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//===- InheritViz.cpp - Graphviz visualization for inheritance --*- 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 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/Support/FileSystem.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
#include <set>
using namespace clang;
namespace {
/// 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;
raw_ostream &Out;
std::map<QualType, int, QualTypeOrdering> DirectBaseCount;
std::set<QualType, QualTypeOrdering> KnownVirtualBases;
public:
InheritanceHierarchyWriter(ASTContext& Context, raw_ostream& Out)
: Context(Context), Out(Out) { }
void WriteGraph(QualType Type) {
Out << "digraph \"" << llvm::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.
raw_ostream& WriteNodeReference(QualType Type, bool FromVirtual);
};
} // namespace
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=\"" << llvm::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 auto *Decl =
static_cast<const CXXRecordDecl *>(Type->castAs<RecordType>()->getDecl());
for (const auto &Base : Decl->bases()) {
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.
raw_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 CXXRecordDecl::viewInheritance(ASTContext& Context) const {
QualType Self = Context.getTypeDeclType(this);
int FD;
SmallString<128> Filename;
if (std::error_code EC = llvm::sys::fs::createTemporaryFile(
Self.getAsString(), "dot", FD, Filename)) {
llvm::errs() << "Error: " << EC.message() << "\n";
return;
}
llvm::errs() << "Writing '" << Filename << "'... ";
llvm::raw_fd_ostream O(FD, true);
InheritanceHierarchyWriter Writer(Context, O);
Writer.WriteGraph(Self);
llvm::errs() << " done. \n";
O.close();
// Display the graph
DisplayGraph(Filename);
}