6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
171 lines
6.9 KiB
C++
171 lines
6.9 KiB
C++
//===- llvm/ADT/GraphTraits.h - Graph traits template -----------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// This file defines the little GraphTraits<X> template class that should be
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/// specialized by classes that want to be iteratable by generic graph
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/// iterators.
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///
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/// This file also defines the marker class Inverse that is used to iterate over
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/// graphs in a graph defined, inverse ordering...
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ADT_GRAPHTRAITS_H
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#define LLVM_ADT_GRAPHTRAITS_H
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/iterator_range.h"
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namespace llvm {
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// GraphTraits - This class should be specialized by different graph types...
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// which is why the default version is empty.
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//
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// This template evolved from supporting `BasicBlock` to also later supporting
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// more complex types (e.g. CFG and DomTree).
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//
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// GraphTraits can be used to create a view over a graph interpreting it
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// differently without requiring a copy of the original graph. This could
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// be achieved by carrying more data in NodeRef. See LoopBodyTraits for one
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// example.
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template<class GraphType>
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struct GraphTraits {
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// Elements to provide:
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// typedef NodeRef - Type of Node token in the graph, which should
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// be cheap to copy.
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// typedef ChildIteratorType - Type used to iterate over children in graph,
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// dereference to a NodeRef.
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// static NodeRef getEntryNode(const GraphType &)
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// Return the entry node of the graph
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// static ChildIteratorType child_begin(NodeRef)
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// static ChildIteratorType child_end (NodeRef)
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// Return iterators that point to the beginning and ending of the child
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// node list for the specified node.
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// typedef ...iterator nodes_iterator; - dereference to a NodeRef
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// static nodes_iterator nodes_begin(GraphType *G)
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// static nodes_iterator nodes_end (GraphType *G)
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// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
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// typedef EdgeRef - Type of Edge token in the graph, which should
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// be cheap to copy.
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// typedef ChildEdgeIteratorType - Type used to iterate over children edges in
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// graph, dereference to a EdgeRef.
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// static ChildEdgeIteratorType child_edge_begin(NodeRef)
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// static ChildEdgeIteratorType child_edge_end(NodeRef)
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// Return iterators that point to the beginning and ending of the
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// edge list for the given callgraph node.
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//
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// static NodeRef edge_dest(EdgeRef)
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// Return the destination node of an edge.
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// static unsigned size (GraphType *G)
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// Return total number of nodes in the graph
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// Optionally implement the following:
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// static unsigned getNumber(NodeRef)
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// Return a unique number of a node. Numbers are ideally dense, these are
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// used to store nodes in a vector.
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// static unsigned getMaxNumber(GraphType *G)
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// Return the maximum number that getNumber() will return, or 0 if this is
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// unknown. Intended for reserving large enough buffers.
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// static unsigned getNumberEpoch(GraphType *G)
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// Return the "epoch" of the node numbers. Should return a different
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// number after renumbering, so users can assert that the epoch didn't
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// change => numbers are still valid. If renumberings are not tracked, it
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// is always valid to return a constant value. This is solely for to ease
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// debugging by having a way to detect use of outdated numbers.
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// If anyone tries to use this class without having an appropriate
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// specialization, make an error. If you get this error, it's because you
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// need to include the appropriate specialization of GraphTraits<> for your
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// graph, or you need to define it for a new graph type. Either that or
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// your argument to XXX_begin(...) is unknown or needs to have the proper .h
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// file #include'd.
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using NodeRef = typename GraphType::UnknownGraphTypeError;
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};
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namespace detail {
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template <typename T>
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using has_number_t = decltype(GraphTraits<T>::getNumber(
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std::declval<typename GraphTraits<T>::NodeRef>()));
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} // namespace detail
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/// Indicate whether a GraphTraits<NodeT>::getNumber() is supported.
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template <typename NodeT>
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constexpr bool GraphHasNodeNumbers =
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is_detected<detail::has_number_t, NodeT>::value;
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// Inverse - This class is used as a little marker class to tell the graph
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// iterator to iterate over the graph in a graph defined "Inverse" ordering.
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// Not all graphs define an inverse ordering, and if they do, it depends on
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// the graph exactly what that is. Here's an example of usage with the
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// df_iterator:
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//
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// idf_iterator<Method*> I = idf_begin(M), E = idf_end(M);
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// for (; I != E; ++I) { ... }
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//
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// Which is equivalent to:
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// df_iterator<Inverse<Method*>> I = idf_begin(M), E = idf_end(M);
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// for (; I != E; ++I) { ... }
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//
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template <class GraphType>
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struct Inverse {
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const GraphType &Graph;
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inline Inverse(const GraphType &G) : Graph(G) {}
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};
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// Provide a partial specialization of GraphTraits so that the inverse of an
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// inverse falls back to the original graph.
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template <class T> struct GraphTraits<Inverse<Inverse<T>>> : GraphTraits<T> {};
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// Provide iterator ranges for the graph traits nodes and children
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template <class GraphType>
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iterator_range<typename GraphTraits<GraphType>::nodes_iterator>
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nodes(const GraphType &G) {
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return make_range(GraphTraits<GraphType>::nodes_begin(G),
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GraphTraits<GraphType>::nodes_end(G));
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}
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template <class GraphType>
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iterator_range<typename GraphTraits<Inverse<GraphType>>::nodes_iterator>
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inverse_nodes(const GraphType &G) {
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return make_range(GraphTraits<Inverse<GraphType>>::nodes_begin(G),
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GraphTraits<Inverse<GraphType>>::nodes_end(G));
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}
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template <class GraphType>
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iterator_range<typename GraphTraits<GraphType>::ChildIteratorType>
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children(const typename GraphTraits<GraphType>::NodeRef &G) {
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return make_range(GraphTraits<GraphType>::child_begin(G),
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GraphTraits<GraphType>::child_end(G));
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}
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template <class GraphType>
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iterator_range<typename GraphTraits<Inverse<GraphType>>::ChildIteratorType>
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inverse_children(const typename GraphTraits<GraphType>::NodeRef &G) {
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return make_range(GraphTraits<Inverse<GraphType>>::child_begin(G),
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GraphTraits<Inverse<GraphType>>::child_end(G));
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}
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template <class GraphType>
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iterator_range<typename GraphTraits<GraphType>::ChildEdgeIteratorType>
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children_edges(const typename GraphTraits<GraphType>::NodeRef &G) {
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return make_range(GraphTraits<GraphType>::child_edge_begin(G),
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GraphTraits<GraphType>::child_edge_end(G));
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}
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} // end namespace llvm
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#endif // LLVM_ADT_GRAPHTRAITS_H
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