1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2023, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Aspects
; use Aspects
;
27 with Atree
; use Atree
;
28 with Checks
; use Checks
;
29 with Debug
; use Debug
;
30 with Einfo
; use Einfo
;
31 with Einfo
.Entities
; use Einfo
.Entities
;
32 with Einfo
.Utils
; use Einfo
.Utils
;
33 with Errout
; use Errout
;
34 with Expander
; use Expander
;
35 with Exp_Ch6
; use Exp_Ch6
;
36 with Exp_Tss
; use Exp_Tss
;
37 with Exp_Util
; use Exp_Util
;
38 with Freeze
; use Freeze
;
39 with Ghost
; use Ghost
;
41 with Lib
.Xref
; use Lib
.Xref
;
42 with Namet
; use Namet
;
43 with Nlists
; use Nlists
;
44 with Nmake
; use Nmake
;
47 with Sem_Aux
; use Sem_Aux
;
48 with Sem_Case
; use Sem_Case
;
49 with Sem_Ch3
; use Sem_Ch3
;
50 with Sem_Ch6
; use Sem_Ch6
;
51 with Sem_Ch8
; use Sem_Ch8
;
52 with Sem_Dim
; use Sem_Dim
;
53 with Sem_Disp
; use Sem_Disp
;
54 with Sem_Elab
; use Sem_Elab
;
55 with Sem_Eval
; use Sem_Eval
;
56 with Sem_Res
; use Sem_Res
;
57 with Sem_Type
; use Sem_Type
;
58 with Sem_Util
; use Sem_Util
;
59 with Sem_Warn
; use Sem_Warn
;
60 with Snames
; use Snames
;
61 with Stand
; use Stand
;
62 with Sinfo
; use Sinfo
;
63 with Sinfo
.Nodes
; use Sinfo
.Nodes
;
64 with Sinfo
.Utils
; use Sinfo
.Utils
;
65 with Targparm
; use Targparm
;
66 with Tbuild
; use Tbuild
;
67 with Ttypes
; use Ttypes
;
68 with Uintp
; use Uintp
;
69 with Warnsw
; use Warnsw
;
71 package body Sem_Ch5
is
73 Current_Assignment
: Node_Id
:= Empty
;
74 -- This variable holds the node for an assignment that contains target
75 -- names. The corresponding flag has been set by the parser, and when
76 -- set the analysis of the RHS must be done with all expansion disabled,
77 -- because the assignment is reanalyzed after expansion has replaced all
78 -- occurrences of the target name appropriately.
80 Unblocked_Exit_Count
: Nat
:= 0;
81 -- This variable is used when processing if statements, case statements,
82 -- and block statements. It counts the number of exit points that are not
83 -- blocked by unconditional transfer instructions: for IF and CASE, these
84 -- are the branches of the conditional; for a block, they are the statement
85 -- sequence of the block, and the statement sequences of any exception
86 -- handlers that are part of the block. When processing is complete, if
87 -- this count is zero, it means that control cannot fall through the IF,
88 -- CASE or block statement. This is used for the generation of warning
89 -- messages. This variable is recursively saved on entry to processing the
90 -- construct, and restored on exit.
92 function Has_Sec_Stack_Call
(N
: Node_Id
) return Boolean;
93 -- N is the node for an arbitrary construct. This function searches the
94 -- construct N to see if any expressions within it contain function
95 -- calls that use the secondary stack, returning True if any such call
96 -- is found, and False otherwise.
98 procedure Preanalyze_Range
(R_Copy
: Node_Id
);
99 -- Determine expected type of range or domain of iteration of Ada 2012
100 -- loop by analyzing separate copy. Do the analysis and resolution of the
101 -- copy of the bound(s) with expansion disabled, to prevent the generation
102 -- of finalization actions. This prevents memory leaks when the bounds
103 -- contain calls to functions returning controlled arrays or when the
104 -- domain of iteration is a container.
106 ------------------------
107 -- Analyze_Assignment --
108 ------------------------
110 -- WARNING: This routine manages Ghost regions. Return statements must be
111 -- replaced by gotos which jump to the end of the routine and restore the
114 procedure Analyze_Assignment
(N
: Node_Id
) is
115 Lhs
: constant Node_Id
:= Name
(N
);
116 Rhs
: Node_Id
:= Expression
(N
);
118 procedure Diagnose_Non_Variable_Lhs
(N
: Node_Id
);
119 -- N is the node for the left hand side of an assignment, and it is not
120 -- a variable. This routine issues an appropriate diagnostic.
122 function Is_Protected_Part_Of_Constituent
123 (Nod
: Node_Id
) return Boolean;
124 -- Determine whether arbitrary node Nod denotes a Part_Of constituent of
125 -- a single protected type.
128 -- This is called to kill current value settings of a simple variable
129 -- on the left hand side. We call it if we find any error in analyzing
130 -- the assignment, and at the end of processing before setting any new
131 -- current values in place.
133 procedure Set_Assignment_Type
135 Opnd_Type
: in out Entity_Id
);
136 -- Opnd is either the Lhs or Rhs of the assignment, and Opnd_Type is the
137 -- nominal subtype. This procedure is used to deal with cases where the
138 -- nominal subtype must be replaced by the actual subtype.
140 procedure Transform_BIP_Assignment
(Typ
: Entity_Id
);
141 function Should_Transform_BIP_Assignment
142 (Typ
: Entity_Id
) return Boolean;
143 -- If the right-hand side of an assignment statement is a build-in-place
144 -- call we cannot build in place, so we insert a temp initialized with
145 -- the call, and transform the assignment statement to copy the temp.
146 -- Transform_BIP_Assignment does the transformation, and
147 -- Should_Transform_BIP_Assignment determines whether we should.
148 -- The same goes for qualified expressions and conversions whose
149 -- operand is such a call.
151 -- This is only for nonlimited types; assignment statements are illegal
152 -- for limited types, but are generated internally for aggregates and
153 -- init procs. These limited-type are not really assignment statements
154 -- -- conceptually, they are initializations, so should not be
157 -- Similarly, for nonlimited types, aggregates and init procs generate
158 -- assignment statements that are really initializations. These are
159 -- marked No_Ctrl_Actions.
161 function Within_Function
return Boolean;
162 -- Determine whether the current scope is a function or appears within
165 -------------------------------
166 -- Diagnose_Non_Variable_Lhs --
167 -------------------------------
169 procedure Diagnose_Non_Variable_Lhs
(N
: Node_Id
) is
171 -- Not worth posting another error if left hand side already flagged
172 -- as being illegal in some respect.
174 if Error_Posted
(N
) then
177 -- Some special bad cases of entity names
179 elsif Is_Entity_Name
(N
) then
181 Ent
: constant Entity_Id
:= Entity
(N
);
184 if Ekind
(Ent
) = E_Loop_Parameter
185 or else Is_Loop_Parameter
(Ent
)
187 Error_Msg_N
("assignment to loop parameter not allowed", N
);
190 elsif Ekind
(Ent
) = E_In_Parameter
then
192 ("assignment to IN mode parameter not allowed", N
);
195 -- Renamings of protected private components are turned into
196 -- constants when compiling a protected function. In the case
197 -- of single protected types, the private component appears
200 elsif (Is_Prival
(Ent
) and then Within_Function
)
201 or else Is_Protected_Component
(Ent
)
204 ("protected function cannot modify its protected object",
210 -- For indexed components, test prefix if it is in array. We do not
211 -- want to recurse for cases where the prefix is a pointer, since we
212 -- may get a message confusing the pointer and what it references.
214 elsif Nkind
(N
) = N_Indexed_Component
215 and then Is_Array_Type
(Etype
(Prefix
(N
)))
217 Diagnose_Non_Variable_Lhs
(Prefix
(N
));
220 -- Another special case for assignment to discriminant
222 elsif Nkind
(N
) = N_Selected_Component
then
223 if Present
(Entity
(Selector_Name
(N
)))
224 and then Ekind
(Entity
(Selector_Name
(N
))) = E_Discriminant
226 Error_Msg_N
("assignment to discriminant not allowed", N
);
229 -- For selection from record, diagnose prefix, but note that again
230 -- we only do this for a record, not e.g. for a pointer.
232 elsif Is_Record_Type
(Etype
(Prefix
(N
))) then
233 Diagnose_Non_Variable_Lhs
(Prefix
(N
));
238 -- If we fall through, we have no special message to issue
240 Error_Msg_N
("left hand side of assignment must be a variable", N
);
241 end Diagnose_Non_Variable_Lhs
;
243 --------------------------------------
244 -- Is_Protected_Part_Of_Constituent --
245 --------------------------------------
247 function Is_Protected_Part_Of_Constituent
248 (Nod
: Node_Id
) return Boolean
250 Encap_Id
: Entity_Id
;
254 -- Abstract states and variables may act as Part_Of constituents of
255 -- single protected types, however only variables can be modified by
258 if Is_Entity_Name
(Nod
) then
259 Var_Id
:= Entity
(Nod
);
261 if Present
(Var_Id
) and then Ekind
(Var_Id
) = E_Variable
then
262 Encap_Id
:= Encapsulating_State
(Var_Id
);
264 -- To qualify, the node must denote a reference to a variable
265 -- whose encapsulating state is a single protected object.
269 and then Is_Single_Protected_Object
(Encap_Id
);
274 end Is_Protected_Part_Of_Constituent
;
280 procedure Kill_Lhs
is
282 if Is_Entity_Name
(Lhs
) then
284 Ent
: constant Entity_Id
:= Entity
(Lhs
);
286 if Present
(Ent
) then
287 Kill_Current_Values
(Ent
);
293 -------------------------
294 -- Set_Assignment_Type --
295 -------------------------
297 procedure Set_Assignment_Type
299 Opnd_Type
: in out Entity_Id
)
304 Require_Entity
(Opnd
);
306 -- If the assignment operand is an in-out or out parameter, then we
307 -- get the actual subtype (needed for the unconstrained case). If the
308 -- operand is the actual in an entry declaration, then within the
309 -- accept statement it is replaced with a local renaming, which may
310 -- also have an actual subtype. Likewise for a return object that
311 -- lives on the secondary stack.
313 if Is_Entity_Name
(Opnd
)
314 and then (Ekind
(Entity
(Opnd
)) in E_Out_Parameter
316 | E_Generic_In_Out_Parameter
318 (Ekind
(Entity
(Opnd
)) = E_Variable
319 and then Nkind
(Parent
(Entity
(Opnd
))) =
320 N_Object_Renaming_Declaration
321 and then Nkind
(Parent
(Parent
(Entity
(Opnd
)))) =
323 or else Is_Secondary_Stack_Return_Object
(Entity
(Opnd
)))
325 Opnd_Type
:= Get_Actual_Subtype
(Opnd
);
327 -- If assignment operand is a component reference, then we get the
328 -- actual subtype of the component for the unconstrained case.
330 elsif Nkind
(Opnd
) in N_Selected_Component | N_Explicit_Dereference
331 and then not Is_Unchecked_Union
(Opnd_Type
)
333 Decl
:= Build_Actual_Subtype_Of_Component
(Opnd_Type
, Opnd
);
335 if Present
(Decl
) then
336 Insert_Action
(N
, Decl
);
337 Mark_Rewrite_Insertion
(Decl
);
339 Opnd_Type
:= Defining_Identifier
(Decl
);
340 Set_Etype
(Opnd
, Opnd_Type
);
341 Freeze_Itype
(Opnd_Type
, N
);
343 elsif Is_Constrained
(Etype
(Opnd
)) then
344 Opnd_Type
:= Etype
(Opnd
);
347 -- For slice, use the constrained subtype created for the slice
349 elsif Nkind
(Opnd
) = N_Slice
then
350 Opnd_Type
:= Etype
(Opnd
);
352 end Set_Assignment_Type
;
354 -------------------------------------
355 -- Should_Transform_BIP_Assignment --
356 -------------------------------------
358 function Should_Transform_BIP_Assignment
359 (Typ
: Entity_Id
) return Boolean
363 and then not Is_Limited_View
(Typ
)
364 and then Is_Build_In_Place_Result_Type
(Typ
)
365 and then not No_Ctrl_Actions
(N
)
367 -- This function is called early, before name resolution is
368 -- complete, so we have to deal with things that might turn into
369 -- function calls later. N_Function_Call and N_Op nodes are the
370 -- obvious case. An N_Identifier or N_Expanded_Name is a
371 -- parameterless function call if it denotes a function.
372 -- Finally, an attribute reference can be a function call.
375 Unqual_Rhs
: constant Node_Id
:= Unqual_Conv
(Rhs
);
377 case Nkind
(Unqual_Rhs
) is
387 Ekind
(Entity
(Unqual_Rhs
)) in E_Function | E_Operator
;
389 -- T'Input will turn into a call whose result type is T
391 when N_Attribute_Reference
=>
392 return Attribute_Name
(Unqual_Rhs
) = Name_Input
;
401 end Should_Transform_BIP_Assignment
;
403 ------------------------------
404 -- Transform_BIP_Assignment --
405 ------------------------------
407 procedure Transform_BIP_Assignment
(Typ
: Entity_Id
) is
409 -- Tranform "X : [constant] T := F (...);" into:
411 -- Temp : constant T := F (...);
414 Loc
: constant Source_Ptr
:= Sloc
(N
);
415 Def_Id
: constant Entity_Id
:= Make_Temporary
(Loc
, 'Y', Rhs
);
416 Obj_Decl
: constant Node_Id
:=
417 Make_Object_Declaration
(Loc
,
418 Defining_Identifier
=> Def_Id
,
419 Constant_Present
=> True,
420 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
),
422 Has_Init_Expression
=> True);
425 Set_Etype
(Def_Id
, Typ
);
426 Set_Expression
(N
, New_Occurrence_Of
(Def_Id
, Loc
));
428 -- At this point, Rhs is no longer equal to Expression (N), so:
430 Rhs
:= Expression
(N
);
432 Insert_Action
(N
, Obj_Decl
);
433 end Transform_BIP_Assignment
;
435 ---------------------
436 -- Within_Function --
437 ---------------------
439 function Within_Function
return Boolean is
440 Scop_Id
: constant Entity_Id
:= Current_Scope
;
443 if Ekind
(Scop_Id
) = E_Function
then
446 elsif Ekind
(Enclosing_Dynamic_Scope
(Scop_Id
)) = E_Function
then
455 Saved_GM
: constant Ghost_Mode_Type
:= Ghost_Mode
;
456 Saved_IGR
: constant Node_Id
:= Ignored_Ghost_Region
;
457 -- Save the Ghost-related attributes to restore on exit
462 Save_Full_Analysis
: Boolean := False;
463 -- Force initialization to facilitate static analysis
465 -- Start of processing for Analyze_Assignment
468 Mark_Coextensions
(N
, Rhs
);
470 -- Preserve relevant elaboration-related attributes of the context which
471 -- are no longer available or very expensive to recompute once analysis,
472 -- resolution, and expansion are over.
474 Mark_Elaboration_Attributes
479 -- An assignment statement is Ghost when the left hand side denotes a
480 -- Ghost entity. Set the mode now to ensure that any nodes generated
481 -- during analysis and expansion are properly marked as Ghost.
483 Mark_And_Set_Ghost_Assignment
(N
);
485 if Has_Target_Names
(N
) then
486 pragma Assert
(No
(Current_Assignment
));
487 Current_Assignment
:= N
;
488 Expander_Mode_Save_And_Set
(False);
489 Save_Full_Analysis
:= Full_Analysis
;
490 Full_Analysis
:= False;
496 -- Ensure that we never do an assignment on a variable marked as
497 -- Is_Safe_To_Reevaluate.
500 (not Is_Entity_Name
(Lhs
)
501 or else Ekind
(Entity
(Lhs
)) /= E_Variable
502 or else not Is_Safe_To_Reevaluate
(Entity
(Lhs
)));
504 -- Start type analysis for assignment
508 -- In the most general case, both Lhs and Rhs can be overloaded, and we
509 -- must compute the intersection of the possible types on each side.
511 if Is_Overloaded
(Lhs
) then
518 Get_First_Interp
(Lhs
, I
, It
);
520 while Present
(It
.Typ
) loop
522 -- An indexed component with generalized indexing is always
523 -- overloaded with the corresponding dereference. Discard the
524 -- interpretation that yields a reference type, which is not
527 if Nkind
(Lhs
) = N_Indexed_Component
528 and then Present
(Generalized_Indexing
(Lhs
))
529 and then Has_Implicit_Dereference
(It
.Typ
)
533 -- This may be a call to a parameterless function through an
534 -- implicit dereference, so discard interpretation as well.
536 elsif Is_Entity_Name
(Lhs
)
537 and then Has_Implicit_Dereference
(It
.Typ
)
541 elsif Has_Compatible_Type
(Rhs
, It
.Typ
) then
542 if T1
= Any_Type
then
545 -- An explicit dereference is overloaded if the prefix
546 -- is. Try to remove the ambiguity on the prefix, the
547 -- error will be posted there if the ambiguity is real.
549 if Nkind
(Lhs
) = N_Explicit_Dereference
then
552 PI1
: Interp_Index
:= 0;
558 Get_First_Interp
(Prefix
(Lhs
), PI
, PIt
);
560 while Present
(PIt
.Typ
) loop
561 if Is_Access_Type
(PIt
.Typ
)
562 and then Has_Compatible_Type
563 (Rhs
, Designated_Type
(PIt
.Typ
))
567 Disambiguate
(Prefix
(Lhs
),
570 if PIt
= No_Interp
then
572 ("ambiguous left-hand side in "
573 & "assignment", Lhs
);
576 Resolve
(Prefix
(Lhs
), PIt
.Typ
);
586 Get_Next_Interp
(PI
, PIt
);
592 ("ambiguous left-hand side in assignment", Lhs
);
598 Get_Next_Interp
(I
, It
);
602 if T1
= Any_Type
then
604 ("no valid types for left-hand side for assignment", Lhs
);
610 -- Deal with build-in-place calls for nonlimited types. We don't do this
611 -- later, because resolving the rhs tranforms it incorrectly for build-
614 if Should_Transform_BIP_Assignment
(Typ
=> T1
) then
616 -- In certain cases involving user-defined concatenation operators,
617 -- we need to resolve the right-hand side before transforming the
620 case Nkind
(Unqual_Conv
(Rhs
)) is
621 when N_Function_Call
=>
624 First
(Parameter_Associations
(Unqual_Conv
(Rhs
)));
625 Actual_Exp
: Node_Id
;
628 while Present
(Actual
) loop
629 if Nkind
(Actual
) = N_Parameter_Association
then
630 Actual_Exp
:= Explicit_Actual_Parameter
(Actual
);
632 Actual_Exp
:= Actual
;
635 if Nkind
(Actual_Exp
) = N_Op_Concat
then
644 when N_Attribute_Reference
655 Transform_BIP_Assignment
(Typ
=> T1
);
658 pragma Assert
(not Should_Transform_BIP_Assignment
(Typ
=> T1
));
660 -- The resulting assignment type is T1, so now we will resolve the left
661 -- hand side of the assignment using this determined type.
