diff options
Diffstat (limited to 'contrib/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp | 1678 |
1 files changed, 1678 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/contrib/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp new file mode 100644 index 0000000..1b85047 --- /dev/null +++ b/contrib/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp @@ -0,0 +1,1678 @@ +//===-- 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->getSubtarget().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<PPCFunctionInfo>(); + return FuncInfo->isCRSpilled(); +} + +static bool spillsVRSAVE(const MachineFunction &MF) { + const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>(); + return FuncInfo->isVRSAVESpilled(); +} + +static bool hasSpills(const MachineFunction &MF) { + const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>(); + return FuncInfo->hasSpills(); +} + +static bool hasNonRISpills(const MachineFunction &MF) { + const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>(); + 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<const PPCRegisterInfo *>(MF.getSubtarget().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(), + Subtarget.isELFv2ABI()); + 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() || + MFI->hasStackMap() || MFI->hasPatchPoint() || + (MF.getTarget().Options.GuaranteedTailCallOpt && + MF.getInfo<PPCFunctionInfo>()->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<const PPCRegisterInfo *>(MF.getSubtarget().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<const PPCInstrInfo *>(MF.getSubtarget().getInstrInfo()); + const PPCRegisterInfo *RegInfo = + static_cast<const PPCRegisterInfo *>(MF.getSubtarget().getRegisterInfo()); + + MachineModuleInfo &MMI = MF.getMMI(); + const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo(); + DebugLoc dl; + bool needsCFI = 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(); + bool isELFv2ABI = Subtarget.isELFv2ABI(); + 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<PPCFunctionInfo>(); + bool MustSaveLR = FI->mustSaveLR(); + const SmallVectorImpl<unsigned> &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); + } + } + + int PBPOffset = 0; + if (FI->usesPICBase()) { + MachineFrameInfo *FFI = MF.getFrameInfo(); + int PBPIndex = FI->getPICBasePointerSaveIndex(); + assert(PBPIndex && "No PIC Base Pointer Save Slot!"); + PBPOffset = FFI->getObjectOffset(PBPIndex); + } + + // 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 + // FIXME: In the ELFv2 ABI, we are not required to save all CR fields. + // If only one or two CR fields are clobbered, it could be more + // efficient to use mfocrf to selectively save just those fields. + 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 (FI->usesPICBase()) + // FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe. + BuildMI(MBB, MBBI, dl, StoreInst) + .addReg(PPC::R30) + .addImm(PBPOffset) + .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 Call Frame Information for the instructions we generated above. + if (needsCFI) { + unsigned CFIIndex; + + if (HasBP) { + // Define CFA in terms of BP. Do this in preference to using FP/SP, + // because if the stack needed aligning then CFA won't be at a fixed + // offset from FP/SP. + unsigned Reg = MRI->getDwarfRegNum(BPReg, true); + CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaRegister(nullptr, Reg)); + } else { + // Adjust the definition of CFA to account for the change in SP. + assert(NegFrameSize); + CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, NegFrameSize)); + } + BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + if (HasFP) { + // Describe where FP was saved, at a fixed offset from CFA. + 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 (FI->usesPICBase()) { + // Describe where FP was saved, at a fixed offset from CFA. + unsigned Reg = MRI->getDwarfRegNum(PPC::R30, true); + CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createOffset(nullptr, Reg, PBPOffset)); + BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + } + + if (HasBP) { + // Describe where BP was saved, at a fixed offset from CFA. + 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) { + // Describe where LR was saved, at a fixed offset from CFA. + 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 (!HasBP && needsCFI) { + // Change the definition of CFA from SP+offset to FP+offset, because SP + // will change at every alloca. + 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 (needsCFI) { + // Describe where callee saved registers were saved, at fixed offsets from + // CFA. + const std::vector<CalleeSavedInfo> &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)) { + // In the ELFv1 ABI, only CR2 is noted in CFI and stands in for + // the whole CR word. In the ELFv2 ABI, every CR that was + // actually saved gets its own CFI record. + unsigned CRReg = isELFv2ABI? Reg : (unsigned) PPC::CR2; + unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( + nullptr, MRI->getDwarfRegNum(CRReg, 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<const PPCInstrInfo *>(MF.getSubtarget().getInstrInfo()); + const PPCRegisterInfo *RegInfo = + static_cast<const PPCRegisterInfo *>(MF.getSubtarget().getRegisterInfo()); + + unsigned RetOpcode = MBBI->getOpcode(); + DebugLoc dl; + + assert((RetOpcode == PPC::BLR || + RetOpcode == PPC::BLR8 || + 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<PPCFunctionInfo>(); + bool MustSaveLR = FI->mustSaveLR(); + const SmallVectorImpl<unsigned> &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); + } + } + + int PBPOffset = 0; + if (FI->usesPICBase()) { + MachineFrameInfo *FFI = MF.getFrameInfo(); + int PBPIndex = FI->getPICBasePointerSaveIndex(); + assert(PBPIndex && "No PIC Base Pointer Save Slot!"); + PBPOffset = FFI->getObjectOffset(PBPIndex); + } + + 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 (FI->usesPICBase()) + // FIXME: On PPC32 SVR4, we must not spill before claiming the stackframe. + BuildMI(MBB, MBBI, dl, LoadInst) + .addReg(PPC::R30) + .addImm(PBPOffset) + .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 || RetOpcode == PPC::BLR8) && + MF.getFunction()->getCallingConv() == CallingConv::Fast) { + PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>(); + 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<PPCFunctionInfo>(); + + // 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<const PPCRegisterInfo *>(MF.getSubtarget().getRegisterInfo()); + + // Save and clear the LR state. + PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>(); + 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 for the PIC Base register (R30). + // Only used in SVR4 32-bit. + if (FI->usesPICBase()) { + int PBPSI = FI->getPICBasePointerSaveIndex(); + PBPSI = MFI->CreateFixedObject(4, -8, true); + FI->setPICBasePointerSaveIndex(PBPSI); + } + + // 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<CalleeSavedInfo> &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<CalleeSavedInfo, 18> GPRegs; + SmallVector<CalleeSavedInfo, 18> G8Regs; + SmallVector<CalleeSavedInfo, 18> FPRegs; + SmallVector<CalleeSavedInfo, 18> 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<PPCFunctionInfo>(); + const TargetRegisterInfo *TRI = MF.getSubtarget().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)); + } + + if (PFI->usesPICBase()) { + HasGPSaveArea = true; + + int FI = PFI->getPICBasePointerSaveIndex(); + assert(FI && "No PIC Base Pointer Save Slot!"); + + FFI->setObjectOffset(FI, LowerBound + FFI->getObjectOffset(FI)); + } + + const PPCRegisterInfo *RegInfo = + static_cast<const PPCRegisterInfo *>(MF.getSubtarget().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<unsigned>(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<CalleeSavedInfo> &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<const PPCInstrInfo *>(MF->getSubtarget().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<PPCFunctionInfo>(); + 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<CalleeSavedInfo> &CSI, unsigned CSIIndex) { + + MachineFunction *MF = MBB.getParent(); + const PPCInstrInfo &TII = + *static_cast<const PPCInstrInfo *>(MF->getSubtarget().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<const PPCInstrInfo *>(MF.getSubtarget().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<CalleeSavedInfo> &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<const PPCInstrInfo *>(MF->getSubtarget().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; +} |
