159 lines · cpp
1//===- InheritViz.cpp - Graphviz visualization for inheritance --*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements CXXRecordDecl::viewInheritance, which10// generates a GraphViz DOT file that depicts the class inheritance11// diagram and then calls Graphviz/dot+gv on it.12//13//===----------------------------------------------------------------------===//14 15#include "clang/AST/ASTContext.h"16#include "clang/AST/Decl.h"17#include "clang/AST/DeclCXX.h"18#include "clang/AST/TypeOrdering.h"19#include "llvm/Support/FileSystem.h"20#include "llvm/Support/GraphWriter.h"21#include "llvm/Support/raw_ostream.h"22#include <map>23#include <set>24using namespace clang;25 26namespace {27/// InheritanceHierarchyWriter - Helper class that writes out a28/// GraphViz file that diagrams the inheritance hierarchy starting at29/// a given C++ class type. Note that we do not use LLVM's30/// GraphWriter, because the interface does not permit us to properly31/// differentiate between uses of types as virtual bases32/// vs. non-virtual bases.33class InheritanceHierarchyWriter {34 ASTContext& Context;35 raw_ostream &Out;36 std::map<QualType, int, QualTypeOrdering> DirectBaseCount;37 std::set<QualType, QualTypeOrdering> KnownVirtualBases;38 39public:40 InheritanceHierarchyWriter(ASTContext& Context, raw_ostream& Out)41 : Context(Context), Out(Out) { }42 43 void WriteGraph(QualType Type) {44 Out << "digraph \"" << llvm::DOT::EscapeString(Type.getAsString())45 << "\" {\n";46 WriteNode(Type, false);47 Out << "}\n";48 }49 50protected:51 /// WriteNode - Write out the description of node in the inheritance52 /// diagram, which may be a base class or it may be the root node.53 void WriteNode(QualType Type, bool FromVirtual);54 55 /// WriteNodeReference - Write out a reference to the given node,56 /// using a unique identifier for each direct base and for the57 /// (only) virtual base.58 raw_ostream& WriteNodeReference(QualType Type, bool FromVirtual);59};60} // namespace61 62void InheritanceHierarchyWriter::WriteNode(QualType Type, bool FromVirtual) {63 QualType CanonType = Context.getCanonicalType(Type);64 65 if (FromVirtual) {66 if (!KnownVirtualBases.insert(CanonType).second)67 return;68 69 // We haven't seen this virtual base before, so display it and70 // its bases.71 }72 73 // Declare the node itself.74 Out << " ";75 WriteNodeReference(Type, FromVirtual);76 77 // Give the node a label based on the name of the class.78 std::string TypeName = Type.getAsString();79 Out << " [ shape=\"box\", label=\"" << llvm::DOT::EscapeString(TypeName);80 81 // If the name of the class was a typedef or something different82 // from the "real" class name, show the real class name in83 // parentheses so we don't confuse ourselves.84 if (TypeName != CanonType.getAsString()) {85 Out << "\\n(" << CanonType.getAsString() << ")";86 }87 88 // Finished describing the node.89 Out << " \"];\n";90 91 // Display the base classes.92 const auto *Decl =93 cast<CXXRecordDecl>(Type->castAsCanonical<RecordType>()->getDecl());94 for (const auto &Base : Decl->bases()) {95 QualType CanonBaseType = Context.getCanonicalType(Base.getType());96 97 // If this is not virtual inheritance, bump the direct base98 // count for the type.99 if (!Base.isVirtual())100 ++DirectBaseCount[CanonBaseType];101 102 // Write out the node (if we need to).103 WriteNode(Base.getType(), Base.isVirtual());104 105 // Write out the edge.106 Out << " ";107 WriteNodeReference(Type, FromVirtual);108 Out << " -> ";109 WriteNodeReference(Base.getType(), Base.isVirtual());110 111 // Write out edge attributes to show the kind of inheritance.112 if (Base.isVirtual()) {113 Out << " [ style=\"dashed\" ]";114 }115 Out << ";";116 }117}118 119/// WriteNodeReference - Write out a reference to the given node,120/// using a unique identifier for each direct base and for the121/// (only) virtual base.122raw_ostream&123InheritanceHierarchyWriter::WriteNodeReference(QualType Type,124 bool FromVirtual) {125 QualType CanonType = Context.getCanonicalType(Type);126 127 Out << "Class_" << CanonType.getAsOpaquePtr();128 if (!FromVirtual)129 Out << "_" << DirectBaseCount[CanonType];130 return Out;131}132 133/// viewInheritance - Display the inheritance hierarchy of this C++134/// class using GraphViz.135void CXXRecordDecl::viewInheritance(ASTContext& Context) const {136 QualType Self = Context.getCanonicalTagType(this);137 138 int FD;139 SmallString<128> Filename;140 if (std::error_code EC = llvm::sys::fs::createTemporaryFile(141 Self.getAsString(), "dot", FD, Filename)) {142 llvm::errs() << "Error: " << EC.message() << "\n";143 return;144 }145 146 llvm::errs() << "Writing '" << Filename << "'... ";147 148 llvm::raw_fd_ostream O(FD, true);149 150 InheritanceHierarchyWriter Writer(Context, O);151 Writer.WriteGraph(Self);152 llvm::errs() << " done. \n";153 154 O.close();155 156 // Display the graph157 DisplayGraph(Filename);158}159