Prazek created this revision.
Prazek added reviewers: rsmith, majnemer, pcc.
Prazek added a subscriber: cfe-commits.
Adding !invariant.group to vptr load/stores for devirtualization purposes.
For more goto:
http://lists.llvm.org/pipermail/cfe-dev/2015-July/044227.htm
http://reviews.llvm.org/D12026
Files:
lib/CodeGen/CGAtomic.cpp
lib/CodeGen/CGClass.cpp
lib/CodeGen/CGExpr.cpp
lib/CodeGen/CGExprCXX.cpp
lib/CodeGen/CodeGenFunction.h
lib/CodeGen/CodeGenModule.cpp
lib/CodeGen/CodeGenModule.h
lib/CodeGen/ItaniumCXXABI.cpp
lib/CodeGen/MicrosoftCXXABI.cpp
test/CodeGenCXX/invariat.barrier-for-vptrs.cpp
Index: test/CodeGenCXX/invariat.barrier-for-vptrs.cpp
===================================================================
--- /dev/null
+++ test/CodeGenCXX/invariat.barrier-for-vptrs.cpp
@@ -0,0 +1,55 @@
+// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm %s -o - | FileCheck %s
+
+struct A {
+ virtual void foo();
+};
+
+// CHECK-LABEL: define void @_Z21testExternallyVisiblev()
+// CHECK: %vtable = load {{.*}} !invariant.group !1
+// CHECK-LABEL: }
+
+void testExternallyVisible() {
+ A *a = new A;
+ a->foo();
+}
+
+namespace {
+
+struct B {
+ virtual void bar();
+};
+
+struct C : B {
+ void bar();
+};
+
+}
+
+B *get(bool p) {
+ return p ? new B : new C;
+}
+
+// CHECK-LABEL: define void @_Z21testInternallyVisibleb(
+// CHECK: %vtable = load {{.*}}, !invariant.group !2
+
+void testInternallyVisible(bool p) {
+ B *b = get(p);
+ b->bar();
+}
+
+// Checking A::A()
+// CHECK-LABEL: define linkonce_odr void @_ZN1AC2Ev(%struct.A* %this)
+// CHECK: store {{.*}}, !invariant.group !1
+// CHECK-LABEL: }
+
+// Checking C::C()
+// CHECK-LABEL: define internal void @_ZN12_GLOBAL__N_11BC2Ev(%"struct.(anonymous namespace)::B"*
+// CHECK: store {{.*}}, !invariant.group !2
+
+// Checking B::B()
+// CHECK-LABEL: define internal void @_ZN12_GLOBAL__N_11CC2Ev(%"struct.(anonymous namespace)::C"*
+// CHECK: store {{.*}}, !invariant.group !3
+
+// CHECK: !1 = !{!"_ZTS1A.vptr.invariant.group"}
+// CHECK: !2 = distinct !{}
+// CHECK: !3 = distinct !{}
Index: lib/CodeGen/MicrosoftCXXABI.cpp
===================================================================
--- lib/CodeGen/MicrosoftCXXABI.cpp
+++ lib/CodeGen/MicrosoftCXXABI.cpp
@@ -1800,7 +1800,9 @@
Ty = Ty->getPointerTo()->getPointerTo();
llvm::Value *VPtr =
adjustThisArgumentForVirtualFunctionCall(CGF, GD, This, true);
- llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty);
+
+ auto *MethodDecl = cast<CXXMethodDecl>(GD.getDecl());
+ llvm::Value *VTable = CGF.GetVTablePtr(VPtr, Ty, MethodDecl->getParent());
MicrosoftVTableContext::MethodVFTableLocation ML =
CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
@@ -1927,7 +1929,8 @@
// Load the vfptr and then callee from the vftable. The callee should have
// adjusted 'this' so that the vfptr is at offset zero.
