[clang] ae18b94 - [PAC] Implement function pointer type discrimination (#96992)
via cfe-commits
cfe-commits at lists.llvm.org
Thu Jul 11 09:09:25 PDT 2024
Author: Akira Hatanaka
Date: 2024-07-11T09:09:20-07:00
New Revision: ae18b9410297963a379e03b94eae7433ff69a62b
URL: https://github.com/llvm/llvm-project/commit/ae18b9410297963a379e03b94eae7433ff69a62b
DIFF: https://github.com/llvm/llvm-project/commit/ae18b9410297963a379e03b94eae7433ff69a62b.diff
LOG: [PAC] Implement function pointer type discrimination (#96992)
Give users an option (-fptrauth-function-pointer-type-discrimination) to
sign a function pointer using a non-zero discriminator based on the
function type.
The discriminator is computed by first translating the function type to
a string and then computing the hash value of the string. Two function
types that are compatible in C must be translated to the same string
with the exception of function types that use typedefs of anonymous
structs in their return type or parameter types.
This patch doesn't have the code to resign function pointers, which is
needed when a function pointer is converted to a different function
type. That will be implemented in another patch.
Co-authored-by: John McCall <rjmccall at apple.com>
---------
Co-authored-by: John McCall <rjmccall at apple.com>
Added:
clang/test/CodeGen/ptrauth-function-type-discriminator.c
Modified:
clang/include/clang/AST/ASTContext.h
clang/include/clang/AST/Type.h
clang/include/clang/Basic/Features.def
clang/include/clang/Basic/LangOptions.def
clang/include/clang/CodeGen/CodeGenABITypes.h
clang/include/clang/Driver/Options.td
clang/lib/AST/ASTContext.cpp
clang/lib/CodeGen/CGExprConstant.cpp
clang/lib/CodeGen/CGPointerAuth.cpp
clang/lib/CodeGen/CodeGenModule.h
clang/lib/CodeGen/ConstantEmitter.h
clang/lib/Driver/ToolChains/Clang.cpp
clang/lib/Frontend/CompilerInvocation.cpp
clang/test/Preprocessor/ptrauth_feature.c
Removed:
################################################################################
diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index a99f2dc6eb3f2..57022e75073fe 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -1283,6 +1283,9 @@ class ASTContext : public RefCountedBase<ASTContext> {
uint16_t
getPointerAuthVTablePointerDiscriminator(const CXXRecordDecl *RD);
+ /// Return the "other" type-specific discriminator for the given type.
+ uint16_t getPointerAuthTypeDiscriminator(QualType T) const;
+
/// Apply Objective-C protocol qualifiers to the given type.
/// \param allowOnPointerType specifies if we can apply protocol
/// qualifiers on ObjCObjectPointerType. It can be set to true when
diff --git a/clang/include/clang/AST/Type.h b/clang/include/clang/AST/Type.h
index 62836ec5c6312..a2194361abd53 100644
--- a/clang/include/clang/AST/Type.h
+++ b/clang/include/clang/AST/Type.h
@@ -2509,6 +2509,7 @@ class alignas(TypeAlignment) Type : public ExtQualsTypeCommonBase {
bool isFunctionNoProtoType() const { return getAs<FunctionNoProtoType>(); }
bool isFunctionProtoType() const { return getAs<FunctionProtoType>(); }
bool isPointerType() const;
+ bool isSignableType() const;
bool isAnyPointerType() const; // Any C pointer or ObjC object pointer
bool isCountAttributedType() const;
bool isBlockPointerType() const;
@@ -8004,6 +8005,8 @@ inline bool Type::isAnyPointerType() const {
return isPointerType() || isObjCObjectPointerType();
}
+inline bool Type::isSignableType() const { return isPointerType(); }
+
inline bool Type::isBlockPointerType() const {
return isa<BlockPointerType>(CanonicalType);
}
diff --git a/clang/include/clang/Basic/Features.def b/clang/include/clang/Basic/Features.def
index 53f410d3cb4bd..2f864ff1c0edf 100644
--- a/clang/include/clang/Basic/Features.def
+++ b/clang/include/clang/Basic/Features.def
@@ -110,6 +110,7 @@ FEATURE(ptrauth_vtable_pointer_address_discrimination, LangOpts.PointerAuthVTPtr
FEATURE(ptrauth_vtable_pointer_type_discrimination, LangOpts.PointerAuthVTPtrTypeDiscrimination)
FEATURE(ptrauth_member_function_pointer_type_discrimination, LangOpts.PointerAuthCalls)
FEATURE(ptrauth_init_fini, LangOpts.PointerAuthInitFini)
+FEATURE(ptrauth_function_pointer_type_discrimination, LangOpts.PointerAuthFunctionTypeDiscrimination)
EXTENSION(swiftcc,
PP.getTargetInfo().checkCallingConvention(CC_Swift) ==
clang::TargetInfo::CCCR_OK)
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index d806b917432ad..5ad9c1f24b7c5 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -169,6 +169,8 @@ LANGOPT(PointerAuthAuthTraps, 1, 0, "pointer authentication failure traps")
LANGOPT(PointerAuthVTPtrAddressDiscrimination, 1, 0, "incorporate address discrimination in authenticated vtable pointers")
LANGOPT(PointerAuthVTPtrTypeDiscrimination, 1, 0, "incorporate type discrimination in authenticated vtable pointers")
LANGOPT(PointerAuthInitFini, 1, 0, "sign function pointers in init/fini arrays")
+BENIGN_LANGOPT(PointerAuthFunctionTypeDiscrimination, 1, 0,
+ "Use type discrimination when signing function pointers")
LANGOPT(DoubleSquareBracketAttributes, 1, 0, "'[[]]' attributes extension for all language standard modes")
LANGOPT(ExperimentalLateParseAttributes, 1, 0, "experimental late parsing of attributes")
diff --git a/clang/include/clang/CodeGen/CodeGenABITypes.h b/clang/include/clang/CodeGen/CodeGenABITypes.h
index d4822dc160082..9cbc5a8a2a3f4 100644
--- a/clang/include/clang/CodeGen/CodeGenABITypes.h
+++ b/clang/include/clang/CodeGen/CodeGenABITypes.h
@@ -108,6 +108,10 @@ unsigned getLLVMFieldNumber(CodeGenModule &CGM,
/// Return a declaration discriminator for the given global decl.
