extern cl::opt<bool> ForceStackAlign;
bool X86FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
- return !MF.getFrameInfo()->hasVarSizedObjects();
+ return !MF.getFrameInfo()->hasVarSizedObjects() &&
+ !MF.getInfo<X86MachineFunctionInfo>()->getHasPushSequences();
+}
+
+/// canSimplifyCallFramePseudos - If there is a reserved call frame, the
+/// call frame pseudos can be simplified. Having a FP, as in the default
+/// implementation, is not sufficient here since we can't always use it.
+/// Use a more nuanced condition.
+bool
+X86FrameLowering::canSimplifyCallFramePseudos(const MachineFunction &MF) const {
+ const X86RegisterInfo *TRI = static_cast<const X86RegisterInfo *>
+ (MF.getSubtarget().getRegisterInfo());
+ return hasReservedCallFrame(MF) ||
+ (hasFP(MF) && !TRI->needsStackRealignment(MF))
+ || TRI->hasBasePointer(MF);
+}
+
+// needsFrameIndexResolution - Do we need to perform FI resolution for
+// this function. Normally, this is required only when the function
+// has any stack objects. However, FI resolution actually has another job,
+// not apparent from the title - it resolves callframesetup/destroy
+// that were not simplified earlier.
+// So, this is required for x86 functions that have push sequences even
+// when there are no stack objects.
+bool
+X86FrameLowering::needsFrameIndexResolution(const MachineFunction &MF) const {
+ return MF.getFrameInfo()->hasStackObjects() ||
+ MF.getInfo<X86MachineFunctionInfo>()->getHasPushSequences();
}
/// hasFP - Return true if the specified function should have a dedicated frame
}
}
+static unsigned getSUBrrOpcode(unsigned isLP64) {
+ return isLP64 ? X86::SUB64rr : X86::SUB32rr;
+}
+
+static unsigned getADDrrOpcode(unsigned isLP64) {
+ return isLP64 ? X86::ADD64rr : X86::ADD32rr;
+}
+
static unsigned getANDriOpcode(bool IsLP64, int64_t Imm) {
if (IsLP64) {
if (isInt<8>(Imm))
return 0;
}
+static bool isEAXLiveIn(MachineFunction &MF) {
+ for (MachineRegisterInfo::livein_iterator II = MF.getRegInfo().livein_begin(),
+ EE = MF.getRegInfo().livein_end(); II != EE; ++II) {
+ unsigned Reg = II->first;
+
+ if (Reg == X86::RAX || Reg == X86::EAX || Reg == X86::AX ||
+ Reg == X86::AH || Reg == X86::AL)
+ return true;
+ }
+
+ return false;
+}
/// emitSPUpdate - Emit a series of instructions to increment / decrement the
/// stack pointer by a constant value.
-static
-void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
- unsigned StackPtr, int64_t NumBytes,
- bool Is64BitTarget, bool Is64BitStackPtr, bool UseLEA,
- const TargetInstrInfo &TII, const TargetRegisterInfo &TRI) {
+void X86FrameLowering::emitSPUpdate(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ unsigned StackPtr, int64_t NumBytes,
+ bool Is64BitTarget, bool Is64BitStackPtr,
+ bool UseLEA, const TargetInstrInfo &TII,
+ const TargetRegisterInfo &TRI) {
bool isSub = NumBytes < 0;
uint64_t Offset = isSub ? -NumBytes : NumBytes;
unsigned Opc;
DebugLoc DL = MBB.findDebugLoc(MBBI);
while (Offset) {
- uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
+ if (Offset > Chunk) {
+ // Rather than emit a long series of instructions for large offsets,
+ // load the offset into a register and do one sub/add
+ unsigned Reg = 0;
+
+ if (isSub && !isEAXLiveIn(*MBB.getParent()))
+ Reg = (unsigned)(Is64BitTarget ? X86::RAX : X86::EAX);
+ else
+ Reg = findDeadCallerSavedReg(MBB, MBBI, TRI, Is64BitTarget);
+
+ if (Reg) {
+ Opc = Is64BitTarget ? X86::MOV64ri : X86::MOV32ri;
+ BuildMI(MBB, MBBI, DL, TII.get(Opc), Reg)
+ .addImm(Offset);
+ Opc = isSub
+ ? getSUBrrOpcode(Is64BitTarget)
+ : getADDrrOpcode(Is64BitTarget);
+ MachineInstr *MI = BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr)
+ .addReg(StackPtr)
+ .addReg(Reg);
+ MI->getOperand(3).setIsDead(); // The EFLAGS implicit def is dead.
+ Offset = 0;
+ continue;
+ }
+ }
+
+ uint64_t ThisVal = std::min(Offset, Chunk);
if (ThisVal == (Is64BitTarget ? 8 : 4)) {
// Use push / pop instead.
unsigned Reg = isSub
}
}
-/// mergeSPUpdatesDown - Merge two stack-manipulating instructions lower
-/// iterator.
-static
-void mergeSPUpdatesDown(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MBBI,
- unsigned StackPtr, uint64_t *NumBytes = nullptr) {
- // FIXME: THIS ISN'T RUN!!!
- return;
-
- if (MBBI == MBB.end()) return;
-
- MachineBasicBlock::iterator NI = std::next(MBBI);
- if (NI == MBB.end()) return;
-
- unsigned Opc = NI->getOpcode();
- if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 ||
- Opc == X86::ADD32ri || Opc == X86::ADD32ri8) &&
- NI->getOperand(0).getReg() == StackPtr) {
- if (NumBytes)
- *NumBytes -= NI->getOperand(2).getImm();
- MBB.erase(NI);
- MBBI = NI;
- } else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 ||
- Opc == X86::SUB32ri || Opc == X86::SUB32ri8) &&
- NI->getOperand(0).getReg() == StackPtr) {
- if (NumBytes)
- *NumBytes += NI->getOperand(2).getImm();
- MBB.erase(NI);
- MBBI = NI;
- }
-}
-
-/// mergeSPUpdates - Checks the instruction before/after the passed
-/// 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, unsigned StackPtr,
- bool doMergeWithPrevious) {
+int X86FrameLowering::mergeSPUpdates(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ unsigned StackPtr,
+ bool doMergeWithPrevious) {
if ((doMergeWithPrevious && MBBI == MBB.begin()) ||
(!doMergeWithPrevious && MBBI == MBB.end()))
return 0;
return Offset;
}
-static bool isEAXLiveIn(MachineFunction &MF) {
- for (MachineRegisterInfo::livein_iterator II = MF.getRegInfo().livein_begin(),
- EE = MF.getRegInfo().livein_end(); II != EE; ++II) {
- unsigned Reg = II->first;
-
- if (Reg == X86::EAX || Reg == X86::AX ||
- Reg == X86::AH || Reg == X86::AL)
- return true;
- }
-
- return false;
+/// Wraps up getting a CFI index and building a MachineInstr for it.
