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Decorating vptr load & stores with !invariant.group

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Adding !invariant.group to vptr load/stores for devirtualization purposes.
For more goto:
http://lists.llvm.org/pipermail/cfe-dev/2015-July/044227.html

http://reviews.llvm.org/D12026

llvm-svn: 247725
This commit is contained in:
Piotr Padlewski 2015-09-15 21:46:55 +00:00
parent 9d0ecf27a7
commit 4b1ac72cd4
10 changed files with 144 additions and 28 deletions
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4
clang/lib/CodeGen/CGAtomic.cpp
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@ -1246,7 +1246,7 @@ llvm::Value *AtomicInfo::EmitAtomicLoadOp(llvm::AtomicOrdering AO,
if (IsVolatile)
Load->setVolatile(true);
if (LVal.getTBAAInfo())
CGF.CGM.DecorateInstruction(Load, LVal.getTBAAInfo());
CGF.CGM.DecorateInstructionWithTBAA(Load, LVal.getTBAAInfo());
return Load;
}
@ -1769,7 +1769,7 @@ void CodeGenFunction::EmitAtomicStore(RValue rvalue, LValue dest,
if (IsVolatile)
store->setVolatile(true);
if (dest.getTBAAInfo())
CGM.DecorateInstruction(store, dest.getTBAAInfo());
CGM.DecorateInstructionWithTBAA(store, dest.getTBAAInfo());
return;
}

24
clang/lib/CodeGen/CGClass.cpp
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@ -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;
@ -2087,7 +2088,8 @@ void CodeGenFunction::EmitVTableAssumptionLoad(const VPtr &Vptr, Address This) {
ApplyNonVirtualAndVirtualOffset(*this, This, NonVirtualOffset, nullptr,
Vptr.VTableClass, Vptr.NearestVBase);
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);
@ -2306,7 +2308,10 @@ void CodeGenFunction::InitializeVTablePointer(const VPtr &Vptr) {
VTableAddressPoint = Builder.CreateBitCast(VTableAddressPoint, VTablePtrTy);
llvm::StoreInst *Store = Builder.CreateStore(VTableAddressPoint, VTableField);
CGM.DecorateInstruction(Store, CGM.getTBAAInfoForVTablePtr());
CGM.DecorateInstructionWithTBAA(Store, CGM.getTBAAInfoForVTablePtr());
if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
CGM.getCodeGenOpts().StrictVTablePointers)
CGM.DecorateInstructionWithInvariantGroup(Store, Vptr.VTableClass);
}
CodeGenFunction::VPtrsVector
@ -2393,10 +2398,16 @@ void CodeGenFunction::InitializeVTablePointers(const CXXRecordDecl *RD) {
}
llvm::Value *CodeGenFunction::GetVTablePtr(Address This,
llvm::Type *Ty) {
Address VTablePtrSrc = Builder.CreateElementBitCast(This, Ty);
llvm::Type *VTableTy,
const CXXRecordDecl *RD) {
Address VTablePtrSrc = Builder.CreateElementBitCast(This, VTableTy);
llvm::Instruction *VTable = Builder.CreateLoad(VTablePtrSrc, "vtable");
CGM.DecorateInstruction(VTable, CGM.getTBAAInfoForVTablePtr());
CGM.DecorateInstructionWithTBAA(VTable, CGM.getTBAAInfoForVTablePtr());
if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
CGM.getCodeGenOpts().StrictVTablePointers)
CGM.DecorateInstructionWithInvariantGroup(VTable, RD);
return VTable;
}
@ -2481,7 +2492,8 @@ void CodeGenFunction::EmitVTablePtrCheckForCast(QualType T,
}
llvm::Value *VTable =
GetVTablePtr(Address(Derived, getPointerAlign()), Int8PtrTy);
GetVTablePtr(Address(Derived, getPointerAlign()), Int8PtrTy, ClassDecl);
EmitVTablePtrCheck(ClassDecl, VTable, TCK, Loc);
if (MayBeNull) {

