1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2017, 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 Einfo
; use Einfo
;
30 with Errout
; use Errout
;
31 with Expander
; use Expander
;
32 with Exp_Ch6
; use Exp_Ch6
;
33 with Exp_Util
; use Exp_Util
;
34 with Freeze
; use Freeze
;
35 with Ghost
; use Ghost
;
37 with Lib
.Xref
; use Lib
.Xref
;
38 with Namet
; use Namet
;
39 with Nlists
; use Nlists
;
40 with Nmake
; use Nmake
;
42 with Restrict
; use Restrict
;
43 with Rident
; use Rident
;
45 with Sem_Aux
; use Sem_Aux
;
46 with Sem_Case
; use Sem_Case
;
47 with Sem_Ch3
; use Sem_Ch3
;
48 with Sem_Ch6
; use Sem_Ch6
;
49 with Sem_Ch8
; use Sem_Ch8
;
50 with Sem_Dim
; use Sem_Dim
;
51 with Sem_Disp
; use Sem_Disp
;
52 with Sem_Elab
; use Sem_Elab
;
53 with Sem_Eval
; use Sem_Eval
;
54 with Sem_Res
; use Sem_Res
;
55 with Sem_Type
; use Sem_Type
;
56 with Sem_Util
; use Sem_Util
;
57 with Sem_Warn
; use Sem_Warn
;
58 with Snames
; use Snames
;
59 with Stand
; use Stand
;
60 with Sinfo
; use Sinfo
;
61 with Targparm
; use Targparm
;
62 with Tbuild
; use Tbuild
;
63 with Uintp
; use Uintp
;
65 package body Sem_Ch5
is
67 Current_Assignment
: Node_Id
:= Empty
;
68 -- This variable holds the node for an assignment that contains target
69 -- names. The corresponding flag has been set by the parser, and when
70 -- set the analysis of the RHS must be done with all expansion disabled,
71 -- because the assignment is reanalyzed after expansion has replaced all
72 -- occurrences of the target name appropriately.
74 Unblocked_Exit_Count
: Nat
:= 0;
75 -- This variable is used when processing if statements, case statements,
76 -- and block statements. It counts the number of exit points that are not
77 -- blocked by unconditional transfer instructions: for IF and CASE, these
78 -- are the branches of the conditional; for a block, they are the statement
79 -- sequence of the block, and the statement sequences of any exception
80 -- handlers that are part of the block. When processing is complete, if
81 -- this count is zero, it means that control cannot fall through the IF,
82 -- CASE or block statement. This is used for the generation of warning
83 -- messages. This variable is recursively saved on entry to processing the
84 -- construct, and restored on exit.
86 procedure Preanalyze_Range
(R_Copy
: Node_Id
);
87 -- Determine expected type of range or domain of iteration of Ada 2012
88 -- loop by analyzing separate copy. Do the analysis and resolution of the
89 -- copy of the bound(s) with expansion disabled, to prevent the generation
90 -- of finalization actions. This prevents memory leaks when the bounds
91 -- contain calls to functions returning controlled arrays or when the
92 -- domain of iteration is a container.
94 ------------------------
95 -- Analyze_Assignment --
96 ------------------------
98 -- WARNING: This routine manages Ghost regions. Return statements must be
99 -- replaced by gotos which jump to the end of the routine and restore the
102 procedure Analyze_Assignment
(N
: Node_Id
) is
103 Lhs
: constant Node_Id
:= Name
(N
);
104 Rhs
: Node_Id
:= Expression
(N
);
106 procedure Diagnose_Non_Variable_Lhs
(N
: Node_Id
);
107 -- N is the node for the left hand side of an assignment, and it is not
108 -- a variable. This routine issues an appropriate diagnostic.
111 -- This is called to kill current value settings of a simple variable
112 -- on the left hand side. We call it if we find any error in analyzing
113 -- the assignment, and at the end of processing before setting any new
114 -- current values in place.
116 procedure Set_Assignment_Type
118 Opnd_Type
: in out Entity_Id
);
119 -- Opnd is either the Lhs or Rhs of the assignment, and Opnd_Type is the
120 -- nominal subtype. This procedure is used to deal with cases where the
121 -- nominal subtype must be replaced by the actual subtype.
123 procedure Transform_BIP_Assignment
(Typ
: Entity_Id
);
124 function Should_Transform_BIP_Assignment
125 (Typ
: Entity_Id
) return Boolean;
126 -- If the right-hand side of an assignment statement is a build-in-place
127 -- call we cannot build in place, so we insert a temp initialized with
128 -- the call, and transform the assignment statement to copy the temp.
129 -- Transform_BIP_Assignment does the tranformation, and
130 -- Should_Transform_BIP_Assignment determines whether we should.
131 -- The same goes for qualified expressions and conversions whose
132 -- operand is such a call.
134 -- This is only for nonlimited types; assignment statements are illegal
135 -- for limited types, but are generated internally for aggregates and
136 -- init procs. These limited-type are not really assignment statements
137 -- -- conceptually, they are initializations, so should not be
140 -- Similarly, for nonlimited types, aggregates and init procs generate
141 -- assignment statements that are really initializations. These are
142 -- marked No_Ctrl_Actions.
144 -------------------------------
145 -- Diagnose_Non_Variable_Lhs --
146 -------------------------------
148 procedure Diagnose_Non_Variable_Lhs
(N
: Node_Id
) is
150 -- Not worth posting another error if left hand side already flagged
151 -- as being illegal in some respect.
153 if Error_Posted
(N
) then
156 -- Some special bad cases of entity names
158 elsif Is_Entity_Name
(N
) then
160 Ent
: constant Entity_Id
:= Entity
(N
);
163 if Ekind
(Ent
) = E_In_Parameter
then
165 ("assignment to IN mode parameter not allowed", N
);
168 -- Renamings of protected private components are turned into
169 -- constants when compiling a protected function. In the case
170 -- of single protected types, the private component appears
173 elsif (Is_Prival
(Ent
)
175 (Ekind
(Current_Scope
) = E_Function
176 or else Ekind
(Enclosing_Dynamic_Scope
177 (Current_Scope
)) = E_Function
))
179 (Ekind
(Ent
) = E_Component
180 and then Is_Protected_Type
(Scope
(Ent
)))
183 ("protected function cannot modify protected object", N
);
186 elsif Ekind
(Ent
) = E_Loop_Parameter
then
187 Error_Msg_N
("assignment to loop parameter not allowed", N
);
192 -- For indexed components, test prefix if it is in array. We do not
193 -- want to recurse for cases where the prefix is a pointer, since we
194 -- may get a message confusing the pointer and what it references.
196 elsif Nkind
(N
) = N_Indexed_Component
197 and then Is_Array_Type
(Etype
(Prefix
(N
)))
199 Diagnose_Non_Variable_Lhs
(Prefix
(N
));
202 -- Another special case for assignment to discriminant
204 elsif Nkind
(N
) = N_Selected_Component
then
205 if Present
(Entity
(Selector_Name
(N
)))
206 and then Ekind
(Entity
(Selector_Name
(N
))) = E_Discriminant
208 Error_Msg_N
("assignment to discriminant not allowed", N
);
211 -- For selection from record, diagnose prefix, but note that again
212 -- we only do this for a record, not e.g. for a pointer.
214 elsif Is_Record_Type
(Etype
(Prefix
(N
))) then
215 Diagnose_Non_Variable_Lhs
(Prefix
(N
));
220 -- If we fall through, we have no special message to issue
222 Error_Msg_N
("left hand side of assignment must be a variable", N
);
223 end Diagnose_Non_Variable_Lhs
;
229 procedure Kill_Lhs
is
231 if Is_Entity_Name
(Lhs
) then
233 Ent
: constant Entity_Id
:= Entity
(Lhs
);
235 if Present
(Ent
) then
236 Kill_Current_Values
(Ent
);
242 -------------------------
243 -- Set_Assignment_Type --
244 -------------------------
246 procedure Set_Assignment_Type
248 Opnd_Type
: in out Entity_Id
)
253 Require_Entity
(Opnd
);
255 -- If the assignment operand is an in-out or out parameter, then we
256 -- get the actual subtype (needed for the unconstrained case). If the
257 -- operand is the actual in an entry declaration, then within the
258 -- accept statement it is replaced with a local renaming, which may
259 -- also have an actual subtype.
261 if Is_Entity_Name
(Opnd
)
262 and then (Ekind
(Entity
(Opnd
)) = E_Out_Parameter
263 or else Ekind_In
(Entity
(Opnd
),
265 E_Generic_In_Out_Parameter
)
267 (Ekind
(Entity
(Opnd
)) = E_Variable
268 and then Nkind
(Parent
(Entity
(Opnd
))) =
269 N_Object_Renaming_Declaration
270 and then Nkind
(Parent
(Parent
(Entity
(Opnd
)))) =
273 Opnd_Type
:= Get_Actual_Subtype
(Opnd
);
275 -- If assignment operand is a component reference, then we get the
276 -- actual subtype of the component for the unconstrained case.
278 elsif Nkind_In
(Opnd
, N_Selected_Component
, N_Explicit_Dereference
)
279 and then not Is_Unchecked_Union
(Opnd_Type
)
281 Decl
:= Build_Actual_Subtype_Of_Component
(Opnd_Type
, Opnd
);
283 if Present
(Decl
) then
284 Insert_Action
(N
, Decl
);
285 Mark_Rewrite_Insertion
(Decl
);
287 Opnd_Type
:= Defining_Identifier
(Decl
);
288 Set_Etype
(Opnd
, Opnd_Type
);
289 Freeze_Itype
(Opnd_Type
, N
);
291 elsif Is_Constrained
(Etype
(Opnd
)) then
292 Opnd_Type
:= Etype
(Opnd
);
295 -- For slice, use the constrained subtype created for the slice
297 elsif Nkind
(Opnd
) = N_Slice
then
298 Opnd_Type
:= Etype
(Opnd
);
300 end Set_Assignment_Type
;
302 -------------------------------------
303 -- Should_Transform_BIP_Assignment --
304 -------------------------------------
306 function Should_Transform_BIP_Assignment
307 (Typ
: Entity_Id
) return Boolean
313 and then not Is_Limited_View
(Typ
)
314 and then Is_Build_In_Place_Result_Type
(Typ
)
315 and then not No_Ctrl_Actions
(N
)
317 -- This function is called early, before name resolution is
318 -- complete, so we have to deal with things that might turn into
319 -- function calls later. N_Function_Call and N_Op nodes are the
320 -- obvious case. An N_Identifier or N_Expanded_Name is a
321 -- parameterless function call if it denotes a function.
322 -- Finally, an attribute reference can be a function call.
324 case Nkind
(Unqual_Conv
(Rhs
)) is
333 case Ekind
(Entity
(Unqual_Conv
(Rhs
))) is
343 when N_Attribute_Reference
=>
344 Result
:= Attribute_Name
(Unqual_Conv
(Rhs
)) = Name_Input
;
345 -- T'Input will turn into a call whose result type is T
355 end Should_Transform_BIP_Assignment
;
357 ------------------------------
358 -- Transform_BIP_Assignment --
359 ------------------------------
361 procedure Transform_BIP_Assignment
(Typ
: Entity_Id
) is
363 -- Tranform "X : [constant] T := F (...);" into:
365 -- Temp : constant T := F (...);
368 Loc
: constant Source_Ptr
:= Sloc
(N
);
369 Def_Id
: constant Entity_Id
:= Make_Temporary
(Loc
, 'Y', Rhs
);
370 Obj_Decl
: constant Node_Id
:=
371 Make_Object_Declaration
(Loc
,
372 Defining_Identifier
=> Def_Id
,
373 Constant_Present
=> True,
374 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
),
376 Has_Init_Expression
=> True);
379 Set_Etype
(Def_Id
, Typ
);
380 Set_Expression
(N
, New_Occurrence_Of
(Def_Id
, Loc
));
382 -- At this point, Rhs is no longer equal to Expression (N), so:
384 Rhs
:= Expression
(N
);
386 Insert_Action
(N
, Obj_Decl
);
387 end Transform_BIP_Assignment
;
394 Save_Full_Analysis
: Boolean := False;
395 -- Force initialization to facilitate static analysis
397 Saved_GM
: constant Ghost_Mode_Type
:= Ghost_Mode
;
398 -- Save the Ghost mode to restore on exit
400 -- Start of processing for Analyze_Assignment
403 Mark_Coextensions
(N
, Rhs
);
405 -- Preserve relevant elaboration-related attributes of the context which
406 -- are no longer available or very expensive to recompute once analysis,
407 -- resolution, and expansion are over.
409 Mark_Elaboration_Attributes
414 -- Analyze the target of the assignment first in case the expression
415 -- contains references to Ghost entities. The checks that verify the
416 -- proper use of a Ghost entity need to know the enclosing context.
420 -- An assignment statement is Ghost when the left hand side denotes a
421 -- Ghost entity. Set the mode now to ensure that any nodes generated
422 -- during analysis and expansion are properly marked as Ghost.
424 if Has_Target_Names
(N
) then
425 Current_Assignment
:= N
;
426 Expander_Mode_Save_And_Set
(False);
427 Save_Full_Analysis
:= Full_Analysis
;
428 Full_Analysis
:= False;
430 Current_Assignment
:= Empty
;
433 Mark_And_Set_Ghost_Assignment
(N
);
436 -- Ensure that we never do an assignment on a variable marked as
437 -- Is_Safe_To_Reevaluate.
440 (not Is_Entity_Name
(Lhs
)
441 or else Ekind
(Entity
(Lhs
)) /= E_Variable
442 or else not Is_Safe_To_Reevaluate
(Entity
(Lhs
)));
444 -- Start type analysis for assignment
448 -- In the most general case, both Lhs and Rhs can be overloaded, and we
449 -- must compute the intersection of the possible types on each side.
451 if Is_Overloaded
(Lhs
) then
458 Get_First_Interp
(Lhs
, I
, It
);
460 while Present
(It
.Typ
) loop
462 -- An indexed component with generalized indexing is always
463 -- overloaded with the corresponding dereference. Discard the
464 -- interpretation that yields a reference type, which is not
467 if Nkind
(Lhs
) = N_Indexed_Component
468 and then Present
(Generalized_Indexing
(Lhs
))
469 and then Has_Implicit_Dereference
(It
.Typ
)
473 -- This may be a call to a parameterless function through an
474 -- implicit dereference, so discard interpretation as well.
476 elsif Is_Entity_Name
(Lhs
)
477 and then Has_Implicit_Dereference
(It
.Typ
)
481 elsif Has_Compatible_Type
(Rhs
, It
.Typ
) then
482 if T1
= Any_Type
then
485 -- An explicit dereference is overloaded if the prefix
486 -- is. Try to remove the ambiguity on the prefix, the
487 -- error will be posted there if the ambiguity is real.
489 if Nkind
(Lhs
) = N_Explicit_Dereference
then
492 PI1
: Interp_Index
:= 0;
498 Get_First_Interp
(Prefix
(Lhs
), PI
, PIt
);
500 while Present
(PIt
.Typ
) loop
501 if Is_Access_Type
(PIt
.Typ
)
502 and then Has_Compatible_Type
503 (Rhs
, Designated_Type
(PIt
.Typ
))
507 Disambiguate
(Prefix
(Lhs
),
510 if PIt
= No_Interp
then
512 ("ambiguous left-hand side in "
513 & "assignment", Lhs
);
516 Resolve
(Prefix
(Lhs
), PIt
.Typ
);
526 Get_Next_Interp
(PI
, PIt
);
532 ("ambiguous left-hand side in assignment", Lhs
);
538 Get_Next_Interp
(I
, It
);
542 if T1
= Any_Type
then
544 ("no valid types for left-hand side for assignment", Lhs
);
550 -- Deal with build-in-place calls for nonlimited types. We don't do this
551 -- later, because resolving the rhs tranforms it incorrectly for build-
554 if Should_Transform_BIP_Assignment
(Typ
=> T1
) then
555 -- In certain cases involving user-defined concatenation operators,
556 -- we need to resolve the right-hand side before transforming the
559 case Nkind
(Unqual_Conv
(Rhs
)) is
560 when N_Function_Call
=>
563 First
(Parameter_Associations
(Unqual_Conv
(Rhs
)));
564 Actual_Exp
: Node_Id
;
567 while Present
(Actual
) loop
568 if Nkind
(Actual
) = N_Parameter_Association
then
569 Actual_Exp
:= Explicit_Actual_Parameter
(Actual
);
571 Actual_Exp
:= Actual
;
574 if Nkind
(Actual_Exp
) = N_Op_Concat
then
586 | N_Attribute_Reference
594 Transform_BIP_Assignment
(Typ
=> T1
);
597 pragma Assert
(not Should_Transform_BIP_Assignment
(Typ
=> T1
));
599 -- The resulting assignment type is T1, so now we will resolve the left
600 -- hand side of the assignment using this determined type.
