diff options
Diffstat (limited to 'contrib/llvm/lib/Target/X86/X86FrameLowering.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/X86/X86FrameLowering.cpp | 382 |
1 files changed, 237 insertions, 145 deletions
diff --git a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp index d54f4ae..000e375 100644 --- a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -1,4 +1,4 @@ -//=======- X86FrameLowering.cpp - X86 Frame Information --------*- C++ -*-====// +//===-- X86FrameLowering.cpp - X86 Frame Information ----------------------===// // // The LLVM Compiler Infrastructure // @@ -47,7 +47,7 @@ bool X86FrameLowering::hasFP(const MachineFunction &MF) const { const MachineModuleInfo &MMI = MF.getMMI(); const TargetRegisterInfo *RI = TM.getRegisterInfo(); - return (DisableFramePointerElim(MF) || + return (MF.getTarget().Options.DisableFramePointerElim(MF) || RI->needsStackRealignment(MF) || MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken() || @@ -79,6 +79,10 @@ static unsigned getADDriOpcode(unsigned is64Bit, int64_t Imm) { } } +static unsigned getLEArOpcode(unsigned is64Bit) { + return is64Bit ? X86::LEA64r : X86::LEA32r; +} + /// findDeadCallerSavedReg - Return a caller-saved register that isn't live /// when it reaches the "return" instruction. We can then pop a stack object /// to this register without worry about clobbering it. @@ -91,11 +95,11 @@ static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB, if (!F || MF->getMMI().callsEHReturn()) return 0; - static const unsigned CallerSavedRegs32Bit[] = { + static const uint16_t CallerSavedRegs32Bit[] = { X86::EAX, X86::EDX, X86::ECX, 0 }; - static const unsigned CallerSavedRegs64Bit[] = { + static const uint16_t CallerSavedRegs64Bit[] = { X86::RAX, X86::RDX, X86::RCX, X86::RSI, X86::RDI, X86::R8, X86::R9, X86::R10, X86::R11, 0 }; @@ -113,7 +117,7 @@ static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB, case X86::TCRETURNmi64: case X86::EH_RETURN: case X86::EH_RETURN64: { - SmallSet<unsigned, 8> Uses; + SmallSet<uint16_t, 8> Uses; for (unsigned i = 0, e = MBBI->getNumOperands(); i != e; ++i) { MachineOperand &MO = MBBI->getOperand(i); if (!MO.isReg() || MO.isDef()) @@ -121,11 +125,11 @@ static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB, unsigned Reg = MO.getReg(); if (!Reg) continue; - for (const unsigned *AsI = TRI.getOverlaps(Reg); *AsI; ++AsI) + for (const uint16_t *AsI = TRI.getOverlaps(Reg); *AsI; ++AsI) Uses.insert(*AsI); } - const unsigned *CS = Is64Bit ? CallerSavedRegs64Bit : CallerSavedRegs32Bit; + const uint16_t *CS = Is64Bit ? CallerSavedRegs64Bit : CallerSavedRegs32Bit; for (; *CS; ++CS) if (!Uses.count(*CS)) return *CS; @@ -141,13 +145,18 @@ static unsigned findDeadCallerSavedReg(MachineBasicBlock &MBB, static void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, unsigned StackPtr, int64_t NumBytes, - bool Is64Bit, const TargetInstrInfo &TII, - const TargetRegisterInfo &TRI) { + bool Is64Bit, bool UseLEA, + const TargetInstrInfo &TII, const TargetRegisterInfo &TRI) { bool isSub = NumBytes < 0; uint64_t Offset = isSub ? -NumBytes : NumBytes; - unsigned Opc = isSub ? - getSUBriOpcode(Is64Bit, Offset) : - getADDriOpcode(Is64Bit, Offset); + unsigned Opc; + if (UseLEA) + Opc = getLEArOpcode(Is64Bit); + else + Opc = isSub + ? getSUBriOpcode(Is64Bit, Offset) + : getADDriOpcode(Is64Bit, Offset); + uint64_t Chunk = (1LL << 31) - 1; DebugLoc DL = MBB.findDebugLoc(MBBI); @@ -171,13 +180,21 @@ void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, } } - MachineInstr *MI = - BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr) - .addReg(StackPtr) - .addImm(ThisVal); + MachineInstr *MI = NULL; + + if (UseLEA) { + MI = addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr), + StackPtr, false, isSub ? -ThisVal : ThisVal); + } else { + MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr) + .addReg(StackPtr) + .addImm(ThisVal); + MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead. + } + if (isSub) MI->setFlag(MachineInstr::FrameSetup); - MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead. + Offset -= ThisVal; } } @@ -191,7 +208,8 @@ void mergeSPUpdatesUp(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, MachineBasicBlock::iterator PI = prior(MBBI); unsigned Opc = PI->getOpcode(); if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 || - Opc == X86::ADD32ri || Opc == X86::ADD32ri8) && + Opc == X86::ADD32ri || Opc == X86::ADD32ri8 || + Opc == X86::LEA32r || Opc == X86::LEA64_32r) && PI->getOperand(0).getReg() == StackPtr) { if (NumBytes) *NumBytes += PI->getOperand(2).getImm(); @@ -210,7 +228,7 @@ static void mergeSPUpdatesDown(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, unsigned StackPtr, uint64_t *NumBytes = NULL) { - // FIXME: THIS ISN'T RUN!!! + // FIXME: THIS ISN'T RUN!!! return; if (MBBI == MBB.end()) return; @@ -237,8 +255,8 @@ void mergeSPUpdatesDown(MachineBasicBlock &MBB, } /// mergeSPUpdates - Checks the instruction before/after the passed -/// instruction. If it is an ADD/SUB instruction it is deleted argument and the -/// stack adjustment is returned as a positive value for ADD and a negative for +/// instruction. If it is an ADD/SUB/LEA instruction it is deleted argument and the +/// stack adjustment is returned as a positive value for ADD/LEA and a negative for /// SUB. static int mergeSPUpdates(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, @@ -254,7 +272,8 @@ static int mergeSPUpdates(MachineBasicBlock &MBB, int Offset = 0; if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 || - Opc == X86::ADD32ri || Opc == X86::ADD32ri8) && + Opc == X86::ADD32ri || Opc == X86::ADD32ri8 || + Opc == X86::LEA32r || Opc == X86::LEA64_32r) && PI->getOperand(0).getReg() == StackPtr){ Offset += PI->getOperand(2).getImm(); MBB.erase(PI); @@ -351,20 +370,22 @@ void X86FrameLowering::emitCalleeSavedFrameMoves(MachineFunction &MF, /// register. The number corresponds to the enum lists in /// compact_unwind_encoding.h. static int getCompactUnwindRegNum(const unsigned *CURegs, unsigned Reg) { - int Idx = 1; - for (; *CURegs; ++CURegs, ++Idx) + for (int Idx = 1; *CURegs; ++CURegs, ++Idx) if (*CURegs == Reg) return Idx; return -1; } +// Number of registers that can be saved in a compact unwind encoding. +#define CU_NUM_SAVED_REGS 6 + /// encodeCompactUnwindRegistersWithoutFrame - Create the permutation encoding /// used with frameless stacks. It is passed the number of registers to be saved /// and an array of the registers saved. -static uint32_t encodeCompactUnwindRegistersWithoutFrame(unsigned SavedRegs[6], - unsigned RegCount, - bool Is64Bit) { +static uint32_t +encodeCompactUnwindRegistersWithoutFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS], + unsigned RegCount, bool Is64Bit) { // The saved registers are numbered from 1 to 6. In order to encode the order // in which they were saved, we re-number them according to their place in the // register order. The re-numbering is relative to the last re-numbered @@ -385,14 +406,21 @@ static uint32_t encodeCompactUnwindRegistersWithoutFrame(unsigned SavedRegs[6], }; const unsigned *CURegs = (Is64Bit ? CU64BitRegs : CU32BitRegs); - uint32_t RenumRegs[6]; - for (unsigned i = 6 - RegCount; i < 6; ++i) { + for (unsigned i = 0; i != CU_NUM_SAVED_REGS; ++i) { int CUReg = getCompactUnwindRegNum(CURegs, SavedRegs[i]); if (CUReg == -1) return ~0U; SavedRegs[i] = CUReg; + } + // Reverse