[Bug target/38902] __builtin_strcpy doesn't work with -fstack-protector

[hjl dot tools at gmail dot com]

------- Comment #4 from hjl dot tools at gmail dot com  2009-01-18 17:05 -------
bash-3.2$ cat /tmp/x.c
extern void abort ();
int foo (const char *, const char *);
void bar (void)
{
  char buffer[1024]="";
  __builtin_strcpy (buffer, "1234567890abcdefghijklmno");
  if (foo (buffer, "1234567890abcdefghijklmno"))
    abort ();
}
bash-3.2$ cat /tmp/y.c
int
foo (const char *x , const char * y)
{
  return __builtin_strcmp (x, y);
}
extern void bar (void);
int
main ()
{
  bar ();
  return 0;
}
bash-3.2$ ./xgcc -B./ -O2 -m32 -O2 -fstack-protector /tmp/x.c -c
bash-3.2$ ./xgcc -B./ -m32 /tmp/y.c -c
bash-3.2$ ./xgcc -B./ -m32 x.o y.o
bash-3.2$ ./a.out 
Aborted
bash-3.2$ ./xgcc -B./ -O2 -m32 -O2 -fstack-protector /tmp/x.c -S
bash-3.2$ cat x.s
        .file   "x.c"
        .section        .rodata.str1.1,"aMS",@progbits,1
.LC0:
        .string "1234567890abcdefghijklmno"
        .text
        .p2align 4,,15
.globl bar
        .type   bar, @function
bar:
        pushl   %ebp
        movl    $255, %ecx
        movl    %esp, %ebp
        pushl   %edi
        subl    $1060, %esp
        movl    %gs:20, %eax
        movl    %eax, -8(%ebp)
        xorl    %eax, %eax
        leal    -1028(%ebp), %edi
        movl    $875770417, -1032(%ebp)
        movl    $1650536505, -1024(%ebp)
        movl    $1717920867, -1020(%ebp)
        movl    $1785292903, -1016(%ebp)
        movl    $1852664939, -1012(%ebp)
        rep stosl <<<<<<< Wrong place
        leal    -1032(%ebp), %eax
        movl    $943142453, -1028(%ebp)
        movw    $111, -1008(%ebp)
        movl    $.LC0, 4(%esp)
        movl    %eax, (%esp)
        call    foo
        testl   %eax, %eax
        jne     .L7
        movl    -8(%ebp), %eax
        xorl    %gs:20, %eax
        jne     .L8
        addl    $1060, %esp
        popl    %edi
        popl    %ebp
        .p2align 4,,3
        .p2align 3
        ret
.L7:
        .p2align 4,,6
        .p2align 3
        call    abort
.L8:
        .p2align 4,,5
        .p2align 3
        call    __stack_chk_fail
        .size   bar, .-bar


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38902