//===-- PPCFrameLowering.cpp - PPC Frame Information ----------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains the PPC implementation of TargetFrameLowering class. // //===----------------------------------------------------------------------===// #include "PPCFrameLowering.h" #include "PPCInstrBuilder.h" #include "PPCInstrInfo.h" #include "PPCMachineFunctionInfo.h" #include "PPCSubtarget.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/RegisterScavenging.h" #include "llvm/IR/Function.h" #include "llvm/Target/TargetOptions.h" using namespace llvm; /// VRRegNo - Map from a numbered VR register to its enum value. /// static const uint16_t VRRegNo[] = { PPC::V0 , PPC::V1 , PPC::V2 , PPC::V3 , PPC::V4 , PPC::V5 , PPC::V6 , PPC::V7 , PPC::V8 , PPC::V9 , PPC::V10, PPC::V11, PPC::V12, PPC::V13, PPC::V14, PPC::V15, PPC::V16, PPC::V17, PPC::V18, PPC::V19, PPC::V20, PPC::V21, PPC::V22, PPC::V23, PPC::V24, PPC::V25, PPC::V26, PPC::V27, PPC::V28, PPC::V29, PPC::V30, PPC::V31 }; PPCFrameLowering::PPCFrameLowering(const PPCSubtarget &STI) : TargetFrameLowering(TargetFrameLowering::StackGrowsDown, (STI.hasQPX() || STI.isBGQ()) ? 32 : 16, 0), Subtarget(STI) {} // With the SVR4 ABI, callee-saved registers have fixed offsets on the stack. const PPCFrameLowering::SpillSlot *PPCFrameLowering::getCalleeSavedSpillSlots( unsigned &NumEntries) const { if (Subtarget.isDarwinABI()) { NumEntries = 1; if (Subtarget.isPPC64()) { static const SpillSlot darwin64Offsets = {PPC::X31, -8}; return &darwin64Offsets; } else { static const SpillSlot darwinOffsets = {PPC::R31, -4}; return &darwinOffsets; } } // Early exit if not using the SVR4 ABI. if (!Subtarget.isSVR4ABI()) { NumEntries = 0; return nullptr; } // Note that the offsets here overlap, but this is fixed up in // processFunctionBeforeFrameFinalized. static const SpillSlot Offsets[] = { // Floating-point register save area offsets. {PPC::F31, -8}, {PPC::F30, -16}, {PPC::F29, -24}, {PPC::F28, -32}, {PPC::F27, -40}, {PPC::F26, -48}, {PPC::F25, -56}, {PPC::F24, -64}, {PPC::F23, -72}, {PPC::F22, -80}, {PPC::F21, -88}, {PPC::F20, -96}, {PPC::F19, -104}, {PPC::F18, -112}, {PPC::F17, -120}, {PPC::F16, -128}, {PPC::F15, -136}, {PPC::F14, -144}, // General register save area offsets. {PPC::R31, -4}, {PPC::R30, -8}, {PPC::R29, -12}, {PPC::R28, -16}, {PPC::R27, -20}, {PPC::R26, -24}, {PPC::R25, -28}, {PPC::R24, -32}, {PPC::R23, -36}, {PPC::R22, -40}, {PPC::R21, -44}, {PPC::R20, -48}, {PPC::R19, -52}, {PPC::R18, -56}, {PPC::R17, -60}, {PPC::R16, -64}, {PPC::R15, -68}, {PPC::R14, -72}, // CR save area offset. We map each of the nonvolatile CR fields // to the slot for CR2, which is the first of the nonvolatile CR // fields to be assigned, so that we only allocate one save slot. // See PPCRegisterInfo::hasReservedSpillSlot() for more information. {PPC::CR2, -4}, // VRSAVE save area offset. {PPC::VRSAVE, -4}, // Vector register save area {PPC::V31, -16}, {PPC::V30, -32}, {PPC::V29, -48}, {PPC::V28, -64}, {PPC::V27, -80}, {PPC::V26, -96}, {PPC::V25, -112}, {PPC::V24, -128}, {PPC::V23, -144}, {PPC::V22, -160}, {PPC::V21, -176}, {PPC::V20, -192}}; static const SpillSlot Offsets64[] = { // Floating-point register save area offsets. {PPC::F31, -8}, {PPC::F30, -16}, {PPC::F29, -24}, {PPC::F28, -32}, {PPC::F27, -40}, {PPC::F26, -48}, {PPC::F25, -56}, {PPC::F24, -64}, {PPC::F23, -72}, {PPC::F22, -80}, {PPC::F21, -88}, {PPC::F20, -96}, {PPC::F19, -104}, {PPC::F18, -112}, {PPC::F17, -120}, {PPC::F16, -128}, {PPC::F15, -136}, {PPC::F14, -144}, // General register save area offsets. {PPC::X31, -8}, {PPC::X30, -16}, {PPC::X29, -24}, {PPC::X28, -32}, {PPC::X27, -40}, {PPC::X26, -48}, {PPC::X25, -56}, {PPC::X24, -64}, {PPC::X23, -72}, {PPC::X22, -80}, {PPC::X21, -88}, {PPC::X20, -96}, {PPC::X19, -104}, {PPC::X18, -112}, {PPC::X17, -120}, {PPC::X16, -128}, {PPC::X15, -136}, {PPC::X14, -144}, // VRSAVE save area offset. {PPC::VRSAVE, -4}, // Vector register save area {PPC::V31, -16}, {PPC::V30, -32}, {PPC::V29, -48}, {PPC::V28, -64}, {PPC::V27, -80}, {PPC::V26, -96}, {PPC::V25, -112}, {PPC::V24, -128}, {PPC::V23, -144}, {PPC::V22, -160}, {PPC::V21, -176}, {PPC::V20, -192}}; if (Subtarget.isPPC64()) { NumEntries = array_lengthof(Offsets64); return Offsets64; } else { NumEntries = array_lengthof(Offsets); return Offsets; } } /// RemoveVRSaveCode - We have found that this function does not need any code /// to manipulate the VRSAVE register, even though it uses vector registers. /// This can happen when the only registers used are known to be live in or out /// of the function. Remove all of the VRSAVE related code from the function. /// FIXME: The removal of the code results in a compile failure at -O0 when the /// function contains a function call, as the GPR containing original VRSAVE /// contents is spilled and reloaded around the call. Without the prolog code, /// the spill instruction refers to an undefined register. This code needs /// to account for all uses of that GPR. static void RemoveVRSaveCode(MachineInstr *MI) { MachineBasicBlock *Entry = MI->getParent(); MachineFunction *MF = Entry->getParent(); // We know that the MTVRSAVE instruction immediately follows MI. Remove it. MachineBasicBlock::iterator MBBI = MI; ++MBBI; assert(MBBI != Entry->end() && MBBI->getOpcode() == PPC::MTVRSAVE); MBBI->eraseFromParent(); bool RemovedAllMTVRSAVEs = true; // See if we can find and remove the MTVRSAVE instruction from all of the // epilog blocks. for (MachineFunction::iterator I = MF->begin(), E = MF->end(); I != E; ++I) { // If last instruction is a return instruction, add an epilogue if (!I->empty() && I->back().isReturn()) { bool FoundIt = false; for (MBBI = I->end(); MBBI != I->begin(); ) { --MBBI; if (MBBI->getOpcode() == PPC::MTVRSAVE) { MBBI->eraseFromParent(); // remove it. FoundIt = true; break; } } RemovedAllMTVRSAVEs &= FoundIt; } } // If we found and removed all MTVRSAVE instructions, remove the read of // VRSAVE as