void Thumb1FrameLowering::emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const { MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); MachineModuleInfo &MMI = MF.getMMI(); const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo(); const ThumbRegisterInfo *RegInfo = static_cast<const ThumbRegisterInfo *>(STI.getRegisterInfo()); const Thumb1InstrInfo &TII = *static_cast<const Thumb1InstrInfo *>(STI.getInstrInfo()); unsigned ArgRegsSaveSize = AFI->getArgRegsSaveSize(); unsigned NumBytes = MFI->getStackSize(); assert(NumBytes >= ArgRegsSaveSize && "ArgRegsSaveSize is included in NumBytes"); const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); // Debug location must be unknown since the first debug location is used // to determine the end of the prologue. DebugLoc dl; unsigned FramePtr = RegInfo->getFrameRegister(MF); unsigned BasePtr = RegInfo->getBaseRegister(); int CFAOffset = 0; // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4. NumBytes = (NumBytes + 3) & ~3; MFI->setStackSize(NumBytes); // 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 (ArgRegsSaveSize) { emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -ArgRegsSaveSize, MachineInstr::FrameSetup); CFAOffset -= ArgRegsSaveSize; unsigned CFIIndex = MMI.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } if (!AFI->hasStackFrame()) { if (NumBytes - ArgRegsSaveSize != 0) { emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -(NumBytes - ArgRegsSaveSize), MachineInstr::FrameSetup); CFAOffset -= NumBytes - ArgRegsSaveSize; unsigned CFIIndex = MMI.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } 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::R8: case ARM::R9: case ARM::R10: case ARM::R11: if (STI.isTargetMachO()) { GPRCS2Size += 4; break; } // fallthrough case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: if (Reg == FramePtr) FramePtrSpillFI = FI; GPRCS1Size += 4; break; default: DPRCSSize += 8; } } if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { ++MBBI; } // Determine starting offsets of spill areas. unsigned DPRCSOffset = NumBytes - ArgRegsSaveSize - (GPRCS1Size + GPRCS2Size + DPRCSSize); unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; bool HasFP = hasFP(MF); if (HasFP) AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes); AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset); AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset); AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset); NumBytes = DPRCSOffset; int FramePtrOffsetInBlock = 0; unsigned adjustedGPRCS1Size = GPRCS1Size; if (tryFoldSPUpdateIntoPushPop(STI, MF, std::prev(MBBI), NumBytes)) { FramePtrOffsetInBlock = NumBytes; adjustedGPRCS1Size += NumBytes; NumBytes = 0; } if (adjustedGPRCS1Size) { CFAOffset -= adjustedGPRCS1Size; unsigned CFIIndex = MMI.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(), E = CSI.end(); I != E; ++I) { unsigned Reg = I->getReg(); int FI = I->getFrameIdx(); switch (Reg) { case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: case ARM::R12: if (STI.isTargetMachO()) break; // fallthough case ARM::R0: case ARM::R1: case ARM::R2: case ARM::R3: case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( nullptr, MRI->getDwarfRegNum(Reg, true), MFI->getObjectOffset(FI))); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); break; } } // Adjust FP so it point to the stack slot that contains the previous FP. if (HasFP) { FramePtrOffsetInBlock += MFI->getObjectOffset(FramePtrSpillFI) + GPRCS1Size + ArgRegsSaveSize; AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr) .addReg(ARM::SP).addImm(FramePtrOffsetInBlock / 4) .setMIFlags(MachineInstr::FrameSetup)); if(FramePtrOffsetInBlock) { CFAOffset += FramePtrOffsetInBlock; unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfa( nullptr, MRI->getDwarfRegNum(FramePtr, true), CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } else { unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister( nullptr, MRI->getDwarfRegNum(FramePtr, true))); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } if (NumBytes > 508) // If offset is > 508 then sp cannot be adjusted in a single instruction, // try restoring from fp instead. AFI->setShouldRestoreSPFromFP(true); } if (NumBytes) { // Insert it after all the callee-save spills. emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes, MachineInstr::FrameSetup); if (!HasFP) { CFAOffset -= NumBytes; unsigned CFIIndex = MMI.