665 -- Cases where Lhs is not a variable. In an instance or an inlined body
666 -- no need for further check because assignment was legal in template.
668 if In_Inlined_Body
then
671 elsif not Is_Variable
(Lhs
) then
673 -- Ada 2005 (AI-327): Check assignment to the attribute Priority of a
681 if Ada_Version
>= Ada_2005
then
683 -- Handle chains of renamings
686 while Nkind
(Ent
) in N_Has_Entity
687 and then Present
(Entity
(Ent
))
688 and then Is_Object
(Entity
(Ent
))
689 and then Present
(Renamed_Object
(Entity
(Ent
)))
691 Ent
:= Renamed_Object
(Entity
(Ent
));
694 if (Nkind
(Ent
) = N_Attribute_Reference
695 and then Attribute_Name
(Ent
) = Name_Priority
)
697 -- Renamings of the attribute Priority applied to protected
698 -- objects have been previously expanded into calls to the
699 -- Get_Ceiling run-time subprogram.
701 or else Is_Expanded_Priority_Attribute
(Ent
)
703 -- The enclosing subprogram cannot be a protected function
706 while not (Is_Subprogram
(S
)
707 and then Convention
(S
) = Convention_Protected
)
708 and then S
/= Standard_Standard
713 if Ekind
(S
) = E_Function
714 and then Convention
(S
) = Convention_Protected
717 ("protected function cannot modify its protected " &
722 -- Changes of the ceiling priority of the protected object
723 -- are only effective if the Ceiling_Locking policy is in
724 -- effect (AARM D.5.2 (5/2)).
726 if Locking_Policy
/= 'C' then
728 ("assignment to the attribute PRIORITY has no effect??",
731 ("\since no Locking_Policy has been specified??", Lhs
);
739 Diagnose_Non_Variable_Lhs
(Lhs
);
742 -- Error of assigning to limited type. We do however allow this in
743 -- certain cases where the front end generates the assignments.
745 elsif Is_Limited_Type
(T1
)
746 and then not Assignment_OK
(Lhs
)
747 and then not Assignment_OK
(Original_Node
(Lhs
))
749 -- CPP constructors can only be called in declarations
751 if Is_CPP_Constructor_Call
(Rhs
) then
752 Error_Msg_N
("invalid use of 'C'P'P constructor", Rhs
);
755 ("left hand of assignment must not be limited type", Lhs
);
756 Explain_Limited_Type
(T1
, Lhs
);
761 -- A class-wide type may be a limited view. This illegal case is not
762 -- caught by previous checks.
764 elsif Ekind
(T1
) = E_Class_Wide_Type
and then From_Limited_With
(T1
) then
765 Error_Msg_NE
("invalid use of limited view of&", Lhs
, T1
);
768 -- Enforce RM 3.9.3 (8): the target of an assignment operation cannot be
769 -- abstract. This is only checked when the assignment Comes_From_Source,
770 -- because in some cases the expander generates such assignments (such
771 -- in the _assign operation for an abstract type).
773 elsif Is_Abstract_Type
(T1
) and then Comes_From_Source
(N
) then
775 ("target of assignment operation must not be abstract", Lhs
);
778 -- Variables which are Part_Of constituents of single protected types
779 -- behave in similar fashion to protected components. Such variables
780 -- cannot be modified by protected functions.
782 if Is_Protected_Part_Of_Constituent
(Lhs
) and then Within_Function
then
784 ("protected function cannot modify its protected object", Lhs
);
787 -- Resolution may have updated the subtype, in case the left-hand side
788 -- is a private protected component. Use the correct subtype to avoid
789 -- scoping issues in the back-end.
793 -- Ada 2005 (AI-50217, AI-326): Check wrong dereference of incomplete
794 -- type. For example:
798 -- type Acc is access P.T;
801 -- with Pkg; use Acc;
802 -- procedure Example is
805 -- A.all := B.all; -- ERROR
808 if Nkind
(Lhs
) = N_Explicit_Dereference
809 and then Ekind
(T1
) = E_Incomplete_Type
811 Error_Msg_N
("invalid use of incomplete type", Lhs
);
816 -- Now we can complete the resolution of the right hand side
818 Set_Assignment_Type
(Lhs
, T1
);
820 -- If the target of the assignment is an entity of a mutable type and
821 -- the expression is a conditional expression, its alternatives can be
822 -- of different subtypes of the nominal type of the LHS, so they must be
823 -- resolved with the base type, given that their subtype may differ from
824 -- that of the target mutable object.
826 if Is_Entity_Name
(Lhs
)
827 and then Is_Assignable
(Entity
(Lhs
))
828 and then Is_Composite_Type
(T1
)
829 and then not Is_Constrained
(Etype
(Entity
(Lhs
)))
830 and then Nkind
(Rhs
) in N_If_Expression | N_Case_Expression
832 Resolve
(Rhs
, Base_Type
(T1
));
838 -- This is the point at which we check for an unset reference
840 Check_Unset_Reference
(Rhs
);
841 Check_Unprotected_Access
(Lhs
, Rhs
);
843 -- Remaining steps are skipped if Rhs was syntactically in error
852 if not Covers
(T1
, T2
) then
853 Wrong_Type
(Rhs
, Etype
(Lhs
));
858 -- Ada 2005 (AI-326): In case of explicit dereference of incomplete
859 -- types, use the non-limited view if available
861 if Nkind
(Rhs
) = N_Explicit_Dereference
862 and then Is_Tagged_Type
(T2
)
863 and then Has_Non_Limited_View
(T2
)
865 T2
:= Non_Limited_View
(T2
);
868 Set_Assignment_Type
(Rhs
, T2
);
870 if Total_Errors_Detected
/= 0 then
880 if T1
= Any_Type
or else T2
= Any_Type
then
885 -- If the rhs is class-wide or dynamically tagged, then require the lhs
886 -- to be class-wide. The case where the rhs is a dynamically tagged call
887 -- to a dispatching operation with a controlling access result is
888 -- excluded from this check, since the target has an access type (and
889 -- no tag propagation occurs in that case).
891 if (Is_Class_Wide_Type
(T2
)
892 or else (Is_Dynamically_Tagged
(Rhs
)
893 and then not Is_Access_Type
(T1
)))
894 and then not Is_Class_Wide_Type
(T1
)
896 Error_Msg_N
("dynamically tagged expression not allowed!", Rhs
);
898 elsif Is_Class_Wide_Type
(T1
)
899 and then not Is_Class_Wide_Type
(T2
)
900 and then not Is_Tag_Indeterminate
(Rhs
)
901 and then not Is_Dynamically_Tagged
(Rhs
)
903 Error_Msg_N
("dynamically tagged expression required!", Rhs
);
906 -- Propagate the tag from a class-wide target to the rhs when the rhs
907 -- is a tag-indeterminate call.
909 if Is_Tag_Indeterminate
(Rhs
) then
910 if Is_Class_Wide_Type
(T1
) then
911 Propagate_Tag
(Lhs
, Rhs
);
913 elsif Nkind
(Rhs
) = N_Function_Call
914 and then Is_Entity_Name
(Name
(Rhs
))
915 and then Is_Abstract_Subprogram
(Entity
(Name
(Rhs
)))
918 ("call to abstract function must be dispatching", Name
(Rhs
));
920 elsif Nkind
(Rhs
) = N_Qualified_Expression
921 and then Nkind
(Expression
(Rhs
)) = N_Function_Call
922 and then Is_Entity_Name
(Name
(Expression
(Rhs
)))
924 Is_Abstract_Subprogram
(Entity
(Name
(Expression
(Rhs
))))
927 ("call to abstract function must be dispatching",
928 Name
(Expression
(Rhs
)));
932 -- Ada 2005 (AI-385): When the lhs type is an anonymous access type,
933 -- apply an implicit conversion of the rhs to that type to force
934 -- appropriate static and run-time accessibility checks. This applies
935 -- as well to anonymous access-to-subprogram types that are component
936 -- subtypes or formal parameters.
938 if Ada_Version
>= Ada_2005
and then Is_Access_Type
(T1
) then
939 if Is_Local_Anonymous_Access
(T1
)
940 or else Ekind
(T2
) = E_Anonymous_Access_Subprogram_Type
942 -- Handle assignment to an Ada 2012 stand-alone object
943 -- of an anonymous access type.
945 or else (Ekind
(T1
) = E_Anonymous_Access_Type
946 and then Nkind
(Associated_Node_For_Itype
(T1
)) =
947 N_Object_Declaration
)
950 Rewrite
(Rhs
, Convert_To
(T1
, Relocate_Node
(Rhs
)));
951 Analyze_And_Resolve
(Rhs
, T1
);
955 -- Ada 2005 (AI-231): Assignment to not null variable
957 if Ada_Version
>= Ada_2005
958 and then Can_Never_Be_Null
(T1
)
959 and then not Assignment_OK
(Lhs
)
961 -- Case where we know the right hand side is null
963 if Known_Null
(Rhs
) then
964 Apply_Compile_Time_Constraint_Error
967 "(Ada 2005) NULL not allowed in null-excluding objects??",
968 Reason
=> CE_Null_Not_Allowed
);
970 -- We still mark this as a possible modification, that's necessary
971 -- to reset Is_True_Constant, and desirable for xref purposes.
973 Note_Possible_Modification
(Lhs
, Sure
=> True);
976 -- If we know the right hand side is non-null, then we convert to the
977 -- target type, since we don't need a run time check in that case.
979 elsif not Can_Never_Be_Null
(T2
) then
980 Rewrite
(Rhs
, Convert_To
(T1
, Relocate_Node
(Rhs
)));
981 Analyze_And_Resolve
(Rhs
, T1
);
985 if Is_Scalar_Type
(T1
) then
988 function Omit_Range_Check_For_Streaming
return Boolean;
989 -- Return True if this assignment statement is the expansion of
990 -- a Some_Scalar_Type'Read procedure call such that all conditions
991 -- of 13.3.2(35)'s "no check is made" rule are met.
993 ------------------------------------
994 -- Omit_Range_Check_For_Streaming --
995 ------------------------------------
997 function Omit_Range_Check_For_Streaming
return Boolean is
999 -- Have we got an implicitly generated assignment to a
1000 -- component of a composite object? If not, return False.
1002 if Comes_From_Source
(N
)
1003 or else Serious_Errors_Detected
> 0
1005 not in N_Selected_Component | N_Indexed_Component
1011 Pref
: constant Node_Id
:= Prefix
(Lhs
);
1013 -- Are we in the implicitly-defined Read subprogram
1014 -- for a composite type, reading the value of a scalar
1015 -- component from the stream? If not, return False.
1017 if Nkind
(Pref
) /= N_Identifier
1018 or else not Is_TSS
(Scope
(Entity
(Pref
)), TSS_Stream_Read
)
1023 -- Return False if Default_Value or Default_Component_Value
1026 if Has_Default_Aspect
(Etype
(Lhs
))
1027 or else Has_Default_Aspect
(Etype
(Pref
))
1031 -- Are we assigning to a record component (as opposed to
1032 -- an array component)?
1034 elsif Nkind
(Lhs
) = N_Selected_Component
then
1036 -- Are we assigning to a nondiscriminant component
1037 -- that lacks a default initial value expression?
1038 -- If so, return True.
1041 Comp_Id
: constant Entity_Id
:=
1042 Original_Record_Component
1043 (Entity
(Selector_Name
(Lhs
)));
1045 if Ekind
(Comp_Id
) = E_Component
1046 and then Nkind
(Parent
(Comp_Id
))
1047 = N_Component_Declaration
1048 and then No
(Expression
(Parent
(Comp_Id
)))
1055 -- We are assigning to a component of an array
1056 -- (and we tested for both Default_Value and
1057 -- Default_Component_Value above), so return True.
1060 pragma Assert
(Nkind
(Lhs
) = N_Indexed_Component
);
1064 end Omit_Range_Check_For_Streaming
;
1067 if not Omit_Range_Check_For_Streaming
then
1068 Apply_Scalar_Range_Check
(Rhs
, Etype
(Lhs
));
1072 -- For array types, verify that lengths match. If the right hand side
1073 -- is a function call that has been inlined, the assignment has been
1074 -- rewritten as a block, and the constraint check will be applied to the
1075 -- assignment within the block.
1077 elsif Is_Array_Type
(T1
)
1078 and then (Nkind
(Rhs
) /= N_Type_Conversion
1079 or else Is_Constrained
(Etype
(Rhs
)))
1080 and then (Nkind
(Rhs
) /= N_Function_Call
1081 or else Nkind
(N
) /= N_Block_Statement
)
1083 -- Assignment verifies that the length of the Lhs and Rhs are equal,
1084 -- but of course the indexes do not have to match. If the right-hand
1085 -- side is a type conversion to an unconstrained type, a length check
1086 -- is performed on the expression itself during expansion. In rare
1087 -- cases, the redundant length check is computed on an index type
1088 -- with a different representation, triggering incorrect code in the
1091 Apply_Length_Check_On_Assignment
(Rhs
, Etype
(Lhs
), Lhs
);
1094 -- Discriminant checks are applied in the course of expansion
1099 -- Note: modifications of the Lhs may only be recorded after
1100 -- checks have been applied.
1102 Note_Possible_Modification
(Lhs
, Sure
=> True);
1104 -- ??? a real accessibility check is needed when ???
1106 -- Post warning for redundant assignment or variable to itself
1108 if Warn_On_Redundant_Constructs
1110 -- We only warn for source constructs
1112 and then Comes_From_Source
(N
)
1114 -- Where the object is the same on both sides
1116 and then Same_Object
(Lhs
, Rhs
)
1118 -- But exclude the case where the right side was an operation that
1119 -- got rewritten (e.g. JUNK + K, where K was known to be zero). We
1120 -- don't want to warn in such a case, since it is reasonable to write
1121 -- such expressions especially when K is defined symbolically in some
1124 and then Nkind
(Original_Node
(Rhs
)) not in N_Op
1126 if Nkind
(Lhs
) in N_Has_Entity
then
1127 Error_Msg_NE
-- CODEFIX
1128 ("?r?useless assignment of & to itself!", N
, Entity
(Lhs
));
1130 Error_Msg_N
-- CODEFIX
1131 ("?r?useless assignment of object to itself!", N
);
1135 -- Check for non-allowed composite assignment
1137 if not Support_Composite_Assign_On_Target
1138 and then (Is_Array_Type
(T1
) or else Is_Record_Type
(T1
))
1139 and then (not Has_Size_Clause
(T1
)
1140 or else Esize
(T1
) > Ttypes
.System_Max_Integer_Size
)
1142 Error_Msg_CRT
("composite assignment", N
);
1145 -- Check elaboration warning for left side if not in elab code
1147 if Legacy_Elaboration_Checks
1148 and not In_Subprogram_Or_Concurrent_Unit
1150 Check_Elab_Assign
(Lhs
);
1153 -- Save the scenario for later examination by the ABE Processing phase
1155 Record_Elaboration_Scenario
(N
);
1157 -- Set Referenced_As_LHS if appropriate. We are not interested in
1158 -- compiler-generated assignment statements, nor in references outside
1159 -- the extended main source unit. We check whether the Original_Node is
1160 -- in the extended main source unit because in the case of a renaming of
1161 -- a component of a packed array, the Lhs itself has a Sloc from the
1162 -- place of the renaming.
1164 if Comes_From_Source
(N
)
1165 and then (In_Extended_Main_Source_Unit
(Lhs
)
1166 or else In_Extended_Main_Source_Unit
(Original_Node
(Lhs
)))
1168 Set_Referenced_Modified
(Lhs
, Out_Param
=> False);
1171 -- RM 7.3.2 (12/3): An assignment to a view conversion (from a type to
1172 -- one of its ancestors) requires an invariant check. Apply check only
1173 -- if expression comes from source, otherwise it will be applied when
1174 -- value is assigned to source entity. This is not done in GNATprove
1175 -- mode, as GNATprove handles invariant checks itself.
1177 if Nkind
(Lhs
) = N_Type_Conversion
1178 and then Has_Invariants
(Etype
(Expression
(Lhs
)))
1179 and then Comes_From_Source
(Expression
(Lhs
))
1180 and then not GNATprove_Mode
1182 Insert_After
(N
, Make_Invariant_Call
(Expression
(Lhs
)));
1185 -- Final step. If left side is an entity, then we may be able to reset
1186 -- the current tracked values to new safe values. We only have something
1187 -- to do if the left side is an entity name, and expansion has not
1188 -- modified the node into something other than an assignment, and of
1189 -- course we only capture values if it is safe to do so.
1191 if Is_Entity_Name
(Lhs
)
1192 and then Nkind
(N
) = N_Assignment_Statement
1195 Ent
: constant Entity_Id
:= Entity
(Lhs
);
1198 if Safe_To_Capture_Value
(N
, Ent
) then
1200 -- If simple variable on left side, warn if this assignment
1201 -- blots out another one (rendering it useless). We only do
1202 -- this for source assignments, otherwise we can generate bogus
1203 -- warnings when an assignment is rewritten as another
1204 -- assignment, and gets tied up with itself.
1206 -- We also omit the warning if the RHS includes target names,
1207 -- that is to say the Ada 2022 "@" that denotes an instance of
1208 -- the LHS, which indicates that the current value is being
1209 -- used. Note that this implicit reference to the entity on
1210 -- the RHS is not treated as a source reference.
1212 -- There may have been a previous reference to a component of
1213 -- the variable, which in general removes the Last_Assignment
1214 -- field of the variable to indicate a relevant use of the
1215 -- previous assignment.
1217 if Warn_On_Modified_Unread
1218 and then Is_Assignable
(Ent
)
1219 and then Comes_From_Source
(N
)
1220 and then In_Extended_Main_Source_Unit
(Ent
)
1221 and then not Has_Target_Names
(N
)
1223 Warn_On_Useless_Assignment
(Ent
, N
);
1226 -- If we are assigning an access type and the left side is an
1227 -- entity, then make sure that the Is_Known_[Non_]Null flags
1228 -- properly reflect the state of the entity after assignment.
1230 if Is_Access_Type
(T1
) then
1231 if Known_Non_Null
(Rhs
) then
1232 Set_Is_Known_Non_Null
(Ent
, True);
1234 elsif Known_Null
(Rhs
)
1235 and then not Can_Never_Be_Null
(Ent
)
1237 Set_Is_Known_Null
(Ent
, True);
1240 Set_Is_Known_Null
(Ent
, False);
1242 if not Can_Never_Be_Null
(Ent
) then
1243 Set_Is_Known_Non_Null
(Ent
, False);
1247 -- For discrete types, we may be able to set the current value
1248 -- if the value is known at compile time.
