-//===- Support/DepthFirstIterator.h - Depth First iterator -------*- C++ -*--=//
+//===- llvm/ADT/DepthFirstIterator.h - Depth First iterator -----*- C++ -*-===//
//
-// This file builds on the Support/GraphTraits.h file to build generic depth
-// first graph iterator.
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file builds on the ADT/GraphTraits.h file to build generic depth
+// first graph iterator. This file exposes the following functions/types:
+//
+// df_begin/df_end/df_iterator
+// * Normal depth-first iteration - visit a node and then all of its children.
+//
+// idf_begin/idf_end/idf_iterator
+// * Depth-first iteration on the 'inverse' graph.
+//
+// df_ext_begin/df_ext_end/df_ext_iterator
+// * Normal depth-first iteration - visit a node and then all of its children.
+// This iterator stores the 'visited' set in an external set, which allows
+// it to be more efficient, and allows external clients to use the set for
+// other purposes.
+//
+// idf_ext_begin/idf_ext_end/idf_ext_iterator
+// * Depth-first iteration on the 'inverse' graph.
+// This iterator stores the 'visited' set in an external set, which allows
+// it to be more efficient, and allows external clients to use the set for
+// other purposes.
//
//===----------------------------------------------------------------------===//
-#ifndef SUPPORT_DEPTHFIRSTITERATOR_H
-#define SUPPORT_DEPTHFIRSTITERATOR_H
+#ifndef LLVM_ADT_DEPTHFIRSTITERATOR_H
+#define LLVM_ADT_DEPTHFIRSTITERATOR_H
-#include "Support/GraphTraits.h"
-#include "Support/iterator"
-#include <stack>
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/PointerIntPair.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/iterator_range.h"
#include <set>
+#include <vector>
+
+namespace llvm {
+
+// df_iterator_storage - A private class which is used to figure out where to
+// store the visited set.
+template<class SetType, bool External> // Non-external set
+class df_iterator_storage {
+public:
+ SetType Visited;
+};
+
+template<class SetType>
+class df_iterator_storage<SetType, true> {
+public:
+ df_iterator_storage(SetType &VSet) : Visited(VSet) {}
+ df_iterator_storage(const df_iterator_storage &S) : Visited(S.Visited) {}
+ SetType &Visited;
+};
// Generic Depth First Iterator
-template<class GraphT, class GT = GraphTraits<GraphT> >
-class df_iterator : public forward_iterator<typename GT::NodeType, ptrdiff_t> {
- typedef forward_iterator<typename GT::NodeType, ptrdiff_t> super;
+template<class GraphT,
+class SetType = llvm::SmallPtrSet<typename GraphTraits<GraphT>::NodeType*, 8>,
+ bool ExtStorage = false, class GT = GraphTraits<GraphT> >
+class df_iterator : public std::iterator<std::forward_iterator_tag,
+ typename GT::NodeType, ptrdiff_t>,
+ public df_iterator_storage<SetType, ExtStorage> {
+ typedef std::iterator<std::forward_iterator_tag,
+ typename GT::NodeType, ptrdiff_t> super;
typedef typename GT::NodeType NodeType;
typedef typename GT::ChildIteratorType ChildItTy;
+ typedef PointerIntPair<NodeType*, 1> PointerIntTy;
- std::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
- std::stack<std::pair<NodeType *, ChildItTy> > VisitStack;
- const bool Reverse; // Iterate over children before self?
