[clang] Implement pointer authentication for C++ virtual functions, v-tables, and VTTs #94054
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…created. Co-Authored-By: John McCall <rjmccall@apple.com>
…-tables, and VTTs. This also implements the ptrauth_vtable_pointer attribute to allow overriding the default ptrauth schema for vtable pointers. Co-Authored-By: John McCall <rjmccall@apple.com>
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@llvm/pr-subscribers-backend-x86 @llvm/pr-subscribers-clang-codegen Author: Oliver Hunt (ojhunt) ChangesPatch is 245.54 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/94054.diff 53 Files Affected:
diff --git a/clang/include/clang/AST/ASTContext.h b/clang/include/clang/AST/ASTContext.h
index a1d1d1c51cd41..e601face9c2b6 100644
--- a/clang/include/clang/AST/ASTContext.h
+++ b/clang/include/clang/AST/ASTContext.h
@@ -37,6 +37,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/Support/TypeSize.h"
#include <optional>
@@ -1261,6 +1262,10 @@ class ASTContext : public RefCountedBase<ASTContext> {
/// space.
QualType removeAddrSpaceQualType(QualType T) const;
+ /// Return the "other" type-specific discriminator for the given type.
+ uint16_t
+ getPointerAuthVTablePointerDiscriminator(const CXXRecordDecl *record);
+
/// 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
@@ -3418,12 +3423,20 @@ OPT_LIST(V)
/// Whether a C++ static variable or CUDA/HIP kernel should be externalized.
bool shouldExternalize(const Decl *D) const;
+ /// Resolve the root record to be used to derive the vtable pointer
+ /// authentication policy for the specified record.
+ const CXXRecordDecl *baseForVTableAuthentication(const CXXRecordDecl *);
+ bool useAbbreviatedThunkName(GlobalDecl virtualMethodDecl,
+ StringRef mangledName);
+
StringRef getCUIDHash() const;
private:
/// All OMPTraitInfo objects live in this collection, one per
/// `pragma omp [begin] declare variant` directive.
SmallVector<std::unique_ptr<OMPTraitInfo>, 4> OMPTraitInfoVector;
+
+ llvm::DenseMap<GlobalDecl, llvm::StringSet<>> thunksToBeAbbreviated;
};
/// Insertion operator for diagnostics.
diff --git a/clang/include/clang/AST/GlobalDecl.h b/clang/include/clang/AST/GlobalDecl.h
index 88abba28c991d..386693cabb1fb 100644
--- a/clang/include/clang/AST/GlobalDecl.h
+++ b/clang/include/clang/AST/GlobalDecl.h
@@ -145,6 +145,10 @@ class GlobalDecl {
LHS.MultiVersionIndex == RHS.MultiVersionIndex;
}
+ bool operator!=(const GlobalDecl &Other) const {
+ return !(*this == Other);
+ }
+
void *getAsOpaquePtr() const { return Value.getOpaqueValue(); }
explicit operator bool() const { return getAsOpaquePtr(); }
diff --git a/clang/include/clang/AST/Mangle.h b/clang/include/clang/AST/Mangle.h
index e586b0cec43df..d83d56cf42c72 100644
--- a/clang/include/clang/AST/Mangle.h
+++ b/clang/include/clang/AST/Mangle.h
@@ -130,15 +130,15 @@ class MangleContext {
// FIXME: consider replacing raw_ostream & with something like SmallString &.
