[Bug lto/57703] Assembler function definition moved to a different ltrans then call

["marxin.liska at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57703

--- Comment #4 from Martin LiÅka <marxin.liska at gmail dot com> ---
Hm, it looks that there's an usage of top-level function chromium binary:

/tmp/cckAZyDK.ltrans26.ltrans.o:cckAZyDK.ltrans26.o:function
sandbox::Die::ExitGroup(): error: undefined reference to 'SyscallAsm'
/tmp/cckAZyDK.ltrans26.ltrans.o:cckAZyDK.ltrans26.o:function
sandbox::Die::ExitGroup(): error: undefined reference to 'SyscallAsm'
/tmp/cckAZyDK.ltrans26.ltrans.o:cckAZyDK.ltrans26.o:function
sandbox::Die::SandboxDie(char const*, char const*, int): error: undefined
reference to 'SyscallAsm'
/tmp/cckAZyDK.ltrans26.ltrans.o:cckAZyDK.ltrans26.o:function
sandbox::Trap::SigSys(int, siginfo_t*, void*): error: undefined reference to
'SyscallAsm'


SyscallAsm:
namespace playground2 {

  asm volatile(
# 76 "../../sandbox/linux/seccomp-bpf/syscall.cc"
            ".text\n"
            ".align 16, 0x90\n"
            ".type SyscallAsm, @function\n"
 "SyscallAsm:.cfi_startproc\n"




            "test %rax, %rax\n"
            "jge  1f\n"


            "call 0f;   .cfi_adjust_cfa_offset  8\n"
          "0:pop  %rax; .cfi_adjust_cfa_offset -8\n"
            "addq $2f-0b, %rax\n"
            "ret\n"




          "1:movq  0(%r12), %rdi\n"
            "movq  8(%r12), %rsi\n"
            "movq 16(%r12), %rdx\n"
            "movq 24(%r12), %r10\n"
            "movq 32(%r12), %r8\n"
            "movq 40(%r12), %r9\n"

            "syscall\n"

          "2:ret\n"
            ".cfi_endproc\n"
          "9:.size SyscallAsm, 9b-SyscallAsm\n"
# 172 "../../sandbox/linux/seccomp-bpf/syscall.cc"
  );

If it's not supported feature, how could we handle such situation in LTO?
Assembler functions are commong in all kind video/audio codecs which are often
added to firefox/chromium.

Martin