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RuntimeLibcalls: Add entries for stack probe functions #167453

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RuntimeLibcalls: Add entries for stack probe functions
arsenm Aug 3, 2025
cd2660d
Remove __chkstk_ms
arsenm Nov 11, 2025
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35 changes: 33 additions & 2 deletions llvm/include/llvm/IR/RuntimeLibcalls.td
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Expand Up @@ -406,6 +406,7 @@ def STACK_SMASH_HANDLER : RuntimeLibcall;
// Safe stack
def SAFESTACK_POINTER_ADDRESS : RuntimeLibcall;

def STACK_PROBE : RuntimeLibcall;
def SECURITY_CHECK_COOKIE : RuntimeLibcall;

// Deoptimization
Expand Down Expand Up @@ -1084,6 +1085,13 @@ def __stack_smash_handler : RuntimeLibcallImpl<STACK_SMASH_HANDLER>;

def __riscv_flush_icache : RuntimeLibcallImpl<RISCV_FLUSH_ICACHE>;

def _chkstk : RuntimeLibcallImpl<STACK_PROBE>;
def _alloca : RuntimeLibcallImpl<STACK_PROBE>;

def __chkstk : RuntimeLibcallImpl<STACK_PROBE>;
def ___chkstk_ms : RuntimeLibcallImpl<STACK_PROBE>;
Comment on lines +1088 to +1092
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@compnerd compnerd Nov 11, 2025

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Can we merge __chkstk and _chkstk. They are not different names, they are the same name, the difference is __USER_LABEL_PREFIX__.

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@arsenm arsenm Nov 11, 2025

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I assume the same applies for ___chkstk_ms and __chkstk_ms?

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@compnerd compnerd Nov 11, 2025

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Yes

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@efriedma-quic efriedma-quic Nov 11, 2025 •
edited
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__chkstk and _chkstk are actually different symbols, I think? See #167303. CC @mstorsjo

I think there's only one __chkstk_ms, though.

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@arsenm arsenm Nov 11, 2025

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If I try to use getNameWithPrefix or otherwise manually prepend getGlobalPrefix, it doesn't seem to be working out

def __chkstk_arm64ec : RuntimeLibcallImpl<STACK_PROBE, "#__chkstk_arm64ec">;

def __security_check_cookie : RuntimeLibcallImpl<SECURITY_CHECK_COOKIE>;
def __security_check_cookie_arm64ec : RuntimeLibcallImpl<SECURITY_CHECK_COOKIE,
"#__security_check_cookie_arm64ec">;
Expand Down Expand Up @@ -1260,6 +1268,9 @@ defvar SecurityCheckCookieIfWinMSVC =
LibcallImpls<(add __security_check_cookie, __security_cookie),
isWindowsMSVCOrItaniumEnvironment>;

defvar __chkstk_IfWinMSVC =
LibcallImpls<(add __chkstk), isWindowsMSVCEnvironment>;

defvar LibmHasSinCosF32 = LibcallImpls<(add sincosf), hasSinCos>;
defvar LibmHasSinCosF64 = LibcallImpls<(add sincos), hasSinCos>;
defvar LibmHasSinCosF80 = LibcallImpls<(add sincosl_f80), hasSinCos>;
Expand Down Expand Up @@ -1418,6 +1429,7 @@ def AArch64SystemLibrary : SystemRuntimeLibrary<
DefaultLibmExp10,
DefaultStackProtector,
SecurityCheckCookieIfWinMSVC,
__chkstk_IfWinMSVC,
SMEABI_LibCalls_PreserveMost_From_X0,
SMEABI_LibCalls_PreserveMost_From_X1,
SMEABI_LibCalls_PreserveMost_From_X2)
Expand Down Expand Up @@ -1465,6 +1477,7 @@ def WindowsARM64ECSystemLibrary
LibcallImpls<(add __security_check_cookie_arm64ec,
__security_cookie),
isWindowsMSVCEnvironment>,
__chkstk_arm64ec,
ExceptionModelCallsArm64EC)>;

