This is a regression present on all active branches: under a specific set of
circumstances, the compiler generate wrong code for the assignment of an array
component of a record type, when the nominal subtype of the component is an
array type with an alignment clause that specifies a larger alignment than the
natural one.
Tested on x86_64-suse-linux, applied on all active branches.
2019-01-26 Eric Botcazou <ebotca...@adacore.com>
* gcc-interface/trans.c (gnat_to_gnu) <N_Assignment_Statement>: Use
DECL_SIZE_UNIT instead of TYPE_SIZE_UNIT for the size to be assigned
by a call to memset if the LHS is a DECL.
2019-01-26 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/array34.adb: New test.
--
Eric Botcazou
Index: gcc-interface/trans.c
===================================================================
--- gcc-interface/trans.c (revision 335507)
+++ gcc-interface/trans.c (revision 335508)
@@ -7754,12 +7754,17 @@ gnat_to_gnu (Node_Id gnat_node)
= real_zerop (gnu_rhs)
? integer_zero_node
: fold_convert (integer_type_node, gnu_rhs);
- tree to = gnu_lhs;
- tree type = TREE_TYPE (to);
- tree size
- = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TYPE_SIZE_UNIT (type), to);
- tree to_ptr = build_fold_addr_expr (to);
+ tree dest = build_fold_addr_expr (gnu_lhs);
tree t = builtin_decl_explicit (BUILT_IN_MEMSET);
+ /* Be extra careful not to write too much data. */
+ tree size;
+ if (TREE_CODE (gnu_lhs) == COMPONENT_REF)
+ size = DECL_SIZE_UNIT (TREE_OPERAND (gnu_lhs, 1));
+ else if (DECL_P (gnu_lhs))
+ size = DECL_SIZE_UNIT (gnu_lhs);
+ else
+ size = TYPE_SIZE_UNIT (TREE_TYPE (gnu_lhs));
+ size = SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, gnu_lhs);
if (TREE_CODE (value) == INTEGER_CST && !integer_zerop (value))
{
tree mask
@@ -7767,7 +7772,7 @@ gnat_to_gnu (Node_Id gnat_node)
((HOST_WIDE_INT) 1 << BITS_PER_UNIT) - 1);
value = int_const_binop (BIT_AND_EXPR, value, mask);
}
- gnu_result = build_call_expr (t, 3, to_ptr, value, size);
+ gnu_result = build_call_expr (t, 3, dest, value, size);
}
/* Otherwise build a regular assignment. */
-- { dg-do run }
procedure Array34 is
type Arr is array (1 .. 6) of Short_Short_Integer;
for Arr'Alignment use 4;
type Rec is record
A : Arr;
B: Short_Integer;
end record;
pragma Pack (Rec);
R : Rec;
begin
R.B := 31415;
R.A := (others => 0);
if R.B /= 31415 then
raise Program_Error;
end if;
end;