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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) 1992-2015, 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 ------------------------------------------------------------------------------
85 -- Synonyms to be used when these constants are used as Boolean values
88 -- Exception raised if an error is detected during attribute processing,
89 -- used so that we can abandon the processing so we don't run into
90 -- trouble with cascaded errors.
92 -- The following array is the list of attributes defined in the Ada 83 RM.
93 -- In Ada 83 mode, these are the only recognized attributes. In other Ada
94 -- modes all these attributes are recognized, even if removed in Ada 95.
97 Attribute_Address |
98 Attribute_Aft |
99 Attribute_Alignment |
100 Attribute_Base |
101 Attribute_Callable |
102 Attribute_Constrained |
103 Attribute_Count |
104 Attribute_Delta |
105 Attribute_Digits |
106 Attribute_Emax |
107 Attribute_Epsilon |
108 Attribute_First |
109 Attribute_First_Bit |
110 Attribute_Fore |
111 Attribute_Image |
112 Attribute_Large |
113 Attribute_Last |
114 Attribute_Last_Bit |
115 Attribute_Leading_Part |
116 Attribute_Length |
117 Attribute_Machine_Emax |
118 Attribute_Machine_Emin |
119 Attribute_Machine_Mantissa |
120 Attribute_Machine_Overflows |
121 Attribute_Machine_Radix |
122 Attribute_Machine_Rounds |
123 Attribute_Mantissa |
124 Attribute_Pos |
125 Attribute_Position |
126 Attribute_Pred |
127 Attribute_Range |
128 Attribute_Safe_Emax |
129 Attribute_Safe_Large |
130 Attribute_Safe_Small |
131 Attribute_Size |
132 Attribute_Small |
133 Attribute_Storage_Size |
134 Attribute_Succ |
135 Attribute_Terminated |
136 Attribute_Val |
137 Attribute_Value |
138 Attribute_Width => True,
139 others => False);
141 -- The following array is the list of attributes defined in the Ada 2005
142 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
143 -- but in Ada 95 they are considered to be implementation defined.
146 Attribute_Machine_Rounding |
147 Attribute_Mod |
148 Attribute_Priority |
149 Attribute_Stream_Size |
153 -- The following array is the list of attributes defined in the Ada 2012
154 -- RM which are not defined in Ada 2005. These are recognized in Ada 95
155 -- and Ada 2005 modes, but are considered to be implementation defined.
158 Attribute_First_Valid |
159 Attribute_Has_Same_Storage |
160 Attribute_Last_Valid |
161 Attribute_Max_Alignment_For_Allocation => True,
162 others => False);
164 -- The following array contains all attributes that imply a modification
165 -- of their prefixes or result in an access value. Such prefixes can be
166 -- considered as lvalues.
168 Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
170 Attribute_Access |
171 Attribute_Address |
172 Attribute_Input |
173 Attribute_Read |
174 Attribute_Unchecked_Access |
178 -----------------------
179 -- Local_Subprograms --
180 -----------------------
183 -- Performs compile time evaluation of attributes where possible, leaving
184 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
185 -- set, and replacing the node with a literal node if the value can be
186 -- computed at compile time. All static attribute references are folded,
187 -- as well as a number of cases of non-static attributes that can always
188 -- be computed at compile time (e.g. floating-point model attributes that
189 -- are applied to non-static subtypes). Of course in such cases, the
190 -- Is_Static_Expression flag will not be set on the resulting literal.
191 -- Note that the only required action of this procedure is to catch the
192 -- static expression cases as described in the RM. Folding of other cases
193 -- is done where convenient, but some additional non-static folding is in
194 -- Expand_N_Attribute_Reference in cases where this is more convenient.
196 function Is_Anonymous_Tagged_Base
199 -- For derived tagged types that constrain parent discriminants we build
200 -- an anonymous unconstrained base type. We need to recognize the relation
201 -- between the two when analyzing an access attribute for a constrained
202 -- component, before the full declaration for Typ has been analyzed, and
203 -- where therefore the prefix of the attribute does not match the enclosing
204 -- scope.
207 -- Rewrites node N with an occurrence of either Standard_False or
208 -- Standard_True, depending on the value of the parameter B. The
209 -- result is marked as a static expression.
211 -----------------------
212 -- Analyze_Attribute --
213 -----------------------
225 -- Type of prefix after analysis
228 -- Base type of prefix after analysis
230 -----------------------
231 -- Local Subprograms --
232 -----------------------
235 -- Semantic checks for valid use of Address attribute. This was made
236 -- a separate routine with the idea of using it for unrestricted access
237 -- which seems like it should follow the same rules, but that turned
238 -- out to be impractical. So now this is only used for Address.
241 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
242 -- Internally, Id distinguishes which of the three cases is involved.
244 procedure Analyze_Attribute_Old_Result
247 -- Common processing for attributes 'Old and 'Result. The routine checks
248 -- that the attribute appears in a postcondition-like aspect or pragma
249 -- associated with a suitable subprogram or a body. Flag Legal is set
250 -- when the above criteria are met. Spec_Id denotes the entity of the
251 -- subprogram [body] or Empty if the attribute is illegal.
254 -- Output error message for use of a predicate (First, Last, Range) not
255 -- allowed with a type that has predicates. If the type is a generic
256 -- actual, then the message is a warning, and we generate code to raise
257 -- program error with an appropriate reason. No error message is given
258 -- for internally generated uses of the attributes. This legality rule
259 -- only applies to scalar types.
262 -- Common procedure used by First, Last, Range attribute to check
263 -- that the prefix is a constrained array or scalar type, or a name
264 -- of an array object, and that an argument appears only if appropriate
265 -- (i.e. only in the array case).
268 -- Common semantic checks for all array attributes. Checks that the
269 -- prefix is a constrained array type or the name of an array object.
270 -- The error message for non-arrays is specialized appropriately.
273 -- Common semantic checks for Asm_Input and Asm_Output attributes
276 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
277 -- Position. Checks prefix is an appropriate selected component.
280 -- Check that prefix of attribute N is a decimal fixed-point type
283 -- If the prefix of attribute is an object of an access type, then
284 -- introduce an explicit dereference, and adjust P_Type accordingly.
287 -- Verify that prefix of attribute N is a discrete type
290 -- Check that no attribute arguments are present
293 -- Check that there are zero or one attribute arguments present
296 -- Check that exactly one attribute argument is present
299 -- Check that two attribute arguments are present
302 -- If the prefix type of 'Image is an enumeration type, set all its
303 -- literals as referenced, since the image function could possibly end
304 -- up referencing any of the literals indirectly. Same for Enum_Val.
305 -- Set the flag only if the reference is in the main code unit. Same
306 -- restriction when resolving 'Value; otherwise an improperly set
307 -- reference when analyzing an inlined body will lose a proper
308 -- warning on a useless with_clause.
311 -- Perform all checks for First_Valid and Last_Valid attributes
314 -- Verify that prefix of attribute N is a fixed type
317 -- Verify that prefix of attribute N is a fixed type and that
318 -- no attribute expressions are present
321 -- Verify that prefix of attribute N is a float type
324 -- Verify that prefix of attribute N is a float type and that
325 -- no attribute expressions are present
328 -- Verify that prefix of attribute N is a float type and that
329 -- exactly one attribute expression is present
332 -- Verify that prefix of attribute N is a float type and that
333 -- two attribute expressions are present
336 -- Issue an error in formal mode because attribute N is allowed
339 -- Verify that prefix of attribute N is an integer type
342 -- Verify that prefix of attribute N is a modular integer type
345 -- Check that P (the prefix of the attribute) is not an CPP type
346 -- for which no Ada predefined primitive is available.
349 -- Check that P (the prefix of the attribute) is not an incomplete
350 -- type or a private type for which no full view has been given.
353 -- Check that P is an object reference
356 -- Validity checking for PolyORB/DSA attribute
359 -- Verify that prefix of attribute N is a program unit
362 -- Verify that prefix of attribute N is fixed or float type
365 -- Verify that prefix of attribute N is a scalar type
368 -- Verify that prefix of attribute N is package Standard. Also checks
369 -- that there are no arguments.
372 -- Validity checking for stream attribute. Nam is the TSS name of the
373 -- corresponding possible defined attribute function (e.g. for the
374 -- Read attribute, Nam will be TSS_Stream_Read).
377 -- Verify that prefix of attribute N is package System
380 -- Verify that prefix of attribute N is a task or task type
383 -- Verify that the prefix of attribute N is a type
386 -- Check that Nod is of the form of a library unit name, i.e that
387 -- it is an identifier, or a selected component whose prefix is
388 -- itself of the form of a library unit name. Note that this is
389 -- quite different from Check_Program_Unit, since it only checks
390 -- the syntactic form of the name, not the semantic identity. This
391 -- is because it is used with attributes (Elab_Body, Elab_Spec,
392 -- UET_Address and Elaborated) which can refer to non-visible unit.
398 -- Posts error using Error_Msg_N at given node, sets type of attribute
399 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
400 -- semantic processing. The message typically contains a % insertion
401 -- character which is replaced by the attribute name. The call with
402 -- no arguments is used when the caller has already generated the
403 -- required error messages.
407 -- Like Error_Attr, but error is posted at the start of the prefix
410 -- Common processing for attributes Definite and Has_Discriminants.
411 -- Checks that prefix is generic indefinite formal type.
414 -- Common processing for attributes Max_Alignment_For_Allocation and
415 -- Max_Size_In_Storage_Elements.
418 -- Common processing for attributes Max and Min
421 -- Used to process attributes whose prefix is package Standard which
422 -- yield values of type Universal_Integer. The attribute reference
423 -- node is rewritten with an integer literal of the given value which
424 -- is marked as static.
427 -- Called when Loop_Entry or Old is used in a potentially unevaluated
428 -- expression. Generates appropriate message or warning depending on
429 -- the setting of Opt.Uneval_Old (or flags in an N_Aspect_Specification
430 -- node in the aspect case).
433 -- Signal unexpected attribute argument (En is the argument)
436 -- Called when processing an attribute that is a function call to a
437 -- non-static function, i.e. an attribute function that either takes
438 -- non-scalar arguments or returns a non-scalar result. Verifies that
439 -- such a call does not appear in a preelaborable context.
441 --------------------
442 -- Address_Checks --
443 --------------------
446 begin
447 -- An Address attribute created by expansion is legal even when it
448 -- applies to other entity-denoting expressions.
453 -- Address attribute on a protected object self reference is legal
458 -- Address applied to an entity
461 declare
464 begin
469 -- An Address attribute is accepted when generated by the
470 -- compiler for dispatching operation, and an error is
471 -- issued once the subprogram is frozen (to avoid confusing
472 -- errors about implicit uses of Address in the dispatch
473 -- table initialization).
477 then
478 Error_Attr_P
482 -- It is illegal to apply 'Address to an intrinsic
483 -- subprogram. This is now formalized in AI05-0095.
484 -- In an instance, an attempt to obtain 'Address of an
485 -- intrinsic subprogram (e.g the renaming of a predefined
486 -- operator that is an actual) raises Program_Error.
494 else
496 Error_Msg_N
500 -- Issue an error if prefix denotes an eliminated subprogram
502 else
506 -- Object or label reference
511 -- Deal with No_Implicit_Aliasing restriction
516 else
521 -- If we have an address of an object, and the attribute
522 -- comes from source, then set the object as potentially
523 -- source modified. We do this because the resulting address
524 -- can potentially be used to modify the variable and we
525 -- might not detect this, leading to some junk warnings.
529 -- Allow Address to be applied to task or protected type,
530 -- returning null address (what is that about???)
536 then
540 -- Anything else is illegal
542 else
547 -- Object is OK
552 -- Subprogram called using dot notation
556 then
559 -- What exactly are we allowing here ??? and is this properly
560 -- documented in the sinfo documentation for this node ???
562 elsif Relaxed_RM_Semantics
564 then
567 -- All other non-entity name cases are illegal
569 else
574 ------------------------------
575 -- Analyze_Access_Attribute --
576 ------------------------------
585 -- Build an access-to-object type whose designated type is DT,
586 -- and whose Ekind is appropriate to the attribute type. The
587 -- type that is constructed is returned as the result.
590 -- Build an access to subprogram whose designated type is the type of
591 -- the prefix. If prefix is overloaded, so is the node itself. The
592 -- result is stored in Acc_Type.
595 -- An access reference whose prefix is a type can legally appear
596 -- within an aggregate, where it is obtained by expansion of
597 -- a defaulted aggregate. The enclosing aggregate that contains
598 -- the self-referenced is flagged so that the self-reference can
599 -- be expanded into a reference to the target object (see exp_aggr).
601 ------------------------------
602 -- Build_Access_Object_Type --
603 ------------------------------
607 New_Internal_Entity
609 begin
617 ----------------------------------
618 -- Build_Access_Subprogram_Type --
619 ----------------------------------
626 -- Deal with possible access to local subprogram. If we have such
627 -- an access, we set a flag to kill all tracked values on any call
628 -- because this access value may be passed around, and any called
629 -- code might use it to access a local procedure which clobbers a
630 -- tracked value. If the scope is a loop or block, indicate that
631 -- value tracking is disabled for the enclosing subprogram.
634 -- Distinguish between access to regular/protected subprograms
636 ------------------------
637 -- Check_Local_Access --
638 ------------------------
641 begin
644 Set_Suppress_Value_Tracking_On_Call
649 --------------
650 -- Get_Kind --
651 --------------
654 begin
657 else
662 -- Start of processing for Build_Access_Subprogram_Type
664 begin
665 -- In the case of an access to subprogram, use the name of the
666 -- subprogram itself as the designated type. Type-checking in
667 -- this case compares the signatures of the designated types.
669 -- Note: This fragment of the tree is temporarily malformed
670 -- because the correct tree requires an E_Subprogram_Type entity
671 -- as the designated type. In most cases this designated type is
672 -- later overridden by the semantics with the type imposed by the
673 -- context during the resolution phase. In the specific case of
674 -- the expression Address!(Prim'Unrestricted_Access), used to
675 -- initialize slots of dispatch tables, this work will be done by
676 -- the expander (see Exp_Aggr).
678 -- The reason to temporarily add this kind of node to the tree
679 -- instead of a proper E_Subprogram_Type itype, is the following:
680 -- in case of errors found in the source file we report better
681 -- error messages. For example, instead of generating the
682 -- following error:
684 -- "expected access to subprogram with profile
685 -- defined at line X"
687 -- we currently generate:
689 -- "expected access to function Z defined at line X"
706 else
725 -- Cannot be applied to intrinsic. Looking at the tests above,
726 -- the only way Etype (N) can still be set to Any_Type is if
727 -- Is_Intrinsic_Subprogram was True for some referenced entity.
734 ----------------------
735 -- OK_Self_Reference --
736 ----------------------
741 begin
744 and then
747 loop
758 -- No enclosing aggregate, or not a self-reference
763 -- Start of processing for Analyze_Access_Attribute
765 begin
766 Check_SPARK_05_Restriction_On_Attribute;
767 Check_E0;
770 Error_Attr_P
774 -- Case of access to subprogram
778 Error_Attr_P
785 -- Issue an error if the prefix denotes an eliminated subprogram
789 -- Check for obsolescent subprogram reference
793 -- Build the appropriate subprogram type
797 -- For P'Access or P'Unrestricted_Access, where P is a nested
798 -- subprogram, we might be passing P to another subprogram (but we
799 -- don't check that here), which might call P. P could modify
800 -- local variables, so we need to kill current values. It is
801 -- important not to do this for library-level subprograms, because
802 -- Kill_Current_Values is very inefficient in the case of library
803 -- level packages with lots of tagged types.
808 -- Do not kill values on nodes initializing dispatch tables
809 -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
810 -- is currently generated by the expander only for this
811 -- purpose. Done to keep the quality of warnings currently
812 -- generated by the compiler (otherwise any declaration of
813 -- a tagged type cleans constant indications from its scope).
817 or else
819 and then Is_Dispatching_Operation
821 then
824 else
825 Kill_Current_Values;
828 -- In the static elaboration model, treat the attribute reference
829 -- as a call for elaboration purposes. Suppress this treatment
830 -- under debug flag. In any case, we are all done.
838 -- Component is an operation of a protected type
842 then
851 -- Deal with incorrect reference to a type, but note that some
852 -- accesses are allowed: references to the current type instance,
853 -- or in Ada 2005 self-referential pointer in a default-initialized
854 -- aggregate.
859 -- The reference may appear in an aggregate that has been expanded
860 -- into a loop. Locate scope of type definition, if any.
869 -- OK if we are within the scope of a limited type
870 -- let's mark the component as having per object constraint
879 declare
882 begin
885 loop
890 Set_Has_Per_Object_Constraint
896 Error_Msg_F
900 -- If a current instance attribute appears in a component
901 -- constraint it must appear alone; other contexts (spec-
902 -- expressions, within a task body) are not subject to this
903 -- restriction.
905 if not In_Spec_Expression
907 and then not
909 N_Index_Or_Discriminant_Constraint)
910 then
911 Error_Msg_N
916 Error_Msg_N
921 -- OK if we are in initialization procedure for the type
922 -- in question, in which case the reference to the type
923 -- is rewritten as a reference to the current object.
928 then
936 -- OK if a task type, this test needs sharpening up ???
941 -- OK if self-reference in an aggregate in Ada 2005, and
942 -- the reference comes from a copied default expression.
944 -- Note that we check legality of self-reference even if the
945 -- expression comes from source, e.g. when a single component
946 -- association in an aggregate has a box association.
949 and then OK_Self_Reference
950 then
953 -- OK if reference to current instance of a protected object
958 -- Otherwise we have an error case
960 else
967 -- If we fall through, we have a normal access to object case
969 -- Unrestricted_Access is (for now) legal wherever an allocator would
970 -- be legal, so its Etype is set to E_Allocator. The expected type
971 -- of the other attributes is a general access type, and therefore
972 -- we label them with E_Access_Attribute_Type.
978 else
979 declare
982 begin
993 -- Special cases when we can find a prefix that is an entity name
995 declare
999 begin
1001 loop
1005 -- If we have an access to an object, and the attribute
1006 -- comes from source, then set the object as potentially
1007 -- source modified. We do this because the resulting access
1008 -- pointer can be used to modify the variable, and we might
1009 -- not detect this, leading to some junk warnings.
1011 -- We only do this for source references, since otherwise
1012 -- we can suppress warnings, e.g. from the unrestricted
1013 -- access generated for validity checks in -gnatVa mode.
1019 -- Mark entity as address taken, and kill current values
1026 N_Indexed_Component)
1027 then
1030 else
1036 -- Check for aliased view.. We allow a nonaliased prefix when within
1037 -- an instance because the prefix may have been a tagged formal
1038 -- object, which is defined to be aliased even when the actual
1039 -- might not be (other instance cases will have been caught in the
1040 -- generic). Similarly, within an inlined body we know that the
1041 -- attribute is legal in the original subprogram, and therefore
1042 -- legal in the expansion.
1045 and then not In_Instance
1046 and then not In_Inlined_Body
1048 then
1049 -- Here we have a non-aliased view. This is illegal unless we
1050 -- have the case of Unrestricted_Access, where for now we allow
1051 -- this (we will reject later if expected type is access to an
1052 -- unconstrained array with a thin pointer).
1054 -- No need for an error message on a generated access reference
1055 -- for the controlling argument in a dispatching call: error will
1056 -- be reported when resolving the call.
1062 -- For Unrestricted_Access, record that prefix is not aliased
1063 -- to simplify legality check later on.
1065 else
1069 -- If we have an aliased view, and we have Unrestricted_Access, then
1070 -- output a warning that Unchecked_Access would have been fine, and
1071 -- change the node to be Unchecked_Access.
1073 else
1074 -- For now, hold off on this change ???
1080 ----------------------------------
1081 -- Analyze_Attribute_Old_Result --
1082 ----------------------------------
1084 procedure Analyze_Attribute_Old_Result
1087 is
1089 -- Verify that the attribute appears within pragma Check that mimics
1090 -- a postcondition.
1093 -- Verify that the attribute appears within a consequence of aspect
1094 -- or pragma Contract_Cases denoted by Prag.