well. if (RemovedAllMTVRSAVEs) { MBBI = MI; assert(MBBI != Entry->begin() && "UPDATE_VRSAVE is first instr in block?"); --MBBI; assert(MBBI->getOpcode() == PPC::MFVRSAVE && "VRSAVE instrs wandered?"); MBBI->eraseFromParent(); } // Finally, nuke the UPDATE_VRSAVE. MI->eraseFromParent(); } // HandleVRSaveUpdate - MI is the UPDATE_VRSAVE instruction introduced by the // instruction selector. Based on the vector registers that have been used, // transform this into the appropriate ORI instruction. static void HandleVRSaveUpdate(MachineInstr *MI, const TargetInstrInfo &TII) { MachineFunction *MF = MI->getParent()->getParent(); const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo(); DebugLoc dl = MI->getDebugLoc(); unsigned UsedRegMask = 0; for (unsigned i = 0; i != 32; ++i) if (MF->getRegInfo().isPhysRegUsed(VRRegNo[i])) UsedRegMask |= 1 << (31-i); // Live in and live out values already must be in the mask, so don't bother // marking them. for (MachineRegisterInfo::livein_iterator I = MF->getRegInfo().livein_begin(), E = MF->getRegInfo().livein_end(); I != E; ++I) { unsigned RegNo = TRI->getEncodingValue(I->first); if (VRRegNo[RegNo] == I->first) // If this really is a vector reg. UsedRegMask &= ~(1 << (31-RegNo)); // Doesn't need to be marked. } // Live out registers appear as use operands on return instructions. for (MachineFunction::const_iterator BI = MF->begin(), BE = MF->end(); UsedRegMask != 0 && BI != BE; ++BI) { const MachineBasicBlock &MBB = *BI; if (MBB.empty() || !MBB.back().isReturn()) continue; const MachineInstr &Ret = MBB.back(); for (unsigned I = 0, E = Ret.getNumOperands(); I != E; ++I) { const MachineOperand &MO = Ret.getOperand(I); if (!MO.isReg() || !PPC::VRRCRegClass.contains(MO.getReg())) continue; unsigned RegNo = TRI->getEncodingValue(MO.getReg()); UsedRegMask &= ~(1 << (31-RegNo)); } } // If no registers are used, turn this into a copy. if (UsedRegMask == 0) { // Remove all VRSAVE code. RemoveVRSaveCode(MI); return; } unsigned SrcReg = MI->getOperand(1).getReg(); unsigned DstReg = MI->getOperand(0).getReg(); if ((UsedRegMask & 0xFFFF) == UsedRegMask) { if (DstReg != SrcReg) BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORI), DstReg) .addReg(SrcReg) .addImm(UsedRegMask); else BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORI), DstReg) .addReg(SrcReg, RegState::Kill) .addImm(UsedRegMask); } else if ((UsedRegMask & 0xFFFF0000) == UsedRegMask) { if (DstReg != SrcReg) BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORIS), DstReg) .addReg(SrcReg) .addImm(UsedRegMask >> 16); else BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORIS), DstReg) .addReg(SrcReg, RegState::Kill) .addImm(UsedRegMask >> 16); } else { if (DstReg != SrcReg) BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORIS), DstReg) .addReg(SrcReg) .addImm(UsedRegMask >> 16); else BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORIS), DstReg) .addReg(SrcReg, RegState::Kill) .addImm(UsedRegMask >> 16); BuildMI(*MI->getParent(), MI, dl, TII.get(PPC::ORI), DstReg) .addReg(DstReg, RegState::Kill) .addImm(UsedRegMask & 0xFFFF); } // Remove the old UPDATE_VRSAVE instruction. MI->eraseFromParent(); } static bool spillsCR(const MachineFunction &MF) { const PPCFunctionInfo *FuncInfo = MF.getInfo(); return FuncInfo->isCRSpilled(); } static bool spillsVRSAVE(const MachineFunction &MF) { const PPCFunctionInfo *FuncInfo = MF.getInfo(); return FuncInfo->isVRSAVESpilled(); } static bool hasSpills(const MachineFunction &MF) { const PPCFunctionInfo *FuncInfo = MF.getInfo(); return FuncInfo->hasSpills(); } static bool hasNonRISpills(const MachineFunction &MF) { const PPCFunctionInfo *FuncInfo = MF.getInfo(); return FuncInfo->hasNonRISpills(); } /// determineFrameLayout - Determine the size of the frame and maximum call /// frame size. unsigned PPCFrameLowering::determineFrameLayout(MachineFunction &MF, bool UpdateMF, bool UseEstimate) const { MachineFrameInfo *MFI = MF.getFrameInfo(); // Get the number of bytes to allocate from the FrameInfo unsigned FrameSize = UseEstimate ? MFI->estimateStackSize(MF) : MFI->getStackSize(); // Get stack alignments. The frame must be aligned to the greatest of these: unsigned TargetAlign = getStackAlignment(); // alignment required per the ABI unsigned MaxAlign = MFI->getMaxAlignment(); // algmt required by data in frame unsigned AlignMask = std::max(MaxAlign, TargetAlign) - 1; const PPCRegisterInfo *RegInfo = static_cast(MF.getTarget().getRegisterInfo()); // If we are a leaf function, and use up to 224 bytes of stack space, // don't have a frame pointer, calls, or dynamic alloca then we do not need // to adjust the stack pointer (we fit in the Red Zone). // The 32-bit SVR4 ABI has no Red Zone. However, it can still generate // stackless code if all local vars are reg-allocated. bool DisableRedZone = MF.getFunction()->getAttributes(). hasAttribute(AttributeSet::FunctionIndex, Attribute::NoRedZone); if (!DisableRedZone && (Subtarget.isPPC64() || // 32-bit SVR4, no stack- !Subtarget.isSVR4ABI() || // allocated locals. FrameSize == 0) && FrameSize <= 224 && // Fits in red zone. !MFI->hasVarSizedObjects() && // No dynamic alloca. !MFI->adjustsStack() && // No calls. !RegInfo->hasBasePointer(MF)) { // No special alignment. // No need for frame if (UpdateMF) MFI->setStackSize(0); return 0; } // Get the maximum call frame size of all the calls. unsigned maxCallFrameSize = MFI->getMaxCallFrameSize(); // Maximum call frame needs to be at least big enough for linkage area. unsigned minCallFrameSize = getLinkageSize(Subtarget.isPPC64(), Subtarget.isDarwinABI()); maxCallFrameSize = std::max(maxCallFrameSize, minCallFrameSize); // If we have dynamic alloca then maxCallFrameSize needs to be aligned so // that allocations will be aligned. if (MFI->hasVarSizedObjects()) maxCallFrameSize = (maxCallFrameSize + AlignMask) & ~AlignMask; // Update maximum call frame size. if (UpdateMF) MFI->setMaxCallFrameSize(maxCallFrameSize); // Include