the list. + std::swap(SavedRegs[0], SavedRegs[5]); + std::swap(SavedRegs[1], SavedRegs[4]); + std::swap(SavedRegs[2], SavedRegs[3]); + + uint32_t RenumRegs[CU_NUM_SAVED_REGS]; + for (unsigned i = CU_NUM_SAVED_REGS - RegCount; i < CU_NUM_SAVED_REGS; ++i) { unsigned Countless = 0; - for (unsigned j = 6 - RegCount; j < i; ++j) + for (unsigned j = CU_NUM_SAVED_REGS - RegCount; j < i; ++j) if (SavedRegs[j] < SavedRegs[i]) ++Countless; @@ -435,8 +463,9 @@ static uint32_t encodeCompactUnwindRegistersWithoutFrame(unsigned SavedRegs[6], /// encodeCompactUnwindRegistersWithFrame - Return the registers encoded for a /// compact encoding with a frame pointer. -static uint32_t encodeCompactUnwindRegistersWithFrame(unsigned SavedRegs[6], - bool Is64Bit) { +static uint32_t +encodeCompactUnwindRegistersWithFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS], + bool Is64Bit) { static const unsigned CU32BitRegs[] = { X86::EBX, X86::ECX, X86::EDX, X86::EDI, X86::ESI, X86::EBP, 0 }; @@ -446,18 +475,21 @@ static uint32_t encodeCompactUnwindRegistersWithFrame(unsigned SavedRegs[6], const unsigned *CURegs = (Is64Bit ? CU64BitRegs : CU32BitRegs); // Encode the registers in the order they were saved, 3-bits per register. The - // registers are numbered from 1 to 6. + // registers are numbered from 1 to CU_NUM_SAVED_REGS. uint32_t RegEnc = 0; - for (int I = 5; I >= 0; --I) { + for (int I = CU_NUM_SAVED_REGS - 1, Idx = 0; I != -1; --I) { unsigned Reg = SavedRegs[I]; - if (Reg == 0) break; + if (Reg == 0) continue; + int CURegNum = getCompactUnwindRegNum(CURegs, Reg); - if (CURegNum == -1) - return ~0U; - RegEnc |= (CURegNum & 0x7) << (5 - I); + if (CURegNum == -1) return ~0U; + + // Encode the 3-bit register number in order, skipping over 3-bits for each + // register. + RegEnc |= (CURegNum & 0x7) << (Idx++ * 3); } - assert((RegEnc & 0x7FFF) == RegEnc && "Invalid compact register encoding!"); + assert((RegEnc & 0x3FFFF) == RegEnc && "Invalid compact register encoding!"); return RegEnc; } @@ -466,14 +498,11 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { unsigned FramePtr = RegInfo->getFrameRegister(MF); unsigned StackPtr = RegInfo->getStackRegister(); - X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>(); - int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta(); - bool Is64Bit = STI.is64Bit(); bool HasFP = hasFP(MF); - unsigned SavedRegs[6] = { 0, 0, 0, 0, 0, 0 }; - int SavedRegIdx = 6; + unsigned SavedRegs[CU_NUM_SAVED_REGS] = { 0, 0, 0, 0, 0, 0 }; + unsigned SavedRegIdx = 0; unsigned OffsetSize = (Is64Bit ? 8 : 4); @@ -481,14 +510,13 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { unsigned PushInstrSize = 1; unsigned MoveInstr = (Is64Bit ? X86::MOV64rr : X86::MOV32rr); unsigned MoveInstrSize = (Is64Bit ? 3 : 2); - unsigned SubtractInstr = getSUBriOpcode(Is64Bit, -TailCallReturnAddrDelta); unsigned SubtractInstrIdx = (Is64Bit ? 3 : 2); unsigned StackDivide = (Is64Bit ? 8 : 4); unsigned InstrOffset = 0; - unsigned CFAOffset = 0; unsigned StackAdjust = 0; + unsigned StackSize = 0; MachineBasicBlock &MBB = MF.front(); // Prologue is in entry BB. bool ExpectEnd = false; @@ -504,10 +532,10 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { if (Opc == PushInstr) { // If there are too many saved registers, we cannot use compact encoding. - if (--SavedRegIdx < 0) return 0; + if (SavedRegIdx >= CU_NUM_SAVED_REGS) return 0; - SavedRegs[SavedRegIdx] = MI.getOperand(0).getReg(); - CFAOffset += OffsetSize; + SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg(); + StackAdjust += OffsetSize; InstrOffset += PushInstrSize; } else if (Opc == MoveInstr) { unsigned SrcReg = MI.getOperand(1).getReg(); @@ -516,12 +544,14 