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } } if (STI.isTargetELF() && HasFP) MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - AFI->getFramePtrSpillOffset()); AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); // Thumb1 does not currently support dynamic stack realignment. Report a // fatal error rather then silently generate bad code. if (RegInfo->needsStackRealignment(MF)) report_fatal_error("Dynamic stack realignment not supported for thumb1."); // If we need a base pointer, set it up here. It's whatever the value // of the stack pointer is at this point. Any variable size objects // will be allocated after this, so we can still use the base pointer // to reference locals. if (RegInfo->hasBasePointer(MF)) AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), BasePtr) .addReg(ARM::SP)); // If the frame has variable sized objects then the epilogue must restore // the sp from fp. We can assume there's an FP here since hasFP already // checks for hasVarSizedObjects. if (MFI->hasVarSizedObjects()) AFI->setShouldRestoreSPFromFP(true); }
void Thumb1FrameLowering::emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const { MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo &MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); MachineModuleInfo &MMI = MF.getMMI(); const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo(); const ThumbRegisterInfo *RegInfo = static_cast<const ThumbRegisterInfo *>(STI.getRegisterInfo()); const Thumb1InstrInfo &TII = *static_cast<const Thumb1InstrInfo *>(STI.getInstrInfo()); unsigned ArgRegsSaveSize = AFI->getArgRegsSaveSize(); unsigned NumBytes = MFI.getStackSize(); assert(NumBytes >= ArgRegsSaveSize && "ArgRegsSaveSize is included in NumBytes"); const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo(); // Debug location must be unknown since the first debug location is used // to determine the end of the prologue. DebugLoc dl; unsigned FramePtr = RegInfo->getFrameRegister(MF); unsigned BasePtr = RegInfo->getBaseRegister(); int CFAOffset = 0; // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4. NumBytes = (NumBytes + 3) & ~3; MFI.setStackSize(NumBytes); // 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 (ArgRegsSaveSize) { emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -ArgRegsSaveSize, MachineInstr::FrameSetup); CFAOffset -= ArgRegsSaveSize; unsigned CFIIndex = MF.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } if (!AFI->hasStackFrame()) { if (NumBytes - ArgRegsSaveSize != 0) { emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -(NumBytes - ArgRegsSaveSize), MachineInstr::FrameSetup); CFAOffset -= NumBytes - ArgRegsSaveSize; unsigned CFIIndex = MF.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } 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::R8: case ARM::R9: case ARM::R10: case ARM::R11: if (STI.splitFramePushPop(MF)) { GPRCS2Size += 4; break; } LLVM_FALLTHROUGH; case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: if (Reg == FramePtr) FramePtrSpillFI = FI; GPRCS1Size += 4; break; default: DPRCSSize += 8; } } if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { ++MBBI; } // Determine starting offsets of spill areas. unsigned DPRCSOffset = NumBytes - ArgRegsSaveSize - (GPRCS1Size + GPRCS2Size + DPRCSSize); unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; bool HasFP = hasFP(MF); if (HasFP) AFI->setFramePtrSpillOffset(MFI.getObjectOffset(FramePtrSpillFI) + NumBytes); AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset); AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset); AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset); NumBytes = DPRCSOffset; int FramePtrOffsetInBlock = 0; unsigned adjustedGPRCS1Size = GPRCS1Size; if (GPRCS1Size > 0 && GPRCS2Size == 0 && tryFoldSPUpdateIntoPushPop(STI, MF, &*std::prev(MBBI), NumBytes)) { FramePtrOffsetInBlock = NumBytes; adjustedGPRCS1Size += NumBytes; NumBytes = 0; } if (adjustedGPRCS1Size) { CFAOffset -= adjustedGPRCS1Size; unsigned CFIIndex = MF.