1//===- InheritViz.cpp - Graphviz visualization for inheritance --*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements CXXRecordDecl::viewInheritance, which
11//  generates a GraphViz DOT file that depicts the class inheritance
12//  diagram and then calls Graphviz/dot+gv on it.
13//
14//===----------------------------------------------------------------------===//
15
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/Decl.h"
18#include "clang/AST/DeclCXX.h"
19#include "clang/AST/TypeOrdering.h"
20#include "llvm/Support/FileSystem.h"
21#include "llvm/Support/GraphWriter.h"
22#include "llvm/Support/raw_ostream.h"
23#include <map>
24#include <set>
25using namespace clang;
26
27namespace {
28/// InheritanceHierarchyWriter - Helper class that writes out a
29/// GraphViz file that diagrams the inheritance hierarchy starting at
30/// a given C++ class type. Note that we do not use LLVM's
31/// GraphWriter, because the interface does not permit us to properly
32/// differentiate between uses of types as virtual bases
33/// vs. non-virtual bases.
34class InheritanceHierarchyWriter {
35  ASTContext& Context;
36  raw_ostream &Out;
37  std::map<QualType, int, QualTypeOrdering> DirectBaseCount;
38  std::set<QualType, QualTypeOrdering> KnownVirtualBases;
39
40public:
41  InheritanceHierarchyWriter(ASTContext& Context, raw_ostream& Out)
42    : Context(Context), Out(Out) { }
43
44  void WriteGraph(QualType Type) {
45    Out << "digraph \"" << llvm::DOT::EscapeString(Type.getAsString())
46        << "\" {\n";
47    WriteNode(Type, false);
48    Out << "}\n";
49  }
50
51protected:
52  /// WriteNode - Write out the description of node in the inheritance
53  /// diagram, which may be a base class or it may be the root node.
54  void WriteNode(QualType Type, bool FromVirtual);
55
56  /// WriteNodeReference - Write out a reference to the given node,
57  /// using a unique identifier for each direct base and for the
58  /// (only) virtual base.
59  raw_ostream& WriteNodeReference(QualType Type, bool FromVirtual);
60};
61} // namespace
62
63void InheritanceHierarchyWriter::WriteNode(QualType Type, bool FromVirtual) {
64  QualType CanonType = Context.getCanonicalType(Type);
65
66  if (FromVirtual) {
67    if (KnownVirtualBases.find(CanonType) != KnownVirtualBases.end())
68      return;
69
70    // We haven't seen this virtual base before, so display it and
71    // its bases.
72    KnownVirtualBases.insert(CanonType);
73  }
74
75  // Declare the node itself.
76  Out << "  ";
77  WriteNodeReference(Type, FromVirtual);
78
79  // Give the node a label based on the name of the class.
80  std::string TypeName = Type.getAsString();
81  Out << " [ shape=\"box\", label=\"" << llvm::DOT::EscapeString(TypeName);
82
83  // If the name of the class was a typedef or something different
84  // from the "real" class name, show the real class name in
85  // parentheses so we don't confuse ourselves.
86  if (TypeName != CanonType.getAsString()) {
87    Out << "\\n(" << CanonType.getAsString() << ")";
88  }
89
90  // Finished describing the node.
91  Out << " \"];\n";
92
93  // Display the base classes.
94  const CXXRecordDecl *Decl
95    = static_cast<const CXXRecordDecl *>(Type->getAs<RecordType>()->getDecl());
96  for (const auto &Base : Decl->bases()) {
97    QualType CanonBaseType = Context.getCanonicalType(Base.getType());
98
99    // If this is not virtual inheritance, bump the direct base
100    // count for the type.
101    if (!Base.isVirtual())
102      ++DirectBaseCount[CanonBaseType];
103
104    // Write out the node (if we need to).
105    WriteNode(Base.getType(), Base.isVirtual());
106
107    // Write out the edge.
108    Out << "  ";
109    WriteNodeReference(Type, FromVirtual);
110    Out << " -> ";
111    WriteNodeReference(Base.getType(), Base.isVirtual());
112
113    // Write out edge attributes to show the kind of inheritance.
114    if (Base.isVirtual()) {
115      Out << " [ style=\"dashed\" ]";
116    }
117    Out << ";";
118  }
119}
120
121/// WriteNodeReference - Write out a reference to the given node,
122/// using a unique identifier for each direct base and for the
123/// (only) virtual base.
124raw_ostream&
125InheritanceHierarchyWriter::WriteNodeReference(QualType Type,
126                                               bool FromVirtual) {
127  QualType CanonType = Context.getCanonicalType(Type);
128
129  Out << "Class_" << CanonType.getAsOpaquePtr();
130  if (!FromVirtual)
131    Out << "_" << DirectBaseCount[CanonType];
132  return Out;
133}
134
135/// viewInheritance - Display the inheritance hierarchy of this C++
136/// class using GraphViz.
137void CXXRecordDecl::viewInheritance(ASTContext& Context) const {
138  QualType Self = Context.getTypeDeclType(this);
139
140  int FD;
141  SmallString<128> Filename;
142  if (std::error_code EC = llvm::sys::fs::createTemporaryFile(
143          Self.getAsString(), "dot", FD, Filename)) {
144    llvm::errs() << "Error: " << EC.message() << "\n";
145    return;
146  }
147
148  llvm::errs() << "Writing '" << Filename << "'... ";
149
150  llvm::raw_fd_ostream O(FD, true);
151
152  InheritanceHierarchyWriter Writer(Context, O);
153  Writer.WriteGraph(Self);
154  llvm::errs() << " done. \n";
155
156  O.close();
157
158  // Display the graph
159  DisplayGraph(Filename);
160}
161