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { if (DstReg != FramePtr || SrcReg != StackPtr) return 0; - CFAOffset = 0; + StackAdjust = 0; memset(SavedRegs, 0, sizeof(SavedRegs)); + SavedRegIdx = 0; InstrOffset += MoveInstrSize; - } else if (Opc == SubtractInstr) { - if (StackAdjust) - // We all ready have a stack pointer adjustment. + } else if (Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 || + Opc == X86::SUB32ri || Opc == X86::SUB32ri8) { + if (StackSize) + // We already have a stack size. return 0; if (!MI.getOperand(0).isReg() || @@ -532,7 +562,7 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { // %RSP<def> = SUB64ri8 %RSP, 48 return 0; - StackAdjust = MI.getOperand(2).getImm() / StackDivide; + StackSize = MI.getOperand(2).getImm() / StackDivide; SubtractInstrIdx += InstrOffset; ExpectEnd = true; } @@ -540,28 +570,30 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { // Encode that we are using EBP/RBP as the frame pointer. uint32_t CompactUnwindEncoding = 0; - CFAOffset /= StackDivide; + StackAdjust /= StackDivide; if (HasFP) { - if ((CFAOffset & 0xFF) != CFAOffset) + if ((StackAdjust & 0xFF) != StackAdjust) // Offset was too big for compact encoding. return 0; // Get the encoding of the saved registers when we have a frame pointer. uint32_t RegEnc = encodeCompactUnwindRegistersWithFrame(SavedRegs, Is64Bit); - if (RegEnc == ~0U) - return 0; + if (RegEnc == ~0U) return 0; CompactUnwindEncoding |= 0x01000000; - CompactUnwindEncoding |= (CFAOffset & 0xFF) << 16; + CompactUnwindEncoding |= (StackAdjust & 0xFF) << 16; CompactUnwindEncoding |= RegEnc & 0x7FFF; } else { - unsigned FullOffset = CFAOffset + StackAdjust; - if ((FullOffset & 0xFF) == FullOffset) { - // Frameless stack. + ++StackAdjust; + uint32_t TotalStackSize = StackAdjust + StackSize; + if ((TotalStackSize & 0xFF) == TotalStackSize) { + // Frameless stack with a small stack size. CompactUnwindEncoding |= 0x02000000; - CompactUnwindEncoding |= (FullOffset & 0xFF) << 16; + + // Encode the stack size. + CompactUnwindEncoding |= (TotalStackSize & 0xFF) << 16; } else { - if ((CFAOffset & 0x7) != CFAOffset) + if ((StackAdjust & 0x7) != StackAdjust) // The extra stack adjustments are too big for us to handle. return 0; @@ -572,16 +604,21 @@ uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { // instruction. CompactUnwindEncoding |= (SubtractInstrIdx & 0xFF) << 16; - // Encode any extra stack stack changes (done via push instructions). - CompactUnwindEncoding |= (CFAOffset & 0x7) << 13; + // Encode any extra stack stack adjustments (done via push instructions). + CompactUnwindEncoding |= (StackAdjust & 0x7) << 13; } + // Encode the number of registers saved. + CompactUnwindEncoding |= (SavedRegIdx & 0x7) << 10; + // Get the encoding of the saved registers when we don't have a frame // pointer. - uint32_t RegEnc = encodeCompactUnwindRegistersWithoutFrame(SavedRegs, - 6 - SavedRegIdx, - Is64Bit); + uint32_t RegEnc = + encodeCompactUnwindRegistersWithoutFrame(SavedRegs, SavedRegIdx, + Is64Bit); if (RegEnc == ~0U) return 0; + + // Encode the register encoding. CompactUnwindEncoding |= RegEnc & 0x3FF; } @@ -608,6 +645,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { bool HasFP = hasFP(MF); bool Is64Bit = STI.is64Bit(); bool IsWin64 = STI.isTargetWin64(); + bool UseLEA = STI.useLeaForSP(); unsigned StackAlign = getStackAlignment(); unsigned SlotSize = RegInfo->getSlotSize(); unsigned FramePtr = RegInfo->getFrameRegister(MF); @@ -637,10 +675,10 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { // stack pointer (we fit in the Red Zone). if (Is64Bit && !Fn->hasFnAttr(Attribute::NoRedZone) && !RegInfo->needsStackRealignment(MF) && - !MFI->hasVarSizedObjects() && // No