+static void BuildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
+ DebugLoc DL, const TargetInstrInfo &TII,
+ MCCFIInstruction CFIInst) {
+ MachineFunction &MF = *MBB.getParent();
+ unsigned CFIIndex = MF.getMMI().addFrameInst(CFIInst);
+ BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
+ .addCFIIndex(CFIIndex);
}
void
unsigned Reg = I->getReg();
unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true);
- unsigned CFIIndex =
- MMI.addFrameInst(MCCFIInstruction::createOffset(nullptr, DwarfReg,
- Offset));
- BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
- .addCFIIndex(CFIIndex);
+ BuildCFI(MBB, MBBI, DL, TII,
+ MCCFIInstruction::createOffset(nullptr, DwarfReg, Offset));
}
}
return false;
}
-void X86FrameLowering::getStackProbeFunction(const X86Subtarget &STI,
- unsigned &CallOp,
- const char *&Symbol) {
- CallOp = STI.is64Bit() ? X86::W64ALLOCA : X86::CALLpcrel32;
+void X86FrameLowering::emitStackProbeCall(MachineFunction &MF,
+ MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MBBI,
+ DebugLoc DL) {
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
+ bool Is64Bit = STI.is64Bit();
+ bool IsLargeCodeModel = MF.getTarget().getCodeModel() == CodeModel::Large;
- if (STI.is64Bit()) {
+ unsigned CallOp;
+ if (Is64Bit)
+ CallOp = IsLargeCodeModel ? X86::CALL64r : X86::CALL64pcrel32;
+ else
+ CallOp = X86::CALLpcrel32;
+
+ const char *Symbol;
+ if (Is64Bit) {
if (STI.isTargetCygMing()) {
Symbol = "___chkstk_ms";
} else {
Symbol = "_alloca";
else
Symbol = "_chkstk";
+
+ MachineInstrBuilder CI;
+
+ // All current stack probes take AX and SP as input, clobber flags, and
+ // preserve all registers. x86_64 probes leave RSP unmodified.
+ if (Is64Bit && MF.getTarget().getCodeModel() == CodeModel::Large) {
+ // For the large code model, we have to call through a register. Use R11,
+ // as it is scratch in all supported calling conventions.
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri), X86::R11)
+ .addExternalSymbol(Symbol);
+ CI = BuildMI(MBB, MBBI, DL, TII.get(CallOp)).addReg(X86::R11);
+ } else {
+ CI = BuildMI(MBB, MBBI, DL, TII.get(CallOp)).addExternalSymbol(Symbol);
+ }
+
+ unsigned AX = Is64Bit ? X86::RAX : X86::EAX;
+ unsigned SP = Is64Bit ? X86::RSP : X86::ESP;
+ CI.addReg(AX, RegState::Implicit)
+ .addReg(SP, RegState::Implicit)
+ .addReg(AX, RegState::Define | RegState::Implicit)
+ .addReg(SP, RegState::Define | RegState::Implicit)
+ .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit);
+
+ if (Is64Bit) {
+ // MSVC x64's __chkstk and cygwin/mingw's ___chkstk_ms do not adjust %rsp
+ // themselves. It also does not clobber %rax so we can reuse it when
+ // adjusting %rsp.
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SUB64rr), X86::RSP)
+ .addReg(X86::RSP)
+ .addReg(X86::RAX);
+ }
+}
+
+static unsigned calculateSetFPREG(uint64_t SPAdjust) {
+ // Win64 ABI has a less restrictive limitation of 240; 128 works equally well
+ // and might require smaller successive adjustments.
+ const uint64_t Win64MaxSEHOffset = 128;
+ uint64_t SEHFrameOffset = std::min(SPAdjust, Win64MaxSEHOffset);
+ // Win64 ABI requires 16-byte alignment for the UWOP_SET_FPREG opcode.
+ return SEHFrameOffset & -16;
+}
+
+// If we're forcing a stack realignment we can't rely on just the frame
+// info, we need to know the ABI stack alignment as well in case we
+// have a call out. Otherwise just make sure we have some alignment - we'll
+// go with the minimum SlotSize.
+static uint64_t calculateMaxStackAlign(const MachineFunction &MF) {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const X86RegisterInfo *RegInfo = STI.getRegisterInfo();
+ unsigned SlotSize = RegInfo->getSlotSize();
+ unsigned StackAlign = STI.getFrameLowering()->getStackAlignment();
+ if (ForceStackAlign) {
+ if (MFI->hasCalls())
+ MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
+ else if (MaxAlign < SlotSize)
+ MaxAlign = SlotSize;
+ }
+ return MaxAlign;
}
/// emitPrologue - Push callee-saved registers onto the stack, which
- for 32-bit code, substitute %e?? registers for %r??
*/
-void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
- MachineBasicBlock &MBB = MF.front(); // Prologue goes in entry BB.
+void X86FrameLowering::emitPrologue(MachineFunction &MF,
+ MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineFrameInfo *MFI = MF.getFrameInfo();
const Function *Fn = MF.getFunction();
- const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo());
- const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const X86RegisterInfo *RegInfo = STI.getRegisterInfo();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
MachineModuleInfo &MMI = MF.getMMI();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
- uint64_t MaxAlign = MFI->getMaxAlignment(); // Desired stack alignment.
+ uint64_t MaxAlign = calculateMaxStackAlign(MF); // Desired stack alignment.
uint64_t StackSize = MFI->getStackSize(); // Number of bytes to allocate.
bool HasFP = hasFP(MF);
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
bool Is64Bit = STI.is64Bit();
// standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
const bool Uses64BitFramePtr = STI.isTarget64BitLP64() || STI.isTargetNaCl64();
- bool IsWin64 = STI.isTargetWin64();
- // Not necessarily synonymous with IsWin64.
- bool IsWinEH = MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() ==
- ExceptionHandling::ItaniumWinEH;
- bool NeedsWinEH = IsWinEH && Fn->needsUnwindTableEntry();
+ bool IsWin64CC = STI.isCallingConvWin64(Fn->getCallingConv());
+ // Not necessarily synonymous with IsWin64CC.
+ bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ bool NeedsWinCFI = IsWin64Prologue && Fn->needsUnwindTableEntry();
bool NeedsDwarfCFI =
- !IsWinEH && (MMI.hasDebugInfo() || Fn->needsUnwindTableEntry());
+ !IsWin64Prologue && (MMI.hasDebugInfo() || Fn->needsUnwindTableEntry());
bool UseLEA = STI.useLeaForSP();
- unsigned StackAlign = getStackAlignment();
unsigned SlotSize = RegInfo->getSlotSize();
unsigned FramePtr = RegInfo->getFrameRegister(MF);
- const unsigned MachineFramePtr = STI.isTarget64BitILP32() ?
- getX86SubSuperRegister(FramePtr, MVT::i64, false) : FramePtr;
+ const unsigned MachineFramePtr =
+ STI.isTarget64BitILP32()
+ ? getX86SubSuperRegister(FramePtr, MVT::i64, false)
+ : FramePtr;
unsigned StackPtr = RegInfo->getStackRegister();
unsigned BasePtr = RegInfo->getBaseRegister();
DebugLoc DL;
- // If we're forcing a stack realignment we can't rely on just the frame
- // info, we need to know the ABI stack alignment as well in case we
- // have a call out. Otherwise just make sure we have some alignment - we'll
- // go with the minimum SlotSize.
- if (ForceStackAlign) {
- if (MFI->hasCalls())
- MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
- else if (MaxAlign < SlotSize)
- MaxAlign = SlotSize;
- }
-
// Add RETADDR move area to callee saved frame size.
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
+ if (TailCallReturnAddrDelta && IsWin64Prologue)
+ report_fatal_error("Can't handle guaranteed tail call under win64 yet");
+
if (TailCallReturnAddrDelta < 0)
X86FI->setCalleeSavedFrameSize(
X86FI->getCalleeSavedFrameSize() - TailCallReturnAddrDelta);
- bool UseStackProbe = (STI.isOSWindows() && !STI.isTargetMacho());
-
+ bool UseStackProbe = (STI.isOSWindows() && !STI.isTargetMachO());
+
+ // The default stack probe size is 4096 if the function has no stackprobesize
+ // attribute.
