================ @@ -0,0 +1,105 @@ +//===---------- SubobjectVisitor.h - Subobject Visitor ----------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file defines the SubobjectVisitor interface, which recursively +// traverses subobjects within a type. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_AST_SUBOBJECTVISITOR_H +#define LLVM_CLANG_AST_SUBOBJECTVISITOR_H + +#include "clang/AST/Type.h" + +namespace clang { + +/// Given a type, subobject visitors visit all subobjects of the type in depth +/// first order. Both pre-order and post-order visitation are performed so that +/// derived classes can maintain an access path to the visited elements. +/// Subobjects include all base classes and non-static data members, including +/// those that are not subobjects according to the C++standard like data +/// members with a reference type. Virtual base classes are visited each time +/// they appear in a class hierarchy despite there being only one actual +/// subobject present in an object of a most derived type. Array elements are +/// not individually visited; only their containing array is. +template <template <typename> class Ptr, typename Derived> +class SubobjectVisitorBase { + ASTContext &Ctx; + template <typename Class> using ptr_t = typename Ptr<Class>::type; + +public: + SubobjectVisitorBase(ASTContext &Ctx) : Ctx(Ctx) {} + + /// Return a reference to the derived class. + Derived &getDerived() { return *static_cast<Derived *>(this); } + + void visit(QualType QT) { + // If the type is an array, visit its element type. Separate traversal of + // arrays is not needed because the array will be encountered as a + // FieldDecl. + + if (QT->isArrayType()) { + QualType ElTy = + cast<ConstantArrayType>(Ctx.getAsArrayType(QT))->getElementType(); + getDerived().visit(ElTy); + return; + } + + if (ptr_t<RecordDecl> RD = QT->getAsRecordDecl()) { ---------------- tahonermann wrote:
Good catch! `getAsRecordDecl()` will only succeed for `Type` classes that derive from `TagType`. I think we should recurse through `AtomicType::getValueType()`. I think we should be ignoring sugar types as well; perhaps the first thing this function should do is `QT = QT.desugar()`. This would suffice to handle `AttributedType`. Do any of the vector type classes (`VectorType`, `ExtVectorType`, `MatrixType`) support a structured element type? Does `ComplexType`? My recollection is that these all require a fundamental type as their element type. I think we should not recurse through Objective-C structural types; if I remember correctly, their allocation model effectively prohibits them from ever being considered subobjects. https://github.com/llvm/llvm-project/pull/192957 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