dynamic alloca. - !MFI->adjustsStack() && // No calls. - !IsWin64 && // Win64 has no Red Zone - !EnableSegmentedStacks) { // Regular stack + !MFI->hasVarSizedObjects() && // No dynamic alloca. + !MFI->adjustsStack() && // No calls. + !IsWin64 && // Win64 has no Red Zone + !MF.getTarget().Options.EnableSegmentedStacks) { // Regular stack uint64_t MinSize = X86FI->getCalleeSavedFrameSize(); if (HasFP) MinSize += SlotSize; StackSize = std::max(MinSize, StackSize > 128 ? StackSize - 128 : 0); @@ -861,7 +899,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { // FIXME: %rax preserves the offset and should be available. if (isSPUpdateNeeded) emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, - TII, *RegInfo); + UseLEA, TII, *RegInfo); if (isEAXAlive) { // Restore EAX @@ -873,7 +911,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { } } else if (NumBytes) emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, - TII, *RegInfo); + UseLEA, TII, *RegInfo); if (( (!HasFP && NumBytes) || PushedRegs) && needsFrameMoves) { // Mark end of stack pointer adjustment. @@ -917,6 +955,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, unsigned RetOpcode = MBBI->getOpcode(); DebugLoc DL = MBBI->getDebugLoc(); bool Is64Bit = STI.is64Bit(); + bool UseLEA = STI.useLeaForSP(); unsigned StackAlign = getStackAlignment(); unsigned SlotSize = RegInfo->getSlotSize(); unsigned FramePtr = RegInfo->getFrameRegister(MF); @@ -977,7 +1016,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, unsigned Opc = PI->getOpcode(); if (Opc != X86::POP32r && Opc != X86::POP64r && Opc != X86::DBG_VALUE && - !PI->getDesc().isTerminator()) + !PI->isTerminator()) break; --MBBI; @@ -997,7 +1036,8 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, // We cannot use LEA here, because stack pointer was realigned. We need to // deallocate local frame back. if (CSSize) { - emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, UseLEA, TII, + *RegInfo); MBBI = prior(LastCSPop); } @@ -1018,7 +1058,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF, } } else if (NumBytes) { // Adjust stack pointer back: ESP += numbytes. - emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, UseLEA, TII, *RegInfo); } // We're returning from function via eh_return. @@ -1053,7 +1093,7 @@ 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, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, UseLEA, TII, *RegInfo); } // Jump to label or value in register. @@ -1097,7 +1137,7 @@ 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, TII, *RegInfo); + emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, UseLEA, TII, *RegInfo); } } @@ -1280,31 +1320,35 @@ 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. static unsigned -GetScratchRegister(bool Is64Bit, const MachineFunction &MF) { - if (Is64Bit) { - return X86::R11; - } else { - CallingConv::ID CallingConvention = MF.getFunction()->getCallingConv(); - bool IsNested = HasNestArgument(&MF); - - if (CallingConvention == CallingConv::X86_FastCall) { - if (IsNested) { - report_fatal_error("Segmented stacks does not support fastcall with " - "nested function."); - return -1; - } else { - return X86::EAX; - } - } else { - if (IsNested) - return X86::EDX; - else - return X86::ECX; - } +GetScratchRegister(bool Is64Bit, const MachineFunction &MF, bool Primary) { + if (Is64Bit) + return Primary ? X86::R11 : X86::R12; + + CallingConv::ID CallingConvention = MF.getFunction()->getCallingConv(); + bool IsNested = HasNestArgument(&MF); + + if (CallingConvention == CallingConv::X86_FastCall || + CallingConvention == CallingConv::Fast) { + if (IsNested) + report_fatal_error("Segmented stacks does not support fastcall with " + "nested