X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTarget%2FARM%2FARMFrameLowering.cpp;h=74f686507df5fb8257f1bf41abad9e77b37b271c;hb=12af22e8cc217827cf4f118b0f5e4ebbda9925ae;hp=916417882bae4775e099ee84429396225aed0d47;hpb=e228078ca6de1c5316ec53a370568ea5d824f8e5;p=oota-llvm.git diff --git a/lib/Target/ARM/ARMFrameLowering.cpp b/lib/Target/ARM/ARMFrameLowering.cpp index 916417882ba..74f686507df 100644 --- a/lib/Target/ARM/ARMFrameLowering.cpp +++ b/lib/Target/ARM/ARMFrameLowering.cpp @@ -14,6 +14,7 @@ #include "ARMFrameLowering.h" #include "ARMBaseInstrInfo.h" #include "ARMBaseRegisterInfo.h" +#include "ARMConstantPoolValue.h" #include "ARMMachineFunctionInfo.h" #include "MCTargetDesc/ARMAddressingModes.h" #include "llvm/CodeGen/MachineFrameInfo.h" @@ -38,11 +39,15 @@ static MachineBasicBlock::iterator skipAlignedDPRCS2Spills(MachineBasicBlock::iterator MI, unsigned NumAlignedDPRCS2Regs); +ARMFrameLowering::ARMFrameLowering(const ARMSubtarget &sti) + : TargetFrameLowering(StackGrowsDown, sti.getStackAlignment(), 0, 4), + STI(sti) {} + /// hasFP - 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 ARMFrameLowering::hasFP(const MachineFunction &MF) const { - const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo(); + const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo(); // iOS requires FP not to be clobbered for backtracing purpose. if (STI.isTargetIOS()) @@ -86,7 +91,7 @@ ARMFrameLowering::canSimplifyCallFramePseudos(const MachineFunction &MF) const { static bool isCSRestore(MachineInstr *MI, const ARMBaseInstrInfo &TII, - const uint16_t *CSRegs) { + const MCPhysReg *CSRegs) { // Integer spill area is handled with "pop". if (isPopOpcode(MI->getOpcode())) { // The first two operands are predicates. The last two are @@ -141,6 +146,14 @@ static int sizeOfSPAdjustment(const MachineInstr *MI) { return count; } +static bool WindowsRequiresStackProbe(const MachineFunction &MF, + size_t StackSizeInBytes) { + const MachineFrameInfo *MFI = MF.getFrameInfo(); + if (MFI->getStackProtectorIndex() > 0) + return StackSizeInBytes >= 4080; + return StackSizeInBytes >= 4096; +} + void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { MachineBasicBlock &MBB = MF.front(); MachineBasicBlock::iterator MBBI = MBB.begin(); @@ -148,15 +161,17 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { ARMFunctionInfo *AFI = MF.getInfo(); MachineModuleInfo &MMI = MF.getMMI(); MCContext &Context = MMI.getContext(); + const TargetMachine &TM = MF.getTarget(); const MCRegisterInfo *MRI = Context.getRegisterInfo(); - const ARMBaseRegisterInfo *RegInfo = - static_cast(MF.getTarget().getRegisterInfo()); - const ARMBaseInstrInfo &TII = - *static_cast(MF.getTarget().getInstrInfo()); + const ARMBaseRegisterInfo *RegInfo = static_cast( + TM.getSubtargetImpl()->getRegisterInfo()); + const ARMBaseInstrInfo &TII = *static_cast( + TM.getSubtargetImpl()->getInstrInfo()); assert(!AFI->isThumb1OnlyFunction() && "This emitPrologue does not support Thumb1!"); bool isARM = !AFI->isThumbFunction(); - unsigned Align = MF.getTarget().getFrameLowering()->getStackAlignment(); + unsigned Align = + TM.getSubtargetImpl()->getFrameLowering()->getStackAlignment(); unsigned ArgRegsSaveSize = AFI->getArgRegsSaveSize(Align); unsigned NumBytes = MFI->getStackSize(); const std::vector &CSI = MFI->getCalleeSavedInfo(); @@ -175,28 +190,27 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { if (MF.getFunction()->getCallingConv() == CallingConv::GHC) return; - // Allocate the vararg register save area. This is not counted in NumBytes. + // Allocate the vararg register save area. if (ArgRegsSaveSize) { emitSPUpdate(isARM, MBB, MBBI, dl, TII, -ArgRegsSaveSize, MachineInstr::FrameSetup); - MCSymbol *SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); CFAOffset -= ArgRegsSaveSize; - MMI.addFrameInst( - MCCFIInstruction::createDefCfaOffset(SPLabel, CFAOffset)); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); + BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } - if (!AFI->hasStackFrame()) { - if (NumBytes != 0) { - emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes, + if (!AFI->hasStackFrame() && + (!STI.isTargetWindows() || !WindowsRequiresStackProbe(MF, NumBytes))) { + if (NumBytes - ArgRegsSaveSize != 0) { + emitSPUpdate(isARM, MBB, MBBI, dl, TII, -(NumBytes - ArgRegsSaveSize), MachineInstr::FrameSetup); - MCSymbol *SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); - CFAOffset -= NumBytes; - MMI.addFrameInst(MCCFIInstruction::createDefCfaOffset(SPLabel, - CFAOffset)); + CFAOffset -= NumBytes - ArgRegsSaveSize; + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); + BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } return; } @@ -211,7 +225,7 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { case ARM::R10: case ARM::R11: case ARM::R12: - if (STI.isTargetMachO()) { + if (STI.isTargetDarwin()) { GPRCS2Size += 4; break; } @@ -246,12 +260,14 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { // Determine starting offsets of spill areas. bool HasFP = hasFP(MF); - unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize); + unsigned DPRCSOffset = NumBytes - (ArgRegsSaveSize + GPRCS1Size + + GPRCS2Size + DPRCSSize); unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize; unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size; int FramePtrOffsetInPush = 0; if (HasFP) { - FramePtrOffsetInPush = MFI->getObjectOffset(FramePtrSpillFI) + GPRCS1Size; + FramePtrOffsetInPush = MFI->getObjectOffset(FramePtrSpillFI) + + GPRCS1Size + ArgRegsSaveSize; AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes); } @@ -283,6 +299,51 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { } else NumBytes = DPRCSOffset; + if (STI.isTargetWindows() && WindowsRequiresStackProbe(MF, NumBytes)) { + uint32_t NumWords = NumBytes >> 2; + + if (NumWords < 65536) + AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi16), ARM::R4) + .addImm(NumWords) + .setMIFlags(MachineInstr::FrameSetup)); + else + BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi32imm), ARM::R4) + .addImm(NumWords) + .setMIFlags(MachineInstr::FrameSetup); + + switch (TM.getCodeModel()) { + case CodeModel::Small: + case CodeModel::Medium: + case CodeModel::Default: + case CodeModel::Kernel: + BuildMI(MBB, MBBI, dl, TII.get(ARM::tBL)) + .addImm((unsigned)ARMCC::AL).addReg(0) + .addExternalSymbol("__chkstk") + .addReg(ARM::R4, RegState::Implicit) + .setMIFlags(MachineInstr::FrameSetup); + break; + case CodeModel::Large: + case CodeModel::JITDefault: + BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi32imm), ARM::R12) + .addExternalSymbol("__chkstk") + .setMIFlags(MachineInstr::FrameSetup); + + BuildMI(MBB, MBBI, dl, TII.get(ARM::tBLXr)) + .addImm((unsigned)ARMCC::AL).addReg(0) + .addReg(ARM::R12, RegState::Kill) + .addReg(ARM::R4, RegState::Implicit) + .setMIFlags(MachineInstr::FrameSetup); + break; + } + + AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::t2SUBrr), + ARM::SP) + .addReg(ARM::SP, RegState::Define) + .addReg(ARM::R4, RegState::Kill) + .setMIFlags(MachineInstr::FrameSetup))); + NumBytes = 0; + } + unsigned adjustedGPRCS1Size = GPRCS1Size; if (NumBytes) { // Adjust SP after all the callee-save spills. @@ -309,23 +370,22 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { } if (adjustedGPRCS1Size > 0) { - MCSymbol *SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, ++GPRCS1Push, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); CFAOffset -= adjustedGPRCS1Size; - MMI.addFrameInst( - MCCFIInstruction::createDefCfaOffset(SPLabel, CFAOffset)); - for (std::vector::const_iterator I = CSI.begin(), - E = CSI.end(); I != E; ++I) { - unsigned Reg = I->getReg(); - int FI = I->getFrameIdx(); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); + MachineBasicBlock::iterator Pos = ++GPRCS1Push; + BuildMI(MBB, Pos, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + for (const auto &Entry : CSI) { + unsigned Reg = Entry.getReg(); + int FI = Entry.getFrameIdx(); switch (Reg) { case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: case ARM::R12: - if (STI.isTargetMachO()) + if (STI.isTargetDarwin()) break; // fallthrough case ARM::R0: @@ -337,9 +397,10 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { case ARM::R6: case ARM::R7: case ARM::LR: - MMI.addFrameInst(MCCFIInstruction::createOffset(SPLabel, - MRI->getDwarfRegNum(Reg, true), - MFI->getObjectOffset(FI) - ArgRegsSaveSize)); + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( + nullptr, MRI->getDwarfRegNum(Reg, true), MFI->getObjectOffset(FI))); + BuildMI(MBB, Pos, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); break; } } @@ -355,44 +416,47 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { emitRegPlusImmediate(!AFI->isThumbFunction(), MBB, GPRCS1Push, dl, TII, FramePtr, ARM::SP, FramePtrOffsetInPush, MachineInstr::FrameSetup); - MCSymbol *SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, GPRCS1Push, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); if (FramePtrOffsetInPush) { CFAOffset += FramePtrOffsetInPush; - MMI.addFrameInst( - MCCFIInstruction::createDefCfa(SPLabel, - MRI->getDwarfRegNum(FramePtr, true), CFAOffset)); - } else - MMI.addFrameInst( - MCCFIInstruction::createDefCfaRegister(SPLabel, - MRI->getDwarfRegNum(FramePtr, true))); + unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfa( + nullptr, MRI->getDwarfRegNum(FramePtr, true), CFAOffset)); + BuildMI(MBB, GPRCS1Push, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + } else { + unsigned CFIIndex = + MMI.addFrameInst(MCCFIInstruction::createDefCfaRegister( + nullptr, MRI->getDwarfRegNum(FramePtr, true))); + BuildMI(MBB, GPRCS1Push, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + } } if (GPRCS2Size > 0) { - MCSymbol *SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, ++GPRCS2Push, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); + MachineBasicBlock::iterator Pos = ++GPRCS2Push; if (!HasFP) { CFAOffset -= GPRCS2Size; - MMI.addFrameInst( - MCCFIInstruction::createDefCfaOffset(SPLabel, CFAOffset)); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); + BuildMI(MBB, Pos, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } - for (std::vector::const_iterator I = CSI.begin(), - E = CSI.end(); I != E; ++I) { - unsigned Reg = I->getReg(); - int FI = I->getFrameIdx(); + for (const auto &Entry : CSI) { + unsigned Reg = Entry.getReg(); + int FI = Entry.getFrameIdx(); switch (Reg) { case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11: case ARM::R12: - if (STI.isTargetMachO()) { + if (STI.isTargetDarwin()) { unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true); - unsigned Offset = MFI->getObjectOffset(FI) - ArgRegsSaveSize; - MMI.addFrameInst( - MCCFIInstruction::createOffset(SPLabel, DwarfReg, Offset)); + unsigned Offset = MFI->getObjectOffset(FI); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createOffset(nullptr, DwarfReg, Offset)); + BuildMI(MBB, Pos, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } break; } @@ -402,46 +466,39 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const { if (DPRCSSize > 0) { // Since vpush register list cannot have gaps, there may be multiple vpush // instructions in the prologue. - MCSymbol *SPLabel = NULL; do { MachineBasicBlock::iterator Push = DPRCSPush++; if (!HasFP) { - SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, DPRCSPush, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); - CFAOffset -= sizeOfSPAdjustment(Push);; - MMI.addFrameInst( - MCCFIInstruction::createDefCfaOffset(SPLabel, CFAOffset)); + CFAOffset -= sizeOfSPAdjustment(Push); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); + BuildMI(MBB, DPRCSPush, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } } while (DPRCSPush->getOpcode() == ARM::VSTMDDB_UPD); - if (!SPLabel) { - SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, DPRCSPush, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); - } - for (std::vector::const_iterator I = CSI.begin(), - E = CSI.end(); I != E; ++I) { - unsigned Reg = I->getReg(); - int FI = I->getFrameIdx(); + for (const auto &Entry : CSI) { + unsigned Reg = Entry.getReg(); + int FI = Entry.getFrameIdx(); if ((Reg >= ARM::D0 && Reg <= ARM::D31) && (Reg < ARM::D8 || Reg >= ARM::D8 + AFI->getNumAlignedDPRCS2Regs())) { unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true); unsigned Offset = MFI->getObjectOffset(FI); - MMI.addFrameInst(MCCFIInstruction::createOffset(SPLabel, DwarfReg, - Offset)); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createOffset(nullptr, DwarfReg, Offset)); + BuildMI(MBB, DPRCSPush, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } } } if (NumBytes) { if (!HasFP) { - MCSymbol *SPLabel = Context.CreateTempSymbol(); - BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::PROLOG_LABEL)) - .addSym(SPLabel); CFAOffset -= NumBytes; - MMI.addFrameInst( - MCCFIInstruction::createDefCfaOffset(SPLabel, CFAOffset)); + unsigned CFIIndex = MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(nullptr, CFAOffset)); + BuildMI(MBB, MBBI, dl, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); } } @@ -518,14 +575,17 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF, DebugLoc dl = MBBI->getDebugLoc(); MachineFrameInfo *MFI = MF.getFrameInfo(); ARMFunctionInfo *AFI = MF.getInfo(); - const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo(); + const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo(); const ARMBaseInstrInfo &TII = - *static_cast(MF.getTarget().getInstrInfo()); + *static_cast(MF.getSubtarget().getInstrInfo()); assert(!AFI->isThumb1OnlyFunction() && "This emitEpilogue does not support Thumb1!"); bool isARM = !AFI->isThumbFunction(); - unsigned Align = MF.getTarget().getFrameLowering()->getStackAlignment(); + unsigned Align = MF.getTarget() + .getSubtargetImpl() + ->getFrameLowering() + ->getStackAlignment(); unsigned ArgRegsSaveSize = AFI->getArgRegsSaveSize(Align); int NumBytes = (int)MFI->getStackSize(); unsigned FramePtr = RegInfo->getFrameRegister(MF); @@ -536,11 +596,11 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF, return; if (!AFI->hasStackFrame()) { - if (NumBytes != 0) - emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes); + if (NumBytes - ArgRegsSaveSize != 0) + emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes - ArgRegsSaveSize); } else { // Unwind MBBI to point to first LDR / VLDRD. - const uint16_t *CSRegs = RegInfo->getCalleeSavedRegs(&MF); + const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&MF); if (MBBI != MBB.begin()) { do { --MBBI; @@ -550,7 +610,8 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF, } // Move SP to start of FP callee save spill area. - NumBytes -= (AFI->getGPRCalleeSavedArea1Size() + + NumBytes -= (ArgRegsSaveSize + + AFI->getGPRCalleeSavedArea1Size() + AFI->getGPRCalleeSavedArea2Size() + AFI->getDPRCalleeSavedAreaSize()); @@ -632,7 +693,7 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF, addReg(JumpTarget.getReg(), RegState::Kill); } - MachineInstr *NewMI = prior(MBBI); + MachineInstr *NewMI = std::prev(MBBI); for (unsigned i = 1, e = MBBI->getNumOperands(); i != e; ++i) NewMI->addOperand(MBBI->getOperand(i)); @@ -660,8 +721,8 @@ ARMFrameLowering::ResolveFrameIndexReference(const MachineFunction &MF, int FI, unsigned &FrameReg, int SPAdj) const { const MachineFrameInfo *MFI = MF.getFrameInfo(); - const ARMBaseRegisterInfo *RegInfo = - static_cast(MF.getTarget().getRegisterInfo()); + const ARMBaseRegisterInfo *RegInfo = static_cast( + MF.getSubtarget().getRegisterInfo()); const ARMFunctionInfo *AFI = MF.getInfo(); int Offset = MFI->getObjectOffset(FI) + MFI->getStackSize(); int FPOffset = Offset - AFI->getFramePtrSpillOffset(); @@ -746,7 +807,7 @@ void ARMFrameLowering::emitPushInst(MachineBasicBlock &MBB, unsigned NumAlignedDPRCS2Regs, unsigned MIFlags) const { MachineFunction &MF = *MBB.getParent(); - const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); + const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); DebugLoc DL; if (MI != MBB.end()) DL = MI->getDebugLoc(); @@ -757,7 +818,7 @@ void ARMFrameLowering::emitPushInst(MachineBasicBlock &MBB, unsigned LastReg = 0; for (; i != 0; --i) { unsigned Reg = CSI[i-1].getReg(); - if (!(Func)(Reg, STI.isTargetMachO())) continue; + if (!(Func)(Reg, STI.isTargetDarwin())) continue; // D-registers in the aligned area DPRCS2 are NOT spilled here. if (Reg >= ARM::D8 && Reg < ARM::D8 + NumAlignedDPRCS2Regs) @@ -803,6 +864,11 @@ void ARMFrameLowering::emitPushInst(MachineBasicBlock &MBB, AddDefaultPred(MIB); } Regs.clear(); + + // Put any subsequent vpush instructions before this one: they will refer to + // higher register numbers so need to be pushed first in order to preserve + // monotonicity. + --MI; } } @@ -814,7 +880,7 @@ void ARMFrameLowering::emitPopInst(MachineBasicBlock &MBB, bool(*Func)(unsigned, bool), unsigned NumAlignedDPRCS2Regs) const { MachineFunction &MF = *MBB.getParent(); - const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); + const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); ARMFunctionInfo *AFI = MF.getInfo(); DebugLoc DL = MI->getDebugLoc(); unsigned RetOpcode = MI->getOpcode(); @@ -830,7 +896,7 @@ void ARMFrameLowering::emitPopInst(MachineBasicBlock &MBB, bool DeleteRet = false; for (; i != 0; --i) { unsigned Reg = CSI[i-1].getReg(); - if (!(Func)(Reg, STI.isTargetMachO())) continue; + if (!(Func)(Reg, STI.isTargetDarwin())) continue; // The aligned reloads from area DPRCS2 are not inserted here. if (Reg >= ARM::D8 && Reg < ARM::D8 + NumAlignedDPRCS2Regs) @@ -886,6 +952,10 @@ void ARMFrameLowering::emitPopInst(MachineBasicBlock &MBB, AddDefaultPred(MIB); } Regs.clear(); + + // Put any subsequent vpop instructions after this one: they will refer to + // higher register numbers so need to be popped afterwards. + ++MI; } } @@ -900,7 +970,7 @@ static void emitAlignedDPRCS2Spills(MachineBasicBlock &MBB, MachineFunction &MF = *MBB.getParent(); ARMFunctionInfo *AFI = MF.getInfo(); DebugLoc DL = MI->getDebugLoc(); - const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); + const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); MachineFrameInfo &MFI = *MF.getFrameInfo(); // Mark the D-register spill slots as properly aligned. Since MFI computes @@ -1017,7 +1087,7 @@ static void