IntervalPartition & IntervalIterator classes have been split out into

their own .h files


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 24 insertions, 316 deletions

diff --git a/include/llvm/Analysis/Interval.h b/include/llvm/Analysis/Interval.h
index e22e9e251d..33f7d4182c 100644
--- a/include/llvm/Analysis/Interval.h
+++ b/include/llvm/Analysis/Interval.h
@@ -1,36 +1,24 @@
-//===- llvm/Analysis/Intervals.h - Interval partition Calculation-*- C++ -*--=//
+//===- llvm/Analysis/Interval.h - Interval Class Declaration -----*- C++ -*--=//
 //
-// This file contains the declaration of the cfg::IntervalPartition class, which
-// calculates and represents the interval partition of a method, or a
-// preexisting interval partition.
-//
-// In this way, the interval partition may be used to reduce a flow graph down
-// to its degenerate single node interval partition (unless it is irreducible).
-//
-// TODO: The IntervalPartition class should take a bool parameter that tells
-// whether it should add the "tails" of an interval to an interval itself or if
-// they should be represented as distinct intervals.
+// This file contains the declaration of the cfg::Interval class, which
+// represents a set of CFG nodes and is a portion of an interval partition.
+// 
+// Intervals have some interesting and useful properties, including the
+// following:
+//    1. The header node of an interval dominates all of the elements of the
+//       interval
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_INTERVALS_H
-#define LLVM_INTERVALS_H
+#ifndef LLVM_INTERVAL_H
+#define LLVM_INTERVAL_H
 
-#include "llvm/Method.h"
-#include "llvm/CFG.h"
 #include <vector>
-#include <map>
-#include <stack>
-#include <set>
-#include <algorithm>
 
-class Method;
 class BasicBlock;
 
 namespace cfg {
 
-class IntervalPartition;
-
 //===----------------------------------------------------------------------===//
 //
 // Interval Class - An Interval is a set of nodes defined such that every node
@@ -38,8 +26,6 @@ class IntervalPartition;
 // header)
 //
 class Interval {
-  friend class IntervalPartition;
-
   // HeaderNode - The header BasicBlock, which dominates all BasicBlocks in this
   // interval.  Also, any loops in this interval must go through the HeaderNode.
   //
@@ -49,6 +35,10 @@ public:
   typedef vector<BasicBlock*>::iterator pred_iterator;
   typedef vector<BasicBlock*>::iterator node_iterator;
 
+  inline Interval(BasicBlock *Header) : HeaderNode(Header) {
+    Nodes.push_back(Header);
+  }
+
   inline BasicBlock *getHeaderNode() const { return HeaderNode; }
 
   // Nodes - The basic blocks in this interval.
@@ -68,21 +58,24 @@ public:
 
   // contains - Find out if a basic block is in this interval
   inline bool contains(BasicBlock *BB) const {
-    return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
+    for (unsigned i = 0; i < Nodes.size(); ++i)
+      if (Nodes[i] == BB) return true;
+    return false;
+    // I don't want the dependency on <algorithm>
+    //return find(Nodes.begin(), Nodes.end(), BB) != Nodes.end();
   }
 
   // isSuccessor - find out if a basic block is a successor of this Interval
   inline bool isSuccessor(BasicBlock *BB) const {
-    return find(Successors.begin(), Successors.end(), BB) != Successors.end();
+    for (unsigned i = 0; i < Successors.size(); ++i)
+      if (Successors[i] == BB) return true;
+    return false;
+    // I don't want the dependency on <algorithm>
+    //return find(Successors.begin(), Successors.end(), BB) != Successors.end();
   }
 
   // isLoop - Find out if there is a back edge in this interval...
   bool isLoop() const;
-
-  //private:           // Only accessable by IntervalPartition class
-  inline Interval(BasicBlock *Header) : HeaderNode(Header) {
-    Nodes.push_back(Header);
-  }
 };
 
