[multiple changes]
2017-01-06 Ed Schonberg <schonberg@adacore.com> * sem_eval.adb (Check_Expression_Against_Static_Predicate): If expression is compile-time known and obeys a static predicate it must be labelled as static, to prevent spurious warnings and run-time errors, e.g. in case statements. This is relevant when the expression is the result of constant-folding a type conversion whose expression is a variable with a known static value. 2017-01-06 Hristian Kirtchev <kirtchev@adacore.com> * exp_attr.adb, sem_attr.ads: Minor reformatting. From-SVN: r244135
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Arnaud Charlet
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d9c59db455
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@ -1,3 +1,16 @@
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2017-01-06 Ed Schonberg <schonberg@adacore.com>
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* sem_eval.adb (Check_Expression_Against_Static_Predicate):
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If expression is compile-time known and obeys a static predicate
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it must be labelled as static, to prevent spurious warnings and
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run-time errors, e.g. in case statements. This is relevant when
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the expression is the result of constant-folding a type conversion
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whose expression is a variable with a known static value.
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2017-01-06 Hristian Kirtchev <kirtchev@adacore.com>
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* exp_attr.adb, sem_attr.ads: Minor reformatting.
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2017-01-06 Justin Squirek <squirek@adacore.com>
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* exp_attr.adb (Expand_N_Attribute_Reference): Add entry for
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@ -3141,11 +3141,10 @@ package body Exp_Attr is
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-----------------------
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when Attribute_Finalization_Size => Finalization_Size : declare
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function Calculate_Header_Size return Node_Id;
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-- Generate a runtime call to calculate the size of the hidden
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-- header along with any added padding which would precede a
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-- heap-allocated object of the prefix type.
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-- Generate a runtime call to calculate the size of the hidden header
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-- along with any added padding which would precede a heap-allocated
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-- object of the prefix type.
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---------------------------
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-- Calculate_Header_Size --
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@ -3155,46 +3154,47 @@ package body Exp_Attr is
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begin
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-- Generate:
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-- Universal_Integer
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-- (Header_Size_With_Padding (N'Alignment))
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-- (Header_Size_With_Padding (Pref'Alignment))
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return
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Convert_To (Universal_Integer,
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Make_Function_Call (Loc,
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Name =>
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New_Occurrence_Of
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(RTE (RE_Header_Size_With_Padding), Loc),
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New_Occurrence_Of (RTE (RE_Header_Size_With_Padding), Loc),
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Parameter_Associations => New_List (
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Make_Attribute_Reference (Loc,
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Prefix =>
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New_Copy_Tree (Pref),
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Prefix => New_Copy_Tree (Pref),
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Attribute_Name => Name_Alignment))));
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end Calculate_Header_Size;
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-- Local variables
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-- Local variables
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Size : constant Entity_Id := Make_Temporary (Loc, 'S');
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Size : Entity_Id;
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-- Start of Finalization_Size
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begin
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-- An object of a class-wide type requires a runtime check to
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-- An object of a class-wide type first requires a runtime check to
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-- determine whether it is actually controlled or not. Depending on
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-- the outcome of this check, the Finalization_Size of the object
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-- may be zero or some positive value.
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--
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-- In this scenario, Obj'Finalization_Size is expanded into
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-- In this scenario, Pref'Finalization_Size is expanded into
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--
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-- Size : Integer := 0;
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-- Size : Integer := 0;
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--
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-- if Needs_Finalization (Pref'Tag) then
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-- Size :=
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-- Universal_Integer
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-- (Header_Size_With_Padding (Pref'Alignment));
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-- end if;
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-- if Needs_Finalization (Pref'Tag) then
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-- Size :=
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-- Universal_Integer
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-- (Header_Size_With_Padding (Pref'Alignment));
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-- end if;
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--
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-- and the attribute reference is replaced with a reference to Size.
