded errors
4989 -- Legality checks
4995 -- The prefix is a simple name
5000 -- Emit a warning when the prefix is a constant. Note that the use
5001 -- of Error_Attr would reset the type of N to Any_Type even though
5002 -- this is a warning. Use Error_Msg_XXX instead.
5006 Error_Msg_N
5010 -- Otherwise the prefix is not a simple name
5012 else
5013 -- Ensure that the prefix of attribute 'Old is an entity when it
5014 -- is potentially unevaluated (6.1.1 (27/3)).
5018 then
5019 Uneval_Old_Msg;
5021 -- Detect a possible infinite recursion when the prefix denotes
5022 -- the related function.
5024 -- function Func (...) return ...
5025 -- with Post => Func'Old ...;
5027 -- The function may be specified in qualified form X.Y where X is
5028 -- a protected object and Y is a protected function. In that case
5029 -- ensure that the qualified form has an entity.
5033 then
5038 then
5045 -- The prefix of attribute 'Old may refer to a component of a
5046 -- formal parameter. In this case its expansion may generate
5047 -- actual subtypes that are referenced in an inner context and
5048 -- that must be elaborated within the subprogram itself. If the
5049 -- prefix includes a function call, it may involve finalization
5050 -- actions that should be inserted when the attribute has been
5051 -- rewritten as a declaration. Create a declaration for the prefix
5052 -- and insert it at the start of the enclosing subprogram. This is
5053 -- an expansion activity that has to be performed now to prevent
5054 -- out-of-order issues.
5056 -- This expansion is both harmful and not needed in SPARK mode,
5057 -- since the formal verification back end relies on the types of
5058 -- nodes (hence is not robust w.r.t. a change to base type here),
5059 -- and does not suffer from the out-of-order issue described
5060 -- above. Thus, this expansion is skipped in SPARK mode.
5062 -- The expansion is not relevant for discrete types, which will
5063 -- not generate extra declarations, and where use of the base type
5064 -- may lead to spurious errors if context is a case.
5080 ----------------------
5081 -- Overlaps_Storage --
5082 ----------------------
5085 Check_E1;
5087 -- Both arguments must be objects of any type
5095 ------------
5096 -- Output --
5097 ------------
5100 Check_E2;
5105 ------------------
5106 -- Partition_ID --
5107 ------------------
5110 Check_E0;
5114 Error_Attr_P
5117 -- The defining entity of prefix should not be declared inside a
5118 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
5122 then
5129 -------------------------
5130 -- Passed_By_Reference --
5131 -------------------------
5134 Check_E0;
5135 Check_Type;
5138 ------------------
5139 -- Pool_Address --
5140 ------------------
5143 Check_E0;
5146 ---------
5147 -- Pos --
5148 ---------
5151 Check_Discrete_Type;
5152 Check_E1;
5157 Check_SPARK_05_Restriction
5164 --------------
5165 -- Position --
5166 --------------
5169 Check_Component;
5172 ----------
5173 -- Pred --
5174 ----------
5177 Check_Scalar_Type;
5178 Check_E1;
5183 Check_SPARK_05_Restriction
5190 -- Since Pred works on the base type, we normally do no check for the
5191 -- floating-point case, since the base type is unconstrained. But we
5192 -- make an exception in Check_Float_Overflow mode.
5199 -- If not modular type, test for overflow check required
5201 else
5204 then
5209 --------------
5210 -- Priority --
5211 --------------
5213 -- Ada 2005 (AI-327): Dynamic ceiling priorities
5220 Check_E0;
5224 -- The prefix must be a protected object (AARM D.5.2 (2/2))
5231 then
5233 else
5239 -- Must be called from within a protected procedure or entry of the
5240 -- protected object.
5242 declare
5245 begin
5249 loop
5259 Validate_Non_Static_Attribute_Function_Call;
5261 -----------
5262 -- Range --
5263 -----------
5266 Check_Array_Or_Scalar_Type;
5267 Bad_Attribute_For_Predicate;
5272 then
5273 Error_Attr
5277 ------------
5278 -- Result --
5279 ------------
5282 function Denote_Same_Function
5285 -- Determine whether the entity of the prefix Pref_Id denotes the
5286 -- same entity as that of the related subprogram Spec_Id.
5288 --------------------------
5289 -- Denote_Same_Function --
5290 --------------------------
5292 function Denote_Same_Function
5295 is
5299 begin
5300 -- The prefix denotes the related subprogram
5305 -- Account for a special case when attribute 'Result appears in
5306 -- the postcondition of a generic function.
5308 -- generic
5309 -- function Gen_Func return ...
5310 -- with Post => Gen_Func'Result ...;
5312 -- When the generic function is instantiated, the Chars field of
5313 -- the instantiated prefix still denotes the name of the generic
5314 -- function. Note that any preemptive transformation is impossible
5315 -- without a proper analysis. The structure of the wrapper package
5316 -- is as follows:
5318 -- package Anon_Gen_Pack is
5319 -- <subtypes and renamings>
5320 -- function Subp_Decl return ...; -- (!)
5321 -- pragma Postcondition (Gen_Func'Result ...); -- (!)
5322 -- function Gen_Func ... renames Subp_Decl;
5323 -- end Anon_Gen_Pack;
5328 then
5334 then
5338 -- Account for a special case where a primitive of a tagged type
5339 -- inherits a class-wide postcondition from a parent type. In this
5340 -- case the prefix of attribute 'Result denotes the overriding
5341 -- primitive.
5347 -- Otherwise the prefix does not denote the related subprogram
5352 -- Local variables
5355 Modify_Tree_For_C
5362 -- Start of processing for Result
5364 begin
5365 -- The attribute reference is a primary. If any expressions follow,
5366 -- then the attribute reference is an indexable object. Transform the
5367 -- attribute into an indexed component and analyze it.
5372 Prefix =>
5383 -- The aspect or pragma where attribute 'Result resides should be
5384 -- associated with a subprogram declaration or a body. If this is not
5385 -- the case, then the aspect or pragma is illegal. Return as analysis
5386 -- cannot be carried out.
5388 -- The exception to this rule is when generating C since in this case
5389 -- postconditions are inlined.
5398 -- Attribute 'Result is part of a _Postconditions procedure. There is
5399 -- no need to perform the semantic checks below as they were already
5400 -- verified when the attribute was analyzed in its original context.
5401 -- Instead, rewrite the attribute as a reference to formal parameter
5402 -- _Result of the _Postconditions procedure.
5405 or else
5406 (In_Inlined_C_Postcondition
5408 then
5411 -- The type of formal parameter _Result is that of the function
5412 -- encapsulating the _Postconditions procedure. Resolution must
5413 -- be carried out against the function return type.
5417 -- Otherwise attribute 'Result appears in its original context and
5418 -- all semantic checks should be carried out.
5420 else
5421 -- Verify the legality of the prefix. It must denotes the entity
5422 -- of the related [generic] function.
5429 then
5432 -- Correct the prefix of the attribute when the context
5433 -- is a generic function.
5442 -- Otherwise the prefix denotes some unrelated function
5444 else
5446 Error_Attr
5450 -- Otherwise the prefix denotes some other form of subprogram
5451 -- entity.
5453 else
5454 Error_Attr
5459 -- Otherwise the prefix is illegal
5461 else
5468 ------------------
5469 -- Range_Length --
5470 ------------------
5473 Check_E0;
5474 Check_Discrete_Type;
5477 ----------
5478 -- Read --
5479 ----------
5482 Check_E2;
5488 ---------
5489 -- Ref --
5490 ---------
5493 Check_E1;
5498 then
5505 ---------------
5506 -- Remainder --
5507 ---------------
5510 Check_Floating_Point_Type_2;
5515 ---------------------
5516 -- Restriction_Set --
5517 ---------------------
5524 begin
5525 Check_E1;
5527 Check_System_Prefix;
5529 -- No_Dependence case
5537 Error_Attr;
5540 -- See if there is an entry already in the table. That's the
5541 -- case in which we can return True.
5546 then
5552 -- If not in the No_Dependence table, result is False
5556 -- In this case, we must ensure that the binder will reject any
5557 -- other unit in the partition that sets No_Dependence for this
5558 -- unit. We do that by making an entry in the special table kept
5559 -- for this purpose (if the entry is not there already).
5564 Restriction_Set_Dependences.Last
5565 loop
5573 -- Normal restriction case
5575 else
5580 else
5591 Error_Attr
5597 else
5605 -----------
5606 -- Round --
5607 -----------
5610 Check_E1;
5611 Check_Decimal_Fixed_Point_Type;
5614 -- Because the context is universal_real (3.5.10(12)) it is a
5615 -- legal context for a universal fixed expression. This is the
5616 -- only attribute whose functional description involves U_R.
5619 declare
5624 begin
5632 --------------
5633 -- Rounding --
5634 --------------
5637 Check_Floating_Point_Type_1;
5641 ---------------
5642 -- Safe_Emax --
5643 ---------------
5646 Check_Floating_Point_Type_0;
5649 ----------------
5650 -- Safe_First --
5651 ----------------
5654 Check_Floating_Point_Type_0;
5657 ----------------
5658 -- Safe_Large --
5659 ----------------
5662 Check_E0;
5663 Check_Real_Type;
5666 ---------------
5667 -- Safe_Last --
5668 ---------------
5671 Check_Floating_Point_Type_0;
5674 ----------------
5675 -- Safe_Small --
5676 ----------------
5679 Check_E0;
5680 Check_Real_Type;
5683 --------------------------
5684 -- Scalar_Storage_Order --
5685 --------------------------
5690 begin
5691 Check_E0;
5692 Check_Type;
5696 -- In GNAT mode, the attribute applies to generic types as well
5697 -- as composite types, and for non-composite types always returns
5698 -- the default bit order for the target.
5701 and then not In_Instance
5702 then
5703 Error_Attr_P
5709 else
5717 else
5728 -- Reset incorrect indication of staticness
5733 -----------
5734 -- Scale --
5735 -----------
5738 Check_E0;
5739 Check_Decimal_Fixed_Point_Type;
5742 -------------
5743 -- Scaling --
5744 -------------
5747 Check_Floating_Point_Type_2;
5751 ------------------
5752 -- Signed_Zeros --
5753 ------------------
5756 Check_Floating_Point_Type_0;
5759 ----------
5760 -- Size --
5761 ----------
5763 when Attribute_Size
5764 | Attribute_VADS_Size
5765 =>
5766 Check_E0;
5768 -- If prefix is parameterless function call, rewrite and resolve
5769 -- as such.
5773 then
5776 -- Similar processing for a protected function call
5780 then
5790 then
5795 then
5798 -- Some other compilers allow dubious use of X'???'Size
5800 elsif Relaxed_RM_Semantics
5802 then
5805 else
5809 Check_Not_Incomplete_Type;
5810 Check_Not_CPP_Type;
5813 -- If we are processing pragmas Compile_Time_Warning and Compile_
5814 -- Time_Errors after the back end has been called and this occurrence
5815 -- of 'Size is known at compile time then it is safe to perform this
5816 -- evaluation. Needed to perform the static evaluation of the full
5817 -- boolean expression of these pragmas.
5819 if In_Compile_Time_Warning_Or_Error
5824 then
5829 -----------
5830 -- Small --
5831 -----------
5834 Check_E0;
5835 Check_Real_Type;
5838 ------------------
5839 -- Storage_Pool --
5840 ------------------
5842 when Attribute_Storage_Pool
5843 | Attribute_Simple_Storage_Pool
5844 =>
5845 Check_E0;
5849 Error_Attr_P
5853 -- Set appropriate entity
5857 else
5863 Name_Simple_Storage_Pool_Type))
5864 then
5867 Error_Msg_N
5872 Rewrite
5879 -- In the Simple_Storage_Pool case, verify that the pool entity is
5880 -- actually of a simple storage pool type, and set the attribute's
5881 -- type to the pool object's type.
5883 else
5885 Name_Simple_Storage_Pool_Type))
5886 then
5887 Error_Attr_P
5895 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5896 -- Storage_Pool since this attribute is not defined for such
5897 -- types (RM E.2.3(22)).
5901 else
5905 ------------------
5906 -- Storage_Size --
5907 ------------------
5910 Check_E0;
5915 -- Use with tasks is an obsolescent feature
5921 Error_Attr_P
5927 then
5928 Check_Type;
5931 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5932 -- Storage_Size since this attribute is not defined for
5933 -- such types (RM E.2.3(22)).
5937 -- The prefix is allowed to be an implicit dereference of an
5938 -- access value designating a task.