uint16_t getPointerAuthDeclDiscriminator(CodeGenModule &CGM, GlobalDecl GD);
+/// Return a type discriminator for the given function type.
+uint16_t getPointerAuthTypeDiscriminator(CodeGenModule &CGM,
+ QualType FunctionType);
+
/// Given the language and code-generation options that Clang was configured
/// with, set the default LLVM IR attributes for a function definition.
/// The attributes set here are mostly global target-configuration and
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 68a49b31f044f..a4859149bbfe3 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -4234,6 +4234,8 @@ defm ptrauth_vtable_pointer_address_discrimination :
defm ptrauth_vtable_pointer_type_discrimination :
OptInCC1FFlag<"ptrauth-vtable-pointer-type-discrimination", "Enable type discrimination of vtable pointers">;
defm ptrauth_init_fini : OptInCC1FFlag<"ptrauth-init-fini", "Enable signing of function pointers in init/fini arrays">;
+defm ptrauth_function_pointer_type_discrimination : OptInCC1FFlag<"ptrauth-function-pointer-type-discrimination",
+ "Enable type discrimination on C function pointers">;
}
def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>,
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 8e35e71d4a23e..497579dcc56b6 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -3140,6 +3140,285 @@ ASTContext::getPointerAuthVTablePointerDiscriminator(const CXXRecordDecl *RD) {
return llvm::getPointerAuthStableSipHash(Str);
}
+/// Encode a function type for use in the discriminator of a function pointer
+/// type. We can't use the itanium scheme for this since C has quite permissive
+/// rules for type compatibility that we need to be compatible with.
+///
+/// Formally, this function associates every function pointer type T with an
+/// encoded string E(T). Let the equivalence relation T1 ~ T2 be defined as
+/// E(T1) == E(T2). E(T) is part of the ABI of values of type T. C type
+/// compatibility requires equivalent treatment under the ABI, so
+/// CCompatible(T1, T2) must imply E(T1) == E(T2), that is, CCompatible must be
+/// a subset of ~. Crucially, however, it must be a proper subset because
+/// CCompatible is not an equivalence relation: for example, int[] is compatible
+/// with both int[1] and int[2], but the latter are not compatible with each
+/// other. Therefore this encoding function must be careful to only distinguish
+/// types if there is no third type with which they are both required to be
+/// compatible.
+static void encodeTypeForFunctionPointerAuth(const ASTContext &Ctx,
+ raw_ostream &OS, QualType QT) {
+ // FIXME: Consider address space qualifiers.
+ const Type *T = QT.getCanonicalType().getTypePtr();
+
+ // FIXME: Consider using the C++ type mangling when we encounter a construct
+ // that is incompatible with C.
+
+ switch (T->getTypeClass()) {
+ case Type::Atomic:
+ return encodeTypeForFunctionPointerAuth(
+ Ctx, OS, cast<AtomicType>(T)->getValueType());
+
+ case Type::LValueReference:
+ OS << "R";
+ encodeTypeForFunctionPointerAuth(Ctx, OS,
+ cast<ReferenceType>(T)->getPointeeType());
+ return;
+ case Type::RValueReference:
+ OS << "O";
+ encodeTypeForFunctionPointerAuth(Ctx, OS,
+ cast<ReferenceType>(T)->getPointeeType());
+ return;
+
+ case Type::Pointer:
+ // C11 6.7.6.1p2:
+ // For two pointer types to be compatible, both shall be identically
+ // qualified and both shall be pointers to compatible types.
+ // FIXME: we should also consider pointee types.
+ OS << "P";
+ return;
+
+ case Type::ObjCObjectPointer:
+ case Type::BlockPointer:
+ OS << "P";
+ return;
+
+ case Type::Complex:
+ OS << "C";
+ return encodeTypeForFunctionPointerAuth(
+ Ctx, OS, cast<ComplexType>(T)->getElementType());
+
+ case Type::VariableArray:
+ case Type::ConstantArray:
+ case Type::IncompleteArray:
+ case Type::ArrayParameter:
+ // C11 6.7.6.2p6:
+ // For two array types to be compatible, both shall have compatible
+ // element types, and if both size specifiers are present, and are integer
+ // constant expressions, then both size specifiers shall have the same
+ // constant value [...]
+ //
+ // So since ElemType[N] has to be compatible ElemType[], we can't encode the
+ // width of the array.
