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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) 1992-2018, 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 ------------------------------------------------------------------------------
87 -- Synonyms to be used when these constants are used as Boolean values
90 -- Exception raised if an error is detected during attribute processing,
91 -- used so that we can abandon the processing so we don't run into
92 -- trouble with cascaded errors.
94 -- The following array is the list of attributes defined in the Ada 83 RM.
95 -- In Ada 83 mode, these are the only recognized attributes. In other Ada
96 -- modes all these attributes are recognized, even if removed in Ada 95.
99 Attribute_Address |
100 Attribute_Aft |
101 Attribute_Alignment |
102 Attribute_Base |
103 Attribute_Callable |
104 Attribute_Constrained |
105 Attribute_Count |
106 Attribute_Delta |
107 Attribute_Digits |
108 Attribute_Emax |
109 Attribute_Epsilon |
110 Attribute_First |
111 Attribute_First_Bit |
112 Attribute_Fore |
113 Attribute_Image |
114 Attribute_Large |
115 Attribute_Last |
116 Attribute_Last_Bit |
117 Attribute_Leading_Part |
118 Attribute_Length |
119 Attribute_Machine_Emax |
120 Attribute_Machine_Emin |
121 Attribute_Machine_Mantissa |
122 Attribute_Machine_Overflows |
123 Attribute_Machine_Radix |
124 Attribute_Machine_Rounds |
125 Attribute_Mantissa |
126 Attribute_Pos |
127 Attribute_Position |
128 Attribute_Pred |
129 Attribute_Range |
130 Attribute_Safe_Emax |
131 Attribute_Safe_Large |
132 Attribute_Safe_Small |
133 Attribute_Size |
134 Attribute_Small |
135 Attribute_Storage_Size |
136 Attribute_Succ |
137 Attribute_Terminated |
138 Attribute_Val |
139 Attribute_Value |
140 Attribute_Width => True,
141 others => False);
143 -- The following array is the list of attributes defined in the Ada 2005
144 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
145 -- but in Ada 95 they are considered to be implementation defined.
148 Attribute_Machine_Rounding |
149 Attribute_Mod |
150 Attribute_Priority |
151 Attribute_Stream_Size |
155 -- The following array is the list of attributes defined in the Ada 2012
156 -- RM which are not defined in Ada 2005. These are recognized in Ada 95
157 -- and Ada 2005 modes, but are considered to be implementation defined.
160 Attribute_First_Valid |
161 Attribute_Has_Same_Storage |
162 Attribute_Last_Valid |
163 Attribute_Max_Alignment_For_Allocation => True,
164 others => False);
166 -- The following array contains all attributes that imply a modification
167 -- of their prefixes or result in an access value. Such prefixes can be
168 -- considered as lvalues.
170 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
172 Attribute_Access |
173 Attribute_Address |
174 Attribute_Input |
175 Attribute_Read |
176 Attribute_Unchecked_Access |
180 -----------------------
181 -- Local_Subprograms --
182 -----------------------
185 -- Performs compile time evaluation of attributes where possible, leaving
186 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
187 -- set, and replacing the node with a literal node if the value can be
188 -- computed at compile time. All static attribute references are folded,
189 -- as well as a number of cases of non-static attributes that can always
190 -- be computed at compile time (e.g. floating-point model attributes that
191 -- are applied to non-static subtypes). Of course in such cases, the
192 -- Is_Static_Expression flag will not be set on the resulting literal.
193 -- Note that the only required action of this procedure is to catch the
194 -- static expression cases as described in the RM. Folding of other cases
195 -- is done where convenient, but some additional non-static folding is in
196 -- Expand_N_Attribute_Reference in cases where this is more convenient.
198 function Is_Anonymous_Tagged_Base
201 -- For derived tagged types that constrain parent discriminants we build
202 -- an anonymous unconstrained base type. We need to recognize the relation
203 -- between the two when analyzing an access attribute for a constrained
204 -- component, before the full declaration for Typ has been analyzed, and
205 -- where therefore the prefix of the attribute does not match the enclosing
206 -- scope.
209 -- Rewrites node N with an occurrence of either Standard_False or
210 -- Standard_True, depending on the value of the parameter B. The
211 -- result is marked as a static expression.
214 -- Predicate used to check the legality of the prefix to 'Loop_Entry and
215 -- 'Old, when the prefix is not an entity name. Current RM specfies that
216 -- the prefix must be a direct or expanded name, but it has been proposed
217 -- that the prefix be allowed to be a selected component that does not
218 -- depend on a discriminant, or an indexed component with static indices.
219 -- Current code for this predicate implements this more permissive
220 -- implementation.
222 -----------------------
223 -- Analyze_Attribute --
224 -----------------------
236 -- Type of prefix after analysis
239 -- Base type of prefix after analysis
241 -----------------------
242 -- Local Subprograms --
243 -----------------------
246 -- Semantic checks for valid use of Address attribute. This was made
247 -- a separate routine with the idea of using it for unrestricted access
248 -- which seems like it should follow the same rules, but that turned
249 -- out to be impractical. So now this is only used for Address.
252 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
253 -- Internally, Id distinguishes which of the three cases is involved.
255 procedure Analyze_Attribute_Old_Result
258 -- Common processing for attributes 'Old and 'Result. The routine checks
259 -- that the attribute appears in a postcondition-like aspect or pragma
260 -- associated with a suitable subprogram or a body. Flag Legal is set
261 -- when the above criteria are met. Spec_Id denotes the entity of the
262 -- subprogram [body] or Empty if the attribute is illegal.
265 -- Common processing for attributes 'Img, 'Image, 'Wide_Image, and
266 -- 'Wide_Wide_Image. The routine checks that the prefix is valid and
267 -- sets the type of the attribute to the one specified by Str_Typ (e.g.
268 -- Standard_String for 'Image and Standard_Wide_String for 'Wide_Image).
271 -- Output error message for use of a predicate (First, Last, Range) not
272 -- allowed with a type that has predicates. If the type is a generic
273 -- actual, then the message is a warning, and we generate code to raise
274 -- program error with an appropriate reason. No error message is given
275 -- for internally generated uses of the attributes. This legality rule
276 -- only applies to scalar types.
279 -- Common procedure used by First, Last, Range attribute to check
280 -- that the prefix is a constrained array or scalar type, or a name
281 -- of an array object, and that an argument appears only if appropriate
282 -- (i.e. only in the array case).
285 -- Common semantic checks for all array attributes. Checks that the
286 -- prefix is a constrained array type or the name of an array object.
287 -- The error message for non-arrays is specialized appropriately.
290 -- Common semantic checks for Asm_Input and Asm_Output attributes
293 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
294 -- Position. Checks prefix is an appropriate selected component.
297 -- Check that prefix of attribute N is a decimal fixed-point type
300 -- If the prefix of attribute is an object of an access type, then
301 -- introduce an explicit dereference, and adjust P_Type accordingly.
304 -- Verify that prefix of attribute N is a discrete type
307 -- Check that no attribute arguments are present
310 -- Check that there are zero or one attribute arguments present
313 -- Check that exactly one attribute argument is present
316 -- Check that two attribute arguments are present
319 -- If the prefix type of 'Image is an enumeration type, set all its
320 -- literals as referenced, since the image function could possibly end
321 -- up referencing any of the literals indirectly. Same for Enum_Val.
322 -- Set the flag only if the reference is in the main code unit. Same
323 -- restriction when resolving 'Value; otherwise an improperly set
324 -- reference when analyzing an inlined body will lose a proper
325 -- warning on a useless with_clause.
328 -- Perform all checks for First_Valid and Last_Valid attributes
331 -- Verify that prefix of attribute N is a fixed type
334 -- Verify that prefix of attribute N is a fixed type and that
335 -- no attribute expressions are present.
338 -- Verify that prefix of attribute N is a float type
341 -- Verify that prefix of attribute N is a float type and that
342 -- no attribute expressions are present.
345 -- Verify that prefix of attribute N is a float type and that
346 -- exactly one attribute expression is present.
349 -- Verify that prefix of attribute N is a float type and that
350 -- two attribute expressions are present
353 -- Issue an error in formal mode because attribute N is allowed
356 -- Verify that prefix of attribute N is an integer type
359 -- Verify that prefix of attribute N is a modular integer type
362 -- Check that P (the prefix of the attribute) is not an CPP type
363 -- for which no Ada predefined primitive is available.
366 -- Check that P (the prefix of the attribute) is not an incomplete
367 -- type or a private type for which no full view has been given.
370 -- Check that P is an object reference
373 -- Validity checking for PolyORB/DSA attribute
376 -- Verify that prefix of attribute N is a program unit
379 -- Verify that prefix of attribute N is fixed or float type
382 -- Verify that prefix of attribute N is a scalar type
385 -- Verify that prefix of attribute N is package Standard. Also checks
386 -- that there are no arguments.
389 -- Validity checking for stream attribute. Nam is the TSS name of the
390 -- corresponding possible defined attribute function (e.g. for the
391 -- Read attribute, Nam will be TSS_Stream_Read).
394 -- Verify that prefix of attribute N is package System
397 -- Verify that prefix of attribute N is a task or task type
400 -- Verify that the prefix of attribute N is a type
403 -- Check that Nod is of the form of a library unit name, i.e that
404 -- it is an identifier, or a selected component whose prefix is
405 -- itself of the form of a library unit name. Note that this is
406 -- quite different from Check_Program_Unit, since it only checks
407 -- the syntactic form of the name, not the semantic identity. This
408 -- is because it is used with attributes (Elab_Body, Elab_Spec and
409 -- Elaborated) which can refer to non-visible unit.
415 -- Posts error using Error_Msg_N at given node, sets type of attribute
416 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
417 -- semantic processing. The message typically contains a % insertion
418 -- character which is replaced by the attribute name. The call with
419 -- no arguments is used when the caller has already generated the
420 -- required error messages.
424 -- Like Error_Attr, but error is posted at the start of the prefix
427 -- Common processing for attributes Definite and Has_Discriminants.
428 -- Checks that prefix is generic indefinite formal type.
431 -- Common processing for attributes Max_Alignment_For_Allocation and
432 -- Max_Size_In_Storage_Elements.
435 -- Common processing for attributes Max and Min
438 -- Used to process attributes whose prefix is package Standard which
439 -- yield values of type Universal_Integer. The attribute reference
440 -- node is rewritten with an integer literal of the given value which
441 -- is marked as static.
444 -- Called when Loop_Entry or Old is used in a potentially unevaluated
445 -- expression. Generates appropriate message or warning depending on
446 -- the setting of Opt.Uneval_Old (or flags in an N_Aspect_Specification
447 -- node in the aspect case).
451 -- Signal unexpected attribute argument (En is the argument), and then
452 -- raises Bad_Attribute to avoid any further semantic processing.
455 -- Called when processing an attribute that is a function call to a
456 -- non-static function, i.e. an attribute function that either takes
457 -- non-scalar arguments or returns a non-scalar result. Verifies that
458 -- such a call does not appear in a preelaborable context.
460 --------------------
461 -- Address_Checks --
462 --------------------
465 begin
466 -- An Address attribute created by expansion is legal even when it
467 -- applies to other entity-denoting expressions.
472 -- Address attribute on a protected object self reference is legal
477 -- Address applied to an entity
480 declare
483 begin
488 -- An Address attribute is accepted when generated by the
489 -- compiler for dispatching operation, and an error is
490 -- issued once the subprogram is frozen (to avoid confusing
491 -- errors about implicit uses of Address in the dispatch
492 -- table initialization).
496 then
497 Error_Attr_P
501 -- It is illegal to apply 'Address to an intrinsic
502 -- subprogram. This is now formalized in AI05-0095.
503 -- In an instance, an attempt to obtain 'Address of an
504 -- intrinsic subprogram (e.g the renaming of a predefined
505 -- operator that is an actual) raises Program_Error.
513 else
515 Error_Msg_N
519 -- Issue an error if prefix denotes an eliminated subprogram
521 else
525 -- Object or label reference
530 -- Deal with No_Implicit_Aliasing restriction
535 else
540 -- If we have an address of an object, and the attribute
541 -- comes from source, then set the object as potentially
542 -- source modified. We do this because the resulting address
543 -- can potentially be used to modify the variable and we
544 -- might not detect this, leading to some junk warnings.
548 -- Allow Address to be applied to task or protected type,
549 -- returning null address (what is that about???)
555 then
559 -- Anything else is illegal
561 else
566 -- Object is OK
571 -- Subprogram called using dot notation
575 then
578 -- What exactly are we allowing here ??? and is this properly
579 -- documented in the sinfo documentation for this node ???
581 elsif Relaxed_RM_Semantics
583 then
586 -- All other non-entity name cases are illegal
588 else
593 ------------------------------
594 -- Analyze_Access_Attribute --
595 ------------------------------
604 -- Build an access-to-object type whose designated type is DT,
605 -- and whose Ekind is appropriate to the attribute type. The
606 -- type that is constructed is returned as the result.
609 -- Build an access to subprogram whose designated type is the type of
610 -- the prefix. If prefix is overloaded, so is the node itself. The
611 -- result is stored in Acc_Type.
614 -- An access reference whose prefix is a type can legally appear
615 -- within an aggregate, where it is obtained by expansion of
616 -- a defaulted aggregate. The enclosing aggregate that contains
617 -- the self-referenced is flagged so that the self-reference can
618 -- be expanded into a reference to the target object (see exp_aggr).
620 ------------------------------
621 -- Build_Access_Object_Type --
622 ------------------------------
626 New_Internal_Entity
628 begin
636 ----------------------------------
637 -- Build_Access_Subprogram_Type --
638 ----------------------------------
645 -- Deal with possible access to local subprogram. If we have such
646 -- an access, we set a flag to kill all tracked values on any call
647 -- because this access value may be passed around, and any called
648 -- code might use it to access a local procedure which clobbers a
649 -- tracked value. If the scope is a loop or block, indicate that
650 -- value tracking is disabled for the enclosing subprogram.
653 -- Distinguish between access to regular/protected subprograms
655 ------------------------
656 -- Check_Local_Access --
657 ------------------------
660 begin
663 Set_Suppress_Value_Tracking_On_Call
668 --------------
669 -- Get_Kind --
670 --------------
673 begin
676 else
681 -- Start of processing for Build_Access_Subprogram_Type
683 begin
684 -- In the case of an access to subprogram, use the name of the
685 -- subprogram itself as the designated type. Type-checking in
686 -- this case compares the signatures of the designated types.
688 -- Note: This fragment of the tree is temporarily malformed
689 -- because the correct tree requires an E_Subprogram_Type entity
690 -- as the designated type. In most cases this designated type is
691 -- later overridden by the semantics with the type imposed by the
692 -- context during the resolution phase. In the specific case of
693 -- the expression Address!(Prim'Unrestricted_Access), used to
694 -- initialize slots of dispatch tables, this work will be done by
695 -- the expander (see Exp_Aggr).
697 -- The reason to temporarily add this kind of node to the tree
698 -- instead of a proper E_Subprogram_Type itype, is the following:
699 -- in case of errors found in the source file we report better
700 -- error messages. For example, instead of generating the
701 -- following error:
703 -- "expected access to subprogram with profile
704 -- defined at line X"
706 -- we currently generate:
708 -- "expected access to function Z defined at line X"
725 else
744 -- Cannot be applied to intrinsic. Looking at the tests above,
745 -- the only way Etype (N) can still be set to Any_Type is if
746 -- Is_Intrinsic_Subprogram was True for some referenced entity.
753 ----------------------
754 -- OK_Self_Reference --
755 ----------------------
760 begin
763 and then
766 loop
771 -- Check the context: the aggregate must be part of the
772 -- initialization of a type or component, or it is the
773 -- resulting expansion in an initialization procedure.
777 else
795 -- No enclosing aggregate, or not a self-reference
800 -- Start of processing for Analyze_Access_Attribute
802 begin
803 Check_SPARK_05_Restriction_On_Attribute;
804 Check_E0;
807 Error_Attr_P
811 -- Preserve relevant elaboration-related attributes of the context
812 -- which are no longer available or very expensive to recompute once
813 -- analysis, resolution, and expansion are over.
815 Mark_Elaboration_Attributes
820 -- Save the scenario for later examination by the ABE Processing
821 -- phase.
825 -- Case of access to subprogram
829 Error_Attr_P
836 -- Issue an error if the prefix denotes an eliminated subprogram
840 -- Check for obsolescent subprogram reference
844 -- Build the appropriate subprogram type
848 -- For P'Access or P'Unrestricted_Access, where P is a nested
849 -- subprogram, we might be passing P to another subprogram (but we
850 -- don't check that here), which might call P. P could modify
851 -- local variables, so we need to kill current values. It is
852 -- important not to do this for library-level subprograms, because
853 -- Kill_Current_Values is very inefficient in the case of library
854 -- level packages with lots of tagged types.
859 -- Do not kill values on nodes initializing dispatch tables
860 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
861 -- is currently generated by the expander only for this
862 -- purpose. Done to keep the quality of warnings currently
863 -- generated by the compiler (otherwise any declaration of
864 -- a tagged type cleans constant indications from its scope).
868 or else
870 and then Is_Dispatching_Operation
872 then
875 else
876 Kill_Current_Values;
879 -- In the static elaboration model, treat the attribute reference
880 -- as a subprogram call for elaboration purposes. Suppress this
881 -- treatment under debug flag. In any case, we are all done.
883 if Legacy_Elaboration_Checks
884 and not Dynamic_Elaboration_Checks
885 and not Debug_Flag_Dot_UU
886 then
892 -- Component is an operation of a protected type
896 then
905 -- Deal with incorrect reference to a type, but note that some
906 -- accesses are allowed: references to the current type instance,
907 -- or in Ada 2005 self-referential pointer in a default-initialized
908 -- aggregate.
913 -- The reference may appear in an aggregate that has been expanded
914 -- into a loop. Locate scope of type definition, if any.
923 -- OK if we are within the scope of a limited type
924 -- let's mark the component as having per object constraint
933 declare
936 begin
939 loop
944 Set_Has_Per_Object_Constraint
950 Error_Msg_F
954 -- If a current instance attribute appears in a component
955 -- constraint it must appear alone; other contexts (spec-
956 -- expressions, within a task body) are not subject to this
957 -- restriction.
959 if not In_Spec_Expression
961 and then not
963 N_Index_Or_Discriminant_Constraint)
964 then
965 Error_Msg_N
970 Error_Msg_N
975 -- OK if we are in initialization procedure for the type
976 -- in question, in which case the reference to the type
977 -- is rewritten as a reference to the current object.
982 then
990 -- OK if a task type, this test needs sharpening up ???
995 -- OK if self-reference in an aggregate in Ada 2005, and
996 -- the reference comes from a copied default expression.
998 -- Note that we check legality of self-reference even if the
999 -- expression comes from source, e.g. when a single component
1000 -- association in an aggregate has a box association.
1003 and then OK_Self_Reference
1004 then
1007 -- OK if reference to current instance of a protected object
1012 -- Otherwise we have an error case
1014 else
1021 -- If we fall through, we have a normal access to object case
1023 -- Unrestricted_Access is (for now) legal wherever an allocator would
1024 -- be legal, so its Etype is set to E_Allocator. The expected type
1025 -- of the other attributes is a general access type, and therefore
1026 -- we label them with E_Access_Attribute_Type.
1032 else
1033 declare
1036 begin
1047 -- Special cases when we can find a prefix that is an entity name
1049 declare
1053 begin
1055 loop
1059 -- If we have an access to an object, and the attribute
1060 -- comes from source, then set the object as potentially
1061 -- source modified. We do this because the resulting access
1062 -- pointer can be used to modify the variable, and we might
1063 -- not detect this, leading to some junk warnings.
1065 -- We only do this for source references, since otherwise
1066 -- we can suppress warnings, e.g. from the unrestricted
1067 -- access generated for validity checks in -gnatVa mode.
1073 -- Mark entity as address taken in the case of
1074 -- 'Unrestricted_Access or subprograms, and kill current
1075 -- values.
1079 then
1087 N_Indexed_Component)
1088 then
1091 else
1098 ----------------------------------
1099 -- Analyze_Attribute_Old_Result --
1100 ----------------------------------
1102 procedure Analyze_Attribute_Old_Result
1105 is
1107 -- Verify that the attribute appears within pragma Check that mimics
1108 -- a postcondition.
1111 -- Verify that the attribute appears within a consequence of aspect
1112 -- or pragma Contract_Cases denoted by Prag.
1115 -- Verify that the attribute appears within the "Ensures" argument of
1116 -- aspect or pragma Test_Case denoted by Prag.
1118 function Is_Within
1121 -- Subsidiary to Check_Placemenet_In_XXX. Determine whether arbitrary
1122 -- node Nod is within enclosing node Encl_Nod.
1126 -- Emit a general error when the attributes does not appear in a
1127 -- postcondition-like aspect or pragma, and then raises Bad_Attribute
1128 -- to avoid any further semantic processing.
