Thumb1FrameLowering.cpp revision 16c29b5f285f375be53dabaa73e3e91107485fe4
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 3733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikovstatic void emitSPUpdate(MachineBasicBlock &MBB, 3833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock::iterator &MBBI, 3933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const TargetInstrInfo &TII, DebugLoc dl, 4033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1RegisterInfo &MRI, 4133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int NumBytes) { 4233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII, 4333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MRI, dl); 4433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 4533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 4616c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovvoid Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const { 4733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock &MBB = MF.front(); 4833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock::iterator MBBI = MBB.begin(); 4933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineFrameInfo *MFI = MF.getFrameInfo(); 5033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); 5133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1RegisterInfo *RegInfo = 5233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo()); 5333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1InstrInfo &TII = 5433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo()); 5533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 5633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); 5733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned NumBytes = MFI->getStackSize(); 5833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); 5933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc(); 6033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned FramePtr = RegInfo->getFrameRegister(MF); 6133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned BasePtr = RegInfo->getBaseRegister(); 6233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 6333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4. 6433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes = (NumBytes + 3) & ~3; 6533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MFI->setStackSize(NumBytes); 6633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 6733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Determine the sizes of each callee-save spill areas and record which frame 6833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // belongs to which callee-save spill areas. 6933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0; 7033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int FramePtrSpillFI = 0; 7133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 7233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (VARegSaveSize) 7333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -VARegSaveSize); 7433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 7533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!AFI->hasStackFrame()) { 7633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (NumBytes != 0) 7733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes); 7833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return; 7933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 8033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 8133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov for (unsigned i = 0, e = CSI.size(); i != e; ++i) { 8233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned Reg = CSI[i].getReg(); 8333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int FI = CSI[i].getFrameIdx(); 8433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov switch (Reg) { 8533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R4: 8633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R5: 8733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R6: 8833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R7: 8933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::LR: 9033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (Reg == FramePtr) 9133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov FramePtrSpillFI = FI; 9233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addGPRCalleeSavedArea1Frame(FI); 9333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov GPRCS1Size += 4; 9433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov break; 9533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R8: 9633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R9: 9733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R10: 9833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov case ARM::R11: 9933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (Reg == FramePtr) 10033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov FramePtrSpillFI = FI; 10133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (STI.isTargetDarwin()) { 10233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addGPRCalleeSavedArea2Frame(FI); 10333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov GPRCS2Size += 4; 10433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else { 10533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addGPRCalleeSavedArea1Frame(FI); 10633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov GPRCS1Size += 4; 10733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 10833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov break; 10933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov default: 11033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->addDPRCalleeSavedAreaFrame(FI); 11133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov DPRCSSize += 8; 11233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 11333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 11433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 11533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { 11633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ++MBBI; 11733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI != MBB.end()) 11833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov dl = MBBI->getDebugLoc(); 11933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 12033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 12133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Determine starting offsets of spill areas. 12233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize); 12333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; 12433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; 12533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes); 12633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset); 12733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset); 12833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset); 12933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes = DPRCSOffset; 130ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng 131ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng // Adjust FP so it point to the stack slot that contains the previous FP. 132ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (hasFP(MF)) { 133ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr) 134ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng .addFrameIndex(FramePtrSpillFI).addImm(0); 135ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (NumBytes > 7) 136ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng // If offset is > 7 then sp cannot be adjusted in a single instruction, 137ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng // try restoring from fp instead. 138ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng AFI->setShouldRestoreSPFromFP(true); 139ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng } 140ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng 141ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (NumBytes) 14233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Insert it after all the callee-save spills. 