//=====- PPCFrameLowering.cpp - PPC Frame Information -----------*- C++ -*-===// // // 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 "PPCInstrInfo.h" #include "PPCMachineFunctionInfo.h" #include "llvm/Function.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/Target/TargetOptions.h" using namespace llvm; // FIXME This disables some code that aligns the stack to a boundary bigger than // the default (16 bytes on Darwin) when there is a stack local of greater // alignment. This does not currently work, because the delta between old and // new stack pointers is added to offsets that reference incoming parameters // after the prolog is generated, and the code that does that doesn't handle a // variable delta. You don't want to do that anyway; a better approach is to // reserve another register that retains to the incoming stack pointer, and // reference parameters relative to that. #define ALIGN_STACK 0 /// VRRegNo - Map from a numbered VR register to its enum value. /// static const unsigned short 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 }; /// 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. 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().getDesc().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(); 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 = getPPCRegisterNumbering(I->first); if (VRRegNo[RegNo] == I->first) // If this really is a vector reg. UsedRegMask &= ~(1 << (31-RegNo)); // Doesn't need to be marked. } for (MachineRegisterInfo::liveout_iterator I = MF->getRegInfo().liveout_begin(), E = MF->getRegInfo().liveout_end(); I != E; ++I) { unsigned RegNo = getPPCRegisterNumbering(*I); if (VRRegNo[RegNo] == *I) // If this really is a vector reg. UsedRegMask &= ~(1 << (31-RegNo)); // Doesn't need to be marked. } // 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(); } /// determineFrameLayout - Determine the size of the frame and maximum call /// frame size. void PPCFrameLowering::determineFrameLayout(MachineFunction &MF) const { MachineFrameInfo *MFI = MF.getFrameInfo(); // Get the number of bytes to allocate from the FrameInfo unsigned FrameSize = MFI->getStackSize(); // Get the alignments provided by the target, and the maximum alignment // (if any) of the fixed frame objects. unsigned MaxAlign = MFI->getMaxAlignment(); unsigned TargetAlign = getStackAlignment(); unsigned AlignMask = TargetAlign - 1; // // 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). bool DisableRedZone = MF.getFunction()->hasFnAttr(Attribute::NoRedZone); // FIXME SVR4 The 32-bit SVR4 ABI has no red zone. if (!DisableRedZone && FrameSize <= 224 && // Fits in red zone. !MFI->hasVarSizedObjects() && // No dynamic alloca. !MFI->adjustsStack() && // No calls. (!ALIGN_STACK || MaxAlign <= TargetAlign)) { // No special alignment. // No need for frame MFI->setStackSize(0); return; } // 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 and 8 args. unsigned minCallFrameSize = getMinCallFrameSize(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. MFI->setMaxCallFrameSize(maxCallFrameSize); // Include call frame size in total. FrameSize += maxCallFrameSize; // Make sure the frame is aligned. FrameSize = (FrameSize + AlignMask) & ~AlignMask; // Update frame info. MFI->setStackSize(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()->hasFnAttr(Attribute::Naked)) return false; return DisableFramePointerElim(MF) || MFI->hasVarSizedObjects() || (GuaranteedTailCallOpt && MF.getInfo<PPCFunctionInfo>()->hasFastCall()); } 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.getTarget().getInstrInfo()); MachineModuleInfo &MMI = MF.getMMI(); DebugLoc dl; bool needsFrameMoves = MMI.hasDebugInfo() || MF.getFunction()->needsUnwindTableEntry(); // Prepare for frame info. MCSymbol *FrameLabel = 0; // Scan the prolog, looking for an UPDATE_VRSAVE instruction. If we find it, // process it. 