utils/TableGen/CodeGenInstruction.cpp - platform/external/llvm - Git at Google

 //===- CodeGenInstruction.cpp - CodeGen Instruction Class Wrapper ---------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the CodeGenInstruction class.
 //
 //===----------------------------------------------------------------------===//

 #include "CodeGenInstruction.h"
 #include "CodeGenTarget.h"
 #include "Record.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/STLExtras.h"
 #include <set>
 using namespace llvm;

 //===----------------------------------------------------------------------===//
 // CGIOperandList Implementation
 //===----------------------------------------------------------------------===//

 CGIOperandList::CGIOperandList(Record *R) : TheDef(R) {
   isPredicable = false;
   hasOptionalDef = false;
   isVariadic = false;

   DagInit *OutDI = R->getValueAsDag("OutOperandList");

   if (DefInit *Init = dynamic_cast<DefInit*>(OutDI->getOperator())) {
     if (Init->getDef()->getName() != "outs")
       throw R->getName() + ": invalid def name for output list: use 'outs'";
   } else
     throw R->getName() + ": invalid output list: use 'outs'";

   NumDefs = OutDI->getNumArgs();

   DagInit *InDI = R->getValueAsDag("InOperandList");
   if (DefInit *Init = dynamic_cast<DefInit*>(InDI->getOperator())) {
     if (Init->getDef()->getName() != "ins")
       throw R->getName() + ": invalid def name for input list: use 'ins'";
   } else
     throw R->getName() + ": invalid input list: use 'ins'";

   unsigned MIOperandNo = 0;
   std::set<std::string> OperandNames;
   for (unsigned i = 0, e = InDI->getNumArgs()+OutDI->getNumArgs(); i != e; ++i){
     Init *ArgInit;
     std::string ArgName;
     if (i < NumDefs) {
       ArgInit = OutDI->getArg(i);
       ArgName = OutDI->getArgName(i);
     } else {
       ArgInit = InDI->getArg(i-NumDefs);
       ArgName = InDI->getArgName(i-NumDefs);
     }

     DefInit *Arg = dynamic_cast<DefInit*>(ArgInit);
     if (!Arg)
       throw "Illegal operand for the '" + R->getName() + "' instruction!";

     Record *Rec = Arg->getDef();
     std::string PrintMethod = "printOperand";
     std::string EncoderMethod;
     unsigned NumOps = 1;
     DagInit *MIOpInfo = 0;
     if (Rec->isSubClassOf("Operand")) {
       PrintMethod = Rec->getValueAsString("PrintMethod");
       // If there is an explicit encoder method, use it.
       EncoderMethod = Rec->getValueAsString("EncoderMethod");
       MIOpInfo = Rec->getValueAsDag("MIOperandInfo");

       // Verify that MIOpInfo has an 'ops' root value.
       if (!dynamic_cast<DefInit*>(MIOpInfo->getOperator()) ||
           dynamic_cast<DefInit*>(MIOpInfo->getOperator())
           ->getDef()->getName() != "ops")
         throw "Bad value for MIOperandInfo in operand '" + Rec->getName() +
         "'\n";

       // If we have MIOpInfo, then we have #operands equal to number of entries
       // in MIOperandInfo.
       if (unsigned NumArgs = MIOpInfo->getNumArgs())
         NumOps = NumArgs;

       if (Rec->isSubClassOf("PredicateOperand"))
         isPredicable = true;
       else if (Rec->isSubClassOf("OptionalDefOperand"))
         hasOptionalDef = true;
     } else if (Rec->getName() == "variable_ops") {
       isVariadic = true;
       continue;
     } else if (!Rec->isSubClassOf("RegisterClass") &&
                Rec->getName() != "ptr_rc" && Rec->getName() != "unknown")
       throw "Unknown operand class '" + Rec->getName() +
       "' in '" + R->getName() + "' instruction!";

     // Check that the operand has a name and that it's unique.
     if (ArgName.empty())
       throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
       " has no name!";
     if (!OperandNames.insert(ArgName).second)
       throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
       " has the same name as a previous operand!";

     OperandList.push_back(OperandInfo(Rec, ArgName, PrintMethod, EncoderMethod,
                                       MIOperandNo, NumOps, MIOpInfo));
     MIOperandNo += NumOps;
   }


   // Make sure the constraints list for each operand is large enough to hold
   // constraint info, even if none is present.
   for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
     OperandList[i].Constraints.resize(OperandList[i].MINumOperands);
 }


 /// getOperandNamed - Return the index of the operand with the specified
 /// non-empty name.  If the instruction does not have an operand with the
 /// specified name, throw an exception.
 ///
 unsigned CGIOperandList::getOperandNamed(StringRef Name) const {
   unsigned OpIdx;
   if (hasOperandNamed(Name, OpIdx)) return OpIdx;
   throw "'" + TheDef->getName() + "' does not have an operand named '$" +
     Name.str() + "'!";
 }

 /// hasOperandNamed - Query whether the instruction has an operand of the
 /// given name. If so, return true and set OpIdx to the index of the
 /// operand. Otherwise, return false.
 bool CGIOperandList::hasOperandNamed(StringRef Name, unsigned &OpIdx) const {
   assert(!Name.empty() && "Cannot search for operand with no name!");
   for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
     if (OperandList[i].Name == Name) {
       OpIdx = i;
       return true;
     }
   return false;
 }

 std::pair<unsigned,unsigned>
 CGIOperandList::ParseOperandName(const std::string &Op, bool AllowWholeOp) {
   if (Op.empty() || Op[0] != '$')
     throw TheDef->getName() + ": Illegal operand name: '" + Op + "'";

   std::string OpName = Op.substr(1);
   std::string SubOpName;

