diff options
Diffstat (limited to 'contrib/llvm/lib/Target/X86/X86FrameLowering.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/X86/X86FrameLowering.cpp | 342 |
1 files changed, 299 insertions, 43 deletions
diff --git a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp index 369589d..54cbd40 100644 --- a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -17,18 +17,18 @@ #include "X86MachineFunctionInfo.h" #include "X86Subtarget.h" #include "X86TargetMachine.h" -#include "llvm/Function.h" +#include "llvm/ADT/SmallSet.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/IR/DataLayout.h" +#include "llvm/IR/Function.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCSymbol.h" -#include "llvm/DataLayout.h" -#include "llvm/Target/TargetOptions.h" #include "llvm/Support/CommandLine.h" -#include "llvm/ADT/SmallSet.h" +#include "llvm/Target/TargetOptions.h" using namespace llvm; @@ -50,13 +50,13 @@ bool X86FrameLowering::hasFP(const MachineFunction &MF) const { return (MF.getTarget().Options.DisableFramePointerElim(MF) || RegInfo->needsStackRealignment(MF) || MFI->hasVarSizedObjects() || - MFI->isFrameAddressTaken() || + MFI->isFrameAddressTaken() || MF.hasMSInlineAsm() || MF.getInfo<X86MachineFunctionInfo>()->getForceFramePointer() || MMI.callsUnwindInit() || MMI.callsEHReturn()); } -static unsigned getSUBriOpcode(unsigned is64Bit, int64_t Imm) { - if (is64Bit) { +static unsigned getSUBriOpcode(unsigned IsLP64, int64_t Imm) { + if (IsLP64) { if (isInt<8>(Imm)) return X86::SUB64ri8; return X86::SUB64ri32; @@ -67,8 +67,8 @@ static unsigned getSUBriOpcode(unsigned is64Bit, int64_t Imm) { } } -static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) { - if (is64Bit) { +static unsigned getADDriOpcode(unsigned IsLP64, int64_t Imm) { + if (IsLP64) { if (isInt<8>(Imm)) return X86::ADD64ri8; return X86::ADD64ri32; @@ -79,8 +79,8 @@ static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) { } } -static unsigned getLEArOpcode(unsigned is64Bit) { - return is64Bit ? X86::LEA64r : X86::LEA32r; +static unsigned getLEArOpcode(unsigned IsLP64) { + return IsLP64 ? X86::LEA64r : X86::LEA32r; } /// findDeadCallerSavedReg - Return a caller-saved register that isn't live @@ -145,17 +145,17 @@ static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB, static void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, unsigned StackPtr, int64_t NumBytes, - bool Is64Bit, bool UseLEA, + bool Is64Bit, bool IsLP64, bool UseLEA, const TargetInstrInfo &TII, const TargetRegisterInfo &TRI) { bool isSub = NumBytes < 0; uint64_t Offset = isSub ? -NumBytes : NumBytes; unsigned Opc; if (UseLEA) - Opc = getLEArOpcode(Is64Bit); + Opc = getLEArOpcode(IsLP64); else Opc = isSub - ? getSUBriOpcode(Is64Bit, Offset) - : getADDriOpcode(Is64Bit, Offset); + ? getSUBriOpcode(IsLP64, Offset) + : getADDriOpcode(IsLP64, Offset); uint64_t Chunk = (1LL << 31) - 1; DebugLoc DL = MBB.findDebugLoc(MBBI); @@ -625,6 +625,22 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { return CompactUnwindEncoding; } +/// usesTheStack - This function checks if any of the users of EFLAGS +/// copies the EFLAGS. We know that the code that lowers COPY of EFLAGS has +/// to use the stack, and if we don't adjust the stack we clobber the first +/// frame index. +/// See X86InstrInfo::copyPhysReg. +static bool usesTheStack(MachineFunction &MF) { + MachineRegisterInfo &MRI = MF.getRegInfo(); + + for (MachineRegisterInfo::reg_iterator ri = MRI.reg_begin(X86::EFLAGS), + re = MRI.reg_end(); ri != re; ++ri) + if (ri->isCopy()) + return true; + + return false; +} + /// emitPrologue - Push callee-saved registers onto the stack, which /// automatically adjust the stack pointer. Adjust the stack pointer to allocate /// space for local variables. Also emit labels used by the exception handler to @@ -644,6 +660,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { uint64_t StackSize = MFI->getStackSize(); // Number of bytes to allocate. bool HasFP = hasFP(MF); bool Is64Bit = STI.is64Bit(); + bool IsLP64 = STI.isTarget64BitLP64(); bool IsWin64 = STI.isTargetWin64(); bool UseLEA = STI.useLeaForSP(); unsigned StackAlign = getStackAlignment(); @@ -673,12 +690,15 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { // If this is x86-64 and the Red Zone is not disabled, if we are a leaf // function, and use up to 128 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). - if (Is64Bit && !Fn->getFnAttributes().hasAttribute(Attributes::NoRedZone) && + // stack pointer (we fit in the Red Zone). We also check that we don't + // push and pop from the stack. + if (Is64Bit && !Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex, + Attribute::NoRedZone) && !RegInfo->needsStackRealignment(MF) && !MFI->hasVarSizedObjects() && // No dynamic alloca. !MFI->adjustsStack() && // No calls. !IsWin64 && // Win64 has no Red Zone + !usesTheStack(MF) && // Don't push and pop. !MF.getTarget().Options.EnableSegmentedStacks) { // Regular stack uint64_t MinSize = X86FI->getCalleeSavedFrameSize(); if (HasFP) MinSize += SlotSize; @@ -692,7 +712,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { if (TailCallReturnAddrDelta < 0) { MachineInstr *MI = BuildMI(MBB, MBBI, DL, - TII.get(getSUBriOpcode(Is64Bit, -TailCallReturnAddrDelta)), + TII.get(getSUBriOpcode(IsLP64, -TailCallReturnAddrDelta)), StackPtr) .addReg(StackPtr) .addImm(-TailCallReturnAddrDelta) @@ -908,7 +928,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { // MSVC x64's __chkstk needs to adjust %rsp. // FIXME: %rax preserves the offset and should be available. if (isSPUpdateNeeded) - emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, + emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, IsLP64, UseLEA, TII, *RegInfo); if (isEAXAlive) { @@ -920,7 +940,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { MBB.insert(MBBI, MI); } } else if (NumBytes) - emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, + emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, IsLP64, UseLEA, TII, *RegInfo); // If we need a base pointer, set it up here. It's whatever the value @@ -977,6 +997,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, unsigned RetOpcode = MBBI->getOpcode(); DebugLoc DL = MBBI->getDebugLoc(); bool Is64Bit = STI.is64Bit(); + bool IsLP64 = STI.isTarget64BitLP64(); bool UseLEA = STI.useLeaForSP(); unsigned StackAlign = getStackAlignment(); unsigned SlotSize = RegInfo->getSlotSize(); @@ -1062,7 +1083,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, if (RegInfo->needsStackRealignment(MF)) MBBI = FirstCSPop; if (CSSize != 0) { - unsigned Opc = getLEArOpcode(Is64Bit); + unsigned Opc = getLEArOpcode(IsLP64); addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr), FramePtr, false, -CSSize); } else { @@ -1072,7 +1093,8 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, } } else if (NumBytes) { // Adjust stack pointer back: ESP += numbytes. - emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, UseLEA, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, IsLP64, UseLEA, + TII, *RegInfo); } // We're returning from function via eh_return. @@ -1107,7 +1129,8 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, if (Offset) { // Check for possible merge with preceding ADD instruction. Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true); - emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, UseLEA, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, IsLP64, + UseLEA, TII, *RegInfo); } // Jump to label or value in register. @@ -1138,7 +1161,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, } MachineInstr *NewMI = prior(MBBI); - NewMI->copyImplicitOps(MBBI); + NewMI->copyImplicitOps(MF, MBBI); // Delete the pseudo instruction TCRETURN. MBB.erase(MBBI); @@ -1150,7 +1173,8 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, // Check for possible merge with preceding ADD instruction. delta += mergeSPUpdates(MBB, MBBI, StackPtr, true); - emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, UseLEA, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, IsLP64, UseLEA, TII, + *RegInfo); } } @@ -1362,17 +1386,25 @@ HasNestArgument(const MachineFunction *MF) { return false; } - -/// GetScratchRegister - Get a register for performing work in the segmented -/// stack prologue. Depending on platform and the properties of the function -/// either one or two registers will be needed. Set primary to true for -/// the first register, false for the second. +/// GetScratchRegister - Get a temp register for performing work in the +/// segmented stack and the Erlang/HiPE stack prologue. Depending on platform +/// and the properties of the function either one or two registers will be +/// needed. Set primary to true for the first register, false for the second. static unsigned GetScratchRegister(bool Is64Bit, const MachineFunction &MF, bool Primary) { + CallingConv::ID CallingConvention = MF.getFunction()->getCallingConv(); + + // Erlang stuff. + if (CallingConvention == CallingConv::HiPE) { + if (Is64Bit) + return Primary ? X86::R14 : X86::R13; + else + return Primary ? X86::EBX : X86::EDI; + } + if (Is64Bit) return Primary ? X86::R11 : X86::R12; - CallingConv::ID CallingConvention = MF.getFunction()->getCallingConv(); bool IsNested = HasNestArgument(&MF); if (CallingConvention == CallingConv::X86_FastCall || @@ -1400,7 +1432,6 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { bool Is64Bit = STI.is64Bit(); unsigned TlsReg, TlsOffset; DebugLoc DL; - const X86Subtarget *ST = &MF.getTarget().getSubtarget<X86Subtarget>(); unsigned ScratchReg = GetScratchRegister(Is64Bit, MF, true); assert(!MF.getRegInfo().isLiveIn(ScratchReg) && @@ -1408,8 +1439,8 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { if (MF.getFunction()->isVarArg()) report_fatal_error("Segmented stacks do not support vararg functions."); - if (!ST->isTargetLinux() && !ST->isTargetDarwin() && - !ST->isTargetWin32() && !ST->isTargetFreeBSD()) + if (!STI.isTargetLinux() && !STI.isTargetDarwin() && + !STI.isTargetWin32() && !STI.isTargetFreeBSD()) report_fatal_error("Segmented stacks not supported on this platform."); MachineBasicBlock *allocMBB = MF.CreateMachineBasicBlock(); @@ -1447,13 +1478,13 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { // Read the limit off the current stacklet off the stack_guard location. if (Is64Bit) { - if (ST->isTargetLinux()) { + if (STI.isTargetLinux()) { TlsReg = X86::FS; TlsOffset = 0x70; - } else if (ST->isTargetDarwin()) { + } else if (STI.isTargetDarwin()) { TlsReg = X86::GS; TlsOffset = 0x60 + 90*8; // See pthread_machdep.h. Steal TLS slot 90. - } else if (ST->isTargetFreeBSD()) { + } else if (STI.isTargetFreeBSD()) { TlsReg = X86::FS; TlsOffset = 0x18; } else { @@ -1469,16 +1500,16 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { BuildMI(checkMBB, DL, TII.get(X86::CMP64rm)).addReg(ScratchReg) .addReg(0).addImm(1).addReg(0).addImm(TlsOffset).addReg(TlsReg); } else { - if (ST->isTargetLinux()) { + if (STI.isTargetLinux()) { TlsReg = X86::GS; TlsOffset = 0x30; - } else if (ST->isTargetDarwin()) { + } else if (STI.isTargetDarwin()) { TlsReg = X86::GS; TlsOffset = 0x48 + 90*4; - } else if (ST->isTargetWin32()) { + } else if (STI.isTargetWin32()) { TlsReg = X86::FS; TlsOffset = 0x14; // pvArbitrary, reserved for application use - } else if (ST->isTargetFreeBSD()) { + } else if (STI.isTargetFreeBSD()) { report_fatal_error("Segmented stacks not supported on FreeBSD i386."); } else { report_fatal_error("Segmented stacks not supported on this platform."); @@ -1490,10 +1521,10 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP) .addImm(1).addReg(0).addImm(-StackSize).addReg(0); - if (ST->isTargetLinux() || ST->isTargetWin32()) { + if (STI.isTargetLinux() || STI.isTargetWin32()) { BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)).addReg(ScratchReg) .addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg); - } else if (ST->isTargetDarwin()) { + } else if (STI.isTargetDarwin()) { // TlsOffset doesn't fit into a mod r/m byte so we need an extra register unsigned ScratchReg2; @@ -1579,3 +1610,228 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { MF.verify(); #endif } + +/// Erlang