diff options
Diffstat (limited to 'contrib/llvm/lib/Target/X86/X86FrameLowering.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/X86/X86FrameLowering.cpp | 337 |
1 files changed, 31 insertions, 306 deletions
diff --git a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp index 42b4e73..a06ba9d 100644 --- a/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/contrib/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -307,12 +307,12 @@ void X86FrameLowering::emitCalleeSavedFrameMoves(MachineFunction &MF, unsigned FramePtr) const { MachineFrameInfo *MFI = MF.getFrameInfo(); MachineModuleInfo &MMI = MF.getMMI(); + const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo(); // Add callee saved registers to move list. const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo(); if (CSI.empty()) return; - std::vector<MachineMove> &Moves = MMI.getFrameMoves(); const X86RegisterInfo *RegInfo = TM.getRegisterInfo(); bool HasFP = hasFP(MF); @@ -360,276 +360,18 @@ void X86FrameLowering::emitCalleeSavedFrameMoves(MachineFunction &MF, if (HasFP && FramePtr == Reg) continue; - MachineLocation CSDst(MachineLocation::VirtualFP, Offset); - MachineLocation CSSrc(Reg); - Moves.push_back(MachineMove(Label, CSDst, CSSrc)); + unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true); + MMI.addFrameInst(MCCFIInstruction::createOffset(Label, DwarfReg, Offset)); } } -/// getCompactUnwindRegNum - Get the compact unwind number for a given -/// register. The number corresponds to the enum lists in -/// compact_unwind_encoding.h. -static int getCompactUnwindRegNum(unsigned Reg, bool is64Bit) { - static const uint16_t CU32BitRegs[] = { - X86::EBX, X86::ECX, X86::EDX, X86::EDI, X86::ESI, X86::EBP, 0 - }; - static const uint16_t CU64BitRegs[] = { - X86::RBX, X86::R12, X86::R13, X86::R14, X86::R15, X86::RBP, 0 - }; - const uint16_t *CURegs = is64Bit ? CU64BitRegs : CU32BitRegs; - 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[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 - // register. E.g., if we have registers {6, 2, 4, 5} saved in that order: - // - // Orig Re-Num - // ---- ------ - // 6 6 - // 2 2 - // 4 3 - // 5 3 - // - for (unsigned i = 0; i != CU_NUM_SAVED_REGS; ++i) { - int CUReg = getCompactUnwindRegNum(SavedRegs[i], Is64Bit); - 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 = CU_NUM_SAVED_REGS - RegCount; j < i; ++j) - if (SavedRegs[j] < SavedRegs[i]) - ++Countless; - - RenumRegs[i] = SavedRegs[i] - Countless - 1; - } - - // Take the renumbered values and encode them into a 10-bit number. - uint32_t permutationEncoding = 0; - switch (RegCount) { - case 6: - permutationEncoding |= 120 * RenumRegs[0] + 24 * RenumRegs[1] - + 6 * RenumRegs[2] + 2 * RenumRegs[3] - + RenumRegs[4]; - break; - case 5: - permutationEncoding |= 120 * RenumRegs[1] + 24 * RenumRegs[2] - + 6 * RenumRegs[3] + 2 * RenumRegs[4] - + RenumRegs[5]; - break; - case 4: - permutationEncoding |= 60 * RenumRegs[2] + 12 * RenumRegs[3] - + 3 * RenumRegs[4] + RenumRegs[5]; - break; - case 3: - permutationEncoding |= 20 * RenumRegs[3] + 4 * RenumRegs[4] - + RenumRegs[5]; - break; - case 2: - permutationEncoding |= 5 * RenumRegs[4] + RenumRegs[5]; - break; - case 1: - permutationEncoding |= RenumRegs[5]; - break; - } - - assert((permutationEncoding & 0x3FF) == permutationEncoding && - "Invalid compact register encoding!"); - return permutationEncoding; -} - -/// encodeCompactUnwindRegistersWithFrame - Return the