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[AArch64][BTI] Mark EH landing pads as jump targets #149680

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[AArch64][BTI] Mark EH landing pads as jump targets #149680

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38698e6
[AArch64] Emit BTI j on EH landing pads ()
shashforge Jul 19, 2025
0b972ee
Merge branch 'main' into aarch64-bti-ehpad
shashforge Jul 22, 2025
a023d51
Merge branch 'main' into aarch64-bti-ehpad
shashforge Aug 18, 2025
4ad739b
Merge branch 'main' into aarch64-bti-ehpad
shashforge Aug 24, 2025
4a1c125
Merge branch 'main' into aarch64-bti-ehpad
shashforge Aug 25, 2025
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13 changes: 10 additions & 3 deletions llvm/lib/Target/AArch64/AArch64BranchTargets.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,6 @@ void AArch64BranchTargets::getAnalysisUsage(AnalysisUsage &AU) const {
FunctionPass *llvm::createAArch64BranchTargetsPass() {
return new AArch64BranchTargets();
}

bool AArch64BranchTargets::runOnMachineFunction(MachineFunction &MF) {
if (!MF.getInfo<AArch64FunctionInfo>()->branchTargetEnforcement())
return false;
Expand Down Expand Up @@ -100,7 +99,7 @@ bool AArch64BranchTargets::runOnMachineFunction(MachineFunction &MF) {
// If the block itself is address-taken, it could be indirectly branched
// to, but not called.
if (MBB.isMachineBlockAddressTaken() || MBB.isIRBlockAddressTaken() ||
JumpTableTargets.count(&MBB))
JumpTableTargets.count(&MBB) || MBB.isEHPad())
CouldJump = true;

if (CouldCall || CouldJump) {
Expand Down Expand Up @@ -147,7 +146,15 @@ void AArch64BranchTargets::addBTI(MachineBasicBlock &MBB, bool CouldCall,
BuildMI(MBB, MBB.begin(), MBB.findDebugLoc(MBB.begin()),
TII->get(AArch64::SEH_Nop));
}
BuildMI(MBB, MBB.begin(), MBB.findDebugLoc(MBB.begin()),

MBBI = MBB.begin();
if (MBB.isEHPad()) {
while (MBBI != MBB.end() &&
MBBI->getOpcode() == TargetOpcode::EH_LABEL)
++MBBI;
}

BuildMI(MBB, MBBI, MBB.findDebugLoc(MBBI),
TII->get(AArch64::HINT))
.addImm(HintNum);
}
26 changes: 26 additions & 0 deletions llvm/test/CodeGen/AArch64/bti-ehpad.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
; llvm/test/CodeGen/AArch64/bti-ehpad.ll
; REQUIRES: aarch64-registered-target
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@davemgreen davemgreen Aug 12, 2025

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Remove these, the REQUIRES is handled by the folder.
Also it looks like it would be worth running update_llc_test_checks.py to generate a good set of test checks.

; RUN: llc -mtriple=aarch64-none-linux-gnu %s -o - | FileCheck %s

declare i32 @__gxx_personality_v0(...)

define void @test() #0 personality ptr @__gxx_personality_v0 {
entry:
invoke void @may_throw()
to label %ret unwind label %lpad
lpad: ; catch.dispatch
landingpad { ptr, i32 }
cleanup
ret void
ret:
ret void
}

declare void @may_throw()

attributes #0 = { "branch-target-enforcement"="true" }

; Function needs both the architectural feature *and* the enforcement request.
attributes #0 = { "branch-target-enforcement"="true" "target-features"="+bti" }
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@davemgreen davemgreen Aug 12, 2025

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Don't define attribute #0 twice?


; CHECK: bti
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