5940 else
5941 Check_Task_Prefix;
5945 else
5949 ------------------
5950 -- Storage_Unit --
5951 ------------------
5956 -----------------
5957 -- Stream_Size --
5958 -----------------
5961 Check_E0;
5962 Check_Type;
5966 then
5968 else
5972 ---------------
5973 -- Stub_Type --
5974 ---------------
5977 Check_Type;
5978 Check_E0;
5982 -- For a real RACW [sub]type, use corresponding stub type
5986 New_Occurrence_Of
5989 -- For a generic type (that has been marked as an RACW using the
5990 -- Remote_Access_Type aspect or pragma), use a generic RACW stub
5991 -- type. Note that if the actual is not a remote access type, the
5992 -- instantiation will fail.
5994 else
5995 -- Note: we go to the underlying type here because the view
5996 -- returned by RTE (RE_RACW_Stub_Type) might be incomplete.
5999 New_Occurrence_Of
6003 else
6004 Error_Attr_P
6008 ----------
6009 -- Succ --
6010 ----------
6013 Check_Scalar_Type;
6014 Check_E1;
6019 Check_SPARK_05_Restriction
6026 -- Since Pred works on the base type, we normally do no check for the
6027 -- floating-point case, since the base type is unconstrained. But we
6028 -- make an exception in Check_Float_Overflow mode.
6035 -- If not modular type, test for overflow check required
6037 else
6040 then
6045 --------------------------------
6046 -- System_Allocator_Alignment --
6047 --------------------------------
6052 ---------
6053 -- Tag --
6054 ---------
6057 Check_E0;
6058 Check_Dereference;
6063 -- Next test does not apply to generated code why not, and what does
6064 -- the illegal reference mean???
6069 then
6070 Error_Attr_P
6075 -- The prefix cannot be an incomplete type. However, references to
6076 -- 'Tag can be generated when expanding interface conversions, and
6077 -- this is legal.
6080 Check_Not_Incomplete_Type;
6083 -- Set appropriate type
6087 -----------------
6088 -- Target_Name --
6089 -----------------
6095 begin
6096 Check_Standard_Prefix;
6111 ----------------
6112 -- Terminated --
6113 ----------------
6116 Check_E0;
6118 Check_Task_Prefix;
6120 ----------------
6121 -- To_Address --
6122 ----------------
6127 begin
6128 Check_E1;
6130 Check_System_Prefix;
6140 -- OK static expression case, check range and set appropriate type
6146 or else
6148 then
6152 -- In most cases the expression is a numeric literal or some other
6153 -- address expression, but if it is a declared constant it may be
6154 -- of a compatible type that must be left on the node.
6159 -- Set type to universal integer if negative
6164 -- Otherwise set type to Unsigned_64 to accommodate max values
6166 else
6174 ------------
6175 -- To_Any --
6176 ------------
6179 Check_E1;
6180 Check_PolyORB_Attribute;
6183 ----------------
6184 -- Truncation --
6185 ----------------
6188 Check_Floating_Point_Type_1;
6192 ----------------
6193 -- Type_Class --
6194 ----------------
6197 Check_E0;
6198 Check_Type;
6199 Check_Not_Incomplete_Type;
6202 --------------
6203 -- TypeCode --
6204 --------------
6207 Check_E0;
6208 Check_PolyORB_Attribute;
6211 --------------
6212 -- Type_Key --
6213 --------------
6220 -- The computed signature for the type
6223 -- To simplify the handling of mutually recursive types, follow a
6224 -- single dereference link in a composite type.
6227 -- Create a CRC integer from the declaration of the type. For a
6228 -- composite type, fold in the representation of its components in
6229 -- recursive fashion. We use directly the source representation of
6230 -- the types involved.
6232 ----------------------
6233 -- Compute_Type_Key --
6234 ----------------------
6244 -- Update CRC with the characters of one type declaration, or a
6245 -- representation pragma that applies to the type.
6247 -----------------------------
6248 -- Process_One_Declaration --
6249 -----------------------------
6252 begin
6253 -- Scan type declaration, skipping blanks
6262 -- Start of processing for Compute_Type_Key
6264 begin
6269 -- If the type is declared in Standard, there is no source, so
6270 -- just use its name.
6273 declare
6275 begin
6289 Process_One_Declaration;
6291 -- Recurse on relevant component types
6306 declare
6308 begin
6319 -- Fold in representation aspects for the type, which appear in
6320 -- the same source buffer. If the representation aspects are in
6321 -- a different source file, then skip them; they apply to some
6322 -- other type, perhaps one we're derived from.
6332 Process_One_Declaration;
6341 -- Start of processing for Type_Key
6343 begin
6344 Check_E0;
6345 Check_Type;
6347 Start_String;
6350 -- Copy all characters in Full_Name but the trailing NUL
6356 -- Compute CRC and convert it to string one character at a time, so
6357 -- as not to use Image within the compiler.
6375 -----------------------
6376 -- Unbiased_Rounding --
6377 -----------------------
6380 Check_Floating_Point_Type_1;
6384 ----------------------
6385 -- Unchecked_Access --
6386 ----------------------
6393 Analyze_Access_Attribute;
6394 Check_Not_Incomplete_Type;
6396 -------------------------
6397 -- Unconstrained_Array --
6398 -------------------------
6401 Check_E0;
6402 Check_Type;
6403 Check_Not_Incomplete_Type;
6407 ------------------------------
6408 -- Universal_Literal_String --
6409 ------------------------------
6411 -- This is a GNAT specific attribute whose prefix must be a named
6412 -- number where the expression is either a single numeric literal,
6413 -- or a numeric literal immediately preceded by a minus sign. The
6414 -- result is equivalent to a string literal containing the text of
6415 -- the literal as it appeared in the source program with a possible
6416 -- leading minus sign.
6419 Check_E0;
6423 then
6426 else
6427 declare
6433 begin
6439 else
6444 Error_Attr
6448 -- Build string literal corresponding to source literal text
6450 Start_String;
6464 -- Now we rewrite the attribute with the string literal
6473 -------------------------
6474 -- Unrestricted_Access --
6475 -------------------------
6477 -- This is a GNAT specific attribute which is like Access except that
6478 -- all scope checks and checks for aliased views are omitted. It is
6479 -- documented as being equivalent to the use of the Address attribute
6480 -- followed by an unchecked conversion to the target access type.
6484 -- If from source, deal with relevant restrictions
6492 then
6501 -- It might seem reasonable to call Address_Checks here to apply the
6502 -- same set of semantic checks that we enforce for 'Address (after
6503 -- all we document Unrestricted_Access as being equivalent to the
6504 -- use of Address followed by an Unchecked_Conversion). However, if
6505 -- we do enable these checks, we get multiple failures in both the
6506 -- compiler run-time and in our regression test suite, so we leave
6507 -- out these checks for now. To be investigated further some time???
6509 -- Address_Checks;
6511 -- Now complete analysis using common access processing
6513 Analyze_Access_Attribute;
6515 ------------
6516 -- Update --
6517 ------------
6521 -- The common type of a multiple component update for a record
6524 -- A list used in the resolution of a record update. It contains the
6525 -- entities of all record components processed so far.
6528 -- Analyze and resolve array_component_association Assoc against the
6529 -- index of array type P_Type.
6532 -- Analyze and resolve record_component_association Comp against
6533 -- record type P_Type.
6535 ------------------------------------
6536 -- Analyze_Array_Component_Update --
6537 ------------------------------------
6546 begin
6547 -- The current association contains a sequence of indexes denoting
6548 -- an element of a multidimensional array:
6550 -- (Index_1, ..., Index_N)
6552 -- Examine each individual index and resolve it against the proper
6553 -- index type of the array.
6559 -- The use of others is illegal (SPARK RM 4.4.1(12))
6562 Error_Attr
6565 -- Otherwise analyze and resolve all indexes
6567 else
6576 -- Detect a case where the association either lacks an
6577 -- index or contains an extra index.
6580 Error_Msg_N
6588 -- The current association denotes either a single component or a
6589 -- range of components of a one dimensional array:
6591 -- 1, 2 .. 5
6593 -- Resolve the index or its high and low bounds (if range) against
6594 -- the proper index type of the array.
6596 else
6606 -- The use of others is illegal (SPARK RM 4.4.1(12))
6609 Error_Attr
6612 -- The index denotes a range of elements
6621 -- Add a range check to ensure that the bounds of the
6622 -- range are within the index type when this cannot be
6623 -- determined statically.
6633 -- Otherwise the index denotes a single element
6635 else
6638 -- Add a range check to ensure that the index is within
6639 -- the index type when it is not possible to determine
6640 -- this statically.
6652 -------------------------------------
6653 -- Analyze_Record_Component_Update --
6654 -------------------------------------
6661 begin
6662 -- Find the discriminant or component whose name corresponds to
6663 -- Comp. A simple character comparison is sufficient because all
6664 -- visible names within a record type are unique.
6670 -- Decorate the component reference by setting its entity
6671 -- and type for resolution purposes.
6681 -- Diagnose an illegal reference
6685 Error_Attr
6692 -- Mark this component as processed
6694 else
6699 -- The update aggregate mentions an entity that does not belong to
6700 -- the record type.
6702 else
6706 -- Verify the consistency of types when the current component is
6707 -- part of a miltiple component update.
6709 -- Comp_1, ..., Comp_N => <value>
6714 -- Save the type of the first component reference as the
6715 -- remaning references (if any) must resolve to this type.
6721 Error_Msg_N
6727 -- Local variables
6732 -- Start of processing for Update
6734 begin
6735 Check_E1;
6742 then
6752 -- Inspect the update aggregate, looking at all the associations and
6753 -- choices. Perform the following checks:
6755 -- 1) Legality of "others" in all cases
6756 -- 2) Legality of <>
6757 -- 3) Component legality for arrays
6758 -- 4) Component legality for records
6760 -- The remaining checks are performed on the expanded attribute
6765 -- The use of <> is illegal (SPARK RM 4.4.1(1))
6768 Error_Attr
6771 -- Otherwise process the association
6773 else
6781 -- Reset the common type used in a multiple component update
6782 -- as we are processing the contents of a new association.
6791 -- The use of others is illegal (SPARK RM 4.4.1(5))
6794 Error_Attr
6797 -- The name of a record component cannot appear in any
6798 -- other form.
6800 else
6801 Error_Msg_N
6813 -- The type of attribute 'Update is that of the prefix
6820 ---------
6821 -- Val --
6822 ---------
6825 Check_E1;
6826 Check_Discrete_Type;
6831 Check_SPARK_05_Restriction
6835 -- Note, we need a range check in general, but we wait for the
6836 -- Resolve call to do this, since we want to let Eval_Attribute
6837 -- have a chance to find an static illegality first.
6842 -----------
6843 -- Valid --
6844 -----------
6847 Check_E0;
6849 -- Ignore check for object if we have a 'Valid reference generated
6850 -- by the expanded code, since in some cases valid checks can occur
6851 -- on items that are names, but are not objects (e.g. attributes).
6861 -- If the attribute appears within the subtype's own predicate
6862 -- function, then issue a warning that this will cause infinite
6863 -- recursion.
6865 declare
6868 begin
6870 Error_Msg_N
6878 -------------------
6879 -- Valid_Scalars --
6880 -------------------
6883 Check_E0;
6887 -- Following checks are only for source types
6891 Error_Attr_P
6895 -- Not allowed for unchecked union type
6898 Error_Attr_P
6903 -----------
6904 -- Value --
6905 -----------
6908 Check_SPARK_05_Restriction_On_Attribute;
6909 Check_E1;
6910 Check_Scalar_Type;
6912 -- Case of enumeration type
6914 -- When an enumeration type appears in an attribute reference, all
6915 -- literals of the type are marked as referenced. This must only be
6916 -- done if the attribute reference appears in the current source.
6917 -- Otherwise the information on references may differ between a
6918 -- normal compilation and one that performs inlining.
6922 then
6925 -- Mark all enumeration literals as referenced, since the use of
6926 -- the Value attribute can implicitly reference any of the
6927 -- literals of the enumeration base type.
6929 declare
6931 begin
6939 -- Set Etype before resolving expression because expansion of
6940 -- expression may require enclosing type. Note that the type
6941 -- returned by 'Value is the base type of the prefix type.
