--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Target/Mips/MipsFastISel.cpp	Mon Sep 08 22:06:00 2014 +0900
@@ -0,0 +1,409 @@
+//===-- MipsastISel.cpp - Mips FastISel implementation
+//---------------------===//
+
+#include "llvm/CodeGen/FunctionLoweringInfo.h"
+#include "llvm/CodeGen/FastISel.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/IR/GlobalAlias.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "MipsRegisterInfo.h"
+#include "MipsISelLowering.h"
+#include "MipsMachineFunction.h"
+#include "MipsSubtarget.h"
+#include "MipsTargetMachine.h"
+
+using namespace llvm;
+
+namespace {
+
+// All possible address modes.
+typedef struct Address {
+  enum { RegBase, FrameIndexBase } BaseType;
+
+  union {
+    unsigned Reg;
+    int FI;
+  } Base;
+
+  int64_t Offset;
+
+  // Innocuous defaults for our address.
+  Address() : BaseType(RegBase), Offset(0) { Base.Reg = 0; }
+} Address;
+
+class MipsFastISel final : public FastISel {
+
+  /// Subtarget - Keep a pointer to the MipsSubtarget around so that we can
+  /// make the right decision when generating code for different targets.
+  Module &M;
+  const TargetMachine &TM;
+  const TargetInstrInfo &TII;
+  const TargetLowering &TLI;
+  const MipsSubtarget *Subtarget;
+  MipsFunctionInfo *MFI;
+
+  // Convenience variables to avoid some queries.
+  LLVMContext *Context;
+
+  bool TargetSupported;
+
+public:
+  explicit MipsFastISel(FunctionLoweringInfo &funcInfo,
+                        const TargetLibraryInfo *libInfo)
+      : FastISel(funcInfo, libInfo),
+        M(const_cast<Module &>(*funcInfo.Fn->getParent())),
+        TM(funcInfo.MF->getTarget()),
+        TII(*TM.getSubtargetImpl()->getInstrInfo()),
+        TLI(*TM.getSubtargetImpl()->getTargetLowering()),
+        Subtarget(&TM.getSubtarget<MipsSubtarget>()) {
+    MFI = funcInfo.MF->getInfo<MipsFunctionInfo>();
+    Context = &funcInfo.Fn->getContext();
+    TargetSupported = ((Subtarget->getRelocationModel() == Reloc::PIC_) &&
+                       (Subtarget->hasMips32r2() && (Subtarget->isABI_O32())));
+  }
+
+  bool fastSelectInstruction(const Instruction *I) override;
+  unsigned fastMaterializeConstant(const Constant *C) override;
+
+  bool ComputeAddress(const Value *Obj, Address &Addr);
+
+private:
+  bool EmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
+                unsigned Alignment = 0);
+  bool EmitStore(MVT VT, unsigned SrcReg, Address &Addr,
+                 unsigned Alignment = 0);
+  bool SelectLoad(const Instruction *I);
+  bool SelectRet(const Instruction *I);
+  bool SelectStore(const Instruction *I);
+
+  bool isTypeLegal(Type *Ty, MVT &VT);
+  bool isLoadTypeLegal(Type *Ty, MVT &VT);
+
+  unsigned MaterializeFP(const ConstantFP *CFP, MVT VT);
+  unsigned MaterializeGV(const GlobalValue *GV, MVT VT);
+  unsigned MaterializeInt(const Constant *C, MVT VT);
+  unsigned Materialize32BitInt(int64_t Imm, const TargetRegisterClass *RC);
+
+  // for some reason, this default is not generated by tablegen
+  // so we explicitly generate it here.