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. // FIXME: determineFrameLayout() may change the frame size. This should be // moved upper, to some hook. determineFrameLayout(MF); unsigned FrameSize = MFI->getStackSize(); int NegFrameSize = -FrameSize; // Get processor type. bool isPPC64 = Subtarget.isPPC64(); // Get operating system bool isDarwinABI = Subtarget.isDarwinABI(); // Check if the link register (LR) must be saved. PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>(); bool MustSaveLR = FI->mustSaveLR(); // Do we have a frame pointer for this function? bool HasFP = hasFP(MF); int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI); int FPOffset = 0; if (HasFP) { if (Subtarget.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); } } if (isPPC64) { if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::MFLR8), PPC::X0); if (HasFP) BuildMI(MBB, MBBI, dl, TII.get(PPC::STD)) .addReg(PPC::X31) .addImm(FPOffset/4) .addReg(PPC::X1); if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::STD)) .addReg(PPC::X0) .addImm(LROffset / 4) .addReg(PPC::X1); } else { if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::MFLR), PPC::R0); if (HasFP) BuildMI(MBB, MBBI, dl, TII.get(PPC::STW)) .addReg(PPC::R31) .addImm(FPOffset) .addReg(PPC::R1); if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::STW)) .addReg(PPC::R0) .addImm(LROffset) .addReg(PPC::R1); } // Skip if a leaf routine. if (!FrameSize) return; // Get stack alignments. unsigned TargetAlign = getStackAlignment(); unsigned MaxAlign = MFI->getMaxAlignment(); // Adjust stack pointer: r1 += NegFrameSize. // If there is a preferred stack alignment, align R1 now if (!isPPC64) { // PPC32. if (ALIGN_STACK && MaxAlign > TargetAlign) { assert(isPowerOf2_32(MaxAlign) && isInt<16>(MaxAlign) && "Invalid alignment!"); assert(isInt<16>(NegFrameSize) && "Unhandled stack size and alignment!"); BuildMI(MBB, MBBI, dl, TII.get(PPC::RLWINM), PPC::R0) .addReg(PPC::R1) .addImm(0) .addImm(32 - Log2_32(MaxAlign)) .addImm(31); BuildMI(MBB, MBBI, dl, TII.get(PPC::SUBFIC) ,PPC::R0) .addReg(PPC::R0, RegState::Kill) .addImm(NegFrameSize); BuildMI(MBB, MBBI, dl, TII.get(PPC::STWUX)) .addReg(PPC::R1) .addReg(PPC::R1) .addReg(PPC::R0); } else if (isInt<16>(NegFrameSize)) { BuildMI(MBB, MBBI, dl, TII.get(PPC::STWU), PPC::R1) .addReg(PPC::R1) .addImm(NegFrameSize) .addReg(PPC::R1); } else { BuildMI(MBB, MBBI, dl, TII.get(PPC::LIS), PPC::R0) .addImm(NegFrameSize >> 16); BuildMI(MBB, MBBI, dl, TII.get(PPC::ORI), PPC::R0) .addReg(PPC::R0, RegState::Kill) .addImm(NegFrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, TII.get(PPC::STWUX)) .addReg(PPC::R1) .addReg(PPC::R1) .addReg(PPC::R0); } } else { // PPC64. if (ALIGN_STACK && MaxAlign > TargetAlign) { assert(isPowerOf2_32(MaxAlign) && isInt<16>(MaxAlign) && "Invalid alignment!"); assert(isInt<16>(NegFrameSize) && "Unhandled stack size and alignment!"); BuildMI(MBB, MBBI, dl, TII.get(PPC::RLDICL), PPC::X0) .addReg(PPC::X1) .addImm(0) .addImm(64 - Log2_32(MaxAlign)); BuildMI(MBB, MBBI, dl, TII.get(PPC::SUBFIC8), PPC::X0) .addReg(PPC::X0) .addImm(NegFrameSize); BuildMI(MBB, MBBI, dl, TII.get(PPC::STDUX)) .addReg(PPC::X1) .addReg(PPC::X1) .addReg(PPC::X0); } else if (isInt<16>(NegFrameSize)) { BuildMI(MBB, MBBI, dl, TII.get(PPC::STDU), PPC::X1) .addReg(PPC::X1) .addImm(NegFrameSize / 4) .addReg(PPC::X1); } else { BuildMI(MBB, MBBI, dl, TII.get(PPC::LIS8), PPC::X0) .addImm(NegFrameSize >> 16); BuildMI(MBB, MBBI, dl, TII.get(PPC::ORI8), PPC::X0) .addReg(PPC::X0, RegState::Kill) .addImm(NegFrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, TII.get(PPC::STDUX)) .addReg(PPC::X1) .addReg(PPC::X1) .addReg(PPC::X0); } } std::vector<MachineMove> &Moves = MMI.getFrameMoves(); // Add the "machine moves" for the instructions we generated above, but in // reverse order. if (needsFrameMoves) { // Mark effective beginning of when frame pointer becomes valid. FrameLabel = MMI.getContext().CreateTempSymbol(); BuildMI(MBB, MBBI, dl, TII.get(PPC::PROLOG_LABEL)).addSym(FrameLabel); // Show update of SP. if (NegFrameSize) { MachineLocation SPDst(MachineLocation::VirtualFP); MachineLocation SPSrc(MachineLocation::VirtualFP, NegFrameSize); Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc)); } else { MachineLocation SP(isPPC64 ? PPC::X31 : PPC::R31); Moves.push_back(MachineMove(FrameLabel, SP, SP)); } if (HasFP) { MachineLocation FPDst(MachineLocation::VirtualFP, FPOffset); MachineLocation FPSrc(isPPC64 ? PPC::X31 : PPC::R31); Moves.push_back(MachineMove(FrameLabel, FPDst, FPSrc)); } if (MustSaveLR) { MachineLocation LRDst(MachineLocation::VirtualFP, LROffset); MachineLocation LRSrc(isPPC64 ? PPC::LR8 : PPC::LR); Moves.push_back(MachineMove(FrameLabel, LRDst, LRSrc)); } } MCSymbol *ReadyLabel = 0; // If there is a frame pointer, copy R1 into R31 if (HasFP) { if (!isPPC64) { BuildMI(MBB, MBBI, dl, TII.get(PPC::OR), PPC::R31) .addReg(PPC::R1) .addReg(PPC::R1); } else { BuildMI(MBB, MBBI, dl, TII.get(PPC::OR8), PPC::X31) .addReg(PPC::X1) .addReg(PPC::X1); } if (needsFrameMoves) { ReadyLabel = MMI.getContext().CreateTempSymbol(); // Mark effective beginning of when frame pointer is ready. BuildMI(MBB, MBBI, dl, TII.get(PPC::PROLOG_LABEL)).addSym(ReadyLabel); MachineLocation FPDst(HasFP ? (isPPC64 ? PPC::X31 : PPC::R31) : (isPPC64 ? PPC::X1 : PPC::R1)); MachineLocation FPSrc(MachineLocation::VirtualFP); Moves.push_back(MachineMove(ReadyLabel, FPDst, FPSrc)); } } if (needsFrameMoves) { MCSymbol *Label = HasFP ? ReadyLabel : FrameLabel; // Add callee saved registers to move list. const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); for (unsigned I = 0, E = CSI.size(); I != E; ++I) { int Offset = MFI->getObjectOffset(CSI[I].getFrameIdx()); 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::CRBITRCRegisterClass->contains(Reg)) continue; MachineLocation CSDst(MachineLocation::VirtualFP, Offset); MachineLocation CSSrc(Reg); Moves.push_back(MachineMove(Label, CSDst, CSSrc)); } } } 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.getTarget().getInstrInfo()); 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 r1 const MachineFrameInfo *MFI = MF.getFrameInfo(); unsigned TargetAlign = getStackAlignment(); unsigned MaxAlign = MFI->getMaxAlignment(); // Get the number of bytes allocated from the FrameInfo. int FrameSize = MFI->getStackSize(); // Get processor type. bool isPPC64 = Subtarget.isPPC64(); // Get operating system bool isDarwinABI = Subtarget.isDarwinABI(); // Check if the link register (LR) has been saved. PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>(); bool MustSaveLR = FI->mustSaveLR(); // Do we have a frame pointer for this function? bool HasFP = hasFP(MF); int LROffset = PPCFrameLowering::getReturnSaveOffset(isPPC64, isDarwinABI); int FPOffset = 0; if (HasFP) { if (Subtarget.