6944 Validate_Non_Static_Attribute_Function_Call;
6946 -- Check restriction No_Fixed_IO
6950 then
6954 ----------------
6955 -- Value_Size --
6956 ----------------
6959 Check_E0;
6960 Check_Type;
6961 Check_Not_Incomplete_Type;
6964 -------------
6965 -- Version --
6966 -------------
6969 Check_E0;
6970 Check_Program_Unit;
6973 ------------------
6974 -- Wchar_T_Size --
6975 ------------------
6980 ----------------
6981 -- Wide_Image --
6982 ----------------
6987 ---------------------
6988 -- Wide_Wide_Image --
6989 ---------------------
6994 ----------------
6995 -- Wide_Value --
6996 ----------------
6999 Check_SPARK_05_Restriction_On_Attribute;
7000 Check_E1;
7001 Check_Scalar_Type;
7003 -- Set Etype before resolving expression because expansion
7004 -- of expression may require enclosing type.
7007 Validate_Non_Static_Attribute_Function_Call;
7009 -- Check restriction No_Fixed_IO
7013 then
7017 ---------------------
7018 -- Wide_Wide_Value --
7019 ---------------------
7022 Check_E1;
7023 Check_Scalar_Type;
7025 -- Set Etype before resolving expression because expansion
7026 -- of expression may require enclosing type.
7029 Validate_Non_Static_Attribute_Function_Call;
7031 -- Check restriction No_Fixed_IO
7035 then
7039 ---------------------
7040 -- Wide_Wide_Width --
7041 ---------------------
7044 Check_E0;
7045 Check_Scalar_Type;
7048 ----------------
7049 -- Wide_Width --
7050 ----------------
7053 Check_SPARK_05_Restriction_On_Attribute;
7054 Check_E0;
7055 Check_Scalar_Type;
7058 -----------
7059 -- Width --
7060 -----------
7063 Check_SPARK_05_Restriction_On_Attribute;
7064 Check_E0;
7065 Check_Scalar_Type;
7068 ---------------
7069 -- Word_Size --
7070 ---------------
7075 -----------
7076 -- Write --
7077 -----------
7080 Check_E2;
7087 -- In SPARK certain attributes (see below) depend on Tasking_State.
7088 -- Ensure that the entity is available for gnat2why by loading it.
7089 -- See SPARK RM 9(18) for the relevant rule.
7092 declare
7095 begin
7097 when Attribute_Callable
7098 | Attribute_Caller
7099 | Attribute_Count
7100 | Attribute_Terminated
7101 =>
7110 -- All errors raise Bad_Attribute, so that we get out before any further
7111 -- damage occurs when an error is detected (for example, if we check for
7112 -- one attribute expression, and the check succeeds, we want to be able
7113 -- to proceed securely assuming that an expression is in fact present.
7115 -- Note: we set the attribute analyzed in this case to prevent any
7116 -- attempt at reanalysis which could generate spurious error msgs.
7118 exception
7125 --------------------
7126 -- Eval_Attribute --
7127 --------------------
7136 -- The type imposed by the context
7139 -- First expression, or Empty if none
7142 -- Second expression, or Empty if none
7145 -- Entity denoted by prefix
7148 -- The type of the prefix
7151 -- The base type of the prefix type
7154 -- The root type of the prefix type
7157 -- True if the result is Static. This is set by the general processing
7158 -- to true if the prefix is static, and all expressions are static. It
7159 -- can be reset as processing continues for particular attributes. This
7160 -- flag can still be True if the reference raises a constraint error.
7161 -- Is_Static_Expression (N) is set to follow this value as it is set
7162 -- and we could always reference this, but it is convenient to have a
7163 -- simple short name to use, since it is frequently referenced.
7166 -- Expressions for low and high bounds of type or array index referenced
7167 -- by First, Last, or Length attribute for array, set by Set_Bounds.
7170 -- Constraint error node used if we have an attribute reference has
7171 -- an argument that raises a constraint error. In this case we replace
7172 -- the attribute with a raise constraint_error node. This is important
7173 -- processing, since otherwise gigi might see an attribute which it is
7174 -- unprepared to deal with.
7177 -- If Bound is a reference to a discriminant of a task or protected type
7178 -- occurring within the object's body, rewrite attribute reference into
7179 -- a reference to the corresponding discriminal. Use for the expansion
7180 -- of checks against bounds of entry family index subtypes.
7183 -- In case where the attribute is not foldable, the expressions, if
7184 -- any, of the attribute, are in a non-static context. This procedure
7185 -- performs the required additional checks.
7188 -- Determines if the given type has compile time known bounds. Note
7189 -- that we enter the case statement even in cases where the prefix
7190 -- type does NOT have known bounds, so it is important to guard any
7191 -- attempt to evaluate both bounds with a call to this function.
7194 -- This procedure is called when the attribute N has a non-static
7195 -- but compile time known value given by Val. It includes the
7196 -- necessary checks for out of range values.
7199 -- Computes the Fore value for the current attribute prefix, which is
7200 -- known to be a static fixed-point type. Used by Fore and Width.
7203 -- Returns the Mantissa value for the prefix type
7206 -- Used for First, Last and Length attributes applied to an array or
7207 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
7208 -- and high bound expressions for the index referenced by the attribute
7209 -- designator (i.e. the first index if no expression is present, and the
7210 -- N'th index if the value N is present as an expression). Also used for
7211 -- First and Last of scalar types and for First_Valid and Last_Valid.
7212 -- Static is reset to False if the type or index type is not statically
7213 -- constrained.
7216 -- Verify that the prefix of a potentially static array attribute
7217 -- satisfies the conditions of 4.9 (14).
7219 -----------------------------------
7220 -- Check_Concurrent_Discriminant --
7221 -----------------------------------
7225 -- The concurrent (task or protected) type
7227 begin
7231 then
7236 -- Find discriminant of original concurrent type, and use
7237 -- its current discriminal, which is the renaming within
7238 -- the task/protected body.
7241 New_Occurrence_Of
7247 -----------------------
7248 -- Check_Expressions --
7249 -----------------------
7253 begin
7261 ----------------------------------
7262 -- Compile_Time_Known_Attribute --
7263 ----------------------------------
7268 begin
7271 -- Check that result is in bounds of the type if it is static
7277 Apply_Compile_Time_Constraint_Error
7283 else
7288 -------------------------------
7289 -- Compile_Time_Known_Bounds --
7290 -------------------------------
7293 begin
7294 return
7296 and then
7300 ----------------
7301 -- Fore_Value --
7302 ----------------
7304 -- Note that the Fore calculation is based on the actual values
7305 -- of the bounds, and does not take into account possible rounding.
7316 begin
7317 -- Bounds are given in terms of small units, so first compute
7318 -- proper values as reals.
7323 -- Loop to compute proper value if more than one digit required
7333 --------------
7334 -- Mantissa --
7335 --------------
7337 -- Table of mantissa values accessed by function Computed using
7338 -- the relation:
7340 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
7342 -- where D is T'Digits (RM83 3.5.7)
7387 begin
7388 return
7392 ----------------
7393 -- Set_Bounds --
7394 ----------------
7401 begin
7402 -- For a string literal subtype, we have to construct the bounds.
7403 -- Valid Ada code never applies attributes to string literals, but
7404 -- it is convenient to allow the expander to generate attribute
7405 -- references of this type (e.g. First and Last applied to a string
7406 -- literal).
7408 -- Note that the whole point of the E_String_Literal_Subtype is to
7409 -- avoid this construction of bounds, but the cases in which we
7410 -- have to materialize them are rare enough that we don't worry.
7412 -- The low bound is simply the low bound of the base type. The
7413 -- high bound is computed from the length of the string and this
7414 -- low bound.
7420 Hi_Bound :=
7422 Intval =>
7429 -- For non-array case, just get bounds of scalar type
7434 -- For a fixed-point type, we must freeze to get the attributes
7435 -- of the fixed-point type set now so we can reference them.
7441 then
7445 -- For array case, get type of proper index
7447 else
7450 else
7459 -- If no index type, get out (some other error occurred, and
7460 -- we don't have enough information to complete the job).
7471 -- A discrete range in an index constraint is allowed to be a
7472 -- subtype indication. This is syntactically a pain, but should
7473 -- not propagate to the entity for the corresponding index subtype.
7474 -- After checking that the subtype indication is legal, the range
7475 -- of the subtype indication should be transfered to the entity.
7476 -- The attributes for the bounds should remain the simple retrievals
7477 -- that they are now.
7482 -- If subtype is non-static, result is definitely non-static
7488 -- Subtype is static, does it raise CE?
7495 -------------------------------
7496 -- Statically_Denotes_Entity --
7497 -------------------------------
7502 begin
7505 else
7509 return
7514 -- Start of processing for Eval_Attribute
7516 begin
7517 -- Initialize result as non-static, will be reset if appropriate
7522 -- Acquire first two expressions (at the moment, no attributes take more
7523 -- than two expressions in any case).
7528 else
7533 -- Special processing for Enabled attribute. This attribute has a very
7534 -- special prefix, and the easiest way to avoid lots of special checks
7535 -- to protect this special prefix from causing trouble is to deal with
7536 -- this attribute immediately and be done with it.
7540 -- We skip evaluation if the expander is not active. This is not just
7541 -- an optimization. It is of key importance that we not rewrite the
7542 -- attribute in a generic template, since we want to pick up the
7543 -- setting of the check in the instance, Testing Expander_Active
7544 -- might seem an easy way of doing this, but we need to account for
7545 -- ASIS needs, so check explicitly for a generic context.
7548 declare
7552 begin
7556 else
7560 else
7571 -- Attribute 'Img applied to a static enumeration value is static, and
7572 -- we will do the folding right here (things get confused if we let this
7573 -- case go through the normal circuitry).
7579 then
7580 declare
7584 begin
7585 Start_String;
7599 -- Special processing for cases where the prefix is an object. For this
7600 -- purpose, a string literal counts as an object (attributes of string
7601 -- literals can only appear in generated code).
7605 -- For Component_Size, the prefix is an array object, and we apply
7606 -- the attribute to the type of the object. This is allowed for both
7607 -- unconstrained and constrained arrays, since the bounds have no
7608 -- influence on the value of this attribute.
7613 -- For Enum_Rep, evaluation depends on the nature of the prefix and
7614 -- the optional argument.
7619 declare
7621 -- The enumeration-type expression of interest
7623 begin
7624 -- P'Enum_Rep case
7627 E_Enumeration_Literal)
7628 then
7631 -- Enum_Type'Enum_Rep (E1) case
7636 -- Otherwise the attribute must be expanded into a
7637 -- conversion and evaluated at run time.
7639 else
7640 Check_Expressions;
7644 -- We can fold if the expression is an enumeration
7645 -- literal, or if it denotes a constant whose value
7646 -- is known at compile time.
7650 E_Enumeration_Literal
7651 or else
7654 N_Object_Declaration
7655 and then Compile_Time_Known_Value
7657 then
7659 else
7660 Check_Expressions;
7665 -- Otherwise the attribute is illegal, do not attempt to perform
7666 -- any kind of folding.
7668 else
7672 -- For First and Last, the prefix is an array object, and we apply
7673 -- the attribute to the type of the array, but we need a constrained
7674 -- type for this, so we use the actual subtype if available.
7678 Id = Attribute_Length
7679 then
7680 declare
7683 begin
7687 -- If we have an unconstrained type we cannot fold
7689 else
7690 Check_Expressions;
7695 -- For Size, give size of object if available, otherwise we
7696 -- cannot fold Size.
7701 then
7705 else
7706 Check_Expressions;
7710 -- For Alignment, give size of object if available, otherwise we
7711 -- cannot fold Alignment.
7716 then
7720 else
7721 Check_Expressions;
7725 -- For Lock_Free, we apply the attribute to the type of the object.
7726 -- This is allowed since we have already verified that the type is a
7727 -- protected type.
7732 -- No other attributes for objects are folded
7734 else
7735 Check_Expressions;
7739 -- Cases where P is not an object. Cannot do anything if P is not the
7740 -- name of an entity.
7743 Check_Expressions;
7746 -- Otherwise get prefix entity
7748 else
7752 -- If we are asked to evaluate an attribute where the prefix is a
7753 -- non-frozen generic actual type whose RM_Size is still set to zero,
7754 -- then abandon the effort.
7761 -- However, the attribute Unconstrained_Array must be evaluated,
7762 -- since it is documented to be a static attribute (and can for
7763 -- example appear in a Compile_Time_Warning pragma). The frozen
7764 -- status of the type does not affect its evaluation.
7767 then
7771 -- At this stage P_Entity is the entity to which the attribute
7772 -- is to be applied. This is usually simply the entity of the
7773 -- prefix, except in some cases of attributes for objects, where
7774 -- as described above, we apply the attribute to the object type.
