[llvm] r179808 - Set the compact unwind encoding to 'requires EH DWARF' if we cannot generate a CU encoding.

[Eric Christopher]

Testcase? ;)

-eric

On Thu, Apr 18, 2013 at 3:55 PM, Bill Wendling <isanbard at gmail.com> wrote:
> Author: void
> Date: Thu Apr 18 17:55:29 2013
> New Revision: 179808
>
> URL: http://llvm.org/viewvc/llvm-project?rev=179808&view=rev
> Log:
> Set the compact unwind encoding to 'requires EH DWARF' if we cannot generate a CU encoding.
>
> Modified:
>     llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
>
> Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=179808&r1=179807&r2=179808&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Thu Apr 18 17:55:29 2013
> @@ -528,11 +528,11 @@ uint32_t X86FrameLowering::getCompactUnw
>      if (!MI.getFlag(MachineInstr::FrameSetup)) break;
>
>      // We don't exect any more prolog instructions.
> -    if (ExpectEnd) return 0;
> +    if (ExpectEnd) return 0x04000000;
>
>      if (Opc == PushInstr) {
>        // If there are too many saved registers, we cannot use compact encoding.
> -      if (SavedRegIdx >= CU_NUM_SAVED_REGS) return 0;
> +      if (SavedRegIdx >= CU_NUM_SAVED_REGS) return 0x04000000;
>
>        SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg();
>        StackAdjust += OffsetSize;
> @@ -542,7 +542,7 @@ uint32_t X86FrameLowering::getCompactUnw
>        unsigned DstReg = MI.getOperand(0).getReg();
>
>        if (DstReg != FramePtr || SrcReg != StackPtr)
> -        return 0;
> +        return 0x04000000;
>
>        StackAdjust = 0;
>        memset(SavedRegs, 0, sizeof(SavedRegs));
> @@ -552,7 +552,7 @@ uint32_t X86FrameLowering::getCompactUnw
>                 Opc == X86::SUB32ri || Opc == X86::SUB32ri8) {
>        if (StackSize)
>          // We already have a stack size.
> -        return 0;
> +        return 0x04000000;
>
>        if (!MI.getOperand(0).isReg() ||
>            MI.getOperand(0).getReg() != MI.getOperand(1).getReg() ||
> @@ -560,7 +560,7 @@ uint32_t X86FrameLowering::getCompactUnw
>          // We need this to be a stack adjustment pointer. Something like:
>          //
>          //   %RSP<def> = SUB64ri8 %RSP, 48
> -        return 0;
> +        return 0x04000000;
>
>        StackSize = MI.getOperand(2).getImm() / StackDivide;
>        SubtractInstrIdx += InstrOffset;
> @@ -574,11 +574,11 @@ uint32_t X86FrameLowering::getCompactUnw
>    if (HasFP) {
>      if ((StackAdjust & 0xFF) != StackAdjust)
>        // Offset was too big for compact encoding.
> -      return 0;
> +      return 0x04000000;
>
>      // Get the encoding of the saved registers when we have a frame pointer.
>      uint32_t RegEnc = encodeCompactUnwindRegistersWithFrame(SavedRegs, Is64Bit);
> -    if (RegEnc == ~0U) return 0;
> +    if (RegEnc == ~0U) return 0x04000000;
>
>      CompactUnwindEncoding |= 0x01000000;
>      CompactUnwindEncoding |= (StackAdjust & 0xFF) << 16;
> @@ -595,7 +595,7 @@ uint32_t X86FrameLowering::getCompactUnw
>      } else {
>        if ((StackAdjust & 0x7) != StackAdjust)
>          // The extra stack adjustments are too big for us to handle.
> -        return 0;
> +        return 0x04000000;
>
>        // Frameless stack with an offset too large for us to encode compactly.
>        CompactUnwindEncoding |= 0x03000000;
> @@ -616,7 +616,7 @@ uint32_t X86FrameLowering::getCompactUnw
>      uint32_t RegEnc =
>        encodeCompactUnwindRegistersWithoutFrame(SavedRegs, SavedRegIdx,
>                                                 Is64Bit);
> -    if (RegEnc == ~0U) return 0;
> +    if (RegEnc == ~0U) return 0x04000000;
>
>      // Encode the register encoding.
>      CompactUnwindEncoding |= RegEnc & 0x3FF;
>
>
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