[llvm-commits] [llvm] r137830 - in /llvm/trunk: include/llvm/MC/ lib/Target/ARM/Disassembler/ lib/Target/MBlaze/Disassembler/ lib/Target/X86/Disassembler/ test/MC/Disassembler/ARM/ tools/llvm-mc/ utils/TableGen/

James Molloy james.molloy at arm.com
Wed Aug 31 04:07:19 PDT 2011


Hi Jim,

Apologies, somehow my spam filter got ahold of both of your replies. Lucky I
checked it so soon after your ping, really :(

Changing to switch() in Disassembler.cpp, need to change in MCDisassembler and
EDDisassembler
--------------------------------------------------------------------------------
-------------

I will do.

Fail -> llvm::MCDisassembler::Fail
----------------------------------

Can do; now that I've done the grunt work a simple regex will suffice to do
that. I'd suggest "using namespace llvm;" though to shorten it slightly - are
you OK with that?

No early exit
-------------

I can remove this. I thought it made the code flow easier, but I see your point
that hiding the early exit is inadvisable.

Use enum values instead of &
----------------------------

I implemented this as a binary-AND for two reasons:
  * Makes the macro, which is used everywhere, more compact and quicker than
using if-statements.
  * Allows for more return types to be added if needed without any change to the
code.

If instead you'd prefer me to write the macro as a big switch:

#define CHECK(S, X) do {
  switch ((X)) {
    case MCDisassembler::Success:
      break;
    case MCDisassembler::SoftFail:
      S = MCDisassembler::SoftFail;
	break;
    case MCDisassembler::Fail:
      S = MCDisassembler::Fail;
    default: llvm_unreachable();
  }

I can, or better possibly as we're going the whole hog and not caring so much
about comparison speed:

bool Check(MCDisassembler::DecodeStatus &Out, MCDisassembler::DecodeStatus In) {
  switch (In) {
    case MCDisassembler::Success:
      return true;
    case MCDisassembler::SoftFail:
      Out = In;
	return true;
    case MCDisassembler::Fail:
      Out = In;
	return false;
    default: llvm_unreachable();
  }
}

Then the CHECK() lines could be changed to:
if (!Check(S, ...)) return MCDisassembler::Fail;

Which would satisfy your above criterion?

