//===- X86RegisterInfo.cpp - X86 Register Information -----------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file was developed by the LLVM research group and is distributed under // the University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains the X86 implementation of the MRegisterInfo class. This // file is responsible for the frame pointer elimination optimization on X86. // //===----------------------------------------------------------------------===// #include "X86.h" #include "X86RegisterInfo.h" #include "X86InstrBuilder.h" #include "llvm/Constants.h" #include "llvm/Type.h" #include "llvm/CodeGen/ValueTypes.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetFrameInfo.h" #include "Support/CommandLine.h" #include "Support/STLExtras.h" using namespace llvm; namespace { cl::opt NoFPElim("disable-fp-elim", cl::desc("Disable frame pointer elimination optimization")); cl::opt NoFusing("disable-spill-fusing", cl::desc("Disable fusing of spill code into instructions")); cl::opt PrintFailedFusing("print-failed-fuse-candidates", cl::desc("Print instructions that the allocator wants to" " fuse, but the X86 backend currently can't"), cl::Hidden); } X86RegisterInfo::X86RegisterInfo() : X86GenRegisterInfo(X86::ADJCALLSTACKDOWN, X86::ADJCALLSTACKUP) {} static unsigned getIdx(const TargetRegisterClass *RC) { switch (RC->getSize()) { default: assert(0 && "Invalid data size!"); case 1: return 0; case 2: return 1; case 4: return 2; case 10: return 3; } } int X86RegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned SrcReg, int FrameIdx, const TargetRegisterClass *RC) const { static const unsigned Opcode[] = { X86::MOVmr8, X86::MOVmr16, X86::MOVmr32, X86::FSTPr80 }; MachineInstr *I = addFrameReference(BuildMI(Opcode[getIdx(RC)], 5), FrameIdx).addReg(SrcReg); MBB.insert(MI, I); return 1; } int X86RegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned DestReg, int FrameIdx, const TargetRegisterClass *RC) const{ static const unsigned Opcode[] = { X86::MOVrm8, X86::MOVrm16, X86::MOVrm32, X86::FLDr80 }; unsigned OC = Opcode[getIdx(RC)]; MBB.insert(MI, addFrameReference(BuildMI(OC, 4, DestReg), FrameIdx)); return 1; } int X86RegisterInfo::copyRegToReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, unsigned DestReg, unsigned SrcReg, const TargetRegisterClass *RC) const { static const unsigned Opcode[] = { X86::MOVrr8, X86::MOVrr16, X86::MOVrr32, X86::FpMOV }; MBB.insert(MI, BuildMI(Opcode[getIdx(RC)],1,DestReg).addReg(SrcReg)); return 1; } static MachineInstr *MakeMInst(unsigned Opcode, unsigned FrameIndex, MachineInstr *MI) { return addFrameReference(BuildMI(Opcode, 4), FrameIndex); } static MachineInstr *MakeMRInst(unsigned Opcode, unsigned FrameIndex, MachineInstr *MI) { return addFrameReference(BuildMI(Opcode, 5), FrameIndex) .addReg(MI->getOperand(1).getReg()); } static MachineInstr *MakeMIInst(unsigned Opcode, unsigned FrameIndex, MachineInstr *MI) { if (MI->getOperand(1).isImmediate()) return addFrameReference(BuildMI(Opcode, 5), FrameIndex) .addZImm(MI->getOperand(1).getImmedValue()); else if (MI->getOperand(1).isGlobalAddress()) return addFrameReference(BuildMI(Opcode, 5), FrameIndex) .addGlobalAddress(MI->getOperand(1).getGlobal()); assert(0 && "Unknown operand for MakeMI!"); return 0; } static MachineInstr *MakeRMInst(unsigned Opcode, unsigned