Subzero: Refactor tracking of Defs and block-local Variables.

src/IceTargetLoweringX8632.cpp

 //===- subzero/src/IceTargetLoweringX8632.cpp - x86-32 lowering -----------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the TargetLoweringX8632 class, which
@@ skipping 304 matching lines @@
   T_placePhiStores.printElapsedUs(Context, "placePhiStores()");
   Timer T_deletePhis;
   Func->deletePhis();
   if (Func->hasError())
     return;
   T_deletePhis.printElapsedUs(Context, "deletePhis()");
   Func->dump("After Phi lowering");
 
   // Address mode optimization.
   Timer T_doAddressOpt;
+  Func->getVMetadata()->init();
   Func->doAddressOpt();
   T_doAddressOpt.printElapsedUs(Context, "doAddressOpt()");
 
   // Argument lowering
   Timer T_argLowering;
   Func->doArgLowering();
   T_argLowering.printElapsedUs(Context, "lowerArguments()");
 
   // Target lowering.  This requires liveness analysis for some parts
   // of the lowering decisions, such as compare/branch fusing.  If
@@ skipping 128 matching lines @@
           frameptr, isI8, isInt, isFP)                                         \
   name,
   REGX8632_TABLE
 #undef X
 };
 
 Variable *TargetX8632::getPhysicalRegister(SizeT RegNum) {
   assert(RegNum < PhysicalRegisters.size());
   Variable *Reg = PhysicalRegisters[RegNum];
   if (Reg == NULL) {
-    CfgNode *Node = NULL; // NULL means multi-block lifetime
-    Reg = Func->makeVariable(IceType_i32, Node);
+    Reg = Func->makeVariable(IceType_i32);
     Reg->setRegNum(RegNum);
     PhysicalRegisters[RegNum] = Reg;
+    // Specially mark esp as an "argument" so that it is considered
+    // live upon function entry.
+    if (RegNum == RegX8632::Reg_esp)
+      Func->addImplicitArg(Reg);
   }
   return Reg;
 }
 
 IceString TargetX8632::getRegName(SizeT RegNum, Type Ty) const {
   assert(RegNum < RegX8632::Reg_NUM);
   static IceString RegNames8[] = {
 #define X(val, encode, name, name16, name8, scratch, preserved, stackptr,      \
           frameptr, isI8, isInt, isFP)                                         \
   name8,
@@ skipping 11 matching lines @@
   case IceType_i1:
   case IceType_i8:
     return RegNames8[RegNum];
   case IceType_i16:
     return RegNames16[RegNum];
   default:
     return RegNames[RegNum];
   }
 }
 
-void TargetX8632::emitVariable(const Variable *Var, const Cfg *Func) const {
+void TargetX8632::emitVariable(const Variable *Var) const {
   Ostream &Str = Ctx->getStrEmit();
-  assert(Var->getLocalUseNode() == NULL ||
-         Var->getLocalUseNode() == Func->getCurrentNode());
   if (Var->hasReg()) {
     Str << getRegName(Var->getRegNum(), Var->getType());
     return;
   }
   Str << InstX8632::getWidthString(Var->getType());
   Str << " [" << getRegName(getFrameOrStackReg(), IceType_i32);
   int32_t Offset = Var->getStackOffset();
   if (!hasFramePointer())
     Offset += getStackAdjustment();
   if (Offset) {
@@ skipping 19 matching lines @@
     Variable *Arg = Args[I];
     Type Ty = Arg->getType();
     if (!isVectorType(Ty))
       continue;
     // Replace Arg in the argument list with the home register.  Then
     // generate an instruction in the prolog to copy the home register
     // to the assigned location of Arg.
     int32_t RegNum = RegX8632::Reg_xmm0 + NumXmmArgs;
     ++NumXmmArgs;
     IceString Name = "home_reg:" + Arg->getName();
-    const CfgNode *DefNode = NULL;
-    Variable *RegisterArg = Func->makeVariable(Ty, DefNode, Name);
+    Variable *RegisterArg = Func->makeVariable(Ty, Name);
     RegisterArg->setRegNum(RegNum);
-    RegisterArg->setIsArg(Func);
-    Arg->setIsArg(Func, false);
+    RegisterArg->setIsArg();
+    Arg->setIsArg(false);
 