+ OS << "A";
+ return encodeTypeForFunctionPointerAuth(
+ Ctx, OS, cast<ArrayType>(T)->getElementType());
+
+ case Type::ObjCInterface:
+ case Type::ObjCObject:
+ OS << "<objc_object>";
+ return;
+
+ case Type::Enum:
+ // C11 6.7.2.2p4:
+ // Each enumerated type shall be compatible with char, a signed integer
+ // type, or an unsigned integer type.
+ //
+ // So we have to treat enum types as integers.
+ return encodeTypeForFunctionPointerAuth(
+ Ctx, OS, cast<EnumType>(T)->getDecl()->getIntegerType());
+
+ case Type::FunctionNoProto:
+ case Type::FunctionProto: {
+ // C11 6.7.6.3p15:
+ // For two function types to be compatible, both shall specify compatible
+ // return types. Moreover, the parameter type lists, if both are present,
+ // shall agree in the number of parameters and in the use of the ellipsis
+ // terminator; corresponding parameters shall have compatible types.
+ //
+ // That paragraph goes on to describe how unprototyped functions are to be
+ // handled, which we ignore here. Unprototyped function pointers are hashed
+ // as though they were prototyped nullary functions since thats probably
+ // what the user meant. This behavior is non-conforming.
+ // FIXME: If we add a "custom discriminator" function type attribute we
+ // should encode functions as their discriminators.
+ OS << "F";
+ const auto *FuncType = cast<FunctionType>(T);
+ encodeTypeForFunctionPointerAuth(Ctx, OS, FuncType->getReturnType());
+ if (const auto *FPT = dyn_cast<FunctionProtoType>(FuncType)) {
+ for (QualType Param : FPT->param_types()) {
+ Param = Ctx.getSignatureParameterType(Param);
+ encodeTypeForFunctionPointerAuth(Ctx, OS, Param);
+ }
+ if (FPT->isVariadic())
+ OS << "z";
+ }
+ OS << "E";
+ return;
+ }
+
+ case Type::MemberPointer: {
+ OS << "M";
+ const auto *MPT = T->getAs<MemberPointerType>();
+ encodeTypeForFunctionPointerAuth(Ctx, OS, QualType(MPT->getClass(), 0));
+ encodeTypeForFunctionPointerAuth(Ctx, OS, MPT->getPointeeType());
+ return;
+ }
+ case Type::ExtVector:
+ case Type::Vector:
+ OS << "Dv" << Ctx.getTypeSizeInChars(T).getQuantity();
+ break;
+
+ // Don't bother discriminating based on these types.
+ case Type::Pipe:
+ case Type::BitInt:
+ case Type::ConstantMatrix:
+ OS << "?";
+ return;
+
+ case Type::Builtin: {
+ const auto *BTy = T->getAs<BuiltinType>();
+ switch (BTy->getKind()) {
+#define SIGNED_TYPE(Id, SingletonId) \
+ case BuiltinType::Id: \
+ OS << "i"; \
+ return;
+#define UNSIGNED_TYPE(Id, SingletonId) \
+ case BuiltinType::Id: \
+ OS << "i"; \
+ return;
+#define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
+#define BUILTIN_TYPE(Id, SingletonId)
+#include "clang/AST/BuiltinTypes.def"
+ llvm_unreachable("placeholder types should not appear here.");
+
+ case BuiltinType::Half:
+ OS << "Dh";
+ return;
+ case BuiltinType::Float:
+ OS << "f";
+ return;
+ case BuiltinType::Double:
+ OS << "d";
+ return;
+ case BuiltinType::LongDouble:
+ OS << "e";
+ return;
+ case BuiltinType::Float16:
+ OS << "DF16_";
+ return;
+ case BuiltinType::Float128:
+ OS << "g";
+ return;
+
+ case BuiltinType::Void:
+ OS << "v";
+ return;
+
+ case BuiltinType::ObjCId:
+ case BuiltinType::ObjCClass:
+ case BuiltinType::ObjCSel:
+ case BuiltinType::NullPtr:
+ OS << "P";
+ return;
+
+ // Don't bother discriminating based on OpenCL types.
+ case BuiltinType::OCLSampler:
+ case BuiltinType::OCLEvent:
+ case BuiltinType::OCLClkEvent:
+ case BuiltinType::OCLQueue:
+ case BuiltinType::OCLReserveID:
+ case BuiltinType::BFloat16:
+ case BuiltinType::VectorQuad:
+ case BuiltinType::VectorPair:
+ OS << "?";
+ return;
+
+ // Don't bother discriminating based on these seldom-used types.
+ case BuiltinType::Ibm128:
+ return;
+#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
+ case BuiltinType::Id: \
+ return;
+#include "clang/Basic/OpenCLImageTypes.def"
+#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \
+ case BuiltinType::Id: \
+ return;
+#include "clang/Basic/OpenCLExtensionTypes.def"
+#define SVE_TYPE(Name, Id, SingletonId) \
+ case BuiltinType::Id: \
+ return;
+#include "clang/Basic/AArch64SVEACLETypes.def"
+ case BuiltinType::Dependent:
+ llvm_unreachable("should never get here");
+ case BuiltinType::AMDGPUBufferRsrc:
+ case BuiltinType::WasmExternRef:
+#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id:
+#include "clang/Basic/RISCVVTypes.def"
+ llvm_unreachable("not yet implemented");
+ }
+ }
+ case Type::Record: {
+ const RecordDecl *RD = T->getAs<RecordType>()->getDecl();
+ const IdentifierInfo *II = RD->getIdentifier();
+
+ // In C++, an immediate typedef of an anonymous struct or union
+ // is considered to name it for ODR purposes, but C's specification
+ // of type compatibility does not have a similar rule. Using the typedef
+ // name in function type discriminators anyway, as we do here,
+ // therefore technically violates the C standard: two function pointer
+ // types defined in terms of two typedef'd anonymous structs with
+ //
diff erent names are formally still compatible, but we are assigning
+ // them
diff erent discriminators and therefore incompatible ABIs.