1250 elsif Is_Discrete_Type
(T1
)
1251 and then Compile_Time_Known_Value
(Rhs
)
1253 Set_Current_Value
(Ent
, Rhs
);
1255 Set_Current_Value
(Ent
, Empty
);
1258 -- If not safe to capture values, kill them
1266 -- If assigning to an object in whole or in part, note location of
1267 -- assignment in case no one references value. We only do this for
1268 -- source assignments, otherwise we can generate bogus warnings when an
1269 -- assignment is rewritten as another assignment, and gets tied up with
1273 Ent
: constant Entity_Id
:= Get_Enclosing_Object
(Lhs
);
1276 and then Safe_To_Capture_Value
(N
, Ent
)
1277 and then Nkind
(N
) = N_Assignment_Statement
1278 and then Warn_On_Modified_Unread
1279 and then Is_Assignable
(Ent
)
1280 and then Comes_From_Source
(N
)
1281 and then In_Extended_Main_Source_Unit
(Ent
)
1283 Set_Last_Assignment
(Ent
, Lhs
);
1287 Analyze_Dimension
(N
);
1290 Restore_Ghost_Region
(Saved_GM
, Saved_IGR
);
1292 -- If the right-hand side contains target names, expansion has been
1293 -- disabled to prevent expansion that might move target names out of
1294 -- the context of the assignment statement. Restore the expander mode
1295 -- now so that assignment statement can be properly expanded.
1297 if Nkind
(N
) = N_Assignment_Statement
then
1298 if Has_Target_Names
(N
) then
1299 Expander_Mode_Restore
;
1300 Full_Analysis
:= Save_Full_Analysis
;
1301 Current_Assignment
:= Empty
;
1304 pragma Assert
(not Should_Transform_BIP_Assignment
(Typ
=> T1
));
1306 end Analyze_Assignment
;
1308 -----------------------------
1309 -- Analyze_Block_Statement --
1310 -----------------------------
1312 procedure Analyze_Block_Statement
(N
: Node_Id
) is
1313 procedure Install_Return_Entities
(Scop
: Entity_Id
);
1314 -- Install all entities of return statement scope Scop in the visibility
1315 -- chain except for the return object since its entity is reused in a
1318 -----------------------------
1319 -- Install_Return_Entities --
1320 -----------------------------
1322 procedure Install_Return_Entities
(Scop
: Entity_Id
) is
1326 Id
:= First_Entity
(Scop
);
1327 while Present
(Id
) loop
1329 -- Do not install the return object
1331 if Ekind
(Id
) not in E_Constant | E_Variable
1332 or else not Is_Return_Object
(Id
)
1334 Install_Entity
(Id
);
1339 end Install_Return_Entities
;
1341 -- Local constants and variables
1343 Decls
: constant List_Id
:= Declarations
(N
);
1344 Id
: constant Node_Id
:= Identifier
(N
);
1345 HSS
: constant Node_Id
:= Handled_Statement_Sequence
(N
);
1347 Is_BIP_Return_Statement
: Boolean;
1349 -- Start of processing for Analyze_Block_Statement
1352 -- If no handled statement sequence is present, things are really messed
1353 -- up, and we just return immediately (defence against previous errors).
1356 Check_Error_Detected
;
1360 -- Detect whether the block is actually a rewritten return statement of
1361 -- a build-in-place function.
1363 Is_BIP_Return_Statement
:=
1365 and then Present
(Entity
(Id
))
1366 and then Ekind
(Entity
(Id
)) = E_Return_Statement
1367 and then Is_Build_In_Place_Function
1368 (Return_Applies_To
(Entity
(Id
)));
1370 -- Normal processing with HSS present
1373 EH
: constant List_Id
:= Exception_Handlers
(HSS
);
1374 Ent
: Entity_Id
:= Empty
;
1377 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
1378 -- Recursively save value of this global, will be restored on exit
1381 -- Initialize unblocked exit count for statements of begin block
1382 -- plus one for each exception handler that is present.
1384 Unblocked_Exit_Count
:= 1 + List_Length
(EH
);
1386 -- If a label is present analyze it and mark it as referenced
1388 if Present
(Id
) then
1392 -- An error defense. If we have an identifier, but no entity, then
1393 -- something is wrong. If previous errors, then just remove the
1394 -- identifier and continue, otherwise raise an exception.
1397 Check_Error_Detected
;
1398 Set_Identifier
(N
, Empty
);
1401 if Ekind
(Ent
) = E_Label
then
1402 Reinit_Field_To_Zero
(Ent
, F_Enclosing_Scope
);
1405 Mutate_Ekind
(Ent
, E_Block
);
1406 Generate_Reference
(Ent
, N
, ' ');
1407 Generate_Definition
(Ent
);
1409 if Nkind
(Parent
(Ent
)) = N_Implicit_Label_Declaration
then
1410 Set_Label_Construct
(Parent
(Ent
), N
);
1415 -- If no entity set, create a label entity
1418 Ent
:= New_Internal_Entity
(E_Block
, Current_Scope
, Sloc
(N
), 'B');
1419 Set_Identifier
(N
, New_Occurrence_Of
(Ent
, Sloc
(N
)));
1420 Set_Parent
(Ent
, N
);
1423 Set_Etype
(Ent
, Standard_Void_Type
);
1424 Set_Block_Node
(Ent
, Identifier
(N
));
1427 -- The block served as an extended return statement. Ensure that any
1428 -- entities created during the analysis and expansion of the return
1429 -- object declaration are once again visible.
1431 if Is_BIP_Return_Statement
then
1432 Install_Return_Entities
(Ent
);
1435 if Present
(Decls
) then
1436 Analyze_Declarations
(Decls
);
1438 Inspect_Deferred_Constant_Completion
(Decls
);
1442 Process_End_Label
(HSS
, 'e', Ent
);
1444 -- If exception handlers are present, then we indicate that enclosing
1445 -- scopes contain a block with handlers. We only need to mark non-
1448 if Present
(EH
) then
1451 Set_Has_Nested_Block_With_Handler
(S
);
1452 exit when Is_Overloadable
(S
)
1453 or else Ekind
(S
) = E_Package
1454 or else Is_Generic_Unit
(S
);
1459 Check_References
(Ent
);
1460 Update_Use_Clause_Chain
;
1463 if Unblocked_Exit_Count
= 0 then
1464 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1465 Check_Unreachable_Code
(N
);
1467 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1470 end Analyze_Block_Statement
;
1472 --------------------------------
1473 -- Analyze_Compound_Statement --
1474 --------------------------------
1476 procedure Analyze_Compound_Statement
(N
: Node_Id
) is
1478 Analyze_List
(Actions
(N
));
1479 end Analyze_Compound_Statement
;
1481 ----------------------------
1482 -- Analyze_Case_Statement --
1483 ----------------------------
1485 procedure Analyze_Case_Statement
(N
: Node_Id
) is
1486 Exp
: constant Node_Id
:= Expression
(N
);
1488 Statements_Analyzed
: Boolean := False;
1489 -- Set True if at least some statement sequences get analyzed. If False
1490 -- on exit, means we had a serious error that prevented full analysis of
1491 -- the case statement, and as a result it is not a good idea to output
1492 -- warning messages about unreachable code.
1494 Is_General_Case_Statement
: Boolean := False;
1495 -- Set True (later) if type of case expression is not discrete
1497 procedure Non_Static_Choice_Error
(Choice
: Node_Id
);
1498 -- Error routine invoked by the generic instantiation below when the
1499 -- case statement has a non static choice.
1501 procedure Process_Statements
(Alternative
: Node_Id
);
1502 -- Analyzes the statements associated with a case alternative. Needed
1503 -- by instantiation below.
1505 package Analyze_Case_Choices
is new
1506 Generic_Analyze_Choices
1507 (Process_Associated_Node
=> Process_Statements
);
1508 use Analyze_Case_Choices
;
1509 -- Instantiation of the generic choice analysis package
1511 package Check_Case_Choices
is new
1512 Generic_Check_Choices
1513 (Process_Empty_Choice
=> No_OP
,
1514 Process_Non_Static_Choice
=> Non_Static_Choice_Error
,
1515 Process_Associated_Node
=> No_OP
);
1516 use Check_Case_Choices
;
1517 -- Instantiation of the generic choice processing package
1519 -----------------------------
1520 -- Non_Static_Choice_Error --
1521 -----------------------------
1523 procedure Non_Static_Choice_Error
(Choice
: Node_Id
) is
1525 Flag_Non_Static_Expr
1526 ("choice given in case statement is not static!", Choice
);
1527 end Non_Static_Choice_Error
;
1529 ------------------------
1530 -- Process_Statements --
1531 ------------------------
1533 procedure Process_Statements
(Alternative
: Node_Id
) is
1534 Choices
: constant List_Id
:= Discrete_Choices
(Alternative
);
1538 if Is_General_Case_Statement
then
1540 -- Processing deferred in this case; decls associated with
1541 -- pattern match bindings don't exist yet.
1544 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
1545 Statements_Analyzed
:= True;
1547 -- An interesting optimization. If the case statement expression
1548 -- is a simple entity, then we can set the current value within an
1549 -- alternative if the alternative has one possible value.
1553 -- when 2 | 3 => beta
1554 -- when others => gamma
1556 -- Here we know that N is initially 1 within alpha, but for beta and
1557 -- gamma, we do not know anything more about the initial value.
1559 if Is_Entity_Name
(Exp
) then
1560 Ent
:= Entity
(Exp
);
1562 if Is_Object
(Ent
) then
1563 if List_Length
(Choices
) = 1
1564 and then Nkind
(First
(Choices
)) in N_Subexpr
1565 and then Compile_Time_Known_Value
(First
(Choices
))
1567 Set_Current_Value
(Entity
(Exp
), First
(Choices
));
1570 Analyze_Statements
(Statements
(Alternative
));
1572 -- After analyzing the case, set the current value to empty
1573 -- since we won't know what it is for the next alternative
1574 -- (unless reset by this same circuit), or after the case.
1576 Set_Current_Value
(Entity
(Exp
), Empty
);
1581 -- Case where expression is not an entity name of an object
1583 Analyze_Statements
(Statements
(Alternative
));
1584 end Process_Statements
;
1588 Exp_Type
: Entity_Id
;
1589 Exp_Btype
: Entity_Id
;
1591 Others_Present
: Boolean;
1592 -- Indicates if Others was present
1594 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
1595 -- Recursively save value of this global, will be restored on exit
1597 -- Start of processing for Analyze_Case_Statement
1602 -- The expression must be of any discrete type. In rare cases, the
1603 -- expander constructs a case statement whose expression has a private
1604 -- type whose full view is discrete. This can happen when generating
1605 -- a stream operation for a variant type after the type is frozen,
1606 -- when the partial of view of the type of the discriminant is private.
1607 -- In that case, use the full view to analyze case alternatives.
1609 if not Is_Overloaded
(Exp
)
1610 and then not Comes_From_Source
(N
)
1611 and then Is_Private_Type
(Etype
(Exp
))
1612 and then Present
(Full_View
(Etype
(Exp
)))
1613 and then Is_Discrete_Type
(Full_View
(Etype
(Exp
)))
1616 Exp_Type
:= Full_View
(Etype
(Exp
));
1618 -- For Ada, overloading might be ok because subsequently filtering
1619 -- out non-discretes may resolve the ambiguity.
1620 -- But GNAT extensions allow casing on non-discretes.
1622 elsif Core_Extensions_Allowed
and then Is_Overloaded
(Exp
) then
1624 -- It would be nice if we could generate all the right error
1625 -- messages by calling "Resolve (Exp, Any_Type);" in the
1626 -- same way that they are generated a few lines below by the
1627 -- call "Analyze_And_Resolve (Exp, Any_Discrete);".
1628 -- Unfortunately, Any_Type and Any_Discrete are not treated
1629 -- consistently (specifically, by Sem_Type.Covers), so that
1633 ("selecting expression of general case statement is ambiguous",
1637 -- Check for a GNAT-extension "general" case statement (i.e., one where
1638 -- the type of the selecting expression is not discrete).
1640 elsif Core_Extensions_Allowed
1641 and then not Is_Discrete_Type
(Etype
(Exp
))
1643 Resolve
(Exp
, Etype
(Exp
));
1644 Exp_Type
:= Etype
(Exp
);
1645 Is_General_Case_Statement
:= True;
1647 Analyze_And_Resolve
(Exp
, Any_Discrete
);
1648 Exp_Type
:= Etype
(Exp
);
1651 Check_Unset_Reference
(Exp
);
1652 Exp_Btype
:= Base_Type
(Exp_Type
);
1654 -- The expression must be of a discrete type which must be determinable
1655 -- independently of the context in which the expression occurs, but
1656 -- using the fact that the expression must be of a discrete type.
1657 -- Moreover, the type this expression must not be a character literal
1658 -- (which is always ambiguous) or, for Ada-83, a generic formal type.
1660 -- If error already reported by Resolve, nothing more to do
1662 if Exp_Btype
= Any_Discrete
or else Exp_Btype
= Any_Type
then
1665 elsif Exp_Btype
= Any_Character
then
1667 ("character literal as case expression is ambiguous", Exp
);
1670 elsif Ada_Version
= Ada_83
1671 and then (Is_Generic_Type
(Exp_Btype
)
1672 or else Is_Generic_Type
(Root_Type
(Exp_Btype
)))
1675 ("(Ada 83) case expression cannot be of a generic type", Exp
);
1678 elsif not Core_Extensions_Allowed
1679 and then not Is_Discrete_Type
(Exp_Type
)
1682 ("expression in case statement must be of a discrete_Type", Exp
);
1686 -- If the case expression is a formal object of mode in out, then treat
1687 -- it as having a nonstatic subtype by forcing use of the base type
1688 -- (which has to get passed to Check_Case_Choices below). Also use base
1689 -- type when the case expression is parenthesized.
1691 if Paren_Count
(Exp
) > 0
1692 or else (Is_Entity_Name
(Exp
)
1693 and then Ekind
(Entity
(Exp
)) = E_Generic_In_Out_Parameter
)
1695 Exp_Type
:= Exp_Btype
;
1698 -- Call instantiated procedures to analyze and check discrete choices
1700 Unblocked_Exit_Count
:= 0;
1702 Analyze_Choices
(Alternatives
(N
), Exp_Type
);
1703 Check_Choices
(N
, Alternatives
(N
), Exp_Type
, Others_Present
);
1705 if Is_General_Case_Statement
then
1706 -- Work normally done in Process_Statements was deferred; do that
1707 -- deferred work now that Check_Choices has had a chance to create
1708 -- any needed pattern-match-binding declarations.
1710 Alt
: Node_Id
:= First
(Alternatives
(N
));
1712 while Present
(Alt
) loop
1713 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
1714 Analyze_Statements
(Statements
(Alt
));
1720 if Exp_Type
= Universal_Integer
and then not Others_Present
then
1721 Error_Msg_N
("case on universal integer requires OTHERS choice", Exp
);
1724 -- If all our exits were blocked by unconditional transfers of control,
1725 -- then the entire CASE statement acts as an unconditional transfer of
1726 -- control, so treat it like one, and check unreachable code. Skip this
1727 -- test if we had serious errors preventing any statement analysis.
1729 if Unblocked_Exit_Count
= 0 and then Statements_Analyzed
then
1730 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1731 Check_Unreachable_Code
(N
);
1733 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1736 -- If the expander is active it will detect the case of a statically
1737 -- determined single alternative and remove warnings for the case, but
1738 -- if we are not doing expansion, that circuit won't be active. Here we
1739 -- duplicate the effect of removing warnings in the same way, so that
1740 -- we will get the same set of warnings in -gnatc mode.
1742 if not Expander_Active
1743 and then Compile_Time_Known_Value
(Expression
(N
))
1744 and then Serious_Errors_Detected
= 0
1747 Chosen
: constant Node_Id
:= Find_Static_Alternative
(N
);
1751 Alt
:= First
(Alternatives
(N
));
1752 while Present
(Alt
) loop
1753 if Alt
/= Chosen
then
1754 Remove_Warning_Messages
(Statements
(Alt
));
1761 end Analyze_Case_Statement
;
1763 ----------------------------
1764 -- Analyze_Exit_Statement --
1765 ----------------------------
1767 -- If the exit includes a name, it must be the name of a currently open
1768 -- loop. Otherwise there must be an innermost open loop on the stack, to
1769 -- which the statement implicitly refers.
1771 -- Additionally, in SPARK mode:
1773 -- The exit can only name the closest enclosing loop;
1775 -- An exit with a when clause must be directly contained in a loop;
1777 -- An exit without a when clause must be directly contained in an
1778 -- if-statement with no elsif or else, which is itself directly contained
1779 -- in a loop. The exit must be the last statement in the if-statement.
1781 procedure Analyze_Exit_Statement
(N
: Node_Id
) is
1782 Target
: constant Node_Id
:= Name
(N
);
1783 Cond
: constant Node_Id
:= Condition
(N
);
1784 Scope_Id
: Entity_Id
:= Empty
; -- initialize to prevent warning
1790 Check_Unreachable_Code
(N
);
1793 if Present
(Target
) then
1795 U_Name
:= Entity
(Target
);
1797 if not In_Open_Scopes
(U_Name
) or else Ekind
(U_Name
) /= E_Loop
then
1798 Error_Msg_N
("invalid loop name in exit statement", N
);
1802 Set_Has_Exit
(U_Name
);
1809 for J
in reverse 0 .. Scope_Stack
.Last
loop
1810 Scope_Id
:= Scope_Stack
.Table
(J
).Entity
;
1811 Kind
:= Ekind
(Scope_Id
);
1813 if Kind
= E_Loop
and then (No
(Target
) or else Scope_Id
= U_Name
) then
1814 Set_Has_Exit
(Scope_Id
);
1817 elsif Kind
= E_Block
1818 or else Kind
= E_Loop
1819 or else Kind
= E_Return_Statement
1825 ("cannot exit from program unit or accept statement", N
);
1830 -- Verify that if present the condition is a Boolean expression
1832 if Present
(Cond
) then
1833 Analyze_And_Resolve
(Cond
, Any_Boolean
);
1834 Check_Unset_Reference
(Cond
);
1837 -- Chain exit statement to associated loop entity
1839 Set_Next_Exit_Statement
(N
, First_Exit_Statement
(Scope_Id
));
1840 Set_First_Exit_Statement
(Scope_Id
, N
);
1842 -- Since the exit may take us out of a loop, any previous assignment
1843 -- statement is not useless, so clear last assignment indications. It
1844 -- is OK to keep other current values, since if the exit statement
1845 -- does not exit, then the current values are still valid.