     Args[I] = RegisterArg;
     Context.insert(InstAssign::create(Func, Arg, RegisterArg));
   }
 }
 
 void TargetX8632::sortByAlignment(VarList &Dest, const VarList &Source) const {
   // Sort the variables into buckets according to the log of their width
   // in bytes.
   const SizeT NumBuckets =
@@ skipping 102 matching lines @@
   // block 1 and C is local to block 2, then C may share a slot with A or B.
   //
   // We cannot coalesce stack slots if this function calls a "returns twice"
   // function. In that case, basic blocks may be revisited, and variables
   // local to those basic blocks are actually live until after the
   // called function returns a second time.
   const bool SimpleCoalescing = !callsReturnsTwice();
   size_t InArgsSizeBytes = 0;
   size_t PreservedRegsSizeBytes = 0;
   SpillAreaSizeBytes = 0;
+  const VariablesMetadata *VMetadata = Func->getVMetadata();
   Context.init(Node);
   Context.setInsertPoint(Context.getCur());
 
   // Determine stack frame offsets for each Variable without a
   // register assignment.  This can be done as one variable per stack
   // slot.  Or, do coalescing by running the register allocator again
   // with an infinite set of registers (as a side effect, this gives
   // variables a second chance at physical register assignment).
   //
   // A middle ground approach is to leverage sparsity and allocate one
@@ skipping 48 matching lines @@
 
   SortedSpilledVariables.reserve(SpilledVariables.size());
   sortByAlignment(SortedSpilledVariables, SpilledVariables);
   for (VarList::const_iterator I = SortedSpilledVariables.begin(),
                                E = SortedSpilledVariables.end();
        I != E; ++I) {
     Variable *Var = *I;
     size_t Increment = typeWidthInBytesOnStack(Var->getType());
     if (!SpillAreaAlignmentBytes)
       SpillAreaAlignmentBytes = Increment;
-    if (SimpleCoalescing) {
-      if (Var->isMultiblockLife()) {
+    if (SimpleCoalescing && VMetadata->isTracked(Var)) {
+      if (VMetadata->isMultiBlock(Var)) {
         GlobalsSize += Increment;
       } else {
-        SizeT NodeIndex = Var->getLocalUseNode()->getIndex();
+        SizeT NodeIndex = VMetadata->getLocalUseNode(Var)->getIndex();
         LocalsSize[NodeIndex] += Increment;
         if (LocalsSize[NodeIndex] > SpillAreaSizeBytes)
           SpillAreaSizeBytes = LocalsSize[NodeIndex];
         if (!LocalsSlotsAlignmentBytes)
           LocalsSlotsAlignmentBytes = Increment;
       }
     } else {
       SpillAreaSizeBytes += Increment;
     }
   }
@@ skipping 84 matching lines @@
 
   // Fill in stack offsets for locals.
   size_t GlobalsSpaceUsed = SpillAreaPaddingBytes;
   LocalsSize.assign(LocalsSize.size(), 0);
   size_t NextStackOffset = GlobalsSpaceUsed;
   for (VarList::const_iterator I = SortedSpilledVariables.begin(),
                                E = SortedSpilledVariables.end();
        I != E; ++I) {
     Variable *Var = *I;
     size_t Increment = typeWidthInBytesOnStack(Var->getType());
-    if (SimpleCoalescing) {
-      if (Var->isMultiblockLife()) {
+    if (SimpleCoalescing && VMetadata->isTracked(Var)) {
+      if (VMetadata->isMultiBlock(Var)) {
         GlobalsSpaceUsed += Increment;
         NextStackOffset = GlobalsSpaceUsed;
       } else {
-        SizeT NodeIndex = Var->getLocalUseNode()->getIndex();
+        SizeT NodeIndex = VMetadata->getLocalUseNode(Var)->getIndex();
         LocalsSize[NodeIndex] += Increment;
         NextStackOffset = SpillAreaPaddingBytes +
                           GlobalsAndSubsequentPaddingSize +
                           LocalsSize[NodeIndex];
       }
     } else {
       NextStackOffset += Increment;
     }
     if (IsEbpBasedFrame)
       Var->setStackOffset(-NextStackOffset);
@@ skipping 157 matching lines @@
   case IceType_f64:
     break;
   }
   Variable *Lo = Var->getLo();
   Variable *Hi = Var->getHi();
   if (Lo) {
     assert(Hi);
     return;
   }
   assert(Hi == NULL);
-  Lo = Func->makeVariable(IceType_i32, Context.getNode(),
-                          Var->getName() + "__lo");
-  Hi = Func->makeVariable(IceType_i32, Context.getNode(),
-                          Var->getName() + "__hi");
+  Lo = Func->makeVariable(IceType_i32, Var->getName() + "__lo");
+  Hi = Func->makeVariable(IceType_i32, Var->getName() + "__hi");
   Var->setLoHi(Lo, Hi);
   if (Var->getIsArg()) {
-    Lo->setIsArg(Func);
-    Hi->setIsArg(Func);
+    Lo->setIsArg();
+    Hi->setIsArg();
   }
 }
 