void mangleName(GlobalDecl GD, raw_ostream &);
virtual void mangleCXXName(GlobalDecl GD, raw_ostream &) = 0;
- virtual void mangleThunk(const CXXMethodDecl *MD,
- const ThunkInfo &Thunk,
- raw_ostream &) = 0;
+ virtual void mangleThunk(const CXXMethodDecl *MD, const ThunkInfo &Thunk,
+ bool elideOverrideInfo, raw_ostream &) = 0;
virtual void mangleCXXDtorThunk(const CXXDestructorDecl *DD, CXXDtorType Type,
- const ThisAdjustment &ThisAdjustment,
- raw_ostream &) = 0;
+ const ThunkInfo &Thunk,
+ bool elideOverrideInfo, raw_ostream &) = 0;
virtual void mangleReferenceTemporary(const VarDecl *D,
unsigned ManglingNumber,
raw_ostream &) = 0;
+ virtual void mangleCXXVTable(const CXXRecordDecl *RD, raw_ostream &) = 0;
virtual void mangleCXXRTTI(QualType T, raw_ostream &) = 0;
virtual void mangleCXXRTTIName(QualType T, raw_ostream &,
bool NormalizeIntegers = false) = 0;
@@ -192,7 +192,6 @@ class ItaniumMangleContext : public MangleContext {
bool IsAux = false)
: MangleContext(C, D, MK_Itanium, IsAux) {}
- virtual void mangleCXXVTable(const CXXRecordDecl *RD, raw_ostream &) = 0;
virtual void mangleCXXVTT(const CXXRecordDecl *RD, raw_ostream &) = 0;
virtual void mangleCXXCtorVTable(const CXXRecordDecl *RD, int64_t Offset,
const CXXRecordDecl *Type,
diff --git a/clang/include/clang/AST/VTableBuilder.h b/clang/include/clang/AST/VTableBuilder.h
index fbf6c041a1ec1..a5de41dbc22f1 100644
--- a/clang/include/clang/AST/VTableBuilder.h
+++ b/clang/include/clang/AST/VTableBuilder.h
@@ -361,6 +361,10 @@ class VTableContextBase {
};
class ItaniumVTableContext : public VTableContextBase {
+public:
+ typedef llvm::DenseMap<const CXXMethodDecl *, const CXXMethodDecl *>
+ OriginalMethodMapTy;
+
private:
/// Contains the index (relative to the vtable address point)
@@ -384,6 +388,10 @@ class ItaniumVTableContext : public VTableContextBase {
VirtualBaseClassOffsetOffsetsMapTy;
VirtualBaseClassOffsetOffsetsMapTy VirtualBaseClassOffsetOffsets;
+ /// Map from a virtual method to the nearest method in the primary base class
+ /// chain that it overrides.
+ OriginalMethodMapTy OriginalMethodMap;
+
void computeVTableRelatedInformation(const CXXRecordDecl *RD) override;
public:
@@ -425,6 +433,27 @@ class ItaniumVTableContext : public VTableContextBase {
CharUnits getVirtualBaseOffsetOffset(const CXXRecordDecl *RD,
const CXXRecordDecl *VBase);
+ /// Return the method that added the v-table slot that will be used to call
+ /// the given method.
+ ///
+ /// In the Itanium ABI, where overrides always cause methods to be added to
+ /// the primary v-table if they're not already there, this will be the first
+ /// declaration in the primary base class chain for which the return type
+ /// adjustment is trivial.
+ GlobalDecl findOriginalMethod(GlobalDecl GD);
+
+ const CXXMethodDecl *findOriginalMethodInMap(const CXXMethodDecl *MD) const;
+
+ void setOriginalMethod(const CXXMethodDecl *Key, const CXXMethodDecl *Val) {
+ OriginalMethodMap[Key] = Val;
+ }
+
+ /// This method is reserved for the implementation and shouldn't be used
+ /// directly.
+ const OriginalMethodMapTy &getOriginalMethodMap() {
+ return OriginalMethodMap;
+ }
+
static bool classof(const VTableContextBase *VT) {
return !VT->isMicrosoft();
}
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index ef9df1e9d8b4a..191afdc147f40 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -680,6 +680,10 @@ class Attr {
bit PragmaAttributeSupport;
// Set to true if this attribute accepts parameter pack expansion expressions.
bit AcceptsExprPack = 0;
+ // To support multiple enum parameters to an attribute without breaking
+ // our existing general parsing we need to have a separate flag that
+ // opts an attribute into strict parsing of attribute parameters
+ bit StrictEnumParameters = 0;
// Lists language options, one of which is required to be true for the
// attribute to be applicable. If empty, no language options are required.