+  //
+  unsigned fastEmitInst_riir(uint64_t inst, const TargetRegisterClass *RC,
+                             unsigned Op0, bool Op0IsKill, uint64_t imm1,
+                             uint64_t imm2, unsigned Op3, bool Op3IsKill) {
+    return 0;
+  }
+
+  MachineInstrBuilder EmitInst(unsigned Opc) {
+    return BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc));
+  }
+
+  MachineInstrBuilder EmitInst(unsigned Opc, unsigned DstReg) {
+    return BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc),
+                   DstReg);
+  }
+
+  MachineInstrBuilder EmitInstStore(unsigned Opc, unsigned SrcReg,
+                                    unsigned MemReg, int64_t MemOffset) {
+    return EmitInst(Opc).addReg(SrcReg).addReg(MemReg).addImm(MemOffset);
+  }
+
+  MachineInstrBuilder EmitInstLoad(unsigned Opc, unsigned DstReg,
+                                   unsigned MemReg, int64_t MemOffset) {
+    return EmitInst(Opc, DstReg).addReg(MemReg).addImm(MemOffset);
+  }
+
+#include "MipsGenFastISel.inc"
+};
+
+bool MipsFastISel::isTypeLegal(Type *Ty, MVT &VT) {
+  EVT evt = TLI.getValueType(Ty, true);
+  // Only handle simple types.
+  if (evt == MVT::Other || !evt.isSimple())
+    return false;
+  VT = evt.getSimpleVT();
+
+  // Handle all legal types, i.e. a register that will directly hold this
+  // value.
+  return TLI.isTypeLegal(VT);
+}
+
+bool MipsFastISel::isLoadTypeLegal(Type *Ty, MVT &VT) {
+  if (isTypeLegal(Ty, VT))
+    return true;
+  // We will extend this in a later patch:
+  //   If this is a type than can be sign or zero-extended to a basic operation
+  //   go ahead and accept it now.
+  if (VT == MVT::i8 || VT == MVT::i16)
+    return true;
+  return false;
+}
+
+bool MipsFastISel::ComputeAddress(const Value *Obj, Address &Addr) {
+  // This construct looks a big awkward but it is how other ports handle this
+  // and as this function is more fully completed, these cases which
+  // return false will have additional code in them.
+  //
+  if (isa<Instruction>(Obj))
+    return false;
+  else if (isa<ConstantExpr>(Obj))
+    return false;
+  Addr.Base.Reg = getRegForValue(Obj);
+  return Addr.Base.Reg != 0;
+}
+
+bool MipsFastISel::EmitLoad(MVT VT, unsigned &ResultReg, Address &Addr,
+                            unsigned Alignment) {
+  //
+  // more cases will be handled here in following patches.
+  //
+  unsigned Opc;
+  switch (VT.SimpleTy) {
+  case MVT::i32: {
+    ResultReg = createResultReg(&Mips::GPR32RegClass);
+    Opc = Mips::LW;
+    break;
+  }
+  case MVT::i16: {
+    ResultReg = createResultReg(&Mips::GPR32RegClass);
+    Opc = Mips::LHu;
+    break;
+  }
+  case MVT::i8: {
+    ResultReg = createResultReg(&Mips::GPR32RegClass);
+    Opc = Mips::LBu;
+    break;
+  }
+  case MVT::f32: {
+    ResultReg = createResultReg(&Mips::FGR32RegClass);
+    Opc = Mips::LWC1;
+    break;
+  }
+  case MVT::f64: {
+    ResultReg = createResultReg(&Mips::AFGR64RegClass);
+    Opc = Mips::LDC1;
+    break;
+  }
+  default:
+    return false;
+  }
+  EmitInstLoad(Opc, ResultReg, Addr.Base.Reg, Addr.Offset);
+  return true;
+}
+
+// Materialize a constant into a register, and return the register
+// number (or zero if we failed to handle it).
+unsigned MipsFastISel::fastMaterializeConstant(const Constant *C) {
+  EVT CEVT = TLI.getValueType(C->getType(), true);
+
+  // Only handle simple types.