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if Is_Class_Wide_Type (Ptyp) then
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Size := Make_Temporary (Loc, 'S');
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Insert_Actions (N, New_List (
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-- Generate:
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@ -3208,21 +3208,22 @@ package body Exp_Attr is
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-- Generate:
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-- if Needs_Finalization (Pref'Tag) then
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-- Size := Universal_Integer
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-- (Header_Size_With_Padding (Pref'Alignment));
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-- Size :=
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-- Universal_Integer
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-- (Header_Size_With_Padding (Pref'Alignment));
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-- end if;
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Make_If_Statement (Loc,
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Condition =>
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Make_Function_Call (Loc,
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Name =>
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New_Occurrence_Of
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(RTE (RE_Needs_Finalization), Loc),
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New_Occurrence_Of (RTE (RE_Needs_Finalization), Loc),
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Parameter_Associations => New_List (
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Make_Attribute_Reference (Loc,
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Attribute_Name => Name_Tag,
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Prefix =>
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New_Copy_Tree (Pref)))),
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Prefix => New_Copy_Tree (Pref),
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Attribute_Name => Name_Tag))),
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Then_Statements => New_List (
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Make_Assignment_Statement (Loc,
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Name => New_Occurrence_Of (Size, Loc),
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@ -3230,15 +3231,14 @@ package body Exp_Attr is
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Rewrite (N, New_Occurrence_Of (Size, Loc));
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-- The the prefix is known to be controlled at compile time.
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-- Calculate its Finalization_Size by calling runtime routine
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-- Header_Size_With_Padding.
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-- The prefix is known to be controlled at compile time. Calculate
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-- Finalization_Size by calling function Header_Size_With_Padding.
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elsif Needs_Finalization (Ptyp) then
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Rewrite (N, Calculate_Header_Size);
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-- The prefix is not a controlled object, its Finalization_Size
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-- is zero.
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-- The prefix is not an object with controlled parts, so its
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-- Finalization_Size is zero.
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else
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Rewrite (N, Make_Integer_Literal (Loc, 0));
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@ -247,10 +247,10 @@ package Sem_Attr is
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-----------------------
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Attribute_Finalization_Size => True,
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-- For every object, Finalization_Size will return the size of the
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-- internal header required for finalization (including padding). If
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-- the type is not controlled or contains no controlled components
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-- then the result is always zero.
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-- For every object, Finalization_Size returns the size of the hidden
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-- header used for finalization purposes as if the object was allocated
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-- on the heap. The size of the header does take into account any extra
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-- padding due to alignment issues.
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-----------------
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-- Fixed_Value --
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@ -347,7 +347,11 @@ package body Sem_Eval is
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-- Here we have a static predicate (note that it could have arisen from
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-- an explicitly specified Dynamic_Predicate whose expression met the
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-- rules for being predicate-static).
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-- rules for being predicate-static). If the expression is known at
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-- compile time and obeys the predicate, then it is static and must be
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-- labeled as such, which matters e.g. for case statements. The original
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-- expression may be a type conversion of a variable with a known value,
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-- which might otherwise not be marked static.
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-- Case of real static predicate
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@ -356,6 +360,7 @@ package body Sem_Eval is
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(Val => Make_Real_Literal (Sloc (Expr), Expr_Value_R (Expr)),
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Typ => Typ)
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then
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Set_Is_Static_Expression (Expr);
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return;
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end if;
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@ -365,6 +370,7 @@ package body Sem_Eval is
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if Real_Or_String_Static_Predicate_Matches
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(Val => Expr_Value_S (Expr), Typ => Typ)
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then
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Set_Is_Static_Expression (Expr);
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return;
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end if;
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@ -376,6 +382,7 @@ package body Sem_Eval is
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-- If static predicate matches, nothing to do
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if Choices_Match (Expr, Static_Discrete_Predicate (Typ)) = Match then
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Set_Is_Static_Expression (Expr);
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return;
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end if;
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end if;
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