604 -- Cases where Lhs is not a variable. In an instance or an inlined body
605 -- no need for further check because assignment was legal in template.
607 if In_Inlined_Body
then
610 elsif not Is_Variable
(Lhs
) then
612 -- Ada 2005 (AI-327): Check assignment to the attribute Priority of a
620 if Ada_Version
>= Ada_2005
then
622 -- Handle chains of renamings
625 while Nkind
(Ent
) in N_Has_Entity
626 and then Present
(Entity
(Ent
))
627 and then Present
(Renamed_Object
(Entity
(Ent
)))
629 Ent
:= Renamed_Object
(Entity
(Ent
));
632 if (Nkind
(Ent
) = N_Attribute_Reference
633 and then Attribute_Name
(Ent
) = Name_Priority
)
635 -- Renamings of the attribute Priority applied to protected
636 -- objects have been previously expanded into calls to the
637 -- Get_Ceiling run-time subprogram.
639 or else Is_Expanded_Priority_Attribute
(Ent
)
641 -- The enclosing subprogram cannot be a protected function
644 while not (Is_Subprogram
(S
)
645 and then Convention
(S
) = Convention_Protected
)
646 and then S
/= Standard_Standard
651 if Ekind
(S
) = E_Function
652 and then Convention
(S
) = Convention_Protected
655 ("protected function cannot modify protected object",
659 -- Changes of the ceiling priority of the protected object
660 -- are only effective if the Ceiling_Locking policy is in
661 -- effect (AARM D.5.2 (5/2)).
663 if Locking_Policy
/= 'C' then
665 ("assignment to the attribute PRIORITY has no effect??",
668 ("\since no Locking_Policy has been specified??", Lhs
);
676 Diagnose_Non_Variable_Lhs
(Lhs
);
679 -- Error of assigning to limited type. We do however allow this in
680 -- certain cases where the front end generates the assignments.
682 elsif Is_Limited_Type
(T1
)
683 and then not Assignment_OK
(Lhs
)
684 and then not Assignment_OK
(Original_Node
(Lhs
))
686 -- CPP constructors can only be called in declarations
688 if Is_CPP_Constructor_Call
(Rhs
) then
689 Error_Msg_N
("invalid use of 'C'P'P constructor", Rhs
);
692 ("left hand of assignment must not be limited type", Lhs
);
693 Explain_Limited_Type
(T1
, Lhs
);
698 -- A class-wide type may be a limited view. This illegal case is not
699 -- caught by previous checks.
701 elsif Ekind
(T1
) = E_Class_Wide_Type
and then From_Limited_With
(T1
) then
702 Error_Msg_NE
("invalid use of limited view of&", Lhs
, T1
);
705 -- Enforce RM 3.9.3 (8): the target of an assignment operation cannot be
706 -- abstract. This is only checked when the assignment Comes_From_Source,
707 -- because in some cases the expander generates such assignments (such
708 -- in the _assign operation for an abstract type).
710 elsif Is_Abstract_Type
(T1
) and then Comes_From_Source
(N
) then
712 ("target of assignment operation must not be abstract", Lhs
);
715 -- Resolution may have updated the subtype, in case the left-hand side
716 -- is a private protected component. Use the correct subtype to avoid
717 -- scoping issues in the back-end.
721 -- Ada 2005 (AI-50217, AI-326): Check wrong dereference of incomplete
722 -- type. For example:
726 -- type Acc is access P.T;
729 -- with Pkg; use Acc;
730 -- procedure Example is
733 -- A.all := B.all; -- ERROR
736 if Nkind
(Lhs
) = N_Explicit_Dereference
737 and then Ekind
(T1
) = E_Incomplete_Type
739 Error_Msg_N
("invalid use of incomplete type", Lhs
);
744 -- Now we can complete the resolution of the right hand side
746 Set_Assignment_Type
(Lhs
, T1
);
748 -- If the target of the assignment is an entity of a mutable type and
749 -- the expression is a conditional expression, its alternatives can be
750 -- of different subtypes of the nominal type of the LHS, so they must be
751 -- resolved with the base type, given that their subtype may differ from
752 -- that of the target mutable object.
754 if Is_Entity_Name
(Lhs
)
755 and then Ekind_In
(Entity
(Lhs
), E_In_Out_Parameter
,
758 and then Is_Composite_Type
(T1
)
759 and then not Is_Constrained
(Etype
(Entity
(Lhs
)))
760 and then Nkind_In
(Rhs
, N_If_Expression
, N_Case_Expression
)
762 Resolve
(Rhs
, Base_Type
(T1
));
768 -- This is the point at which we check for an unset reference
770 Check_Unset_Reference
(Rhs
);
771 Check_Unprotected_Access
(Lhs
, Rhs
);
773 -- Remaining steps are skipped if Rhs was syntactically in error
782 if not Covers
(T1
, T2
) then
783 Wrong_Type
(Rhs
, Etype
(Lhs
));
788 -- Ada 2005 (AI-326): In case of explicit dereference of incomplete
789 -- types, use the non-limited view if available
791 if Nkind
(Rhs
) = N_Explicit_Dereference
792 and then Is_Tagged_Type
(T2
)
793 and then Has_Non_Limited_View
(T2
)
795 T2
:= Non_Limited_View
(T2
);
798 Set_Assignment_Type
(Rhs
, T2
);
800 if Total_Errors_Detected
/= 0 then
810 if T1
= Any_Type
or else T2
= Any_Type
then
815 -- If the rhs is class-wide or dynamically tagged, then require the lhs
816 -- to be class-wide. The case where the rhs is a dynamically tagged call
817 -- to a dispatching operation with a controlling access result is
818 -- excluded from this check, since the target has an access type (and
819 -- no tag propagation occurs in that case).
821 if (Is_Class_Wide_Type
(T2
)
822 or else (Is_Dynamically_Tagged
(Rhs
)
823 and then not Is_Access_Type
(T1
)))
824 and then not Is_Class_Wide_Type
(T1
)
826 Error_Msg_N
("dynamically tagged expression not allowed!", Rhs
);
828 elsif Is_Class_Wide_Type
(T1
)
829 and then not Is_Class_Wide_Type
(T2
)
830 and then not Is_Tag_Indeterminate
(Rhs
)
831 and then not Is_Dynamically_Tagged
(Rhs
)
833 Error_Msg_N
("dynamically tagged expression required!", Rhs
);
836 -- Propagate the tag from a class-wide target to the rhs when the rhs
837 -- is a tag-indeterminate call.
839 if Is_Tag_Indeterminate
(Rhs
) then
840 if Is_Class_Wide_Type
(T1
) then
841 Propagate_Tag
(Lhs
, Rhs
);
843 elsif Nkind
(Rhs
) = N_Function_Call
844 and then Is_Entity_Name
(Name
(Rhs
))
845 and then Is_Abstract_Subprogram
(Entity
(Name
(Rhs
)))
848 ("call to abstract function must be dispatching", Name
(Rhs
));
850 elsif Nkind
(Rhs
) = N_Qualified_Expression
851 and then Nkind
(Expression
(Rhs
)) = N_Function_Call
852 and then Is_Entity_Name
(Name
(Expression
(Rhs
)))
854 Is_Abstract_Subprogram
(Entity
(Name
(Expression
(Rhs
))))
857 ("call to abstract function must be dispatching",
858 Name
(Expression
(Rhs
)));
862 -- Ada 2005 (AI-385): When the lhs type is an anonymous access type,
863 -- apply an implicit conversion of the rhs to that type to force
864 -- appropriate static and run-time accessibility checks. This applies
865 -- as well to anonymous access-to-subprogram types that are component
866 -- subtypes or formal parameters.
868 if Ada_Version
>= Ada_2005
and then Is_Access_Type
(T1
) then
869 if Is_Local_Anonymous_Access
(T1
)
870 or else Ekind
(T2
) = E_Anonymous_Access_Subprogram_Type
872 -- Handle assignment to an Ada 2012 stand-alone object
873 -- of an anonymous access type.
875 or else (Ekind
(T1
) = E_Anonymous_Access_Type
876 and then Nkind
(Associated_Node_For_Itype
(T1
)) =
877 N_Object_Declaration
)
880 Rewrite
(Rhs
, Convert_To
(T1
, Relocate_Node
(Rhs
)));
881 Analyze_And_Resolve
(Rhs
, T1
);
885 -- Ada 2005 (AI-231): Assignment to not null variable
887 if Ada_Version
>= Ada_2005
888 and then Can_Never_Be_Null
(T1
)
889 and then not Assignment_OK
(Lhs
)
891 -- Case where we know the right hand side is null
893 if Known_Null
(Rhs
) then
894 Apply_Compile_Time_Constraint_Error
897 "(Ada 2005) null not allowed in null-excluding objects??",
898 Reason
=> CE_Null_Not_Allowed
);
900 -- We still mark this as a possible modification, that's necessary
901 -- to reset Is_True_Constant, and desirable for xref purposes.
903 Note_Possible_Modification
(Lhs
, Sure
=> True);
906 -- If we know the right hand side is non-null, then we convert to the
907 -- target type, since we don't need a run time check in that case.
909 elsif not Can_Never_Be_Null
(T2
) then
910 Rewrite
(Rhs
, Convert_To
(T1
, Relocate_Node
(Rhs
)));
911 Analyze_And_Resolve
(Rhs
, T1
);
915 if Is_Scalar_Type
(T1
) then
916 Apply_Scalar_Range_Check
(Rhs
, Etype
(Lhs
));
918 -- For array types, verify that lengths match. If the right hand side
919 -- is a function call that has been inlined, the assignment has been
920 -- rewritten as a block, and the constraint check will be applied to the
921 -- assignment within the block.
923 elsif Is_Array_Type
(T1
)
924 and then (Nkind
(Rhs
) /= N_Type_Conversion
925 or else Is_Constrained
(Etype
(Rhs
)))
926 and then (Nkind
(Rhs
) /= N_Function_Call
927 or else Nkind
(N
) /= N_Block_Statement
)
929 -- Assignment verifies that the length of the Lsh and Rhs are equal,
930 -- but of course the indexes do not have to match. If the right-hand
931 -- side is a type conversion to an unconstrained type, a length check
932 -- is performed on the expression itself during expansion. In rare
933 -- cases, the redundant length check is computed on an index type
934 -- with a different representation, triggering incorrect code in the
937 Apply_Length_Check
(Rhs
, Etype
(Lhs
));
940 -- Discriminant checks are applied in the course of expansion
945 -- Note: modifications of the Lhs may only be recorded after
946 -- checks have been applied.
948 Note_Possible_Modification
(Lhs
, Sure
=> True);
950 -- ??? a real accessibility check is needed when ???
952 -- Post warning for redundant assignment or variable to itself
954 if Warn_On_Redundant_Constructs
956 -- We only warn for source constructs
958 and then Comes_From_Source
(N
)
960 -- Where the object is the same on both sides
962 and then Same_Object
(Lhs
, Original_Node
(Rhs
))
964 -- But exclude the case where the right side was an operation that
965 -- got rewritten (e.g. JUNK + K, where K was known to be zero). We
966 -- don't want to warn in such a case, since it is reasonable to write
967 -- such expressions especially when K is defined symbolically in some
970 and then Nkind
(Original_Node
(Rhs
)) not in N_Op
972 if Nkind
(Lhs
) in N_Has_Entity
then
973 Error_Msg_NE
-- CODEFIX
974 ("?r?useless assignment of & to itself!", N
, Entity
(Lhs
));
976 Error_Msg_N
-- CODEFIX
977 ("?r?useless assignment of object to itself!", N
);
981 -- Check for non-allowed composite assignment
983 if not Support_Composite_Assign_On_Target
984 and then (Is_Array_Type
(T1
) or else Is_Record_Type
(T1
))
985 and then (not Has_Size_Clause
(T1
) or else Esize
(T1
) > 64)
987 Error_Msg_CRT
("composite assignment", N
);
990 -- Save the scenario for later examination by the ABE Processing phase
992 Record_Elaboration_Scenario
(N
);
994 -- Set Referenced_As_LHS if appropriate. We only set this flag if the
995 -- assignment is a source assignment in the extended main source unit.
996 -- We are not interested in any reference information outside this
997 -- context, or in compiler generated assignment statements.
999 if Comes_From_Source
(N
)
1000 and then In_Extended_Main_Source_Unit
(Lhs
)
1002 Set_Referenced_Modified
(Lhs
, Out_Param
=> False);
1005 -- RM 7.3.2 (12/3): An assignment to a view conversion (from a type to
1006 -- one of its ancestors) requires an invariant check. Apply check only
1007 -- if expression comes from source, otherwise it will be applied when
1008 -- value is assigned to source entity. This is not done in GNATprove
1009 -- mode, as GNATprove handles invariant checks itself.
1011 if Nkind
(Lhs
) = N_Type_Conversion
1012 and then Has_Invariants
(Etype
(Expression
(Lhs
)))
1013 and then Comes_From_Source
(Expression
(Lhs
))
1014 and then not GNATprove_Mode
1016 Insert_After
(N
, Make_Invariant_Call
(Expression
(Lhs
)));
1019 -- Final step. If left side is an entity, then we may be able to reset
1020 -- the current tracked values to new safe values. We only have something
1021 -- to do if the left side is an entity name, and expansion has not
1022 -- modified the node into something other than an assignment, and of
1023 -- course we only capture values if it is safe to do so.
1025 if Is_Entity_Name
(Lhs
)
1026 and then Nkind
(N
) = N_Assignment_Statement
1029 Ent
: constant Entity_Id
:= Entity
(Lhs
);
1032 if Safe_To_Capture_Value
(N
, Ent
) then
1034 -- If simple variable on left side, warn if this assignment
1035 -- blots out another one (rendering it useless). We only do
1036 -- this for source assignments, otherwise we can generate bogus
1037 -- warnings when an assignment is rewritten as another
1038 -- assignment, and gets tied up with itself.
1040 -- There may have been a previous reference to a component of
1041 -- the variable, which in general removes the Last_Assignment
1042 -- field of the variable to indicate a relevant use of the
1043 -- previous assignment. However, if the assignment is to a
1044 -- subcomponent the reference may not have registered, because
1045 -- it is not possible to determine whether the context is an
1046 -- assignment. In those cases we generate a Deferred_Reference,
1047 -- to be used at the end of compilation to generate the right
1048 -- kind of reference, and we suppress a potential warning for
1049 -- a useless assignment, which might be premature. This may
1050 -- lose a warning in rare cases, but seems preferable to a
1051 -- misleading warning.
1053 if Warn_On_Modified_Unread
1054 and then Is_Assignable
(Ent
)
1055 and then Comes_From_Source
(N
)
1056 and then In_Extended_Main_Source_Unit
(Ent
)
1057 and then not Has_Deferred_Reference
(Ent
)
1059 Warn_On_Useless_Assignment
(Ent
, N
);
1062 -- If we are assigning an access type and the left side is an
1063 -- entity, then make sure that the Is_Known_[Non_]Null flags
1064 -- properly reflect the state of the entity after assignment.