+ unsigned StackProbeSize = 4096;
+ if (Fn->hasFnAttribute("stack-probe-size"))
+ Fn->getFnAttribute("stack-probe-size")
+ .getValueAsString()
+ .getAsInteger(0, StackProbeSize);
+
// 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). We also check that we don't
// push and pop from the stack.
- if (Is64Bit && !Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
- Attribute::NoRedZone) &&
+ if (Is64Bit && !Fn->hasFnAttribute(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.shouldSplitStack()) { // Regular stack
+ !MFI->hasVarSizedObjects() && // No dynamic alloca.
+ !MFI->adjustsStack() && // No calls.
+ !IsWin64CC && // Win64 has no Red Zone
+ !usesTheStack(MF) && // Don't push and pop.
+ !MF.shouldSplitStack()) { // Regular stack
uint64_t MinSize = X86FI->getCalleeSavedFrameSize();
if (HasFP) MinSize += SlotSize;
StackSize = std::max(MinSize, StackSize > 128 ? StackSize - 128 : 0);
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
// If required, include space for extra hidden slot for stashing base pointer.
- if (X86FI->getRestoreBasePointer())
+ if (X86FI->getRestoreBasePointer())
FrameSize += SlotSize;
- if (RegInfo->needsStackRealignment(MF)) {
- // Callee-saved registers are pushed on stack before the stack
- // is realigned.
- FrameSize -= X86FI->getCalleeSavedFrameSize();
- NumBytes = (FrameSize + MaxAlign - 1) / MaxAlign * MaxAlign;
- } else {
- NumBytes = FrameSize - X86FI->getCalleeSavedFrameSize();
- }
+
+ NumBytes = FrameSize - X86FI->getCalleeSavedFrameSize();
+
+ // Callee-saved registers are pushed on stack before the stack is realigned.
+ if (RegInfo->needsStackRealignment(MF) && !IsWin64Prologue)
+ NumBytes = RoundUpToAlignment(NumBytes, MaxAlign);
// Get the offset of the stack slot for the EBP register, which is
// guaranteed to be the last slot by processFunctionBeforeFrameFinalized.
// Mark the place where EBP/RBP was saved.
// Define the current CFA rule to use the provided offset.
assert(StackSize);
- unsigned CFIIndex = MMI.addFrameInst(
- MCCFIInstruction::createDefCfaOffset(nullptr, 2 * stackGrowth));
- BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
- .addCFIIndex(CFIIndex);
+ BuildCFI(MBB, MBBI, DL, TII,
+ MCCFIInstruction::createDefCfaOffset(nullptr, 2 * stackGrowth));
// Change the rule for the FramePtr to be an "offset" rule.
unsigned DwarfFramePtr = RegInfo->getDwarfRegNum(MachineFramePtr, true);
- CFIIndex = MMI.addFrameInst(
- MCCFIInstruction::createOffset(nullptr,
- DwarfFramePtr, 2 * stackGrowth));
- BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
- .addCFIIndex(CFIIndex);
+ BuildCFI(MBB, MBBI, DL, TII,
+ MCCFIInstruction::createOffset(nullptr, DwarfFramePtr,
+ 2 * stackGrowth));
}
- if (NeedsWinEH) {
+ if (NeedsWinCFI) {
BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_PushReg))
.addImm(FramePtr)
.setMIFlag(MachineInstr::FrameSetup);
}
- // Update EBP with the new base value.
- BuildMI(MBB, MBBI, DL,
- TII.get(Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr), FramePtr)
- .addReg(StackPtr)
- .setMIFlag(MachineInstr::FrameSetup);
+ if (!IsWin64Prologue) {
+ // Update EBP with the new base value.
+ BuildMI(MBB, MBBI, DL,
+ TII.get(Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr),
+ FramePtr)
+ .addReg(StackPtr)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
if (NeedsDwarfCFI) {
// Mark effective beginning of when frame pointer becomes valid.
// Define the current CFA to use the EBP/RBP register.
unsigned DwarfFramePtr = RegInfo->getDwarfRegNum(MachineFramePtr, true);
- unsigned CFIIndex = MMI.addFrameInst(
- MCCFIInstruction::createDefCfaRegister(nullptr, DwarfFramePtr));
- BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
- .addCFIIndex(CFIIndex);
+ BuildCFI(MBB, MBBI, DL, TII,
+ MCCFIInstruction::createDefCfaRegister(nullptr, DwarfFramePtr));
}
// Mark the FramePtr as live-in in every block.
// Mark callee-saved push instruction.
// Define the current CFA rule to use the provided offset.
assert(StackSize);
- unsigned CFIIndex = MMI.addFrameInst(
- MCCFIInstruction::createDefCfaOffset(nullptr, StackOffset));
- BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
- .addCFIIndex(CFIIndex);
+ BuildCFI(MBB, MBBI, DL, TII,
+ MCCFIInstruction::createDefCfaOffset(nullptr, StackOffset));
StackOffset += stackGrowth;
}
- if (NeedsWinEH) {
+ if (NeedsWinCFI) {
BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_PushReg)).addImm(Reg).setMIFlag(
MachineInstr::FrameSetup);
}
// Realign stack after we pushed callee-saved registers (so that we'll be
// able to calculate their offsets from the frame pointer).
- if (RegInfo->needsStackRealignment(MF)) {
+ // Don't do this for Win64, it needs to realign the stack after the prologue.
+ if (!IsWin64Prologue && RegInfo->needsStackRealignment(MF)) {
assert(HasFP && "There should be a frame pointer if stack is realigned.");
uint64_t Val = -MaxAlign;
MachineInstr *MI =
- BuildMI(MBB, MBBI, DL,
- TII.get(getANDriOpcode(Uses64BitFramePtr, Val)), StackPtr)
- .addReg(StackPtr)
- .addImm(Val)
- .setMIFlag(MachineInstr::FrameSetup);
+ BuildMI(MBB, MBBI, DL, TII.get(getANDriOpcode(Uses64BitFramePtr, Val)),
+ StackPtr)
+ .addReg(StackPtr)
+ .addImm(Val)
+ .setMIFlag(MachineInstr::FrameSetup);
// The EFLAGS implicit def is dead.
MI->getOperand(3).setIsDead();
// the callee has more arguments then the caller.
NumBytes -= mergeSPUpdates(MBB, MBBI, StackPtr, true);
- // If there is an ADD32ri or SUB32ri of ESP immediately after this
- // instruction, merge the two instructions.
- mergeSPUpdatesDown(MBB, MBBI, StackPtr, &NumBytes);
-
// Adjust stack pointer: ESP -= numbytes.
- static const size_t PageSize = 4096;
-
// Windows and cygwin/mingw require a prologue helper routine when allocating
// more than 4K bytes on the stack. Windows uses __chkstk and cygwin/mingw
// uses __alloca. __alloca and the 32-bit version of __chkstk will probe the
// 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 >= PageSize && UseStackProbe) {
- const char *StackProbeSymbol;
- unsigned CallOp;
-
- getStackProbeFunction(STI, CallOp, StackProbeSymbol);
-
+ uint64_t AlignedNumBytes = NumBytes;
+ if (IsWin64Prologue && RegInfo->needsStackRealignment(MF))
+ AlignedNumBytes = RoundUpToAlignment(AlignedNumBytes, MaxAlign);
+ if (AlignedNumBytes >= StackProbeSize && UseStackProbe) {
// Check whether EAX is livein for this function.
bool isEAXAlive = isEAXLiveIn(MF);
if (Is64Bit) {
// Handle the 64-bit Windows ABI case where we need to call __chkstk.