Cheers,

James

> -----Original Message-----
> From: Jim Grosbach [mailto:grosbach at apple.com]
> Sent: 30 August 2011 20:15
> To: James Molloy
> Cc: llvm-commits LLVM; Owen Anderson
> Subject: Re: [llvm-commits] [llvm] r137830 - in /llvm/trunk:
> include/llvm/MC/ lib/Target/ARM/Disassembler/
> lib/Target/MBlaze/Disassembler/ lib/Target/X86/Disassembler/
> test/MC/Disassembler/ARM/ tools/llvm-mc/ utils/TableGen/
> 
> ping?
> 
> On Aug 26, 2011, at 11:56 AM, Jim Grosbach wrote:
> 
> > Sorry for the late comments. I missed this catching these bits the first
> time around (saw the patch, just missed this aspect).
> >
> > On Aug 17, 2011, at 10:44 AM, Owen Anderson wrote:
> >
> >> Author: resistor
> >> Date: Wed Aug 17 12:44:15 2011
> >> New Revision: 137830
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=137830&view=rev
> >> Log:
> >> Allow the MCDisassembler to return a "soft fail" status code, indicating
> an instruction that is disassemblable, but invalid.  Only used for ARM
> UNPREDICTABLE instructions at the moment.
> >> Patch by James Molloy.
> >>
> >> Modified:
> >>   llvm/trunk/include/llvm/MC/MCDisassembler.h
> >>   llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
> >>   llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h
> >>   llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.cpp
> >>   llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.h
> >>   llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.cpp
> >>   llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.h
> >>   llvm/trunk/test/MC/Disassembler/ARM/invalid-LDRB_POST-arm.txt
> >>   llvm/trunk/tools/llvm-mc/Disassembler.cpp
> >>   llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp
> >>   llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.cpp
> >>   llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.h
> >>
> >> Modified: llvm/trunk/include/llvm/MC/MCDisassembler.h
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/include/llvm/MC/MCDisassembler.h?rev=137830&r1=137829&r2
> =137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/include/llvm/MC/MCDisassembler.h (original)
> >> +++ llvm/trunk/include/llvm/MC/MCDisassembler.h Wed Aug 17 12:44:15 2011
> >> @@ -25,6 +25,34 @@
> >> ///   and provides an array of assembly instructions.
> >> class MCDisassembler {
> >> public:
> >> +  /// Ternary decode status. Most backends will just use Fail and
> >> +  /// Success, however some have a concept of an instruction with
> >> +  /// understandable semantics but which is architecturally
> >> +  /// incorrect. An example of this is ARM UNPREDICTABLE instructions
> >> +  /// which are disassemblable but cause undefined behaviour.
> >> +  ///
> >> +  /// Because it makes sense to disassemble these instructions, there
> >> +  /// is a "soft fail" failure mode that indicates the MCInst& is
> >> +  /// valid but architecturally incorrect.
> >> +  ///
> >> +  /// The enum numbers are deliberately chosen such that reduction
> >> +  /// from Success->SoftFail ->Fail can be done with a simple
> >> +  /// bitwise-AND:
> >> +  ///
> >> +  ///   LEFT & TOP =  | Success       Unpredictable   Fail
> >> +  ///   --------------+-----------------------------------
> >> +  ///   Success       | Success       Unpredictable   Fail
> >> +  ///   Unpredictable | Unpredictable Unpredictable   Fail
> >> +  ///   Fail          | Fail          Fail            Fail
> >> +  ///
> >> +  /// An easy way of encoding this is as 0b11, 0b01, 0b00 for
> >> +  /// Success, SoftFail, Fail respectively.
> >> +  enum DecodeStatus {
> >> +    Fail = 0,
> >> +    SoftFail = 1,
> >> +    Success = 3
> >> +  };
> >> +
> >>  /// Constructor     - Performs initial setup for the disassembler.
> >>  MCDisassembler() : GetOpInfo(0), DisInfo(0), Ctx(0) {}
> >>
> >> @@ -41,8 +69,11 @@
> >>  /// @param address  - The address, in the memory space of region, of
> the first
> >>  ///                   byte of the instruction.
> >>  /// @param vStream  - The stream to print warnings and diagnostic
> messages on.
> >> -  /// @return         - True if the instruction is valid; false
> otherwise.
> >> -  virtual bool          getInstruction(MCInst& instr,
> >> +  /// @return         - MCDisassembler::Success if the instruction is
> valid,
> >> +  ///                   MCDisassembler::SoftFail if the instruction was
> >> +  ///                                            disassemblable but
> invalid,
> >> +  ///                   MCDisassembler::Fail if the instruction was
> invalid.
> >> +  virtual DecodeStatus  getInstruction(MCInst& instr,
> >>                                       uint64_t& size,
> >>                                       const MemoryObject &region,
> >>                                       uint64_t address,
> >>
> >> Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp?rev=1378
> 30&r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
> (original)
> >> +++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp Wed Aug
> 17 12:44:15 2011
> >> @@ -24,188 +24,201 @@
> >> #include "llvm/Support/ErrorHandling.h"
> >> #include "llvm/Support/raw_ostream.h"
> >>
> >> +// Pull DecodeStatus and its enum values into the global namespace.
> >> +typedef llvm::MCDisassembler::DecodeStatus DecodeStatus;
> >> +#define Success llvm::MCDisassembler::Success
> >> +#define Unpredictable llvm::MCDisassembler::SoftFail
> >> +#define Fail llvm::MCDisassembler::Fail
> >> +
> >
> > Please don't do this sort of thing (#defines to get around scoping).
> Reference the names explicitly, including the scoping operators, instead.
> >
> >> +// Helper macro to perform setwise reduction of the current running
> status
> >> +// and another status, and return if the new status is Fail.
> >> +#define CHECK(S,X) do {                           \
> >> +    S = (DecodeStatus) ((int)S & (X));            \
> >
> > It's better to use the enum values directly rather than casting integers
> like this. The code shouldn't know what the actual values of the enums are.
> >
> >> +    if (S == Fail) return Fail;                   \
> >> +  } while(0)
> >> +
> >
> > Having an early exit buried in a macro obfuscates the code. The way the
> code previously did this is better. Please change this back or refactor
> differently.
> >
> >> // Forward declare these because the autogenerated code will reference
> them.
> >> // Definitions are further down.
> >> -static bool DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >> -static bool DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void
> *Decoder);
> >>
> >> -static bool DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >>
> >> -static bool DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst,
> unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >>
> >> -static bool DecodeMemMultipleWritebackInstruction(llvm::MCInst & Inst,
> >> +static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst
> & Inst,
> >>                                                  unsigned Insn,
> >>                                                  uint64_t Adddress,
> >>                                                  const void *Decoder);
> >> -static bool DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeCoprocessor(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
> >>                               uint64_t Address, const void *Decoder);
> >>
> >>
> >> -static bool DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst,
> uint16_t Insn,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Val,
> >> +static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t
> Val,
> >>                               uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t
> Insn,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned
> Val,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbSRImm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbSRImm(llvm::MCInst &Inst, unsigned Val,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst,
> unsigned Val,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                uint64_t Address, const void *Decoder);
> >> -static bool DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                uint64_t Address, const void *Decoder);
> >>
> >> #include "ARMGenDisassemblerTables.inc"
> >> @@ -230,15 +243,14 @@
> >>  return instInfoARM;
> >> }
> >>
> >> -
> >> -bool ARMDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
> >> -                                     const MemoryObject &Region,
> >> -                                     uint64_t Address,raw_ostream &os)
> const {
> >> +DecodeStatus ARMDisassembler::getInstruction(MCInst &MI, uint64_t
> &Size,
> >> +                                             const MemoryObject
> &Region,
> >> +                                             uint64_t
> Address,raw_ostream &os) const {
> >>  uint8_t bytes[4];
> >>
> >>  // We want to read exactly 4 bytes of data.
> >>  if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  // Encoded as a small-endian 32-bit word in the stream.
> >>  uint32_t insn = (bytes[3] << 24) |
> >> @@ -247,10 +259,10 @@
> >>                  (bytes[0] <<  0);
> >>
> >>  // Calling the auto-generated decoder function.
> >> -  bool result = decodeARMInstruction32(MI, insn, Address, this);
> >> -  if (result) {
> >> +  DecodeStatus result = decodeARMInstruction32(MI, insn, Address,
> this);
> >> +  if (result != Fail) {
> >>    Size = 4;
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  // Instructions that are shared between ARM and Thumb modes.
> >> @@ -258,53 +270,53 @@
> >>  // fact that we fail to encode a few instructions properly for Thumb.
> >>  MI.clear();
> >>  result = decodeCommonInstruction32(MI, insn, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  // VFP and NEON instructions, similarly, are shared between ARM
> >>  // and Thumb modes.
> >>  MI.clear();
> >>  result = decodeVFPInstruction32(MI, insn, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeNEONDataInstruction32(MI, insn, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    // Add a fake predicate operand, because we share these instruction
> >>    // definitions with Thumb2 where these instructions are predicable.
> >> -    if (!DecodePredicateOperand(MI, 0xE, Address, this)) return false;
> >> -    return true;
> >> +    if (!DecodePredicateOperand(MI, 0xE, Address, this)) return Fail;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeNEONLoadStoreInstruction32(MI, insn, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    // Add a fake predicate operand, because we share these instruction
> >>    // definitions with Thumb2 where these instructions are predicable.
> >> -    if (!DecodePredicateOperand(MI, 0xE, Address, this)) return false;
> >> -    return true;
> >> +    if (!DecodePredicateOperand(MI, 0xE, Address, this)) return Fail;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeNEONDupInstruction32(MI, insn, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    // Add a fake predicate operand, because we share these instruction
> >>    // definitions with Thumb2 where these instructions are predicable.
> >> -    if (!DecodePredicateOperand(MI, 0xE, Address, this)) return false;
> >> -    return true;
> >> +    if (!DecodePredicateOperand(MI, 0xE, Address, this)) return Fail;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>
> >> -  return false;
> >> +  return Fail;
> >> }
> >>
> >> namespace llvm {
> >> @@ -403,22 +415,21 @@
> >>  }
> >> }
> >>
> >> -
> >> -bool ThumbDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
> >> -                                       const MemoryObject &Region,
> >> -                                       uint64_t Address,raw_ostream
> &os) const {
> >> +DecodeStatus ThumbDisassembler::getInstruction(MCInst &MI, uint64_t
> &Size,
> >> +                                               const MemoryObject
> &Region,
> >> +                                               uint64_t
> Address,raw_ostream &os) const {
> >>  uint8_t bytes[4];
> >>
> >>  // We want to read exactly 2 bytes of data.
> >>  if (Region.readBytes(Address, 2, (uint8_t*)bytes, NULL) == -1)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  uint16_t insn16 = (bytes[1] << 8) | bytes[0];
> >> -  bool result = decodeThumbInstruction16(MI, insn16, Address, this);
> >> -  if (result) {
> >> +  DecodeStatus result = decodeThumbInstruction16(MI, insn16, Address,
> this);
> >> +  if (result != Fail) {