1066 if Is_Access_Type
(T1
) then
1067 if Known_Non_Null
(Rhs
) then
1068 Set_Is_Known_Non_Null
(Ent
, True);
1070 elsif Known_Null
(Rhs
)
1071 and then not Can_Never_Be_Null
(Ent
)
1073 Set_Is_Known_Null
(Ent
, True);
1076 Set_Is_Known_Null
(Ent
, False);
1078 if not Can_Never_Be_Null
(Ent
) then
1079 Set_Is_Known_Non_Null
(Ent
, False);
1083 -- For discrete types, we may be able to set the current value
1084 -- if the value is known at compile time.
1086 elsif Is_Discrete_Type
(T1
)
1087 and then Compile_Time_Known_Value
(Rhs
)
1089 Set_Current_Value
(Ent
, Rhs
);
1091 Set_Current_Value
(Ent
, Empty
);
1094 -- If not safe to capture values, kill them
1102 -- If assigning to an object in whole or in part, note location of
1103 -- assignment in case no one references value. We only do this for
1104 -- source assignments, otherwise we can generate bogus warnings when an
1105 -- assignment is rewritten as another assignment, and gets tied up with
1109 Ent
: constant Entity_Id
:= Get_Enclosing_Object
(Lhs
);
1112 and then Safe_To_Capture_Value
(N
, Ent
)
1113 and then Nkind
(N
) = N_Assignment_Statement
1114 and then Warn_On_Modified_Unread
1115 and then Is_Assignable
(Ent
)
1116 and then Comes_From_Source
(N
)
1117 and then In_Extended_Main_Source_Unit
(Ent
)
1119 Set_Last_Assignment
(Ent
, Lhs
);
1123 Analyze_Dimension
(N
);
1126 Restore_Ghost_Mode
(Saved_GM
);
1128 -- If the right-hand side contains target names, expansion has been
1129 -- disabled to prevent expansion that might move target names out of
1130 -- the context of the assignment statement. Restore the expander mode
1131 -- now so that assignment statement can be properly expanded.
1133 if Nkind
(N
) = N_Assignment_Statement
then
1134 if Has_Target_Names
(N
) then
1135 Expander_Mode_Restore
;
1136 Full_Analysis
:= Save_Full_Analysis
;
1139 pragma Assert
(not Should_Transform_BIP_Assignment
(Typ
=> T1
));
1141 end Analyze_Assignment
;
1143 -----------------------------
1144 -- Analyze_Block_Statement --
1145 -----------------------------
1147 procedure Analyze_Block_Statement
(N
: Node_Id
) is
1148 procedure Install_Return_Entities
(Scop
: Entity_Id
);
1149 -- Install all entities of return statement scope Scop in the visibility
1150 -- chain except for the return object since its entity is reused in a
1153 -----------------------------
1154 -- Install_Return_Entities --
1155 -----------------------------
1157 procedure Install_Return_Entities
(Scop
: Entity_Id
) is
1161 Id
:= First_Entity
(Scop
);
1162 while Present
(Id
) loop
1164 -- Do not install the return object
1166 if not Ekind_In
(Id
, E_Constant
, E_Variable
)
1167 or else not Is_Return_Object
(Id
)
1169 Install_Entity
(Id
);
1174 end Install_Return_Entities
;
1176 -- Local constants and variables
1178 Decls
: constant List_Id
:= Declarations
(N
);
1179 Id
: constant Node_Id
:= Identifier
(N
);
1180 HSS
: constant Node_Id
:= Handled_Statement_Sequence
(N
);
1182 Is_BIP_Return_Statement
: Boolean;
1184 -- Start of processing for Analyze_Block_Statement
1187 -- In SPARK mode, we reject block statements. Note that the case of
1188 -- block statements generated by the expander is fine.
1190 if Nkind
(Original_Node
(N
)) = N_Block_Statement
then
1191 Check_SPARK_05_Restriction
("block statement is not allowed", N
);
1194 -- If no handled statement sequence is present, things are really messed
1195 -- up, and we just return immediately (defence against previous errors).
1198 Check_Error_Detected
;
1202 -- Detect whether the block is actually a rewritten return statement of
1203 -- a build-in-place function.
1205 Is_BIP_Return_Statement
:=
1207 and then Present
(Entity
(Id
))
1208 and then Ekind
(Entity
(Id
)) = E_Return_Statement
1209 and then Is_Build_In_Place_Function
1210 (Return_Applies_To
(Entity
(Id
)));
1212 -- Normal processing with HSS present
1215 EH
: constant List_Id
:= Exception_Handlers
(HSS
);
1216 Ent
: Entity_Id
:= Empty
;
1219 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
1220 -- Recursively save value of this global, will be restored on exit
1223 -- Initialize unblocked exit count for statements of begin block
1224 -- plus one for each exception handler that is present.
1226 Unblocked_Exit_Count
:= 1;
1228 if Present
(EH
) then
1229 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ List_Length
(EH
);
1232 -- If a label is present analyze it and mark it as referenced
1234 if Present
(Id
) then
1238 -- An error defense. If we have an identifier, but no entity, then
1239 -- something is wrong. If previous errors, then just remove the
1240 -- identifier and continue, otherwise raise an exception.
1243 Check_Error_Detected
;
1244 Set_Identifier
(N
, Empty
);
1247 Set_Ekind
(Ent
, E_Block
);
1248 Generate_Reference
(Ent
, N
, ' ');
1249 Generate_Definition
(Ent
);
1251 if Nkind
(Parent
(Ent
)) = N_Implicit_Label_Declaration
then
1252 Set_Label_Construct
(Parent
(Ent
), N
);
1257 -- If no entity set, create a label entity
1260 Ent
:= New_Internal_Entity
(E_Block
, Current_Scope
, Sloc
(N
), 'B');
1261 Set_Identifier
(N
, New_Occurrence_Of
(Ent
, Sloc
(N
)));
1262 Set_Parent
(Ent
, N
);
1265 Set_Etype
(Ent
, Standard_Void_Type
);
1266 Set_Block_Node
(Ent
, Identifier
(N
));
1269 -- The block served as an extended return statement. Ensure that any
1270 -- entities created during the analysis and expansion of the return
1271 -- object declaration are once again visible.
1273 if Is_BIP_Return_Statement
then
1274 Install_Return_Entities
(Ent
);
1277 if Present
(Decls
) then
1278 Analyze_Declarations
(Decls
);
1280 Inspect_Deferred_Constant_Completion
(Decls
);
1284 Process_End_Label
(HSS
, 'e', Ent
);
1286 -- If exception handlers are present, then we indicate that enclosing
1287 -- scopes contain a block with handlers. We only need to mark non-
1290 if Present
(EH
) then
1293 Set_Has_Nested_Block_With_Handler
(S
);
1294 exit when Is_Overloadable
(S
)
1295 or else Ekind
(S
) = E_Package
1296 or else Is_Generic_Unit
(S
);
1301 Check_References
(Ent
);
1302 Update_Use_Clause_Chain
;
1305 if Unblocked_Exit_Count
= 0 then
1306 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1307 Check_Unreachable_Code
(N
);
1309 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1312 end Analyze_Block_Statement
;
1314 --------------------------------
1315 -- Analyze_Compound_Statement --
1316 --------------------------------
1318 procedure Analyze_Compound_Statement
(N
: Node_Id
) is
1320 Analyze_List
(Actions
(N
));
1321 end Analyze_Compound_Statement
;
1323 ----------------------------
1324 -- Analyze_Case_Statement --
1325 ----------------------------
1327 procedure Analyze_Case_Statement
(N
: Node_Id
) is
1329 Exp_Type
: Entity_Id
;
1330 Exp_Btype
: Entity_Id
;
1333 Others_Present
: Boolean;
1334 -- Indicates if Others was present
1336 pragma Warnings
(Off
, Last_Choice
);
1337 -- Don't care about assigned value
1339 Statements_Analyzed
: Boolean := False;
1340 -- Set True if at least some statement sequences get analyzed. If False
1341 -- on exit, means we had a serious error that prevented full analysis of
1342 -- the case statement, and as a result it is not a good idea to output
1343 -- warning messages about unreachable code.
1345 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
1346 -- Recursively save value of this global, will be restored on exit
1348 procedure Non_Static_Choice_Error
(Choice
: Node_Id
);
1349 -- Error routine invoked by the generic instantiation below when the
1350 -- case statement has a non static choice.
1352 procedure Process_Statements
(Alternative
: Node_Id
);
1353 -- Analyzes the statements associated with a case alternative. Needed
1354 -- by instantiation below.
1356 package Analyze_Case_Choices
is new
1357 Generic_Analyze_Choices
1358 (Process_Associated_Node
=> Process_Statements
);
1359 use Analyze_Case_Choices
;
1360 -- Instantiation of the generic choice analysis package
1362 package Check_Case_Choices
is new
1363 Generic_Check_Choices
1364 (Process_Empty_Choice
=> No_OP
,
1365 Process_Non_Static_Choice
=> Non_Static_Choice_Error
,
1366 Process_Associated_Node
=> No_OP
);
1367 use Check_Case_Choices
;
1368 -- Instantiation of the generic choice processing package
1370 -----------------------------
1371 -- Non_Static_Choice_Error --
1372 -----------------------------
1374 procedure Non_Static_Choice_Error
(Choice
: Node_Id
) is
1376 Flag_Non_Static_Expr
1377 ("choice given in case statement is not static!", Choice
);
1378 end Non_Static_Choice_Error
;
1380 ------------------------
1381 -- Process_Statements --
1382 ------------------------
1384 procedure Process_Statements
(Alternative
: Node_Id
) is
1385 Choices
: constant List_Id
:= Discrete_Choices
(Alternative
);
1389 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
1390 Statements_Analyzed
:= True;
1392 -- An interesting optimization. If the case statement expression
1393 -- is a simple entity, then we can set the current value within an
1394 -- alternative if the alternative has one possible value.
1398 -- when 2 | 3 => beta
1399 -- when others => gamma
1401 -- Here we know that N is initially 1 within alpha, but for beta and
1402 -- gamma, we do not know anything more about the initial value.
1404 if Is_Entity_Name
(Exp
) then
1405 Ent
:= Entity
(Exp
);
1407 if Ekind_In
(Ent
, E_Variable
,
1411 if List_Length
(Choices
) = 1
1412 and then Nkind
(First
(Choices
)) in N_Subexpr
1413 and then Compile_Time_Known_Value
(First
(Choices
))
1415 Set_Current_Value
(Entity
(Exp
), First
(Choices
));
1418 Analyze_Statements
(Statements
(Alternative
));
1420 -- After analyzing the case, set the current value to empty
1421 -- since we won't know what it is for the next alternative
1422 -- (unless reset by this same circuit), or after the case.
1424 Set_Current_Value
(Entity
(Exp
), Empty
);
1429 -- Case where expression is not an entity name of a variable
1431 Analyze_Statements
(Statements
(Alternative
));
1432 end Process_Statements
;
1434 -- Start of processing for Analyze_Case_Statement
1437 Unblocked_Exit_Count
:= 0;
1438 Exp
:= Expression
(N
);
1441 -- The expression must be of any discrete type. In rare cases, the
1442 -- expander constructs a case statement whose expression has a private
1443 -- type whose full view is discrete. This can happen when generating
1444 -- a stream operation for a variant type after the type is frozen,
1445 -- when the partial of view of the type of the discriminant is private.
1446 -- In that case, use the full view to analyze case alternatives.
1448 if not Is_Overloaded
(Exp
)
1449 and then not Comes_From_Source
(N
)
1450 and then Is_Private_Type
(Etype
(Exp
))
1451 and then Present
(Full_View
(Etype
(Exp
)))
1452 and then Is_Discrete_Type
(Full_View
(Etype
(Exp
)))
1454 Resolve
(Exp
, Etype
(Exp
));
1455 Exp_Type
:= Full_View
(Etype
(Exp
));
1458 Analyze_And_Resolve
(Exp
, Any_Discrete
);
1459 Exp_Type
:= Etype
(Exp
);
1462 Check_Unset_Reference
(Exp
);
1463 Exp_Btype
:= Base_Type
(Exp_Type
);
1465 -- The expression must be of a discrete type which must be determinable
1466 -- independently of the context in which the expression occurs, but
1467 -- using the fact that the expression must be of a discrete type.
1468 -- Moreover, the type this expression must not be a character literal
1469 -- (which is always ambiguous) or, for Ada-83, a generic formal type.
1471 -- If error already reported by Resolve, nothing more to do
1473 if Exp_Btype
= Any_Discrete
or else Exp_Btype
= Any_Type
then
1476 elsif Exp_Btype
= Any_Character
then
1478 ("character literal as case expression is ambiguous", Exp
);
1481 elsif Ada_Version
= Ada_83
1482 and then (Is_Generic_Type
(Exp_Btype
)
1483 or else Is_Generic_Type
(Root_Type
(Exp_Btype
)))
1486 ("(Ada 83) case expression cannot be of a generic type", Exp
);
1490 -- If the case expression is a formal object of mode in out, then treat
1491 -- it as having a nonstatic subtype by forcing use of the base type
1492 -- (which has to get passed to Check_Case_Choices below). Also use base
1493 -- type when the case expression is parenthesized.
1495 if Paren_Count
(Exp
) > 0
1496 or else (Is_Entity_Name
(Exp
)
1497 and then Ekind
(Entity
(Exp
)) = E_Generic_In_Out_Parameter
)
1499 Exp_Type
:= Exp_Btype
;
1502 -- Call instantiated procedures to analyzwe and check discrete choices
1504 Analyze_Choices
(Alternatives
(N
), Exp_Type
);
1505 Check_Choices
(N
, Alternatives
(N
), Exp_Type
, Others_Present
);
1507 -- Case statement with single OTHERS alternative not allowed in SPARK
1509 if Others_Present
and then List_Length
(Alternatives
(N
)) = 1 then
1510 Check_SPARK_05_Restriction
1511 ("OTHERS as unique case alternative is not allowed", N
);
1514 if Exp_Type
= Universal_Integer
and then not Others_Present
then
1515 Error_Msg_N
("case on universal integer requires OTHERS choice", Exp
);
1518 -- If all our exits were blocked by unconditional transfers of control,
1519 -- then the entire CASE statement acts as an unconditional transfer of
1520 -- control, so treat it like one, and check unreachable code. Skip this
1521 -- test if we had serious errors preventing any statement analysis.
1523 if Unblocked_Exit_Count
= 0 and then Statements_Analyzed
then
1524 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1525 Check_Unreachable_Code
(N
);
1527 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1530 -- If the expander is active it will detect the case of a statically
1531 -- determined single alternative and remove warnings for the case, but
1532 -- if we are not doing expansion, that circuit won't be active. Here we
1533 -- duplicate the effect of removing warnings in the same way, so that
1534 -- we will get the same set of warnings in -gnatc mode.
1536 if not Expander_Active
1537 and then Compile_Time_Known_Value
(Expression
(N
))
1538 and then Serious_Errors_Detected
= 0
1541 Chosen
: constant Node_Id
:= Find_Static_Alternative
(N
);
1545 Alt
:= First
(Alternatives
(N
));
1546 while Present
(Alt
) loop
1547 if Alt
/= Chosen
then
1548 Remove_Warning_Messages
(Statements
(Alt
));
1555 end Analyze_Case_Statement
;
1557 ----------------------------
1558 -- Analyze_Exit_Statement --
1559 ----------------------------
1561 -- If the exit includes a name, it must be the name of a currently open
1562 -- loop. Otherwise there must be an innermost open loop on the stack, to
1563 -- which the statement implicitly refers.
1565 -- Additionally, in SPARK mode:
1567 -- The exit can only name the closest enclosing loop;
1569 -- An exit with a when clause must be directly contained in a loop;
1571 -- An exit without a when clause must be directly contained in an
1572 -- if-statement with no elsif or else, which is itself directly contained
1573 -- in a loop. The exit must be the last statement in the if-statement.
