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morestack.S (__morestack_non_split): Check whether caller is varargs and needs %bp to hold the stack frame on return. 

libgcc/:
	* config/i386/morestack.S (__morestack_non_split): Check whether
	caller is varargs and needs %bp to hold the stack frame on return.
gcc/testsuite/:
	* gcc.dg/split-6.c: New test.

From-SVN: r187895
This commit is contained in:
Ian Lance Taylor 2012-05-25 20:49:17 +00:00
parent e81a1314e7
commit a2f96eb49d
4 changed files with 102 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2012-05-25 Ian Lance Taylor <iant@google.com>
* gcc.dg/split-6.c: New test.
2012-05-25 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/lto14.adb: New test.

53
gcc/testsuite/gcc.dg/split-6.c Normal file
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@ -0,0 +1,53 @@
/* { dg-do run } */
/* { dg-require-effective-target split_stack } */
/* { dg-options "-fsplit-stack" } */
/* This test is like split-3.c, but tests with a smaller stack frame,
since that uses a different prologue. */
#include <stdarg.h>
#include <stdlib.h>
/* Use a noinline function to ensure that the buffer is not removed
from the stack. */
static void use_buffer (char *buf) __attribute__ ((noinline));
static void
use_buffer (char *buf)
{
buf[0] = '\0';
}
/* When using gold, the call to abort will force a stack split. */
static void
down (int i, ...)
{
char buf[1];
va_list ap;
va_start (ap, i);
if (va_arg (ap, int) != 1
|| va_arg (ap, int) != 2
|| va_arg (ap, int) != 3
|| va_arg (ap, int) != 4
|| va_arg (ap, int) != 5
|| va_arg (ap, int) != 6
|| va_arg (ap, int) != 7
|| va_arg (ap, int) != 8
|| va_arg (ap, int) != 9
|| va_arg (ap, int) != 10)
abort ();
if (i > 0)
{
use_buffer (buf);
down (i - 1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
}
}
int
main (void)
{
down (1000, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
return 0;
}

11
libgcc/ChangeLog
View File

@ -1,3 +1,8 @@
2012-05-25 Ian Lance Taylor <iant@google.com>
* config/i386/morestack.S (__morestack_non_split): Check whether
caller is varargs and needs %bp to hold the stack frame on return.
2012-05-24 Olivier Hainque <hainque@adacore.com>
* Makefile.in: Move dependency on install-unwind_h from
@ -29,9 +34,9 @@
2012-04-28 Aurelien Jarno <aurelien@aurel32.net>
* config.host (mips64*-*-linux*, mipsisa64*-*-linux*): Remove.
(mips*-*-linux*): Include mips/t-tpbit when long double is
16 bytes long.
* config.host (mips64*-*-linux*, mipsisa64*-*-linux*): Remove.
(mips*-*-linux*): Include mips/t-tpbit when long double is
16 bytes long.
2012-04-20 Thomas Schwinge <thomas@codesourcery.com>

42
libgcc/config/i386/morestack.S
View File

@ -1,5 +1,5 @@
# x86/x86_64 support for -fsplit-stack.
# Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.
# Copyright (C) 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
# Contributed by Ian Lance Taylor <iant@google.com>.
# This file is part of GCC.
@ -138,6 +138,24 @@ __morestack_non_split:
je 1f # see above.
addl $2,%eax
1: inc %eax
# If the instruction that we return to is
# leal 20(%ebp),{%eax,%ecx,%edx}
# then we have been called by a varargs function that expects
# %ebp to hold a real value. That can only work if we do the
# full stack split routine. FIXME: This is fragile.
cmpb $0x8d,(%eax)
jne 3f
cmpb $0x14,2(%eax)
jne 3f
cmpb $0x45,1(%eax)
je 2f
cmpb $0x4d,1(%eax)
je 2f
cmpb $0x55,1(%eax)
je 2f
3:
movl %eax,4(%esp) # Update return address.
popl %eax # Restore %eax and stack.
@ -175,18 +193,32 @@ __morestack_non_split:
#else
cmpl %fs:0x40,%eax
#endif
popq %rax # Restore register.
.cfi_adjust_cfa_offset -8 # Adjust for popped register.
jb 2f # Get more space if we need it.
# This breaks call/return prediction, as described above.
incq (%rsp) # Increment the return address.
incq 8(%rsp) # Increment the return address.
# If the instruction that we return to is
# leaq 24(%rbp), %r11n
# then we have been called by a varargs function that expects
# %ebp to hold a real value. That can only work if we do the
# full stack split routine. FIXME: This is fragile.
movq 8(%rsp),%rax
cmpl $0x185d8d4c,(%rax)
je 2f
popq %rax # Restore register.
.cfi_adjust_cfa_offset -8 # Adjust for popped register.
ret # Return to caller.
2:
popq %rax # Restore register.
.cfi_adjust_cfa_offset -8 # Adjust for popped register.
addq $0x5000+BACKOFF,%r10 # Increment space we request.
# Fall through into morestack.