call frame size in total. FrameSize += maxCallFrameSize; // Make sure the frame is aligned. FrameSize = (FrameSize + AlignMask) & ~AlignMask; // Update frame info. if (UpdateMF) MFI->setStackSize(FrameSize); return FrameSize; } // hasFP - Return true if the specified function actually has a dedicated frame // pointer register. bool PPCFrameLowering::hasFP(const MachineFunction &MF) const { const MachineFrameInfo *MFI = MF.getFrameInfo(); // FIXME: This is pretty much broken by design: hasFP() might be called really // early, before the stack layout was calculated and thus hasFP() might return // true or false here depending on the time of call. return (MFI->getStackSize()) && needsFP(MF); } // needsFP - Return true if the specified function should have a dedicated frame // pointer register. This is true if the function has variable sized allocas or // if frame pointer elimination is disabled. bool PPCFrameLowering::needsFP(const MachineFunction &MF) const { const MachineFrameInfo *MFI = MF.getFrameInfo(); // Naked functions have no stack frame pushed, so we don't have a frame // pointer. if (MF.getFunction()->getAttributes().hasAttribute( AttributeSet::FunctionIndex, Attribute::Naked)) return false; return MF.getTarget().Options.DisableFramePointerElim(MF) || MFI->hasVarSizedObjects() || (MF.getTarget().Options.GuaranteedTailCallOpt && MF.getInfo()->hasFastCall()); } void PPCFrameLowering::replaceFPWithRealFP(MachineFunction &MF) const { bool is31 = needsFP(MF); unsigned FPReg = is31 ? PPC::R31 : PPC::R1; unsigned FP8Reg = is31 ? PPC::X31 : PPC::X1; const PPCRegisterInfo *RegInfo = static_cast(MF.getTarget().getRegisterInfo()); bool HasBP = RegInfo->hasBasePointer(MF); unsigned BPReg = HasBP ? (unsigned) RegInfo->getBaseRegister(MF) : FPReg; unsigned BP8Reg = HasBP ? (unsigned) PPC::X30 : FPReg; for (MachineFunction::iterator BI = MF.begin(), BE = MF.end(); BI != BE; ++BI) for (MachineBasicBlock::iterator MBBI = BI->end(); MBBI != BI->begin(); ) { --MBBI; for (unsigned I = 0, E = MBBI->getNumOperands(); I != E; ++I) { MachineOperand &MO = MBBI->getOperand(I); if (!MO.isReg()) continue; switch (MO.getReg()) { case PPC::FP: MO.setReg(FPReg); break; case PPC::FP8: MO.setReg(FP8Reg); break; case PPC::BP: MO.setReg(BPReg); break; case PPC::BP8: MO.setReg(BP8Reg); break; } } } } void PPCFrameLowering::emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB MachineBasicBlock::iterator MBBI = MBB.begin(); MachineFrameInfo *MFI = MF.getFrameInfo(); const PPCInstrInfo &TII = *static_cast(MF.getTarget().getInstrInfo()); const PPCRegisterInfo *RegInfo = static_cast(MF.getTarget().getRegisterInfo()); MachineModuleInfo &MMI = MF.getMMI(); const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo(); DebugLoc dl; bool needsFrameMoves = MMI.hasDebugInfo() || MF.getFunction()->needsUnwindTableEntry(); bool isPIC = MF.getTarget().getRelocationModel() == Reloc::PIC_; // Get processor type. bool isPPC64 = Subtarget.isPPC64(); // Get the ABI. bool isDarwinABI = Subtarget.isDarwinABI(); bool isSVR4ABI = Subtarget.isSVR4ABI(); assert((isDarwinABI || isSVR4ABI) && "Currently only Darwin and SVR4 ABIs are supported for PowerPC."); // Scan the prolog, looking for an UPDATE_VRSAVE instruction. If we find it, // process it. if (!isSVR4ABI) for (unsigned i = 0; MBBI != MBB.end(); ++i, ++MBBI) { if (MBBI->getOpcode() == PPC::UPDATE_VRSAVE) { HandleVRSaveUpdate(MBBI, TII); break; } } // Move MBBI back to the beginning of the function. MBBI = MBB.begin(); // Work out frame sizes. unsigned FrameSize = determineFrameLayout(MF); int NegFrameSize = -FrameSize; if (!isInt<32>(NegFrameSize)) llvm_unreachable("Unhandled stack size!"); if (MFI->isFrameAddressTaken()) replaceFPWithRealFP(MF); // Check if the link register (LR) must be saved. PPCFunctionInfo *FI = MF.getInfo(); bool MustSaveLR = FI->mustSaveLR(); const SmallVectorImpl &MustSaveCRs = FI->getMustSaveCRs(); // Do we have a frame pointer and/or base pointer for this function? bool HasFP = hasFP(MF); bool HasBP = RegInfo->hasBasePointer(MF); unsigned SPReg = isPPC64 ? PPC::X1 : PPC::R1; unsigned BPReg = RegInfo->getBaseRegister(MF); unsigned FPReg = isPPC64 ? PPC::X31 : PPC::R31; unsigned LRReg = isPPC64 ? PPC::LR8 : PPC::LR; unsigned ScratchReg = isPPC64 ? PPC::X0 : PPC::R0; unsigned TempReg = isPPC64 ? PPC::X12 : PPC::R12; // another scratch reg // ...(R12/X12 is volatile in both Darwin & SVR4, & can't be a function arg.) const MCInstrDesc& MFLRInst = TII.get(isPPC64 ? PPC::MFLR8 : PPC::MFLR ); const MCInstrDesc& StoreInst = TII.get(isPPC64 ? PPC::STD : PPC::STW ); const MCInstrDesc& StoreUpdtInst = TII.get(isPPC64 ? PPC::STDU : PPC::STWU ); const MCInstrDesc& StoreUpdtIdxInst = TII.get(isPPC64 ? PPC::STDUX : PPC::STWUX); const MCInstrDesc& LoadImmShiftedInst = TII.get(isPPC64 ? PPC::LIS8 : PPC::LIS ); const MCInstrDesc& OrImmInst = TII.get(isPPC64 ? PPC::ORI8 : PPC::ORI ); const MCInstrDesc& OrInst = TII.get(isPPC64 ? PPC::OR8 : PPC::OR ); const MCInstrDesc& SubtractCarryingInst = TII.get(isPPC64 ? PPC::SUBFC8 : PPC::SUBFC); const MCInstrDesc& SubtractImmCarryingInst = TII.get(isPPC64 ? PPC::SUBFIC8 : PPC::SUBFIC); // Regarding this assert: Even though LR is saved in the caller's frame (i.e., // LROffset is positive), that slot is callee-owned. Because PPC32 SVR4 has no // Red Zone, an asynchronous event (a form of "callee") could claim a frame & // overwrite it, so PPC32 SVR4 must claim at least a minimal frame to save LR. assert((isPPC64 || !isSVR4ABI || !