   // Check to see if this is $foo.bar.
   std::string::size_type DotIdx = OpName.find_first_of(".");
   if (DotIdx != std::string::npos) {
     SubOpName = OpName.substr(DotIdx+1);
     if (SubOpName.empty())
       throw TheDef->getName() + ": illegal empty suboperand name in '" +Op +"'";
     OpName = OpName.substr(0, DotIdx);
   }

   unsigned OpIdx = getOperandNamed(OpName);

   if (SubOpName.empty()) {  // If no suboperand name was specified:
     // If one was needed, throw.
     if (OperandList[OpIdx].MINumOperands > 1 && !AllowWholeOp &&
         SubOpName.empty())
       throw TheDef->getName() + ": Illegal to refer to"
       " whole operand part of complex operand '" + Op + "'";

     // Otherwise, return the operand.
     return std::make_pair(OpIdx, 0U);
   }

   // Find the suboperand number involved.
   DagInit *MIOpInfo = OperandList[OpIdx].MIOperandInfo;
   if (MIOpInfo == 0)
     throw TheDef->getName() + ": unknown suboperand name in '" + Op + "'";

   // Find the operand with the right name.
   for (unsigned i = 0, e = MIOpInfo->getNumArgs(); i != e; ++i)
     if (MIOpInfo->getArgName(i) == SubOpName)
       return std::make_pair(OpIdx, i);

   // Otherwise, didn't find it!
   throw TheDef->getName() + ": unknown suboperand name in '" + Op + "'";
 }

 static void ParseConstraint(const std::string &CStr, CGIOperandList &Ops) {
   // EARLY_CLOBBER: @early $reg
   std::string::size_type wpos = CStr.find_first_of(" \t");
   std::string::size_type start = CStr.find_first_not_of(" \t");
   std::string Tok = CStr.substr(start, wpos - start);
   if (Tok == "@earlyclobber") {
     std::string Name = CStr.substr(wpos+1);
     wpos = Name.find_first_not_of(" \t");
     if (wpos == std::string::npos)
       throw "Illegal format for @earlyclobber constraint: '" + CStr + "'";
     Name = Name.substr(wpos);
     std::pair<unsigned,unsigned> Op = Ops.ParseOperandName(Name, false);

     // Build the string for the operand
     if (!Ops[Op.first].Constraints[Op.second].isNone())
       throw "Operand '" + Name + "' cannot have multiple constraints!";
     Ops[Op.first].Constraints[Op.second] =
     CGIOperandList::ConstraintInfo::getEarlyClobber();
     return;
   }

   // Only other constraint is "TIED_TO" for now.
   std::string::size_type pos = CStr.find_first_of('=');
   assert(pos != std::string::npos && "Unrecognized constraint");
   start = CStr.find_first_not_of(" \t");
   std::string Name = CStr.substr(start, pos - start);

   // TIED_TO: $src1 = $dst
   wpos = Name.find_first_of(" \t");
   if (wpos == std::string::npos)
     throw "Illegal format for tied-to constraint: '" + CStr + "'";
   std::string DestOpName = Name.substr(0, wpos);
   std::pair<unsigned,unsigned> DestOp = Ops.ParseOperandName(DestOpName, false);

   Name = CStr.substr(pos+1);
   wpos = Name.find_first_not_of(" \t");
   if (wpos == std::string::npos)
     throw "Illegal format for tied-to constraint: '" + CStr + "'";

   std::pair<unsigned,unsigned> SrcOp =
   Ops.ParseOperandName(Name.substr(wpos), false);
   if (SrcOp > DestOp)
     throw "Illegal tied-to operand constraint '" + CStr + "'";


   unsigned FlatOpNo = Ops.getFlattenedOperandNumber(SrcOp);

   if (!Ops[DestOp.first].Constraints[DestOp.second].isNone())
     throw "Operand '" + DestOpName + "' cannot have multiple constraints!";
   Ops[DestOp.first].Constraints[DestOp.second] =
   CGIOperandList::ConstraintInfo::getTied(FlatOpNo);
 }

 static void ParseConstraints(const std::string &CStr, CGIOperandList &Ops) {
   if (CStr.empty()) return;

   const std::string delims(",");
   std::string::size_type bidx, eidx;

   bidx = CStr.find_first_not_of(delims);
   while (bidx != std::string::npos) {
     eidx = CStr.find_first_of(delims, bidx);
     if (eidx == std::string::npos)
       eidx = CStr.length();

     ParseConstraint(CStr.substr(bidx, eidx - bidx), Ops);
     bidx = CStr.find_first_not_of(delims, eidx);
   }
 }

 void CGIOperandList::ProcessDisableEncoding(std::string DisableEncoding) {
   while (1) {
     std::string OpName;
     tie(OpName, DisableEncoding) = getToken(DisableEncoding, " ,\t");
     if (OpName.empty()) break;

     // Figure out which operand this is.
     std::pair<unsigned,unsigned> Op = ParseOperandName(OpName, false);

     // Mark the operand as not-to-be encoded.
     if (Op.second >= OperandList[Op.first].DoNotEncode.size())
       OperandList[Op.first].DoNotEncode.resize(Op.second+1);
     OperandList[Op.first].DoNotEncode[Op.second] = true;
   }

 }

 //===----------------------------------------------------------------------===//
 // CodeGenInstruction Implementation
 //===----------------------------------------------------------------------===//