1575 procedure Analyze_Exit_Statement
(N
: Node_Id
) is
1576 Target
: constant Node_Id
:= Name
(N
);
1577 Cond
: constant Node_Id
:= Condition
(N
);
1578 Scope_Id
: Entity_Id
:= Empty
; -- initialize to prevent warning
1584 Check_Unreachable_Code
(N
);
1587 if Present
(Target
) then
1589 U_Name
:= Entity
(Target
);
1591 if not In_Open_Scopes
(U_Name
) or else Ekind
(U_Name
) /= E_Loop
then
1592 Error_Msg_N
("invalid loop name in exit statement", N
);
1596 if Has_Loop_In_Inner_Open_Scopes
(U_Name
) then
1597 Check_SPARK_05_Restriction
1598 ("exit label must name the closest enclosing loop", N
);
1601 Set_Has_Exit
(U_Name
);
1608 for J
in reverse 0 .. Scope_Stack
.Last
loop
1609 Scope_Id
:= Scope_Stack
.Table
(J
).Entity
;
1610 Kind
:= Ekind
(Scope_Id
);
1612 if Kind
= E_Loop
and then (No
(Target
) or else Scope_Id
= U_Name
) then
1613 Set_Has_Exit
(Scope_Id
);
1616 elsif Kind
= E_Block
1617 or else Kind
= E_Loop
1618 or else Kind
= E_Return_Statement
1624 ("cannot exit from program unit or accept statement", N
);
1629 -- Verify that if present the condition is a Boolean expression
1631 if Present
(Cond
) then
1632 Analyze_And_Resolve
(Cond
, Any_Boolean
);
1633 Check_Unset_Reference
(Cond
);
1636 -- In SPARK mode, verify that the exit statement respects the SPARK
1639 if Present
(Cond
) then
1640 if Nkind
(Parent
(N
)) /= N_Loop_Statement
then
1641 Check_SPARK_05_Restriction
1642 ("exit with when clause must be directly in loop", N
);
1646 if Nkind
(Parent
(N
)) /= N_If_Statement
then
1647 if Nkind
(Parent
(N
)) = N_Elsif_Part
then
1648 Check_SPARK_05_Restriction
1649 ("exit must be in IF without ELSIF", N
);
1651 Check_SPARK_05_Restriction
("exit must be directly in IF", N
);
1654 elsif Nkind
(Parent
(Parent
(N
))) /= N_Loop_Statement
then
1655 Check_SPARK_05_Restriction
1656 ("exit must be in IF directly in loop", N
);
1658 -- First test the presence of ELSE, so that an exit in an ELSE leads
1659 -- to an error mentioning the ELSE.
1661 elsif Present
(Else_Statements
(Parent
(N
))) then
1662 Check_SPARK_05_Restriction
("exit must be in IF without ELSE", N
);
1664 -- An exit in an ELSIF does not reach here, as it would have been
1665 -- detected in the case (Nkind (Parent (N)) /= N_If_Statement).
1667 elsif Present
(Elsif_Parts
(Parent
(N
))) then
1668 Check_SPARK_05_Restriction
("exit must be in IF without ELSIF", N
);
1672 -- Chain exit statement to associated loop entity
1674 Set_Next_Exit_Statement
(N
, First_Exit_Statement
(Scope_Id
));
1675 Set_First_Exit_Statement
(Scope_Id
, N
);
1677 -- Since the exit may take us out of a loop, any previous assignment
1678 -- statement is not useless, so clear last assignment indications. It
1679 -- is OK to keep other current values, since if the exit statement
1680 -- does not exit, then the current values are still valid.
1682 Kill_Current_Values
(Last_Assignment_Only
=> True);
1683 end Analyze_Exit_Statement
;
1685 ----------------------------
1686 -- Analyze_Goto_Statement --
1687 ----------------------------
1689 procedure Analyze_Goto_Statement
(N
: Node_Id
) is
1690 Label
: constant Node_Id
:= Name
(N
);
1691 Scope_Id
: Entity_Id
;
1692 Label_Scope
: Entity_Id
;
1693 Label_Ent
: Entity_Id
;
1696 Check_SPARK_05_Restriction
("goto statement is not allowed", N
);
1698 -- Actual semantic checks
1700 Check_Unreachable_Code
(N
);
1701 Kill_Current_Values
(Last_Assignment_Only
=> True);
1704 Label_Ent
:= Entity
(Label
);
1706 -- Ignore previous error
1708 if Label_Ent
= Any_Id
then
1709 Check_Error_Detected
;
1712 -- We just have a label as the target of a goto
1714 elsif Ekind
(Label_Ent
) /= E_Label
then
1715 Error_Msg_N
("target of goto statement must be a label", Label
);
1718 -- Check that the target of the goto is reachable according to Ada
1719 -- scoping rules. Note: the special gotos we generate for optimizing
1720 -- local handling of exceptions would violate these rules, but we mark
1721 -- such gotos as analyzed when built, so this code is never entered.
1723 elsif not Reachable
(Label_Ent
) then
1724 Error_Msg_N
("target of goto statement is not reachable", Label
);
1728 -- Here if goto passes initial validity checks
1730 Label_Scope
:= Enclosing_Scope
(Label_Ent
);
1732 for J
in reverse 0 .. Scope_Stack
.Last
loop
1733 Scope_Id
:= Scope_Stack
.Table
(J
).Entity
;
1735 if Label_Scope
= Scope_Id
1736 or else not Ekind_In
(Scope_Id
, E_Block
, E_Loop
, E_Return_Statement
)
1738 if Scope_Id
/= Label_Scope
then
1740 ("cannot exit from program unit or accept statement", N
);
1747 raise Program_Error
;
1748 end Analyze_Goto_Statement
;
1750 --------------------------
1751 -- Analyze_If_Statement --
1752 --------------------------
1754 -- A special complication arises in the analysis of if statements
1756 -- The expander has circuitry to completely delete code that it can tell
1757 -- will not be executed (as a result of compile time known conditions). In
1758 -- the analyzer, we ensure that code that will be deleted in this manner
1759 -- is analyzed but not expanded. This is obviously more efficient, but
1760 -- more significantly, difficulties arise if code is expanded and then
1761 -- eliminated (e.g. exception table entries disappear). Similarly, itypes
1762 -- generated in deleted code must be frozen from start, because the nodes
1763 -- on which they depend will not be available at the freeze point.
1765 procedure Analyze_If_Statement
(N
: Node_Id
) is
1768 Save_Unblocked_Exit_Count
: constant Nat
:= Unblocked_Exit_Count
;
1769 -- Recursively save value of this global, will be restored on exit
1771 Save_In_Deleted_Code
: Boolean;
1773 Del
: Boolean := False;
1774 -- This flag gets set True if a True condition has been found, which
1775 -- means that remaining ELSE/ELSIF parts are deleted.
1777 procedure Analyze_Cond_Then
(Cnode
: Node_Id
);
1778 -- This is applied to either the N_If_Statement node itself or to an
1779 -- N_Elsif_Part node. It deals with analyzing the condition and the THEN
1780 -- statements associated with it.
1782 -----------------------
1783 -- Analyze_Cond_Then --
1784 -----------------------
1786 procedure Analyze_Cond_Then
(Cnode
: Node_Id
) is
1787 Cond
: constant Node_Id
:= Condition
(Cnode
);
1788 Tstm
: constant List_Id
:= Then_Statements
(Cnode
);
1791 Unblocked_Exit_Count
:= Unblocked_Exit_Count
+ 1;
1792 Analyze_And_Resolve
(Cond
, Any_Boolean
);
1793 Check_Unset_Reference
(Cond
);
1794 Set_Current_Value_Condition
(Cnode
);
1796 -- If already deleting, then just analyze then statements
1799 Analyze_Statements
(Tstm
);
1801 -- Compile time known value, not deleting yet
1803 elsif Compile_Time_Known_Value
(Cond
) then
1804 Save_In_Deleted_Code
:= In_Deleted_Code
;
1806 -- If condition is True, then analyze the THEN statements and set
1807 -- no expansion for ELSE and ELSIF parts.
1809 if Is_True
(Expr_Value
(Cond
)) then
1810 Analyze_Statements
(Tstm
);
1812 Expander_Mode_Save_And_Set
(False);
1813 In_Deleted_Code
:= True;
1815 -- If condition is False, analyze THEN with expansion off
1817 else -- Is_False (Expr_Value (Cond))
1818 Expander_Mode_Save_And_Set
(False);
1819 In_Deleted_Code
:= True;
1820 Analyze_Statements
(Tstm
);
1821 Expander_Mode_Restore
;
1822 In_Deleted_Code
:= Save_In_Deleted_Code
;
1825 -- Not known at compile time, not deleting, normal analysis
1828 Analyze_Statements
(Tstm
);
1830 end Analyze_Cond_Then
;
1832 -- Start of processing for Analyze_If_Statement
1835 -- Initialize exit count for else statements. If there is no else part,
1836 -- this count will stay non-zero reflecting the fact that the uncovered
1837 -- else case is an unblocked exit.
1839 Unblocked_Exit_Count
:= 1;
1840 Analyze_Cond_Then
(N
);
1842 -- Now to analyze the elsif parts if any are present
1844 if Present
(Elsif_Parts
(N
)) then
1845 E
:= First
(Elsif_Parts
(N
));
1846 while Present
(E
) loop
1847 Analyze_Cond_Then
(E
);
1852 if Present
(Else_Statements
(N
)) then
1853 Analyze_Statements
(Else_Statements
(N
));
1856 -- If all our exits were blocked by unconditional transfers of control,
1857 -- then the entire IF statement acts as an unconditional transfer of
1858 -- control, so treat it like one, and check unreachable code.
1860 if Unblocked_Exit_Count
= 0 then
1861 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1862 Check_Unreachable_Code
(N
);
1864 Unblocked_Exit_Count
:= Save_Unblocked_Exit_Count
;
1868 Expander_Mode_Restore
;
1869 In_Deleted_Code
:= Save_In_Deleted_Code
;
1872 if not Expander_Active
1873 and then Compile_Time_Known_Value
(Condition
(N
))
1874 and then Serious_Errors_Detected
= 0
1876 if Is_True
(Expr_Value
(Condition
(N
))) then
1877 Remove_Warning_Messages
(Else_Statements
(N
));
1879 if Present
(Elsif_Parts
(N
)) then
1880 E
:= First
(Elsif_Parts
(N
));
1881 while Present
(E
) loop
1882 Remove_Warning_Messages
(Then_Statements
(E
));
1888 Remove_Warning_Messages
(Then_Statements
(N
));
1892 -- Warn on redundant if statement that has no effect
1894 -- Note, we could also check empty ELSIF parts ???
1896 if Warn_On_Redundant_Constructs
1898 -- If statement must be from source
1900 and then Comes_From_Source
(N
)
1902 -- Condition must not have obvious side effect
1904 and then Has_No_Obvious_Side_Effects
(Condition
(N
))
1906 -- No elsif parts of else part
1908 and then No
(Elsif_Parts
(N
))
1909 and then No
(Else_Statements
(N
))
1911 -- Then must be a single null statement
1913 and then List_Length
(Then_Statements
(N
)) = 1
1915 -- Go to original node, since we may have rewritten something as
1916 -- a null statement (e.g. a case we could figure the outcome of).
1919 T
: constant Node_Id
:= First
(Then_Statements
(N
));
1920 S
: constant Node_Id
:= Original_Node
(T
);
1923 if Comes_From_Source
(S
) and then Nkind
(S
) = N_Null_Statement
then
1924 Error_Msg_N
("if statement has no effect?r?", N
);
1928 end Analyze_If_Statement
;
1930 ----------------------------------------
1931 -- Analyze_Implicit_Label_Declaration --
1932 ----------------------------------------
1934 -- An implicit label declaration is generated in the innermost enclosing
1935 -- declarative part. This is done for labels, and block and loop names.
1937 -- Note: any changes in this routine may need to be reflected in
1938 -- Analyze_Label_Entity.
1940 procedure Analyze_Implicit_Label_Declaration
(N
: Node_Id
) is
1941 Id
: constant Node_Id
:= Defining_Identifier
(N
);
1944 Set_Ekind
(Id
, E_Label
);
1945 Set_Etype
(Id
, Standard_Void_Type
);
1946 Set_Enclosing_Scope
(Id
, Current_Scope
);
1947 end Analyze_Implicit_Label_Declaration
;
1949 ------------------------------
1950 -- Analyze_Iteration_Scheme --
1951 ------------------------------
1953 procedure Analyze_Iteration_Scheme
(N
: Node_Id
) is
1955 Iter_Spec
: Node_Id
;
1956 Loop_Spec
: Node_Id
;
1959 -- For an infinite loop, there is no iteration scheme
1965 Cond
:= Condition
(N
);
1966 Iter_Spec
:= Iterator_Specification
(N
);
1967 Loop_Spec
:= Loop_Parameter_Specification
(N
);
1969 if Present
(Cond
) then
1970 Analyze_And_Resolve
(Cond
, Any_Boolean
);
1971 Check_Unset_Reference
(Cond
);
1972 Set_Current_Value_Condition
(N
);
1974 elsif Present
(Iter_Spec
) then
1975 Analyze_Iterator_Specification
(Iter_Spec
);
1978 Analyze_Loop_Parameter_Specification
(Loop_Spec
);
1980 end Analyze_Iteration_Scheme
;
1982 ------------------------------------
1983 -- Analyze_Iterator_Specification --
1984 ------------------------------------
1986 procedure Analyze_Iterator_Specification
(N
: Node_Id
) is
1987 procedure Check_Reverse_Iteration
(Typ
: Entity_Id
);
1988 -- For an iteration over a container, if the loop carries the Reverse
1989 -- indicator, verify that the container type has an Iterate aspect that
1990 -- implements the reversible iterator interface.
1992 function Get_Cursor_Type
(Typ
: Entity_Id
) return Entity_Id
;
1993 -- For containers with Iterator and related aspects, the cursor is
1994 -- obtained by locating an entity with the proper name in the scope
1997 -----------------------------
1998 -- Check_Reverse_Iteration --
1999 -----------------------------
2001 procedure Check_Reverse_Iteration
(Typ
: Entity_Id
) is
2003 if Reverse_Present
(N
) then
2004 if Is_Array_Type
(Typ
)
2005 or else Is_Reversible_Iterator
(Typ
)
2007 (Present
(Find_Aspect
(Typ
, Aspect_Iterable
))
2010 (Get_Iterable_Type_Primitive
(Typ
, Name_Previous
)))
2015 ("container type does not support reverse iteration", N
, Typ
);
2018 end Check_Reverse_Iteration
;
2020 ---------------------
2021 -- Get_Cursor_Type --
2022 ---------------------
2024 function Get_Cursor_Type
(Typ
: Entity_Id
) return Entity_Id
is
2028 -- If iterator type is derived, the cursor is declared in the scope
2029 -- of the parent type.
2031 if Is_Derived_Type
(Typ
) then
2032 Ent
:= First_Entity
(Scope
(Etype
(Typ
)));
2034 Ent
:= First_Entity
(Scope
(Typ
));
2037 while Present
(Ent
) loop
2038 exit when Chars
(Ent
) = Name_Cursor
;
2046 -- The cursor is the target of generated assignments in the
2047 -- loop, and cannot have a limited type.
2049 if Is_Limited_Type
(Etype
(Ent
)) then
2050 Error_Msg_N
("cursor type cannot be limited", N
);
2054 end Get_Cursor_Type
;
2058 Def_Id
: constant Node_Id
:= Defining_Identifier
(N
);
2059 Iter_Name
: constant Node_Id
:= Name
(N
);
2060 Loc
: constant Source_Ptr
:= Sloc
(N
);
2061 Subt
: constant Node_Id
:= Subtype_Indication
(N
);
2063 Bas
: Entity_Id
:= Empty
; -- initialize to prevent warning
2066 -- Start of processing for Analyze_Iterator_Specification
2069 Enter_Name
(Def_Id
);
2071 -- AI12-0151 specifies that when the subtype indication is present, it
2072 -- must statically match the type of the array or container element.
2073 -- To simplify this check, we introduce a subtype declaration with the
2074 -- given subtype indication when it carries a constraint, and rewrite
2075 -- the original as a reference to the created subtype entity.