 Operand *TargetX8632::loOperand(Operand *Operand) {
   assert(Operand->getType() == IceType_i64);
   if (Operand->getType() != IceType_i64)
     return Operand;
   if (Variable *Var = llvm::dyn_cast<Variable>(Operand)) {
     split64(Var);
     return Var->getLo();
@@ skipping 1213 matching lines @@
       (void)DestType;
       assert((DestType == IceType_i32 && SrcType == IceType_f32) ||
              (DestType == IceType_f32 && SrcType == IceType_i32));
       // a.i32 = bitcast b.f32 ==>
       //   t.f32 = b.f32
       //   s.f32 = spill t.f32
       //   a.i32 = s.f32
       Variable *T = NULL;
       // TODO: Should be able to force a spill setup by calling legalize() with
       // Legal_Mem and not Legal_Reg or Legal_Imm.
-      SpillVariable *SpillVar =
-          Func->makeVariable<SpillVariable>(SrcType, Context.getNode());
+      SpillVariable *SpillVar = Func->makeVariable<SpillVariable>(SrcType);
       SpillVar->setLinkedTo(Dest);
       Variable *Spill = SpillVar;
       Spill->setWeight(RegWeight::Zero);
       _mov(T, Src0RM);
       _mov(Spill, T);
       _mov(Dest, Spill);
     } break;
     case IceType_i64: {
       Operand *Src0RM = legalize(Src0, Legal_Reg | Legal_Mem);
       assert(Src0RM->getType() == IceType_f64);
       // a.i64 = bitcast b.f64 ==>
       //   s.f64 = spill b.f64
       //   t_lo.i32 = lo(s.f64)
       //   a_lo.i32 = t_lo.i32
       //   t_hi.i32 = hi(s.f64)
       //   a_hi.i32 = t_hi.i32
-      SpillVariable *SpillVar =
-          Func->makeVariable<SpillVariable>(IceType_f64, Context.getNode());
+      SpillVariable *SpillVar = Func->makeVariable<SpillVariable>(IceType_f64);
       SpillVar->setLinkedTo(llvm::dyn_cast<Variable>(Src0RM));
       Variable *Spill = SpillVar;
       Spill->setWeight(RegWeight::Zero);
       _movq(Spill, Src0RM);
 
       Variable *DestLo = llvm::cast<Variable>(loOperand(Dest));
       Variable *DestHi = llvm::cast<Variable>(hiOperand(Dest));
       Variable *T_Lo = makeReg(IceType_i32);
       Variable *T_Hi = makeReg(IceType_i32);
       VariableSplit *SpillLo =
           VariableSplit::create(Func, Spill, VariableSplit::Low);
       VariableSplit *SpillHi =
           VariableSplit::create(Func, Spill, VariableSplit::High);
 
       _mov(T_Lo, SpillLo);
       _mov(DestLo, T_Lo);
       _mov(T_Hi, SpillHi);
       _mov(DestHi, T_Hi);
     } break;
     case IceType_f64: {
       Src0 = legalize(Src0);
       assert(Src0->getType() == IceType_i64);
       // a.f64 = bitcast b.i64 ==>
       //   t_lo.i32 = b_lo.i32
       //   FakeDef(s.f64)
       //   lo(s.f64) = t_lo.i32
       //   t_hi.i32 = b_hi.i32
       //   hi(s.f64) = t_hi.i32
       //   a.f64 = s.f64
-      SpillVariable *SpillVar =
-          Func->makeVariable<SpillVariable>(IceType_f64, Context.getNode());
+      SpillVariable *SpillVar = Func->makeVariable<SpillVariable>(IceType_f64);
       SpillVar->setLinkedTo(Dest);
       Variable *Spill = SpillVar;
       Spill->setWeight(RegWeight::Zero);
 