 CodeGenInstruction::CodeGenInstruction(Record *R) : TheDef(R), Operands(R) {
   Namespace = R->getValueAsString("Namespace");
   AsmString = R->getValueAsString("AsmString");

   isReturn     = R->getValueAsBit("isReturn");
   isBranch     = R->getValueAsBit("isBranch");
   isIndirectBranch = R->getValueAsBit("isIndirectBranch");
   isCompare    = R->getValueAsBit("isCompare");
   isMoveImm    = R->getValueAsBit("isMoveImm");
   isBarrier    = R->getValueAsBit("isBarrier");
   isCall       = R->getValueAsBit("isCall");
   canFoldAsLoad = R->getValueAsBit("canFoldAsLoad");
   mayLoad      = R->getValueAsBit("mayLoad");
   mayStore     = R->getValueAsBit("mayStore");
   isPredicable = Operands.isPredicable || R->getValueAsBit("isPredicable");
   isConvertibleToThreeAddress = R->getValueAsBit("isConvertibleToThreeAddress");
   isCommutable = R->getValueAsBit("isCommutable");
   isTerminator = R->getValueAsBit("isTerminator");
   isReMaterializable = R->getValueAsBit("isReMaterializable");
   hasDelaySlot = R->getValueAsBit("hasDelaySlot");
   usesCustomInserter = R->getValueAsBit("usesCustomInserter");
   hasCtrlDep   = R->getValueAsBit("hasCtrlDep");
   isNotDuplicable = R->getValueAsBit("isNotDuplicable");
   hasSideEffects = R->getValueAsBit("hasSideEffects");
   neverHasSideEffects = R->getValueAsBit("neverHasSideEffects");
   isAsCheapAsAMove = R->getValueAsBit("isAsCheapAsAMove");
   hasExtraSrcRegAllocReq = R->getValueAsBit("hasExtraSrcRegAllocReq");
   hasExtraDefRegAllocReq = R->getValueAsBit("hasExtraDefRegAllocReq");
   ImplicitDefs = R->getValueAsListOfDefs("Defs");
   ImplicitUses = R->getValueAsListOfDefs("Uses");

   if (neverHasSideEffects + hasSideEffects > 1)
     throw R->getName() + ": multiple conflicting side-effect flags set!";

   // Parse Constraints.
   ParseConstraints(R->getValueAsString("Constraints"), Operands);

   // Parse the DisableEncoding field.
   Operands.ProcessDisableEncoding(R->getValueAsString("DisableEncoding"));
 }

 /// HasOneImplicitDefWithKnownVT - If the instruction has at least one
 /// implicit def and it has a known VT, return the VT, otherwise return
 /// MVT::Other.
 MVT::SimpleValueType CodeGenInstruction::
 HasOneImplicitDefWithKnownVT(const CodeGenTarget &TargetInfo) const {
   if (ImplicitDefs.empty()) return MVT::Other;

   // Check to see if the first implicit def has a resolvable type.
   Record *FirstImplicitDef = ImplicitDefs[0];
   assert(FirstImplicitDef->isSubClassOf("Register"));
   const std::vector<MVT::SimpleValueType> &RegVTs =
     TargetInfo.getRegisterVTs(FirstImplicitDef);
   if (RegVTs.size() == 1)
     return RegVTs[0];
   return MVT::Other;
 }


 /// FlattenAsmStringVariants - Flatten the specified AsmString to only
 /// include text from the specified variant, returning the new string.
 std::string CodeGenInstruction::
 FlattenAsmStringVariants(StringRef Cur, unsigned Variant) {
   std::string Res = "";

   for (;;) {
     // Find the start of the next variant string.
     size_t VariantsStart = 0;
     for (size_t e = Cur.size(); VariantsStart != e; ++VariantsStart)
       if (Cur[VariantsStart] == '{' &&
           (VariantsStart == 0 || (Cur[VariantsStart-1] != '$' &&
                                   Cur[VariantsStart-1] != '\\')))
         break;

     // Add the prefix to the result.
     Res += Cur.slice(0, VariantsStart);
     if (VariantsStart == Cur.size())
       break;

     ++VariantsStart; // Skip the '{'.

     // Scan to the end of the variants string.
     size_t VariantsEnd = VariantsStart;
     unsigned NestedBraces = 1;
     for (size_t e = Cur.size(); VariantsEnd != e; ++VariantsEnd) {
       if (Cur[VariantsEnd] == '}' && Cur[VariantsEnd-1] != '\\') {
         if (--NestedBraces == 0)
           break;
       } else if (Cur[VariantsEnd] == '{')
         ++NestedBraces;
     }

     // Select the Nth variant (or empty).
     StringRef Selection = Cur.slice(VariantsStart, VariantsEnd);
     for (unsigned i = 0; i != Variant; ++i)
       Selection = Selection.split('|').second;
     Res += Selection.split('|').first;

     assert(VariantsEnd != Cur.size() &&
            "Unterminated variants in assembly string!");
     Cur = Cur.substr(VariantsEnd + 1);
   }

   return Res;
 }


 //===----------------------------------------------------------------------===//
 /// CodeGenInstAlias Implementation
 //===----------------------------------------------------------------------===//

 CodeGenInstAlias::CodeGenInstAlias(Record *R, CodeGenTarget &T) : TheDef(R) {
   AsmString = R->getValueAsString("AsmString");
   Result = R->getValueAsDag("ResultInst");