llvm::Value *VTable = CGF.GetVTablePtr(
- getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo());
+ getThisValue(CGF), ThunkTy->getPointerTo()->getPointerTo(),
+ MD->getParent());
llvm::Value *VFuncPtr =
CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
llvm::Value *Callee = CGF.Builder.CreateLoad(VFuncPtr);
Index: lib/CodeGen/ItaniumCXXABI.cpp
===================================================================
--- lib/CodeGen/ItaniumCXXABI.cpp
+++ lib/CodeGen/ItaniumCXXABI.cpp
@@ -493,7 +493,7 @@
// Cast the adjusted this to a pointer to vtable pointer and load.
llvm::Type *VTableTy = Builder.getInt8PtrTy();
- llvm::Value *VTable = CGF.GetVTablePtr(This, VTableTy);
+ llvm::Value *VTable = CGF.GetVTablePtr(This, VTableTy, RD);
// Apply the offset.
llvm::Value *VTableOffset = FnAsInt;
@@ -919,7 +919,10 @@
// to pass to the deallocation function.
// Grab the vtable pointer as an intptr_t*.
- llvm::Value *VTable = CGF.GetVTablePtr(Ptr, CGF.IntPtrTy->getPointerTo());
+ auto *ClassDecl =
+ cast<CXXRecordDecl>(ElementType->getAs<RecordType>()->getDecl());
+ llvm::Value *VTable =
+ CGF.GetVTablePtr(Ptr, CGF.IntPtrTy->getPointerTo(), ClassDecl);
// Track back to entry -2 and pull out the offset there.
llvm::Value *OffsetPtr = CGF.Builder.CreateConstInBoundsGEP1_64(
@@ -1116,8 +1119,10 @@
QualType SrcRecordTy,
llvm::Value *ThisPtr,
llvm::Type *StdTypeInfoPtrTy) {
+ auto *ClassDecl =
+ cast<CXXRecordDecl>(SrcRecordTy->getAs<RecordType>()->getDecl());
llvm::Value *Value =
- CGF.GetVTablePtr(ThisPtr, StdTypeInfoPtrTy->getPointerTo());
+ CGF.GetVTablePtr(ThisPtr, StdTypeInfoPtrTy->getPointerTo(), ClassDecl);
// Load the type info.
Value = CGF.Builder.CreateConstInBoundsGEP1_64(Value, -1ULL);
@@ -1179,8 +1184,11 @@
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Type *DestLTy = CGF.ConvertType(DestTy);
+ auto *ClassDecl =
+ cast<CXXRecordDecl>(SrcRecordTy->getAs<RecordType>()->getDecl());
// Get the vtable pointer.
- llvm::Value *VTable = CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo());
+ llvm::Value *VTable =
+ CGF.GetVTablePtr(Value, PtrDiffLTy->getPointerTo(), ClassDecl);
// Get the offset-to-top from the vtable.
llvm::Value *OffsetToTop =
@@ -1206,7 +1214,7 @@
llvm::Value *This,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
- llvm::Value *VTablePtr = CGF.GetVTablePtr(This, CGM.Int8PtrTy);
+ llvm::Value *VTablePtr = CGF.GetVTablePtr(This, CGM.Int8PtrTy, ClassDecl);
CharUnits VBaseOffsetOffset =
CGM.getItaniumVTableContext().getVirtualBaseOffsetOffset(ClassDecl,
BaseClassDecl);
@@ -1492,10 +1500,11 @@
SourceLocation Loc) {
GD = GD.getCanonicalDecl();
Ty = Ty->getPointerTo()->getPointerTo();
- llvm::Value *VTable = CGF.GetVTablePtr(This, Ty);
+ auto *MethodDecl = cast<CXXMethodDecl>(GD.getDecl());
+ llvm::Value *VTable = CGF.GetVTablePtr(This, Ty, MethodDecl->getParent());
if (CGF.SanOpts.has(SanitizerKind::CFIVCall))
- CGF.EmitVTablePtrCheckForCall(cast<CXXMethodDecl>(GD.getDecl()), VTable,
+ CGF.EmitVTablePtrCheckForCall(MethodDecl, VTable,
CodeGenFunction::CFITCK_VCall, Loc);
uint64_t VTableIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(GD);
Index: lib/CodeGen/CodeGenModule.h
===================================================================
--- lib/CodeGen/CodeGenModule.h
+++ lib/CodeGen/CodeGenModule.h
@@ -490,6 +490,27 @@
llvm::DenseMap<const Decl *, bool> DeferredEmptyCoverageMappingDecls;
std::unique_ptr<CoverageMappingModuleGen> CoverageMapping;
+
+ /// Helper class for generating invariant.group metadata.
