[llvm] r195783 - [PM] [cleanup] Update doxygen comments to use the new style, add some
Chandler Carruth
chandlerc at gmail.com
Tue Nov 26 12:51:48 PST 2013
Author: chandlerc
Date: Tue Nov 26 14:51:48 2013
New Revision: 195783
URL: http://llvm.org/viewvc/llvm-project?rev=195783&view=rev
Log:
[PM] [cleanup] Update doxygen comments to use the new style, add some
doxygen comments, make existing comments doxygen comments etc.
Also, switch commented-out debug helpers to #if-0-ed out debug helpers.
No functionality changed.
Modified:
llvm/trunk/include/llvm/ADT/SCCIterator.h
Modified: llvm/trunk/include/llvm/ADT/SCCIterator.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/SCCIterator.h?rev=195783&r1=195782&r2=195783&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/SCCIterator.h (original)
+++ llvm/trunk/include/llvm/ADT/SCCIterator.h Tue Nov 26 14:51:48 2013
@@ -6,16 +6,18 @@
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
-//
-// This builds on the llvm/ADT/GraphTraits.h file to find the strongly connected
-// components (SCCs) of a graph in O(N+E) time using Tarjan's DFS algorithm.
-//
-// The SCC iterator has the important property that if a node in SCC S1 has an
-// edge to a node in SCC S2, then it visits S1 *after* S2.
-//
-// To visit S1 *before* S2, use the scc_iterator on the Inverse graph.
-// (NOTE: This requires some simple wrappers and is not supported yet.)
-//
+/// \file
+///
+/// This builds on the llvm/ADT/GraphTraits.h file to find the strongly
+/// connected components (SCCs) of a graph in O(N+E) time using Tarjan's DFS
+/// algorithm.
+///
+/// The SCC iterator has the important property that if a node in SCC S1 has an
+/// edge to a node in SCC S2, then it visits S1 *after* S2.
+///
+/// To visit S1 *before* S2, use the scc_iterator on the Inverse graph. (NOTE:
+/// This requires some simple wrappers and is not supported yet.)
+///
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_SCCITERATOR_H
@@ -27,11 +29,12 @@
namespace llvm {
-//===----------------------------------------------------------------------===//
-///
-/// scc_iterator - Enumerate the SCCs of a directed graph, in
-/// reverse topological order of the SCC DAG.
+/// \brief Enumerate the SCCs of a directed graph in reverse topological order
+/// of the SCC DAG.
///
+/// This is implemented using Tarjan's DFS algorithm using an internal stack to
+/// build up a vector of nodes in a particular SCC. Note that it is a forward
+/// iterator and thus you cannot backtrack or re-visit nodes.
template<class GraphT, class GT = GraphTraits<GraphT> >
class scc_iterator
: public std::iterator<std::forward_iterator_tag,
@@ -50,30 +53,32 @@ class scc_iterator
unsigned visitNum;
DenseMap<NodeType *, unsigned> nodeVisitNumbers;
- // SCCNodeStack - Stack holding nodes of the SCC.
+ // Stack holding nodes of the SCC.
std::vector<NodeType *> SCCNodeStack;
- // CurrentSCC - The current SCC, retrieved using operator*().
+ // The current SCC, retrieved using operator*().
SccTy CurrentSCC;
- // VisitStack - Used to maintain the ordering. Top = current block
- // First element is basic block pointer, second is the 'next child' to visit
+ // Used to maintain the ordering. The top is the current block, the first
+ // element is basic block pointer, second is the 'next child' to visit.
std::vector<std::pair<NodeType *, ChildItTy> > VisitStack;
- // MinVisitNumStack - Stack holding the "min" values for each node in the DFS.
- // This is used to track the minimum uplink values for all children of
- // the corresponding node on the VisitStack.
+ // Stack holding the "min" values for each node in the DFS. This is used to
+ // track the minimum uplink values for all children of the corresponding node
+ // on the VisitStack.
std::vector<unsigned> MinVisitNumStack;
// A single "visit" within the non-recursive DFS traversal.
void DFSVisitOne(NodeType *N) {
- ++visitNum; // Global counter for the visit order
+ ++visitNum;
nodeVisitNumbers[N] = visitNum;
SCCNodeStack.push_back(N);
MinVisitNumStack.push_back(visitNum);
VisitStack.push_back(std::make_pair(N, GT::child_begin(N)));
- //dbgs() << "TarjanSCC: Node " << N <<
- // " : visitNum = " << visitNum << "\n";
+#if 0 // Enable if needed when debugging.
