llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Daniil Kovalev (kovdan01) <details> <summary>Changes</summary> In #<!-- -->99726, `-fptrauth-type-info-vtable-pointer-discrimination` was introduced, which is intended to enable type and address discrimination for type_info vtable pointers. However, some codegen logic for actually enabling address discrimination was missing. This patch addresses the issue. Fixes #<!-- -->101716 --- Full diff: https://github.com/llvm/llvm-project/pull/102199.diff 4 Files Affected: - (modified) clang/lib/CodeGen/ItaniumCXXABI.cpp (+17-3) - (modified) clang/test/CodeGenCXX/ptrauth-type-info-vtable.cpp (+1-1) - (modified) llvm/include/llvm/IR/Constants.h (+12-6) - (added) llvm/test/CodeGen/AArch64/ptrauth-type-info-vptr-discr.ll (+20) ``````````diff diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp index 9b5227772125b..13aeb3e75d684 100644 --- a/clang/lib/CodeGen/ItaniumCXXABI.cpp +++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp @@ -3955,9 +3955,23 @@ void ItaniumRTTIBuilder::BuildVTablePointer(const Type *Ty) { VTable, Two); } - if (auto &Schema = CGM.getCodeGenOpts().PointerAuth.CXXTypeInfoVTablePointer) - VTable = CGM.getConstantSignedPointer(VTable, Schema, nullptr, GlobalDecl(), - QualType(Ty, 0)); + if (const auto &Schema = + CGM.getCodeGenOpts().PointerAuth.CXXTypeInfoVTablePointer) { + llvm::PointerType *PtrTy = llvm::PointerType::get( + CGM.getLLVMContext(), + CGM.getModule().getDataLayout().getProgramAddressSpace()); + llvm::Constant *StorageAddress = + (Schema.isAddressDiscriminated() + ? llvm::ConstantExpr::getIntToPtr( + llvm::ConstantInt::get( + CGM.IntPtrTy, + llvm::ConstantPtrAuth:: + AddrDiscriminator_CXXTypeInfoVTablePointer), + PtrTy) + : nullptr); + VTable = CGM.getConstantSignedPointer(VTable, Schema, StorageAddress, + GlobalDecl(), QualType(Ty, 0)); + } Fields.push_back(VTable); } diff --git a/clang/test/CodeGenCXX/ptrauth-type-info-vtable.cpp b/clang/test/CodeGenCXX/ptrauth-type-info-vtable.cpp index 174aeda89d175..61eef73b5be2a 100644 --- a/clang/test/CodeGenCXX/ptrauth-type-info-vtable.cpp +++ b/clang/test/CodeGenCXX/ptrauth-type-info-vtable.cpp @@ -65,7 +65,7 @@ extern "C" int disc_std_type_info = __builtin_ptrauth_string_discriminator("_ZTV // NODISC: @_ZTI10TestStruct = constant { ptr, ptr } { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), i32 2), ptr @_ZTS10TestStruct }, align 8 -// DISC: @_ZTI10TestStruct = constant { ptr, ptr } { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), i32 2, i64 [[STDTYPEINFO_DISC]]), ptr @_ZTS10TestStruct }, align 8 +// DISC: @_ZTI10TestStruct = constant { ptr, ptr } { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), i32 2, i64 [[STDTYPEINFO_DISC]], ptr inttoptr (i64 1 to ptr)), ptr @_ZTS10TestStruct }, align 8 struct TestStruct { virtual ~TestStruct(); diff --git a/llvm/include/llvm/IR/Constants.h b/llvm/include/llvm/IR/Constants.h index 2788751e8b62a..aaa1c197651a6 100644 --- a/llvm/include/llvm/IR/Constants.h +++ b/llvm/include/llvm/IR/Constants.h @@ -1056,12 +1056,18 @@ class ConstantPtrAuth final : public Constant { return !getAddrDiscriminator()->isNullValue(); } - /// A constant value for the address discriminator which has special - /// significance to ctors/dtors lowering. Regular address discrimination can't - /// be applied for them since uses of llvm.global_{c|d}tors are disallowed - /// (see Verifier::visitGlobalVariable) and we can't emit getelementptr - /// expressions referencing these special arrays. - enum { AddrDiscriminator_CtorsDtors = 1 }; + /// Constant values for the address discriminator which have special + /// significance to lowering in some contexts. + /// - For ctors/dtors, regular address discrimination can't + /// be applied for them since uses of llvm.global_{c|d}tors are disallowed + /// (see Verifier::visitGlobalVariable) and we can't emit getelementptr + /// expressions referencing these special arrays. + /// - For vtable pointers of std::type_info and classes derived from it, + /// we do not know the storage address when emitting ptrauth constant. + enum { + AddrDiscriminator_CtorsDtors = 1, + AddrDiscriminator_CXXTypeInfoVTablePointer = 1 + }; /// Whether the address uses a special address discriminator. /// These discriminators can't be used in real pointer-auth values; they diff --git a/llvm/test/CodeGen/AArch64/ptrauth-type-info-vptr-discr.ll b/llvm/test/CodeGen/AArch64/ptrauth-type-info-vptr-discr.ll new file mode 100644 index 0000000000000..b25a32f856b7a --- /dev/null +++ b/llvm/test/CodeGen/AArch64/ptrauth-type-info-vptr-discr.ll @@ -0,0 +1,20 @@ +; RUN: llc -mtriple aarch64-linux-gnu -mattr=+pauth -filetype=asm -o - %s | FileCheck --check-prefix=ELF %s +; RUN: llc -mtriple aarch64-apple-darwin -mattr=+pauth -filetype=asm -o - %s | FileCheck --check-prefix=MACHO %s + +; ELF-LABEL: _ZTI10Disc: +; ELF-NEXT: .xword (_ZTVN10__cxxabiv117__class_type_infoE+16)@AUTH(da,45546,addr) +; ELF-LABEL: _ZTI10NoDisc: +; ELF-NEXT: .xword (_ZTVN10__cxxabiv117__class_type_infoE+16)@AUTH(da,45546) + +; MACHO-LABEL: __ZTI10Disc: +; MACHO-NEXT: .quad (__ZTVN10__cxxabiv117__class_type_infoE+16)@AUTH(da,45546,addr) +; MACHO-LABEL: __ZTI10NoDisc: +; MACHO-NEXT: .quad (__ZTVN10__cxxabiv117__class_type_infoE+16)@AUTH(da,45546) + +@_ZTVN10__cxxabiv117__class_type_infoE = external global [0 x ptr] + +@_ZTS10Disc = constant [4 x i8] c"Disc", align 1 +@_ZTI10Disc = constant { ptr, ptr } { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), i32 2, i64 45546, ptr inttoptr (i64 1 to ptr)), ptr @_ZTS10Disc }, align 8 + +@_ZTS10NoDisc = constant [6 x i8] c"NoDisc", align 1 +@_ZTI10NoDisc = constant { ptr, ptr } { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @_ZTVN10__cxxabiv117__class_type_infoE, i64 2), i32 2, i64 45546), ptr @_ZTS10NoDisc }, align 8 `````````` </details> https://github.com/llvm/llvm-project/pull/102199 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