emitAlignedDPRCS2Spills(MachineBasicBlock &MBB, } // The last spill instruction inserted should kill the scratch register r4. - llvm::prior(MI)->addRegisterKilled(ARM::R4, TRI); + std::prev(MI)->addRegisterKilled(ARM::R4, TRI); } /// Skip past the code inserted by emitAlignedDPRCS2Spills, and return an @@ -1059,7 +1129,7 @@ static void emitAlignedDPRCS2Restores(MachineBasicBlock &MBB, MachineFunction &MF = *MBB.getParent(); ARMFunctionInfo *AFI = MF.getInfo(); DebugLoc DL = MI->getDebugLoc(); - const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo(); + const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); // Find the frame index assigned to d8. int D8SpillFI = 0; @@ -1127,7 +1197,7 @@ static void emitAlignedDPRCS2Restores(MachineBasicBlock &MBB, .addReg(ARM::R4).addImm(2*(NextReg-R4BaseReg))); // Last store kills r4. - llvm::prior(MI)->addRegisterKilled(ARM::R4, TRI); + std::prev(MI)->addRegisterKilled(ARM::R4, TRI); } bool ARMFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB, @@ -1195,12 +1265,9 @@ bool ARMFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB, static unsigned GetFunctionSizeInBytes(const MachineFunction &MF, const ARMBaseInstrInfo &TII) { unsigned FnSize = 0; - for (MachineFunction::const_iterator MBBI = MF.begin(), E = MF.end(); - MBBI != E; ++MBBI) { - const MachineBasicBlock &MBB = *MBBI; - for (MachineBasicBlock::const_iterator I = MBB.begin(),E = MBB.end(); - I != E; ++I) - FnSize += TII.GetInstSizeInBytes(I); + for (auto &MBB : MF) { + for (auto &MI : MBB) + FnSize += TII.GetInstSizeInBytes(&MI); } return FnSize; } @@ -1213,21 +1280,21 @@ static unsigned estimateRSStackSizeLimit(MachineFunction &MF, const TargetFrameLowering *TFI) { const ARMFunctionInfo *AFI = MF.getInfo(); unsigned Limit = (1 << 12) - 1; - for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) { - for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); - I != E; ++I) { - for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { - if (!I->getOperand(i).isFI()) continue; + for (auto &MBB : MF) { + for (auto &MI : MBB) { + for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) { + if (!MI.getOperand(i).isFI()) + continue; // When using ADDri to get the address of a stack object, 255 is the // largest offset guaranteed to fit in the immediate offset. - if (I->getOpcode() == ARM::ADDri) { + if (MI.getOpcode() == ARM::ADDri) { Limit = std::min(Limit, (1U << 8) - 1); break; } // Otherwise check the addressing mode. - switch (I->getDesc().TSFlags & ARMII::AddrModeMask) { + switch (MI.getDesc().TSFlags & ARMII::AddrModeMask) { case ARMII::AddrMode3: case ARMII::AddrModeT2_i8: Limit = std::min(Limit, (1U << 8) - 1); @@ -1277,12 +1344,15 @@ static void checkNumAlignedDPRCS2Regs(MachineFunction &MF) { return; // Don't bother if the default stack alignment is sufficiently high. - if (MF.getTarget().getFrameLowering()->getStackAlignment() >= 8) + if (MF.getTarget() + .getSubtargetImpl() + ->getFrameLowering() + ->getStackAlignment() >= 8) return; // Aligned spills require stack realignment. - const ARMBaseRegisterInfo *RegInfo = - static_cast(MF.getTarget().getRegisterInfo()); + const ARMBaseRegisterInfo *RegInfo = static_cast( + MF.getSubtarget().getRegisterInfo()); if (!RegInfo->canRealignStack(MF)) return; @@ -1321,10 +1391,10 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, unsigned NumGPRSpills = 0; SmallVector UnspilledCS1GPRs; SmallVector UnspilledCS2GPRs; - const ARMBaseRegisterInfo *RegInfo = - static_cast(MF.getTarget().getRegisterInfo()); + const ARMBaseRegisterInfo *RegInfo = static_cast( + MF.getSubtarget().getRegisterInfo()); const ARMBaseInstrInfo &TII = - *static_cast(MF.getTarget().getInstrInfo()); + *static_cast(MF.getSubtarget().getInstrInfo()); ARMFunctionInfo *AFI = MF.getInfo(); MachineFrameInfo *MFI = MF.getFrameInfo(); MachineRegisterInfo &MRI = MF.getRegInfo(); @@ -1364,7 +1434,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, // Don't spill FP if the frame can be eliminated. This is determined // by scanning the callee-save registers to see if any is used. - const uint16_t *CSRegs = RegInfo->getCalleeSavedRegs(&MF); + const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&MF); for (unsigned i = 0; CSRegs[i]; ++i) { unsigned Reg = CSRegs[i]; bool Spilled = false; @@ -1379,7 +1449,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, if (Spilled) { NumGPRSpills++; - if (!STI.isTargetMachO()) { + if (!STI.isTargetDarwin()) { if (Reg == ARM::LR) LRSpilled = true; CS1Spilled = true; @@ -1401,7 +1471,7 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, break; } } else { - if (!STI.isTargetMachO()) { + if (!STI.isTargetDarwin()) { UnspilledCS1GPRs.push_back(Reg); continue; } @@ -1476,6 +1546,10 @@ ARMFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, if (hasFP(MF)) { MRI.setPhysRegUsed(FramePtr); + auto FPPos = std::find(UnspilledCS1GPRs.begin(), UnspilledCS1GPRs.end(), + FramePtr); + if (FPPos != UnspilledCS1GPRs.end()) + UnspilledCS1GPRs.erase(FPPos); NumGPRSpills++; } @@ -1561,7 +1635,7 @@ void ARMFrameLowering:: eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const { const ARMBaseInstrInfo &TII = - *static_cast(MF.getTarget().getInstrInfo()); + *static_cast(MF.getSubtarget().getInstrInfo()); if (!hasReservedCallFrame(MF)) { // If we have alloca, convert as follows: // ADJCALLSTACKDOWN -> sub, sp, sp, amount @@ -1603,3 +1677,370 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MBB.erase(I); } +/// Get the minimum constant for ARM that is greater than or equal to the +/// argument. In ARM, constants can have any value that can be produced by +/// rotating an 8-bit value to the right by an even number of bits within a +/// 32-bit word. +static uint32_t alignToARMConstant(uint32_t Value) { + unsigned Shifted = 0; + + if (Value == 0) + return 0; + + while (!(Value & 0xC0000000)) { + Value = Value << 2; + Shifted += 2; + } + + bool Carry = (Value & 0x00FFFFFF); + Value = ((Value & 0xFF000000) >> 24) + Carry; + + if (Value & 0x0000100) + Value = Value & 0x000001FC; + + if (Shifted > 24) + Value = Value >> (Shifted - 24); + else + Value = Value << (24 - Shifted); + + return Value; +} + +// The stack limit in the TCB is set to this many bytes above the actual +// stack limit. +static const uint64_t kSplitStackAvailable = 256; + +// Adjust the function prologue to enable split stacks. This currently only +// supports android and linux. +// +// The ABI of the segmented stack prologue is a little arbitrarily chosen, but +// must be well defined in order to allow for consistent implementations of the +// __morestack helper function. The ABI is also not a normal ABI in that it +// doesn't follow the normal calling conventions because this allows the +// prologue of each function to be optimized further. +// +// Currently, the ABI looks like (when calling __morestack) +// +// * r4 holds the minimum stack size requested for this function call +// * r5 holds the stack size of the arguments to the function +// * the beginning of the function is 3 instructions after the call to +// __morestack +// +// Implementations of __morestack should use r4 to allocate a new stack, r5 to +// place the arguments on to the new stack, and the 3-instruction knowledge to +// jump directly to the body of the function when working on the new stack. +// +// An old (and possibly no longer compatible) implementation of __morestack for +// ARM can be found at [1]. +// +// [1] - https://github.com/mozilla/rust/blob/86efd9/src/rt/arch/arm/morestack.S +void ARMFrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { + unsigned Opcode; + unsigned CFIIndex; + const ARMSubtarget *ST = &MF.getTarget().getSubtarget(); + bool Thumb = ST->isThumb(); + + // Sadly, this currently doesn't support varargs, platforms other than + // android/linux. Note that thumb1/thumb2 are support for android/linux. + if (MF.getFunction()->isVarArg()) + report_fatal_error("Segmented stacks do not support vararg functions."); + if (!ST->isTargetAndroid() && !ST->isTargetLinux()) + report_fatal_error("Segmented stacks not supported on this platform."); + + MachineBasicBlock &prologueMBB = MF.front(); + MachineFrameInfo *MFI = MF.getFrameInfo(); + MachineModuleInfo &MMI = MF.getMMI(); + MCContext &Context = MMI.getContext(); + const MCRegisterInfo *MRI = Context.getRegisterInfo(); + const ARMBaseInstrInfo &TII = + *static_cast(MF.getSubtarget().getInstrInfo()); + ARMFunctionInfo *ARMFI = MF.getInfo(); + DebugLoc DL; + + uint64_t StackSize = MFI->getStackSize(); + + // Do not generate a prologue for functions with a stack of size zero + if (StackSize == 0) + return; + + // Use R4 and R5 as scratch registers. + // We save R4 and R5 before use and restore them before leaving the function. + unsigned ScratchReg0 = ARM::R4; + unsigned ScratchReg1 = ARM::R5; + uint64_t AlignedStackSize; + + MachineBasicBlock *PrevStackMBB = MF.CreateMachineBasicBlock(); + MachineBasicBlock *PostStackMBB = MF.CreateMachineBasicBlock(); + MachineBasicBlock *AllocMBB = MF.CreateMachineBasicBlock(); + MachineBasicBlock *GetMBB = MF.CreateMachineBasicBlock(); + MachineBasicBlock *McrMBB = MF.CreateMachineBasicBlock(); + + for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(), + e = prologueMBB.livein_end(); + i != e; ++i) { + AllocMBB->addLiveIn(*i); + GetMBB->addLiveIn(*i); + McrMBB->addLiveIn(*i); + PrevStackMBB->addLiveIn(*i); + PostStackMBB->addLiveIn(*i); + } + + MF.push_front(PostStackMBB); + MF.push_front(AllocMBB); + MF.push_front(GetMBB); + MF.push_front(McrMBB); + MF.push_front(PrevStackMBB); + + // The required stack size that is aligned to ARM constant criterion. + AlignedStackSize = alignToARMConstant(StackSize); + + // When the frame size is less than 256 we just compare the stack + // boundary directly to the value of the stack pointer, per gcc. + bool CompareStackPointer = AlignedStackSize < kSplitStackAvailable; + + // We will use two of the callee save registers as scratch registers so we + // need to save those registers onto the stack. + // We will use SR0 to hold stack limit and SR1 to hold the stack size + // requested and arguments for __morestack(). + // SR0: Scratch Register #0 + // SR1: Scratch Register #1 + // push {SR0, SR1} + if (Thumb) { + AddDefaultPred(BuildMI(PrevStackMBB, DL, TII.get(ARM::tPUSH))) + .addReg(ScratchReg0).addReg(ScratchReg1); + } else { + AddDefaultPred(BuildMI(PrevStackMBB, DL, TII.get(ARM::STMDB_UPD)) + .addReg(ARM::SP, RegState::Define).addReg(ARM::SP)) + .addReg(ScratchReg0).addReg(ScratchReg1); + } + + // Emit the relevant DWARF information about the change in stack pointer as + // well as where to find both r4 and r5 (the callee-save registers) + CFIIndex = + MMI.addFrameInst(MCCFIInstruction::createDefCfaOffset(nullptr, -8)); + BuildMI(PrevStackMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( + nullptr, MRI->getDwarfRegNum(ScratchReg1, true), -4)); + BuildMI(PrevStackMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( + nullptr, MRI->getDwarfRegNum(ScratchReg0, true), -8)); + BuildMI(PrevStackMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + // mov SR1, sp + if (Thumb) { + AddDefaultPred(BuildMI(McrMBB, DL, TII.get(ARM::tMOVr), ScratchReg1) + .addReg(ARM::SP)); + } else if (CompareStackPointer) { + AddDefaultPred(BuildMI(McrMBB, DL, TII.get(ARM::MOVr), ScratchReg1) + .addReg(ARM::SP)).addReg(0); + } + + // sub SR1, sp, #StackSize + if (!CompareStackPointer && Thumb) { + AddDefaultPred( + AddDefaultCC(BuildMI(McrMBB, DL, TII.get(ARM::tSUBi8), ScratchReg1)) + .addReg(ScratchReg1).addImm(AlignedStackSize)); + } else if (!CompareStackPointer) { + AddDefaultPred(BuildMI(McrMBB, DL, TII.get(ARM::SUBri), ScratchReg1) + .addReg(ARM::SP).addImm(AlignedStackSize)).addReg(0); + } + + if (Thumb && ST->isThumb1Only()) { + unsigned PCLabelId = ARMFI->createPICLabelUId(); + ARMConstantPoolValue *NewCPV = ARMConstantPoolSymbol::Create( + MF.getFunction()->getContext(), "__STACK_LIMIT", PCLabelId, 0); + MachineConstantPool *MCP = MF.getConstantPool(); + unsigned CPI = MCP->getConstantPoolIndex(NewCPV, MF.getAlignment()); + + // ldr SR0, [pc, offset(STACK_LIMIT)] + AddDefaultPred(BuildMI(GetMBB, DL, TII.get(ARM::tLDRpci), ScratchReg0) + .addConstantPoolIndex(CPI)); + + // ldr SR0, [SR0] + AddDefaultPred(BuildMI(GetMBB, DL, TII.get(ARM::tLDRi), ScratchReg0) + .addReg(ScratchReg0).addImm(0)); + } else { + // Get TLS base address from the coprocessor + // mrc p15, #0, SR0, c13, c0, #3 + AddDefaultPred(BuildMI(McrMBB, DL, TII.get(ARM::MRC), ScratchReg0) + .addImm(15) + .addImm(0) + .addImm(13) + .addImm(0) + .addImm(3)); + + // Use the last tls slot on android and a private field of the TCP on linux. + assert(ST->isTargetAndroid() || ST->isTargetLinux()); + unsigned TlsOffset = ST->isTargetAndroid() ? 63 : 1; + + // Get the stack limit from the right offset + // ldr SR0, [sr0, #4 * TlsOffset] + AddDefaultPred(BuildMI(GetMBB, DL, TII.get(ARM::LDRi12), ScratchReg0) + .addReg(ScratchReg0).addImm(4 * TlsOffset)); + } + + // Compare stack limit with stack size requested. + // cmp SR0, SR1 + Opcode = Thumb ? ARM::tCMPr : ARM::CMPrr; + AddDefaultPred(BuildMI(GetMBB, DL, TII.get(Opcode)) + .addReg(ScratchReg0) + .addReg(ScratchReg1)); + + // This jump is taken if StackLimit < SP - stack required. + Opcode = Thumb ? ARM::tBcc : ARM::Bcc; + BuildMI(GetMBB, DL, TII.get(Opcode)).addMBB(PostStackMBB) + .addImm(ARMCC::LO) + .addReg(ARM::CPSR); + + + // Calling __morestack(StackSize, Size of stack arguments). + // __morestack knows that the stack size requested is in SR0(r4) + // and amount size of stack arguments is in SR1(r5). + + // Pass first argument for the __morestack by Scratch Register #0. + // The amount size of stack required + if (Thumb) { + AddDefaultPred(AddDefaultCC(BuildMI(AllocMBB, DL, TII.get(ARM::tMOVi8), + ScratchReg0)).addImm(AlignedStackSize)); + } else { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::MOVi), ScratchReg0) + .addImm(AlignedStackSize)).addReg(0); + } + // Pass second argument for the __morestack by Scratch Register #1. + // The amount size of stack consumed to save function arguments. + if (Thumb) { + AddDefaultPred( + AddDefaultCC(BuildMI(AllocMBB, DL, TII.get(ARM::tMOVi8), ScratchReg1)) + .