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-rw-r--r--lib/CodeGen/CGExprConstant.cpp127
-rw-r--r--lib/CodeGen/CGRecordLayoutBuilder.cpp26
-rw-r--r--test/CodeGenCXX/pointers-to-data-members.cpp16
3 files changed, 155 insertions, 14 deletions
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 68b31aefa6..551a47aa9f 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -984,6 +984,79 @@ llvm::Constant *CodeGenModule::EmitConstantExpr(const Expr *E,
return C;
}
+static void
+FillInNullDataMemberPointers(CodeGenModule &CGM, QualType T,
+ std::vector<llvm::Constant *> &Elements,
+ uint64_t StartOffset) {
+ assert(StartOffset % 8 == 0 && "StartOffset not byte aligned!");
+
+ if (!CGM.getTypes().ContainsPointerToDataMember(T))
+ return;
+
+ if (const ConstantArrayType *CAT =
+ CGM.getContext().getAsConstantArrayType(T)) {
+ QualType ElementTy = CAT->getElementType();
+ uint64_t ElementSize = CGM.getContext().getTypeSize(ElementTy);
+
+ for (uint64_t I = 0, E = CAT->getSize().getZExtValue(); I != E; ++I) {
+ FillInNullDataMemberPointers(CGM, ElementTy, Elements,
+ StartOffset + I * ElementSize);
+ }
+ } else if (const RecordType *RT = T->getAs<RecordType>()) {
+ const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+ const ASTRecordLayout &Layout = CGM.getContext().getASTRecordLayout(RD);
+
+ // Go through all bases and fill in any null pointer to data members.
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ assert(!I->isVirtual() && "Should not see virtual bases here!");
+
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ // Ignore empty bases.
+ if (BaseDecl->isEmpty())
+ continue;
+
+ // Ignore bases that don't have any pointer to data members.
+ if (!CGM.getTypes().ContainsPointerToDataMember(BaseDecl))
+ continue;
+
+ uint64_t BaseOffset = Layout.getBaseClassOffset(BaseDecl);
+ FillInNullDataMemberPointers(CGM, I->getType(),
+ Elements, StartOffset + BaseOffset);
+ }
+
+ // Visit all fields.
+ unsigned FieldNo = 0;
+ for (RecordDecl::field_iterator I = RD->field_begin(),
+ E = RD->field_end(); I != E; ++I, ++FieldNo) {
+ QualType FieldType = I->getType();
+
+ if (!CGM.getTypes().ContainsPointerToDataMember(FieldType))
+ continue;
+
+ uint64_t FieldOffset = StartOffset + Layout.getFieldOffset(FieldNo);
+ FillInNullDataMemberPointers(CGM, FieldType, Elements, FieldOffset);
+ }
+ } else {
+ assert(T->isMemberPointerType() && "Should only see member pointers here!");
+ assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() &&
+ "Should only see pointers to data members here!");
+
+ uint64_t StartIndex = StartOffset / 8;
+ uint64_t EndIndex = StartIndex + CGM.getContext().getTypeSize(T) / 8;
+
+ llvm::Constant *NegativeOne =
+ llvm::ConstantInt::get(llvm::Type::getInt8Ty(CGM.getLLVMContext()),
+ -1ULL, /*isSigned=*/true);
+
+ // Fill in the null data member pointer.
+ for (uint64_t I = StartIndex; I != EndIndex; ++I)
+ Elements[I] = NegativeOne;
+ }
+}
+
llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
if (!getTypes().ContainsPointerToDataMember(T))
return llvm::Constant::getNullValue(getTypes().ConvertTypeForMem(T));
@@ -1005,21 +1078,60 @@ llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
if (const RecordType *RT = T->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
- assert(!RD->getNumBases() &&
- "FIXME: Handle zero-initializing structs with bases and "
- "pointers to data members.");
const llvm::StructType *STy =
cast<llvm::StructType>(getTypes().ConvertTypeForMem(T));
unsigned NumElements = STy->getNumElements();
std::vector<llvm::Constant *> Elements(NumElements);
+ const CGRecordLayout &Layout = getTypes().getCGRecordLayout(RD);
+
+ // Go through all bases and fill in any null pointer to data members.
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ assert(!I->isVirtual() && "Should not see virtual bases here!");
+
+ const CXXRecordDecl *BaseDecl =
+ cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
+
+ // Ignore empty bases.
+ if (BaseDecl->isEmpty())
+ continue;
+
+ // Ignore bases that don't have any pointer to data members.
+ if (!getTypes().ContainsPointerToDataMember(BaseDecl))
+ continue;
+
+ // Currently, all bases are arrays of i8. Figure out how many elements
+ // this base array has.