7776 -- Here is where we make sure that static attributes are properly
7777 -- marked as such. These are attributes whose prefix is a static
7778 -- scalar subtype, whose result is scalar, and whose arguments, if
7779 -- present, are static scalar expressions. Note that such references
7780 -- are static expressions even if they raise Constraint_Error.
7782 -- For example, Boolean'Pos (1/0 = 0) is a static expression, even
7783 -- though evaluating it raises constraint error. This means that a
7784 -- declaration like:
7786 -- X : constant := (if True then 1 else Boolean'Pos (1/0 = 0));
7788 -- is legal, since here this expression appears in a statically
7789 -- unevaluated position, so it does not actually raise an exception.
7795 and then
7799 and then
7803 then
7808 -- First foldable possibility is a scalar or array type (RM 4.9(7))
7809 -- that is not generic (generic types are eliminated by RM 4.9(25)).
7810 -- Note we allow non-static non-generic types at this stage as further
7811 -- described below.
7816 then
7819 -- Second foldable possibility is an array object (RM 4.9(8))
7824 then
7827 -- If the entity is an array constant with an unconstrained nominal
7828 -- subtype then get the type from the initial value. If the value has
7829 -- been expanded into assignments, there is no expression and the
7830 -- attribute reference remains dynamic.
7832 -- We could do better here and retrieve the type ???
7836 then
7839 else
7844 -- Definite must be folded if the prefix is not a generic type, that
7845 -- is to say if we are within an instantiation. Same processing applies
7846 -- to the GNAT attributes Atomic_Always_Lock_Free, Has_Discriminants,
7847 -- Lock_Free, Type_Class, Has_Tagged_Value, and Unconstrained_Array.
7859 then
7862 -- We can fold 'Size applied to a type if the size is known (as happens
7863 -- for a size from an attribute definition clause). At this stage, this
7864 -- can happen only for types (e.g. record types) for which the size is
7865 -- always non-static. We exclude generic types from consideration (since
7866 -- they have bogus sizes set within templates).
7872 then
7876 -- We can fold 'Alignment applied to a type if the alignment is known
7877 -- (as happens for an alignment from an attribute definition clause).
7878 -- At this stage, this can happen only for types (e.g. record types) for
7879 -- which the size is always non-static. We exclude generic types from
7880 -- consideration (since they have bogus sizes set within templates).
7886 then
7890 -- If this is an access attribute that is known to fail accessibility
7891 -- check, rewrite accordingly.
7895 then
7902 -- No other cases are foldable (they certainly aren't static, and at
7903 -- the moment we don't try to fold any cases other than the ones above).
7905 else
7906 Check_Expressions;
7910 -- If either attribute or the prefix is Any_Type, then propagate
7911 -- Any_Type to the result and don't do anything else at all.
7916 then
7921 -- Scalar subtype case. We have not yet enforced the static requirement
7922 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
7923 -- of non-static attribute references (e.g. S'Digits for a non-static
7924 -- floating-point type, which we can compute at compile time).
7926 -- Note: this folding of non-static attributes is not simply a case of
7927 -- optimization. For many of the attributes affected, Gigi cannot handle
7928 -- the attribute and depends on the front end having folded them away.
7930 -- Note: although we don't require staticness at this stage, we do set
7931 -- the Static variable to record the staticness, for easy reference by
7932 -- those attributes where it matters (e.g. Succ and Pred), and also to
7933 -- be used to ensure that non-static folded things are not marked as
7934 -- being static (a check that is done right at the end).
7939 -- If the root type or base type is generic, then we cannot fold. This
7940 -- test is needed because subtypes of generic types are not always
7941 -- marked as being generic themselves (which seems odd???)
7945 then
7957 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
7958 -- since we can't do anything with unconstrained arrays. In addition,
7959 -- only the First, Last and Length attributes are possibly static.
7961 -- Atomic_Always_Lock_Free, Definite, Has_Access_Values,
7962 -- Has_Discriminants, Has_Tagged_Values, Lock_Free, Type_Class, and
7963 -- Unconstrained_Array are again exceptions, because they apply as well
7964 -- to unconstrained types.
7966 -- In addition Component_Size is an exception since it is possibly
7967 -- foldable, even though it is never static, and it does apply to
7968 -- unconstrained arrays. Furthermore, it is essential to fold this
7969 -- in the packed case, since otherwise the value will be incorrect.
7979 Id = Attribute_Component_Size
7980 then
7989 then
7990 Check_Expressions;
7994 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
7995 -- scalar case, we hold off on enforcing staticness, since there are
7996 -- cases which we can fold at compile time even though they are not
7997 -- static (e.g. 'Length applied to a static index, even though other
7998 -- non-static indexes make the array type non-static). This is only
7999 -- an optimization, but it falls out essentially free, so why not.
8000 -- Again we compute the variable Static for easy reference later
8001 -- (note that no array attributes are static in Ada 83).
8003 -- We also need to set Static properly for subsequent legality checks
8004 -- which might otherwise accept non-static constants in contexts
8005 -- where they are not legal.
8007 Static :=
8011 declare
8014 begin
8017 -- The expression is static if the array type is constrained
8018 -- by given bounds, and not by an initial expression. Constant
8019 -- strings are static in any case.
8022 Static :=
8038 -- If however the index type is generic, or derived from
8039 -- one, attributes cannot be folded.
8043 then
8052 -- Check any expressions that are present. Note that these expressions,
8053 -- depending on the particular attribute type, are either part of the
8054 -- attribute designator, or they are arguments in a case where the
8055 -- attribute reference returns a function. In the latter case, the
8056 -- rule in (RM 4.9(22)) applies and in particular requires the type
8057 -- of the expressions to be scalar in order for the attribute to be
8058 -- considered to be static.
8060 declare
8063 begin
8068 -- If expression is not static, then the attribute reference
8069 -- result certainly cannot be static.
8080 -- If the result is not known at compile time, or is not of
8081 -- a scalar type, then the result is definitely not static,
8082 -- so we can quit now.
8086 then
8087 -- An odd special case, if this is a Pos attribute, this
8088 -- is where we need to apply a range check since it does
8089 -- not get done anywhere else.
8097 Check_Expressions;
8100 -- If the expression raises a constraint error, then so does
8101 -- the attribute reference. We keep going in this case because
8102 -- we are still interested in whether the attribute reference
8103 -- is static even if it is not static.
8118 -- Deal with the case of a static attribute reference that raises
8119 -- constraint error. The Raises_Constraint_Error flag will already
8120 -- have been set, and the Static flag shows whether the attribute
8121 -- reference is static. In any case we certainly can't fold such an
8122 -- attribute reference.
8124 -- Note that the rewriting of the attribute node with the constraint
8125 -- error node is essential in this case, because otherwise Gigi might
8126 -- blow up on one of the attributes it never expects to see.
8128 -- The constraint_error node must have the type imposed by the context,
8129 -- to avoid spurious errors in the enclosing expression.
8132 CE_Node :=
8137 Check_Expressions;
8143 -- At this point we have a potentially foldable attribute reference.
8144 -- If Static is set, then the attribute reference definitely obeys
8145 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
8146 -- folded. If Static is not set, then the attribute may or may not
8147 -- be foldable, and the individual attribute processing routines
8148 -- test Static as required in cases where it makes a difference.
8150 -- In the case where Static is not set, we do know that all the
8151 -- expressions present are at least known at compile time (we assumed
8152 -- above that if this was not the case, then there was no hope of static
8153 -- evaluation). However, we did not require that the bounds of the
8154 -- prefix type be compile time known, let alone static). That's because
8155 -- there are many attributes that can be computed at compile time on
8156 -- non-static subtypes, even though such references are not static
8157 -- expressions.
8159 -- For VAX float, the root type is an IEEE type. So make sure to use the
8160 -- base type instead of the root-type for floating point attributes.
8164 -- Attributes related to Ada 2012 iterators; nothing to evaluate for
8165 -- these.
8167 when Attribute_Constant_Indexing
8168 | Attribute_Default_Iterator
8169 | Attribute_Implicit_Dereference
8170 | Attribute_Iterator_Element
8171 | Attribute_Iterable
8172 | Attribute_Variable_Indexing
8173 =>
8176 -- Internal attributes used to deal with Ada 2012 delayed aspects.
8177 -- These were already rejected by the parser. Thus they shouldn't
8178 -- appear here.
8183 --------------
8184 -- Adjacent --
8185 --------------
8188 Fold_Ureal
8190 Eval_Fat.Adjacent
8192 Static);
8194 ---------
8195 -- Aft --
8196 ---------
8201 ---------------
8202 -- Alignment --
8203 ---------------
8208 begin
8209 -- Fold if alignment is set and not otherwise
8216 -----------------------------
8217 -- Atomic_Always_Lock_Free --
8218 -----------------------------
8220 -- Atomic_Always_Lock_Free attribute is a Boolean, thus no need to fold
8221 -- here.
8224 declare
8226 Boolean_Literals
8227 (Support_Atomic_Primitives_On_Target
8230 begin
8233 -- Analyze and resolve as boolean. Note that this attribute is a
8234 -- static attribute in GNAT.
8241 ---------
8242 -- Bit --
8243 ---------
8245 -- Bit can never be folded
8250 ------------------
8251 -- Body_Version --
8252 ------------------
8254 -- Body_version can never be static
8259 -------------
8260 -- Ceiling --
8261 -------------
8264 Fold_Ureal
8267 --------------------
8268 -- Component_Size --
8269 --------------------
8276 -------------
8277 -- Compose --
8278 -------------
8281 Fold_Ureal
8284 Static);
8286 -----------------
8287 -- Constrained --
8288 -----------------
8290 -- Constrained is never folded for now, there may be cases that
8291 -- could be handled at compile time. To be looked at later.
8295 -- The expander might fold it and set the static flag accordingly,
8296 -- but with expansion disabled (as in ASIS), it remains as an
8297 -- attribute reference, and this reference is not static.
8302 ---------------
8303 -- Copy_Sign --
8304 ---------------
8307 Fold_Ureal
8309 Eval_Fat.Copy_Sign
8311 Static);
8313 --------------
8314 -- Definite --
8315 --------------
8322 -----------
8323 -- Delta --
8324 -----------
8329 ------------
8330 -- Denorm --
8331 ------------
8334 Fold_Uint
8337 ---------------------
8338 -- Descriptor_Size --
8339 ---------------------
8344 ------------
8345 -- Digits --
8346 ------------
8351 ----------
8352 -- Emax --
8353 ----------
8357 -- Ada 83 attribute is defined as (RM83 3.5.8)
8359 -- T'Emax = 4 * T'Mantissa
8363 --------------
8364 -- Enum_Rep --
8365 --------------
8370 begin
8371 -- The attribute appears in the form:
8373 -- Enum_Typ'Enum_Rep (Const)
8374 -- Enum_Typ'Enum_Rep (Enum_Lit)
8379 -- Otherwise the prefix denotes a constant or enumeration literal:
8381 -- Const'Enum_Rep
8382 -- Enum_Lit'Enum_Rep
8384 else
8388 -- For an enumeration type with a non-standard representation use
8389 -- the Enumeration_Rep field of the proper constant. Note that this
8390 -- will not work for types Character/Wide_[Wide-]Character, since no
8391 -- real entities are created for the enumeration literals, but that
8392 -- does not matter since these two types do not have non-standard
8393 -- representations anyway.
8397 then
8400 -- For enumeration types with standard representations and all other
8401 -- cases (i.e. all integer and modular types), Enum_Rep is equivalent
8402 -- to Pos.
8404 else
8409 --------------
8410 -- Enum_Val --
8411 --------------
8416 begin
8417 -- We have something like Enum_Type'Enum_Val (23), so search for a
8418 -- corresponding value in the list of Enum_Rep values for the type.
8421 loop
8430 Apply_Compile_Time_Constraint_Error
8432 CE_Range_Check_Failed,
8439 -------------
8440 -- Epsilon --
8441 -------------
8445 -- Ada 83 attribute is defined as (RM83 3.5.8)
8447 -- T'Epsilon = 2.0**(1 - T'Mantissa)
8451 --------------
8452 -- Exponent --
8453 --------------
8459 -----------------------
8460 -- Finalization_Size --
8461 -----------------------
8466 -----------
8467 -- First --
8468 -----------
8471 Set_Bounds;
8476 else
8480 else
8484 -----------------
8485 -- First_Valid --
8486 -----------------
8491 then
8492 declare
8495 begin
8498 else
8503 else
8504 Set_Bounds;
8508 -----------------
8509 -- Fixed_Value --
8510 -----------------
8515 -----------
8516 -- Floor --
8517 -----------
8520 Fold_Ureal
8523 ----------
8524 -- Fore --
8525 ----------
8532 --------------
8533 -- Fraction --
8534 --------------
8537 Fold_Ureal
8540 -----------------------
8541 -- Has_Access_Values --
8542 -----------------------
8549 -----------------------
8550 -- Has_Discriminants --
8551 -----------------------
8558 ----------------------
8559 -- Has_Same_Storage --
8560 ----------------------
8565 -----------------------
8566 -- Has_Tagged_Values --
8567 -----------------------
8574 --------------
8575 -- Identity --
8576 --------------
8581 -----------
8582 -- Image --
8583 -----------
8585 -- Image is a scalar attribute, but is never static, because it is
8586 -- not a static function (having a non-scalar argument (RM 4.9(22))
8587 -- However, we can constant-fold the image of an enumeration literal
8588 -- if names are available.