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()))); + } else { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::MOVi), ScratchReg1) + .addImm(alignToARMConstant(ARMFI->getArgumentStackSize()))) + .addReg(0); + } + + // push {lr} - Save return address of this function. + if (Thumb) { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::tPUSH))) + .addReg(ARM::LR); + } else { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::STMDB_UPD)) + .addReg(ARM::SP, RegState::Define) + .addReg(ARM::SP)) + .addReg(ARM::LR); + } + + // Emit the DWARF info about the change in stack as well as where to find the + // previous link register + CFIIndex = + MMI.addFrameInst(MCCFIInstruction::createDefCfaOffset(nullptr, -12)); + BuildMI(AllocMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset( + nullptr, MRI->getDwarfRegNum(ARM::LR, true), -12)); + BuildMI(AllocMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + // Call __morestack(). + if (Thumb) { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::tBL))) + .addExternalSymbol("__morestack"); + } else { + BuildMI(AllocMBB, DL, TII.get(ARM::BL)) + .addExternalSymbol("__morestack"); + } + + // pop {lr} - Restore return address of this original function. + if (Thumb) { + if (ST->isThumb1Only()) { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::tPOP))) + .addReg(ScratchReg0); + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::tMOVr), ARM::LR) + .addReg(ScratchReg0)); + } else { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::t2LDR_POST)) + .addReg(ARM::LR, RegState::Define) + .addReg(ARM::SP, RegState::Define) + .addReg(ARM::SP) + .addImm(4)); + } + } else { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::LDMIA_UPD)) + .addReg(ARM::SP, RegState::Define) + .addReg(ARM::SP)) + .addReg(ARM::LR); + } + + // Restore SR0 and SR1 in case of __morestack() was called. + // __morestack() will skip PostStackMBB block so we need to restore + // scratch registers from here. + // pop {SR0, SR1} + if (Thumb) { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::tPOP))) + .addReg(ScratchReg0) + .addReg(ScratchReg1); + } else { + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(ARM::LDMIA_UPD)) + .addReg(ARM::SP, RegState::Define) + .addReg(ARM::SP)) + .addReg(ScratchReg0) + .addReg(ScratchReg1); + } + + // Update the CFA offset now that we've popped + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfaOffset(nullptr, 0)); + BuildMI(AllocMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + // bx lr - Return from this function. + Opcode = Thumb ? ARM::tBX_RET : ARM::BX_RET; + AddDefaultPred(BuildMI(AllocMBB, DL, TII.get(Opcode))); + + // Restore SR0 and SR1 in case of __morestack() was not called. + // pop {SR0, SR1} + if (Thumb) { + AddDefaultPred(BuildMI(PostStackMBB, DL, TII.get(ARM::tPOP))) + .addReg(ScratchReg0) + .addReg(ScratchReg1); + } else { + AddDefaultPred(BuildMI(PostStackMBB, DL, TII.get(ARM::LDMIA_UPD)) + .addReg(ARM::SP, RegState::Define) + .addReg(ARM::SP)) + .addReg(ScratchReg0) + .addReg(ScratchReg1); + } + + // Update the CFA offset now that we've popped + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfaOffset(nullptr, 0)); + BuildMI(PostStackMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + // Tell debuggers that r4 and r5 are now the same as they were in the + // previous function, that they're the "Same Value". + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createSameValue( + nullptr, MRI->getDwarfRegNum(ScratchReg0, true))); + BuildMI(PostStackMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + CFIIndex = MMI.addFrameInst(MCCFIInstruction::createSameValue( + nullptr, MRI->getDwarfRegNum(ScratchReg1, true))); + BuildMI(PostStackMBB, DL, TII.get(TargetOpcode::CFI_INSTRUCTION)) + .addCFIIndex(CFIIndex); + + // Organizing MBB lists + PostStackMBB->addSuccessor(&prologueMBB); + + AllocMBB->addSuccessor(PostStackMBB); + + GetMBB->addSuccessor(PostStackMBB); + GetMBB->addSuccessor(AllocMBB); + + McrMBB->addSuccessor(GetMBB); + + PrevStackMBB->addSuccessor(McrMBB); + +#ifdef XDEBUG + MF.verify(); +#endif +}