1130 ------------------------------
1131 -- Check_Placement_In_Check --
1132 ------------------------------
1138 begin
1139 -- The "Name" argument of pragma Check denotes a postcondition
1142 Name_Post_Class,
1143 Name_Postcondition,
1144 Name_Refined_Post)
1145 then
1148 -- Otherwise the placement of the attribute is illegal
1150 else
1151 Placement_Error;
1155 ---------------------------------------
1156 -- Check_Placement_In_Contract_Cases --
1157 ---------------------------------------
1164 begin
1165 -- Obtain the argument of the aspect or pragma
1169 else
1179 -- Detect whether the attribute appears within the
1180 -- consequence of the current contract case.
1184 then
1192 -- Otherwise aspect or pragma Contract_Cases is either malformed
1193 -- or the attribute does not appear within a consequence.
1195 Error_Attr
1197 P);
1200 ----------------------------------
1201 -- Check_Placement_In_Test_Case --
1202 ----------------------------------
1206 Test_Case_Arg
1211 begin
1212 -- Detect whether the attribute appears within the "Ensures"
1213 -- expression of aspect or pragma Test_Case.
1218 else
1219 Error_Attr
1225 ---------------
1226 -- Is_Within --
1227 ---------------
1229 function Is_Within
1232 is
1235 begin
1241 -- Prevent the search from going too far
1253 ---------------------
1254 -- Placement_Error --
1255 ---------------------
1258 begin
1262 -- Specialize the error message for attribute 'Result
1264 else
1265 Error_Attr
1267 P);
1271 -- Local variables
1277 -- Start of processing for Analyze_Attribute_Old_Result
1279 begin
1280 -- Assume that the attribute is illegal
1285 -- Traverse the parent chain to find the aspect or pragma where the
1286 -- attribute resides.
1293 -- Prevent the search from going too far
1302 -- The attribute is allowed to appear only in postcondition-like
1303 -- aspects or pragmas.
1308 else
1318 -- Attribute 'Result is allowed to appear in aspect or pragma
1319 -- [Refined_]Depends (SPARK RM 6.1.5(11)).
1323 then
1327 Name_Post_Class,
1328 Name_Postcondition,
1329 Name_Refined_Post)
1330 then
1336 else
1337 Placement_Error;
1341 -- Otherwise the placement of the attribute is illegal
1343 else
1344 Placement_Error;
1348 -- Find the related subprogram subject to the aspect or pragma
1352 else
1356 -- The aspect or pragma where the attribute resides should be
1357 -- associated with a subprogram declaration or a body. If this is not
1358 -- the case, then the aspect or pragma is illegal. Return as analysis
1359 -- cannot be carried out. Note that it is legal to have the aspect
1360 -- appear on a subprogram renaming, when the renamed entity is an
1361 -- attribute reference.
1363 -- Generating C code the internally built nested _postcondition
1364 -- subprograms are inlined; after expanded, inlined aspects are
1365 -- located in the internal block generated by the frontend.
1368 and then Modify_Tree_For_C
1369 and then In_Inlined_Body
1370 then
1374 N_Entry_Declaration,
1375 N_Expression_Function,
1376 N_Generic_Subprogram_Declaration,
1377 N_Subprogram_Body,
1378 N_Subprogram_Body_Stub,
1379 N_Subprogram_Declaration,
1380 N_Subprogram_Renaming_Declaration)
1381 then
1385 -- If we get here, then the attribute is legal
1390 -- When generating C code, nested _postcondition subprograms are
1391 -- inlined by the front end to avoid problems (when unnested) with
1392 -- referenced itypes. Handle that here, since as part of inlining the
1393 -- expander nests subprogram within a dummy procedure named _parent
1394 -- (see Build_Postconditions_Procedure and Build_Body_To_Inline).
1395 -- Hence, in this context, the spec_id of _postconditions is the
1396 -- enclosing scope.
1398 if Modify_Tree_For_C
1401 then
1402 -- This situation occurs only when preanalyzing the inlined body
1411 -----------------------------
1412 -- Analyze_Image_Attribute --
1413 -----------------------------
1416 begin
1417 Check_SPARK_05_Restriction_On_Attribute;
1419 -- AI12-00124: The ARG has adopted the GNAT semantics of 'Img for
1420 -- scalar types, so that the prefix can be an object, a named value,
1421 -- or a type, and there is no need for an argument in this case.
1425 then
1426 Check_E0;
1430 Error_Attr_P
1433 else
1434 Check_E1;
1437 -- Check that the prefix type is scalar - much in the same way as
1438 -- Check_Scalar_Type but with custom error messages to denote the
1439 -- variants of 'Image attributes.
1445 then
1453 then
1455 Error_Attr_P
1458 else
1463 Error_Attr_P
1469 Validate_Non_Static_Attribute_Function_Call;
1472 Check_Enum_Image;
1474 -- Check restriction No_Fixed_IO. Note the check of Comes_From_Source
1475 -- to avoid giving a duplicate message for when Image attributes
1476 -- applied to object references get expanded into type-based Image
1477 -- attributes.
1482 then
1487 ---------------------------------
1488 -- Bad_Attribute_For_Predicate --
1489 ---------------------------------
1492 begin
1495 then
1497 Bad_Predicated_Subtype_Use
1502 --------------------------------
1503 -- Check_Array_Or_Scalar_Type --
1504 --------------------------------
1508 -- A current instance of a type in an aspect specification is an
1509 -- object and not a type, and therefore cannot be of a scalar type
1510 -- in the prefix of one of the array attributes if the attribute
1511 -- reference is part of an aspect expression.
1513 -----------------------------
1514 -- In_Aspect_Specification --
1515 -----------------------------
1520 begin
1536 -- Local variables
1541 -- Start of processing for Check_Array_Or_Scalar_Type
1543 begin
1544 -- Case of string literal or string literal subtype. These cases
1545 -- cannot arise from legal Ada code, but the expander is allowed
1546 -- to generate them. They require special handling because string
1547 -- literal subtypes do not have standard bounds (the whole idea
1548 -- of these subtypes is to avoid having to generate the bounds)
1554 -- Scalar types
1557 Check_Type;
1563 Error_Attr
1567 else
1572 -- The following is a special test to allow 'First to apply to
1573 -- private scalar types if the attribute comes from generated
1574 -- code. This occurs in the case of Normalize_Scalars code.
1580 then
1583 -- Array types other than string literal subtypes handled above
1585 else
1586 Check_Array_Type;
1588 -- We know prefix is an array type, or the name of an array
1589 -- object, and that the expression, if present, is static
1590 -- and within the range of the dimensions of the type.
1597 -- First dimension assumed
1601 else
1614 ----------------------
1615 -- Check_Array_Type --
1616 ----------------------
1620 -- Dimension number for array attributes
1622 begin
1623 -- If the type is a string literal type, then this must be generated
1624 -- internally, and no further check is required on its legality.
1629 -- If the type is a composite, it is an illegal aggregate, no point
1630 -- in going on.
1636 -- Normal case of array type or subtype
1638 Check_Either_E0_Or_E1;
1639 Check_Dereference;
1645 then
1646 -- Note: we do not call Error_Attr here, since we prefer to
1647 -- continue, using the relevant index type of the array,
1648 -- even though it is unconstrained. This gives better error
1649 -- recovery behavior.
1652 Error_Msg_F
1656 -- The attribute reference freezes the type, and thus the
1657 -- component type, even if the attribute may not depend on the
1658 -- component. Diagnose arrays with incomplete components now.
1659 -- If the prefix is an access to array, this does not freeze
1660 -- the designated type.
1668 else
1676 then
1680 or else
1681 Attr_Id = Attribute_Last
1682 then
1685 else
1696 then
1697 Flag_Non_Static_Expr
1699 Error_Attr;
1703 then
1710 then
1715 -------------------------
1716 -- Check_Asm_Attribute --
1717 -------------------------
1720 begin
1721 Check_Type;
1722 Check_E2;
1724 -- Check first argument is static string expression
1732 Flag_Non_Static_Expr
1734 Error_Attr;
1737 -- Check second argument is right type
1741 -- Note: that is all we need to do, we don't need to check
1742 -- that it appears in a correct context. The Ada type system
1743 -- will do that for us.
1747 ---------------------
1748 -- Check_Component --
1749 ---------------------
1752 begin
1753 Check_E0;
1756 or else
1758 and then
1760 then
1765 ------------------------------------
1766 -- Check_Decimal_Fixed_Point_Type --
1767 ------------------------------------
1770 begin
1771 Check_Type;
1778 -----------------------
1779 -- Check_Dereference --
1780 -----------------------
1783 begin
1785 -- Case of a subtype mark
1791 -- Case of an expression
1797 -- If there is an implicit dereference, then we must freeze the
1798 -- designated type of the access type, since the type of the
1799 -- referenced array is this type (see AI95-00106).
1801 -- As done elsewhere, freezing must not happen when pre-analyzing
1802 -- a pre- or postcondition or a default value for an object or for
1803 -- a formal parameter.
1824 -------------------------
1825 -- Check_Discrete_Type --
1826 -------------------------
1829 begin
1830 Check_Type;
1837 --------------
1838 -- Check_E0 --
1839 --------------
1842 begin
1848 --------------
1849 -- Check_E1 --
1850 --------------
1853 begin
1854 Check_Either_E0_Or_E1;
1858 -- Special-case attributes that are functions and that appear as
1859 -- the prefix of another attribute. Error is posted on parent.
1863 Name_Code_Address,
1864 Name_Access)
1865 then
1872 else
1878 --------------
1879 -- Check_E2 --
1880 --------------
1883 begin
1891 ---------------------------
1892 -- Check_Either_E0_Or_E1 --
1893 ---------------------------
1896 begin
1902 ----------------------
1903 -- Check_Enum_Image --
1904 ----------------------
1909 begin
1910 -- When an enumeration type appears in an attribute reference, all
1911 -- literals of the type are marked as referenced. This must only be
1912 -- done if the attribute reference appears in the current source.
1913 -- Otherwise the information on references may differ between a
1914 -- normal compilation and one that performs inlining.
1918 then
1927 ----------------------------
1928 -- Check_First_Last_Valid --
1929 ----------------------------
1932 begin
1933 Check_Discrete_Type;
1935 -- Freeze the subtype now, so that the following test for predicates
1936 -- works (we set the predicates stuff up at freeze time)
1940 -- Now test for dynamic predicate
1944 then
1945 Error_Attr_P
1949 -- Check non-static subtype
1955 -- Test case for no values
1960 and then
1962 then
1963 Error_Attr_P
1969 ----------------------------
1970 -- Check_Fixed_Point_Type --
1971 ----------------------------
1974 begin
1975 Check_Type;
1982 ------------------------------
1983 -- Check_Fixed_Point_Type_0 --
1984 ------------------------------
1987 begin
1988 Check_Fixed_Point_Type;
1989 Check_E0;
1992 -------------------------------
1993 -- Check_Floating_Point_Type --
1994 -------------------------------
1997 begin
1998 Check_Type;
2005 ---------------------------------
2006 -- Check_Floating_Point_Type_0 --
2007 ---------------------------------
2010 begin
2011 Check_Floating_Point_Type;
2012 Check_E0;
2015 ---------------------------------
2016 -- Check_Floating_Point_Type_1 --
2017 ---------------------------------
2020 begin
2021 Check_Floating_Point_Type;
2022 Check_E1;
2025 ---------------------------------
2026 -- Check_Floating_Point_Type_2 --
2027 ---------------------------------
2030 begin
2031 Check_Floating_Point_Type;
2032 Check_E2;
2035 ------------------------
2036 -- Check_Integer_Type --
2037 ------------------------
2040 begin
2041 Check_Type;
2048 --------------------------------
2049 -- Check_Modular_Integer_Type --
2050 --------------------------------
2053 begin
2054 Check_Type;
2057 Error_Attr_P
2062 ------------------------
2063 -- Check_Not_CPP_Type --
2064 ------------------------
2067 begin
2071 then
2072 Error_Attr_P
2077 -------------------------------
2078 -- Check_Not_Incomplete_Type --
2079 -------------------------------
2085 begin
2086 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
2087 -- dereference we have to check wrong uses of incomplete types
2088 -- (other wrong uses are checked at their freezing point).
2090 -- In Ada 2012, incomplete types can appear in subprogram
2091 -- profiles, but formals with incomplete types cannot be the
2092 -- prefix of attributes.
2094 -- Example 1: Limited-with
2096 -- limited with Pkg;
2097 -- package P is
2098 -- type Acc is access Pkg.T;
2099 -- X : Acc;
2100 -- S : Integer := X.all'Size; -- ERROR
2101 -- end P;
2103 -- Example 2: Tagged incomplete
2105 -- type T is tagged;
2106 -- type Acc is access all T;
2107 -- X : Acc;
2108 -- S : constant Integer := X.all'Size; -- ERROR
2109 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
2113 then
2122 Error_Attr_P
2125 -- If the prefix is an access type check the designated type
2129 then
2137 -- A legal use of a shadow entity occurs only when the unit where
2138 -- the non-limited view resides is imported via a regular with
2139 -- clause in the current body. Such references to shadow entities
2140 -- may occur in subprogram formals.
2146 then
2150 -- If still incomplete, it can be a local incomplete type, or a
2151 -- limited view whose scope is also a limited view.
2156 then
2157 Error_Attr_P
2160 -- The limited view may be available indirectly through
2161 -- an intermediate unit. If the non-limited view is available
2162 -- the attribute reference is legal.
2165 and then
2168 then
2169 Error_Attr_P
2174 -- Ada 2012 : formals in bodies may be incomplete, but no attribute
2175 -- legally applies.
2180 then
2181 Error_Attr_P
2187 or else In_Spec_Expression
2188 then
2190 else
2195 ----------------------------
2196 -- Check_Object_Reference --
2197 ----------------------------
2202 begin
2203 -- If we need an object, and we have a prefix that is the name of
2204 -- a function entity, convert it into a function call.
2208 then
2217 -- Otherwise we must have an object reference
2224 ----------------------------
2225 -- Check_PolyORB_Attribute --
2226 ----------------------------
2229 begin
2230 Validate_Non_Static_Attribute_Function_Call;
2232 Check_Type;
2233 Check_Not_CPP_Type;
2236 Error_Attr
2241 ------------------------
2242 -- Check_Program_Unit --
2243 ------------------------
2246 begin
2248 declare
2252 begin
2259 and then
2261 or else
2263 then
2272 ---------------------
2273 -- Check_Real_Type --
2274 ---------------------
2277 begin
2278 Check_Type;
2285 -----------------------
2286 -- Check_Scalar_Type --
2287 -----------------------
2290 begin
2291 Check_Type;
2298 ------------------------------------------
2299 -- Check_SPARK_05_Restriction_On_Attribute --
2300 ------------------------------------------
2303 begin
2308 ---------------------------
2309 -- Check_Standard_Prefix --
2310 ---------------------------
2313 begin
2314 Check_E0;
2321 ----------------------------
2322 -- Check_Stream_Attribute --
2323 ----------------------------
2330 -- True when compiling System.Shared_Storage.Shared_Var_Procs body.
2331 -- For this runtime package (always compiled in GNAT mode), we allow
2332 -- stream attributes references for limited types for the case where
2333 -- shared passive objects are implemented using stream attributes,
2334 -- which is the default in GNAT's persistent storage implementation.
2336 begin
2337 Validate_Non_Static_Attribute_Function_Call;
2339 -- With the exception of 'Input, Stream attributes are procedures,
2340 -- and can only appear at the position of procedure calls. We check
2341 -- for this here, before they are rewritten, to give a more precise
2342 -- diagnostic.
2349 N_Aggregate)
2350 then
2353 else
2354 Error_Attr
2358 Check_Type;
2361 -- Stream attributes not allowed on limited types unless the
2362 -- attribute reference was generated by the expander (in which
2363 -- case the underlying type will be used, as described in Sinfo),
2364 -- or the attribute was specified explicitly for the type itself
2365 -- or one of its ancestors (taking visibility rules into account if
2366 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
2367 -- (with no visibility restriction).
2369 declare
2371 begin
2373 In_Shared_Var_Procs :=
2375 else
2384 then
2388 Error_Msg_NE
2391 else
2392 Error_Msg_NE
2397 -- Check for no stream operations allowed from No_Tagged_Streams
2401 then
2403 Error_Msg_NE
2408 -- Check restriction violations
2410 -- First check the No_Streams restriction, which prohibits the use
2411 -- of explicit stream attributes in the source program. We do not
2412 -- prevent the occurrence of stream attributes in generated code,
2413 -- for instance those generated implicitly for dispatching purposes.
2419 -- AI05-0057: if restriction No_Default_Stream_Attributes is active,
2420 -- it is illegal to use a predefined elementary type stream attribute
2421 -- either by itself, or more importantly as part of the attribute
2422 -- subprogram for a composite type. However, if the broader
2423 -- restriction No_Streams is active, stream operations are not
2424 -- generated, and there is no error.
2428 then
2429 declare
2432 begin
2434 or else
2435 Nam = TSS_Stream_Read
2436 then
2437 T :=
2439 else
2440 T :=
2447 Error_Msg_NE
2451 Error_Msg_NE
2458 -- Check special case of Exception_Id and Exception_Occurrence which
2459 -- are not allowed for restriction No_Exception_Registration.
2463 or else
2465 then
2469 -- Here we must check that the first argument is an access type
2470 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
2475 -- Note: the double call to Root_Type here is needed because the
2476 -- root type of a class-wide type is the corresponding type (e.g.
2477 -- X for X'Class, and we really want to go to the root.)
2482 then
2483 Error_Attr
2487 -- Check that the second argument is of the right type if there is
2488 -- one (the Input attribute has only one argument so this is skipped)
2495 then
2496 Error_Attr
2503 Check_Not_CPP_Type;
2506 -------------------------
2507 -- Check_System_Prefix --
2508 -------------------------
2511 begin
2517 -----------------------
2518 -- Check_Task_Prefix --
2519 -----------------------
2522 begin
2525 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
2526 -- task interface class-wide types.
2535 then
2538 else
2540 Error_Attr_P
2544 else
2550 ----------------
2551 -- Check_Type --
2552 ----------------
2554 -- The possibilities are an entity name denoting a type, or an
2555 -- attribute reference that denotes a type (Base or Class). If
2556 -- the type is incomplete, replace it with its full view.
2559 begin
2562 then
2566 Error_Attr_P
2572 then
2578 ---------------------
2579 -- Check_Unit_Name --
2580 ---------------------
2583 begin
2598 ----------------
2599 -- Error_Attr --
2600 ----------------
2603 begin
2610 begin
2613 Error_Attr;
2616 ------------------
2617 -- Error_Attr_P --
2618 ------------------
2621 begin
2624 Error_Attr;
2627 ----------------------------
2628 -- Legal_Formal_Attribute --
2629 ----------------------------
2632 begin
2633 Check_E0;
2637 then
2641 or else In_Instance
2642 or else In_Inlined_Body
2643 then
2648 Error_Attr_P
2652 else
2653 Error_Attr_P
2660 ---------------------------------------------------------------
2661 -- Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements --
2662 ---------------------------------------------------------------
2665 begin
2666 Check_E0;
2667 Check_Type;
2668 Check_Not_Incomplete_Type;
2672 -------------
2673 -- Min_Max --
2674 -------------
2677 begin
2678 Check_E2;
2679 Check_Scalar_Type;
2684 -- Check for comparison on unordered enumeration type
2688 Error_Msg_NE
2694 ------------------------
2695 -- Standard_Attribute --
2696 ------------------------
2699 begin
2700 Check_Standard_Prefix;
2706 --------------------
2707 -- Uneval_Old_Msg --
2708 --------------------
2714 begin
2715 -- If from aspect, then Uneval_Old_Setting comes from flags in the
2716 -- N_Aspect_Specification node that corresponds to the attribute.
2718 -- First find the pragma in which we appear (note that at this stage,
2719 -- even if we appeared originally within an aspect specification, we
2720 -- are now within the corresponding pragma).
2723 loop
2733 else
2737 -- If we did not find the pragma, that's odd, just use the setting
2738 -- from Opt.Uneval_Old. Perhaps this is due to a previous error?
2740 else
2744 -- Processing depends on the setting of Uneval_Old
2748 Error_Attr_P
2754 Error_Msg_F
2766 -------------------------
2767 -- Unexpected Argument --
2768 -------------------------
2771 begin
2775 -------------------------------------------------
2776 -- Validate_Non_Static_Attribute_Function_Call --
2777 -------------------------------------------------
2779 -- This function should be moved to Sem_Dist ???
2782 begin
2783 if In_Preelaborated_Unit
2784 and then not In_Subprogram_Or_Concurrent_Unit
2785 then
2786 Flag_Non_Static_Expr
2791 -- Start of processing for Analyze_Attribute
2793 begin
2794 -- Immediate return if unrecognized attribute (already diagnosed by
2795 -- parser, so there is nothing more that we need to do).
2803 -- Deal with Ada 83 issues
2818 -- Deal with Ada 2005 attributes that are implementation attributes
2819 -- because they appear in a version of Ada before Ada 2005, and
2820 -- similarly for Ada 2012 attributes appearing in an earlier version.
2823 or else
2825 then
2829 -- Remote access to subprogram type access attribute reference needs
2830 -- unanalyzed copy for tree transformation. The analyzed copy is used
2831 -- for its semantic information (whether prefix is a remote subprogram
2832 -- name), the unanalyzed copy is used to construct new subtree rooted
2833 -- with N_Aggregate which represents a fat pointer aggregate.
