return false;
}
+void X86FrameLowering::getStackProbeFunction(const X86Subtarget &STI,
+ unsigned &CallOp,
+ const char *&Symbol) {
+ CallOp = STI.is64Bit() ? X86::W64ALLOCA : X86::CALLpcrel32;
+
+ if (STI.is64Bit()) {
+ if (STI.isTargetCygMing()) {
+ Symbol = "___chkstk_ms";
+ } else {
+ Symbol = "__chkstk";
+ }
+ } else if (STI.isTargetCygMing())
+ Symbol = "_alloca";
+ else
+ Symbol = "_chkstk";
+}
+
/// emitPrologue - Push callee-saved registers onto the stack, which
/// automatically adjust the stack pointer. Adjust the stack pointer to allocate
/// space for local variables. Also emit labels used by the exception handler to
X86FI->setCalleeSavedFrameSize(
X86FI->getCalleeSavedFrameSize() - TailCallReturnAddrDelta);
+ bool UseStackProbe = (STI.isOSWindows() && !STI.isTargetMacho());
+
// 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
// 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 >= 4096 && STI.isOSWindows() && !STI.isTargetMacho()) {
+ if (NumBytes >= PageSize && UseStackProbe) {
const char *StackProbeSymbol;
+ unsigned CallOp;
- if (Is64Bit) {
- if (STI.isTargetCygMing()) {
- StackProbeSymbol = "___chkstk_ms";
- } else {
- StackProbeSymbol = "__chkstk";
- }
- } else if (STI.isTargetCygMing())
- StackProbeSymbol = "_alloca";
- else
- StackProbeSymbol = "_chkstk";
+ getStackProbeFunction(STI, CallOp, StackProbeSymbol);
// Check whether EAX is livein for this function.
bool isEAXAlive = isEAXLiveIn(MF);
}
BuildMI(MBB, MBBI, DL,
- TII.get(Is64Bit ? X86::W64ALLOCA : X86::CALLpcrel32))
+ TII.get(CallOp))
.addExternalSymbol(StackProbeSymbol)
.addReg(StackPtr, RegState::Define | RegState::Implicit)
.addReg(X86::EFLAGS, RegState::Define | RegState::Implicit)
.setMIFlag(MachineInstr::FrameSetup);
}
if (isEAXAlive) {
- // Restore EAX
- MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),
- X86::EAX),
- StackPtr, false, NumBytes - 4);
- MI->setFlag(MachineInstr::FrameSetup);
- MBB.insert(MBBI, MI);
+ // Restore EAX
+ MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),
+ X86::EAX),
+ StackPtr, false, NumBytes - 4);
+ MI->setFlag(MachineInstr::FrameSetup);
+ MBB.insert(MBBI, MI);
}
} else if (NumBytes) {
emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, Uses64BitFramePtr,
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 =