+ //
+ // This is a relatively minor violation that significantly improves
+ // discrimination in some cases and has not caused problems in
+ // practice. Regardless, it is now part of the ABI in places where
+ // function type discrimination is used, and it can no longer be
+ // changed except on new platforms.
+
+ if (!II)
+ if (const TypedefNameDecl *Typedef = RD->getTypedefNameForAnonDecl())
+ II = Typedef->getDeclName().getAsIdentifierInfo();
+
+ if (!II) {
+ OS << "<anonymous_record>";
+ return;
+ }
+ OS << II->getLength() << II->getName();
+ return;
+ }
+ case Type::DeducedTemplateSpecialization:
+ case Type::Auto:
+#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
+#define DEPENDENT_TYPE(Class, Base) case Type::Class:
+#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
+#define ABSTRACT_TYPE(Class, Base)
+#define TYPE(Class, Base)
+#include "clang/AST/TypeNodes.inc"
+ llvm_unreachable("unexpected non-canonical or dependent type!");
+ return;
+ }
+}
+
+uint16_t ASTContext::getPointerAuthTypeDiscriminator(QualType T) const {
+ assert(!T->isDependentType() &&
+ "cannot compute type discriminator of a dependent type");
+
+ SmallString<256> Str;
+ llvm::raw_svector_ostream Out(Str);
+
+ if (T->isFunctionPointerType() || T->isFunctionReferenceType())
+ T = T->getPointeeType();
+
+ if (T->isFunctionType())
+ encodeTypeForFunctionPointerAuth(*this, Out, T);
+ else
+ llvm_unreachable(
+ "type discrimination of non-function type not implemented yet");
+
+ return llvm::getPointerAuthStableSipHash(Str);
+}
+
QualType ASTContext::getObjCGCQualType(QualType T,
Qualifiers::GC GCAttr) const {
QualType CanT = getCanonicalType(T);
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 1fec587b5c4c7..00a5a7e6898a8 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -1542,9 +1542,11 @@ ConstantEmitter::emitAbstract(const Expr *E, QualType destType) {
llvm::Constant *
ConstantEmitter::emitAbstract(SourceLocation loc, const APValue &value,
- QualType destType) {
+ QualType destType,
+ bool EnablePtrAuthFunctionTypeDiscrimination) {
auto state = pushAbstract();
- auto C = tryEmitPrivate(value, destType);
+ auto C =
+ tryEmitPrivate(value, destType, EnablePtrAuthFunctionTypeDiscrimination);
C = validateAndPopAbstract(C, state);
if (!C) {
CGM.Error(loc,
@@ -1938,14 +1940,18 @@ class ConstantLValueEmitter : public ConstStmtVisitor<ConstantLValueEmitter,
ConstantEmitter &Emitter;
const APValue &Value;
QualType DestType;
+ bool EnablePtrAuthFunctionTypeDiscrimination;
// Befriend StmtVisitorBase so that we don't have to expose Visit*.
friend StmtVisitorBase;
public:
ConstantLValueEmitter(ConstantEmitter &emitter, const APValue &value,
- QualType destType)
- : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType) {}
+ QualType destType,
+ bool EnablePtrAuthFunctionTypeDiscrimination = true)
+ : CGM(emitter.CGM), Emitter(emitter), Value(value), DestType(destType),
+ EnablePtrAuthFunctionTypeDiscrimination(
+ EnablePtrAuthFunctionTypeDiscrimination) {}
llvm::Constant *tryEmit();
@@ -2069,7 +2075,10 @@ ConstantLValueEmitter::tryEmitBase(const APValue::LValueBase &base) {
return CGM.GetWeakRefReference(D).getPointer();
auto PtrAuthSign = [&](llvm::Constant *C) {
- CGPointerAuthInfo AuthInfo = CGM.getFunctionPointerAuthInfo(DestType);
+ CGPointerAuthInfo AuthInfo;
+
+ if (EnablePtrAuthFunctionTypeDiscrimination)
+ AuthInfo = CGM.getFunctionPointerAuthInfo(DestType);
if (AuthInfo) {
if (hasNonZeroOffset())
@@ -2220,8 +2229,10 @@ llvm::Constant *ConstantLValueEmitter::emitPointerAuthPointer(const Expr *E) {
// The assertions here are all checked by Sema.