FrameIndex, MachineInstr *MI) { const MachineOperand& op = MI->getOperand(0); return addFrameReference(BuildMI(Opcode, 5, op.getReg(), op.getUseType()), FrameIndex); } static MachineInstr *MakeRMIInst(unsigned Opcode, unsigned FrameIndex, MachineInstr *MI) { const MachineOperand& op = MI->getOperand(0); return addFrameReference(BuildMI(Opcode, 5, op.getReg(), op.getUseType()), FrameIndex).addZImm(MI->getOperand(2).getImmedValue()); } bool X86RegisterInfo::foldMemoryOperand(MachineBasicBlock::iterator &MI, unsigned i, int FrameIndex) const { if (NoFusing) return false; /// FIXME: This should obviously be autogenerated by tablegen when patterns /// are available! MachineBasicBlock& MBB = *MI->getParent(); MachineInstr* NI = 0; if (i == 0) { switch(MI->getOpcode()) { case X86::XCHGrr8: NI = MakeMRInst(X86::XCHGmr8 ,FrameIndex, MI); break; case X86::XCHGrr16:NI = MakeMRInst(X86::XCHGmr16,FrameIndex, MI); break; case X86::XCHGrr32:NI = MakeMRInst(X86::XCHGmr32,FrameIndex, MI); break; case X86::MOVrr8: NI = MakeMRInst(X86::MOVmr8 , FrameIndex, MI); break; case X86::MOVrr16: NI = MakeMRInst(X86::MOVmr16, FrameIndex, MI); break; case X86::MOVrr32: NI = MakeMRInst(X86::MOVmr32, FrameIndex, MI); break; case X86::MOVri8: NI = MakeMIInst(X86::MOVmi8 , FrameIndex, MI); break; case X86::MOVri16: NI = MakeMIInst(X86::MOVmi16, FrameIndex, MI); break; case X86::MOVri32: NI = MakeMIInst(X86::MOVmi32, FrameIndex, MI); break; case X86::MULr8: NI = MakeMInst( X86::MULm8 , FrameIndex, MI); break; case X86::MULr16: NI = MakeMInst( X86::MULm16, FrameIndex, MI); break; case X86::MULr32: NI = MakeMInst( X86::MULm32, FrameIndex, MI); break; case X86::DIVr8: NI = MakeMInst( X86::DIVm8 , FrameIndex, MI); break; case X86::DIVr16: NI = MakeMInst( X86::DIVm16, FrameIndex, MI); break; case X86::DIVr32: NI = MakeMInst( X86::DIVm32, FrameIndex, MI); break; case X86::IDIVr8: NI = MakeMInst( X86::IDIVm8 , FrameIndex, MI); break; case X86::IDIVr16: NI = MakeMInst( X86::IDIVm16, FrameIndex, MI); break; case X86::IDIVr32: NI = MakeMInst( X86::IDIVm32, FrameIndex, MI); break; case X86::NEGr8: NI = MakeMInst( X86::NEGm8 , FrameIndex, MI); break; case X86::NEGr16: NI = MakeMInst( X86::NEGm16, FrameIndex, MI); break; case X86::NEGr32: NI = MakeMInst( X86::NEGm32, FrameIndex, MI); break; case X86::NOTr8: NI = MakeMInst( X86::NOTm8 , FrameIndex, MI); break; case X86::NOTr16: NI = MakeMInst( X86::NOTm16, FrameIndex, MI); break; case X86::NOTr32: NI = MakeMInst( X86::NOTm32, FrameIndex, MI); break; case X86::INCr8: NI = MakeMInst( X86::INCm8 , FrameIndex, MI); break; case X86::INCr16: NI = MakeMInst( X86::INCm16, FrameIndex, MI); break; case X86::INCr32: NI = MakeMInst( X86::INCm32, FrameIndex, MI); break; case X86::DECr8: NI = MakeMInst( X86::DECm8 , FrameIndex, MI); break; case X86::DECr16: NI = MakeMInst( X86::DECm16, FrameIndex, MI); break; case X86::DECr32: NI = MakeMInst( X86::DECm32, FrameIndex, MI); break; case X86::ADDrr8: NI = MakeMRInst(X86::ADDmr8 , FrameIndex, MI); break; case X86::ADDrr16: NI = MakeMRInst(X86::ADDmr16, FrameIndex, MI); break; case X86::ADDrr32: NI = MakeMRInst(X86::ADDmr32, FrameIndex, MI); break; case X86::ADCrr32: NI = MakeMRInst(X86::ADCmr32, FrameIndex, MI); break; case X86::ADDri8: NI = MakeMIInst(X86::ADDmi8 , FrameIndex, MI); break; case X86::ADDri16: NI = MakeMIInst(X86::ADDmi16, FrameIndex, MI); break; case X86::ADDri32: NI = MakeMIInst(X86::ADDmi32, FrameIndex, MI); break; case X86::SUBrr8: NI = MakeMRInst(X86::SUBmr8 , FrameIndex, MI); break; case X86::SUBrr16: NI = MakeMRInst(X86::SUBmr16, FrameIndex, MI); break; case X86::SUBrr32: NI = MakeMRInst(X86::SUBmr32, FrameIndex, MI); break; case X86::SBBrr32: NI = MakeMRInst(X86::SBBmr32, FrameIndex, MI); break; case X86::SUBri8: NI = MakeMIInst(X86::SUBmi8 , FrameIndex, MI); break; case X86::SUBri16: NI = MakeMIInst(X86::SUBmi16, FrameIndex, MI); break; case X86::SUBri32: NI = MakeMIInst(X86::SUBmi32, FrameIndex, MI); break; case X86::ANDrr8: NI = MakeMRInst(X86::ANDmr8 , FrameIndex, MI); break; case X86::ANDrr16: NI = MakeMRInst(X86::ANDmr16, FrameIndex, MI); break; case X86::ANDrr32: NI = MakeMRInst(X86::ANDmr32, FrameIndex, MI); break; case X86::ANDri8: NI = MakeMIInst(X86::ANDmi8 , FrameIndex, MI); break; case X86::ANDri16: NI = MakeMIInst(X86::ANDmi16, FrameIndex, MI); break; case X86::ANDri32: NI = MakeMIInst(X86::ANDmi32, FrameIndex, MI); break; case X86::ORrr8: NI = MakeMRInst(X86::ORmr8 , FrameIndex, MI); break; case X86::ORrr16: NI = MakeMRInst(X86::ORmr16, FrameIndex, MI); break; case X86::ORrr32: NI = MakeMRInst(X86::ORmr32, FrameIndex, MI); break; case X86::ORri8: NI = MakeMIInst(X86::ORmi8 , FrameIndex, MI); break; case X86::ORri16: NI = MakeMIInst(X86::ORmi16, FrameIndex, MI); break; case X86::ORri32: NI = MakeMIInst(X86::ORmi32, FrameIndex, MI); break; case X86::XORrr8: NI = MakeMRInst(X86::XORmr8 , FrameIndex, MI); break; case X86::XORrr16: NI = MakeMRInst(X86::XORmr16, FrameIndex, MI); break; case X86::XORrr32: NI = MakeMRInst(X86::XORmr32, FrameIndex, MI); break; case X86::XORri8: NI = MakeMIInst(X86::XORmi8 , FrameIndex, MI); break; case X86::XORri16: NI = MakeMIInst(X86::XORmi16, FrameIndex, MI); break; case X86::XORri32: NI = MakeMIInst(X86::XORmi32, FrameIndex, MI); break; case X86::SHLrCL8: NI = MakeMInst( X86::SHLmCL8 ,FrameIndex, MI); break; case X86::SHLrCL16:NI = MakeMInst( X86::SHLmCL16,FrameIndex, MI); break; case X86::SHLrCL32:NI = MakeMInst( X86::SHLmCL32,FrameIndex, MI); break; case X86::SHLri8: NI = MakeMIInst(X86::SHLmi8 , FrameIndex, MI); break; case X86::SHLri16: NI = MakeMIInst(X86::SHLmi16, FrameIndex, MI); break; case X86::SHLri32: NI = MakeMIInst(X86::SHLmi32, FrameIndex, MI); break; case X86::SHRrCL8: NI = MakeMInst( X86::SHRmCL8 ,FrameIndex, MI); break; case X86::SHRrCL16:NI = MakeMInst( X86::SHRmCL16,FrameIndex, MI); break; case X86::SHRrCL32:NI = MakeMInst( X86::SHRmCL32,FrameIndex, MI); break; case X86::SHRri8: NI = MakeMIInst(X86::SHRmi8 , FrameIndex, MI); break; case X86::SHRri16: NI = MakeMIInst(X86::SHRmi16, FrameIndex, MI); break; case X86::SHRri32: NI = MakeMIInst(X86::SHRmi32, FrameIndex, MI); break; case X86::SARrCL8: NI = MakeMInst( X86::SARmCL8 ,FrameIndex, MI); break; case X86::SARrCL16:NI = MakeMInst( X86::SARmCL16,FrameIndex, MI); break; case X86::SARrCL32:NI = MakeMInst( X86::SARmCL32,FrameIndex, MI); break; case X86::SARri8: NI = MakeMIInst(X86::SARmi8 , FrameIndex, MI); break; case X86::SARri16: NI = MakeMIInst(X86::SARmi16, FrameIndex, MI); break; case X86::SARri32: NI = MakeMIInst(X86::SARmi32, FrameIndex, MI); break; case X86::TESTrr8: NI = MakeMRInst(X86::TESTmr8 ,FrameIndex, MI); break; case X86::TESTrr16:NI = MakeMRInst(X86::TESTmr16,FrameIndex, MI); break; case X86::TESTrr32:NI = MakeMRInst(X86::TESTmr32,FrameIndex, MI); break; case X86::TESTri8: NI = MakeMIInst(X86::TESTmi8 ,FrameIndex, MI); break; case X86::TESTri16:NI = MakeMIInst(X86::TESTmi16,FrameIndex, MI); break; case X86::TESTri32:NI = MakeMIInst(X86::TESTmi32,FrameIndex, MI); break; case X86::CMPrr8: NI = MakeMRInst(X86::CMPmr8 , FrameIndex, MI); break; case X86::CMPrr16: NI = MakeMRInst(X86::CMPmr16, FrameIndex, MI); break; case X86::CMPrr32: NI = MakeMRInst(X86::CMPmr32, FrameIndex, MI); break; case X86::CMPri8: NI = MakeMIInst(X86::CMPmi8 , FrameIndex, MI); break; case X86::CMPri16: NI = MakeMIInst(X86::CMPmi16, FrameIndex, MI); break; case X86::CMPri32: NI = MakeMIInst(X86::CMPmi32, FrameIndex, MI); break; default: break; // Cannot fold } } else if (i == 1) { switch(MI->getOpcode()) { case X86::XCHGrr8: NI = MakeRMInst(X86::XCHGrm8 ,FrameIndex, MI); break; case X86::XCHGrr16:NI = MakeRMInst(X86::XCHGrm16,FrameIndex, MI); break; case X86::XCHGrr32:NI = MakeRMInst(X86::XCHGrm32,FrameIndex, MI); break; case X86::MOVrr8: NI = MakeRMInst(X86::MOVrm8 , FrameIndex, MI); break; case X86::MOVrr16: NI = MakeRMInst(X86::MOVrm16, FrameIndex, MI); break; case X86::MOVrr32: NI = MakeRMInst(X86::MOVrm32, FrameIndex, MI); break; case X86::ADDrr8: NI = MakeRMInst(X86::ADDrm8 , FrameIndex, MI); break; case X86::ADDrr16: NI = MakeRMInst(X86::ADDrm16, FrameIndex, MI); break; case X86::ADDrr32: NI = MakeRMInst(X86::ADDrm32, FrameIndex, MI); break; case X86::ADCrr32: NI = MakeRMInst(X86::ADCrm32, FrameIndex, MI); break; case X86::SUBrr8: NI = MakeRMInst(X86::SUBrm8 , FrameIndex, MI); break; case X86::SUBrr16: NI = MakeRMInst(X86::SUBrm16, FrameIndex, MI); break; case X86::SUBrr32: NI = MakeRMInst(X86::SUBrm32, FrameIndex, MI); break; case X86::SBBrr32: NI = MakeRMInst(X86::SBBrm32, FrameIndex, MI); break; case X86::ANDrr8: NI = MakeRMInst(X86::ANDrm8 , FrameIndex, MI); break; case X86::ANDrr16: NI = MakeRMInst(X86::ANDrm16, FrameIndex, MI); break; case X86::ANDrr32: NI = MakeRMInst(X86::ANDrm32, FrameIndex, MI); break; case X86::ORrr8: NI = MakeRMInst(X86::ORrm8 , FrameIndex, MI); break; case X86::ORrr16: NI = MakeRMInst(X86::ORrm16, FrameIndex, MI); break; case X86::ORrr32: NI = MakeRMInst(X86::ORrm32, FrameIndex, MI); break; case X86::XORrr8: NI = MakeRMInst(X86::XORrm8 , FrameIndex, MI); break; case X86::XORrr16: NI = MakeRMInst(X86::XORrm16, FrameIndex, MI); break; case X86::XORrr32: NI = MakeRMInst(X86::XORrm32, FrameIndex, MI); break; case X86::TESTrr8: NI = MakeRMInst(X86::TESTrm8 ,FrameIndex, MI); break; case X86::TESTrr16:NI = MakeRMInst(X86::TESTrm16,FrameIndex, MI); break; case X86::TESTrr32:NI = MakeRMInst(X86::TESTrm32,FrameIndex, MI); break; case X86::IMULrr16:NI = MakeRMInst(X86::IMULrm16,FrameIndex, MI); break; case X86::IMULrr32:NI = MakeRMInst(X86::IMULrm32,FrameIndex, MI); break; case X86::IMULrri16: NI = MakeRMIInst(X86::IMULrmi16, FrameIndex, MI);break; case X86::IMULrri32: NI = MakeRMIInst(X86::IMULrmi32, FrameIndex, MI);break; case X86::CMPrr8: NI = MakeRMInst(X86::CMPrm8 , FrameIndex, MI); break; case X86::CMPrr16: NI = MakeRMInst(X86::CMPrm16, FrameIndex, MI); break; case X86::CMPrr32: NI = MakeRMInst(X86::CMPrm32, FrameIndex, MI); break; case X86::MOVSXr16r8: NI = MakeRMInst(X86::MOVSXr16m8 , FrameIndex, MI); break; case