8594 and then not Global_Discard_Names
8595 then
8596 declare
8599 begin
8600 Start_String;
8611 -------------------
8612 -- Integer_Value --
8613 -------------------
8615 -- We never try to fold Integer_Value (though perhaps we could???)
8620 -------------------
8621 -- Invalid_Value --
8622 -------------------
8624 -- Invalid_Value is a scalar attribute that is never static, because
8625 -- the value is by design out of range.
8630 -----------
8631 -- Large --
8632 -----------
8636 -- For fixed-point, we use the identity:
8638 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
8643 Left_Opnd =>
8645 Left_Opnd =>
8647 Left_Opnd =>
8649 Right_Opnd =>
8655 Right_Opnd =>
8660 -- Floating-point (Ada 83 compatibility)
8662 else
8663 -- Ada 83 attribute is defined as (RM83 3.5.8)
8665 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
8667 -- where
8669 -- T'Emax = 4 * T'Mantissa
8671 Fold_Ureal
8677 ---------------
8678 -- Lock_Free --
8679 ---------------
8684 begin
8687 -- Analyze and resolve as boolean. Note that this attribute is a
8688 -- static attribute in GNAT.
8695 ----------
8696 -- Last --
8697 ----------
8700 Set_Bounds;
8705 else
8709 else
8713 ----------------
8714 -- Last_Valid --
8715 ----------------
8720 then
8721 declare
8724 begin
8727 else
8732 else
8733 Set_Bounds;
8737 ------------------
8738 -- Leading_Part --
8739 ------------------
8742 Fold_Ureal
8744 Eval_Fat.Leading_Part
8746 Static);
8748 ------------
8749 -- Length --
8750 ------------
8755 begin
8756 -- If any index type is a formal type, or derived from one, the
8757 -- bounds are not static. Treating them as static can produce
8758 -- spurious warnings or improper constant folding.
8769 Set_Bounds;
8771 -- For two compile time values, we can compute length
8775 then
8778 Static);
8781 -- One more case is where Hi_Bound and Lo_Bound are compile-time
8782 -- comparable, and we can figure out the difference between them.
8784 declare
8787 begin
8788 case
8789 Compile_Time_Compare
8791 is
8809 ----------------
8810 -- Loop_Entry --
8811 ----------------
8813 -- Loop_Entry acts as an alias of a constant initialized to the prefix
8814 -- of the said attribute at the point of entry into the related loop. As
8815 -- such, the attribute reference does not need to be evaluated because
8816 -- the prefix is the one that is evaluted.
8821 -------------
8822 -- Machine --
8823 -------------
8826 Fold_Ureal
8828 Eval_Fat.Machine
8830 Static);
8832 ------------------
8833 -- Machine_Emax --
8834 ------------------
8839 ------------------
8840 -- Machine_Emin --
8841 ------------------
8846 ----------------------
8847 -- Machine_Mantissa --
8848 ----------------------
8853 -----------------------
8854 -- Machine_Overflows --
8855 -----------------------
8859 -- Always true for fixed-point
8864 -- Floating point case
8866 else
8869 Static);
8872 -------------------
8873 -- Machine_Radix --
8874 -------------------
8880 then
8882 else
8886 -- All floating-point type always have radix 2
8888 else
8892 ----------------------
8893 -- Machine_Rounding --
8894 ----------------------
8896 -- Note: for the folding case, it is fine to treat Machine_Rounding
8897 -- exactly the same way as Rounding, since this is one of the allowed
8898 -- behaviors, and performance is not an issue here. It might be a bit
8899 -- better to give the same result as it would give at run time, even
8900 -- though the non-determinism is certainly permitted.
8903 Fold_Ureal
8906 --------------------
8907 -- Machine_Rounds --
8908 --------------------
8912 -- Always False for fixed-point
8917 -- Else yield proper floating-point result
8919 else
8920 Fold_Uint
8922 Static);
8925 ------------------
8926 -- Machine_Size --
8927 ------------------
8929 -- Note: Machine_Size is identical to Object_Size
8934 begin
8940 --------------
8941 -- Mantissa --
8942 --------------
8946 -- Fixed-point mantissa
8950 -- Compile time foldable case
8953 and then
8955 then
8956 -- The calculation of the obsolete Ada 83 attribute Mantissa
8957 -- is annoying, because of AI00143, quoted here:
8959 -- !question 84-01-10
8961 -- Consider the model numbers for F:
8963 -- type F is delta 1.0 range -7.0 .. 8.0;
8965 -- The wording requires that F'MANTISSA be the SMALLEST
8966 -- integer number for which each bound of the specified
8967 -- range is either a model number or lies at most small
8968 -- distant from a model number. This means F'MANTISSA
8969 -- is required to be 3 since the range -7.0 .. 7.0 fits
8970 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
8971 -- number, namely, 7. Is this analysis correct? Note that
8972 -- this implies the upper bound of the range is not
8973 -- represented as a model number.
8975 -- !response 84-03-17
8977 -- The analysis is correct. The upper and lower bounds for
8978 -- a fixed point type can lie outside the range of model
8979 -- numbers.
8981 declare
8988 begin
8994 -- If the Bound is exactly a model number, i.e. a multiple
8995 -- of Small, then we back it off by one to get the integer
8996 -- value that must be representable.
9002 -- Now find corresponding size = Mantissa value
9012 else
9013 -- The case of dynamic bounds cannot be evaluated at compile
9014 -- time. Instead we use a runtime routine (see Exp_Attr).
9019 -- Floating-point Mantissa
9021 else
9025 ---------
9026 -- Max --
9027 ---------
9031 Fold_Ureal
9033 else
9037 ----------------------------------
9038 -- Max_Alignment_For_Allocation --
9039 ----------------------------------
9041 -- Max_Alignment_For_Allocation is usually the Alignment. However,
9042 -- arrays are allocated with dope, so we need to take into account both
9043 -- the alignment of the array, which comes from the component alignment,
9044 -- and the alignment of the dope. Also, if the alignment is unknown, we
9045 -- use the max (it's OK to be pessimistic).
9049 begin
9052 then
9059 ----------------------------------
9060 -- Max_Size_In_Storage_Elements --
9061 ----------------------------------
9063 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
9064 -- Storage_Unit boundary. We can fold any cases for which the size
9065 -- is known by the front end.
9071 System_Storage_Unit,
9072 Static);
9075 --------------------
9076 -- Mechanism_Code --
9077 --------------------
9084 begin
9088 else
9104 ---------
9105 -- Min --
9106 ---------
9110 Fold_Ureal
9112 else
9113 Fold_Uint
9117 ---------
9118 -- Mod --
9119 ---------
9122 Fold_Uint
9125 -----------
9126 -- Model --
9127 -----------
9130 Fold_Ureal
9133 ----------------
9134 -- Model_Emin --
9135 ----------------
9140 -------------------
9141 -- Model_Epsilon --
9142 -------------------
9147 --------------------
9148 -- Model_Mantissa --
9149 --------------------
9154 -----------------
9155 -- Model_Small --
9156 -----------------
9161 -------------
9162 -- Modulus --
9163 -------------
9168 --------------------
9169 -- Null_Parameter --
9170 --------------------
9172 -- Cannot fold, we know the value sort of, but the whole point is
9173 -- that there is no way to talk about this imaginary value except
9174 -- by using the attribute, so we leave it the way it is.
9179 -----------------
9180 -- Object_Size --
9181 -----------------
9183 -- The Object_Size attribute for a type returns the Esize of the
9184 -- type and can be folded if this value is known.
9189 begin
9195 ----------------------
9196 -- Overlaps_Storage --
9197 ----------------------
9202 -------------------------
9203 -- Passed_By_Reference --
9204 -------------------------
9206 -- Scalar types are never passed by reference
9211 ---------
9212 -- Pos --
9213 ---------
9218 ----------
9219 -- Pred --
9220 ----------
9224 -- Floating-point case
9227 Fold_Ureal
9230 -- Fixed-point case
9233 Fold_Ureal
9236 -- Modular integer case (wraps)
9241 -- Other scalar cases
9243 else
9249 then
9250 Apply_Compile_Time_Constraint_Error
9252 CE_Overflow_Check_Failed,
9256 Check_Expressions;
9263 -----------
9264 -- Range --
9265 -----------
9267 -- No processing required, because by this stage, Range has been
9268 -- replaced by First .. Last, so this branch can never be taken.
9273 ------------------
9274 -- Range_Length --
9275 ------------------
9280 begin
9281 Set_Bounds;
9283 -- Can fold if both bounds are compile time known
9287 then
9289 UI_Max
9291 Static);
9294 -- One more case is where Hi_Bound and Lo_Bound are compile-time
9295 -- comparable, and we can figure out the difference between them.
9297 case Compile_Time_Compare
9299 is
9316 ---------
9317 -- Ref --
9318 ---------
9323 ---------------
9324 -- Remainder --
9325 ---------------
9331 begin
9333 Apply_Compile_Time_Constraint_Error
9335 CE_Overflow_Check_Failed,
9338 Check_Expressions;
9345 -----------------
9346 -- Restriction --
9347 -----------------
9353 -----------
9354 -- Round --
9355 -----------
9361 begin
9362 -- First we get the (exact result) in units of small
9366 -- Now round that exactly to an integer
9370 -- Finally the result is obtained by converting back to real
9375 --------------
9376 -- Rounding --
9377 --------------
9380 Fold_Ureal
9383 ---------------
9384 -- Safe_Emax --
9385 ---------------
9390 ----------------
9391 -- Safe_First --
9392 ----------------
9397 ----------------
9398 -- Safe_Large --
9399 ----------------
9403 Fold_Ureal
9405 else
9409 ---------------
9410 -- Safe_Last --
9411 ---------------
9416 ----------------
9417 -- Safe_Small --
9418 ----------------
9422 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
9423 -- for fixed-point, since is the same as Small, but we implement
9424 -- it for backwards compatibility.
9429 -- Ada 83 Safe_Small for floating-point cases
9431 else
9435 -----------
9436 -- Scale --
9437 -----------
9442 -------------
9443 -- Scaling --
9444 -------------
9447 Fold_Ureal
9449 Eval_Fat.Scaling
9451 Static);
9453 ------------------
9454 -- Signed_Zeros --
9455 ------------------
9458 Fold_Uint
9461 ----------
9462 -- Size --
9463 ----------
9465 -- Size attribute returns the RM size. All scalar types can be folded,
9466 -- as well as any types for which the size is known by the front end,
9467 -- including any type for which a size attribute is specified. This is
9468 -- one of the places where it is annoying that a size of zero means two
9469 -- things (zero size for scalars, unspecified size for non-scalars).
9471 when Attribute_Size
9472 | Attribute_VADS_Size
9473 =>
9477 begin
9480 then
9481 -- VADS_Size case
9484 declare
9487 begin
9488 -- If a size clause applies, then use the size from it.
9489 -- This is one of the rare cases where we can use the
9490 -- Size_Clause field for a subtype when Has_Size_Clause
9491 -- is False. Consider:
9493 -- type x is range 1 .. 64;
9494 -- for x'size use 12;
9495 -- subtype y is x range 0 .. 3;
9497 -- Here y has a size clause inherited from x, but
9498 -- normally it does not apply, and y'size is 2. However,
9499 -- y'VADS_Size is indeed 12 and not 2.
9503 then
9506 -- If no size is specified, then we simply use the object
9507 -- size in the VADS_Size case (e.g. Natural'Size is equal
9508 -- to Integer'Size, not one less).
9510 else
9515 -- Normal case (Size) in which case we want the RM_Size
9517 else
9523 -----------
9524 -- Small --
9525 -----------
9529 -- The floating-point case is present only for Ada 83 compatibility.
