From edfef3bd27d6269d473fbc570e8c2be02b4070df Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Thu, 9 May 2013 20:10:38 +0000 Subject: Generate a compact unwind encoding in the face of a stack alignment push. We generate a `push' of a random register (%rax) if the stack needs to be aligned by the size of that register. However, this could mess up compact unwind generation. In particular, we want to still generate compact unwind in the presence of this monstrosity. Check if the push of of the %rax/%eax register. If it is and it's marked with the `FrameSetup' flag, then we can generate a compact unwind encoding for the function only if the push is the last FrameSetup instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181540 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86FrameLowering.cpp | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'lib/Target') diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp index ae51178f73..42b4e73509 100644 --- a/lib/Target/X86/X86FrameLowering.cpp +++ b/lib/Target/X86/X86FrameLowering.cpp @@ -525,6 +525,12 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { // If there are too many saved registers, we cannot use compact encoding. if (SavedRegIdx >= CU_NUM_SAVED_REGS) return CU::UNWIND_MODE_DWARF; + unsigned Reg = MI.getOperand(0).getReg(); + if (Reg == (Is64Bit ? X86::RAX : X86::EAX)) { + ExpectEnd = true; + continue; + } + SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg(); StackAdjust += OffsetSize; InstrOffset += PushInstrSize; -- cgit v1.2.3-18-g5258