1847 Kill_Current_Values
(Last_Assignment_Only
=> True);
1848 end Analyze_Exit_Statement
;
1850 ----------------------------
1851 -- Analyze_Goto_Statement --
1852 ----------------------------
1854 procedure Analyze_Goto_Statement
(N
: Node_Id
) is
1855 Label
: constant Node_Id
:= Name
(N
);
1856 Scope_Id
: Entity_Id
;
1857 Label_Scope
: Entity_Id
;
1858 Label_Ent
: Entity_Id
;
1861 -- Actual semantic checks
1863 Check_Unreachable_Code
(N
);
1864 Kill_Current_Values
(Last_Assignment_Only
=> True);
1867 Label_Ent
:= Entity
(Label
);
1869 -- Ignore previous error
1871 if Label_Ent
= Any_Id
then
1872 Check_Error_Detected
;
1875 -- We just have a label as the target of a goto
1877 elsif Ekind
(Label_Ent
) /= E_Label
then
1878 Error_Msg_N
("target of goto statement must be a label", Label
);
1881 -- Check that the target of the goto is reachable according to Ada
1882 -- scoping rules. Note: the special gotos we generate for optimizing
1883 -- local handling of exceptions would violate these rules, but we mark
1884 -- such gotos as analyzed when built, so this code is never entered.
1886 elsif not Reachable
(Label_Ent
) then
1887 Error_Msg_N
("target of goto statement is not reachable", Label
);
1891 -- Here if goto passes initial validity checks
1893 Label_Scope
:= Enclosing_Scope
(Label_Ent
);
1895 for J
in reverse 0 .. Scope_Stack
.Last
loop
1896 Scope_Id
:= Scope_Stack
.Table
(J
).Entity
;
1898 if Label_Scope
= Scope_Id
1899 or else Ekind
(Scope_Id
) not in
1900 E_Block | E_Loop | E_Return_Statement
1902 if Scope_Id
/= Label_Scope
then
1904 ("cannot exit from program unit or accept statement", N
);
1911 raise Program_Error
;
1912 end Analyze_Goto_Statement
;
1914 ---------------------------------
1915 -- Analyze_Goto_When_Statement --
1916 ---------------------------------
1918 procedure Analyze_Goto_When_Statement
(N
: Node_Id
) is
1920 -- Verify the condition is a Boolean expression
1922 Analyze_And_Resolve
(Condition
(N
), Any_Boolean
);
1923 Check_Unset_Reference
(Condition
(N
));
1924 end Analyze_Goto_When_Statement
;
1926 --------------------------
1927 -- Analyze_If_Statement --
1928 --------------------------
1930 -- A special complication arises in the analysis of if statements
1932 -- The expander has circuitry to completely delete code that it can tell
1933 -- will not be executed (as a result of compile time known conditions). In
1934 -- the analyzer, we ensure that code that will be deleted in this manner
1935 -- is analyzed but not expanded. This is obviously more efficient, but
1936 -- more significantly, difficulties arise if code is expanded and then
1937 -- eliminated (e.g. exception table entries disappear). Similarly, itypes
1938 -- generated in deleted code must be frozen from start, because the nodes
1939 -- on which they depend will not be available at the freeze point.
1941 procedure Analyze_If_Statement
(N
: Node_Id
) is
1942 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
1943 -- Recursively save value of this global, will be restored on exit
1945 Save_In_Deleted_Code
: Boolean := In_Deleted_Code
;
1947 Del
: Boolean := False;
1948 -- This flag gets set True if a True condition has been found, which
1949 -- means that remaining ELSE/ELSIF parts are deleted.
1951 procedure Analyze_Cond_Then
(Cnode
: Node_Id
);
1952 -- This is applied to either the N_If_Statement node itself or to an
1953 -- N_Elsif_Part node. It deals with analyzing the condition and the THEN
1954 -- statements associated with it.
1956 -----------------------
1957 -- Analyze_Cond_Then --
1958 -----------------------
1960 procedure Analyze_Cond_Then
(Cnode
: Node_Id
) is
1961 Cond
: constant Node_Id
:= Condition
(Cnode
);
1962 Tstm
: constant List_Id
:= Then_Statements
(Cnode
);
1965 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
1966 Analyze_And_Resolve
(Cond
, Any_Boolean
);
1967 Check_Unset_Reference
(Cond
);
1968 Set_Current_Value_Condition
(Cnode
);
1970 -- If already deleting, then just analyze then statements
1973 Analyze_Statements
(Tstm
);
1975 -- Compile time known value, not deleting yet
1977 elsif Compile_Time_Known_Value
(Cond
) then
1978 Save_In_Deleted_Code
:= In_Deleted_Code
;
1980 -- If condition is True, then analyze the THEN statements and set
1981 -- no expansion for ELSE and ELSIF parts.
1983 if Is_True
(Expr_Value
(Cond
)) then
1984 Analyze_Statements
(Tstm
);
1986 Expander_Mode_Save_And_Set
(False);
1987 In_Deleted_Code
:= True;
1989 -- If condition is False, analyze THEN with expansion off
1991 else pragma Assert
(Is_False
(Expr_Value
(Cond
)));
1992 Expander_Mode_Save_And_Set
(False);
1993 In_Deleted_Code
:= True;
1994 Analyze_Statements
(Tstm
);
1995 Expander_Mode_Restore
;
1996 In_Deleted_Code
:= Save_In_Deleted_Code
;
1999 -- Not known at compile time, not deleting, normal analysis
2002 Analyze_Statements
(Tstm
);
2004 end Analyze_Cond_Then
;
2009 -- For iterating over elsif parts
2011 -- Start of processing for Analyze_If_Statement
2014 -- Initialize exit count for else statements. If there is no else part,
2015 -- this count will stay non-zero reflecting the fact that the uncovered
2016 -- else case is an unblocked exit.
2018 Unblocked_Exit_Count
:= 1;
2019 Analyze_Cond_Then
(N
);
2021 -- Now to analyze the elsif parts if any are present
2023 E
:= First
(Elsif_Parts
(N
));
2024 while Present
(E
) loop
2025 Analyze_Cond_Then
(E
);
2029 if Present
(Else_Statements
(N
)) then
2030 Analyze_Statements
(Else_Statements
(N
));
2033 -- If all our exits were blocked by unconditional transfers of control,
2034 -- then the entire IF statement acts as an unconditional transfer of
2035 -- control, so treat it like one, and check unreachable code.
2037 if Unblocked_Exit_Count
= 0 then
2038 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
2039 Check_Unreachable_Code
(N
);
2041 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
2045 Expander_Mode_Restore
;
2046 In_Deleted_Code
:= Save_In_Deleted_Code
;
2049 if not Expander_Active
2050 and then Compile_Time_Known_Value
(Condition
(N
))
2051 and then Serious_Errors_Detected
= 0
2053 if Is_True
(Expr_Value
(Condition
(N
))) then
2054 Remove_Warning_Messages
(Else_Statements
(N
));
2056 E
:= First
(Elsif_Parts
(N
));
2057 while Present
(E
) loop
2058 Remove_Warning_Messages
(Then_Statements
(E
));
2063 Remove_Warning_Messages
(Then_Statements
(N
));
2067 -- Warn on redundant if statement that has no effect
2069 -- Note, we could also check empty ELSIF parts ???
2071 if Warn_On_Redundant_Constructs
2073 -- If statement must be from source
2075 and then Comes_From_Source
(N
)
2077 -- Condition must not have obvious side effect
2079 and then Has_No_Obvious_Side_Effects
(Condition
(N
))
2081 -- No elsif parts of else part
2083 and then No
(Elsif_Parts
(N
))
2084 and then No
(Else_Statements
(N
))
2086 -- Then must be a single null statement
2088 and then List_Length
(Then_Statements
(N
)) = 1
2090 -- Go to original node, since we may have rewritten something as
2091 -- a null statement (e.g. a case we could figure the outcome of).
2094 T
: constant Node_Id
:= First
(Then_Statements
(N
));
2095 S
: constant Node_Id
:= Original_Node
(T
);
2098 if Comes_From_Source
(S
) and then Nkind
(S
) = N_Null_Statement
then
2099 Error_Msg_N
("if statement has no effect?r?", N
);
2103 end Analyze_If_Statement
;
2105 ----------------------------------------
2106 -- Analyze_Implicit_Label_Declaration --
2107 ----------------------------------------
2109 -- An implicit label declaration is generated in the innermost enclosing
2110 -- declarative part. This is done for labels, and block and loop names.
2112 procedure Analyze_Implicit_Label_Declaration
(N
: Node_Id
) is
2113 Id
: constant Node_Id
:= Defining_Identifier
(N
);
2116 Mutate_Ekind
(Id
, E_Label
);
2117 Set_Etype
(Id
, Standard_Void_Type
);
2118 Set_Enclosing_Scope
(Id
, Current_Scope
);
2120 -- A label declared within a Ghost region becomes Ghost (SPARK RM
2123 if Ghost_Mode
> None
then
2124 Set_Is_Ghost_Entity
(Id
);
2126 end Analyze_Implicit_Label_Declaration
;
2128 ------------------------------
2129 -- Analyze_Iteration_Scheme --
2130 ------------------------------
2132 procedure Analyze_Iteration_Scheme
(N
: Node_Id
) is
2134 Iter_Spec
: Node_Id
;
2135 Loop_Spec
: Node_Id
;
2138 -- For an infinite loop, there is no iteration scheme
2144 Cond
:= Condition
(N
);
2145 Iter_Spec
:= Iterator_Specification
(N
);
2146 Loop_Spec
:= Loop_Parameter_Specification
(N
);
2148 if Present
(Cond
) then
2149 Analyze_And_Resolve
(Cond
, Any_Boolean
);
2150 Check_Unset_Reference
(Cond
);
2151 Set_Current_Value_Condition
(N
);
2153 elsif Present
(Iter_Spec
) then
2154 Analyze_Iterator_Specification
(Iter_Spec
);
2157 Analyze_Loop_Parameter_Specification
(Loop_Spec
);
2159 end Analyze_Iteration_Scheme
;
2161 ------------------------------------
2162 -- Analyze_Iterator_Specification --
2163 ------------------------------------
2165 procedure Analyze_Iterator_Specification
(N
: Node_Id
) is
2166 Def_Id
: constant Node_Id
:= Defining_Identifier
(N
);
2167 Iter_Name
: constant Node_Id
:= Name
(N
);
2168 Loc
: constant Source_Ptr
:= Sloc
(N
);
2169 Subt
: constant Node_Id
:= Subtype_Indication
(N
);
2171 Bas
: Entity_Id
:= Empty
; -- initialize to prevent warning
2174 procedure Check_Reverse_Iteration
(Typ
: Entity_Id
);
2175 -- For an iteration over a container, if the loop carries the Reverse
2176 -- indicator, verify that the container type has an Iterate aspect that
2177 -- implements the reversible iterator interface.
2179 procedure Check_Subtype_Definition
(Comp_Type
: Entity_Id
);
2180 -- If a subtype indication is present, verify that it is consistent
2181 -- with the component type of the array or container name.
2182 -- In Ada 2022, the subtype indication may be an access definition,
2183 -- if the array or container has elements of an anonymous access type.
2185 function Get_Cursor_Type
(Typ
: Entity_Id
) return Entity_Id
;
2186 -- For containers with Iterator and related aspects, the cursor is
2187 -- obtained by locating an entity with the proper name in the scope
2190 -----------------------------
2191 -- Check_Reverse_Iteration --
2192 -----------------------------
2194 procedure Check_Reverse_Iteration
(Typ
: Entity_Id
) is
2196 if Reverse_Present
(N
) then
2197 if Is_Array_Type
(Typ
)
2198 or else Is_Reversible_Iterator
(Typ
)
2200 (Has_Aspect
(Typ
, Aspect_Iterable
)
2203 (Get_Iterable_Type_Primitive
(Typ
, Name_Previous
)))
2208 ("container type does not support reverse iteration", N
);
2211 end Check_Reverse_Iteration
;
2213 -------------------------------
2214 -- Check_Subtype_Definition --
2215 -------------------------------
2217 procedure Check_Subtype_Definition
(Comp_Type
: Entity_Id
) is
2223 if Is_Anonymous_Access_Type
(Entity
(Subt
)) then
2224 if not Is_Anonymous_Access_Type
(Comp_Type
) then
2226 ("component type& is not an anonymous access",
2229 elsif not Conforming_Types
2230 (Designated_Type
(Entity
(Subt
)),
2231 Designated_Type
(Comp_Type
),
2235 ("subtype indication does not match component type&",
2239 elsif not Covers
(Base_Type
(Bas
), Comp_Type
)
2240 or else not Subtypes_Statically_Match
(Bas
, Comp_Type
)
2242 if Is_Array_Type
(Typ
) then
2244 ("subtype indication does not match component type&",
2248 ("subtype indication does not match element type&",
2252 end Check_Subtype_Definition
;
2254 ---------------------
2255 -- Get_Cursor_Type --
2256 ---------------------
2258 function Get_Cursor_Type
(Typ
: Entity_Id
) return Entity_Id
is
2262 -- If iterator type is derived, the cursor is declared in the scope
2263 -- of the parent type.
2265 if Is_Derived_Type
(Typ
) then
2266 Ent
:= First_Entity
(Scope
(Etype
(Typ
)));
2268 Ent
:= First_Entity
(Scope
(Typ
));
2271 while Present
(Ent
) loop
2272 exit when Chars
(Ent
) = Name_Cursor
;
2280 -- The cursor is the target of generated assignments in the
2281 -- loop, and cannot have a limited type.
2283 if Is_Limited_Type
(Etype
(Ent
)) then
2284 Error_Msg_N
("cursor type cannot be limited", N
);
2288 end Get_Cursor_Type
;
2290 -- Start of processing for Analyze_Iterator_Specification
2293 Enter_Name
(Def_Id
);
2295 -- AI12-0151 specifies that when the subtype indication is present, it
2296 -- must statically match the type of the array or container element.
2297 -- To simplify this check, we introduce a subtype declaration with the
2298 -- given subtype indication when it carries a constraint, and rewrite
2299 -- the original as a reference to the created subtype entity.
2301 if Present
(Subt
) then
2302 if Nkind
(Subt
) = N_Subtype_Indication
then
2304 S
: constant Entity_Id
:= Make_Temporary
(Sloc
(Subt
), 'S');
2305 Decl
: constant Node_Id
:=
2306 Make_Subtype_Declaration
(Loc
,
2307 Defining_Identifier
=> S
,
2308 Subtype_Indication
=> New_Copy_Tree
(Subt
));
2310 Insert_Action
(N
, Decl
);
2312 Rewrite
(Subt
, New_Occurrence_Of
(S
, Sloc
(Subt
)));
2315 -- Ada 2022: the subtype definition may be for an anonymous
2318 elsif Nkind
(Subt
) = N_Access_Definition
then
2320 S
: constant Entity_Id
:= Make_Temporary
(Sloc
(Subt
), 'S');
2323 if Present
(Subtype_Mark
(Subt
)) then
2325 Make_Full_Type_Declaration
(Loc
,
2326 Defining_Identifier
=> S
,
2328 Make_Access_To_Object_Definition
(Loc
,
2329 All_Present
=> True,
2330 Subtype_Indication
=>
2331 New_Copy_Tree
(Subtype_Mark
(Subt
))));
2335 Make_Full_Type_Declaration
(Loc
,
2336 Defining_Identifier
=> S
,
2339 (Access_To_Subprogram_Definition
(Subt
)));
2342 Insert_Before
(Parent
(Parent
(N
)), Decl
);
2344 Freeze_Before
(First
(Statements
(Parent
(Parent
(N
)))), S
);
2345 Rewrite
(Subt
, New_Occurrence_Of
(S
, Sloc
(Subt
)));
2351 -- Save entity of subtype indication for subsequent check
2353 Bas
:= Entity
(Subt
);
2356 Preanalyze_Range
(Iter_Name
);
2358 -- If the domain of iteration is a function call, make sure the function
2359 -- itself is frozen. This is an issue if this is a local expression
2362 if Nkind
(Iter_Name
) = N_Function_Call
2363 and then Is_Entity_Name
(Name
(Iter_Name
))
2364 and then Full_Analysis
2365 and then (In_Assertion_Expr
= 0 or else Assertions_Enabled
)
2367 Freeze_Before
(N
, Entity
(Name
(Iter_Name
)));
2370 -- Set the kind of the loop variable, which is not visible within the
2373 Mutate_Ekind
(Def_Id
, E_Variable
);
2375 -- Provide a link between the iterator variable and the container, for
2376 -- subsequent use in cross-reference and modification information.
2378 if Of_Present
(N
) then
2379 Set_Related_Expression
(Def_Id
, Iter_Name
);
2381 -- For a container, the iterator is specified through the aspect
2383 if not Is_Array_Type
(Etype
(Iter_Name
)) then
2385 Iterator
: constant Entity_Id
:=
2386 Find_Value_Of_Aspect
2387 (Etype
(Iter_Name
), Aspect_Default_Iterator
);
2393 -- The domain of iteration must implement either the RM
2394 -- iterator interface, or the SPARK Iterable aspect.
2396 if No
(Iterator
) then
2397 if No
(Find_Aspect
(Etype
(Iter_Name
), Aspect_Iterable
)) then
2399 ("cannot iterate over&",
2400 N
, Base_Type
(Etype
(Iter_Name
)));
2404 elsif not Is_Overloaded
(Iterator
) then
2405 Check_Reverse_Iteration
(Etype
(Iterator
));
2407 -- If Iterator is overloaded, use reversible iterator if one is
2410 elsif Is_Overloaded
(Iterator
) then
2411 Get_First_Interp
(Iterator
, I
, It
);
2412 while Present
(It
.Nam
) loop
2413 if Ekind
(It
.Nam
) = E_Function
2414 and then Is_Reversible_Iterator
(Etype
(It
.Nam
))
2416 Set_Etype
(Iterator
, It
.Typ
);
2417 Set_Entity
(Iterator
, It
.Nam
);
2421 Get_Next_Interp
(I
, It
);
2424 Check_Reverse_Iteration
(Etype
(Iterator
));
2430 -- If the domain of iteration is an expression, create a declaration for
2431 -- it, so that finalization actions are introduced outside of the loop.
2432 -- The declaration must be a renaming (both in GNAT and GNATprove
2433 -- modes), because the body of the loop may assign to elements.
2435 if not Is_Entity_Name
(Iter_Name
)
2437 -- Do not perform this expansion in preanalysis
2439 and then Full_Analysis
2441 -- Do not perform this expansion when expansion is disabled, where the
2442 -- temporary may hide the transformation of a selected component into
2443 -- a prefixed function call, and references need to see the original
2446 and then (Expander_Active
or GNATprove_Mode
)
2449 Id
: constant Entity_Id
:= Make_Temporary
(Loc
, 'R', Iter_Name
);
2455 -- If the domain of iteration is an array component that depends
2456 -- on a discriminant, create actual subtype for it. Preanalysis
2457 -- does not generate the actual subtype of a selected component.
