//===- ARMBaseRegisterInfo.cpp - ARM Register Information -------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains the base ARM implementation of TargetRegisterInfo class. // //===----------------------------------------------------------------------===// #include "ARM.h" #include "ARMAddressingModes.h" #include "ARMBaseInstrInfo.h" #include "ARMBaseRegisterInfo.h" #include "ARMInstrInfo.h" #include "ARMMachineFunctionInfo.h" #include "ARMSubtarget.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" #include "llvm/Function.h" #include "llvm/LLVMContext.h" #include "llvm/CodeGen/MachineConstantPool.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineLocation.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/RegisterScavenging.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Target/TargetFrameInfo.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Target/TargetOptions.h" #include "llvm/ADT/BitVector.h" #include "llvm/ADT/SmallVector.h" using namespace llvm; unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum, bool *isSPVFP) { if (isSPVFP) *isSPVFP = false; using namespace ARM; switch (RegEnum) { default: llvm_unreachable("Unknown ARM register!"); case R0: case D0: case Q0: return 0; case R1: case D1: case Q1: return 1; case R2: case D2: case Q2: return 2; case R3: case D3: case Q3: return 3; case R4: case D4: case Q4: return 4; case R5: case D5: case Q5: return 5; case R6: case D6: case Q6: return 6; case R7: case D7: case Q7: return 7; case R8: case D8: case Q8: return 8; case R9: case D9: case Q9: return 9; case R10: case D10: case Q10: return 10; case R11: case D11: case Q11: return 11; case R12: case D12: case Q12: return 12; case SP: case D13: case Q13: return 13; case LR: case D14: case Q14: return 14; case PC: case D15: case Q15: return 15; case D16: return 16; case D17: return 17; case D18: return 18; case D19: return 19; case D20: return 20; case D21: return 21; case D22: return 22; case D23: return 23; case D24: return 24; case D25: return 25; case D26: return 27; case D27: return 27; case D28: return 28; case D29: return 29; case D30: return 30; case D31: return 31; case S0: case S1: case S2: case S3: case S4: case S5: case S6: case S7: case S8: case S9: case S10: case S11: case S12: case S13: case S14: case S15: case S16: case S17: case S18: case S19: case S20: case S21: case S22: case S23: case S24: case S25: case S26: case S27: case S28: case S29: case S30: case S31: { if (isSPVFP) *isSPVFP = true; switch (RegEnum) { default: return 0; // Avoid compile time warning. case S0: return 0; case S1: return 1; case S2: return 2; case S3: return 3; case S4: return 4; case S5: return 5; case S6: return 6; case S7: return 7; case S8: return 8; case S9: return 9; case S10: return 10; case S11: return 11; case S12: return 12; case S13: return 13; case S14: return 14; case S15: return 15; case S16: return 16; case S17: return 17; case S18: return 18; case S19: return 19; case S20: return 20; case S21: return 21; case S22: return 22; case S23: return 23; case S24: return 24; case S25: return 25; case S26: return 26; case S27: return 27; case S28: return 28; case S29: return 29; case S30: return 30; case S31: return 31; } } } } ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii, const ARMSubtarget &sti) : ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP), TII(tii), STI(sti), FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) { } const unsigned* ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const { static const unsigned CalleeSavedRegs[] = { ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8, ARM::R7, ARM::R6, ARM::R5, ARM::R4, ARM::D15, ARM::D14, ARM::D13, ARM::D12, ARM::D11, ARM::D10, ARM::D9, ARM::D8, 0 }; static const unsigned DarwinCalleeSavedRegs[] = { // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved // register. ARM::LR, ARM::R7, ARM::R6, ARM::R5, ARM::R4, ARM::R11, ARM::R10, ARM::R8, ARM::D15, ARM::D14, ARM::D13, ARM::D12, ARM::D11, ARM::D10, ARM::D9, ARM::D8, 0 }; return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs; } const TargetRegisterClass* const * ARMBaseRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const { static const TargetRegisterClass * const CalleeSavedRegClasses[] = { &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, 0 }; static const TargetRegisterClass * const ThumbCalleeSavedRegClasses[] = { &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass,&ARM::tGPRRegClass,&ARM::tGPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, 0 }; static const