1097 -- Verify that the attribute appears within the "Ensures" argument of
1098 -- aspect or pragma Test_Case denoted by Prag.
1100 function Is_Within
1103 -- Subsidiary to Check_Placemenet_In_XXX. Determine whether arbitrary
1104 -- node Nod is within enclosing node Encl_Nod.
1107 -- Emit a general error when the attributes does not appear in a
1108 -- postcondition-like aspect or pragma.
1110 ------------------------------
1111 -- Check_Placement_In_Check --
1112 ------------------------------
1118 begin
1119 -- The "Name" argument of pragma Check denotes a postcondition
1122 Name_Post_Class,
1123 Name_Postcondition,
1124 Name_Refined_Post)
1125 then
1128 -- Otherwise the placement of the attribute is illegal
1130 else
1131 Placement_Error;
1135 ---------------------------------------
1136 -- Check_Placement_In_Contract_Cases --
1137 ---------------------------------------
1144 begin
1145 -- Obtain the argument of the aspect or pragma
1149 else
1159 -- Detect whether the attribute appears within the
1160 -- consequence of the current contract case.
1164 then
1172 -- Otherwise aspect or pragma Contract_Cases is either malformed
1173 -- or the attribute does not appear within a consequence.
1175 Error_Attr
1177 P);
1180 ----------------------------------
1181 -- Check_Placement_In_Test_Case --
1182 ----------------------------------
1186 Test_Case_Arg
1191 begin
1192 -- Detect whether the attribute appears within the "Ensures"
1193 -- expression of aspect or pragma Test_Case.
1198 else
1199 Error_Attr
1205 ---------------
1206 -- Is_Within --
1207 ---------------
1209 function Is_Within
1212 is
1215 begin
1221 -- Prevent the search from going too far
1233 ---------------------
1234 -- Placement_Error --
1235 ---------------------
1238 begin
1242 -- Specialize the error message for attribute 'Result
1244 else
1245 Error_Attr
1247 P);
1251 -- Local variables
1257 -- Start of processing for Analyze_Attribute_Old_Result
1259 begin
1260 -- Assume that the attribute is illegal
1265 -- Traverse the parent chain to find the aspect or pragma where the
1266 -- attribute resides.
1273 -- Prevent the search from going too far
1282 -- The attribute is allowed to appear only in postcondition-like
1283 -- aspects or pragmas.
1288 else
1298 -- Attribute 'Result is allowed to appear in aspect or pragma
1299 -- [Refined_]Depends (SPARK RM 6.1.5(11)).
1303 then
1307 Name_Post_Class,
1308 Name_Postcondition,
1309 Name_Refined_Post)
1310 then
1316 else
1317 Placement_Error;
1321 -- Otherwise the placement of the attribute is illegal
1323 else
1324 Placement_Error;
1328 -- Find the related subprogram subject to the aspect or pragma
1332 else
1336 -- The aspect or pragma where the attribute resides should be
1337 -- associated with a subprogram declaration or a body. If this is not
1338 -- the case, then the aspect or pragma is illegal. Return as analysis
1339 -- cannot be carried out.
1342 N_Entry_Declaration,
1343 N_Generic_Subprogram_Declaration,
1344 N_Subprogram_Body,
1345 N_Subprogram_Body_Stub,
1346 N_Subprogram_Declaration)
1347 then
1351 -- If we get here, then the attribute is legal
1357 ---------------------------------
1358 -- Bad_Attribute_For_Predicate --
1359 ---------------------------------
1362 begin
1365 then
1367 Bad_Predicated_Subtype_Use
1372 --------------------------------
1373 -- Check_Array_Or_Scalar_Type --
1374 --------------------------------
1380 -- Dimension number for array attributes
1382 begin
1383 -- Case of string literal or string literal subtype. These cases
1384 -- cannot arise from legal Ada code, but the expander is allowed
1385 -- to generate them. They require special handling because string
1386 -- literal subtypes do not have standard bounds (the whole idea
1387 -- of these subtypes is to avoid having to generate the bounds)
1393 -- Scalar types
1396 Check_Type;
1400 else
1405 -- The following is a special test to allow 'First to apply to
1406 -- private scalar types if the attribute comes from generated
1407 -- code. This occurs in the case of Normalize_Scalars code.
1413 then
1416 -- Array types other than string literal subtypes handled above
1418 else
1419 Check_Array_Type;
1421 -- We know prefix is an array type, or the name of an array
1422 -- object, and that the expression, if present, is static
1423 -- and within the range of the dimensions of the type.
1430 -- First dimension assumed
1434 else
1447 ----------------------
1448 -- Check_Array_Type --
1449 ----------------------
1453 -- Dimension number for array attributes
1455 begin
1456 -- If the type is a string literal type, then this must be generated
1457 -- internally, and no further check is required on its legality.
1462 -- If the type is a composite, it is an illegal aggregate, no point
1463 -- in going on.
1469 -- Normal case of array type or subtype
1471 Check_Either_E0_Or_E1;
1472 Check_Dereference;
1478 then
1479 -- Note: we do not call Error_Attr here, since we prefer to
1480 -- continue, using the relevant index type of the array,
1481 -- even though it is unconstrained. This gives better error
1482 -- recovery behavior.
1485 Error_Msg_F
1489 -- The attribute reference freezes the type, and thus the
1490 -- component type, even if the attribute may not depend on the
1491 -- component. Diagnose arrays with incomplete components now.
1492 -- If the prefix is an access to array, this does not freeze
1493 -- the designated type.
1501 else
1509 then
1513 or else
1514 Attr_Id = Attribute_Last
1515 then
1518 else
1529 then
1530 Flag_Non_Static_Expr
1532 Error_Attr;
1536 then
1543 then
1548 -------------------------
1549 -- Check_Asm_Attribute --
1550 -------------------------
1553 begin
1554 Check_Type;
1555 Check_E2;
1557 -- Check first argument is static string expression
1565 Flag_Non_Static_Expr
1567 Error_Attr;
1570 -- Check second argument is right type
1574 -- Note: that is all we need to do, we don't need to check
1575 -- that it appears in a correct context. The Ada type system
1576 -- will do that for us.
1580 ---------------------
1581 -- Check_Component --
1582 ---------------------
1585 begin
1586 Check_E0;
1589 or else
1591 and then
1593 then
1598 ------------------------------------
1599 -- Check_Decimal_Fixed_Point_Type --
1600 ------------------------------------
1603 begin
1604 Check_Type;
1611 -----------------------
1612 -- Check_Dereference --
1613 -----------------------
1616 begin
1618 -- Case of a subtype mark
1624 -- Case of an expression
1630 -- If there is an implicit dereference, then we must freeze the
1631 -- designated type of the access type, since the type of the
1632 -- referenced array is this type (see AI95-00106).
1634 -- As done elsewhere, freezing must not happen when pre-analyzing
1635 -- a pre- or postcondition or a default value for an object or for
1636 -- a formal parameter.
1657 -------------------------
1658 -- Check_Discrete_Type --
1659 -------------------------
1662 begin
1663 Check_Type;
1670 --------------
1671 -- Check_E0 --
1672 --------------
1675 begin
1681 --------------
1682 -- Check_E1 --
1683 --------------
1686 begin
1687 Check_Either_E0_Or_E1;
1691 -- Special-case attributes that are functions and that appear as
1692 -- the prefix of another attribute. Error is posted on parent.
1696 Name_Code_Address,
1697 Name_Access)
1698 then
1705 else
1711 --------------
1712 -- Check_E2 --
1713 --------------
1716 begin
1724 ---------------------------
1725 -- Check_Either_E0_Or_E1 --
1726 ---------------------------
1729 begin
1735 ----------------------
1736 -- Check_Enum_Image --
1737 ----------------------
1742 begin
1743 -- When an enumeration type appears in an attribute reference, all
1744 -- literals of the type are marked as referenced. This must only be
1745 -- done if the attribute reference appears in the current source.
1746 -- Otherwise the information on references may differ between a
1747 -- normal compilation and one that performs inlining.
1751 then
1760 ----------------------------
1761 -- Check_First_Last_Valid --
1762 ----------------------------
1765 begin
1766 Check_Discrete_Type;
1768 -- Freeze the subtype now, so that the following test for predicates
1769 -- works (we set the predicates stuff up at freeze time)
1773 -- Now test for dynamic predicate
1777 then
1778 Error_Attr_P
1782 -- Check non-static subtype
1788 -- Test case for no values
1793 and then
1795 then
1796 Error_Attr_P
1802 ----------------------------
1803 -- Check_Fixed_Point_Type --
1804 ----------------------------
1807 begin
1808 Check_Type;
1815 ------------------------------
1816 -- Check_Fixed_Point_Type_0 --
1817 ------------------------------
1820 begin
1821 Check_Fixed_Point_Type;
1822 Check_E0;
1825 -------------------------------
1826 -- Check_Floating_Point_Type --
1827 -------------------------------
1830 begin
1831 Check_Type;
1838 ---------------------------------
1839 -- Check_Floating_Point_Type_0 --
1840 ---------------------------------
1843 begin
1844 Check_Floating_Point_Type;
1845 Check_E0;
1848 ---------------------------------
1849 -- Check_Floating_Point_Type_1 --
1850 ---------------------------------
1853 begin
1854 Check_Floating_Point_Type;
1855 Check_E1;
1858 ---------------------------------
1859 -- Check_Floating_Point_Type_2 --
1860 ---------------------------------
1863 begin
1864 Check_Floating_Point_Type;
1865 Check_E2;
1868 ------------------------
1869 -- Check_Integer_Type --
1870 ------------------------
1873 begin
1874 Check_Type;
1881 --------------------------------
1882 -- Check_Modular_Integer_Type --
1883 --------------------------------
1886 begin
1887 Check_Type;
1890 Error_Attr_P
1895 ------------------------
1896 -- Check_Not_CPP_Type --
1897 ------------------------
1900 begin
1904 then
1905 Error_Attr_P
1910 -------------------------------
1911 -- Check_Not_Incomplete_Type --
1912 -------------------------------
1918 begin
1919 -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
1920 -- dereference we have to check wrong uses of incomplete types
1921 -- (other wrong uses are checked at their freezing point).
1923 -- In Ada 2012, incomplete types can appear in subprogram
1924 -- profiles, but formals with incomplete types cannot be the
1925 -- prefix of attributes.
1927 -- Example 1: Limited-with
1929 -- limited with Pkg;
1930 -- package P is
1931 -- type Acc is access Pkg.T;
1932 -- X : Acc;
1933 -- S : Integer := X.all'Size; -- ERROR
1934 -- end P;
1936 -- Example 2: Tagged incomplete
1938 -- type T is tagged;
1939 -- type Acc is access all T;
1940 -- X : Acc;
1941 -- S : constant Integer := X.all'Size; -- ERROR
1942 -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
1946 then
1955 Error_Attr_P
1958 -- If the prefix is an access type check the designated type
1962 then
1970 -- A legal use of a shadow entity occurs only when the unit where
1971 -- the non-limited view resides is imported via a regular with
1972 -- clause in the current body. Such references to shadow entities
1973 -- may occur in subprogram formals.
1979 then
1983 -- If still incomplete, it can be a local incomplete type, or a
1984 -- limited view whose scope is also a limited view.
1989 then
1990 Error_Attr_P
1993 -- The limited view may be available indirectly through
1994 -- an intermediate unit. If the non-limited view is available
1995 -- the attribute reference is legal.
1998 and then
2001 then
2002 Error_Attr_P
2007 -- Ada 2012 : formals in bodies may be incomplete, but no attribute
2008 -- legally applies.
2013 then
2014 Error_Attr_P
2020 or else In_Spec_Expression
2021 then
2023 else
2028 ----------------------------
2029 -- Check_Object_Reference --
2030 ----------------------------
2035 begin
2036 -- If we need an object, and we have a prefix that is the name of
2037 -- a function entity, convert it into a function call.
2041 then
2050 -- Otherwise we must have an object reference
2057 ----------------------------
2058 -- Check_PolyORB_Attribute --
2059 ----------------------------
2062 begin
2063 Validate_Non_Static_Attribute_Function_Call;
2065 Check_Type;
2066 Check_Not_CPP_Type;
2069 Error_Attr
2074 ------------------------
2075 -- Check_Program_Unit --
2076 ------------------------
2079 begin
2081 declare
2085 begin
2092 and then
2094 or else
2096 then
2105 ---------------------
2106 -- Check_Real_Type --
2107 ---------------------
2110 begin
2111 Check_Type;
2118 -----------------------
2119 -- Check_Scalar_Type --
2120 -----------------------
2123 begin
2124 Check_Type;
2131 ------------------------------------------
2132 -- Check_SPARK_05_Restriction_On_Attribute --
2133 ------------------------------------------
2136 begin
2141 ---------------------------
2142 -- Check_Standard_Prefix --
2143 ---------------------------
2146 begin
2147 Check_E0;
2154 ----------------------------
2155 -- Check_Stream_Attribute --
2156 ----------------------------
2163 -- True when compiling System.Shared_Storage.Shared_Var_Procs body.
2164 -- For this runtime package (always compiled in GNAT mode), we allow
2165 -- stream attributes references for limited types for the case where
2166 -- shared passive objects are implemented using stream attributes,
2167 -- which is the default in GNAT's persistent storage implementation.
2169 begin
2170 Validate_Non_Static_Attribute_Function_Call;
2172 -- With the exception of 'Input, Stream attributes are procedures,
2173 -- and can only appear at the position of procedure calls. We check
2174 -- for this here, before they are rewritten, to give a more precise
2175 -- diagnostic.
2182 N_Aggregate)
2183 then
2186 else
2187 Error_Attr
2191 Check_Type;
2194 -- Stream attributes not allowed on limited types unless the
2195 -- attribute reference was generated by the expander (in which
2196 -- case the underlying type will be used, as described in Sinfo),
2197 -- or the attribute was specified explicitly for the type itself
2198 -- or one of its ancestors (taking visibility rules into account if
2199 -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
2200 -- (with no visibility restriction).
2202 declare
2204 begin
2206 In_Shared_Var_Procs :=
2208 else
2217 then
2221 Error_Msg_NE
2224 else
2225 Error_Msg_NE
2230 -- Check for no stream operations allowed from No_Tagged_Streams
2234 then
2236 Error_Msg_NE
2241 -- Check restriction violations
2243 -- First check the No_Streams restriction, which prohibits the use
2244 -- of explicit stream attributes in the source program. We do not
2245 -- prevent the occurrence of stream attributes in generated code,
2246 -- for instance those generated implicitly for dispatching purposes.
2252 -- AI05-0057: if restriction No_Default_Stream_Attributes is active,
2253 -- it is illegal to use a predefined elementary type stream attribute
2254 -- either by itself, or more importantly as part of the attribute
2255 -- subprogram for a composite type. However, if the broader
2256 -- restriction No_Streams is active, stream operations are not
2257 -- generated, and there is no error.
2261 then
2262 declare
2265 begin
2267 or else
2268 Nam = TSS_Stream_Read
2269 then
2270 T :=
2272 else
2273 T :=
2280 Error_Msg_NE
2284 Error_Msg_NE
2291 -- Check special case of Exception_Id and Exception_Occurrence which
2292 -- are not allowed for restriction No_Exception_Registration.
2296 or else
2298 then
2302 -- Here we must check that the first argument is an access type
2303 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
2308 -- Note: the double call to Root_Type here is needed because the
2309 -- root type of a class-wide type is the corresponding type (e.g.
2310 -- X for X'Class, and we really want to go to the root.)
2315 then
2316 Error_Attr
2320 -- Check that the second argument is of the right type if there is
2321 -- one (the Input attribute has only one argument so this is skipped)
2328 then
2329 Error_Attr
2336 Check_Not_CPP_Type;
2339 -------------------------
2340 -- Check_System_Prefix --
2341 -------------------------
2344 begin
2350 -----------------------
2351 -- Check_Task_Prefix --
2352 -----------------------
2355 begin
2358 -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
2359 -- task interface class-wide types.
2368 then
2371 else
2373 Error_Attr_P
2377 else
2383 ----------------
2384 -- Check_Type --
2385 ----------------
2387 -- The possibilities are an entity name denoting a type, or an
2388 -- attribute reference that denotes a type (Base or Class). If
2389 -- the type is incomplete, replace it with its full view.
2392 begin
2395 then
2399 Error_Attr_P
2405 then
2411 ---------------------
2412 -- Check_Unit_Name --
2413 ---------------------
2416 begin
2431 ----------------
2432 -- Error_Attr --
2433 ----------------
2436 begin
2443 begin
2446 Error_Attr;
2449 ------------------
2450 -- Error_Attr_P --
2451 ------------------
2454 begin
2457 Error_Attr;
2460 ----------------------------
2461 -- Legal_Formal_Attribute --
2462 ----------------------------
2465 begin
2466 Check_E0;
2470 then
2474 or else In_Instance
2475 or else In_Inlined_Body
2476 then
2481 Error_Attr_P
2485 else
2486 Error_Attr_P
2493 ---------------------------------------------------------------
2494 -- Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements --
2495 ---------------------------------------------------------------
2498 begin
2499 Check_E0;
2500 Check_Type;
2501 Check_Not_Incomplete_Type;
2505 -------------
2506 -- Min_Max --
2507 -------------
2510 begin
2511 Check_E2;
2512 Check_Scalar_Type;
2517 -- Check for comparison on unordered enumeration type
2521 Error_Msg_NE
2527 ------------------------
2528 -- Standard_Attribute --
2529 ------------------------
2532 begin
2533 Check_Standard_Prefix;
2539 --------------------
2540 -- Uneval_Old_Msg --
2541 --------------------
2547 begin
2548 -- If from aspect, then Uneval_Old_Setting comes from flags in the
2549 -- N_Aspect_Specification node that corresponds to the attribute.
2551 -- First find the pragma in which we appear (note that at this stage,
2552 -- even if we appeared originally within an aspect specification, we
2553 -- are now within the corresponding pragma).
2556 loop
2566 else
2570 -- If we did not find the pragma, that's odd, just use the setting
2571 -- from Opt.Uneval_Old. Perhaps this is due to a previous error?
2573 else
2577 -- Processing depends on the setting of Uneval_Old
2581 Error_Attr_P
2587 Error_Msg_F
2599 -------------------------
2600 -- Unexpected Argument --
2601 -------------------------
2604 begin
2608 -------------------------------------------------
2609 -- Validate_Non_Static_Attribute_Function_Call --
2610 -------------------------------------------------
2612 -- This function should be moved to Sem_Dist ???
2615 begin
2616 if In_Preelaborated_Unit
2617 and then not In_Subprogram_Or_Concurrent_Unit
2618 then
2619 Flag_Non_Static_Expr
2624 -- Start of processing for Analyze_Attribute
2626 begin
2627 -- Immediate return if unrecognized attribute (already diagnosed
2628 -- by parser, so there is nothing more that we need to do)
2634 -- Deal with Ada 83 issues
2649 -- Deal with Ada 2005 attributes that are implementation attributes
2650 -- because they appear in a version of Ada before Ada 2005, and
2651 -- similarly for Ada 2012 attributes appearing in an earlier version.
2654 or else
2656 then
2660 -- Remote access to subprogram type access attribute reference needs
2661 -- unanalyzed copy for tree transformation. The analyzed copy is used
2662 -- for its semantic information (whether prefix is a remote subprogram
2663 -- name), the unanalyzed copy is used to construct new subtree rooted
2664 -- with N_Aggregate which represents a fat pointer aggregate.
2670 -- Analyze prefix and exit if error in analysis. If the prefix is an
2671 -- incomplete type, use full view if available. Note that there are
2672 -- some attributes for which we do not analyze the prefix, since the
2673 -- prefix is not a normal name, or else needs special handling.
2680 Aname /= Name_Old
2681 then
2688 then
2696 then
2697 -- Use of current instance within the type. Verify that if the
2698 -- attribute appears within a constraint, it yields an access
2699 -- type, other uses are illegal.
