------- Comment #2 from jakub at gcc dot gnu dot org 2010-03-08 21:07 -------
On the:
int i;
static int j;
extern int bar (void);
int foo (void)
{
return i + j + bar ();
}
testcase with -fexceptions -O2 -mtune=generic -dA -m32 -fpic the difference is:
@@ -14,9 +14,9 @@ foo:
.cfi_def_cfa_register 5
subl $8, %esp
movl %ebx, (%esp)
+ .cfi_offset 3, -16
call __i686.get_pc_thunk.bx
addl $_GLOBAL_OFFSET_TABLE_, %ebx
- .cfi_offset 3, -16
movl %esi, 4(%esp)
movl i...@got(%ebx), %eax
movl (%eax), %esi
@@ -43,6 +43,8 @@ foo:
.hidden __i686.get_pc_thunk.bx
.type __i686.get_pc_thunk.bx, @function
__i686.get_pc_thunk.bx:
+ .cfi_startproc
movl (%esp), %ebx
ret
+ .cfi_endproc
.section .note.GNU-stack,"",@progbits
and with -fexceptions -O2 -mtune=i586 -dA -m32 -fpic -fomit-frame-pointer the
difference is:@@ -14,11 +14,13 @@ foo:
subl $4, %esp
.cfi_def_cfa_offset 16
call .L2
+ .cfi_def_cfa_offset 20
.L2:
popl %ebx
- addl $_GLOBAL_OFFSET_TABLE_+[.-.L2], %ebx
.cfi_offset 3, -12
.cfi_offset 6, -8
+ .cfi_def_cfa_offset 16
+ addl $_GLOBAL_OFFSET_TABLE_+[.-.L2], %ebx
movl i...@got(%ebx), %eax
movl (%eax), %esi
call b...@plt
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43293
