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[CodeGen] Ensure relative vtables use llvm.type.checked.load.relative #126785

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Merged
merged 2 commits into from
Feb 28, 2025
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[CodeGen] Ensure relative vtables use llvm.type.checked.load.relative #126785

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07c7c06
[CodeGen] Ensure relative vtables use llvm.type.checked.load.relative
PiJoules Feb 11, 2025
c88fdc1
Merge branch 'main' into relative-vtables-checked.load.relative
PiJoules Feb 28, 2025
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6 changes: 5 additions & 1 deletion clang/lib/CodeGen/CGClass.cpp
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Expand Up @@ -2937,9 +2937,13 @@ llvm::Value *CodeGenFunction::EmitVTableTypeCheckedLoad(
CGM.CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
llvm::Value *TypeId = llvm::MetadataAsValue::get(CGM.getLLVMContext(), MD);

auto CheckedLoadIntrinsic = CGM.getVTables().useRelativeLayout()
? llvm::Intrinsic::type_checked_load_relative
: llvm::Intrinsic::type_checked_load;
llvm::Value *CheckedLoad = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_checked_load),
CGM.getIntrinsic(CheckedLoadIntrinsic),
{VTable, llvm::ConstantInt::get(Int32Ty, VTableByteOffset), TypeId});

llvm::Value *CheckResult = Builder.CreateExtractValue(CheckedLoad, 1);

std::string TypeName = RD->getQualifiedNameAsString();
Expand Down
10 changes: 6 additions & 4 deletions clang/lib/CodeGen/CGVTables.h
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Expand Up @@ -75,10 +75,6 @@ class CodeGenVTables {
bool vtableHasLocalLinkage,
bool isCompleteDtor) const;

bool useRelativeLayout() const;

llvm::Type *getVTableComponentType() const;

public:
/// Add vtable components for the given vtable layout to the given
/// global initializer.
Expand Down Expand Up @@ -151,6 +147,12 @@ class CodeGenVTables {

/// Specify a global should not be instrumented with hwasan.
void RemoveHwasanMetadata(llvm::GlobalValue *GV) const;

/// Return the type used as components for a vtable.
llvm::Type *getVTableComponentType() const;

/// Return true if the relative vtable layout is used.
bool useRelativeLayout() const;
};

} // end namespace CodeGen
Expand Down
14 changes: 8 additions & 6 deletions clang/lib/CodeGen/ItaniumCXXABI.cpp
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Expand Up @@ -2189,20 +2189,22 @@ CGCallee ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
uint64_t VTableIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(GD);
llvm::Value *VFunc, *VTableSlotPtr = nullptr;
auto &Schema = CGM.getCodeGenOpts().PointerAuth.CXXVirtualFunctionPointers;

llvm::Type *ComponentTy = CGM.getVTables().getVTableComponentType();
uint64_t ByteOffset =
VTableIndex * CGM.getDataLayout().getTypeSizeInBits(ComponentTy) / 8;

if (!Schema && CGF.ShouldEmitVTableTypeCheckedLoad(MethodDecl->getParent())) {
VFunc = CGF.EmitVTableTypeCheckedLoad(
MethodDecl->getParent(), VTable, PtrTy,
VTableIndex *
CGM.getContext().getTargetInfo().getPointerWidth(LangAS::Default) /
8);
VFunc = CGF.EmitVTableTypeCheckedLoad(MethodDecl->getParent(), VTable,
PtrTy, ByteOffset);
} else {
CGF.EmitTypeMetadataCodeForVCall(MethodDecl->getParent(), VTable, Loc);

