Thumb1FrameLowering.cpp revision 63b46faeb8acae9b7e5f865b7417dc00b9b9dad3
116c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov//======- Thumb1FrameLowering.cpp - Thumb1 Frame Information ---*- C++ -*-====// 233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// 333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// The LLVM Compiler Infrastructure 433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// 533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// This file is distributed under the University of Illinois Open Source 633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// License. See LICENSE.TXT for details. 733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// 833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov//===----------------------------------------------------------------------===// 933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// 1016c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov// This file contains the Thumb1 implementation of TargetFrameLowering class. 1133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov// 1233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov//===----------------------------------------------------------------------===// 1333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 1416c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikov#include "Thumb1FrameLowering.h" 1533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov#include "ARMBaseInstrInfo.h" 1633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov#include "ARMMachineFunctionInfo.h" 1733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov#include "llvm/CodeGen/MachineFrameInfo.h" 1833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov#include "llvm/CodeGen/MachineFunction.h" 1933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov#include "llvm/CodeGen/MachineInstrBuilder.h" 20ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng#include "llvm/CodeGen/MachineRegisterInfo.h" 2133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 2233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikovusing namespace llvm; 2333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 2416c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovbool Thumb1FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const { 25d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov const MachineFrameInfo *FFI = MF.getFrameInfo(); 26d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov unsigned CFSize = FFI->getMaxCallFrameSize(); 27d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov // It's not always a good idea to include the call frame as part of the 28d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov // stack frame. ARM (especially Thumb) has small immediate offset to 29d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov // address the stack frame. So a large call frame can cause poor codegen 30d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov // and may even makes it impossible to scavenge a register. 31d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4 32d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov return false; 33d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov 34d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov return !MF.getFrameInfo()->hasVarSizedObjects(); 35d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov} 36d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov 373daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikovstatic void 383daccd82d3151fa3629de430b55698a81084fc9eAnton KorobeynikovemitSPUpdate(MachineBasicBlock &MBB, 393daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov MachineBasicBlock::iterator &MBBI, 403daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov const TargetInstrInfo &TII, DebugLoc dl, 413daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov const Thumb1RegisterInfo &MRI, 423daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov int NumBytes, unsigned MIFlags = MachineInstr::NoFlags) { 4357caad7a33ff145b71545f10dcfbbf2fd0f595d3Anton Korobeynikov emitThumbRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes, TII, 443daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov MRI, MIFlags); 4533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 4633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 4716c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovvoid Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const { 4833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock &MBB = MF.front(); 4933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock::iterator MBBI = MBB.begin(); 5033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineFrameInfo *MFI = MF.getFrameInfo(); 5133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); 5233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1RegisterInfo *RegInfo = 5333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo()); 5433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1InstrInfo &TII = 5533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo()); 5633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 5733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); 5833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned NumBytes = MFI->getStackSize(); 5933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); 6033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc(); 6133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned FramePtr = RegInfo->getFrameRegister(MF); 6233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned BasePtr = RegInfo->getBaseRegister(); 6333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 6433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4. 6533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes = (NumBytes + 3) & ~3; 6633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MFI->setStackSize(NumBytes); 6733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 6833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Determine the sizes of each callee-save spill areas and record which frame 6933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // belongs to which callee-save spill areas. 7033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0; 7133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int FramePtrSpillFI = 0; 7233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 7333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (VARegSaveSize) 743daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -VARegSaveSize, 753daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov MachineInstr::FrameSetup); 7633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 7733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!AFI->hasStackFrame()) { 7833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (NumBytes != 0) 793daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes, 803daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov MachineInstr::FrameSetup); 8133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return; 8233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 8333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 8433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov for (unsigned i = 0, e = CSI.size(); i != e; ++i) { 8533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned Reg = CSI[i].getReg(); 8633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int FI = CSI[i].getFrameIdx(); 8733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov switch (Reg) { 8833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R4: 8933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R5: 9033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R6: 9133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R7: 9233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::LR: 9333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (Reg == FramePtr) 9433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov FramePtrSpillFI = FI; 9533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addGPRCalleeSavedArea1Frame(FI); 9633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov GPRCS1Size += 4; 9733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov break; 9833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R8: 9933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R9: 10033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R10: 10133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R11: 10233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (Reg == FramePtr) 10333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov FramePtrSpillFI = FI; 10433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (STI.isTargetDarwin()) { 10533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addGPRCalleeSavedArea2Frame(FI); 10633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov GPRCS2Size += 4; 10733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else { 10833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addGPRCalleeSavedArea1Frame(FI); 10933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov GPRCS1Size += 4; 11033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 11133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov break; 11233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov default: 11333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addDPRCalleeSavedAreaFrame(FI); 11433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov DPRCSSize += 8; 11533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 11633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 11733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 11833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { 11933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ++MBBI; 12033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI != MBB.end()) 12133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov dl = MBBI->getDebugLoc(); 12233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 12333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 12433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Determine starting offsets of spill areas. 