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authorChris Lattner <sabre@nondot.org>2001-11-27 00:03:19 +0000
committerChris Lattner <sabre@nondot.org>2001-11-27 00:03:19 +0000
commitcee8f9ae67104576b2028125b56e9ba4856a1d66 (patch)
treec09d4ff10492acc211b36238768e14ccfd32d750 /include/llvm/ADT/DepthFirstIterator.h
parent360e17eaf1a2abda82b02235dc57d26d8f83c937 (diff)
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Create a new #include "Support/..." directory structure to move things
from "llvm/Support/..." that are not llvm dependant. Move files and fix #includes git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1400 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'include/llvm/ADT/DepthFirstIterator.h')
-rw-r--r--include/llvm/ADT/DepthFirstIterator.h147
1 files changed, 147 insertions, 0 deletions
diff --git a/include/llvm/ADT/DepthFirstIterator.h b/include/llvm/ADT/DepthFirstIterator.h
new file mode 100644
index 0000000..a2d5a9d
--- /dev/null
+++ b/include/llvm/ADT/DepthFirstIterator.h
@@ -0,0 +1,147 @@
+//===- Support/DepthFirstIterator.h - Depth First iterator -------*- C++ -*--=//
+//
+// This file builds on the Support/GraphTraits.h file to build generic depth
+// first graph iterator.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_DEPTH_FIRST_ITERATOR_H
+#define LLVM_SUPPORT_DEPTH_FIRST_ITERATOR_H
+
+#include "Support/GraphTraits.h"
+#include <iterator>
+#include <stack>
+#include <set>
+
+// Generic Depth First Iterator
+template<class GraphT, class GT = GraphTraits<GraphT> >
+class df_iterator : public std::forward_iterator<typename GT::NodeType,
+ ptrdiff_t> {
+ typedef typename GT::NodeType NodeType;
+ typedef typename GT::ChildIteratorType ChildItTy;
+
+ set<NodeType *> Visited; // All of the blocks visited so far...
+ // VisitStack - Used to maintain the ordering. Top = current block
+ // First element is node pointer, second is the 'next child' to visit
+ stack<pair<NodeType *, ChildItTy> > VisitStack;
+ const bool Reverse; // Iterate over children before self?
+private:
+ void reverseEnterNode() {
+ pair<NodeType *, ChildItTy> &Top = VisitStack.top();
+ NodeType *Node = Top.first;
+ ChildItTy &It = Top.second;
+ for (; It != GT::child_end(Node); ++It) {
+ NodeType *Child = *It;
+ if (!Visited.count(Child)) {
+ Visited.insert(Child);
+ VisitStack.push(make_pair(Child, GT::child_begin(Child)));
+ reverseEnterNode();
+ return;
+ }
+ }
+ }
+
+ inline df_iterator(NodeType *Node, bool reverse) : Reverse(reverse) {
+ Visited.insert(Node);
+ VisitStack.push(make_pair(Node, GT::child_begin(Node)));
+ if (Reverse) reverseEnterNode();
+ }
+ inline df_iterator() { /* End is when stack is empty */ }
+
+public:
+ typedef df_iterator<GraphT, GT> _Self;
+
+ // Provide static begin and end methods as our public "constructors"
+ static inline _Self begin(GraphT G, bool Reverse = false) {
+ return _Self(GT::getEntryNode(G), Reverse);
+ }
+ static inline _Self end(GraphT G) { return _Self(); }
+
+
+ inline bool operator==(const _Self& x) const {
+ return VisitStack == x.VisitStack;
+ }
+ inline bool operator!=(const _Self& x) const { return !operator==(x); }
+
+ inline pointer operator*() const {
+ return VisitStack.top().first;
+ }
+
+ // This is a nonstandard operator-> that dereferences the pointer an extra
+ // time... so that you can actually call methods ON the Node, because
+ // the contained type is a pointer. This allows BBIt->getTerminator() f.e.
+ //
+ inline NodeType *operator->() const { return operator*(); }
+
+ inline _Self& operator++() { // Preincrement
+ if (Reverse) { // Reverse Depth First Iterator
+ if (VisitStack.top().second == GT::child_end(VisitStack.top().first))
+ VisitStack.pop();
+ if (!VisitStack.empty())
+ reverseEnterNode();
+ } else { // Normal Depth First Iterator
+ do {
+ pair<NodeType *, ChildItTy> &Top = VisitStack.top();
+ NodeType *Node = Top.first;
+ ChildItTy &It = Top.second;
+
+ while (It != GT::child_end(Node)) {
+ NodeType *Next = *It++;
+ if (!Visited.count(Next)) { // Has our next sibling been visited?
+ // No, do it now.
+ Visited.insert(Next);
+ VisitStack.push(make_pair(Next, GT::child_begin(Next)));
+ return *this;
+ }
+ }
+
+ // Oops, ran out of successors... go up a level on the stack.
+ VisitStack.pop();
+ } while (!VisitStack.empty());
+ }
+ return *this;
+ }
+
+ inline _Self operator++(int) { // Postincrement
+ _Self tmp = *this; ++*this; return tmp;
+ }
+
+ // nodeVisited - return true if this iterator has already visited the
+ // specified node. This is public, and will probably be used to iterate over
+ // nodes that a depth first iteration did not find: ie unreachable nodes.
+ //
+ inline bool nodeVisited(NodeType *Node) const {
+ return Visited.count(Node) != 0;
+ }
+};
+
+
+// Provide global constructors that automatically figure out correct types...
+//
+template <class T>
+df_iterator<T> df_begin(T G, bool Reverse = false) {
+ return df_iterator<T>::begin(G, Reverse);
+}
+
+template <class T>
+df_iterator<T> df_end(T G) {
+ return df_iterator<T>::end(G);
+}
+
+// Provide global definitions of inverse depth first iterators...
+template <class T>
+struct idf_iterator : public df_iterator<Inverse<T> > {
+ idf_iterator(const df_iterator<Inverse<T> > &V) :df_iterator<Inverse<T> >(V){}
+};
+
+template <class T>
+idf_iterator<T> idf_begin(T G, bool Reverse = false) {
+ return idf_iterator<T>::begin(G, Reverse);
+}
+
+template <class T>
+idf_iterator<T> idf_end(T G){
+ return idf_iterator<T>::end(G);
+}
+
+#endif