[llvm-commits] [llvm-gcc-4.2] r50402 - /llvm-gcc-4.2/trunk/gcc/config/i386/cygwin.asm
Anton Korobeynikov
asl at math.spbu.ru
Mon Apr 28 23:22:10 PDT 2008
Author: asl
Date: Tue Apr 29 01:22:09 2008
New Revision: 50402
URL: http://llvm.org/viewvc/llvm-project?rev=50402&view=rev
Log:
Backport from mainline.
Provide win64 version of __alloca()
Modified:
llvm-gcc-4.2/trunk/gcc/config/i386/cygwin.asm
Modified: llvm-gcc-4.2/trunk/gcc/config/i386/cygwin.asm
URL: http://llvm.org/viewvc/llvm-project/llvm-gcc-4.2/trunk/gcc/config/i386/cygwin.asm?rev=50402&r1=50401&r2=50402&view=diff
==============================================================================
--- llvm-gcc-4.2/trunk/gcc/config/i386/cygwin.asm (original)
+++ llvm-gcc-4.2/trunk/gcc/config/i386/cygwin.asm Tue Apr 29 01:22:09 2008
@@ -42,27 +42,97 @@
.global ___chkstk
.global __alloca
+/* LLVM LOCAL begin mainline */
+#ifndef _WIN64
___chkstk:
__alloca:
- pushl %ecx /* save temp */
- movl %esp,%ecx /* get sp */
- addl $0x8,%ecx /* and point to return addr */
-
-probe: cmpl $0x1000,%eax /* > 4k ?*/
- jb done
-
- subl $0x1000,%ecx /* yes, move pointer down 4k*/
- orl $0x0,(%ecx) /* probe there */
- subl $0x1000,%eax /* decrement count */
- jmp probe /* and do it again */
-
-done: subl %eax,%ecx
- orl $0x0,(%ecx) /* less that 4k, just peek here */
-
- movl %esp,%eax
- movl %ecx,%esp /* decrement stack */
-
- movl (%eax),%ecx /* recover saved temp */
- movl 4(%eax),%eax /* get return address */
- jmp *%eax
+ pushl %ecx /* save temp */
+ leal 8(%esp), %ecx /* point past return addr */
+ cmpl $0x1000, %eax /* > 4k ?*/
+ jb Ldone
+
+Lprobe:
+ subl $0x1000, %ecx /* yes, move pointer down 4k*/
+ orl $0x0, (%ecx) /* probe there */
+ subl $0x1000, %eax /* decrement count */
+ cmpl $0x1000, %eax
+ ja Lprobe /* and do it again */
+
+Ldone:
+ subl %eax, %ecx
+ orl $0x0, (%ecx) /* less than 4k, just peek here */
+
+ movl %esp, %eax /* save old stack pointer */
+ movl %ecx, %esp /* decrement stack */
+ movl (%eax), %ecx /* recover saved temp */
+ movl 4(%eax), %eax /* recover return address */
+
+ /* Push the return value back. Doing this instead of just
+ jumping to %eax preserves the cached call-return stack
+ used by most modern processors. */
+ pushl %eax
+ ret
+#else
+/* __alloca is a normal function call, which uses %rcx as the argument. And stack space
+ for the argument is saved. */
+__alloca:
+ movq %rcx, %rax
+ addq $0x7, %rax
+ andq $0xfffffffffffffff8, %rax
+ popq %rcx /* pop return address */
+ popq %r10 /* Pop the reserved stack space. */
+ movq %rsp, %r10 /* get sp */
+ cmpq $0x1000, %rax /* > 4k ?*/
+ jb Ldone_alloca
+
+Lprobe_alloca:
+ subq $0x1000, %r10 /* yes, move pointer down 4k*/
+ orq $0x0, (%r10) /* probe there */
+ subq $0x1000, %rax /* decrement count */
+ cmpq $0x1000, %rax
+ ja Lprobe_alloca /* and do it again */
+
+Ldone_alloca:
+ subq %rax, %r10
+ orq $0x0, (%r10) /* less than 4k, just peek here */
+ movq %r10, %rax
+ subq $0x8, %r10 /* Reserve argument stack space. */
+ movq %r10, %rsp /* decrement stack */
+
+ /* Push the return value back. Doing this instead of just
+ jumping to %rcx preserves the cached call-return stack
+ used by most modern processors. */
+ pushq %rcx
+ ret
+
+/* ___chkstk is a *special* function call, which uses %rax as the argument.
+ We avoid clobbering the 4 integer argument registers, %rcx, %rdx,
+ %r8 and %r9, which leaves us with %rax, %r10, and %r11 to use. */
+___chkstk:
+ addq $0x7, %rax /* Make sure stack is on alignment of 8. */
+ andq $0xfffffffffffffff8, %rax
+ popq %r11 /* pop return address */
+ movq %rsp, %r10 /* get sp */
+ cmpq $0x1000, %rax /* > 4k ?*/
+ jb Ldone
+
+Lprobe:
+ subq $0x1000, %r10 /* yes, move pointer down 4k*/
+ orl $0x0, (%r10) /* probe there */
+ subq $0x1000, %rax /* decrement count */
+ cmpq $0x1000, %rax
+ ja Lprobe /* and do it again */
+
+Ldone:
+ subq %rax, %r10
+ orl $0x0, (%r10) /* less than 4k, just peek here */
+ movq %r10, %rsp /* decrement stack */
+
+ /* Push the return value back. Doing this instead of just
+ jumping to %r11 preserves the cached call-return stack
+ used by most modern processors. */
+ pushq %r11
+ ret
+#endif
+/* LLVM LOCAL end mainline */
#endif
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