list<LangOpt> LangOpts = [];
@@ -4546,6 +4550,31 @@ def NoRandomizeLayout : InheritableAttr {
}
def : MutualExclusions<[RandomizeLayout, NoRandomizeLayout]>;
+def VTablePointerAuthentication : InheritableAttr {
+ let Spellings = [Clang<"ptrauth_vtable_pointer">];
+ let Subjects = SubjectList<[CXXRecord]>;
+ let Documentation = [Undocumented];
+ let StrictEnumParameters = 1;
+ let Args = [EnumArgument<"Key", "VPtrAuthKeyType", /*is_string=*/ true,
+ ["default_key", "no_authentication", "process_dependent",
+ "process_independent"],
+ ["DefaultKey", "NoKey", "ProcessDependent",
+ "ProcessIndependent"]>,
+ EnumArgument<"AddressDiscrimination", "AddressDiscriminationMode",
+ /*is_string=*/ true,
+ ["default_address_discrimination", "no_address_discrimination",
+ "address_discrimination"],
+ ["DefaultAddressDiscrimination", "NoAddressDiscrimination",
+ "AddressDiscrimination"]>,
+ EnumArgument<"ExtraDiscrimination", "ExtraDiscrimination",
+ /*is_string=*/ true,
+ ["default_extra_discrimination", "no_extra_discrimination",
+ "type_discrimination", "custom_discrimination"],
+ ["DefaultExtraDiscrimination", "NoExtraDiscrimination",
+ "TypeDiscrimination", "CustomDiscrimination"]>,
+ IntArgument<"CustomDiscriminationValue", 1>];
+}
+
def FunctionReturnThunks : InheritableAttr,
TargetSpecificAttr<TargetAnyX86> {
let Spellings = [GCC<"function_return">];
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 753e775ce0968..88b8fd344648b 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -938,6 +938,13 @@ def warn_ptrauth_auth_null_pointer :
def err_ptrauth_string_not_literal : Error<
"argument must be a string literal%select{| of char type}0">;
+def note_ptrauth_virtual_function_pointer_incomplete_arg_ret :
+ Note<"cannot take an address of a virtual member function if its return or "
+ "argument types are incomplete">;
+def note_ptrauth_virtual_function_incomplete_arg_ret_type :
+ Note<"%0 is incomplete">;
+
+
/// main()
// static main() is not an error in C, just in C++.
def warn_static_main : Warning<"'main' should not be declared static">,
@@ -12175,6 +12182,30 @@ def warn_cuda_maxclusterrank_sm_90 : Warning<
"maxclusterrank requires sm_90 or higher, CUDA arch provided: %0, ignoring "
"%1 attribute">, InGroup<IgnoredAttributes>;
+// VTable pointer authentication errors
+def err_non_polymorphic_vtable_pointer_auth : Error<
+ "cannot set vtable pointer authentication on monomorphic type %0">;
+def err_incomplete_type_vtable_pointer_auth : Error<
+ "cannot set vtable pointer authentication on an incomplete type %0">;
+def err_non_top_level_vtable_pointer_auth : Error<
+ "cannot set vtable pointer authentication on %0 which is a subclass of polymorphic type %1">;
+def err_duplicated_vtable_pointer_auth : Error<
+ "multiple vtable pointer authentication policies on %0">;
+def err_invalid_authentication_key : Error<
+ "invalid authentication key %0">;
+def err_invalid_address_discrimination : Error<
+ "invalid address discrimination mode %0">;
+def err_invalid_extra_discrimination : Error<
+ "invalid extra discrimination selection %0">;
+def err_invalid_custom_discrimination : Error<
+ "invalid custom discrimination">;
+def err_missing_custom_discrimination : Error<
+ "missing custom discrimination">;
+def err_no_default_vtable_pointer_auth : Error<
+ "cannot specify a default vtable pointer authentication "
+ "%select{key|address discrimination mode|discriminator}0 with no default set"
+>;
+
def err_bit_int_bad_size : Error<"%select{signed|unsigned}0 _BitInt must "
"have a bit size of at least %select{2|1}0">;
def err_bit_int_max_size : Error<"%select{signed|unsigned}0 _BitInt of bit "
diff --git a/clang/include/clang/Basic/PointerAuthOptions.h b/clang/include/clang/Basic/PointerAuthOptions.h
index 32b179e3f9460..d4d794a6fabe0 100644
--- a/clang/include/clang/Basic/PointerAuthOptions.h
+++ b/clang/include/clang/Basic/PointerAuthOptions.h
@@ -49,6 +49,12 @@ class PointerAuthSchema {
/// No additional discrimination.
None,
+ /// Include a hash of the entity's type.
+ Type,
+
+ /// Include a hash of the entity's identity.
+ Decl,
+
/// Discriminate using a constant value.
Constant,
};
@@ -152,6 +158,25 @@ class PointerAuthSchema {
struct PointerAuthOptions {
/// The ABI for C function pointers.
PointerAuthSchema FunctionPointers;
+
+ /// The ABI for C++ virtual table pointers (the pointer to the table
+ /// itself) as installed in an actual class instance.