 
@@ -106,291 +99,6 @@ inline Interval::pred_iterator pred_end(Interval *I) {
   return I->Predecessors.end();
 }
 
-
-//===----------------------------------------------------------------------===//
-//                             IntervalIterator
-//
-// TODO: Provide an interval iterator that codifies the internals of 
-// IntervalPartition.  Inside, it would have a stack of Interval*'s, and would
-// walk the interval partition in depth first order.  IntervalPartition would
-// then be a client of this iterator.  The iterator should work on Method*,
-// const Method*, IntervalPartition*, and const IntervalPartition*.
-//
-
-template<class NodeTy, class OrigContainer_t>
-class IntervalIterator {
-  stack<pair<Interval, typename Interval::succ_iterator> > IntStack;
-  set<BasicBlock*> Visited;
-  OrigContainer_t *OrigContainer;
-public:
-  typedef BasicBlock* _BB;
-
-  typedef IntervalIterator<NodeTy, OrigContainer_t> _Self;
-  typedef forward_iterator_tag iterator_category;
- 
-  IntervalIterator() {} // End iterator, empty stack
-  IntervalIterator(Method *M) {
-    OrigContainer = M;
-    if (!ProcessInterval(M->getBasicBlocks().front())) {
-      assert(0 && "ProcessInterval should never fail for first interval!");
-    }
-  }
-
-  inline bool operator==(const _Self& x) const { return IntStack == x.IntStack; }
-  inline bool operator!=(const _Self& x) const { return !operator==(x); }
-
-  inline Interval &operator*() const { return IntStack.top(); }
-  inline Interval *operator->() const { return &(operator*()); }
-
-  inline _Self& operator++() {  // Preincrement
-    do {
-      // All of the intervals on the stack have been visited.  Try visiting their
-      // successors now.
-      Interval           &CurInt = IntStack.top().first;
-      Interval::iterator &SuccIt = IntStack.top().second,End = succ_end(&CurInt);
-
-      for (; SuccIt != End; ++SuccIt)    // Loop over all interval successors
-	if (ProcessInterval(*SuccIt))    // Found a new interval!
-	  return *this;                  // Use it!
-
-      // We ran out of successors for this interval... pop off the stack
-      IntStack.pop();
-    } while (!IntStack.empty());
-
-    return *this; 
-  }
-  inline _Self operator++(int) { // Postincrement
-    _Self tmp = *this; ++*this; return tmp; 
-  }
-
-private:
-  // ProcessInterval - This method is used during the construction of the 
-  // interval graph.  It walks through the source graph, recursively creating
-  // an interval per invokation until the entire graph is covered.  This uses
-  // the ProcessNode method to add all of the nodes to the interval.
-  //
-  // This method is templated because it may operate on two different source
-  // graphs: a basic block graph, or a preexisting interval graph.
-  //
-  bool ProcessInterval(NodeTy *Node) {
-    BasicBlock *Header = getNodeHeader(Node);
-    if (Visited.count(Header)) return false;
-
-    Interval Int(Header);
-    Visited.insert(Header);   // The header has now been visited!
-
-    // Check all of our successors to see if they are in the interval...
-    for (typename NodeTy::succ_iterator I = succ_begin(Node), E = succ_end(Node);
-	 I != E; ++I)
-      ProcessNode(&Int, getSourceGraphNode(OrigContainer, *I));
-
-    IntStack.push(make_pair(Int, succ_begin(&Int)));
-    return true;
-  }
-  
-  // ProcessNode - This method is called by ProcessInterval to add nodes to the
-  // interval being constructed, and it is also called recursively as it walks
-  // the source graph.  A node is added to the current interval only if all of
-  // its predecessors are already in the graph.  This also takes care of keeping
-  // the successor set of an interval up to date.
-  //
-  // This method is templated because it may operate on two different source
-  // graphs: a basic block graph, or a preexisting interval graph.
-  //
-  void ProcessNode(Interval *Int, NodeTy *Node) {
-    assert(Int && "Null interval == bad!");
-    assert(Node && "Null Node == bad!");