> >>    Size = 2;
> >>    AddThumbPredicate(MI);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >> @@ -428,12 +439,12 @@
> >>    bool InITBlock = !ITBlock.empty();
> >>    AddThumbPredicate(MI);
> >>    AddThumb1SBit(MI, InITBlock);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeThumb2Instruction16(MI, insn16, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 2;
> >>    AddThumbPredicate(MI);
> >>
> >> @@ -456,12 +467,12 @@
> >>      ITBlock.push_back(firstcond);
> >>    }
> >>
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  // We want to read exactly 4 bytes of data.
> >>  if (Region.readBytes(Address, 4, (uint8_t*)bytes, NULL) == -1)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  uint32_t insn32 = (bytes[3] <<  8) |
> >>                    (bytes[2] <<  0) |
> >> @@ -469,44 +480,44 @@
> >>                    (bytes[0] << 16);
> >>  MI.clear();
> >>  result = decodeThumbInstruction32(MI, insn32, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    bool InITBlock = ITBlock.size();
> >>    AddThumbPredicate(MI);
> >>    AddThumb1SBit(MI, InITBlock);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeThumb2Instruction32(MI, insn32, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    AddThumbPredicate(MI);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeCommonInstruction32(MI, insn32, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    AddThumbPredicate(MI);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeVFPInstruction32(MI, insn32, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    UpdateThumbVFPPredicate(MI);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  MI.clear();
> >>  result = decodeNEONDupInstruction32(MI, insn32, Address, this);
> >> -  if (result) {
> >> +  if (result != Fail) {
> >>    Size = 4;
> >>    AddThumbPredicate(MI);
> >> -    return true;
> >> +    return result;
> >>  }
> >>
> >>  if (fieldFromInstruction32(insn32, 24, 8) == 0xF9) {
> >> @@ -515,10 +526,10 @@
> >>    NEONLdStInsn &= 0xF0FFFFFF;
> >>    NEONLdStInsn |= 0x04000000;
> >>    result = decodeNEONLoadStoreInstruction32(MI, NEONLdStInsn, Address,
> this);
> >> -    if (result) {
> >> +    if (result != Fail) {
> >>      Size = 4;
> >>      AddThumbPredicate(MI);
> >> -      return true;
> >> +      return result;
> >>    }
> >>  }
> >>
> >> @@ -529,14 +540,14 @@
> >>    NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to
> bit 24
> >>    NEONDataInsn |= 0x12000000; // Set bits 28 and 25
> >>    result = decodeNEONDataInstruction32(MI, NEONDataInsn, Address,
> this);
> >> -    if (result) {
> >> +    if (result != Fail) {
> >>      Size = 4;
> >>      AddThumbPredicate(MI);
> >> -      return true;
> >> +      return result;
> >>    }
> >>  }
> >>
> >> -  return false;
> >> +  return Fail;
> >> }
> >>
> >>
> >> @@ -554,30 +565,30 @@
> >>  ARM::R12, ARM::SP, ARM::LR, ARM::PC
> >> };
> >>
> >> -static bool DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeGPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 15)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  unsigned Register = GPRDecoderTable[RegNo];
> >>  Inst.addOperand(MCOperand::CreateReg(Register));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeGPRnopcRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodeGPRnopcRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                       uint64_t Address, const void
> *Decoder) {
> >> -  if (RegNo == 15) return false;
> >> +  if (RegNo == 15) return Fail;
> >>  return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
> >> }
> >>
> >> -static bool DecodetGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodetGPRRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 7)
> >> -    return false;
> >> +    return Fail;
> >>  return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
> >> }
> >>
> >> -static bool DecodetcGPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodetcGPRRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  unsigned Register = 0;
> >>  switch (RegNo) {
> >> @@ -600,16 +611,16 @@
> >>      Register = ARM::R12;
> >>      break;
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    }
> >>
> >>  Inst.addOperand(MCOperand::CreateReg(Register));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecoderGPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecoderGPRRegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >> -  if (RegNo == 13 || RegNo == 15) return false;
> >> +  if (RegNo == 13 || RegNo == 15) return Fail;
> >>  return DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder);
> >> }
> >>
> >> @@ -624,14 +635,14 @@
> >>    ARM::S28, ARM::S29, ARM::S30, ARM::S31
> >> };
> >>
> >> -static bool DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeSPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 31)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  unsigned Register = SPRDecoderTable[RegNo];
> >>  Inst.addOperand(MCOperand::CreateReg(Register));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> static const unsigned DPRDecoderTable[] = {
> >> @@ -645,27 +656,27 @@
> >>    ARM::D28, ARM::D29, ARM::D30, ARM::D31
> >> };
> >>
> >> -static bool DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeDPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 31)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  unsigned Register = DPRDecoderTable[RegNo];
> >>  Inst.addOperand(MCOperand::CreateReg(Register));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeDPR_8RegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodeDPR_8RegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 7)
> >> -    return false;
> >> +    return Fail;
> >>  return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
> >> }
> >>
> >> -static bool DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >> +static DecodeStatus DecodeDPR_VFP2RegisterClass(llvm::MCInst &Inst,
> unsigned RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 15)
> >> -    return false;
> >> +    return Fail;
> >>  return DecodeDPRRegisterClass(Inst, RegNo, Address, Decoder);
> >> }
> >>
> >> @@ -677,65 +688,66 @@
> >> };
> >>
> >>
> >> -static bool DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned RegNo,
> >> +static DecodeStatus DecodeQPRRegisterClass(llvm::MCInst &Inst, unsigned
> RegNo,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  if (RegNo > 31)
> >> -    return false;
> >> +    return Fail;
> >>  RegNo >>= 1;
> >>
> >>  unsigned Register = QPRDecoderTable[RegNo];
> >>  Inst.addOperand(MCOperand::CreateReg(Register));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodePredicateOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodePredicateOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >> -  if (Val == 0xF) return false;
> >> +  if (Val == 0xF) return Fail;
> >>  // AL predicate is not allowed on Thumb1 branches.
> >>  if (Inst.getOpcode() == ARM::tBcc && Val == 0xE)
> >> -    return false;
> >> +    return Fail;
> >>  Inst.addOperand(MCOperand::CreateImm(Val));
> >>  if (Val == ARMCC::AL) {
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  } else
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  if (Val)
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::CPSR));
> >>  else
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  uint32_t imm = Val & 0xFF;
> >>  uint32_t rot = (Val & 0xF00) >> 7;
> >>  uint32_t rot_imm = (imm >> rot) | (imm << (32-rot));
> >>  Inst.addOperand(MCOperand::CreateImm(rot_imm));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  Val <<= 2;
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(Val)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >>
> >>  unsigned Rm = fieldFromInstruction32(Val, 0, 4);
> >>  unsigned type = fieldFromInstruction32(Val, 5, 2);
> >>  unsigned imm = fieldFromInstruction32(Val, 7, 5);
> >>
> >>  // Register-immediate
> >> -  if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>
> >>  ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
> >>  switch (type) {
> >> @@ -759,19 +771,20 @@
> >>  unsigned Op = Shift | (imm << 3);
> >>  Inst.addOperand(MCOperand::CreateImm(Op));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSORegRegOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >>
> >>  unsigned Rm = fieldFromInstruction32(Val, 0, 4);
> >>  unsigned type = fieldFromInstruction32(Val, 5, 2);
> >>  unsigned Rs = fieldFromInstruction32(Val, 8, 4);
> >>
> >>  // Register-register
> >> -  if (!DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder));
> >> +  CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rs, Address, Decoder));
> >>
> >>  ARM_AM::ShiftOpc Shift = ARM_AM::lsl;
> >>  switch (type) {
> >> @@ -791,49 +804,55 @@
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(Shift));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  // Empty register lists are not allowed.
> >> -  if (CountPopulation_32(Val) == 0) return false;
> >> +  if (CountPopulation_32(Val) == 0) return Fail;
> >>  for (unsigned i = 0; i < 16; ++i) {
> >>    if (Val & (1 << i)) {
> >> -      if (!DecodeGPRRegisterClass(Inst, i, Address, Decoder)) return
> false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder));
> >>    }
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Vd = fieldFromInstruction32(Val, 8, 4);
> >>  unsigned regs = Val & 0xFF;
> >>
> >> -  if (!DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder));
> >>  for (unsigned i = 0; i < (regs - 1); ++i) {
> >> -    if (!DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeSPRRegisterClass(Inst, ++Vd, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeDPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeDPRRegListOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Vd = fieldFromInstruction32(Val, 8, 4);
> >>  unsigned regs = (Val & 0xFF) / 2;
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder));
> >>  for (unsigned i = 0; i < (regs - 1); ++i) {
> >> -    if (!DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeDPRRegisterClass(Inst, ++Vd, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeBitfieldMaskOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeBitfieldMaskOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                      uint64_t Address, const void
> *Decoder) {
> >>  // This operand encodes a mask of contiguous zeros between a specified
> MSB
> >>  // and LSB.  To decode it, we create the mask of all bits MSB-and-
> lower,
> >> @@ -845,11 +864,13 @@
> >>  uint32_t msb_mask = (1 << (msb+1)) - 1;
> >>  uint32_t lsb_mask = (1 << lsb) - 1;
> >>  Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>  unsigned CRd = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned coproc = fieldFromInstruction32(Insn, 8, 4);
> >> @@ -875,7 +896,7 @@
> >>    case ARM::STCL_POST:
> >>    case ARM::STCL_OPTION:
> >>      if (coproc == 0xA || coproc == 0xB)
> >> -        return false;
> >> +        return Fail;
> >>      break;
> >>    default:
> >>      break;
> >> @@ -883,7 +904,7 @@
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(coproc));
> >>  Inst.addOperand(MCOperand::CreateImm(CRd));
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  switch (Inst.getOpcode()) {
> >>    case ARM::LDC_OPTION:
> >>    case ARM::LDCL_OPTION:
> >> @@ -952,17 +973,19 @@
> >>    case ARM::STCL_PRE:
> >>    case ARM::STCL_POST:
> >>    case ARM::STCL_OPTION:
> >> -      if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +      CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeAddrMode2IdxInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >> @@ -982,13 +1005,13 @@
> >>    case ARM::STRT_POST_IMM:
> >>    case ARM::STRBT_POST_REG:
> >>    case ARM::STRBT_POST_IMM:
> >> -      if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >>
> >>  // On loads, the writeback operand comes after Rt.
> >>  switch (Inst.getOpcode()) {
> >> @@ -1002,14 +1025,13 @@
> >>    case ARM::LDRBT_POST_IMM:
> >>    case ARM::LDRT_POST_REG:
> >>    case ARM::LDRT_POST_IMM:
> >> -      if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -        return false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>
> >>  ARM_AM::AddrOpc Op = ARM_AM::add;
> >>  if (!fieldFromInstruction32(Insn, 23, 1))
> >> @@ -1022,10 +1044,10 @@
> >>  else if (!P && writeback)
> >>    idx_mode = ARMII::IndexModePost;
> >>
> >> -  if (writeback && (Rn == 15 || Rn == Rt)) return false; //
> UNPREDICTABLE
> >> +  if (writeback && (Rn == 15 || Rn == Rt)) S = Unpredictable; //