       Variable *T_Lo = NULL, *T_Hi = NULL;
       VariableSplit *SpillLo =
           VariableSplit::create(Func, Spill, VariableSplit::Low);
       VariableSplit *SpillHi =
           VariableSplit::create(Func, Spill, VariableSplit::High);
       _mov(T_Lo, loOperand(Src0));
       // Technically, the Spill is defined after the _store happens, but
       // SpillLo is considered a "use" of Spill so define Spill before it
       // is used.
       Context.insert(InstFakeDef::create(Func, Spill));
       _store(T_Lo, SpillLo);
       _mov(T_Hi, hiOperand(Src0));
       _store(T_Hi, SpillHi);
       _movq(Dest, Spill);
     } break;
     case IceType_v8i1: {
       assert(Src0->getType() == IceType_i8);
       InstCall *Call = makeHelperCall("Sz_bitcast_i8_to_v8i1", Dest, 1);
-      Variable *Src0AsI32 = Func->makeVariable(stackSlotType(),
-                                               Context.getNode());
+      Variable *Src0AsI32 = Func->makeVariable(stackSlotType());
       // Arguments to functions are required to be at least 32 bits wide.
       lowerCast(InstCast::create(Func, InstCast::Zext, Src0AsI32, Src0));
       Call->addArg(Src0AsI32);
       lowerCall(Call);
     } break;
     case IceType_v16i1: {
       assert(Src0->getType() == IceType_i16);
       InstCall *Call = makeHelperCall("Sz_bitcast_i16_to_v16i1", Dest, 1);
-      Variable *Src0AsI32 = Func->makeVariable(stackSlotType(),
-                                               Context.getNode());
+      Variable *Src0AsI32 = Func->makeVariable(stackSlotType());
       // Arguments to functions are required to be at least 32 bits wide.
       lowerCast(InstCast::create(Func, InstCast::Zext, Src0AsI32, Src0));
       Call->addArg(Src0AsI32);
       lowerCall(Call);
     } break;
     case IceType_v8i16:
     case IceType_v16i8:
     case IceType_v4i32:
     case IceType_v4f32: {
       _movp(Dest, legalizeToVar(Src0));
@@ skipping 48 matching lines @@
       // keep the live range analysis consistent.
       Context.insert(InstFakeDef::create(Func, ExtractedElementR));
       _movss(ExtractedElementR, T);
     }
   } else {
     assert(Ty == IceType_v16i8 || Ty == IceType_v16i1);
     // Spill the value to a stack slot and do the extraction in memory.
     //
     // TODO(wala): use legalize(SourceVectNotLegalized, Legal_Mem) when
     // support for legalizing to mem is implemented.
-    Variable *Slot = Func->makeVariable(Ty, Context.getNode());
+    Variable *Slot = Func->makeVariable(Ty);
     Slot->setWeight(RegWeight::Zero);
     _movp(Slot, legalizeToVar(SourceVectNotLegalized));
 
     // Compute the location of the element in memory.
     unsigned Offset = Index * typeWidthInBytes(InVectorElementTy);
     OperandX8632Mem *Loc =
         getMemoryOperandForStackSlot(InVectorElementTy, Slot, Offset);
     _mov(ExtractedElementR, Loc);
   }
 
@@ skipping 134 matching lines @@
       case IceType_v4i1:
         NewTy = IceType_v4i32;
         break;
       case IceType_v8i1:
         NewTy = IceType_v8i16;
         break;
       case IceType_v16i1:
         NewTy = IceType_v16i8;
         break;
       }
-      Variable *NewSrc0 = Func->makeVariable(NewTy, Context.getNode());
-      Variable *NewSrc1 = Func->makeVariable(NewTy, Context.getNode());
+      Variable *NewSrc0 = Func->makeVariable(NewTy);
+      Variable *NewSrc1 = Func->makeVariable(NewTy);
       lowerCast(InstCast::create(Func, InstCast::Sext, NewSrc0, Src0));
       lowerCast(InstCast::create(Func, InstCast::Sext, NewSrc1, Src1));
       Src0 = NewSrc0;
       Src1 = NewSrc1;
       Ty = NewTy;
     }
 