2459 if Nkind
(Iter_Name
) = N_Selected_Component
2460 and then Is_Array_Type
(Etype
(Iter_Name
))
2463 Build_Actual_Subtype_Of_Component
2464 (Etype
(Selector_Name
(Iter_Name
)), Iter_Name
);
2465 Insert_Action
(N
, Act_S
);
2467 if Present
(Act_S
) then
2468 Typ
:= Defining_Identifier
(Act_S
);
2470 Typ
:= Etype
(Iter_Name
);
2474 Typ
:= Etype
(Iter_Name
);
2476 -- Verify that the expression produces an iterator
2478 if not Of_Present
(N
) and then not Is_Iterator
(Typ
)
2479 and then not Is_Array_Type
(Typ
)
2480 and then No
(Find_Aspect
(Typ
, Aspect_Iterable
))
2483 ("expect object that implements iterator interface",
2488 -- Protect against malformed iterator
2490 if Typ
= Any_Type
then
2491 Error_Msg_N
("invalid expression in loop iterator", Iter_Name
);
2495 if not Of_Present
(N
) then
2496 Check_Reverse_Iteration
(Typ
);
2499 -- For an element iteration over a slice, we must complete
2500 -- the resolution and expansion of the slice bounds. These
2501 -- can be arbitrary expressions, and the preanalysis that
2502 -- was performed in preparation for the iteration may have
2503 -- generated an itype whose bounds must be fully expanded.
2504 -- We set the parent node to provide a proper insertion
2505 -- point for generated actions, if any.
2507 if Nkind
(Iter_Name
) = N_Slice
2508 and then Nkind
(Discrete_Range
(Iter_Name
)) = N_Range
2509 and then not Analyzed
(Discrete_Range
(Iter_Name
))
2512 Indx
: constant Node_Id
:=
2513 Entity
(First_Index
(Etype
(Iter_Name
)));
2515 Set_Parent
(Indx
, Iter_Name
);
2516 Resolve
(Scalar_Range
(Indx
), Etype
(Indx
));
2520 -- The name in the renaming declaration may be a function call.
2521 -- Indicate that it does not come from source, to suppress
2522 -- spurious warnings on renamings of parameterless functions,
2523 -- a common enough idiom in user-defined iterators.
2526 Make_Object_Renaming_Declaration
(Loc
,
2527 Defining_Identifier
=> Id
,
2528 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2530 New_Copy_Tree
(Iter_Name
, New_Sloc
=> Loc
));
2531 Set_Comes_From_Iterator
(Decl
);
2533 Insert_Actions
(Parent
(Parent
(N
)), New_List
(Decl
));
2534 Rewrite
(Name
(N
), New_Occurrence_Of
(Id
, Loc
));
2536 Set_Etype
(Id
, Typ
);
2537 Set_Etype
(Name
(N
), Typ
);
2540 -- Container is an entity or an array with uncontrolled components, or
2541 -- else it is a container iterator given by a function call, typically
2542 -- called Iterate in the case of predefined containers, even though
2543 -- Iterate is not a reserved name. What matters is that the return type
2544 -- of the function is an iterator type.
2546 elsif Is_Entity_Name
(Iter_Name
) then
2547 Analyze
(Iter_Name
);
2549 if Nkind
(Iter_Name
) = N_Function_Call
then
2551 C
: constant Node_Id
:= Name
(Iter_Name
);
2556 if not Is_Overloaded
(Iter_Name
) then
2557 Resolve
(Iter_Name
, Etype
(C
));
2560 Get_First_Interp
(C
, I
, It
);
2561 while It
.Typ
/= Empty
loop
2562 if Reverse_Present
(N
) then
2563 if Is_Reversible_Iterator
(It
.Typ
) then
2564 Resolve
(Iter_Name
, It
.Typ
);
2568 elsif Is_Iterator
(It
.Typ
) then
2569 Resolve
(Iter_Name
, It
.Typ
);
2573 Get_Next_Interp
(I
, It
);
2578 -- Domain of iteration is not overloaded
2581 Resolve
(Iter_Name
);
2584 if not Of_Present
(N
) then
2585 Check_Reverse_Iteration
(Etype
(Iter_Name
));
2589 -- Get base type of container, for proper retrieval of Cursor type
2590 -- and primitive operations.
2592 Typ
:= Base_Type
(Etype
(Iter_Name
));
2594 if Is_Array_Type
(Typ
) then
2595 if Of_Present
(N
) then
2596 Set_Etype
(Def_Id
, Component_Type
(Typ
));
2598 -- The loop variable is aliased if the array components are
2599 -- aliased. Likewise for the independent aspect.
2601 Set_Is_Aliased
(Def_Id
, Has_Aliased_Components
(Typ
));
2602 Set_Is_Independent
(Def_Id
, Has_Independent_Components
(Typ
));
2604 -- AI12-0047 stipulates that the domain (array or container)
2605 -- cannot be a component that depends on a discriminant if the
2606 -- enclosing object is mutable, to prevent a modification of the
2607 -- domain of iteration in the course of an iteration.
2609 -- If the object is an expression it has been captured in a
2610 -- temporary, so examine original node.
2612 if Nkind
(Original_Node
(Iter_Name
)) = N_Selected_Component
2613 and then Is_Dependent_Component_Of_Mutable_Object
2614 (Original_Node
(Iter_Name
))
2617 ("iterable name cannot be a discriminant-dependent "
2618 & "component of a mutable object", N
);
2621 Check_Subtype_Definition
(Component_Type
(Typ
));
2623 -- Here we have a missing Range attribute
2627 ("missing Range attribute in iteration over an array", N
);
2629 -- In Ada 2012 mode, this may be an attempt at an iterator
2631 if Ada_Version
>= Ada_2012
then
2633 ("\if& is meant to designate an element of the array, use OF",
2637 -- Prevent cascaded errors
2639 Mutate_Ekind
(Def_Id
, E_Loop_Parameter
);
2640 Set_Etype
(Def_Id
, Etype
(First_Index
(Typ
)));
2643 -- Check for type error in iterator
2645 elsif Typ
= Any_Type
then
2648 -- Iteration over a container
2651 Mutate_Ekind
(Def_Id
, E_Loop_Parameter
);
2652 Error_Msg_Ada_2012_Feature
("container iterator", Sloc
(N
));
2656 if Of_Present
(N
) then
2657 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2659 Elt
: constant Entity_Id
:=
2660 Get_Iterable_Type_Primitive
(Typ
, Name_Element
);
2664 ("missing Element primitive for iteration", N
);
2666 Set_Etype
(Def_Id
, Etype
(Elt
));
2667 Check_Reverse_Iteration
(Typ
);
2671 Check_Subtype_Definition
(Etype
(Def_Id
));
2673 -- For a predefined container, the type of the loop variable is
2674 -- the Iterator_Element aspect of the container type.
2678 Element
: constant Entity_Id
:=
2679 Find_Value_Of_Aspect
2680 (Typ
, Aspect_Iterator_Element
);
2681 Iterator
: constant Entity_Id
:=
2682 Find_Value_Of_Aspect
2683 (Typ
, Aspect_Default_Iterator
);
2684 Orig_Iter_Name
: constant Node_Id
:=
2685 Original_Node
(Iter_Name
);
2686 Cursor_Type
: Entity_Id
;
2689 if No
(Element
) then
2690 Error_Msg_NE
("cannot iterate over&", N
, Typ
);
2694 Set_Etype
(Def_Id
, Entity
(Element
));
2695 Cursor_Type
:= Get_Cursor_Type
(Typ
);
2696 pragma Assert
(Present
(Cursor_Type
));
2698 Check_Subtype_Definition
(Etype
(Def_Id
));
2700 -- If the container has a variable indexing aspect, the
2701 -- element is a variable and is modifiable in the loop.
2703 if Has_Aspect
(Typ
, Aspect_Variable_Indexing
) then
2704 Mutate_Ekind
(Def_Id
, E_Variable
);
2707 -- If the container is a constant, iterating over it
2708 -- requires a Constant_Indexing operation.
2710 if not Is_Variable
(Iter_Name
)
2711 and then not Has_Aspect
(Typ
, Aspect_Constant_Indexing
)
2714 ("iteration over constant container require "
2715 & "constant_indexing aspect", N
);
2717 -- The Iterate function may have an in_out parameter,
2718 -- and a constant container is thus illegal.
2720 elsif Present
(Iterator
)
2721 and then Ekind
(Entity
(Iterator
)) = E_Function
2722 and then Ekind
(First_Formal
(Entity
(Iterator
))) /=
2724 and then not Is_Variable
(Iter_Name
)
2726 Error_Msg_N
("variable container expected", N
);
2729 -- Detect a case where the iterator denotes a component
2730 -- of a mutable object which depends on a discriminant.
2731 -- Note that the iterator may denote a function call in
2732 -- qualified form, in which case this check should not
2735 if Nkind
(Orig_Iter_Name
) = N_Selected_Component
2737 Present
(Entity
(Selector_Name
(Orig_Iter_Name
)))
2739 Ekind
(Entity
(Selector_Name
(Orig_Iter_Name
))) in
2740 E_Component | E_Discriminant
2741 and then Is_Dependent_Component_Of_Mutable_Object
2745 ("container cannot be a discriminant-dependent "
2746 & "component of a mutable object", N
);
2752 -- IN iterator, domain is a range, a call to Iterate function,
2753 -- or an object/actual parameter of an iterator type.
2756 -- If the type of the name is class-wide and its root type is a
2757 -- derived type, the primitive operations (First, Next, etc.) are
2758 -- those inherited by its specific type. Calls to these primitives
2759 -- will be dispatching.
2761 if Is_Class_Wide_Type
(Typ
)
2762 and then Is_Derived_Type
(Etype
(Typ
))
2767 -- For an iteration of the form IN, the name must denote an
2768 -- iterator, typically the result of a call to Iterate. Give a
2769 -- useful error message when the name is a container by itself.
2771 -- The type may be a formal container type, which has to have
2772 -- an Iterable aspect detailing the required primitives.
2774 if Is_Entity_Name
(Original_Node
(Name
(N
)))
2775 and then not Is_Iterator
(Typ
)
2777 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2780 elsif not Has_Aspect
(Typ
, Aspect_Iterator_Element
) then
2782 ("cannot iterate over&", Name
(N
), Typ
);
2785 ("name must be an iterator, not a container", Name
(N
));
2788 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2792 ("\to iterate directly over the elements of a container, "
2793 & "write `of &`", Name
(N
), Original_Node
(Name
(N
)));
2795 -- No point in continuing analysis of iterator spec
2801 -- If the name is a call (typically prefixed) to some Iterate
2802 -- function, it has been rewritten as an object declaration.
2803 -- If that object is a selected component, verify that it is not
2804 -- a component of an unconstrained mutable object.
2806 if Nkind
(Iter_Name
) = N_Identifier
2807 or else (not Expander_Active
and Comes_From_Source
(Iter_Name
))
2810 Orig_Node
: constant Node_Id
:= Original_Node
(Iter_Name
);
2811 Iter_Kind
: constant Node_Kind
:= Nkind
(Orig_Node
);
2815 if Iter_Kind
= N_Selected_Component
then
2816 Obj
:= Prefix
(Orig_Node
);
2818 elsif Iter_Kind
= N_Function_Call
then
2819 Obj
:= First_Actual
(Orig_Node
);
2821 -- If neither, the name comes from source
2827 if Nkind
(Obj
) = N_Selected_Component
2828 and then Is_Dependent_Component_Of_Mutable_Object
(Obj
)
2831 ("container cannot be a discriminant-dependent "
2832 & "component of a mutable object", N
);
2837 -- The result type of Iterate function is the classwide type of
2838 -- the interface parent. We need the specific Cursor type defined
2839 -- in the container package. We obtain it by name for a predefined
2840 -- container, or through the Iterable aspect for a formal one.
2842 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2845 (Parent
(Find_Value_Of_Aspect
(Typ
, Aspect_Iterable
)),
2849 Set_Etype
(Def_Id
, Get_Cursor_Type
(Typ
));
2850 Check_Reverse_Iteration
(Etype
(Iter_Name
));
2856 if Present
(Iterator_Filter
(N
)) then
2857 -- Preanalyze the filter. Expansion will take place when enclosing
2858 -- loop is expanded.
2860 Preanalyze_And_Resolve
(Iterator_Filter
(N
), Standard_Boolean
);
2862 end Analyze_Iterator_Specification
;
2868 -- Note: the semantic work required for analyzing labels (setting them as
2869 -- reachable) was done in a prepass through the statements in the block,
2870 -- so that forward gotos would be properly handled. See Analyze_Statements
2871 -- for further details. The only processing required here is to deal with
2872 -- optimizations that depend on an assumption of sequential control flow,
2873 -- since of course the occurrence of a label breaks this assumption.
2875 procedure Analyze_Label
(N
: Node_Id
) is
2876 pragma Warnings
(Off
, N
);
2878 Kill_Current_Values
;
2881 ------------------------------------------
2882 -- Analyze_Loop_Parameter_Specification --
2883 ------------------------------------------
2885 procedure Analyze_Loop_Parameter_Specification
(N
: Node_Id
) is
2886 Loop_Nod
: constant Node_Id
:= Parent
(Parent
(N
));
2888 procedure Check_Controlled_Array_Attribute
(DS
: Node_Id
);
2889 -- If the bounds are given by a 'Range reference on a function call
2890 -- that returns a controlled array, introduce an explicit declaration
2891 -- to capture the bounds, so that the function result can be finalized
2892 -- in timely fashion.
2894 procedure Check_Predicate_Use
(T
: Entity_Id
);
2895 -- Diagnose Attempt to iterate through non-static predicate. Note that
2896 -- a type with inherited predicates may have both static and dynamic
2897 -- forms. In this case it is not sufficient to check the static
2898 -- predicate function only, look for a dynamic predicate aspect as well.
2900 procedure Process_Bounds
(R
: Node_Id
);
2901 -- If the iteration is given by a range, create temporaries and
2902 -- assignment statements block to capture the bounds and perform
2903 -- required finalization actions in case a bound includes a function
2904 -- call that uses the temporary stack. We first preanalyze a copy of
2905 -- the range in order to determine the expected type, and analyze and
2906 -- resolve the original bounds.
2908 --------------------------------------
2909 -- Check_Controlled_Array_Attribute --
2910 --------------------------------------
2912 procedure Check_Controlled_Array_Attribute
(DS
: Node_Id
) is
2914 if Nkind
(DS
) = N_Attribute_Reference
2915 and then Is_Entity_Name
(Prefix
(DS
))
2916 and then Ekind
(Entity
(Prefix
(DS
))) = E_Function
2917 and then Is_Array_Type
(Etype
(Entity
(Prefix
(DS
))))
2919 Is_Controlled
(Component_Type
(Etype
(Entity
(Prefix
(DS
)))))
2920 and then Expander_Active
2923 Loc
: constant Source_Ptr
:= Sloc
(N
);
2924 Arr
: constant Entity_Id
:= Etype
(Entity
(Prefix
(DS
)));
2925 Indx
: constant Entity_Id
:=
2926 Base_Type
(Etype
(First_Index
(Arr
)));
2927 Subt
: constant Entity_Id
:= Make_Temporary
(Loc
, 'S');
2932 Make_Subtype_Declaration
(Loc
,
2933 Defining_Identifier
=> Subt
,
2934 Subtype_Indication
=>
2935 Make_Subtype_Indication
(Loc
,
2936 Subtype_Mark
=> New_Occurrence_Of
(Indx
, Loc
),
2938 Make_Range_Constraint
(Loc
, Relocate_Node
(DS
))));
2939 Insert_Before
(Loop_Nod
, Decl
);
2943 Make_Attribute_Reference
(Loc
,
2944 Prefix
=> New_Occurrence_Of
(Subt
, Loc
),
2945 Attribute_Name
=> Attribute_Name
(DS
)));
2950 end Check_Controlled_Array_Attribute
;
2952 -------------------------
2953 -- Check_Predicate_Use --
2954 -------------------------
2956 procedure Check_Predicate_Use
(T
: Entity_Id
) is
2958 -- A predicated subtype is illegal in loops and related constructs
2959 -- if the predicate is not static, or if it is a non-static subtype
2960 -- of a statically predicated subtype.
2962 if Is_Discrete_Type
(T
)
2963 and then Has_Predicates
(T
)
2964 and then (not Has_Static_Predicate
(T
)
2965 or else not Is_Static_Subtype
(T
)
2966 or else Has_Dynamic_Predicate_Aspect
(T
))
2968 -- Seems a confusing message for the case of a static predicate
2969 -- with a non-static subtype???
2971 Bad_Predicated_Subtype_Use
2972 ("cannot use subtype& with non-static predicate for loop "
2973 & "iteration", Discrete_Subtype_Definition
(N
),
2974 T
, Suggest_Static
=> True);
2976 elsif Inside_A_Generic
2977 and then Is_Generic_Formal
(T
)
2978 and then Is_Discrete_Type
(T
)
2980 Set_No_Dynamic_Predicate_On_Actual
(T
);
2982 end Check_Predicate_Use
;
2984 --------------------
2985 -- Process_Bounds --
2986 --------------------
2988 procedure Process_Bounds
(R
: Node_Id
) is
2989 Loc
: constant Source_Ptr
:= Sloc
(N
);
2992 (Original_Bound
: Node_Id
;
2993 Analyzed_Bound
: Node_Id
;
2994 Typ
: Entity_Id
) return Node_Id
;
2995 -- Capture value of bound and return captured value
3002 (Original_Bound
: Node_Id
;
3003 Analyzed_Bound
: Node_Id
;
3004 Typ
: Entity_Id
) return Node_Id
3011 -- If the bound is a constant or an object, no need for a separate
3012 -- declaration. If the bound is the result of previous expansion
3013 -- it is already analyzed and should not be modified. Note that
3014 -- the Bound will be resolved later, if needed, as part of the
3015 -- call to Make_Index (literal bounds may need to be resolved to
3018 if Analyzed
(Original_Bound
) then
3019 return Original_Bound
;
3021 elsif Nkind
(Analyzed_Bound
) in
3022 N_Integer_Literal | N_Character_Literal
3023 or else Is_Entity_Name
(Analyzed_Bound
)
3025 Analyze_And_Resolve
(Original_Bound
, Typ
);
3026 return Original_Bound
;
3028 elsif Inside_Class_Condition_Preanalysis
then
3029 Analyze_And_Resolve
(Original_Bound
, Typ
);
3030 return Original_Bound
;
3033 -- Normally, the best approach is simply to generate a constant
3034 -- declaration that captures the bound. However, there is a nasty
3035 -- case where this is wrong. If the bound is complex, and has a
3036 -- possible use of the secondary stack, we need to generate a
3037 -- separate assignment statement to ensure the creation of a block
3038 -- which will release the secondary stack.