9530 -- Note that strictly this is an illegal addition, since we are
9531 -- extending an Ada 95 defined attribute, but we anticipate an
9532 -- ARG ruling that will permit this.
9536 -- Ada 83 attribute is defined as (RM83 3.5.8)
9538 -- T'Small = 2.0**(-T'Emax - 1)
9540 -- where
9542 -- T'Emax = 4 * T'Mantissa
9546 -- Normal Ada 95 fixed-point case
9548 else
9552 -----------------
9553 -- Stream_Size --
9554 -----------------
9559 ----------
9560 -- Succ --
9561 ----------
9564 -- Floating-point case
9567 Fold_Ureal
9570 -- Fixed-point case
9575 -- Modular integer case (wraps)
9580 -- Other scalar cases
9582 else
9588 then
9589 Apply_Compile_Time_Constraint_Error
9591 CE_Overflow_Check_Failed,
9595 Check_Expressions;
9597 else
9602 ----------------
9603 -- Truncation --
9604 ----------------
9607 Fold_Ureal
9610 Static);
9612 ----------------
9613 -- Type_Class --
9614 ----------------
9620 begin
9648 -- We treat protected types like task types. It would make more
9649 -- sense to have another enumeration value, but after all the
9650 -- whole point of this feature is to be exactly DEC compatible,
9651 -- and changing the type Type_Class would not meet this requirement.
9656 -- Not clear if there are any other possibilities, but if there
9657 -- are, then we will treat them as the address case.
9659 else
9666 -----------------------
9667 -- Unbiased_Rounding --
9668 -----------------------
9671 Fold_Ureal
9674 Static);
9676 -------------------------
9677 -- Unconstrained_Array --
9678 -------------------------
9683 begin
9685 Boolean_Literals (
9689 -- Analyze and resolve as boolean, note that this attribute is
9690 -- a static attribute in GNAT.
9697 -- Attribute Update is never static
9702 ---------------
9703 -- VADS_Size --
9704 ---------------
9706 -- Processing is shared with Size
9708 ---------
9709 -- Val --
9710 ---------
9714 or else
9716 then
9717 Apply_Compile_Time_Constraint_Error
9719 CE_Range_Check_Failed,
9722 Check_Expressions;
9725 else
9729 ----------------
9730 -- Value_Size --
9731 ----------------
9733 -- The Value_Size attribute for a type returns the RM size of the type.
9734 -- This an always be folded for scalar types, and can also be folded for
9735 -- non-scalar types if the size is set. This is one of the places where
9736 -- it is annoying that a size of zero means two things!
9741 begin
9747 -------------
9748 -- Version --
9749 -------------
9751 -- Version can never be static
9756 ----------------
9757 -- Wide_Image --
9758 ----------------
9760 -- Wide_Image is a scalar attribute, but is never static, because it
9761 -- is not a static function (having a non-scalar argument (RM 4.9(22))
9766 ---------------------
9767 -- Wide_Wide_Image --
9768 ---------------------
9770 -- Wide_Wide_Image is a scalar attribute but is never static, because it
9771 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
9776 ---------------------
9777 -- Wide_Wide_Width --
9778 ---------------------
9780 -- Processing for Wide_Wide_Width is combined with Width
9782 ----------------
9783 -- Wide_Width --
9784 ----------------
9786 -- Processing for Wide_Width is combined with Width
9788 -----------
9789 -- Width --
9790 -----------
9792 -- This processing also handles the case of Wide_[Wide_]Width
9794 when Attribute_Width
9795 | Attribute_Wide_Width
9796 | Attribute_Wide_Wide_Width
9797 =>
9800 -- Floating-point types
9804 -- Width is zero for a null range (RM 3.5 (38))
9808 then
9811 else
9812 -- For floating-point, we have +N.dddE+nnn where length
9813 -- of ddd is determined by type'Digits - 1, but is one
9814 -- if Digits is one (RM 3.5 (33)).
9816 -- nnn is set to 2 for Short_Float and Float (32 bit
9817 -- floats), and 3 for Long_Float and Long_Long_Float.
9818 -- For machines where Long_Long_Float is the IEEE
9819 -- extended precision type, the exponent takes 4 digits.
9821 declare
9825 begin
9830 else
9838 -- Fixed-point types
9842 -- Width is zero for a null range (RM 3.5 (38))
9846 then
9849 -- The non-null case depends on the specific real type
9851 else
9852 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
9854 Fold_Uint
9856 Static);
9859 -- Discrete types
9861 else
9862 declare
9872 begin
9873 -- Empty ranges
9878 -- Width for types derived from Standard.Character
9879 -- and Standard.Wide_[Wide_]Character.
9884 -- Set W larger if needed
9888 -- All wide characters look like Hex_hhhhhhhh
9892 -- No need to compute this more than once
9896 else
9899 -- Test for all cases where Character'Image
9900 -- yields an image that is longer than three
9901 -- characters. First the cases of Reserved_xxx
9902 -- names (length = 12).
9905 when Reserved_128
9906 | Reserved_129
9907 | Reserved_132
9908 | Reserved_153
9909 =>
9912 when BS
9913 | CR
9914 | EM
9915 | FF
9916 | FS
9917 | GS
9918 | HT
9919 | LF
9920 | MW
9921 | PM
9922 | RI
9923 | RS
9924 | SI
9925 | SO
9926 | ST
9927 | US
9928 | VT
9929 =>
9932 when ACK
9933 | APC
9934 | BEL
9935 | BPH
9936 | CAN
9937 | CCH
9938 | CSI
9939 | DC1
9940 | DC2
9941 | DC3
9942 | DC4
9943 | DCS
9944 | DEL
9945 | DLE
9946 | ENQ
9947 | EOT
9948 | EPA
9949 | ESA
9950 | ESC
9951 | ETB
9952 | ETX
9953 | HTJ
9954 | HTS
9955 | NAK
9956 | NBH
9957 | NEL
9958 | NUL
9959 | OSC
9960 | PLD
9961 | PLU
9962 | PU1
9963 | PU2
9964 | SCI
9965 | SOH
9966 | SOS
9967 | SPA
9968 | SS2
9969 | SS3
9970 | SSA
9971 | STS
9972 | STX
9973 | SUB
9974 | SYN
9975 | VTS
9976 =>
9980 | No_Break_Space .. LC_Y_Diaeresis
9981 =>
9982 -- Special case of soft hyphen in Ada 2005
9986 then
9988 else
9997 -- Width for types derived from Standard.Boolean
10002 else
10006 -- Width for integer types
10017 -- User declared enum type with discard names
10021 -- If range is null, result is zero, that has already
10022 -- been dealt with, so what we need is the power of ten
10023 -- that accommodates the Pos of the largest value, which
10024 -- is the high bound of the range + one for the space.
10033 -- Only remaining possibility is user declared enum type
10034 -- with normal case of Discard_Names not active.
10036 else
10043 -- Only pay attention to in range characters
10047 then
10048 -- For Width case, use decoded name
10054 -- For Wide_[Wide_]Width, use encoded name, and
10055 -- then adjust for the encoding.
10057 else
10060 -- Character literals are always of length 3
10065 -- Otherwise loop to adjust for upper/wide chars
10067 else
10092 -- The following attributes denote functions that cannot be folded
10094 when Attribute_From_Any
10095 | Attribute_To_Any
10096 | Attribute_TypeCode
10097 =>
10100 -- The following attributes can never be folded, and furthermore we
10101 -- should not even have entered the case statement for any of these.
10102 -- Note that in some cases, the values have already been folded as
10103 -- a result of the processing in Analyze_Attribute or earlier in
10104 -- this procedure.
10106 when Attribute_Abort_Signal
10107 | Attribute_Access
10108 | Attribute_Address
10109 | Attribute_Address_Size
10110 | Attribute_Asm_Input
10111 | Attribute_Asm_Output
10112 | Attribute_Base
10113 | Attribute_Bit_Order
10114 | Attribute_Bit_Position
10115 | Attribute_Callable
10116 | Attribute_Caller
10117 | Attribute_Class
10118 | Attribute_Code_Address
10119 | Attribute_Compiler_Version
10120 | Attribute_Count
10121 | Attribute_Default_Bit_Order
10122 | Attribute_Default_Scalar_Storage_Order
10123 | Attribute_Deref
10124 | Attribute_Elaborated
10125 | Attribute_Elab_Body
10126 | Attribute_Elab_Spec
10127 | Attribute_Elab_Subp_Body
10128 | Attribute_Enabled
10129 | Attribute_External_Tag
10130 | Attribute_Fast_Math
10131 | Attribute_First_Bit
10132 | Attribute_Img
10133 | Attribute_Input
10134 | Attribute_Last_Bit
10135 | Attribute_Library_Level
10136 | Attribute_Maximum_Alignment
10137 | Attribute_Old
10138 | Attribute_Output
10139 | Attribute_Partition_ID
10140 | Attribute_Pool_Address
10141 | Attribute_Position
10142 | Attribute_Priority
10143 | Attribute_Read
10144 | Attribute_Result
10145 | Attribute_Scalar_Storage_Order
10146 | Attribute_Simple_Storage_Pool
10147 | Attribute_Storage_Pool
10148 | Attribute_Storage_Size
10149 | Attribute_Storage_Unit
10150 | Attribute_Stub_Type
10151 | Attribute_System_Allocator_Alignment
10152 | Attribute_Tag
10153 | Attribute_Target_Name
10154 | Attribute_Terminated
10155 | Attribute_To_Address
10156 | Attribute_Type_Key
10157 | Attribute_Unchecked_Access
10158 | Attribute_Universal_Literal_String
10159 | Attribute_Unrestricted_Access
10160 | Attribute_Valid
10161 | Attribute_Valid_Scalars
10162 | Attribute_Value
10163 | Attribute_Wchar_T_Size
10164 | Attribute_Wide_Value
10165 | Attribute_Wide_Wide_Value
10166 | Attribute_Word_Size
10167 | Attribute_Write
10168 =>
10172 -- At the end of the case, one more check. If we did a static evaluation
10173 -- so that the result is now a literal, then set Is_Static_Expression
10174 -- in the constant only if the prefix type is a static subtype. For
10175 -- non-static subtypes, the folding is still OK, but not static.
10177 -- An exception is the GNAT attribute Constrained_Array which is
10178 -- defined to be a static attribute in all cases.
10181 N_Real_Literal,
10182 N_Character_Literal,
10183 N_String_Literal)
10186 then
10189 -- If this is still an attribute reference, then it has not been folded
10190 -- and that means that its expressions are in a non-static context.
10193 Check_Expressions;
10195 -- Note: the else case not covered here are odd cases where the
10196 -- processing has transformed the attribute into something other
10197 -- than a constant. Nothing more to do in such cases.
10199 else
10204 ------------------------------
10205 -- Is_Anonymous_Tagged_Base --
10206 ------------------------------
10208 function Is_Anonymous_Tagged_Base
10211 is
10212 begin
10213 return
10214 Anon = Current_Scope
10219 --------------------------------
10220 -- Name_Implies_Lvalue_Prefix --
10221 --------------------------------
10225 begin
10229 -----------------------
10230 -- Resolve_Attribute --
10231 -----------------------
10245 -- Error, or warning within an instance, if the static accessibility
10246 -- rules of 3.10.2 are violated.
10248 function Declared_Within_Generic_Unit
10251 -- Returns True if Declared_Entity is declared within the declarative
10252 -- region of Generic_Unit; otherwise returns False.
10254 ---------------------------
10255 -- Accessibility_Message --
10256 ---------------------------
10261 begin
10262 -- In an instance, this is a runtime check, but one we
10263 -- know will fail, so generate an appropriate warning.
10267 Error_Msg_F
10276 else
10279 -- Check for case where we have a missing access definition
10282 and then
10284 N_Index_Or_Discriminant_Constraint)
10285 then
10289 loop
10294 Error_Msg_NE
10303 ----------------------------------
10304 -- Declared_Within_Generic_Unit --
10305 ----------------------------------
10307 function Declared_Within_Generic_Unit
10310 is
10313 begin
10319 -- We have to step to the scope of the generic's entity, because
10320 -- otherwise we'll just get back the same generic.
10322 Generic_Encloser :=
10323 Enclosing_Generic_Unit
10330 -- Start of processing for Resolve_Attribute
10332 begin
10333 -- If error during analysis, no point in continuing, except for array
10334 -- types, where we get better recovery by using unconstrained indexes
10335 -- than nothing at all (see Check_Array_Type).