     InstIcmp::ICond Condition = Inst->getCondition();
 
     Operand *Src0RM = legalize(Src0, Legal_Reg | Legal_Mem);
@@ skipping 154 matching lines @@
   unsigned Index = ElementIndex->getValue();
   assert(Index < typeNumElements(SourceVectNotLegalized->getType()));
 
   Type Ty = SourceVectNotLegalized->getType();
   Type ElementTy = typeElementType(Ty);
   Type InVectorElementTy = getInVectorElementType(Ty);
 
   if (ElementTy == IceType_i1) {
     // Expand the element to the appropriate size for it to be inserted
     // in the vector.
-    Variable *Expanded =
-        Func->makeVariable(InVectorElementTy, Context.getNode());
+    Variable *Expanded = Func->makeVariable(InVectorElementTy);
     InstCast *Cast = InstCast::create(Func, InstCast::Zext, Expanded,
                                       ElementToInsertNotLegalized);
     lowerCast(Cast);
     ElementToInsertNotLegalized = Expanded;
   }
 
   if (Ty == IceType_v8i16 || Ty == IceType_v8i1 || InstructionSet >= SSE4_1) {
     // Use insertps, pinsrb, pinsrw, or pinsrd.
     Operand *ElementRM =
         legalize(ElementToInsertNotLegalized, Legal_Reg | Legal_Mem);
@@ skipping 71 matching lines @@
       _shufps(T, ElementR, Mask2Constant);
       _movp(Inst->getDest(), T);
     }
   } else {
     assert(Ty == IceType_v16i8 || Ty == IceType_v16i1);
     // Spill the value to a stack slot and perform the insertion in
     // memory.
     //
     // TODO(wala): use legalize(SourceVectNotLegalized, Legal_Mem) when
     // support for legalizing to mem is implemented.
-    Variable *Slot = Func->makeVariable(Ty, Context.getNode());
+    Variable *Slot = Func->makeVariable(Ty);
     Slot->setWeight(RegWeight::Zero);
     _movp(Slot, legalizeToVar(SourceVectNotLegalized));
 
     // Compute the location of the position to insert in memory.
     unsigned Offset = Index * typeWidthInBytes(InVectorElementTy);
     OperandX8632Mem *Loc =
         getMemoryOperandForStackSlot(InVectorElementTy, Slot, Offset);
     _store(legalizeToVar(ElementToInsertNotLegalized), Loc);
 
     Variable *T = makeReg(Ty);
@@ skipping 249 matching lines @@
     Call->addArg(Instr->getArg(2));
     lowerCall(Call);
     return;
   }
   case Intrinsics::Memset: {
     // The value operand needs to be extended to a stack slot size
     // because the PNaCl ABI requires arguments to be at least 32 bits
     // wide.
     Operand *ValOp = Instr->getArg(1);
     assert(ValOp->getType() == IceType_i8);
-    Variable *ValExt = Func->makeVariable(stackSlotType(), Context.getNode());
+    Variable *ValExt = Func->makeVariable(stackSlotType());
     lowerCast(InstCast::create(Func, InstCast::Zext, ValExt, ValOp));
     InstCall *Call = makeHelperCall("memset", NULL, 3);
     Call->addArg(Instr->getArg(0));
     Call->addArg(ValExt);
     Call->addArg(Instr->getArg(2));
     lowerCall(Call);
     return;
   }
   case Intrinsics::NaClReadTP: {
     if (Ctx->getFlags().UseSandboxing) {
@@ skipping 435 matching lines @@
   else
     Str << "<null>";
   Str << ", Index=";
   if (Index)
     Index->dump(Func);
   else
     Str << "<null>";
   Str << ", Shift=" << Shift << ", Offset=" << Offset << "\n";
 }
 