   // Verify that the root of the result is an instruction.
   DefInit *DI = dynamic_cast<DefInit*>(Result->getOperator());
   if (DI == 0 || !DI->getDef()->isSubClassOf("Instruction"))
     throw TGError(R->getLoc(), "result of inst alias should be an instruction");

   ResultInst = &T.getInstruction(DI->getDef());

   // NameClass - If argument names are repeated, we need to verify they have
   // the same class.
   StringMap<Record*> NameClass;

   // Decode and validate the arguments of the result.
   unsigned AliasOpNo = 0;
   for (unsigned i = 0, e = ResultInst->Operands.size(); i != e; ++i) {
     // Tied registers don't have an entry in the result dag.
     if (ResultInst->Operands[i].getTiedRegister() != -1)
       continue;

     if (AliasOpNo >= Result->getNumArgs())
       throw TGError(R->getLoc(), "result has " + utostr(Result->getNumArgs()) +
                     " arguments, but " + ResultInst->TheDef->getName() +
                     " instruction expects " +
                     utostr(ResultInst->Operands.size()) + " operands!");


     Init *Arg = Result->getArg(AliasOpNo);
     Record *ResultOpRec = ResultInst->Operands[i].Rec;

     // Handle explicit registers.
     if (DefInit *ADI = dynamic_cast<DefInit*>(Arg)) {
       if (ADI->getDef()->isSubClassOf("Register")) {
         if (!Result->getArgName(AliasOpNo).empty())
           throw TGError(R->getLoc(), "result fixed register argument must "
                         "not have a name!");

         if (!ResultOpRec->isSubClassOf("RegisterClass"))
           throw TGError(R->getLoc(), "result fixed register argument is not "
                         "passed to a RegisterClass operand!");

         if (!T.getRegisterClass(ResultOpRec).containsRegister(ADI->getDef()))
           throw TGError(R->getLoc(), "fixed register " +ADI->getDef()->getName()
                         + " is not a member of the " + ResultOpRec->getName() +
                         " register class!");

         // Now that it is validated, add it.
         ResultOperands.push_back(ResultOperand(ADI->getDef()));
         ++AliasOpNo;
         continue;
       }
       if (ADI->getDef()->getName() == "zero_reg") {
         if (!Result->getArgName(AliasOpNo).empty())
           throw TGError(R->getLoc(), "result fixed register argument must "
                         "not have a name!");

         // Check if this is an optional def.
         if (!ResultOpRec->isSubClassOf("OptionalDefOperand"))
           throw TGError(R->getLoc(), "reg0 used for result that is not an "
                         "OptionalDefOperand!");

         // Now that it is validated, add it.
         ResultOperands.push_back(ResultOperand(static_cast<Record*>(0)));
         ++AliasOpNo;
         continue;
       }
     }

     // If the operand is a record, it must have a name, and the record type must
     // match up with the instruction's argument type.
     if (DefInit *ADI = dynamic_cast<DefInit*>(Arg)) {
       if (Result->getArgName(AliasOpNo).empty())
         throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
                       " must have a name!");

       if (ADI->getDef() != ResultOpRec)
         throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
                       " declared with class " + ADI->getDef()->getName() +
                       ", instruction operand is class " +
                       ResultOpRec->getName());

       // Verify we don't have something like: (someinst GR16:$foo, GR32:$foo)
       // $foo can exist multiple times in the result list, but it must have the
       // same type.
       Record *&Entry = NameClass[Result->getArgName(AliasOpNo)];
       if (Entry && Entry != ADI->getDef())
         throw TGError(R->getLoc(), "result value $" +
                       Result->getArgName(AliasOpNo) +
                       " is both " + Entry->getName() + " and " +
                       ADI->getDef()->getName() + "!");

       // Now that it is validated, add it.
       ResultOperands.push_back(ResultOperand(Result->getArgName(AliasOpNo),
                                              ADI->getDef()));
       ++AliasOpNo;
       continue;
     }

     if (IntInit *II = dynamic_cast<IntInit*>(Arg)) {
       // Integer arguments can't have names.
       if (!Result->getArgName(AliasOpNo).empty())
         throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
                       " must not have a name!");
       if (ResultInst->Operands[i].MINumOperands != 1 ||
           !ResultOpRec->isSubClassOf("Operand"))
         throw TGError(R->getLoc(), "invalid argument class " +
                       ResultOpRec->getName() +
                       " for integer result operand!");
       ResultOperands.push_back(ResultOperand(II->getValue()));
       ++AliasOpNo;
       continue;
     }

     throw TGError(R->getLoc(), "result of inst alias has unknown operand type");
   }

   if (AliasOpNo != Result->getNumArgs())
     throw TGError(R->getLoc(), "result has " + utostr(Result->getNumArgs()) +
                   " arguments, but " + ResultInst->TheDef->getName() +
                   " instruction expects " + utostr(ResultInst->Operands.size())+
                   " operands!");
 }

 /// getResultInstOperandIndexForResultOperandIndex - Given an index into the
 /// ResultOperands array, translate it to a valid index in ResultInst's
 /// operand list.
 unsigned CodeGenInstAlias::
 getResultInstOperandIndexForResultOperandIndex(unsigned OpNo) const {
   unsigned OpIdx = 0;

   for (unsigned i = 0;; ++i) {
     assert(i != ResultInst->Operands.size() && "Didn't find entry");
     if (ResultInst->Operands[i].getTiedRegister() != -1)
       continue;

     if (OpIdx == OpNo) return i;