function."); + return Primary ? X86::EAX : X86::ECX; } + if (IsNested) + return Primary ? X86::EDX : X86::EAX; + return Primary ? X86::ECX : X86::EAX; } +// The stack limit in the TCB is set to this many bytes above the actual stack +// limit. +static const uint64_t kSplitStackAvailable = 256; + void X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { MachineBasicBlock &prologueMBB = MF.front(); @@ -1316,14 +1360,15 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { DebugLoc DL; const X86Subtarget *ST = &MF.getTarget().getSubtarget<X86Subtarget>(); - unsigned ScratchReg = GetScratchRegister(Is64Bit, MF); + unsigned ScratchReg = GetScratchRegister(Is64Bit, MF, true); assert(!MF.getRegInfo().isLiveIn(ScratchReg) && "Scratch register is live-in"); if (MF.getFunction()->isVarArg()) report_fatal_error("Segmented stacks do not support vararg functions."); - if (!ST->isTargetLinux()) - report_fatal_error("Segmented stacks supported only on linux."); + if (!ST->isTargetLinux() && !ST->isTargetDarwin() && + !ST->isTargetWin32() && !ST->isTargetFreeBSD()) + report_fatal_error("Segmented stacks not supported on this platform."); MachineBasicBlock *allocMBB = MF.CreateMachineBasicBlock(); MachineBasicBlock *checkMBB = MF.CreateMachineBasicBlock(); @@ -1336,26 +1381,16 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { // The MOV R10, RAX needs to be in a different block, since the RET we emit in // allocMBB needs to be last (terminating) instruction. - MachineBasicBlock *restoreR10MBB = NULL; - if (IsNested) - restoreR10MBB = MF.CreateMachineBasicBlock(); for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(), e = prologueMBB.livein_end(); i != e; i++) { allocMBB->addLiveIn(*i); checkMBB->addLiveIn(*i); - - if (IsNested) - restoreR10MBB->addLiveIn(*i); } - if (IsNested) { + if (IsNested) allocMBB->addLiveIn(X86::R10); - restoreR10MBB->addLiveIn(X86::RAX); - } - if (IsNested) - MF.push_front(restoreR10MBB); MF.push_front(allocMBB); MF.push_front(checkMBB); @@ -1364,28 +1399,99 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { // prologue. StackSize = MFI->getStackSize(); + // 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 = StackSize < kSplitStackAvailable; + // Read the limit off the current stacklet off the stack_guard location. if (Is64Bit) { - TlsReg = X86::FS; - TlsOffset = 0x70; + if (ST->isTargetLinux()) { + TlsReg = X86::FS; + TlsOffset = 0x70; + } else if (ST->isTargetDarwin()) { + TlsReg = X86::GS; + TlsOffset = 0x60 + 90*8; // See pthread_machdep.h. Steal TLS slot 90. + } else if (ST->isTargetFreeBSD()) { + TlsReg = X86::FS; + TlsOffset = 0x18; + } else { + report_fatal_error("Segmented stacks not supported on this platform."); + } + + if (CompareStackPointer) + ScratchReg = X86::RSP; + else + BuildMI(checkMBB, DL, TII.get(X86::LEA64r), ScratchReg).addReg(X86::RSP) + .addImm(1).addReg(0).addImm(-StackSize).addReg(0); - BuildMI(checkMBB, DL, TII.get(X86::LEA64r), ScratchReg).addReg(X86::RSP) - .addImm(0).addReg(0).addImm(-StackSize).addReg(0); BuildMI(checkMBB, DL, TII.get(X86::CMP64rm)).addReg(ScratchReg) - .addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg); + .addReg(0).addImm(1).addReg(0).addImm(TlsOffset).addReg(TlsReg); } else { - TlsReg = X86::GS; - TlsOffset = 0x30; + if (ST->isTargetLinux()) { + TlsReg = X86::GS; + TlsOffset = 0x30; + } else if (ST->isTargetDarwin()) { + TlsReg = X86::GS; + TlsOffset = 0x48 + 90*4; + } else if (ST->isTargetWin32()) { + TlsReg = X86::FS; + TlsOffset = 0x14; // pvArbitrary, reserved for application use + } else if (ST->isTargetFreeBSD()) { + report_fatal_error("Segmented stacks not supported on FreeBSD i386."); + } else { + report_fatal_error("Segmented stacks