//===----------------------------------------------------------------------===//
Expand Down Expand Up @@ -1882,6 +1895,7 @@ def ARMSystemLibrary
WindowARMDivRemCalls,
WindowARMFPIntCasts,
SecurityCheckCookieIfWinMSVC,
LibcallImpls<(add __chkstk), isOSWindows>,
AEABIDivRemCalls,
DarwinSinCosStret, DarwinExp10,
LibmHasSinCosF32, LibmHasSinCosF64, LibmHasSinCosF128,
Expand Down Expand Up @@ -2552,6 +2566,19 @@ def isX86_32 : RuntimeLibcallPredicate<"TT.getArch() == Triple::x86">;
def isX86_64 : RuntimeLibcallPredicate<"TT.getArch() == Triple::x86_64">;
def isX86 : RuntimeLibcallPredicate<"TT.isX86()">;

def isCygwinMinGW64 : RuntimeLibcallPredicate<
[{TT.isOSCygMing() && TT.getArch() == Triple::x86_64}]>;
def isCygwinMinGW32 : RuntimeLibcallPredicate<
[{TT.isOSCygMing() && TT.getArch() == Triple::x86}]>;

def isWin32NotCygMing : RuntimeLibcallPredicate<
[{TT.getArch() == Triple::x86 &&
(TT.isOSWindows() || TT.isUEFI()) && !TT.isOSCygMing()}]>;
def isWin64NotCygMing : RuntimeLibcallPredicate<
[{TT.getArch() == Triple::x86_64 &&
(TT.isOSWindows() || TT.isUEFI()) && !TT.isOSCygMing()}]>;


// Some darwins have an optimized __bzero/bzero function.
def darwinHas__bzero : RuntimeLibcallPredicate<"TT.isMacOSX() && !TT.isMacOSXVersionLT(10, 6)">;

Expand Down Expand Up @@ -2581,8 +2608,12 @@ defvar X86CommonLibcalls =
// FIXME: MSVCRT doesn't have powi. The f128 case is added as a
// hack for one test relying on it.
__powitf2_f128,
DefaultStackProtector
);
DefaultStackProtector,
LibcallImpls<(add ___chkstk_ms), isCygwinMinGW64>,
LibcallImpls<(add __chkstk), isWin64NotCygMing>,
LibcallImpls<(add _alloca), isCygwinMinGW32>,
LibcallImpls<(add _chkstk), isWin32NotCygMing>
);

defvar Windows32DivRemMulCalls =
LibcallsWithCC<(add WindowsDivRemMulLibcalls), X86_STDCALL,
Expand Down
8 changes: 6 additions & 2 deletions llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
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Expand Up @@ -16857,11 +16857,15 @@ AArch64TargetLowering::LowerWindowsDYNAMIC_STACKALLOC(SDValue Op,
return DAG.getMergeValues(Ops, DL);
}

RTLIB::LibcallImpl ChkStkImpl = getLibcallImpl(RTLIB::STACK_PROBE);
if (ChkStkImpl == RTLIB::Unsupported)
return SDValue();

Chain = DAG.getCALLSEQ_START(Chain, 0, 0, DL);

EVT PtrVT = getPointerTy(DAG.getDataLayout());
SDValue Callee = DAG.getTargetExternalSymbol(Subtarget->getChkStkName(),
PtrVT, 0);
SDValue Callee = DAG.getTargetExternalSymbol(
getLibcallImplName(ChkStkImpl).data(), PtrVT, 0);

const AArch64RegisterInfo *TRI = Subtarget->getRegisterInfo();
const uint32_t *Mask = TRI->getWindowsStackProbePreservedMask();
Expand Down
7 changes: 6 additions & 1 deletion llvm/lib/Target/AArch64/AArch64PrologueEpilogue.cpp
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Expand Up @@ -1135,7 +1135,12 @@ void AArch64PrologueEmitter::emitWindowsStackProbe(
.setMIFlags(MachineInstr::FrameSetup);
}

const char *ChkStk = Subtarget.getChkStkName();
const AArch64TargetLowering *TLI = Subtarget.getTargetLowering();
RTLIB::LibcallImpl ChkStkLibcall = TLI->getLibcallImpl(RTLIB::STACK_PROBE);
if (ChkStkLibcall == RTLIB::Unsupported)
reportFatalUsageError("no available implementation of __chkstk");

const char *ChkStk = TLI->getLibcallImplName(ChkStkLibcall).data();
switch (MF.getTarget().getCodeModel()) {
case CodeModel::Tiny:
case CodeModel::Small:
Expand Down
6 changes: 0 additions & 6 deletions llvm/lib/Target/AArch64/AArch64Subtarget.h
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Expand Up @@ -450,12 +450,6 @@ class AArch64Subtarget final : public AArch64GenSubtargetInfo {
/// add + cnt instructions.
bool useScalarIncVL() const;

const char* getChkStkName() const {
if (isWindowsArm64EC())
return "#__chkstk_arm64ec";
return "__chkstk";
}