TargetRegisterClass * const DarwinCalleeSavedRegClasses[] = { &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, 0 }; static const TargetRegisterClass * const DarwinThumbCalleeSavedRegClasses[] ={ &ARM::GPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::tGPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::GPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, &ARM::DPRRegClass, 0 }; if (STI.isThumb1Only()) { return STI.isTargetDarwin() ? DarwinThumbCalleeSavedRegClasses : ThumbCalleeSavedRegClasses; } return STI.isTargetDarwin() ? DarwinCalleeSavedRegClasses : CalleeSavedRegClasses; } BitVector ARMBaseRegisterInfo::getReservedRegs(const MachineFunction &MF) const { // FIXME: avoid re-calculating this everytime. BitVector Reserved(getNumRegs()); Reserved.set(ARM::SP); Reserved.set(ARM::PC); if (STI.isTargetDarwin() || hasFP(MF)) Reserved.set(FramePtr); // Some targets reserve R9. if (STI.isR9Reserved()) Reserved.set(ARM::R9); return Reserved; } bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF, unsigned Reg) const { switch (Reg) { default: break; case ARM::SP: case ARM::PC: return true; case ARM::R7: case ARM::R11: if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF))) return true; break; case ARM::R9: return STI.isR9Reserved(); } return false; } const TargetRegisterClass * ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const { return &ARM::GPRRegClass; } /// getAllocationOrder - Returns the register allocation order for a specified /// register class in the form of a pair of TargetRegisterClass iterators. std::pair ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC, unsigned HintType, unsigned HintReg, const MachineFunction &MF) const { // Alternative register allocation orders when favoring even / odd registers // of register pairs. // No FP, R9 is available. static const unsigned GPREven1[] = { ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10, ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R9, ARM::R11 }; static const unsigned GPROdd1[] = { ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11, ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8, ARM::R10 }; // FP is R7, R9 is available. static const unsigned GPREven2[] = { ARM::R0, ARM::R2, ARM::R4, ARM::R8, ARM::R10, ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R9, ARM::R11 }; static const unsigned GPROdd2[] = { ARM::R1, ARM::R3, ARM::R5, ARM::R9, ARM::R11, ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8, ARM::R10 }; // FP is R11, R9 is available. static const unsigned GPREven3[] = { ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R9 }; static const unsigned GPROdd3[] = { ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9, ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7, ARM::R8 }; // No FP, R9 is not available. static const unsigned GPREven4[] = { ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R10, ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8, ARM::R11 }; static const unsigned GPROdd4[] = { ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R11, ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8, ARM::R10 }; // FP is R7, R9 is not available. static const unsigned GPREven5[] = { ARM::R0, ARM::R2, ARM::R4, ARM::R10, ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8, ARM::R11 }; static const unsigned GPROdd5[] = { ARM::R1, ARM::R3, ARM::R5, ARM::R11, ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8, ARM::R10 }; // FP is R11, R9 is not available. static const unsigned GPREven6[] = { ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8 }; static const unsigned GPROdd6[] = { ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8 }; if (HintType == ARMRI::RegPairEven) { if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0) // It's no longer possible to fulfill this hint. Return the default // allocation order. return std::make_pair(RC->allocation_order_begin(MF), RC->allocation_order_end(MF)); if (!STI.isTargetDarwin() && !hasFP(MF)) { if (!STI.isR9Reserved()) return std::make_pair(GPREven1, GPREven1 + (sizeof(GPREven1)/sizeof(unsigned))); else return std::make_pair(GPREven4, GPREven4 + (sizeof(GPREven4)/sizeof(unsigned))); } else if (FramePtr == ARM::R7) { if (!STI.isR9Reserved()) return std::make_pair(GPREven2, GPREven2 + (sizeof(GPREven2)/sizeof(unsigned))); else return std::make_pair(GPREven5, GPREven5 + (sizeof(GPREven5)/sizeof(unsigned))); } else { // FramePtr == ARM::R11 if (!STI.isR9Reserved()) return std::make_pair(GPREven3, GPREven3 + (sizeof(GPREven3)/sizeof(unsigned))); else