llvm-project/clang/lib/AST/InheritViz.cpp

//===- InheritViz.cpp - Graphviz visualization for inheritance --*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements CXXRecordDecl::viewInheritance, which
//  generates a GraphViz DOT file that depicts the class inheritance
//  diagram and then calls Graphviz/dot+gv on it.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/TypeOrdering.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/Support/GraphWriter.h"
#include <fstream>
#include <iterator>
#include <map>
#include <sstream>

using namespace llvm;

namespace clang {
  /// InheritanceGraphOutEdgeIterator - Enumerates the base classes
  /// based on base specifiers.
  class InheritanceGraphOutEdgeIterator {
    const CXXBaseSpecifier *Base;

  public:
    typedef const RecordType      *value_type;
    typedef const RecordType      *reference;
    typedef const RecordType     **pointer;
    typedef ptrdiff_t              difference_type;
    typedef std::forward_iterator_tag iterator_category;

    InheritanceGraphOutEdgeIterator(const CXXBaseSpecifier* Base = 0) 
      : Base(Base) { }

    reference operator*() const {
      assert(Base->getType()->getAsRecordType());
      return Base->getType()->getAsRecordType();
    }

    pointer operator->() const { return 0; }

    InheritanceGraphOutEdgeIterator& operator++() {
      ++Base;
      return *this;
    }

    InheritanceGraphOutEdgeIterator operator++(int) {
      return InheritanceGraphOutEdgeIterator(Base++);
    }
    
    friend bool operator==(InheritanceGraphOutEdgeIterator const& x,
                           InheritanceGraphOutEdgeIterator const& y) {
      return x.Base == y.Base;
    }

    friend bool operator!=(InheritanceGraphOutEdgeIterator const& x,
                           InheritanceGraphOutEdgeIterator const& y) {
      return x.Base != y.Base;
    }
  };

} // end namespace clang

namespace llvm {
  template<> struct GraphTraits<const clang::RecordType *> {
    typedef const clang::RecordType                      NodeType;
    typedef clang::InheritanceGraphOutEdgeIterator       ChildIteratorType;
    typedef llvm::df_iterator<const clang::RecordType *> nodes_iterator;

    static const NodeType *getEntryNode(const clang::RecordType *Type) {
      return Type;
    }

    static ChildIteratorType child_begin(const clang::RecordType *Type) {
      const clang::CXXRecordDecl *Decl 
        = dyn_cast_or_null<clang::CXXRecordDecl>(Type->getDecl());
      if (Decl->getNumBases() == 0)
        return clang::InheritanceGraphOutEdgeIterator(0);
      else
        return clang::InheritanceGraphOutEdgeIterator(Decl->getBase(0));
    }
    static ChildIteratorType child_end(const clang::RecordType *Type) {
      const clang::CXXRecordDecl *Decl 
        = dyn_cast_or_null<clang::CXXRecordDecl>(Type->getDecl());
      if (Decl->getNumBases() == 0)
        return clang::InheritanceGraphOutEdgeIterator(0);
      else
        return clang::InheritanceGraphOutEdgeIterator(Decl->getBase(0) + 
                                                      Decl->getNumBases());
    }

    static nodes_iterator nodes_begin(const clang::RecordType *Type) {
      return df_begin(Type);
    }
    
    static nodes_iterator nodes_end(const clang::RecordType *Type) {
      return df_end(Type);
    }
  };
}

namespace clang {

/// InheritanceHierarchyWriter - Helper class that writes out a
/// GraphViz file that diagrams the inheritance hierarchy starting at
/// a given C++ class type. Note that we do not use LLVM's
/// GraphWriter, because the interface does not permit us to properly
/// differentiate between uses of types as virtual bases
/// vs. non-virtual bases.
class InheritanceHierarchyWriter {
  ASTContext& Context;
  std::ostream &Out;
  std::map<QualType, int, QualTypeOrdering> DirectBaseCount;
  std::set<QualType, QualTypeOrdering> KnownVirtualBases;

public:
  InheritanceHierarchyWriter(ASTContext& Context, std::ostream& Out)
    : Context(Context), Out(Out) { }

  void WriteGraph(QualType Type) {
    Out << "digraph \"" << DOT::EscapeString(Type.getAsString()) << "\" {\n";
    WriteNode(Type, false);
    Out << "}\n";
  }

protected:
  /// WriteNode - Write out the description of node in the inheritance
  /// diagram, which may be a base class or it may be the root node.
  void WriteNode(QualType Type, bool FromVirtual);

