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linux-user: Fix i386 safe-syscall.S
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Clang insists that "cmp" is ambiguous with a memory destination,
requiring an explicit size suffix.

There was a true error in the use of .cfi_def_cfa_offset in the
epilogue, but changing to use the proper .cfi_adjust_cfa_offset
runs afoul of a clang bug wrt .cfi_restore_state.  Better to
fold the two epilogues so that we don't trigger the bug.

Signed-off-by: Richard Henderson <rth@twiddle.net>
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rth7680 committed Jul 8, 2016
1 parent 4f4a9ca commit 4aa3f4d
Showing 1 changed file with 6 additions and 18 deletions.
24 changes: 6 additions & 18 deletions linux-user/host/i386/safe-syscall.inc.S
Expand Up @@ -69,44 +69,32 @@ safe_syscall_base:
safe_syscall_start:
/* if signal_pending is non-zero, don't do the call */
mov 4+16(%esp), %eax /* signal_pending */
cmp $0, (%eax)
cmpl $0, (%eax)
jnz 1f
mov 8+16(%esp), %eax /* syscall number */
int $0x80
safe_syscall_end:
/* code path for having successfully executed the syscall */
pop %ebx
.cfi_remember_state
.cfi_def_cfa_offset -4
.cfi_adjust_cfa_offset -4
.cfi_restore ebx
pop %edi
.cfi_def_cfa_offset -4
.cfi_adjust_cfa_offset -4
.cfi_restore edi
pop %esi
.cfi_def_cfa_offset -4
.cfi_adjust_cfa_offset -4
.cfi_restore esi
pop %ebp
.cfi_def_cfa_offset -4
.cfi_adjust_cfa_offset -4
.cfi_restore ebp
ret

1:
/* code path when we didn't execute the syscall */
.cfi_restore_state
mov $-TARGET_ERESTARTSYS, %eax
pop %ebx
.cfi_def_cfa_offset -4
.cfi_restore ebx
pop %edi
.cfi_def_cfa_offset -4
.cfi_restore edi
pop %esi
.cfi_def_cfa_offset -4
.cfi_restore esi
pop %ebp
.cfi_def_cfa_offset -4
.cfi_restore ebp
ret
jmp safe_syscall_end
.cfi_endproc

.size safe_syscall_base, .-safe_syscall_base

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