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CodeGen: Fix crash when no libcall is available for stackguard #164211

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Merged
merged 1 commit into from
Oct 23, 2025
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CodeGen: Fix crash when no libcall is available for stackguard #164211

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12 changes: 8 additions & 4 deletions llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1862,15 +1862,19 @@ bool IRTranslator::translateVectorDeinterleave2Intrinsic(

void IRTranslator::getStackGuard(Register DstReg,
MachineIRBuilder &MIRBuilder) {
Value *Global = TLI->getSDagStackGuard(*MF->getFunction().getParent());
if (!Global) {
LLVMContext &Ctx = MIRBuilder.getContext();
Ctx.diagnose(DiagnosticInfoGeneric("unable to lower stackguard"));
MIRBuilder.buildUndef(DstReg);
return;
}

const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
MRI->setRegClass(DstReg, TRI->getPointerRegClass());
auto MIB =
MIRBuilder.buildInstr(TargetOpcode::LOAD_STACK_GUARD, {DstReg}, {});

Value *Global = TLI->getSDagStackGuard(*MF->getFunction().getParent());
if (!Global)
return;

unsigned AddrSpace = Global->getType()->getPointerAddressSpace();
LLT PtrTy = LLT::pointer(AddrSpace, DL->getPointerSizeInBits(AddrSpace));

Expand Down
23 changes: 17 additions & 6 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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Expand Up @@ -3126,12 +3126,16 @@ void SelectionDAGBuilder::visitSPDescriptorParent(StackProtectorDescriptor &SPD,
if (TLI.useLoadStackGuardNode(M)) {
Guard = getLoadStackGuard(DAG, dl, Chain);
} else {
const Value *IRGuard = TLI.getSDagStackGuard(M);
SDValue GuardPtr = getValue(IRGuard);

Guard = DAG.getLoad(PtrMemTy, dl, Chain, GuardPtr,
MachinePointerInfo(IRGuard, 0), Align,
MachineMemOperand::MOVolatile);
if (const Value *IRGuard = TLI.getSDagStackGuard(M)) {
SDValue GuardPtr = getValue(IRGuard);
Guard = DAG.getLoad(PtrMemTy, dl, Chain, GuardPtr,
MachinePointerInfo(IRGuard, 0), Align,
MachineMemOperand::MOVolatile);
} else {
LLVMContext &Ctx = *DAG.getContext();
Ctx.diagnose(DiagnosticInfoGeneric("unable to lower stackguard"));
Guard = DAG.getPOISON(PtrMemTy);
}
}

// Perform the comparison via a getsetcc.
Expand Down Expand Up @@ -7361,6 +7365,13 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
Res = DAG.getPtrExtOrTrunc(Res, sdl, PtrTy);
} else {
const Value *Global = TLI.getSDagStackGuard(M);
if (!Global) {
LLVMContext &Ctx = *DAG.getContext();
Ctx.diagnose(DiagnosticInfoGeneric("unable to lower stackguard"));
setValue(&I, DAG.getPOISON(PtrTy));
return;
}

Align Align = DAG.getDataLayout().getPrefTypeAlign(Global->getType());
Res = DAG.getLoad(PtrTy, sdl, Chain, getValue(Global),
MachinePointerInfo(Global, 0), Align,
Expand Down
14 changes: 14 additions & 0 deletions llvm/test/CodeGen/AMDGPU/stackguard.ll
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@@ -0,0 +1,14 @@
; RUN: not llc -global-isel=0 -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -filetype=null %s 2>&1 | FileCheck %s
; RUN: not llc -global-isel -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -filetype=null %s 2>&1 | FileCheck %s

; FIXME: To actually support stackguard, need to fix intrinsic to
; return pointer in any address space.

; CHECK: error: unable to lower stackguard
define i1 @test_stackguard(ptr %p1) {
%p2 = call ptr @llvm.stackguard()
%res = icmp ne ptr %p2, %p1
ret i1 %res
}

declare ptr @llvm.stackguard()
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