-bool matchTransitiveAssign(Variable *&Var, const Inst *&Reason) {
+bool matchTransitiveAssign(const VariablesMetadata *VMetadata, Variable *&Var,
+                           const Inst *&Reason) {
   // Var originates from Var=SrcVar ==>
   //   set Var:=SrcVar
   if (Var == NULL)
     return false;
-  if (const Inst *VarAssign = Var->getDefinition()) {
+  if (const Inst *VarAssign = VMetadata->getDefinition(Var)) {
     if (llvm::isa<InstAssign>(VarAssign)) {
       Operand *SrcOp = VarAssign->getSrc(0);
       assert(SrcOp);
       if (Variable *SrcVar = llvm::dyn_cast<Variable>(SrcOp)) {
-        if (!SrcVar->getIsMultidef() &&
+        if (!VMetadata->isMultiDef(SrcVar) &&
             // TODO: ensure SrcVar stays single-BB
             true) {
           Var = SrcVar;
           Reason = VarAssign;
           return true;
         }
       }
     }
   }
   return false;
 }
 
-bool matchCombinedBaseIndex(Variable *&Base, Variable *&Index, uint16_t &Shift,
+bool matchCombinedBaseIndex(const VariablesMetadata *VMetadata, Variable *&Base,
+                            Variable *&Index, uint16_t &Shift,
                             const Inst *&Reason) {
   // Index==NULL && Base is Base=Var1+Var2 ==>
   //   set Base=Var1, Index=Var2, Shift=0
   if (Base == NULL)
     return false;
   if (Index != NULL)
     return false;
-  const Inst *BaseInst = Base->getDefinition();
+  const Inst *BaseInst = VMetadata->getDefinition(Base);
   if (BaseInst == NULL)
     return false;
   if (BaseInst->getSrcSize() < 2)
     return false;
   if (Variable *Var1 = llvm::dyn_cast<Variable>(BaseInst->getSrc(0))) {
-    if (Var1->getIsMultidef())
+    if (VMetadata->isMultiDef(Var1))
       return false;
     if (Variable *Var2 = llvm::dyn_cast<Variable>(BaseInst->getSrc(1))) {
-      if (Var2->getIsMultidef())
+      if (VMetadata->isMultiDef(Var2))
         return false;
       if (isAdd(BaseInst) &&
           // TODO: ensure Var1 and Var2 stay single-BB
           true) {
         Base = Var1;
         Index = Var2;
         Shift = 0; // should already have been 0
         Reason = BaseInst;
         return true;
       }
     }
   }
   return false;
 }
 
-bool matchShiftedIndex(Variable *&Index, uint16_t &Shift, const Inst *&Reason) {
+bool matchShiftedIndex(const VariablesMetadata *VMetadata, Variable *&Index,
+                       uint16_t &Shift, const Inst *&Reason) {
   // Index is Index=Var*Const && log2(Const)+Shift<=3 ==>
   //   Index=Var, Shift+=log2(Const)
   if (Index == NULL)
     return false;
-  const Inst *IndexInst = Index->getDefinition();
+  const Inst *IndexInst = VMetadata->getDefinition(Index);
   if (IndexInst == NULL)
     return false;
   if (IndexInst->getSrcSize() < 2)
     return false;
   if (const InstArithmetic *ArithInst =
           llvm::dyn_cast<InstArithmetic>(IndexInst)) {
     if (Variable *Var = llvm::dyn_cast<Variable>(ArithInst->getSrc(0))) {
       if (ConstantInteger32 *Const =
               llvm::dyn_cast<ConstantInteger32>(ArithInst->getSrc(1))) {
         if (ArithInst->getOp() == InstArithmetic::Mul &&
-            !Var->getIsMultidef() && Const->getType() == IceType_i32) {
+            !VMetadata->isMultiDef(Var) && Const->getType() == IceType_i32) {
           uint64_t Mult = Const->getValue();
           uint32_t LogMult;
           switch (Mult) {
           case 1:
             LogMult = 0;
             break;
           case 2:
             LogMult = 1;
             break;
           case 4:
@@ skipping 11 matching lines @@
             Reason = IndexInst;
             return true;
           }
         }
       }
     }
   }
   return false;
 }
 