2839 -- Analyze prefix and exit if error in analysis. If the prefix is an
2840 -- incomplete type, use full view if available. Note that there are
2841 -- some attributes for which we do not analyze the prefix, since the
2842 -- prefix is not a normal name, or else needs special handling.
2848 Aname /= Name_Old
2849 then
2856 then
2864 then
2865 -- Use of current instance within the type. Verify that if the
2866 -- attribute appears within a constraint, it yields an access
2867 -- type, other uses are illegal.
2869 declare
2872 begin
2876 loop
2882 then
2886 then
2887 Error_Msg_N
2903 -- Analyze expressions that may be present, exiting if an error occurs
2909 else
2912 -- Skip analysis for case of Restriction_Set, we do not expect
2913 -- the argument to be analyzed in this case.
2918 -- Check for missing/bad expression (result of previous error)
2940 -- Cases where prefix must be resolvable by itself
2948 then
2949 -- The prefix must be resolvable by itself, without reference to the
2950 -- attribute. One case that requires special handling is a prefix
2951 -- that is a function name, where one interpretation may be a
2952 -- parameterless call. Entry attributes are handled specially below.
2956 then
2962 -- Ada 2005 (AI-345): Since protected and task types have
2963 -- primitive entry wrappers, the attributes Count, and Caller
2964 -- require a context check
2967 declare
2972 begin
2977 else
2986 else
2991 else
2997 -- In SPARK, attributes of private types are only allowed if the full
2998 -- type declaration is visible.
3000 -- Note: the check for Present (Entity (P)) defends against some error
3001 -- conditions where the Entity field is not set.
3007 and then not In_Spec_Expression
3008 then
3012 -- Remaining processing depends on attribute
3016 -- Attributes related to Ada 2012 iterators. Attribute specifications
3017 -- exist for these, but they cannot be queried.
3019 when Attribute_Constant_Indexing
3020 | Attribute_Default_Iterator
3021 | Attribute_Implicit_Dereference
3022 | Attribute_Iterator_Element
3023 | Attribute_Iterable
3024 | Attribute_Variable_Indexing
3025 =>
3028 -- Internal attributes used to deal with Ada 2012 delayed aspects. These
3029 -- were already rejected by the parser. Thus they shouldn't appear here.
3034 ------------------
3035 -- Abort_Signal --
3036 ------------------
3039 Check_Standard_Prefix;
3043 ------------
3044 -- Access --
3045 ------------
3048 Analyze_Access_Attribute;
3049 Check_Not_Incomplete_Type;
3051 -------------
3052 -- Address --
3053 -------------
3056 Check_E0;
3057 Address_Checks;
3058 Check_Not_Incomplete_Type;
3061 ------------------
3062 -- Address_Size --
3063 ------------------
3068 --------------
3069 -- Adjacent --
3070 --------------
3073 Check_Floating_Point_Type_2;
3078 ---------
3079 -- Aft --
3080 ---------
3083 Check_Fixed_Point_Type_0;
3086 ---------------
3087 -- Alignment --
3088 ---------------
3092 -- Don't we need more checking here, cf Size ???
3094 Check_E0;
3095 Check_Not_Incomplete_Type;
3096 Check_Not_CPP_Type;
3099 ---------------
3100 -- Asm_Input --
3101 ---------------
3104 Check_Asm_Attribute;
3106 -- The back end may need to take the address of E2
3114 ----------------
3115 -- Asm_Output --
3116 ----------------
3119 Check_Asm_Attribute;
3126 Error_Attr
3133 -- The back end may need to take the address of E2
3141 -----------------------------
3142 -- Atomic_Always_Lock_Free --
3143 -----------------------------
3146 Check_E0;
3147 Check_Type;
3150 ----------
3151 -- Base --
3152 ----------
3154 -- Note: when the base attribute appears in the context of a subtype
3155 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
3156 -- the following circuit.
3161 begin
3162 Check_E0;
3169 then
3174 and then Warn_On_Redundant_Constructs
3175 then
3176 Error_Msg_NE -- CODEFIX
3182 Check_SPARK_05_Restriction
3192 ---------
3193 -- Bit --
3194 ---------
3197 Check_E0;
3202 -- What about the access object cases ???
3204 else
3210 ---------------
3211 -- Bit_Order --
3212 ---------------
3215 Check_E0;
3216 Check_Type;
3225 else
3233 -- Reset incorrect indication of staticness
3237 ------------------
3238 -- Bit_Position --
3239 ------------------
3241 -- Note: in generated code, we can have a Bit_Position attribute
3242 -- applied to a (naked) record component (i.e. the prefix is an
3243 -- identifier that references an E_Component or E_Discriminant
3244 -- entity directly, and this is interpreted as expected by Gigi.
3245 -- The following code will not tolerate such usage, but when the
3246 -- expander creates this special case, it marks it as analyzed
3247 -- immediately and sets an appropriate type.
3251 Check_Component;
3256 ------------------
3257 -- Body_Version --
3258 ------------------
3261 Check_E0;
3262 Check_Program_Unit;
3265 --------------
3266 -- Callable --
3267 --------------
3270 Check_E0;
3272 Check_Task_Prefix;
3274 ------------
3275 -- Caller --
3276 ------------
3282 begin
3283 Check_E0;
3292 else
3310 -------------
3311 -- Ceiling --
3312 -------------
3315 Check_Floating_Point_Type_1;
3319 -----------
3320 -- Class --
3321 -----------
3325 Check_E0;
3328 -- Applying Class to untagged incomplete type is obsolescent in Ada
3329 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
3330 -- this flag gets set by Find_Type in this situation.
3335 then
3336 declare
3338 begin
3341 then
3347 ------------------
3348 -- Code_Address --
3349 ------------------
3352 Check_E0;
3356 then
3361 and then
3363 then
3367 -- Issue an error if the prefix denotes an eliminated subprogram
3369 else
3375 ----------------------
3376 -- Compiler_Version --
3377 ----------------------
3380 Check_E0;
3381 Check_Standard_Prefix;
3386 --------------------
3387 -- Component_Size --
3388 --------------------
3391 Check_E0;
3394 -- Note: unlike other array attributes, unconstrained arrays are OK
3398 else
3399 Check_Array_Type;
3402 -------------
3403 -- Compose --
3404 -------------
3407 Check_Floating_Point_Type_2;
3412 -----------------
3413 -- Constrained --
3414 -----------------
3417 Check_E0;
3420 -- Case from RM J.4(2) of constrained applied to private type
3426 Error_Msg_N
3431 -- If we are within an instance, the attribute must be legal
3432 -- because it was valid in the generic unit. Ditto if this is
3433 -- an inlining of a function declared in an instance.
3438 -- For sure OK if we have a real private type itself, but must
3439 -- be completed, cannot apply Constrained to incomplete type.
3443 -- Note: this is one of the Annex J features that does not
3444 -- generate a warning from -gnatwj, since in fact it seems
3445 -- very useful, and is used in the GNAT runtime.
3447 Check_Not_Incomplete_Type;
3451 -- Normal (non-obsolescent case) of application to object of
3452 -- a discriminated type.
3454 else
3457 -- If N does not come from source, then we allow the
3458 -- the attribute prefix to be of a private type whose
3459 -- full type has discriminants. This occurs in cases
3460 -- involving expanded calls to stream attributes.
3466 -- Must have discriminants or be an access type designating a type
3467 -- with discriminants. If it is a class-wide type it has unknown
3468 -- discriminants.
3472 or else
3475 then
3478 -- The rule given in 3.7.2 is part of static semantics, but the
3479 -- intent is clearly that it be treated as a legality rule, and
3480 -- rechecked in the visible part of an instance. Nevertheless
3481 -- the intent also seems to be it should legally apply to the
3482 -- actual of a formal with unknown discriminants, regardless of
3483 -- whether the actual has discriminants, in which case the value
3484 -- of the attribute is determined using the J.4 rules. This choice
3485 -- seems the most useful, and is compatible with existing tests.
3490 -- Also allow an object of a generic type if extensions allowed
3491 -- and allow this for any type at all. (this may be obsolete ???)
3495 and then Extensions_Allowed
3496 then
3501 -- Fall through if bad prefix
3503 Error_Attr_P
3506 ---------------
3507 -- Copy_Sign --
3508 ---------------
3511 Check_Floating_Point_Type_2;
3516 -----------
3517 -- Count --
3518 -----------
3525 begin
3526 Check_E0;
3539 then
3543 E_Entry_Family
3544 then
3545 Error_Attr
3548 else
3553 else
3560 then
3561 Error_Attr
3564 else
3576 -- The prefix denotes either the task type, or else a
3577 -- single task whose task type is being analyzed.
3583 then
3585 else
3586 Error_Attr
3595 E_Entry,
3596 E_Entry_Family,
3597 E_Loop)
3598 then
3603 then
3609 declare
3613 begin
3619 -- Ada 2005 (AI-345): Do not consider primitive entry
3620 -- wrappers generated for task or protected types.
3624 then
3627 else
3639 -----------------------
3640 -- Default_Bit_Order --
3641 -----------------------
3646 begin
3647 Check_Standard_Prefix;
3651 else
3663 ----------------------------------
3664 -- Default_Scalar_Storage_Order --
3665 ----------------------------------
3670 begin
3671 Check_Standard_Prefix;
3677 else
3694 --------------
3695 -- Definite --
3696 --------------
3699 Legal_Formal_Attribute;
3701 -----------
3702 -- Delta --
3703 -----------
3706 Check_Fixed_Point_Type_0;
3709 ------------
3710 -- Denorm --
3711 ------------
3714 Check_Floating_Point_Type_0;
3717 -----------
3718 -- Deref --
3719 -----------
3722 Check_Type;
3723 Check_E1;
3727 ---------------------
3728 -- Descriptor_Size --
3729 ---------------------
3732 Check_E0;
3740 ------------
3741 -- Digits --
3742 ------------
3745 Check_E0;
3746 Check_Type;
3750 then
3751 Error_Attr_P
3757 ---------------
3758 -- Elab_Body --
3759 ---------------
3761 -- Also handles processing for Elab_Spec and Elab_Subp_Body
3763 when Attribute_Elab_Body
3764 | Attribute_Elab_Spec
3765 | Attribute_Elab_Subp_Body
3766 =>
3767 Check_E0;
3771 -- We have to manually call the expander in this case to get
3772 -- the necessary expansion (normally attributes that return
3773 -- entities are not expanded).
3777 ---------------
3778 -- Elab_Spec --
3779 ---------------
3781 -- Shares processing with Elab_Body
3783 ----------------
3784 -- Elaborated --
3785 ----------------
3788 Check_E0;
3792 ----------
3793 -- Emax --
3794 ----------
3797 Check_Floating_Point_Type_0;
3800 -------------
3801 -- Enabled --
3802 -------------
3805 Check_Either_E0_Or_E1;
3822 --------------
3823 -- Enum_Rep --
3824 --------------
3828 -- T'Enum_Rep (X) case
3831 Check_E1;
3832 Check_Discrete_Type;
3835 -- X'Enum_Rep case. X must be an object or enumeration literal, and
3836 -- it must be of a discrete type.
3838 elsif not
3840 or else
3844 then
3850 --------------
3851 -- Enum_Val --
3852 --------------
3855 Check_E1;
3856 Check_Type;
3862 -- If the enumeration type has a standard representation, the effect
3863 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3873 -- Non-standard representation case (enumeration with holes)
3875 else
3876 Check_Enum_Image;
3881 -------------
3882 -- Epsilon --
3883 -------------
3886 Check_Floating_Point_Type_0;
3889 --------------
3890 -- Exponent --
3891 --------------
3894 Check_Floating_Point_Type_1;
3898 ------------------
3899 -- External_Tag --
3900 ------------------
3903 Check_E0;
3904 Check_Type;
3912 ---------------
3913 -- Fast_Math --
3914 ---------------
3917 Check_Standard_Prefix;
3920 -----------------------
3921 -- Finalization_Size --
3922 -----------------------
3925 Check_E0;
3927 -- The prefix denotes an object
3932 -- The prefix denotes a type
3935 Check_Type;
3936 Check_Not_Incomplete_Type;
3938 -- Attribute 'Finalization_Size is not defined for class-wide
3939 -- types because it is not possible to know statically whether
3940 -- a definite type will have controlled components or not.
3943 Error_Attr_P
3947 -- The prefix denotes an illegal construct
3949 else
3950 Error_Attr_P
3956 -----------
3957 -- First --
3958 -----------
3961 Check_Array_Or_Scalar_Type;
3962 Bad_Attribute_For_Predicate;
3964 ---------------
3965 -- First_Bit --
3966 ---------------
3969 Check_Component;
3972 -----------------
3973 -- First_Valid --
3974 -----------------
3977 Check_First_Last_Valid;
3980 -----------------
3981 -- Fixed_Value --
3982 -----------------
3985 Check_E1;
3986 Check_Fixed_Point_Type;
3990 -----------
3991 -- Floor --
3992 -----------
3995 Check_Floating_Point_Type_1;
3999 ----------
4000 -- Fore --
4001 ----------
4004 Check_Fixed_Point_Type_0;
4007 --------------
4008 -- Fraction --
4009 --------------
4012 Check_Floating_Point_Type_1;
4016 --------------
4017 -- From_Any --
4018 --------------
4021 Check_E1;
4022 Check_PolyORB_Attribute;
4025 -----------------------
4026 -- Has_Access_Values --
4027 -----------------------
4030 Check_Type;
4031 Check_E0;
4034 ----------------------
4035 -- Has_Same_Storage --
4036 ----------------------
4039 Check_E1;
4041 -- The arguments must be objects of any type
4049 -----------------------
4050 -- Has_Tagged_Values --
4051 -----------------------
4054 Check_Type;
4055 Check_E0;
4058 -----------------------
4059 -- Has_Discriminants --
4060 -----------------------
4063 Legal_Formal_Attribute;
4065 --------------
4066 -- Identity --
4067 --------------
4070 Check_E0;
4076 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to task
4077 -- interface class-wide types.
4086 then
4090 else
4092 Error_Attr_P
4095 else
4096 Error_Attr_P
4101 -----------
4102 -- Image --
4103 -----------
4109 Error_Msg_N
4116 ---------
4117 -- Img --
4118 ---------
4123 -----------
4124 -- Input --
4125 -----------
4128 Check_E1;
4132 -------------------
4133 -- Integer_Value --
4134 -------------------
4137 Check_E1;
4138 Check_Integer_Type;
4141 -- Signal an error if argument type is not a specific fixed-point
4142 -- subtype. An error has been signalled already if the argument
4143 -- was not of a fixed-point type.
4151 -------------------
4152 -- Invalid_Value --
4153 -------------------
4156 Check_E0;
4157 Check_Scalar_Type;
4161 -----------
4162 -- Large --
4163 -----------
4166 Check_E0;
4167 Check_Real_Type;
4170 ----------
4171 -- Last --
4172 ----------
4175 Check_Array_Or_Scalar_Type;
4176 Bad_Attribute_For_Predicate;
4178 --------------
4179 -- Last_Bit --
4180 --------------
4183 Check_Component;
4186 ----------------
4187 -- Last_Valid --
4188 ----------------
4191 Check_First_Last_Valid;
4194 ------------------
4195 -- Leading_Part --
4196 ------------------
4199 Check_Floating_Point_Type_2;
4204 ------------
4205 -- Length --
4206 ------------
4209 Check_Array_Type;
4212 -------------------
4213 -- Library_Level --
4214 -------------------
4217 Check_E0;
4230 ---------------
4231 -- Lock_Free --
4232 ---------------
4235 Check_E0;
4239 Error_Attr_P
4243 ----------------
4244 -- Loop_Entry --
4245 ----------------
4249 -- Inspect the prefix for any uses of entities declared within the
4250 -- related loop. Loop_Id denotes the loop identifier.
4252 --------------------------------
4253 -- Check_References_In_Prefix --
4254 --------------------------------
4260 -- Determine whether a reference mentions an entity declared
4261 -- within the related loop.
4264 -- Determine whether Nod appears in the subtree of Loop_Decl
4266 ---------------------
4267 -- Check_Reference --
4268 ---------------------
4271 begin
4275 then
4276 Error_Attr
4278 Nod);
4280 else
4287 ---------------------
4288 -- Declared_Within --
4289 ---------------------
4294 begin
4300 -- Prevent the search from going too far
4312 -- Start of processing for Check_Prefix_For_Local_References
4314 begin
4318 -- Local variables
4328 -- Start of processing for Loop_Entry
4330 begin
4333 -- Set the type of the attribute now to ensure the successful
4334 -- continuation of analysis even if the attribute is misplaced.
4338 -- Attribute 'Loop_Entry may appear in several flavors:
4340 -- * Prefix'Loop_Entry - in this form, the attribute applies to the
4341 -- nearest enclosing loop.
4343 -- * Prefix'Loop_Entry (Expr) - depending on what Expr denotes, the
4344 -- attribute may be related to a loop denoted by label Expr or
4345 -- the prefix may denote an array object and Expr may act as an
4346 -- indexed component.
4348 -- * Prefix'Loop_Entry (Expr1, ..., ExprN) - the attribute applies
4349 -- to the nearest enclosing loop, all expressions are part of
4350 -- an indexed component.
4352 -- * Prefix'Loop_Entry (Expr) (...) (...) - depending on what Expr
4353 -- denotes, the attribute may be related to a loop denoted by
4354 -- label Expr or the prefix may denote a multidimensional array
4355 -- array object and Expr along with the rest of the expressions
4356 -- may act as indexed components.
4358 -- Regardless of variations, the attribute reference does not have an
4359 -- expression list. Instead, all available expressions are stored as
4360 -- indexed components.
4362 -- When the attribute is part of an indexed component, find the first
4363 -- expression as it will determine the semantics of 'Loop_Entry.
4365 -- If the attribute is itself an index in an indexed component, i.e.
4366 -- a member of a list, the context itself is not relevant (the code
4367 -- below would lead to an infinite loop) and the attribute applies
4368 -- to the enclosing loop.
4372 then
4376 -- The attribute reference appears in the following form:
4378 -- Prefix'Loop_Entry (Exp1, Expr2, ..., ExprN) [(...)]
4380 -- In this case, the loop name is omitted and no rewriting is
4381 -- required.
4386 -- The form of the attribute is:
4388 -- Prefix'Loop_Entry (Expr) [(...)]
4390 -- If Expr denotes a loop entry, the whole attribute and indexed
4391 -- component will have to be rewritten to reflect this relation.
4393 else
4396 -- Do not expand the expression as it may have side effects.
4397 -- Simply preanalyze to determine whether it is a loop name or
4398 -- something else.
4405 then
4408 -- Transform the attribute and enclosing indexed component
4419 -- The prefix must denote an object
4425 -- The prefix cannot be of a limited type because the expansion of
4426 -- Loop_Entry must create a constant initialized by the evaluated
4427 -- prefix.
4433 -- Climb the parent chain to verify the location of the attribute and
4434 -- find the enclosing loop.
4439 -- Locate the corresponding enclosing pragma. Note that in the
4440 -- case of Assert[And_Cut] and Assume, we have already checked
4441 -- that the pragma appears in an appropriate loop location.
4445 Name_Loop_Invariant,
4446 Name_Loop_Variant,
4447 Name_Assert,
4448 Name_Assert_And_Cut,
4449 Name_Assume)
4450 then
4453 -- Locate the enclosing loop (if any). Note that Ada 2012 array
4454 -- iteration may be expanded into several nested loops, we are
4455 -- interested in the outermost one which has the loop identifier,
4456 -- and comes from source.
4462 then
4465 -- The original attribute reference may lack a loop name. Use
4466 -- the name of the enclosing loop because it is the related
4467 -- loop.
4475 -- Prevent the search from going too far
4484 -- Loop_Entry must appear within a Loop_Assertion pragma (Assert,
4485 -- Assert_And_Cut, Assume count as loop assertion pragmas for this
4486 -- purpose if they appear in an appropriate location in a loop,
4487 -- which was already checked by the top level pragma circuit).
4489 -- Loop_Entry also denotes a value and as such can appear within an
4490 -- expression that is an argument for another loop aspect. In that
4491 -- case it will have been expanded into the corresponding assignment.
4493 if Expander_Active
4496 then
4503 -- A Loop_Entry that applies to a given loop statement must not
4504 -- appear within a body of accept statement, if this construct is
4505 -- itself enclosed by the given loop statement.
4514 else
4515 Error_Attr
4521 -- The prefix cannot mention entities declared within the related
4522 -- loop because they will not be visible once the prefix is moved
4523 -- outside the loop.
4527 -- The prefix must denote a static entity if the pragma does not
4528 -- apply to the innermost enclosing loop statement, or if it appears
4529 -- within a potentially unevaluated epxression.
4534 then
4539 then
4540 Error_Attr_P
4545 Uneval_Old_Msg;
4548 -- Replace the Loop_Entry attribute reference by its prefix if the
4549 -- related pragma is ignored. This transformation is OK with respect
4550 -- to typing because Loop_Entry's type is that of its prefix. This
4551 -- early transformation also avoids the generation of a useless loop
4552 -- entry constant.