// Function prologue is responsible for adjusting the stack pointer.
- BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri), X86::RAX)
- .addImm(NumBytes)
- .setMIFlag(MachineInstr::FrameSetup);
+ if (isUInt<32>(NumBytes)) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), X86::EAX)
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ } else if (isInt<32>(NumBytes)) {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri32), X86::RAX)
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ } else {
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64ri), X86::RAX)
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
} else {
// Allocate NumBytes-4 bytes on stack in case of isEAXAlive.
// We'll also use 4 already allocated bytes for EAX.
.setMIFlag(MachineInstr::FrameSetup);
}
- BuildMI(MBB, MBBI, DL,
- TII.get(CallOp))
- .addExternalSymbol(StackProbeSymbol)
- .addReg(StackPtr, RegState::Define | RegState::Implicit)
- .addReg(X86::EFLAGS, RegState::Define | RegState::Implicit)
- .setMIFlag(MachineInstr::FrameSetup);
+ // Save a pointer to the MI where we set AX.
+ MachineBasicBlock::iterator SetRAX = MBBI;
+ --SetRAX;
+
+ // Call __chkstk, __chkstk_ms, or __alloca.
+ emitStackProbeCall(MF, MBB, MBBI, DL);
+
+ // Apply the frame setup flag to all inserted instrs.
+ for (; SetRAX != MBBI; ++SetRAX)
+ SetRAX->setFlag(MachineInstr::FrameSetup);
- if (Is64Bit) {
- // MSVC x64's __chkstk and cygwin/mingw's ___chkstk_ms do not adjust %rsp
- // themself. It also does not clobber %rax so we can reuse it when
- // adjusting %rsp.
- BuildMI(MBB, MBBI, DL, TII.get(X86::SUB64rr), StackPtr)
- .addReg(StackPtr)
- .addReg(X86::RAX)
- .setMIFlag(MachineInstr::FrameSetup);
- }
if (isEAXAlive) {
// Restore EAX
MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),
UseLEA, TII, *RegInfo);
}
+ if (NeedsWinCFI && NumBytes)
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_StackAlloc))
+ .addImm(NumBytes)
+ .setMIFlag(MachineInstr::FrameSetup);
+
int SEHFrameOffset = 0;
- if (NeedsWinEH) {
- if (HasFP) {
- // We need to set frame base offset low enough such that all saved
- // register offsets would be positive relative to it, but we can't
- // just use NumBytes, because .seh_setframe offset must be <=240.
- // So we pretend to have only allocated enough space to spill the
- // non-volatile registers.
- // We don't care about the rest of stack allocation, because unwinder
- // will restore SP to (BP - SEHFrameOffset)
- for (const CalleeSavedInfo &Info : MFI->getCalleeSavedInfo()) {
- int offset = MFI->getObjectOffset(Info.getFrameIdx());
- SEHFrameOffset = std::max(SEHFrameOffset, std::abs(offset));
- }
- SEHFrameOffset += SEHFrameOffset % 16; // ensure alignmant
-
- // This only needs to account for XMM spill slots, GPR slots
- // are covered by the .seh_pushreg's emitted above.
- unsigned Size = SEHFrameOffset - X86FI->getCalleeSavedFrameSize();
- if (Size) {
- BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_StackAlloc))
- .addImm(Size)
- .setMIFlag(MachineInstr::FrameSetup);
- }
+ if (IsWin64Prologue && HasFP) {
+ SEHFrameOffset = calculateSetFPREG(NumBytes);
+ if (SEHFrameOffset)
+ addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::LEA64r), FramePtr),
+ StackPtr, false, SEHFrameOffset);
+ else
+ BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rr), FramePtr).addReg(StackPtr);
+ if (NeedsWinCFI)
BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_SetFrame))
.addImm(FramePtr)
.addImm(SEHFrameOffset)
.setMIFlag(MachineInstr::FrameSetup);
- } else {
- // SP will be the base register for restoring XMMs
- if (NumBytes) {
- BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_StackAlloc))
- .addImm(NumBytes)
- .setMIFlag(MachineInstr::FrameSetup);
- }
- }
}
- // Skip the rest of register spilling code
- while (MBBI != MBB.end() && MBBI->getFlag(MachineInstr::FrameSetup))
+ while (MBBI != MBB.end() && MBBI->getFlag(MachineInstr::FrameSetup)) {
+ const MachineInstr *FrameInstr = &*MBBI;
++MBBI;
- // Emit SEH info for non-GPRs
- if (NeedsWinEH) {
- for (const CalleeSavedInfo &Info : MFI->getCalleeSavedInfo()) {
- unsigned Reg = Info.getReg();
- if (X86::GR64RegClass.contains(Reg) || X86::GR32RegClass.contains(Reg))
- continue;
- assert(X86::FR64RegClass.contains(Reg) && "Unexpected register class");
-
- int Offset = getFrameIndexOffset(MF, Info.getFrameIdx());
- Offset += SEHFrameOffset;
-
- BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_SaveXMM))
- .addImm(Reg)
- .addImm(Offset)
- .setMIFlag(MachineInstr::FrameSetup);
+ if (NeedsWinCFI) {
+ int FI;
+ if (unsigned Reg = TII.isStoreToStackSlot(FrameInstr, FI)) {
+ if (X86::FR64RegClass.contains(Reg)) {
+ int Offset = getFrameIndexOffset(MF, FI);
+ Offset += SEHFrameOffset;
+
+ BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_SaveXMM))
+ .addImm(Reg)
+ .addImm(Offset)
+ .setMIFlag(MachineInstr::FrameSetup);
+ }
+ }
}
+ }
+ if (NeedsWinCFI)
BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_EndPrologue))
.setMIFlag(MachineInstr::FrameSetup);
+
+ // Realign stack after we spilled callee-saved registers (so that we'll be
+ // able to calculate their offsets from the frame pointer).
+ // Win64 requires aligning the stack after the prologue.
+ if (IsWin64Prologue && RegInfo->needsStackRealignment(MF)) {
+ assert(HasFP && "There should be a frame pointer if stack is realigned.");
+ uint64_t Val = -MaxAlign;
+ MachineInstr *MI =
+ BuildMI(MBB, MBBI, DL, TII.get(getANDriOpcode(Uses64BitFramePtr, Val)),
+ StackPtr)
+ .addReg(StackPtr)
+ .addImm(Val)
+ .setMIFlag(MachineInstr::FrameSetup);
+
+ // The EFLAGS implicit def is dead.
+ MI->getOperand(3).setIsDead();
}
// If we need a base pointer, set it up here. It's whatever the value
if (!HasFP && NumBytes) {
// Define the current CFA rule to use the provided offset.
assert(StackSize);
- unsigned CFIIndex = MMI.addFrameInst(
- MCCFIInstruction::createDefCfaOffset(nullptr,
- -StackSize + stackGrowth));
-
- BuildMI(MBB, MBBI, DL, TII.get(TargetOpcode::CFI_INSTRUCTION))
- .addCFIIndex(CFIIndex);
+ BuildCFI(MBB, MBBI, DL, TII, MCCFIInstruction::createDefCfaOffset(
+ nullptr, -StackSize + stackGrowth));
}
// Emit DWARF info specifying the offsets of the callee-saved registers.
