[Bug c/48797] New: GCC does inline variadic function, crashing on i386, when non-GNU stdarg.h is used

[wkor97gy0eef1fr at i dot mintemail.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48797

           Summary: GCC does inline variadic function, crashing on i386,
                    when non-GNU stdarg.h is used
           Product: gcc
           Version: 4.4.5
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: wkor97gy0eef1fr@i.mintemail.com


#include <stdarg.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

static const char* errmsg(int e, const char *em) {
         if (e == ENOENT || e == ENOTDIR) {
                 return em;
         }
         return strerror(e);
}

void ash_vmsg(const char* msg, va_list ap) {
        vfprintf(stderr, msg, ap);
}

void ash_vmsg_and_raise(const char* msg, ...) {
        va_list ap;
        va_start(ap, msg);
        ash_vmsg(msg, ap);
        va_end(ap);
}

int main(int argc, char** argv) {
        int e = argc == 1000 ? 1 : ENOENT;
        ash_vmsg_and_raise("%s: %s", argv[0], errmsg(e, "not found"));
        return 0;
}


when above is compiled with -O3 using a NON-GNU libc (here musl 0.7.9 is used,
where stdarg.h doesnt do some GNU_MAGIC), gcc will inline the errmsg call
inside the variadic function and thus segfault. but only on i386 arch.

clearly it should never inline a variadic function...


Program received signal SIGSEGV, Segmentation fault.
0x08049a5d in memchr ()
(gdb) bt
#0  0x08049a5d in memchr ()  
#1  0x0804964c in printf_core ()
#2  0x0804995d in vfprintf ()
#3  0x080481c7 in ash_vmsg (argc=1, argv=0xbffff834) at test2.c:14
#4  ash_vmsg_and_raise (argc=1, argv=0xbffff834) at test2.c:20
#5  main (argc=1, argv=0xbffff834) at test2.c:26

(gdb) disas ash_vmsg
Dump of assembler code for function ash_vmsg:
0x08048130 <ash_vmsg+0>:        push   %ebp
0x08048131 <ash_vmsg+1>:        mov    %esp,%ebp
0x08048133 <ash_vmsg+3>:        sub    $0x18,%esp
0x08048136 <ash_vmsg+6>:        mov    0xc(%ebp),%eax
0x08048139 <ash_vmsg+9>:        mov    %eax,0x8(%esp)
0x0804813d <ash_vmsg+13>:       mov    0x8(%ebp),%eax
0x08048140 <ash_vmsg+16>:       mov    %eax,0x4(%esp)
0x08048144 <ash_vmsg+20>:       mov    0x804ac54,%eax
0x08048149 <ash_vmsg+25>:       mov    %eax,(%esp)
0x0804814c <ash_vmsg+28>:       call   0x80498c6 <vfprintf>
0x08048151 <ash_vmsg+33>:       leave
0x08048152 <ash_vmsg+34>:       ret
End of assembler dump.
(gdb) disas ash_vmsg_and_raise
Dump of assembler code for function ash_vmsg_and_raise:
0x08048160 <ash_vmsg_and_raise+0>:      push   %ebp
0x08048161 <ash_vmsg_and_raise+1>:      mov    %esp,%ebp
0x08048163 <ash_vmsg_and_raise+3>:      sub    $0x18,%esp
0x08048166 <ash_vmsg_and_raise+6>:      lea    0xc(%ebp),%eax
0x08048169 <ash_vmsg_and_raise+9>:      mov    %eax,0x8(%esp)
0x0804816d <ash_vmsg_and_raise+13>:     mov    0x8(%ebp),%eax
0x08048170 <ash_vmsg_and_raise+16>:     mov    %eax,0x4(%esp)
0x08048174 <ash_vmsg_and_raise+20>:     mov    0x804ac54,%eax
0x08048179 <ash_vmsg_and_raise+25>:     mov    %eax,(%esp)
0x0804817c <ash_vmsg_and_raise+28>:     call   0x80498c6 <vfprintf>
0x08048181 <ash_vmsg_and_raise+33>:     leave
0x08048182 <ash_vmsg_and_raise+34>:     ret
End of assembler dump.
(gdb) disas errmsg
No function contains specified address.
(gdb) disas main
Dump of assembler code for function main:
0x08048190 <main+0>:    push   %ebp
0x08048191 <main+1>:    mov    %esp,%ebp
0x08048193 <main+3>:    and    $0xfffffff0,%esp
0x08048196 <main+6>:    sub    $0x20,%esp
0x08048199 <main+9>:    cmpl   $0x3e8,0x8(%ebp)
0x080481a0 <main+16>:   je     0x80481d0 <main+64>
0x080481a2 <main+18>:   lea    0x20(%esp),%eax
0x080481a6 <main+22>:   mov    %eax,0x8(%esp)
0x080481aa <main+26>:   mov    0x804ac54,%eax
0x080481af <main+31>:   movl   $0x804a4a8,0x1c(%esp)
0x080481b7 <main+39>:   movl   $0x804a4a8,0x4(%esp)
0x080481bf <main+47>:   mov    %eax,(%esp)
0x080481c2 <main+50>:   call   0x80498c6 <vfprintf>
0x080481c7 <main+55>:   xor    %eax,%eax
0x080481c9 <main+57>:   leave
0x080481ca <main+58>:   ret
0x080481cb <main+59>:   nop
0x080481cc <main+60>:   lea    0x0(%esi,%eiz,1),%esi
0x080481d0 <main+64>:   movl   $0x1,(%esp)
0x080481d7 <main+71>:   call   0x804824c <strerror>
0x080481dc <main+76>:   lea    0x0(%esi,%eiz,1),%esi
0x080481e0 <main+80>:   jmp    0x80481a2 <main+18>