+ /// For externally visible classes it generates node like this
+ /// !{ "%mangledName%.%TAG%.invariant.group" }
+ /// and for internally visible classes it generates empty distinct nodes.
+ class InvariantGroupMetadataFactory {
+ CodeGenModule &CGM;
+ const std::string tag;
+ llvm::SmallDenseMap<const CXXRecordDecl *, llvm::MDNode *> distinctMDNodes;
+
+ std::string getFullName(const CXXRecordDecl *ClassDecl) const;
+ llvm::MDNode *getInternallyVisibleMD(const CXXRecordDecl *ClassDecl);
+ llvm::MDNode *getExternallyVisibleMD(const CXXRecordDecl *ClassDecl) const;
+
+ public:
+ InvariantGroupMetadataFactory(CodeGenModule &CGM, std::string tag);
+ llvm::MDNode *getInvariantMetadata(const CXXRecordDecl *ClassDecl);
+ };
+
+ InvariantGroupMetadataFactory vptrInvariantGroupMetadataFactory;
+
public:
CodeGenModule(ASTContext &C, const HeaderSearchOptions &headersearchopts,
const PreprocessorOptions &ppopts,
@@ -659,9 +680,13 @@
/// is the same as the type. For struct-path aware TBAA, the tag
/// is different from the type: base type, access type and offset.
/// When ConvertTypeToTag is true, we create a tag based on the scalar type.
- void DecorateInstruction(llvm::Instruction *Inst,
- llvm::MDNode *TBAAInfo,
- bool ConvertTypeToTag = true);
+ void DecorateInstructionWithTBAA(llvm::Instruction *Inst,
+ llvm::MDNode *TBAAInfo,
+ bool ConvertTypeToTag = true);
+
+ /// Adds !invariant.barrier !tag to instruction
+ void DecorateInstructionWithInvariantGroup(llvm::Instruction *I,
+ const CXXRecordDecl *RD);
/// Emit the given number of characters as a value of type size_t.
llvm::ConstantInt *getSize(CharUnits numChars);
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -92,7 +92,8 @@
NSConcreteStackBlock(nullptr), BlockObjectAssign(nullptr),
BlockObjectDispose(nullptr), BlockDescriptorType(nullptr),
GenericBlockLiteralType(nullptr), LifetimeStartFn(nullptr),
- LifetimeEndFn(nullptr), SanitizerMD(new SanitizerMetadata(*this)) {
+ LifetimeEndFn(nullptr), SanitizerMD(new SanitizerMetadata(*this)),
+ vptrInvariantGroupMetadataFactory(*this, "vptr") {
// Initialize the type cache.
llvm::LLVMContext &LLVMContext = M.getContext();
@@ -472,16 +473,23 @@
/// and struct-path aware TBAA, the tag has the same format:
/// base type, access type and offset.
/// When ConvertTypeToTag is true, we create a tag based on the scalar type.