+ PointerAuthSchema CXXVTablePointers;
+
+ /// TypeInfo has external ABI requirements and is emitted without
+ /// actually having parsed the libcxx definition, so we can't simply
+ /// perform a look up. The settings for this should match the exact
+ /// specification in type_info.h
+ PointerAuthSchema CXXTypeInfoVTablePointer;
+
+ /// The ABI for C++ virtual table pointers as installed in a VTT.
+ PointerAuthSchema CXXVTTVTablePointers;
+
+ /// The ABI for most C++ virtual function pointers, i.e. v-table entries.
+ PointerAuthSchema CXXVirtualFunctionPointers;
+
+ /// The ABI for variadic C++ virtual function pointers.
+ PointerAuthSchema CXXVirtualVariadicFunctionPointers;
};
} // end namespace clang
diff --git a/clang/include/clang/Basic/Thunk.h b/clang/include/clang/Basic/Thunk.h
index 0247e279408f0..4dccebf687585 100644
--- a/clang/include/clang/Basic/Thunk.h
+++ b/clang/include/clang/Basic/Thunk.h
@@ -162,20 +162,27 @@ struct ThunkInfo {
/// Holds a pointer to the overridden method this thunk is for,
/// if needed by the ABI to distinguish different thunks with equal
- /// adjustments. Otherwise, null.
+ /// adjustments.
+ /// In the Itanium ABI, this field can hold the method that created the
+ /// vtable entry for this thunk.
+ /// Otherwise, null.
/// CAUTION: In the unlikely event you need to sort ThunkInfos, consider using
/// an ABI-specific comparator.
const CXXMethodDecl *Method;
+ const Type *ThisType { nullptr };
ThunkInfo() : Method(nullptr) {}
ThunkInfo(const ThisAdjustment &This, const ReturnAdjustment &Return,
+ const Type *thisType,
const CXXMethodDecl *Method = nullptr)
- : This(This), Return(Return), Method(Method) {}
+ : This(This), Return(Return), Method(Method),
+ ThisType(thisType) {}
friend bool operator==(const ThunkInfo &LHS, const ThunkInfo &RHS) {
return LHS.This == RHS.This && LHS.Return == RHS.Return &&
- LHS.Method == RHS.Method;
+ LHS.Method == RHS.Method &&
+ LHS.ThisType == RHS.ThisType;
}
bool isEmpty() const {
diff --git a/clang/include/clang/CodeGen/CodeGenABITypes.h b/clang/include/clang/CodeGen/CodeGenABITypes.h
index 8c62d8597ecbe..0d0c152c6fea0 100644
--- a/clang/include/clang/CodeGen/CodeGenABITypes.h
+++ b/clang/include/clang/CodeGen/CodeGenABITypes.h
@@ -42,6 +42,7 @@ class CXXConstructorDecl;
class CXXDestructorDecl;
class CXXRecordDecl;
class CXXMethodDecl;
+class GlobalDecl;
class ObjCMethodDecl;
class ObjCProtocolDecl;
@@ -104,6 +105,9 @@ llvm::Type *convertTypeForMemory(CodeGenModule &CGM, QualType T);
unsigned getLLVMFieldNumber(CodeGenModule &CGM,
const RecordDecl *RD, const FieldDecl *FD);
+/// Return a declaration discriminator for the given global decl.
+uint16_t getPointerAuthDeclDiscriminator(CodeGenModule &CGM, GlobalDecl GD);
+
/// Return a signed constant pointer.
llvm::Constant *getConstantSignedPointer(CodeGenModule &CGM,
llvm::Constant *pointer,
diff --git a/clang/include/clang/CodeGen/ConstantInitBuilder.h b/clang/include/clang/CodeGen/ConstantInitBuilder.h
index 498acfd380131..f6d8e15ff2131 100644
--- a/clang/include/clang/CodeGen/ConstantInitBuilder.h
+++ b/clang/include/clang/CodeGen/ConstantInitBuilder.h
@@ -25,8 +25,11 @@
#include <vector>
namespace clang {
-namespace CodeGen {
+class GlobalDecl;
+class PointerAuthSchema;
+class QualType;
+namespace CodeGen {
class CodeGenModule;
/// A convenience builder class for complex constant initializers,
@@ -199,6 +202,17 @@ class ConstantAggregateBuilderBase {
add(llvm::ConstantInt::get(intTy, value, isSigned));
}
+ /// Add a signed pointer using the given pointer authentication schema.