2701 declare
2704 begin
2708 loop
2714 then
2718 then
2719 Error_Msg_N
2735 -- Analyze expressions that may be present, exiting if an error occurs
2741 else
2744 -- Skip analysis for case of Restriction_Set, we do not expect
2745 -- the argument to be analyzed in this case.
2750 -- Check for missing/bad expression (result of previous error)
2772 -- Cases where prefix must be resolvable by itself
2780 then
2781 -- The prefix must be resolvable by itself, without reference to the
2782 -- attribute. One case that requires special handling is a prefix
2783 -- that is a function name, where one interpretation may be a
2784 -- parameterless call. Entry attributes are handled specially below.
2788 then
2794 -- Ada 2005 (AI-345): Since protected and task types have
2795 -- primitive entry wrappers, the attributes Count, and Caller
2796 -- require a context check
2799 declare
2804 begin
2809 else
2818 else
2823 else
2829 -- In SPARK, attributes of private types are only allowed if the full
2830 -- type declaration is visible.
2832 -- Note: the check for Present (Entity (P)) defends against some error
2833 -- conditions where the Entity field is not set.
2839 and then not In_Spec_Expression
2840 then
2844 -- Remaining processing depends on attribute
2848 -- Attributes related to Ada 2012 iterators. Attribute specifications
2849 -- exist for these, but they cannot be queried.
2851 when Attribute_Constant_Indexing |
2852 Attribute_Default_Iterator |
2853 Attribute_Implicit_Dereference |
2854 Attribute_Iterator_Element |
2855 Attribute_Iterable |
2856 Attribute_Variable_Indexing =>
2859 -- Internal attributes used to deal with Ada 2012 delayed aspects. These
2860 -- were already rejected by the parser. Thus they shouldn't appear here.
2865 ------------------
2866 -- Abort_Signal --
2867 ------------------
2870 Check_Standard_Prefix;
2874 ------------
2875 -- Access --
2876 ------------
2879 Analyze_Access_Attribute;
2880 Check_Not_Incomplete_Type;
2882 -------------
2883 -- Address --
2884 -------------
2887 Check_E0;
2888 Address_Checks;
2889 Check_Not_Incomplete_Type;
2892 ------------------
2893 -- Address_Size --
2894 ------------------
2899 --------------
2900 -- Adjacent --
2901 --------------
2904 Check_Floating_Point_Type_2;
2909 ---------
2910 -- Aft --
2911 ---------
2914 Check_Fixed_Point_Type_0;
2917 ---------------
2918 -- Alignment --
2919 ---------------
2923 -- Don't we need more checking here, cf Size ???
2925 Check_E0;
2926 Check_Not_Incomplete_Type;
2927 Check_Not_CPP_Type;
2930 ---------------
2931 -- Asm_Input --
2932 ---------------
2935 Check_Asm_Attribute;
2937 -- The back-end may need to take the address of E2
2945 ----------------
2946 -- Asm_Output --
2947 ----------------
2950 Check_Asm_Attribute;
2957 Error_Attr
2964 -- The back-end may need to take the address of E2
2972 -----------------------------
2973 -- Atomic_Always_Lock_Free --
2974 -----------------------------
2977 Check_E0;
2978 Check_Type;
2981 ----------
2982 -- Base --
2983 ----------
2985 -- Note: when the base attribute appears in the context of a subtype
2986 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
2987 -- the following circuit.
2992 begin
2993 Check_E0;
3000 then
3005 and then Warn_On_Redundant_Constructs
3006 then
3007 Error_Msg_NE -- CODEFIX
3013 Check_SPARK_05_Restriction
3023 ---------
3024 -- Bit --
3025 ---------
3028 begin
3029 Check_E0;
3034 -- What about the access object cases ???
3036 else
3043 ---------------
3044 -- Bit_Order --
3045 ---------------
3048 begin
3049 Check_E0;
3050 Check_Type;
3059 else
3067 -- Reset incorrect indication of staticness
3072 ------------------
3073 -- Bit_Position --
3074 ------------------
3076 -- Note: in generated code, we can have a Bit_Position attribute
3077 -- applied to a (naked) record component (i.e. the prefix is an
3078 -- identifier that references an E_Component or E_Discriminant
3079 -- entity directly, and this is interpreted as expected by Gigi.
3080 -- The following code will not tolerate such usage, but when the
3081 -- expander creates this special case, it marks it as analyzed
3082 -- immediately and sets an appropriate type.
3086 Check_Component;
3091 ------------------
3092 -- Body_Version --
3093 ------------------
3096 Check_E0;
3097 Check_Program_Unit;
3100 --------------
3101 -- Callable --
3102 --------------
3105 Check_E0;
3107 Check_Task_Prefix;
3109 ------------
3110 -- Caller --
3111 ------------
3117 begin
3118 Check_E0;
3127 else
3145 -------------
3146 -- Ceiling --
3147 -------------
3150 Check_Floating_Point_Type_1;
3154 -----------
3155 -- Class --
3156 -----------
3160 Check_E0;
3163 -- Applying Class to untagged incomplete type is obsolescent in Ada
3164 -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
3165 -- this flag gets set by Find_Type in this situation.
3170 then
3171 declare
3173 begin
3176 then
3182 ------------------
3183 -- Code_Address --
3184 ------------------
3187 Check_E0;
3191 then
3196 and then
3198 then
3202 -- Issue an error if the prefix denotes an eliminated subprogram
3204 else
3210 ----------------------
3211 -- Compiler_Version --
3212 ----------------------
3215 Check_E0;
3216 Check_Standard_Prefix;
3221 --------------------
3222 -- Component_Size --
3223 --------------------
3226 Check_E0;
3229 -- Note: unlike other array attributes, unconstrained arrays are OK
3233 else
3234 Check_Array_Type;
3237 -------------
3238 -- Compose --
3239 -------------
3242 Check_Floating_Point_Type_2;
3247 -----------------
3248 -- Constrained --
3249 -----------------
3252 Check_E0;
3255 -- Case from RM J.4(2) of constrained applied to private type
3261 Error_Msg_N
3266 -- If we are within an instance, the attribute must be legal
3267 -- because it was valid in the generic unit. Ditto if this is
3268 -- an inlining of a function declared in an instance.
3273 -- For sure OK if we have a real private type itself, but must
3274 -- be completed, cannot apply Constrained to incomplete type.
3278 -- Note: this is one of the Annex J features that does not
3279 -- generate a warning from -gnatwj, since in fact it seems
3280 -- very useful, and is used in the GNAT runtime.
3282 Check_Not_Incomplete_Type;
3286 -- Normal (non-obsolescent case) of application to object of
3287 -- a discriminated type.
3289 else
3292 -- If N does not come from source, then we allow the
3293 -- the attribute prefix to be of a private type whose
3294 -- full type has discriminants. This occurs in cases
3295 -- involving expanded calls to stream attributes.
3301 -- Must have discriminants or be an access type designating
3302 -- a type with discriminants. If it is a classwide type it
3303 -- has unknown discriminants.
3307 or else
3310 then
3313 -- The rule given in 3.7.2 is part of static semantics, but the
3314 -- intent is clearly that it be treated as a legality rule, and
3315 -- rechecked in the visible part of an instance. Nevertheless
3316 -- the intent also seems to be it should legally apply to the
3317 -- actual of a formal with unknown discriminants, regardless of
3318 -- whether the actual has discriminants, in which case the value
3319 -- of the attribute is determined using the J.4 rules. This choice
3320 -- seems the most useful, and is compatible with existing tests.
3325 -- Also allow an object of a generic type if extensions allowed
3326 -- and allow this for any type at all. (this may be obsolete ???)
3330 and then Extensions_Allowed
3331 then
3336 -- Fall through if bad prefix
3338 Error_Attr_P
3341 ---------------
3342 -- Copy_Sign --
3343 ---------------
3346 Check_Floating_Point_Type_2;
3351 -----------
3352 -- Count --
3353 -----------
3356 declare
3361 begin
3362 Check_E0;
3375 then
3379 E_Entry_Family
3380 then
3381 Error_Attr
3384 else
3389 else
3396 then
3397 Error_Attr
3400 else
3412 -- The prefix denotes either the task type, or else a
3413 -- single task whose task type is being analyzed.
3419 then
3421 else
3422 Error_Attr
3430 and then
3432 then
3437 then
3443 declare
3447 begin
3453 -- Ada 2005 (AI-345): Do not consider primitive entry
3454 -- wrappers generated for task or protected types.
3458 then
3461 else
3473 -----------------------
3474 -- Default_Bit_Order --
3475 -----------------------
3480 begin
3481 Check_Standard_Prefix;
3485 else
3497 ----------------------------------
3498 -- Default_Scalar_Storage_Order --
3499 ----------------------------------
3504 begin
3505 Check_Standard_Prefix;
3511 else
3528 --------------
3529 -- Definite --
3530 --------------
3533 Legal_Formal_Attribute;
3535 -----------
3536 -- Delta --
3537 -----------
3540 Check_Fixed_Point_Type_0;
3543 ------------
3544 -- Denorm --
3545 ------------
3548 Check_Floating_Point_Type_0;
3551 -----------
3552 -- Deref --
3553 -----------
3556 Check_Type;
3557 Check_E1;
3561 ---------------------
3562 -- Descriptor_Size --
3563 ---------------------
3566 Check_E0;
3574 ------------
3575 -- Digits --
3576 ------------
3579 Check_E0;
3580 Check_Type;
3584 then
3585 Error_Attr_P
3591 ---------------
3592 -- Elab_Body --
3593 ---------------
3595 -- Also handles processing for Elab_Spec and Elab_Subp_Body
3597 when Attribute_Elab_Body |
3598 Attribute_Elab_Spec |
3599 Attribute_Elab_Subp_Body =>
3601 Check_E0;
3605 -- We have to manually call the expander in this case to get
3606 -- the necessary expansion (normally attributes that return
3607 -- entities are not expanded).
3611 ---------------
3612 -- Elab_Spec --
3613 ---------------
3615 -- Shares processing with Elab_Body
3617 ----------------
3618 -- Elaborated --
3619 ----------------
3622 Check_E0;
3626 ----------
3627 -- Emax --
3628 ----------
3631 Check_Floating_Point_Type_0;
3634 -------------
3635 -- Enabled --
3636 -------------
3639 Check_Either_E0_Or_E1;
3656 --------------
3657 -- Enum_Rep --
3658 --------------
3661 begin
3663 Check_E1;
3664 Check_Discrete_Type;
3667 else
3671 then
3672 Error_Attr_P
3681 --------------
3682 -- Enum_Val --
3683 --------------
3686 Check_E1;
3687 Check_Type;
3693 -- If the enumeration type has a standard representation, the effect
3694 -- is the same as 'Val, so rewrite the attribute as a 'Val.
3704 -- Non-standard representation case (enumeration with holes)
3706 else
3707 Check_Enum_Image;
3713 -------------
3714 -- Epsilon --
3715 -------------
3718 Check_Floating_Point_Type_0;
3721 --------------
3722 -- Exponent --
3723 --------------
3726 Check_Floating_Point_Type_1;
3730 ------------------
3731 -- External_Tag --
3732 ------------------
3735 Check_E0;
3736 Check_Type;
3744 ---------------
3745 -- Fast_Math --
3746 ---------------
3749 Check_Standard_Prefix;
3752 -----------
3753 -- First --
3754 -----------
3757 Check_Array_Or_Scalar_Type;
3758 Bad_Attribute_For_Predicate;
3760 ---------------
3761 -- First_Bit --
3762 ---------------
3765 Check_Component;
3768 -----------------
3769 -- First_Valid --
3770 -----------------
3773 Check_First_Last_Valid;
3776 -----------------
3777 -- Fixed_Value --
3778 -----------------
3781 Check_E1;
3782 Check_Fixed_Point_Type;
3786 -----------
3787 -- Floor --
3788 -----------
3791 Check_Floating_Point_Type_1;
3795 ----------
3796 -- Fore --
3797 ----------
3800 Check_Fixed_Point_Type_0;
3803 --------------
3804 -- Fraction --
3805 --------------
3808 Check_Floating_Point_Type_1;
3812 --------------
3813 -- From_Any --
3814 --------------
3817 Check_E1;
3818 Check_PolyORB_Attribute;
3821 -----------------------
3822 -- Has_Access_Values --
3823 -----------------------
3826 Check_Type;
3827 Check_E0;
3830 ----------------------
3831 -- Has_Same_Storage --
3832 ----------------------
3835 Check_E1;
3837 -- The arguments must be objects of any type
3845 -----------------------
3846 -- Has_Tagged_Values --
3847 -----------------------
3850 Check_Type;
3851 Check_E0;
3854 -----------------------
3855 -- Has_Discriminants --
3856 -----------------------
3859 Legal_Formal_Attribute;
3861 --------------
3862 -- Identity --
3863 --------------
3866 Check_E0;
3872 -- Ada 2005 (AI-345): Attribute 'Identity may be applied to task
3873 -- interface class-wide types.
3882 then
3886 else
3888 Error_Attr_P
3891 else
3892 Error_Attr_P
3897 -----------
3898 -- Image --
3899 -----------
3902 begin
3903 Check_SPARK_05_Restriction_On_Attribute;
3904 Check_Scalar_Type;
3910 Error_Msg_N
3919 Check_E1;
3921 Check_Enum_Image;
3922 Validate_Non_Static_Attribute_Function_Call;
3924 -- Check restriction No_Fixed_IO. Note the check of Comes_From_Source
3925 -- to avoid giving a duplicate message for Img expanded into Image.
3930 then
3935 ---------
3936 -- Img --
3937 ---------
3940 begin
3941 Check_E0;
3946 then
3947 Error_Attr_P
3951 Check_Enum_Image;
3953 -- Check restriction No_Fixed_IO
3957 then
3962 -----------
3963 -- Input --
3964 -----------
3967 Check_E1;
3971 -------------------
3972 -- Integer_Value --
3973 -------------------
3976 Check_E1;
3977 Check_Integer_Type;
3980 -- Signal an error if argument type is not a specific fixed-point
3981 -- subtype. An error has been signalled already if the argument
3982 -- was not of a fixed-point type.
3990 -------------------
3991 -- Invalid_Value --
3992 -------------------
3995 Check_E0;
3996 Check_Scalar_Type;
4000 -----------
4001 -- Large --
4002 -----------
4005 Check_E0;
4006 Check_Real_Type;
4009 ----------
4010 -- Last --
4011 ----------
4014 Check_Array_Or_Scalar_Type;
4015 Bad_Attribute_For_Predicate;
4017 --------------
4018 -- Last_Bit --
4019 --------------
4022 Check_Component;
4025 ----------------
4026 -- Last_Valid --
4027 ----------------
4030 Check_First_Last_Valid;
4033 ------------------
4034 -- Leading_Part --
4035 ------------------
4038 Check_Floating_Point_Type_2;
4043 ------------
4044 -- Length --
4045 ------------
4048 Check_Array_Type;
4051 -------------------
4052 -- Library_Level --
4053 -------------------
4056 Check_E0;
4069 ---------------
4070 -- Lock_Free --
4071 ---------------
4074 Check_E0;
4078 Error_Attr_P
4082 ----------------
4083 -- Loop_Entry --
4084 ----------------
4088 -- Inspect the prefix for any uses of entities declared within the
4089 -- related loop. Loop_Id denotes the loop identifier.
4091 --------------------------------
4092 -- Check_References_In_Prefix --
4093 --------------------------------
4099 -- Determine whether a reference mentions an entity declared
4100 -- within the related loop.
4103 -- Determine whether Nod appears in the subtree of Loop_Decl
4105 ---------------------
4106 -- Check_Reference --
4107 ---------------------
4110 begin
4114 then
4115 Error_Attr
4117 Nod);
4119 else
4126 ---------------------
4127 -- Declared_Within --
4128 ---------------------
4133 begin
4139 -- Prevent the search from going too far
4151 -- Start of processing for Check_Prefix_For_Local_References
4153 begin
4157 -- Local variables
4167 -- Start of processing for Loop_Entry
4169 begin
4172 -- Set the type of the attribute now to ensure the successfull
4173 -- continuation of analysis even if the attribute is misplaced.
4177 -- Attribute 'Loop_Entry may appear in several flavors:
4179 -- * Prefix'Loop_Entry - in this form, the attribute applies to the
4180 -- nearest enclosing loop.
4182 -- * Prefix'Loop_Entry (Expr) - depending on what Expr denotes, the
4183 -- attribute may be related to a loop denoted by label Expr or
4184 -- the prefix may denote an array object and Expr may act as an
4185 -- indexed component.
4187 -- * Prefix'Loop_Entry (Expr1, ..., ExprN) - the attribute applies
4188 -- to the nearest enclosing loop, all expressions are part of
4189 -- an indexed component.
4191 -- * Prefix'Loop_Entry (Expr) (...) (...) - depending on what Expr
4192 -- denotes, the attribute may be related to a loop denoted by
4193 -- label Expr or the prefix may denote a multidimensional array
4194 -- array object and Expr along with the rest of the expressions
4195 -- may act as indexed components.
4197 -- Regardless of variations, the attribute reference does not have an
4198 -- expression list. Instead, all available expressions are stored as
4199 -- indexed components.
4201 -- When the attribute is part of an indexed component, find the first
4202 -- expression as it will determine the semantics of 'Loop_Entry.
4208 -- The attribute reference appears in the following form:
4210 -- Prefix'Loop_Entry (Exp1, Expr2, ..., ExprN) [(...)]
4212 -- In this case, the loop name is omitted and no rewriting is
4213 -- required.
4218 -- The form of the attribute is:
4220 -- Prefix'Loop_Entry (Expr) [(...)]
4222 -- If Expr denotes a loop entry, the whole attribute and indexed
4223 -- component will have to be rewritten to reflect this relation.
4225 else
4228 -- Do not expand the expression as it may have side effects.
4229 -- Simply preanalyze to determine whether it is a loop name or
4230 -- something else.
4237 then
4240 -- Transform the attribute and enclosing indexed component
4251 -- The prefix must denote an object
4257 -- The prefix cannot be of a limited type because the expansion of
4258 -- Loop_Entry must create a constant initialized by the evaluated
4259 -- prefix.
4265 -- Climb the parent chain to verify the location of the attribute and
4266 -- find the enclosing loop.
4271 -- Locate the corresponding enclosing pragma. Note that in the
4272 -- case of Assert[And_Cut] and Assume, we have already checked
4273 -- that the pragma appears in an appropriate loop location.
4277 Name_Loop_Invariant,
4278 Name_Loop_Variant,
4279 Name_Assert,
4280 Name_Assert_And_Cut,
4281 Name_Assume)
4282 then
4285 -- Locate the enclosing loop (if any). Note that Ada 2012 array
4286 -- iteration may be expanded into several nested loops, we are
4287 -- interested in the outermost one which has the loop identifier.
4291 then
4294 -- The original attribute reference may lack a loop name. Use
4295 -- the name of the enclosing loop because it is the related
4296 -- loop.
4304 -- Prevent the search from going too far
4313 -- Loop_Entry must appear within a Loop_Assertion pragma (Assert,
4314 -- Assert_And_Cut, Assume count as loop assertion pragmas for this
4315 -- purpose if they appear in an appropriate location in a loop,
4316 -- which was already checked by the top level pragma circuit).
4322 -- A Loop_Entry that applies to a given loop statement must not
4323 -- appear within a body of accept statement, if this construct is
4324 -- itself enclosed by the given loop statement.
4333 else
4334 Error_Attr
4340 -- The prefix cannot mention entities declared within the related
4341 -- loop because they will not be visible once the prefix is moved
4342 -- outside the loop.
4346 -- The prefix must denote a static entity if the pragma does not
4347 -- apply to the innermost enclosing loop statement, or if it appears
4348 -- within a potentially unevaluated epxression.
4352 then
4357 then
4358 Error_Attr_P
4363 Uneval_Old_Msg;
4366 -- Replace the Loop_Entry attribute reference by its prefix if the
4367 -- related pragma is ignored. This transformation is OK with respect
4368 -- to typing because Loop_Entry's type is that of its prefix. This
4369 -- early transformation also avoids the generation of a useless loop
4370 -- entry constant.