     ++OpIdx;
   }
 }
	//===- CodeGenInstruction.cpp - CodeGen Instruction Class Wrapper ---------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the CodeGenInstruction class.
	//
	//===----------------------------------------------------------------------===//

	#include "CodeGenInstruction.h"
	#include "CodeGenTarget.h"
	#include "Record.h"
	#include "llvm/ADT/StringExtras.h"
	#include "llvm/ADT/StringMap.h"
	#include "llvm/ADT/STLExtras.h"
	#include <set>
	using namespace llvm;

	//===----------------------------------------------------------------------===//
	// CGIOperandList Implementation
	//===----------------------------------------------------------------------===//

	CGIOperandList::CGIOperandList(Record *R) : TheDef(R) {
	isPredicable = false;
	hasOptionalDef = false;
	isVariadic = false;

	DagInit *OutDI = R->getValueAsDag("OutOperandList");

	if (DefInit Init = dynamic_cast<DefInit>(OutDI->getOperator())) {
	if (Init->getDef()->getName() != "outs")
	throw R->getName() + ": invalid def name for output list: use 'outs'";
	} else
	throw R->getName() + ": invalid output list: use 'outs'";

	NumDefs = OutDI->getNumArgs();

	DagInit *InDI = R->getValueAsDag("InOperandList");
	if (DefInit Init = dynamic_cast<DefInit>(InDI->getOperator())) {
	if (Init->getDef()->getName() != "ins")
	throw R->getName() + ": invalid def name for input list: use 'ins'";
	} else
	throw R->getName() + ": invalid input list: use 'ins'";

	unsigned MIOperandNo = 0;
	std::set<std::string> OperandNames;
	for (unsigned i = 0, e = InDI->getNumArgs()+OutDI->getNumArgs(); i != e; ++i){
	Init *ArgInit;
	std::string ArgName;
	if (i < NumDefs) {
	ArgInit = OutDI->getArg(i);
	ArgName = OutDI->getArgName(i);
	} else {
	ArgInit = InDI->getArg(i-NumDefs);
	ArgName = InDI->getArgName(i-NumDefs);
	}

	DefInit Arg = dynamic_cast<DefInit>(ArgInit);
	if (!Arg)
	throw "Illegal operand for the '" + R->getName() + "' instruction!";

	Record *Rec = Arg->getDef();
	std::string PrintMethod = "printOperand";
	std::string EncoderMethod;
	unsigned NumOps = 1;
	DagInit *MIOpInfo = 0;
	if (Rec->isSubClassOf("Operand")) {
	PrintMethod = Rec->getValueAsString("PrintMethod");
	// If there is an explicit encoder method, use it.
	EncoderMethod = Rec->getValueAsString("EncoderMethod");
	MIOpInfo = Rec->getValueAsDag("MIOperandInfo");

	// Verify that MIOpInfo has an 'ops' root value.
	if (!dynamic_cast<DefInit*>(MIOpInfo->getOperator()) \|\|
	dynamic_cast<DefInit*>(MIOpInfo->getOperator())
	->getDef()->getName() != "ops")
	throw "Bad value for MIOperandInfo in operand '" + Rec->getName() +
	"'\n";

	// If we have MIOpInfo, then we have #operands equal to number of entries
	// in MIOperandInfo.
	if (unsigned NumArgs = MIOpInfo->getNumArgs())
	NumOps = NumArgs;

	if (Rec->isSubClassOf("PredicateOperand"))
	isPredicable = true;
	else if (Rec->isSubClassOf("OptionalDefOperand"))
	hasOptionalDef = true;
	} else if (Rec->getName() == "variable_ops") {
	isVariadic = true;
	continue;
	} else if (!Rec->isSubClassOf("RegisterClass") &&
	Rec->getName() != "ptr_rc" && Rec->getName() != "unknown")
	throw "Unknown operand class '" + Rec->getName() +
	"' in '" + R->getName() + "' instruction!";

	// Check that the operand has a name and that it's unique.
	if (ArgName.empty())
	throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
	" has no name!";
	if (!OperandNames.insert(ArgName).second)
	throw "In instruction '" + R->getName() + "', operand #" + utostr(i) +
	" has the same name as a previous operand!";

	OperandList.push_back(OperandInfo(Rec, ArgName, PrintMethod, EncoderMethod,
	MIOperandNo, NumOps, MIOpInfo));
	MIOperandNo += NumOps;
	}


	// Make sure the constraints list for each operand is large enough to hold
	// constraint info, even if none is present.
	for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
	OperandList[i].Constraints.resize(OperandList[i].MINumOperands);
	}


	/// getOperandNamed - Return the index of the operand with the specified
	/// non-empty name. If the instruction does not have an operand with the
	/// specified name, throw an exception.
	///
	unsigned CGIOperandList::getOperandNamed(StringRef Name) const {
	unsigned OpIdx;
	if (hasOperandNamed(Name, OpIdx)) return OpIdx;
	throw "'" + TheDef->getName() + "' does not have an operand named '$" +
	Name.str() + "'!";
	}

	/// hasOperandNamed - Query whether the instruction has an operand of the
	/// given name. If so, return true and set OpIdx to the index of the
	/// operand. Otherwise, return false.
	bool CGIOperandList::hasOperandNamed(StringRef Name, unsigned &OpIdx) const {
	assert(!Name.empty() && "Cannot search for operand with no name!");
	for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
	if (OperandList[i].Name == Name) {
	OpIdx = i;
	return true;
	}
	return false;
	}

	std::pair<unsigned,unsigned>
	CGIOperandList::ParseOperandName(const std::string &Op, bool AllowWholeOp) {
	if (Op.empty() \|\| Op[0] != '$')
	throw TheDef->getName() + ": Illegal operand name: '" + Op + "'";

	std::string OpName = Op.substr(1);
	std::string SubOpName;