return std::make_pair(GPREven6, GPREven6 + (sizeof(GPREven6)/sizeof(unsigned))); } } else if (HintType == ARMRI::RegPairOdd) { if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0) // It's no longer possible to fulfill this hint. Return the default // allocation order. return std::make_pair(RC->allocation_order_begin(MF), RC->allocation_order_end(MF)); if (!STI.isTargetDarwin() && !hasFP(MF)) { if (!STI.isR9Reserved()) return std::make_pair(GPROdd1, GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned))); else return std::make_pair(GPROdd4, GPROdd4 + (sizeof(GPROdd4)/sizeof(unsigned))); } else if (FramePtr == ARM::R7) { if (!STI.isR9Reserved()) return std::make_pair(GPROdd2, GPROdd2 + (sizeof(GPROdd2)/sizeof(unsigned))); else return std::make_pair(GPROdd5, GPROdd5 + (sizeof(GPROdd5)/sizeof(unsigned))); } else { // FramePtr == ARM::R11 if (!STI.isR9Reserved()) return std::make_pair(GPROdd3, GPROdd3 + (sizeof(GPROdd3)/sizeof(unsigned))); else return std::make_pair(GPROdd6, GPROdd6 + (sizeof(GPROdd6)/sizeof(unsigned))); } } return std::make_pair(RC->allocation_order_begin(MF), RC->allocation_order_end(MF)); } /// ResolveRegAllocHint - Resolves the specified register allocation hint /// to a physical register. Returns the physical register if it is successful. unsigned ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg, const MachineFunction &MF) const { if (Reg == 0 || !isPhysicalRegister(Reg)) return 0; if (Type == 0) return Reg; else if (Type == (unsigned)ARMRI::RegPairOdd) // Odd register. return getRegisterPairOdd(Reg, MF); else if (Type == (unsigned)ARMRI::RegPairEven) // Even register. return getRegisterPairEven(Reg, MF); return 0; } void ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg, MachineFunction &MF) const { MachineRegisterInfo *MRI = &MF.getRegInfo(); std::pair Hint = MRI->getRegAllocationHint(Reg); if ((Hint.first == (unsigned)ARMRI::RegPairOdd || Hint.first == (unsigned)ARMRI::RegPairEven) && Hint.second && TargetRegisterInfo::isVirtualRegister(Hint.second)) { // If 'Reg' is one of the even / odd register pair and it's now changed // (e.g. coalesced) into a different register. The other register of the // pair allocation hint must be updated to reflect the relationship // change. unsigned OtherReg = Hint.second; Hint = MRI->getRegAllocationHint(OtherReg); if (Hint.second == Reg) // Make sure the pair has not already divorced. MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg); } } /// 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. /// bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const { const MachineFrameInfo *MFI = MF.getFrameInfo(); return (NoFramePointerElim || MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()); } /// estimateStackSize - Estimate and return the size of the frame. static unsigned estimateStackSize(MachineFunction &MF, MachineFrameInfo *MFI) { const MachineFrameInfo *FFI = MF.getFrameInfo(); int Offset = 0; for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) { int FixedOff = -FFI->getObjectOffset(i); if (FixedOff > Offset) Offset = FixedOff; } for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) { if (FFI->isDeadObjectIndex(i)) continue; Offset += FFI->getObjectSize(i); unsigned Align = FFI->getObjectAlignment(i); // Adjust to alignment boundary Offset = (Offset+Align-1)/Align*Align; } return (unsigned)Offset; } /// estimateRSStackSizeLimit - Look at each instruction that references stack /// frames and return the stack size limit beyond which some of these /// instructions will require scratch register during their expansion later. unsigned ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const { unsigned Limit = (1 << 12) - 1; for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) { for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { if (!I->getOperand(i).isFI()) continue; const TargetInstrDesc &Desc = TII.get(I->getOpcode()); unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask); if (AddrMode == ARMII::AddrMode3 || AddrMode == ARMII::AddrModeT2_i8) return (1 << 8) - 1; if (AddrMode == ARMII::AddrMode5 || AddrMode == ARMII::AddrModeT2_i8s4) Limit = std::min(Limit, ((1U << 8) - 1) * 4); if (AddrMode == ARMII::AddrModeT2_i12 && hasFP(MF)) // When the stack offset is negative, we will end up using // the i8 instructions instead. return (1 << 8) - 1; break; // At most one FI per instruction } } } return Limit; } void ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, RegScavenger *RS) const { // This tells PEI to spill the FP as if it is any