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[lldb] Use early returns in TypeSystemClang::IsPossibleDynamicType #137630

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Apr 29, 2025
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[lldb] Use early returns in TypeSystemClang::IsPossibleDynamicType #137630

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197 changes: 88 additions & 109 deletions lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3579,129 +3579,108 @@ bool TypeSystemClang::IsPossibleDynamicType(lldb::opaque_compiler_type_t type,
CompilerType *dynamic_pointee_type,
bool check_cplusplus,
bool check_objc) {
if (dynamic_pointee_type)
dynamic_pointee_type->Clear();
if (!type)
return false;

auto set_dynamic_pointee_type = [&](clang::QualType type) {
if (dynamic_pointee_type)
dynamic_pointee_type->SetCompilerType(weak_from_this(),
type.getAsOpaquePtr());
};

clang::QualType pointee_qual_type;
if (type) {
clang::QualType qual_type = RemoveWrappingTypes(GetCanonicalQualType(type));
bool success = false;
const clang::Type::TypeClass type_class = qual_type->getTypeClass();
switch (type_class) {
case clang::Type::Builtin:
if (check_objc &&
llvm::cast<clang::BuiltinType>(qual_type)->getKind() ==
clang::BuiltinType::ObjCId) {
if (dynamic_pointee_type)
dynamic_pointee_type->SetCompilerType(weak_from_this(), type);
return true;
}
break;
clang::QualType qual_type = RemoveWrappingTypes(GetCanonicalQualType(type));
switch (qual_type->getTypeClass()) {
case clang::Type::Builtin:
if (check_objc && llvm::cast<clang::BuiltinType>(qual_type)->getKind() ==
clang::BuiltinType::ObjCId) {
set_dynamic_pointee_type(qual_type);
return true;
}
return false;

case clang::Type::ObjCObjectPointer:
if (check_objc) {
if (const auto *objc_pointee_type =
qual_type->getPointeeType().getTypePtrOrNull()) {
if (const auto *objc_object_type =
llvm::dyn_cast_or_null<clang::ObjCObjectType>(
objc_pointee_type)) {
if (objc_object_type->isObjCClass())
return false;
}
}
if (dynamic_pointee_type)
dynamic_pointee_type->SetCompilerType(
weak_from_this(),
llvm::cast<clang::ObjCObjectPointerType>(qual_type)
->getPointeeType()
.getAsOpaquePtr());
return true;
case clang::Type::ObjCObjectPointer:
if (!check_objc)
return false;
if (const auto *objc_pointee_type =
qual_type->getPointeeType().getTypePtrOrNull()) {
if (const auto *objc_object_type =
llvm::dyn_cast_or_null<clang::ObjCObjectType>(
objc_pointee_type)) {
if (objc_object_type->isObjCClass())
return false;
}
break;
}
set_dynamic_pointee_type(
llvm::cast<clang::ObjCObjectPointerType>(qual_type)->getPointeeType());
return true;

case clang::Type::Pointer:
pointee_qual_type =
llvm::cast<clang::PointerType>(qual_type)->getPointeeType();
success = true;
break;
case clang::Type::Pointer:
pointee_qual_type =
llvm::cast<clang::PointerType>(qual_type)->getPointeeType();
break;

case clang::Type::LValueReference:
case clang::Type::RValueReference:
pointee_qual_type =
llvm::cast<clang::ReferenceType>(qual_type)->getPointeeType();
success = true;
break;
case clang::Type::LValueReference:
case clang::Type::RValueReference:
pointee_qual_type =
llvm::cast<clang::ReferenceType>(qual_type)->getPointeeType();
break;

default:
return false;
}

// Check to make sure what we are pointing to is a possible dynamic C++ type
// We currently accept any "void *" (in case we have a class that has been
// watered down to an opaque pointer) and virtual C++ classes.
switch (pointee_qual_type.getCanonicalType()->getTypeClass()) {
case clang::Type::Builtin:
switch (llvm::cast<clang::BuiltinType>(pointee_qual_type)->getKind()) {
case clang::BuiltinType::UnknownAny:
case clang::BuiltinType::Void:
set_dynamic_pointee_type(pointee_qual_type);
return true;
default:
break;
return false;
}

if (success) {
// Check to make sure what we are pointing too is a possible dynamic C++
// type We currently accept any "void *" (in case we have a class that
// has been watered down to an opaque pointer) and virtual C++ classes.
const clang::Type::TypeClass pointee_type_class =
pointee_qual_type.getCanonicalType()->getTypeClass();
switch (pointee_type_class) {
case clang::Type::Builtin:
switch (llvm::cast<clang::BuiltinType>(pointee_qual_type)->getKind()) {
case clang::BuiltinType::UnknownAny:
case clang::BuiltinType::Void:
if (dynamic_pointee_type)
dynamic_pointee_type->SetCompilerType(
weak_from_this(), pointee_qual_type.getAsOpaquePtr());
return true;
default:
break;
}
break;

case clang::Type::Record:
if (check_cplusplus) {
clang::CXXRecordDecl *cxx_record_decl =
pointee_qual_type->getAsCXXRecordDecl();
if (cxx_record_decl) {
bool is_complete = cxx_record_decl->isCompleteDefinition();

if (is_complete)
success = cxx_record_decl->isDynamicClass();
else {
if (std::optional<ClangASTMetadata> metadata =
GetMetadata(cxx_record_decl))
success = metadata->GetIsDynamicCXXType();
else {
is_complete = GetType(pointee_qual_type).GetCompleteType();
if (is_complete)
success = cxx_record_decl->isDynamicClass();
else
success = false;
}
}
case clang::Type::Record: {
if (!check_cplusplus)
return false;
clang::CXXRecordDecl *cxx_record_decl =
pointee_qual_type->getAsCXXRecordDecl();
if (!cxx_record_decl)
return false;

if (success) {
if (dynamic_pointee_type)
dynamic_pointee_type->SetCompilerType(
weak_from_this(), pointee_qual_type.getAsOpaquePtr());
return true;
}
}
}
break;
bool success;
if (cxx_record_decl->isCompleteDefinition())
success = cxx_record_decl->isDynamicClass();
else if (std::optional<ClangASTMetadata> metadata =
GetMetadata(cxx_record_decl))
success = metadata->GetIsDynamicCXXType();
Comment on lines +3660 to +3662
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This is the problematic part -- since we stopped searching for definitions eagerly, ClangASTMetadata::GetIsDynamicCXXType does not (always) hold the correct answer to this question.

else if (GetType(pointee_qual_type).GetCompleteType())
success = cxx_record_decl->isDynamicClass();
else
success = false;

case clang::Type::ObjCObject:
case clang::Type::ObjCInterface:
if (check_objc) {
if (dynamic_pointee_type)
dynamic_pointee_type->SetCompilerType(
weak_from_this(), pointee_qual_type.getAsOpaquePtr());
return true;
}
break;
if (success)
set_dynamic_pointee_type(pointee_qual_type);
return success;
}

default:
break;
}
case clang::Type::ObjCObject:
case clang::Type::ObjCInterface:
if (check_objc) {
set_dynamic_pointee_type(pointee_qual_type);
return true;
}
break;

default:
break;
}
if (dynamic_pointee_type)
dynamic_pointee_type->Clear();
return false;
}

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