4558 else
4563 -------------
4564 -- Machine --
4565 -------------
4568 Check_Floating_Point_Type_1;
4572 ------------------
4573 -- Machine_Emax --
4574 ------------------
4577 Check_Floating_Point_Type_0;
4580 ------------------
4581 -- Machine_Emin --
4582 ------------------
4585 Check_Floating_Point_Type_0;
4588 ----------------------
4589 -- Machine_Mantissa --
4590 ----------------------
4593 Check_Floating_Point_Type_0;
4596 -----------------------
4597 -- Machine_Overflows --
4598 -----------------------
4601 Check_Real_Type;
4602 Check_E0;
4605 -------------------
4606 -- Machine_Radix --
4607 -------------------
4610 Check_Real_Type;
4611 Check_E0;
4614 ----------------------
4615 -- Machine_Rounding --
4616 ----------------------
4619 Check_Floating_Point_Type_1;
4623 --------------------
4624 -- Machine_Rounds --
4625 --------------------
4628 Check_Real_Type;
4629 Check_E0;
4632 ------------------
4633 -- Machine_Size --
4634 ------------------
4637 Check_E0;
4638 Check_Type;
4639 Check_Not_Incomplete_Type;
4642 --------------
4643 -- Mantissa --
4644 --------------
4647 Check_E0;
4648 Check_Real_Type;
4651 ---------
4652 -- Max --
4653 ---------
4656 Min_Max;
4658 ----------------------------------
4659 -- Max_Alignment_For_Allocation --
4660 ----------------------------------
4663 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4665 ----------------------------------
4666 -- Max_Size_In_Storage_Elements --
4667 ----------------------------------
4670 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4672 -----------------------
4673 -- Maximum_Alignment --
4674 -----------------------
4679 --------------------
4680 -- Mechanism_Code --
4681 --------------------
4686 then
4690 Check_Either_E0_Or_E1;
4697 Flag_Non_Static_Expr
4699 Error_Attr;
4703 then
4710 ---------
4711 -- Min --
4712 ---------
4715 Min_Max;
4717 ---------
4718 -- Mod --
4719 ---------
4723 -- Note: this attribute is only allowed in Ada 2005 mode, but
4724 -- we do not need to test that here, since Mod is only recognized
4725 -- as an attribute name in Ada 2005 mode during the parse.
4727 Check_E1;
4728 Check_Modular_Integer_Type;
4732 -----------
4733 -- Model --
4734 -----------
4737 Check_Floating_Point_Type_1;
4741 ----------------
4742 -- Model_Emin --
4743 ----------------
4746 Check_Floating_Point_Type_0;
4749 -------------------
4750 -- Model_Epsilon --
4751 -------------------
4754 Check_Floating_Point_Type_0;
4757 --------------------
4758 -- Model_Mantissa --
4759 --------------------
4762 Check_Floating_Point_Type_0;
4765 -----------------
4766 -- Model_Small --
4767 -----------------
4770 Check_Floating_Point_Type_0;
4773 -------------
4774 -- Modulus --
4775 -------------
4778 Check_E0;
4779 Check_Modular_Integer_Type;
4782 --------------------
4783 -- Null_Parameter --
4784 --------------------
4791 -- Used if bad Null parameter attribute node is found. Issues
4792 -- given error message, and also sets the type to Any_Type to
4793 -- avoid blowups later on from dealing with a junk node.
4796 -- Called to check that Proc_Ent is imported subprogram
4798 ------------------------
4799 -- Bad_Null_Parameter --
4800 ------------------------
4803 begin
4808 ----------------------
4809 -- Must_Be_Imported --
4810 ----------------------
4815 begin
4816 -- Ignore check if procedure not frozen yet (we will get
4817 -- another chance when the default parameter is reanalyzed)
4823 Bad_Null_Parameter
4826 else
4831 -- Start of processing for Null_Parameter
4833 begin
4834 Check_Type;
4835 Check_E0;
4838 -- Case of attribute used as default expression
4843 -- Case of attribute used as actual for subprogram (positional)
4847 then
4850 -- Case of attribute used as actual for subprogram (named)
4855 then
4858 -- Not an allowed case
4860 else
4861 Bad_Null_Parameter
4866 -----------------
4867 -- Object_Size --
4868 -----------------
4871 Check_E0;
4872 Check_Type;
4873 Check_Not_Incomplete_Type;
4876 ---------
4877 -- Old --
4878 ---------
4882 -- Inspect the contents of the prefix and detect illegal uses of a
4883 -- nested 'Old, attribute 'Result or a use of an entity declared in
4884 -- the related postcondition expression. Subp_Id is the subprogram to
4885 -- which the related postcondition applies.
4887 --------------------------------
4888 -- Check_References_In_Prefix --
4889 --------------------------------
4893 -- Detect attribute 'Old, attribute 'Result of a use of an entity
4894 -- and perform the appropriate semantic check.
4896 ---------------------
4897 -- Check_Reference --
4898 ---------------------
4901 begin
4902 -- Attributes 'Old and 'Result cannot appear in the prefix of
4903 -- another attribute 'Old.
4907 Name_Result)
4908 then
4911 Error_Msg_N
4913 Nod);
4916 -- Entities mentioned within the prefix of attribute 'Old must
4917 -- be global to the related postcondition. If this is not the
4918 -- case, then the scope of the local entity is nested within
4919 -- that of the subprogram.
4924 then
4925 Error_Attr
4927 Nod);
4930 -- Otherwise keep inspecting the prefix
4932 else
4939 -- Start of processing for Check_References_In_Prefix
4941 begin
4945 -- Local variables
4952 -- Start of processing for Old
4954 begin
4955 -- The attribute reference is a primary. If any expressions follow,
4956 -- then the attribute reference is an indexable object. Transform the
4957 -- attribute into an indexed component and analyze it.
4962 Prefix =>
4973 -- The aspect or pragma where attribute 'Old resides should be
4974 -- associated with a subprogram declaration or a body. If this is not
4975 -- the case, then the aspect or pragma is illegal. Return as analysis
4976 -- cannot be carried out.
4978 -- The exception to this rule is when generating C since in this case
4979 -- postconditions are inlined.
4982 and then Modify_Tree_For_C
4983 and then In_Inlined_Body
4984 then
4991 -- The prefix must be preanalyzed as the full analysis will take
4992 -- place during expansion.
4996 -- Ensure that the prefix does not contain attributes 'Old or 'Result
5000 -- Set the type of the attribute now to prevent cascaded errors
5005 -- Legality checks
5011 -- The prefix is a simple name
5016 -- Emit a warning when the prefix is a constant. Note that the use
5017 -- of Error_Attr would reset the type of N to Any_Type even though
5018 -- this is a warning. Use Error_Msg_XXX instead.
5022 Error_Msg_N
5026 -- Otherwise the prefix is not a simple name
5028 else
5029 -- Ensure that the prefix of attribute 'Old is an entity when it
5030 -- is potentially unevaluated (6.1.1 (27/3)).
5034 then
5035 Uneval_Old_Msg;
5037 -- Detect a possible infinite recursion when the prefix denotes
5038 -- the related function.
5040 -- function Func (...) return ...
5041 -- with Post => Func'Old ...;
5043 -- The function may be specified in qualified form X.Y where X is
5044 -- a protected object and Y is a protected function. In that case
5045 -- ensure that the qualified form has an entity.
5049 then
5054 then
5061 -- The prefix of attribute 'Old may refer to a component of a
5062 -- formal parameter. In this case its expansion may generate
5063 -- actual subtypes that are referenced in an inner context and
5064 -- that must be elaborated within the subprogram itself. If the
5065 -- prefix includes a function call, it may involve finalization
5066 -- actions that should be inserted when the attribute has been
5067 -- rewritten as a declaration. Create a declaration for the prefix
5068 -- and insert it at the start of the enclosing subprogram. This is
5069 -- an expansion activity that has to be performed now to prevent
5070 -- out-of-order issues.
5072 -- This expansion is both harmful and not needed in SPARK mode,
5073 -- since the formal verification back end relies on the types of
5074 -- nodes (hence is not robust w.r.t. a change to base type here),
5075 -- and does not suffer from the out-of-order issue described
5076 -- above. Thus, this expansion is skipped in SPARK mode.
5078 -- The expansion is not relevant for discrete types, which will
5079 -- not generate extra declarations, and where use of the base type
5080 -- may lead to spurious errors if context is a case.
5096 ----------------------
5097 -- Overlaps_Storage --
5098 ----------------------
5101 Check_E1;
5103 -- Both arguments must be objects of any type
5111 ------------
5112 -- Output --
5113 ------------
5116 Check_E2;
5121 ------------------
5122 -- Partition_ID --
5123 ------------------
5126 Check_E0;
5130 Error_Attr_P
5133 -- The defining entity of prefix should not be declared inside a
5134 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
5138 then
5145 -------------------------
5146 -- Passed_By_Reference --
5147 -------------------------
5150 Check_E0;
5151 Check_Type;
5154 ------------------
5155 -- Pool_Address --
5156 ------------------
5159 Check_E0;
5162 ---------
5163 -- Pos --
5164 ---------
5167 Check_Discrete_Type;
5168 Check_E1;
5173 Check_SPARK_05_Restriction
5180 --------------
5181 -- Position --
5182 --------------
5185 Check_Component;
5188 ----------
5189 -- Pred --
5190 ----------
5193 Check_Scalar_Type;
5194 Check_E1;
5199 Check_SPARK_05_Restriction
5206 -- Since Pred works on the base type, we normally do no check for the
5207 -- floating-point case, since the base type is unconstrained. But we
5208 -- make an exception in Check_Float_Overflow mode.
5215 -- If not modular type, test for overflow check required
5217 else
5220 then
5225 --------------
5226 -- Priority --
5227 --------------
5229 -- Ada 2005 (AI-327): Dynamic ceiling priorities
5236 Check_E0;
5240 -- The prefix must be a protected object (AARM D.5.2 (2/2))
5247 then
5249 else
5255 -- Must be called from within a protected procedure or entry of the
5256 -- protected object.
5258 declare
5261 begin
5265 loop
5275 Validate_Non_Static_Attribute_Function_Call;
5277 -----------
5278 -- Range --
5279 -----------
5282 Check_Array_Or_Scalar_Type;
5283 Bad_Attribute_For_Predicate;
5288 then
5289 Error_Attr
5293 ------------
5294 -- Result --
5295 ------------
5298 function Denote_Same_Function
5301 -- Determine whether the entity of the prefix Pref_Id denotes the
5302 -- same entity as that of the related subprogram Spec_Id.
5304 --------------------------
5305 -- Denote_Same_Function --
5306 --------------------------
5308 function Denote_Same_Function
5311 is
5315 begin
5316 -- The prefix denotes the related subprogram
5321 -- Account for a special case when attribute 'Result appears in
5322 -- the postcondition of a generic function.
5324 -- generic
5325 -- function Gen_Func return ...
5326 -- with Post => Gen_Func'Result ...;
5328 -- When the generic function is instantiated, the Chars field of
5329 -- the instantiated prefix still denotes the name of the generic
5330 -- function. Note that any preemptive transformation is impossible
5331 -- without a proper analysis. The structure of the wrapper package
5332 -- is as follows:
5334 -- package Anon_Gen_Pack is
5335 -- <subtypes and renamings>
5336 -- function Subp_Decl return ...; -- (!)
5337 -- pragma Postcondition (Gen_Func'Result ...); -- (!)
5338 -- function Gen_Func ... renames Subp_Decl;
5339 -- end Anon_Gen_Pack;
5344 then
5350 then
5354 -- Account for a special case where a primitive of a tagged type
5355 -- inherits a class-wide postcondition from a parent type. In this
5356 -- case the prefix of attribute 'Result denotes the overriding
5357 -- primitive.
5363 -- Otherwise the prefix does not denote the related subprogram
5368 -- Local variables
5371 Modify_Tree_For_C
5378 -- Start of processing for Result
5380 begin
5381 -- The attribute reference is a primary. If any expressions follow,
5382 -- then the attribute reference is an indexable object. Transform the
5383 -- attribute into an indexed component and analyze it.
5388 Prefix =>
5399 -- The aspect or pragma where attribute 'Result resides should be
5400 -- associated with a subprogram declaration or a body. If this is not
5401 -- the case, then the aspect or pragma is illegal. Return as analysis
5402 -- cannot be carried out.
5404 -- The exception to this rule is when generating C since in this case
5405 -- postconditions are inlined.
5414 -- Attribute 'Result is part of a _Postconditions procedure. There is
5415 -- no need to perform the semantic checks below as they were already
5416 -- verified when the attribute was analyzed in its original context.
5417 -- Instead, rewrite the attribute as a reference to formal parameter
5418 -- _Result of the _Postconditions procedure.
5421 or else
5422 (In_Inlined_C_Postcondition
5424 then
5427 -- The type of formal parameter _Result is that of the function
5428 -- encapsulating the _Postconditions procedure. Resolution must
5429 -- be carried out against the function return type.
5433 -- Otherwise attribute 'Result appears in its original context and
5434 -- all semantic checks should be carried out.
5436 else
5437 -- Verify the legality of the prefix. It must denotes the entity
5438 -- of the related [generic] function.
5445 then
5448 -- Correct the prefix of the attribute when the context
5449 -- is a generic function.
5458 -- Otherwise the prefix denotes some unrelated function
5460 else
5462 Error_Attr
5466 -- Otherwise the prefix denotes some other form of subprogram
5467 -- entity.
5469 else
5470 Error_Attr
5475 -- Otherwise the prefix is illegal
5477 else
5484 ------------------
5485 -- Range_Length --
5486 ------------------
5489 Check_E0;
5490 Check_Discrete_Type;
5493 ----------
5494 -- Read --
5495 ----------
5498 Check_E2;
5504 ---------
5505 -- Ref --
5506 ---------
5509 Check_E1;
5514 then
5521 ---------------
5522 -- Remainder --
5523 ---------------
5526 Check_Floating_Point_Type_2;
5531 ---------------------
5532 -- Restriction_Set --
5533 ---------------------
5540 begin
5541 Check_E1;
5543 Check_System_Prefix;
5545 -- No_Dependence case
5553 Error_Attr;
5556 -- See if there is an entry already in the table. That's the
5557 -- case in which we can return True.
5562 then
5568 -- If not in the No_Dependence table, result is False
5572 -- In this case, we must ensure that the binder will reject any
5573 -- other unit in the partition that sets No_Dependence for this
5574 -- unit. We do that by making an entry in the special table kept
5575 -- for this purpose (if the entry is not there already).
5580 Restriction_Set_Dependences.Last
5581 loop
5589 -- Normal restriction case
5591 else
5596 else
5607 Error_Attr
5613 else
5621 -----------
5622 -- Round --
5623 -----------
5626 Check_E1;
5627 Check_Decimal_Fixed_Point_Type;
5630 -- Because the context is universal_real (3.5.10(12)) it is a
5631 -- legal context for a universal fixed expression. This is the
5632 -- only attribute whose functional description involves U_R.
5635 declare
5640 begin
5648 --------------
5649 -- Rounding --
5650 --------------
5653 Check_Floating_Point_Type_1;
5657 ---------------
5658 -- Safe_Emax --
5659 ---------------
5662 Check_Floating_Point_Type_0;
5665 ----------------
5666 -- Safe_First --
5667 ----------------
5670 Check_Floating_Point_Type_0;
5673 ----------------
5674 -- Safe_Large --
5675 ----------------
5678 Check_E0;
5679 Check_Real_Type;
5682 ---------------
5683 -- Safe_Last --
5684 ---------------
5687 Check_Floating_Point_Type_0;
5690 ----------------
5691 -- Safe_Small --
5692 ----------------
5695 Check_E0;
5696 Check_Real_Type;
5699 --------------------------
5700 -- Scalar_Storage_Order --
5701 --------------------------
5706 begin
5707 Check_E0;
5708 Check_Type;
5712 -- In GNAT mode, the attribute applies to generic types as well
5713 -- as composite types, and for non-composite types always returns
5714 -- the default bit order for the target.
5717 and then not In_Instance
5718 then
5719 Error_Attr_P
5725 else
5733 else
5744 -- Reset incorrect indication of staticness
5749 -----------
5750 -- Scale --
5751 -----------
5754 Check_E0;
5755 Check_Decimal_Fixed_Point_Type;
5758 -------------
5759 -- Scaling --
5760 -------------
5763 Check_Floating_Point_Type_2;
5767 ------------------
5768 -- Signed_Zeros --
5769 ------------------
5772 Check_Floating_Point_Type_0;
5775 ----------
5776 -- Size --
5777 ----------
5779 when Attribute_Size
5780 | Attribute_VADS_Size
5781 =>
5782 Check_E0;
5784 -- If prefix is parameterless function call, rewrite and resolve
5785 -- as such.
5789 then
5792 -- Similar processing for a protected function call
5796 then
5806 then
5811 then
5814 -- Some other compilers allow dubious use of X'???'Size
5816 elsif Relaxed_RM_Semantics
5818 then
5821 else
5825 Check_Not_Incomplete_Type;
5826 Check_Not_CPP_Type;
5829 -- If we are processing pragmas Compile_Time_Warning and Compile_
5830 -- Time_Errors after the back end has been called and this occurrence
5831 -- of 'Size is known at compile time then it is safe to perform this
5832 -- evaluation. Needed to perform the static evaluation of the full
5833 -- boolean expression of these pragmas.
5835 if In_Compile_Time_Warning_Or_Error
5840 then
5845 -----------
5846 -- Small --
5847 -----------
5850 Check_E0;
5851 Check_Real_Type;
5854 ------------------
5855 -- Storage_Pool --
5856 ------------------
5858 when Attribute_Storage_Pool
5859 | Attribute_Simple_Storage_Pool
5860 =>
5861 Check_E0;
5865 Error_Attr_P
5869 -- Set appropriate entity
5873 else
5879 Name_Simple_Storage_Pool_Type))
5880 then
5883 Error_Msg_N
5888 Rewrite
5895 -- In the Simple_Storage_Pool case, verify that the pool entity is
5896 -- actually of a simple storage pool type, and set the attribute's
5897 -- type to the pool object's type.
5899 else
5901 Name_Simple_Storage_Pool_Type))
5902 then
5903 Error_Attr_P
5911 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5912 -- Storage_Pool since this attribute is not defined for such
5913 -- types (RM E.2.3(22)).
5917 else
5921 ------------------
5922 -- Storage_Size --
5923 ------------------
5926 Check_E0;
5931 -- Use with tasks is an obsolescent feature
5937 Error_Attr_P
5943 then
5944 Check_Type;
5947 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5948 -- Storage_Size since this attribute is not defined for
5949 -- such types (RM E.2.3(22)).
5953 -- The prefix is allowed to be an implicit dereference of an
5954 -- access value designating a task.
5956 else
5957 Check_Task_Prefix;
5961 else
5965 ------------------
5966 -- Storage_Unit --
5967 ------------------
5972 -----------------
5973 -- Stream_Size --
5974 -----------------
5977 Check_E0;
5978 Check_Type;
5982 then
5984 else
5988 ---------------
5989 -- Stub_Type --
5990 ---------------
5993 Check_Type;
5994 Check_E0;
5998 -- For a real RACW [sub]type, use corresponding stub type
6002 New_Occurrence_Of
6005 -- For a generic type (that has been marked as an RACW using the
6006 -- Remote_Access_Type aspect or pragma), use a generic RACW stub
6007 -- type. Note that if the actual is not a remote access type, the
6008 -- instantiation will fail.
6010 else
6011 -- Note: we go to the underlying type here because the view
6012 -- returned by RTE (RE_RACW_Stub_Type) might be incomplete.
6015 New_Occurrence_Of
6019 else
6020 Error_Attr_P
6024 ----------
6025 -- Succ --
6026 ----------
6029 Check_Scalar_Type;
6030 Check_E1;
6035 Check_SPARK_05_Restriction
6042 -- Since Pred works on the base type, we normally do no check for the
6043 -- floating-point case, since the base type is unconstrained. But we
6044 -- make an exception in Check_Float_Overflow mode.
6051 -- If not modular type, test for overflow check required
6053 else
6056 then
6061 --------------------------------
6062 -- System_Allocator_Alignment --
6063 --------------------------------
6068 ---------
6069 -- Tag --
6070 ---------
6073 Check_E0;
6074 Check_Dereference;
6079 -- Next test does not apply to generated code why not, and what does
6080 -- the illegal reference mean???
6085 then
6086 Error_Attr_P
6091 -- The prefix cannot be an incomplete type. However, references to
6092 -- 'Tag can be generated when expanding interface conversions, and
6093 -- this is legal.
6096 Check_Not_Incomplete_Type;
6099 -- Set appropriate type
6103 -----------------
6104 -- Target_Name --
6105 -----------------
6111 begin
6112 Check_Standard_Prefix;
6127 ----------------
6128 -- Terminated --
6129 ----------------
6132 Check_E0;
6134 Check_Task_Prefix;
6136 ----------------
6137 -- To_Address --
6138 ----------------
6143 begin
6144 Check_E1;
6146 Check_System_Prefix;
6156 -- OK static expression case, check range and set appropriate type
6162 or else
6164 then
6168 -- In most cases the expression is a numeric literal or some other
6169 -- address expression, but if it is a declared constant it may be
6170 -- of a compatible type that must be left on the node.