	// Check to see if this is $foo.bar.
	std::string::size_type DotIdx = OpName.find_first_of(".");
	if (DotIdx != std::string::npos) {
	SubOpName = OpName.substr(DotIdx+1);
	if (SubOpName.empty())
	throw TheDef->getName() + ": illegal empty suboperand name in '" +Op +"'";
	OpName = OpName.substr(0, DotIdx);
	}

	unsigned OpIdx = getOperandNamed(OpName);

	if (SubOpName.empty()) { // If no suboperand name was specified:
	// If one was needed, throw.
	if (OperandList[OpIdx].MINumOperands > 1 && !AllowWholeOp &&
	SubOpName.empty())
	throw TheDef->getName() + ": Illegal to refer to"
	" whole operand part of complex operand '" + Op + "'";

	// Otherwise, return the operand.
	return std::make_pair(OpIdx, 0U);
	}

	// Find the suboperand number involved.
	DagInit *MIOpInfo = OperandList[OpIdx].MIOperandInfo;
	if (MIOpInfo == 0)
	throw TheDef->getName() + ": unknown suboperand name in '" + Op + "'";

	// Find the operand with the right name.
	for (unsigned i = 0, e = MIOpInfo->getNumArgs(); i != e; ++i)
	if (MIOpInfo->getArgName(i) == SubOpName)
	return std::make_pair(OpIdx, i);

	// Otherwise, didn't find it!
	throw TheDef->getName() + ": unknown suboperand name in '" + Op + "'";
	}

	static void ParseConstraint(const std::string &CStr, CGIOperandList &Ops) {
	// EARLY_CLOBBER: @early $reg
	std::string::size_type wpos = CStr.find_first_of(" \t");
	std::string::size_type start = CStr.find_first_not_of(" \t");
	std::string Tok = CStr.substr(start, wpos - start);
	if (Tok == "@earlyclobber") {
	std::string Name = CStr.substr(wpos+1);
	wpos = Name.find_first_not_of(" \t");
	if (wpos == std::string::npos)
	throw "Illegal format for @earlyclobber constraint: '" + CStr + "'";
	Name = Name.substr(wpos);
	std::pair<unsigned,unsigned> Op = Ops.ParseOperandName(Name, false);

	// Build the string for the operand
	if (!Ops[Op.first].Constraints[Op.second].isNone())
	throw "Operand '" + Name + "' cannot have multiple constraints!";
	Ops[Op.first].Constraints[Op.second] =
	CGIOperandList::ConstraintInfo::getEarlyClobber();
	return;
	}

	// Only other constraint is "TIED_TO" for now.
	std::string::size_type pos = CStr.find_first_of('=');
	assert(pos != std::string::npos && "Unrecognized constraint");
	start = CStr.find_first_not_of(" \t");
	std::string Name = CStr.substr(start, pos - start);

	// TIED_TO: $src1 = $dst
	wpos = Name.find_first_of(" \t");
	if (wpos == std::string::npos)
	throw "Illegal format for tied-to constraint: '" + CStr + "'";
	std::string DestOpName = Name.substr(0, wpos);
	std::pair<unsigned,unsigned> DestOp = Ops.ParseOperandName(DestOpName, false);

	Name = CStr.substr(pos+1);
	wpos = Name.find_first_not_of(" \t");
	if (wpos == std::string::npos)
	throw "Illegal format for tied-to constraint: '" + CStr + "'";

	std::pair<unsigned,unsigned> SrcOp =
	Ops.ParseOperandName(Name.substr(wpos), false);
	if (SrcOp > DestOp)
	throw "Illegal tied-to operand constraint '" + CStr + "'";


	unsigned FlatOpNo = Ops.getFlattenedOperandNumber(SrcOp);

	if (!Ops[DestOp.first].Constraints[DestOp.second].isNone())
	throw "Operand '" + DestOpName + "' cannot have multiple constraints!";
	Ops[DestOp.first].Constraints[DestOp.second] =
	CGIOperandList::ConstraintInfo::getTied(FlatOpNo);
	}

	static void ParseConstraints(const std::string &CStr, CGIOperandList &Ops) {
	if (CStr.empty()) return;

	const std::string delims(",");
	std::string::size_type bidx, eidx;

	bidx = CStr.find_first_not_of(delims);
	while (bidx != std::string::npos) {
	eidx = CStr.find_first_of(delims, bidx);
	if (eidx == std::string::npos)
	eidx = CStr.length();

	ParseConstraint(CStr.substr(bidx, eidx - bidx), Ops);
	bidx = CStr.find_first_not_of(delims, eidx);
	}
	}

	void CGIOperandList::ProcessDisableEncoding(std::string DisableEncoding) {
	while (1) {
	std::string OpName;
	tie(OpName, DisableEncoding) = getToken(DisableEncoding, " ,\t");
	if (OpName.empty()) break;

	// Figure out which operand this is.
	std::pair<unsigned,unsigned> Op = ParseOperandName(OpName, false);

	// Mark the operand as not-to-be encoded.
	if (Op.second >= OperandList[Op.first].DoNotEncode.size())
	OperandList[Op.first].DoNotEncode.resize(Op.second+1);
	OperandList[Op.first].DoNotEncode[Op.second] = true;
	}