(!FrameSize && (MustSaveLR || HasFP))) && "FrameSize must be >0 to save/restore the FP or LR for 32-bit SVR4."); int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI); int FPOffset = 0; if (HasFP) { if (isSVR4ABI) { MachineFrameInfo *FFI = MF.getFrameInfo(); int FPIndex = FI->getFramePointerSaveIndex(); assert(FPIndex && "No Frame Pointer Save Slot!"); FPOffset = FFI->getObjectOffset(FPIndex); } else { FPOffset = PPCFrameLowering::getFramePointerSaveOffset(isPPC64, isDarwinABI); } } int BPOffset = 0; if (HasBP) { if (isSVR4ABI) { MachineFrameInfo *FFI = MF.getFrameInfo(); int BPIndex = FI->getBasePointerSaveIndex(); assert(BPIndex && "No Base Pointer Save Slot!"); BPOffset = FFI->getObjectOffset(BPIndex); } else { BPOffset = PPCFrameLowering::getBasePointerSaveOffset(isPPC64, isDarwinABI, isPIC); } } // Get stack alignments. unsigned MaxAlign = MFI->getMaxAlignment(); if (HasBP && MaxAlign > 1) assert(isPowerOf2_32(MaxAlign) && isInt<16>(MaxAlign) && "Invalid alignment!"); // Frames of 32KB & larger require special handling because they cannot be // indexed into with a simple STDU/STWU/STD/STW immediate offset operand. bool isLargeFrame = !isInt<16>(NegFrameSize); if (MustSaveLR) BuildMI(MBB, MBBI, dl, MFLRInst, ScratchReg); assert((isPPC64 || MustSaveCRs.empty()) && "Prologue CR saving supported only in 64-bit mode"); if (!MustSaveCRs.empty()) { // will only occur for PPC64 MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(PPC::MFCR8), TempReg); for (unsigned i = 0, e = MustSaveCRs.size(); i != e; ++i) MIB.addReg(MustSaveCRs[i], RegState::ImplicitKill); } if (HasFP) // FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe. BuildMI(MBB, MBBI, dl, StoreInst) .addReg(FPReg) .addImm(FPOffset) .addReg(SPReg); if (HasBP) // FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe. BuildMI(MBB, MBBI, dl, StoreInst) .addReg(BPReg) .addImm(BPOffset) .addReg(SPReg); if (MustSaveLR) // FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe. BuildMI(MBB, MBBI, dl, StoreInst) .addReg(ScratchReg) .addImm(LROffset) .addReg(SPReg); if (!MustSaveCRs.empty()) // will only occur for PPC64 BuildMI(MBB, MBBI, dl, TII.get(PPC::STW8)) .addReg(TempReg, getKillRegState(true)) .addImm(8) .addReg(SPReg); // Skip the rest if this is a leaf function & all spills fit in the Red Zone. if (!FrameSize) return; // Adjust stack pointer: r1 += NegFrameSize. // If there is a preferred stack alignment, align R1 now if (HasBP) { // Save a copy of r1 as the base pointer. BuildMI(MBB, MBBI, dl, OrInst, BPReg) .addReg(SPReg) .addReg(SPReg); } if (HasBP && MaxAlign > 1) { if (isPPC64) BuildMI(MBB, MBBI, dl, TII.get(PPC::RLDICL), ScratchReg) .addReg(SPReg) .addImm(0) .addImm(64 - Log2_32(MaxAlign)); else // PPC32... BuildMI(MBB, MBBI, dl, TII.get(PPC::RLWINM), ScratchReg) .addReg(SPReg) .addImm(0) .addImm(32 - Log2_32(MaxAlign)) .addImm(31); if (!isLargeFrame) { BuildMI(MBB, MBBI, dl, SubtractImmCarryingInst, ScratchReg) .addReg(ScratchReg, RegState::Kill) .addImm(NegFrameSize); } else { BuildMI(MBB, MBBI, dl, LoadImmShiftedInst, TempReg) .addImm(NegFrameSize >> 16); BuildMI(MBB, MBBI, dl, OrImmInst, TempReg) .addReg(TempReg, RegState::Kill) .addImm(NegFrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, SubtractCarryingInst, ScratchReg) .addReg(ScratchReg, RegState::Kill) .addReg(TempReg, RegState::Kill); } BuildMI(MBB, MBBI, dl, StoreUpdtIdxInst, SPReg) .addReg(SPReg, RegState::Kill) .addReg(SPReg) .addReg(ScratchReg); } else if (!isLargeFrame) { BuildMI(MBB, MBBI, dl, StoreUpdtInst, SPReg) .addReg(SPReg) .addImm(NegFrameSize) .addReg(SPReg); } else { BuildMI(MBB, MBBI, dl, LoadImmShiftedInst, ScratchReg) .addImm(NegFrameSize >> 16); BuildMI(MBB, MBBI, dl, OrImmInst, ScratchReg) .addReg(ScratchReg, RegState::Kill) .addImm(NegFrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, StoreUpdtIdxInst, SPReg) .addReg(SPReg, RegState::Kill) .addReg(SPReg) .addReg(ScratchReg); } // Add the "machine moves" for the instructions we generated above, but in // reverse order. if (needsFrameMoves) { // Show update of SP. assert(NegFrameSize); unsigned CFIIndex = MMI.addFrameInst( MCCFIInstruction::createDefCfaOffset(nullptr, NegFrameSize)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); if (HasFP) { unsigned Reg = MRI->getDwarfRegNum(FPReg, true); CFIIndex = MMI.addFrameInst( MCCFIInstruction::createOffset(nullptr, Reg, FPOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); } if (HasBP) { unsigned Reg = MRI->getDwarfRegNum(BPReg, true); CFIIndex = MMI.addFrameInst( MCCFIInstruction::createOffset(nullptr, Reg, BPOffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); } if (MustSaveLR) { unsigned Reg = MRI->getDwarfRegNum(LRReg, true); CFIIndex = MMI.addFrameInst( MCCFIInstruction::createOffset(nullptr, Reg, LROffset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); } } // If there is a frame pointer, copy R1 into R31 if (HasFP) { BuildMI(MBB, MBBI, dl, OrInst, FPReg) .addReg(SPReg) .addReg(SPReg); if (needsFrameMoves) { // Mark effective beginning of when frame pointer is ready. unsigned Reg = MRI->getDwarfRegNum(FPReg, true); unsigned CFIIndex = MMI.addFrameInst( MCCFIInstruction::createDefCfaRegister(nullptr, Reg)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); } } if (needsFrameMoves) { // Add callee saved registers to move list. const std::vector &CSI = MFI->getCalleeSavedInfo(); for (unsigned I = 0, E = CSI.size(); I != E; ++I) { unsigned Reg = CSI[I].getReg(); if (Reg == PPC::LR || Reg == PPC::LR8 || Reg == PPC::RM) continue; // This is a bit of a hack: CR2LT, CR2GT, CR2EQ and CR2UN are just // subregisters of CR2. We just need to emit a move of CR2. if (PPC::CRBITRCRegClass.contains(Reg)) continue; // For SVR4, don't emit a move for the CR spill slot if we haven't // spilled CRs. if (isSVR4ABI && (PPC::CR2 <= Reg && Reg <= PPC::CR4) && MustSaveCRs.empty()) continue; // For 64-bit SVR4 when we have spilled CRs, the spill location // is SP+8, not a frame-relative slot. if (isSVR4ABI && isPPC64 && (PPC::CR2 <= Reg && Reg <= PPC::CR4)) { unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( nullptr, MRI->getDwarfRegNum(PPC::CR2, true), 8)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); continue; } int Offset = MFI->getObjectOffset(CSI[I].getFrameIdx()); unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( nullptr, MRI->getDwarfRegNum(Reg, true), Offset)); BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) .addCFIIndex(CFIIndex); } } } void