4379 -------------
4380 -- Machine --
4381 -------------
4384 Check_Floating_Point_Type_1;
4388 ------------------
4389 -- Machine_Emax --
4390 ------------------
4393 Check_Floating_Point_Type_0;
4396 ------------------
4397 -- Machine_Emin --
4398 ------------------
4401 Check_Floating_Point_Type_0;
4404 ----------------------
4405 -- Machine_Mantissa --
4406 ----------------------
4409 Check_Floating_Point_Type_0;
4412 -----------------------
4413 -- Machine_Overflows --
4414 -----------------------
4417 Check_Real_Type;
4418 Check_E0;
4421 -------------------
4422 -- Machine_Radix --
4423 -------------------
4426 Check_Real_Type;
4427 Check_E0;
4430 ----------------------
4431 -- Machine_Rounding --
4432 ----------------------
4435 Check_Floating_Point_Type_1;
4439 --------------------
4440 -- Machine_Rounds --
4441 --------------------
4444 Check_Real_Type;
4445 Check_E0;
4448 ------------------
4449 -- Machine_Size --
4450 ------------------
4453 Check_E0;
4454 Check_Type;
4455 Check_Not_Incomplete_Type;
4458 --------------
4459 -- Mantissa --
4460 --------------
4463 Check_E0;
4464 Check_Real_Type;
4467 ---------
4468 -- Max --
4469 ---------
4472 Min_Max;
4474 ----------------------------------
4475 -- Max_Alignment_For_Allocation --
4476 ----------------------------------
4479 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4481 ----------------------------------
4482 -- Max_Size_In_Storage_Elements --
4483 ----------------------------------
4486 Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
4488 -----------------------
4489 -- Maximum_Alignment --
4490 -----------------------
4495 --------------------
4496 -- Mechanism_Code --
4497 --------------------
4502 then
4506 Check_Either_E0_Or_E1;
4513 Flag_Non_Static_Expr
4515 Error_Attr;
4519 then
4526 ---------
4527 -- Min --
4528 ---------
4531 Min_Max;
4533 ---------
4534 -- Mod --
4535 ---------
4539 -- Note: this attribute is only allowed in Ada 2005 mode, but
4540 -- we do not need to test that here, since Mod is only recognized
4541 -- as an attribute name in Ada 2005 mode during the parse.
4543 Check_E1;
4544 Check_Modular_Integer_Type;
4548 -----------
4549 -- Model --
4550 -----------
4553 Check_Floating_Point_Type_1;
4557 ----------------
4558 -- Model_Emin --
4559 ----------------
4562 Check_Floating_Point_Type_0;
4565 -------------------
4566 -- Model_Epsilon --
4567 -------------------
4570 Check_Floating_Point_Type_0;
4573 --------------------
4574 -- Model_Mantissa --
4575 --------------------
4578 Check_Floating_Point_Type_0;
4581 -----------------
4582 -- Model_Small --
4583 -----------------
4586 Check_Floating_Point_Type_0;
4589 -------------
4590 -- Modulus --
4591 -------------
4594 Check_E0;
4595 Check_Modular_Integer_Type;
4598 --------------------
4599 -- Null_Parameter --
4600 --------------------
4607 -- Used if bad Null parameter attribute node is found. Issues
4608 -- given error message, and also sets the type to Any_Type to
4609 -- avoid blowups later on from dealing with a junk node.
4612 -- Called to check that Proc_Ent is imported subprogram
4614 ------------------------
4615 -- Bad_Null_Parameter --
4616 ------------------------
4619 begin
4624 ----------------------
4625 -- Must_Be_Imported --
4626 ----------------------
4631 begin
4632 -- Ignore check if procedure not frozen yet (we will get
4633 -- another chance when the default parameter is reanalyzed)
4639 Bad_Null_Parameter
4642 else
4647 -- Start of processing for Null_Parameter
4649 begin
4650 Check_Type;
4651 Check_E0;
4654 -- Case of attribute used as default expression
4659 -- Case of attribute used as actual for subprogram (positional)
4663 then
4666 -- Case of attribute used as actual for subprogram (named)
4671 then
4674 -- Not an allowed case
4676 else
4677 Bad_Null_Parameter
4682 -----------------
4683 -- Object_Size --
4684 -----------------
4687 Check_E0;
4688 Check_Type;
4689 Check_Not_Incomplete_Type;
4692 ---------
4693 -- Old --
4694 ---------
4698 -- Inspect the contents of the prefix and detect illegal uses of a
4699 -- nested 'Old, attribute 'Result or a use of an entity declared in
4700 -- the related postcondition expression. Subp_Id is the subprogram to
4701 -- which the related postcondition applies.
4703 --------------------------------
4704 -- Check_References_In_Prefix --
4705 --------------------------------
4709 -- Detect attribute 'Old, attribute 'Result of a use of an entity
4710 -- and perform the appropriate semantic check.
4712 ---------------------
4713 -- Check_Reference --
4714 ---------------------
4717 begin
4718 -- Attributes 'Old and 'Result cannot appear in the prefix of
4719 -- another attribute 'Old.
4723 Name_Result)
4724 then
4727 Error_Msg_N
4729 Nod);
4732 -- Entities mentioned within the prefix of attribute 'Old must
4733 -- be global to the related postcondition. If this is not the
4734 -- case, then the scope of the local entity is nested within
4735 -- that of the subprogram.
4740 then
4741 Error_Attr
4743 Nod);
4746 -- Otherwise keep inspecting the prefix
4748 else
4755 -- Start of processing for Check_References_In_Prefix
4757 begin
4761 -- Local variables
4768 -- Start of processing for Old
4770 begin
4771 -- The attribute reference is a primary. If any expressions follow,
4772 -- then the attribute reference is an indexable object. Transform the
4773 -- attribute into an indexed component and analyze it.
4778 Prefix =>
4789 -- The aspect or pragma where attribute 'Old resides should be
4790 -- associated with a subprogram declaration or a body. If this is not
4791 -- the case, then the aspect or pragma is illegal. Return as analysis
4792 -- cannot be carried out.
4798 -- The prefix must be preanalyzed as the full analysis will take
4799 -- place during expansion.
4803 -- Ensure that the prefix does not contain attributes 'Old or 'Result
4807 -- Set the type of the attribute now to prevent cascaded errors
4812 -- Legality checks
4818 -- The prefix is a simple name
4823 -- Emit a warning when the prefix is a constant. Note that the use
4824 -- of Error_Attr would reset the type of N to Any_Type even though
4825 -- this is a warning. Use Error_Msg_XXX instead.
4829 Error_Msg_N
4833 -- Otherwise the prefix is not a simple name
4835 else
4836 -- Ensure that the prefix of attribute 'Old is an entity when it
4837 -- is potentially unevaluated (6.1.1 (27/3)).
4840 Uneval_Old_Msg;
4842 -- Detect a possible infinite recursion when the prefix denotes
4843 -- the related function.
4845 -- function Func (...) return ...
4846 -- with Post => Func'Old ...;
4853 then
4860 -- The prefix of attribute 'Old may refer to a component of a
4861 -- formal parameter. In this case its expansion may generate
4862 -- actual subtypes that are referenced in an inner context and
4863 -- that must be elaborated within the subprogram itself. If the
4864 -- prefix includes a function call, it may involve finalization
4865 -- actions that should be inserted when the attribute has been
4866 -- rewritten as a declaration. Create a declaration for the prefix
4867 -- and insert it at the start of the enclosing subprogram. This is
4868 -- an expansion activity that has to be performed now to prevent
4869 -- out-of-order issues.
4871 -- This expansion is both harmful and not needed in SPARK mode,
4872 -- since the formal verification backend relies on the types of
4873 -- nodes (hence is not robust w.r.t. a change to base type here),
4874 -- and does not suffer from the out-of-order issue described
4875 -- above. Thus, this expansion is skipped in SPARK mode.
4888 ----------------------
4889 -- Overlaps_Storage --
4890 ----------------------
4893 Check_E1;
4895 -- Both arguments must be objects of any type
4903 ------------
4904 -- Output --
4905 ------------
4908 Check_E2;
4913 ------------------
4914 -- Partition_ID --
4915 ------------------
4918 begin
4919 Check_E0;
4923 Error_Attr_P
4926 -- The defining entity of prefix should not be declared inside a
4927 -- Pure unit. RM E.1(8). Is_Pure was set during declaration.
4931 then
4939 -------------------------
4940 -- Passed_By_Reference --
4941 -------------------------
4944 Check_E0;
4945 Check_Type;
4948 ------------------
4949 -- Pool_Address --
4950 ------------------
4953 Check_E0;
4956 ---------
4957 -- Pos --
4958 ---------
4961 Check_Discrete_Type;
4962 Check_E1;
4967 Check_SPARK_05_Restriction
4974 --------------
4975 -- Position --
4976 --------------
4979 Check_Component;
4982 ----------
4983 -- Pred --
4984 ----------
4987 Check_Scalar_Type;
4988 Check_E1;
4993 Check_SPARK_05_Restriction
5000 -- Since Pred works on the base type, we normally do no check for the
5001 -- floating-point case, since the base type is unconstrained. But we
5002 -- make an exception in Check_Float_Overflow mode.
5009 -- If not modular type, test for overflow check required
5011 else
5014 then
5019 --------------
5020 -- Priority --
5021 --------------
5023 -- Ada 2005 (AI-327): Dynamic ceiling priorities
5030 Check_E0;
5032 -- The prefix must be a protected object (AARM D.5.2 (2/2))
5039 then
5041 else
5047 -- Must be called from within a protected procedure or entry of the
5048 -- protected object.
5050 declare
5053 begin
5057 loop
5067 Validate_Non_Static_Attribute_Function_Call;
5069 -----------
5070 -- Range --
5071 -----------
5074 Check_Array_Or_Scalar_Type;
5075 Bad_Attribute_For_Predicate;
5080 then
5081 Error_Attr
5085 ------------
5086 -- Result --
5087 ------------
5090 function Denote_Same_Function
5093 -- Determine whether the entity of the prefix Pref_Id denotes the
5094 -- same entity as that of the related subprogram Spec_Id.
5096 --------------------------
5097 -- Denote_Same_Function --
5098 --------------------------
5100 function Denote_Same_Function
5103 is
5106 begin
5107 -- The prefix denotes the related subprogram
5112 -- Account for a special case when attribute 'Result appears in
5113 -- the postcondition of a generic function.
5115 -- generic
5116 -- function Gen_Func return ...
5117 -- with Post => Gen_Func'Result ...;
5119 -- When the generic function is instantiated, the Chars field of
5120 -- the instantiated prefix still denotes the name of the generic
5121 -- function. Note that any preemptive transformation is impossible
5122 -- without a proper analysis. The structure of the wrapper package
5123 -- is as follows:
5125 -- package Anon_Gen_Pack is
5126 -- <subtypes and renamings>
5127 -- function Subp_Decl return ...; -- (!)
5128 -- pragma Postcondition (Gen_Func'Result ...); -- (!)
5129 -- function Gen_Func ... renames Subp_Decl;
5130 -- end Anon_Gen_Pack;
5135 then
5141 then
5146 -- Otherwise the prefix does not denote the related subprogram
5151 -- Local variables
5157 -- Start of processing for Result
5159 begin
5160 -- The attribute reference is a primary. If any expressions follow,
5161 -- then the attribute reference is an indexable object. Transform the
5162 -- attribute into an indexed component and analyze it.
5167 Prefix =>
5178 -- The aspect or pragma where attribute 'Result resides should be
5179 -- associated with a subprogram declaration or a body. If this is not
5180 -- the case, then the aspect or pragma is illegal. Return as analysis
5181 -- cannot be carried out.
5187 -- Attribute 'Result is part of a _Postconditions procedure. There is
5188 -- no need to perform the semantic checks below as they were already
5189 -- verified when the attribute was analyzed in its original context.
5190 -- Instead, rewrite the attribute as a reference to formal parameter
5191 -- _Result of the _Postconditions procedure.
5196 -- The type of formal parameter _Result is that of the function
5197 -- encapsulating the _Postconditions procedure. Resolution must
5198 -- be carried out against the function return type.
5202 -- Otherwise attribute 'Result appears in its original context and
5203 -- all semantic checks should be carried out.
5205 else
5206 -- Verify the legality of the prefix. It must denotes the entity
5207 -- of the related [generic] function.
5215 -- Correct the prefix of the attribute when the context
5216 -- is a generic function.
5225 -- Otherwise the prefix denotes some unrelated function
5227 else
5229 Error_Attr
5233 -- Otherwise the prefix denotes some other form of subprogram
5234 -- entity.
5236 else
5237 Error_Attr
5242 -- Otherwise the prefix is illegal
5244 else
5251 ------------------
5252 -- Range_Length --
5253 ------------------
5256 Check_E0;
5257 Check_Discrete_Type;
5260 ----------
5261 -- Read --
5262 ----------
5265 Check_E2;
5271 ---------
5272 -- Ref --
5273 ---------
5276 Check_E1;
5281 then
5288 ---------------
5289 -- Remainder --
5290 ---------------
5293 Check_Floating_Point_Type_2;
5298 ---------------------
5299 -- Restriction_Set --
5300 ---------------------
5307 begin
5308 Check_E1;
5310 Check_System_Prefix;
5312 -- No_Dependence case
5320 Error_Attr;
5323 -- See if there is an entry already in the table. That's the
5324 -- case in which we can return True.
5329 then
5335 -- If not in the No_Dependence table, result is False
5339 -- In this case, we must ensure that the binder will reject any
5340 -- other unit in the partition that sets No_Dependence for this
5341 -- unit. We do that by making an entry in the special table kept
5342 -- for this purpose (if the entry is not there already).
5347 Restriction_Set_Dependences.Last
5348 loop
5356 -- Normal restriction case
5358 else
5363 else
5374 Error_Attr
5380 else
5388 -----------
5389 -- Round --
5390 -----------
5393 Check_E1;
5394 Check_Decimal_Fixed_Point_Type;
5397 -- Because the context is universal_real (3.5.10(12)) it is a
5398 -- legal context for a universal fixed expression. This is the
5399 -- only attribute whose functional description involves U_R.
5402 declare
5407 begin
5415 --------------
5416 -- Rounding --
5417 --------------
5420 Check_Floating_Point_Type_1;
5424 ---------------
5425 -- Safe_Emax --
5426 ---------------
5429 Check_Floating_Point_Type_0;
5432 ----------------
5433 -- Safe_First --
5434 ----------------
5437 Check_Floating_Point_Type_0;
5440 ----------------
5441 -- Safe_Large --
5442 ----------------
5445 Check_E0;
5446 Check_Real_Type;
5449 ---------------
5450 -- Safe_Last --
5451 ---------------
5454 Check_Floating_Point_Type_0;
5457 ----------------
5458 -- Safe_Small --
5459 ----------------
5462 Check_E0;
5463 Check_Real_Type;
5466 --------------------------
5467 -- Scalar_Storage_Order --
5468 --------------------------
5471 declare
5474 begin
5475 Check_E0;
5476 Check_Type;
5480 -- In GNAT mode, the attribute applies to generic types as well
5481 -- as composite types, and for non-composite types always returns
5482 -- the default bit order for the target.
5485 and then not In_Instance
5486 then
5487 Error_Attr_P
5493 else
5501 else
5512 -- Reset incorrect indication of staticness
5517 -----------
5518 -- Scale --
5519 -----------
5522 Check_E0;
5523 Check_Decimal_Fixed_Point_Type;
5526 -------------
5527 -- Scaling --
5528 -------------
5531 Check_Floating_Point_Type_2;
5535 ------------------
5536 -- Signed_Zeros --
5537 ------------------
5540 Check_Floating_Point_Type_0;
5543 ----------
5544 -- Size --
5545 ----------
5548 begin
5549 Check_E0;
5551 -- If prefix is parameterless function call, rewrite and resolve
5552 -- as such.
5556 then
5559 -- Similar processing for a protected function call
5563 then
5573 then
5578 then
5581 -- Some other compilers allow dubious use of X'???'Size
5583 elsif Relaxed_RM_Semantics
5585 then
5588 else
5592 Check_Not_Incomplete_Type;
5593 Check_Not_CPP_Type;
5597 -----------
5598 -- Small --
5599 -----------
5602 Check_E0;
5603 Check_Real_Type;
5606 ------------------
5607 -- Storage_Pool --
5608 ------------------
5610 when Attribute_Storage_Pool |
5612 begin
5613 Check_E0;
5617 Error_Attr_P
5621 -- Set appropriate entity
5625 else
5631 Name_Simple_Storage_Pool_Type))
5632 then
5639 Rewrite
5646 -- In the Simple_Storage_Pool case, verify that the pool entity is
5647 -- actually of a simple storage pool type, and set the attribute's
5648 -- type to the pool object's type.
5650 else
5652 Name_Simple_Storage_Pool_Type))
5653 then
5654 Error_Attr_P
5662 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5663 -- Storage_Pool since this attribute is not defined for such
5664 -- types (RM E.2.3(22)).
5668 else
5673 ------------------
5674 -- Storage_Size --
5675 ------------------
5678 begin
5679 Check_E0;
5684 -- Use with tasks is an obsolescent feature
5690 Error_Attr_P
5696 then
5697 Check_Type;
5700 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
5701 -- Storage_Size since this attribute is not defined for
5702 -- such types (RM E.2.3(22)).
5706 -- The prefix is allowed to be an implicit dereference of an
5707 -- access value designating a task.
5709 else
5710 Check_Task_Prefix;
5714 else
5719 ------------------
5720 -- Storage_Unit --
5721 ------------------
5726 -----------------
5727 -- Stream_Size --
5728 -----------------
5731 Check_E0;
5732 Check_Type;
5736 then
5738 else
5742 ---------------
5743 -- Stub_Type --
5744 ---------------
5747 Check_Type;
5748 Check_E0;
5752 -- For a real RACW [sub]type, use corresponding stub type
5756 New_Occurrence_Of
5759 -- For a generic type (that has been marked as an RACW using the
5760 -- Remote_Access_Type aspect or pragma), use a generic RACW stub
5761 -- type. Note that if the actual is not a remote access type, the
5762 -- instantiation will fail.
5764 else
5765 -- Note: we go to the underlying type here because the view
5766 -- returned by RTE (RE_RACW_Stub_Type) might be incomplete.
5769 New_Occurrence_Of
5773 else
5774 Error_Attr_P
5778 ----------
5779 -- Succ --
5780 ----------
5783 Check_Scalar_Type;
5784 Check_E1;
5789 Check_SPARK_05_Restriction
5796 -- Since Pred works on the base type, we normally do no check for the
5797 -- floating-point case, since the base type is unconstrained. But we
5798 -- make an exception in Check_Float_Overflow mode.
5805 -- If not modular type, test for overflow check required
5807 else
5810 then
5815 --------------------------------
5816 -- System_Allocator_Alignment --
5817 --------------------------------
5822 ---------
5823 -- Tag --
5824 ---------
5827 begin
5828 Check_E0;
5829 Check_Dereference;
5834 -- Next test does not apply to generated code why not, and what does
5835 -- the illegal reference mean???
5840 then
5841 Error_Attr_P
5846 -- The prefix cannot be an incomplete type. However, references to
5847 -- 'Tag can be generated when expanding interface conversions, and
5848 -- this is legal.
5851 Check_Not_Incomplete_Type;
5854 -- Set appropriate type
5859 -----------------
5860 -- Target_Name --
5861 -----------------
5867 begin
5868 Check_Standard_Prefix;
5883 ----------------
5884 -- Terminated --
5885 ----------------
5888 Check_E0;
5890 Check_Task_Prefix;
5892 ----------------
5893 -- To_Address --
5894 ----------------
5899 begin
5900 Check_E1;
5902 Check_System_Prefix;
5912 -- OK static expression case, check range and set appropriate type
5918 or else
5920 then
5924 -- In most cases the expression is a numeric literal or some other
5925 -- address expression, but if it is a declared constant it may be
5926 -- of a compatible type that must be left on the node.