> UNPREDICTABLE
> >>
> >>  if (reg) {
> >> -    if (!DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder));
> >>    ARM_AM::ShiftOpc Opc = ARM_AM::lsl;
> >>    switch( fieldFromInstruction32(Insn, 5, 2)) {
> >>      case 0:
> >> @@ -1041,7 +1063,7 @@
> >>        Opc = ARM_AM::ror;
> >>        break;
> >>      default:
> >> -        return false;
> >> +        return Fail;
> >>    }
> >>    unsigned amt = fieldFromInstruction32(Insn, 7, 5);
> >>    unsigned imm = ARM_AM::getAM2Opc(Op, amt, Opc, idx_mode);
> >> @@ -1053,13 +1075,15 @@
> >>    Inst.addOperand(MCOperand::CreateImm(tmp));
> >>  }
> >>
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeSORegMemOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 13, 4);
> >>  unsigned Rm = fieldFromInstruction32(Val,  0, 4);
> >>  unsigned type = fieldFromInstruction32(Val, 5, 2);
> >> @@ -1082,8 +1106,8 @@
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  unsigned shift;
> >>  if (U)
> >>    shift = ARM_AM::getAM2Opc(ARM_AM::add, imm, ShOp);
> >> @@ -1091,11 +1115,13 @@
> >>    shift = ARM_AM::getAM2Opc(ARM_AM::sub, imm, ShOp);
> >>  Inst.addOperand(MCOperand::CreateImm(shift));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeAddrMode3Instruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >> @@ -1116,7 +1142,7 @@
> >>    case ARM::LDRD:
> >>    case ARM::LDRD_PRE:
> >>    case ARM::LDRD_POST:
> >> -      if (Rt & 0x1) return false;
> >> +      if (Rt & 0x1) return Fail;
> >>      break;
> >>  default:
> >>    break;
> >> @@ -1136,16 +1162,14 @@
> >>    case ARM::STRH:
> >>    case ARM::STRH_PRE:
> >>    case ARM::STRH_POST:
> >> -      if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -        return false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>    }
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >>  switch (Inst.getOpcode()) {
> >>    case ARM::STRD:
> >>    case ARM::STRD_PRE:
> >> @@ -1153,8 +1177,7 @@
> >>    case ARM::LDRD:
> >>    case ARM::LDRD_PRE:
> >>    case ARM::LDRD_POST:
> >> -      if (!DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder))
> >> -        return false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >> @@ -1177,33 +1200,32 @@
> >>    case ARM::LDRSB_POST:
> >>    case ARM::LDRHTr:
> >>    case ARM::LDRSBTr:
> >> -      if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -        return false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>    }
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>
> >>  if (type) {
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>    Inst.addOperand(MCOperand::CreateImm(U | (imm << 4) | Rm));
> >>  } else {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>    Inst.addOperand(MCOperand::CreateImm(U));
> >>  }
> >>
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeRFEInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeRFEInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned mode = fieldFromInstruction32(Insn, 23, 2);
> >>
> >> @@ -1223,14 +1245,16 @@
> >>  }
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(mode));
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeMemMultipleWritebackInstruction(llvm::MCInst &Inst,
> >> +static DecodeStatus DecodeMemMultipleWritebackInstruction(llvm::MCInst
> &Inst,
> >>                                  unsigned Insn,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>  unsigned reglist = fieldFromInstruction32(Insn, 0, 16);
> >> @@ -1265,16 +1289,15 @@
> >>    return DecodeRFEInstruction(Inst, Insn, Address, Decoder);
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)   ||
> >> -      !DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)   || // Tied
> >> -      !DecodePredicateOperand(Inst, pred, Address, Decoder) ||
> >> -      !DecodeRegListOperand(Inst, reglist, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)); // Tied
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >> +  CHECK(S, DecodeRegListOperand(Inst, reglist, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeCPSInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeCPSInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                 uint64_t Address, const void *Decoder) {
> >>  unsigned imod = fieldFromInstruction32(Insn, 18, 2);
> >>  unsigned M = fieldFromInstruction32(Insn, 17, 1);
> >> @@ -1282,30 +1305,32 @@
> >>  unsigned mode = fieldFromInstruction32(Insn, 0, 5);
> >>
> >>  // imod == '01' --> UNPREDICTABLE
> >> -  if (imod == 1) return false;
> >> +  if (imod == 1) return Fail;
> >>
> >>  if (M && mode && imod && iflags) {
> >>    Inst.setOpcode(ARM::CPS3p);
> >>    Inst.addOperand(MCOperand::CreateImm(imod));
> >>    Inst.addOperand(MCOperand::CreateImm(iflags));
> >>    Inst.addOperand(MCOperand::CreateImm(mode));
> >> -    return true;
> >> +    return Success;
> >>  } else if (!mode && !M) {
> >>    Inst.setOpcode(ARM::CPS2p);
> >>    Inst.addOperand(MCOperand::CreateImm(imod));
> >>    Inst.addOperand(MCOperand::CreateImm(iflags));
> >> -    return true;
> >> +    return Success;
> >>  } else if (!imod && !iflags && M) {
> >>    Inst.setOpcode(ARM::CPS1p);
> >>    Inst.addOperand(MCOperand::CreateImm(mode));
> >> -    return true;
> >> +    return Success;
> >>  }
> >>
> >> -  return false;
> >> +  return Fail;
> >> }
> >>
> >> -static bool DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSMLAInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rn = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 8, 4);
> >> @@ -1315,57 +1340,60 @@
> >>  if (pred == 0xF)
> >>    return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
> >>
> >> -  if (!DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder) ||
> >> -      !DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder) ||
> >> -      !DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder) ||
> >> -      !DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder));
> >> +  CHECK(S, DecodeGPRnopcRegisterClass(Inst, Ra, Address, Decoder));
> >>
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeAddrModeImm12Operand(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeAddrModeImm12Operand(llvm::MCInst &Inst,
> unsigned Val,
> >>                           uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned add = fieldFromInstruction32(Val, 12, 1);
> >>  unsigned imm = fieldFromInstruction32(Val, 0, 12);
> >>  unsigned Rn = fieldFromInstruction32(Val, 13, 4);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>
> >>  if (!add) imm *= -1;
> >>  if (imm == 0 && !add) imm = INT32_MIN;
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeAddrMode5Operand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 9, 4);
> >>  unsigned U = fieldFromInstruction32(Val, 8, 1);
> >>  unsigned imm = fieldFromInstruction32(Val, 0, 8);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>
> >>  if (U)
> >>    Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::add,
> imm)));
> >>  else
> >>    Inst.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(ARM_AM::sub,
> imm)));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeAddrMode7Operand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  return DecodeGPRRegisterClass(Inst, Val, Address, Decoder);
> >> }
> >>
> >> -static bool DecodeBranchImmInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeBranchImmInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>  unsigned imm = fieldFromInstruction32(Insn, 0, 24) << 2;
> >>
> >> @@ -1373,39 +1401,42 @@
> >>    Inst.setOpcode(ARM::BLXi);
> >>    imm |= fieldFromInstruction32(Insn, 24, 1) << 1;
> >>    Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
> >> -    return true;
> >> +    return S;
> >>  }
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(imm)));
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVCVTImmOperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(64 - Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeAddrMode6Operand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rm = fieldFromInstruction32(Val, 0, 4);
> >>  unsigned align = fieldFromInstruction32(Val, 4, 2);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  if (!align)
> >>    Inst.addOperand(MCOperand::CreateImm(0));
> >>  else
> >>    Inst.addOperand(MCOperand::CreateImm(4 << align));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVLDInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLDInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned wb = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -1414,7 +1445,7 @@
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>
> >>  // First output register
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>
> >>  // Second output register
> >>  switch (Inst.getOpcode()) {
> >> @@ -1466,7 +1497,7 @@
> >>    case ARM::VLD4d8_UPD:
> >>    case ARM::VLD4d16_UPD:
> >>    case ARM::VLD4d32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address,
> Decoder));
> >>      break;
> >>    case ARM::VLD2b8:
> >>    case ARM::VLD2b16:
> >> @@ -1486,7 +1517,7 @@
> >>    case ARM::VLD4q8_UPD:
> >>    case ARM::VLD4q16_UPD:
> >>    case ARM::VLD4q32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address,
> Decoder));
> >>    default:
> >>      break;
> >>  }
> >> @@ -1527,7 +1558,7 @@
> >>    case ARM::VLD4d8_UPD:
> >>    case ARM::VLD4d16_UPD:
> >>    case ARM::VLD4d32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address,
> Decoder));
> >>      break;
> >>    case ARM::VLD3q8:
> >>    case ARM::VLD3q16:
> >> @@ -1541,7 +1572,7 @@
> >>    case ARM::VLD4q8_UPD:
> >>    case ARM::VLD4q16_UPD:
> >>    case ARM::VLD4q32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address,
> Decoder));
> >>      break;
> >>    default:
> >>      break;
> >> @@ -1569,7 +1600,7 @@
> >>    case ARM::VLD4d8_UPD:
> >>    case ARM::VLD4d16_UPD:
> >>    case ARM::VLD4d32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address,
> Decoder));
> >>      break;
> >>    case ARM::VLD4q8:
> >>    case ARM::VLD4q16:
> >> @@ -1577,7 +1608,7 @@
> >>    case ARM::VLD4q8_UPD:
> >>    case ARM::VLD4q16_UPD:
> >>    case ARM::VLD4q32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address,
> Decoder));
> >>      break;
> >>    default:
> >>      break;
> >> @@ -1622,28 +1653,29 @@
> >>    case ARM::VLD4q8_UPD:
> >>    case ARM::VLD4q16_UPD:
> >>    case ARM::VLD4q32_UPD:
> >> -      if (!DecodeGPRRegisterClass(Inst, wb, Address, Decoder)) return
> false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >>  // AddrMode6 Base (register+alignment)
> >> -  if (!DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder));
> >>
> >>  // AddrMode6 Offset (register)
> >>  if (Rm == 0xD)
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  else if (Rm != 0xF) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVSTInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVSTInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned wb = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -1690,25 +1722,24 @@
> >>    case ARM::VST4q8_UPD:
> >>    case ARM::VST4q16_UPD:
> >>    case ARM::VST4q32_UPD:
> >> -      if (!DecodeGPRRegisterClass(Inst, wb, Address, Decoder))
> >> -        return false;
> >> +      CHECK(S, DecodeGPRRegisterClass(Inst, wb, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >>  // AddrMode6 Base (register+alignment)
> >> -  if (!DecodeAddrMode6Operand(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeAddrMode6Operand(Inst, Rn, Address, Decoder));
> >>
> >>  // AddrMode6 Offset (register)
> >>  if (Rm == 0xD)
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  else if (Rm != 0xF) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >>  // First input register
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>
> >>  // Second input register
> >>  switch (Inst.getOpcode()) {
> >> @@ -1760,7 +1791,7 @@
> >>    case ARM::VST4d8_UPD:
> >>    case ARM::VST4d16_UPD:
> >>    case ARM::VST4d32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address,
> Decoder));
> >>      break;
> >>    case ARM::VST2b8:
> >>    case ARM::VST2b16:
> >> @@ -1780,7 +1811,7 @@
> >>    case ARM::VST4q8_UPD:
> >>    case ARM::VST4q16_UPD:
> >>    case ARM::VST4q32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address,
> Decoder));
> >>      break;
> >>    default:
> >>      break;
> >> @@ -1822,7 +1853,7 @@
> >>    case ARM::VST4d8_UPD:
> >>    case ARM::VST4d16_UPD:
> >>    case ARM::VST4d32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2)%32, Address,
> Decoder));
> >>      break;
> >>    case ARM::VST3q8:
> >>    case ARM::VST3q16:
> >> @@ -1836,7 +1867,7 @@
> >>    case ARM::VST4q8_UPD:
> >>    case ARM::VST4q16_UPD:
> >>    case ARM::VST4q32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+4)%32, Address,
> Decoder));
> >>      break;
> >>    default:
> >>      break;
> >> @@ -1864,7 +1895,7 @@
> >>    case ARM::VST4d8_UPD:
> >>    case ARM::VST4d16_UPD:
> >>    case ARM::VST4d32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+3)%32, Address,
> Decoder));
> >>      break;
> >>    case ARM::VST4q8:
> >>    case ARM::VST4q16:
> >> @@ -1872,17 +1903,19 @@
> >>    case ARM::VST4q8_UPD:
> >>    case ARM::VST4q16_UPD:
> >>    case ARM::VST4q32_UPD:
> >> -      if (!DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address, Decoder))
> return false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+6)%32, Address,
> Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVLD1DupInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD1DupInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                    uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -1893,28 +1926,30 @@
> >>
> >>  align *= (1 << size);
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  if (regs == 2) {
> >> -    if (!DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address, Decoder))
> return false;
> >> +    CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+1)%32, Address,
> Decoder));
> >>  }
> >>  if (Rm == 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>
> >>  if (Rm == 0xD)
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  else if (Rm != 0xF) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVLD2DupInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD2DupInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                    uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -1924,54 +1959,57 @@
> >>  unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
> >>  align *= 2*size;
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder))
> return false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address,
> Decoder));
> >>  if (Rm == 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>
> >>  if (Rm == 0xD)
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  else if (Rm != 0xF) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVLD3DupInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD3DupInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                    uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned inc = fieldFromInstruction32(Insn, 5, 1) + 1;
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)          ||
> >> -      !DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder) ||
> >> -      !DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address,
> Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address,
> Decoder));
> >>  if (Rm == 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(0));
> >>
> >>  if (Rm == 0xD)
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  else if (Rm != 0xF) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVLD4DupInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD4DupInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                    uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -1993,29 +2031,30 @@
> >>    }
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)            ||
> >> -      !DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address, Decoder)   ||
> >> -      !DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address, Decoder) ||
> >> -      !DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+inc)%32, Address,
> Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+2*inc)%32, Address,
> Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, (Rd+3*inc)%32, Address,
> Decoder));
> >>  if (Rm == 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>
> >>  if (Rm == 0xD)
> >>    Inst.addOperand(MCOperand::CreateReg(0));
> >>  else if (Rm != 0xF) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeNEONModImmInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeNEONModImmInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                        uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned imm = fieldFromInstruction32(Insn, 0, 4);
> >> @@ -2026,9 +2065,9 @@
> >>  unsigned Q = fieldFromInstruction32(Insn, 6, 1);
> >>
> >>  if (Q) {
> >> -    if (!DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  } else {
> >> -    if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  }
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >> @@ -2038,62 +2077,66 @@
> >>    case ARM::VORRiv2i32:
> >>    case ARM::VBICiv4i16:
> >>    case ARM::VBICiv2i32:
> >> -      if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +      CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>      break;
> >>    case ARM::VORRiv8i16:
> >>    case ARM::VORRiv4i32:
> >>    case ARM::VBICiv8i16:
> >>    case ARM::VBICiv4i32:
> >> -      if (!DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +      CHECK(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder));
> >>      break;
> >>    default:
> >>      break;
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVSHLMaxInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVSHLMaxInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                        uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  Rm |= fieldFromInstruction32(Insn, 5, 1) << 4;
> >>  unsigned size = fieldFromInstruction32(Insn, 18, 2);
> >>
> >> -  if (!DecodeQPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeQPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(8 << size));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight8Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(8 - Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight16Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(16 - Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight32Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(32 - Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeShiftRight64Imm(llvm::MCInst &Inst, unsigned
> Val,
> >>                               uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(64 - Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeTBLInstruction(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeTBLInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >>                               uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  Rd |= fieldFromInstruction32(Insn, 22, 1) << 4;
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -2103,21 +2146,21 @@
> >>  unsigned op = fieldFromInstruction32(Insn, 6, 1);
> >>  unsigned length = fieldFromInstruction32(Insn, 8, 2) + 1;
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  if (op) {
> >> -    if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false; // Writeback
> >> +    CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)); //
> Writeback
> >>  }
> >>
> >>  for (unsigned i = 0; i < length; ++i) {
> >> -    if (!DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address, Decoder))
> return false;
> >> +    CHECK(S, DecodeDPRRegisterClass(Inst, (Rn+i)%32, Address,
> Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rm, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeVFPfpImm(llvm::MCInst &Inst, unsigned Val,
> >>                            uint64_t Address, const void *Decoder) {
> >>  // The immediate needs to be a fully instantiated float.  However, the
> >>  // auto-generated decoder is only able to fill in some of the bits
> >> @@ -2139,102 +2182,110 @@
> >>  fp_conv.integer |= (~b & 0x1) << 30;
> >>
> >>  Inst.addOperand(MCOperand::CreateFPImm(fp_conv.fp));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbAddSpecialReg(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbAddSpecialReg(llvm::MCInst &Inst,
> uint16_t Insn,
> >>                                     uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned dst = fieldFromInstruction16(Insn, 8, 3);
> >>  unsigned imm = fieldFromInstruction16(Insn, 0, 8);
> >>
> >> -  if (!DecodetGPRRegisterClass(Inst, dst, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodetGPRRegisterClass(Inst, dst, Address, Decoder));
> >>
> >>  if (Inst.getOpcode() == ARM::tADR)
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::PC));
> >>  else if (Inst.getOpcode() == ARM::tADDrSPi)
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::SP));
> >>  else
> >> -    return false;
> >> +    return Fail;
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeThumbBROperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbBROperand(llvm::MCInst &Inst, unsigned
> Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<12>(Val << 1)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2BROperand(llvm::MCInst &Inst, unsigned Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<21>(Val)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbCmpBROperand(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbCmpBROperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<7>(Val << 1)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModeRR(llvm::MCInst &Inst, unsigned
> Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 0, 3);
> >>  unsigned Rm = fieldFromInstruction32(Val, 3, 3);
> >>
> >> -  if (!DecodetGPRRegisterClass(Inst, Rn, Address, Decoder) ||
> >> -      !DecodetGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodetGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModeIS(llvm::MCInst &Inst, unsigned
> Val,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 0, 3);
> >>  unsigned imm = fieldFromInstruction32(Val, 3, 5);
> >>
> >> -  if (!DecodetGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodetGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModePC(llvm::MCInst &Inst, unsigned
> Val,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >>  Inst.addOperand(MCOperand::CreateImm(Val << 2));
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbAddrModeSP(llvm::MCInst &Inst, unsigned
> Val,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >>  Inst.addOperand(MCOperand::CreateReg(ARM::SP));
> >>  Inst.addOperand(MCOperand::CreateImm(Val << 2));
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeSOReg(llvm::MCInst &Inst, unsigned
> Val,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 6, 4);
> >>  unsigned Rm = fieldFromInstruction32(Val, 2, 4);
> >>  unsigned imm = fieldFromInstruction32(Val, 0, 2);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder) ||
> >> -      !DecoderGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeT2LoadShift(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeT2LoadShift(llvm::MCInst &Inst, unsigned
> Insn,
> >>                              uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  if (Inst.getOpcode() != ARM::t2PLDs) {
> >>    unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
> >> -    if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >>  }
> >>
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >> @@ -2257,57 +2308,60 @@
> >>        Inst.addOperand(MCOperand::CreateReg(ARM::PC));
> >>        break;
> >>      default:
> >> -        return false;
> >> +        return Fail;
> >>    }
> >>
> >>    int imm = fieldFromInstruction32(Insn, 0, 12);
> >>    if (!fieldFromInstruction32(Insn, 23, 1)) imm *= -1;
> >>    Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -    return true;
> >> +    return S;
> >>  }
> >>
> >>  unsigned addrmode = fieldFromInstruction32(Insn, 4, 2);
> >>  addrmode |= fieldFromInstruction32(Insn, 0, 4) << 2;
> >>  addrmode |= fieldFromInstruction32(Insn, 16, 4) << 6;
> >> -  DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder);
> >> +  CHECK(S, DecodeT2AddrModeSOReg(Inst, addrmode, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2Imm8S4(llvm::MCInst &Inst, unsigned Val,
> >>                           uint64_t Address, const void *Decoder) {
> >>  int imm = Val & 0xFF;
> >>  if (!(Val & 0x100)) imm *= -1;
> >>  Inst.addOperand(MCOperand::CreateImm(imm << 2));
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeImm8s4(llvm::MCInst &Inst, unsigned
> Val,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 9, 4);
> >>  unsigned imm = fieldFromInstruction32(Val, 0, 9);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder) ||
