-- like a potential bug ???
procedure Force_Evaluation
- (Exp : Node_Id;
- Name_Req : Boolean := False);
+ (Exp : Node_Id;
+ Name_Req : Boolean := False;
+ Related_Id : Entity_Id := Empty;
+ Is_Low_Bound : Boolean := False;
+ Is_High_Bound : Boolean := False);
-- Force the evaluation of the expression right away. Similar behavior
-- to Remove_Side_Effects when Variable_Ref is set to TRUE. That is to
- -- say, it removes the side-effects and captures the values of the
+ -- say, it removes the side effects and captures the values of the
-- variables. Remove_Side_Effects guarantees that multiple evaluations
-- of the same expression won't generate multiple side effects, whereas
-- Force_Evaluation further guarantees that all evaluations will yield
-- the same result.
+ --
+ -- Related_Id denotes the entity of the context where Expr appears. Flags
+ -- Is_Low_Bound and Is_High_Bound specify whether the expression to check
+ -- is the low or the high bound of a range. These three optional arguments
+ -- signal Remove_Side_Effects to create an external symbol of the form
+ -- Chars (Related_Id)_FIRST/_LAST. If Related_Id is set, then exactly one
+ -- of the Is_xxx_Bound flags must be set. For use of these parameters see
+ -- the warning in the body of Sem_Ch3.Process_Range_Expr_In_Decl.
function Fully_Qualified_Name_String
(E : Entity_Id;
while Present (C) loop
Expr := Node (C);
- -- It is safe here to call New_Copy_Tree since
- -- Force_Evaluation was called on each constraint in
- -- Build_Discriminant_Constraints.
+ -- It is safe here to call New_Copy_Tree since we called
+ -- Force_Evaluation on each constraint previously
+ -- in Build_Discriminant_Constraints.
Append (New_Copy_Tree (Expr), To => Constr_List);
-- supposed to occur, e.g. on default parameters of a call.
if Expander_Active or GNATprove_Mode then
- Force_Evaluation (Low_Bound (R));
- Force_Evaluation (High_Bound (R));
+ Force_Evaluation
+ (Low_Bound (R), Related_Id => Related_Id, Is_Low_Bound => True);
+ Force_Evaluation
+ (High_Bound (R), Related_Id => Related_Id, Is_Low_Bound => True);
end if;
elsif Nkind (S) = N_Discriminant_Association then
if Expander_Active or GNATprove_Mode then
- -- If no subtype name, then just call Force_Evaluation to
- -- create declarations as needed to deal with side effects.
- -- Also ignore calls from within a record type, where we
- -- have possible scoping issues.
-
- if No (Subtyp) or else Is_Record_Type (Current_Scope) then
- Force_Evaluation (Lo);
- Force_Evaluation (Hi);
-
- -- If a subtype is given, then we capture the bounds if they
- -- are not known at compile time, using constant identifiers
- -- xxx_FIRST and xxx_LAST where xxx is the name of the subtype.
+ -- Call Force_Evaluation to create declarations as needed to
+ -- deal with side effects, and also create typ_FIRST/LAST
+ -- entities for bounds if we have a subtype name.
-- Note: we do this transformation even if expansion is not
- -- active, and in particular we do it in GNATprove_Mode since
- -- the transformation is in general required to ensure that the
- -- resulting tree has proper Ada semantics.
-
- -- Historical note: We used to just do Force_Evaluation calls
- -- in all cases, but it is better to capture the bounds with
- -- proper non-serialized names, since these will be accessed
- -- from other units, and hence may be public, and also we can
- -- then expand 'First and 'Last references to be references to
- -- these special names.
-
- else
- if not Compile_Time_Known_Value (Lo)
-
- -- No need to capture bounds if they already are
- -- references to constants.
-
- and then not (Is_Entity_Name (Lo)
- and then Is_Constant_Object (Entity (Lo)))
- then
- declare
- Loc : constant Source_Ptr := Sloc (Lo);
- Lov : constant Entity_Id :=
- Make_Defining_Identifier (Loc,
- Chars =>
- New_External_Name (Chars (Subtyp), "_FIRST"));
- begin
- Insert_Action (R,
- Make_Object_Declaration (Loc,
- Defining_Identifier => Lov,
- Object_Definition =>
- New_Occurrence_Of (Base_Type (T), Loc),
- Constant_Present => True,
- Expression => Relocate_Node (Lo)));
- Rewrite (Lo, New_Occurrence_Of (Lov, Loc));
- end;
- end if;
-
- if not Compile_Time_Known_Value (Hi)
- and then not (Is_Entity_Name (Hi)
- and then Is_Constant_Object (Entity (Hi)))
- then
- declare
- Loc : constant Source_Ptr := Sloc (Hi);
- Hiv : constant Entity_Id :=
- Make_Defining_Identifier (Loc,
- Chars =>
- New_External_Name (Chars (Subtyp), "_LAST"));
- begin
- Insert_Action (R,
- Make_Object_Declaration (Loc,
- Defining_Identifier => Hiv,
- Object_Definition =>
- New_Occurrence_Of (Base_Type (T), Loc),
- Constant_Present => True,
- Expression => Relocate_Node (Hi)));
- Rewrite (Hi, New_Occurrence_Of (Hiv, Loc));
- end;
- end if;
- end if;
+ -- active if we are in GNATprove_Mode since the transformation
+ -- is in general required to ensure that the resulting tree has
+ -- proper Ada semantics.
+
+ Force_Evaluation
+ (Lo, Related_Id => Subtyp, Is_Low_Bound => True);
+ Force_Evaluation
+ (Hi, Related_Id => Subtyp, Is_High_Bound => True);
end if;
-- We use a flag here instead of suppressing checks on the
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