6175 -- Set type to universal integer if negative
6180 -- Otherwise set type to Unsigned_64 to accommodate max values
6182 else
6190 ------------
6191 -- To_Any --
6192 ------------
6195 Check_E1;
6196 Check_PolyORB_Attribute;
6199 ----------------
6200 -- Truncation --
6201 ----------------
6204 Check_Floating_Point_Type_1;
6208 ----------------
6209 -- Type_Class --
6210 ----------------
6213 Check_E0;
6214 Check_Type;
6215 Check_Not_Incomplete_Type;
6218 --------------
6219 -- TypeCode --
6220 --------------
6223 Check_E0;
6224 Check_PolyORB_Attribute;
6227 --------------
6228 -- Type_Key --
6229 --------------
6236 -- The computed signature for the type
6239 -- To simplify the handling of mutually recursive types, follow a
6240 -- single dereference link in a composite type.
6243 -- Create a CRC integer from the declaration of the type. For a
6244 -- composite type, fold in the representation of its components in
6245 -- recursive fashion. We use directly the source representation of
6246 -- the types involved.
6248 ----------------------
6249 -- Compute_Type_Key --
6250 ----------------------
6260 -- Update CRC with the characters of one type declaration, or a
6261 -- representation pragma that applies to the type.
6263 -----------------------------
6264 -- Process_One_Declaration --
6265 -----------------------------
6268 begin
6269 -- Scan type declaration, skipping blanks
6278 -- Start of processing for Compute_Type_Key
6280 begin
6285 -- If the type is declared in Standard, there is no source, so
6286 -- just use its name.
6289 declare
6291 begin
6305 Process_One_Declaration;
6307 -- Recurse on relevant component types
6322 declare
6324 begin
6335 -- Fold in representation aspects for the type, which appear in
6336 -- the same source buffer. If the representation aspects are in
6337 -- a different source file, then skip them; they apply to some
6338 -- other type, perhaps one we're derived from.
6348 Process_One_Declaration;
6357 -- Start of processing for Type_Key
6359 begin
6360 Check_E0;
6361 Check_Type;
6363 Start_String;
6366 -- Copy all characters in Full_Name but the trailing NUL
6372 -- Compute CRC and convert it to string one character at a time, so
6373 -- as not to use Image within the compiler.
6391 -----------------------
6392 -- Unbiased_Rounding --
6393 -----------------------
6396 Check_Floating_Point_Type_1;
6400 ----------------------
6401 -- Unchecked_Access --
6402 ----------------------
6409 Analyze_Access_Attribute;
6410 Check_Not_Incomplete_Type;
6412 -------------------------
6413 -- Unconstrained_Array --
6414 -------------------------
6417 Check_E0;
6418 Check_Type;
6419 Check_Not_Incomplete_Type;
6423 ------------------------------
6424 -- Universal_Literal_String --
6425 ------------------------------
6427 -- This is a GNAT specific attribute whose prefix must be a named
6428 -- number where the expression is either a single numeric literal,
6429 -- or a numeric literal immediately preceded by a minus sign. The
6430 -- result is equivalent to a string literal containing the text of
6431 -- the literal as it appeared in the source program with a possible
6432 -- leading minus sign.
6435 Check_E0;
6439 then
6442 else
6443 declare
6449 begin
6455 else
6460 Error_Attr
6464 -- Build string literal corresponding to source literal text
6466 Start_String;
6480 -- Now we rewrite the attribute with the string literal
6489 -------------------------
6490 -- Unrestricted_Access --
6491 -------------------------
6493 -- This is a GNAT specific attribute which is like Access except that
6494 -- all scope checks and checks for aliased views are omitted. It is
6495 -- documented as being equivalent to the use of the Address attribute
6496 -- followed by an unchecked conversion to the target access type.
6500 -- If from source, deal with relevant restrictions
6508 then
6517 -- It might seem reasonable to call Address_Checks here to apply the
6518 -- same set of semantic checks that we enforce for 'Address (after
6519 -- all we document Unrestricted_Access as being equivalent to the
6520 -- use of Address followed by an Unchecked_Conversion). However, if
6521 -- we do enable these checks, we get multiple failures in both the
6522 -- compiler run-time and in our regression test suite, so we leave
6523 -- out these checks for now. To be investigated further some time???
6525 -- Address_Checks;
6527 -- Now complete analysis using common access processing
6529 Analyze_Access_Attribute;
6531 ------------
6532 -- Update --
6533 ------------
6537 -- The common type of a multiple component update for a record
6540 -- A list used in the resolution of a record update. It contains the
6541 -- entities of all record components processed so far.
6544 -- Analyze and resolve array_component_association Assoc against the
6545 -- index of array type P_Type.
6548 -- Analyze and resolve record_component_association Comp against
6549 -- record type P_Type.
6551 ------------------------------------
6552 -- Analyze_Array_Component_Update --
6553 ------------------------------------
6562 begin
6563 -- The current association contains a sequence of indexes denoting
6564 -- an element of a multidimensional array:
6566 -- (Index_1, ..., Index_N)
6568 -- Examine each individual index and resolve it against the proper
6569 -- index type of the array.
6575 -- The use of others is illegal (SPARK RM 4.4.1(12))
6578 Error_Attr
6581 -- Otherwise analyze and resolve all indexes
6583 else
6592 -- Detect a case where the association either lacks an
6593 -- index or contains an extra index.
6596 Error_Msg_N
6604 -- The current association denotes either a single component or a
6605 -- range of components of a one dimensional array:
6607 -- 1, 2 .. 5
6609 -- Resolve the index or its high and low bounds (if range) against
6610 -- the proper index type of the array.
6612 else
6622 -- The use of others is illegal (SPARK RM 4.4.1(12))
6625 Error_Attr
6628 -- The index denotes a range of elements
6637 -- Add a range check to ensure that the bounds of the
6638 -- range are within the index type when this cannot be
6639 -- determined statically.
6649 -- Otherwise the index denotes a single element
6651 else
6654 -- Add a range check to ensure that the index is within
6655 -- the index type when it is not possible to determine
6656 -- this statically.
6668 -------------------------------------
6669 -- Analyze_Record_Component_Update --
6670 -------------------------------------
6677 begin
6678 -- Find the discriminant or component whose name corresponds to
6679 -- Comp. A simple character comparison is sufficient because all
6680 -- visible names within a record type are unique.
6686 -- Decorate the component reference by setting its entity
6687 -- and type for resolution purposes.
6697 -- Diagnose an illegal reference
6701 Error_Attr
6708 -- Mark this component as processed
6710 else
6715 -- The update aggregate mentions an entity that does not belong to
6716 -- the record type.
6718 else
6722 -- Verify the consistency of types when the current component is
6723 -- part of a miltiple component update.
6725 -- Comp_1, ..., Comp_N => <value>
6730 -- Save the type of the first component reference as the
6731 -- remaning references (if any) must resolve to this type.
6737 Error_Msg_N
6743 -- Local variables
6748 -- Start of processing for Update
6750 begin
6751 Check_E1;
6758 then
6768 -- Inspect the update aggregate, looking at all the associations and
6769 -- choices. Perform the following checks:
6771 -- 1) Legality of "others" in all cases
6772 -- 2) Legality of <>
6773 -- 3) Component legality for arrays
6774 -- 4) Component legality for records
6776 -- The remaining checks are performed on the expanded attribute
6781 -- The use of <> is illegal (SPARK RM 4.4.1(1))
6784 Error_Attr
6787 -- Otherwise process the association
6789 else
6797 -- Reset the common type used in a multiple component update
6798 -- as we are processing the contents of a new association.
6807 -- The use of others is illegal (SPARK RM 4.4.1(5))
6810 Error_Attr
6813 -- The name of a record component cannot appear in any
6814 -- other form.
6816 else
6817 Error_Msg_N
6829 -- The type of attribute 'Update is that of the prefix
6836 ---------
6837 -- Val --
6838 ---------
6841 Check_E1;
6842 Check_Discrete_Type;
6847 Check_SPARK_05_Restriction
6851 -- Note, we need a range check in general, but we wait for the
6852 -- Resolve call to do this, since we want to let Eval_Attribute
6853 -- have a chance to find an static illegality first.
6858 -----------
6859 -- Valid --
6860 -----------
6863 Check_E0;
6865 -- Ignore check for object if we have a 'Valid reference generated
6866 -- by the expanded code, since in some cases valid checks can occur
6867 -- on items that are names, but are not objects (e.g. attributes).
6877 -- If the attribute appears within the subtype's own predicate
6878 -- function, then issue a warning that this will cause infinite
6879 -- recursion.
6881 declare
6884 begin
6886 Error_Msg_N
6894 -------------------
6895 -- Valid_Scalars --
6896 -------------------
6899 Check_E0;
6903 -- Following checks are only for source types
6907 Error_Attr_P
6911 -- Not allowed for unchecked union type
6914 Error_Attr_P
6919 -----------
6920 -- Value --
6921 -----------
6924 Check_SPARK_05_Restriction_On_Attribute;
6925 Check_E1;
6926 Check_Scalar_Type;
6928 -- Case of enumeration type
6930 -- When an enumeration type appears in an attribute reference, all
6931 -- literals of the type are marked as referenced. This must only be
6932 -- done if the attribute reference appears in the current source.
6933 -- Otherwise the information on references may differ between a
6934 -- normal compilation and one that performs inlining.
6938 then
6941 -- Mark all enumeration literals as referenced, since the use of
6942 -- the Value attribute can implicitly reference any of the
6943 -- literals of the enumeration base type.
6945 declare
6947 begin
6955 -- Set Etype before resolving expression because expansion of
6956 -- expression may require enclosing type. Note that the type
6957 -- returned by 'Value is the base type of the prefix type.
6960 Validate_Non_Static_Attribute_Function_Call;
6962 -- Check restriction No_Fixed_IO
6966 then
6970 ----------------
6971 -- Value_Size --
6972 ----------------
6975 Check_E0;
6976 Check_Type;
6977 Check_Not_Incomplete_Type;
6980 -------------
6981 -- Version --
6982 -------------
6985 Check_E0;
6986 Check_Program_Unit;
6989 ------------------
6990 -- Wchar_T_Size --
6991 ------------------
6996 ----------------
6997 -- Wide_Image --
6998 ----------------
7003 ---------------------
7004 -- Wide_Wide_Image --
7005 ---------------------
7010 ----------------
7011 -- Wide_Value --
7012 ----------------
7015 Check_SPARK_05_Restriction_On_Attribute;
7016 Check_E1;
7017 Check_Scalar_Type;
7019 -- Set Etype before resolving expression because expansion
7020 -- of expression may require enclosing type.
7023 Validate_Non_Static_Attribute_Function_Call;
7025 -- Check restriction No_Fixed_IO
7029 then
7033 ---------------------
7034 -- Wide_Wide_Value --
7035 ---------------------
7038 Check_E1;
7039 Check_Scalar_Type;
7041 -- Set Etype before resolving expression because expansion
7042 -- of expression may require enclosing type.
7045 Validate_Non_Static_Attribute_Function_Call;
7047 -- Check restriction No_Fixed_IO
7051 then
7055 ---------------------
7056 -- Wide_Wide_Width --
7057 ---------------------
7060 Check_E0;
7061 Check_Scalar_Type;
7064 ----------------
7065 -- Wide_Width --
7066 ----------------
7069 Check_SPARK_05_Restriction_On_Attribute;
7070 Check_E0;
7071 Check_Scalar_Type;
7074 -----------
7075 -- Width --
7076 -----------
7079 Check_SPARK_05_Restriction_On_Attribute;
7080 Check_E0;
7081 Check_Scalar_Type;
7084 ---------------
7085 -- Word_Size --
7086 ---------------
7091 -----------
7092 -- Write --
7093 -----------
7096 Check_E2;
7103 -- In SPARK certain attributes (see below) depend on Tasking_State.
7104 -- Ensure that the entity is available for gnat2why by loading it.
7105 -- See SPARK RM 9(18) for the relevant rule.
7108 declare
7111 begin
7113 when Attribute_Callable
7114 | Attribute_Caller
7115 | Attribute_Count
7116 | Attribute_Terminated
7117 =>
7126 -- All errors raise Bad_Attribute, so that we get out before any further
7127 -- damage occurs when an error is detected (for example, if we check for
7128 -- one attribute expression, and the check succeeds, we want to be able
7129 -- to proceed securely assuming that an expression is in fact present.
7131 -- Note: we set the attribute analyzed in this case to prevent any
7132 -- attempt at reanalysis which could generate spurious error msgs.
7134 exception
7141 --------------------
7142 -- Eval_Attribute --
7143 --------------------
7152 -- The type imposed by the context
7155 -- First expression, or Empty if none
7158 -- Second expression, or Empty if none
7161 -- Entity denoted by prefix
7164 -- The type of the prefix
7167 -- The base type of the prefix type
7170 -- The root type of the prefix type
7173 -- True if the result is Static. This is set by the general processing
7174 -- to true if the prefix is static, and all expressions are static. It
7175 -- can be reset as processing continues for particular attributes. This
7176 -- flag can still be True if the reference raises a constraint error.
7177 -- Is_Static_Expression (N) is set to follow this value as it is set
7178 -- and we could always reference this, but it is convenient to have a
7179 -- simple short name to use, since it is frequently referenced.
7182 -- Expressions for low and high bounds of type or array index referenced
7183 -- by First, Last, or Length attribute for array, set by Set_Bounds.
7186 -- Constraint error node used if we have an attribute reference has
7187 -- an argument that raises a constraint error. In this case we replace
7188 -- the attribute with a raise constraint_error node. This is important
7189 -- processing, since otherwise gigi might see an attribute which it is
7190 -- unprepared to deal with.
7193 -- If Bound is a reference to a discriminant of a task or protected type
7194 -- occurring within the object's body, rewrite attribute reference into
7195 -- a reference to the corresponding discriminal. Use for the expansion
7196 -- of checks against bounds of entry family index subtypes.
7199 -- In case where the attribute is not foldable, the expressions, if
7200 -- any, of the attribute, are in a non-static context. This procedure
7201 -- performs the required additional checks.
7204 -- Determines if the given type has compile time known bounds. Note
7205 -- that we enter the case statement even in cases where the prefix
7206 -- type does NOT have known bounds, so it is important to guard any
7207 -- attempt to evaluate both bounds with a call to this function.
7210 -- This procedure is called when the attribute N has a non-static
7211 -- but compile time known value given by Val. It includes the
7212 -- necessary checks for out of range values.
7215 -- Computes the Fore value for the current attribute prefix, which is
7216 -- known to be a static fixed-point type. Used by Fore and Width.
7219 -- Returns the Mantissa value for the prefix type
7222 -- Used for First, Last and Length attributes applied to an array or
7223 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
7224 -- and high bound expressions for the index referenced by the attribute
7225 -- designator (i.e. the first index if no expression is present, and the
7226 -- N'th index if the value N is present as an expression). Also used for
7227 -- First and Last of scalar types and for First_Valid and Last_Valid.
7228 -- Static is reset to False if the type or index type is not statically
7229 -- constrained.
7232 -- Verify that the prefix of a potentially static array attribute
7233 -- satisfies the conditions of 4.9 (14).
7235 -----------------------------------
7236 -- Check_Concurrent_Discriminant --
7237 -----------------------------------
7241 -- The concurrent (task or protected) type
7243 begin
7247 then
7252 -- Find discriminant of original concurrent type, and use
7253 -- its current discriminal, which is the renaming within
7254 -- the task/protected body.
7257 New_Occurrence_Of
7263 -----------------------
7264 -- Check_Expressions --
7265 -----------------------
7269 begin
7277 ----------------------------------
7278 -- Compile_Time_Known_Attribute --
7279 ----------------------------------
7284 begin
7287 -- Check that result is in bounds of the type if it is static
7293 Apply_Compile_Time_Constraint_Error
7299 else
7304 -------------------------------
7305 -- Compile_Time_Known_Bounds --
7306 -------------------------------
7309 begin
7310 return
7312 and then
7316 ----------------
7317 -- Fore_Value --
7318 ----------------
7320 -- Note that the Fore calculation is based on the actual values
7321 -- of the bounds, and does not take into account possible rounding.
7332 begin
7333 -- Bounds are given in terms of small units, so first compute
7334 -- proper values as reals.
7339 -- Loop to compute proper value if more than one digit required
7349 --------------
7350 -- Mantissa --
7351 --------------
7353 -- Table of mantissa values accessed by function Computed using
7354 -- the relation:
7356 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
7358 -- where D is T'Digits (RM83 3.5.7)
7403 begin
7404 return
7408 ----------------
7409 -- Set_Bounds --
7410 ----------------
7417 begin
7418 -- For a string literal subtype, we have to construct the bounds.
7419 -- Valid Ada code never applies attributes to string literals, but
7420 -- it is convenient to allow the expander to generate attribute
7421 -- references of this type (e.g. First and Last applied to a string
7422 -- literal).
7424 -- Note that the whole point of the E_String_Literal_Subtype is to
7425 -- avoid this construction of bounds, but the cases in which we
7426 -- have to materialize them are rare enough that we don't worry.
7428 -- The low bound is simply the low bound of the base type. The
7429 -- high bound is computed from the length of the string and this
7430 -- low bound.
7436 Hi_Bound :=
7438 Intval =>
7445 -- For non-array case, just get bounds of scalar type
7450 -- For a fixed-point type, we must freeze to get the attributes
7451 -- of the fixed-point type set now so we can reference them.
7457 then
7461 -- For array case, get type of proper index
7463 else
7466 else
7475 -- If no index type, get out (some other error occurred, and
7476 -- we don't have enough information to complete the job).
7487 -- A discrete range in an index constraint is allowed to be a
7488 -- subtype indication. This is syntactically a pain, but should
7489 -- not propagate to the entity for the corresponding index subtype.
7490 -- After checking that the subtype indication is legal, the range
7491 -- of the subtype indication should be transfered to the entity.
7492 -- The attributes for the bounds should remain the simple retrievals
7493 -- that they are now.
7498 -- If subtype is non-static, result is definitely non-static
7504 -- Subtype is static, does it raise CE?
7511 -------------------------------
7512 -- Statically_Denotes_Entity --
7513 -------------------------------
7518 begin
7521 else
7525 return
7530 -- Start of processing for Eval_Attribute
7532 begin
7533 -- Initialize result as non-static, will be reset if appropriate
7538 -- Acquire first two expressions (at the moment, no attributes take more
7539 -- than two expressions in any case).
7544 else
7549 -- Special processing for Enabled attribute. This attribute has a very
7550 -- special prefix, and the easiest way to avoid lots of special checks
7551 -- to protect this special prefix from causing trouble is to deal with
7552 -- this attribute immediately and be done with it.
7556 -- We skip evaluation if the expander is not active. This is not just
7557 -- an optimization. It is of key importance that we not rewrite the
7558 -- attribute in a generic template, since we want to pick up the
7559 -- setting of the check in the instance, Testing Expander_Active
7560 -- might seem an easy way of doing this, but we need to account for
7561 -- ASIS needs, so check explicitly for a generic context.
7564 declare
7568 begin
7572 else
7576 else
7587 -- Attribute 'Img applied to a static enumeration value is static, and
7588 -- we will do the folding right here (things get confused if we let this
7589 -- case go through the normal circuitry).
7595 then
7596 declare
7600 begin
7601 Start_String;
7615 -- Special processing for cases where the prefix is an object. For this
7616 -- purpose, a string literal counts as an object (attributes of string
7617 -- literals can only appear in generated code).
7621 -- For Component_Size, the prefix is an array object, and we apply
7622 -- the attribute to the type of the object. This is allowed for both
7623 -- unconstrained and constrained arrays, since the bounds have no
7624 -- influence on the value of this attribute.
7629 -- For Enum_Rep, evaluation depends on the nature of the prefix and
7630 -- the optional argument.
7635 declare
7637 -- The enumeration-type expression of interest
7639 begin
7640 -- P'Enum_Rep case
7643 E_Enumeration_Literal)
7644 then
7647 -- Enum_Type'Enum_Rep (E1) case
7652 -- Otherwise the attribute must be expanded into a
7653 -- conversion and evaluated at run time.
7655 else
7656 Check_Expressions;
7660 -- We can fold if the expression is an enumeration
7661 -- literal, or if it denotes a constant whose value
7662 -- is known at compile time.
7666 E_Enumeration_Literal
7667 or else
7670 N_Object_Declaration
7671 and then Compile_Time_Known_Value
7673 then
7675 else
7676 Check_Expressions;
7681 -- Otherwise the attribute is illegal, do not attempt to perform
7682 -- any kind of folding.
7684 else
7688 -- For First and Last, the prefix is an array object, and we apply
7689 -- the attribute to the type of the array, but we need a constrained
7690 -- type for this, so we use the actual subtype if available.
7694 Id = Attribute_Length
7695 then
7696 declare
7699 begin
7703 -- If we have an unconstrained type we cannot fold
7705 else
7706 Check_Expressions;
7711 -- For Size, give size of object if available, otherwise we
7712 -- cannot fold Size.
7717 then
7721 else
7722 Check_Expressions;
7726 -- For Alignment, give size of object if available, otherwise we
7727 -- cannot fold Alignment.
