X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=blobdiff_plain;f=libgcc%2Fconfig%2Fi386%2Fmorestack.S;h=9528431f7e67d1647f6d60b25620f26a5b20843e;hp=62f7ce1c0f7f58ccff5666bdf6b2198d03ef86c8;hb=431d4e10e6f2a31b9beb0b572140495cc5e74f35;hpb=d68bb4d5f0b91523ac545d3106327a53b30eaefe

diff --git a/libgcc/config/i386/morestack.S b/libgcc/config/i386/morestack.S
index 62f7ce1c0f7..9528431f7e6 100644
--- a/libgcc/config/i386/morestack.S
+++ b/libgcc/config/i386/morestack.S
@@ -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.
@@ -83,6 +83,9 @@
 #endif
 
 
+# The amount of space we ask for when calling non-split-stack code.
+#define NON_SPLIT_STACK 0x100000
+
 # This entry point is for split-stack code which calls non-split-stack
 # code.  When the linker sees this case, it converts the call to
 # __morestack to call __morestack_non_split instead.  We just bump the
@@ -109,7 +112,7 @@ __morestack_non_split:
 
 	movl	%esp,%eax		# Current stack,
 	subl	8(%esp),%eax		# less required stack frame size,
-	subl	$0x4000,%eax		# less space for non-split code.
+	subl	$NON_SPLIT_STACK,%eax	# less space for non-split code.
 	cmpl	%gs:0x30,%eax		# See if we have enough space.
 	jb	2f			# Get more space if we need it.
 
@@ -138,6 +141,24 @@ __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.
@@ -153,7 +174,8 @@ __morestack_non_split:
 
 	.cfi_adjust_cfa_offset -4	# Account for popped register.
 
-	addl	$0x5000+BACKOFF,4(%esp)	# Increment space we request.
+	# Increment space we request.
+	addl	$NON_SPLIT_STACK+0x1000+BACKOFF,4(%esp)
 
 	# Fall through into morestack.
 
@@ -168,26 +190,41 @@ __morestack_non_split:
 
 	movq	%rsp,%rax		# Current stack,
 	subq	%r10,%rax		# less required stack frame size,
-	subq	$0x4000,%rax		# less space for non-split code.
+	subq	$NON_SPLIT_STACK,%rax	# less space for non-split code.
 
 #ifdef __LP64__
 	cmpq	%fs:0x70,%rax		# See if we have enough space.
 #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:
-	addq	$0x5000+BACKOFF,%r10	# Increment space we request.
+	popq	%rax			# Restore register.
+
+	.cfi_adjust_cfa_offset -8	# Adjust for popped register.
+
+	# Increment space we request.
+	addq	$NON_SPLIT_STACK+0x1000+BACKOFF,%r10
 
 	# Fall through into morestack.