5931 -- Set type to universal integer if negative
5936 -- Otherwise set type to Unsigned_64 to accomodate max values
5938 else
5946 ------------
5947 -- To_Any --
5948 ------------
5951 Check_E1;
5952 Check_PolyORB_Attribute;
5955 ----------------
5956 -- Truncation --
5957 ----------------
5960 Check_Floating_Point_Type_1;
5964 ----------------
5965 -- Type_Class --
5966 ----------------
5969 Check_E0;
5970 Check_Type;
5971 Check_Not_Incomplete_Type;
5974 --------------
5975 -- TypeCode --
5976 --------------
5979 Check_E0;
5980 Check_PolyORB_Attribute;
5983 --------------
5984 -- Type_Key --
5985 --------------
5988 Check_E0;
5989 Check_Type;
5991 -- This processing belongs in Eval_Attribute ???
5993 declare
5995 -- A very preliminary implementation. For now, a signature
5996 -- consists of only the type name. This is clearly incomplete
5997 -- (e.g., adding a new field to a record type should change the
5998 -- type's Type_Key attribute).
6000 --------------
6001 -- Type_Key --
6002 --------------
6008 begin
6009 -- Copy all characters in Full_Name but the trailing NUL
6011 Start_String;
6020 begin
6026 -----------------
6027 -- UET_Address --
6028 -----------------
6031 Check_E0;
6035 -----------------------
6036 -- Unbiased_Rounding --
6037 -----------------------
6040 Check_Floating_Point_Type_1;
6044 ----------------------
6045 -- Unchecked_Access --
6046 ----------------------
6053 Analyze_Access_Attribute;
6054 Check_Not_Incomplete_Type;
6056 -------------------------
6057 -- Unconstrained_Array --
6058 -------------------------
6061 Check_E0;
6062 Check_Type;
6063 Check_Not_Incomplete_Type;
6067 ------------------------------
6068 -- Universal_Literal_String --
6069 ------------------------------
6071 -- This is a GNAT specific attribute whose prefix must be a named
6072 -- number where the expression is either a single numeric literal,
6073 -- or a numeric literal immediately preceded by a minus sign. The
6074 -- result is equivalent to a string literal containing the text of
6075 -- the literal as it appeared in the source program with a possible
6076 -- leading minus sign.
6079 begin
6080 Check_E0;
6084 then
6087 else
6088 declare
6094 begin
6100 else
6105 Error_Attr
6109 -- Build string literal corresponding to source literal text
6111 Start_String;
6125 -- Now we rewrite the attribute with the string literal
6135 -------------------------
6136 -- Unrestricted_Access --
6137 -------------------------
6139 -- This is a GNAT specific attribute which is like Access except that
6140 -- all scope checks and checks for aliased views are omitted. It is
6141 -- documented as being equivalent to the use of the Address attribute
6142 -- followed by an unchecked conversion to the target access type.
6146 -- If from source, deal with relevant restrictions
6154 then
6163 -- It might seem reasonable to call Address_Checks here to apply the
6164 -- same set of semantic checks that we enforce for 'Address (after
6165 -- all we document Unrestricted_Access as being equivalent to the
6166 -- use of Address followed by an Unchecked_Conversion). However, if
6167 -- we do enable these checks, we get multiple failures in both the
6168 -- compiler run-time and in our regression test suite, so we leave
6169 -- out these checks for now. To be investigated further some time???
6171 -- Address_Checks;
6173 -- Now complete analysis using common access processing
6175 Analyze_Access_Attribute;
6177 ------------
6178 -- Update --
6179 ------------
6183 -- The common type of a multiple component update for a record
6186 -- A list used in the resolution of a record update. It contains the
6187 -- entities of all record components processed so far.
6190 -- Analyze and resolve array_component_association Assoc against the
6191 -- index of array type P_Type.
6194 -- Analyze and resolve record_component_association Comp against
6195 -- record type P_Type.
6197 ------------------------------------
6198 -- Analyze_Array_Component_Update --
6199 ------------------------------------
6208 begin
6209 -- The current association contains a sequence of indexes denoting
6210 -- an element of a multidimensional array:
6212 -- (Index_1, ..., Index_N)
6214 -- Examine each individual index and resolve it against the proper
6215 -- index type of the array.
6221 -- The use of others is illegal (SPARK RM 4.4.1(12))
6224 Error_Attr
6227 -- Otherwise analyze and resolve all indexes
6229 else
6238 -- Detect a case where the association either lacks an
6239 -- index or contains an extra index.
6242 Error_Msg_N
6250 -- The current association denotes either a single component or a
6251 -- range of components of a one dimensional array:
6253 -- 1, 2 .. 5
6255 -- Resolve the index or its high and low bounds (if range) against
6256 -- the proper index type of the array.
6258 else
6268 -- The use of others is illegal (SPARK RM 4.4.1(12))
6271 Error_Attr
6274 -- The index denotes a range of elements
6283 -- Add a range check to ensure that the bounds of the
6284 -- range are within the index type when this cannot be
6285 -- determined statically.
6295 -- Otherwise the index denotes a single element
6297 else
6300 -- Add a range check to ensure that the index is within
6301 -- the index type when it is not possible to determine
6302 -- this statically.
6314 -------------------------------------
6315 -- Analyze_Record_Component_Update --
6316 -------------------------------------
6323 begin
6324 -- Find the discriminant or component whose name corresponds to
6325 -- Comp. A simple character comparison is sufficient because all
6326 -- visible names within a record type are unique.
6332 -- Decorate the component reference by setting its entity
6333 -- and type for resolution purposes.
6343 -- Diagnose an illegal reference
6347 Error_Attr
6354 -- Mark this component as processed
6356 else
6361 -- The update aggregate mentions an entity that does not belong to
6362 -- the record type.
6364 else
6368 -- Verify the consistency of types when the current component is
6369 -- part of a miltiple component update.
6371 -- Comp_1, ..., Comp_N => <value>
6376 -- Save the type of the first component reference as the
6377 -- remaning references (if any) must resolve to this type.
6383 Error_Msg_N
6389 -- Local variables
6394 -- Start of processing for Update
6396 begin
6397 Check_E1;
6404 then
6414 -- Inspect the update aggregate, looking at all the associations and
6415 -- choices. Perform the following checks:
6417 -- 1) Legality of "others" in all cases
6418 -- 2) Legality of <>
6419 -- 3) Component legality for arrays
6420 -- 4) Component legality for records
6422 -- The remaining checks are performed on the expanded attribute
6427 -- The use of <> is illegal (SPARK RM 4.4.1(1))
6430 Error_Attr
6433 -- Otherwise process the association
6435 else
6443 -- Reset the common type used in a multiple component update
6444 -- as we are processing the contents of a new association.
6453 -- The use of others is illegal (SPARK RM 4.4.1(5))
6456 Error_Attr
6459 -- The name of a record component cannot appear in any
6460 -- other form.
6462 else
6463 Error_Msg_N
6475 -- The type of attribute 'Update is that of the prefix
6482 ---------
6483 -- Val --
6484 ---------
6487 begin
6488 Check_E1;
6489 Check_Discrete_Type;
6494 Check_SPARK_05_Restriction
6501 -- Note, we need a range check in general, but we wait for the
6502 -- Resolve call to do this, since we want to let Eval_Attribute
6503 -- have a chance to find an static illegality first.
6506 -----------
6507 -- Valid --
6508 -----------
6511 Check_E0;
6513 -- Ignore check for object if we have a 'Valid reference generated
6514 -- by the expanded code, since in some cases valid checks can occur
6515 -- on items that are names, but are not objects (e.g. attributes).
6525 -- If the attribute appears within the subtype's own predicate
6526 -- function, then issue a warning that this will cause infinite
6527 -- recursion.
6529 declare
6532 begin
6534 Error_Msg_N
6542 -------------------
6543 -- Valid_Scalars --
6544 -------------------
6547 Check_E0;
6551 -- Following checks are only for source types
6555 Error_Attr_P
6559 -- Not allowed for unchecked union type
6562 Error_Attr_P
6567 -----------
6568 -- Value --
6569 -----------
6572 begin
6573 Check_SPARK_05_Restriction_On_Attribute;
6574 Check_E1;
6575 Check_Scalar_Type;
6577 -- Case of enumeration type
6579 -- When an enumeration type appears in an attribute reference, all
6580 -- literals of the type are marked as referenced. This must only be
6581 -- done if the attribute reference appears in the current source.
6582 -- Otherwise the information on references may differ between a
6583 -- normal compilation and one that performs inlining.
6587 then
6590 -- Mark all enumeration literals as referenced, since the use of
6591 -- the Value attribute can implicitly reference any of the
6592 -- literals of the enumeration base type.
6594 declare
6596 begin
6604 -- Set Etype before resolving expression because expansion of
6605 -- expression may require enclosing type. Note that the type
6606 -- returned by 'Value is the base type of the prefix type.
6609 Validate_Non_Static_Attribute_Function_Call;
6611 -- Check restriction No_Fixed_IO
6615 then
6620 ----------------
6621 -- Value_Size --
6622 ----------------
6625 Check_E0;
6626 Check_Type;
6627 Check_Not_Incomplete_Type;
6630 -------------
6631 -- Version --
6632 -------------
6635 Check_E0;
6636 Check_Program_Unit;
6639 ------------------
6640 -- Wchar_T_Size --
6641 ------------------
6646 ----------------
6647 -- Wide_Image --
6648 ----------------
6651 begin
6652 Check_SPARK_05_Restriction_On_Attribute;
6653 Check_Scalar_Type;
6655 Check_E1;
6657 Validate_Non_Static_Attribute_Function_Call;
6659 -- Check restriction No_Fixed_IO
6663 then
6668 ---------------------
6669 -- Wide_Wide_Image --
6670 ---------------------
6673 begin
6674 Check_Scalar_Type;
6676 Check_E1;
6678 Validate_Non_Static_Attribute_Function_Call;
6680 -- Check restriction No_Fixed_IO
6684 then
6689 ----------------
6690 -- Wide_Value --
6691 ----------------
6694 begin
6695 Check_SPARK_05_Restriction_On_Attribute;
6696 Check_E1;
6697 Check_Scalar_Type;
6699 -- Set Etype before resolving expression because expansion
6700 -- of expression may require enclosing type.
6703 Validate_Non_Static_Attribute_Function_Call;
6705 -- Check restriction No_Fixed_IO
6709 then
6714 ---------------------
6715 -- Wide_Wide_Value --
6716 ---------------------
6719 begin
6720 Check_E1;
6721 Check_Scalar_Type;
6723 -- Set Etype before resolving expression because expansion
6724 -- of expression may require enclosing type.
6727 Validate_Non_Static_Attribute_Function_Call;
6729 -- Check restriction No_Fixed_IO
6733 then
6738 ---------------------
6739 -- Wide_Wide_Width --
6740 ---------------------
6743 Check_E0;
6744 Check_Scalar_Type;
6747 ----------------
6748 -- Wide_Width --
6749 ----------------
6752 Check_SPARK_05_Restriction_On_Attribute;
6753 Check_E0;
6754 Check_Scalar_Type;
6757 -----------
6758 -- Width --
6759 -----------
6762 Check_SPARK_05_Restriction_On_Attribute;
6763 Check_E0;
6764 Check_Scalar_Type;
6767 ---------------
6768 -- Word_Size --
6769 ---------------
6774 -----------
6775 -- Write --
6776 -----------
6779 Check_E2;
6786 -- All errors raise Bad_Attribute, so that we get out before any further
6787 -- damage occurs when an error is detected (for example, if we check for
6788 -- one attribute expression, and the check succeeds, we want to be able
6789 -- to proceed securely assuming that an expression is in fact present.
6791 -- Note: we set the attribute analyzed in this case to prevent any
6792 -- attempt at reanalysis which could generate spurious error msgs.
6794 exception
6801 --------------------
6802 -- Eval_Attribute --
6803 --------------------
6812 -- The type imposed by the context
6815 -- First expression, or Empty if none
6818 -- Second expression, or Empty if none
6821 -- Entity denoted by prefix
6824 -- The type of the prefix
6827 -- The base type of the prefix type
6830 -- The root type of the prefix type
6833 -- True if the result is Static. This is set by the general processing
6834 -- to true if the prefix is static, and all expressions are static. It
6835 -- can be reset as processing continues for particular attributes. This
6836 -- flag can still be True if the reference raises a constraint error.
6837 -- Is_Static_Expression (N) is set to follow this value as it is set
6838 -- and we could always reference this, but it is convenient to have a
6839 -- simple short name to use, since it is frequently referenced.
6842 -- Expressions for low and high bounds of type or array index referenced
6843 -- by First, Last, or Length attribute for array, set by Set_Bounds.
6846 -- Constraint error node used if we have an attribute reference has
6847 -- an argument that raises a constraint error. In this case we replace
6848 -- the attribute with a raise constraint_error node. This is important
6849 -- processing, since otherwise gigi might see an attribute which it is
6850 -- unprepared to deal with.
6853 -- If Bound is a reference to a discriminant of a task or protected type
6854 -- occurring within the object's body, rewrite attribute reference into
6855 -- a reference to the corresponding discriminal. Use for the expansion
6856 -- of checks against bounds of entry family index subtypes.
6859 -- In case where the attribute is not foldable, the expressions, if
6860 -- any, of the attribute, are in a non-static context. This procedure
6861 -- performs the required additional checks.
6864 -- Determines if the given type has compile time known bounds. Note
6865 -- that we enter the case statement even in cases where the prefix
6866 -- type does NOT have known bounds, so it is important to guard any
6867 -- attempt to evaluate both bounds with a call to this function.
6870 -- This procedure is called when the attribute N has a non-static
6871 -- but compile time known value given by Val. It includes the
6872 -- necessary checks for out of range values.
6875 -- Computes the Fore value for the current attribute prefix, which is
6876 -- known to be a static fixed-point type. Used by Fore and Width.
6879 -- Returns the Mantissa value for the prefix type
6882 -- Used for First, Last and Length attributes applied to an array or
6883 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
6884 -- and high bound expressions for the index referenced by the attribute
6885 -- designator (i.e. the first index if no expression is present, and the
6886 -- N'th index if the value N is present as an expression). Also used for
6887 -- First and Last of scalar types and for First_Valid and Last_Valid.
6888 -- Static is reset to False if the type or index type is not statically
6889 -- constrained.
6892 -- Verify that the prefix of a potentially static array attribute
6893 -- satisfies the conditions of 4.9 (14).
6895 -----------------------------------
6896 -- Check_Concurrent_Discriminant --
6897 -----------------------------------
6901 -- The concurrent (task or protected) type
6903 begin
6907 then
6912 -- Find discriminant of original concurrent type, and use
6913 -- its current discriminal, which is the renaming within
6914 -- the task/protected body.
6917 New_Occurrence_Of
6923 -----------------------
6924 -- Check_Expressions --
6925 -----------------------
6929 begin
6937 ----------------------------------
6938 -- Compile_Time_Known_Attribute --
6939 ----------------------------------
6944 begin
6947 -- Check that result is in bounds of the type if it is static
6953 Apply_Compile_Time_Constraint_Error
6959 else
6964 -------------------------------
6965 -- Compile_Time_Known_Bounds --
6966 -------------------------------
6969 begin
6970 return
6972 and then
6976 ----------------
6977 -- Fore_Value --
6978 ----------------
6980 -- Note that the Fore calculation is based on the actual values
6981 -- of the bounds, and does not take into account possible rounding.
6992 begin
6993 -- Bounds are given in terms of small units, so first compute
6994 -- proper values as reals.
6999 -- Loop to compute proper value if more than one digit required
7009 --------------
7010 -- Mantissa --
7011 --------------
7013 -- Table of mantissa values accessed by function Computed using
7014 -- the relation:
7016 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
7018 -- where D is T'Digits (RM83 3.5.7)
7063 begin
7064 return
7068 ----------------
7069 -- Set_Bounds --
7070 ----------------
7077 begin
7078 -- For a string literal subtype, we have to construct the bounds.
7079 -- Valid Ada code never applies attributes to string literals, but
7080 -- it is convenient to allow the expander to generate attribute
7081 -- references of this type (e.g. First and Last applied to a string
7082 -- literal).
7084 -- Note that the whole point of the E_String_Literal_Subtype is to
7085 -- avoid this construction of bounds, but the cases in which we
7086 -- have to materialize them are rare enough that we don't worry.
7088 -- The low bound is simply the low bound of the base type. The
7089 -- high bound is computed from the length of the string and this
7090 -- low bound.
7096 Hi_Bound :=
7098 Intval =>
7105 -- For non-array case, just get bounds of scalar type
7110 -- For a fixed-point type, we must freeze to get the attributes
7111 -- of the fixed-point type set now so we can reference them.
7117 then
7121 -- For array case, get type of proper index
7123 else
7126 else
7135 -- If no index type, get out (some other error occurred, and
7136 -- we don't have enough information to complete the job).
7147 -- A discrete range in an index constraint is allowed to be a
7148 -- subtype indication. This is syntactically a pain, but should
7149 -- not propagate to the entity for the corresponding index subtype.
7150 -- After checking that the subtype indication is legal, the range
7151 -- of the subtype indication should be transfered to the entity.
7152 -- The attributes for the bounds should remain the simple retrievals
7153 -- that they are now.
7158 -- If subtype is non-static, result is definitely non-static
7164 -- Subtype is static, does it raise CE?
7171 -------------------------------
7172 -- Statically_Denotes_Entity --
7173 -------------------------------
7178 begin
7181 else
7185 return
7190 -- Start of processing for Eval_Attribute
7192 begin
7193 -- Initialize result as non-static, will be reset if appropriate
7198 -- Acquire first two expressions (at the moment, no attributes take more
7199 -- than two expressions in any case).
7204 else
7209 -- Special processing for Enabled attribute. This attribute has a very
7210 -- special prefix, and the easiest way to avoid lots of special checks
7211 -- to protect this special prefix from causing trouble is to deal with
7212 -- this attribute immediately and be done with it.
7216 -- We skip evaluation if the expander is not active. This is not just
7217 -- an optimization. It is of key importance that we not rewrite the
7218 -- attribute in a generic template, since we want to pick up the
7219 -- setting of the check in the instance, and testing expander active
7220 -- is as easy way of doing this as any.
7223 declare
7227 begin
7231 else
7235 else
7246 -- Attribute 'Img applied to a static enumeration value is static, and
7247 -- we will do the folding right here (things get confused if we let this
7248 -- case go through the normal circuitry).
7254 then
7255 declare
7259 begin
7260 Start_String;
7274 -- Special processing for cases where the prefix is an object. For
7275 -- this purpose, a string literal counts as an object (attributes
7276 -- of string literals can only appear in generated code).
7280 -- For Component_Size, the prefix is an array object, and we apply
7281 -- the attribute to the type of the object. This is allowed for
7282 -- both unconstrained and constrained arrays, since the bounds
7283 -- have no influence on the value of this attribute.
7288 -- For First and Last, the prefix is an array object, and we apply
7289 -- the attribute to the type of the array, but we need a constrained
7290 -- type for this, so we use the actual subtype if available.
7294 Id = Attribute_Length
7295 then
7296 declare
7299 begin
7303 -- If we have an unconstrained type we cannot fold
7305 else
7306 Check_Expressions;
7311 -- For Size, give size of object if available, otherwise we
7312 -- cannot fold Size.
7317 then
7321 else
7322 Check_Expressions;
7326 -- For Alignment, give size of object if available, otherwise we
7327 -- cannot fold Alignment.
7332 then
7336 else
7337 Check_Expressions;
7341 -- For Lock_Free, we apply the attribute to the type of the object.
7342 -- This is allowed since we have already verified that the type is a
7343 -- protected type.
7348 -- No other attributes for objects are folded
7350 else
7351 Check_Expressions;
7355 -- Cases where P is not an object. Cannot do anything if P is not the
7356 -- name of an entity.
7359 Check_Expressions;
7362 -- Otherwise get prefix entity
7364 else
7368 -- If we are asked to evaluate an attribute where the prefix is a
7369 -- non-frozen generic actual type whose RM_Size is still set to zero,
7370 -- then abandon the effort.
7377 -- However, the attribute Unconstrained_Array must be evaluated,
7378 -- since it is documented to be a static attribute (and can for
7379 -- example appear in a Compile_Time_Warning pragma). The frozen
7380 -- status of the type does not affect its evaluation.