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); } } 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; } if (FrameSize) { // The loaded (or persistent) stack pointer value is offset by the 'stwu' // on entry to the function. Add this offset back now. if (!isPPC64) { // 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() && isInt<16>(FrameSize)) { assert(hasFP(MF) && "Expecting a valid the frame pointer."); BuildMI(MBB, MBBI, dl, TII.get(PPC::ADDI), PPC::R1) .addReg(PPC::R31).addImm(FrameSize); } else if(FI->hasFastCall()) { BuildMI(MBB, MBBI, dl, TII.get(PPC::LIS), PPC::R0) .addImm(FrameSize >> 16); BuildMI(MBB, MBBI, dl, TII.get(PPC::ORI), PPC::R0) .addReg(PPC::R0, RegState::Kill) .addImm(FrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, TII.get(PPC::ADD4)) .addReg(PPC::R1) .addReg(PPC::R31) .addReg(PPC::R0); } else if (isInt<16>(FrameSize) && (!ALIGN_STACK || TargetAlign >= MaxAlign) && !MFI->hasVarSizedObjects()) { BuildMI(MBB, MBBI, dl, TII.get(PPC::ADDI), PPC::R1) .addReg(PPC::R1).addImm(FrameSize); } else { BuildMI(MBB, MBBI, dl, TII.get(PPC::LWZ),PPC::R1) .addImm(0).addReg(PPC::R1); } } else { if (FI->hasFastCall() && isInt<16>(FrameSize)) { assert(hasFP(MF) && "Expecting a valid the frame pointer."); BuildMI(MBB, MBBI, dl, TII.get(PPC::ADDI8), PPC::X1) .addReg(PPC::X31).addImm(FrameSize); } else if(FI->hasFastCall()) { BuildMI(MBB, MBBI, dl, TII.get(PPC::LIS8), PPC::X0) .addImm(FrameSize >> 16); BuildMI(MBB, MBBI, dl, TII.get(PPC::ORI8), PPC::X0) .addReg(PPC::X0, RegState::Kill) .addImm(FrameSize & 0xFFFF); BuildMI(MBB, MBBI, dl, TII.get(PPC::ADD8)) .addReg(PPC::X1) .addReg(PPC::X31) .addReg(PPC::X0); } else if (isInt<16>(FrameSize) && TargetAlign >= MaxAlign && !MFI->hasVarSizedObjects()) { BuildMI(MBB, MBBI, dl, TII.get(PPC::ADDI8), PPC::X1) .addReg(PPC::X1).addImm(FrameSize); } else { BuildMI(MBB, MBBI, dl, TII.get(PPC::LD), PPC::X1) .addImm(0).addReg(PPC::X1); } } } if (isPPC64) { if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::LD), PPC::X0) .addImm(LROffset/4).addReg(PPC::X1); if (HasFP) BuildMI(MBB, MBBI, dl, TII.get(PPC::LD), PPC::X31) .addImm(FPOffset/4).addReg(PPC::X1); if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::MTLR8)).addReg(PPC::X0); } else { if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::LWZ), PPC::R0) .addImm(LROffset).addReg(PPC::R1); if (HasFP) BuildMI(MBB, MBBI, dl, TII.get(PPC::LWZ), PPC::R31) .addImm(FPOffset).addReg(PPC::R1); if (MustSaveLR) BuildMI(MBB, MBBI, dl, TII.get(PPC::MTLR)).addReg(PPC::R0); } // Callee pop calling convention. Pop parameter/linkage area. Used for tail // call optimization if (GuaranteedTailCallOpt && RetOpcode == PPC::BLR && MF.getFunction()->getCallingConv() == CallingConv::Fast) { PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>(); unsigned CallerAllocatedAmt = FI->getMinReservedArea(); unsigned StackReg = isPPC64 ? PPC::X1 : PPC::R1; unsigned FPReg = isPPC64 ? PPC::X31 : PPC::R31; unsigned TmpReg = isPPC64 ? PPC::X0 : PPC::R0; unsigned ADDIInstr = isPPC64 ? PPC::ADDI8 : PPC::ADDI; unsigned ADDInstr = isPPC64 ? PPC::ADD8 : PPC::ADD4; unsigned LISInstr = isPPC64 ? PPC::LIS8 : PPC::LIS; unsigned ORIInstr = isPPC64 ? PPC::ORI8 : PPC::ORI; if (CallerAllocatedAmt && isInt<16>(CallerAllocatedAmt)) { BuildMI(MBB, MBBI, dl, TII.get(ADDIInstr), StackReg) .addReg(StackReg).addImm(CallerAllocatedAmt); } else { BuildMI(MBB, MBBI, dl, TII.get(LISInstr), TmpReg) .addImm(CallerAllocatedAmt >> 16); BuildMI(MBB, MBBI, dl, TII.get(ORIInstr), TmpReg) .addReg(TmpReg, RegState::Kill) .addImm(CallerAllocatedAmt & 0xFFFF); BuildMI(MBB, MBBI, dl, TII.get(ADDInstr)) .addReg(StackReg) .addReg(FPReg) .addReg(TmpReg); } } 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()); } } static bool spillsCR(const MachineFunction &MF) { const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>(); return FuncInfo->isCRSpilled(); } /// 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 *RS) const { const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo(); // Save and clear the LR state. PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>(); unsigned LR = RegInfo->getRARegister(); FI->setMustSaveLR(MustSaveLR(MF, LR)); MF.getRegInfo().setPhysRegUnused(LR); // Save R31 if necessary int FPSI = FI->getFramePointerSaveIndex(); bool isPPC64 = Subtarget.isPPC64(); bool isDarwinABI = Subtarget.isDarwinABI(); 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); } // Reserve stack space to move the linkage area to in case of a tail call. int TCSPDelta = 0; if (GuaranteedTailCallOpt && (TCSPDelta = FI->getTailCallSPDelta()) < 0) { MFI->CreateFixedObject(-1 * TCSPDelta, TCSPDelta, true); } // 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. // FIXME: this doesn't actually check stack size, so is a bit pessimistic // FIXME: doesn't detect whether or not we need to spill vXX, which requires // r0 for now. if (RegInfo->requiresRegisterScavenging(MF)) // FIXME (64-bit): Enable. if (needsFP(MF) || spillsCR(MF)) { const TargetRegisterClass *GPRC = &PPC::GPRCRegClass; const TargetRegisterClass *G8RC = &PPC::G8RCRegClass; const TargetRegisterClass *RC = isPPC64 ? G8RC : GPRC; RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(), RC->getAlignment(), false)); } } void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF) const { // Early exit if not using the SVR4 ABI. if (!Subtarget.isSVR4ABI()) 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)) { 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 HasCRSaveArea = 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::GPRCRegisterClass->contains(Reg)) { HasGPSaveArea = true; GPRegs.push_back(CSI[i]); if (Reg < MinGPR) { MinGPR = Reg; } } else if (PPC::G8RCRegisterClass->contains(Reg)) { HasG8SaveArea = true; G8Regs.push_back(CSI[i]); if (Reg < MinG8R) { MinG8R = Reg; } } else if (PPC::F8RCRegisterClass->contains(Reg)) { HasFPSaveArea = true; FPRegs.push_back(CSI[i]); if (Reg < MinFPR) { MinFPR = Reg; } // FIXME SVR4: Disable CR save area for now. } else if (PPC::CRBITRCRegisterClass->contains(Reg) || PPC::CRRCRegisterClass->contains(Reg)) { // HasCRSaveArea = true; } else if (PPC::VRSAVERCRegisterClass->contains(Reg)) { HasVRSAVESaveArea = true; } else if (PPC::VRRCRegisterClass->contains(Reg)) { HasVRSaveArea = true; VRegs.push_back(CSI[i]); if (Reg < MinVR) { MinVR = Reg; } } else { llvm_unreachable("Unknown RegisterClass!"); } } PPCFunctionInfo *PFI = MF.getInfo<PPCFunctionInfo>(); int64_t LowerBound = 0; // Take into account stack space reserved for tail calls. int TCSPDelta = 0; if (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 - getPPCRegisterNumbering(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)); } // 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>(getPPCRegisterNumbering(MinGPR), getPPCRegisterNumbering(MinG8R)); if (Subtarget.isPPC64()) { LowerBound -= (31 - MinReg + 1) * 8; } else { LowerBound -= (31 - MinReg + 1) * 4; } } // The CR save area is below the general register save area. if (HasCRSaveArea) { // FIXME SVR4: Is it actually possible to have multiple elements in CSI // which have the CR/CRBIT register class? // 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 (PPC::CRBITRCRegisterClass->contains(Reg) || PPC::CRRCRegisterClass->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::VRSAVERCRegisterClass->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)); } } }