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Fix handling of non-integral bit-fields in native_encode_initializer

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The encoder for CONSTRUCTORs assumes that all bit-fields (DECL_BIT_FIELD)
have integral types, but that's not the case in Ada where they may have
pretty much any type, resulting in a wrong encoding for them

gcc/
	* fold-const.cc (native_encode_initializer) <CONSTRUCTOR>: Apply the
	specific treatment for bit-fields only if they have an integral type
	and filter out non-integral bit-fields that do not start and end on
	a byte boundary.

gcc/testsuite/
	* gnat.dg/opt101.adb: New test.
	* gnat.dg/opt101_pkg.ads: New helper.
This commit is contained in:
Eric Botcazou 2023-05-23 10:15:35 +02:00
parent 77f27066c3
commit 180db383a9
3 changed files with 66 additions and 10 deletions
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27
gcc/fold-const.cc
View File

@ -8428,20 +8428,26 @@ native_encode_initializer (tree init, unsigned char *ptr, int len,
if (fieldsize == 0)
continue;
/* Prepare to deal with integral bit-fields and filter out other
bit-fields that do not start and end on a byte boundary. */
if (DECL_BIT_FIELD (field))
{
if (!tree_fits_uhwi_p (DECL_FIELD_BIT_OFFSET (field)))
return 0;
fieldsize = TYPE_PRECISION (TREE_TYPE (field));
bpos = tree_to_uhwi (DECL_FIELD_BIT_OFFSET (field));
if (bpos % BITS_PER_UNIT)
bpos %= BITS_PER_UNIT;
else
bpos = 0;
fieldsize += bpos;
epos = fieldsize % BITS_PER_UNIT;
fieldsize += BITS_PER_UNIT - 1;
fieldsize /= BITS_PER_UNIT;
if (INTEGRAL_TYPE_P (TREE_TYPE (field)))
{
bpos %= BITS_PER_UNIT;
fieldsize = TYPE_PRECISION (TREE_TYPE (field)) + bpos;
epos = fieldsize % BITS_PER_UNIT;
fieldsize += BITS_PER_UNIT - 1;
fieldsize /= BITS_PER_UNIT;
}
else if (bpos % BITS_PER_UNIT
|| DECL_SIZE (field) == NULL_TREE
|| !tree_fits_shwi_p (DECL_SIZE (field))
|| tree_to_shwi (DECL_SIZE (field)) % BITS_PER_UNIT)
return 0;
}
if (off != -1 && pos + fieldsize <= off)
@ -8450,7 +8456,8 @@ native_encode_initializer (tree init, unsigned char *ptr, int len,
if (val == NULL_TREE)
continue;
if (DECL_BIT_FIELD (field))
if (DECL_BIT_FIELD (field)
&& INTEGRAL_TYPE_P (TREE_TYPE (field)))
{
/* FIXME: Handle PDP endian. */
if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)

23
gcc/testsuite/gnat.dg/opt101.adb Normal file
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@ -0,0 +1,23 @@
-- { dg-do run }
-- { dg-options "-O" }
pragma Optimize_Alignment (Space);
with Opt101_Pkg; use Opt101_Pkg;
procedure Opt101 is
C1 : Cont1;
C2 : Cont2;
begin
C1 := ((1234, 1, 2), 1, 2);
if C1.R.I1 /= 1 or C1.I2 /= 2 then
raise Program_Error;
end if;
C2 := (1, (1234, 1, 2), 2);
if C2.R.I1 /= 1 or C2.I2 /= 2 then
raise Program_Error;
end if;
end;

26
gcc/testsuite/gnat.dg/opt101_pkg.ads Normal file
View File

@ -0,0 +1,26 @@
package Opt101_Pkg is
type Int is mod 16;
type Rec is record
S : Short_Integer;
I1, I2 : Int;
end record;
pragma Pack (Rec);
for Rec'Alignment use 4;
type Cont1 is record
R : Rec;
I1, I2 : Int;
end record;
pragma Pack (Cont1);
type Cont2 is record
I1 : Int;
R : Rec;
I2 : Int;
end record;
pragma Pack (Cont2);
pragma No_Component_Reordering (Cont2);
end Opt101_Pkg;