14333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes); 14433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 145d0c38176690e9602a93a20a43f1bd084564a8116Anton Korobeynikov if (STI.isTargetELF() && hasFP(MF)) 14633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - 14733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->getFramePtrSpillOffset()); 14833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 14933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); 15033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); 15133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->setDPRCalleeSavedAreaSize(DPRCSSize); 15233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 15333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // If we need a base pointer, set it up here. It's whatever the value 15433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // of the stack pointer is at this point. Any variable size objects 15533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // will be allocated after this, so we can still use the base pointer 15633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // to reference locals. 15733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (RegInfo->hasBasePointer(MF)) 15833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), BasePtr).addReg(ARM::SP); 15933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 16033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 16133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikovstatic bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) { 16233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov for (unsigned i = 0; CSRegs[i]; ++i) 16333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (Reg == CSRegs[i]) 16433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return true; 16533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 16633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 16733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 16833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikovstatic bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) { 16933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MI->getOpcode() == ARM::tRestore && 17033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MI->getOperand(1).isFI() && 17133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs)) 17233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return true; 17333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov else if (MI->getOpcode() == ARM::tPOP) { 17433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // The first two operands are predicates. The last two are 17533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // imp-def and imp-use of SP. Check everything in between. 17633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov for (int i = 2, e = MI->getNumOperands() - 2; i != e; ++i) 17733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!isCalleeSavedRegister(MI->getOperand(i).getReg(), CSRegs)) 17833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 17933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return true; 18033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 18133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov return false; 18233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 18333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 18416c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovvoid Thumb1FrameLowering::emitEpilogue(MachineFunction &MF, 18533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock &MBB) const { 18633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock::iterator MBBI = prior(MBB.end()); 18733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov assert((MBBI->getOpcode() == ARM::tBX_RET || 18833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MBBI->getOpcode() == ARM::tPOP_RET) && 18933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov "Can only insert epilog into returning blocks"); 19033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov DebugLoc dl = MBBI->getDebugLoc(); 19133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineFrameInfo *MFI = MF.getFrameInfo(); 19233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); 19333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1RegisterInfo *RegInfo = 19433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo()); 19533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const Thumb1InstrInfo &TII = 19633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo()); 19733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 19833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); 19933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov int NumBytes = (int)MFI->getStackSize(); 20033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(); 20133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov unsigned FramePtr = RegInfo->getFrameRegister(MF); 20233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 20333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!AFI->hasStackFrame()) { 20433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (NumBytes != 0) 20533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes); 20633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else { 20733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Unwind MBBI to point to first LDR / VLDRD. 20833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI != MBB.begin()) { 20933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov do 21033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov --MBBI; 21133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs)); 21233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (!isCSRestore(MBBI, CSRegs)) 21333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ++MBBI; 21433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 21533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 21633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Move SP to start of FP callee save spill area. 21733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes -= (AFI->getGPRCalleeSavedArea1Size() + 21833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->getGPRCalleeSavedArea2Size() + 21933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AFI->getDPRCalleeSavedAreaSize()); 22033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 22133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (AFI->shouldRestoreSPFromFP()) { 22233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov NumBytes = AFI->getFramePtrSpillOffset() - NumBytes; 22333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Reset SP based on frame pointer only if the stack frame extends beyond 22433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // frame pointer stack slot or target is ELF and the function has FP. 225ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng if (NumBytes) { 226ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) && 227ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng "No scratch register to restore SP from FP!"); 228ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng emitThumbRegPlusImmediate(MBB, MBBI, ARM::R4, FramePtr, -NumBytes, 22933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov TII, *RegInfo, dl); 230ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP) 231ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng .addReg(ARM::R4); 232ab5c703fdb0b07c6d89271519fd1cca7105b3eaeEvan Cheng } else 23333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP) 23433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov .addReg(FramePtr); 23533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else { 23633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (MBBI->getOpcode() == ARM::tBX_RET && 23733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov &MBB.front() != MBBI && 23833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov prior(MBBI)->getOpcode() == ARM::tPOP) { 23933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MachineBasicBlock::iterator PMBBI = prior(MBBI); 24033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, PMBBI, TII, dl, *RegInfo, NumBytes); 24133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } else 24233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes); 24333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 24433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 24533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 24633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov if (VARegSaveSize) { 24733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Unlike T2 and ARM mode, the T1 pop instruction cannot restore 24833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // to LR, and we can't pop the value directly to the PC since 24933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // we need to update the SP after popping the value. Therefore, we 25033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // pop the old LR into R3 as a temporary. 