other callee-save register // to take advantage the eliminateFrameIndex machinery. This also ensures it // is spilled in the order specified by getCalleeSavedRegs() to make it easier // to combine multiple loads / stores. bool CanEliminateFrame = true; bool CS1Spilled = false; bool LRSpilled = false; unsigned NumGPRSpills = 0; SmallVector UnspilledCS1GPRs; SmallVector UnspilledCS2GPRs; ARMFunctionInfo *AFI = MF.getInfo(); // Don't spill FP if the frame can be eliminated. This is determined // by scanning the callee-save registers to see if any is used. const unsigned *CSRegs = getCalleeSavedRegs(); const TargetRegisterClass* const *CSRegClasses = getCalleeSavedRegClasses(); for (unsigned i = 0; CSRegs[i]; ++i) { unsigned Reg = CSRegs[i]; bool Spilled = false; if (MF.getRegInfo().isPhysRegUsed(Reg)) { AFI->setCSRegisterIsSpilled(Reg); Spilled = true; CanEliminateFrame = false; } else { // Check alias registers too. for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) { if (MF.getRegInfo().isPhysRegUsed(*Aliases)) { Spilled = true; CanEliminateFrame = false; } } } if (CSRegClasses[i] == &ARM::GPRRegClass) { if (Spilled) { NumGPRSpills++; if (!STI.isTargetDarwin()) { if (Reg == ARM::LR) LRSpilled = true; CS1Spilled = true; continue; } // Keep track if LR and any of R4, R5, R6, and R7 is spilled. switch (Reg) { case ARM::LR: LRSpilled = true; // Fallthrough case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: CS1Spilled = true; break; default: break; } } else { if (!STI.isTargetDarwin()) { UnspilledCS1GPRs.push_back(Reg); continue; } switch (Reg) { case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: UnspilledCS1GPRs.push_back(Reg); break; default: UnspilledCS2GPRs.push_back(Reg); break; } } } } bool ForceLRSpill = false; if (!LRSpilled && AFI->isThumb1OnlyFunction()) { unsigned FnSize = TII.GetFunctionSizeInBytes(MF); // Force LR to be spilled if the Thumb function size is > 2048. This enables // use of BL to implement far jump. If it turns out that it's not needed // then the branch fix up path will undo it. if (FnSize >= (1 << 11)) { CanEliminateFrame = false; ForceLRSpill = true; } } bool ExtraCSSpill = false; if (!CanEliminateFrame || hasFP(MF)) { AFI->setHasStackFrame(true); // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled. // Spill LR as well so we can fold BX_RET to the registers restore (LDM). if (!LRSpilled && CS1Spilled) { MF.getRegInfo().setPhysRegUsed(ARM::LR); AFI->setCSRegisterIsSpilled(ARM::LR); NumGPRSpills++; UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(), UnspilledCS1GPRs.end(), (unsigned)ARM::LR)); ForceLRSpill = false; ExtraCSSpill = true; } // Darwin ABI requires FP to point to the stack slot that contains the // previous FP. if (STI.isTargetDarwin() || hasFP(MF)) { MF.getRegInfo().setPhysRegUsed(FramePtr); NumGPRSpills++; } // If stack and double are 8-byte aligned and we are spilling an odd number // of GPRs. Spill one extra callee save GPR so we won't have to pad between // the integer and double callee save areas. unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment(); if (TargetAlign == 8 && (NumGPRSpills & 1)) { if (CS1Spilled && !UnspilledCS1GPRs.empty()) { for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) { unsigned Reg = UnspilledCS1GPRs[i]; // Don't spill high register if the function is thumb1 if (!AFI->isThumb1OnlyFunction() || isARMLowRegister(Reg) || Reg == ARM::LR) { MF.getRegInfo().setPhysRegUsed(Reg); AFI->setCSRegisterIsSpilled(Reg); if (!isReservedReg(MF, Reg)) ExtraCSSpill = true; break; } } } else if (!UnspilledCS2GPRs.empty() && !AFI->isThumb1OnlyFunction()) { unsigned Reg = UnspilledCS2GPRs.front(); MF.getRegInfo().setPhysRegUsed(Reg); AFI->setCSRegisterIsSpilled(Reg); if (!isReservedReg(MF, Reg)) ExtraCSSpill = true; } } // Estimate if we might need to scavenge a register at some point in order // to materialize a stack offset. If so, either spill one additional // callee-saved register or reserve a special spill slot to facilitate // register scavenging. if (RS && !ExtraCSSpill && !AFI->isThumb1OnlyFunction()) { MachineFrameInfo *MFI = MF.getFrameInfo(); if (estimateStackSize(MF, MFI) >= estimateRSStackSizeLimit(MF)) { // If any non-reserved CS register isn't spilled, just spill one or two // extra. That should take care of it! unsigned NumExtras = TargetAlign / 4; SmallVector Extras; while (NumExtras && !UnspilledCS1GPRs.empty()) { unsigned Reg = UnspilledCS1GPRs.back(); UnspilledCS1GPRs.pop_back(); if (!isReservedReg(MF, Reg)) { Extras.push_back(Reg); NumExtras--; } } while (NumExtras && !UnspilledCS2GPRs.empty()) { unsigned Reg = UnspilledCS2GPRs.back(); UnspilledCS2GPRs.pop_back(); if (!isReservedReg(MF, Reg)) { Extras.push_back(Reg); NumExtras--; } } if (Extras.size() && NumExtras == 0) { for (unsigned i = 0, e = Extras.size(); i != e; ++i) { MF.getRegInfo().setPhysRegUsed(Extras[i]); AFI->setCSRegisterIsSpilled(Extras[i]); } } else { // Reserve a slot closest to SP or frame pointer. const TargetRegisterClass *RC = &ARM::GPRRegClass; RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(), RC->getAlignment())); } } } } if (ForceLRSpill) { MF.getRegInfo().setPhysRegUsed(ARM::LR); AFI->setCSRegisterIsSpilled(ARM::LR); AFI->setLRIsSpilledForFarJump(true); } } unsigned ARMBaseRegisterInfo::getRARegister() const { return ARM::LR; } unsigned ARMBaseRegisterInfo::getFrameRegister(MachineFunction &MF) const { if (STI.isTargetDarwin() || hasFP(MF)) return FramePtr; return ARM::SP; } unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const { llvm_unreachable("What is the exception register"); return 0; } unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const { llvm_unreachable("What is the exception handler register"); return 0; } int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const { return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0); } unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg, const MachineFunction &MF) const { switch (Reg) { default: break; // Return 0 if either register of the pair is a special register. // So no R12, etc. case ARM::R1: return ARM::R0; case ARM::R3: // FIXME! return STI.isThumb1Only() ? 0 : ARM::R2; case ARM::R5: return ARM::R4; case ARM::R7: return isReservedReg(MF, ARM::R7) ? 0 : ARM::R6; case ARM::R9: return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8; case ARM::R11: return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10; case ARM::S1: return ARM::S0; case ARM::S3: return ARM::S2; case ARM::S5: return ARM::S4; case ARM::S7: return ARM::S6; case ARM::S9: return ARM::S8; case ARM::S11: return ARM::S10; case ARM::S13: return ARM::S12; case ARM::S15: return ARM::S14; case ARM::S17: return ARM::S16; case ARM::S19: return ARM::S18; case ARM::S21: return ARM::S20; case ARM::S23: return ARM::S22; case ARM::S25: return ARM::S24; case ARM::S27: return ARM::S26; case ARM::S29: return ARM::S28; case ARM::S31: return ARM::S30; case ARM::D1: return ARM::D0; case ARM::D3: return ARM::D2; case ARM::D5: return ARM::D4; case ARM::D7: return ARM::D6; case ARM::D9: return ARM::D8; case ARM::D11: return ARM::D10; case ARM::D13: return ARM::D12; case ARM::D15: return ARM::D14; case ARM::D17: return ARM::D16; case ARM::D19: return ARM::D18; case ARM::D21: return ARM::D20; case ARM::D23: return ARM::D22; case ARM::D25: return ARM::D24; case ARM::D27: return ARM::D26; case ARM::D29: return ARM::D28; case ARM::D31: return ARM::D30; } return 0; } unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg, const MachineFunction &MF) const { switch (Reg) { default: break; // Return 0 if either register of the pair is a special register. // So no R12, etc. case ARM::R0: return ARM::R1; case ARM::R2: // FIXME! return STI.isThumb1Only() ? 0 : ARM::R3; case ARM::R4: return ARM::R5; case ARM::R6: return isReservedReg(MF, ARM::R7) ? 0 : ARM::R7; case ARM::R8: return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9; case ARM::R10: return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11; case ARM::S0: return ARM::S1; case ARM::S2: return ARM::S3; case ARM::S4: return ARM::S5; case ARM::S6: return ARM::S7; case ARM::S8: return ARM::S9; case ARM::S10: return ARM::S11; case ARM::S12: return ARM::S13; case ARM::S14: return ARM::S15; case ARM::S16: return ARM::S17; case ARM::S18: return ARM::S19; case ARM::S20: return ARM::S21; case ARM::S22: return ARM::S23; case ARM::S24: return ARM::S25; case ARM::S26: return ARM::S27; case ARM::S28: return ARM::S29; case ARM::S30: return ARM::S31; case ARM::D0: return ARM::D1; case ARM::D2: return ARM::D3; case ARM::D4: return ARM::D5; case ARM::D6: return ARM::D7; case ARM::D8: return ARM::D9; case ARM::D10: return ARM::D11; case ARM::D12: return ARM::D13; case ARM::D14: return ARM::D15; case ARM::D16: return ARM::D17; case ARM::D18: return ARM::D19; case ARM::D20: return ARM::D21; case ARM::D22: return ARM::D23; case ARM::D24: return ARM::D25; case ARM::D26: return ARM::D27; case ARM::D28: return ARM::D29; case ARM::D30: return ARM::D31; } return 0; } /// emitLoadConstPool - Emits a load from constpool to materialize the /// specified