8
clang/lib/CodeGen/CGExpr.cpp
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@ -1277,7 +1277,8 @@ llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
TBAAOffset);
if (TBAAPath)
CGM.DecorateInstruction(Load, TBAAPath, false/*ConvertTypeToTag*/);
CGM.DecorateInstructionWithTBAA(Load, TBAAPath,
false /*ConvertTypeToTag*/);
}
bool NeedsBoolCheck =
@ -1391,7 +1392,8 @@ void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, Address Addr,
llvm::MDNode *TBAAPath = CGM.getTBAAStructTagInfo(TBAABaseType, TBAAInfo,
TBAAOffset);
if (TBAAPath)
CGM.DecorateInstruction(Store, TBAAPath, false/*ConvertTypeToTag*/);
CGM.DecorateInstructionWithTBAA(Store, TBAAPath,
false /*ConvertTypeToTag*/);
}
}
@ -3115,7 +3117,7 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
else
tbaa = CGM.getTBAAInfo(type);
if (tbaa)
CGM.DecorateInstruction(load, tbaa);
CGM.DecorateInstructionWithTBAA(load, tbaa);
}
mayAlias = false;

2
clang/lib/CodeGen/CGExprCXX.cpp
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@ -258,7 +258,7 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
} 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());
}

3
clang/lib/CodeGen/CodeGenFunction.h
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@ -1380,7 +1380,8 @@ public:
/// GetVTablePtr - Return the Value of the vtable pointer member pointed
/// to by This.
llvm::Value *GetVTablePtr(Address This, llvm::Type *Ty);
llvm::Value *GetVTablePtr(Address This, llvm::Type *VTableTy,
const CXXRecordDecl *VTableClass);
enum CFITypeCheckKind {
CFITCK_VCall,

16
clang/lib/CodeGen/CodeGenModule.cpp
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@ -507,9 +507,9 @@ llvm::MDNode *CodeGenModule::getTBAAStructTagInfo(QualType BaseTy,
/// 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));
@ -517,6 +517,16 @@ void CodeGenModule::DecorateInstruction(llvm::Instruction *Inst,
Inst->setMetadata(llvm::LLVMContext::MD_tbaa, TBAAInfo);
}
void CodeGenModule::DecorateInstructionWithInvariantGroup(
llvm::Instruction *I, const CXXRecordDecl *RD) {
llvm::Metadata *MD = CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
auto *MetaDataNode = dyn_cast<llvm::MDNode>(MD);
// Check if we have to wrap MDString in MDNode.
if (!MetaDataNode)
MetaDataNode = llvm::MDNode::get(getLLVMContext(), MD);
I->setMetadata("invariant.group", MetaDataNode);
}
void CodeGenModule::Error(SourceLocation loc, StringRef message) {
unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, "%0");
getDiags().Report(Context.getFullLoc(loc), diagID) << message;

10
clang/lib/CodeGen/CodeGenModule.h
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@ -658,9 +658,13 @@ public:
/// 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);

23
clang/lib/CodeGen/ItaniumCXXABI.cpp
View File

@ -584,7 +584,7 @@ llvm::Value *ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
CGF.CGM.getDynamicOffsetAlignment(ThisAddr.getAlignment(), RD,
CGF.getPointerAlign());
llvm::Value *VTable =
CGF.GetVTablePtr(Address(This, VTablePtrAlign), VTableTy);
CGF.GetVTablePtr(Address(This, VTablePtrAlign), VTableTy, RD);
// Apply the offset.
llvm::Value *VTableOffset = FnAsInt;
@ -1012,7 +1012,10 @@ void ItaniumCXXABI::emitVirtualObjectDelete(CodeGenFunction &CGF,
// 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(
@ -1211,8 +1214,10 @@ llvm::Value *ItaniumCXXABI::EmitTypeid(CodeGenFunction &CGF,
QualType SrcRecordTy,
Address 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);
@ -1275,8 +1280,11 @@ llvm::Value *ItaniumCXXABI::EmitDynamicCastToVoid(CodeGenFunction &CGF,
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(ThisAddr, PtrDiffLTy->getPointerTo());
llvm::Value *VTable = CGF.GetVTablePtr(ThisAddr, PtrDiffLTy->getPointerTo(),
ClassDecl);
// Get the offset-to-top from the vtable.
llvm::Value *OffsetToTop =
@ -1305,7 +1313,7 @@ ItaniumCXXABI::GetVirtualBaseClassOffset(CodeGenFunction &CGF,
Address 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);
@ -1591,10 +1599,11 @@ llvm::Value *ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
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);