+ void addSignedPointer(llvm::Constant *pointer,
+ const PointerAuthSchema &schema, GlobalDecl calleeDecl,
+ QualType calleeType);
+
+ /// Add a signed pointer using the given pointer authentication schema.
+ void addSignedPointer(llvm::Constant *pointer,
+ unsigned key,
+ bool useAddressDiscrimination,
+ llvm::Constant *otherDiscriminator);
+
/// Add a null pointer of a specific type.
void addNullPointer(llvm::PointerType *ptrTy) {
add(llvm::ConstantPointerNull::get(ptrTy));
diff --git a/clang/include/clang/InstallAPI/Visitor.h b/clang/include/clang/InstallAPI/Visitor.h
index 9ac948ded3e33..3680ee566ca87 100644
--- a/clang/include/clang/InstallAPI/Visitor.h
+++ b/clang/include/clang/InstallAPI/Visitor.h
@@ -60,8 +60,8 @@ class InstallAPIVisitor final : public ASTConsumer,
std::string getMangledName(const NamedDecl *D) const;
std::string getBackendMangledName(llvm::Twine Name) const;
std::string getMangledCXXVTableName(const CXXRecordDecl *D) const;
- std::string getMangledCXXThunk(const GlobalDecl &D,
- const ThunkInfo &Thunk) const;
+ std::string getMangledCXXThunk(const GlobalDecl &D, const ThunkInfo &Thunk,
+ bool ElideOverrideInfo) const;
std::string getMangledCXXRTTI(const CXXRecordDecl *D) const;
std::string getMangledCXXRTTIName(const CXXRecordDecl *D) const;
std::string getMangledCtorDtor(const CXXMethodDecl *D, int Type) const;
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index ec083f7cc09b7..dd65662e77860 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -4401,6 +4401,10 @@ class Sema final : public SemaBase {
/// conditions that are needed for the attribute to have an effect.
void checkIllFormedTrivialABIStruct(CXXRecordDecl &RD);
+ /// Check that VTable Pointer authentication is only being set on the first
+ /// first instantiation of the vtable
+ void checkIncorrectVTablePointerAuthenticationAttribute(CXXRecordDecl &RD);
+
void ActOnFinishCXXMemberSpecification(Scope *S, SourceLocation RLoc,
Decl *TagDecl, SourceLocation LBrac,
SourceLocation RBrac,
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index a2398fef623ea..2e230ce556459 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -86,6 +86,7 @@
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/SipHash.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TargetParser/Triple.h"
#include <algorithm>
@@ -3088,6 +3089,17 @@ QualType ASTContext::removeAddrSpaceQualType(QualType T) const {
return QualType(TypeNode, Quals.getFastQualifiers());
}
+uint16_t ASTContext::getPointerAuthVTablePointerDiscriminator(
+ const CXXRecordDecl *record) {
+ assert(record->isPolymorphic() &&
+ "Attempted to get vtable pointer discriminator on a monomorphic type");
+ std::unique_ptr<MangleContext> MC(createMangleContext());
+ SmallString<256> Str;
+ llvm::raw_svector_ostream Out(Str);
+ MC->mangleCXXVTable(record, Out);
+ return llvm::getPointerAuthStableSipHash16(Str.c_str());
+}
+
QualType ASTContext::getObjCGCQualType(QualType T,
Qualifiers::GC GCAttr) const {
QualType CanT = getCanonicalType(T);
@@ -13812,3 +13824,77 @@ StringRef ASTContext::getCUIDHash() const {
CUIDHash = llvm::utohexstr(llvm::MD5Hash(LangOpts.CUID), /*LowerCase=*/true);
return CUIDHash;
}
+
+const CXXRecordDecl *
+ASTContext::baseForVTableAuthentication(const CXXRecordDecl *thisClass) {
+ assert(thisClass);
+ assert(thisClass->isPolymorphic());
+ const CXXRecordDecl *primaryBase = thisClass;
+ while (1) {
+ assert(primaryBase);
+ assert(primaryBase->isPolymorphic());
+ auto &layout = getASTRecordLayout(primaryBase);
+ auto base = layout.getPrimaryBase();
+ if (!base || base == primaryBase || !base->isPolymorphic())
+ break;
+ primaryBase = base;
+ }
+ return primaryBase;
+}
+
+bool ASTContext::useAbbreviatedThunkName(GlobalDecl virtualMethodDecl,
+ StringRef mangledName) {
+ auto method = cast<CXXMethodDecl>(virtualMethodDe...
[truncated]
|
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