immediate. void ARMBaseRegisterInfo:: emitLoadConstPool(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, DebugLoc dl, unsigned DestReg, unsigned SubIdx, int Val, ARMCC::CondCodes Pred, unsigned PredReg) const { MachineFunction &MF = *MBB.getParent(); MachineConstantPool *ConstantPool = MF.getConstantPool(); Constant *C = ConstantInt::get(Type::Int32Ty, Val); unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4); BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp)) .addReg(DestReg, getDefRegState(true), SubIdx) .addConstantPoolIndex(Idx) .addReg(0).addImm(0).addImm(Pred).addReg(PredReg); } bool ARMBaseRegisterInfo:: requiresRegisterScavenging(const MachineFunction &MF) const { return true; } // hasReservedCallFrame - Under normal circumstances, when a frame pointer is // not required, we reserve argument space for call sites in the function // immediately on entry to the current function. This eliminates the need for // add/sub sp brackets around call sites. Returns true if the call frame is // included as part of the stack frame. bool ARMBaseRegisterInfo:: hasReservedCallFrame(MachineFunction &MF) const { const MachineFrameInfo *FFI = MF.getFrameInfo(); unsigned CFSize = FFI->getMaxCallFrameSize(); // It's not always a good idea to include the call frame as part of the // stack frame. ARM (especially Thumb) has small immediate offset to // address the stack frame. So a large call frame can cause poor codegen // and may even makes it impossible to scavenge a register. if (CFSize >= ((1 << 12) - 1) / 2) // Half of imm12 return false; return !MF.getFrameInfo()->hasVarSizedObjects(); } static void emitSPUpdate(bool isARM, MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, DebugLoc dl, const ARMBaseInstrInfo &TII, int NumBytes, ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) { if (isARM) emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes, Pred, PredReg, TII); else emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes, Pred, PredReg, TII); } void ARMBaseRegisterInfo:: eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const { if (!hasReservedCallFrame(MF)) { // If we have alloca, convert as follows: // ADJCALLSTACKDOWN -> sub, sp, sp, amount // ADJCALLSTACKUP -> add, sp, sp, amount MachineInstr *Old = I; DebugLoc dl = Old->getDebugLoc(); unsigned Amount = Old->getOperand(0).getImm(); 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; ARMFunctionInfo *AFI = MF.getInfo(); assert(!AFI->isThumb1OnlyFunction() && "This eliminateCallFramePseudoInstr does not suppor Thumb1!"); bool isARM = !AFI->isThumbFunction(); // Replace the pseudo instruction with a new instruction... unsigned Opc = Old->getOpcode(); ARMCC::CondCodes Pred = (ARMCC::CondCodes)Old->getOperand(1).getImm(); // FIXME: Thumb2 version of ADJCALLSTACKUP and ADJCALLSTACKDOWN? if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) { // Note: PredReg is operand 2 for ADJCALLSTACKDOWN. unsigned PredReg = Old->getOperand(2).getReg(); emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg); } else { // Note: PredReg is operand 3 for ADJCALLSTACKUP. unsigned PredReg = Old->getOperand(3).getReg(); assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP); emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg); } } } MBB.erase(I); } /// findScratchRegister - Find a 'free' ARM register. If register scavenger /// is not being used, R12 is available. Otherwise, try for a call-clobbered /// register first and then a spilled callee-saved register if that fails. static unsigned findScratchRegister(RegScavenger *RS, const TargetRegisterClass *RC, ARMFunctionInfo *AFI) { unsigned Reg = RS ? RS->FindUnusedReg(RC, true) : (unsigned) ARM::R12; assert(!AFI->isThumb1OnlyFunction()); if (Reg == 0) // Try a already spilled CS register. Reg = RS->FindUnusedReg(RC, AFI->getSpilledCSRegisters()); return Reg; } void ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj, RegScavenger *RS) const { unsigned i = 0; MachineInstr &MI = *II; MachineBasicBlock &MBB = *MI.getParent(); MachineFunction &MF = *MBB.getParent(); ARMFunctionInfo *AFI = MF.getInfo(); assert(!AFI->isThumb1OnlyFunction() && "This eliminateFrameIndex does not suppor Thumb1!"); while (!MI.getOperand(i).isFI()) { ++i; assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!"); } unsigned FrameReg = ARM::SP; int FrameIndex = MI.getOperand(i).getIndex(); int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) + MF.getFrameInfo()->getStackSize() + SPAdj; if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex)) Offset -= AFI->getGPRCalleeSavedArea1Offset(); else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex)) Offset -= AFI->getGPRCalleeSavedArea2Offset(); else if (AFI->isDPRCalleeSavedAreaFrame(FrameIndex)) Offset -= AFI->getDPRCalleeSavedAreaOffset(); else if (hasFP(MF)) { assert(SPAdj == 0 && "Unexpected"); // There is alloca()'s in this function, must reference off the frame // pointer instead. FrameReg = getFrameRegister(MF); Offset -= AFI->getFramePtrSpillOffset(); } // modify MI as necessary to handle as much of 'Offset' as possible if (!AFI->isThumbFunction()) Offset = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII); else { assert(AFI->isThumb2Function()); Offset = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII); } if (Offset == 0) return; // If we get here, the immediate doesn't fit into the instruction. We folded // as much as possible above, handle the rest, providing a register that is // SP+LargeImm. assert(Offset && "This code isn't needed if offset already handled!"); // Insert a set of r12 with the full address: r12 = sp + offset // If the offset we have is too large to fit into the instruction, we need // to form it with a series of ADDri's. Do this by taking 8-bit chunks // out of 'Offset'. unsigned ScratchReg = findScratchRegister(RS, &ARM::GPRRegClass, AFI); if (ScratchReg == 0) // No register is "free". Scavenge a register. ScratchReg = RS->scavengeRegister(&ARM::GPRRegClass, II, SPAdj); int PIdx = MI.findFirstPredOperandIdx(); ARMCC::CondCodes Pred = (PIdx == -1) ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm(); unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg(); if (!AFI->isThumbFunction()) emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg, Offset, Pred, PredReg, TII); else { assert(AFI->isThumb2Function()); emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg, Offset, Pred, PredReg, TII); } MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true); } /// Move iterator pass the next bunch of callee save load / store ops for /// the particular spill area (1: integer area 1, 2: integer area 2, /// 3: fp area, 0: don't care). static void movePastCSLoadStoreOps(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, int Opc1, int Opc2, unsigned Area, const ARMSubtarget &STI) { while (MBBI != MBB.end() && ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) && MBBI->getOperand(1).isFI()) { if (Area != 0) { bool Done = false; unsigned Category = 0; switch (MBBI->getOperand(0).getReg()) { case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: Category = 1; break; case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: Category = STI.isTargetDarwin() ? 2 : 1; break; case ARM::D8: case ARM::D9: case ARM::D10: case ARM::D11: case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15: Category = 3; break; default: Done = true; break; } if (Done || Category != Area) break; } ++MBBI; } } void ARMBaseRegisterInfo:: emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo(); assert(!AFI->isThumb1OnlyFunction() && "This emitPrologue does not suppor Thumb1!"); bool isARM = !AFI->isThumbFunction(); unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); unsigned NumBytes = MFI->getStackSize(); const std::vector &CSI = MFI->getCalleeSavedInfo(); DebugLoc dl = (MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc::getUnknownLoc()); // Determine the sizes of each callee-save spill areas and record which frame // belongs to which callee-save spill areas. unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0; int FramePtrSpillFI = 0; if (VARegSaveSize) emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize); if (!AFI->hasStackFrame()) { if (NumBytes != 0) emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes); return; } for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); int FI = CSI[i].getFrameIdx(); switch (Reg) { case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: if (Reg == FramePtr) FramePtrSpillFI = FI; AFI->addGPRCalleeSavedArea1Frame(FI); GPRCS1Size += 4; break; case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: if (Reg == FramePtr) FramePtrSpillFI = FI; if (STI.isTargetDarwin()) { AFI->addGPRCalleeSavedArea2Frame(FI); GPRCS2Size += 4; } else { AFI->addGPRCalleeSavedArea1Frame(FI); GPRCS1Size += 4; } break; default: AFI->addDPRCalleeSavedAreaFrame(FI); DPRCSSize += 8; } } // Build the new SUBri to adjust SP for integer callee-save spill area 1. emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size); movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI); // Darwin