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(), E = CSI.end(); I != E; ++I) { unsigned Reg = I->getReg(); int FI = I->getFrameIdx(); switch (Reg) { case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: case ARM::R12: if (STI.splitFramePushPop(MF)) break; LLVM_FALLTHROUGH; case ARM::R0: case ARM::R1: case ARM::R2: case ARM::R3: case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7: case ARM::LR: unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createOffset( nullptr, MRI->getDwarfRegNum(Reg, true), MFI.getObjectOffset(FI))); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); break; } } // Adjust FP so it point to the stack slot that contains the previous FP. if (HasFP) { FramePtrOffsetInBlock += MFI.getObjectOffset(FramePtrSpillFI) + GPRCS1Size + ArgRegsSaveSize; BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr) .addReg(ARM::SP) .addImm(FramePtrOffsetInBlock / 4) .setMIFlags(MachineInstr::FrameSetup) .add(predOps(ARMCC::AL)); if(FramePtrOffsetInBlock) { CFAOffset += FramePtrOffsetInBlock; unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createDefCfa( nullptr, MRI->getDwarfRegNum(FramePtr, true), CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } else { unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createDefCfaRegister( nullptr, MRI->getDwarfRegNum(FramePtr, true))); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } if (NumBytes > 508) // If offset is > 508 then sp cannot be adjusted in a single instruction, // try restoring from fp instead. AFI->setShouldRestoreSPFromFP(true); } // Skip past the spilling of r8-r11, which could consist of multiple tPUSH // and tMOVr instructions. We don't need to add any call frame information // in-between these instructions, because they do not modify the high // registers. while (true) { MachineBasicBlock::iterator OldMBBI = MBBI; // Skip a run of tMOVr instructions while (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tMOVr) MBBI++; if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { MBBI++; } else { // We have reached an instruction which is not a push, so the previous // run of tMOVr instructions (which may have been empty) was not part of // the prologue. Reset MBBI back to the last PUSH of the prologue. MBBI = OldMBBI; break; } } // Emit call frame information for the callee-saved high registers. for (auto &I : CSI) { unsigned Reg = I.getReg(); int FI = I.getFrameIdx(); switch (Reg) { case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: case ARM::R12: { unsigned CFIIndex = MF.addFrameInst(MCCFIInstruction::createOffset( nullptr, MRI->getDwarfRegNum(Reg, true), MFI.getObjectOffset(FI))); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); break; } default: break; } } if (NumBytes) { // Insert it after all the callee-save spills. emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes, MachineInstr::FrameSetup); if (!HasFP) { CFAOffset -= NumBytes; unsigned CFIIndex = MF.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex) .setMIFlags(MachineInstr::FrameSetup); } } if (STI.isTargetELF() && HasFP) MFI.setOffsetAdjustment(MFI.getOffsetAdjustment() - AFI->getFramePtrSpillOffset()); AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); if (RegInfo->needsStackRealignment(MF)) { const unsigned NrBitsToZero = countTrailingZeros(MFI.getMaxAlignment()); // Emit the following sequence, using R4 as a temporary, since we cannot use // SP as a source or destination register for the shifts: // mov r4, sp // lsrs r4, r4, #NrBitsToZero // lsls r4, r4, #NrBitsToZero // mov sp, r4 BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), ARM::R4) .addReg(ARM::SP, RegState::Kill) .add(predOps(ARMCC::AL)); BuildMI(MBB, MBBI, dl, TII.get(ARM::tLSRri), ARM::R4) .addDef(ARM::CPSR) .addReg(ARM::R4, RegState::Kill) .addImm(NrBitsToZero) .add(predOps(ARMCC::AL)); BuildMI(MBB, MBBI, dl, TII.get(ARM::tLSLri), ARM::R4) .addDef(ARM::CPSR) .addReg(ARM::R4, RegState::Kill) .addImm(NrBitsToZero) .add(predOps(ARMCC::AL)); BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), ARM::SP) .addReg(ARM::R4, RegState::Kill) .add(predOps(ARMCC::AL)); AFI->setShouldRestoreSPFromFP(true); } // If we need a base pointer, set it up here. It's whatever the value // of the stack pointer is at this point. Any variable size objects // will be allocated after this, so we can still use the base pointer // to reference locals. if (RegInfo->hasBasePointer(MF)) BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), BasePtr) .addReg(ARM::SP) .add(predOps(ARMCC::AL)); // If the frame has variable sized objects then the epilogue must restore // the sp from fp. We can assume there's an FP here since hasFP already // checks for hasVarSizedObjects. if (MFI.hasVarSizedObjects()) AFI->setShouldRestoreSPFromFP(true); // In some cases, virtual registers have been introduced, e.g. by uses of // emitThumbRegPlusImmInReg. MF.getProperties().reset(MachineFunctionProperties::Property::NoVRegs); }