7383 then
7387 -- At this stage P_Entity is the entity to which the attribute
7388 -- is to be applied. This is usually simply the entity of the
7389 -- prefix, except in some cases of attributes for objects, where
7390 -- as described above, we apply the attribute to the object type.
7392 -- Here is where we make sure that static attributes are properly
7393 -- marked as such. These are attributes whose prefix is a static
7394 -- scalar subtype, whose result is scalar, and whose arguments, if
7395 -- present, are static scalar expressions. Note that such references
7396 -- are static expressions even if they raise Constraint_Error.
7398 -- For example, Boolean'Pos (1/0 = 0) is a static expression, even
7399 -- though evaluating it raises constraint error. This means that a
7400 -- declaration like:
7402 -- X : constant := (if True then 1 else Boolean'Pos (1/0 = 0));
7404 -- is legal, since here this expression appears in a statically
7405 -- unevaluated position, so it does not actually raise an exception.
7411 and then
7415 and then
7419 then
7424 -- First foldable possibility is a scalar or array type (RM 4.9(7))
7425 -- that is not generic (generic types are eliminated by RM 4.9(25)).
7426 -- Note we allow non-static non-generic types at this stage as further
7427 -- described below.
7432 then
7435 -- Second foldable possibility is an array object (RM 4.9(8))
7440 then
7443 -- If the entity is an array constant with an unconstrained nominal
7444 -- subtype then get the type from the initial value. If the value has
7445 -- been expanded into assignments, there is no expression and the
7446 -- attribute reference remains dynamic.
7448 -- We could do better here and retrieve the type ???
7452 then
7455 else
7460 -- Definite must be folded if the prefix is not a generic type, that
7461 -- is to say if we are within an instantiation. Same processing applies
7462 -- to the GNAT attributes Atomic_Always_Lock_Free, Has_Discriminants,
7463 -- Lock_Free, Type_Class, Has_Tagged_Value, and Unconstrained_Array.
7475 then
7478 -- We can fold 'Size applied to a type if the size is known (as happens
7479 -- for a size from an attribute definition clause). At this stage, this
7480 -- can happen only for types (e.g. record types) for which the size is
7481 -- always non-static. We exclude generic types from consideration (since
7482 -- they have bogus sizes set within templates).
7488 then
7492 -- We can fold 'Alignment applied to a type if the alignment is known
7493 -- (as happens for an alignment from an attribute definition clause).
7494 -- At this stage, this can happen only for types (e.g. record types) for
7495 -- which the size is always non-static. We exclude generic types from
7496 -- consideration (since they have bogus sizes set within templates).
7502 then
7506 -- If this is an access attribute that is known to fail accessibility
7507 -- check, rewrite accordingly.
7511 then
7518 -- No other cases are foldable (they certainly aren't static, and at
7519 -- the moment we don't try to fold any cases other than the ones above).
7521 else
7522 Check_Expressions;
7526 -- If either attribute or the prefix is Any_Type, then propagate
7527 -- Any_Type to the result and don't do anything else at all.
7532 then
7537 -- Scalar subtype case. We have not yet enforced the static requirement
7538 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
7539 -- of non-static attribute references (e.g. S'Digits for a non-static
7540 -- floating-point type, which we can compute at compile time).
7542 -- Note: this folding of non-static attributes is not simply a case of
7543 -- optimization. For many of the attributes affected, Gigi cannot handle
7544 -- the attribute and depends on the front end having folded them away.
7546 -- Note: although we don't require staticness at this stage, we do set
7547 -- the Static variable to record the staticness, for easy reference by
7548 -- those attributes where it matters (e.g. Succ and Pred), and also to
7549 -- be used to ensure that non-static folded things are not marked as
7550 -- being static (a check that is done right at the end).
7555 -- If the root type or base type is generic, then we cannot fold. This
7556 -- test is needed because subtypes of generic types are not always
7557 -- marked as being generic themselves (which seems odd???)
7561 then
7573 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
7574 -- since we can't do anything with unconstrained arrays. In addition,
7575 -- only the First, Last and Length attributes are possibly static.
7577 -- Atomic_Always_Lock_Free, Definite, Has_Access_Values,
7578 -- Has_Discriminants, Has_Tagged_Values, Lock_Free, Type_Class, and
7579 -- Unconstrained_Array are again exceptions, because they apply as well
7580 -- to unconstrained types.
7582 -- In addition Component_Size is an exception since it is possibly
7583 -- foldable, even though it is never static, and it does apply to
7584 -- unconstrained arrays. Furthermore, it is essential to fold this
7585 -- in the packed case, since otherwise the value will be incorrect.
7595 Id = Attribute_Component_Size
7596 then
7605 then
7606 Check_Expressions;
7610 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
7611 -- scalar case, we hold off on enforcing staticness, since there are
7612 -- cases which we can fold at compile time even though they are not
7613 -- static (e.g. 'Length applied to a static index, even though other
7614 -- non-static indexes make the array type non-static). This is only
7615 -- an optimization, but it falls out essentially free, so why not.
7616 -- Again we compute the variable Static for easy reference later
7617 -- (note that no array attributes are static in Ada 83).
7619 -- We also need to set Static properly for subsequent legality checks
7620 -- which might otherwise accept non-static constants in contexts
7621 -- where they are not legal.
7623 Static :=
7627 declare
7630 begin
7633 -- The expression is static if the array type is constrained
7634 -- by given bounds, and not by an initial expression. Constant
7635 -- strings are static in any case.
7638 Static :=
7654 -- If however the index type is generic, or derived from
7655 -- one, attributes cannot be folded.
7659 then
7668 -- Check any expressions that are present. Note that these expressions,
7669 -- depending on the particular attribute type, are either part of the
7670 -- attribute designator, or they are arguments in a case where the
7671 -- attribute reference returns a function. In the latter case, the
7672 -- rule in (RM 4.9(22)) applies and in particular requires the type
7673 -- of the expressions to be scalar in order for the attribute to be
7674 -- considered to be static.
7676 declare
7679 begin
7684 -- If expression is not static, then the attribute reference
7685 -- result certainly cannot be static.
7696 -- If the result is not known at compile time, or is not of
7697 -- a scalar type, then the result is definitely not static,
7698 -- so we can quit now.
7702 then
7703 -- An odd special case, if this is a Pos attribute, this
7704 -- is where we need to apply a range check since it does
7705 -- not get done anywhere else.
7713 Check_Expressions;
7716 -- If the expression raises a constraint error, then so does
7717 -- the attribute reference. We keep going in this case because
7718 -- we are still interested in whether the attribute reference
7719 -- is static even if it is not static.
7734 -- Deal with the case of a static attribute reference that raises
7735 -- constraint error. The Raises_Constraint_Error flag will already
7736 -- have been set, and the Static flag shows whether the attribute
7737 -- reference is static. In any case we certainly can't fold such an
7738 -- attribute reference.
7740 -- Note that the rewriting of the attribute node with the constraint
7741 -- error node is essential in this case, because otherwise Gigi might
7742 -- blow up on one of the attributes it never expects to see.
7744 -- The constraint_error node must have the type imposed by the context,
7745 -- to avoid spurious errors in the enclosing expression.
7748 CE_Node :=
7753 Check_Expressions;
7759 -- At this point we have a potentially foldable attribute reference.
7760 -- If Static is set, then the attribute reference definitely obeys
7761 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
7762 -- folded. If Static is not set, then the attribute may or may not
7763 -- be foldable, and the individual attribute processing routines
7764 -- test Static as required in cases where it makes a difference.
7766 -- In the case where Static is not set, we do know that all the
7767 -- expressions present are at least known at compile time (we assumed
7768 -- above that if this was not the case, then there was no hope of static
7769 -- evaluation). However, we did not require that the bounds of the
7770 -- prefix type be compile time known, let alone static). That's because
7771 -- there are many attributes that can be computed at compile time on
7772 -- non-static subtypes, even though such references are not static
7773 -- expressions.
7775 -- For VAX float, the root type is an IEEE type. So make sure to use the
7776 -- base type instead of the root-type for floating point attributes.
7780 -- Attributes related to Ada 2012 iterators (placeholder ???)
7782 when Attribute_Constant_Indexing |
7783 Attribute_Default_Iterator |
7784 Attribute_Implicit_Dereference |
7785 Attribute_Iterator_Element |
7786 Attribute_Iterable |
7789 -- Internal attributes used to deal with Ada 2012 delayed aspects.
7790 -- These were already rejected by the parser. Thus they shouldn't
7791 -- appear here.
7796 --------------
7797 -- Adjacent --
7798 --------------
7801 Fold_Ureal
7803 Eval_Fat.Adjacent
7805 Static);
7807 ---------
7808 -- Aft --
7809 ---------
7814 ---------------
7815 -- Alignment --
7816 ---------------
7821 begin
7822 -- Fold if alignment is set and not otherwise
7829 -----------------------------
7830 -- Atomic_Always_Lock_Free --
7831 -----------------------------
7833 -- Atomic_Always_Lock_Free attribute is a Boolean, thus no need to fold
7834 -- here.
7837 declare
7839 Boolean_Literals
7840 (Support_Atomic_Primitives_On_Target
7843 begin
7846 -- Analyze and resolve as boolean. Note that this attribute is a
7847 -- static attribute in GNAT.
7854 ---------
7855 -- Bit --
7856 ---------
7858 -- Bit can never be folded
7863 ------------------
7864 -- Body_Version --
7865 ------------------
7867 -- Body_version can never be static
7872 -------------
7873 -- Ceiling --
7874 -------------
7877 Fold_Ureal
7880 --------------------
7881 -- Component_Size --
7882 --------------------
7889 -------------
7890 -- Compose --
7891 -------------
7894 Fold_Ureal
7897 Static);
7899 -----------------
7900 -- Constrained --
7901 -----------------
7903 -- Constrained is never folded for now, there may be cases that
7904 -- could be handled at compile time. To be looked at later.
7908 -- The expander might fold it and set the static flag accordingly,
7909 -- but with expansion disabled (as in ASIS), it remains as an
7910 -- attribute reference, and this reference is not static.
7915 ---------------
7916 -- Copy_Sign --
7917 ---------------
7920 Fold_Ureal
7922 Eval_Fat.Copy_Sign
7924 Static);
7926 --------------
7927 -- Definite --
7928 --------------
7935 -----------
7936 -- Delta --
7937 -----------
7942 ------------
7943 -- Denorm --
7944 ------------
7947 Fold_Uint
7950 ---------------------
7951 -- Descriptor_Size --
7952 ---------------------
7957 ------------
7958 -- Digits --
7959 ------------
7964 ----------
7965 -- Emax --
7966 ----------
7970 -- Ada 83 attribute is defined as (RM83 3.5.8)
7972 -- T'Emax = 4 * T'Mantissa
7976 --------------
7977 -- Enum_Rep --
7978 --------------
7982 -- For an enumeration type with a non-standard representation use
7983 -- the Enumeration_Rep field of the proper constant. Note that this
7984 -- will not work for types Character/Wide_[Wide-]Character, since no
7985 -- real entities are created for the enumeration literals, but that
7986 -- does not matter since these two types do not have non-standard
7987 -- representations anyway.
7991 then
7994 -- For enumeration types with standard representations and all
7995 -- other cases (i.e. all integer and modular types), Enum_Rep
7996 -- is equivalent to Pos.
7998 else
8002 --------------
8003 -- Enum_Val --
8004 --------------
8009 begin
8010 -- We have something like Enum_Type'Enum_Val (23), so search for a
8011 -- corresponding value in the list of Enum_Rep values for the type.
8014 loop
8023 Apply_Compile_Time_Constraint_Error
8025 CE_Range_Check_Failed,
8032 -------------
8033 -- Epsilon --
8034 -------------
8038 -- Ada 83 attribute is defined as (RM83 3.5.8)
8040 -- T'Epsilon = 2.0**(1 - T'Mantissa)
8044 --------------
8045 -- Exponent --
8046 --------------
8052 -----------
8053 -- First --
8054 -----------
8057 begin
8058 Set_Bounds;
8063 else
8067 else
8072 -----------------
8073 -- First_Valid --
8074 -----------------
8077 begin
8080 then
8081 declare
8084 begin
8087 else
8092 else
8093 Set_Bounds;
8098 -----------------
8099 -- Fixed_Value --
8100 -----------------
8105 -----------
8106 -- Floor --
8107 -----------
8110 Fold_Ureal
8113 ----------
8114 -- Fore --
8115 ----------
8122 --------------
8123 -- Fraction --
8124 --------------
8127 Fold_Ureal
8130 -----------------------
8131 -- Has_Access_Values --
8132 -----------------------
8139 -----------------------
8140 -- Has_Discriminants --
8141 -----------------------
8148 ----------------------
8149 -- Has_Same_Storage --
8150 ----------------------
8155 -----------------------
8156 -- Has_Tagged_Values --
8157 -----------------------
8164 --------------
8165 -- Identity --
8166 --------------
8171 -----------
8172 -- Image --
8173 -----------
8175 -- Image is a scalar attribute, but is never static, because it is
8176 -- not a static function (having a non-scalar argument (RM 4.9(22))
8177 -- However, we can constant-fold the image of an enumeration literal
8178 -- if names are available.
8184 and then not Global_Discard_Names
8185 then
8186 declare
8189 begin
8190 Start_String;
8201 -------------------
8202 -- Integer_Value --
8203 -------------------
8205 -- We never try to fold Integer_Value (though perhaps we could???)
8210 -------------------
8211 -- Invalid_Value --
8212 -------------------
8214 -- Invalid_Value is a scalar attribute that is never static, because
8215 -- the value is by design out of range.
8220 -----------
8221 -- Large --
8222 -----------
8226 -- For fixed-point, we use the identity:
8228 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
8233 Left_Opnd =>
8235 Left_Opnd =>
8237 Left_Opnd =>
8239 Right_Opnd =>
8245 Right_Opnd =>
8250 -- Floating-point (Ada 83 compatibility)
8252 else
8253 -- Ada 83 attribute is defined as (RM83 3.5.8)
8255 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
8257 -- where
8259 -- T'Emax = 4 * T'Mantissa
8261 Fold_Ureal
8267 ---------------
8268 -- Lock_Free --
8269 ---------------
8274 begin
8277 -- Analyze and resolve as boolean. Note that this attribute is a
8278 -- static attribute in GNAT.
8285 ----------
8286 -- Last --
8287 ----------
8290 begin
8291 Set_Bounds;
8296 else
8300 else
8305 ----------------
8306 -- Last_Valid --
8307 ----------------
8310 begin
8313 then
8314 declare
8317 begin
8320 else
8325 else
8326 Set_Bounds;
8331 ------------------
8332 -- Leading_Part --
8333 ------------------
8336 Fold_Ureal
8338 Eval_Fat.Leading_Part
8340 Static);
8342 ------------
8343 -- Length --
8344 ------------
8349 begin
8350 -- If any index type is a formal type, or derived from one, the
8351 -- bounds are not static. Treating them as static can produce
8352 -- spurious warnings or improper constant folding.
8363 Set_Bounds;
8365 -- For two compile time values, we can compute length
8369 then
8372 Static);
8375 -- One more case is where Hi_Bound and Lo_Bound are compile-time
8376 -- comparable, and we can figure out the difference between them.
8378 declare
8381 begin
8382 case
8383 Compile_Time_Compare
8385 is
8403 ----------------
8404 -- Loop_Entry --
8405 ----------------
8407 -- Loop_Entry acts as an alias of a constant initialized to the prefix
8408 -- of the said attribute at the point of entry into the related loop. As
8409 -- such, the attribute reference does not need to be evaluated because
8410 -- the prefix is the one that is evaluted.
8415 -------------
8416 -- Machine --
8417 -------------
8420 Fold_Ureal
8422 Eval_Fat.Machine
8424 Static);
8426 ------------------
8427 -- Machine_Emax --
8428 ------------------
8433 ------------------
8434 -- Machine_Emin --
8435 ------------------
8440 ----------------------
8441 -- Machine_Mantissa --
8442 ----------------------
8447 -----------------------
8448 -- Machine_Overflows --
8449 -----------------------
8453 -- Always true for fixed-point
8458 -- Floating point case
8460 else
8463 Static);
8466 -------------------
8467 -- Machine_Radix --
8468 -------------------
8474 then
8476 else
8480 -- All floating-point type always have radix 2
8482 else
8486 ----------------------
8487 -- Machine_Rounding --
8488 ----------------------
8490 -- Note: for the folding case, it is fine to treat Machine_Rounding
8491 -- exactly the same way as Rounding, since this is one of the allowed
8492 -- behaviors, and performance is not an issue here. It might be a bit
8493 -- better to give the same result as it would give at run time, even
8494 -- though the non-determinism is certainly permitted.
8497 Fold_Ureal
8500 --------------------
8501 -- Machine_Rounds --
8502 --------------------
8506 -- Always False for fixed-point
8511 -- Else yield proper floating-point result
8513 else
8514 Fold_Uint
8516 Static);
8519 ------------------
8520 -- Machine_Size --
8521 ------------------
8523 -- Note: Machine_Size is identical to Object_Size
8528 begin
8534 --------------
8535 -- Mantissa --
8536 --------------
8540 -- Fixed-point mantissa
8544 -- Compile time foldable case
8547 and then
8549 then
8550 -- The calculation of the obsolete Ada 83 attribute Mantissa
8551 -- is annoying, because of AI00143, quoted here:
8553 -- !question 84-01-10
8555 -- Consider the model numbers for F:
8557 -- type F is delta 1.0 range -7.0 .. 8.0;
8559 -- The wording requires that F'MANTISSA be the SMALLEST
8560 -- integer number for which each bound of the specified
8561 -- range is either a model number or lies at most small
8562 -- distant from a model number. This means F'MANTISSA
8563 -- is required to be 3 since the range -7.0 .. 7.0 fits
8564 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
8565 -- number, namely, 7. Is this analysis correct? Note that
8566 -- this implies the upper bound of the range is not
8567 -- represented as a model number.
8569 -- !response 84-03-17
8571 -- The analysis is correct. The upper and lower bounds for
8572 -- a fixed point type can lie outside the range of model
8573 -- numbers.
8575 declare
8582 begin
8588 -- If the Bound is exactly a model number, i.e. a multiple
8589 -- of Small, then we back it off by one to get the integer
8590 -- value that must be representable.
8596 -- Now find corresponding size = Mantissa value
8606 else
8607 -- The case of dynamic bounds cannot be evaluated at compile
8608 -- time. Instead we use a runtime routine (see Exp_Attr).
8613 -- Floating-point Mantissa
8615 else
8619 ---------
8620 -- Max --
8621 ---------
8624 begin
8626 Fold_Ureal
8628 else
8633 ----------------------------------
8634 -- Max_Alignment_For_Allocation --
8635 ----------------------------------
8637 -- Max_Alignment_For_Allocation is usually the Alignment. However,
8638 -- arrays are allocated with dope, so we need to take into account both
8639 -- the alignment of the array, which comes from the component alignment,
8640 -- and the alignment of the dope. Also, if the alignment is unknown, we
8641 -- use the max (it's OK to be pessimistic).
8644 declare
8646 begin
8649 then
8656 ----------------------------------
8657 -- Max_Size_In_Storage_Elements --
8658 ----------------------------------
8660 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
8661 -- Storage_Unit boundary. We can fold any cases for which the size
8662 -- is known by the front end.
8668 System_Storage_Unit,
8669 Static);
8672 --------------------
8673 -- Mechanism_Code --
8674 --------------------
8677 declare
8682 begin
8686 else
8701 ---------
8702 -- Min --
8703 ---------
8706 begin
8708 Fold_Ureal
8710 else
8711 Fold_Uint
8716 ---------
8717 -- Mod --
8718 ---------
8721 Fold_Uint
8724 -----------
8725 -- Model --
8726 -----------
8729 Fold_Ureal
8732 ----------------
8733 -- Model_Emin --
8734 ----------------
8739 -------------------
8740 -- Model_Epsilon --
8741 -------------------
8746 --------------------
8747 -- Model_Mantissa --
8748 --------------------
8753 -----------------
8754 -- Model_Small --
8755 -----------------
8760 -------------
8761 -- Modulus --
8762 -------------
8767 --------------------
8768 -- Null_Parameter --
8769 --------------------
8771 -- Cannot fold, we know the value sort of, but the whole point is
8772 -- that there is no way to talk about this imaginary value except
8773 -- by using the attribute, so we leave it the way it is.
