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[cfi] Fix one -fno-sanitize-merge case, and add two TODOs #135438

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Merged
merged 2 commits into from
Apr 24, 2025
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[cfi] Fix one -fno-sanitize-merge case, and add two TODOs #135438

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936a510
[cfi] Fix one -fno-sanitize-merge case, and add two TODOs
thurstond Apr 11, 2025
8feef30
clang-format
thurstond Apr 11, 2025
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3 changes: 2 additions & 1 deletion clang/lib/CodeGen/CGClass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2961,7 +2961,8 @@ void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD,
}

if (CGM.getCodeGenOpts().SanitizeTrap.has(M)) {
EmitTrapCheck(TypeTest, SanitizerHandler::CFICheckFail);
bool NoMerge = !CGM.getCodeGenOpts().SanitizeMergeHandlers.has(M);
EmitTrapCheck(TypeTest, SanitizerHandler::CFICheckFail, NoMerge);
return;
}

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12 changes: 10 additions & 2 deletions clang/lib/CodeGen/CGExpr.cpp
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Expand Up @@ -3887,7 +3887,11 @@ void CodeGenFunction::EmitCfiCheckFail() {
// Data == nullptr means the calling module has trap behaviour for this check.
llvm::Value *DataIsNotNullPtr =
Builder.CreateICmpNE(Data, llvm::ConstantPointerNull::get(Int8PtrTy));
EmitTrapCheck(DataIsNotNullPtr, SanitizerHandler::CFICheckFail);
// TODO: since there is no data, we don't know the CheckKind, and therefore
// cannot inspect CGM.getCodeGenOpts().SanitizeMergeHandlers. We default to
// NoMerge = false. Users can disable merging by disabling optimization.
EmitTrapCheck(DataIsNotNullPtr, SanitizerHandler::CFICheckFail,
/*NoMerge=*/false);

llvm::StructType *SourceLocationTy =
llvm::StructType::get(VoidPtrTy, Int32Ty, Int32Ty);
Expand Down Expand Up @@ -3926,7 +3930,11 @@ void CodeGenFunction::EmitCfiCheckFail() {
EmitCheck(std::make_pair(Cond, Ordinal), SanitizerHandler::CFICheckFail,
{}, {Data, Addr, ValidVtable});
else
EmitTrapCheck(Cond, SanitizerHandler::CFICheckFail);
// TODO: we can't rely on CGM.getCodeGenOpts().SanitizeMergeHandlers.
// Although the compiler allows SanitizeMergeHandlers to be set
// independently of CGM.getLangOpts().Sanitize, Driver/SanitizerArgs.cpp
// requires that SanitizeMergeHandlers is a subset of Sanitize.
EmitTrapCheck(Cond, SanitizerHandler::CFICheckFail, /*NoMerge=*/false);
}

FinishFunction();
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