X86::MOVSXr32r8: NI = MakeRMInst(X86::MOVSXr32m8, FrameIndex, MI); break; case X86::MOVSXr32r16:NI = MakeRMInst(X86::MOVSXr32m16, FrameIndex, MI); break; case X86::MOVZXr16r8: NI = MakeRMInst(X86::MOVZXr16m8 , FrameIndex, MI); break; case X86::MOVZXr32r8: NI = MakeRMInst(X86::MOVZXr32m8, FrameIndex, MI); break; case X86::MOVZXr32r16:NI = MakeRMInst(X86::MOVZXr32m16, FrameIndex, MI); break; default: break; } } if (NI) { MI = MBB.insert(MBB.erase(MI), NI); return true; } else { if (PrintFailedFusing) std::cerr << "We failed to fuse: " << *MI; return false; } } //===----------------------------------------------------------------------===// // Stack Frame Processing methods //===----------------------------------------------------------------------===// // hasFP - Return true if the specified function should have a dedicated frame // pointer register. This is true if the function has variable sized allocas or // if frame pointer elimination is disabled. // static bool hasFP(MachineFunction &MF) { return NoFPElim || MF.getFrameInfo()->hasVarSizedObjects(); } void X86RegisterInfo:: eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const { if (hasFP(MF)) { // If we have a frame pointer, turn the adjcallstackup instruction into a // 'sub ESP, ' and the adjcallstackdown instruction into 'add ESP, // ' MachineInstr *Old = I; unsigned Amount = Old->getOperand(0).getImmedValue(); if (Amount != 0) { // We need to keep the stack aligned properly. To do this, we round the // amount of space needed for the outgoing arguments up to the next // alignment boundary. unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment(); Amount = (Amount+Align-1)/Align*Align; MachineInstr *New; if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) { New=BuildMI(X86::SUBri32, 1, X86::ESP, MachineOperand::UseAndDef) .addZImm(Amount); } else { assert(Old->getOpcode() == X86::ADJCALLSTACKUP); New=BuildMI(X86::ADDri32, 1, X86::ESP, MachineOperand::UseAndDef) .addZImm(Amount); } // Replace the pseudo instruction with a new instruction... MBB.insert(I, New); } } MBB.erase(I); } void X86RegisterInfo::eliminateFrameIndex(MachineFunction &MF, MachineBasicBlock::iterator II) const { unsigned i = 0; MachineInstr &MI = *II; while (!MI.getOperand(i).isFrameIndex()) { ++i; assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!"); } int FrameIndex = MI.getOperand(i).getFrameIndex(); // This must be part of a four operand memory reference. Replace the // FrameIndex with base register with EBP. Add add an offset to the offset. MI.SetMachineOperandReg(i, hasFP(MF) ? X86::EBP : X86::ESP); // Now add the frame object offset to the offset from EBP. int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) + MI.getOperand(i+3).getImmedValue()+4; if (!hasFP(MF)) Offset += MF.getFrameInfo()->getStackSize(); else Offset += 4; // Skip the saved EBP MI.SetMachineOperandConst(i+3, MachineOperand::MO_SignExtendedImmed, Offset); } void X86RegisterInfo::processFunctionBeforeFrameFinalized(MachineFunction &MF) const{ if (hasFP(MF)) { // Create a frame entry for the EBP register that must be saved. int FrameIdx = MF.getFrameInfo()->CreateFixedObject(4, -8); assert(FrameIdx == MF.getFrameInfo()->getObjectIndexBegin() && "Slot for EBP register must be last in order to be found!"); } } void