10342 then
10346 -- If attribute was universal type, reset to actual type
10350 then
10354 -- Remaining processing depends on attribute
10358 ------------
10359 -- Access --
10360 ------------
10362 -- For access attributes, if the prefix denotes an entity, it is
10363 -- interpreted as a name, never as a call. It may be overloaded,
10364 -- in which case resolution uses the profile of the context type.
10365 -- Otherwise prefix must be resolved.
10367 when Attribute_Access
10368 | Attribute_Unchecked_Access
10369 | Attribute_Unrestricted_Access
10370 =>
10371 -- Note possible modification if we have a variable
10374 declare
10379 -- Skip this for the case of Unrestricted_Access occuring in
10380 -- the context of a Valid check, since this otherwise leads
10381 -- to a missed warning (the Valid check does not really
10382 -- modify!) If this case, Note will be reset to False.
10384 -- Skip it as well if the type is an Acccess_To_Constant,
10385 -- given that no use of the value can modify the prefix.
10387 begin
10390 then
10397 then
10411 -- The following comes from a query concerning improper use of
10412 -- universal_access in equality tests involving anonymous access
10413 -- types. Another good reason for 'Ref, but for now disable the
10414 -- test, which breaks several filed tests???
10419 then
10424 -- Case where prefix is an entity name
10428 -- Deal with case where prefix itself is overloaded
10436 -- The prefix is definitely NOT overloaded anymore at
10437 -- this point, so we reset the Is_Overloaded flag to
10438 -- avoid any confusion when reanalyzing the node.
10449 -- If Prefix is a subprogram name, this reference freezes,
10450 -- but not if within spec expression mode. The profile of
10451 -- the subprogram is not frozen at this point.
10457 -- If it is a type, there is nothing to resolve.
10458 -- If it is a subprogram, do not freeze its profile.
10459 -- If it is an object, complete its resolution.
10466 -- Nothing to do if prefix is a type name
10471 -- Otherwise non-overloaded other case, resolve the prefix
10473 else
10477 -- Some further error checks
10486 then
10491 Error_Msg_F
10495 -- An attempt to take 'Access of a function that renames an
10496 -- enumeration literal. Issue a specialized error message.
10501 then
10502 Error_Msg_F
10512 -- Assignments, return statements, components of aggregates,
10513 -- generic instantiations will require convention checks if
10514 -- the type is an access to subprogram. Given that there will
10515 -- also be accessibility checks on those, this is where the
10516 -- checks can eventually be centralized ???
10519 E_Access_Subprogram_Type,
10520 E_Anonymous_Access_Protected_Subprogram_Type,
10521 E_Anonymous_Access_Subprogram_Type)
10522 then
10523 -- Deal with convention mismatch
10527 then
10528 -- The rule in 6.3.1 (8) deserves a special error
10529 -- message.
10534 and then Inside_A_Generic
10535 then
10536 declare
10539 begin
10541 Error_Msg_FE
10545 Error_Msg_N
10550 else
10551 Error_Msg_FE
10559 then
10560 Error_Msg_FE
10565 else
10566 Check_Subtype_Conformant
10574 Error_Msg_F
10580 -- Check the static accessibility rule of 3.10.2(32).
10581 -- This rule also applies within the private part of an
10582 -- instantiation. This rule does not apply to anonymous
10583 -- access-to-subprogram types in access parameters.
10586 and then not In_Instance_Body
10587 and then
10592 then
10593 Error_Msg_F
10596 -- Check the restriction of 3.10.2(32) that disallows the
10597 -- access attribute within a generic body when the ultimate
10598 -- ancestor of the type of the attribute is declared outside
10599 -- of the generic unit and the subprogram is declared within
10600 -- that generic unit. This includes any such attribute that
10601 -- occurs within the body of a generic unit that is a child
10602 -- of the generic unit where the subprogram is declared.
10604 -- The rule also prohibits applying the attribute when the
10605 -- access type is a generic formal access type (since the
10606 -- level of the actual type is not known). This restriction
10607 -- does not apply when the attribute type is an anonymous
10608 -- access-to-subprogram type. Note that this check was
10609 -- revised by AI-229, because the original Ada 95 rule
10610 -- was too lax. The original rule only applied when the
10611 -- subprogram was declared within the body of the generic,
10612 -- which allowed the possibility of dangling references).
10613 -- The rule was also too strict in some cases, in that it
10614 -- didn't permit the access to be declared in the generic
10615 -- spec, whereas the revised rule does (as long as it's not
10616 -- a formal type).
10618 -- There are a couple of subtleties of the test for applying
10619 -- the check that are worth noting. First, we only apply it
10620 -- when the levels of the subprogram and access type are the
10621 -- same (the case where the subprogram is statically deeper
10622 -- was applied above, and the case where the type is deeper
10623 -- is always safe). Second, we want the check to apply
10624 -- within nested generic bodies and generic child unit
10625 -- bodies, but not to apply to an attribute that appears in
10626 -- the generic unit's specification. This is done by testing
10627 -- that the attribute's innermost enclosing generic body is
10628 -- not the same as the innermost generic body enclosing the
10629 -- generic unit where the subprogram is declared (we don't
10630 -- want the check to apply when the access attribute is in
10631 -- the spec and there's some other generic body enclosing
10632 -- generic). Finally, there's no point applying the check
10633 -- when within an instance, because any violations will have
10634 -- been caught by the compilation of the generic unit.
10636 -- We relax this check in Relaxed_RM_Semantics mode for
10637 -- compatibility with legacy code for use by Ada source
10638 -- code analyzers (e.g. CodePeer).
10641 and then not Relaxed_RM_Semantics
10642 and then not In_Instance
10646 Enclosing_Generic_Body
10651 E_Anonymous_Access_Subprogram_Type
10653 E_Anonymous_Access_Protected_Subprogram_Type
10654 then
10655 -- The attribute type's ultimate ancestor must be
10656 -- declared within the same generic unit as the
10657 -- subprogram is declared (including within another
10658 -- nested generic unit). The error message is
10659 -- specialized to say "ancestor" for the case where the
10660 -- access type is not its own ancestor, since saying
10661 -- simply "access type" would be very confusing.
10663 if not Declared_Within_Generic_Unit
10666 then
10667 Error_Msg_N
10669 N);
10672 Error_Msg_NE
10676 else
10677 Error_Msg_NE
10683 Error_Msg_NE
10688 -- If the ultimate ancestor of the attribute's type is
10689 -- a formal type, then the attribute is illegal because
10690 -- the actual type might be declared at a higher level.
10691 -- The error message is specialized to say "ancestor"
10692 -- for the case where the access type is not its own
10693 -- ancestor, since saying simply "access type" would be
10694 -- very confusing.
10698 Error_Msg_N
10700 N);
10701 else
10702 Error_Msg_N
10710 -- If this is a renaming, an inherited operation, or a
10711 -- subprogram instance, use the original entity. This may make
10712 -- the node type-inconsistent, so this transformation can only
10713 -- be done if the node will not be reanalyzed. In particular,
10714 -- if it is within a default expression, the transformation
10715 -- must be delayed until the default subprogram is created for
10716 -- it, when the enclosing subprogram is frozen.
10721 and then Expander_Active
10722 then
10729 then
10730 -- Protected operation. If operation is overloaded, must
10731 -- disambiguate. Prefix that denotes protected object itself
10732 -- is resolved with its own type.
10736 Error_Msg_F
10743 -- Implement check implied by 3.10.2 (18.1/2) : F.all'access is
10744 -- statically illegal if F is an anonymous access to subprogram.
10749 E_Anonymous_Access_Subprogram_Type
10750 then
10756 -- Use the designated type of the context to disambiguate
10757 -- Note that this was not strictly conformant to Ada 95,
10758 -- but was the implementation adopted by most Ada 95 compilers.
10759 -- The use of the context type to resolve an Access attribute
10760 -- reference is now mandated in AI-235 for Ada 2005.
10762 declare
10766 begin
10777 else
10781 -- X'Access is illegal if X denotes a constant and the access type
10782 -- is access-to-variable. Same for 'Unchecked_Access. The rule
10783 -- does not apply to 'Unrestricted_Access. If the reference is a
10784 -- default-initialized aggregate component for a self-referential
10785 -- type the reference is legal.
10790 and then
10794 = E_Anonymous_Access_Protected_Subprogram_Type
10798 then
10801 then
10802 -- Legality of a self-reference through an access
10803 -- attribute has been verified in Analyze_Access_Attribute.
10816 then
10817 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
10818 -- imported entity, and the non-limited view is visible, make
10819 -- use of it. If it is an incomplete subtype, use the base type
10820 -- in any case.
10824 then
10833 or else
10837 then
10838 -- Ada 2005 (AI-230): Check the accessibility of anonymous
10839 -- access types for stand-alone objects, record and array
10840 -- components, and return objects. For a component definition
10841 -- the level is the same of the enclosing composite type.
10846 -- Handle cases where Btyp is the anonymous access
10847 -- type of an Ada 2012 stand-alone object.
10850 N_Object_Declaration)
10851 and then
10854 then
10855 -- In an instance, this is a runtime check, but one we know
10856 -- will fail, so generate an appropriate warning. As usual,
10857 -- this kind of warning is an error in SPARK mode.
10861 Error_Msg_F
10870 else
10871 Error_Msg_F
10877 Error_Msg_F
10879 P);
10882 -- Check static matching rule of 3.10.2(27). Nominal subtype
10883 -- of the prefix must statically match the designated type.
10893 -- If the attribute is in the context of an access
10894 -- parameter, then the prefix is allowed to be of
10895 -- the class-wide type (by AI-127).
10900 then
10901 declare
10904 begin
10914 else
10915 Error_Msg_FE
10918 Error_Msg_FE
10926 or else
10929 then
10930 Error_Msg_FE
10932 Error_Msg_FE
10941 then
10942 Apply_Discriminant_Check
10946 -- Ada 2005 (AI-363): Require static matching when designated
10947 -- type has discriminants and a constrained partial view, since
10948 -- in general objects of such types are mutable, so we can't
10949 -- allow the access value to designate a constrained object
10950 -- (because access values must be assumed to designate mutable
10951 -- objects when designated type does not impose a constraint).
10958 and then
10960 or else
10961 not Object_Type_Has_Constrained_Partial_View
10964 then
10967 else
10968 Error_Msg_F
10974 then
10975 declare
10977 begin
10978 Error_Msg_N
10980 Error_Msg_N
10983 Error_Msg_N
10989 -- Check the static accessibility rule of 3.10.2(28). Note that
10990 -- this check is not performed for the case of an anonymous
10991 -- access type, since the access attribute is always legal
10992 -- in such a context.
10996 and then
10998 then
10999 Accessibility_Message;
11005 E_Anonymous_Access_Protected_Subprogram_Type)
11006 then
11009 then
11012 -- Check accessibility of protected object against that of the
11013 -- access type, but only on user code, because the expander
11014 -- creates access references for handlers. If the context is an
11015 -- anonymous_access_to_protected, there are no accessibility
11016 -- checks either. Omit check entirely for Unrestricted_Access.
11022 then
11023 Accessibility_Message;
11026 -- AI05-0225: If the context is not an access to protected
11027 -- function, the prefix must be a variable, given that it may
11028 -- be used subsequently in a protected call.
11033 then
11034 Error_Msg_N
11043 E_Anonymous_Access_Subprogram_Type)
11045 then
11049 -- The context cannot be a pool-specific type, but this is a
11050 -- legality rule, not a resolution rule, so it must be checked
11051 -- separately, after possibly disambiguation (see AI-245).
11055 then
11059 -- The context may be a constrained access type (however ill-
11060 -- advised such subtypes might be) so in order to generate a
11061 -- constraint check when needed set the type of the attribute
11062 -- reference to the base type of the context.
11066 -- Check for incorrect atomic/volatile reference (RM C.6(12))
11071 then
11072 Error_Msg_F
11078 then
11079 Error_Msg_F
11085 -- Check for aliased view. We allow a nonaliased prefix when in
11086 -- an instance because the prefix may have been a tagged formal
11087 -- object, which is defined to be aliased even when the actual
11088 -- might not be (other instance cases will have been caught in
11089 -- the generic). Similarly, within an inlined body we know that
11090 -- the attribute is legal in the original subprogram, therefore
11091 -- legal in the expansion.
11096 and then
11099 and then not In_Instance
11100 and then not In_Inlined_Body
11102 then
11103 -- Here we have a non-aliased view. This is illegal unless we
11104 -- have the case of Unrestricted_Access, where for now we allow
11105 -- this (we will reject later if expected type is access to an
11106 -- unconstrained array with a thin pointer).
11108 -- No need for an error message on a generated access reference
11109 -- for the controlling argument in a dispatching call: error
11110 -- will be reported when resolving the call.