7732 then
7736 else
7737 Check_Expressions;
7741 -- For Lock_Free, we apply the attribute to the type of the object.
7742 -- This is allowed since we have already verified that the type is a
7743 -- protected type.
7748 -- No other attributes for objects are folded
7750 else
7751 Check_Expressions;
7755 -- Cases where P is not an object. Cannot do anything if P is not the
7756 -- name of an entity.
7759 Check_Expressions;
7762 -- Otherwise get prefix entity
7764 else
7768 -- If we are asked to evaluate an attribute where the prefix is a
7769 -- non-frozen generic actual type whose RM_Size is still set to zero,
7770 -- then abandon the effort.
7777 -- However, the attribute Unconstrained_Array must be evaluated,
7778 -- since it is documented to be a static attribute (and can for
7779 -- example appear in a Compile_Time_Warning pragma). The frozen
7780 -- status of the type does not affect its evaluation.
7783 then
7787 -- At this stage P_Entity is the entity to which the attribute
7788 -- is to be applied. This is usually simply the entity of the
7789 -- prefix, except in some cases of attributes for objects, where
7790 -- as described above, we apply the attribute to the object type.
7792 -- Here is where we make sure that static attributes are properly
7793 -- marked as such. These are attributes whose prefix is a static
7794 -- scalar subtype, whose result is scalar, and whose arguments, if
7795 -- present, are static scalar expressions. Note that such references
7796 -- are static expressions even if they raise Constraint_Error.
7798 -- For example, Boolean'Pos (1/0 = 0) is a static expression, even
7799 -- though evaluating it raises constraint error. This means that a
7800 -- declaration like:
7802 -- X : constant := (if True then 1 else Boolean'Pos (1/0 = 0));
7804 -- is legal, since here this expression appears in a statically
7805 -- unevaluated position, so it does not actually raise an exception.
7811 and then
7815 and then
7819 then
7824 -- First foldable possibility is a scalar or array type (RM 4.9(7))
7825 -- that is not generic (generic types are eliminated by RM 4.9(25)).
7826 -- Note we allow non-static non-generic types at this stage as further
7827 -- described below.
7832 then
7835 -- Second foldable possibility is an array object (RM 4.9(8))
7840 then
7843 -- If the entity is an array constant with an unconstrained nominal
7844 -- subtype then get the type from the initial value. If the value has
7845 -- been expanded into assignments, there is no expression and the
7846 -- attribute reference remains dynamic.
7848 -- We could do better here and retrieve the type ???
7852 then
7855 else
7860 -- Definite must be folded if the prefix is not a generic type, that
7861 -- is to say if we are within an instantiation. Same processing applies
7862 -- to the GNAT attributes Atomic_Always_Lock_Free, Has_Discriminants,
7863 -- Lock_Free, Type_Class, Has_Tagged_Value, and Unconstrained_Array.
7875 then
7878 -- We can fold 'Size applied to a type if the size is known (as happens
7879 -- for a size from an attribute definition clause). At this stage, this
7880 -- can happen only for types (e.g. record types) for which the size is
7881 -- always non-static. We exclude generic types from consideration (since
7882 -- they have bogus sizes set within templates).
7888 then
7892 -- We can fold 'Alignment applied to a type if the alignment is known
7893 -- (as happens for an alignment from an attribute definition clause).
7894 -- At this stage, this can happen only for types (e.g. record types) for
7895 -- which the size is always non-static. We exclude generic types from
7896 -- consideration (since they have bogus sizes set within templates).
7902 then
7906 -- If this is an access attribute that is known to fail accessibility
7907 -- check, rewrite accordingly.
7911 then
7918 -- No other cases are foldable (they certainly aren't static, and at
7919 -- the moment we don't try to fold any cases other than the ones above).
7921 else
7922 Check_Expressions;
7926 -- If either attribute or the prefix is Any_Type, then propagate
7927 -- Any_Type to the result and don't do anything else at all.
7932 then
7937 -- Scalar subtype case. We have not yet enforced the static requirement
7938 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
7939 -- of non-static attribute references (e.g. S'Digits for a non-static
7940 -- floating-point type, which we can compute at compile time).
7942 -- Note: this folding of non-static attributes is not simply a case of
7943 -- optimization. For many of the attributes affected, Gigi cannot handle
7944 -- the attribute and depends on the front end having folded them away.
7946 -- Note: although we don't require staticness at this stage, we do set
7947 -- the Static variable to record the staticness, for easy reference by
7948 -- those attributes where it matters (e.g. Succ and Pred), and also to
7949 -- be used to ensure that non-static folded things are not marked as
7950 -- being static (a check that is done right at the end).
7955 -- If the root type or base type is generic, then we cannot fold. This
7956 -- test is needed because subtypes of generic types are not always
7957 -- marked as being generic themselves (which seems odd???)
7961 then
7973 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
7974 -- since we can't do anything with unconstrained arrays. In addition,
7975 -- only the First, Last and Length attributes are possibly static.
7977 -- Atomic_Always_Lock_Free, Definite, Has_Access_Values,
7978 -- Has_Discriminants, Has_Tagged_Values, Lock_Free, Type_Class, and
7979 -- Unconstrained_Array are again exceptions, because they apply as well
7980 -- to unconstrained types.
7982 -- In addition Component_Size is an exception since it is possibly
7983 -- foldable, even though it is never static, and it does apply to
7984 -- unconstrained arrays. Furthermore, it is essential to fold this
7985 -- in the packed case, since otherwise the value will be incorrect.
7995 Id = Attribute_Component_Size
7996 then
8005 then
8006 Check_Expressions;
8010 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
8011 -- scalar case, we hold off on enforcing staticness, since there are
8012 -- cases which we can fold at compile time even though they are not
8013 -- static (e.g. 'Length applied to a static index, even though other
8014 -- non-static indexes make the array type non-static). This is only
8015 -- an optimization, but it falls out essentially free, so why not.
8016 -- Again we compute the variable Static for easy reference later
8017 -- (note that no array attributes are static in Ada 83).
8019 -- We also need to set Static properly for subsequent legality checks
8020 -- which might otherwise accept non-static constants in contexts
8021 -- where they are not legal.
8023 Static :=
8027 declare
8030 begin
8033 -- The expression is static if the array type is constrained
8034 -- by given bounds, and not by an initial expression. Constant
8035 -- strings are static in any case.
8038 Static :=
8054 -- If however the index type is generic, or derived from
8055 -- one, attributes cannot be folded.
8059 then
8068 -- Check any expressions that are present. Note that these expressions,
8069 -- depending on the particular attribute type, are either part of the
8070 -- attribute designator, or they are arguments in a case where the
8071 -- attribute reference returns a function. In the latter case, the
8072 -- rule in (RM 4.9(22)) applies and in particular requires the type
8073 -- of the expressions to be scalar in order for the attribute to be
8074 -- considered to be static.
8076 declare
8079 begin
8084 -- If expression is not static, then the attribute reference
8085 -- result certainly cannot be static.
8096 -- If the result is not known at compile time, or is not of
8097 -- a scalar type, then the result is definitely not static,
8098 -- so we can quit now.
8102 then
8103 -- An odd special case, if this is a Pos attribute, this
8104 -- is where we need to apply a range check since it does
8105 -- not get done anywhere else.
8113 Check_Expressions;
8116 -- If the expression raises a constraint error, then so does
8117 -- the attribute reference. We keep going in this case because
8118 -- we are still interested in whether the attribute reference
8119 -- is static even if it is not static.
8134 -- Deal with the case of a static attribute reference that raises
8135 -- constraint error. The Raises_Constraint_Error flag will already
8136 -- have been set, and the Static flag shows whether the attribute
8137 -- reference is static. In any case we certainly can't fold such an
8138 -- attribute reference.
8140 -- Note that the rewriting of the attribute node with the constraint
8141 -- error node is essential in this case, because otherwise Gigi might
8142 -- blow up on one of the attributes it never expects to see.
8144 -- The constraint_error node must have the type imposed by the context,
8145 -- to avoid spurious errors in the enclosing expression.
8148 CE_Node :=
8153 Check_Expressions;
8159 -- At this point we have a potentially foldable attribute reference.
8160 -- If Static is set, then the attribute reference definitely obeys
8161 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
8162 -- folded. If Static is not set, then the attribute may or may not
8163 -- be foldable, and the individual attribute processing routines
8164 -- test Static as required in cases where it makes a difference.
8166 -- In the case where Static is not set, we do know that all the
8167 -- expressions present are at least known at compile time (we assumed
8168 -- above that if this was not the case, then there was no hope of static
8169 -- evaluation). However, we did not require that the bounds of the
8170 -- prefix type be compile time known, let alone static). That's because
8171 -- there are many attributes that can be computed at compile time on
8172 -- non-static subtypes, even though such references are not static
8173 -- expressions.
8175 -- For VAX float, the root type is an IEEE type. So make sure to use the
8176 -- base type instead of the root-type for floating point attributes.
8180 -- Attributes related to Ada 2012 iterators; nothing to evaluate for
8181 -- these.
8183 when Attribute_Constant_Indexing
8184 | Attribute_Default_Iterator
8185 | Attribute_Implicit_Dereference
8186 | Attribute_Iterator_Element
8187 | Attribute_Iterable
8188 | Attribute_Variable_Indexing
8189 =>
8192 -- Internal attributes used to deal with Ada 2012 delayed aspects.
8193 -- These were already rejected by the parser. Thus they shouldn't
8194 -- appear here.
8199 --------------
8200 -- Adjacent --
8201 --------------
8204 Fold_Ureal
8206 Eval_Fat.Adjacent
8208 Static);
8210 ---------
8211 -- Aft --
8212 ---------
8217 ---------------
8218 -- Alignment --
8219 ---------------
8224 begin
8225 -- Fold if alignment is set and not otherwise
8232 -----------------------------
8233 -- Atomic_Always_Lock_Free --
8234 -----------------------------
8236 -- Atomic_Always_Lock_Free attribute is a Boolean, thus no need to fold
8237 -- here.
8240 declare
8242 Boolean_Literals
8243 (Support_Atomic_Primitives_On_Target
8246 begin
8249 -- Analyze and resolve as boolean. Note that this attribute is a
8250 -- static attribute in GNAT.
8257 ---------
8258 -- Bit --
8259 ---------
8261 -- Bit can never be folded
8266 ------------------
8267 -- Body_Version --
8268 ------------------
8270 -- Body_version can never be static
8275 -------------
8276 -- Ceiling --
8277 -------------
8280 Fold_Ureal
8283 --------------------
8284 -- Component_Size --
8285 --------------------
8292 -------------
8293 -- Compose --
8294 -------------
8297 Fold_Ureal
8300 Static);
8302 -----------------
8303 -- Constrained --
8304 -----------------
8306 -- Constrained is never folded for now, there may be cases that
8307 -- could be handled at compile time. To be looked at later.
8311 -- The expander might fold it and set the static flag accordingly,
8312 -- but with expansion disabled (as in ASIS), it remains as an
8313 -- attribute reference, and this reference is not static.
8318 ---------------
8319 -- Copy_Sign --
8320 ---------------
8323 Fold_Ureal
8325 Eval_Fat.Copy_Sign
8327 Static);
8329 --------------
8330 -- Definite --
8331 --------------
8338 -----------
8339 -- Delta --
8340 -----------
8345 ------------
8346 -- Denorm --
8347 ------------
8350 Fold_Uint
8353 ---------------------
8354 -- Descriptor_Size --
8355 ---------------------
8360 ------------
8361 -- Digits --
8362 ------------
8367 ----------
8368 -- Emax --
8369 ----------
8373 -- Ada 83 attribute is defined as (RM83 3.5.8)
8375 -- T'Emax = 4 * T'Mantissa
8379 --------------
8380 -- Enum_Rep --
8381 --------------
8386 begin
8387 -- The attribute appears in the form:
8389 -- Enum_Typ'Enum_Rep (Const)
8390 -- Enum_Typ'Enum_Rep (Enum_Lit)
8395 -- Otherwise the prefix denotes a constant or enumeration literal:
8397 -- Const'Enum_Rep
8398 -- Enum_Lit'Enum_Rep
8400 else
8404 -- For an enumeration type with a non-standard representation use
8405 -- the Enumeration_Rep field of the proper constant. Note that this
8406 -- will not work for types Character/Wide_[Wide-]Character, since no
8407 -- real entities are created for the enumeration literals, but that
8408 -- does not matter since these two types do not have non-standard
8409 -- representations anyway.
8413 then
8416 -- For enumeration types with standard representations and all other
8417 -- cases (i.e. all integer and modular types), Enum_Rep is equivalent
8418 -- to Pos.
8420 else
8425 --------------
8426 -- Enum_Val --
8427 --------------
8432 begin
8433 -- We have something like Enum_Type'Enum_Val (23), so search for a
8434 -- corresponding value in the list of Enum_Rep values for the type.
8437 loop
8446 Apply_Compile_Time_Constraint_Error
8448 CE_Range_Check_Failed,
8455 -------------
8456 -- Epsilon --
8457 -------------
8461 -- Ada 83 attribute is defined as (RM83 3.5.8)
8463 -- T'Epsilon = 2.0**(1 - T'Mantissa)
8467 --------------
8468 -- Exponent --
8469 --------------
8475 -----------------------
8476 -- Finalization_Size --
8477 -----------------------
8482 -----------
8483 -- First --
8484 -----------
8487 Set_Bounds;
8492 else
8496 else
8500 -----------------
8501 -- First_Valid --
8502 -----------------
8507 then
8508 declare
8511 begin
8514 else
8519 else
8520 Set_Bounds;
8524 -----------------
8525 -- Fixed_Value --
8526 -----------------
8531 -----------
8532 -- Floor --
8533 -----------
8536 Fold_Ureal
8539 ----------
8540 -- Fore --
8541 ----------
8548 --------------
8549 -- Fraction --
8550 --------------
8553 Fold_Ureal
8556 -----------------------
8557 -- Has_Access_Values --
8558 -----------------------
8565 -----------------------
8566 -- Has_Discriminants --
8567 -----------------------
8574 ----------------------
8575 -- Has_Same_Storage --
8576 ----------------------
8581 -----------------------
8582 -- Has_Tagged_Values --
8583 -----------------------
8590 --------------
8591 -- Identity --
8592 --------------
8597 -----------
8598 -- Image --
8599 -----------
8601 -- Image is a scalar attribute, but is never static, because it is
8602 -- not a static function (having a non-scalar argument (RM 4.9(22))
8603 -- However, we can constant-fold the image of an enumeration literal
8604 -- if names are available.
8610 and then not Global_Discard_Names
8611 then
8612 declare
8615 begin
8616 Start_String;
8627 -------------------
8628 -- Integer_Value --
8629 -------------------
8631 -- We never try to fold Integer_Value (though perhaps we could???)
8636 -------------------
8637 -- Invalid_Value --
8638 -------------------
8640 -- Invalid_Value is a scalar attribute that is never static, because
8641 -- the value is by design out of range.
8646 -----------
8647 -- Large --
8648 -----------
8652 -- For fixed-point, we use the identity:
8654 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
8659 Left_Opnd =>
8661 Left_Opnd =>
8663 Left_Opnd =>
8665 Right_Opnd =>
8671 Right_Opnd =>
8676 -- Floating-point (Ada 83 compatibility)
8678 else
8679 -- Ada 83 attribute is defined as (RM83 3.5.8)
8681 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
8683 -- where
8685 -- T'Emax = 4 * T'Mantissa
8687 Fold_Ureal
8693 ---------------
8694 -- Lock_Free --
8695 ---------------
8700 begin
8703 -- Analyze and resolve as boolean. Note that this attribute is a
8704 -- static attribute in GNAT.
8711 ----------
8712 -- Last --
8713 ----------
8716 Set_Bounds;
8721 else
8725 else
8729 ----------------
8730 -- Last_Valid --
8731 ----------------
8736 then
8737 declare
8740 begin
8743 else
8748 else
8749 Set_Bounds;
8753 ------------------
8754 -- Leading_Part --
8755 ------------------
8758 Fold_Ureal
8760 Eval_Fat.Leading_Part
8762 Static);
8764 ------------
8765 -- Length --
8766 ------------
8771 begin
8772 -- If any index type is a formal type, or derived from one, the
8773 -- bounds are not static. Treating them as static can produce
8774 -- spurious warnings or improper constant folding.
8785 Set_Bounds;
8787 -- For two compile time values, we can compute length
8791 then
8794 Static);
8797 -- One more case is where Hi_Bound and Lo_Bound are compile-time
8798 -- comparable, and we can figure out the difference between them.
8800 declare
8803 begin
8804 case
8805 Compile_Time_Compare
8807 is
8825 ----------------
8826 -- Loop_Entry --
8827 ----------------
8829 -- Loop_Entry acts as an alias of a constant initialized to the prefix
8830 -- of the said attribute at the point of entry into the related loop. As
8831 -- such, the attribute reference does not need to be evaluated because
8832 -- the prefix is the one that is evaluted.
8837 -------------
8838 -- Machine --
8839 -------------
8842 Fold_Ureal
8844 Eval_Fat.Machine
8846 Static);
8848 ------------------
8849 -- Machine_Emax --
8850 ------------------
8855 ------------------
8856 -- Machine_Emin --
8857 ------------------
8862 ----------------------
8863 -- Machine_Mantissa --
8864 ----------------------
8869 -----------------------
8870 -- Machine_Overflows --
8871 -----------------------
8875 -- Always true for fixed-point
8880 -- Floating point case
8882 else
8885 Static);
8888 -------------------
8889 -- Machine_Radix --
8890 -------------------
8896 then
8898 else
8902 -- All floating-point type always have radix 2
8904 else
8908 ----------------------
8909 -- Machine_Rounding --
8910 ----------------------
8912 -- Note: for the folding case, it is fine to treat Machine_Rounding
8913 -- exactly the same way as Rounding, since this is one of the allowed
8914 -- behaviors, and performance is not an issue here. It might be a bit
8915 -- better to give the same result as it would give at run time, even
8916 -- though the non-determinism is certainly permitted.
8919 Fold_Ureal
8922 --------------------
8923 -- Machine_Rounds --
8924 --------------------
8928 -- Always False for fixed-point
8933 -- Else yield proper floating-point result
8935 else
8936 Fold_Uint
8938 Static);
8941 ------------------
8942 -- Machine_Size --
8943 ------------------
8945 -- Note: Machine_Size is identical to Object_Size
8950 begin
8956 --------------
8957 -- Mantissa --
8958 --------------
8962 -- Fixed-point mantissa
8966 -- Compile time foldable case
8969 and then
8971 then
8972 -- The calculation of the obsolete Ada 83 attribute Mantissa
8973 -- is annoying, because of AI00143, quoted here:
8975 -- !question 84-01-10
8977 -- Consider the model numbers for F:
8979 -- type F is delta 1.0 range -7.0 .. 8.0;
8981 -- The wording requires that F'MANTISSA be the SMALLEST
8982 -- integer number for which each bound of the specified
8983 -- range is either a model number or lies at most small
8984 -- distant from a model number. This means F'MANTISSA
8985 -- is required to be 3 since the range -7.0 .. 7.0 fits
8986 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
8987 -- number, namely, 7. Is this analysis correct? Note that
8988 -- this implies the upper bound of the range is not
8989 -- represented as a model number.
8991 -- !response 84-03-17
8993 -- The analysis is correct. The upper and lower bounds for
8994 -- a fixed point type can lie outside the range of model
8995 -- numbers.
8997 declare
9004 begin
9010 -- If the Bound is exactly a model number, i.e. a multiple
9011 -- of Small, then we back it off by one to get the integer
9012 -- value that must be representable.
9018 -- Now find corresponding size = Mantissa value
9028 else
9029 -- The case of dynamic bounds cannot be evaluated at compile
9030 -- time. Instead we use a runtime routine (see Exp_Attr).
9035 -- Floating-point Mantissa
9037 else
9041 ---------
9042 -- Max --
9043 ---------
9047 Fold_Ureal
9049 else
9053 ----------------------------------
9054 -- Max_Alignment_For_Allocation --
9055 ----------------------------------
9057 -- Max_Alignment_For_Allocation is usually the Alignment. However,
9058 -- arrays are allocated with dope, so we need to take into account both
9059 -- the alignment of the array, which comes from the component alignment,
9060 -- and the alignment of the dope. Also, if the alignment is unknown, we
9061 -- use the max (it's OK to be pessimistic).
9065 begin
9068 then
9075 ----------------------------------
9076 -- Max_Size_In_Storage_Elements --
9077 ----------------------------------
9079 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
9080 -- Storage_Unit boundary. We can fold any cases for which the size
9081 -- is known by the front end.
