[Bug bootstrap/40027] [4.4/4.5 regression] i686-pc-solaris2.10 bootstrap fails using Sun ld

["hjl dot tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from hjl dot tools at gmail dot com  2009-05-06 14:51 -------
(In reply to comment #1)
> I've just confirmed the bug on i686-pc-solaris2.10.  It doesn't occur on
> i686-pc-solaris2.11, though, so this is indeed a Sun ld bug.
> 
> I've got a few questions to resolve, though:
> 
> * Why does generating code for i686 instead of i386 change gcc's assembler
> output
>   so significantly?
> 

The difference is in how to get PC for -fPIC:

bash-3.2$ cat p.c
void
foo ()
{
  bar ();
}
bash-3.2$ gcc -m32 -fPIC p.c -S -O3 -mtune=i386
bash-3.2$ cat p.s
        .file   "p.c"
        .text
        .p2align 2,,3
.globl foo
        .type   foo, @function
foo:
        pushl   %ebp
        movl    %esp, %ebp
        pushl   %ebx
        subl    $4, %esp
        call    .L3
.L3:
        popl    %ebx
        addl    $_GLOBAL_OFFSET_TABLE_+[.-.L3], %ebx
        call    bar@PLT
        popl    %eax
        popl    %ebx
        leave
        ret
        .size   foo, .-foo
        .ident  "GCC: (GNU) 4.3.2 20081105 (Red Hat 4.3.2-7)"
        .section        .note.GNU-stack,"",@progbits
bash-3.2$ gcc -m32 -fPIC p.c -S -O3 -mtune=i686
bash-3.2$ cat p.s
        .file   "p.c"
        .text
        .p2align 4,,15
.globl foo
        .type   foo, @function
foo:
        pushl   %ebp
        movl    %esp, %ebp
        pushl   %ebx
        call    __i686.get_pc_thunk.bx
        addl    $_GLOBAL_OFFSET_TABLE_, %ebx
        subl    $4, %esp
        call    bar@PLT
        addl    $4, %esp
        popl    %ebx
        popl    %ebp
        ret
        .size   foo, .-foo
        .ident  "GCC: (GNU) 4.3.2 20081105 (Red Hat 4.3.2-7)"
        .section       
.text.__i686.get_pc_thunk.bx,"axG",@progbits,__i686.get_pc_thunk.bx,comdat
.globl __i686.get_pc_thunk.bx
        .hidden __i686.get_pc_thunk.bx
        .type   __i686.get_pc_thunk.bx, @function
__i686.get_pc_thunk.bx:
        movl    (%esp), %ebx
        ret
        .section        .note.GNU-stack,"",@progbits
bash-3.2$ 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40027