	}

	//===----------------------------------------------------------------------===//
	// CodeGenInstruction Implementation
	//===----------------------------------------------------------------------===//

	CodeGenInstruction::CodeGenInstruction(Record *R) : TheDef(R), Operands(R) {
	Namespace = R->getValueAsString("Namespace");
	AsmString = R->getValueAsString("AsmString");

	isReturn = R->getValueAsBit("isReturn");
	isBranch = R->getValueAsBit("isBranch");
	isIndirectBranch = R->getValueAsBit("isIndirectBranch");
	isCompare = R->getValueAsBit("isCompare");
	isMoveImm = R->getValueAsBit("isMoveImm");
	isBarrier = R->getValueAsBit("isBarrier");
	isCall = R->getValueAsBit("isCall");
	canFoldAsLoad = R->getValueAsBit("canFoldAsLoad");
	mayLoad = R->getValueAsBit("mayLoad");
	mayStore = R->getValueAsBit("mayStore");
	isPredicable = Operands.isPredicable \|\| R->getValueAsBit("isPredicable");
	isConvertibleToThreeAddress = R->getValueAsBit("isConvertibleToThreeAddress");
	isCommutable = R->getValueAsBit("isCommutable");
	isTerminator = R->getValueAsBit("isTerminator");
	isReMaterializable = R->getValueAsBit("isReMaterializable");
	hasDelaySlot = R->getValueAsBit("hasDelaySlot");
	usesCustomInserter = R->getValueAsBit("usesCustomInserter");
	hasCtrlDep = R->getValueAsBit("hasCtrlDep");
	isNotDuplicable = R->getValueAsBit("isNotDuplicable");
	hasSideEffects = R->getValueAsBit("hasSideEffects");
	neverHasSideEffects = R->getValueAsBit("neverHasSideEffects");
	isAsCheapAsAMove = R->getValueAsBit("isAsCheapAsAMove");
	hasExtraSrcRegAllocReq = R->getValueAsBit("hasExtraSrcRegAllocReq");
	hasExtraDefRegAllocReq = R->getValueAsBit("hasExtraDefRegAllocReq");
	ImplicitDefs = R->getValueAsListOfDefs("Defs");
	ImplicitUses = R->getValueAsListOfDefs("Uses");

	if (neverHasSideEffects + hasSideEffects > 1)
	throw R->getName() + ": multiple conflicting side-effect flags set!";

	// Parse Constraints.
	ParseConstraints(R->getValueAsString("Constraints"), Operands);

	// Parse the DisableEncoding field.
	Operands.ProcessDisableEncoding(R->getValueAsString("DisableEncoding"));
	}

	/// HasOneImplicitDefWithKnownVT - If the instruction has at least one
	/// implicit def and it has a known VT, return the VT, otherwise return
	/// MVT::Other.
	MVT::SimpleValueType CodeGenInstruction::
	HasOneImplicitDefWithKnownVT(const CodeGenTarget &TargetInfo) const {
	if (ImplicitDefs.empty()) return MVT::Other;

	// Check to see if the first implicit def has a resolvable type.
	Record *FirstImplicitDef = ImplicitDefs[0];
	assert(FirstImplicitDef->isSubClassOf("Register"));
	const std::vector<MVT::SimpleValueType> &RegVTs =
	TargetInfo.getRegisterVTs(FirstImplicitDef);
	if (RegVTs.size() == 1)
	return RegVTs[0];
	return MVT::Other;
	}


	/// FlattenAsmStringVariants - Flatten the specified AsmString to only
	/// include text from the specified variant, returning the new string.
	std::string CodeGenInstruction::
	FlattenAsmStringVariants(StringRef Cur, unsigned Variant) {
	std::string Res = "";

	for (;;) {
	// Find the start of the next variant string.
	size_t VariantsStart = 0;
	for (size_t e = Cur.size(); VariantsStart != e; ++VariantsStart)
	if (Cur[VariantsStart] == '{' &&
	(VariantsStart == 0 \|\| (Cur[VariantsStart-1] != '$' &&
	Cur[VariantsStart-1] != '\\')))
	break;

	// Add the prefix to the result.
	Res += Cur.slice(0, VariantsStart);
	if (VariantsStart == Cur.size())
	break;

	++VariantsStart; // Skip the '{'.

	// Scan to the end of the variants string.
	size_t VariantsEnd = VariantsStart;
	unsigned NestedBraces = 1;
	for (size_t e = Cur.size(); VariantsEnd != e; ++VariantsEnd) {
	if (Cur[VariantsEnd] == '}' && Cur[VariantsEnd-1] != '\\') {
	if (--NestedBraces == 0)
	break;
	} else if (Cur[VariantsEnd] == '{')
	++NestedBraces;
	}

	// Select the Nth variant (or empty).
	StringRef Selection = Cur.slice(VariantsStart, VariantsEnd);
	for (unsigned i = 0; i != Variant; ++i)
	Selection = Selection.split('\|').second;
	Res += Selection.split('\|').first;

	assert(VariantsEnd != Cur.size() &&
	"Unterminated variants in assembly string!");
	Cur = Cur.substr(VariantsEnd + 1);
	}

	return Res;
	}


	//===----------------------------------------------------------------------===//
	/// CodeGenInstAlias Implementation
	//===----------------------------------------------------------------------===//

	CodeGenInstAlias::CodeGenInstAlias(Record *R, CodeGenTarget &T) : TheDef(R) {
	AsmString = R->getValueAsString("AsmString");
	Result = R->getValueAsDag("ResultInst");