> >> -      !DecodeT2Imm8S4(Inst, imm, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeT2Imm8S4(Inst, imm, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2Imm8(llvm::MCInst &Inst, unsigned Val,
> >>                         uint64_t Address, const void *Decoder) {
> >>  int imm = Val & 0xFF;
> >>  if (!(Val & 0x100)) imm *= -1;
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >>
> >> -static bool DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeImm8(llvm::MCInst &Inst, unsigned
> Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 9, 4);
> >>  unsigned imm = fieldFromInstruction32(Val, 0, 9);
> >>
> >> @@ -2324,27 +2378,28 @@
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder) ||
> >> -      !DecodeT2Imm8(Inst, imm, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeT2Imm8(Inst, imm, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2AddrModeImm12(llvm::MCInst &Inst, unsigned
> Val,
> >>                                  uint64_t Address, const void *Decoder)
> {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Val, 13, 4);
> >>  unsigned imm = fieldFromInstruction32(Val, 0, 12);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbAddSPImm(llvm::MCInst &Inst, uint16_t
> Insn,
> >>                                uint64_t Address, const void *Decoder) {
> >>  unsigned imm = fieldFromInstruction16(Insn, 0, 7);
> >>
> >> @@ -2352,30 +2407,32 @@
> >>  Inst.addOperand(MCOperand::CreateReg(ARM::SP));
> >>  Inst.addOperand(MCOperand::CreateImm(imm));
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbAddSPReg(llvm::MCInst &Inst, uint16_t
> Insn,
> >>                                uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  if (Inst.getOpcode() == ARM::tADDrSP) {
> >>    unsigned Rdm = fieldFromInstruction16(Insn, 0, 3);
> >>    Rdm |= fieldFromInstruction16(Insn, 7, 1) << 3;
> >>
> >> -    if (!DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder));
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::SP));
> >> -    if (!DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rdm, Address, Decoder));
> >>  } else if (Inst.getOpcode() == ARM::tADDspr) {
> >>    unsigned Rm = fieldFromInstruction16(Insn, 3, 4);
> >>
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::SP));
> >>    Inst.addOperand(MCOperand::CreateReg(ARM::SP));
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
> >> +static DecodeStatus DecodeThumbCPS(llvm::MCInst &Inst, uint16_t Insn,
> >>                           uint64_t Address, const void *Decoder) {
> >>  unsigned imod = fieldFromInstruction16(Insn, 4, 1) | 0x2;
> >>  unsigned flags = fieldFromInstruction16(Insn, 0, 3);
> >> @@ -2383,52 +2440,55 @@
> >>  Inst.addOperand(MCOperand::CreateImm(imod));
> >>  Inst.addOperand(MCOperand::CreateImm(flags));
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodePostIdxReg(llvm::MCInst &Inst, unsigned Insn,
> >>                             uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned add = fieldFromInstruction32(Insn, 4, 1);
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)) ;
> >>  Inst.addOperand(MCOperand::CreateImm(add));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbBLXOffset(llvm::MCInst &Inst, unsigned
> Val,
> >>                                 uint64_t Address, const void *Decoder) {
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeCoprocessor(llvm::MCInst &Inst, unsigned Val,
> >>                              uint64_t Address, const void *Decoder) {
> >>  if (Val == 0xA || Val == 0xB)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbSRImm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeThumbSRImm(llvm::MCInst &Inst, unsigned Val,
> >>                             uint64_t Address, const void *Decoder) {
> >>  if (Val == 0)
> >>    Inst.addOperand(MCOperand::CreateImm(32));
> >>  else
> >>    Inst.addOperand(MCOperand::CreateImm(Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumb2BCCInstruction(llvm::MCInst &Inst, unsigned
> Insn,
> >> +static DecodeStatus DecodeThumb2BCCInstruction(llvm::MCInst &Inst,
> unsigned Insn,
> >>                                       uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned pred = fieldFromInstruction32(Insn, 22, 4);
> >>  if (pred == 0xE || pred == 0xF) {
> >>    unsigned opc = fieldFromInstruction32(Insn, 4, 2);
> >>    switch (opc) {
> >>      default:
> >> -        return false;
> >> +        return Fail;
> >>      case 0:
> >>        Inst.setOpcode(ARM::t2DSB);
> >>        break;
> >> @@ -2437,7 +2497,7 @@
> >>        break;
> >>      case 2:
> >>        Inst.setOpcode(ARM::t2ISB);
> >> -        return true;
> >> +        return Success;
> >>    }
> >>
> >>    unsigned imm = fieldFromInstruction32(Insn, 0, 4);
> >> @@ -2450,17 +2510,16 @@
> >>  brtarget |= fieldFromInstruction32(Insn, 16, 6) << 12;
> >>  brtarget |= fieldFromInstruction32(Insn, 26, 1) << 20;
> >>
> >> -  if (!DecodeT2BROperand(Inst, brtarget, Address, Decoder) ||
> >> -      !DecodePredicateOperand(Inst, pred, Address, Decoder))
> >> -    return false;
> >> +  CHECK(S, DecodeT2BROperand(Inst, brtarget, Address, Decoder));
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> // Decode a shifted immediate operand.  These basically consist
> >> // of an 8-bit value, and a 4-bit directive that specifies either
> >> // a splat operation or a rotation.
> >> -static bool DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeT2SOImm(llvm::MCInst &Inst, unsigned Val,
> >>                          uint64_t Address, const void *Decoder) {
> >>  unsigned ctrl = fieldFromInstruction32(Val, 10, 2);
> >>  if (ctrl == 0) {
> >> @@ -2488,26 +2547,26 @@
> >>    Inst.addOperand(MCOperand::CreateImm(imm));
> >>  }
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbBCCTargetOperand(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeThumbBCCTargetOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                        uint64_t Address, const void
> *Decoder){
> >>  Inst.addOperand(MCOperand::CreateImm(Val << 1));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeThumbBLTargetOperand(llvm::MCInst &Inst, unsigned
> Val,
> >> +static DecodeStatus DecodeThumbBLTargetOperand(llvm::MCInst &Inst,
> unsigned Val,
> >>                                       uint64_t Address, const void
> *Decoder){
> >>  Inst.addOperand(MCOperand::CreateImm(SignExtend32<22>(Val << 1)));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeMemBarrierOption(llvm::MCInst &Inst, unsigned
> Val,
> >>                                   uint64_t Address, const void *Decoder)
> {
> >>  switch (Val) {
> >>  default:
> >> -    return false;
> >> +    return Fail;
> >>  case 0xF: // SY
> >>  case 0xE: // ST
> >>  case 0xB: // ISH
> >> @@ -2520,55 +2579,61 @@
> >>  }
> >>
> >>  Inst.addOperand(MCOperand::CreateImm(Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
> >> +static DecodeStatus DecodeMSRMask(llvm::MCInst &Inst, unsigned Val,
> >>                          uint64_t Address, const void *Decoder) {
> >> -  if (!Val) return false;
> >> +  if (!Val) return Fail;
> >>  Inst.addOperand(MCOperand::CreateImm(Val));
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> -static bool DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeDoubleRegLoad(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                          uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>
> >> -  if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return false;
> >> +  if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return Fail;
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeDoubleRegStore(llvm::MCInst &Inst, unsigned
> Insn,
> >>                                          uint64_t Address, const void
> *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned Rt = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>
> >> -  if (!DecoderGPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecoderGPRRegisterClass(Inst, Rd, Address, Decoder));
> >>
> >> -  if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return false;
> >> -  if (Rd == Rn || Rd == Rt || Rd == Rt+1) return false;
> >> +  if ((Rt & 1) || Rt == 0xE || Rn == 0xF) return Fail;
> >> +  if (Rd == Rn || Rd == Rt || Rd == Rt+1) return Fail;
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt+1, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSTRPreImm(llvm::MCInst &Inst, unsigned Insn,
> >>                            uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned imm = fieldFromInstruction32(Insn, 0, 12);
> >> @@ -2576,18 +2641,20 @@
> >>  imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>
> >> -  if (Rn == 0xF || Rn == Rt) return false; // UNPREDICTABLE
> >> +  if (Rn == 0xF || Rn == Rt) return Unpredictable; // UNPREDICTABLE
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)) return
> false;
> >> -  if (!DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder)) return
> false;
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >> +  CHECK(S, DecodeAddrModeImm12Operand(Inst, imm, Address, Decoder));
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeSTRPreReg(llvm::MCInst &Inst, unsigned Insn,
> >>                            uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rt = fieldFromInstruction32(Insn, 12, 4);
> >>  unsigned imm = fieldFromInstruction32(Insn, 0, 12);
> >> @@ -2595,18 +2662,20 @@
> >>  imm |= fieldFromInstruction32(Insn, 23, 1) << 12;
> >>  unsigned pred = fieldFromInstruction32(Insn, 28, 4);
> >>
> >> -  if (Rn == 0xF || Rn == Rt) return false; // UNPREDICTABLE
> >> +  if (Rn == 0xF || Rn == Rt) return Unpredictable; // UNPREDICTABLE
> >>
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> -  if (!DecodeGPRRegisterClass(Inst, Rt, Address, Decoder)) return
> false;
> >> -  if (!DecodeSORegMemOperand(Inst, imm, Address, Decoder)) return
> false;
> >> -  if (!DecodePredicateOperand(Inst, pred, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rt, Address, Decoder));
> >> +  CHECK(S, DecodeSORegMemOperand(Inst, imm, Address, Decoder));
> >> +  CHECK(S, DecodePredicateOperand(Inst, pred, Address, Decoder));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD1LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2617,47 +2686,47 @@
> >>  unsigned index = 0;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 5, 3);
> >>      break;
> >>    case 1:
> >>      if (fieldFromInstruction32(Insn, 5, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 6, 2);
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >>        align = 2;
> >>      break;
> >>    case 2:
> >>      if (fieldFromInstruction32(Insn, 6, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 7, 1);
> >>      if (fieldFromInstruction32(Insn, 4, 2) != 0)
> >>        align = 4;
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST1LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2668,47 +2737,47 @@
> >>  unsigned index = 0;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 5, 3);
> >>      break;
> >>    case 1:
> >>      if (fieldFromInstruction32(Insn, 5, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 6, 2);
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >>        align = 2;
> >>      break;
> >>    case 2:
> >>      if (fieldFromInstruction32(Insn, 6, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 7, 1);
> >>      if (fieldFromInstruction32(Insn, 4, 2) != 0)
> >>        align = 4;
> >>  }
> >>
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD2LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2720,7 +2789,7 @@
> >>  unsigned inc = 1;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      index = fieldFromInstruction32(Insn, 5, 3);
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> @@ -2735,7 +2804,7 @@
> >>      break;
> >>    case 2:
> >>      if (fieldFromInstruction32(Insn, 5, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 7, 1);
> >>      if (fieldFromInstruction32(Insn, 4, 1) != 0)
> >>        align = 8;
> >> @@ -2744,28 +2813,28 @@
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST2LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2777,7 +2846,7 @@
> >>  unsigned inc = 1;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      index = fieldFromInstruction32(Insn, 5, 3);
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> @@ -2792,7 +2861,7 @@
> >>      break;
> >>    case 2:
> >>      if (fieldFromInstruction32(Insn, 5, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 7, 1);