3040 -- We prefer the constant declaration, since it leaves us with a
3041 -- proper trace of the value, useful in optimizations that get rid
3042 -- of junk range checks.
3044 if not Has_Sec_Stack_Call
(Analyzed_Bound
) then
3045 Analyze_And_Resolve
(Original_Bound
, Typ
);
3047 -- Ensure that the bound is valid. This check should not be
3048 -- generated when the range belongs to a quantified expression
3049 -- as the construct is still not expanded into its final form.
3051 if Nkind
(Parent
(R
)) /= N_Loop_Parameter_Specification
3052 or else Nkind
(Parent
(Parent
(R
))) /= N_Quantified_Expression
3054 Ensure_Valid
(Original_Bound
);
3057 Force_Evaluation
(Original_Bound
);
3058 return Original_Bound
;
3061 Id
:= Make_Temporary
(Loc
, 'R', Original_Bound
);
3063 -- Here we make a declaration with a separate assignment
3064 -- statement, and insert before loop header.
3067 Make_Object_Declaration
(Loc
,
3068 Defining_Identifier
=> Id
,
3069 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
));
3072 Make_Assignment_Statement
(Loc
,
3073 Name
=> New_Occurrence_Of
(Id
, Loc
),
3074 Expression
=> Relocate_Node
(Original_Bound
));
3076 Insert_Actions
(Loop_Nod
, New_List
(Decl
, Assign
));
3078 -- Now that this temporary variable is initialized we decorate it
3079 -- as safe-to-reevaluate to inform to the backend that no further
3080 -- asignment will be issued and hence it can be handled as side
3081 -- effect free. Note that this decoration must be done when the
3082 -- assignment has been analyzed because otherwise it will be
3083 -- rejected (see Analyze_Assignment).
3085 Set_Is_Safe_To_Reevaluate
(Id
);
3087 Rewrite
(Original_Bound
, New_Occurrence_Of
(Id
, Loc
));
3089 if Nkind
(Assign
) = N_Assignment_Statement
then
3090 return Expression
(Assign
);
3092 return Original_Bound
;
3096 Hi
: constant Node_Id
:= High_Bound
(R
);
3097 Lo
: constant Node_Id
:= Low_Bound
(R
);
3098 R_Copy
: constant Node_Id
:= New_Copy_Tree
(R
);
3103 -- Start of processing for Process_Bounds
3106 Set_Parent
(R_Copy
, Parent
(R
));
3107 Preanalyze_Range
(R_Copy
);
3108 Typ
:= Etype
(R_Copy
);
3110 -- If the type of the discrete range is Universal_Integer, then the
3111 -- bound's type must be resolved to Integer, and any object used to
3112 -- hold the bound must also have type Integer, unless the literal
3113 -- bounds are constant-folded expressions with a user-defined type.
3115 if Typ
= Universal_Integer
then
3116 if Nkind
(Lo
) = N_Integer_Literal
3117 and then Present
(Etype
(Lo
))
3118 and then Scope
(Etype
(Lo
)) /= Standard_Standard
3122 elsif Nkind
(Hi
) = N_Integer_Literal
3123 and then Present
(Etype
(Hi
))
3124 and then Scope
(Etype
(Hi
)) /= Standard_Standard
3129 Typ
:= Standard_Integer
;
3135 New_Lo
:= One_Bound
(Lo
, Low_Bound
(R_Copy
), Typ
);
3136 New_Hi
:= One_Bound
(Hi
, High_Bound
(R_Copy
), Typ
);
3138 -- Propagate staticness to loop range itself, in case the
3139 -- corresponding subtype is static.
3141 if New_Lo
/= Lo
and then Is_OK_Static_Expression
(New_Lo
) then
3142 Rewrite
(Low_Bound
(R
), New_Copy
(New_Lo
));
3145 if New_Hi
/= Hi
and then Is_OK_Static_Expression
(New_Hi
) then
3146 Rewrite
(High_Bound
(R
), New_Copy
(New_Hi
));
3152 DS
: constant Node_Id
:= Discrete_Subtype_Definition
(N
);
3153 Id
: constant Entity_Id
:= Defining_Identifier
(N
);
3157 -- Start of processing for Analyze_Loop_Parameter_Specification
3162 -- We always consider the loop variable to be referenced, since the loop
3163 -- may be used just for counting purposes.
3165 Generate_Reference
(Id
, N
, ' ');
3167 -- Check for the case of loop variable hiding a local variable (used
3168 -- later on to give a nice warning if the hidden variable is never
3172 H
: constant Entity_Id
:= Homonym
(Id
);
3175 and then Ekind
(H
) = E_Variable
3176 and then Is_Discrete_Type
(Etype
(H
))
3177 and then Enclosing_Dynamic_Scope
(H
) = Enclosing_Dynamic_Scope
(Id
)
3179 Set_Hiding_Loop_Variable
(H
, Id
);
3183 -- Analyze the subtype definition and create temporaries for the bounds.
3184 -- Do not evaluate the range when preanalyzing a quantified expression
3185 -- because bounds expressed as function calls with side effects will be
3186 -- incorrectly replicated.
3188 if Nkind
(DS
) = N_Range
3189 and then Expander_Active
3190 and then Nkind
(Parent
(N
)) /= N_Quantified_Expression
3192 Process_Bounds
(DS
);
3194 -- Either the expander not active or the range of iteration is a subtype
3195 -- indication, an entity, or a function call that yields an aggregate or
3199 DS_Copy
:= New_Copy_Tree
(DS
);
3200 Set_Parent
(DS_Copy
, Parent
(DS
));
3201 Preanalyze_Range
(DS_Copy
);
3203 -- Ada 2012: If the domain of iteration is:
3205 -- a) a function call,
3206 -- b) an identifier that is not a type,
3207 -- c) an attribute reference 'Old (within a postcondition),
3208 -- d) an unchecked conversion or a qualified expression with
3209 -- the proper iterator type.
3211 -- then it is an iteration over a container. It was classified as
3212 -- a loop specification by the parser, and must be rewritten now
3213 -- to activate container iteration. The last case will occur within
3214 -- an expanded inlined call, where the expansion wraps an actual in
3215 -- an unchecked conversion when needed. The expression of the
3216 -- conversion is always an object.
3218 if Nkind
(DS_Copy
) = N_Function_Call
3220 or else (Is_Entity_Name
(DS_Copy
)
3221 and then not Is_Type
(Entity
(DS_Copy
)))
3223 or else (Nkind
(DS_Copy
) = N_Attribute_Reference
3224 and then Attribute_Name
(DS_Copy
) in
3225 Name_Loop_Entry | Name_Old
)
3227 or else Has_Aspect
(Etype
(DS_Copy
), Aspect_Iterable
)
3229 or else Nkind
(DS_Copy
) = N_Unchecked_Type_Conversion
3230 or else (Nkind
(DS_Copy
) = N_Qualified_Expression
3231 and then Is_Iterator
(Etype
(DS_Copy
)))
3233 -- This is an iterator specification. Rewrite it as such and
3234 -- analyze it to capture function calls that may require
3235 -- finalization actions.
3238 I_Spec
: constant Node_Id
:=
3239 Make_Iterator_Specification
(Sloc
(N
),
3240 Defining_Identifier
=> Relocate_Node
(Id
),
3242 Subtype_Indication
=> Empty
,
3243 Reverse_Present
=> Reverse_Present
(N
));
3244 Scheme
: constant Node_Id
:= Parent
(N
);
3247 Set_Iterator_Specification
(Scheme
, I_Spec
);
3248 Set_Loop_Parameter_Specification
(Scheme
, Empty
);
3249 Set_Iterator_Filter
(I_Spec
,
3250 Relocate_Node
(Iterator_Filter
(N
)));
3252 Analyze_Iterator_Specification
(I_Spec
);
3254 -- In a generic context, analyze the original domain of
3255 -- iteration, for name capture.
3257 if not Expander_Active
then
3261 -- Set kind of loop parameter, which may be used in the
3262 -- subsequent analysis of the condition in a quantified
3265 Mutate_Ekind
(Id
, E_Loop_Parameter
);
3269 -- Domain of iteration is not a function call, and is side-effect
3273 -- A quantified expression that appears in a pre/post condition
3274 -- is preanalyzed several times. If the range is given by an
3275 -- attribute reference it is rewritten as a range, and this is
3276 -- done even with expansion disabled. If the type is already set
3277 -- do not reanalyze, because a range with static bounds may be
3278 -- typed Integer by default.
3280 if Nkind
(Parent
(N
)) = N_Quantified_Expression
3281 and then Present
(Etype
(DS
))
3294 -- Some additional checks if we are iterating through a type
3296 if Is_Entity_Name
(DS
)
3297 and then Present
(Entity
(DS
))
3298 and then Is_Type
(Entity
(DS
))
3300 -- The subtype indication may denote the completion of an incomplete
3301 -- type declaration.
3303 if Ekind
(Entity
(DS
)) = E_Incomplete_Type
then
3304 Set_Entity
(DS
, Get_Full_View
(Entity
(DS
)));
3305 Set_Etype
(DS
, Entity
(DS
));
3308 Check_Predicate_Use
(Entity
(DS
));
3311 -- Error if not discrete type
3313 if not Is_Discrete_Type
(Etype
(DS
)) then
3314 Wrong_Type
(DS
, Any_Discrete
);
3315 Set_Etype
(DS
, Any_Type
);
3318 Check_Controlled_Array_Attribute
(DS
);
3320 if Nkind
(DS
) = N_Subtype_Indication
then
3321 Check_Predicate_Use
(Entity
(Subtype_Mark
(DS
)));
3324 if Nkind
(DS
) not in N_Raise_xxx_Error
then
3328 Mutate_Ekind
(Id
, E_Loop_Parameter
);
3330 -- A quantified expression which appears in a pre- or post-condition may
3331 -- be analyzed multiple times. The analysis of the range creates several
3332 -- itypes which reside in different scopes depending on whether the pre-
3333 -- or post-condition has been expanded. Update the type of the loop
3334 -- variable to reflect the proper itype at each stage of analysis.
3336 -- Loop_Nod might not be present when we are preanalyzing a class-wide
3337 -- pre/postcondition since preanalysis occurs in a place unrelated to
3338 -- the actual code and the quantified expression may be the outermost
3339 -- expression of the class-wide condition.
3342 or else Etype
(Id
) = Any_Type
3344 (Present
(Etype
(Id
))
3345 and then Is_Itype
(Etype
(Id
))
3346 and then Present
(Loop_Nod
)
3347 and then Nkind
(Parent
(Loop_Nod
)) = N_Expression_With_Actions
3348 and then Nkind
(Original_Node
(Parent
(Loop_Nod
))) =
3349 N_Quantified_Expression
)
3351 Set_Etype
(Id
, Etype
(DS
));
3354 -- Treat a range as an implicit reference to the type, to inhibit
3355 -- spurious warnings.
3357 Generate_Reference
(Base_Type
(Etype
(DS
)), N
, ' ');
3358 Set_Is_Known_Valid
(Id
, True);
3360 -- The loop is not a declarative part, so the loop variable must be
3361 -- frozen explicitly. Do not freeze while preanalyzing a quantified
3362 -- expression because the freeze node will not be inserted into the
3363 -- tree due to flag Is_Spec_Expression being set.
3365 if Nkind
(Parent
(N
)) /= N_Quantified_Expression
then
3367 Flist
: constant List_Id
:= Freeze_Entity
(Id
, N
);
3369 Insert_Actions
(N
, Flist
);
3373 -- Case where we have a range or a subtype, get type bounds
3375 if Nkind
(DS
) in N_Range | N_Subtype_Indication
3376 and then not Error_Posted
(DS
)
3377 and then Etype
(DS
) /= Any_Type
3378 and then Is_Discrete_Type
(Etype
(DS
))
3383 Null_Range
: Boolean := False;
3386 if Nkind
(DS
) = N_Range
then
3387 L
:= Low_Bound
(DS
);
3388 H
:= High_Bound
(DS
);
3391 Type_Low_Bound
(Underlying_Type
(Etype
(Subtype_Mark
(DS
))));
3393 Type_High_Bound
(Underlying_Type
(Etype
(Subtype_Mark
(DS
))));
3396 -- Check for null or possibly null range and issue warning. We
3397 -- suppress such messages in generic templates and instances,
3398 -- because in practice they tend to be dubious in these cases. The
3399 -- check applies as well to rewritten array element loops where a
3400 -- null range may be detected statically.
3402 if Compile_Time_Compare
(L
, H
, Assume_Valid
=> True) = GT
then
3403 if Compile_Time_Compare
(L
, H
, Assume_Valid
=> False) = GT
then
3404 -- Since we know the range of the loop is always null,
3405 -- set the appropriate flag to remove the loop entirely
3406 -- during expansion.
3408 Set_Is_Null_Loop
(Loop_Nod
);
3412 -- Suppress the warning if inside a generic template or
3413 -- instance, since in practice they tend to be dubious in these
3414 -- cases since they can result from intended parameterization.
3416 if not Inside_A_Generic
and then not In_Instance
then
3418 -- Specialize msg if invalid values could make the loop
3419 -- non-null after all.
3422 if Comes_From_Source
(N
) then
3424 ("??loop range is null, loop will not execute", DS
);
3427 -- Here is where the loop could execute because of
3428 -- invalid values, so issue appropriate message.
3430 elsif Comes_From_Source
(N
) then
3432 ("??loop range may be null, loop may not execute",
3435 ("??can only execute if invalid values are present",
3440 -- In either case, suppress warnings in the body of the loop,
3441 -- since it is likely that these warnings will be inappropriate
3442 -- if the loop never actually executes, which is likely.
3444 Set_Suppress_Loop_Warnings
(Loop_Nod
);
3446 -- The other case for a warning is a reverse loop where the
3447 -- upper bound is the integer literal zero or one, and the
3448 -- lower bound may exceed this value.
3450 -- For example, we have
3452 -- for J in reverse N .. 1 loop
3454 -- In practice, this is very likely to be a case of reversing
3455 -- the bounds incorrectly in the range.
3457 elsif Reverse_Present
(N
)
3458 and then Nkind
(Original_Node
(H
)) = N_Integer_Literal
3460 (Intval
(Original_Node
(H
)) = Uint_0
3462 Intval
(Original_Node
(H
)) = Uint_1
)
3464 -- Lower bound may in fact be known and known not to exceed
3465 -- upper bound (e.g. reverse 0 .. 1) and that's OK.
3467 if Compile_Time_Known_Value
(L
)
3468 and then Expr_Value
(L
) <= Expr_Value
(H
)
3472 -- Otherwise warning is warranted
3475 Error_Msg_N
("??loop range may be null", DS
);
3476 Error_Msg_N
("\??bounds may be wrong way round", DS
);
3480 -- Check if either bound is known to be outside the range of the
3481 -- loop parameter type, this is e.g. the case of a loop from
3482 -- 20..X where the type is 1..19.
3484 -- Such a loop is dubious since either it raises CE or it executes
3485 -- zero times, and that cannot be useful!
3487 if Etype
(DS
) /= Any_Type
3488 and then not Error_Posted
(DS
)
3489 and then Nkind
(DS
) = N_Subtype_Indication
3490 and then Nkind
(Constraint
(DS
)) = N_Range_Constraint
3493 LLo
: constant Node_Id
:=
3494 Low_Bound
(Range_Expression
(Constraint
(DS
)));
3495 LHi
: constant Node_Id
:=
3496 High_Bound
(Range_Expression
(Constraint
(DS
)));
3498 Bad_Bound
: Node_Id
:= Empty
;
3499 -- Suspicious loop bound
3502 -- At this stage L, H are the bounds of the type, and LLo
3503 -- Lhi are the low bound and high bound of the loop.
3505 if Compile_Time_Compare
(LLo
, L
, Assume_Valid
=> True) = LT
3507 Compile_Time_Compare
(LLo
, H
, Assume_Valid
=> True) = GT
3512 if Compile_Time_Compare
(LHi
, L
, Assume_Valid
=> True) = LT
3514 Compile_Time_Compare
(LHi
, H
, Assume_Valid
=> True) = GT
3519 if Present
(Bad_Bound
) then
3521 ("suspicious loop bound out of range of "
3522 & "loop subtype??", Bad_Bound
);
3524 ("\loop executes zero times or raises "
3525 & "Constraint_Error??", Bad_Bound
);
3528 if Compile_Time_Compare
(LLo
, LHi
, Assume_Valid
=> False)
3531 Error_Msg_N
("??constrained range is null",
3534 -- Additional constraints on modular types can be
3535 -- confusing, add more information.
3537 if Ekind
(Etype
(DS
)) = E_Modular_Integer_Subtype
then
3538 Error_Msg_Uint_1
:= Intval
(LLo
);
3539 Error_Msg_Uint_2
:= Intval
(LHi
);
3540 Error_Msg_NE
("\iterator has modular type &, " &
3541 "so the loop has bounds ^ ..^",
3546 Set_Is_Null_Loop
(Loop_Nod
);
3549 -- Suppress other warnings about the body of the loop, as
3550 -- it will never execute.
3551 Set_Suppress_Loop_Warnings
(Loop_Nod
);
3556 -- This declare block is about warnings, if we get an exception while
3557 -- testing for warnings, we simply abandon the attempt silently. This
3558 -- most likely occurs as the result of a previous error, but might
3559 -- just be an obscure case we have missed. In either case, not giving
3560 -- the warning is perfectly acceptable.
3564 -- With debug flag K we will get an exception unless an error
3565 -- has already occurred (useful for debugging).
3567 if Debug_Flag_K
then
3568 Check_Error_Detected
;
3573 if Present
(Iterator_Filter
(N
)) then
3574 Analyze_And_Resolve
(Iterator_Filter
(N
), Standard_Boolean
);
3577 -- A loop parameter cannot be effectively volatile (SPARK RM 7.1.3(4)).
3578 -- This check is relevant only when SPARK_Mode is on as it is not a
3579 -- standard Ada legality check.
3581 if SPARK_Mode
= On
and then Is_Effectively_Volatile
(Id
) then
3582 Error_Msg_N
("loop parameter cannot be volatile", Id
);
3584 end Analyze_Loop_Parameter_Specification
;
3586 ----------------------------
3587 -- Analyze_Loop_Statement --
3588 ----------------------------
3590 procedure Analyze_Loop_Statement
(N
: Node_Id
) is
3592 -- The following exception is raised by routine Prepare_Loop_Statement
3593 -- to avoid further analysis of a transformed loop.