+ dbgs() << "TarjanSCC: Node " << N <<
+ " : visitNum = " << visitNum << "\n";
+#endif
}
// The stack-based DFS traversal; defined below.
@@ -108,9 +113,11 @@ class scc_iterator
if (!MinVisitNumStack.empty() && MinVisitNumStack.back() > minVisitNum)
MinVisitNumStack.back() = minVisitNum;
- //dbgs() << "TarjanSCC: Popped node " << visitingN <<
- // " : minVisitNum = " << minVisitNum << "; Node visit num = " <<
- // nodeVisitNumbers[visitingN] << "\n";
+#if 0 // Enable if needed when debugging.
+ dbgs() << "TarjanSCC: Popped node " << visitingN <<
+ " : minVisitNum = " << minVisitNum << "; Node visit num = " <<
+ nodeVisitNumbers[visitingN] << "\n";
+#endif
if (minVisitNum != nodeVisitNumbers[visitingN])
continue;
@@ -137,11 +144,11 @@ class scc_iterator
public:
typedef scc_iterator<GraphT, GT> _Self;
- // Provide static "constructors"...
static inline _Self begin(const GraphT &G){return _Self(GT::getEntryNode(G));}
static inline _Self end (const GraphT &) { return _Self(); }
- // Direct loop termination test: I.isAtEnd() is more efficient than I == end()
+ /// \brief Direct loop termination test which is more efficient than
+ /// comparison with \c end().
inline bool isAtEnd() const {
assert(!CurrentSCC.empty() || VisitStack.empty());
return CurrentSCC.empty();
@@ -152,16 +159,14 @@ public:
}
inline bool operator!=(const _Self& x) const { return !operator==(x); }
- // Iterator traversal: forward iteration only
- inline _Self& operator++() { // Preincrement
+ inline _Self& operator++() {
GetNextSCC();
return *this;
}
- inline _Self operator++(int) { // Postincrement
+ inline _Self operator++(int) {
_Self tmp = *this; ++*this; return tmp;
}
- // Retrieve a reference to the current SCC
inline const SccTy &operator*() const {
assert(!CurrentSCC.empty() && "Dereferencing END SCC iterator!");
return CurrentSCC;
@@ -171,9 +176,10 @@ public:
return CurrentSCC;
}
- // hasLoop() -- Test if the current SCC has a loop. If it has more than one
- // node, this is trivially true. If not, it may still contain a loop if the
- // node has an edge back to itself.
+ /// \brief Test if the current SCC has a loop.
+ ///
+ /// If the SCC has more than one node, this is trivially true. If not, it may
+ /// still contain a loop if the node has an edge back to itself.
bool hasLoop() const {
assert(!CurrentSCC.empty() && "Dereferencing END SCC iterator!");
if (CurrentSCC.size() > 1) return true;
@@ -184,8 +190,8 @@ public:
return false;
}
- /// ReplaceNode - This informs the scc_iterator that the specified Old node
- /// has been deleted, and New is to be used in its place.
+ /// This informs the \c scc_iterator that the specified \c Old node
+ /// has been deleted, and \c New is to be used in its place.
void ReplaceNode(NodeType *Old, NodeType *New) {
assert(nodeVisitNumbers.count(Old) && "Old not in scc_iterator?");
nodeVisitNumbers[New] = nodeVisitNumbers[Old];
@@ -194,22 +200,25 @@ public:
};
-// Global constructor for the SCC iterator.
+/// \brief Construct the begin iterator for a deduced graph type T.
template <class T>
scc_iterator<T> scc_begin(const T &G) {
return scc_iterator<T>::begin(G);
}
+/// \brief Construct the end iterator for a deduced graph type T.
template <class T>
scc_iterator<T> scc_end(const T &G) {
return scc_iterator<T>::end(G);
}
+/// \brief Construct the begin iterator for a deduced graph type T's Inverse<T>.
template <class T>
scc_iterator<Inverse<T> > scc_begin(const Inverse<T> &G) {
return scc_iterator<Inverse<T> >::begin(G);
}
+/// \brief Construct the end iterator for a deduced graph type T's Inverse<T>.
template <class T>
scc_iterator<Inverse<T> > scc_end(const Inverse<T> &G) {
return scc_iterator<Inverse<T> >::end(G);
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