Hi,
this patch fixes old regression about ms-bitfields structure layout.
This patch was
verified by VLC community and libAV people (as to see in bug-report).
The result of
the structure-layout was also compared to VC's 32-bit and 64-bit
result by VLC people.
ChangeLog
2012-02-17 Kai Tietz <kti...@redhat.com>
PR target/52238
* stor-layout.c (place_field): Handle desired_align for
ms-bitfields, too.
2012-02-17 Kai Tietz <kti...@redhat.com>
* gcc.dg/bf-ms-layout-3.c: New testcase.
Tested for i686-w64-mingw32, x86_64-w64-mingw32, i686-pc-cygwin. Ok for apply?
Regards,
Kai
Index: gcc/gcc/stor-layout.c
===================================================================
--- gcc.orig/gcc/stor-layout.c
+++ gcc/gcc/stor-layout.c
@@ -1141,15 +1141,14 @@ place_field (record_layout_info rli, tre
}
/* Does this field automatically have alignment it needs by virtue
- of the fields that precede it and the record's own alignment?
- We already align ms_struct fields, so don't re-align them. */
- if (known_align < desired_align
- && !targetm.ms_bitfield_layout_p (rli->t))
+ of the fields that precede it and the record's own alignment? */
+ if (known_align < desired_align)
{
/* No, we need to skip space before this field.
Bump the cumulative size to multiple of field alignment. */
- if (DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION)
+ if (!targetm.ms_bitfield_layout_p (rli->t)
+ && DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION)
warning (OPT_Wpadded, "padding struct to align %q+D", field);
/* If the alignment is still within offset_align, just align
@@ -1171,7 +1170,8 @@ place_field (record_layout_info rli, tre
if (! TREE_CONSTANT (rli->offset))
rli->offset_align = desired_align;
-
+ if (targetm.ms_bitfield_layout_p (rli->t))
+ rli->prev_field = NULL;
}
/* Handle compatibility with PCC. Note that if the record has any
Index: gcc/gcc/testsuite/gcc.dg/bf-ms-layout-3.c
===================================================================
--- /dev/null
+++ gcc/gcc/testsuite/gcc.dg/bf-ms-layout-3.c
@@ -0,0 +1,47 @@
+/* Test for MS bitfield layout */
+/* { dg-do run { target *-*-interix* *-*-mingw* *-*-cygwin*
i?86-*-darwin* } } */
+/* { dg-options "-mms-bitfields" } */
+
+extern void abort();
+
+struct {
+ char a;
+ char b __attribute__ ((aligned (16)));
+} s1;
+
+struct {
+ char a;
+ char b;
+} s2;
+
+struct {
+ char a : 6;
+ char b __attribute__ ((aligned (16)));
+} s3;
+
+struct {
+ char a : 6;
+ char b __attribute__ ((aligned (2)));
+} s4;
+
+struct {
+ char a : 6;
+ char b __attribute__ ((aligned (1)));
+} s5;
+
+__PTRDIFF_TYPE__ offs (const void *a, const void *b)
+{
+ return (__PTRDIFF_TYPE__) ((const char*)a - (const char*)b);
+}
+
+int main()
+{
+ if (offs (&s1.b, &s1) != 16
+ || offs (&s2.b, &s2) != 1
+ || offs (&s3.b, &s3) != 16
+ || offs (&s4.b, &s4) != 2
+ || offs (&s5.b, &s5) != 1)
+ abort ();
+ return 0;
+}
+