8778 -----------------
8779 -- Object_Size --
8780 -----------------
8782 -- The Object_Size attribute for a type returns the Esize of the
8783 -- type and can be folded if this value is known.
8788 begin
8794 ----------------------
8795 -- Overlaps_Storage --
8796 ----------------------
8801 -------------------------
8802 -- Passed_By_Reference --
8803 -------------------------
8805 -- Scalar types are never passed by reference
8810 ---------
8811 -- Pos --
8812 ---------
8817 ----------
8818 -- Pred --
8819 ----------
8822 begin
8823 -- Floating-point case
8826 Fold_Ureal
8829 -- Fixed-point case
8832 Fold_Ureal
8835 -- Modular integer case (wraps)
8840 -- Other scalar cases
8842 else
8848 then
8849 Apply_Compile_Time_Constraint_Error
8851 CE_Overflow_Check_Failed,
8855 Check_Expressions;
8863 -----------
8864 -- Range --
8865 -----------
8867 -- No processing required, because by this stage, Range has been
8868 -- replaced by First .. Last, so this branch can never be taken.
8873 ------------------
8874 -- Range_Length --
8875 ------------------
8878 Set_Bounds;
8880 -- Can fold if both bounds are compile time known
8884 then
8886 UI_Max
8888 Static);
8891 -- One more case is where Hi_Bound and Lo_Bound are compile-time
8892 -- comparable, and we can figure out the difference between them.
8894 declare
8897 begin
8898 case
8899 Compile_Time_Compare
8901 is
8918 ---------
8919 -- Ref --
8920 ---------
8925 ---------------
8926 -- Remainder --
8927 ---------------
8933 begin
8935 Apply_Compile_Time_Constraint_Error
8937 CE_Overflow_Check_Failed,
8940 Check_Expressions;
8947 -----------------
8948 -- Restriction --
8949 -----------------
8952 begin
8957 -----------
8958 -- Round --
8959 -----------
8962 declare
8966 begin
8967 -- First we get the (exact result) in units of small
8971 -- Now round that exactly to an integer
8975 -- Finally the result is obtained by converting back to real
8980 --------------
8981 -- Rounding --
8982 --------------
8985 Fold_Ureal
8988 ---------------
8989 -- Safe_Emax --
8990 ---------------
8995 ----------------
8996 -- Safe_First --
8997 ----------------
9002 ----------------
9003 -- Safe_Large --
9004 ----------------
9008 Fold_Ureal
9010 else
9014 ---------------
9015 -- Safe_Last --
9016 ---------------
9021 ----------------
9022 -- Safe_Small --
9023 ----------------
9027 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
9028 -- for fixed-point, since is the same as Small, but we implement
9029 -- it for backwards compatibility.
9034 -- Ada 83 Safe_Small for floating-point cases
9036 else
9040 -----------
9041 -- Scale --
9042 -----------
9047 -------------
9048 -- Scaling --
9049 -------------
9052 Fold_Ureal
9054 Eval_Fat.Scaling
9056 Static);
9058 ------------------
9059 -- Signed_Zeros --
9060 ------------------
9063 Fold_Uint
9066 ----------
9067 -- Size --
9068 ----------
9070 -- Size attribute returns the RM size. All scalar types can be folded,
9071 -- as well as any types for which the size is known by the front end,
9072 -- including any type for which a size attribute is specified. This is
9073 -- one of the places where it is annoying that a size of zero means two
9074 -- things (zero size for scalars, unspecified size for non-scalars).
9079 begin
9082 -- VADS_Size case
9085 declare
9088 begin
9089 -- If a size clause applies, then use the size from it.
9090 -- This is one of the rare cases where we can use the
9091 -- Size_Clause field for a subtype when Has_Size_Clause
9092 -- is False. Consider:
9094 -- type x is range 1 .. 64;
9095 -- for x'size use 12;
9096 -- subtype y is x range 0 .. 3;
9098 -- Here y has a size clause inherited from x, but normally
9099 -- it does not apply, and y'size is 2. However, y'VADS_Size
9100 -- is indeed 12 and not 2.
9104 then
9107 -- If no size is specified, then we simply use the object
9108 -- size in the VADS_Size case (e.g. Natural'Size is equal
9109 -- to Integer'Size, not one less).
9111 else
9116 -- Normal case (Size) in which case we want the RM_Size
9118 else
9124 -----------
9125 -- Small --
9126 -----------
9130 -- The floating-point case is present only for Ada 83 compatibility.
9131 -- Note that strictly this is an illegal addition, since we are
9132 -- extending an Ada 95 defined attribute, but we anticipate an
9133 -- ARG ruling that will permit this.
9137 -- Ada 83 attribute is defined as (RM83 3.5.8)
9139 -- T'Small = 2.0**(-T'Emax - 1)
9141 -- where
9143 -- T'Emax = 4 * T'Mantissa
9147 -- Normal Ada 95 fixed-point case
9149 else
9153 -----------------
9154 -- Stream_Size --
9155 -----------------
9160 ----------
9161 -- Succ --
9162 ----------
9165 begin
9166 -- Floating-point case
9169 Fold_Ureal
9172 -- Fixed-point case
9177 -- Modular integer case (wraps)
9182 -- Other scalar cases
9184 else
9190 then
9191 Apply_Compile_Time_Constraint_Error
9193 CE_Overflow_Check_Failed,
9197 Check_Expressions;
9199 else
9205 ----------------
9206 -- Truncation --
9207 ----------------
9210 Fold_Ureal
9213 Static);
9215 ----------------
9216 -- Type_Class --
9217 ----------------
9223 begin
9254 -- We treat protected types like task types. It would make more
9255 -- sense to have another enumeration value, but after all the
9256 -- whole point of this feature is to be exactly DEC compatible,
9257 -- and changing the type Type_Class would not meet this requirement.
9262 -- Not clear if there are any other possibilities, but if there
9263 -- are, then we will treat them as the address case.
9265 else
9272 -----------------------
9273 -- Unbiased_Rounding --
9274 -----------------------
9277 Fold_Ureal
9280 Static);
9282 -------------------------
9283 -- Unconstrained_Array --
9284 -------------------------
9289 begin
9291 Boolean_Literals (
9295 -- Analyze and resolve as boolean, note that this attribute is
9296 -- a static attribute in GNAT.
9303 -- Attribute Update is never static
9308 ---------------
9309 -- VADS_Size --
9310 ---------------
9312 -- Processing is shared with Size
9314 ---------
9315 -- Val --
9316 ---------
9319 begin
9321 or else
9323 then
9324 Apply_Compile_Time_Constraint_Error
9326 CE_Range_Check_Failed,
9329 Check_Expressions;
9332 else
9337 ----------------
9338 -- Value_Size --
9339 ----------------
9341 -- The Value_Size attribute for a type returns the RM size of the type.
9342 -- This an always be folded for scalar types, and can also be folded for
9343 -- non-scalar types if the size is set. This is one of the places where
9344 -- it is annoying that a size of zero means two things!
9348 begin
9354 -------------
9355 -- Version --
9356 -------------
9358 -- Version can never be static
9363 ----------------
9364 -- Wide_Image --
9365 ----------------
9367 -- Wide_Image is a scalar attribute, but is never static, because it
9368 -- is not a static function (having a non-scalar argument (RM 4.9(22))
9373 ---------------------
9374 -- Wide_Wide_Image --
9375 ---------------------
9377 -- Wide_Wide_Image is a scalar attribute but is never static, because it
9378 -- is not a static function (having a non-scalar argument (RM 4.9(22)).
9383 ---------------------
9384 -- Wide_Wide_Width --
9385 ---------------------
9387 -- Processing for Wide_Wide_Width is combined with Width
9389 ----------------
9390 -- Wide_Width --
9391 ----------------
9393 -- Processing for Wide_Width is combined with Width
9395 -----------
9396 -- Width --
9397 -----------
9399 -- This processing also handles the case of Wide_[Wide_]Width
9401 when Attribute_Width |
9402 Attribute_Wide_Width |
9404 begin
9407 -- Floating-point types
9411 -- Width is zero for a null range (RM 3.5 (38))
9415 then
9418 else
9419 -- For floating-point, we have +N.dddE+nnn where length
9420 -- of ddd is determined by type'Digits - 1, but is one
9421 -- if Digits is one (RM 3.5 (33)).
9423 -- nnn is set to 2 for Short_Float and Float (32 bit
9424 -- floats), and 3 for Long_Float and Long_Long_Float.
9425 -- For machines where Long_Long_Float is the IEEE
9426 -- extended precision type, the exponent takes 4 digits.
9428 declare
9432 begin
9437 else
9445 -- Fixed-point types
9449 -- Width is zero for a null range (RM 3.5 (38))
9453 then
9456 -- The non-null case depends on the specific real type
9458 else
9459 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
9461 Fold_Uint
9463 Static);
9466 -- Discrete types
9468 else
9469 declare
9479 begin
9480 -- Empty ranges
9485 -- Width for types derived from Standard.Character
9486 -- and Standard.Wide_[Wide_]Character.
9491 -- Set W larger if needed
9495 -- All wide characters look like Hex_hhhhhhhh
9499 -- No need to compute this more than once
9503 else
9506 -- Test for all cases where Character'Image
9507 -- yields an image that is longer than three
9508 -- characters. First the cases of Reserved_xxx
9509 -- names (length = 12).
9512 when Reserved_128 | Reserved_129 |
9513 Reserved_132 | Reserved_153
9516 when BS | HT | LF | VT | FF | CR |
9517 SO | SI | EM | FS | GS | RS |
9518 US | RI | MW | ST | PM
9521 when NUL | SOH | STX | ETX | EOT |
9522 ENQ | ACK | BEL | DLE | DC1 |
9523 DC2 | DC3 | DC4 | NAK | SYN |
9524 ETB | CAN | SUB | ESC | DEL |
9525 BPH | NBH | NEL | SSA | ESA |
9526 HTS | HTJ | VTS | PLD | PLU |
9527 SS2 | SS3 | DCS | PU1 | PU2 |
9528 STS | CCH | SPA | EPA | SOS |
9529 SCI | CSI | OSC | APC
9533 No_Break_Space .. LC_Y_Diaeresis
9534 =>
9535 -- Special case of soft hyphen in Ada 2005
9539 then
9541 else
9550 -- Width for types derived from Standard.Boolean
9555 else
9559 -- Width for integer types
9570 -- User declared enum type with discard names
9574 -- If range is null, result is zero, that has already
9575 -- been dealt with, so what we need is the power of ten
9576 -- that accomodates the Pos of the largest value, which
9577 -- is the high bound of the range + one for the space.
9586 -- Only remaining possibility is user declared enum type
9587 -- with normal case of Discard_Names not active.
9589 else
9596 -- Only pay attention to in range characters
9600 then
9601 -- For Width case, use decoded name
9607 -- For Wide_[Wide_]Width, use encoded name, and
9608 -- then adjust for the encoding.
9610 else
9613 -- Character literals are always of length 3
9618 -- Otherwise loop to adjust for upper/wide chars
9620 else
9646 -- The following attributes denote functions that cannot be folded
9648 when Attribute_From_Any |
9649 Attribute_To_Any |
9650 Attribute_TypeCode =>
9653 -- The following attributes can never be folded, and furthermore we
9654 -- should not even have entered the case statement for any of these.
9655 -- Note that in some cases, the values have already been folded as
9656 -- a result of the processing in Analyze_Attribute or earlier in
9657 -- this procedure.
9659 when Attribute_Abort_Signal |
9660 Attribute_Access |
9661 Attribute_Address |
9662 Attribute_Address_Size |
9663 Attribute_Asm_Input |
9664 Attribute_Asm_Output |
9665 Attribute_Base |
9666 Attribute_Bit_Order |
9667 Attribute_Bit_Position |
9668 Attribute_Callable |
9669 Attribute_Caller |
9670 Attribute_Class |
9671 Attribute_Code_Address |
9672 Attribute_Compiler_Version |
9673 Attribute_Count |
9674 Attribute_Default_Bit_Order |
9675 Attribute_Default_Scalar_Storage_Order |
9676 Attribute_Deref |
9677 Attribute_Elaborated |
9678 Attribute_Elab_Body |
9679 Attribute_Elab_Spec |
9680 Attribute_Elab_Subp_Body |
9681 Attribute_Enabled |
9682 Attribute_External_Tag |
9683 Attribute_Fast_Math |
9684 Attribute_First_Bit |
9685 Attribute_Img |
9686 Attribute_Input |
9687 Attribute_Last_Bit |
9688 Attribute_Library_Level |
9689 Attribute_Maximum_Alignment |
9690 Attribute_Old |
9691 Attribute_Output |
9692 Attribute_Partition_ID |
9693 Attribute_Pool_Address |
9694 Attribute_Position |
9695 Attribute_Priority |
9696 Attribute_Read |
9697 Attribute_Result |
9698 Attribute_Scalar_Storage_Order |
9699 Attribute_Simple_Storage_Pool |
9700 Attribute_Storage_Pool |
9701 Attribute_Storage_Size |
9702 Attribute_Storage_Unit |
9703 Attribute_Stub_Type |
9704 Attribute_System_Allocator_Alignment |
9705 Attribute_Tag |
9706 Attribute_Target_Name |
9707 Attribute_Terminated |
9708 Attribute_To_Address |
9709 Attribute_Type_Key |
9710 Attribute_UET_Address |
9711 Attribute_Unchecked_Access |
9712 Attribute_Universal_Literal_String |
9713 Attribute_Unrestricted_Access |
9714 Attribute_Valid |
9715 Attribute_Valid_Scalars |
9716 Attribute_Value |
9717 Attribute_Wchar_T_Size |
9718 Attribute_Wide_Value |
9719 Attribute_Wide_Wide_Value |
9720 Attribute_Word_Size |
9721 Attribute_Write =>
9726 -- At the end of the case, one more check. If we did a static evaluation
9727 -- so that the result is now a literal, then set Is_Static_Expression
9728 -- in the constant only if the prefix type is a static subtype. For
9729 -- non-static subtypes, the folding is still OK, but not static.
9731 -- An exception is the GNAT attribute Constrained_Array which is
9732 -- defined to be a static attribute in all cases.
9735 N_Real_Literal,
9736 N_Character_Literal,
9737 N_String_Literal)
9740 then
9743 -- If this is still an attribute reference, then it has not been folded
9744 -- and that means that its expressions are in a non-static context.
9747 Check_Expressions;
9749 -- Note: the else case not covered here are odd cases where the
9750 -- processing has transformed the attribute into something other
9751 -- than a constant. Nothing more to do in such cases.
9753 else
9758 ------------------------------
9759 -- Is_Anonymous_Tagged_Base --
9760 ------------------------------
9762 function Is_Anonymous_Tagged_Base
9765 is
9766 begin
9767 return
9768 Anon = Current_Scope
9773 --------------------------------
9774 -- Name_Implies_Lvalue_Prefix --
9775 --------------------------------
9779 begin
9783 -----------------------
9784 -- Resolve_Attribute --
9785 -----------------------
9799 -- Error, or warning within an instance, if the static accessibility
9800 -- rules of 3.10.2 are violated.
9802 function Declared_Within_Generic_Unit
9805 -- Returns True if Declared_Entity is declared within the declarative
9806 -- region of Generic_Unit; otherwise returns False.
9808 ---------------------------
9809 -- Accessibility_Message --
9810 ---------------------------
9815 begin
9816 -- In an instance, this is a runtime check, but one we
9817 -- know will fail, so generate an appropriate warning.
9821 Error_Msg_F
9830 else
9833 -- Check for case where we have a missing access definition
9836 and then
9838 N_Index_Or_Discriminant_Constraint)
9839 then
9843 loop
9848 Error_Msg_NE
9857 ----------------------------------
9858 -- Declared_Within_Generic_Unit --
9859 ----------------------------------
9861 function Declared_Within_Generic_Unit
9864 is
9867 begin
9873 -- We have to step to the scope of the generic's entity, because
9874 -- otherwise we'll just get back the same generic.
9876 Generic_Encloser :=
9877 Enclosing_Generic_Unit
9884 -- Start of processing for Resolve_Attribute
9886 begin
9887 -- If error during analysis, no point in continuing, except for array
9888 -- types, where we get better recovery by using unconstrained indexes
9889 -- than nothing at all (see Check_Array_Type).
9896 then
9900 -- If attribute was universal type, reset to actual type
9904 then
9908 -- Remaining processing depends on attribute
9912 ------------
9913 -- Access --
9914 ------------
9916 -- For access attributes, if the prefix denotes an entity, it is
9917 -- interpreted as a name, never as a call. It may be overloaded,
9918 -- in which case resolution uses the profile of the context type.
9919 -- Otherwise prefix must be resolved.
9921 when Attribute_Access
9922 | Attribute_Unchecked_Access
9923 | Attribute_Unrestricted_Access =>
9925 Access_Attribute :
9926 begin
9927 -- Note possible modification if we have a variable
9930 declare
9935 -- Skip this for the case of Unrestricted_Access occuring in
9936 -- the context of a Valid check, since this otherwise leads
9937 -- to a missed warning (the Valid check does not really
9938 -- modify!) If this case, Note will be reset to False.
9940 begin
9943 then
9950 then
9961 -- The following comes from a query concerning improper use of
9962 -- universal_access in equality tests involving anonymous access
9963 -- types. Another good reason for 'Ref, but for now disable the
9964 -- test, which breaks several filed tests???
9969 then
9974 -- Case where prefix is an entity name
9978 -- Deal with case where prefix itself is overloaded
9986 -- The prefix is definitely NOT overloaded anymore at
9987 -- this point, so we reset the Is_Overloaded flag to
9988 -- avoid any confusion when reanalyzing the node.
9999 -- If Prefix is a subprogram name, this reference freezes:
10001 -- If it is a type, there is nothing to resolve.
10002 -- If it is an object, complete its resolution.
10006 -- Avoid insertion of freeze actions in spec expression mode
10012 -- Nothing to do if prefix is a type name
10017 -- Otherwise non-overloaded other case, resolve the prefix
10019 else
10023 -- Some further error checks
10032 then
10037 Error_Msg_F
10041 -- An attempt to take 'Access of a function that renames an
10042 -- enumeration literal. Issue a specialized error message.
10047 then
10048 Error_Msg_F
10058 -- Assignments, return statements, components of aggregates,
10059 -- generic instantiations will require convention checks if
10060 -- the type is an access to subprogram. Given that there will
10061 -- also be accessibility checks on those, this is where the
10062 -- checks can eventually be centralized ???
10065 E_Anonymous_Access_Subprogram_Type,
10066 E_Access_Protected_Subprogram_Type,
10067 E_Anonymous_Access_Protected_Subprogram_Type)
10068 then
10069 -- Deal with convention mismatch
10073 then
10074 Error_Msg_FE
10081 then
10082 Error_Msg_FE
10087 else
10088 Check_Subtype_Conformant
10096 Error_Msg_F
10102 -- Check the static accessibility rule of 3.10.2(32).
10103 -- This rule also applies within the private part of an
10104 -- instantiation. This rule does not apply to anonymous
10105 -- access-to-subprogram types in access parameters.
10108 and then not In_Instance_Body
10109 and then
10114 then
10115 Error_Msg_F
10118 -- Check the restriction of 3.10.2(32) that disallows the
10119 -- access attribute within a generic body when the ultimate
10120 -- ancestor of the type of the attribute is declared outside
10121 -- of the generic unit and the subprogram is declared within
10122 -- that generic unit. This includes any such attribute that
10123 -- occurs within the body of a generic unit that is a child
10124 -- of the generic unit where the subprogram is declared.