PPCFrameLowering::emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const { MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr(); assert(MBBI != MBB.end() && "Returning block has no terminator"); const PPCInstrInfo &TII = *static_cast(MF.getTarget().getInstrInfo()); const PPCRegisterInfo *RegInfo = static_cast(MF.getTarget().getRegisterInfo()); unsigned RetOpcode = MBBI->getOpcode(); DebugLoc dl; assert((RetOpcode == PPC::BLR || RetOpcode == PPC::TCRETURNri || RetOpcode == PPC::TCRETURNdi || RetOpcode == PPC::TCRETURNai || RetOpcode == PPC::TCRETURNri8 || RetOpcode == PPC::TCRETURNdi8 || RetOpcode == PPC::TCRETURNai8) && "Can only insert epilog into returning blocks"); // Get alignment info so we know how to restore the SP. const MachineFrameInfo *MFI = MF.getFrameInfo(); // Get the number of bytes allocated from the FrameInfo. int FrameSize = MFI->getStackSize(); // Get processor type. bool isPPC64 = Subtarget.isPPC64(); // Get the ABI. bool isDarwinABI = Subtarget.isDarwinABI(); bool isSVR4ABI = Subtarget.isSVR4ABI(); bool isPIC = MF.getTarget().getRelocationModel() == Reloc::PIC_; // Check if the link register (LR) has been saved. PPCFunctionInfo *FI = MF.getInfo(); bool MustSaveLR = FI->mustSaveLR(); const SmallVectorImpl &MustSaveCRs = FI->getMustSaveCRs(); // Do we have a frame pointer and/or base pointer for this function? bool HasFP = hasFP(MF); bool HasBP = RegInfo->hasBasePointer(MF); unsigned SPReg = isPPC64 ? PPC::X1 : PPC::R1; unsigned BPReg = RegInfo->getBaseRegister(MF); unsigned FPReg = isPPC64 ? PPC::X31 : PPC::R31; unsigned ScratchReg = isPPC64 ? PPC::X0 : PPC::R0; unsigned TempReg = isPPC64 ? PPC::X12 : PPC::R12; // another scratch reg const MCInstrDesc& MTLRInst = TII.get( isPPC64 ? PPC::MTLR8 : PPC::MTLR ); const MCInstrDesc& LoadInst = TII.get( isPPC64 ? PPC::LD : PPC::LWZ ); const MCInstrDesc& LoadImmShiftedInst = TII.get( isPPC64 ? PPC::LIS8 : PPC::LIS ); const MCInstrDesc& OrImmInst = TII.get( isPPC64 ? PPC::ORI8 : PPC::ORI ); const MCInstrDesc& AddImmInst = TII.get( isPPC64 ? PPC::ADDI8 : PPC::ADDI ); const MCInstrDesc& AddInst = TII.get( isPPC64 ? PPC::ADD8 : PPC::ADD4 ); int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI); int FPOffset = 0; if (HasFP) { if (isSVR4ABI) { MachineFrameInfo *FFI = MF.getFrameInfo(); int FPIndex = FI->getFramePointerSaveIndex(); assert(FPIndex && "No Frame Pointer Save Slot!"); FPOffset = FFI->getObjectOffset(FPIndex); } else { FPOffset = PPCFrameLowering::getFramePointerSaveOffset(isPPC64, isDarwinABI); } } int BPOffset = 0; if (HasBP) { if (isSVR4ABI) { MachineFrameInfo *FFI = MF.getFrameInfo(); int BPIndex = FI->getBasePointerSaveIndex(); assert(BPIndex && "No Base Pointer Save Slot!"); BPOffset = FFI->getObjectOffset(BPIndex); } else { BPOffset = PPCFrameLowering::getBasePointerSaveOffset(isPPC64, isDarwinABI, isPIC); } } bool UsesTCRet = RetOpcode == PPC::TCRETURNri || RetOpcode == PPC::TCRETURNdi || RetOpcode == PPC::TCRETURNai || RetOpcode == PPC::TCRETURNri8 || RetOpcode == PPC::TCRETURNdi8 || RetOpcode == PPC::TCRETURNai8; if (UsesTCRet) { int MaxTCRetDelta = FI->getTailCallSPDelta(); MachineOperand &StackAdjust = MBBI->getOperand(1); assert(StackAdjust.isImm() && "Expecting immediate value."); // Adjust stack pointer. int StackAdj = StackAdjust.getImm(); int Delta = StackAdj - MaxTCRetDelta; assert((Delta >= 0) && "Delta must be positive"); if (MaxTCRetDelta>0) FrameSize += (StackAdj +Delta); else FrameSize += StackAdj; } // Frames of 32KB & larger require special handling because they cannot be // indexed into with a simple LD/LWZ immediate offset operand. bool isLargeFrame = !isInt<16>(FrameSize); if (FrameSize) { // In the prologue, the loaded (or persistent) stack pointer value is offset // by the STDU/STDUX/STWU/STWUX instruction. Add this offset back now. // If this function contained a fastcc call and GuaranteedTailCallOpt is // enabled (=> hasFastCall()==true) the fastcc call might contain a tail // call which invalidates the stack pointer value in SP(0). So we use the // value of R31 in this case. if (FI->hasFastCall()) { assert(HasFP && "Expecting a valid frame pointer."); if (!isLargeFrame) { BuildMI(MBB, MBBI, dl, AddImmInst, SPReg) .addReg(FPReg).addImm(FrameSize); } else { BuildMI(MBB, MBBI, dl, LoadImmShiftedInst, ScratchReg) .addImm(FrameSize >> 16); BuildMI(MBB, MBBI, dl, OrImmInst, ScratchReg) .addReg(ScratchReg, RegState::Kill) .addImm(FrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, AddInst) .addReg(SPReg) .addReg(FPReg) .addReg(ScratchReg); } } else if (!isLargeFrame && !HasBP && !MFI->hasVarSizedObjects()) { BuildMI(MBB, MBBI, dl, AddImmInst, SPReg) .addReg(SPReg) .addImm(FrameSize); } else { BuildMI(MBB, MBBI, dl, LoadInst, SPReg) .addImm(0) .addReg(SPReg); } } if (MustSaveLR) BuildMI(MBB, MBBI, dl, LoadInst, ScratchReg) .addImm(LROffset) .addReg(SPReg); assert((isPPC64 || MustSaveCRs.empty()) && "Epilogue CR restoring supported only in 64-bit mode"); if (!MustSaveCRs.empty()) // will only occur for PPC64 BuildMI(MBB, MBBI, dl, TII.get(PPC::LWZ8), TempReg) .addImm(8) .addReg(SPReg); if (HasFP) BuildMI(MBB, MBBI, dl, LoadInst, FPReg) .addImm(FPOffset) .addReg(SPReg); if (HasBP) BuildMI(MBB, MBBI, dl, LoadInst, BPReg) .addImm(BPOffset) .addReg(SPReg); if (!MustSaveCRs.empty()) // will only occur for PPC64 for (unsigned i = 0, e = MustSaveCRs.size(); i != e; ++i) BuildMI(MBB, MBBI, dl, TII.get(PPC::MTOCRF8), MustSaveCRs[i]) .addReg(TempReg, getKillRegState(i == e-1)); if (MustSaveLR) BuildMI(MBB, MBBI, dl, MTLRInst).addReg(ScratchReg); // Callee pop calling convention. Pop parameter/linkage area. Used for tail // call optimization if (MF.getTarget().Options.GuaranteedTailCallOpt && RetOpcode == PPC::BLR && MF.getFunction()->getCallingConv() == CallingConv::Fast) { PPCFunctionInfo *FI = MF.getInfo(); unsigned CallerAllocatedAmt = FI->getMinReservedArea(); if (CallerAllocatedAmt && isInt<16>(CallerAllocatedAmt)) { BuildMI(MBB, MBBI, dl, AddImmInst, SPReg) .addReg(SPReg).addImm(CallerAllocatedAmt); } else { BuildMI(MBB, MBBI, dl, LoadImmShiftedInst, ScratchReg) .addImm(CallerAllocatedAmt >> 16); BuildMI(MBB, MBBI, dl, OrImmInst, ScratchReg) .addReg(ScratchReg, RegState::Kill) .addImm(CallerAllocatedAmt & 0xFFFF); BuildMI(MBB, MBBI, dl, AddInst) .addReg(SPReg) .addReg(FPReg) .addReg(ScratchReg); } } else if (RetOpcode == PPC::TCRETURNdi) { MBBI = MBB.getLastNonDebugInstr(); MachineOperand &JumpTarget = MBBI->getOperand(0); BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILB)). addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset()); } else if (RetOpcode == PPC::TCRETURNri) { MBBI = MBB.getLastNonDebugInstr(); assert(MBBI->getOperand(0).isReg() && "Expecting register operand."); BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBCTR)); } else if (RetOpcode == PPC::TCRETURNai) { MBBI = MBB.getLastNonDebugInstr(); MachineOperand &JumpTarget = MBBI->getOperand(0); BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBA)).addImm(JumpTarget.getImm()); } else if (RetOpcode == PPC::TCRETURNdi8) { MBBI = MBB.getLastNonDebugInstr(); MachineOperand &JumpTarget = MBBI->getOperand(0); BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILB8)). addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset()); } else if (RetOpcode == PPC::TCRETURNri8) { MBBI = MBB.getLastNonDebugInstr(); assert(MBBI->getOperand(0).isReg() && "Expecting register operand."); BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBCTR8)); } else if (RetOpcode == PPC::TCRETURNai8) { MBBI = MBB.getLastNonDebugInstr(); MachineOperand &JumpTarget = MBBI->getOperand(0); BuildMI(MBB, MBBI, dl, TII.get(PPC::TAILBA8)).addImm(JumpTarget.getImm()); } } /// MustSaveLR - Return true if this function requires that we save the LR /// register onto the stack in the prolog and restore it in the epilog of the /// function. static bool MustSaveLR(const MachineFunction &MF, unsigned LR) { const PPCFunctionInfo *MFI = MF.getInfo(); // We need a save/restore of LR if there is any def of LR (which is // defined by calls, including the PIC setup sequence), or if there is // some use of the LR stack slot (e.g. for builtin_return_address). // (LR comes in 32 and 64 bit versions.) MachineRegisterInfo::def_iterator RI = MF.getRegInfo().def_begin(LR); return RI !=MF.getRegInfo().def_end() || MFI->isLRStoreRequired(); } void PPCFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, RegScavenger *) const { const PPCRegisterInfo *RegInfo = static_cast(MF.getTarget().getRegisterInfo()); // Save and clear the LR state. PPCFunctionInfo *FI = MF.getInfo(); unsigned LR = RegInfo->getRARegister(); FI->setMustSaveLR(MustSaveLR(MF, LR)); MachineRegisterInfo &MRI = MF.getRegInfo(); MRI.setPhysRegUnused(LR); // Save R31 if necessary int FPSI = FI->getFramePointerSaveIndex(); bool isPPC64 = Subtarget.isPPC64(); bool isDarwinABI = Subtarget.isDarwinABI(); bool isPIC = MF.getTarget().getRelocationModel() == Reloc::PIC_; MachineFrameInfo *MFI = MF.getFrameInfo(); // If the frame pointer save index hasn't been defined yet. if (!FPSI && needsFP(MF)) { // Find out what the fix offset of the frame pointer save area. int FPOffset = getFramePointerSaveOffset(isPPC64, isDarwinABI); // Allocate the frame index for frame pointer save area. FPSI = MFI->CreateFixedObject(isPPC64? 8 : 4, FPOffset, true); // Save the result. FI->setFramePointerSaveIndex(FPSI); } int BPSI = FI->getBasePointerSaveIndex(); if (!BPSI && RegInfo->hasBasePointer(MF)) { int BPOffset = getBasePointerSaveOffset(isPPC64, isDarwinABI, isPIC); // Allocate the frame index for the base pointer save area. BPSI = MFI->CreateFixedObject(isPPC64? 8 : 4, BPOffset, true); // Save the result. FI->setBasePointerSaveIndex(BPSI); } // Reserve stack space to move the linkage area to in case of a tail call. int TCSPDelta = 0; if (MF.getTarget().Options.GuaranteedTailCallOpt && (TCSPDelta = FI->getTailCallSPDelta()) < 0) { MFI->CreateFixedObject(-1 * TCSPDelta, TCSPDelta, true); } // For 32-bit SVR4, allocate the nonvolatile CR spill slot iff the // function uses CR 2, 3, or 4. if (!isPPC64 && !isDarwinABI && (MRI.isPhysRegUsed(PPC::CR2) || MRI.isPhysRegUsed(PPC::CR3) || MRI.isPhysRegUsed(PPC::CR4))) { int FrameIdx = MFI->CreateFixedObject((uint64_t)4, (int64_t)-4, true); FI->setCRSpillFrameIndex(FrameIdx); } } void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF, RegScavenger *RS) const { // Early exit if not using the SVR4 ABI. if (!Subtarget.isSVR4ABI()) { addScavengingSpillSlot(MF, RS); return; } // Get callee saved register information. MachineFrameInfo *FFI = MF.getFrameInfo(); const std::vector &CSI = FFI->getCalleeSavedInfo(); // Early exit if no callee saved registers are modified! if (CSI.empty() && !needsFP(MF)) { addScavengingSpillSlot(MF, RS); return; } unsigned MinGPR = PPC::R31; unsigned MinG8R = PPC::X31; unsigned MinFPR = PPC::F31; unsigned MinVR = PPC::V31; bool HasGPSaveArea = false; bool HasG8SaveArea = false; bool HasFPSaveArea = false; bool HasVRSAVESaveArea = false; bool HasVRSaveArea = false; SmallVector GPRegs; SmallVector G8Regs; SmallVector FPRegs; SmallVector VRegs; for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); if (PPC::GPRCRegClass.contains(Reg)) { HasGPSaveArea = true; GPRegs.push_back(CSI[i]); if (Reg < MinGPR) { MinGPR = Reg; } } else if (PPC::G8RCRegClass.contains(Reg)) { HasG8SaveArea = true; G8Regs.push_back(CSI[i]); if (Reg < MinG8R) { MinG8R = Reg; } } else if (PPC::F8RCRegClass.contains(Reg)) { HasFPSaveArea = true; FPRegs.push_back(CSI[i]); if (Reg < MinFPR) { MinFPR = Reg; } } else if (PPC::CRBITRCRegClass.contains(Reg) || PPC::CRRCRegClass.contains(Reg)) { ; // do nothing, as we already know whether CRs are spilled } else if (PPC::VRSAVERCRegClass.contains(Reg)) { HasVRSAVESaveArea = true; } else if (PPC::VRRCRegClass.contains(Reg)) { HasVRSaveArea = true; VRegs.push_back(CSI[i]); if (Reg < MinVR) { MinVR = Reg; } } else { llvm_unreachable("Unknown RegisterClass!"); } } PPCFunctionInfo *PFI = MF.getInfo(); const TargetRegisterInfo *TRI = MF.getTarget().getRegisterInfo(); int64_t LowerBound = 0; // Take into account stack space reserved for tail calls. int TCSPDelta = 0; if (MF.getTarget().Options.GuaranteedTailCallOpt && (TCSPDelta = PFI->getTailCallSPDelta()) < 0) { LowerBound = TCSPDelta; } // The Floating-point register save area is right below the back chain word // of the previous stack frame. if (HasFPSaveArea) { for (unsigned i = 0, e = FPRegs.size(); i != e; ++i) { int FI = FPRegs[i].getFrameIdx(); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } LowerBound -= (31 - TRI->getEncodingValue(MinFPR) + 1) * 8; } // Check whether the frame pointer register is allocated. If so, make sure it // is spilled to the correct offset. if (needsFP(MF)) { HasGPSaveArea = true; int FI = PFI->getFramePointerSaveIndex(); assert(FI && "No Frame Pointer Save Slot!"); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } const PPCRegisterInfo *RegInfo = static_cast(MF.getTarget().getRegisterInfo()); if (RegInfo->hasBasePointer(MF)) { HasGPSaveArea = true; int FI = PFI->getBasePointerSaveIndex(); assert(FI && "No Base Pointer Save Slot!"); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } // General register save area starts right below the Floating-point // register save area. if (HasGPSaveArea || HasG8SaveArea) { // Move general register save area spill slots down, taking into account // the size of the Floating-point register save area. for (unsigned i = 0, e = GPRegs.size(); i != e; ++i) { int FI = GPRegs[i].getFrameIdx(); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } // Move general register save area spill slots down, taking into account // the size of the Floating-point register save area. for (unsigned i = 0, e = G8Regs.size(); i != e; ++i) { int FI = G8Regs[i].getFrameIdx(); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } unsigned MinReg = std::min(TRI->getEncodingValue(MinGPR), TRI->getEncodingValue(MinG8R)); if (Subtarget.isPPC64()) { LowerBound -= (31 - MinReg + 1) * 8; } else { LowerBound -= (31 - MinReg + 1) * 4; } } // For 32-bit only, the CR save area is below the general register // save area. For 64-bit SVR4, the CR save area is addressed relative // to the stack pointer and hence does not need an adjustment here. // Only CR2 (the first nonvolatile spilled) has an associated frame // index so that we have a single uniform save area. if (spillsCR(MF) && !(Subtarget.isPPC64() && Subtarget.isSVR4ABI())) { // Adjust the frame index of the CR spill slot. for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); if ((Subtarget.isSVR4ABI() && Reg == PPC::CR2) // Leave Darwin logic as-is. || (!Subtarget.isSVR4ABI() && (PPC::CRBITRCRegClass.contains(Reg) || PPC::CRRCRegClass.contains(Reg)))) { int FI = CSI[i].getFrameIdx(); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } } LowerBound -= 4; // The CR save area is always 4 bytes long. } if (HasVRSAVESaveArea) { // FIXME SVR4: Is it actually possible to have multiple elements in CSI // which have the VRSAVE register class? // Adjust the frame index of the VRSAVE spill slot. for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); if (PPC::VRSAVERCRegClass.contains(Reg)) { int FI = CSI[i].getFrameIdx(); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } } LowerBound -= 4; // The VRSAVE save area is always 4 bytes long. } if (HasVRSaveArea) { // Insert alignment padding, we need 16-byte alignment. LowerBound = (LowerBound - 15) & ~(15); for (unsigned i = 0, e = VRegs.size(); i != e; ++i) { int FI = VRegs[i].getFrameIdx(); FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); } } addScavengingSpillSlot(MF, RS); } void PPCFrameLowering::addScavengingSpillSlot(MachineFunction &MF, RegScavenger *RS) const { // Reserve a slot closest to SP or frame pointer if we have a dynalloc or // a large stack, which will require scavenging a register to materialize a // large offset. // We need to have a scavenger spill slot for spills if the frame size is // large. In case there is no free register for large-offset addressing, // this slot is used for the necessary emergency spill. Also, we need the // slot for dynamic stack allocations. // The scavenger might be invoked if the frame offset does not fit into // the 16-bit immediate. We don't know the complete frame size here // because we've not yet computed callee-saved register spills or the // needed alignment padding. unsigned StackSize = determineFrameLayout(MF, false, true); MachineFrameInfo *MFI = MF.getFrameInfo(); if (MFI->hasVarSizedObjects() || spillsCR(MF) || spillsVRSAVE(MF) || hasNonRISpills(MF) || (hasSpills(MF) && !isInt<16>(StackSize))) { const TargetRegisterClass *GPRC = &PPC::GPRCRegClass; const TargetRegisterClass *G8RC = &PPC::G8RCRegClass; const TargetRegisterClass *RC = Subtarget.isPPC64() ? G8RC : GPRC; RS->addScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(), RC->getAlignment(), false)); // Might we have over-aligned allocas? bool HasAlVars = MFI->hasVarSizedObjects() && MFI->getMaxAlignment() > getStackAlignment(); // These kinds of spills might need two registers. if (spillsCR(MF) || spillsVRSAVE(MF) || HasAlVars) RS->addScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(), RC->getAlignment(), false)); } } bool PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, const std::vector &CSI, const TargetRegisterInfo *TRI) const { // Currently, this function only handles SVR4 32- and 64-bit ABIs. // Return false otherwise to maintain pre-existing behavior. if (!Subtarget.isSVR4ABI()) return false; MachineFunction *MF = MBB.getParent(); const PPCInstrInfo &TII = *static_cast(MF->getTarget().getInstrInfo()); DebugLoc DL; bool CRSpilled = false; MachineInstrBuilder CRMIB; for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); // Only