2077 if Present
(Subt
) then
2078 if Nkind
(Subt
) = N_Subtype_Indication
then
2080 S
: constant Entity_Id
:= Make_Temporary
(Sloc
(Subt
), 'S');
2081 Decl
: constant Node_Id
:=
2082 Make_Subtype_Declaration
(Loc
,
2083 Defining_Identifier
=> S
,
2084 Subtype_Indication
=> New_Copy_Tree
(Subt
));
2086 Insert_Before
(Parent
(Parent
(N
)), Decl
);
2088 Rewrite
(Subt
, New_Occurrence_Of
(S
, Sloc
(Subt
)));
2094 -- Save entity of subtype indication for subsequent check
2096 Bas
:= Entity
(Subt
);
2099 Preanalyze_Range
(Iter_Name
);
2101 -- Set the kind of the loop variable, which is not visible within the
2104 Set_Ekind
(Def_Id
, E_Variable
);
2106 -- Provide a link between the iterator variable and the container, for
2107 -- subsequent use in cross-reference and modification information.
2109 if Of_Present
(N
) then
2110 Set_Related_Expression
(Def_Id
, Iter_Name
);
2112 -- For a container, the iterator is specified through the aspect
2114 if not Is_Array_Type
(Etype
(Iter_Name
)) then
2116 Iterator
: constant Entity_Id
:=
2117 Find_Value_Of_Aspect
2118 (Etype
(Iter_Name
), Aspect_Default_Iterator
);
2124 if No
(Iterator
) then
2125 null; -- error reported below
2127 elsif not Is_Overloaded
(Iterator
) then
2128 Check_Reverse_Iteration
(Etype
(Iterator
));
2130 -- If Iterator is overloaded, use reversible iterator if one is
2133 elsif Is_Overloaded
(Iterator
) then
2134 Get_First_Interp
(Iterator
, I
, It
);
2135 while Present
(It
.Nam
) loop
2136 if Ekind
(It
.Nam
) = E_Function
2137 and then Is_Reversible_Iterator
(Etype
(It
.Nam
))
2139 Set_Etype
(Iterator
, It
.Typ
);
2140 Set_Entity
(Iterator
, It
.Nam
);
2144 Get_Next_Interp
(I
, It
);
2147 Check_Reverse_Iteration
(Etype
(Iterator
));
2153 -- If the domain of iteration is an expression, create a declaration for
2154 -- it, so that finalization actions are introduced outside of the loop.
2155 -- The declaration must be a renaming because the body of the loop may
2156 -- assign to elements.
2158 if not Is_Entity_Name
(Iter_Name
)
2160 -- When the context is a quantified expression, the renaming
2161 -- declaration is delayed until the expansion phase if we are
2164 and then (Nkind
(Parent
(N
)) /= N_Quantified_Expression
2165 or else Operating_Mode
= Check_Semantics
)
2167 -- Do not perform this expansion for ASIS and when expansion is
2168 -- disabled, where the temporary may hide the transformation of a
2169 -- selected component into a prefixed function call, and references
2170 -- need to see the original expression.
2172 and then Expander_Active
2175 Id
: constant Entity_Id
:= Make_Temporary
(Loc
, 'R', Iter_Name
);
2181 -- If the domain of iteration is an array component that depends
2182 -- on a discriminant, create actual subtype for it. Pre-analysis
2183 -- does not generate the actual subtype of a selected component.
2185 if Nkind
(Iter_Name
) = N_Selected_Component
2186 and then Is_Array_Type
(Etype
(Iter_Name
))
2189 Build_Actual_Subtype_Of_Component
2190 (Etype
(Selector_Name
(Iter_Name
)), Iter_Name
);
2191 Insert_Action
(N
, Act_S
);
2193 if Present
(Act_S
) then
2194 Typ
:= Defining_Identifier
(Act_S
);
2196 Typ
:= Etype
(Iter_Name
);
2200 Typ
:= Etype
(Iter_Name
);
2202 -- Verify that the expression produces an iterator
2204 if not Of_Present
(N
) and then not Is_Iterator
(Typ
)
2205 and then not Is_Array_Type
(Typ
)
2206 and then No
(Find_Aspect
(Typ
, Aspect_Iterable
))
2209 ("expect object that implements iterator interface",
2214 -- Protect against malformed iterator
2216 if Typ
= Any_Type
then
2217 Error_Msg_N
("invalid expression in loop iterator", Iter_Name
);
2221 if not Of_Present
(N
) then
2222 Check_Reverse_Iteration
(Typ
);
2225 -- The name in the renaming declaration may be a function call.
2226 -- Indicate that it does not come from source, to suppress
2227 -- spurious warnings on renamings of parameterless functions,
2228 -- a common enough idiom in user-defined iterators.
2231 Make_Object_Renaming_Declaration
(Loc
,
2232 Defining_Identifier
=> Id
,
2233 Subtype_Mark
=> New_Occurrence_Of
(Typ
, Loc
),
2235 New_Copy_Tree
(Iter_Name
, New_Sloc
=> Loc
));
2237 Insert_Actions
(Parent
(Parent
(N
)), New_List
(Decl
));
2238 Rewrite
(Name
(N
), New_Occurrence_Of
(Id
, Loc
));
2239 Set_Etype
(Id
, Typ
);
2240 Set_Etype
(Name
(N
), Typ
);
2243 -- Container is an entity or an array with uncontrolled components, or
2244 -- else it is a container iterator given by a function call, typically
2245 -- called Iterate in the case of predefined containers, even though
2246 -- Iterate is not a reserved name. What matters is that the return type
2247 -- of the function is an iterator type.
2249 elsif Is_Entity_Name
(Iter_Name
) then
2250 Analyze
(Iter_Name
);
2252 if Nkind
(Iter_Name
) = N_Function_Call
then
2254 C
: constant Node_Id
:= Name
(Iter_Name
);
2259 if not Is_Overloaded
(Iter_Name
) then
2260 Resolve
(Iter_Name
, Etype
(C
));
2263 Get_First_Interp
(C
, I
, It
);
2264 while It
.Typ
/= Empty
loop
2265 if Reverse_Present
(N
) then
2266 if Is_Reversible_Iterator
(It
.Typ
) then
2267 Resolve
(Iter_Name
, It
.Typ
);
2271 elsif Is_Iterator
(It
.Typ
) then
2272 Resolve
(Iter_Name
, It
.Typ
);
2276 Get_Next_Interp
(I
, It
);
2281 -- Domain of iteration is not overloaded
2284 Resolve
(Iter_Name
, Etype
(Iter_Name
));
2287 if not Of_Present
(N
) then
2288 Check_Reverse_Iteration
(Etype
(Iter_Name
));
2292 -- Get base type of container, for proper retrieval of Cursor type
2293 -- and primitive operations.
2295 Typ
:= Base_Type
(Etype
(Iter_Name
));
2297 if Is_Array_Type
(Typ
) then
2298 if Of_Present
(N
) then
2299 Set_Etype
(Def_Id
, Component_Type
(Typ
));
2301 -- The loop variable is aliased if the array components are
2304 Set_Is_Aliased
(Def_Id
, Has_Aliased_Components
(Typ
));
2306 -- AI12-0047 stipulates that the domain (array or container)
2307 -- cannot be a component that depends on a discriminant if the
2308 -- enclosing object is mutable, to prevent a modification of the
2309 -- dowmain of iteration in the course of an iteration.
2311 -- If the object is an expression it has been captured in a
2312 -- temporary, so examine original node.
2314 if Nkind
(Original_Node
(Iter_Name
)) = N_Selected_Component
2315 and then Is_Dependent_Component_Of_Mutable_Object
2316 (Original_Node
(Iter_Name
))
2319 ("iterable name cannot be a discriminant-dependent "
2320 & "component of a mutable object", N
);
2325 (Base_Type
(Bas
) /= Base_Type
(Component_Type
(Typ
))
2327 not Subtypes_Statically_Match
(Bas
, Component_Type
(Typ
)))
2330 ("subtype indication does not match component type", Subt
);
2333 -- Here we have a missing Range attribute
2337 ("missing Range attribute in iteration over an array", N
);
2339 -- In Ada 2012 mode, this may be an attempt at an iterator
2341 if Ada_Version
>= Ada_2012
then
2343 ("\if& is meant to designate an element of the array, use OF",
2347 -- Prevent cascaded errors
2349 Set_Ekind
(Def_Id
, E_Loop_Parameter
);
2350 Set_Etype
(Def_Id
, Etype
(First_Index
(Typ
)));
2353 -- Check for type error in iterator
2355 elsif Typ
= Any_Type
then
2358 -- Iteration over a container
2361 Set_Ekind
(Def_Id
, E_Loop_Parameter
);
2362 Error_Msg_Ada_2012_Feature
("container iterator", Sloc
(N
));
2366 if Of_Present
(N
) then
2367 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2369 Elt
: constant Entity_Id
:=
2370 Get_Iterable_Type_Primitive
(Typ
, Name_Element
);
2374 ("missing Element primitive for iteration", N
);
2376 Set_Etype
(Def_Id
, Etype
(Elt
));
2377 Check_Reverse_Iteration
(Typ
);
2381 -- For a predefined container, The type of the loop variable is
2382 -- the Iterator_Element aspect of the container type.
2386 Element
: constant Entity_Id
:=
2387 Find_Value_Of_Aspect
2388 (Typ
, Aspect_Iterator_Element
);
2389 Iterator
: constant Entity_Id
:=
2390 Find_Value_Of_Aspect
2391 (Typ
, Aspect_Default_Iterator
);
2392 Orig_Iter_Name
: constant Node_Id
:=
2393 Original_Node
(Iter_Name
);
2394 Cursor_Type
: Entity_Id
;
2397 if No
(Element
) then
2398 Error_Msg_NE
("cannot iterate over&", N
, Typ
);
2402 Set_Etype
(Def_Id
, Entity
(Element
));
2403 Cursor_Type
:= Get_Cursor_Type
(Typ
);
2404 pragma Assert
(Present
(Cursor_Type
));
2406 -- If subtype indication was given, verify that it covers
2407 -- the element type of the container.
2410 and then (not Covers
(Bas
, Etype
(Def_Id
))
2411 or else not Subtypes_Statically_Match
2412 (Bas
, Etype
(Def_Id
)))
2415 ("subtype indication does not match element type",
2419 -- If the container has a variable indexing aspect, the
2420 -- element is a variable and is modifiable in the loop.
2422 if Has_Aspect
(Typ
, Aspect_Variable_Indexing
) then
2423 Set_Ekind
(Def_Id
, E_Variable
);
2426 -- If the container is a constant, iterating over it
2427 -- requires a Constant_Indexing operation.
2429 if not Is_Variable
(Iter_Name
)
2430 and then not Has_Aspect
(Typ
, Aspect_Constant_Indexing
)
2433 ("iteration over constant container require "
2434 & "constant_indexing aspect", N
);
2436 -- The Iterate function may have an in_out parameter,
2437 -- and a constant container is thus illegal.
2439 elsif Present
(Iterator
)
2440 and then Ekind
(Entity
(Iterator
)) = E_Function
2441 and then Ekind
(First_Formal
(Entity
(Iterator
))) /=
2443 and then not Is_Variable
(Iter_Name
)
2445 Error_Msg_N
("variable container expected", N
);
2448 -- Detect a case where the iterator denotes a component
2449 -- of a mutable object which depends on a discriminant.
2450 -- Note that the iterator may denote a function call in
2451 -- qualified form, in which case this check should not
2454 if Nkind
(Orig_Iter_Name
) = N_Selected_Component
2456 Present
(Entity
(Selector_Name
(Orig_Iter_Name
)))
2458 (Entity
(Selector_Name
(Orig_Iter_Name
)),
2461 and then Is_Dependent_Component_Of_Mutable_Object
2465 ("container cannot be a discriminant-dependent "
2466 & "component of a mutable object", N
);
2472 -- IN iterator, domain is a range, or a call to Iterate function
2475 -- For an iteration of the form IN, the name must denote an
2476 -- iterator, typically the result of a call to Iterate. Give a
2477 -- useful error message when the name is a container by itself.
2479 -- The type may be a formal container type, which has to have
2480 -- an Iterable aspect detailing the required primitives.
2482 if Is_Entity_Name
(Original_Node
(Name
(N
)))
2483 and then not Is_Iterator
(Typ
)
2485 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2488 elsif not Has_Aspect
(Typ
, Aspect_Iterator_Element
) then
2490 ("cannot iterate over&", Name
(N
), Typ
);
2493 ("name must be an iterator, not a container", Name
(N
));
2496 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2500 ("\to iterate directly over the elements of a container, "
2501 & "write `of &`", Name
(N
), Original_Node
(Name
(N
)));
2503 -- No point in continuing analysis of iterator spec
2509 -- If the name is a call (typically prefixed) to some Iterate
2510 -- function, it has been rewritten as an object declaration.
2511 -- If that object is a selected component, verify that it is not
2512 -- a component of an unconstrained mutable object.
2514 if Nkind
(Iter_Name
) = N_Identifier
2515 or else (not Expander_Active
and Comes_From_Source
(Iter_Name
))
2518 Orig_Node
: constant Node_Id
:= Original_Node
(Iter_Name
);
2519 Iter_Kind
: constant Node_Kind
:= Nkind
(Orig_Node
);
2523 if Iter_Kind
= N_Selected_Component
then
2524 Obj
:= Prefix
(Orig_Node
);
2526 elsif Iter_Kind
= N_Function_Call
then
2527 Obj
:= First_Actual
(Orig_Node
);
2529 -- If neither, the name comes from source
2535 if Nkind
(Obj
) = N_Selected_Component
2536 and then Is_Dependent_Component_Of_Mutable_Object
(Obj
)
2539 ("container cannot be a discriminant-dependent "
2540 & "component of a mutable object", N
);
2545 -- The result type of Iterate function is the classwide type of
2546 -- the interface parent. We need the specific Cursor type defined
2547 -- in the container package. We obtain it by name for a predefined
2548 -- container, or through the Iterable aspect for a formal one.
2550 if Has_Aspect
(Typ
, Aspect_Iterable
) then
2553 (Parent
(Find_Value_Of_Aspect
(Typ
, Aspect_Iterable
)),
2557 Set_Etype
(Def_Id
, Get_Cursor_Type
(Typ
));
2558 Check_Reverse_Iteration
(Etype
(Iter_Name
));
2563 end Analyze_Iterator_Specification
;
2569 -- Note: the semantic work required for analyzing labels (setting them as
2570 -- reachable) was done in a prepass through the statements in the block,
2571 -- so that forward gotos would be properly handled. See Analyze_Statements
2572 -- for further details. The only processing required here is to deal with
2573 -- optimizations that depend on an assumption of sequential control flow,
2574 -- since of course the occurrence of a label breaks this assumption.
2576 procedure Analyze_Label
(N
: Node_Id
) is
2577 pragma Warnings
(Off
, N
);
2579 Kill_Current_Values
;
2582 --------------------------
2583 -- Analyze_Label_Entity --
2584 --------------------------
2586 procedure Analyze_Label_Entity
(E
: Entity_Id
) is
2588 Set_Ekind
(E
, E_Label
);
2589 Set_Etype
(E
, Standard_Void_Type
);
2590 Set_Enclosing_Scope
(E
, Current_Scope
);
2591 Set_Reachable
(E
, True);
2592 end Analyze_Label_Entity
;
2594 ------------------------------------------
2595 -- Analyze_Loop_Parameter_Specification --
2596 ------------------------------------------
2598 procedure Analyze_Loop_Parameter_Specification
(N
: Node_Id
) is
2599 Loop_Nod
: constant Node_Id
:= Parent
(Parent
(N
));
2601 procedure Check_Controlled_Array_Attribute
(DS
: Node_Id
);
2602 -- If the bounds are given by a 'Range reference on a function call
2603 -- that returns a controlled array, introduce an explicit declaration
2604 -- to capture the bounds, so that the function result can be finalized
2605 -- in timely fashion.