> >>      if (fieldFromInstruction32(Insn, 4, 1) != 0)
> >>        align = 8;
> >> @@ -2802,26 +2871,26 @@
> >>  }
> >>
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD3LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2833,53 +2902,53 @@
> >>  unsigned inc = 1;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 5, 3);
> >>      break;
> >>    case 1:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 6, 2);
> >>      if (fieldFromInstruction32(Insn, 5, 1))
> >>        inc = 2;
> >>      break;
> >>    case 2:
> >>      if (fieldFromInstruction32(Insn, 4, 2))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 7, 1);
> >>      if (fieldFromInstruction32(Insn, 6, 1))
> >>        inc = 2;
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
> >>
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST3LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2891,22 +2960,22 @@
> >>  unsigned inc = 1;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 5, 3);
> >>      break;
> >>    case 1:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 6, 2);
> >>      if (fieldFromInstruction32(Insn, 5, 1))
> >>        inc = 2;
> >>      break;
> >>    case 2:
> >>      if (fieldFromInstruction32(Insn, 4, 2))
> >> -        return false; // UNDEFINED
> >> +        return Fail; // UNDEFINED
> >>      index = fieldFromInstruction32(Insn, 7, 1);
> >>      if (fieldFromInstruction32(Insn, 6, 1))
> >>        inc = 2;
> >> @@ -2914,27 +2983,27 @@
> >>  }
> >>
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> -static bool DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVLD4LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -2946,7 +3015,7 @@
> >>  unsigned inc = 1;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >>        align = 4;
> >> @@ -2968,33 +3037,33 @@
> >>      break;
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder));
> >>
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >> -static bool DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
> >> +static DecodeStatus DecodeVST4LN(llvm::MCInst &Inst, unsigned Insn,
> >>                         uint64_t Address, const void *Decoder) {
> >> +  DecodeStatus S = Success;
> >> +
> >>  unsigned Rn = fieldFromInstruction32(Insn, 16, 4);
> >>  unsigned Rm = fieldFromInstruction32(Insn, 0, 4);
> >>  unsigned Rd = fieldFromInstruction32(Insn, 12, 4);
> >> @@ -3006,7 +3075,7 @@
> >>  unsigned inc = 1;
> >>  switch (size) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case 0:
> >>      if (fieldFromInstruction32(Insn, 4, 1))
> >>        align = 4;
> >> @@ -3029,22 +3098,20 @@
> >>  }
> >>
> >>  if (Rm != 0xF) { // Writeback
> >> -    if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  }
> >> -  if (!DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(align));
> >>  if (Rm != 0xF && Rm != 0xD) {
> >> -    if (!DecodeGPRRegisterClass(Inst, Rm, Address, Decoder))
> >> -      return false;
> >> +    CHECK(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder));
> >>  }
> >>
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder)) return
> false;
> >> -  if (!DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder)) return
> false;
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+2*inc, Address, Decoder));
> >> +  CHECK(S, DecodeDPRRegisterClass(Inst, Rd+3*inc, Address, Decoder));
> >>  Inst.addOperand(MCOperand::CreateImm(index));
> >>
> >> -  return true;
> >> +  return S;
> >> }
> >>
> >>
> >> Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h?rev=137830
> &r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h (original)
> >> +++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h Wed Aug 17
> 12:44:15 2011
> >> @@ -40,11 +40,11 @@
> >>  }
> >>
> >>  /// getInstruction - See MCDisassembler.
> >> -  bool getInstruction(MCInst &instr,
> >> -                      uint64_t &size,
> >> -                      const MemoryObject &region,
> >> -                      uint64_t address,
> >> -                      raw_ostream &vStream) const;
> >> +  DecodeStatus getInstruction(MCInst &instr,
> >> +                              uint64_t &size,
> >> +                              const MemoryObject &region,
> >> +                              uint64_t address,
> >> +                              raw_ostream &vStream) const;
> >>
> >>  /// getEDInfo - See MCDisassembler.
> >>  EDInstInfo *getEDInfo() const;
> >> @@ -64,11 +64,11 @@
> >>  }
> >>
> >>  /// getInstruction - See MCDisassembler.
> >> -  bool getInstruction(MCInst &instr,
> >> -                      uint64_t &size,
> >> -                      const MemoryObject &region,
> >> -                      uint64_t address,
> >> -                      raw_ostream &vStream) const;
> >> +  DecodeStatus getInstruction(MCInst &instr,
> >> +                              uint64_t &size,
> >> +                              const MemoryObject &region,
> >> +                              uint64_t address,
> >> +                              raw_ostream &vStream) const;
> >>
> >>  /// getEDInfo - See MCDisassembler.
> >>  EDInstInfo *getEDInfo() const;
> >>
> >> Modified:
> llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.cpp
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.cpp?re
> v=137830&r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.cpp
> (original)
> >> +++ llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.cpp Wed
> Aug 17 12:44:15 2011
> >> @@ -493,7 +493,7 @@
> >> // Public interface for the disassembler
> >> //
> >>
> >> -bool MBlazeDisassembler::getInstruction(MCInst &instr,
> >> +MCDisassembler::DecodeStatus MBlazeDisassembler::getInstruction(MCInst
> &instr,
> >>                                        uint64_t &size,
> >>                                        const MemoryObject &region,
> >>                                        uint64_t address,
> >> @@ -508,7 +508,7 @@
> >>
> >>  // We want to read exactly 4 bytes of data.
> >>  if (region.readBytes(address, 4, (uint8_t*)bytes, &read) == -1 || read
> < 4)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  // Encoded as a big-endian 32-bit word in the stream.
> >>  insn = (bytes[0]<<24) | (bytes[1]<<16) | (bytes[2]<< 8) |
> (bytes[3]<<0);
> >> @@ -517,7 +517,7 @@
> >>  // that it is a valid instruction.
> >>  unsigned opcode = getOPCODE(insn);
> >>  if (opcode == UNSUPPORTED)
> >> -    return false;
> >> +    return Fail;
> >>
> >>  instr.setOpcode(opcode);
> >>
> >> @@ -529,11 +529,11 @@
> >>  uint64_t tsFlags = MBlazeInsts[opcode].TSFlags;
> >>  switch ((tsFlags & MBlazeII::FormMask)) {
> >>  default:
> >> -    return false;
> >> +    return Fail;
> >>
> >>  case MBlazeII::FRRRR:
> >>    if (RD == UNSUPPORTED || RA == UNSUPPORTED || RB == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RB));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >> @@ -541,7 +541,7 @@
> >>
> >>  case MBlazeII::FRRR:
> >>    if (RD == UNSUPPORTED || RA == UNSUPPORTED || RB == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    instr.addOperand(MCOperand::CreateReg(RB));
> >> @@ -550,23 +550,23 @@
> >>  case MBlazeII::FRI:
> >>    switch (opcode) {
> >>    default:
> >> -      return false;
> >> +      return Fail;
> >>    case MBlaze::MFS:
> >>      if (RD == UNSUPPORTED)
> >> -        return false;
> >> +        return Fail;
> >>      instr.addOperand(MCOperand::CreateReg(RD));
> >>      instr.addOperand(MCOperand::CreateImm(insn&0x3FFF));
> >>      break;
> >>    case MBlaze::MTS:
> >>      if (RA == UNSUPPORTED)
> >> -        return false;
> >> +        return Fail;
> >>      instr.addOperand(MCOperand::CreateImm(insn&0x3FFF));
> >>      instr.addOperand(MCOperand::CreateReg(RA));
> >>      break;
> >>    case MBlaze::MSRSET:
> >>    case MBlaze::MSRCLR:
> >>      if (RD == UNSUPPORTED)
> >> -        return false;
> >> +        return Fail;
> >>      instr.addOperand(MCOperand::CreateReg(RD));
> >>      instr.addOperand(MCOperand::CreateImm(insn&0x7FFF));
> >>      break;
> >> @@ -575,7 +575,7 @@
> >>
> >>  case MBlazeII::FRRI:
> >>    if (RD == UNSUPPORTED || RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    switch (opcode) {
> >> @@ -592,35 +592,35 @@
> >>
> >>  case MBlazeII::FCRR:
> >>    if (RA == UNSUPPORTED || RB == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    instr.addOperand(MCOperand::CreateReg(RB));
> >>    break;
> >>
> >>  case MBlazeII::FCRI:
> >>    if (RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    instr.addOperand(MCOperand::CreateImm(getIMM(insn)));
> >>    break;
> >>
> >>  case MBlazeII::FRCR:
> >>    if (RD == UNSUPPORTED || RB == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RB));
> >>    break;
> >>
> >>  case MBlazeII::FRCI:
> >>    if (RD == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateImm(getIMM(insn)));
> >>    break;
> >>
> >>  case MBlazeII::FCCR:
> >>    if (RB == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RB));
> >>    break;
> >>
> >> @@ -630,7 +630,7 @@
> >>
> >>  case MBlazeII::FRRCI:
> >>    if (RD == UNSUPPORTED || RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    instr.addOperand(MCOperand::CreateImm(getSHT(insn)));
> >> @@ -638,35 +638,35 @@
> >>
> >>  case MBlazeII::FRRC:
> >>    if (RD == UNSUPPORTED || RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    break;
> >>
> >>  case MBlazeII::FRCX:
> >>    if (RD == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateImm(getFSL(insn)));
> >>    break;
> >>
> >>  case MBlazeII::FRCS:
> >>    if (RD == UNSUPPORTED || RS == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateReg(RS));
> >>    break;
> >>
> >>  case MBlazeII::FCRCS:
> >>    if (RS == UNSUPPORTED || RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RS));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    break;
> >>
> >>  case MBlazeII::FCRCX:
> >>    if (RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >>    instr.addOperand(MCOperand::CreateImm(getFSL(insn)));
> >>    break;
> >> @@ -677,13 +677,13 @@
> >>
> >>  case MBlazeII::FCR:
> >>    if (RB == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RB));
> >>    break;
> >>
> >>  case MBlazeII::FRIR:
> >>    if (RD == UNSUPPORTED || RA == UNSUPPORTED)
> >> -      return false;
> >> +      return Fail;
> >>    instr.addOperand(MCOperand::CreateReg(RD));
> >>    instr.addOperand(MCOperand::CreateImm(getIMM(insn)));
> >>    instr.addOperand(MCOperand::CreateReg(RA));
> >> @@ -693,7 +693,7 @@
> >>  // We always consume 4 bytes of data on success
> >>  size = 4;
> >>
> >> -  return true;
> >> +  return Success;
> >> }
> >>
> >> static MCDisassembler *createMBlazeDisassembler(const Target &T) {
> >>
> >> Modified: llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.h
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.h?rev=
> 137830&r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.h
> (original)
> >> +++ llvm/trunk/lib/Target/MBlaze/Disassembler/MBlazeDisassembler.h Wed
> Aug 17 12:44:15 2011
> >> @@ -40,7 +40,7 @@
> >>  }
> >>
> >>  /// getInstruction - See MCDisassembler.
> >> -  bool getInstruction(MCInst &instr,
> >> +  MCDisassembler::DecodeStatus getInstruction(MCInst &instr,
> >>                      uint64_t &size,
> >>                      const MemoryObject &region,
> >>                      uint64_t address,
> >>
> >> Modified: llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.cpp
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.cpp?rev=1378
> 30&r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.cpp
> (original)
> >> +++ llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.cpp Wed Aug
> 17 12:44:15 2011
> >> @@ -106,11 +106,12 @@
> >> // Public interface for the disassembler
> >> //
> >>
> >> -bool X86GenericDisassembler::getInstruction(MCInst &instr,
> >> -                                            uint64_t &size,
> >> -                                            const MemoryObject &region,
> >> -                                            uint64_t address,
> >> -                                            raw_ostream &vStream) const
> {
> >> +MCDisassembler::DecodeStatus
> >> +X86GenericDisassembler::getInstruction(MCInst &instr,
> >> +                                       uint64_t &size,
> >> +                                       const MemoryObject &region,
> >> +                                       uint64_t address,
> >> +                                       raw_ostream &vStream) const {
> >>  InternalInstruction internalInstr;