}
}
+bool X86FrameLowering::canUseLEAForSPInEpilogue(
+ const MachineFunction &MF) const {
+ // We can't use LEA instructions for adjusting the stack pointer if this is a
+ // leaf function in the Win64 ABI. Only ADD instructions may be used to
+ // deallocate the stack.
+ // This means that we can use LEA for SP in two situations:
+ // 1. We *aren't* using the Win64 ABI which means we are free to use LEA.
+ // 2. We *have* a frame pointer which means we are permitted to use LEA.
+ return !MF.getTarget().getMCAsmInfo()->usesWindowsCFI() || hasFP(MF);
+}
+
+/// Check whether or not the terminators of \p MBB needs to read EFLAGS.
+static bool terminatorsNeedFlagsAsInput(const MachineBasicBlock &MBB) {
+ for (const MachineInstr &MI : MBB.terminators()) {
+ bool BreakNext = false;
+ for (const MachineOperand &MO : MI.operands()) {
+ if (!MO.isReg())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (Reg != X86::EFLAGS)
+ continue;
+
+ // This terminator needs an eflag that is not defined
+ // by a previous terminator.
+ if (!MO.isDef())
+ return true;
+ BreakNext = true;
+ }
+ if (BreakNext)
+ break;
+ }
+ return false;
+}
+
void X86FrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
- const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo());
- const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
- MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
- assert(MBBI != MBB.end() && "Returning block has no instructions");
- unsigned RetOpcode = MBBI->getOpcode();
- DebugLoc DL = MBBI->getDebugLoc();
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const X86RegisterInfo *RegInfo = STI.getRegisterInfo();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
+ MachineBasicBlock::iterator MBBI = MBB.getFirstTerminator();
+ DebugLoc DL;
+ if (MBBI != MBB.end())
+ DL = MBBI->getDebugLoc();
bool Is64Bit = STI.is64Bit();
// standard x86_64 and NaCl use 64-bit frame/stack pointers, x32 - 32-bit.
const bool Uses64BitFramePtr = STI.isTarget64BitLP64() || STI.isTargetNaCl64();
const bool Is64BitILP32 = STI.isTarget64BitILP32();
- bool UseLEA = STI.useLeaForSP();
- unsigned StackAlign = getStackAlignment();
unsigned SlotSize = RegInfo->getSlotSize();
unsigned FramePtr = RegInfo->getFrameRegister(MF);
- unsigned MachineFramePtr = Is64BitILP32 ?
- getX86SubSuperRegister(FramePtr, MVT::i64, false) : FramePtr;
+ unsigned MachineFramePtr =
+ Is64BitILP32 ? getX86SubSuperRegister(FramePtr, MVT::i64, false)
+ : FramePtr;
unsigned StackPtr = RegInfo->getStackRegister();
- bool IsWinEH = MF.getTarget().getMCAsmInfo()->getExceptionHandlingType() ==
- ExceptionHandling::ItaniumWinEH;
- bool NeedsWinEH = IsWinEH && MF.getFunction()->needsUnwindTableEntry();
-
- switch (RetOpcode) {
- default:
- llvm_unreachable("Can only insert epilog into returning blocks");
- case X86::RETQ:
- case X86::RETL:
- case X86::RETIL:
- case X86::RETIQ:
- case X86::TCRETURNdi:
- case X86::TCRETURNri:
- case X86::TCRETURNmi:
- case X86::TCRETURNdi64:
- case X86::TCRETURNri64:
- case X86::TCRETURNmi64:
- case X86::EH_RETURN:
- case X86::EH_RETURN64:
- break; // These are ok
- }
+ bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ bool NeedsWinCFI =
+ IsWin64Prologue && MF.getFunction()->needsUnwindTableEntry();
+ bool UseLEAForSP = canUseLEAForSPInEpilogue(MF);
+ // If we can use LEA for SP but we shouldn't, check that none
+ // of the terminators uses the eflags. Otherwise we will insert
+ // a ADD that will redefine the eflags and break the condition.
+ // Alternatively, we could move the ADD, but this may not be possible
+ // and is an optimization anyway.
+ if (UseLEAForSP && !MF.getSubtarget<X86Subtarget>().useLeaForSP())
+ UseLEAForSP = terminatorsNeedFlagsAsInput(MBB);
+ // If that assert breaks, that means we do not do the right thing
+ // in canUseAsEpilogue.
+ assert((UseLEAForSP || !terminatorsNeedFlagsAsInput(MBB)) &&
+ "We shouldn't have allowed this insertion point");
// Get the number of bytes to allocate from the FrameInfo.
uint64_t StackSize = MFI->getStackSize();
- uint64_t MaxAlign = MFI->getMaxAlignment();
+ uint64_t MaxAlign = calculateMaxStackAlign(MF);
unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t NumBytes = 0;
- // If we're forcing a stack realignment we can't rely on just the frame
- // info, we need to know the ABI stack alignment as well in case we
- // have a call out. Otherwise just make sure we have some alignment - we'll
- // go with the minimum.
- if (ForceStackAlign) {
- if (MFI->hasCalls())
- MaxAlign = (StackAlign > MaxAlign) ? StackAlign : MaxAlign;
- else
- MaxAlign = MaxAlign ? MaxAlign : 4;
- }
-
if (hasFP(MF)) {
// Calculate required stack adjustment.
uint64_t FrameSize = StackSize - SlotSize;
- if (RegInfo->needsStackRealignment(MF)) {
- // Callee-saved registers were pushed on stack before the stack
- // was realigned.
- FrameSize -= CSSize;
- NumBytes = (FrameSize + MaxAlign - 1) / MaxAlign * MaxAlign;
- } else {
- NumBytes = FrameSize - CSSize;
- }
+ NumBytes = FrameSize - CSSize;
+
+ // Callee-saved registers were pushed on stack before the stack was
+ // realigned.
+ if (RegInfo->needsStackRealignment(MF) && !IsWin64Prologue)
+ NumBytes = RoundUpToAlignment(FrameSize, MaxAlign);
// Pop EBP.
BuildMI(MBB, MBBI, DL,
} else {
NumBytes = StackSize - CSSize;
}
+ uint64_t SEHStackAllocAmt = NumBytes;
// Skip the callee-saved pop instructions.
while (MBBI != MBB.begin()) {
}
MachineBasicBlock::iterator FirstCSPop = MBBI;
- DL = MBBI->getDebugLoc();
+ if (MBBI != MBB.end())
+ DL = MBBI->getDebugLoc();
// If there is an ADD32ri or SUB32ri of ESP immediately before this
// instruction, merge the two instructions.
if (RegInfo->needsStackRealignment(MF) || MFI->hasVarSizedObjects()) {
if (RegInfo->needsStackRealignment(MF))
MBBI = FirstCSPop;
- if (CSSize != 0) {
+ unsigned SEHFrameOffset = calculateSetFPREG(SEHStackAllocAmt);
+ uint64_t LEAAmount =
+ IsWin64Prologue ? SEHStackAllocAmt - SEHFrameOffset : -CSSize;
+
+ // There are only two legal forms of epilogue:
+ // - add SEHAllocationSize, %rsp
+ // - lea SEHAllocationSize(%FramePtr), %rsp
+ //
+ // 'mov %FramePtr, %rsp' will not be recognized as an epilogue sequence.
+ // However, we may use this sequence if we have a frame pointer because the
+ // effects of the prologue can safely be undone.