2607 procedure Check_Predicate_Use
(T
: Entity_Id
);
2608 -- Diagnose Attempt to iterate through non-static predicate. Note that
2609 -- a type with inherited predicates may have both static and dynamic
2610 -- forms. In this case it is not sufficent to check the static predicate
2611 -- function only, look for a dynamic predicate aspect as well.
2613 function Has_Call_Using_Secondary_Stack
(N
: Node_Id
) return Boolean;
2614 -- N is the node for an arbitrary construct. This function searches the
2615 -- construct N to see if any expressions within it contain function
2616 -- calls that use the secondary stack, returning True if any such call
2617 -- is found, and False otherwise.
2619 procedure Process_Bounds
(R
: Node_Id
);
2620 -- If the iteration is given by a range, create temporaries and
2621 -- assignment statements block to capture the bounds and perform
2622 -- required finalization actions in case a bound includes a function
2623 -- call that uses the temporary stack. We first pre-analyze a copy of
2624 -- the range in order to determine the expected type, and analyze and
2625 -- resolve the original bounds.
2627 --------------------------------------
2628 -- Check_Controlled_Array_Attribute --
2629 --------------------------------------
2631 procedure Check_Controlled_Array_Attribute
(DS
: Node_Id
) is
2633 if Nkind
(DS
) = N_Attribute_Reference
2634 and then Is_Entity_Name
(Prefix
(DS
))
2635 and then Ekind
(Entity
(Prefix
(DS
))) = E_Function
2636 and then Is_Array_Type
(Etype
(Entity
(Prefix
(DS
))))
2638 Is_Controlled
(Component_Type
(Etype
(Entity
(Prefix
(DS
)))))
2639 and then Expander_Active
2642 Loc
: constant Source_Ptr
:= Sloc
(N
);
2643 Arr
: constant Entity_Id
:= Etype
(Entity
(Prefix
(DS
)));
2644 Indx
: constant Entity_Id
:=
2645 Base_Type
(Etype
(First_Index
(Arr
)));
2646 Subt
: constant Entity_Id
:= Make_Temporary
(Loc
, 'S');
2651 Make_Subtype_Declaration
(Loc
,
2652 Defining_Identifier
=> Subt
,
2653 Subtype_Indication
=>
2654 Make_Subtype_Indication
(Loc
,
2655 Subtype_Mark
=> New_Occurrence_Of
(Indx
, Loc
),
2657 Make_Range_Constraint
(Loc
, Relocate_Node
(DS
))));
2658 Insert_Before
(Loop_Nod
, Decl
);
2662 Make_Attribute_Reference
(Loc
,
2663 Prefix
=> New_Occurrence_Of
(Subt
, Loc
),
2664 Attribute_Name
=> Attribute_Name
(DS
)));
2669 end Check_Controlled_Array_Attribute
;
2671 -------------------------
2672 -- Check_Predicate_Use --
2673 -------------------------
2675 procedure Check_Predicate_Use
(T
: Entity_Id
) is
2677 -- A predicated subtype is illegal in loops and related constructs
2678 -- if the predicate is not static, or if it is a non-static subtype
2679 -- of a statically predicated subtype.
2681 if Is_Discrete_Type
(T
)
2682 and then Has_Predicates
(T
)
2683 and then (not Has_Static_Predicate
(T
)
2684 or else not Is_Static_Subtype
(T
)
2685 or else Has_Dynamic_Predicate_Aspect
(T
))
2687 -- Seems a confusing message for the case of a static predicate
2688 -- with a non-static subtype???
2690 Bad_Predicated_Subtype_Use
2691 ("cannot use subtype& with non-static predicate for loop "
2692 & "iteration", Discrete_Subtype_Definition
(N
),
2693 T
, Suggest_Static
=> True);
2695 elsif Inside_A_Generic
2696 and then Is_Generic_Formal
(T
)
2697 and then Is_Discrete_Type
(T
)
2699 Set_No_Dynamic_Predicate_On_Actual
(T
);
2701 end Check_Predicate_Use
;
2703 ------------------------------------
2704 -- Has_Call_Using_Secondary_Stack --
2705 ------------------------------------
2707 function Has_Call_Using_Secondary_Stack
(N
: Node_Id
) return Boolean is
2709 function Check_Call
(N
: Node_Id
) return Traverse_Result
;
2710 -- Check if N is a function call which uses the secondary stack
2716 function Check_Call
(N
: Node_Id
) return Traverse_Result
is
2719 Return_Typ
: Entity_Id
;
2722 if Nkind
(N
) = N_Function_Call
then
2725 -- Call using access to subprogram with explicit dereference
2727 if Nkind
(Nam
) = N_Explicit_Dereference
then
2728 Subp
:= Etype
(Nam
);
2730 -- Call using a selected component notation or Ada 2005 object
2731 -- operation notation
2733 elsif Nkind
(Nam
) = N_Selected_Component
then
2734 Subp
:= Entity
(Selector_Name
(Nam
));
2739 Subp
:= Entity
(Nam
);
2742 Return_Typ
:= Etype
(Subp
);
2744 if Is_Composite_Type
(Return_Typ
)
2745 and then not Is_Constrained
(Return_Typ
)
2749 elsif Sec_Stack_Needed_For_Return
(Subp
) then
2754 -- Continue traversing the tree
2759 function Check_Calls
is new Traverse_Func
(Check_Call
);
2761 -- Start of processing for Has_Call_Using_Secondary_Stack
2764 return Check_Calls
(N
) = Abandon
;
2765 end Has_Call_Using_Secondary_Stack
;
2767 --------------------
2768 -- Process_Bounds --
2769 --------------------
2771 procedure Process_Bounds
(R
: Node_Id
) is
2772 Loc
: constant Source_Ptr
:= Sloc
(N
);
2775 (Original_Bound
: Node_Id
;
2776 Analyzed_Bound
: Node_Id
;
2777 Typ
: Entity_Id
) return Node_Id
;
2778 -- Capture value of bound and return captured value
2785 (Original_Bound
: Node_Id
;
2786 Analyzed_Bound
: Node_Id
;
2787 Typ
: Entity_Id
) return Node_Id
2794 -- If the bound is a constant or an object, no need for a separate
2795 -- declaration. If the bound is the result of previous expansion
2796 -- it is already analyzed and should not be modified. Note that
2797 -- the Bound will be resolved later, if needed, as part of the
2798 -- call to Make_Index (literal bounds may need to be resolved to
2801 if Analyzed
(Original_Bound
) then
2802 return Original_Bound
;
2804 elsif Nkind_In
(Analyzed_Bound
, N_Integer_Literal
,
2805 N_Character_Literal
)
2806 or else Is_Entity_Name
(Analyzed_Bound
)
2808 Analyze_And_Resolve
(Original_Bound
, Typ
);
2809 return Original_Bound
;
2812 -- Normally, the best approach is simply to generate a constant
2813 -- declaration that captures the bound. However, there is a nasty
2814 -- case where this is wrong. If the bound is complex, and has a
2815 -- possible use of the secondary stack, we need to generate a
2816 -- separate assignment statement to ensure the creation of a block
2817 -- which will release the secondary stack.
2819 -- We prefer the constant declaration, since it leaves us with a
2820 -- proper trace of the value, useful in optimizations that get rid
2821 -- of junk range checks.
2823 if not Has_Call_Using_Secondary_Stack
(Analyzed_Bound
) then
2824 Analyze_And_Resolve
(Original_Bound
, Typ
);
2826 -- Ensure that the bound is valid. This check should not be
2827 -- generated when the range belongs to a quantified expression
2828 -- as the construct is still not expanded into its final form.
2830 if Nkind
(Parent
(R
)) /= N_Loop_Parameter_Specification
2831 or else Nkind
(Parent
(Parent
(R
))) /= N_Quantified_Expression
2833 Ensure_Valid
(Original_Bound
);
2836 Force_Evaluation
(Original_Bound
);
2837 return Original_Bound
;
2840 Id
:= Make_Temporary
(Loc
, 'R', Original_Bound
);
2842 -- Here we make a declaration with a separate assignment
2843 -- statement, and insert before loop header.
2846 Make_Object_Declaration
(Loc
,
2847 Defining_Identifier
=> Id
,
2848 Object_Definition
=> New_Occurrence_Of
(Typ
, Loc
));
2851 Make_Assignment_Statement
(Loc
,
2852 Name
=> New_Occurrence_Of
(Id
, Loc
),
2853 Expression
=> Relocate_Node
(Original_Bound
));
2855 Insert_Actions
(Loop_Nod
, New_List
(Decl
, Assign
));
2857 -- Now that this temporary variable is initialized we decorate it
2858 -- as safe-to-reevaluate to inform to the backend that no further
2859 -- asignment will be issued and hence it can be handled as side
2860 -- effect free. Note that this decoration must be done when the
2861 -- assignment has been analyzed because otherwise it will be
2862 -- rejected (see Analyze_Assignment).
2864 Set_Is_Safe_To_Reevaluate
(Id
);
2866 Rewrite
(Original_Bound
, New_Occurrence_Of
(Id
, Loc
));
2868 if Nkind
(Assign
) = N_Assignment_Statement
then
2869 return Expression
(Assign
);
2871 return Original_Bound
;
2875 Hi
: constant Node_Id
:= High_Bound
(R
);
2876 Lo
: constant Node_Id
:= Low_Bound
(R
);
2877 R_Copy
: constant Node_Id
:= New_Copy_Tree
(R
);
2882 -- Start of processing for Process_Bounds
2885 Set_Parent
(R_Copy
, Parent
(R
));
2886 Preanalyze_Range
(R_Copy
);
2887 Typ
:= Etype
(R_Copy
);
2889 -- If the type of the discrete range is Universal_Integer, then the
2890 -- bound's type must be resolved to Integer, and any object used to
2891 -- hold the bound must also have type Integer, unless the literal
2892 -- bounds are constant-folded expressions with a user-defined type.
2894 if Typ
= Universal_Integer
then
2895 if Nkind
(Lo
) = N_Integer_Literal
2896 and then Present
(Etype
(Lo
))
2897 and then Scope
(Etype
(Lo
)) /= Standard_Standard
2901 elsif Nkind
(Hi
) = N_Integer_Literal
2902 and then Present
(Etype
(Hi
))
2903 and then Scope
(Etype
(Hi
)) /= Standard_Standard
2908 Typ
:= Standard_Integer
;
2914 New_Lo
:= One_Bound
(Lo
, Low_Bound
(R_Copy
), Typ
);
2915 New_Hi
:= One_Bound
(Hi
, High_Bound
(R_Copy
), Typ
);
2917 -- Propagate staticness to loop range itself, in case the
2918 -- corresponding subtype is static.
2920 if New_Lo
/= Lo
and then Is_OK_Static_Expression
(New_Lo
) then
2921 Rewrite
(Low_Bound
(R
), New_Copy
(New_Lo
));
2924 if New_Hi
/= Hi
and then Is_OK_Static_Expression
(New_Hi
) then
2925 Rewrite
(High_Bound
(R
), New_Copy
(New_Hi
));
2931 DS
: constant Node_Id
:= Discrete_Subtype_Definition
(N
);
2932 Id
: constant Entity_Id
:= Defining_Identifier
(N
);
2936 -- Start of processing for Analyze_Loop_Parameter_Specification
2941 -- We always consider the loop variable to be referenced, since the loop
2942 -- may be used just for counting purposes.
2944 Generate_Reference
(Id
, N
, ' ');
2946 -- Check for the case of loop variable hiding a local variable (used
2947 -- later on to give a nice warning if the hidden variable is never
2951 H
: constant Entity_Id
:= Homonym
(Id
);
2954 and then Ekind
(H
) = E_Variable
2955 and then Is_Discrete_Type
(Etype
(H
))
2956 and then Enclosing_Dynamic_Scope
(H
) = Enclosing_Dynamic_Scope
(Id
)
2958 Set_Hiding_Loop_Variable
(H
, Id
);
2962 -- Loop parameter specification must include subtype mark in SPARK
2964 if Nkind
(DS
) = N_Range
then
2965 Check_SPARK_05_Restriction
2966 ("loop parameter specification must include subtype mark", N
);
2969 -- Analyze the subtype definition and create temporaries for the bounds.
2970 -- Do not evaluate the range when preanalyzing a quantified expression
2971 -- because bounds expressed as function calls with side effects will be
2972 -- incorrectly replicated.
2974 if Nkind
(DS
) = N_Range
2975 and then Expander_Active
2976 and then Nkind
(Parent
(N
)) /= N_Quantified_Expression
2978 Process_Bounds
(DS
);
2980 -- Either the expander not active or the range of iteration is a subtype
2981 -- indication, an entity, or a function call that yields an aggregate or
2985 DS_Copy
:= New_Copy_Tree
(DS
);
2986 Set_Parent
(DS_Copy
, Parent
(DS
));
2987 Preanalyze_Range
(DS_Copy
);
2989 -- Ada 2012: If the domain of iteration is:
2991 -- a) a function call,
2992 -- b) an identifier that is not a type,
2993 -- c) an attribute reference 'Old (within a postcondition),
2994 -- d) an unchecked conversion or a qualified expression with
2995 -- the proper iterator type.
2997 -- then it is an iteration over a container. It was classified as
2998 -- a loop specification by the parser, and must be rewritten now
2999 -- to activate container iteration. The last case will occur within
3000 -- an expanded inlined call, where the expansion wraps an actual in
3001 -- an unchecked conversion when needed. The expression of the
3002 -- conversion is always an object.
3004 if Nkind
(DS_Copy
) = N_Function_Call
3006 or else (Is_Entity_Name
(DS_Copy
)
3007 and then not Is_Type
(Entity
(DS_Copy
)))
3009 or else (Nkind
(DS_Copy
) = N_Attribute_Reference
3010 and then Nam_In
(Attribute_Name
(DS_Copy
),
3011 Name_Loop_Entry
, Name_Old
))
3013 or else Has_Aspect
(Etype
(DS_Copy
), Aspect_Iterable
)
3015 or else Nkind
(DS_Copy
) = N_Unchecked_Type_Conversion
3016 or else (Nkind
(DS_Copy
) = N_Qualified_Expression
3017 and then Is_Iterator
(Etype
(DS_Copy
)))
3019 -- This is an iterator specification. Rewrite it as such and
3020 -- analyze it to capture function calls that may require
3021 -- finalization actions.
3024 I_Spec
: constant Node_Id
:=
3025 Make_Iterator_Specification
(Sloc
(N
),
3026 Defining_Identifier
=> Relocate_Node
(Id
),
3028 Subtype_Indication
=> Empty
,
3029 Reverse_Present
=> Reverse_Present
(N
));
3030 Scheme
: constant Node_Id
:= Parent
(N
);
3033 Set_Iterator_Specification
(Scheme
, I_Spec
);
3034 Set_Loop_Parameter_Specification
(Scheme
, Empty
);
3035 Analyze_Iterator_Specification
(I_Spec
);
3037 -- In a generic context, analyze the original domain of
3038 -- iteration, for name capture.
3040 if not Expander_Active
then
3044 -- Set kind of loop parameter, which may be used in the
3045 -- subsequent analysis of the condition in a quantified
3048 Set_Ekind
(Id
, E_Loop_Parameter
);
3052 -- Domain of iteration is not a function call, and is side-effect
3056 -- A quantified expression that appears in a pre/post condition
3057 -- is pre-analyzed several times. If the range is given by an
3058 -- attribute reference it is rewritten as a range, and this is
3059 -- done even with expansion disabled. If the type is already set
3060 -- do not reanalyze, because a range with static bounds may be
3061 -- typed Integer by default.
3063 if Nkind
(Parent
(N
)) = N_Quantified_Expression
3064 and then Present
(Etype
(DS
))
3077 -- Some additional checks if we are iterating through a type
3079 if Is_Entity_Name
(DS
)
3080 and then Present
(Entity
(DS
))
3081 and then Is_Type
(Entity
(DS
))
3083 -- The subtype indication may denote the completion of an incomplete
3084 -- type declaration.