registers encoded for a -/// compact encoding with a frame pointer. -static uint32_t -encodeCompactUnwindRegistersWithFrame(unsigned SavedRegs[CU_NUM_SAVED_REGS], - bool Is64Bit) { - // Encode the registers in the order they were saved, 3-bits per register. The - // registers are numbered from 1 to CU_NUM_SAVED_REGS. - uint32_t RegEnc = 0; - for (int I = CU_NUM_SAVED_REGS - 1, Idx = 0; I != -1; --I) { - unsigned Reg = SavedRegs[I]; - if (Reg == 0) continue; - - int CURegNum = getCompactUnwindRegNum(Reg, Is64Bit); - 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 & 0x3FFFF) == RegEnc && "Invalid compact register encoding!"); - return RegEnc; -} - -uint32_t X86FrameLowering::getCompactUnwindEncoding(MachineFunction &MF) const { - const X86RegisterInfo *RegInfo = TM.getRegisterInfo(); - unsigned FramePtr = RegInfo->getFrameRegister(MF); - unsigned StackPtr = RegInfo->getStackRegister(); - - bool Is64Bit = STI.is64Bit(); - bool HasFP = hasFP(MF); - - unsigned SavedRegs[CU_NUM_SAVED_REGS] = { 0, 0, 0, 0, 0, 0 }; - unsigned SavedRegIdx = 0; - - unsigned OffsetSize = (Is64Bit ? 8 : 4); - - unsigned PushInstr = (Is64Bit ? X86::PUSH64r : X86::PUSH32r); - unsigned PushInstrSize = 1; - unsigned MoveInstr = (Is64Bit ? X86::MOV64rr : X86::MOV32rr); - unsigned MoveInstrSize = (Is64Bit ? 3 : 2); - unsigned SubtractInstrIdx = (Is64Bit ? 3 : 2); - - unsigned StackDivide = (Is64Bit ? 8 : 4); - - unsigned InstrOffset = 0; - unsigned StackAdjust = 0; - unsigned StackSize = 0; - - MachineBasicBlock &MBB = MF.front(); // Prologue is in entry BB. - bool ExpectEnd = false; - for (MachineBasicBlock::iterator - MBBI = MBB.begin(), MBBE = MBB.end(); MBBI != MBBE; ++MBBI) { - MachineInstr &MI = *MBBI; - unsigned Opc = MI.getOpcode(); - if (Opc == X86::PROLOG_LABEL) continue; - if (!MI.getFlag(MachineInstr::FrameSetup)) break; - - // We don't exect any more prolog instructions. - if (ExpectEnd) return CU::UNWIND_MODE_DWARF; - - if (Opc == PushInstr) { - // If there are too many saved registers, we cannot use compact encoding. - if (SavedRegIdx >= CU_NUM_SAVED_REGS) return CU::UNWIND_MODE_DWARF; - - unsigned Reg = MI.getOperand(0).getReg(); - if (Reg == (Is64Bit ? X86::RAX : X86::EAX)) { - ExpectEnd = true; - continue; - } - - SavedRegs[SavedRegIdx++] = MI.getOperand(0).getReg(); - StackAdjust += OffsetSize; - InstrOffset += PushInstrSize; - } else if (Opc == MoveInstr) { - unsigned SrcReg = MI.getOperand(1).getReg(); - unsigned DstReg = MI.getOperand(0).getReg(); - - if (DstReg != FramePtr || SrcReg != StackPtr) - return CU::UNWIND_MODE_DWARF; - - StackAdjust = 0; - memset(SavedRegs, 0, sizeof(SavedRegs)); - SavedRegIdx = 0; - InstrOffset += MoveInstrSize; - } else if (Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 || - Opc == X86::SUB32ri || Opc == X86::SUB32ri8) { - if (StackSize) - // We already have a stack size. - return CU::UNWIND_MODE_DWARF; - - if (!MI.getOperand(0).isReg() || - MI.getOperand(0).getReg() != MI.getOperand(1).getReg() || - MI.getOperand(0).getReg() != StackPtr || !MI.getOperand(2).isImm()) - // We need this to be a stack adjustment pointer. Something like: - // - // %RSP<def> = SUB64ri8 %RSP, 48 - return CU::UNWIND_MODE_DWARF; - - StackSize = MI.getOperand(2).getImm() / StackDivide; - SubtractInstrIdx += InstrOffset; - ExpectEnd = true; - } - } - - // Encode that we are using EBP/RBP as the frame pointer. - uint32_t CompactUnwindEncoding = 0; - StackAdjust /= StackDivide; - if (HasFP) { - if ((StackAdjust & 0xFF) != StackAdjust) - // Offset was too big for compact encoding. - return CU::UNWIND_MODE_DWARF; - - // Get the encoding of the saved registers when we have a frame pointer. - uint32_t RegEnc = encodeCompactUnwindRegistersWithFrame(SavedRegs, Is64Bit); - if (RegEnc == ~0U) return CU::UNWIND_MODE_DWARF; - - CompactUnwindEncoding |= CU::UNWIND_MODE_BP_FRAME; - CompactUnwindEncoding |= (StackAdjust & 0xFF) << 16; - CompactUnwindEncoding |= RegEnc & CU::UNWIND_BP_FRAME_REGISTERS; - } else { - ++StackAdjust; - uint32_t TotalStackSize = StackAdjust + StackSize; - if ((TotalStackSize & 0xFF) == TotalStackSize) { - // Frameless stack with a small stack size. - CompactUnwindEncoding |= CU::UNWIND_MODE_STACK_IMMD; - - // Encode the stack size. - CompactUnwindEncoding |= (TotalStackSize & 0xFF) << 16; - } else { - if ((StackAdjust & 0x7) != StackAdjust) - // The extra stack adjustments are too big for us to handle. - return CU::UNWIND_MODE_DWARF; - - // Frameless stack with an offset too large for us to encode compactly. - CompactUnwindEncoding |= CU::UNWIND_MODE_STACK_IND; - - // Encode the offset to the nnnnnn value in the 'subl $nnnnnn, ESP' - // instruction. - CompactUnwindEncoding |= (SubtractInstrIdx & 0xFF) << 16; - - // 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, SavedRegIdx, - Is64Bit); - if (RegEnc == ~0U) return CU::UNWIND_MODE_DWARF; - - // Encode the register encoding. - CompactUnwindEncoding |= - RegEnc & CU::UNWIND_FRAMELESS_STACK_REG_PERMUTATION; - } - - 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(); +static bool usesTheStack(const MachineFunction &MF) { + const MachineRegisterInfo &MRI = MF.getRegInfo(); for (MachineRegisterInfo::reg_iterator ri = MRI.reg_begin(X86::EFLAGS), re = MRI.reg_end(); ri != re; ++ri) @@ -732,7 +474,6 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { // REG < 64 => DW_CFA_offset + Reg // ELSE => DW_CFA_offset_extended - std::vector<MachineMove> &Moves = MMI.getFrameMoves(); uint64_t NumBytes = 0; int stackGrowth = -SlotSize; @@ -765,20 +506,14 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { .addSym(FrameLabel); // Define the current CFA rule to use the provided offset. - if (StackSize) { - MachineLocation SPDst(MachineLocation::VirtualFP); - MachineLocation SPSrc(MachineLocation::VirtualFP, 2 * stackGrowth); - Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc)); - } else { - MachineLocation SPDst(StackPtr); - MachineLocation SPSrc(StackPtr, stackGrowth); - Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc)); - } + assert(StackSize); + MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(FrameLabel, 2 * stackGrowth)); // Change the rule for the FramePtr to be an "offset" rule. - MachineLocation FPDst(MachineLocation::VirtualFP, 2 * stackGrowth); - MachineLocation FPSrc(FramePtr); - Moves.push_back(MachineMove(FrameLabel, FPDst, FPSrc)); + unsigned DwarfFramePtr = RegInfo->getDwarfRegNum(FramePtr, true); + MMI.addFrameInst(MCCFIInstruction::createOffset(FrameLabel, DwarfFramePtr, + 2 * stackGrowth)); } // Update EBP with the new base value. @@ -794,9 +529,9 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { .addSym(FrameLabel); // Define the current CFA to use the EBP/RBP register. - MachineLocation FPDst(FramePtr); - MachineLocation FPSrc(MachineLocation::VirtualFP); - Moves.push_back(MachineMove(FrameLabel, FPDst, FPSrc)); + unsigned DwarfFramePtr = RegInfo->getDwarfRegNum(FramePtr, true); + MMI.addFrameInst( + MCCFIInstruction::createDefCfaRegister(FrameLabel, DwarfFramePtr)); } // Mark the FramePtr as live-in in every block except the entry. @@ -824,10 +559,9 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { BuildMI(MBB, MBBI, DL, TII.get(X86::PROLOG_LABEL)).addSym(Label); // Define the current CFA rule to use the provided offset. - unsigned Ptr = StackSize ? MachineLocation::VirtualFP : StackPtr; - MachineLocation SPDst(Ptr); - MachineLocation SPSrc(Ptr, StackOffset); - Moves.push_back(MachineMove(Label, SPDst, SPSrc)); + assert(StackSize); + MMI.addFrameInst( + MCCFIInstruction::createDefCfaOffset(Label, StackOffset)); StackOffset += stackGrowth; } } @@ -872,7 +606,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { // responsible for adjusting the stack pointer. Touching the stack at 4K // increments is necessary to ensure that the guard pages used by the OS // virtual memory manager are allocated in correct sequence. - if (NumBytes >= 4096 && STI.isTargetCOFF() && !STI.isTargetEnvMacho()) { + if (NumBytes >= 4096 && STI.isOSWindows() && !STI.isTargetEnvMacho()) { const char *StackProbeSymbol; bool isSPUpdateNeeded = false; @@ -923,11 +657,14 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit) .setMIFlag(MachineInstr::FrameSetup); - // 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, IsLP64, - UseLEA, TII, *RegInfo); + // MSVC x64's __chkstk does not adjust %rsp itself. + // It also does not clobber %rax so we can reuse it when adjusting %rsp. + if (isSPUpdateNeeded) { + BuildMI(MBB, MBBI, DL, TII.get(X86::SUB64rr), StackPtr) + .addReg(StackPtr) + .addReg(X86::RAX) + .setMIFlag(MachineInstr::FrameSetup); + } if (isEAXAlive) { // Restore EAX @@ -961,27 +698,15 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const { if (!HasFP && NumBytes) { // Define the current CFA rule to use the provided offset. - if (StackSize) { - MachineLocation SPDst(MachineLocation::VirtualFP); - MachineLocation SPSrc(MachineLocation::VirtualFP, - -StackSize + stackGrowth); - Moves.push_back(MachineMove(Label, SPDst, SPSrc)); - } else { - MachineLocation SPDst(StackPtr); - MachineLocation SPSrc(StackPtr, stackGrowth); - Moves.push_back(MachineMove(Label, SPDst, SPSrc)); - } + assert(StackSize); + MMI.addFrameInst(MCCFIInstruction::createDefCfaOffset( + Label, -StackSize + stackGrowth)); } // Emit DWARF info specifying the offsets of the callee-saved registers. if (PushedRegs) emitCalleeSavedFrameMoves(MF, Label, HasFP ? FramePtr : StackPtr); } - - // Darwin 10.7 and greater has support for compact unwind encoding. - if (STI.getTargetTriple().isMacOSX() && - !STI.getTargetTriple().isMacOSXVersionLT(10, 7)) - MMI.setCompactUnwindEncoding(getCompactUnwindEncoding(MF)); } void X86FrameLowering::emitEpilogue(MachineFunction &MF, @@ -1336,7 +1061,7 @@ X86FrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, unsigned SlotSize = RegInfo->getSlotSize(); X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>(); - int32_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta(); + int64_t TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta(); if (TailCallReturnAddrDelta < 0) { // create RETURNADDR area @@ -1349,7 +1074,7 @@ X86FrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF, // } // [EBP] MFI->CreateFixedObject(-TailCallReturnAddrDelta, - (-1U*SlotSize)+TailCallReturnAddrDelta, true); + TailCallReturnAddrDelta - SlotSize, true); } if (hasFP(MF)) { |