3595 procedure Prepare_Loop_Statement
3597 Stop_Processing
: out Boolean);
3598 -- Determine whether loop statement N with iteration scheme Iter must be
3599 -- transformed prior to analysis, and if so, perform it.
3600 -- If Stop_Processing is set to True, should stop further processing.
3602 ----------------------------
3603 -- Prepare_Loop_Statement --
3604 ----------------------------
3606 procedure Prepare_Loop_Statement
3608 Stop_Processing
: out Boolean)
3610 function Has_Sec_Stack_Default_Iterator
3611 (Cont_Typ
: Entity_Id
) return Boolean;
3612 pragma Inline
(Has_Sec_Stack_Default_Iterator
);
3613 -- Determine whether container type Cont_Typ has a default iterator
3614 -- that requires secondary stack management.
3616 function Is_Sec_Stack_Iteration_Primitive
3617 (Cont_Typ
: Entity_Id
;
3618 Iter_Prim_Nam
: Name_Id
) return Boolean;
3619 pragma Inline
(Is_Sec_Stack_Iteration_Primitive
);
3620 -- Determine whether container type Cont_Typ has an iteration routine
3621 -- described by its name Iter_Prim_Nam that requires secondary stack
3624 function Is_Wrapped_In_Block
(Stmt
: Node_Id
) return Boolean;
3625 pragma Inline
(Is_Wrapped_In_Block
);
3626 -- Determine whether arbitrary statement Stmt is the sole statement
3627 -- wrapped within some block, excluding pragmas.
3629 procedure Prepare_Iterator_Loop
3630 (Iter_Spec
: Node_Id
;
3631 Stop_Processing
: out Boolean);
3632 pragma Inline
(Prepare_Iterator_Loop
);
3633 -- Prepare an iterator loop with iteration specification Iter_Spec
3634 -- for transformation if needed.
3635 -- If Stop_Processing is set to True, should stop further processing.
3637 procedure Prepare_Param_Spec_Loop
3638 (Param_Spec
: Node_Id
;
3639 Stop_Processing
: out Boolean);
3640 pragma Inline
(Prepare_Param_Spec_Loop
);
3641 -- Prepare a discrete loop with parameter specification Param_Spec
3642 -- for transformation if needed.
3643 -- If Stop_Processing is set to True, should stop further processing.
3645 procedure Wrap_Loop_Statement
(Manage_Sec_Stack
: Boolean);
3646 pragma Inline
(Wrap_Loop_Statement
);
3647 -- Wrap loop statement N within a block. Flag Manage_Sec_Stack must
3648 -- be set when the block must mark and release the secondary stack.
3649 -- Should stop further processing after calling this procedure.
3651 ------------------------------------
3652 -- Has_Sec_Stack_Default_Iterator --
3653 ------------------------------------
3655 function Has_Sec_Stack_Default_Iterator
3656 (Cont_Typ
: Entity_Id
) return Boolean
3658 Def_Iter
: constant Node_Id
:=
3659 Find_Value_Of_Aspect
3660 (Cont_Typ
, Aspect_Default_Iterator
);
3664 and then Present
(Etype
(Def_Iter
))
3665 and then Requires_Transient_Scope
(Etype
(Def_Iter
));
3666 end Has_Sec_Stack_Default_Iterator
;
3668 --------------------------------------
3669 -- Is_Sec_Stack_Iteration_Primitive --
3670 --------------------------------------
3672 function Is_Sec_Stack_Iteration_Primitive
3673 (Cont_Typ
: Entity_Id
;
3674 Iter_Prim_Nam
: Name_Id
) return Boolean
3676 Iter_Prim
: constant Entity_Id
:=
3677 Get_Iterable_Type_Primitive
3678 (Cont_Typ
, Iter_Prim_Nam
);
3682 and then Requires_Transient_Scope
(Etype
(Iter_Prim
));
3683 end Is_Sec_Stack_Iteration_Primitive
;
3685 -------------------------
3686 -- Is_Wrapped_In_Block --
3687 -------------------------
3689 function Is_Wrapped_In_Block
(Stmt
: Node_Id
) return Boolean is
3695 Blk_Id
:= Current_Scope
;
3697 -- The current context is a block. Inspect the statements of the
3698 -- block to determine whether it wraps Stmt.
3700 if Ekind
(Blk_Id
) = E_Block
3701 and then Present
(Block_Node
(Blk_Id
))
3704 Handled_Statement_Sequence
(Parent
(Block_Node
(Blk_Id
)));
3706 -- Skip leading pragmas introduced for invariant and predicate
3709 Blk_Stmt
:= First
(Statements
(Blk_HSS
));
3710 while Present
(Blk_Stmt
)
3711 and then Nkind
(Blk_Stmt
) = N_Pragma
3716 return Blk_Stmt
= Stmt
and then No
(Next
(Blk_Stmt
));
3720 end Is_Wrapped_In_Block
;
3722 ---------------------------
3723 -- Prepare_Iterator_Loop --
3724 ---------------------------
3726 procedure Prepare_Iterator_Loop
3727 (Iter_Spec
: Node_Id
;
3728 Stop_Processing
: out Boolean)
3730 Cont_Typ
: Entity_Id
;
3735 Stop_Processing
:= False;
3737 -- The iterator specification has syntactic errors. Transform the
3738 -- loop into an infinite loop in order to safely perform at least
3739 -- some minor analysis. This check must come first.
3741 if Error_Posted
(Iter_Spec
) then
3742 Set_Iteration_Scheme
(N
, Empty
);
3744 Stop_Processing
:= True;
3746 -- Nothing to do when the loop is already wrapped in a block
3748 elsif Is_Wrapped_In_Block
(N
) then
3751 -- Otherwise the iterator loop traverses an array or a container
3752 -- and appears in the form
3754 -- for Def_Id in [reverse] Iterator_Name loop
3755 -- for Def_Id [: Subtyp_Indic] of [reverse] Iterable_Name loop
3758 -- Prepare a copy of the iterated name for preanalysis. The
3759 -- copy is semi inserted into the tree by setting its Parent
3762 Nam
:= Name
(Iter_Spec
);
3763 Nam_Copy
:= New_Copy_Tree
(Nam
);
3764 Set_Parent
(Nam_Copy
, Parent
(Nam
));
3766 -- Determine what the loop is iterating on
3768 Preanalyze_Range
(Nam_Copy
);
3769 Cont_Typ
:= Etype
(Nam_Copy
);
3771 -- The iterator loop is traversing an array. This case does not
3772 -- require any transformation.
3774 if Is_Array_Type
(Cont_Typ
) then
3777 -- Otherwise unconditionally wrap the loop statement within
3778 -- a block. The expansion of iterator loops may relocate the
3779 -- iterator outside the loop, thus "leaking" its entity into
3780 -- the enclosing scope. Wrapping the loop statement allows
3781 -- for multiple iterator loops using the same iterator name
3782 -- to coexist within the same scope.
3784 -- The block must manage the secondary stack when the iterator
3785 -- loop is traversing a container using either
3787 -- * A default iterator obtained on the secondary stack
3789 -- * Call to Iterate where the iterator is returned on the
3792 -- * Combination of First, Next, and Has_Element where the
3793 -- first two return a cursor on the secondary stack.
3797 (Manage_Sec_Stack
=>
3798 Has_Sec_Stack_Default_Iterator
(Cont_Typ
)
3799 or else Has_Sec_Stack_Call
(Nam_Copy
)
3800 or else Is_Sec_Stack_Iteration_Primitive
3801 (Cont_Typ
, Name_First
)
3802 or else Is_Sec_Stack_Iteration_Primitive
3803 (Cont_Typ
, Name_Next
));
3804 Stop_Processing
:= True;
3807 end Prepare_Iterator_Loop
;
3809 -----------------------------
3810 -- Prepare_Param_Spec_Loop --
3811 -----------------------------
3813 procedure Prepare_Param_Spec_Loop
3814 (Param_Spec
: Node_Id
;
3815 Stop_Processing
: out Boolean)
3821 Rng_Typ
: Entity_Id
;
3824 Stop_Processing
:= False;
3825 Rng
:= Discrete_Subtype_Definition
(Param_Spec
);
3827 -- Nothing to do when the loop is already wrapped in a block
3829 if Is_Wrapped_In_Block
(N
) then
3832 -- The parameter specification appears in the form
3834 -- for Def_Id in Subtype_Mark Constraint loop
3836 elsif Nkind
(Rng
) = N_Subtype_Indication
3837 and then Nkind
(Range_Expression
(Constraint
(Rng
))) = N_Range
3839 Rng
:= Range_Expression
(Constraint
(Rng
));
3841 -- Preanalyze the bounds of the range constraint, setting
3842 -- parent fields to associate the copied bounds with the range,
3843 -- allowing proper tree climbing during preanalysis.
3845 Low
:= New_Copy_Tree
(Low_Bound
(Rng
));
3846 High
:= New_Copy_Tree
(High_Bound
(Rng
));
3848 Set_Parent
(Low
, Rng
);
3849 Set_Parent
(High
, Rng
);
3854 -- The bounds contain at least one function call that returns
3855 -- on the secondary stack. Note that the loop must be wrapped
3856 -- only when such a call exists.
3858 if Has_Sec_Stack_Call
(Low
) or else Has_Sec_Stack_Call
(High
)
3860 Wrap_Loop_Statement
(Manage_Sec_Stack
=> True);
3861 Stop_Processing
:= True;
3864 -- Otherwise the parameter specification appears in the form
3866 -- for Def_Id in Range loop
3869 -- Prepare a copy of the discrete range for preanalysis. The
3870 -- copy is semi inserted into the tree by setting its Parent
3873 Rng_Copy
:= New_Copy_Tree
(Rng
);
3874 Set_Parent
(Rng_Copy
, Parent
(Rng
));
3876 -- Determine what the loop is iterating on
3878 Preanalyze_Range
(Rng_Copy
);
3879 Rng_Typ
:= Etype
(Rng_Copy
);
3881 -- Wrap the loop statement within a block in order to manage
3882 -- the secondary stack when the discrete range is
3884 -- * Either a Forward_Iterator or a Reverse_Iterator
3886 -- * Function call whose return type requires finalization
3889 -- ??? it is unclear why using Has_Sec_Stack_Call directly on
3890 -- the discrete range causes the freeze node of an itype to be
3891 -- in the wrong scope in complex assertion expressions.
3893 if Is_Iterator
(Rng_Typ
)
3894 or else (Nkind
(Rng_Copy
) = N_Function_Call
3895 and then Needs_Finalization
(Rng_Typ
))
3897 Wrap_Loop_Statement
(Manage_Sec_Stack
=> True);
3898 Stop_Processing
:= True;
3901 end Prepare_Param_Spec_Loop
;
3903 -------------------------
3904 -- Wrap_Loop_Statement --
3905 -------------------------
3907 procedure Wrap_Loop_Statement
(Manage_Sec_Stack
: Boolean) is
3908 Loc
: constant Source_Ptr
:= Sloc
(N
);
3915 Make_Block_Statement
(Loc
,
3916 Declarations
=> New_List
,
3917 Handled_Statement_Sequence
=>
3918 Make_Handled_Sequence_Of_Statements
(Loc
,
3919 Statements
=> New_List
(Relocate_Node
(N
))));
3921 Add_Block_Identifier
(Blk
, Blk_Id
);
3922 Set_Uses_Sec_Stack
(Blk_Id
, Manage_Sec_Stack
);
3926 end Wrap_Loop_Statement
;
3930 Iter_Spec
: constant Node_Id
:= Iterator_Specification
(Iter
);
3931 Param_Spec
: constant Node_Id
:= Loop_Parameter_Specification
(Iter
);
3933 -- Start of processing for Prepare_Loop_Statement
3936 Stop_Processing
:= False;
3938 if Present
(Iter_Spec
) then
3939 Prepare_Iterator_Loop
(Iter_Spec
, Stop_Processing
);
3941 elsif Present
(Param_Spec
) then
3942 Prepare_Param_Spec_Loop
(Param_Spec
, Stop_Processing
);
3944 end Prepare_Loop_Statement
;
3946 -- Local declarations
3948 Id
: constant Node_Id
:= Identifier
(N
);
3949 Iter
: constant Node_Id
:= Iteration_Scheme
(N
);
3950 Loc
: constant Source_Ptr
:= Sloc
(N
);
3954 -- Start of processing for Analyze_Loop_Statement
3957 if Present
(Id
) then
3959 -- Make name visible, e.g. for use in exit statements. Loop labels
3960 -- are always considered to be referenced.
3965 -- Guard against serious error (typically, a scope mismatch when
3966 -- semantic analysis is requested) by creating loop entity to
3967 -- continue analysis.
3970 if Total_Errors_Detected
/= 0 then
3971 Ent
:= New_Internal_Entity
(E_Loop
, Current_Scope
, Loc
, 'L');
3973 raise Program_Error
;
3976 -- Verify that the loop name is hot hidden by an unrelated
3977 -- declaration in an inner scope.
3979 elsif Ekind
(Ent
) /= E_Label
and then Ekind
(Ent
) /= E_Loop
then
3980 Error_Msg_Sloc
:= Sloc
(Ent
);
3981 Error_Msg_N
("implicit label declaration for & is hidden#", Id
);
3983 if Present
(Homonym
(Ent
))
3984 and then Ekind
(Homonym
(Ent
)) = E_Label
3986 Set_Entity
(Id
, Ent
);
3987 Mutate_Ekind
(Ent
, E_Loop
);
3991 Generate_Reference
(Ent
, N
, ' ');
3992 Generate_Definition
(Ent
);
3994 -- If we found a label, mark its type. If not, ignore it, since it
3995 -- means we have a conflicting declaration, which would already
3996 -- have been diagnosed at declaration time. Set Label_Construct
3997 -- of the implicit label declaration, which is not created by the
3998 -- parser for generic units.
4000 if Ekind
(Ent
) = E_Label
then
4001 Reinit_Field_To_Zero
(Ent
, F_Enclosing_Scope
);
4002 Reinit_Field_To_Zero
(Ent
, F_Reachable
);
4003 Mutate_Ekind
(Ent
, E_Loop
);
4005 if Nkind
(Parent
(Ent
)) = N_Implicit_Label_Declaration
then
4006 Set_Label_Construct
(Parent
(Ent
), N
);
4011 -- Case of no identifier present. Create one and attach it to the
4012 -- loop statement for use as a scope and as a reference for later
4013 -- expansions. Indicate that the label does not come from source,
4014 -- and attach it to the loop statement so it is part of the tree,
4015 -- even without a full declaration.
4018 Ent
:= New_Internal_Entity
(E_Loop
, Current_Scope
, Loc
, 'L');
4019 Set_Etype
(Ent
, Standard_Void_Type
);
4020 Set_Identifier
(N
, New_Occurrence_Of
(Ent
, Loc
));
4021 Set_Parent
(Ent
, N
);
4022 Set_Has_Created_Identifier
(N
);
4025 -- Determine whether the loop statement must be transformed prior to
4026 -- analysis, and if so, perform it. This early modification is needed
4029 -- * The loop has an erroneous iteration scheme. In this case the
4030 -- loop is converted into an infinite loop in order to perform
4033 -- * The loop is an Ada 2012 iterator loop. In this case the loop is
4034 -- wrapped within a block to provide a local scope for the iterator.
4035 -- If the iterator specification requires the secondary stack in any
4036 -- way, the block is marked in order to manage it.
4038 -- * The loop is using a parameter specification where the discrete
4039 -- range requires the secondary stack. In this case the loop is
4040 -- wrapped within a block in order to manage the secondary stack.
4042 -- ??? This overlooks finalization: the loop may leave the secondary
4043 -- stack untouched, but its iterator or discrete range may need
4044 -- finalization, in which case the block is also required. Therefore
4045 -- the criterion must be based on Sem_Util.Requires_Transient_Scope,
4046 -- which happens to be what is currently implemented.
4048 if Present
(Iter
) then
4050 Stop_Processing
: Boolean;
4052 Prepare_Loop_Statement
(Iter
, Stop_Processing
);
4054 if Stop_Processing
then
4060 -- Kill current values on entry to loop, since statements in the body of
4061 -- the loop may have been executed before the loop is entered. Similarly
4062 -- we kill values after the loop, since we do not know that the body of
4063 -- the loop was executed.
4065 Kill_Current_Values
;
4067 Analyze_Iteration_Scheme
(Iter
);
4069 -- Check for following case which merits a warning if the type E of is
4070 -- a multi-dimensional array (and no explicit subscript ranges present).
4076 and then Present
(Loop_Parameter_Specification
(Iter
))
4079 LPS
: constant Node_Id
:= Loop_Parameter_Specification
(Iter
);
4080 DSD
: constant Node_Id
:=
4081 Original_Node
(Discrete_Subtype_Definition
(LPS
));
4083 if Nkind
(DSD
) = N_Attribute_Reference
4084 and then Attribute_Name
(DSD
) = Name_Range
4085 and then No
(Expressions
(DSD
))
4088 Typ
: constant Entity_Id
:= Etype
(Prefix
(DSD
));
4090 if Is_Array_Type
(Typ
)
4091 and then Number_Dimensions
(Typ
) > 1
4092 and then Nkind
(Parent
(N
)) = N_Loop_Statement
4093 and then Present
(Iteration_Scheme
(Parent
(N
)))
4096 OIter
: constant Node_Id
:=
4097 Iteration_Scheme
(Parent
(N
));
4098 OLPS
: constant Node_Id
:=
4099 Loop_Parameter_Specification
(OIter
);
4100 ODSD
: constant Node_Id
:=
4101 Original_Node
(Discrete_Subtype_Definition
(OLPS
));
4103 if Nkind
(ODSD
) = N_Attribute_Reference
4104 and then Attribute_Name
(ODSD
) = Name_Range
4105 and then No
(Expressions
(ODSD
))
4106 and then Etype
(Prefix
(ODSD
)) = Typ
4108 Error_Msg_Sloc
:= Sloc
(ODSD
);
4110 ("inner range same as outer range#??", DSD
);
4119 -- Analyze the statements of the body except in the case of an Ada 2012
4120 -- iterator with the expander active. In this case the expander will do
4121 -- a rewrite of the loop into a while loop. We will then analyze the
4122 -- loop body when we analyze this while loop.
4124 -- We need to do this delay because if the container is for indefinite
4125 -- types the actual subtype of the components will only be determined
4126 -- when the cursor declaration is analyzed.
4128 -- If the expander is not active then we want to analyze the loop body
4129 -- now even in the Ada 2012 iterator case, since the rewriting will not
4130 -- be done. Insert the loop variable in the current scope, if not done
4131 -- when analysing the iteration scheme. Set its kind properly to detect
4132 -- improper uses in the loop body.