+ if (LEAAmount != 0) {
unsigned Opc = getLEArOpcode(Uses64BitFramePtr);
addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(Opc), StackPtr),
- FramePtr, false, -CSSize);
+ FramePtr, false, LEAAmount);
--MBBI;
} else {
unsigned Opc = (Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr);
}
} else if (NumBytes) {
// Adjust stack pointer back: ESP += numbytes.
- emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, Uses64BitFramePtr, UseLEA,
- TII, *RegInfo);
+ emitSPUpdate(MBB, MBBI, StackPtr, NumBytes, Is64Bit, Uses64BitFramePtr,
+ UseLEAForSP, TII, *RegInfo);
--MBBI;
}
// into the epilogue. To cope with that, we insert an epilogue marker here,
// then replace it with a 'nop' if it ends up immediately after a CALL in the
// final emitted code.
- if (NeedsWinEH)
+ if (NeedsWinCFI)
BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_Epilogue));
- // We're returning from function via eh_return.
- if (RetOpcode == X86::EH_RETURN || RetOpcode == X86::EH_RETURN64) {
- MBBI = MBB.getLastNonDebugInstr();
- MachineOperand &DestAddr = MBBI->getOperand(0);
- assert(DestAddr.isReg() && "Offset should be in register!");
- BuildMI(MBB, MBBI, DL,
- TII.get(Uses64BitFramePtr ? X86::MOV64rr : X86::MOV32rr),
- StackPtr).addReg(DestAddr.getReg());
- } else if (RetOpcode == X86::TCRETURNri || RetOpcode == X86::TCRETURNdi ||
- RetOpcode == X86::TCRETURNmi ||
- RetOpcode == X86::TCRETURNri64 || RetOpcode == X86::TCRETURNdi64 ||
- RetOpcode == X86::TCRETURNmi64) {
- bool isMem = RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64;
- // Tail call return: adjust the stack pointer and jump to callee.
- MBBI = MBB.getLastNonDebugInstr();
- MachineOperand &JumpTarget = MBBI->getOperand(0);
- MachineOperand &StackAdjust = MBBI->getOperand(isMem ? 5 : 1);
- assert(StackAdjust.isImm() && "Expecting immediate value.");
-
- // Adjust stack pointer.
- int StackAdj = StackAdjust.getImm();
- int MaxTCDelta = X86FI->getTCReturnAddrDelta();
- int Offset = 0;
- assert(MaxTCDelta <= 0 && "MaxTCDelta should never be positive");
-
- // Incoporate the retaddr area.
- Offset = StackAdj-MaxTCDelta;
- assert(Offset >= 0 && "Offset should never be negative");
-
- if (Offset) {
- // Check for possible merge with preceding ADD instruction.
- Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
- emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, Uses64BitFramePtr,
- UseLEA, TII, *RegInfo);
- }
-
- // Jump to label or value in register.
- if (RetOpcode == X86::TCRETURNdi || RetOpcode == X86::TCRETURNdi64) {
- MachineInstrBuilder MIB =
- BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNdi)
- ? X86::TAILJMPd : X86::TAILJMPd64));
- if (JumpTarget.isGlobal())
- MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
- JumpTarget.getTargetFlags());
- else {
- assert(JumpTarget.isSymbol());
- MIB.addExternalSymbol(JumpTarget.getSymbolName(),
- JumpTarget.getTargetFlags());
- }
- } else if (RetOpcode == X86::TCRETURNmi || RetOpcode == X86::TCRETURNmi64) {
- MachineInstrBuilder MIB =
- BuildMI(MBB, MBBI, DL, TII.get((RetOpcode == X86::TCRETURNmi)
- ? X86::TAILJMPm : X86::TAILJMPm64));
- for (unsigned i = 0; i != 5; ++i)
- MIB.addOperand(MBBI->getOperand(i));
- } else if (RetOpcode == X86::TCRETURNri64) {
- BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr64)).
- addReg(JumpTarget.getReg(), RegState::Kill);
- } else {
- BuildMI(MBB, MBBI, DL, TII.get(X86::TAILJMPr)).
- addReg(JumpTarget.getReg(), RegState::Kill);
- }
-
- MachineInstr *NewMI = std::prev(MBBI);
- NewMI->copyImplicitOps(MF, MBBI);
-
- // Delete the pseudo instruction TCRETURN.
- MBB.erase(MBBI);
- } else if ((RetOpcode == X86::RETQ || RetOpcode == X86::RETL ||
- RetOpcode == X86::RETIQ || RetOpcode == X86::RETIL) &&
- (X86FI->getTCReturnAddrDelta() < 0)) {
- // Add the return addr area delta back since we are not tail calling.
- int delta = -1*X86FI->getTCReturnAddrDelta();
- MBBI = MBB.getLastNonDebugInstr();
+ // Add the return addr area delta back since we are not tail calling.
+ int Offset = -1 * X86FI->getTCReturnAddrDelta();
+ assert(Offset >= 0 && "TCDelta should never be positive");
+ if (Offset) {
+ MBBI = MBB.getFirstTerminator();
// Check for possible merge with preceding ADD instruction.
- delta += mergeSPUpdates(MBB, MBBI, StackPtr, true);
- emitSPUpdate(MBB, MBBI, StackPtr, delta, Is64Bit, Uses64BitFramePtr, UseLEA, TII,
- *RegInfo);
+ Offset += mergeSPUpdates(MBB, MBBI, StackPtr, true);
+ emitSPUpdate(MBB, MBBI, StackPtr, Offset, Is64Bit, Uses64BitFramePtr,
+ UseLEAForSP, TII, *RegInfo);
}
}
int X86FrameLowering::getFrameIndexOffset(const MachineFunction &MF,
int FI) const {
const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo());
+ MF.getSubtarget<X86Subtarget>().getRegisterInfo();
const MachineFrameInfo *MFI = MF.getFrameInfo();
+ // Offset will hold the offset from the stack pointer at function entry to the
+ // object.
+ // We need to factor in additional offsets applied during the prologue to the
+ // frame, base, and stack pointer depending on which is used.
int Offset = MFI->getObjectOffset(FI) - getOffsetOfLocalArea();
+ const X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
+ unsigned CSSize = X86FI->getCalleeSavedFrameSize();
uint64_t StackSize = MFI->getStackSize();
+ unsigned SlotSize = RegInfo->getSlotSize();
+ bool HasFP = hasFP(MF);
+ bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
+ int64_t FPDelta = 0;
+
+ if (IsWin64Prologue) {
+ assert(!MFI->hasCalls() || (StackSize % 16) == 8);
+
+ // Calculate required stack adjustment.
+ uint64_t FrameSize = StackSize - SlotSize;
+ // If required, include space for extra hidden slot for stashing base pointer.
+ if (X86FI->getRestoreBasePointer())
+ FrameSize += SlotSize;
+ uint64_t NumBytes = FrameSize - CSSize;
+
+ uint64_t SEHFrameOffset = calculateSetFPREG(NumBytes);
+ if (FI && FI == X86FI->getFAIndex())
+ return -SEHFrameOffset;
+
+ // FPDelta is the offset from the "traditional" FP location of the old base
+ // pointer followed by return address and the location required by the
+ // restricted Win64 prologue.
+ // Add FPDelta to all offsets below that go through the frame pointer.
+ FPDelta = FrameSize - SEHFrameOffset;
+ assert((!MFI->hasCalls() || (FPDelta % 16) == 0) &&
+ "FPDelta isn't aligned per the Win64 ABI!");
+ }
+
if (RegInfo->hasBasePointer(MF)) {
- assert (hasFP(MF) && "VLAs and dynamic stack realign, but no FP?!");
+ assert(HasFP && "VLAs and dynamic stack realign, but no FP?!");
if (FI < 0) {
// Skip the saved EBP.