  /// WriteNodeReference - Write out a reference to the given node,
  /// using a unique identifier for each direct base and for the
  /// (only) virtual base.
  std::ostream& WriteNodeReference(QualType Type, bool FromVirtual);
};

void InheritanceHierarchyWriter::WriteNode(QualType Type, bool FromVirtual) {
  QualType CanonType = Context.getCanonicalType(Type);

  if (FromVirtual) {
    if (KnownVirtualBases.find(CanonType) != KnownVirtualBases.end())
      return;

    // We haven't seen this virtual base before, so display it and
    // its bases.
    KnownVirtualBases.insert(CanonType);
  }

  // Declare the node itself.
  Out << "  ";
  WriteNodeReference(Type, FromVirtual);

  // Give the node a label based on the name of the class.
  std::string TypeName = Type.getAsString();
  Out << " [ shape=\"box\", label=\"" << DOT::EscapeString(TypeName);

  // If the name of the class was a typedef or something different
  // from the "real" class name, show the real class name in
  // parentheses so we don't confuse ourselves.
  if (TypeName != CanonType.getAsString()) {
    Out << "\\n(" << CanonType.getAsString() << ")";
  }

  // Finished describing the node.
  Out << " \"];\n";

  // Display the base classes.
  const CXXRecordDecl *Decl 
    = static_cast<const CXXRecordDecl *>(Type->getAsRecordType()->getDecl());
  for (unsigned idx = 0; idx < Decl->getNumBases(); ++idx) {
    const CXXBaseSpecifier *Base = Decl->getBase(idx);
    QualType CanonBaseType = Context.getCanonicalType(Base->getType());

    // If this is not virtual inheritance, bump the direct base
    // count for the type.
    if (!Base->isVirtual())
      ++DirectBaseCount[CanonBaseType];

    // Write out the node (if we need to).
    WriteNode(Base->getType(), Base->isVirtual());

    // Write out the edge.
    Out << "  ";
    WriteNodeReference(Type, FromVirtual);
    Out << " -> ";
    WriteNodeReference(Base->getType(), Base->isVirtual());

    // Write out edge attributes to show the kind of inheritance.
    if (Base->isVirtual()) {
      Out << " [ style=\"dashed\" ]";
    }
    Out << ";";
  }
}

/// WriteNodeReference - Write out a reference to the given node,
/// using a unique identifier for each direct base and for the
/// (only) virtual base.
std::ostream& 
InheritanceHierarchyWriter::WriteNodeReference(QualType Type, 
                                               bool FromVirtual) {
  QualType CanonType = Context.getCanonicalType(Type);

  Out << "Class_" << CanonType.getAsOpaquePtr();
  if (!FromVirtual)
    Out << "_" << DirectBaseCount[CanonType];
  return Out;
}

/// viewInheritance - Display the inheritance hierarchy of this C++
/// class using GraphViz.
void QualType::viewInheritance(ASTContext& Context) {
  if (!(*this)->getAsRecordType()) {
    cerr << "Type " << getAsString() << " is not a C++ class type.\n";
  }
#ifndef NDEBUG
  //  std::string Title = "Inheritance graph for " + getAsString();
  //  llvm::ViewGraph((*this)->getAsRecordType(), Title.c_str());
  std::string ErrMsg;
  sys::Path Filename = sys::Path::GetTemporaryDirectory(&ErrMsg);
  if (Filename.isEmpty()) {
    cerr << "Error: " << ErrMsg << "\n";
    return;
  }
  Filename.appendComponent(getAsString() + ".dot");
  if (Filename.makeUnique(true,&ErrMsg)) {
    cerr << "Error: " << ErrMsg << "\n";
    return;
  }

  cerr << "Writing '" << Filename << "'... ";

  std::ofstream O(Filename.c_str());

  if (O.good()) {
    InheritanceHierarchyWriter Writer(Context, O);
    Writer.WriteGraph(*this);
    cerr << " done. \n";

    O.close();

    // Display the graph
    DisplayGraph(Filename);
  } else {
    cerr << "error opening file for writing!\n";
    Filename.clear();
  }
#else
  cerr << "QualType::viewInheritance is only available in debug "
       << "builds on systems with Graphviz or gv!\n";
#endif
}

}