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      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>
     25 
     26 using namespace llvm;
     27 
     28 namespace clang {
     29 
     30 /// InheritanceHierarchyWriter - Helper class that writes out a
     31 /// GraphViz file that diagrams the inheritance hierarchy starting at
     32 /// a given C++ class type. Note that we do not use LLVM's
     33 /// GraphWriter, because the interface does not permit us to properly
     34 /// differentiate between uses of types as virtual bases
     35 /// vs. non-virtual bases.
     36 class InheritanceHierarchyWriter {
     37   ASTContext& Context;
     38   raw_ostream &Out;
     39   std::map<QualType, int, QualTypeOrdering> DirectBaseCount;
     40   std::set<QualType, QualTypeOrdering> KnownVirtualBases;
     41 
     42 public:
     43   InheritanceHierarchyWriter(ASTContext& Context, raw_ostream& Out)
     44     : Context(Context), Out(Out) { }
     45 
     46   void WriteGraph(QualType Type) {
     47     Out << "digraph \"" << DOT::EscapeString(Type.getAsString()) << "\" {\n";
     48     WriteNode(Type, false);
     49     Out << "}\n";
     50   }
     51 
     52 protected:
     53   /// WriteNode - Write out the description of node in the inheritance
     54   /// diagram, which may be a base class or it may be the root node.
     55   void WriteNode(QualType Type, bool FromVirtual);
     56 
     57   /// WriteNodeReference - Write out a reference to the given node,
     58   /// using a unique identifier for each direct base and for the
     59   /// (only) virtual base.
     60   raw_ostream& WriteNodeReference(QualType Type, bool FromVirtual);
     61 };
     62 
     63 void 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=\"" << 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 (CXXRecordDecl::base_class_const_iterator Base = Decl->bases_begin();
     97        Base != Decl->bases_end(); ++Base) {
     98     QualType CanonBaseType = Context.getCanonicalType(Base->getType());
     99 
    100     // If this is not virtual inheritance, bump the direct base
    101     // count for the type.
    102     if (!Base->isVirtual())
    103       ++DirectBaseCount[CanonBaseType];
    104 
    105     // Write out the node (if we need to).
    106     WriteNode(Base->getType(), Base->isVirtual());
    107 
    108     // Write out the edge.
    109     Out << "  ";
    110     WriteNodeReference(Type, FromVirtual);
    111     Out << " -> ";
    112     WriteNodeReference(Base->getType(), Base->isVirtual());
    113 
    114     // Write out edge attributes to show the kind of inheritance.
    115     if (Base->isVirtual()) {
    116       Out << " [ style=\"dashed\" ]";
    117     }
    118     Out << ";";
    119   }
    120 }
    121 
    122 /// WriteNodeReference - Write out a reference to the given node,
    123 /// using a unique identifier for each direct base and for the
    124 /// (only) virtual base.
    125 raw_ostream&
    126 InheritanceHierarchyWriter::WriteNodeReference(QualType Type,
    127                                                bool FromVirtual) {
    128   QualType CanonType = Context.getCanonicalType(Type);
    129 
    130   Out << "Class_" << CanonType.getAsOpaquePtr();
    131   if (!FromVirtual)
    132     Out << "_" << DirectBaseCount[CanonType];
    133   return Out;
    134 }
    135 
    136 /// viewInheritance - Display the inheritance hierarchy of this C++
    137 /// class using GraphViz.
    138 void CXXRecordDecl::viewInheritance(ASTContext& Context) const {
    139   QualType Self = Context.getTypeDeclType(this);
    140 
    141   int FD;
    142   SmallString<128> Filename;
    143   error_code EC =
    144       sys::fs::createTemporaryFile(Self.getAsString(), "dot", FD, Filename);
    145   if (EC) {
    146     llvm::errs() << "Error: " << EC.message() << "\n";
    147     return;
    148   }
    149 
    150   llvm::errs() << "Writing '" << Filename << "'... ";
    151 
    152   llvm::raw_fd_ostream O(FD, true);
    153 
    154   InheritanceHierarchyWriter Writer(Context, O);
    155   Writer.WriteGraph(Self);
    156   llvm::errs() << " done. \n";
    157 
    158   O.close();
    159 
    160   // Display the graph
    161   DisplayGraph(Filename);
    162 }
    163 
    164 }
    165