void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); const ARMBaseRegisterInfo *RegInfo = static_cast<const ARMBaseRegisterInfo*>(MF.getTarget().getRegisterInfo()); const ARMBaseInstrInfo &TII = *static_cast<const ARMBaseInstrInfo*>(MF.getTarget().getInstrInfo()); assert(!AFI->isThumb1OnlyFunction() && "This emitPrologue does not support Thumb1!"); bool isARM = !AFI->isThumbFunction(); unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); unsigned NumBytes = MFI->getStackSize(); const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc(); unsigned FramePtr = RegInfo->getFrameRegister(MF); // 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; // Allocate the vararg register save area. This is not counted in NumBytes. if (VARegSaveSize) emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize, MachineInstr::FrameSetup); if (!AFI->hasStackFrame()) { if (NumBytes != 0) emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes, MachineInstr::FrameSetup); 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; } } // Move past area 1. if (GPRCS1Size > 0) MBBI++; // Set FP to point to the stack slot that contains the previous FP. // For Darwin, FP is R7, which has now been stored in spill area 1. // Otherwise, if this is not Darwin, all the callee-saved registers go // into spill area 1, including the FP in R11. In either case, it is // now safe to emit this assignment. bool HasFP = hasFP(MF); if (HasFP) { unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri; MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr) .addFrameIndex(FramePtrSpillFI).addImm(0) .setMIFlag(MachineInstr::FrameSetup); AddDefaultCC(AddDefaultPred(MIB)); } // Move past area 2. if (GPRCS2Size > 0) MBBI++; // Determine starting offsets of spill areas. unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize); unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; if (HasFP) AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes); AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset); AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset); AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset); // Move past area 3. if (DPRCSSize > 0) { MBBI++; // Since vpush register list cannot have gaps, there may be multiple vpush // instructions in the prologue. while (MBBI->getOpcode() == ARM::VSTMDDB_UPD) MBBI++; } NumBytes = DPRCSOffset; if (NumBytes) { // Adjust SP after all the callee-save spills. emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes, MachineInstr::FrameSetup); if (HasFP && isARM) // Restore from fp only in ARM mode: e.g. sub sp, r7, #24 // Note it's not safe to do this in Thumb2 mode because it would have // taken two instructions: // mov sp, r7 // sub sp, #24 // If an interrupt is taken between the two instructions, then sp is in // an inconsistent state (pointing to the middle of callee-saved area). // The interrupt handler can end up clobbering the registers. AFI->setShouldRestoreSPFromFP(true); } if (STI.isTargetELF() && hasFP(MF)) MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - AFI->getFramePtrSpillOffset()); AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); // If we need dynamic stack realignment, do it here. Be paranoid and make // sure if we also have VLAs, we have a base pointer for frame access. if (RegInfo->needsStackRealignment(MF)) { unsigned MaxAlign = MFI->getMaxAlignment(); assert (!AFI->isThumb1OnlyFunction()); if (!AFI->isThumbFunction()) { // Emit bic sp, sp, MaxAlign AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::BICri), ARM::SP) .addReg(ARM::SP, RegState::Kill) .addImm(MaxAlign-1))); } else { // We cannot use sp as source/dest register here, thus we're emitting the // following sequence: // mov r4, sp // bic r4, r4, MaxAlign // mov sp, r4 // FIXME: It will be better just to find spare register here. AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), ARM::R4) .addReg(ARM::SP, RegState::Kill)); AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::t2BICri), ARM::R4) .addReg(ARM::R4, RegState::Kill) .addImm(MaxAlign-1))); AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), ARM::SP) .addReg(ARM::R4, RegState::Kill)); } AFI->setShouldRestoreSPFromFP(true); } // If we need a base pointer, set it up here. It's whatever the value // of the stack pointer is at this point. Any variable size objects // will be allocated after this, so we can still use the base pointer // to reference locals. // FIXME: Clarify FrameSetup flags here. if (RegInfo->hasBasePointer(MF)) { if (isARM) BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), RegInfo->getBaseRegister()) .addReg(ARM::SP) .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0); else AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), RegInfo->getBaseRegister()) .addReg(ARM::SP)); } // If the frame has variable sized objects then the epilogue must restore // the sp from fp. We can assume there's an FP here since hasFP already // checks for hasVarSizedObjects. if (MFI->hasVarSizedObjects()) AFI->setShouldRestoreSPFromFP(true); }