7
clang/lib/CodeGen/MicrosoftCXXABI.cpp
View File

@ -1831,7 +1831,9 @@ llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
Ty = Ty->getPointerTo()->getPointerTo();
Address 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);
@ -1958,7 +1960,8 @@ llvm::Function *MicrosoftCXXABI::EmitVirtualMemPtrThunk(
// 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(
getThisAddress(CGF), ThunkTy->getPointerTo()->getPointerTo());
getThisAddress(CGF), ThunkTy->getPointerTo()->getPointerTo(), MD->getParent());
llvm::Value *VFuncPtr =
CGF.Builder.CreateConstInBoundsGEP1_64(VTable, ML.Index, "vfn");
llvm::Value *Callee =

75
clang/test/CodeGenCXX/invariant.group-for-vptrs.cpp Normal file
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@ -0,0 +1,75 @@
// RUN: %clang_cc1 -triple %itanium_abi_triple -emit-llvm %s -fstrict-vtable-pointers -O1 -o - -disable-llvm-optzns | FileCheck %s
struct A {
virtual void foo();
};
struct D : A {
void foo();
};
// CHECK-LABEL: define void @_Z21testExternallyVisiblev()
void testExternallyVisible() {
A *a = new A;
// CHECK: load {{.*}} !invariant.group ![[A_MD:[0-9]+]]
a->foo();
D *d = new D;
// CHECK: call void @_ZN1DC1Ev(
// CHECK: load {{.*}} !invariant.group ![[D_MD:[0-9]+]]
d->foo();
A *a2 = d;
// CHECK: load {{.*}} !invariant.group ![[A_MD]]
a2->foo();
}
// CHECK-LABEL: }
namespace {
struct B {
virtual void bar();
};
struct C : B {
void bar();
};
}
// CHECK-LABEL: define void @_Z21testInternallyVisibleb(
void testInternallyVisible(bool p) {
B *b = new B;
// CHECK: = load {{.*}}, !invariant.group ![[B_MD:[0-9]+]]
b->bar();
// CHECK: call void @_ZN12_GLOBAL__N_11CC1Ev(
C *c = new C;
// CHECK: = load {{.*}}, !invariant.group ![[C_MD:[0-9]+]]
c->bar();
}
// Checking A::A()
// CHECK-LABEL: define linkonce_odr void @_ZN1AC2Ev(
// CHECK: store {{.*}}, !invariant.group ![[A_MD]]
// CHECK-LABEL: }
// Checking D::D()
// CHECK-LABEL: define linkonce_odr void @_ZN1DC2Ev(
// CHECK: call void @_ZN1AC2Ev(%struct.A*
// CHECK: = call i8* @llvm.invariant.group.barrier(i8*
// CHECK: store {{.*}} !invariant.group ![[D_MD]]
// Checking B::B()
// CHECK-LABEL: define internal void @_ZN12_GLOBAL__N_11BC2Ev(
// CHECK: store {{.*}}, !invariant.group ![[B_MD]]
// Checking C::C()
// CHECK-LABEL: define internal void @_ZN12_GLOBAL__N_11CC2Ev(
// CHECK: store {{.*}}, !invariant.group ![[C_MD]]
// CHECK: ![[A_MD]] = !{!"_ZTS1A"}
// CHECK: ![[D_MD]] = !{!"_ZTS1D"}
// CHECK: ![[B_MD]] = distinct !{}
// CHECK: ![[C_MD]] = distinct !{}