-bool matchOffsetBase(Variable *&Base, int32_t &Offset, const Inst *&Reason) {
+bool matchOffsetBase(const VariablesMetadata *VMetadata, Variable *&Base,
+                     int32_t &Offset, const Inst *&Reason) {
   // Base is Base=Var+Const || Base is Base=Const+Var ==>
   //   set Base=Var, Offset+=Const
   // Base is Base=Var-Const ==>
   //   set Base=Var, Offset-=Const
   if (Base == NULL)
     return false;
-  const Inst *BaseInst = Base->getDefinition();
+  const Inst *BaseInst = VMetadata->getDefinition(Base);
   if (BaseInst == NULL)
     return false;
   if (const InstArithmetic *ArithInst =
           llvm::dyn_cast<const InstArithmetic>(BaseInst)) {
     if (ArithInst->getOp() != InstArithmetic::Add &&
         ArithInst->getOp() != InstArithmetic::Sub)
       return false;
     bool IsAdd = ArithInst->getOp() == InstArithmetic::Add;
     Variable *Var = NULL;
     ConstantInteger32 *Const = NULL;
     if (Variable *VariableOperand =
             llvm::dyn_cast<Variable>(ArithInst->getSrc(0))) {
       Var = VariableOperand;
       Const = llvm::dyn_cast<ConstantInteger32>(ArithInst->getSrc(1));
     } else if (IsAdd) {
       Const = llvm::dyn_cast<ConstantInteger32>(ArithInst->getSrc(0));
       Var = llvm::dyn_cast<Variable>(ArithInst->getSrc(1));
     }
-    if (Var == NULL || Const == NULL || Var->getIsMultidef())
+    if (Var == NULL || Const == NULL || VMetadata->isMultiDef(Var))
       return false;
     int32_t MoreOffset = IsAdd ? Const->getValue() : -Const->getValue();
     if (WouldOverflowAdd(Offset, MoreOffset))
       return false;
     Base = Var;
     Offset += MoreOffset;
     Reason = BaseInst;
     return true;
   }
   return false;
 }
 
 void computeAddressOpt(Cfg *Func, const Inst *Instr, Variable *&Base,
                        Variable *&Index, uint16_t &Shift, int32_t &Offset) {
   Func->resetCurrentNode();
   if (Func->getContext()->isVerbose(IceV_AddrOpt)) {
     Ostream &Str = Func->getContext()->getStrDump();
     Str << "\nStarting computeAddressOpt for instruction:\n  ";
     Instr->dumpDecorated(Func);
   }
   (void)Offset; // TODO: pattern-match for non-zero offsets.
   if (Base == NULL)
     return;
   // If the Base has more than one use or is live across multiple
   // blocks, then don't go further.  Alternatively (?), never consider
   // a transformation that would change a variable that is currently
   // *not* live across basic block boundaries into one that *is*.
-  if (Base->isMultiblockLife() /* || Base->getUseCount() > 1*/)
+  if (Func->getVMetadata()->isMultiBlock(Base) /* || Base->getUseCount() > 1*/)
     return;
 
+  const VariablesMetadata *VMetadata = Func->getVMetadata();
   bool Continue = true;
   while (Continue) {
     const Inst *Reason = NULL;
-    if (matchTransitiveAssign(Base, Reason) ||
-        matchTransitiveAssign(Index, Reason) ||
-        matchCombinedBaseIndex(Base, Index, Shift, Reason) ||
-        matchShiftedIndex(Index, Shift, Reason) ||
-        matchOffsetBase(Base, Offset, Reason)) {
+    if (matchTransitiveAssign(VMetadata, Base, Reason) ||
+        matchTransitiveAssign(VMetadata, Index, Reason) ||
+        matchCombinedBaseIndex(VMetadata, Base, Index, Shift, Reason) ||
+        matchShiftedIndex(VMetadata, Index, Shift, Reason) ||
+        matchOffsetBase(VMetadata, Base, Offset, Reason)) {
       dumpAddressOpt(Func, Base, Index, Shift, Offset, Reason);
     } else {
       Continue = false;
     }
 
     // Index is Index=Var<<Const && Const+Shift<=3 ==>
     //   Index=Var, Shift+=Const
 