11115 -- Check for unrestricted access where expected type is a thin
11116 -- pointer to an unconstrained array.
11120 then
11121 declare
11123 begin
11126 then
11127 Error_Msg_N
11129 Error_Msg_N
11137 -- Mark that address of entity is taken in case of
11138 -- 'Unrestricted_Access or in case of a subprogram.
11143 then
11147 -- Deal with possible elaboration check
11150 declare
11158 -- If the access has been taken and the body of the subprogram
11159 -- has not been see yet, indirect calls must be protected with
11160 -- elaboration checks. We have the proper elaboration machinery
11161 -- for subprograms declared in packages, but within a block or
11162 -- a subprogram the body will appear in the same declarative
11163 -- part, and we must insert a check in the eventual body itself
11164 -- using the elaboration flag that we generate now. The check
11165 -- is then inserted when the body is expanded. This processing
11166 -- is not needed for a stand alone expression function because
11167 -- the internally generated spec and body are always inserted
11168 -- as a pair in the same declarative list.
11170 begin
11171 if Expander_Active
11180 N_Expression_Function
11181 then
11182 -- Create elaboration variable for it
11188 -- Insert declaration for flag after subprogram
11189 -- declaration. Note that attribute reference may
11190 -- appear within a nested scope.
11195 Object_Definition =>
11197 Expression =>
11201 -- Taking the 'Access of an expression function freezes its
11202 -- expression (RM 13.14 10.3/3). This does not apply to an
11203 -- expression function that acts as a completion because the
11204 -- generated body is immediately analyzed and the expression
11205 -- is automatically frozen.
11209 then
11210 Subp_Body :=
11213 -- The body has already been analyzed when the expression
11214 -- function acts as a completion.
11219 -- Attribute 'Access may appear within the generated body
11220 -- of the expression function subject to the attribute:
11222 -- function F is (... F'Access ...);
11224 -- If the expression function is on the scope stack, then
11225 -- the body is currently being analyzed. Do not reanalyze
11226 -- it because this will lead to infinite recursion.
11231 -- If reference to the expression function appears in an
11232 -- inner scope, for example as an actual in an instance,
11233 -- this is not a freeze point either.
11238 -- Analyze the body of the expression function to freeze
11239 -- the expression. This takes care of the case where the
11240 -- 'Access is part of dispatch table initialization and
11241 -- the generated body of the expression function has not
11242 -- been analyzed yet.
11244 else
11251 -------------
11252 -- Address --
11253 -------------
11255 -- Deal with resolving the type for Address attribute, overloading
11256 -- is not permitted here, since there is no context to resolve it.
11258 when Attribute_Address
11259 | Attribute_Code_Address
11260 =>
11261 -- To be safe, assume that if the address of a variable is taken,
11262 -- it may be modified via this address, so note modification.
11270 then
11276 Error_Msg_F
11283 then
11286 then
11291 -- If this is the name of a derived subprogram, or that of a
11292 -- generic actual, the address is that of the original entity.
11297 then
11308 -- Arr (X .. Y)'address is identical to Arr (X)'address,
11309 -- even if the array is packed and the slice itself is not
11310 -- addressable. Transform the prefix into an indexed component.
11312 -- Note that the transformation is safe only if we know that
11313 -- the slice is non-null. That is because a null slice can have
11314 -- an out of bounds index value.
11316 -- Right now, gigi blows up if given 'Address on a slice as a
11317 -- result of some incorrect freeze nodes generated by the front
11318 -- end, and this covers up that bug in one case, but the bug is
11319 -- likely still there in the cases not handled by this code ???
11321 -- It's not clear what 'Address *should* return for a null
11322 -- slice with out of bounds indexes, this might be worth an ARG
11323 -- discussion ???
11325 -- One approach would be to do a length check unconditionally,
11326 -- and then do the transformation below unconditionally, but
11327 -- analyze with checks off, avoiding the problem of the out of
11328 -- bounds index. This approach would interpret the address of
11329 -- an out of bounds null slice as being the address where the
11330 -- array element would be if there was one, which is probably
11331 -- as reasonable an interpretation as any ???
11333 declare
11338 begin
11340 and then
11341 Not_Null_Range
11344 then
11345 Lo :=
11352 then
11355 else
11370 ------------------
11371 -- Body_Version --
11372 ------------------
11374 -- Prefix of Body_Version attribute can be a subprogram name which
11375 -- must not be resolved, since this is not a call.
11380 ------------
11381 -- Caller --
11382 ------------
11384 -- Prefix of Caller attribute is an entry name which must not
11385 -- be resolved, since this is definitely not an entry call.
11390 ------------------
11391 -- Code_Address --
11392 ------------------
11394 -- Shares processing with Address attribute
11396 -----------
11397 -- Count --
11398 -----------
11400 -- If the prefix of the Count attribute is an entry name it must not
11401 -- be resolved, since this is definitely not an entry call. However,
11402 -- if it is an element of an entry family, the index itself may
11403 -- have to be resolved because it can be a general expression.
11408 then
11409 declare
11412 begin
11418 ----------------
11419 -- Elaborated --
11420 ----------------
11422 -- Prefix of the Elaborated attribute is a subprogram name which
11423 -- must not be resolved, since this is definitely not a call. Note
11424 -- that it is a library unit, so it cannot be overloaded here.
11429 -------------
11430 -- Enabled --
11431 -------------
11433 -- Prefix of Enabled attribute is a check name, which must be treated
11434 -- specially and not touched by Resolve.
11439 ----------------
11440 -- Loop_Entry --
11441 ----------------
11443 -- Do not resolve the prefix of Loop_Entry, instead wait until the
11444 -- attribute has been expanded (see Expand_Loop_Entry_Attributes).
11445 -- The delay ensures that any generated checks or temporaries are
11446 -- inserted before the relocated prefix.
11451 --------------------
11452 -- Mechanism_Code --
11453 --------------------
11455 -- Prefix of the Mechanism_Code attribute is a function name
11456 -- which must not be resolved. Should we check for overloaded ???
11461 ------------------
11462 -- Partition_ID --
11463 ------------------
11465 -- Most processing is done in sem_dist, after determining the
11466 -- context type. Node is rewritten as a conversion to a runtime call.
11472 ------------------
11473 -- Pool_Address --
11474 ------------------
11479 -----------
11480 -- Range --
11481 -----------
11483 -- We replace the Range attribute node with a range expression whose
11484 -- bounds are the 'First and 'Last attributes applied to the same
11485 -- prefix. The reason that we do this transformation here instead of
11486 -- in the expander is that it simplifies other parts of the semantic
11487 -- analysis which assume that the Range has been replaced; thus it
11488 -- must be done even when in semantic-only mode (note that the RM
11489 -- specifically mentions this equivalence, we take care that the
11490 -- prefix is only evaluated once).
11497 begin
11504 HB :=
11510 LB :=
11516 -- Do not share the dimension indicator, if present. Even though
11517 -- it is a static constant, its source location may be modified
11518 -- when printing expanded code and node sharing will lead to chaos
11519 -- in Sprint.
11525 -- If the original was marked as Must_Not_Freeze (see code in
11526 -- Sem_Ch3.Make_Index), then make sure the rewriting does not
11527 -- freeze either.
11538 -- Preserve Sloc of prefix in the new bounds, so that the
11539 -- posted warning can be removed if we are within unreachable
11540 -- code.
11549 -- Ensure that the expanded range does not have side effects
11554 -- Normally after resolving attribute nodes, Eval_Attribute
11555 -- is called to do any possible static evaluation of the node.
11556 -- However, here since the Range attribute has just been
11557 -- transformed into a range expression it is no longer an
11558 -- attribute node and therefore the call needs to be avoided
11559 -- and is accomplished by simply returning from the procedure.
11564 ------------
11565 -- Result --
11566 ------------
11568 -- We will only come here during the prescan of a spec expression
11569 -- containing a Result attribute. In that case the proper Etype has
11570 -- already been set, and nothing more needs to be done here.
11575 ----------------------
11576 -- Unchecked_Access --
11577 ----------------------
11579 -- Processing is shared with Access
11581 -------------------------
11582 -- Unrestricted_Access --
11583 -------------------------
11585 -- Processing is shared with Access
11587 ------------
11588 -- Update --
11589 ------------
11591 -- Resolve aggregate components in component associations
11600 begin
11601 -- Set the Etype of the aggregate to that of the prefix, even
11602 -- though the aggregate may not be a proper representation of a
11603 -- value of the type (missing or duplicated associations, etc.)
11604 -- Complete resolution of the prefix. Note that in Ada 2012 it
11605 -- can be a qualified expression that is e.g. an aggregate.
11610 -- For an array type, resolve expressions with the component type
11611 -- of the array, and apply constraint checks when needed.
11619 -- For scalar array components set Do_Range_Check when
11620 -- needed. Constraint checking on non-scalar components
11621 -- is done in Aggregate_Constraint_Checks, but only if
11622 -- full analysis is enabled. These flags are not set in
11623 -- the front-end in GnatProve mode.
11628 then
11631 then
11634 else
11639 -- The choices in the association are static constants,
11640 -- or static aggregates each of whose components belongs
11641 -- to the proper index type. However, they must also
11642 -- belong to the index subtype (s) of the prefix, which
11643 -- may be a subtype (e.g. given by a slice).
11645 -- Choices may also be identifiers with no staticness
11646 -- requirements, in which case they must resolve to the
11647 -- index type.
11649 declare
11654 begin
11664 else
11683 -- For a record type, use type of each component, which is
11684 -- recorded during analysis.
11686 else
11694 then
11699 and then not Range_Checks_Suppressed
11701 then
11711 ---------
11712 -- Val --
11713 ---------
11715 -- Apply range check. Note that we did not do this during the
11716 -- analysis phase, since we wanted Eval_Attribute to have a
11717 -- chance at finding an illegal out of range value.
11721 -- Note that we do our own Eval_Attribute call here rather than
11722 -- use the common one, because we need to do processing after
11723 -- the call, as per above comment.
11727 -- Eval_Attribute may replace the node with a raise CE, or
11728 -- fold it to a constant. Obviously we only apply a scalar
11729 -- range check if this did not happen.
11733 then
11739 -------------
11740 -- Version --
11741 -------------
11743 -- Prefix of Version attribute can be a subprogram name which
11744 -- must not be resolved, since this is not a call.
11749 ----------------------
11750 -- Other Attributes --
11751 ----------------------
11753 -- For other attributes, resolve prefix unless it is a type. If
11754 -- the attribute reference itself is a type name ('Base and 'Class)
11755 -- then this is only legal within a task or protected record.
11762 -- If the attribute reference itself is a type name ('Base,
11763 -- 'Class) then this is only legal within a task or protected
11764 -- record. What is this all about ???
11769 then
11771 else
11772 Error_Msg_N
11777 -- For attributes whose argument may be a string, complete
11778 -- resolution of argument now. This avoids premature expansion
11779 -- (and the creation of transient scopes) before the attribute
11780 -- reference is resolved.
11795 -- If the prefix of the attribute is a class-wide type then it
11796 -- will be expanded into a dispatching call to a predefined
11797 -- primitive. Therefore we must check for potential violation
11798 -- of such restriction.
11805 -- Mark use clauses of the original prefix if the attribute is applied
11806 -- to an entity.
11810 then
11814 -- Normally the Freezing is done by Resolve but sometimes the Prefix
11815 -- is not resolved, in which case the freezing must be done now.
11817 -- For an elaboration check on a subprogram, we do not freeze its type.
11818 -- It may be declared in an unrelated scope, in particular in the case
11819 -- of a generic function whose type may remain unelaborated.
11824 else
11828 -- Finally perform static evaluation on the attribute reference
11834 ------------------------
11835 -- Set_Boolean_Result --
11836 ------------------------
11840 begin
11843 else
11848 -------------------------------
11849 -- Statically_Denotes_Object --
11850 -------------------------------
11855 begin
11862 then
11863 declare
11867 begin
11874 else
11882 then
11887 then
11896 else
11901 --------------------------------
11902 -- Stream_Attribute_Available --
11903 --------------------------------
11905 function Stream_Attribute_Available
11909 is
11912 -- Start of processing for Stream_Attribute_Available
11914 begin
11915 -- We need some comments in this body ???
11929 then
11936 then
11940 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
11945 then
11951 then
11955 -- Case of Read and Write: check for attribute definition clause that
11956 -- applies to an ancestor type.
11968 -- In Ada 95 mode, also consider a non-visible definition
11970 declare
11972 begin
11974 and then Stream_Attribute_Available