assert(Result.Val.isLValue());
+ if (isa<FunctionDecl>(Result.Val.getLValueBase().get<const ValueDecl *>()))
+ assert(Result.Val.getLValueOffset().isZero());
return ConstantEmitter(CGM, Emitter.CGF)
- .emitAbstract(E->getExprLoc(), Result.Val, E->getType());
+ .emitAbstract(E->getExprLoc(), Result.Val, E->getType(), false);
}
unsigned ConstantLValueEmitter::emitPointerAuthKey(const Expr *E) {
@@ -2278,15 +2289,18 @@ ConstantLValueEmitter::VisitMaterializeTemporaryExpr(
return CGM.GetAddrOfGlobalTemporary(E, Inner);
}
-llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
- QualType DestType) {
+llvm::Constant *
+ConstantEmitter::tryEmitPrivate(const APValue &Value, QualType DestType,
+ bool EnablePtrAuthFunctionTypeDiscrimination) {
switch (Value.getKind()) {
case APValue::None:
case APValue::Indeterminate:
// Out-of-lifetime and indeterminate values can be modeled as 'undef'.
return llvm::UndefValue::get(CGM.getTypes().ConvertType(DestType));
case APValue::LValue:
- return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
+ return ConstantLValueEmitter(*this, Value, DestType,
+ EnablePtrAuthFunctionTypeDiscrimination)
+ .tryEmit();
case APValue::Int:
return llvm::ConstantInt::get(CGM.getLLVMContext(), Value.getInt());
case APValue::FixedPoint:
diff --git a/clang/lib/CodeGen/CGPointerAuth.cpp b/clang/lib/CodeGen/CGPointerAuth.cpp
index 673f6e60bfc31..621d567dde721 100644
--- a/clang/lib/CodeGen/CGPointerAuth.cpp
+++ b/clang/lib/CodeGen/CGPointerAuth.cpp
@@ -29,7 +29,9 @@ llvm::ConstantInt *CodeGenModule::getPointerAuthOtherDiscriminator(
return nullptr;
case PointerAuthSchema::Discrimination::Type:
- llvm_unreachable("type discrimination not implemented yet");
+ assert(!Type.isNull() && "type not provided for type-discriminated schema");
+ return llvm::ConstantInt::get(
+ IntPtrTy, getContext().getPointerAuthTypeDiscriminator(Type));
case PointerAuthSchema::Discrimination::Decl:
assert(Decl.getDecl() &&
@@ -43,6 +45,11 @@ llvm::ConstantInt *CodeGenModule::getPointerAuthOtherDiscriminator(
llvm_unreachable("bad discrimination kind");
}
+uint16_t CodeGen::getPointerAuthTypeDiscriminator(CodeGenModule &CGM,
+ QualType FunctionType) {
+ return CGM.getContext().getPointerAuthTypeDiscriminator(FunctionType);
+}
+
uint16_t CodeGen::getPointerAuthDeclDiscriminator(CodeGenModule &CGM,
GlobalDecl Declaration) {
return CGM.getPointerAuthDeclDiscriminator(Declaration);
@@ -71,12 +78,15 @@ CGPointerAuthInfo CodeGenModule::getFunctionPointerAuthInfo(QualType T) {
assert(!Schema.isAddressDiscriminated() &&
"function pointers cannot use address-specific discrimination");
- assert(!Schema.hasOtherDiscrimination() &&
- "function pointers don't support any discrimination yet");
+ llvm::Constant *Discriminator = nullptr;
+ if (T->isFunctionPointerType() || T->isFunctionReferenceType())
+ T = T->getPointeeType();
+ if (T->isFunctionType())
+ Discriminator = getPointerAuthOtherDiscriminator(Schema, GlobalDecl(), T);
return CGPointerAuthInfo(Schema.getKey(), Schema.getAuthenticationMode(),
/*IsaPointer=*/false, /*AuthenticatesNull=*/false,
- /*Discriminator=*/nullptr);
+ Discriminator);
}
llvm::Value *
@@ -114,6 +124,47 @@ CGPointerAuthInfo CodeGenFunction::EmitPointerAuthInfo(
Schema.authenticatesNullValues(), Discriminator);
}
+/// Return the natural pointer authentication for values of the given
+/// pointee type.
+static CGPointerAuthInfo
+getPointerAuthInfoForPointeeType(CodeGenModule &CGM, QualType PointeeType) {
+ if (PointeeType.isNull())
+ return CGPointerAuthInfo();
+
+ // Function pointers use the function-pointer schema by default.
+ if (PointeeType->isFunctionType())
+ return CGM.getFunctionPointerAuthInfo(PointeeType);
+
+ // Normal data pointers never use direct pointer authentication by default.
+ return CGPointerAuthInfo();
+}
+
+CGPointerAuthInfo CodeGenModule::getPointerAuthInfoForPointeeType(QualType T) {
+ return ::getPointerAuthInfoForPointeeType(*this, T);
+}
+
+/// Return the natural pointer authentication for values of the given
+/// pointer type.
+static CGPointerAuthInfo getPointerAuthInfoForType(CodeGenModule &CGM,
+ QualType PointerType) {
+ assert(PointerType->isSignableType());
+
+ // Block pointers are currently not signed.
+ if (PointerType->isBlockPointerType())
+ return CGPointerAuthInfo();
+
+ auto PointeeType = PointerType->getPointeeType();
+
+ if (PointeeType.isNull())
+ return CGPointerAuthInfo();
+
+ return ::getPointerAuthInfoForPointeeType(CGM, PointeeType);
+}
+
+CGPointerAuthInfo CodeGenModule::getPointerAuthInfoForType(QualType T) {
+ return ::getPointerAuthInfoForType(*this, T);
+}
+
llvm::Constant *
CodeGenModule::getConstantSignedPointer(llvm::Constant *Pointer, unsigned Key,
llvm::Constant *StorageAddress,
@@ -180,6 +231,14 @@ llvm::Constant *CodeGenModule::getFunctionPointer(GlobalDecl GD,
llvm::Type *Ty) {
const auto *FD = cast<FunctionDecl>(GD.getDecl());
QualType FuncType = FD->getType();
+
+ // Annoyingly, K&R functions have prototypes in the clang AST, but
+ // expressions referring to them are unprototyped.