- return Offset + RegInfo->getSlotSize();
+ return Offset + SlotSize + FPDelta;
} else {
assert((-(Offset + StackSize)) % MFI->getObjectAlignment(FI) == 0);
return Offset + StackSize;
} else if (RegInfo->needsStackRealignment(MF)) {
if (FI < 0) {
// Skip the saved EBP.
- return Offset + RegInfo->getSlotSize();
+ return Offset + SlotSize + FPDelta;
} else {
assert((-(Offset + StackSize)) % MFI->getObjectAlignment(FI) == 0);
return Offset + StackSize;
}
// FIXME: Support tail calls
} else {
- if (!hasFP(MF))
+ if (!HasFP)
return Offset + StackSize;
// Skip the saved EBP.
- Offset += RegInfo->getSlotSize();
+ Offset += SlotSize;
// Skip the RETADDR move area
- const X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
int TailCallReturnAddrDelta = X86FI->getTCReturnAddrDelta();
if (TailCallReturnAddrDelta < 0)
Offset -= TailCallReturnAddrDelta;
}
- return Offset;
+ return Offset + FPDelta;
}
int X86FrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
unsigned &FrameReg) const {
const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo());
+ MF.getSubtarget<X86Subtarget>().getRegisterInfo();
// We can't calculate offset from frame pointer if the stack is realigned,
// so enforce usage of stack/base pointer. The base pointer is used when we
// have dynamic allocas in addition to dynamic realignment.
int X86FrameLowering::getFrameIndexOffsetFromSP(const MachineFunction &MF, int FI) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
// Does not include any dynamic realign.
- const uint64_t StackSize = MFI->getStackSize();
+ const uint64_t StackSize = MFI->getStackSize();
{
#ifndef NDEBUG
const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo*>(MF.getSubtarget().getRegisterInfo());
+ MF.getSubtarget<X86Subtarget>().getRegisterInfo();
// Note: LLVM arranges the stack as:
// Args > Saved RetPC (<--FP) > CSRs > dynamic alignment (<--BP)
// > "Stack Slots" (<--SP)
// refer to arguments to the function which are stored in the *callers*
// frame). As a result, THE RESULT OF THIS CALL IS MEANINGLESS FOR CSRs
// AND FixedObjects IFF needsStackRealignment or hasVarSizedObject.
-
+
assert(!RegInfo->hasBasePointer(MF) && "we don't handle this case");
// We don't handle tail calls, and shouldn't be seeing them
return Offset + StackSize;
}
// Simplified from getFrameIndexReference keeping only StackPointer cases
-int X86FrameLowering::getFrameIndexReferenceFromSP(const MachineFunction &MF, int FI,
- unsigned &FrameReg) const {
+int X86FrameLowering::getFrameIndexReferenceFromSP(const MachineFunction &MF,
+ int FI,
+ unsigned &FrameReg) const {
const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo*>(MF.getSubtarget().getRegisterInfo());
-
+ MF.getSubtarget<X86Subtarget>().getRegisterInfo();
assert(!RegInfo->hasBasePointer(MF) && "we don't handle this case");
FrameReg = RegInfo->getStackRegister();
std::vector<CalleeSavedInfo> &CSI) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo());
+ MF.getSubtarget<X86Subtarget>().getRegisterInfo();
unsigned SlotSize = RegInfo->getSlotSize();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
DebugLoc DL = MBB.findDebugLoc(MI);
MachineFunction &MF = *MBB.getParent();
- const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
// Push GPRs. It increases frame size.
unsigned Opc = STI.is64Bit() ? X86::PUSH64r : X86::PUSH32r;
// It can be done by spilling XMMs to stack frame.
for (unsigned i = CSI.size(); i != 0; --i) {
unsigned Reg = CSI[i-1].getReg();
- if (X86::GR64RegClass.contains(Reg) ||
- X86::GR32RegClass.contains(Reg))
+ if (X86::GR64RegClass.contains(Reg) || X86::GR32RegClass.contains(Reg))
continue;
// Add the callee-saved register as live-in. It's killed at the spill.
MBB.addLiveIn(Reg);
DebugLoc DL = MBB.findDebugLoc(MI);
MachineFunction &MF = *MBB.getParent();
- const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
// Reload XMMs from stack frame.
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
RegScavenger *RS) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
const X86RegisterInfo *RegInfo =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo());
+ MF.getSubtarget<X86Subtarget>().getRegisterInfo();
unsigned SlotSize = RegInfo->getSlotSize();
X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
// limit.
static const uint64_t kSplitStackAvailable = 256;
-void
-X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const {
- MachineBasicBlock &prologueMBB = MF.front();
+void X86FrameLowering::adjustForSegmentedStacks(
+ MachineFunction &MF, MachineBasicBlock &PrologueMBB) const {
MachineFrameInfo *MFI = MF.getFrameInfo();
- const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
uint64_t StackSize;
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
bool Is64Bit = STI.is64Bit();
const bool IsLP64 = STI.isTarget64BitLP64();
unsigned TlsReg, TlsOffset;
if (MF.getFunction()->isVarArg())
report_fatal_error("Segmented stacks do not support vararg functions.");
- if (!STI.isTargetLinux() && !STI.isTargetDarwin() &&
- !STI.isTargetWin32() && !STI.isTargetWin64() && !STI.isTargetFreeBSD())
+ if (!STI.isTargetLinux() && !STI.isTargetDarwin() && !STI.isTargetWin32() &&
+ !STI.isTargetWin64() && !STI.isTargetFreeBSD() &&
+ !STI.isTargetDragonFly())
report_fatal_error("Segmented stacks not supported on this platform.");
// Eventually StackSize will be calculated by a link-time pass; which will
// The MOV R10, RAX needs to be in a different block, since the RET we emit in
// allocMBB needs to be last (terminating) instruction.
- for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(),
- e = prologueMBB.livein_end(); i != e; i++) {
+ for (MachineBasicBlock::livein_iterator i = PrologueMBB.livein_begin(),
+ e = PrologueMBB.livein_end();
+ i != e; i++) {
allocMBB->addLiveIn(*i);
checkMBB->addLiveIn(*i);
}
} else if (STI.isTargetFreeBSD()) {
TlsReg = X86::FS;
TlsOffset = 0x18;
+ } else if (STI.isTargetDragonFly()) {
+ TlsReg = X86::FS;
+ TlsOffset = 0x20; // use tls_tcb.tcb_segstack
} else {
report_fatal_error("Segmented stacks not supported on this platform.");
}
} else if (STI.isTargetWin32()) {
TlsReg = X86::FS;
TlsOffset = 0x14; // pvArbitrary, reserved for application use
+ } else if (STI.isTargetDragonFly()) {
+ TlsReg = X86::FS;
+ TlsOffset = 0x10; // use tls_tcb.tcb_segstack
} else if (STI.isTargetFreeBSD()) {
report_fatal_error("Segmented stacks not supported on FreeBSD i386.");
} else {
BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP)
.addImm(1).addReg(0).addImm(-StackSize).addReg(0);
- if (STI.isTargetLinux() || STI.isTargetWin32() || STI.isTargetWin64()) {
+ if (STI.isTargetLinux() || STI.isTargetWin32() || STI.isTargetWin64() ||
+ STI.isTargetDragonFly()) {
BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)).addReg(ScratchReg)
.addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg);
} else if (STI.isTargetDarwin()) {
// 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::JA_4)).addMBB(&prologueMBB);
+ BuildMI(checkMBB, DL, TII.get(X86::JA_1)).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.