12533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize); 12633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; 12733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; 12833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes); 12933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset); 13033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset); 13133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset); 13233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes = DPRCSOffset; 133ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng 134ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng // Adjust FP so it point to the stack slot that contains the previous FP. 135ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (hasFP(MF)) { 136ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr) 1373daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov .addFrameIndex(FramePtrSpillFI).addImm(0) 1383daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov .setMIFlags(MachineInstr::FrameSetup); 1397980f61f5ff408b947474cd1c3715896d28ea578Jim Grosbach if (NumBytes > 508) 1407980f61f5ff408b947474cd1c3715896d28ea578Jim Grosbach // If offset is > 508 then sp cannot be adjusted in a single instruction, 141ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng // try restoring from fp instead. 142ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng AFI->setShouldRestoreSPFromFP(true); 143ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng } 144ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng 145ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (NumBytes) 14633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Insert it after all the callee-save spills. 1473daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes, 1483daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov MachineInstr::FrameSetup); 14933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 150d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov if (STI.isTargetELF() && hasFP(MF)) 15133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - 15233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->getFramePtrSpillOffset()); 15333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 15433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); 15533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); 15633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setDPRCalleeSavedAreaSize(DPRCSSize); 15733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 15833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // If we need a base pointer, set it up here. It's whatever the value 15933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // of the stack pointer is at this point. Any variable size objects 16033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // will be allocated after this, so we can still use the base pointer 16133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // to reference locals. 16233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (RegInfo->hasBasePointer(MF)) 16363b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), BasePtr) 16463b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach .addReg(ARM::SP)); 1653daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov 16694bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher // If the frame has variable sized objects then the epilogue must restore 16794bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher // the sp from fp. We can assume there's an FP here since hasFP already 16894bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher // checks for hasVarSizedObjects. 16994bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher if (MFI->hasVarSizedObjects()) 17094bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher AFI->setShouldRestoreSPFromFP(true); 17133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 17233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 17333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikovstatic bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) { 17433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov for (unsigned i = 0; CSRegs[i]; ++i) 17533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (Reg == CSRegs[i]) 17633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return true; 17733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 17833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 17933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 18033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikovstatic bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) { 18174472b4bf963c424da04f42dffdb94c85ef964bcJim Grosbach if (MI->getOpcode() == ARM::tLDRspi && 18233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MI->getOperand(1).isFI() && 18333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs)) 18433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return true; 18533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov else if (MI->getOpcode() == ARM::tPOP) { 18633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // The first two operands are predicates. The last two are 18733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // imp-def and imp-use of SP. Check everything in between. 18833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov for (int i = 2, e = MI->getNumOperands() - 2; i != e; ++i) 18933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!isCalleeSavedRegister(MI->getOperand(i).getReg(), CSRegs)) 19033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 19133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return true; 19233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 19333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 19433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 19533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 19616c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovvoid Thumb1FrameLowering::emitEpilogue(MachineFunction &MF, 19733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock &MBB) const { 1984f28c1c71450c711e96aa283de53739d8b4504cdJakob Stoklund Olesen MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr(); 19933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov assert((MBBI->getOpcode() == ARM::tBX_RET || 20033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MBBI->getOpcode() == ARM::tPOP_RET) && 20133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov "Can only insert epilog into returning blocks"); 20233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov DebugLoc dl = MBBI->getDebugLoc(); 20333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineFrameInfo *MFI = MF.getFrameInfo(); 20433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); 20533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1RegisterInfo *RegInfo = 20633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo()); 20733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1InstrInfo &TII = 20833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo()); 20933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 21033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); 21133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int NumBytes = (int)MFI->getStackSize(); 21233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(); 21333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned FramePtr = RegInfo->getFrameRegister(MF); 21433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 21533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!AFI->hasStackFrame()) { 21633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (NumBytes != 0) 21733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes); 21833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else { 21933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Unwind MBBI to point to first LDR / VLDRD. 22033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI != MBB.begin()) { 22133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov do 22233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov --MBBI; 22333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs)); 22433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!isCSRestore(MBBI, CSRegs)) 22533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ++MBBI; 22633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 22733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 22833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Move SP to start of FP callee save spill area. 22933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes -= (AFI->getGPRCalleeSavedArea1Size() + 23033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->getGPRCalleeSavedArea2Size() + 23133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->getDPRCalleeSavedAreaSize()); 23233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 23333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (AFI->shouldRestoreSPFromFP()) { 23433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes = AFI->getFramePtrSpillOffset() - NumBytes; 23533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Reset SP based on frame pointer only if the stack frame extends beyond 23694bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher // frame pointer stack slot, the target is ELF and the function has FP, or 23794bb7b561c16878ae442adeb13dd42140b55d027Eric Christopher // the target uses var sized objects. 238ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (NumBytes) { 239ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) && 240ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng "No scratch register to restore SP from FP!"); 24157caad7a33ff145b71545f10dcfbbf2fd0f595d3Anton Korobeynikov emitThumbRegPlusImmediate(MBB, MBBI, dl, ARM::R4, FramePtr, -NumBytes, 24257caad7a33ff145b71545f10dcfbbf2fd0f595d3Anton Korobeynikov TII, *RegInfo); 24363b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), 24463b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach ARM::SP) 24563b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach .addReg(ARM::R4)); 246ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng } else 24763b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), 24863b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach ARM::SP) 24963b46faeb8acae9b7e5f865b7417dc00b9b9dad3Jim Grosbach .addReg(FramePtr)); 25033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else { 25133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI->getOpcode() == ARM::tBX_RET && 25233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov &MBB.front() != MBBI && 25333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov prior(MBBI)->getOpcode() == ARM::tPOP) { 25433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock::iterator PMBBI = prior(MBBI); 25533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, PMBBI, TII, dl, *RegInfo, NumBytes); 25633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else 25733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes); 25833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 25933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 26033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 26133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (VARegSaveSize) { 26233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Unlike T2 and ARM mode, the T1 pop instruction cannot restore 26333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // to LR, and we can't pop the value directly to the PC since 26433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // we need to update the SP after popping the value. Therefore, we 26533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // pop the old LR into R3 as a temporary. 26633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 26733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Move back past the callee-saved register restoration 26833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov while (MBBI != MBB.end() && isCSRestore(MBBI, CSRegs)) 26933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ++MBBI; 27033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Epilogue for vararg functions: pop LR to R3 and branch off it. 27133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP))) 27233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov .addReg(ARM::R3, RegState::Define); 27333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 27433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, VARegSaveSize); 27533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 27633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg)) 27733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov .addReg(ARM::R3, RegState::Kill); 27833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // erase the old tBX_RET instruction 27933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MBB.erase(MBBI); 28033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 28133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 282cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 28316c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovbool Thumb1FrameLowering:: 284cd775ceff0b25a0b026f643a7990c2924bd310a3Anton KorobeynikovspillCalleeSavedRegisters(MachineBasicBlock &MBB, 285cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineBasicBlock::iterator MI, 286cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const std::vector<CalleeSavedInfo> &CSI, 287cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetRegisterInfo *TRI) const { 288cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (CSI.empty()) 289cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return false; 290cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 291cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov DebugLoc DL; 292cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineFunction &MF = *MBB.getParent(); 293cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); 294cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 295cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (MI != MBB.end()) DL = MI->getDebugLoc(); 296cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 297cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineInstrBuilder MIB = BuildMI(MBB, MI, DL, TII.get(ARM::tPUSH)); 298cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov AddDefaultPred(MIB); 299cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov for (unsigned i = CSI.size(); i != 0; --i) { 300cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov unsigned Reg = CSI[i-1].getReg(); 301cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov bool isKill = true; 302cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 303cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // Add the callee-saved register as live-in unless it's LR and 304cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // @llvm.returnaddress is called. If LR is returned for @llvm.returnaddress 305cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // then it's already added to the function and entry block live-in sets. 306cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (Reg == ARM::LR) { 307cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineFunction &MF = *MBB.getParent(); 308cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (MF.getFrameInfo()->isReturnAddressTaken() && 309cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MF.getRegInfo().isLiveIn(Reg)) 310cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov isKill = false; 311cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 312cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 313cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (isKill) 314cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MBB.addLiveIn(Reg); 315cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 316cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MIB.addReg(Reg, getKillRegState(isKill)); 317cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 3183daccd82d3151fa3629de430b55698a81084fc9eAnton Korobeynikov MIB.setMIFlags(MachineInstr::FrameSetup); 319cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return true; 320cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov} 321cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 32216c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovbool Thumb1FrameLowering:: 323cd775ceff0b25a0b026f643a7990c2924bd310a3Anton KorobeynikovrestoreCalleeSavedRegisters(MachineBasicBlock &MBB, 324cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineBasicBlock::iterator MI, 325cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const std::vector<CalleeSavedInfo> &CSI, 326cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetRegisterInfo *TRI) const { 327cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (CSI.empty()) 328cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return false; 329cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 330cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineFunction &MF = *MBB.getParent(); 331cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); 332cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); 333cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 334cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov bool isVarArg = AFI->getVarArgsRegSaveSize() > 0; 335cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov DebugLoc DL = MI->getDebugLoc(); 336cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineInstrBuilder MIB = BuildMI(MF, DL, TII.get(ARM::tPOP)); 337cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov AddDefaultPred(MIB); 338cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 339cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov bool NumRegs = false; 340cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov for (unsigned i = CSI.size(); i != 0; --i) { 341cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov unsigned Reg = CSI[i-1].getReg(); 342cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (Reg == ARM::LR) { 343cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // Special epilogue for vararg functions. See emitEpilogue 344cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (isVarArg) 345cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov continue; 346cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov Reg = ARM::PC; 347cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov (*MIB).setDesc(TII.get(ARM::tPOP_RET)); 348cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MI = MBB.erase(MI); 349cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 350cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MIB.addReg(Reg, getDefRegState(true)); 351cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov NumRegs = true; 352cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 353cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 354cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // It's illegal to emit pop instruction without operands. 355cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (NumRegs) 356cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MBB.insert(MI, &*MIB); 357cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov else 358cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MF.DeleteMachineInstr(MIB); 359cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 360cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return true; 361cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov} 362