3086 if Ekind
(Entity
(DS
)) = E_Incomplete_Type
then
3087 Set_Entity
(DS
, Get_Full_View
(Entity
(DS
)));
3088 Set_Etype
(DS
, Entity
(DS
));
3091 Check_Predicate_Use
(Entity
(DS
));
3094 -- Error if not discrete type
3096 if not Is_Discrete_Type
(Etype
(DS
)) then
3097 Wrong_Type
(DS
, Any_Discrete
);
3098 Set_Etype
(DS
, Any_Type
);
3101 Check_Controlled_Array_Attribute
(DS
);
3103 if Nkind
(DS
) = N_Subtype_Indication
then
3104 Check_Predicate_Use
(Entity
(Subtype_Mark
(DS
)));
3107 Make_Index
(DS
, N
, In_Iter_Schm
=> True);
3108 Set_Ekind
(Id
, E_Loop_Parameter
);
3110 -- A quantified expression which appears in a pre- or post-condition may
3111 -- be analyzed multiple times. The analysis of the range creates several
3112 -- itypes which reside in different scopes depending on whether the pre-
3113 -- or post-condition has been expanded. Update the type of the loop
3114 -- variable to reflect the proper itype at each stage of analysis.
3117 or else Etype
(Id
) = Any_Type
3119 (Present
(Etype
(Id
))
3120 and then Is_Itype
(Etype
(Id
))
3121 and then Nkind
(Parent
(Loop_Nod
)) = N_Expression_With_Actions
3122 and then Nkind
(Original_Node
(Parent
(Loop_Nod
))) =
3123 N_Quantified_Expression
)
3125 Set_Etype
(Id
, Etype
(DS
));
3128 -- Treat a range as an implicit reference to the type, to inhibit
3129 -- spurious warnings.
3131 Generate_Reference
(Base_Type
(Etype
(DS
)), N
, ' ');
3132 Set_Is_Known_Valid
(Id
, True);
3134 -- The loop is not a declarative part, so the loop variable must be
3135 -- frozen explicitly. Do not freeze while preanalyzing a quantified
3136 -- expression because the freeze node will not be inserted into the
3137 -- tree due to flag Is_Spec_Expression being set.
3139 if Nkind
(Parent
(N
)) /= N_Quantified_Expression
then
3141 Flist
: constant List_Id
:= Freeze_Entity
(Id
, N
);
3143 if Is_Non_Empty_List
(Flist
) then
3144 Insert_Actions
(N
, Flist
);
3149 -- Case where we have a range or a subtype, get type bounds
3151 if Nkind_In
(DS
, N_Range
, N_Subtype_Indication
)
3152 and then not Error_Posted
(DS
)
3153 and then Etype
(DS
) /= Any_Type
3154 and then Is_Discrete_Type
(Etype
(DS
))
3161 if Nkind
(DS
) = N_Range
then
3162 L
:= Low_Bound
(DS
);
3163 H
:= High_Bound
(DS
);
3166 Type_Low_Bound
(Underlying_Type
(Etype
(Subtype_Mark
(DS
))));
3168 Type_High_Bound
(Underlying_Type
(Etype
(Subtype_Mark
(DS
))));
3171 -- Check for null or possibly null range and issue warning. We
3172 -- suppress such messages in generic templates and instances,
3173 -- because in practice they tend to be dubious in these cases. The
3174 -- check applies as well to rewritten array element loops where a
3175 -- null range may be detected statically.
3177 if Compile_Time_Compare
(L
, H
, Assume_Valid
=> True) = GT
then
3179 -- Suppress the warning if inside a generic template or
3180 -- instance, since in practice they tend to be dubious in these
3181 -- cases since they can result from intended parameterization.
3183 if not Inside_A_Generic
and then not In_Instance
then
3185 -- Specialize msg if invalid values could make the loop
3186 -- non-null after all.
3188 if Compile_Time_Compare
3189 (L
, H
, Assume_Valid
=> False) = GT
3191 -- Since we know the range of the loop is null, set the
3192 -- appropriate flag to remove the loop entirely during
3195 Set_Is_Null_Loop
(Loop_Nod
);
3197 if Comes_From_Source
(N
) then
3199 ("??loop range is null, loop will not execute", DS
);
3202 -- Here is where the loop could execute because of
3203 -- invalid values, so issue appropriate message and in
3204 -- this case we do not set the Is_Null_Loop flag since
3205 -- the loop may execute.
3207 elsif Comes_From_Source
(N
) then
3209 ("??loop range may be null, loop may not execute",
3212 ("??can only execute if invalid values are present",
3217 -- In either case, suppress warnings in the body of the loop,
3218 -- since it is likely that these warnings will be inappropriate
3219 -- if the loop never actually executes, which is likely.
3221 Set_Suppress_Loop_Warnings
(Loop_Nod
);
3223 -- The other case for a warning is a reverse loop where the
3224 -- upper bound is the integer literal zero or one, and the
3225 -- lower bound may exceed this value.
3227 -- For example, we have
3229 -- for J in reverse N .. 1 loop
3231 -- In practice, this is very likely to be a case of reversing
3232 -- the bounds incorrectly in the range.
3234 elsif Reverse_Present
(N
)
3235 and then Nkind
(Original_Node
(H
)) = N_Integer_Literal
3237 (Intval
(Original_Node
(H
)) = Uint_0
3239 Intval
(Original_Node
(H
)) = Uint_1
)
3241 -- Lower bound may in fact be known and known not to exceed
3242 -- upper bound (e.g. reverse 0 .. 1) and that's OK.
3244 if Compile_Time_Known_Value
(L
)
3245 and then Expr_Value
(L
) <= Expr_Value
(H
)
3249 -- Otherwise warning is warranted
3252 Error_Msg_N
("??loop range may be null", DS
);
3253 Error_Msg_N
("\??bounds may be wrong way round", DS
);
3257 -- Check if either bound is known to be outside the range of the
3258 -- loop parameter type, this is e.g. the case of a loop from
3259 -- 20..X where the type is 1..19.
3261 -- Such a loop is dubious since either it raises CE or it executes
3262 -- zero times, and that cannot be useful!
3264 if Etype
(DS
) /= Any_Type
3265 and then not Error_Posted
(DS
)
3266 and then Nkind
(DS
) = N_Subtype_Indication
3267 and then Nkind
(Constraint
(DS
)) = N_Range_Constraint
3270 LLo
: constant Node_Id
:=
3271 Low_Bound
(Range_Expression
(Constraint
(DS
)));
3272 LHi
: constant Node_Id
:=
3273 High_Bound
(Range_Expression
(Constraint
(DS
)));
3275 Bad_Bound
: Node_Id
:= Empty
;
3276 -- Suspicious loop bound
3279 -- At this stage L, H are the bounds of the type, and LLo
3280 -- Lhi are the low bound and high bound of the loop.
3282 if Compile_Time_Compare
(LLo
, L
, Assume_Valid
=> True) = LT
3284 Compile_Time_Compare
(LLo
, H
, Assume_Valid
=> True) = GT
3289 if Compile_Time_Compare
(LHi
, L
, Assume_Valid
=> True) = LT
3291 Compile_Time_Compare
(LHi
, H
, Assume_Valid
=> True) = GT
3296 if Present
(Bad_Bound
) then
3298 ("suspicious loop bound out of range of "
3299 & "loop subtype??", Bad_Bound
);
3301 ("\loop executes zero times or raises "
3302 & "Constraint_Error??", Bad_Bound
);
3307 -- This declare block is about warnings, if we get an exception while
3308 -- testing for warnings, we simply abandon the attempt silently. This
3309 -- most likely occurs as the result of a previous error, but might
3310 -- just be an obscure case we have missed. In either case, not giving
3311 -- the warning is perfectly acceptable.
3314 when others => null;
3318 -- A loop parameter cannot be effectively volatile (SPARK RM 7.1.3(4)).
3319 -- This check is relevant only when SPARK_Mode is on as it is not a
3320 -- standard Ada legality check.
3322 if SPARK_Mode
= On
and then Is_Effectively_Volatile
(Id
) then
3323 Error_Msg_N
("loop parameter cannot be volatile", Id
);
3325 end Analyze_Loop_Parameter_Specification
;
3327 ----------------------------
3328 -- Analyze_Loop_Statement --
3329 ----------------------------
3331 procedure Analyze_Loop_Statement
(N
: Node_Id
) is
3333 function Is_Container_Iterator
(Iter
: Node_Id
) return Boolean;
3334 -- Given a loop iteration scheme, determine whether it is an Ada 2012
3335 -- container iteration.
3337 function Is_Wrapped_In_Block
(N
: Node_Id
) return Boolean;
3338 -- Determine whether loop statement N has been wrapped in a block to
3339 -- capture finalization actions that may be generated for container
3340 -- iterators. Prevents infinite recursion when block is analyzed.
3341 -- Routine is a noop if loop is single statement within source block.
3343 ---------------------------
3344 -- Is_Container_Iterator --
3345 ---------------------------
3347 function Is_Container_Iterator
(Iter
: Node_Id
) return Boolean is
3356 elsif Present
(Condition
(Iter
)) then
3359 -- for Def_Id in [reverse] Name loop
3360 -- for Def_Id [: Subtype_Indication] of [reverse] Name loop
3362 elsif Present
(Iterator_Specification
(Iter
)) then
3364 Nam
: constant Node_Id
:= Name
(Iterator_Specification
(Iter
));
3368 Nam_Copy
:= New_Copy_Tree
(Nam
);
3369 Set_Parent
(Nam_Copy
, Parent
(Nam
));
3370 Preanalyze_Range
(Nam_Copy
);
3372 -- The only two options here are iteration over a container or
3375 return not Is_Array_Type
(Etype
(Nam_Copy
));
3378 -- for Def_Id in [reverse] Discrete_Subtype_Definition loop
3382 LP
: constant Node_Id
:= Loop_Parameter_Specification
(Iter
);
3383 DS
: constant Node_Id
:= Discrete_Subtype_Definition
(LP
);
3387 DS_Copy
:= New_Copy_Tree
(DS
);
3388 Set_Parent
(DS_Copy
, Parent
(DS
));
3389 Preanalyze_Range
(DS_Copy
);
3391 -- Check for a call to Iterate () or an expression with
3392 -- an iterator type.
3395 (Nkind
(DS_Copy
) = N_Function_Call
3396 and then Needs_Finalization
(Etype
(DS_Copy
)))
3397 or else Is_Iterator
(Etype
(DS_Copy
));
3400 end Is_Container_Iterator
;
3402 -------------------------
3403 -- Is_Wrapped_In_Block --
3404 -------------------------
3406 function Is_Wrapped_In_Block
(N
: Node_Id
) return Boolean is
3412 -- Check if current scope is a block that is not a transient block.
3414 if Ekind
(Current_Scope
) /= E_Block
3415 or else No
(Block_Node
(Current_Scope
))
3421 Handled_Statement_Sequence
(Parent
(Block_Node
(Current_Scope
)));
3423 -- Skip leading pragmas that may be introduced for invariant and
3424 -- predicate checks.
3426 Stat
:= First
(Statements
(HSS
));
3427 while Present
(Stat
) and then Nkind
(Stat
) = N_Pragma
loop
3428 Stat
:= Next
(Stat
);
3431 return Stat
= N
and then No
(Next
(Stat
));
3433 end Is_Wrapped_In_Block
;
3435 -- Local declarations
3437 Id
: constant Node_Id
:= Identifier
(N
);
3438 Iter
: constant Node_Id
:= Iteration_Scheme
(N
);
3439 Loc
: constant Source_Ptr
:= Sloc
(N
);
3443 -- Start of processing for Analyze_Loop_Statement
3446 if Present
(Id
) then
3448 -- Make name visible, e.g. for use in exit statements. Loop labels
3449 -- are always considered to be referenced.
3454 -- Guard against serious error (typically, a scope mismatch when
3455 -- semantic analysis is requested) by creating loop entity to
3456 -- continue analysis.
3459 if Total_Errors_Detected
/= 0 then
3460 Ent
:= New_Internal_Entity
(E_Loop
, Current_Scope
, Loc
, 'L');
3462 raise Program_Error
;
3465 -- Verify that the loop name is hot hidden by an unrelated
3466 -- declaration in an inner scope.
3468 elsif Ekind
(Ent
) /= E_Label
and then Ekind
(Ent
) /= E_Loop
then
3469 Error_Msg_Sloc
:= Sloc
(Ent
);
3470 Error_Msg_N
("implicit label declaration for & is hidden#", Id
);
3472 if Present
(Homonym
(Ent
))
3473 and then Ekind
(Homonym
(Ent
)) = E_Label
3475 Set_Entity
(Id
, Ent
);
3476 Set_Ekind
(Ent
, E_Loop
);
3480 Generate_Reference
(Ent
, N
, ' ');
3481 Generate_Definition
(Ent
);
3483 -- If we found a label, mark its type. If not, ignore it, since it
3484 -- means we have a conflicting declaration, which would already
3485 -- have been diagnosed at declaration time. Set Label_Construct
3486 -- of the implicit label declaration, which is not created by the
3487 -- parser for generic units.
3489 if Ekind
(Ent
) = E_Label
then
3490 Set_Ekind
(Ent
, E_Loop
);
3492 if Nkind
(Parent
(Ent
)) = N_Implicit_Label_Declaration
then
3493 Set_Label_Construct
(Parent
(Ent
), N
);
3498 -- Case of no identifier present. Create one and attach it to the
3499 -- loop statement for use as a scope and as a reference for later
3500 -- expansions. Indicate that the label does not come from source,
3501 -- and attach it to the loop statement so it is part of the tree,
3502 -- even without a full declaration.
3505 Ent
:= New_Internal_Entity
(E_Loop
, Current_Scope
, Loc
, 'L');
3506 Set_Etype
(Ent
, Standard_Void_Type
);
3507 Set_Identifier
(N
, New_Occurrence_Of
(Ent
, Loc
));
3508 Set_Parent
(Ent
, N
);
3509 Set_Has_Created_Identifier
(N
);
3512 -- If the iterator specification has a syntactic error, transform
3513 -- construct into an infinite loop to prevent a crash and perform
3517 and then Present
(Iterator_Specification
(Iter
))
3518 and then Error_Posted
(Iterator_Specification
(Iter
))
3520 Set_Iteration_Scheme
(N
, Empty
);
3525 -- Iteration over a container in Ada 2012 involves the creation of a
3526 -- controlled iterator object. Wrap the loop in a block to ensure the
3527 -- timely finalization of the iterator and release of container locks.
3528 -- The same applies to the use of secondary stack when obtaining an
3531 if Ada_Version
>= Ada_2012
3532 and then Is_Container_Iterator
(Iter
)
3533 and then not Is_Wrapped_In_Block
(N
)
3536 Block_Nod
: Node_Id
;
3537 Block_Id
: Entity_Id
;
3541 Make_Block_Statement
(Loc
,
3542 Declarations
=> New_List
,
3543 Handled_Statement_Sequence
=>
3544 Make_Handled_Sequence_Of_Statements
(Loc
,
3545 Statements
=> New_List
(Relocate_Node
(N
))));
3547 Add_Block_Identifier
(Block_Nod
, Block_Id
);
3549 -- The expansion of iterator loops generates an iterator in order
3550 -- to traverse the elements of a container:
3552 -- Iter : <iterator type> := Iterate (Container)'reference;
3554 -- The iterator is controlled and returned on the secondary stack.
3555 -- The analysis of the call to Iterate establishes a transient
3556 -- scope to deal with the secondary stack management, but never
3557 -- really creates a physical block as this would kill the iterator
3558 -- too early (see Wrap_Transient_Declaration). To address this
3559 -- case, mark the generated block as needing secondary stack
3562 Set_Uses_Sec_Stack
(Block_Id
);
3564 Rewrite
(N
, Block_Nod
);
3570 -- Kill current values on entry to loop, since statements in the body of
3571 -- the loop may have been executed before the loop is entered. Similarly
3572 -- we kill values after the loop, since we do not know that the body of
3573 -- the loop was executed.