	// Verify that the root of the result is an instruction.
	DefInit DI = dynamic_cast<DefInit>(Result->getOperator());
	if (DI == 0 \|\| !DI->getDef()->isSubClassOf("Instruction"))
	throw TGError(R->getLoc(), "result of inst alias should be an instruction");

	ResultInst = &T.getInstruction(DI->getDef());

	// NameClass - If argument names are repeated, we need to verify they have
	// the same class.
	StringMap<Record*> NameClass;

	// Decode and validate the arguments of the result.
	unsigned AliasOpNo = 0;
	for (unsigned i = 0, e = ResultInst->Operands.size(); i != e; ++i) {
	// Tied registers don't have an entry in the result dag.
	if (ResultInst->Operands[i].getTiedRegister() != -1)
	continue;

	if (AliasOpNo >= Result->getNumArgs())
	throw TGError(R->getLoc(), "result has " + utostr(Result->getNumArgs()) +
	" arguments, but " + ResultInst->TheDef->getName() +
	" instruction expects " +
	utostr(ResultInst->Operands.size()) + " operands!");


	Init *Arg = Result->getArg(AliasOpNo);
	Record *ResultOpRec = ResultInst->Operands[i].Rec;

	// Handle explicit registers.
	if (DefInit ADI = dynamic_cast<DefInit>(Arg)) {
	if (ADI->getDef()->isSubClassOf("Register")) {
	if (!Result->getArgName(AliasOpNo).empty())
	throw TGError(R->getLoc(), "result fixed register argument must "
	"not have a name!");

	if (!ResultOpRec->isSubClassOf("RegisterClass"))
	throw TGError(R->getLoc(), "result fixed register argument is not "
	"passed to a RegisterClass operand!");

	if (!T.getRegisterClass(ResultOpRec).containsRegister(ADI->getDef()))
	throw TGError(R->getLoc(), "fixed register " +ADI->getDef()->getName()
	+ " is not a member of the " + ResultOpRec->getName() +
	" register class!");

	// Now that it is validated, add it.
	ResultOperands.push_back(ResultOperand(ADI->getDef()));
	++AliasOpNo;
	continue;
	}
	if (ADI->getDef()->getName() == "zero_reg") {
	if (!Result->getArgName(AliasOpNo).empty())
	throw TGError(R->getLoc(), "result fixed register argument must "
	"not have a name!");

	// Check if this is an optional def.
	if (!ResultOpRec->isSubClassOf("OptionalDefOperand"))
	throw TGError(R->getLoc(), "reg0 used for result that is not an "
	"OptionalDefOperand!");

	// Now that it is validated, add it.
	ResultOperands.push_back(ResultOperand(static_cast<Record*>(0)));
	++AliasOpNo;
	continue;
	}
	}

	// If the operand is a record, it must have a name, and the record type must
	// match up with the instruction's argument type.
	if (DefInit ADI = dynamic_cast<DefInit>(Arg)) {
	if (Result->getArgName(AliasOpNo).empty())
	throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
	" must have a name!");

	if (ADI->getDef() != ResultOpRec)
	throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
	" declared with class " + ADI->getDef()->getName() +
	", instruction operand is class " +
	ResultOpRec->getName());

	// Verify we don't have something like: (someinst GR16:$foo, GR32:$foo)
	// $foo can exist multiple times in the result list, but it must have the
	// same type.
	Record *&Entry = NameClass[Result->getArgName(AliasOpNo)];
	if (Entry && Entry != ADI->getDef())
	throw TGError(R->getLoc(), "result value $" +
	Result->getArgName(AliasOpNo) +
	" is both " + Entry->getName() + " and " +
	ADI->getDef()->getName() + "!");

	// Now that it is validated, add it.
	ResultOperands.push_back(ResultOperand(Result->getArgName(AliasOpNo),
	ADI->getDef()));
	++AliasOpNo;
	continue;
	}

	if (IntInit II = dynamic_cast<IntInit>(Arg)) {
	// Integer arguments can't have names.
	if (!Result->getArgName(AliasOpNo).empty())
	throw TGError(R->getLoc(), "result argument #" + utostr(AliasOpNo) +
	" must not have a name!");
	if (ResultInst->Operands[i].MINumOperands != 1 \|\|
	!ResultOpRec->isSubClassOf("Operand"))
	throw TGError(R->getLoc(), "invalid argument class " +
	ResultOpRec->getName() +
	" for integer result operand!");
	ResultOperands.push_back(ResultOperand(II->getValue()));
	++AliasOpNo;
	continue;
	}

	throw TGError(R->getLoc(), "result of inst alias has unknown operand type");
	}

	if (AliasOpNo != Result->getNumArgs())
	throw TGError(R->getLoc(), "result has " + utostr(Result->getNumArgs()) +
	" arguments, but " + ResultInst->TheDef->getName() +
	" instruction expects " + utostr(ResultInst->Operands.size())+
	" operands!");
	}

	/// getResultInstOperandIndexForResultOperandIndex - Given an index into the
	/// ResultOperands array, translate it to a valid index in ResultInst's
	/// operand list.
	unsigned CodeGenInstAlias::
	getResultInstOperandIndexForResultOperandIndex(unsigned OpNo) const {
	unsigned OpIdx = 0;

	for (unsigned i = 0;; ++i) {
	assert(i != ResultInst->Operands.size() && "Didn't find entry");
	if (ResultInst->Operands[i].getTiedRegister() != -1)
	continue;

	if (OpIdx == OpNo) return i;

	++OpIdx;
	}
	}