+  if (!CEVT.isSimple())
+    return 0;
+  MVT VT = CEVT.getSimpleVT();
+
+  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C))
+    return MaterializeFP(CFP, VT);
+  else if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
+    return MaterializeGV(GV, VT);
+  else if (isa<ConstantInt>(C))
+    return MaterializeInt(C, VT);
+
+  return 0;
+}
+
+bool MipsFastISel::EmitStore(MVT VT, unsigned SrcReg, Address &Addr,
+                             unsigned Alignment) {
+  //
+  // more cases will be handled here in following patches.
+  //
+  unsigned Opc;
+  switch (VT.SimpleTy) {
+  case MVT::i8:
+    Opc = Mips::SB;
+    break;
+  case MVT::i16:
+    Opc = Mips::SH;
+    break;
+  case MVT::i32:
+    Opc = Mips::SW;
+    break;
+  case MVT::f32:
+    Opc = Mips::SWC1;
+    break;
+  case MVT::f64:
+    Opc = Mips::SDC1;
+    break;
+  default:
+    return false;
+  }
+  EmitInstStore(Opc, SrcReg, Addr.Base.Reg, Addr.Offset);
+  return true;
+}
+
+bool MipsFastISel::SelectLoad(const Instruction *I) {
+  // Atomic loads need special handling.
+  if (cast<LoadInst>(I)->isAtomic())
+    return false;
+
+  // Verify we have a legal type before going any further.
+  MVT VT;
+  if (!isLoadTypeLegal(I->getType(), VT))
+    return false;
+
+  // See if we can handle this address.
+  Address Addr;
+  if (!ComputeAddress(I->getOperand(0), Addr))
+    return false;
+
+  unsigned ResultReg;
+  if (!EmitLoad(VT, ResultReg, Addr, cast<LoadInst>(I)->getAlignment()))
+    return false;
+  updateValueMap(I, ResultReg);
+  return true;
+}
+
+bool MipsFastISel::SelectStore(const Instruction *I) {
+  Value *Op0 = I->getOperand(0);
+  unsigned SrcReg = 0;
+
+  // Atomic stores need special handling.
+  if (cast<StoreInst>(I)->isAtomic())
+    return false;
+
+  // Verify we have a legal type before going any further.
+  MVT VT;
+  if (!isLoadTypeLegal(I->getOperand(0)->getType(), VT))
+    return false;
+
+  // Get the value to be stored into a register.
+  SrcReg = getRegForValue(Op0);
+  if (SrcReg == 0)
+    return false;
+
+  // See if we can handle this address.
+  Address Addr;
+  if (!ComputeAddress(I->getOperand(1), Addr))
+    return false;
+
+  if (!EmitStore(VT, SrcReg, Addr, cast<StoreInst>(I)->getAlignment()))
+    return false;
+  return true;
+}
+
+bool MipsFastISel::SelectRet(const Instruction *I) {
+  const ReturnInst *Ret = cast<ReturnInst>(I);
+
+  if (!FuncInfo.CanLowerReturn)
+    return false;
+  if (Ret->getNumOperands() > 0) {
+    return false;
+  }
+  EmitInst(Mips::RetRA);
+  return true;
+}
+
+bool MipsFastISel::fastSelectInstruction(const Instruction *I) {
+  if (!TargetSupported)
+    return false;
+  switch (I->getOpcode()) {
+  default:
+    break;
+  case Instruction::Load:
+    return SelectLoad(I);
+  case Instruction::Store:
+    return SelectStore(I);
+  case Instruction::Ret:
+    return SelectRet(I);
+  }
+  return false;
+}
+}
+
+unsigned MipsFastISel::MaterializeFP(const ConstantFP *CFP, MVT VT) {
+  int64_t Imm = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
+  if (VT == MVT::f32) {
+    const TargetRegisterClass *RC = &Mips::FGR32RegClass;
+    unsigned DestReg = createResultReg(RC);
+    unsigned TempReg = Materialize32BitInt(Imm, &Mips::GPR32RegClass);
+    EmitInst(Mips::MTC1, DestReg).addReg(TempReg);
+    return DestReg;
+  } else if (VT == MVT::f64) {
+    const TargetRegisterClass *RC = &Mips::AFGR64RegClass;
+    unsigned DestReg = createResultReg(RC);
+    unsigned TempReg1 = Materialize32BitInt(Imm >> 32, &Mips::GPR32RegClass);
+    unsigned TempReg2 =
+        Materialize32BitInt(Imm & 0xFFFFFFFF, &Mips::GPR32RegClass);
+    EmitInst(Mips::BuildPairF64, DestReg).addReg(TempReg2).addReg(TempReg1);
+    return DestReg;
+  }
+  return 0;
+}
+
+unsigned MipsFastISel::MaterializeGV(const GlobalValue *GV, MVT VT) {
+  // For now 32-bit only.