programs may need a special prologue to handle the stack size they +/// might need at runtime. That is because Erlang/OTP does not implement a C +/// stack but uses a custom implementation of hybrid stack/heap architecture. +/// (for more information see Eric Stenman's Ph.D. thesis: +/// http://publications.uu.se/uu/fulltext/nbn_se_uu_diva-2688.pdf) +/// +/// CheckStack: +/// temp0 = sp - MaxStack +/// if( temp0 < SP_LIMIT(P) ) goto IncStack else goto OldStart +/// OldStart: +/// ... +/// IncStack: +/// call inc_stack # doubles the stack space +/// temp0 = sp - MaxStack +/// if( temp0 < SP_LIMIT(P) ) goto IncStack else goto OldStart +void X86FrameLowering::adjustForHiPEPrologue(MachineFunction &MF) const { + const X86InstrInfo &TII = *TM.getInstrInfo(); + MachineFrameInfo *MFI = MF.getFrameInfo(); + const unsigned SlotSize = TM.getRegisterInfo()->getSlotSize(); + const bool Is64Bit = STI.is64Bit(); + DebugLoc DL; + // HiPE-specific values + const unsigned HipeLeafWords = 24; + const unsigned CCRegisteredArgs = Is64Bit ? 6 : 5; + const unsigned Guaranteed = HipeLeafWords * SlotSize; + unsigned CallerStkArity = MF.getFunction()->arg_size() > CCRegisteredArgs ? + MF.getFunction()->arg_size() - CCRegisteredArgs : 0; + unsigned MaxStack = MFI->getStackSize() + CallerStkArity*SlotSize + SlotSize; + + assert(STI.isTargetLinux() && + "HiPE prologue is only supported on Linux operating systems."); + + // Compute the largest caller's frame that is needed to fit the callees' + // frames. This 'MaxStack' is computed from: + // + // a) the fixed frame size, which is the space needed for all spilled temps, + // b) outgoing on-stack parameter areas, and + // c) the minimum stack space this function needs to make available for the + // functions it calls (a tunable ABI property). + if (MFI->hasCalls()) { + unsigned MoreStackForCalls = 0; + + for (MachineFunction::iterator MBBI = MF.begin(), MBBE = MF.end(); + MBBI != MBBE; ++MBBI) + for (MachineBasicBlock::iterator MI = MBBI->begin(), ME = MBBI->end(); + MI != ME; ++MI) { + if (!MI->isCall()) + continue; + + // Get callee operand. + const MachineOperand &MO = MI->getOperand(0); + + // Only take account of global function calls (no closures etc.). + if (!MO.isGlobal()) + continue; + + const Function *F = dyn_cast<Function>(MO.getGlobal()); + if (!F) + continue; + + // Do not update 'MaxStack' for primitive and built-in functions + // (encoded with names either starting with "erlang."/"bif_" or not + // having a ".", such as a simple <Module>.<Function>.<Arity>, or an + // "_", such as the BIF "suspend_0") as they are executed on another + // stack. + if (F->getName().find("erlang.") != StringRef::npos || + F->getName().find("bif_") != StringRef::npos || + F->getName().find_first_of("._") == StringRef::npos) + continue; + + unsigned CalleeStkArity = + F->arg_size() > CCRegisteredArgs ? F->arg_size()-CCRegisteredArgs : 0; + if (HipeLeafWords - 1 > CalleeStkArity) + MoreStackForCalls = std::max(MoreStackForCalls, + (HipeLeafWords - 1 - CalleeStkArity) * SlotSize); + } + MaxStack += MoreStackForCalls; + } + + // If the stack frame needed is larger than the guaranteed then runtime checks + // and calls to "inc_stack_0" BIF should be inserted in the assembly prologue. + if (MaxStack > Guaranteed) { + MachineBasicBlock &prologueMBB = MF.front(); + MachineBasicBlock *stackCheckMBB = MF.CreateMachineBasicBlock(); + MachineBasicBlock *incStackMBB = MF.CreateMachineBasicBlock(); + + for (MachineBasicBlock::livein_iterator I = prologueMBB.livein_begin(), + E = prologueMBB.livein_end(); I != E; I++) { + stackCheckMBB->addLiveIn(*I); + incStackMBB->addLiveIn(*I); + } + + MF.push_front(incStackMBB); + MF.push_front(stackCheckMBB); + + unsigned ScratchReg, SPReg, PReg, SPLimitOffset; + unsigned LEAop, CMPop, CALLop; + if (Is64Bit) { + SPReg = X86::RSP; + PReg = X86::RBP; + LEAop = X86::LEA64r; + CMPop = X86::CMP64rm; + CALLop = X86::CALL64pcrel32; + SPLimitOffset = 0x90; + } else { + SPReg = X86::ESP; + PReg = X86::EBP; + LEAop = X86::LEA32r; + CMPop = X86::CMP32rm; + CALLop = X86::CALLpcrel32; + SPLimitOffset = 0x4c; + } + + ScratchReg = GetScratchRegister(Is64Bit, MF, true); + assert(!MF.getRegInfo().isLiveIn(ScratchReg) && + "HiPE prologue scratch register is live-in"); + + // Create new MBB for StackCheck: + addRegOffset(BuildMI(stackCheckMBB, DL, TII.get(LEAop), ScratchReg), + SPReg, false, -MaxStack); + // SPLimitOffset is in a fixed heap location (pointed by BP). + addRegOffset(BuildMI(stackCheckMBB, DL, TII.get(CMPop)) + .addReg(ScratchReg), PReg, false, SPLimitOffset); + BuildMI(stackCheckMBB, DL, TII.get(X86::JAE_4)).addMBB(&prologueMBB); + + // Create new MBB for IncStack: + BuildMI(incStackMBB, DL, TII.get(CALLop)). + addExternalSymbol("inc_stack_0"); + addRegOffset(BuildMI(incStackMBB, DL, TII.get(LEAop), ScratchReg), + SPReg, false, -MaxStack); + addRegOffset(BuildMI(incStackMBB, DL, TII.get(CMPop)) + .addReg(ScratchReg), PReg, false, SPLimitOffset); + BuildMI(incStackMBB, DL, TII.get(X86::JLE_4)).addMBB(incStackMBB); + + stackCheckMBB->addSuccessor(&prologueMBB, 99); + stackCheckMBB->addSuccessor(incStackMBB, 1); + incStackMBB->addSuccessor(&prologueMBB, 99); + incStackMBB->addSuccessor(incStackMBB, 1); + } +#ifdef XDEBUG + MF.verify(); +#endif +} + +void X86FrameLowering:: +eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, + MachineBasicBlock::iterator I) const { + const X86InstrInfo &TII = *TM.getInstrInfo(); + const X86RegisterInfo &RegInfo = *TM.getRegisterInfo(); + unsigned StackPtr = RegInfo.getStackRegister(); + bool reseveCallFrame = hasReservedCallFrame(MF); + int Opcode = I->getOpcode(); + bool isDestroy = Opcode == TII.getCallFrameDestroyOpcode(); + bool IsLP64 = STI.isTarget64BitLP64(); + DebugLoc DL = I->getDebugLoc(); + uint64_t Amount = !reseveCallFrame ? I->getOperand(0).getImm() : 0; + uint64_t CalleeAmt = isDestroy ? I->getOperand(1).getImm() : 0; + I = MBB.erase(I); + + if (!reseveCallFrame) { + // If the stack pointer can be changed after prologue, turn the + // adjcallstackup instruction into a 'sub ESP, <amt>' and the + // adjcallstackdown instruction into 'add ESP, <amt>' + // TODO: consider using push / pop instead of sub + store / add + if (Amount == 0) + return; + + // We need to keep the stack aligned properly. To do this, we round the + // amount of space needed for the outgoing arguments up to the next + // alignment boundary. + unsigned StackAlign = TM.getFrameLowering()->getStackAlignment(); + Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign; + + MachineInstr *New = 0; + if (Opcode == TII.getCallFrameSetupOpcode()) { + New = BuildMI(MF, DL, TII.get(getSUBriOpcode(IsLP64, Amount)), + StackPtr) + .addReg(StackPtr) + .addImm(Amount); + } else { + assert(Opcode == TII.getCallFrameDestroyOpcode()); + + // Factor out the amount the callee already popped. + Amount -= CalleeAmt; + + if (Amount) { + unsigned Opc = getADDriOpcode(IsLP64, Amount); + New = BuildMI(MF, DL, TII.get(Opc), StackPtr) + .addReg(StackPtr).addImm(Amount); + } + } + + if (New) { + // The EFLAGS implicit def is dead. + New->getOperand(3).setIsDead(); + + // Replace the pseudo instruction with a new instruction. + MBB.insert(I, New); + } + + return; + } + + if (Opcode == TII.getCallFrameDestroyOpcode() && CalleeAmt) { + // If we are performing frame pointer elimination and if the callee pops + // something off the stack pointer, add it back. We do this until we have + // more advanced stack pointer tracking ability. + unsigned Opc = getSUBriOpcode(IsLP64, CalleeAmt); + MachineInstr *New = BuildMI(MF, DL, TII.get(Opc), StackPtr) + .addReg(StackPtr).addImm(CalleeAmt); + + // The EFLAGS implicit def is dead. + New->getOperand(3).setIsDead(); + + // We are not tracking the stack pointer adjustment by the callee, so make + // sure we restore the stack pointer immediately after the call, there may + // be spill code inserted between the CALL and ADJCALLSTACKUP instructions. + MachineBasicBlock::iterator B = MBB.begin(); + while (I != B && !llvm::prior(I)->isCall()) + --I; + MBB.insert(I, New); + } +} + |
