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Fix a bug in the x86-32 code generated for segmented stacks.

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Currently LLVM pads the call to __morestack with a add and sub of 8
bytes to esp.  This isn't correct since __morestack expects the call
to be followed directly by a ret.

This commit also adjusts the relevant test-case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145765 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjoy Das 2011-12-03 09:21:07 +00:00
parent 3604924799
commit 40f8222e1e
2 changed files with 2 additions and 14 deletions
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8
lib/Target/X86/X86FrameLowering.cpp
View File

@ -1394,9 +1394,6 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const {
MF.getRegInfo().setPhysRegUsed(X86::R10);
MF.getRegInfo().setPhysRegUsed(X86::R11);
} else {
// Since we'll call __morestack, stack alignment needs to be preserved.
BuildMI(allocMBB, DL, TII.get(X86::SUB32ri), X86::ESP).addReg(X86::ESP)
.addImm(8);
BuildMI(allocMBB, DL, TII.get(X86::PUSHi32))
.addImm(X86FI->getArgumentStackSize());
BuildMI(allocMBB, DL, TII.get(X86::PUSHi32))
@ -1411,11 +1408,6 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const {
BuildMI(allocMBB, DL, TII.get(X86::CALLpcrel32))
.addExternalSymbol("__morestack");
// __morestack only seems to remove 8 bytes off the stack. Add back the
// additional 8 bytes we added before pushing the arguments.
if (!Is64Bit)
BuildMI(allocMBB, DL, TII.get(X86::ADD32ri), X86::ESP).addReg(X86::ESP)
.addImm(8);
if (IsNested)
BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET_RESTORE_R10));
else

8
test/CodeGen/X86/segmented-stacks.ll
View File

@ -23,11 +23,9 @@ false:
; X32: leal -12(%esp), %ecx
; X32-NEXT: cmpl %gs:48, %ecx
; X32: subl $8, %esp
; X32-NEXT: pushl $4
; X32: pushl $4
; X32-NEXT: pushl $12
; X32-NEXT: calll __morestack
; X32-NEXT: addl $8, %esp
; X32-NEXT: ret
; X32: movl %esp, %eax
@ -72,11 +70,9 @@ define i32 @test_nested(i32 * nest %closure, i32 %other) {
; X32-NEXT: cmpl %gs:48, %edx
; X32: subl $8, %esp
; X32-NEXT: pushl $4
; X32: pushl $4
; X32-NEXT: pushl $0
; X32-NEXT: calll __morestack
; X32-NEXT: addl $8, %esp
; X32-NEXT: ret
; X64: leaq (%rsp), %r11