     // Index is Index=Const*Var && log2(Const)+Shift<=3 ==>
     //   Index=Var, Shift+=log2(Const)
@@ skipping 171 matching lines @@
     }
     // Lower select without SSE4.1:
     // a=d?b:c ==>
     //   if elementtype(d) != i1:
     //      d=sext(d);
     //   a=(b&d)|(c&~d);
     Variable *T2 = makeReg(SrcTy);
     // Sign extend the condition operand if applicable.
     if (SrcTy == IceType_v4f32) {
       // The sext operation takes only integer arguments.
-      Variable *T3 = Func->makeVariable(IceType_v4i32, Context.getNode());
+      Variable *T3 = Func->makeVariable(IceType_v4i32);
       lowerCast(InstCast::create(Func, InstCast::Sext, T3, Condition));
       _movp(T, T3);
     } else if (typeElementType(SrcTy) != IceType_i1) {
       lowerCast(InstCast::create(Func, InstCast::Sext, T, Condition));
     } else {
       Operand *ConditionRM = legalize(Condition, Legal_Reg | Legal_Mem);
       _movp(T, ConditionRM);
     }
     _movp(T2, T);
     _pand(T, SrcTRM);
@@ skipping 110 matching lines @@
   assert(isVectorType(Dest->getType()));
   Type Ty = Dest->getType();
   Type ElementTy = typeElementType(Ty);
   SizeT NumElements = typeNumElements(Ty);
 
   Operand *T = Ctx->getConstantUndef(Ty);
   for (SizeT I = 0; I < NumElements; ++I) {
     Constant *Index = Ctx->getConstantInt32(IceType_i32, I);
 
     // Extract the next two inputs.
-    Variable *Op0 = Func->makeVariable(ElementTy, Context.getNode());
+    Variable *Op0 = Func->makeVariable(ElementTy);
     lowerExtractElement(InstExtractElement::create(Func, Op0, Src0, Index));
-    Variable *Op1 = Func->makeVariable(ElementTy, Context.getNode());
+    Variable *Op1 = Func->makeVariable(ElementTy);
     lowerExtractElement(InstExtractElement::create(Func, Op1, Src1, Index));
 
     // Perform the arithmetic as a scalar operation.
-    Variable *Res = Func->makeVariable(ElementTy, Context.getNode());
+    Variable *Res = Func->makeVariable(ElementTy);
     lowerArithmetic(InstArithmetic::create(Func, Kind, Res, Op0, Op1));
 
     // Insert the result into position.
-    Variable *DestT = Func->makeVariable(Ty, Context.getNode());
+    Variable *DestT = Func->makeVariable(Ty);
     lowerInsertElement(InstInsertElement::create(Func, DestT, T, Res, Index));
     T = DestT;
     // TODO(stichnot): Use postLower() in -Om1 mode to avoid buildup of
     // infinite weight temporaries.
   }
 
   lowerAssign(InstAssign::create(Func, Dest, T));
 }
 
 // The following pattern occurs often in lowered C and C++ code:
@@ skipping 223 matching lines @@
              llvm::isa<ConstantRelocatable>(Offset));
     }
     Mem = OperandX8632Mem::create(Func, Ty, Base, Offset);
   }
   return llvm::cast<OperandX8632Mem>(legalize(Mem));
 }
 
 Variable *TargetX8632::makeReg(Type Type, int32_t RegNum) {
   // There aren't any 64-bit integer registers for x86-32.
   assert(Type != IceType_i64);
-  Variable *Reg = Func->makeVariable(Type, Context.getNode());
+  Variable *Reg = Func->makeVariable(Type);
   if (RegNum == Variable::NoRegister)
     Reg->setWeightInfinite();
   else
     Reg->setRegNum(RegNum);
   return Reg;
 }
 
 void TargetX8632::postLower() {
   if (Ctx->getOptLevel() != Opt_m1)
     return;
@@ skipping 214 matching lines @@
     Str << "\t.align\t" << Align << "\n";
     Str << MangledName << ":\n";
     for (SizeT i = 0; i < Size; ++i) {
       Str << "\t.byte\t" << (((unsigned)Data[i]) & 0xff) << "\n";
     }
     Str << "\t.size\t" << MangledName << ", " << Size << "\n";
   }
 }
 
 } // end of namespace Ice