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[NFC][CodeGen][CFI] Add GeneralizePointers parameter to GeneralizeFunctionType #158191

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Merged
merged 9 commits into from
Sep 13, 2025
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[NFC][CodeGen][CFI] Add GeneralizePointers parameter to GeneralizeFunctionType #158191

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44 changes: 26 additions & 18 deletions clang/lib/CodeGen/CodeGenModule.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2339,12 +2339,15 @@ llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
}

// Generalize pointer types to a void pointer with the qualifiers of the
// originally pointed-to type, e.g. 'const char *' and 'char * const *'
// generalize to 'const void *' while 'char *' and 'const char **' generalize to
// 'void *'.
static QualType GeneralizeType(ASTContext &Ctx, QualType Ty) {
if (!Ty->isPointerType())
// If `GeneralizePointers` is true, generalizes types to a void pointer with the
// qualifiers of the originally pointed-to type, e.g. 'const char *' and 'char *
// const *' generalize to 'const void *' while 'char *' and 'const char **'
// generalize to 'void *'.
static QualType GeneralizeType(ASTContext &Ctx, QualType Ty,
bool GeneralizePointers) {
// TODO: Add other generalizations.

if (!GeneralizePointers || !Ty->isPointerType())
return Ty;

return Ctx.getPointerType(
Expand All @@ -2353,26 +2356,29 @@ static QualType GeneralizeType(ASTContext &Ctx, QualType Ty) {
}

// Apply type generalization to a FunctionType's return and argument types
static QualType GeneralizeFunctionType(ASTContext &Ctx, QualType Ty) {
static QualType GeneralizeFunctionType(ASTContext &Ctx, QualType Ty,
bool GeneralizePointers) {
if (auto *FnType = Ty->getAs<FunctionProtoType>()) {
SmallVector<QualType, 8> GeneralizedParams;
for (auto &Param : FnType->param_types())
GeneralizedParams.push_back(GeneralizeType(Ctx, Param));
GeneralizedParams.push_back(
GeneralizeType(Ctx, Param, GeneralizePointers));

return Ctx.getFunctionType(GeneralizeType(Ctx, FnType->getReturnType()),
GeneralizedParams, FnType->getExtProtoInfo());
return Ctx.getFunctionType(
GeneralizeType(Ctx, FnType->getReturnType(), GeneralizePointers),
GeneralizedParams, FnType->getExtProtoInfo());
}

if (auto *FnType = Ty->getAs<FunctionNoProtoType>())
return Ctx.getFunctionNoProtoType(
GeneralizeType(Ctx, FnType->getReturnType()));
GeneralizeType(Ctx, FnType->getReturnType(), GeneralizePointers));

llvm_unreachable("Encountered unknown FunctionType");
}

llvm::ConstantInt *CodeGenModule::CreateKCFITypeId(QualType T, StringRef Salt) {
if (getCodeGenOpts().SanitizeCfiICallGeneralizePointers)
T = GeneralizeFunctionType(getContext(), T);
T = GeneralizeFunctionType(
getContext(), T, getCodeGenOpts().SanitizeCfiICallGeneralizePointers);
if (auto *FnType = T->getAs<FunctionProtoType>())
T = getContext().getFunctionType(
FnType->getReturnType(), FnType->getParamTypes(),
Expand Down Expand Up @@ -3041,11 +3047,13 @@ void CodeGenModule::createFunctionTypeMetadataForIcall(const FunctionDecl *FD,
if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
return;

QualType FnType = FD->getType();
QualType FnType = GeneralizeFunctionType(getContext(), FD->getType(),
/*GeneralizePointers=*/false);
llvm::Metadata *MD = CreateMetadataIdentifierForType(FnType);
F->addTypeMetadata(0, MD);

QualType GenPtrFnType = GeneralizeFunctionType(getContext(), FD->getType());
QualType GenPtrFnType = GeneralizeFunctionType(getContext(), FD->getType(),
/*GeneralizePointers=*/true);
F->addTypeMetadata(0, CreateMetadataIdentifierGeneralized(GenPtrFnType));

// Emit a hash-based bit set entry for cross-DSO calls.
Expand Down Expand Up @@ -7939,10 +7947,10 @@ CodeGenModule::CreateMetadataIdentifierImpl(QualType T, MetadataTypeMap &Map,

llvm::Metadata *CodeGenModule::CreateMetadataIdentifierForFnType(QualType T) {
assert(isa<FunctionType>(T));
if (getCodeGenOpts().SanitizeCfiICallGeneralizePointers) {
T = GeneralizeFunctionType(getContext(), T);
T = GeneralizeFunctionType(
getContext(), T, getCodeGenOpts().SanitizeCfiICallGeneralizePointers);
if (getCodeGenOpts().SanitizeCfiICallGeneralizePointers)
return CreateMetadataIdentifierGeneralized(T);
}
return CreateMetadataIdentifierForType(T);
}

Expand Down