9087 System_Storage_Unit,
9088 Static);
9091 --------------------
9092 -- Mechanism_Code --
9093 --------------------
9100 begin
9104 else
9120 ---------
9121 -- Min --
9122 ---------
9126 Fold_Ureal
9128 else
9129 Fold_Uint
9133 ---------
9134 -- Mod --
9135 ---------
9138 Fold_Uint
9141 -----------
9142 -- Model --
9143 -----------
9146 Fold_Ureal
9149 ----------------
9150 -- Model_Emin --
9151 ----------------
9156 -------------------
9157 -- Model_Epsilon --
9158 -------------------
9163 --------------------
9164 -- Model_Mantissa --
9165 --------------------
9170 -----------------
9171 -- Model_Small --
9172 -----------------
9177 -------------
9178 -- Modulus --
9179 -------------
9184 --------------------
9185 -- Null_Parameter --
9186 --------------------
9188 -- Cannot fold, we know the value sort of, but the whole point is
9189 -- that there is no way to talk about this imaginary value except
9190 -- by using the attribute, so we leave it the way it is.
9195 -----------------
9196 -- Object_Size --
9197 -----------------
9199 -- The Object_Size attribute for a type returns the Esize of the
9200 -- type and can be folded if this value is known.
9205 begin
9211 ----------------------
9212 -- Overlaps_Storage --
9213 ----------------------
9218 -------------------------
9219 -- Passed_By_Reference --
9220 -------------------------
9222 -- Scalar types are never passed by reference
9227 ---------
9228 -- Pos --
9229 ---------
9234 ----------
9235 -- Pred --
9236 ----------
9240 -- Floating-point case
9243 Fold_Ureal
9246 -- Fixed-point case
9249 Fold_Ureal
9252 -- Modular integer case (wraps)
9257 -- Other scalar cases
9259 else
9265 then
9266 Apply_Compile_Time_Constraint_Error
9268 CE_Overflow_Check_Failed,
9272 Check_Expressions;
9279 -----------
9280 -- Range --
9281 -----------
9283 -- No processing required, because by this stage, Range has been
9284 -- replaced by First .. Last, so this branch can never be taken.
9289 ------------------
9290 -- Range_Length --
9291 ------------------
9296 begin
9297 Set_Bounds;
9299 -- Can fold if both bounds are compile time known
9303 then
9305 UI_Max
9307 Static);
9310 -- One more case is where Hi_Bound and Lo_Bound are compile-time
9311 -- comparable, and we can figure out the difference between them.
9313 case Compile_Time_Compare
9315 is
9332 ---------
9333 -- Ref --
9334 ---------
9339 ---------------
9340 -- Remainder --
9341 ---------------
9347 begin
9349 Apply_Compile_Time_Constraint_Error
9351 CE_Overflow_Check_Failed,
9354 Check_Expressions;
9361 -----------------
9362 -- Restriction --
9363 -----------------
9369 -----------
9370 -- Round --
9371 -----------
9377 begin
9378 -- First we get the (exact result) in units of small
9382 -- Now round that exactly to an integer
9386 -- Finally the result is obtained by converting back to real
9391 --------------
9392 -- Rounding --
9393 --------------
9396 Fold_Ureal
9399 ---------------
9400 -- Safe_Emax --
9401 ---------------
9406 ----------------
9407 -- Safe_First --
9408 ----------------
9413 ----------------
9414 -- Safe_Large --
9415 ----------------
9419 Fold_Ureal
9421 else
9425 ---------------
9426 -- Safe_Last --
9427 ---------------
9432 ----------------
9433 -- Safe_Small --
9434 ----------------
9438 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
9439 -- for fixed-point, since is the same as Small, but we implement
9440 -- it for backwards compatibility.
9445 -- Ada 83 Safe_Small for floating-point cases
9447 else
9451 -----------
9452 -- Scale --
9453 -----------
9458 -------------
9459 -- Scaling --
9460 -------------
9463 Fold_Ureal
9465 Eval_Fat.Scaling
9467 Static);
9469 ------------------
9470 -- Signed_Zeros --
9471 ------------------
9474 Fold_Uint
9477 ----------
9478 -- Size --
9479 ----------
9481 -- Size attribute returns the RM size. All scalar types can be folded,
9482 -- as well as any types for which the size is known by the front end,
9483 -- including any type for which a size attribute is specified. This is
9484 -- one of the places where it is annoying that a size of zero means two
9485 -- things (zero size for scalars, unspecified size for non-scalars).
9487 when Attribute_Size
9488 | Attribute_VADS_Size
9489 =>
9493 begin
9496 then
9497 -- VADS_Size case
9500 declare
9503 begin
9504 -- If a size clause applies, then use the size from it.
9505 -- This is one of the rare cases where we can use the
9506 -- Size_Clause field for a subtype when Has_Size_Clause
9507 -- is False. Consider:
9509 -- type x is range 1 .. 64;
9510 -- for x'size use 12;
9511 -- subtype y is x range 0 .. 3;
9513 -- Here y has a size clause inherited from x, but
9514 -- normally it does not apply, and y'size is 2. However,
9515 -- y'VADS_Size is indeed 12 and not 2.
9519 then
9522 -- If no size is specified, then we simply use the object
9523 -- size in the VADS_Size case (e.g. Natural'Size is equal
9524 -- to Integer'Size, not one less).
9526 else
9531 -- Normal case (Size) in which case we want the RM_Size
9533 else
9539 -----------
9540 -- Small --
9541 -----------
9545 -- The floating-point case is present only for Ada 83 compatibility.
9546 -- Note that strictly this is an illegal addition, since we are
9547 -- extending an Ada 95 defined attribute, but we anticipate an
9548 -- ARG ruling that will permit this.
9552 -- Ada 83 attribute is defined as (RM83 3.5.8)
9554 -- T'Small = 2.0**(-T'Emax - 1)
9556 -- where
9558 -- T'Emax = 4 * T'Mantissa
9562 -- Normal Ada 95 fixed-point case
9564 else
9568 -----------------
9569 -- Stream_Size --
9570 -----------------
9575 ----------
9576 -- Succ --
9577 ----------
9580 -- Floating-point case
9583 Fold_Ureal
9586 -- Fixed-point case
9591 -- Modular integer case (wraps)
9596 -- Other scalar cases
9598 else
9604 then
9605 Apply_Compile_Time_Constraint_Error
9607 CE_Overflow_Check_Failed,
9611 Check_Expressions;
9613 else
9618 ----------------
9619 -- Truncation --
9620 ----------------
9623 Fold_Ureal
9626 Static);
9628 ----------------
9629 -- Type_Class --
9630 ----------------
9636 begin
9664 -- We treat protected types like task types. It would make more
9665 -- sense to have another enumeration value, but after all the
9666 -- whole point of this feature is to be exactly DEC compatible,
9667 -- and changing the type Type_Class would not meet this requirement.
9672 -- Not clear if there are any other possibilities, but if there
9673 -- are, then we will treat them as the address case.
9675 else
9682 -----------------------
9683 -- Unbiased_Rounding --
9684 -----------------------
9687 Fold_Ureal
9690 Static);
9692 -------------------------
9693 -- Unconstrained_Array --
9694 -------------------------
9699 begin
9701 Boolean_Literals (
9705 -- Analyze and resolve as boolean, note that this attribute is
9706 -- a static attribute in GNAT.
9713 -- Attribute Update is never static
9718 ---------------
9719 -- VADS_Size --
9720 ---------------
9722 -- Processing is shared with Size
9724 ---------
9725 -- Val --
9726 ---------
9730 or else
9732 then
9733 Apply_Compile_Time_Constraint_Error
9735 CE_Range_Check_Failed,
9738 Check_Expressions;
9741 else
9745 ----------------
9746 -- Value_Size --
9747 ----------------
9749 -- The Value_Size attribute for a type returns the RM size of the type.
9750 -- This an always be folded for scalar types, and can also be folded for
9751 -- non-scalar types if the size is set. This is one of the places where
9752 -- it is annoying that a size of zero means two things!
9757 begin
9763 -------------
9764 -- Version --
9765 -------------
9767 -- Version can never be static
9772 ----------------
9773 -- Wide_Image --
9774 ----------------
9776 -- Wide_Image is a scalar attribute, but is never static, because it
9777 -- is not a static function (having a non-scalar argument (RM 4.9(22))
9782 ---------------------
9783 -- Wide_Wide_Image --
9784 ---------------------
9786 -- Wide_Wide_Image is a scalar attribute but is never static, because it
9787 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
9792 ---------------------
9793 -- Wide_Wide_Width --
9794 ---------------------
9796 -- Processing for Wide_Wide_Width is combined with Width
9798 ----------------
9799 -- Wide_Width --
9800 ----------------
9802 -- Processing for Wide_Width is combined with Width
9804 -----------
9805 -- Width --
9806 -----------
9808 -- This processing also handles the case of Wide_[Wide_]Width
9810 when Attribute_Width
9811 | Attribute_Wide_Width
9812 | Attribute_Wide_Wide_Width
9813 =>
9816 -- Floating-point types
9820 -- Width is zero for a null range (RM 3.5 (38))
9824 then
9827 else
9828 -- For floating-point, we have +N.dddE+nnn where length
9829 -- of ddd is determined by type'Digits - 1, but is one
9830 -- if Digits is one (RM 3.5 (33)).
9832 -- nnn is set to 2 for Short_Float and Float (32 bit
9833 -- floats), and 3 for Long_Float and Long_Long_Float.
9834 -- For machines where Long_Long_Float is the IEEE
9835 -- extended precision type, the exponent takes 4 digits.
9837 declare
9841 begin
9846 else
9854 -- Fixed-point types
9858 -- Width is zero for a null range (RM 3.5 (38))
9862 then
9865 -- The non-null case depends on the specific real type
9867 else
9868 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
9870 Fold_Uint
9872 Static);
9875 -- Discrete types
9877 else
9878 declare
9888 begin
9889 -- Empty ranges
9894 -- Width for types derived from Standard.Character
9895 -- and Standard.Wide_[Wide_]Character.
9900 -- Set W larger if needed
9904 -- All wide characters look like Hex_hhhhhhhh
9908 -- No need to compute this more than once
9912 else
9915 -- Test for all cases where Character'Image
9916 -- yields an image that is longer than three
9917 -- characters. First the cases of Reserved_xxx
9918 -- names (length = 12).
9921 when Reserved_128
9922 | Reserved_129
9923 | Reserved_132
9924 | Reserved_153
9925 =>
9928 when BS
9929 | CR
9930 | EM
9931 | FF
9932 | FS
9933 | GS
9934 | HT
9935 | LF
9936 | MW
9937 | PM
9938 | RI
9939 | RS
9940 | SI
9941 | SO
9942 | ST
9943 | US
9944 | VT
9945 =>
9948 when ACK
9949 | APC
9950 | BEL
9951 | BPH
9952 | CAN
9953 | CCH
9954 | CSI
9955 | DC1
9956 | DC2
9957 | DC3
9958 | DC4
9959 | DCS
9960 | DEL
9961 | DLE
9962 | ENQ
9963 | EOT
9964 | EPA
9965 | ESA
9966 | ESC
9967 | ETB
9968 | ETX
9969 | HTJ
9970 | HTS
9971 | NAK
9972 | NBH
9973 | NEL
9974 | NUL
9975 | OSC
9976 | PLD
9977 | PLU
9978 | PU1
9979 | PU2
9980 | SCI
9981 | SOH
9982 | SOS
9983 | SPA
9984 | SS2
9985 | SS3
9986 | SSA
9987 | STS
9988 | STX
9989 | SUB
9990 | SYN
9991 | VTS
9992 =>
9996 | No_Break_Space .. LC_Y_Diaeresis
9997 =>
9998 -- Special case of soft hyphen in Ada 2005
10002 then
10004 else
10013 -- Width for types derived from Standard.Boolean
10018 else
10022 -- Width for integer types
10033 -- User declared enum type with discard names
10037 -- If range is null, result is zero, that has already
10038 -- been dealt with, so what we need is the power of ten
10039 -- that accommodates the Pos of the largest value, which
10040 -- is the high bound of the range + one for the space.
10049 -- Only remaining possibility is user declared enum type
10050 -- with normal case of Discard_Names not active.
10052 else
10059 -- Only pay attention to in range characters
10063 then
10064 -- For Width case, use decoded name
10070 -- For Wide_[Wide_]Width, use encoded name, and
10071 -- then adjust for the encoding.
10073 else
10076 -- Character literals are always of length 3
10081 -- Otherwise loop to adjust for upper/wide chars
10083 else
10108 -- The following attributes denote functions that cannot be folded
10110 when Attribute_From_Any
10111 | Attribute_To_Any
10112 | Attribute_TypeCode
10113 =>
10116 -- The following attributes can never be folded, and furthermore we
10117 -- should not even have entered the case statement for any of these.
10118 -- Note that in some cases, the values have already been folded as
10119 -- a result of the processing in Analyze_Attribute or earlier in
10120 -- this procedure.
10122 when Attribute_Abort_Signal
10123 | Attribute_Access
10124 | Attribute_Address
10125 | Attribute_Address_Size
10126 | Attribute_Asm_Input
10127 | Attribute_Asm_Output
10128 | Attribute_Base
10129 | Attribute_Bit_Order
10130 | Attribute_Bit_Position
10131 | Attribute_Callable
10132 | Attribute_Caller
10133 | Attribute_Class
10134 | Attribute_Code_Address
10135 | Attribute_Compiler_Version
10136 | Attribute_Count
10137 | Attribute_Default_Bit_Order
10138 | Attribute_Default_Scalar_Storage_Order
10139 | Attribute_Deref
10140 | Attribute_Elaborated
10141 | Attribute_Elab_Body
10142 | Attribute_Elab_Spec
10143 | Attribute_Elab_Subp_Body
10144 | Attribute_Enabled
10145 | Attribute_External_Tag
10146 | Attribute_Fast_Math
10147 | Attribute_First_Bit
10148 | Attribute_Img
10149 | Attribute_Input
10150 | Attribute_Last_Bit
10151 | Attribute_Library_Level
10152 | Attribute_Maximum_Alignment
10153 | Attribute_Old
10154 | Attribute_Output
10155 | Attribute_Partition_ID
10156 | Attribute_Pool_Address
10157 | Attribute_Position
10158 | Attribute_Priority
10159 | Attribute_Read
10160 | Attribute_Result
10161 | Attribute_Scalar_Storage_Order
10162 | Attribute_Simple_Storage_Pool
10163 | Attribute_Storage_Pool
10164 | Attribute_Storage_Size
10165 | Attribute_Storage_Unit
10166 | Attribute_Stub_Type
10167 | Attribute_System_Allocator_Alignment
10168 | Attribute_Tag
10169 | Attribute_Target_Name
10170 | Attribute_Terminated
10171 | Attribute_To_Address
10172 | Attribute_Type_Key
10173 | Attribute_Unchecked_Access
10174 | Attribute_Universal_Literal_String
10175 | Attribute_Unrestricted_Access
10176 | Attribute_Valid
10177 | Attribute_Valid_Scalars
10178 | Attribute_Value
10179 | Attribute_Wchar_T_Size
10180 | Attribute_Wide_Value
10181 | Attribute_Wide_Wide_Value
10182 | Attribute_Word_Size
10183 | Attribute_Write
10184 =>
10188 -- At the end of the case, one more check. If we did a static evaluation
10189 -- so that the result is now a literal, then set Is_Static_Expression
10190 -- in the constant only if the prefix type is a static subtype. For
10191 -- non-static subtypes, the folding is still OK, but not static.
10193 -- An exception is the GNAT attribute Constrained_Array which is
10194 -- defined to be a static attribute in all cases.
10197 N_Real_Literal,
10198 N_Character_Literal,
10199 N_String_Literal)
10202 then
10205 -- If this is still an attribute reference, then it has not been folded
10206 -- and that means that its expressions are in a non-static context.
10209 Check_Expressions;
10211 -- Note: the else case not covered here are odd cases where the
10212 -- processing has transformed the attribute into something other
10213 -- than a constant. Nothing more to do in such cases.
10215 else
10220 ------------------------------
10221 -- Is_Anonymous_Tagged_Base --
10222 ------------------------------
10224 function Is_Anonymous_Tagged_Base
10227 is
10228 begin
10229 return
10230 Anon = Current_Scope
10235 --------------------------------
10236 -- Name_Implies_Lvalue_Prefix --
10237 --------------------------------
10241 begin
10245 -----------------------
10246 -- Resolve_Attribute --
10247 -----------------------
10261 -- Error, or warning within an instance, if the static accessibility
10262 -- rules of 3.10.2 are violated.
10264 function Declared_Within_Generic_Unit
10267 -- Returns True if Declared_Entity is declared within the declarative
10268 -- region of Generic_Unit; otherwise returns False.
10270 ---------------------------
10271 -- Accessibility_Message --
10272 ---------------------------
10277 begin
10278 -- In an instance, this is a runtime check, but one we
10279 -- know will fail, so generate an appropriate warning.
10283 Error_Msg_F
10292 else
10295 -- Check for case where we have a missing access definition
10298 and then
10300 N_Index_Or_Discriminant_Constraint)
10301 then
10305 loop
10310 Error_Msg_NE
10319 ----------------------------------
10320 -- Declared_Within_Generic_Unit --
10321 ----------------------------------
10323 function Declared_Within_Generic_Unit
10326 is
10329 begin
10335 -- We have to step to the scope of the generic's entity, because
10336 -- otherwise we'll just get back the same generic.
10338 Generic_Encloser :=
10339 Enclosing_Generic_Unit
10346 -- Start of processing for Resolve_Attribute
10348 begin
10349 -- If error during analysis, no point in continuing, except for array
10350 -- types, where we get better recovery by using unconstrained indexes
10351 -- than nothing at all (see Check_Array_Type).
10358 then
10362 -- If attribute was universal type, reset to actual type
10366 then
10370 -- Remaining processing depends on attribute
10374 ------------
10375 -- Access --
10376 ------------
10378 -- For access attributes, if the prefix denotes an entity, it is
10379 -- interpreted as a name, never as a call. It may be overloaded,
10380 -- in which case resolution uses the profile of the context type.
10381 -- Otherwise prefix must be resolved.
10383 when Attribute_Access
10384 | Attribute_Unchecked_Access
10385 | Attribute_Unrestricted_Access
10386 =>
10387 -- Note possible modification if we have a variable
10390 declare
10395 -- Skip this for the case of Unrestricted_Access occuring in
10396 -- the context of a Valid check, since this otherwise leads
10397 -- to a missed warning (the Valid check does not really
10398 -- modify!) If this case, Note will be reset to False.
10400 -- Skip it as well if the type is an Acccess_To_Constant,
10401 -- given that no use of the value can modify the prefix.
10403 begin
10406 then
10413 then
10427 -- The following comes from a query concerning improper use of
10428 -- universal_access in equality tests involving anonymous access
10429 -- types. Another good reason for 'Ref, but for now disable the
10430 -- test, which breaks several filed tests???
10435 then
10440 -- Case where prefix is an entity name
10444 -- Deal with case where prefix itself is overloaded
10452 -- The prefix is definitely NOT overloaded anymore at
10453 -- this point, so we reset the Is_Overloaded flag to
10454 -- avoid any confusion when reanalyzing the node.
10465 -- If Prefix is a subprogram name, this reference freezes,
10466 -- but not if within spec expression mode. The profile of
10467 -- the subprogram is not frozen at this point.
10473 -- If it is a type, there is nothing to resolve.
10474 -- If it is a subprogram, do not freeze its profile.
10475 -- If it is an object, complete its resolution.
10482 -- Nothing to do if prefix is a type name
10487 -- Otherwise non-overloaded other case, resolve the prefix
10489 else
10493 -- Some further error checks
10502 then
10507 Error_Msg_F
10511 -- An attempt to take 'Access of a function that renames an
10512 -- enumeration literal. Issue a specialized error message.
10517 then
10518 Error_Msg_F
10528 -- Assignments, return statements, components of aggregates,
10529 -- generic instantiations will require convention checks if
10530 -- the type is an access to subprogram. Given that there will
10531 -- also be accessibility checks on those, this is where the
10532 -- checks can eventually be centralized ???
10535 E_Access_Subprogram_Type,
10536 E_Anonymous_Access_Protected_Subprogram_Type,
10537 E_Anonymous_Access_Subprogram_Type)
10538 then
10539 -- Deal with convention mismatch
10543 then
10544 -- The rule in 6.3.1 (8) deserves a special error
10545 -- message.
10550 and then Inside_A_Generic
10551 then
10552 declare
10555 begin
10557 Error_Msg_FE
10561 Error_Msg_N
10566 else
10567 Error_Msg_FE
10575 then
10576 Error_Msg_FE
10581 else
10582 Check_Subtype_Conformant
10590 Error_Msg_F
10596 -- Check the static accessibility rule of 3.10.2(32).
10597 -- This rule also applies within the private part of an
10598 -- instantiation. This rule does not apply to anonymous
10599 -- access-to-subprogram types in access parameters.
10602 and then not In_Instance_Body
10603 and then
10608 then
10609 Error_Msg_F
10612 -- Check the restriction of 3.10.2(32) that disallows the
10613 -- access attribute within a generic body when the ultimate
10614 -- ancestor of the type of the attribute is declared outside
10615 -- of the generic unit and the subprogram is declared within
10616 -- that generic unit. This includes any such attribute that
10617 -- occurs within the body of a generic unit that is a child
10618 -- of the generic unit where the subprogram is declared.
