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More closely follow libgcc, which has code after the `ret' instruction to

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release the stack segment and reset the stack pointer. Place the code in its own
MBB to make the verifier happy.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141859 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2011-10-13 08:24:19 +00:00
parent 1203fe7fc8
commit 4e68054b20
2 changed files with 27 additions and 8 deletions
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33
lib/Target/X86/X86FrameLowering.cpp
View File

@ -1336,15 +1336,28 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const {
if (Is64Bit)
IsNested = HasNestArgument(&MF);
// The MOV R10, RAX needs to be in a different block, since the RET we emit in
// allocMBB needs to be last (terminating) instruction.
MachineBasicBlock *restoreR10MBB = NULL;
if (IsNested)
restoreR10MBB = MF.CreateMachineBasicBlock();
for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(),
e = prologueMBB.livein_end(); i != e; i++) {
allocMBB->addLiveIn(*i);
checkMBB->addLiveIn(*i);
if (IsNested)
restoreR10MBB->addLiveIn(*i);
}
if (IsNested) {
allocMBB->addLiveIn(X86::R10);
restoreR10MBB->addLiveIn(X86::RAX);
}
if (IsNested)
allocMBB->addLiveIn(X86::R10);
MF.push_front(restoreR10MBB);
MF.push_front(allocMBB);
MF.push_front(checkMBB);
@ -1414,13 +1427,19 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const {
if (!Is64Bit)
BuildMI(allocMBB, DL, TII.get(X86::ADD32ri), X86::ESP).addReg(X86::ESP)
.addImm(8);
if (Is64Bit && IsNested)
BuildMI(allocMBB, DL, TII.get(X86::MOV64rr), X86::R10).addReg(X86::RAX);
BuildMI(allocMBB, DL, TII.get(X86::RET));
allocMBB->addSuccessor(&prologueMBB);
if (IsNested)
BuildMI(restoreR10MBB, DL, TII.get(X86::MOV64rr), X86::R10)
.addReg(X86::RAX);
if (IsNested) {
allocMBB->addSuccessor(restoreR10MBB);
restoreR10MBB->addSuccessor(&prologueMBB);
} else {
allocMBB->addSuccessor(&prologueMBB);
}
checkMBB->addSuccessor(allocMBB);
checkMBB->addSuccessor(&prologueMBB);

2
test/CodeGen/X86/segmented-stacks.ll
View File

@ -81,7 +81,7 @@ define i32 @test_nested(i32 * nest %closure, i32 %other) {
; X64-NEXT: movabsq $0, %r10
; X64-NEXT: movabsq $0, %r11
; X64-NEXT: callq __morestack
; X64-NEXT: movq %rax, %r10
; X64-NEXT: ret
; X64: movq %rax, %r10
}