+ if (!FD->hasPrototype())
+ if (const auto *Proto = FuncType->getAs<FunctionProtoType>())
+ FuncType = Context.getFunctionNoProtoType(Proto->getReturnType(),
+ Proto->getExtInfo());
+
return getFunctionPointer(getRawFunctionPointer(GD, Ty), FuncType);
}
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 8b65348b879b6..585c4ea697fea 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -972,6 +972,10 @@ class CodeGenModule : public CodeGenTypeCache {
CGPointerAuthInfo getFunctionPointerAuthInfo(QualType T);
+ CGPointerAuthInfo getPointerAuthInfoForPointeeType(QualType type);
+
+ CGPointerAuthInfo getPointerAuthInfoForType(QualType type);
+
bool shouldSignPointer(const PointerAuthSchema &Schema);
llvm::Constant *getConstantSignedPointer(llvm::Constant *Pointer,
const PointerAuthSchema &Schema,
diff --git a/clang/lib/CodeGen/ConstantEmitter.h b/clang/lib/CodeGen/ConstantEmitter.h
index eff0a8d52891f..581b05ae87add 100644
--- a/clang/lib/CodeGen/ConstantEmitter.h
+++ b/clang/lib/CodeGen/ConstantEmitter.h
@@ -103,8 +103,9 @@ class ConstantEmitter {
/// expression is known to be a constant expression with either a fairly
/// simple type or a known simple form.
llvm::Constant *emitAbstract(const Expr *E, QualType T);
- llvm::Constant *emitAbstract(SourceLocation loc, const APValue &value,
- QualType T);
+ llvm::Constant *
+ emitAbstract(SourceLocation loc, const APValue &value, QualType T,
+ bool EnablePtrAuthFunctionTypeDiscrimination = true);
/// Try to emit the result of the given expression as an abstract constant.
llvm::Constant *tryEmitAbstract(const Expr *E, QualType T);
@@ -138,7 +139,9 @@ class ConstantEmitter {
llvm::Constant *tryEmitPrivate(const Expr *E, QualType T);
llvm::Constant *tryEmitPrivateForMemory(const Expr *E, QualType T);
- llvm::Constant *tryEmitPrivate(const APValue &value, QualType T);
+ llvm::Constant *
+ tryEmitPrivate(const APValue &value, QualType T,
+ bool EnablePtrAuthFunctionTypeDiscrimination = true);
llvm::Constant *tryEmitPrivateForMemory(const APValue &value, QualType T);
/// Get the address of the current location. This is a constant
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index edb3c20ec9768..4a674f67b8e1b 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1789,6 +1789,9 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
options::OPT_fno_ptrauth_vtable_pointer_type_discrimination);
Args.addOptInFlag(CmdArgs, options::OPT_fptrauth_init_fini,
options::OPT_fno_ptrauth_init_fini);
+ Args.addOptInFlag(
+ CmdArgs, options::OPT_fptrauth_function_pointer_type_discrimination,
+ options::OPT_fno_ptrauth_function_pointer_type_discrimination);
}
void Clang::AddLoongArchTargetArgs(const ArgList &Args,
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 0082c15aac7e4..bf57addff1c6d 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1479,8 +1479,10 @@ void CompilerInvocation::setDefaultPointerAuthOptions(
using Key = PointerAuthSchema::ARM8_3Key;
using Discrimination = PointerAuthSchema::Discrimination;
// If you change anything here, be sure to update <ptrauth.h>.
- Opts.FunctionPointers =
- PointerAuthSchema(Key::ASIA, false, Discrimination::None);
+ Opts.FunctionPointers = PointerAuthSchema(
+ Key::ASIA, false,
+ LangOpts.PointerAuthFunctionTypeDiscrimination ? Discrimination::Type
+ : Discrimination::None);
Opts.CXXVTablePointers = PointerAuthSchema(
Key::ASDA, LangOpts.PointerAuthVTPtrAddressDiscrimination,
@@ -3411,6 +3413,8 @@ static void GeneratePointerAuthArgs(const LangOptions &Opts,
GenerateArg(Consumer, OPT_fptrauth_vtable_pointer_type_discrimination);
if (Opts.PointerAuthInitFini)
GenerateArg(Consumer, OPT_fptrauth_init_fini);
+ if (Opts.PointerAuthFunctionTypeDiscrimination)
+ GenerateArg(Consumer, OPT_fptrauth_function_pointer_type_discrimination);
}
static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args,
@@ -3424,6 +3428,8 @@ static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args,
Opts.PointerAuthVTPtrTypeDiscrimination =
Args.hasArg(OPT_fptrauth_vtable_pointer_type_discrimination);
Opts.PointerAuthInitFini = Args.hasArg(OPT_fptrauth_init_fini);
+ Opts.PointerAuthFunctionTypeDiscrimination =
+ Args.hasArg(OPT_fptrauth_function_pointer_type_discrimination);
}
/// Check if input file kind and language standard are compatible.