+ // if the int in PointerIntTy is 0, the 'next child' to visit is invalid
+ std::vector<std::pair<PointerIntTy, ChildItTy>> VisitStack;
+
private:
- void reverseEnterNode() {
- std::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(std::make_pair(Child, GT::child_begin(Child)));
- reverseEnterNode();
- return;
- }
+ inline df_iterator(NodeType *Node) {
+ this->Visited.insert(Node);
+ VisitStack.push_back(
+ std::make_pair(PointerIntTy(Node, 0), GT::child_begin(Node)));
+ }
+ inline df_iterator() {
+ // End is when stack is empty
+ }
+ inline df_iterator(NodeType *Node, SetType &S)
+ : df_iterator_storage<SetType, ExtStorage>(S) {
+ if (!S.count(Node)) {
+ VisitStack.push_back(
+ std::make_pair(PointerIntTy(Node, 0), GT::child_begin(Node)));
+ this->Visited.insert(Node);
}
}
+ inline df_iterator(SetType &S)
+ : df_iterator_storage<SetType, ExtStorage>(S) {
+ // End is when stack is empty
+ }
+
+ inline void toNext() {
+ do {
+ std::pair<PointerIntTy, ChildItTy> &Top = VisitStack.back();
+ NodeType *Node = Top.first.getPointer();
+ ChildItTy &It = Top.second;
+ if (!Top.first.getInt()) {
+ // now retrieve the real begin of the children before we dive in
+ It = GT::child_begin(Node);
+ Top.first.setInt(1);
+ }
- inline df_iterator(NodeType *Node, bool reverse) : Reverse(reverse) {
- Visited.insert(Node);
- VisitStack.push(std::make_pair(Node, GT::child_begin(Node)));
- if (Reverse) reverseEnterNode();
+ while (It != GT::child_end(Node)) {
+ NodeType *Next = *It++;
+ // Has our next sibling been visited?
+ if (Next && this->Visited.insert(Next).second) {
+ // No, do it now.
+ VisitStack.push_back(
+ std::make_pair(PointerIntTy(Next, 0), GT::child_begin(Next)));
+ return;
+ }
+ }
+
+ // Oops, ran out of successors... go up a level on the stack.
+ VisitStack.pop_back();
+ } while (!VisitStack.empty());
}
- inline df_iterator() { /* End is when stack is empty */ }
public:
typedef typename super::pointer pointer;
- 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 df_iterator begin(const GraphT &G) {
+ return df_iterator(GT::getEntryNode(G));
}
- static inline _Self end(GraphT G) { return _Self(); }
+ static df_iterator end(const GraphT &G) { return df_iterator(); }
+ // Static begin and end methods as our public ctors for external iterators
+ static df_iterator begin(const GraphT &G, SetType &S) {
+ return df_iterator(GT::getEntryNode(G), S);
+ }
+ static df_iterator end(const GraphT &G, SetType &S) { return df_iterator(S); }
- inline bool operator==(const _Self& x) const {
+ bool operator==(const df_iterator &x) const {
return VisitStack == x.VisitStack;
}
- inline bool operator!=(const _Self& x) const { return !operator==(x); }
+ bool operator!=(const df_iterator &x) const { return !(*this == x); }
- inline pointer operator*() const {
- return VisitStack.top().first;
- }
+ pointer operator*() const { return VisitStack.back().first.getPointer(); }
// 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 {
- std::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(std::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;
+ NodeType *operator->() const { return **this; }
+
+ df_iterator &operator++() { // Preincrement
+ toNext();
+ return *this;
+ }
+
+ /// \brief Skips all children of the current node and traverses to next node
+ ///
+ /// Note: This function takes care of incrementing the iterator. If you
+ /// always increment and call this function, you risk walking off the end.
+ df_iterator &skipChildren() {
+ VisitStack.pop_back();
+ if (!VisitStack.empty())
+ toNext();
+ return *this;
}
- inline _Self operator++(int) { // Postincrement
- _Self tmp = *this; ++*this; return tmp;
+ df_iterator operator++(int) { // Postincrement
+ df_iterator 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;
+ bool nodeVisited(NodeType *Node) const {
+ return this->Visited.count(Node) != 0;
}
-};
+ /// getPathLength - Return the length of the path from the entry node to the
+ /// current node, counting both nodes.
+ unsigned getPathLength() const { return VisitStack.size(); }
+
+ /// getPath - Return the n'th node in the path from the entry node to the
+ /// current node.
+ NodeType *getPath(unsigned n) const {
+ return VisitStack[n].first.getPointer();
+ }
+};
// 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);
+df_iterator<T> df_begin(const T& G) {
+ return df_iterator<T>::begin(G);
}
template <class T>
-df_iterator<T> df_end(T G) {
+df_iterator<T> df_end(const T& G) {
return df_iterator<T>::end(G);
}
-// Provide global definitions of inverse depth first iterators...