llvm::Value *VFuncLoad;
if (CGM.getItaniumVTableContext().isRelativeLayout()) {
VFuncLoad = CGF.Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::load_relative, {CGM.Int32Ty}),
{VTable, llvm::ConstantInt::get(CGM.Int32Ty, 4 * VTableIndex)});
{VTable, llvm::ConstantInt::get(CGM.Int32Ty, ByteOffset)});
} else {
VTableSlotPtr = CGF.Builder.CreateConstInBoundsGEP1_64(
PtrTy, VTable, VTableIndex, "vfn");
Expand Down
6 changes: 3 additions & 3 deletions clang/test/CodeGen/fat-lto-objects-cfi.cpp
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Expand Up @@ -70,9 +70,9 @@ void foo(const void* ptr, size_t len, long disp_addr,
// COM: llvm.type.checked.load, so we need to match the function body first.
// NO_CHECKED_LOAD-LABEL: entry:
// NO_CHECKED_LOAD-NEXT: %vtable = load ptr, ptr %p1
// NO_CHECKED_LOAD-NOT: llvm.type.checked.load
// NO_CHECKED_LOAD-NEXT: %vfunc = load ptr, ptr %vtable
// NO_CHECKED_LOAD-NEXT: %call = tail call {{.*}} %vfunc(ptr {{.*}} %p1)
// NO_CHECKED_LOAD-NOT: llvm.type.checked.load.relative
// NO_CHECKED_LOAD-NEXT: %rel_load = tail call ptr @llvm.load.relative.i32(ptr %vtable, i32 0)
// NO_CHECKED_LOAD-NEXT: %call = tail call {{.*}} %rel_load(ptr {{.*}} %p1)
// NO_CHECKED_LOAD-NEXT: ret void

// COM: Ensure that we don't crash in the backend anymore when clang uses
Expand Down
17 changes: 11 additions & 6 deletions clang/test/CodeGenCXX/type-metadata.cpp
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Expand Up @@ -30,7 +30,7 @@
// RUN: %clang_cc1 -fexperimental-relative-c++-abi-vtables -O2 -flto -flto-unit -triple x86_64-unknown-linux -fwhole-program-vtables -emit-llvm -o - %s | FileCheck --check-prefix=ITANIUM-OPT --check-prefix=RV-OPT-LAYOUT %s

// Tests for cfi + whole-program-vtables:
// RUN: %clang_cc1 -fexperimental-relative-c++-abi-vtables -flto -flto-unit -triple x86_64-unknown-linux -fvisibility=hidden -fsanitize=cfi-vcall -fsanitize-trap=cfi-vcall -fwhole-program-vtables -emit-llvm -o - %s | FileCheck --check-prefix=CFI --check-prefix=CFI-VT --check-prefix=ITANIUM-HIDDEN --check-prefix=ITANIUM-COMMON-MD --check-prefix=RV-MD --check-prefix=TC-ITANIUM %s
// RUN: %clang_cc1 -fexperimental-relative-c++-abi-vtables -flto -flto-unit -triple x86_64-unknown-linux -fvisibility=hidden -fsanitize=cfi-vcall -fsanitize-trap=cfi-vcall -fwhole-program-vtables -emit-llvm -o - %s | FileCheck --check-prefix=CFI --check-prefix=CFI-VT --check-prefix=ITANIUM-HIDDEN --check-prefix=ITANIUM-COMMON-MD --check-prefix=RV-MD --check-prefix=TC-ITANIUM-RV %s