-void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst,
- llvm::MDNode *TBAAInfo,
- bool ConvertTypeToTag) {
+void CodeGenModule::DecorateInstructionWithTBAA(llvm::Instruction *Inst,
+ llvm::MDNode *TBAAInfo,
+ bool ConvertTypeToTag) {
if (ConvertTypeToTag && TBAA)
Inst->setMetadata(llvm::LLVMContext::MD_tbaa,
TBAA->getTBAAScalarTagInfo(TBAAInfo));
else
Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo);
}
+void CodeGenModule::DecorateInstructionWithInvariantGroup(
+ llvm::Instruction *I, const CXXRecordDecl *RD) {
+ auto *MetaData =
+ vptrInvariantGroupMetadataFactory.getInvariantMetadata(RD);
+ I->setMetadata("invariant.group", MetaData);
+}
+
void CodeGenModule::Error(SourceLocation loc, StringRef message) {
unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, "%0");
getDiags().Report(Context.getFullLoc(loc), diagID) << message;
@@ -1486,6 +1494,47 @@
return !isTriviallyRecursive(F);
}
+CodeGenModule::InvariantGroupMetadataFactory::InvariantGroupMetadataFactory(
+ CodeGenModule &CGM_, std::string tag_)
+ : CGM(CGM_), tag(std::move(tag_)) {}
+
+std::string CodeGenModule::InvariantGroupMetadataFactory::getFullName(
+ const CXXRecordDecl *ClassDecl) const {
+ std::string MangledName;
+ llvm::raw_string_ostream MangledNameStream(MangledName);
+ CGM.getCXXABI().getMangleContext().mangleTypeName(
+ QualType(ClassDecl->getTypeForDecl(), 0), MangledNameStream);
+
+ MangledNameStream << "." << tag << ".invariant.group";
+ MangledNameStream.flush();
+ return MangledName;
+}
+
+llvm::MDNode *
+CodeGenModule::InvariantGroupMetadataFactory::getInternallyVisibleMD(
+ const CXXRecordDecl *ClassDecl) {
+ assert(ClassDecl != nullptr);
+ llvm::MDNode *&MetaData = distinctMDNodes[ClassDecl];
+ if (!MetaData)
+ MetaData = llvm::MDNode::getDistinct(CGM.getLLVMContext(), {});
+ return MetaData;
+}
+
+llvm::MDNode *
+CodeGenModule::InvariantGroupMetadataFactory::getExternallyVisibleMD(
+ const CXXRecordDecl *ClassDecl) const {
+ auto *MDString = llvm::MDString::get(CGM.getLLVMContext(), getFullName(ClassDecl));
+ return llvm::MDNode::get(CGM.getLLVMContext(), MDString);
+}
+
+llvm::MDNode *
+CodeGenModule::InvariantGroupMetadataFactory::getInvariantMetadata(
+ const CXXRecordDecl *ClassDecl) {
+ if (ClassDecl->isExternallyVisible())
+ return getExternallyVisibleMD(ClassDecl);
+ return getInternallyVisibleMD(ClassDecl);
+}
+
/// If the type for the method's class was generated by
/// CGDebugInfo::createContextChain(), the cache contains only a
/// limited DIType without any declarations. Since EmitFunctionStart()
Index: lib/CodeGen/CodeGenFunction.h
===================================================================
--- lib/CodeGen/CodeGenFunction.h
+++ lib/CodeGen/CodeGenFunction.h
@@ -1335,7 +1335,8 @@
/// GetVTablePtr - Return the Value of the vtable pointer member pointed
/// to by This.