25133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 25233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Move back past the callee-saved register restoration 25333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov while (MBBI != MBB.end() && isCSRestore(MBBI, CSRegs)) 25433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov ++MBBI; 25533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // Epilogue for vararg functions: pop LR to R3 and branch off it. 25633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP))) 25733464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov .addReg(ARM::R3, RegState::Define); 25833464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 25933464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, VARegSaveSize); 26033464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov 26133464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg)) 26233464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov .addReg(ARM::R3, RegState::Kill); 26333464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov // erase the old tBX_RET instruction 26433464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov MBB.erase(MBBI); 26533464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov } 26633464912237efaa0ed7060829e66b59055bdd48bAnton Korobeynikov} 267cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 26816c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovbool Thumb1FrameLowering:: 269cd775ceff0b25a0b026f643a7990c2924bd310a3Anton KorobeynikovspillCalleeSavedRegisters(MachineBasicBlock &MBB, 270cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineBasicBlock::iterator MI, 271cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const std::vector<CalleeSavedInfo> &CSI, 272cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetRegisterInfo *TRI) const { 273cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (CSI.empty()) 274cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return false; 275cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 276cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov DebugLoc DL; 277cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineFunction &MF = *MBB.getParent(); 278cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); 279cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 280cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (MI != MBB.end()) DL = MI->getDebugLoc(); 281cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 282cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineInstrBuilder MIB = BuildMI(MBB, MI, DL, TII.get(ARM::tPUSH)); 283cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov AddDefaultPred(MIB); 284cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov for (unsigned i = CSI.size(); i != 0; --i) { 285cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov unsigned Reg = CSI[i-1].getReg(); 286cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov bool isKill = true; 287cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 288cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // Add the callee-saved register as live-in unless it's LR and 289cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // @llvm.returnaddress is called. If LR is returned for @llvm.returnaddress 290cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // then it's already added to the function and entry block live-in sets. 291cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (Reg == ARM::LR) { 292cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineFunction &MF = *MBB.getParent(); 293cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (MF.getFrameInfo()->isReturnAddressTaken() && 294cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MF.getRegInfo().isLiveIn(Reg)) 295cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov isKill = false; 296cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 297cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 298cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (isKill) 299cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MBB.addLiveIn(Reg); 300cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 301cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MIB.addReg(Reg, getKillRegState(isKill)); 302cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 303cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return true; 304cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov} 305cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 30616c29b5f285f375be53dabaa73e3e91107485fe4Anton Korobeynikovbool Thumb1FrameLowering:: 307cd775ceff0b25a0b026f643a7990c2924bd310a3Anton KorobeynikovrestoreCalleeSavedRegisters(MachineBasicBlock &MBB, 308cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineBasicBlock::iterator MI, 309cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const std::vector<CalleeSavedInfo> &CSI, 310cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetRegisterInfo *TRI) const { 311cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (CSI.empty()) 312cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return false; 313cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 314cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineFunction &MF = *MBB.getParent(); 315cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); 316cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); 317cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 318cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov bool isVarArg = AFI->getVarArgsRegSaveSize() > 0; 319cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov DebugLoc DL = MI->getDebugLoc(); 320cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MachineInstrBuilder MIB = BuildMI(MF, DL, TII.get(ARM::tPOP)); 321cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov AddDefaultPred(MIB); 322cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 323cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov bool NumRegs = false; 324cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov for (unsigned i = CSI.size(); i != 0; --i) { 325cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov unsigned Reg = CSI[i-1].getReg(); 326cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (Reg == ARM::LR) { 327cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // Special epilogue for vararg functions. See emitEpilogue 328cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (isVarArg) 329cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov continue; 330cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov Reg = ARM::PC; 331cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov (*MIB).setDesc(TII.get(ARM::tPOP_RET)); 332cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MI = MBB.erase(MI); 333cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 334cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MIB.addReg(Reg, getDefRegState(true)); 335cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov NumRegs = true; 336cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov } 337cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 338cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov // It's illegal to emit pop instruction without operands. 339cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov if (NumRegs) 340cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MBB.insert(MI, &*MIB); 341cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov else 342cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov MF.DeleteMachineInstr(MIB); 343cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov 344cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov return true; 345cd775ceff0b25a0b026f643a7990c2924bd310a3Anton Korobeynikov} 346