+ unsigned BaseFieldNo = Layout.getNonVirtualBaseLLVMFieldNo(BaseDecl);
+ const llvm::ArrayType *BaseArrayTy =
+ cast<llvm::ArrayType>(STy->getElementType(BaseFieldNo));
+
+ unsigned NumBaseElements = BaseArrayTy->getNumElements();
+ std::vector<llvm::Constant *> BaseElements(NumBaseElements);
+
+ // Now fill in null data member pointers.
+ FillInNullDataMemberPointers(*this, I->getType(), BaseElements, 0);
+
+ // Now go through all other elements and zero them out.
+ if (NumBaseElements) {
+ llvm::Constant *Zero =
+ llvm::ConstantInt::get(llvm::Type::getInt8Ty(getLLVMContext()), 0);
+
+ for (unsigned I = 0; I != NumBaseElements; ++I) {
+ if (!BaseElements[I])
+ BaseElements[I] = Zero;
+ }
+ }
+
+ Elements[BaseFieldNo] = llvm::ConstantArray::get(BaseArrayTy,
+ BaseElements);
+ }
+
for (RecordDecl::field_iterator I = RD->field_begin(),
E = RD->field_end(); I != E; ++I) {
const FieldDecl *FD = *I;
-
- const CGRecordLayout &RL =
- getTypes().getCGRecordLayout(FD->getParent());
- unsigned FieldNo = RL.getLLVMFieldNo(FD);
+ unsigned FieldNo = Layout.getLLVMFieldNo(FD);
Elements[FieldNo] = EmitNullConstant(FD->getType());
}
@@ -1032,6 +1144,7 @@ llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
return llvm::ConstantStruct::get(STy, Elements);
}
+ assert(T->isMemberPointerType() && "Should only see member pointers here!");
assert(!T->getAs<MemberPointerType>()->getPointeeType()->isFunctionType() &&
"Should only see pointers to data members here!");
diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index b1a2d51b66..c93e093a43 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -118,6 +118,7 @@ private:
/// CheckForPointerToDataMember - Check if the given type contains a pointer
/// to data member.
void CheckForPointerToDataMember(QualType T);
+ void CheckForPointerToDataMember(const CXXRecordDecl *RD);
public:
CGRecordLayoutBuilder(CodeGenTypes &Types)
@@ -456,6 +457,8 @@ void CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *BaseDecl,
return;
}
+ CheckForPointerToDataMember(BaseDecl);
+
// FIXME: Actually use a better type than [sizeof(BaseDecl) x i8] when we can.
AppendPadding(BaseOffset / 8, 1);
@@ -618,15 +621,24 @@ void CGRecordLayoutBuilder::CheckForPointerToDataMember(QualType T) {
} else if (const RecordType *RT = T->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
- // FIXME: It would be better if there was a way to explicitly compute the
- // record layout instead of converting to a type.
- Types.ConvertTagDeclType(RD);
+ return CheckForPointerToDataMember(RD);
+ }
+}
- const CGRecordLayout &Layout = Types.getCGRecordLayout(RD);
+void
+CGRecordLayoutBuilder::CheckForPointerToDataMember(const CXXRecordDecl *RD) {
+ // This record already contains a member pointer.
+ if (ContainsPointerToDataMember)
+ return;
- if (Layout.containsPointerToDataMember())
- ContainsPointerToDataMember = true;
- }
+ // FIXME: It would be better if there was a way to explicitly compute the
+ // record layout instead of converting to a type.
+ Types.ConvertTagDeclType(RD);
+
+ const CGRecordLayout &Layout = Types.getCGRecordLayout(RD);
+
+ if (Layout.containsPointerToDataMember())
+ ContainsPointerToDataMember = true;
}
CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D) {
diff --git a/test/CodeGenCXX/pointers-to-data-members.cpp b/test/CodeGenCXX/pointers-to-data-members.cpp
index 5ccf06e302..cab06dbd3d 100644
--- a/test/CodeGenCXX/pointers-to-data-members.cpp
+++ b/test/CodeGenCXX/pointers-to-data-members.cpp
@@ -35,6 +35,21 @@ namespace ZeroInit {
int A::*pa;
} s;
} ss;
+
+ struct A {
+ int A::*a;
+ int b;
+ };
+
+ struct B {
+ A a[10];
+ char c;
+ int B::*b;
+ };
+
+ struct C : A, B { int j; };
+ // CHECK: @_ZN8ZeroInit1cE = global %"struct.ZeroInit::C" { [16 x i8] c"\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00", [176 x i8] c"\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF", i32 0, [4 x i8] zeroinitializer }
+ C c;
}
// PR5674
@@ -102,3 +117,4 @@ struct A {
A::A() : a() {}
}
+
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-08-03 14:11:08 +0000