+// Provide an accessor method to use them in range-based patterns.
template <class T>
-struct idf_iterator : public df_iterator<Inverse<T> > {
- idf_iterator(const df_iterator<Inverse<T> > &V) :df_iterator<Inverse<T> >(V){}
+iterator_range<df_iterator<T>> depth_first(const T& G) {
+ return make_range(df_begin(G), df_end(G));
+}
+
+// Provide global definitions of external depth first iterators...
+template <class T, class SetTy = std::set<typename GraphTraits<T>::NodeType*> >
+struct df_ext_iterator : public df_iterator<T, SetTy, true> {
+ df_ext_iterator(const df_iterator<T, SetTy, true> &V)
+ : df_iterator<T, SetTy, true>(V) {}
+};
+
+template <class T, class SetTy>
+df_ext_iterator<T, SetTy> df_ext_begin(const T& G, SetTy &S) {
+ return df_ext_iterator<T, SetTy>::begin(G, S);
+}
+
+template <class T, class SetTy>
+df_ext_iterator<T, SetTy> df_ext_end(const T& G, SetTy &S) {
+ return df_ext_iterator<T, SetTy>::end(G, S);
+}
+
+template <class T, class SetTy>
+iterator_range<df_ext_iterator<T, SetTy>> depth_first_ext(const T& G,
+ SetTy &S) {
+ return make_range(df_ext_begin(G, S), df_ext_end(G, S));
+}
+
+// Provide global definitions of inverse depth first iterators...
+template <class T,
+ class SetTy = llvm::SmallPtrSet<typename GraphTraits<T>::NodeType*, 8>,
+ bool External = false>
+struct idf_iterator : public df_iterator<Inverse<T>, SetTy, External> {
+ idf_iterator(const df_iterator<Inverse<T>, SetTy, External> &V)
+ : df_iterator<Inverse<T>, SetTy, External>(V) {}
};
template <class T>
-idf_iterator<T> idf_begin(T G, bool Reverse = false) {
- return idf_iterator<T>::begin(G, Reverse);
+idf_iterator<T> idf_begin(const T& G) {
+ return idf_iterator<T>::begin(Inverse<T>(G));
}
template <class T>
-idf_iterator<T> idf_end(T G){
- return idf_iterator<T>::end(G);
+idf_iterator<T> idf_end(const T& G){
+ return idf_iterator<T>::end(Inverse<T>(G));
+}
+
+// Provide an accessor method to use them in range-based patterns.
+template <class T>
+iterator_range<idf_iterator<T>> inverse_depth_first(const T& G) {
+ return make_range(idf_begin(G), idf_end(G));
+}
+
+// Provide global definitions of external inverse depth first iterators...
+template <class T, class SetTy = std::set<typename GraphTraits<T>::NodeType*> >
+struct idf_ext_iterator : public idf_iterator<T, SetTy, true> {
+ idf_ext_iterator(const idf_iterator<T, SetTy, true> &V)
+ : idf_iterator<T, SetTy, true>(V) {}
+ idf_ext_iterator(const df_iterator<Inverse<T>, SetTy, true> &V)
+ : idf_iterator<T, SetTy, true>(V) {}
+};
+
+template <class T, class SetTy>
+idf_ext_iterator<T, SetTy> idf_ext_begin(const T& G, SetTy &S) {
+ return idf_ext_iterator<T, SetTy>::begin(Inverse<T>(G), S);
+}
+
+template <class T, class SetTy>
+idf_ext_iterator<T, SetTy> idf_ext_end(const T& G, SetTy &S) {
+ return idf_ext_iterator<T, SetTy>::end(Inverse<T>(G), S);
}
+template <class T, class SetTy>
+iterator_range<idf_ext_iterator<T, SetTy>> inverse_depth_first_ext(const T& G,
+ SetTy &S) {
+ return make_range(idf_ext_begin(G, S), idf_ext_end(G, S));
+}
+
+} // End llvm namespace
+
#endif
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