10620 -- The rule also prohibits applying the attribute when the
10621 -- access type is a generic formal access type (since the
10622 -- level of the actual type is not known). This restriction
10623 -- does not apply when the attribute type is an anonymous
10624 -- access-to-subprogram type. Note that this check was
10625 -- revised by AI-229, because the original Ada 95 rule
10626 -- was too lax. The original rule only applied when the
10627 -- subprogram was declared within the body of the generic,
10628 -- which allowed the possibility of dangling references).
10629 -- The rule was also too strict in some cases, in that it
10630 -- didn't permit the access to be declared in the generic
10631 -- spec, whereas the revised rule does (as long as it's not
10632 -- a formal type).
10634 -- There are a couple of subtleties of the test for applying
10635 -- the check that are worth noting. First, we only apply it
10636 -- when the levels of the subprogram and access type are the
10637 -- same (the case where the subprogram is statically deeper
10638 -- was applied above, and the case where the type is deeper
10639 -- is always safe). Second, we want the check to apply
10640 -- within nested generic bodies and generic child unit
10641 -- bodies, but not to apply to an attribute that appears in
10642 -- the generic unit's specification. This is done by testing
10643 -- that the attribute's innermost enclosing generic body is
10644 -- not the same as the innermost generic body enclosing the
10645 -- generic unit where the subprogram is declared (we don't
10646 -- want the check to apply when the access attribute is in
10647 -- the spec and there's some other generic body enclosing
10648 -- generic). Finally, there's no point applying the check
10649 -- when within an instance, because any violations will have
10650 -- been caught by the compilation of the generic unit.
10652 -- We relax this check in Relaxed_RM_Semantics mode for
10653 -- compatibility with legacy code for use by Ada source
10654 -- code analyzers (e.g. CodePeer).
10657 and then not Relaxed_RM_Semantics
10658 and then not In_Instance
10662 Enclosing_Generic_Body
10667 E_Anonymous_Access_Subprogram_Type
10669 E_Anonymous_Access_Protected_Subprogram_Type
10670 then
10671 -- The attribute type's ultimate ancestor must be
10672 -- declared within the same generic unit as the
10673 -- subprogram is declared (including within another
10674 -- nested generic unit). The error message is
10675 -- specialized to say "ancestor" for the case where the
10676 -- access type is not its own ancestor, since saying
10677 -- simply "access type" would be very confusing.
10679 if not Declared_Within_Generic_Unit
10682 then
10683 Error_Msg_N
10685 N);
10688 Error_Msg_NE
10692 else
10693 Error_Msg_NE
10699 Error_Msg_NE
10704 -- If the ultimate ancestor of the attribute's type is
10705 -- a formal type, then the attribute is illegal because
10706 -- the actual type might be declared at a higher level.
10707 -- The error message is specialized to say "ancestor"
10708 -- for the case where the access type is not its own
10709 -- ancestor, since saying simply "access type" would be
10710 -- very confusing.
10714 Error_Msg_N
10716 N);
10717 else
10718 Error_Msg_N
10726 -- If this is a renaming, an inherited operation, or a
10727 -- subprogram instance, use the original entity. This may make
10728 -- the node type-inconsistent, so this transformation can only
10729 -- be done if the node will not be reanalyzed. In particular,
10730 -- if it is within a default expression, the transformation
10731 -- must be delayed until the default subprogram is created for
10732 -- it, when the enclosing subprogram is frozen.
10737 and then Expander_Active
10738 then
10745 then
10746 -- Protected operation. If operation is overloaded, must
10747 -- disambiguate. Prefix that denotes protected object itself
10748 -- is resolved with its own type.
10752 Error_Msg_F
10759 -- Implement check implied by 3.10.2 (18.1/2) : F.all'access is
10760 -- statically illegal if F is an anonymous access to subprogram.
10765 E_Anonymous_Access_Subprogram_Type
10766 then
10772 -- Use the designated type of the context to disambiguate
10773 -- Note that this was not strictly conformant to Ada 95,
10774 -- but was the implementation adopted by most Ada 95 compilers.
10775 -- The use of the context type to resolve an Access attribute
10776 -- reference is now mandated in AI-235 for Ada 2005.
10778 declare
10782 begin
10793 else
10797 -- X'Access is illegal if X denotes a constant and the access type
10798 -- is access-to-variable. Same for 'Unchecked_Access. The rule
10799 -- does not apply to 'Unrestricted_Access. If the reference is a
10800 -- default-initialized aggregate component for a self-referential
10801 -- type the reference is legal.
10806 and then
10810 = E_Anonymous_Access_Protected_Subprogram_Type
10814 then
10817 then
10818 -- Legality of a self-reference through an access
10819 -- attribute has been verified in Analyze_Access_Attribute.
10832 then
10833 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
10834 -- imported entity, and the non-limited view is visible, make
10835 -- use of it. If it is an incomplete subtype, use the base type
10836 -- in any case.
10840 then
10849 or else
10853 then
10854 -- Ada 2005 (AI-230): Check the accessibility of anonymous
10855 -- access types for stand-alone objects, record and array
10856 -- components, and return objects. For a component definition
10857 -- the level is the same of the enclosing composite type.
10862 -- Handle cases where Btyp is the anonymous access
10863 -- type of an Ada 2012 stand-alone object.
10866 N_Object_Declaration)
10867 and then
10870 then
10871 -- In an instance, this is a runtime check, but one we know
10872 -- will fail, so generate an appropriate warning. As usual,
10873 -- this kind of warning is an error in SPARK mode.
10877 Error_Msg_F
10886 else
10887 Error_Msg_F
10893 Error_Msg_F
10895 P);
10898 -- Check static matching rule of 3.10.2(27). Nominal subtype
10899 -- of the prefix must statically match the designated type.
10909 -- If the attribute is in the context of an access
10910 -- parameter, then the prefix is allowed to be of
10911 -- the class-wide type (by AI-127).
10916 then
10917 declare
10920 begin
10930 else
10931 Error_Msg_FE
10934 Error_Msg_FE
10942 or else
10945 then
10946 Error_Msg_FE
10948 Error_Msg_FE
10957 then
10958 Apply_Discriminant_Check
10962 -- Ada 2005 (AI-363): Require static matching when designated
10963 -- type has discriminants and a constrained partial view, since
10964 -- in general objects of such types are mutable, so we can't
10965 -- allow the access value to designate a constrained object
10966 -- (because access values must be assumed to designate mutable
10967 -- objects when designated type does not impose a constraint).
10974 and then
10976 or else
10977 not Object_Type_Has_Constrained_Partial_View
10980 then
10983 else
10984 Error_Msg_F
10990 then
10991 declare
10993 begin
10994 Error_Msg_N
10996 Error_Msg_N
10999 Error_Msg_N
11005 -- Check the static accessibility rule of 3.10.2(28). Note that
11006 -- this check is not performed for the case of an anonymous
11007 -- access type, since the access attribute is always legal
11008 -- in such a context.
11012 and then
11014 then
11015 Accessibility_Message;
11021 E_Anonymous_Access_Protected_Subprogram_Type)
11022 then
11025 then
11028 -- Check accessibility of protected object against that of the
11029 -- access type, but only on user code, because the expander
11030 -- creates access references for handlers. If the context is an
11031 -- anonymous_access_to_protected, there are no accessibility
11032 -- checks either. Omit check entirely for Unrestricted_Access.
11038 then
11039 Accessibility_Message;
11042 -- AI05-0225: If the context is not an access to protected
11043 -- function, the prefix must be a variable, given that it may
11044 -- be used subsequently in a protected call.
11049 then
11050 Error_Msg_N
11059 E_Anonymous_Access_Subprogram_Type)
11061 then
11065 -- The context cannot be a pool-specific type, but this is a
11066 -- legality rule, not a resolution rule, so it must be checked
11067 -- separately, after possibly disambiguation (see AI-245).
11071 then
11075 -- The context may be a constrained access type (however ill-
11076 -- advised such subtypes might be) so in order to generate a
11077 -- constraint check when needed set the type of the attribute
11078 -- reference to the base type of the context.
11082 -- Check for incorrect atomic/volatile reference (RM C.6(12))
11087 then
11088 Error_Msg_F
11094 then
11095 Error_Msg_F
11101 -- Check for aliased view. We allow a nonaliased prefix when in
11102 -- an instance because the prefix may have been a tagged formal
11103 -- object, which is defined to be aliased even when the actual
11104 -- might not be (other instance cases will have been caught in
11105 -- the generic). Similarly, within an inlined body we know that
11106 -- the attribute is legal in the original subprogram, therefore
11107 -- legal in the expansion.
11112 and then
11115 and then not In_Instance
11116 and then not In_Inlined_Body
11118 then
11119 -- Here we have a non-aliased view. This is illegal unless we
11120 -- have the case of Unrestricted_Access, where for now we allow
11121 -- this (we will reject later if expected type is access to an
11122 -- unconstrained array with a thin pointer).
11124 -- No need for an error message on a generated access reference
11125 -- for the controlling argument in a dispatching call: error
11126 -- will be reported when resolving the call.
11131 -- Check for unrestricted access where expected type is a thin
11132 -- pointer to an unconstrained array.
11136 then
11137 declare
11139 begin
11142 then
11143 Error_Msg_N
11145 Error_Msg_N
11153 -- Mark that address of entity is taken in case of
11154 -- 'Unrestricted_Access or in case of a subprogram.
11159 then
11163 -- Deal with possible elaboration check
11166 declare
11174 -- If the access has been taken and the body of the subprogram
11175 -- has not been see yet, indirect calls must be protected with
11176 -- elaboration checks. We have the proper elaboration machinery
11177 -- for subprograms declared in packages, but within a block or
11178 -- a subprogram the body will appear in the same declarative
11179 -- part, and we must insert a check in the eventual body itself
11180 -- using the elaboration flag that we generate now. The check
11181 -- is then inserted when the body is expanded. This processing
11182 -- is not needed for a stand alone expression function because
11183 -- the internally generated spec and body are always inserted
11184 -- as a pair in the same declarative list.
11186 begin
11187 if Expander_Active
11196 N_Expression_Function
11197 then
11198 -- Create elaboration variable for it
11204 -- Insert declaration for flag after subprogram
11205 -- declaration. Note that attribute reference may
11206 -- appear within a nested scope.
11211 Object_Definition =>
11213 Expression =>
11217 -- Taking the 'Access of an expression function freezes its
11218 -- expression (RM 13.14 10.3/3). This does not apply to an
11219 -- expression function that acts as a completion because the
11220 -- generated body is immediately analyzed and the expression
11221 -- is automatically frozen.
11225 then
11226 Subp_Body :=
11229 -- The body has already been analyzed when the expression
11230 -- function acts as a completion.
11235 -- Attribute 'Access may appear within the generated body
11236 -- of the expression function subject to the attribute:
11238 -- function F is (... F'Access ...);
11240 -- If the expression function is on the scope stack, then
11241 -- the body is currently being analyzed. Do not reanalyze
11242 -- it because this will lead to infinite recursion.
11247 -- If reference to the expression function appears in an
11248 -- inner scope, for example as an actual in an instance,
11249 -- this is not a freeze point either.
11254 -- Analyze the body of the expression function to freeze
11255 -- the expression. This takes care of the case where the
11256 -- 'Access is part of dispatch table initialization and
11257 -- the generated body of the expression function has not
11258 -- been analyzed yet.
11260 else
11267 -------------
11268 -- Address --
11269 -------------
11271 -- Deal with resolving the type for Address attribute, overloading
11272 -- is not permitted here, since there is no context to resolve it.
11274 when Attribute_Address
11275 | Attribute_Code_Address
11276 =>
11277 -- To be safe, assume that if the address of a variable is taken,
11278 -- it may be modified via this address, so note modification.
11286 then
11292 Error_Msg_F
11299 then
11302 then
11307 -- If this is the name of a derived subprogram, or that of a
11308 -- generic actual, the address is that of the original entity.
11313 then
11324 -- Arr (X .. Y)'address is identical to Arr (X)'address,
11325 -- even if the array is packed and the slice itself is not
11326 -- addressable. Transform the prefix into an indexed component.
11328 -- Note that the transformation is safe only if we know that
11329 -- the slice is non-null. That is because a null slice can have
11330 -- an out of bounds index value.
11332 -- Right now, gigi blows up if given 'Address on a slice as a
11333 -- result of some incorrect freeze nodes generated by the front
11334 -- end, and this covers up that bug in one case, but the bug is
11335 -- likely still there in the cases not handled by this code ???
11337 -- It's not clear what 'Address *should* return for a null
11338 -- slice with out of bounds indexes, this might be worth an ARG
11339 -- discussion ???
11341 -- One approach would be to do a length check unconditionally,
11342 -- and then do the transformation below unconditionally, but
11343 -- analyze with checks off, avoiding the problem of the out of
11344 -- bounds index. This approach would interpret the address of
11345 -- an out of bounds null slice as being the address where the
11346 -- array element would be if there was one, which is probably
11347 -- as reasonable an interpretation as any ???
11349 declare
11354 begin
11356 and then
11357 Not_Null_Range
11360 then
11361 Lo :=
11368 then
11371 else
11386 ------------------
11387 -- Body_Version --
11388 ------------------
11390 -- Prefix of Body_Version attribute can be a subprogram name which
11391 -- must not be resolved, since this is not a call.
11396 ------------
11397 -- Caller --
11398 ------------
11400 -- Prefix of Caller attribute is an entry name which must not
11401 -- be resolved, since this is definitely not an entry call.
11406 ------------------
11407 -- Code_Address --
11408 ------------------
11410 -- Shares processing with Address attribute
11412 -----------
11413 -- Count --
11414 -----------
11416 -- If the prefix of the Count attribute is an entry name it must not
11417 -- be resolved, since this is definitely not an entry call. However,
11418 -- if it is an element of an entry family, the index itself may
11419 -- have to be resolved because it can be a general expression.
11424 then
11425 declare
11428 begin
11434 ----------------
11435 -- Elaborated --
11436 ----------------
11438 -- Prefix of the Elaborated attribute is a subprogram name which
11439 -- must not be resolved, since this is definitely not a call. Note
11440 -- that it is a library unit, so it cannot be overloaded here.
11445 -------------
11446 -- Enabled --
11447 -------------
11449 -- Prefix of Enabled attribute is a check name, which must be treated
11450 -- specially and not touched by Resolve.
11455 ----------------
11456 -- Loop_Entry --
11457 ----------------
11459 -- Do not resolve the prefix of Loop_Entry, instead wait until the
11460 -- attribute has been expanded (see Expand_Loop_Entry_Attributes).
11461 -- The delay ensures that any generated checks or temporaries are
11462 -- inserted before the relocated prefix.
11467 --------------------
11468 -- Mechanism_Code --
11469 --------------------
11471 -- Prefix of the Mechanism_Code attribute is a function name
11472 -- which must not be resolved. Should we check for overloaded ???
11477 ------------------
11478 -- Partition_ID --
11479 ------------------
11481 -- Most processing is done in sem_dist, after determining the
11482 -- context type. Node is rewritten as a conversion to a runtime call.
11488 ------------------
11489 -- Pool_Address --
11490 ------------------
11495 -----------
11496 -- Range --
11497 -----------
11499 -- We replace the Range attribute node with a range expression whose
11500 -- bounds are the 'First and 'Last attributes applied to the same
11501 -- prefix. The reason that we do this transformation here instead of
11502 -- in the expander is that it simplifies other parts of the semantic
11503 -- analysis which assume that the Range has been replaced; thus it
11504 -- must be done even when in semantic-only mode (note that the RM
11505 -- specifically mentions this equivalence, we take care that the
11506 -- prefix is only evaluated once).
11513 begin
11520 HB :=
11526 LB :=
11532 -- Do not share the dimension indicator, if present. Even though
11533 -- it is a static constant, its source location may be modified
11534 -- when printing expanded code and node sharing will lead to chaos
11535 -- in Sprint.
11541 -- If the original was marked as Must_Not_Freeze (see code in
11542 -- Sem_Ch3.Make_Index), then make sure the rewriting does not
11543 -- freeze either.
11554 -- Preserve Sloc of prefix in the new bounds, so that the
11555 -- posted warning can be removed if we are within unreachable
11556 -- code.
11565 -- Ensure that the expanded range does not have side effects
11570 -- Normally after resolving attribute nodes, Eval_Attribute
11571 -- is called to do any possible static evaluation of the node.
11572 -- However, here since the Range attribute has just been
11573 -- transformed into a range expression it is no longer an
11574 -- attribute node and therefore the call needs to be avoided
11575 -- and is accomplished by simply returning from the procedure.
11580 ------------
11581 -- Result --
11582 ------------
11584 -- We will only come here during the prescan of a spec expression
11585 -- containing a Result attribute. In that case the proper Etype has
11586 -- already been set, and nothing more needs to be done here.
11591 ----------------------
11592 -- Unchecked_Access --
11593 ----------------------
11595 -- Processing is shared with Access
11597 -------------------------
11598 -- Unrestricted_Access --
11599 -------------------------
11601 -- Processing is shared with Access
11603 ------------
11604 -- Update --
11605 ------------
11607 -- Resolve aggregate components in component associations
11616 begin
11617 -- Set the Etype of the aggregate to that of the prefix, even
11618 -- though the aggregate may not be a proper representation of a
11619 -- value of the type (missing or duplicated associations, etc.)
11620 -- Complete resolution of the prefix. Note that in Ada 2012 it
11621 -- can be a qualified expression that is e.g. an aggregate.
11626 -- For an array type, resolve expressions with the component type
11627 -- of the array, and apply constraint checks when needed.
11635 -- For scalar array components set Do_Range_Check when
11636 -- needed. Constraint checking on non-scalar components
11637 -- is done in Aggregate_Constraint_Checks, but only if
11638 -- full analysis is enabled. These flags are not set in
11639 -- the front-end in GnatProve mode.
11644 then
11647 then
11650 else
11655 -- The choices in the association are static constants,
11656 -- or static aggregates each of whose components belongs
11657 -- to the proper index type. However, they must also
11658 -- belong to the index subtype (s) of the prefix, which
11659 -- may be a subtype (e.g. given by a slice).
11661 -- Choices may also be identifiers with no staticness
11662 -- requirements, in which case they must resolve to the
11663 -- index type.
11665 declare
11670 begin
11680 else
11699 -- For a record type, use type of each component, which is
11700 -- recorded during analysis.
11702 else
11710 then
11715 and then not Range_Checks_Suppressed
11717 then
11727 ---------
11728 -- Val --
11729 ---------
11731 -- Apply range check. Note that we did not do this during the
11732 -- analysis phase, since we wanted Eval_Attribute to have a
11733 -- chance at finding an illegal out of range value.
11737 -- Note that we do our own Eval_Attribute call here rather than
11738 -- use the common one, because we need to do processing after
11739 -- the call, as per above comment.
11743 -- Eval_Attribute may replace the node with a raise CE, or
11744 -- fold it to a constant. Obviously we only apply a scalar
11745 -- range check if this did not happen.
11749 then
11755 -------------
11756 -- Version --
11757 -------------
11759 -- Prefix of Version attribute can be a subprogram name which
11760 -- must not be resolved, since this is not a call.
11765 ----------------------
11766 -- Other Attributes --
11767 ----------------------
11769 -- For other attributes, resolve prefix unless it is a type. If
11770 -- the attribute reference itself is a type name ('Base and 'Class)
11771 -- then this is only legal within a task or protected record.
11778 -- If the attribute reference itself is a type name ('Base,
11779 -- 'Class) then this is only legal within a task or protected
11780 -- record. What is this all about ???
11785 then
11787 else
11788 Error_Msg_N
11793 -- For attributes whose argument may be a string, complete
11794 -- resolution of argument now. This avoids premature expansion
11795 -- (and the creation of transient scopes) before the attribute
11796 -- reference is resolved.
11811 -- If the prefix of the attribute is a class-wide type then it
11812 -- will be expanded into a dispatching call to a predefined
11813 -- primitive. Therefore we must check for potential violation
11814 -- of such restriction.
11821 -- Mark use clauses of the original prefix if the attribute is applied
11822 -- to an entity.
11826 then
11830 -- Normally the Freezing is done by Resolve but sometimes the Prefix
11831 -- is not resolved, in which case the freezing must be done now.
11833 -- For an elaboration check on a subprogram, we do not freeze its type.
11834 -- It may be declared in an unrelated scope, in particular in the case
11835 -- of a generic function whose type may remain unelaborated.
11840 else
11844 -- Finally perform static evaluation on the attribute reference
11850 ------------------------
11851 -- Set_Boolean_Result --
11852 ------------------------
11856 begin
11859 else
11864 -------------------------------
11865 -- Statically_Denotes_Object --
11866 -------------------------------
11871 begin
11878 then
11879 declare
11883 begin
11890 else
11898 then
11903 then
11912 else
11917 --------------------------------
11918 -- Stream_Attribute_Available --
11919 --------------------------------
11921 function Stream_Attribute_Available
11925 is
11928 -- Start of processing for Stream_Attribute_Available
11930 begin
11931 -- We need some comments in this body ???
11945 then
11952 then
11956 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
11961 then
11967 then
11971 -- Case of Read and Write: check for attribute definition clause that
11972 -- applies to an ancestor type.
11984 -- In Ada 95 mode, also consider a non-visible definition
11986 declare
11988 begin
11990 and then Stream_Attribute_Available