+  if (VT != MVT::i32)
+    return 0;
+  const TargetRegisterClass *RC = &Mips::GPR32RegClass;
+  unsigned DestReg = createResultReg(RC);
+  const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
+  bool IsThreadLocal = GVar && GVar->isThreadLocal();
+  // TLS not supported at this time.
+  if (IsThreadLocal)
+    return 0;
+  EmitInst(Mips::LW, DestReg).addReg(MFI->getGlobalBaseReg()).addGlobalAddress(
+      GV, 0, MipsII::MO_GOT);
+  if ((GV->hasInternalLinkage() ||
+       (GV->hasLocalLinkage() && !isa<Function>(GV)))) {
+    unsigned TempReg = createResultReg(RC);
+    EmitInst(Mips::ADDiu, TempReg).addReg(DestReg).addGlobalAddress(
+        GV, 0, MipsII::MO_ABS_LO);
+    DestReg = TempReg;
+  }
+  return DestReg;
+}
+
+unsigned MipsFastISel::MaterializeInt(const Constant *C, MVT VT) {
+  if (VT != MVT::i32 && VT != MVT::i16 && VT != MVT::i8 && VT != MVT::i1)
+    return 0;
+  const TargetRegisterClass *RC = &Mips::GPR32RegClass;
+  const ConstantInt *CI = cast<ConstantInt>(C);
+  int64_t Imm;
+  if ((VT != MVT::i1) && CI->isNegative())
+    Imm = CI->getSExtValue();
+  else
+    Imm = CI->getZExtValue();
+  return Materialize32BitInt(Imm, RC);
+}
+
+unsigned MipsFastISel::Materialize32BitInt(int64_t Imm,
+                                           const TargetRegisterClass *RC) {
+  unsigned ResultReg = createResultReg(RC);
+
+  if (isInt<16>(Imm)) {
+    unsigned Opc = Mips::ADDiu;
+    EmitInst(Opc, ResultReg).addReg(Mips::ZERO).addImm(Imm);
+    return ResultReg;
+  } else if (isUInt<16>(Imm)) {
+    EmitInst(Mips::ORi, ResultReg).addReg(Mips::ZERO).addImm(Imm);
+    return ResultReg;
+  }
+  unsigned Lo = Imm & 0xFFFF;
+  unsigned Hi = (Imm >> 16) & 0xFFFF;
+  if (Lo) {
+    // Both Lo and Hi have nonzero bits.
+    unsigned TmpReg = createResultReg(RC);
+    EmitInst(Mips::LUi, TmpReg).addImm(Hi);
+    EmitInst(Mips::ORi, ResultReg).addReg(TmpReg).addImm(Lo);
+  } else {
+    EmitInst(Mips::LUi, ResultReg).addImm(Hi);
+  }
+  return ResultReg;
+}
+
+namespace llvm {
+FastISel *Mips::createFastISel(FunctionLoweringInfo &funcInfo,
+                               const TargetLibraryInfo *libInfo) {
+  return new MipsFastISel(funcInfo, libInfo);
+}
+}