ABI requires FP to point to the stack slot that contains the // previous FP. if (STI.isTargetDarwin() || hasFP(MF)) { unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri; MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr) .addFrameIndex(FramePtrSpillFI).addImm(0); AddDefaultCC(AddDefaultPred(MIB)); } // Build the new SUBri to adjust SP for integer callee-save spill area 2. emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size); // Build the new SUBri to adjust SP for FP callee-save spill area. movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI); emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize); // Determine starting offsets of spill areas. unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize); unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes); AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset); AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset); AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset); NumBytes = DPRCSOffset; if (NumBytes) { // Insert it after all the callee-save spills. movePastCSLoadStoreOps(MBB, MBBI, ARM::FSTD, 0, 3, STI); emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes); } if (STI.isTargetELF() && hasFP(MF)) { MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - AFI->getFramePtrSpillOffset()); } AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); } static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) { for (unsigned i = 0; CSRegs[i]; ++i) if (Reg == CSRegs[i]) return true; return false; } static bool isCSRestore(MachineInstr *MI, const ARMBaseInstrInfo &TII, const unsigned *CSRegs) { return ((MI->getOpcode() == (int)ARM::FLDD || MI->getOpcode() == (int)ARM::LDR || MI->getOpcode() == (int)ARM::t2LDRi12) && MI->getOperand(1).isFI() && isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs)); } void ARMBaseRegisterInfo:: emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const { MachineBasicBlock::iterator MBBI = prior(MBB.end()); assert(MBBI->getDesc().isReturn() && "Can only insert epilog into returning blocks"); DebugLoc dl = MBBI->getDebugLoc(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo(); assert(!AFI->isThumb1OnlyFunction() && "This emitEpilogue does not suppor Thumb1!"); bool isARM = !AFI->isThumbFunction(); unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); int NumBytes = (int)MFI->getStackSize(); if (!AFI->hasStackFrame()) { if (NumBytes != 0) emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes); } else { // Unwind MBBI to point to first LDR / FLDD. const unsigned *CSRegs = getCalleeSavedRegs(); if (MBBI != MBB.begin()) { do --MBBI; while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs)); if (!isCSRestore(MBBI, TII, CSRegs)) ++MBBI; } // Move SP to start of FP callee save spill area. NumBytes -= (AFI->getGPRCalleeSavedArea1Size() + AFI->getGPRCalleeSavedArea2Size() + AFI->getDPRCalleeSavedAreaSize()); // Darwin ABI requires FP to point to the stack slot that contains the // previous FP. if ((STI.isTargetDarwin() && NumBytes) || hasFP(MF)) { NumBytes = AFI->getFramePtrSpillOffset() - NumBytes; // Reset SP based on frame pointer only if the stack frame extends beyond // frame pointer stack slot or target is ELF and the function has FP. if (AFI->getGPRCalleeSavedArea2Size() || AFI->getDPRCalleeSavedAreaSize() || AFI->getDPRCalleeSavedAreaOffset()|| hasFP(MF)) { if (NumBytes) { unsigned SUBriOpc = isARM ? ARM::SUBri : ARM::t2SUBri; BuildMI(MBB, MBBI, dl, TII.get(SUBriOpc), ARM::SP) .addReg(FramePtr) .addImm(NumBytes) .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0); } else { // Thumb2 or ARM. unsigned MOVrOpc = isARM ? ARM::MOVr : ARM::t2MOVr; BuildMI(MBB, MBBI, dl, TII.get(MOVrOpc), ARM::SP) .addReg(FramePtr) .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0); } } } else if (NumBytes) emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes); // Move SP to start of integer callee save spill area 2. movePastCSLoadStoreOps(MBB, MBBI, ARM::FLDD, 0, 3, STI); emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize()); // Move SP to start of integer callee save spill area 1. movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI); emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size()); // Move SP to SP upon entry to the function. movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI); emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size()); } if (VARegSaveSize) emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize); } #include "ARMGenRegisterInfo.inc"