diff --git a/clang/test/CodeGen/ptrauth-function-type-discriminator.c b/clang/test/CodeGen/ptrauth-function-type-discriminator.c
new file mode 100644
index 0000000000000..5dea48fe5915b
--- /dev/null
+++ b/clang/test/CodeGen/ptrauth-function-type-discriminator.c
@@ -0,0 +1,137 @@
+// RUN: %clang_cc1 %s -fptrauth-function-pointer-type-discrimination -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics -disable-llvm-passes -emit-llvm -o- | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKC
+// RUN: %clang_cc1 -xc++ %s -fptrauth-function-pointer-type-discrimination -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics -disable-llvm-passes -emit-llvm -o- | FileCheck %s --check-prefix=CHECK
+// RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics -emit-pch %s -o %t.ast
+// RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64-apple-ios -fptrauth-calls -fptrauth-intrinsics -emit-llvm -x ast -o - %t.ast | FileCheck -check-prefix=CHECK --check-prefix=CHECKC %s
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void f(void);
+void f2(int);
+void (*fnptr)(void);
+void *opaque;
+unsigned long uintptr;
+
+// CHECK: @test_constant_null = global ptr null
+void (*test_constant_null)(int) = 0;
+
+// CHECK: @test_constant_cast = global ptr ptrauth (ptr @f, i32 0, i64 2712)
+void (*test_constant_cast)(int) = (void (*)(int))f;
+
+// CHECK: @test_opaque = global ptr ptrauth (ptr @f, i32 0)
+void *test_opaque =
+#ifdef __cplusplus
+ (void *)
+#endif
+ (void (*)(int))(double (*)(double))f;
+
+// CHECK: @test_intptr_t = global i64 ptrtoint (ptr ptrauth (ptr @f, i32 0) to i64)
+unsigned long test_intptr_t = (unsigned long)f;
+
+// CHECK: @test_through_long = global ptr ptrauth (ptr @f, i32 0, i64 2712)
+void (*test_through_long)(int) = (void (*)(int))(long)f;
+
+// CHECK: @test_to_long = global i64 ptrtoint (ptr ptrauth (ptr @f, i32 0) to i64)
+long test_to_long = (long)(double (*)())f;
+
+extern void external_function(void);
+// CHECK: @fptr1 = global ptr ptrauth (ptr @external_function, i32 0, i64 18983)
+void (*fptr1)(void) = external_function;
+// CHECK: @fptr2 = global ptr ptrauth (ptr @external_function, i32 0, i64 18983)
+void (*fptr2)(void) = &external_function;
+
+// CHECK: @fptr3 = global ptr ptrauth (ptr @external_function, i32 2, i64 26)
+void (*fptr3)(void) = __builtin_ptrauth_sign_constant(&external_function, 2, 26);
+
+// CHECK: @fptr4 = global ptr ptrauth (ptr @external_function, i32 2, i64 26, ptr @fptr4)
+void (*fptr4)(void) = __builtin_ptrauth_sign_constant(&external_function, 2, __builtin_ptrauth_blend_discriminator(&fptr4, 26));
+
+// CHECK-LABEL: define void @test_call()
+void test_call() {
+ // CHECK: [[T0:%.*]] = load ptr, ptr @fnptr,
+ // CHECK-NEXT: call void [[T0]]() [ "ptrauth"(i32 0, i64 18983) ]
+ fnptr();
+}
+
+// CHECK-LABEL: define ptr @test_function_pointer()
+// CHECK: ret ptr ptrauth (ptr @external_function, i32 0, i64 18983)
+void (*test_function_pointer())(void) {
+ return external_function;
+}
+
+struct InitiallyIncomplete;
+extern struct InitiallyIncomplete returns_initially_incomplete(void);
+// CHECK-LABEL: define void @use_while_incomplete()
+void use_while_incomplete() {
+ // CHECK: [[VAR:%.*]] = alloca ptr,
+ // CHECK-NEXT: store ptr ptrauth (ptr @returns_initially_incomplete, i32 0, i64 25106), ptr [[VAR]]
+ struct InitiallyIncomplete (*fnptr)(void) = &returns_initially_incomplete;
+}
+struct InitiallyIncomplete { int x; };
+// CHECK-LABEL: define void @use_while_complete()
+void use_while_complete() {
+ // CHECK: [[VAR:%.*]] = alloca ptr,
+ // CHECK-NEXT: store ptr ptrauth (ptr @returns_initially_incomplete, i32 0, i64 25106), ptr [[VAR]]
+ // CHECK-NEXT: ret void
+ struct InitiallyIncomplete (*fnptr)(void) = &returns_initially_incomplete;
+}
+
+#ifndef __cplusplus
+
+void knr(param)
+ int param;
+{}
+
+// CHECKC-LABEL: define void @test_knr
+void test_knr() {
+ void (*p)() = knr;
+ p(0);
+
+ // CHECKC: [[P:%.*]] = alloca ptr
+ // CHECKC: store ptr ptrauth (ptr @knr, i32 0, i64 18983), ptr [[P]]
+ // CHECKC: [[LOAD:%.*]] = load ptr, ptr [[P]]
+ // CHECKC: call void [[LOAD]](i32 noundef 0) [ "ptrauth"(i32 0, i64 18983) ]
+}
+
+// CHECKC-LABEL: define void @test_redeclaration
+void test_redeclaration() {
+ void redecl();
+ void (*ptr)() = redecl;
+ void redecl(int);
+ void (*ptr2)(int) = redecl;
+ ptr();
+ ptr2(0);
+
+ // CHECKC: store ptr ptrauth (ptr @redecl, i32 0, i64 18983), ptr %ptr
+ // CHECKC: store ptr ptrauth (ptr @redecl, i32 0, i64 2712), ptr %ptr2