X86RegisterInfo::emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); MachineInstr *MI; // Get the number of bytes to allocate from the FrameInfo unsigned NumBytes = MFI->getStackSize(); if (hasFP(MF)) { // Get the offset of the stack slot for the EBP register... which is // guaranteed to be the last slot by processFunctionBeforeFrameFinalized. int EBPOffset = MFI->getObjectOffset(MFI->getObjectIndexBegin())+4; if (NumBytes) { // adjust stack pointer: ESP -= numbytes MI= BuildMI(X86::SUBri32, 1, X86::ESP, MachineOperand::UseAndDef) .addZImm(NumBytes); MBB.insert(MBBI, MI); } // Save EBP into the appropriate stack slot... MI = addRegOffset(BuildMI(X86::MOVmr32, 5), // mov [ESP-], EBP X86::ESP, EBPOffset+NumBytes).addReg(X86::EBP); MBB.insert(MBBI, MI); // Update EBP with the new base value... if (NumBytes == 4) // mov EBP, ESP MI = BuildMI(X86::MOVrr32, 2, X86::EBP).addReg(X86::ESP); else // lea EBP, [ESP+StackSize] MI = addRegOffset(BuildMI(X86::LEAr32, 5, X86::EBP), X86::ESP,NumBytes-4); MBB.insert(MBBI, MI); } else { if (MFI->hasCalls()) { // When we have no frame pointer, we reserve argument space for call sites // in the function immediately on entry to the current function. This // eliminates the need for add/sub ESP brackets around call sites. // NumBytes += MFI->getMaxCallFrameSize(); // Round the size to a multiple of the alignment (don't forget the 4 byte // offset though). unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment(); NumBytes = ((NumBytes+4)+Align-1)/Align*Align - 4; } // Update frame info to pretend that this is part of the stack... MFI->setStackSize(NumBytes); if (NumBytes) { // adjust stack pointer: ESP -= numbytes MI= BuildMI(X86::SUBri32, 1, X86::ESP, MachineOperand::UseAndDef) .addZImm(NumBytes); MBB.insert(MBBI, MI); } } } void X86RegisterInfo::emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const { const MachineFrameInfo *MFI = MF.getFrameInfo(); MachineBasicBlock::iterator MBBI = prior(MBB.end()); MachineInstr *MI; assert(MBBI->getOpcode() == X86::RET && "Can only insert epilog into returning blocks"); if (hasFP(MF)) { // Get the offset of the stack slot for the EBP register... which is // guaranteed to be the last slot by processFunctionBeforeFrameFinalized. int EBPOffset = MFI->getObjectOffset(MFI->getObjectIndexEnd()-1)+4; // mov ESP, EBP MI = BuildMI(X86::MOVrr32, 1,X86::ESP).addReg(X86::EBP); MBB.insert(MBBI, MI); // pop EBP MI = BuildMI(X86::POPr32, 0, X86::EBP); MBB.insert(MBBI, MI); } else { // Get the number of bytes allocated from the FrameInfo... unsigned NumBytes = MFI->getStackSize(); if (NumBytes) { // adjust stack pointer back: ESP += numbytes MI =BuildMI(X86::ADDri32, 1, X86::ESP, MachineOperand::UseAndDef) .addZImm(NumBytes); MBB.insert(MBBI, MI); } } } #include "X86GenRegisterInfo.inc" const TargetRegisterClass* X86RegisterInfo::getRegClassForType(const Type* Ty) const { switch (Ty->getPrimitiveID()) { case Type::LongTyID: case Type::ULongTyID: assert(0 && "Long values can't fit in registers!"); default: assert(0 && "Invalid type to getClass!"); case Type::BoolTyID: case Type::SByteTyID: case Type::UByteTyID: return &R8Instance; case Type::ShortTyID: case Type::UShortTyID: return &R16Instance; case Type::IntTyID: case Type::UIntTyID: case Type::PointerTyID: return &R32Instance; case Type::FloatTyID: case Type::DoubleTyID: return &RFPInstance; } }