not supported on this platform."); + } + + if (CompareStackPointer) + ScratchReg = X86::ESP; + else + BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP) + .addImm(1).addReg(0).addImm(-StackSize).addReg(0); + + if (ST->isTargetLinux() || ST->isTargetWin32()) { + BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)).addReg(ScratchReg) + .addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg); + } else if (ST->isTargetDarwin()) { + + // TlsOffset doesn't fit into a mod r/m byte so we need an extra register + unsigned ScratchReg2; + bool SaveScratch2; + if (CompareStackPointer) { + // The primary scratch register is available for holding the TLS offset + ScratchReg2 = GetScratchRegister(Is64Bit, MF, true); + SaveScratch2 = false; + } else { + // Need to use a second register to hold the TLS offset + ScratchReg2 = GetScratchRegister(Is64Bit, MF, false); + + // Unfortunately, with fastcc the second scratch register may hold an arg + SaveScratch2 = MF.getRegInfo().isLiveIn(ScratchReg2); + } - BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP) - .addImm(0).addReg(0).addImm(-StackSize).addReg(0); - BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)).addReg(ScratchReg) - .addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg); + // If Scratch2 is live-in then it needs to be saved + assert((!MF.getRegInfo().isLiveIn(ScratchReg2) || SaveScratch2) && + "Scratch register is live-in and not saved"); + + if (SaveScratch2) + BuildMI(checkMBB, DL, TII.get(X86::PUSH32r)) + .addReg(ScratchReg2, RegState::Kill); + + BuildMI(checkMBB, DL, TII.get(X86::MOV32ri), ScratchReg2) + .addImm(TlsOffset); + BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)) + .addReg(ScratchReg) + .addReg(ScratchReg2).addImm(1).addReg(0) + .addImm(0) + .addReg(TlsReg); + + if (SaveScratch2) + BuildMI(checkMBB, DL, TII.get(X86::POP32r), ScratchReg2); + } } // This jump is taken if SP >= (Stacklet Limit + Stack Space required). // It jumps to normal execution of the function body. - BuildMI(checkMBB, DL, TII.get(X86::JG_4)).addMBB(&prologueMBB); + BuildMI(checkMBB, DL, TII.get(X86::JA_4)).addMBB(&prologueMBB); // On 32 bit we first push the arguments size and then the frame size. On 64 // bit, we pass the stack frame size in r10 and the argument size in r11. @@ -1403,9 +1509,6 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { MF.getRegInfo().setPhysRegUsed(X86::R10); MF.getRegInfo().setPhysRegUsed(X86::R11); } else { - // Since we'll call __morestack, stack alignment needs to be preserved. - BuildMI(allocMBB, DL, TII.get(X86::SUB32ri), X86::ESP).addReg(X86::ESP) - .addImm(8); BuildMI(allocMBB, DL, TII.get(X86::PUSHi32)) .addImm(X86FI->getArgumentStackSize()); BuildMI(allocMBB, DL, TII.get(X86::PUSHi32)) @@ -1420,23 +1523,12 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { BuildMI(allocMBB, DL, TII.get(X86::CALLpcrel32)) .addExternalSymbol("__morestack"); - // __morestack only seems to remove 8 bytes off the stack. Add back the - // additional 8 bytes we added before pushing the arguments. - if (!Is64Bit) - BuildMI(allocMBB, DL, TII.get(X86::ADD32ri), X86::ESP).addReg(X86::ESP) - .addImm(8); - BuildMI(allocMBB, DL, TII.get(X86::RET)); - if (IsNested) - BuildMI(restoreR10MBB, DL, TII.get(X86::MOV64rr), X86::R10) - .addReg(X86::RAX); + BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET_RESTORE_R10)); + else + BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET)); - if (IsNested) { - allocMBB->addSuccessor(restoreR10MBB); - restoreR10MBB->addSuccessor(&prologueMBB); - } else { - allocMBB->addSuccessor(&prologueMBB); - } + allocMBB->addSuccessor(&prologueMBB); checkMBB->addSuccessor(allocMBB); checkMBB->addSuccessor(&prologueMBB); |