+ // CHECKC: call void {{.*}}() [ "ptrauth"(i32 0, i64 18983) ]
+ // CHECKC: call void {{.*}}(i32 noundef 0) [ "ptrauth"(i32 0, i64 2712) ]
+}
+
+void knr2(param)
+ int param;
+{}
+
+// CHECKC-LABEL: define void @test_redecl_knr
+void test_redecl_knr() {
+ void (*p)() = knr2;
+ p();
+
+ // CHECKC: store ptr ptrauth (ptr @knr2, i32 0, i64 18983)
+ // CHECKC: call void {{.*}}() [ "ptrauth"(i32 0, i64 18983) ]
+
+ void knr2(int);
+
+ void (*p2)(int) = knr2;
+ p2(0);
+
+ // CHECKC: store ptr ptrauth (ptr @knr2, i32 0, i64 2712)
+ // CHECKC: call void {{.*}}(i32 noundef 0) [ "ptrauth"(i32 0, i64 2712) ]
+}
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/clang/test/Preprocessor/ptrauth_feature.c b/clang/test/Preprocessor/ptrauth_feature.c
index 80e239110ffc7..88b6982c01657 100644
--- a/clang/test/Preprocessor/ptrauth_feature.c
+++ b/clang/test/Preprocessor/ptrauth_feature.c
@@ -5,7 +5,7 @@
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-init-fini | \
-// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI
+// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI,NOFUNC
// RUN: %clang_cc1 -E %s -triple=aarch64 \
// RUN: -fptrauth-calls \
@@ -13,7 +13,7 @@
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-init-fini | \
-// RUN: FileCheck %s --check-prefixes=NOINTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI
+// RUN: FileCheck %s --check-prefixes=NOINTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI,NOFUNC
// RUN: %clang_cc1 -E %s -triple=aarch64 \
// RUN: -fptrauth-intrinsics \
@@ -21,7 +21,7 @@
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-init-fini | \
-// RUN: FileCheck %s --check-prefixes=INTRIN,NOCALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI
+// RUN: FileCheck %s --check-prefixes=INTRIN,NOCALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI,NOFUNC
// RUN: %clang_cc1 -E %s -triple=aarch64 \
// RUN: -fptrauth-intrinsics \
@@ -29,7 +29,7 @@
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-init-fini | \
-// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,NORETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI
+// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,NORETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI,NOFUNC
// RUN: %clang_cc1 -E %s -triple=aarch64 \
// RUN: -fptrauth-intrinsics \
@@ -37,7 +37,7 @@
// RUN: -fptrauth-returns \
// RUN: -fptrauth-vtable-pointer-type-discrimination \
// RUN: -fptrauth-init-fini | \
-// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,NOVPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI
+// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,NOVPTR_ADDR_DISCR,VPTR_TYPE_DISCR,INITFINI,NOFUNC
// RUN: %clang_cc1 -E %s -triple=aarch64 \
// RUN: -fptrauth-intrinsics \
@@ -45,7 +45,7 @@
// RUN: -fptrauth-returns \
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -fptrauth-init-fini | \
-// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,NOVPTR_TYPE_DISCR,INITFINI
+// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,NOVPTR_TYPE_DISCR,INITFINI,NOFUNC
// RUN: %clang_cc1 -E %s -triple=aarch64 \
// RUN: -fptrauth-intrinsics \
@@ -53,7 +53,17 @@
// RUN: -fptrauth-returns \
// RUN: -fptrauth-vtable-pointer-address-discrimination \
// RUN: -fptrauth-vtable-pointer-type-discrimination | \
-// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,NOINITFINI
+// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,NOINITFINI,NOFUNC
+
+// RUN: %clang_cc1 -E %s -triple=aarch64 \
+// RUN: -fptrauth-intrinsics \
+// RUN: -fptrauth-calls \
+// RUN: -fptrauth-returns \
+// RUN: -fptrauth-vtable-pointer-address-discrimination \
+// RUN: -fptrauth-vtable-pointer-type-discrimination \
+// RUN: -fptrauth-function-pointer-type-discrimination | \
+// RUN: FileCheck %s --check-prefixes=INTRIN,CALLS,RETS,VPTR_ADDR_DISCR,VPTR_TYPE_DISCR,NOINITFINI,FUNC
+
#if __has_feature(ptrauth_intrinsics)
// INTRIN: has_ptrauth_intrinsics
@@ -111,3 +121,13 @@ void has_ptrauth_init_fini() {}
// NOINITFINI: no_ptrauth_init_fini
void no_ptrauth_init_fini() {}
#endif
+
+#include <ptrauth.h>
+
+#if __has_feature(ptrauth_function_pointer_type_discrimination)
+// FUNC: has_ptrauth_function_pointer_type_discrimination
+void has_ptrauth_function_pointer_type_discrimination() {}
+#else
+// NOFUNC: no_ptrauth_function_pointer_type_discrimination
+void no_ptrauth_function_pointer_type_discrimination() {}
+#endif
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