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| author | Reid Kleckner <rnk@google.com> | 2016-02-17 00:17:33 +0000 |
|---|---|---|
| committer | Reid Kleckner <rnk@google.com> | 2016-02-17 00:17:33 +0000 |
| commit | 8de35fef3d2778e7ff6359d237973628c04f279f (patch) | |
| tree | 75fd914466ef17fb627d7d3647f97e69408fe378 /llvm/lib/Target/X86/X86FrameLowering.cpp | |
| parent | b83bedd8c28a8b0c45da05cf9709cdebdd98a2fc (diff) | |
| download | bcm5719-llvm-8de35fef3d2778e7ff6359d237973628c04f279f.tar.gz bcm5719-llvm-8de35fef3d2778e7ff6359d237973628c04f279f.zip | |
[X86] Fix a shrink-wrapping miscompile around __chkstk
__chkstk clobbers EAX. If EAX is live across the prologue, then we have
to take extra steps to save it. We already had code to do this if EAX
was a register parameter. This change adapts it to work when shrink
wrapping is used.
llvm-svn: 261039
Diffstat (limited to 'llvm/lib/Target/X86/X86FrameLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86FrameLowering.cpp | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp index 6e4865475aa..252c81a4bb2 100644 --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -192,10 +192,9 @@ static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB, return 0; } -static bool isEAXLiveIn(MachineFunction &MF) { - for (MachineRegisterInfo::livein_iterator II = MF.getRegInfo().livein_begin(), - EE = MF.getRegInfo().livein_end(); II != EE; ++II) { - unsigned Reg = II->first; +static bool isEAXLiveIn(MachineBasicBlock &MBB) { + for (MachineBasicBlock::RegisterMaskPair RegMask : MBB.liveins()) { + unsigned Reg = RegMask.PhysReg; if (Reg == X86::RAX || Reg == X86::EAX || Reg == X86::AX || Reg == X86::AH || Reg == X86::AL) @@ -261,7 +260,7 @@ void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB, // load the offset into a register and do one sub/add unsigned Reg = 0; - if (isSub && !isEAXLiveIn(*MBB.getParent())) + if (isSub && !isEAXLiveIn(MBB)) Reg = (unsigned)(Is64Bit ? X86::RAX : X86::EAX); else Reg = findDeadCallerSavedReg(MBB, MBBI, TRI, Is64Bit); @@ -1138,8 +1137,8 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF, if (IsWin64Prologue && !IsFunclet && TRI->needsStackRealignment(MF)) AlignedNumBytes = alignTo(AlignedNumBytes, MaxAlign); if (AlignedNumBytes >= StackProbeSize && UseStackProbe) { - // Check whether EAX is livein for this function. - bool isEAXAlive = isEAXLiveIn(MF); + // Check whether EAX is livein for this block. + bool isEAXAlive = isEAXLiveIn(MBB); if (isEAXAlive) { // Sanity check that EAX is not livein for this function. |