> >>
> >>  int ret = decodeInstruction(&internalInstr,
> >> @@ -123,11 +124,11 @@
> >>
> >>  if (ret) {
> >>    size = internalInstr.readerCursor - address;
> >> -    return false;
> >> +    return Fail;
> >>  }
> >>  else {
> >>    size = internalInstr.length;
> >> -    return !translateInstruction(instr, internalInstr);
> >> +    return (!translateInstruction(instr, internalInstr)) ? Success :
> Fail;
> >>  }
> >> }
> >>
> >>
> >> Modified: llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.h
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.h?rev=137830
> &r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.h (original)
> >> +++ llvm/trunk/lib/Target/X86/Disassembler/X86Disassembler.h Wed Aug 17
> 12:44:15 2011
> >> @@ -112,11 +112,11 @@
> >>  ~X86GenericDisassembler();
> >>
> >>  /// getInstruction - See MCDisassembler.
> >> -  bool getInstruction(MCInst &instr,
> >> -                      uint64_t &size,
> >> -                      const MemoryObject &region,
> >> -                      uint64_t address,
> >> -                      raw_ostream &vStream) const;
> >> +  DecodeStatus getInstruction(MCInst &instr,
> >> +                              uint64_t &size,
> >> +                              const MemoryObject &region,
> >> +                              uint64_t address,
> >> +                              raw_ostream &vStream) const;
> >>
> >>  /// getEDInfo - See MCDisassembler.
> >>  EDInstInfo *getEDInfo() const;
> >>
> >> Modified: llvm/trunk/test/MC/Disassembler/ARM/invalid-LDRB_POST-arm.txt
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/test/MC/Disassembler/ARM/invalid-LDRB_POST-
> arm.txt?rev=137830&r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/test/MC/Disassembler/ARM/invalid-LDRB_POST-arm.txt
> (original)
> >> +++ llvm/trunk/test/MC/Disassembler/ARM/invalid-LDRB_POST-arm.txt Wed
> Aug 17 12:44:15 2011
> >> @@ -1,4 +1,4 @@
> >> -# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep
> {invalid instruction encoding}
> >> +# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep
> {potentially undefined instruction encoding}
> >>
> >> # Opcode=140 Name=LDRB_POST Format=ARM_FORMAT_LDFRM(6)
> >> #  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9
> 8  7  6  5  4  3  2  1  0
> >>
> >> Modified: llvm/trunk/tools/llvm-mc/Disassembler.cpp
> >> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-
> mc/Disassembler.cpp?rev=137830&r1=137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/tools/llvm-mc/Disassembler.cpp (original)
> >> +++ llvm/trunk/tools/llvm-mc/Disassembler.cpp Wed Aug 17 12:44:15 2011
> >> @@ -65,15 +65,26 @@
> >>  for (Index = 0; Index < Bytes.size(); Index += Size) {
> >>    MCInst Inst;
> >>
> >> -    if (DisAsm.getInstruction(Inst, Size, memoryObject, Index,
> >> -                               /*REMOVE*/ nulls())) {
> >> -      Printer.printInst(&Inst, Out);
> >> -      Out << "\n";
> >> -    } else {
> >> +    MCDisassembler::DecodeStatus S;
> >> +    S = DisAsm.getInstruction(Inst, Size, memoryObject, Index,
> >> +                              /*REMOVE*/ nulls());
> >> +    switch (S) {
> >
> >
> > Changing this to a switch statement is good. The C bindings in
> MCDisasembler.cpp and EDDisassembler.cpp need to be changed, too, though.
> They're still doing "!Disasm->getInstruction()" type constructs.
> >
> >
> >> +    case MCDisassembler::Fail:
> >>      SM.PrintMessage(SMLoc::getFromPointer(Bytes[Index].second),
> >>                      "invalid instruction encoding", "warning");
> >>      if (Size == 0)
> >>        Size = 1; // skip illegible bytes
> >> +      break;
> >> +
> >> +    case MCDisassembler::SoftFail:
> >> +      SM.PrintMessage(SMLoc::getFromPointer(Bytes[Index].second),
> >> +                      "potentially undefined instruction encoding",
> "warning");
> >> +      // Fall through
> >> +
> >> +    case MCDisassembler::Success:
> >> +      Printer.printInst(&Inst, Out);
> >> +      Out << "\n";
> >> +      break;
> >>    }
> >>  }
> >>
> >>
> >> Modified: llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp?rev=137830&r1=137
> 829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp (original)
> >> +++ llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp Wed Aug 17
> 12:44:15 2011
> >> @@ -128,5 +128,15 @@
> >>    return;
> >>  }
> >>
> >> +  // ARM and Thumb have a CHECK() macro to deal with DecodeStatuses.
> >> +  if (Target.getName() == "ARM" ||
> >> +      Target.getName() == "Thumb") {
> >> +    FixedLenDecoderEmitter(Records,
> >> +                           "CHECK(S, ", ");",
> >> +                           "S", "Fail",
> >> +                           "DecodeStatus S =
> Success;\n(void)S;").run(OS);
> >> +    return;
> >> +  }
> >> +
> >>  FixedLenDecoderEmitter(Records).run(OS);
> >> }
> >>
> >> Modified: llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.cpp
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.cpp?rev=137830&r1=
> 137829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.cpp (original)
> >> +++ llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.cpp Wed Aug 17
> 12:44:15 2011
> >> @@ -238,19 +238,24 @@
> >>  // Width of instructions
> >>  unsigned BitWidth;
> >>
> >> +  // Parent emitter
> >> +  const FixedLenDecoderEmitter *Emitter;
> >> +
> >> public:
> >>  FilterChooser(const FilterChooser &FC) :
> >>    AllInstructions(FC.AllInstructions), Opcodes(FC.Opcodes),
> >>      Operands(FC.Operands), Filters(FC.Filters),
> >>      FilterBitValues(FC.FilterBitValues), Parent(FC.Parent),
> >> -      BestIndex(FC.BestIndex), BitWidth(FC.BitWidth) { }
> >> +    BestIndex(FC.BestIndex), BitWidth(FC.BitWidth),
> >> +    Emitter(FC.Emitter) { }
> >>
> >>  FilterChooser(const std::vector<const CodeGenInstruction*> &Insts,
> >>                const std::vector<unsigned> &IDs,
> >>    std::map<unsigned, std::vector<OperandInfo> > &Ops,
> >> -                unsigned BW) :
> >> +                unsigned BW,
> >> +                const FixedLenDecoderEmitter *E) :
> >>      AllInstructions(Insts), Opcodes(IDs), Operands(Ops), Filters(),
> >> -      Parent(NULL), BestIndex(-1), BitWidth(BW) {
> >> +      Parent(NULL), BestIndex(-1), BitWidth(BW), Emitter(E) {
> >>    for (unsigned i = 0; i < BitWidth; ++i)
> >>      FilterBitValues.push_back(BIT_UNFILTERED);
> >>
> >> @@ -264,7 +269,8 @@
> >>                FilterChooser &parent) :
> >>      AllInstructions(Insts), Opcodes(IDs), Operands(Ops),
> >>      Filters(), FilterBitValues(ParentFilterBitValues),
> >> -      Parent(&parent), BestIndex(-1), BitWidth(parent.BitWidth) {
> >> +      Parent(&parent), BestIndex(-1), BitWidth(parent.BitWidth),
> >> +      Emitter(parent.Emitter) {
> >>    doFilter();
> >>  }
> >>
> >> @@ -563,17 +569,17 @@
> >> void FilterChooser::emitTop(raw_ostream &o, unsigned Indentation,
> >>                            std::string Namespace) {
> >>  o.indent(Indentation) <<
> >> -    "static bool decode" << Namespace << "Instruction" << BitWidth
> >> +    "static MCDisassembler::DecodeStatus decode" << Namespace <<
> "Instruction" << BitWidth
> >>    << "(MCInst &MI, uint" << BitWidth << "_t insn, uint64_t Address, "
> >>    << "const void *Decoder) {\n";
> >> -  o.indent(Indentation) << "  unsigned tmp = 0;\n  (void)tmp;\n";
> >> +  o.indent(Indentation) << "  unsigned tmp = 0;\n  (void)tmp;\n" <<
> Emitter->Locals << "\n";
> >>
> >>  ++Indentation; ++Indentation;
> >>  // Emits code to decode the instructions.
> >>  emit(o, Indentation);
> >>
> >>  o << '\n';
> >> -  o.indent(Indentation) << "return false;\n";
> >> +  o.indent(Indentation) << "return " << Emitter->ReturnFail << ";\n";
> >>  --Indentation; --Indentation;
> >>
> >>  o.indent(Indentation) << "}\n";
> >> @@ -744,8 +750,8 @@
> >>  }
> >>
> >>  if (Decoder != "")
> >> -    o.indent(Indentation) << "  if (!" << Decoder
> >> -                          << "(MI, tmp, Address, Decoder)) return
> false;\n";
> >> +    o.indent(Indentation) << "  " << Emitter->GuardPrefix << Decoder
> >> +                          << "(MI, tmp, Address, Decoder)" << Emitter-
> >GuardPostfix << "\n";
> >>  else
> >>    o.indent(Indentation) << "
> MI.addOperand(MCOperand::CreateImm(tmp));\n";
> >>
> >> @@ -776,15 +782,15 @@
> >>         I = InsnOperands.begin(), E = InsnOperands.end(); I != E; ++I) {
> >>      // If a custom instruction decoder was specified, use that.
> >>      if (I->numFields() == 0 && I->Decoder.size()) {
> >> -        o.indent(Indentation) << "  if (!" << I->Decoder
> >> -                              << "(MI, insn, Address, Decoder)) return
> false;\n";
> >> +        o.indent(Indentation) << "  " << Emitter->GuardPrefix << I-
> >Decoder
> >> +                              << "(MI, insn, Address, Decoder)" <<
> Emitter->GuardPostfix << "\n";
> >>        break;
> >>      }
> >>
> >>      emitBinaryParser(o, Indentation, *I);
> >>    }
> >>
> >> -    o.indent(Indentation) << "  return true; // " << nameWithID(Opc)
> >> +    o.indent(Indentation) << "  return " << Emitter->ReturnOK << "; //
> " << nameWithID(Opc)
> >>                          << '\n';
> >>    o.indent(Indentation) << "}\n";
> >>    return true;
> >> @@ -821,14 +827,14 @@
> >>       I = InsnOperands.begin(), E = InsnOperands.end(); I != E; ++I) {
> >>    // If a custom instruction decoder was specified, use that.
> >>    if (I->numFields() == 0 && I->Decoder.size()) {
> >> -      o.indent(Indentation) << "  if (!" << I->Decoder
> >> -                            << "(MI, insn, Address, Decoder)) return
> false;\n";
> >> +      o.indent(Indentation) << "  " << Emitter->GuardPrefix << I-
> >Decoder
> >> +                            << "(MI, insn, Address, Decoder)" <<
> Emitter->GuardPostfix << "\n";
> >>      break;
> >>    }
> >>
> >>    emitBinaryParser(o, Indentation, *I);
> >>  }
> >> -  o.indent(Indentation) << "  return true; // " << nameWithID(Opc)
> >> +  o.indent(Indentation) << "  return " << Emitter->ReturnOK << "; // "
> << nameWithID(Opc)
> >>                        << '\n';
> >>  o.indent(Indentation) << "}\n";
> >>
> >> @@ -1426,7 +1432,7 @@
> >>
> >>    // Emit the decoder for this namespace+width combination.
> >>    FilterChooser FC(NumberedInstructions, I->second, Operands,
> >> -                     8*I->first.second);
> >> +                     8*I->first.second, this);
> >>    FC.emitTop(o, 0, I->first.first);
> >>  }
> >>
> >>
> >> Modified: llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.h
> >> URL: http://llvm.org/viewvc/llvm-
> project/llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.h?rev=137830&r1=13
> 7829&r2=137830&view=diff
> >>
> ===========================================================================
> ===
> >> --- llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.h (original)
> >> +++ llvm/trunk/utils/TableGen/FixedLenDecoderEmitter.h Wed Aug 17
> 12:44:15 2011
> >> @@ -49,9 +49,16 @@
> >>
> >> class FixedLenDecoderEmitter : public TableGenBackend {
> >> public:
> >> -  FixedLenDecoderEmitter(RecordKeeper &R) :
> >> +  FixedLenDecoderEmitter(RecordKeeper &R,
> >> +                         std::string GPrefix  = "if (",
> >> +                         std::string GPostfix = " ==
> MCDisassembler::Fail) return MCDisassembler::Fail;",
> >> +                         std::string ROK      =
> "MCDisassembler::Success",
> >> +                         std::string RFail    = "MCDisassembler::Fail",
> >> +                         std::string L        = "") :
> >>    Records(R), Target(R),
> >> -    NumberedInstructions(Target.getInstructionsByEnumValue()) {}
> >> +    NumberedInstructions(Target.getInstructionsByEnumValue()),
> >> +    GuardPrefix(GPrefix), GuardPostfix(GPostfix),
> >> +    ReturnOK(ROK), ReturnFail(RFail), Locals(L) {}
> >>
> >>  // run - Output the code emitter
> >>  void run(raw_ostream &o);
> >> @@ -62,7 +69,10 @@
> >>  std::vector<const CodeGenInstruction*> NumberedInstructions;
> >>  std::vector<unsigned> Opcodes;
> >>  std::map<unsigned, std::vector<OperandInfo> > Operands;
> >> -
> >> +public:
> >> +  std::string GuardPrefix, GuardPostfix;
> >> +  std::string ReturnOK, ReturnFail;
> >> +  std::string Locals;
> >> };
> >>
> >> } // end llvm namespace
> >>
> >>
> >> _______________________________________________
> >> llvm-commits mailing list
> >> llvm-commits at cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >
> 
> 






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