3575 Kill_Current_Values
;
3577 Analyze_Iteration_Scheme
(Iter
);
3579 -- Check for following case which merits a warning if the type E of is
3580 -- a multi-dimensional array (and no explicit subscript ranges present).
3586 and then Present
(Loop_Parameter_Specification
(Iter
))
3589 LPS
: constant Node_Id
:= Loop_Parameter_Specification
(Iter
);
3590 DSD
: constant Node_Id
:=
3591 Original_Node
(Discrete_Subtype_Definition
(LPS
));
3593 if Nkind
(DSD
) = N_Attribute_Reference
3594 and then Attribute_Name
(DSD
) = Name_Range
3595 and then No
(Expressions
(DSD
))
3598 Typ
: constant Entity_Id
:= Etype
(Prefix
(DSD
));
3600 if Is_Array_Type
(Typ
)
3601 and then Number_Dimensions
(Typ
) > 1
3602 and then Nkind
(Parent
(N
)) = N_Loop_Statement
3603 and then Present
(Iteration_Scheme
(Parent
(N
)))
3606 OIter
: constant Node_Id
:=
3607 Iteration_Scheme
(Parent
(N
));
3608 OLPS
: constant Node_Id
:=
3609 Loop_Parameter_Specification
(OIter
);
3610 ODSD
: constant Node_Id
:=
3611 Original_Node
(Discrete_Subtype_Definition
(OLPS
));
3613 if Nkind
(ODSD
) = N_Attribute_Reference
3614 and then Attribute_Name
(ODSD
) = Name_Range
3615 and then No
(Expressions
(ODSD
))
3616 and then Etype
(Prefix
(ODSD
)) = Typ
3618 Error_Msg_Sloc
:= Sloc
(ODSD
);
3620 ("inner range same as outer range#??", DSD
);
3629 -- Analyze the statements of the body except in the case of an Ada 2012
3630 -- iterator with the expander active. In this case the expander will do
3631 -- a rewrite of the loop into a while loop. We will then analyze the
3632 -- loop body when we analyze this while loop.
3634 -- We need to do this delay because if the container is for indefinite
3635 -- types the actual subtype of the components will only be determined
3636 -- when the cursor declaration is analyzed.
3638 -- If the expander is not active then we want to analyze the loop body
3639 -- now even in the Ada 2012 iterator case, since the rewriting will not
3640 -- be done. Insert the loop variable in the current scope, if not done
3641 -- when analysing the iteration scheme. Set its kind properly to detect
3642 -- improper uses in the loop body.
3644 -- In GNATprove mode, we do one of the above depending on the kind of
3645 -- loop. If it is an iterator over an array, then we do not analyze the
3646 -- loop now. We will analyze it after it has been rewritten by the
3647 -- special SPARK expansion which is activated in GNATprove mode. We need
3648 -- to do this so that other expansions that should occur in GNATprove
3649 -- mode take into account the specificities of the rewritten loop, in
3650 -- particular the introduction of a renaming (which needs to be
3653 -- In other cases in GNATprove mode then we want to analyze the loop
3654 -- body now, since no rewriting will occur. Within a generic the
3655 -- GNATprove mode is irrelevant, we must analyze the generic for
3656 -- non-local name capture.
3659 and then Present
(Iterator_Specification
(Iter
))
3662 and then Is_Iterator_Over_Array
(Iterator_Specification
(Iter
))
3663 and then not Inside_A_Generic
3667 elsif not Expander_Active
then
3669 I_Spec
: constant Node_Id
:= Iterator_Specification
(Iter
);
3670 Id
: constant Entity_Id
:= Defining_Identifier
(I_Spec
);
3673 if Scope
(Id
) /= Current_Scope
then
3677 -- In an element iterator, The loop parameter is a variable if
3678 -- the domain of iteration (container or array) is a variable.
3680 if not Of_Present
(I_Spec
)
3681 or else not Is_Variable
(Name
(I_Spec
))
3683 Set_Ekind
(Id
, E_Loop_Parameter
);
3687 Analyze_Statements
(Statements
(N
));
3691 -- Pre-Ada2012 for-loops and while loops
3693 Analyze_Statements
(Statements
(N
));
3696 -- When the iteration scheme of a loop contains attribute 'Loop_Entry,
3697 -- the loop is transformed into a conditional block. Retrieve the loop.
3701 if Subject_To_Loop_Entry_Attributes
(Stmt
) then
3702 Stmt
:= Find_Loop_In_Conditional_Block
(Stmt
);
3705 -- Finish up processing for the loop. We kill all current values, since
3706 -- in general we don't know if the statements in the loop have been
3707 -- executed. We could do a bit better than this with a loop that we
3708 -- know will execute at least once, but it's not worth the trouble and
3709 -- the front end is not in the business of flow tracing.
3711 Process_End_Label
(Stmt
, 'e', Ent
);
3713 Kill_Current_Values
;
3715 -- Check for infinite loop. Skip check for generated code, since it
3716 -- justs waste time and makes debugging the routine called harder.
3718 -- Note that we have to wait till the body of the loop is fully analyzed
3719 -- before making this call, since Check_Infinite_Loop_Warning relies on
3720 -- being able to use semantic visibility information to find references.
3722 if Comes_From_Source
(Stmt
) then
3723 Check_Infinite_Loop_Warning
(Stmt
);
3726 -- Code after loop is unreachable if the loop has no WHILE or FOR and
3727 -- contains no EXIT statements within the body of the loop.
3729 if No
(Iter
) and then not Has_Exit
(Ent
) then
3730 Check_Unreachable_Code
(Stmt
);
3732 end Analyze_Loop_Statement
;
3734 ----------------------------
3735 -- Analyze_Null_Statement --
3736 ----------------------------
3738 -- Note: the semantics of the null statement is implemented by a single
3739 -- null statement, too bad everything isn't as simple as this.
3741 procedure Analyze_Null_Statement
(N
: Node_Id
) is
3742 pragma Warnings
(Off
, N
);
3745 end Analyze_Null_Statement
;
3747 -------------------------
3748 -- Analyze_Target_Name --
3749 -------------------------
3751 procedure Analyze_Target_Name
(N
: Node_Id
) is
3753 -- A target name has the type of the left-hand side of the enclosing
3756 Set_Etype
(N
, Etype
(Name
(Current_Assignment
)));
3757 end Analyze_Target_Name
;
3759 ------------------------
3760 -- Analyze_Statements --
3761 ------------------------
3763 procedure Analyze_Statements
(L
: List_Id
) is
3768 -- The labels declared in the statement list are reachable from
3769 -- statements in the list. We do this as a prepass so that any goto
3770 -- statement will be properly flagged if its target is not reachable.
3771 -- This is not required, but is nice behavior.
3774 while Present
(S
) loop
3775 if Nkind
(S
) = N_Label
then
3776 Analyze
(Identifier
(S
));
3777 Lab
:= Entity
(Identifier
(S
));
3779 -- If we found a label mark it as reachable
3781 if Ekind
(Lab
) = E_Label
then
3782 Generate_Definition
(Lab
);
3783 Set_Reachable
(Lab
);
3785 if Nkind
(Parent
(Lab
)) = N_Implicit_Label_Declaration
then
3786 Set_Label_Construct
(Parent
(Lab
), S
);
3789 -- If we failed to find a label, it means the implicit declaration
3790 -- of the label was hidden. A for-loop parameter can do this to
3791 -- a label with the same name inside the loop, since the implicit
3792 -- label declaration is in the innermost enclosing body or block
3796 Error_Msg_Sloc
:= Sloc
(Lab
);
3798 ("implicit label declaration for & is hidden#",
3806 -- Perform semantic analysis on all statements
3808 Conditional_Statements_Begin
;
3811 while Present
(S
) loop
3814 -- Remove dimension in all statements
3816 Remove_Dimension_In_Statement
(S
);
3820 Conditional_Statements_End
;
3822 -- Make labels unreachable. Visibility is not sufficient, because labels
3823 -- in one if-branch for example are not reachable from the other branch,
3824 -- even though their declarations are in the enclosing declarative part.
3827 while Present
(S
) loop
3828 if Nkind
(S
) = N_Label
then
3829 Set_Reachable
(Entity
(Identifier
(S
)), False);
3834 end Analyze_Statements
;
3836 ----------------------------
3837 -- Check_Unreachable_Code --
3838 ----------------------------
3840 procedure Check_Unreachable_Code
(N
: Node_Id
) is
3841 Error_Node
: Node_Id
;
3845 if Is_List_Member
(N
) and then Comes_From_Source
(N
) then
3850 Nxt
:= Original_Node
(Next
(N
));
3852 -- Skip past pragmas
3854 while Nkind
(Nxt
) = N_Pragma
loop
3855 Nxt
:= Original_Node
(Next
(Nxt
));
3858 -- If a label follows us, then we never have dead code, since
3859 -- someone could branch to the label, so we just ignore it, unless
3860 -- we are in formal mode where goto statements are not allowed.
3862 if Nkind
(Nxt
) = N_Label
3863 and then not Restriction_Check_Required
(SPARK_05
)
3867 -- Otherwise see if we have a real statement following us
3870 and then Comes_From_Source
(Nxt
)
3871 and then Is_Statement
(Nxt
)
3873 -- Special very annoying exception. If we have a return that
3874 -- follows a raise, then we allow it without a warning, since
3875 -- the Ada RM annoyingly requires a useless return here.
3877 if Nkind
(Original_Node
(N
)) /= N_Raise_Statement
3878 or else Nkind
(Nxt
) /= N_Simple_Return_Statement
3880 -- The rather strange shenanigans with the warning message
3881 -- here reflects the fact that Kill_Dead_Code is very good
3882 -- at removing warnings in deleted code, and this is one
3883 -- warning we would prefer NOT to have removed.
3887 -- If we have unreachable code, analyze and remove the
3888 -- unreachable code, since it is useless and we don't
3889 -- want to generate junk warnings.
3891 -- We skip this step if we are not in code generation mode
3892 -- or CodePeer mode.
3894 -- This is the one case where we remove dead code in the
3895 -- semantics as opposed to the expander, and we do not want
3896 -- to remove code if we are not in code generation mode,
3897 -- since this messes up the ASIS trees or loses useful
3898 -- information in the CodePeer tree.
3900 -- Note that one might react by moving the whole circuit to
3901 -- exp_ch5, but then we lose the warning in -gnatc mode.
3903 if Operating_Mode
= Generate_Code
3904 and then not CodePeer_Mode
3909 -- Quit deleting when we have nothing more to delete
3910 -- or if we hit a label (since someone could transfer
3911 -- control to a label, so we should not delete it).
3913 exit when No
(Nxt
) or else Nkind
(Nxt
) = N_Label
;
3915 -- Statement/declaration is to be deleted
3919 Kill_Dead_Code
(Nxt
);
3923 -- Now issue the warning (or error in formal mode)
3925 if Restriction_Check_Required
(SPARK_05
) then
3926 Check_SPARK_05_Restriction
3927 ("unreachable code is not allowed", Error_Node
);
3930 ("??unreachable code!", Sloc
(Error_Node
), Error_Node
);
3934 -- If the unconditional transfer of control instruction is the
3935 -- last statement of a sequence, then see if our parent is one of
3936 -- the constructs for which we count unblocked exits, and if so,
3937 -- adjust the count.
3942 -- Statements in THEN part or ELSE part of IF statement
3944 if Nkind
(P
) = N_If_Statement
then
3947 -- Statements in ELSIF part of an IF statement
3949 elsif Nkind
(P
) = N_Elsif_Part
then
3951 pragma Assert
(Nkind
(P
) = N_If_Statement
);
3953 -- Statements in CASE statement alternative
3955 elsif Nkind
(P
) = N_Case_Statement_Alternative
then
3957 pragma Assert
(Nkind
(P
) = N_Case_Statement
);
3959 -- Statements in body of block
3961 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
3962 and then Nkind
(Parent
(P
)) = N_Block_Statement
3964 -- The original loop is now placed inside a block statement
3965 -- due to the expansion of attribute 'Loop_Entry. Return as
3966 -- this is not a "real" block for the purposes of exit
3969 if Nkind
(N
) = N_Loop_Statement
3970 and then Subject_To_Loop_Entry_Attributes
(N
)
3975 -- Statements in exception handler in a block
3977 elsif Nkind
(P
) = N_Exception_Handler
3978 and then Nkind
(Parent
(P
)) = N_Handled_Sequence_Of_Statements
3979 and then Nkind
(Parent
(Parent
(P
))) = N_Block_Statement
3983 -- None of these cases, so return
3989 -- This was one of the cases we are looking for (i.e. the
3990 -- parent construct was IF, CASE or block) so decrement count.
3992 Unblocked_Exit_Count
:= Unblocked_Exit_Count
- 1;
3996 end Check_Unreachable_Code
;
3998 ----------------------
3999 -- Preanalyze_Range --
4000 ----------------------
4002 procedure Preanalyze_Range
(R_Copy
: Node_Id
) is
4003 Save_Analysis
: constant Boolean := Full_Analysis
;
4007 Full_Analysis
:= False;
4008 Expander_Mode_Save_And_Set
(False);
4012 if Nkind
(R_Copy
) in N_Subexpr
and then Is_Overloaded
(R_Copy
) then
4014 -- Apply preference rules for range of predefined integer types, or
4015 -- check for array or iterable construct for "of" iterator, or
4016 -- diagnose true ambiguity.
4021 Found
: Entity_Id
:= Empty
;
4024 Get_First_Interp
(R_Copy
, I
, It
);
4025 while Present
(It
.Typ
) loop
4026 if Is_Discrete_Type
(It
.Typ
) then
4030 if Scope
(Found
) = Standard_Standard
then
4033 elsif Scope
(It
.Typ
) = Standard_Standard
then
4037 -- Both of them are user-defined
4040 ("ambiguous bounds in range of iteration", R_Copy
);
4041 Error_Msg_N
("\possible interpretations:", R_Copy
);
4042 Error_Msg_NE
("\\} ", R_Copy
, Found
);
4043 Error_Msg_NE
("\\} ", R_Copy
, It
.Typ
);
4048 elsif Nkind
(Parent
(R_Copy
)) = N_Iterator_Specification
4049 and then Of_Present
(Parent
(R_Copy
))
4051 if Is_Array_Type
(It
.Typ
)
4052 or else Has_Aspect
(It
.Typ
, Aspect_Iterator_Element
)
4053 or else Has_Aspect
(It
.Typ
, Aspect_Constant_Indexing
)
4054 or else Has_Aspect
(It
.Typ
, Aspect_Variable_Indexing
)
4058 Set_Etype
(R_Copy
, It
.Typ
);
4061 Error_Msg_N
("ambiguous domain of iteration", R_Copy
);
4066 Get_Next_Interp
(I
, It
);
4071 -- Subtype mark in iteration scheme
4073 if Is_Entity_Name
(R_Copy
) and then Is_Type
(Entity
(R_Copy
)) then
4076 -- Expression in range, or Ada 2012 iterator
4078 elsif Nkind
(R_Copy
) in N_Subexpr
then
4080 Typ
:= Etype
(R_Copy
);
4082 if Is_Discrete_Type
(Typ
) then
4085 -- Check that the resulting object is an iterable container
4087 elsif Has_Aspect
(Typ
, Aspect_Iterator_Element
)
4088 or else Has_Aspect
(Typ
, Aspect_Constant_Indexing
)
4089 or else Has_Aspect
(Typ
, Aspect_Variable_Indexing
)
4093 -- The expression may yield an implicit reference to an iterable
4094 -- container. Insert explicit dereference so that proper type is
4095 -- visible in the loop.
4097 elsif Has_Implicit_Dereference
(Etype
(R_Copy
)) then
4102 Disc
:= First_Discriminant
(Typ
);
4103 while Present
(Disc
) loop
4104 if Has_Implicit_Dereference
(Disc
) then
4105 Build_Explicit_Dereference
(R_Copy
, Disc
);
4109 Next_Discriminant
(Disc
);
4116 Expander_Mode_Restore
;
4117 Full_Analysis
:= Save_Analysis
;
4118 end Preanalyze_Range
;