4134 -- In GNATprove mode, we do one of the above depending on the kind of
4135 -- loop. If it is an iterator over an array, then we do not analyze the
4136 -- loop now. We will analyze it after it has been rewritten by the
4137 -- special SPARK expansion which is activated in GNATprove mode. We need
4138 -- to do this so that other expansions that should occur in GNATprove
4139 -- mode take into account the specificities of the rewritten loop, in
4140 -- particular the introduction of a renaming (which needs to be
4143 -- In other cases in GNATprove mode then we want to analyze the loop
4144 -- body now, since no rewriting will occur. Within a generic the
4145 -- GNATprove mode is irrelevant, we must analyze the generic for
4146 -- non-local name capture.
4149 and then Present
(Iterator_Specification
(Iter
))
4152 and then Is_Iterator_Over_Array
(Iterator_Specification
(Iter
))
4153 and then not Inside_A_Generic
4157 elsif not Expander_Active
then
4159 I_Spec
: constant Node_Id
:= Iterator_Specification
(Iter
);
4160 Id
: constant Entity_Id
:= Defining_Identifier
(I_Spec
);
4163 if Scope
(Id
) /= Current_Scope
then
4167 -- In an element iterator, the loop parameter is a variable if
4168 -- the domain of iteration (container or array) is a variable.
4170 if not Of_Present
(I_Spec
)
4171 or else not Is_Variable
(Name
(I_Spec
))
4173 Mutate_Ekind
(Id
, E_Loop_Parameter
);
4177 Analyze_Statements
(Statements
(N
));
4181 -- Pre-Ada2012 for-loops and while loops
4183 Analyze_Statements
(Statements
(N
));
4186 -- If the loop has no side effects, mark it for removal.
4188 if Side_Effect_Free_Loop
(N
) then
4189 Set_Is_Null_Loop
(N
);
4192 -- When the iteration scheme of a loop contains attribute 'Loop_Entry,
4193 -- the loop is transformed into a conditional block. Retrieve the loop.
4197 if Subject_To_Loop_Entry_Attributes
(Stmt
) then
4198 Stmt
:= Find_Loop_In_Conditional_Block
(Stmt
);
4201 -- Finish up processing for the loop. We kill all current values, since
4202 -- in general we don't know if the statements in the loop have been
4203 -- executed. We could do a bit better than this with a loop that we
4204 -- know will execute at least once, but it's not worth the trouble and
4205 -- the front end is not in the business of flow tracing.
4207 Process_End_Label
(Stmt
, 'e', Ent
);
4209 Kill_Current_Values
;
4211 -- Check for infinite loop. Skip check for generated code, since it
4212 -- justs waste time and makes debugging the routine called harder.
4214 -- Note that we have to wait till the body of the loop is fully analyzed
4215 -- before making this call, since Check_Infinite_Loop_Warning relies on
4216 -- being able to use semantic visibility information to find references.
4218 if Comes_From_Source
(Stmt
) then
4219 Check_Infinite_Loop_Warning
(Stmt
);
4222 -- Code after loop is unreachable if the loop has no WHILE or FOR and
4223 -- contains no EXIT statements within the body of the loop.
4225 if No
(Iter
) and then not Has_Exit
(Ent
) then
4226 Check_Unreachable_Code
(Stmt
);
4228 end Analyze_Loop_Statement
;
4230 ----------------------------
4231 -- Analyze_Null_Statement --
4232 ----------------------------
4234 -- Note: the semantics of the null statement is implemented by a single
4235 -- null statement, too bad everything isn't as simple as this.
4237 procedure Analyze_Null_Statement
(N
: Node_Id
) is
4238 pragma Warnings
(Off
, N
);
4241 end Analyze_Null_Statement
;
4243 -------------------------
4244 -- Analyze_Target_Name --
4245 -------------------------
4247 procedure Analyze_Target_Name
(N
: Node_Id
) is
4248 procedure Report_Error
;
4249 -- Complain about illegal use of target_name and rewrite it into unknown
4256 procedure Report_Error
is
4259 ("must appear in the right-hand side of an assignment statement",
4261 Rewrite
(N
, New_Occurrence_Of
(Any_Id
, Sloc
(N
)));
4264 -- Start of processing for Analyze_Target_Name
4267 -- A target name has the type of the left-hand side of the enclosing
4270 -- First, verify that the context is the right-hand side of an
4271 -- assignment statement.
4273 if No
(Current_Assignment
) then
4279 Current
: Node_Id
:= N
;
4280 Context
: Node_Id
:= Parent
(N
);
4282 while Present
(Context
) loop
4284 -- Check if target_name appears in the expression of the enclosing
4287 if Nkind
(Context
) = N_Assignment_Statement
then
4288 if Current
= Expression
(Context
) then
4289 pragma Assert
(Context
= Current_Assignment
);
4290 Set_Etype
(N
, Etype
(Name
(Current_Assignment
)));
4296 -- Prevent the search from going too far
4298 elsif Is_Body_Or_Package_Declaration
(Context
) then
4304 Context
:= Parent
(Context
);
4309 end Analyze_Target_Name
;
4311 ------------------------
4312 -- Analyze_Statements --
4313 ------------------------
4315 procedure Analyze_Statements
(L
: List_Id
) is
4320 -- The labels declared in the statement list are reachable from
4321 -- statements in the list. We do this as a prepass so that any goto
4322 -- statement will be properly flagged if its target is not reachable.
4323 -- This is not required, but is nice behavior.
4326 while Present
(S
) loop
4327 if Nkind
(S
) = N_Label
then
4328 Analyze
(Identifier
(S
));
4329 Lab
:= Entity
(Identifier
(S
));
4331 -- If we found a label mark it as reachable
4333 if Ekind
(Lab
) = E_Label
then
4334 Generate_Definition
(Lab
);
4335 Set_Reachable
(Lab
);
4337 if Nkind
(Parent
(Lab
)) = N_Implicit_Label_Declaration
then
4338 Set_Label_Construct
(Parent
(Lab
), S
);
4341 -- If we failed to find a label, it means the implicit declaration
4342 -- of the label was hidden. A for-loop parameter can do this to
4343 -- a label with the same name inside the loop, since the implicit
4344 -- label declaration is in the innermost enclosing body or block
4348 Error_Msg_Sloc
:= Sloc
(Lab
);
4350 ("implicit label declaration for & is hidden#",
4358 -- Perform semantic analysis on all statements
4360 Conditional_Statements_Begin
;
4363 while Present
(S
) loop
4366 -- Remove dimension in all statements
4368 Remove_Dimension_In_Statement
(S
);
4372 Conditional_Statements_End
;
4374 -- Make labels unreachable. Visibility is not sufficient, because labels
4375 -- in one if-branch for example are not reachable from the other branch,
4376 -- even though their declarations are in the enclosing declarative part.
4379 while Present
(S
) loop
4380 if Nkind
(S
) = N_Label
4381 and then Ekind
(Entity
(Identifier
(S
))) = E_Label
4383 Set_Reachable
(Entity
(Identifier
(S
)), False);
4388 end Analyze_Statements
;
4390 ----------------------------
4391 -- Check_Unreachable_Code --
4392 ----------------------------
4394 procedure Check_Unreachable_Code
(N
: Node_Id
) is
4396 function Is_Simple_Case
(N
: Node_Id
) return Boolean;
4397 -- N is the condition of an if statement. True if N is simple enough
4398 -- that we should not set Unblocked_Exit_Count in the special case
4401 --------------------
4402 -- Is_Simple_Case --
4403 --------------------
4405 function Is_Simple_Case
(N
: Node_Id
) return Boolean is
4408 Is_Trivial_Boolean
(N
)
4410 (Comes_From_Source
(N
)
4411 and then Is_Static_Expression
(N
)
4412 and then Nkind
(N
) in N_Identifier | N_Expanded_Name
4413 and then Ekind
(Entity
(N
)) = E_Constant
)
4416 and then Nkind
(Original_Node
(N
)) = N_Op_Not
4417 and then Is_Simple_Case
(Right_Opnd
(Original_Node
(N
))));
4420 Error_Node
: Node_Id
;
4425 if Comes_From_Source
(N
) then
4426 Nxt
:= Original_Node
(Next
(N
));
4428 -- Skip past pragmas
4430 while Nkind
(Nxt
) = N_Pragma
loop
4431 Nxt
:= Original_Node
(Next
(Nxt
));
4434 -- If a label follows us, then we never have dead code, since someone
4435 -- could branch to the label, so we just ignore it.
4437 if Nkind
(Nxt
) = N_Label
then
4440 -- Otherwise see if we have a real statement following us
4442 elsif Comes_From_Source
(Nxt
)
4443 and then Is_Statement
(Nxt
)
4445 -- Special very annoying exception. Ada RM 6.5(5) annoyingly
4446 -- requires functions to have at least one return statement, so
4447 -- don't complain about a simple return that follows a raise or a
4448 -- call to procedure with No_Return.
4450 if not (Present
(Current_Subprogram
)
4451 and then Ekind
(Current_Subprogram
) = E_Function
4452 and then (Nkind
(N
) in N_Raise_Statement
4454 (Nkind
(N
) = N_Procedure_Call_Statement
4455 and then Is_Entity_Name
(Name
(N
))
4456 and then Present
(Entity
(Name
(N
)))
4457 and then No_Return
(Entity
(Name
(N
)))))
4458 and then Nkind
(Nxt
) = N_Simple_Return_Statement
)
4460 -- The rather strange shenanigans with the warning message
4461 -- here reflects the fact that Kill_Dead_Code is very good at
4462 -- removing warnings in deleted code, and this is one warning
4463 -- we would prefer NOT to have removed.
4467 -- If we have unreachable code, analyze and remove the
4468 -- unreachable code, since it is useless and we don't want
4469 -- to generate junk warnings.
4471 -- We skip this step if we are not in code generation mode.
4473 -- This is the one case where we remove dead code in the
4474 -- semantics as opposed to the expander, and we do not want
4475 -- to remove code if we are not in code generation mode, since
4476 -- this messes up the tree or loses useful information for
4477 -- analysis tools such as CodePeer.
4479 -- Note that one might react by moving the whole circuit to
4480 -- exp_ch5, but then we lose the warning in -gnatc mode.
4482 if Operating_Mode
= Generate_Code
then
4485 Del
: constant Node_Id
:= Next
(N
);
4486 -- Node to be possibly deleted
4488 -- Quit deleting when we have nothing more to delete
4489 -- or if we hit a label (since someone could transfer
4490 -- control to a label, so we should not delete it).
4492 exit when No
(Del
) or else Nkind
(Del
) = N_Label
;
4494 -- Statement/declaration is to be deleted
4497 Kill_Dead_Code
(Del
);
4502 -- If this is a function, we add "raise Program_Error;",
4503 -- because otherwise, we will get incorrect warnings about
4504 -- falling off the end of the function.
4507 Subp
: constant Entity_Id
:= Current_Subprogram
;
4509 if Present
(Subp
) and then Ekind
(Subp
) = E_Function
then
4510 Insert_After_And_Analyze
(N
,
4511 Make_Raise_Program_Error
(Sloc
(Error_Node
),
4512 Reason
=> PE_Missing_Return
));
4518 -- Suppress the warning in instances, because a statement can
4519 -- be unreachable in some instances but not others.
4521 if not In_Instance
then
4522 Error_Msg_N
("??unreachable code!", Error_Node
);
4526 -- If the unconditional transfer of control instruction is the
4527 -- last statement of a sequence, then see if our parent is one of
4528 -- the constructs for which we count unblocked exits, and if so,
4529 -- adjust the count.
4534 -- Statements in THEN part or ELSE part of IF statement
4536 if Nkind
(P
) = N_If_Statement
then
4539 -- Statements in ELSIF part of an IF statement
4541 elsif Nkind
(P
) = N_Elsif_Part
then
4543 pragma Assert
(Nkind
(P
) = N_If_Statement
);
4545 -- Statements in CASE statement alternative
4547 elsif Nkind
(P
) = N_Case_Statement_Alternative
then
4549 pragma Assert
(Nkind
(P
) = N_Case_Statement
);
4551 -- Statements in body of block
4553 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
4554 and then Nkind
(Parent
(P
)) = N_Block_Statement
4556 -- The original loop is now placed inside a block statement
4557 -- due to the expansion of attribute 'Loop_Entry. Return as
4558 -- this is not a "real" block for the purposes of exit
4561 if Nkind
(N
) = N_Loop_Statement
4562 and then Subject_To_Loop_Entry_Attributes
(N
)
4567 -- Statements in exception handler in a block
4569 elsif Nkind
(P
) = N_Exception_Handler
4570 and then Nkind
(Parent
(P
)) = N_Handled_Sequence_Of_Statements
4571 and then Nkind
(Parent
(Parent
(P
))) = N_Block_Statement
4575 -- None of these cases, so return
4581 -- This was one of the cases we are looking for (i.e. the parent
4582 -- construct was IF, CASE or block). In most cases, we simply
4583 -- decrement the count. However, if the parent is something like:
4586 -- raise ...; -- or some other jump
4589 -- where cond is an expression that is known-true at compile time,
4590 -- we can treat that as just the jump -- i.e. anything following
4591 -- the if statement is unreachable. We don't do this for simple
4592 -- cases like "if True" or "if Debug_Flag", because that causes
4593 -- too many warnings.
4595 if Nkind
(P
) = N_If_Statement
4596 and then Present
(Then_Statements
(P
))
4597 and then No
(Elsif_Parts
(P
))
4598 and then No
(Else_Statements
(P
))
4599 and then Is_OK_Static_Expression
(Condition
(P
))
4600 and then Is_True
(Expr_Value
(Condition
(P
)))
4601 and then not Is_Simple_Case
(Condition
(P
))
4603 pragma Assert
(Unblocked_Exit_Count
= 2);
4604 Unblocked_Exit_Count
:= 0;
4606 Unblocked_Exit_Count
:= Unblocked_Exit_Count
- 1;
4610 end Check_Unreachable_Code
;
4612 ------------------------
4613 -- Has_Sec_Stack_Call --
4614 ------------------------
4616 function Has_Sec_Stack_Call
(N
: Node_Id
) return Boolean is
4617 function Check_Call
(N
: Node_Id
) return Traverse_Result
;
4618 -- Check if N is a function call which uses the secondary stack
4624 function Check_Call
(N
: Node_Id
) return Traverse_Result
is
4630 if Nkind
(N
) = N_Function_Call
then
4633 -- Obtain the subprogram being invoked
4636 if Nkind
(Nam
) = N_Explicit_Dereference
then
4637 Nam
:= Prefix
(Nam
);
4639 elsif Nkind
(Nam
) = N_Selected_Component
then
4640 Nam
:= Selector_Name
(Nam
);
4647 Subp
:= Entity
(Nam
);
4649 if Present
(Subp
) then
4650 Typ
:= Etype
(Subp
);
4652 if Requires_Transient_Scope
(Typ
) then
4655 elsif Sec_Stack_Needed_For_Return
(Subp
) then
4661 -- Continue traversing the tree
4666 function Check_Calls
is new Traverse_Func
(Check_Call
);
4668 -- Start of processing for Has_Sec_Stack_Call
4671 return Check_Calls
(N
) = Abandon
;
4672 end Has_Sec_Stack_Call
;
4674 ----------------------
4675 -- Preanalyze_Range --
4676 ----------------------
4678 procedure Preanalyze_Range
(R_Copy
: Node_Id
) is
4679 Save_Analysis
: constant Boolean := Full_Analysis
;
4683 Full_Analysis
:= False;
4684 Expander_Mode_Save_And_Set
(False);
4686 -- In addition to the above we must explicitly suppress the generation
4687 -- of freeze nodes that might otherwise be generated during resolution
4688 -- of the range (e.g. if given by an attribute that will freeze its
4691 Set_Must_Not_Freeze
(R_Copy
);
4693 if Nkind
(R_Copy
) = N_Attribute_Reference
then
4694 Set_Must_Not_Freeze
(Prefix
(R_Copy
));
4699 if Nkind
(R_Copy
) in N_Subexpr
and then Is_Overloaded
(R_Copy
) then
4701 -- Apply preference rules for range of predefined integer types, or
4702 -- check for array or iterable construct for "of" iterator, or
4703 -- diagnose true ambiguity.
4708 Found
: Entity_Id
:= Empty
;
4711 Get_First_Interp
(R_Copy
, I
, It
);
4712 while Present
(It
.Typ
) loop
4713 if Is_Discrete_Type
(It
.Typ
) then
4717 if Scope
(Found
) = Standard_Standard
then
4720 elsif Scope
(It
.Typ
) = Standard_Standard
then
4724 -- Both of them are user-defined
4727 ("ambiguous bounds in range of iteration", R_Copy
);
4728 Error_Msg_N
("\possible interpretations:", R_Copy
);
4729 Error_Msg_NE
("\\}", R_Copy
, Found
);
4730 Error_Msg_NE
("\\}", R_Copy
, It
.Typ
);
4735 elsif Nkind
(Parent
(R_Copy
)) = N_Iterator_Specification
4736 and then Of_Present
(Parent
(R_Copy
))
4738 if Is_Array_Type
(It
.Typ
)
4739 or else Has_Aspect
(It
.Typ
, Aspect_Iterator_Element
)
4740 or else Has_Aspect
(It
.Typ
, Aspect_Constant_Indexing
)
4741 or else Has_Aspect
(It
.Typ
, Aspect_Variable_Indexing
)
4745 Set_Etype
(R_Copy
, It
.Typ
);
4748 Error_Msg_N
("ambiguous domain of iteration", R_Copy
);
4753 Get_Next_Interp
(I
, It
);
4758 -- Subtype mark in iteration scheme
4760 if Is_Entity_Name
(R_Copy
) and then Is_Type
(Entity
(R_Copy
)) then
4763 -- Expression in range, or Ada 2012 iterator
4765 elsif Nkind
(R_Copy
) in N_Subexpr
then
4767 Typ
:= Etype
(R_Copy
);
4769 if Is_Discrete_Type
(Typ
) then
4772 -- Check that the resulting object is an iterable container
4774 elsif Has_Aspect
(Typ
, Aspect_Iterator_Element
)
4775 or else Has_Aspect
(Typ
, Aspect_Constant_Indexing
)
4776 or else Has_Aspect
(Typ
, Aspect_Variable_Indexing
)
4780 -- The expression may yield an implicit reference to an iterable
4781 -- container. Insert explicit dereference so that proper type is
4782 -- visible in the loop.
4784 elsif Has_Implicit_Dereference
(Etype
(R_Copy
)) then
4785 Build_Explicit_Dereference
4786 (R_Copy
, Get_Reference_Discriminant
(Etype
(R_Copy
)));
4790 Expander_Mode_Restore
;
4791 Full_Analysis
:= Save_Analysis
;
4792 end Preanalyze_Range
;