10126 -- The rule also prohibits applying the attribute when the
10127 -- access type is a generic formal access type (since the
10128 -- level of the actual type is not known). This restriction
10129 -- does not apply when the attribute type is an anonymous
10130 -- access-to-subprogram type. Note that this check was
10131 -- revised by AI-229, because the original Ada 95 rule
10132 -- was too lax. The original rule only applied when the
10133 -- subprogram was declared within the body of the generic,
10134 -- which allowed the possibility of dangling references).
10135 -- The rule was also too strict in some cases, in that it
10136 -- didn't permit the access to be declared in the generic
10137 -- spec, whereas the revised rule does (as long as it's not
10138 -- a formal type).
10140 -- There are a couple of subtleties of the test for applying
10141 -- the check that are worth noting. First, we only apply it
10142 -- when the levels of the subprogram and access type are the
10143 -- same (the case where the subprogram is statically deeper
10144 -- was applied above, and the case where the type is deeper
10145 -- is always safe). Second, we want the check to apply
10146 -- within nested generic bodies and generic child unit
10147 -- bodies, but not to apply to an attribute that appears in
10148 -- the generic unit's specification. This is done by testing
10149 -- that the attribute's innermost enclosing generic body is
10150 -- not the same as the innermost generic body enclosing the
10151 -- generic unit where the subprogram is declared (we don't
10152 -- want the check to apply when the access attribute is in
10153 -- the spec and there's some other generic body enclosing
10154 -- generic). Finally, there's no point applying the check
10155 -- when within an instance, because any violations will have
10156 -- been caught by the compilation of the generic unit.
10158 -- We relax this check in Relaxed_RM_Semantics mode for
10159 -- compatibility with legacy code for use by Ada source
10160 -- code analyzers (e.g. CodePeer).
10163 and then not Relaxed_RM_Semantics
10164 and then not In_Instance
10168 Enclosing_Generic_Body
10173 E_Anonymous_Access_Subprogram_Type
10175 E_Anonymous_Access_Protected_Subprogram_Type
10176 then
10177 -- The attribute type's ultimate ancestor must be
10178 -- declared within the same generic unit as the
10179 -- subprogram is declared (including within another
10180 -- nested generic unit). The error message is
10181 -- specialized to say "ancestor" for the case where the
10182 -- access type is not its own ancestor, since saying
10183 -- simply "access type" would be very confusing.
10185 if not Declared_Within_Generic_Unit
10188 then
10189 Error_Msg_N
10191 N);
10194 Error_Msg_NE
10198 else
10199 Error_Msg_NE
10205 Error_Msg_NE
10210 -- If the ultimate ancestor of the attribute's type is
10211 -- a formal type, then the attribute is illegal because
10212 -- the actual type might be declared at a higher level.
10213 -- The error message is specialized to say "ancestor"
10214 -- for the case where the access type is not its own
10215 -- ancestor, since saying simply "access type" would be
10216 -- very confusing.
10220 Error_Msg_N
10222 N);
10223 else
10224 Error_Msg_N
10232 -- If this is a renaming, an inherited operation, or a
10233 -- subprogram instance, use the original entity. This may make
10234 -- the node type-inconsistent, so this transformation can only
10235 -- be done if the node will not be reanalyzed. In particular,
10236 -- if it is within a default expression, the transformation
10237 -- must be delayed until the default subprogram is created for
10238 -- it, when the enclosing subprogram is frozen.
10243 and then Expander_Active
10244 then
10251 then
10252 -- Protected operation. If operation is overloaded, must
10253 -- disambiguate. Prefix that denotes protected object itself
10254 -- is resolved with its own type.
10258 Error_Msg_F
10265 -- Implement check implied by 3.10.2 (18.1/2) : F.all'access is
10266 -- statically illegal if F is an anonymous access to subprogram.
10271 E_Anonymous_Access_Subprogram_Type
10272 then
10278 -- Use the designated type of the context to disambiguate
10279 -- Note that this was not strictly conformant to Ada 95,
10280 -- but was the implementation adopted by most Ada 95 compilers.
10281 -- The use of the context type to resolve an Access attribute
10282 -- reference is now mandated in AI-235 for Ada 2005.
10284 declare
10288 begin
10299 else
10303 -- X'Access is illegal if X denotes a constant and the access type
10304 -- is access-to-variable. Same for 'Unchecked_Access. The rule
10305 -- does not apply to 'Unrestricted_Access. If the reference is a
10306 -- default-initialized aggregate component for a self-referential
10307 -- type the reference is legal.
10312 and then
10316 = E_Anonymous_Access_Protected_Subprogram_Type
10320 then
10323 then
10324 -- Legality of a self-reference through an access
10325 -- attribute has been verified in Analyze_Access_Attribute.
10338 then
10339 -- Ada 2005 (AI-412): If the (sub)type is a limited view of an
10340 -- imported entity, and the non-limited view is visible, make
10341 -- use of it. If it is an incomplete subtype, use the base type
10342 -- in any case.
10346 then
10355 or else
10359 then
10360 -- Ada 2005 (AI-230): Check the accessibility of anonymous
10361 -- access types for stand-alone objects, record and array
10362 -- components, and return objects. For a component definition
10363 -- the level is the same of the enclosing composite type.
10368 -- Handle cases where Btyp is the anonymous access
10369 -- type of an Ada 2012 stand-alone object.
10372 N_Object_Declaration)
10373 and then
10376 then
10377 -- In an instance, this is a runtime check, but one we know
10378 -- will fail, so generate an appropriate warning. As usual,
10379 -- this kind of warning is an error in SPARK mode.
10383 Error_Msg_F
10392 else
10393 Error_Msg_F
10399 Error_Msg_F
10401 P);
10404 -- Check static matching rule of 3.10.2(27). Nominal subtype
10405 -- of the prefix must statically match the designated type.
10415 -- If the attribute is in the context of an access
10416 -- parameter, then the prefix is allowed to be of
10417 -- the class-wide type (by AI-127).
10422 then
10423 declare
10426 begin
10436 else
10437 Error_Msg_FE
10440 Error_Msg_FE
10448 or else
10451 then
10452 Error_Msg_FE
10454 Error_Msg_FE
10463 then
10464 Apply_Discriminant_Check
10468 -- Ada 2005 (AI-363): Require static matching when designated
10469 -- type has discriminants and a constrained partial view, since
10470 -- in general objects of such types are mutable, so we can't
10471 -- allow the access value to designate a constrained object
10472 -- (because access values must be assumed to designate mutable
10473 -- objects when designated type does not impose a constraint).
10480 and then
10482 or else
10483 not Object_Type_Has_Constrained_Partial_View
10486 then
10489 else
10490 Error_Msg_F
10496 then
10497 declare
10499 begin
10500 Error_Msg_N
10502 Error_Msg_N
10505 Error_Msg_N
10511 -- Check the static accessibility rule of 3.10.2(28). Note that
10512 -- this check is not performed for the case of an anonymous
10513 -- access type, since the access attribute is always legal
10514 -- in such a context.
10518 and then
10520 then
10521 Accessibility_Message;
10527 E_Anonymous_Access_Protected_Subprogram_Type)
10528 then
10531 then
10534 -- Check accessibility of protected object against that of the
10535 -- access type, but only on user code, because the expander
10536 -- creates access references for handlers. If the context is an
10537 -- anonymous_access_to_protected, there are no accessibility
10538 -- checks either. Omit check entirely for Unrestricted_Access.
10544 then
10545 Accessibility_Message;
10548 -- AI05-0225: If the context is not an access to protected
10549 -- function, the prefix must be a variable, given that it may
10550 -- be used subsequently in a protected call.
10555 then
10556 Error_Msg_N
10565 E_Anonymous_Access_Subprogram_Type)
10567 then
10571 -- The context cannot be a pool-specific type, but this is a
10572 -- legality rule, not a resolution rule, so it must be checked
10573 -- separately, after possibly disambiguation (see AI-245).
10577 then
10581 -- The context may be a constrained access type (however ill-
10582 -- advised such subtypes might be) so in order to generate a
10583 -- constraint check when needed set the type of the attribute
10584 -- reference to the base type of the context.
10588 -- Check for incorrect atomic/volatile reference (RM C.6(12))
10593 then
10594 Error_Msg_F
10600 then
10601 Error_Msg_F
10607 -- Check for unrestricted access where expected type is a thin
10608 -- pointer to an unconstrained array.
10613 then
10614 declare
10616 begin
10618 Error_Msg_N
10620 Error_Msg_N
10627 -- Mark that address of entity is taken
10633 -- Deal with possible elaboration check
10636 declare
10644 -- If the access has been taken and the body of the subprogram
10645 -- has not been see yet, indirect calls must be protected with
10646 -- elaboration checks. We have the proper elaboration machinery
10647 -- for subprograms declared in packages, but within a block or
10648 -- a subprogram the body will appear in the same declarative
10649 -- part, and we must insert a check in the eventual body itself
10650 -- using the elaboration flag that we generate now. The check
10651 -- is then inserted when the body is expanded. This processing
10652 -- is not needed for a stand alone expression function because
10653 -- the internally generated spec and body are always inserted
10654 -- as a pair in the same declarative list.
10656 begin
10657 if Expander_Active
10666 N_Expression_Function
10667 then
10668 -- Create elaboration variable for it
10674 -- Insert declaration for flag after subprogram
10675 -- declaration. Note that attribute reference may
10676 -- appear within a nested scope.
10681 Object_Definition =>
10683 Expression =>
10687 -- Taking the 'Access of an expression function freezes its
10688 -- expression (RM 13.14 10.3/3). This does not apply to an
10689 -- expression function that acts as a completion because the
10690 -- generated body is immediately analyzed and the expression
10691 -- is automatically frozen.
10695 then
10696 Subp_Body :=
10699 -- The body has already been analyzed when the expression
10700 -- function acts as a completion.
10705 -- Attribute 'Access may appear within the generated body
10706 -- of the expression function subject to the attribute:
10708 -- function F is (... F'Access ...);
10710 -- If the expression function is on the scope stack, then
10711 -- the body is currently being analyzed. Do not reanalyze
10712 -- it because this will lead to infinite recursion.
10717 -- Analyze the body of the expression function to freeze
10718 -- the expression. This takes care of the case where the
10719 -- 'Access is part of dispatch table initialization and
10720 -- the generated body of the expression function has not
10721 -- been analyzed yet.
10723 else
10731 -------------
10732 -- Address --
10733 -------------
10735 -- Deal with resolving the type for Address attribute, overloading
10736 -- is not permitted here, since there is no context to resolve it.
10741 -- To be safe, assume that if the address of a variable is taken,
10742 -- it may be modified via this address, so note modification.
10750 then
10756 Error_Msg_F
10763 then
10766 then
10771 -- If this is the name of a derived subprogram, or that of a
10772 -- generic actual, the address is that of the original entity.
10777 then
10788 -- Arr (X .. Y)'address is identical to Arr (X)'address,
10789 -- even if the array is packed and the slice itself is not
10790 -- addressable. Transform the prefix into an indexed component.
10792 -- Note that the transformation is safe only if we know that
10793 -- the slice is non-null. That is because a null slice can have
10794 -- an out of bounds index value.
10796 -- Right now, gigi blows up if given 'Address on a slice as a
10797 -- result of some incorrect freeze nodes generated by the front
10798 -- end, and this covers up that bug in one case, but the bug is
10799 -- likely still there in the cases not handled by this code ???
10801 -- It's not clear what 'Address *should* return for a null
10802 -- slice with out of bounds indexes, this might be worth an ARG
10803 -- discussion ???
10805 -- One approach would be to do a length check unconditionally,
10806 -- and then do the transformation below unconditionally, but
10807 -- analyze with checks off, avoiding the problem of the out of
10808 -- bounds index. This approach would interpret the address of
10809 -- an out of bounds null slice as being the address where the
10810 -- array element would be if there was one, which is probably
10811 -- as reasonable an interpretation as any ???
10813 declare
10818 begin
10820 and then
10821 Not_Null_Range
10824 then
10825 Lo :=
10832 then
10835 else
10851 ------------------
10852 -- Body_Version --
10853 ------------------
10855 -- Prefix of Body_Version attribute can be a subprogram name which
10856 -- must not be resolved, since this is not a call.
10861 ------------
10862 -- Caller --
10863 ------------
10865 -- Prefix of Caller attribute is an entry name which must not
10866 -- be resolved, since this is definitely not an entry call.
10871 ------------------
10872 -- Code_Address --
10873 ------------------
10875 -- Shares processing with Address attribute
10877 -----------
10878 -- Count --
10879 -----------
10881 -- If the prefix of the Count attribute is an entry name it must not
10882 -- be resolved, since this is definitely not an entry call. However,
10883 -- if it is an element of an entry family, the index itself may
10884 -- have to be resolved because it can be a general expression.
10889 then
10890 declare
10893 begin
10899 ----------------
10900 -- Elaborated --
10901 ----------------
10903 -- Prefix of the Elaborated attribute is a subprogram name which
10904 -- must not be resolved, since this is definitely not a call. Note
10905 -- that it is a library unit, so it cannot be overloaded here.
10910 -------------
10911 -- Enabled --
10912 -------------
10914 -- Prefix of Enabled attribute is a check name, which must be treated
10915 -- specially and not touched by Resolve.
10920 ----------------
10921 -- Loop_Entry --
10922 ----------------
10924 -- Do not resolve the prefix of Loop_Entry, instead wait until the
10925 -- attribute has been expanded (see Expand_Loop_Entry_Attributes).
10926 -- The delay ensures that any generated checks or temporaries are
10927 -- inserted before the relocated prefix.
10932 --------------------
10933 -- Mechanism_Code --
10934 --------------------
10936 -- Prefix of the Mechanism_Code attribute is a function name
10937 -- which must not be resolved. Should we check for overloaded ???
10942 ------------------
10943 -- Partition_ID --
10944 ------------------
10946 -- Most processing is done in sem_dist, after determining the
10947 -- context type. Node is rewritten as a conversion to a runtime call.
10953 ------------------
10954 -- Pool_Address --
10955 ------------------
10960 -----------
10961 -- Range --
10962 -----------
10964 -- We replace the Range attribute node with a range expression whose
10965 -- bounds are the 'First and 'Last attributes applied to the same
10966 -- prefix. The reason that we do this transformation here instead of
10967 -- in the expander is that it simplifies other parts of the semantic
10968 -- analysis which assume that the Range has been replaced; thus it
10969 -- must be done even when in semantic-only mode (note that the RM
10970 -- specifically mentions this equivalence, we take care that the
10971 -- prefix is only evaluated once).
10974 declare
10979 begin
10982 then
10988 HB :=
10994 LB :=
11000 -- Do not share the dimension indicator, if present. Even
11001 -- though it is a static constant, its source location
11002 -- may be modified when printing expanded code and node
11003 -- sharing will lead to chaos in Sprint.
11010 -- If the original was marked as Must_Not_Freeze (see code
11011 -- in Sem_Ch3.Make_Index), then make sure the rewriting
11012 -- does not freeze either.
11023 -- Preserve Sloc of prefix in the new bounds, so that
11024 -- the posted warning can be removed if we are within
11025 -- unreachable code.
11034 -- Ensure that the expanded range does not have side effects
11039 -- Normally after resolving attribute nodes, Eval_Attribute
11040 -- is called to do any possible static evaluation of the node.
11041 -- However, here since the Range attribute has just been
11042 -- transformed into a range expression it is no longer an
11043 -- attribute node and therefore the call needs to be avoided
11044 -- and is accomplished by simply returning from the procedure.
11049 ------------
11050 -- Result --
11051 ------------
11053 -- We will only come here during the prescan of a spec expression
11054 -- containing a Result attribute. In that case the proper Etype has
11055 -- already been set, and nothing more needs to be done here.
11060 -----------------
11061 -- UET_Address --
11062 -----------------
11064 -- Prefix must not be resolved in this case, since it is not a
11065 -- real entity reference. No action of any kind is require.
11070 ----------------------
11071 -- Unchecked_Access --
11072 ----------------------
11074 -- Processing is shared with Access
11076 -------------------------
11077 -- Unrestricted_Access --
11078 -------------------------
11080 -- Processing is shared with Access
11082 ------------
11083 -- Update --
11084 ------------
11086 -- Resolve aggregate components in component associations
11089 declare
11096 begin
11097 -- Set the Etype of the aggregate to that of the prefix, even
11098 -- though the aggregate may not be a proper representation of a
11099 -- value of the type (missing or duplicated associations, etc.)
11100 -- Complete resolution of the prefix. Note that in Ada 2012 it
11101 -- can be a qualified expression that is e.g. an aggregate.
11106 -- For an array type, resolve expressions with the component
11107 -- type of the array, and apply constraint checks when needed.
11115 -- For scalar array components set Do_Range_Check when
11116 -- needed. Constraint checking on non-scalar components
11117 -- is done in Aggregate_Constraint_Checks, but only if
11118 -- full analysis is enabled. These flags are not set in
11119 -- the front-end in GnatProve mode.
11123 then
11126 then
11129 else
11134 -- The choices in the association are static constants,
11135 -- or static aggregates each of whose components belongs
11136 -- to the proper index type. However, they must also
11137 -- belong to the index subtype (s) of the prefix, which
11138 -- may be a subtype (e.g. given by a slice).
11140 -- Choices may also be identifiers with no staticness
11141 -- requirements, in which case they must resolve to the
11142 -- index type.
11144 declare
11149 begin
11159 else
11178 -- For a record type, use type of each component, which is
11179 -- recorded during analysis.
11181 else
11189 then
11194 then
11204 ---------
11205 -- Val --
11206 ---------
11208 -- Apply range check. Note that we did not do this during the
11209 -- analysis phase, since we wanted Eval_Attribute to have a
11210 -- chance at finding an illegal out of range value.
11214 -- Note that we do our own Eval_Attribute call here rather than
11215 -- use the common one, because we need to do processing after
11216 -- the call, as per above comment.
11220 -- Eval_Attribute may replace the node with a raise CE, or
11221 -- fold it to a constant. Obviously we only apply a scalar
11222 -- range check if this did not happen.
11226 then
11232 -------------
11233 -- Version --
11234 -------------
11236 -- Prefix of Version attribute can be a subprogram name which
11237 -- must not be resolved, since this is not a call.
11242 ----------------------
11243 -- Other Attributes --
11244 ----------------------
11246 -- For other attributes, resolve prefix unless it is a type. If
11247 -- the attribute reference itself is a type name ('Base and 'Class)
11248 -- then this is only legal within a task or protected record.
11255 -- If the attribute reference itself is a type name ('Base,
11256 -- 'Class) then this is only legal within a task or protected
11257 -- record. What is this all about ???
11262 then
11264 else
11265 Error_Msg_N
11270 -- For attributes whose argument may be a string, complete
11271 -- resolution of argument now. This avoids premature expansion
11272 -- (and the creation of transient scopes) before the attribute
11273 -- reference is resolved.
11288 -- If the prefix of the attribute is a class-wide type then it
11289 -- will be expanded into a dispatching call to a predefined
11290 -- primitive. Therefore we must check for potential violation
11291 -- of such restriction.
11298 -- Normally the Freezing is done by Resolve but sometimes the Prefix
11299 -- is not resolved, in which case the freezing must be done now.
11301 -- For an elaboration check on a subprogram, we do not freeze its type.
11302 -- It may be declared in an unrelated scope, in particular in the case
11303 -- of a generic function whose type may remain unelaborated.
11308 else
11312 -- Finally perform static evaluation on the attribute reference
11318 ------------------------
11319 -- Set_Boolean_Result --
11320 ------------------------
11324 begin
11327 else
11332 --------------------------------
11333 -- Stream_Attribute_Available --
11334 --------------------------------
11336 function Stream_Attribute_Available
11340 is
11343 -- Start of processing for Stream_Attribute_Available
11345 begin
11346 -- We need some comments in this body ???
11360 then
11367 then
11371 -- In Ada 2005, Input can invoke Read, and Output can invoke Write
11376 then
11382 then
11386 -- Case of Read and Write: check for attribute definition clause that
11387 -- applies to an ancestor type.
11399 -- In Ada 95 mode, also consider a non-visible definition
11401 declare
11403 begin
11405 and then Stream_Attribute_Available