// Tests that type metadata are annotated on vtables with `-profile-instrument=llvm` (which is equivalent to clang driver option `-fprofile-generate` without `-fcs-profile-generate`):
// - In clang driver, `-fprofile-instrument` cc1 option is set to 'llvm' iff clang driver option `-fprofile-generate{,=}` is taking effect.
Expand Down Expand Up @@ -178,7 +178,8 @@ void af(A *a) {
// TT-ITANIUM-HIDDEN: [[P:%[^ ]*]] = call i1 @llvm.type.test(ptr [[VT:%[^ ]*]], metadata !"_ZTS1A")
// TT-ITANIUM-DEFAULT: [[P:%[^ ]*]] = call i1 @llvm.public.type.test(ptr [[VT:%[^ ]*]], metadata !"_ZTS1A")
// TT-MS: [[P:%[^ ]*]] = call i1 @llvm.type.test(ptr [[VT:%[^ ]*]], metadata !"?AUA@@")
// TC-ITANIUM: [[PAIR:%[^ ]*]] = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata !"_ZTS1A")
// TC-ITANIUM: [[PAIR:%[^ ]*]] = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata !"_ZTS1A")
// TC-ITANIUM-RV: [[PAIR:%[^ ]*]] = call { ptr, i1 } @llvm.type.checked.load.relative(ptr {{%[^ ]*}}, i32 0, metadata !"_ZTS1A")
// TC-MS: [[PAIR:%[^ ]*]] = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata !"?AUA@@")
// CFI-VT: [[P:%[^ ]*]] = extractvalue { ptr, i1 } [[PAIR]], 1
// DIAG-NEXT: [[VTVALID0:%[^ ]*]] = call i1 @llvm.type.test(ptr [[VT]], metadata !"all-vtables")
Expand Down Expand Up @@ -211,7 +212,8 @@ void df1(D *d) {
// TT-ITANIUM-HIDDEN: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata ![[DTYPE:[0-9]+]])
// TT-ITANIUM-DEFAULT: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata ![[DTYPE:[0-9]+]])
// TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata !"?AUA@@")
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata ![[DTYPE:[0-9]+]])
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata ![[DTYPE:[0-9]+]])
// TC-ITANIUM-RV: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load.relative(ptr {{%[^ ]*}}, i32 0, metadata ![[DTYPE:[0-9]+]])
// TC-MS: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata !"?AUA@@")
d->f();
}
Expand All @@ -222,7 +224,8 @@ void dg1(D *d) {
// TT-ITANIUM-HIDDEN: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata !"_ZTS1B")
// TT-ITANIUM-DEFAULT: {{%[^ ]*}} = call i1 @llvm.public.type.test(ptr {{%[^ ]*}}, metadata !"_ZTS1B")
// TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata !"?AUB@@")
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 8, metadata !"_ZTS1B")
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 8, metadata !"_ZTS1B")
// TC-ITANIUM-RV: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load.relative(ptr {{%[^ ]*}}, i32 4, metadata !"_ZTS1B")
// TC-MS: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata !"?AUB@@")
d->g();
}
Expand All @@ -233,7 +236,8 @@ void dh1(D *d) {
// TT-ITANIUM-HIDDEN: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata ![[DTYPE]])
// TT-ITANIUM-DEFAULT: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata ![[DTYPE]])
// TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata ![[DTYPE:[0-9]+]])
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 16, metadata ![[DTYPE]])
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 16, metadata ![[DTYPE]])
// TC-ITANIUM-RV: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load.relative(ptr {{%[^ ]*}}, i32 8, metadata ![[DTYPE]])
// TC-MS: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 8, metadata ![[DTYPE:[0-9]+]])
d->h();
}
Expand Down Expand Up @@ -293,7 +297,8 @@ void f(D *d) {
// TT-ITANIUM-HIDDEN: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata !"_ZTSN5test21DE")
// TT-ITANIUM-DEFAULT: {{%[^ ]*}} = call i1 @llvm.public.type.test(ptr {{%[^ ]*}}, metadata !"_ZTSN5test21DE")
// TT-MS: {{%[^ ]*}} = call i1 @llvm.type.test(ptr {{%[^ ]*}}, metadata !"?AUA@test2@@")
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 8, metadata !"_ZTSN5test21DE")
// TC-ITANIUM: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 8, metadata !"_ZTSN5test21DE")
// TC-ITANIUM-RV: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load.relative(ptr {{%[^ ]*}}, i32 4, metadata !"_ZTSN5test21DE")
// TC-MS: {{%[^ ]*}} = call { ptr, i1 } @llvm.type.checked.load(ptr {{%[^ ]*}}, i32 0, metadata !"?AUA@test2@@")
d->m_fn1();
}
Expand Down
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