/// Choose a method of checking LR before performing a tail call.
AArch64PAuth::AuthCheckMethod
getAuthenticatedLRCheckMethod(const MachineFunction &MF) const;
Expand Down
12 changes: 9 additions & 3 deletions llvm/lib/Target/ARM/ARMFrameLowering.cpp
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Expand Up @@ -1138,6 +1138,12 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF,
.add(predOps(ARMCC::AL));
}

const ARMTargetLowering *TLI = STI.getTargetLowering();
RTLIB::LibcallImpl ChkStkLibcall = TLI->getLibcallImpl(RTLIB::STACK_PROBE);
if (ChkStkLibcall == RTLIB::Unsupported)
reportFatalUsageError("no available implementation of __chkstk");
const char *ChkStk = TLI->getLibcallImplName(ChkStkLibcall).data();

switch (TM.getCodeModel()) {
case CodeModel::Tiny:
llvm_unreachable("Tiny code model not available on ARM.");
Expand All @@ -1146,14 +1152,14 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF,
case CodeModel::Kernel:
BuildMI(MBB, MBBI, dl, TII.get(ARM::tBL))
.add(predOps(ARMCC::AL))
.addExternalSymbol("__chkstk")
.addExternalSymbol(ChkStk)
.addReg(ARM::R4, RegState::Implicit)
.setMIFlags(MachineInstr::FrameSetup);
break;
case CodeModel::Large:
BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi32imm), ARM::R12)
.addExternalSymbol("__chkstk")
.setMIFlags(MachineInstr::FrameSetup);
.addExternalSymbol(ChkStk)
.setMIFlags(MachineInstr::FrameSetup);

BuildMI(MBB, MBBI, dl, TII.get(ARM::tBLXr))
.add(predOps(ARMCC::AL))
Expand Down
9 changes: 7 additions & 2 deletions llvm/lib/Target/ARM/ARMISelLowering.cpp
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Expand Up @@ -11727,6 +11727,11 @@ ARMTargetLowering::EmitLowered__chkstk(MachineInstr &MI,
// -mcmodel=large, alleviating the need for the trampoline which may clobber
// IP.

RTLIB::LibcallImpl ChkStkLibcall = getLibcallImpl(RTLIB::STACK_PROBE);
if (ChkStkLibcall == RTLIB::Unsupported)
reportFatalUsageError("no available implementation of __chkstk");

const char *ChkStk = getLibcallImplName(ChkStkLibcall).data();
switch (TM.getCodeModel()) {
case CodeModel::Tiny:
llvm_unreachable("Tiny code model not available on ARM.");
Expand All @@ -11735,7 +11740,7 @@ ARMTargetLowering::EmitLowered__chkstk(MachineInstr &MI,
case CodeModel::Kernel:
BuildMI(*MBB, MI, DL, TII.get(ARM::tBL))
.add(predOps(ARMCC::AL))
.addExternalSymbol("__chkstk")
.addExternalSymbol(ChkStk)
.addReg(ARM::R4, RegState::Implicit | RegState::Kill)
.addReg(ARM::R4, RegState::Implicit | RegState::Define)
.addReg(ARM::R12,
Expand All @@ -11748,7 +11753,7 @@ ARMTargetLowering::EmitLowered__chkstk(MachineInstr &MI,
Register Reg = MRI.createVirtualRegister(&ARM::rGPRRegClass);

BuildMI(*MBB, MI, DL, TII.get(ARM::t2MOVi32imm), Reg)
.addExternalSymbol("__chkstk");
.addExternalSymbol(ChkStk);
BuildMI(*MBB, MI, DL, TII.get(gettBLXrOpcode(*MBB->getParent())))
.add(predOps(ARMCC::AL))
.addReg(Reg, RegState::Kill)
Expand Down
7 changes: 4 additions & 3 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Expand Up @@ -62436,9 +62436,10 @@ X86TargetLowering::getStackProbeSymbolName(const MachineFunction &MF) const {

// We need a stack probe to conform to the Windows ABI. Choose the right
// symbol.
if (Subtarget.is64Bit())
return Subtarget.isTargetCygMing() ? "___chkstk_ms" : "__chkstk";
return Subtarget.isTargetCygMing() ? "_alloca" : "_chkstk";
RTLIB::LibcallImpl StackProbeImpl = getLibcallImpl(RTLIB::STACK_PROBE);
if (StackProbeImpl == RTLIB::Unsupported)
return "";
return getLibcallImplName(StackProbeImpl);
}

unsigned
Expand Down
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