}
// __morestack is in libgcc
- if (Is64Bit)
- BuildMI(allocMBB, DL, TII.get(X86::CALL64pcrel32))
- .addExternalSymbol("__morestack");
- else
- BuildMI(allocMBB, DL, TII.get(X86::CALLpcrel32))
- .addExternalSymbol("__morestack");
+ if (Is64Bit && MF.getTarget().getCodeModel() == CodeModel::Large) {
+ // Under the large code model, we cannot assume that __morestack lives
+ // within 2^31 bytes of the call site, so we cannot use pc-relative
+ // addressing. We cannot perform the call via a temporary register,
+ // as the rax register may be used to store the static chain, and all
+ // other suitable registers may be either callee-save or used for
+ // parameter passing. We cannot use the stack at this point either
+ // because __morestack manipulates the stack directly.
+ //
+ // To avoid these issues, perform an indirect call via a read-only memory
+ // location containing the address.
+ //
+ // This solution is not perfect, as it assumes that the .rodata section
+ // is laid out within 2^31 bytes of each function body, but this seems
+ // to be sufficient for JIT.
+ BuildMI(allocMBB, DL, TII.get(X86::CALL64m))
+ .addReg(X86::RIP)
+ .addImm(0)
+ .addReg(0)
+ .addExternalSymbol("__morestack_addr")
+ .addReg(0);
+ MF.getMMI().setUsesMorestackAddr(true);
+ } else {
+ if (Is64Bit)
+ BuildMI(allocMBB, DL, TII.get(X86::CALL64pcrel32))
+ .addExternalSymbol("__morestack");
+ else
+ BuildMI(allocMBB, DL, TII.get(X86::CALLpcrel32))
+ .addExternalSymbol("__morestack");
+ }
if (IsNested)
BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET_RESTORE_R10));
else
BuildMI(allocMBB, DL, TII.get(X86::MORESTACK_RET));
- allocMBB->addSuccessor(&prologueMBB);
+ allocMBB->addSuccessor(&PrologueMBB);
checkMBB->addSuccessor(allocMBB);
- checkMBB->addSuccessor(&prologueMBB);
+ checkMBB->addSuccessor(&PrologueMBB);
#ifdef XDEBUG
MF.verify();
/// 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 TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
+void X86FrameLowering::adjustForHiPEPrologue(
+ MachineFunction &MF, MachineBasicBlock &PrologueMBB) const {
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
MachineFrameInfo *MFI = MF.getFrameInfo();
- const unsigned SlotSize =
- static_cast<const X86RegisterInfo *>(MF.getSubtarget().getRegisterInfo())
- ->getSlotSize();
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
+ const unsigned SlotSize = STI.getRegisterInfo()->getSlotSize();
const bool Is64Bit = STI.is64Bit();
const bool IsLP64 = STI.isTarget64BitLP64();
DebugLoc DL;
// 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++) {
+ for (MachineBasicBlock::livein_iterator I = PrologueMBB.livein_begin(),
+ E = PrologueMBB.livein_end();
+ I != E; I++) {
stackCheckMBB->addLiveIn(*I);
incStackMBB->addLiveIn(*I);
}
// 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);
+ BuildMI(stackCheckMBB, DL, TII.get(X86::JAE_1)).addMBB(&PrologueMBB);
// Create new MBB for IncStack:
BuildMI(incStackMBB, DL, TII.get(CALLop)).
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);
+ BuildMI(incStackMBB, DL, TII.get(X86::JLE_1)).addMBB(incStackMBB);
- stackCheckMBB->addSuccessor(&prologueMBB, 99);
+ stackCheckMBB->addSuccessor(&PrologueMBB, 99);
stackCheckMBB->addSuccessor(incStackMBB, 1);
- incStackMBB->addSuccessor(&prologueMBB, 99);
+ incStackMBB->addSuccessor(&PrologueMBB, 99);
incStackMBB->addSuccessor(incStackMBB, 1);
}
#ifdef XDEBUG
void X86FrameLowering::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
- const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
- const X86RegisterInfo &RegInfo = *static_cast<const X86RegisterInfo *>(
- MF.getSubtarget().getRegisterInfo());
+ const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
+ const TargetInstrInfo &TII = *STI.getInstrInfo();
+ const X86RegisterInfo &RegInfo = *STI.getRegisterInfo();
unsigned StackPtr = RegInfo.getStackRegister();
- bool reseveCallFrame = hasReservedCallFrame(MF);
- int Opcode = I->getOpcode();
+ bool reserveCallFrame = hasReservedCallFrame(MF);
+ unsigned Opcode = I->getOpcode();
bool isDestroy = Opcode == TII.getCallFrameDestroyOpcode();
- const X86Subtarget &STI = MF.getTarget().getSubtarget<X86Subtarget>();
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;
+ uint64_t Amount = !reserveCallFrame ? I->getOperand(0).getImm() : 0;
+ uint64_t InternalAmt = (isDestroy || Amount) ? I->getOperand(1).getImm() : 0;
I = MBB.erase(I);
- if (!reseveCallFrame) {
+ if (!reserveCallFrame) {
// 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 = MF.getTarget()
- .getSubtargetImpl()
- ->getFrameLowering()
- ->getStackAlignment();
- Amount = (Amount + StackAlign - 1) / StackAlign * StackAlign;
+ unsigned StackAlign = getStackAlignment();
+ Amount = RoundUpToAlignment(Amount, StackAlign);
MachineInstr *New = nullptr;
- 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;
+ // Factor out the amount that gets handled inside the sequence
+ // (Pushes of argument for frame setup, callee pops for frame destroy)
+ Amount -= InternalAmt;
+
+ if (Amount) {
+ if (Opcode == TII.getCallFrameSetupOpcode()) {
+ New = BuildMI(MF, DL, TII.get(getSUBriOpcode(IsLP64, Amount)), StackPtr)
+ .addReg(StackPtr).addImm(Amount);
+ } else {
+ assert(Opcode == TII.getCallFrameDestroyOpcode());
- if (Amount) {
unsigned Opc = getADDriOpcode(IsLP64, Amount);
New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
.addReg(StackPtr).addImm(Amount);
return;
}
- if (Opcode == TII.getCallFrameDestroyOpcode() && CalleeAmt) {
+ if (Opcode == TII.getCallFrameDestroyOpcode() && InternalAmt) {
// 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);
+ unsigned Opc = getSUBriOpcode(IsLP64, InternalAmt);
MachineInstr *New = BuildMI(MF, DL, TII.get(Opc), StackPtr)
- .addReg(StackPtr).addImm(CalleeAmt);
+ .addReg(StackPtr).addImm(InternalAmt);
// The EFLAGS implicit def is dead.
New->getOperand(3).setIsDead();
}
}
+bool X86FrameLowering::canUseAsEpilogue(const MachineBasicBlock &MBB) const {
+ assert(MBB.getParent() && "Block is not attached to a function!");
+
+ if (canUseLEAForSPInEpilogue(*MBB.getParent()))
+ return true;
+
+ // If we cannot use LEA to adjust SP, we may need to use ADD, which
+ // clobbers the EFLAGS. Check that none of the terminators reads the
+ // EFLAGS, and if one uses it, conservatively assume this is not
+ // safe to insert the epilogue here.
+ return !terminatorsNeedFlagsAsInput(MBB);
+}
projects / oota-llvm.git / blobdiff