- llvm::Value *GetVTablePtr(llvm::Value *This, llvm::Type *Ty);
+ llvm::Value *GetVTablePtr(llvm::Value *This, llvm::Type *VTableTy,
+ const CXXRecordDecl *RD);
enum CFITypeCheckKind {
CFITCK_VCall,
Index: lib/CodeGen/CGExprCXX.cpp
===================================================================
--- lib/CodeGen/CGExprCXX.cpp
+++ lib/CodeGen/CGExprCXX.cpp
@@ -259,7 +259,7 @@
} else {
if (SanOpts.has(SanitizerKind::CFINVCall) &&
MD->getParent()->isDynamicClass()) {
- llvm::Value *VTable = GetVTablePtr(This, Int8PtrTy);
+ llvm::Value *VTable = GetVTablePtr(This, Int8PtrTy, MD->getParent());
EmitVTablePtrCheckForCall(MD, VTable, CFITCK_NVCall, CE->getLocStart());
}
Index: lib/CodeGen/CGExpr.cpp
===================================================================
--- lib/CodeGen/CGExpr.cpp
+++ lib/CodeGen/CGExpr.cpp
@@ -1172,7 +1172,8 @@
llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
TBAAOffset);
if (TBAAPath)
- CGM.DecorateInstruction(Load, TBAAPath, false/*ConvertTypeToTag*/);
+ CGM.DecorateInstructionWithTBAA(Load, TBAAPath,
+ false /*ConvertTypeToTag*/);
}
bool NeedsBoolCheck =
@@ -1284,7 +1285,8 @@
llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
TBAAOffset);
if (TBAAPath)
- CGM.DecorateInstruction(Store, TBAAPath, false/*ConvertTypeToTag*/);
+ CGM.DecorateInstructionWithTBAA(Store, TBAAPath,
+ false /*ConvertTypeToTag*/);
}
}
@@ -2716,7 +2718,7 @@
else
tbaa = CGM.getTBAAInfo(type);
if (tbaa)
- CGM.DecorateInstruction(load, tbaa);
+ CGM.DecorateInstructionWithTBAA(load, tbaa);
}
addr = load;
Index: lib/CodeGen/CGClass.cpp
===================================================================
--- lib/CodeGen/CGClass.cpp
+++ lib/CodeGen/CGClass.cpp
@@ -25,6 +25,7 @@
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Metadata.h"
using namespace clang;
using namespace CodeGen;
@@ -1850,7 +1851,8 @@
This =
ApplyNonVirtualAndVirtualOffset(*this, This, NonVirtualOffset, nullptr);
- llvm::Value *VPtrValue = GetVTablePtr(This, VTableGlobal->getType());
+ llvm::Value *VPtrValue =
+ GetVTablePtr(This, VTableGlobal->getType(), Vptr.VTableClass);
llvm::Value *Cmp =
Builder.CreateICmpEQ(VPtrValue, VTableGlobal, "cmp.vtables");
Builder.CreateAssumption(Cmp);
@@ -2072,7 +2074,8 @@
VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy);
llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
- CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr());
+ CGM.DecorateInstructionWithTBAA(Store, CGM.getTBAAInfoForVTablePtr());
+ CGM.DecorateInstructionWithInvariantGroup(Store, Vptr.VTableClass);
}
CodeGenFunction::VPtrsVector
@@ -2162,10 +2165,14 @@
}
llvm::Value *CodeGenFunction::GetVTablePtr(llvm::Value *This,
- llvm::Type *Ty) {
- llvm::Value *VTablePtrSrc = Builder.CreateBitCast(This, Ty->getPointerTo());
+ llvm::Type *VTableTy,
+ const CXXRecordDecl *RD) {
+ llvm::Value *VTablePtrSrc =
+ Builder.CreateBitCast(This, VTableTy->getPointerTo());
llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
- CGM.DecorateInstruction(VTable, CGM.getTBAAInfoForVTablePtr());
+ CGM.DecorateInstructionWithTBAA(VTable, CGM.getTBAAInfoForVTablePtr());
+ CGM.DecorateInstructionWithInvariantGroup(VTable, RD);
+
return VTable;
}
@@ -2249,7 +2256,7 @@
EmitBlock(CheckBlock);
}
- llvm::Value *VTable = GetVTablePtr(Derived, Int8PtrTy);
+ llvm::Value *VTable = GetVTablePtr(Derived, Int8PtrTy, ClassDecl);
EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc);
if (MayBeNull) {
Index: lib/CodeGen/CGAtomic.cpp
===================================================================
--- lib/CodeGen/CGAtomic.cpp
+++ lib/CodeGen/CGAtomic.cpp
@@ -1251,7 +1251,7 @@
if (IsVolatile)
Load->setVolatile(true);
if (LVal.getTBAAInfo())
- CGF.CGM.DecorateInstruction(Load, LVal.getTBAAInfo());
+ CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo());
return Load;
}
@@ -1780,7 +1780,7 @@
if (IsVolatile)
store->setVolatile(true);
if (dest.getTBAAInfo())
- CGM.DecorateInstruction(store, dest.getTBAAInfo());
+ CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo());
return;
}
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