Darwin actually uses the VRSAVE register, but it can still appear // here if, for example, @llvm.eh.unwind.init() is used. If we're not on // Darwin, ignore it. if (Reg == PPC::VRSAVE && !Subtarget.isDarwinABI()) continue; // CR2 through CR4 are the nonvolatile CR fields. bool IsCRField = PPC::CR2 <= Reg && Reg <= PPC::CR4; // Add the callee-saved register as live-in; it's killed at the spill. MBB.addLiveIn(Reg); if (CRSpilled && IsCRField) { CRMIB.addReg(Reg, RegState::ImplicitKill); continue; } // Insert the spill to the stack frame. if (IsCRField) { PPCFunctionInfo *FuncInfo = MF->getInfo(); if (Subtarget.isPPC64()) { // The actual spill will happen at the start of the prologue. FuncInfo->addMustSaveCR(Reg); } else { CRSpilled = true; FuncInfo->setSpillsCR(); // 32-bit: FP-relative. Note that we made sure CR2-CR4 all have // the same frame index in PPCRegisterInfo::hasReservedSpillSlot. CRMIB = BuildMI(*MF, DL, TII.get(PPC::MFCR), PPC::R12) .addReg(Reg, RegState::ImplicitKill); MBB.insert(MI, CRMIB); MBB.insert(MI, addFrameReference(BuildMI(*MF, DL, TII.get(PPC::STW)) .addReg(PPC::R12, getKillRegState(true)), CSI[i].getFrameIdx())); } } else { const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.storeRegToStackSlot(MBB, MI, Reg, true, CSI[i].getFrameIdx(), RC, TRI); } } return true; } static void restoreCRs(bool isPPC64, bool is31, bool CR2Spilled, bool CR3Spilled, bool CR4Spilled, MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, const std::vector &CSI, unsigned CSIIndex) { MachineFunction *MF = MBB.getParent(); const PPCInstrInfo &TII = *static_cast(MF->getTarget().getInstrInfo()); DebugLoc DL; unsigned RestoreOp, MoveReg; if (isPPC64) // This is handled during epilogue generation. return; else { // 32-bit: FP-relative MBB.insert(MI, addFrameReference(BuildMI(*MF, DL, TII.get(PPC::LWZ), PPC::R12), CSI[CSIIndex].getFrameIdx())); RestoreOp = PPC::MTOCRF; MoveReg = PPC::R12; } if (CR2Spilled) MBB.insert(MI, BuildMI(*MF, DL, TII.get(RestoreOp), PPC::CR2) .addReg(MoveReg, getKillRegState(!CR3Spilled && !CR4Spilled))); if (CR3Spilled) MBB.insert(MI, BuildMI(*MF, DL, TII.get(RestoreOp), PPC::CR3) .addReg(MoveReg, getKillRegState(!CR4Spilled))); if (CR4Spilled) MBB.insert(MI, BuildMI(*MF, DL, TII.get(RestoreOp), PPC::CR4) .addReg(MoveReg, getKillRegState(true))); } void PPCFrameLowering:: eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const { const PPCInstrInfo &TII = *static_cast(MF.getTarget().getInstrInfo()); if (MF.getTarget().Options.GuaranteedTailCallOpt && I->getOpcode() == PPC::ADJCALLSTACKUP) { // Add (actually subtract) back the amount the callee popped on return. if (int CalleeAmt = I->getOperand(1).getImm()) { bool is64Bit = Subtarget.isPPC64(); CalleeAmt *= -1; unsigned StackReg = is64Bit ? PPC::X1 : PPC::R1; unsigned TmpReg = is64Bit ? PPC::X0 : PPC::R0; unsigned ADDIInstr = is64Bit ? PPC::ADDI8 : PPC::ADDI; unsigned ADDInstr = is64Bit ? PPC::ADD8 : PPC::ADD4; unsigned LISInstr = is64Bit ? PPC::LIS8 : PPC::LIS; unsigned ORIInstr = is64Bit ? PPC::ORI8 : PPC::ORI; MachineInstr *MI = I; DebugLoc dl = MI->getDebugLoc(); if (isInt<16>(CalleeAmt)) { BuildMI(MBB, I, dl, TII.get(ADDIInstr), StackReg) .addReg(StackReg, RegState::Kill) .addImm(CalleeAmt); } else { MachineBasicBlock::iterator MBBI = I; BuildMI(MBB, MBBI, dl, TII.get(LISInstr), TmpReg) .addImm(CalleeAmt >> 16); BuildMI(MBB, MBBI, dl, TII.get(ORIInstr), TmpReg) .addReg(TmpReg, RegState::Kill) .addImm(CalleeAmt & 0xFFFF); BuildMI(MBB, MBBI, dl, TII.get(ADDInstr), StackReg) .addReg(StackReg, RegState::Kill) .addReg(TmpReg); } } } // Simply discard ADJCALLSTACKDOWN, ADJCALLSTACKUP instructions. MBB.erase(I); } bool PPCFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, const std::vector &CSI, const TargetRegisterInfo *TRI) const { // Currently, this function only handles SVR4 32- and 64-bit ABIs. // Return false otherwise to maintain pre-existing behavior. if (!Subtarget.isSVR4ABI()) return false; MachineFunction *MF = MBB.getParent(); const PPCInstrInfo &TII = *static_cast(MF->getTarget().getInstrInfo()); bool CR2Spilled = false; bool CR3Spilled = false; bool CR4Spilled = false; unsigned CSIIndex = 0; // Initialize insertion-point logic; we will be restoring in reverse // order of spill. MachineBasicBlock::iterator I = MI, BeforeI = I; bool AtStart = I == MBB.begin(); if (!AtStart) --BeforeI; for (unsigned i = 0, e = CSI.size(); i != e; ++i) { unsigned Reg = CSI[i].getReg(); // Only Darwin actually uses the VRSAVE register, but it can still appear // here if, for example, @llvm.eh.unwind.init() is used. If we're not on // Darwin, ignore it. if (Reg == PPC::VRSAVE && !Subtarget.isDarwinABI()) continue; if (Reg == PPC::CR2) { CR2Spilled = true; // The spill slot is associated only with CR2, which is the // first nonvolatile spilled. Save it here. CSIIndex = i; continue; } else if (Reg == PPC::CR3) { CR3Spilled = true; continue; } else if (Reg == PPC::CR4) { CR4Spilled = true; continue; } else { // When we first encounter a non-CR register after seeing at // least one CR register, restore all spilled CRs together. if ((CR2Spilled || CR3Spilled || CR4Spilled) && !(PPC::CR2 <= Reg && Reg <= PPC::CR4)) { bool is31 = needsFP(*MF); restoreCRs(Subtarget.isPPC64(), is31, CR2Spilled, CR3Spilled, CR4Spilled, MBB, I, CSI, CSIIndex); CR2Spilled = CR3Spilled = CR4Spilled = false; } // Default behavior for non-CR saves. const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg); TII.loadRegFromStackSlot(MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI); assert(I != MBB.begin() && "loadRegFromStackSlot didn't insert any code!"); } // Insert in reverse order. if (AtStart) I = MBB.begin(); else { I = BeforeI; ++I; } } // If we haven't yet spilled the CRs, do so now. if (CR2Spilled || CR3Spilled || CR4Spilled) { bool is31 = needsFP(*MF); restoreCRs(Subtarget.isPPC64(), is31, CR2Spilled, CR3Spilled, CR4Spilled, MBB, I, CSI, CSIIndex); } return true; }