void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); const Thumb1RegisterInfo *RegInfo = static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo()); const Thumb1InstrInfo &TII = *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo()); unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); unsigned NumBytes = MFI->getStackSize(); const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc(); unsigned FramePtr = RegInfo->getFrameRegister(MF); unsigned BasePtr = RegInfo->getBaseRegister(); // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4. NumBytes = (NumBytes + 3) & ~3; MFI->setStackSize(NumBytes); // 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(MBB, MBBI, TII, dl, *RegInfo, -VARegSaveSize, MachineInstr::FrameSetup); if (!AFI->hasStackFrame()) { if (NumBytes != 0) emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes, MachineInstr::FrameSetup); 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; } } if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { ++MBBI; if (MBBI != MBB.end()) dl = MBBI->getDebugLoc(); } // 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; // Adjust FP so it point to the stack slot that contains the previous FP. if (hasFP(MF)) { AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr) .addFrameIndex(FramePtrSpillFI).addImm(0) .setMIFlags(MachineInstr::FrameSetup)); if (NumBytes > 508) // If offset is > 508 then sp cannot be adjusted in a single instruction, // try restoring from fp instead. AFI->setShouldRestoreSPFromFP(true); } if (NumBytes) // Insert it after all the callee-save spills. emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes, MachineInstr::FrameSetup); if (STI.isTargetELF() && hasFP(MF)) MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - AFI->getFramePtrSpillOffset()); AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); // If we need a base pointer, set it up here. It's whatever the value // of the stack pointer is at this point. Any variable size objects // will be allocated after this, so we can still use the base pointer // to reference locals. if (RegInfo->hasBasePointer(MF)) AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), BasePtr) .addReg(ARM::SP)); // If the frame has variable sized objects then the epilogue must restore // the sp from fp. We can assume there's an FP here since hasFP already // checks for hasVarSizedObjects. if (MFI->hasVarSizedObjects()) AFI->setShouldRestoreSPFromFP(true); }
void Thumb1RegisterInfo::emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>(); unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize(); unsigned NumBytes = MFI->getStackSize(); const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); DebugLoc dl = (MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc::getUnknownLoc()); // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4. NumBytes = (NumBytes + 3) & ~3; MFI->setStackSize(NumBytes); // 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(MBB, MBBI, TII, dl, *this, -VARegSaveSize); if (!AFI->hasStackFrame()) { if (NumBytes != 0) emitSPUpdate(MBB, MBBI, TII, dl, *this, -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; } } if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) { ++MBBI; if (MBBI != MBB.end()) dl = MBBI->getDebugLoc(); } // Darwin ABI requires FP to point to the stack slot that contains the // previous FP. if (STI.isTargetDarwin() || hasFP(MF)) { BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr) .addFrameIndex(FramePtrSpillFI).addImm(0); } // 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. emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes); } if (STI.isTargetELF() && hasFP(MF)) { MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() - AFI->getFramePtrSpillOffset()); } AFI->setGPRCalleeSavedArea1Size(GPRCS1Size); AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); }