llvm-6502/include/llvm/ADT/GraphTraits.h
Duncan Sands 4a20c7a0a9 1. Allow SCCIterator to work with GraphT types that are constant.
2.  Allow SCCIterator to work with inverse graphs.
3.  Fix an incorrect comment in GraphTraits.h (the type in the comment 
was given as GraphType* when it is actually const GraphType &).
Patch by Patrick Alexander Simmons.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89091 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-17 10:54:25 +00:00

104 lines
3.4 KiB
C++

//===-- llvm/ADT/GraphTraits.h - Graph traits template ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the little GraphTraits<X> template class that should be
// specialized by classes that want to be iteratable by generic graph iterators.
//
// This file also defines the marker class Inverse that is used to iterate over
// graphs in a graph defined, inverse ordering...
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_GRAPHTRAITS_H
#define LLVM_ADT_GRAPHTRAITS_H
namespace llvm {
// GraphTraits - This class should be specialized by different graph types...
// which is why the default version is empty.
//
template<class GraphType>
struct GraphTraits {
// Elements to provide:
// typedef NodeType - Type of Node in the graph
// typedef ChildIteratorType - Type used to iterate over children in graph
// static NodeType *getEntryNode(const GraphType &)
// Return the entry node of the graph
// static ChildIteratorType child_begin(NodeType *)
// static ChildIteratorType child_end (NodeType *)
// Return iterators that point to the beginning and ending of the child
// node list for the specified node.
//
// typedef ...iterator nodes_iterator;
// static nodes_iterator nodes_begin(GraphType *G)
// static nodes_iterator nodes_end (GraphType *G)
//
// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
// If anyone tries to use this class without having an appropriate
// specialization, make an error. If you get this error, it's because you
// need to include the appropriate specialization of GraphTraits<> for your
// graph, or you need to define it for a new graph type. Either that or
// your argument to XXX_begin(...) is unknown or needs to have the proper .h
// file #include'd.
//
typedef typename GraphType::UnknownGraphTypeError NodeType;
};
// Inverse - This class is used as a little marker class to tell the graph
// iterator to iterate over the graph in a graph defined "Inverse" ordering.
// Not all graphs define an inverse ordering, and if they do, it depends on
// the graph exactly what that is. Here's an example of usage with the
// df_iterator:
//
// idf_iterator<Method*> I = idf_begin(M), E = idf_end(M);
// for (; I != E; ++I) { ... }
//
// Which is equivalent to:
// df_iterator<Inverse<Method*> > I = idf_begin(M), E = idf_end(M);
// for (; I != E; ++I) { ... }
//
template <class GraphType>
struct Inverse {
const GraphType &Graph;
inline Inverse(const GraphType &G) : Graph(G) {}
};
// Provide a partial specialization of GraphTraits so that the inverse of an
// inverse falls back to the original graph.
template<class T>
struct GraphTraits<Inverse<Inverse<T> > > {
typedef typename GraphTraits<T>::NodeType NodeType;
typedef typename GraphTraits<T>::ChildIteratorType ChildIteratorType;
static NodeType *getEntryNode(Inverse<Inverse<T> > *G) {
return GraphTraits<T>::getEntryNode(G->Graph.Graph);
}
static ChildIteratorType child_begin(NodeType* N) {
return GraphTraits<T>::child_begin(N);
}
static ChildIteratorType child_end(NodeType* N) {
return GraphTraits<T>::child_end(N);
}
};
} // End llvm namespace
#endif