-  
-    BasicBlock *NodeHeader = getNodeHeader(Node);
-
-    if (Visited.count(NodeHeader)) {     // Node already been visited?
-      if (Int->contains(NodeHeader)) {   // Already in this interval...
-	return;
-      } else {                           // In another interval, add as successor
-	if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set
-	  Int->Successors.push_back(NodeHeader);
-      }
-    } else {                             // Otherwise, not in interval yet
-      for (typename NodeTy::pred_iterator I = pred_begin(Node), 
-	                                  E = pred_end(Node); I != E; ++I) {
-	if (!Int->contains(*I)) {        // If pred not in interval, we can't be
-	  if (!Int->isSuccessor(NodeHeader)) // Add only if not already in set
-	    Int->Successors.push_back(NodeHeader);
-	  return;                        // See you later
-	}
-      }
-
-      // If we get here, then all of the predecessors of BB are in the interval
-      // already.  In this case, we must add BB to the interval!
-      addNodeToInterval(Int, Node);
-      Visited.insert(NodeHeader);     // The node has now been visited!
-    
-      if (Int->isSuccessor(NodeHeader)) {
-	// If we were in the successor list from before... remove from succ list
-	Int->Successors.erase(remove(Int->Successors.begin(),
-				     Int->Successors.end(), NodeHeader), 
-			      Int->Successors.end());
-      }
-    
-      // Now that we have discovered that Node is in the interval, perhaps some
-      // of its successors are as well?
-      for (typename NodeTy::succ_iterator It = succ_begin(Node), 
-	     End = succ_end(Node); It != End; ++It)
-	ProcessNode(Int, getSourceGraphNode(OrigContainer, *It));
-    }
-  }
-};
-
-
-//===----------------------------------------------------------------------===//
-//
-// IntervalPartition - This class builds and holds an "interval partition" for
-// a method.  This partition divides the control flow graph into a set of
-// maximal intervals, as defined with the properties above.  Intuitively, a
-// BasicBlock is a (possibly nonexistent) loop with a "tail" of non looping
-// nodes following it.
-//
-class IntervalPartition {
-  typedef map<BasicBlock*, Interval*> IntervalMapTy;
-  IntervalMapTy IntervalMap;
-
-  typedef vector<Interval*> IntervalListTy;
-  IntervalListTy IntervalList;
-  Interval *RootInterval;
-
-public:
-  typedef IntervalListTy::iterator iterator;
-
-public:
-  // IntervalPartition ctor - Build the partition for the specified method
-  IntervalPartition(Method *M);
-
-  // IntervalPartition ctor - Build a reduced interval partition from an
-  // existing interval graph.  This takes an additional boolean parameter to
-  // distinguish it from a copy constructor.  Always pass in false for now.
-  //
-  IntervalPartition(IntervalPartition &I, bool);
-
-  // Destructor - Free memory
-  ~IntervalPartition();
-
-  // getRootInterval() - Return the root interval that contains the starting
-  // block of the method.
-  inline Interval *getRootInterval() { return RootInterval; }
-
-  // isDegeneratePartition() - Returns true if the interval partition contains
-  // a single interval, and thus cannot be simplified anymore.
-  bool isDegeneratePartition() { return size() == 1; }
-
-  // TODO: isIrreducible - look for triangle graph.
-
-  // getBlockInterval - Return the interval that a basic block exists in.
-  inline Interval *getBlockInterval(BasicBlock *BB) {
-    IntervalMapTy::iterator I = IntervalMap.find(BB);
-    return I != IntervalMap.end() ? I->second : 0;
-  }
-
-  // Iterators to iterate over all of the intervals in the method
-  inline iterator begin() { return IntervalList.begin(); }
-  inline iterator end()   { return IntervalList.end(); }
-  inline unsigned size()  { return IntervalList.size(); }
-
-private:
-  // ProcessInterval - This method is used during the construction of the 
-  // interval graph.  It walks through the source graph, recursively creating
-  // an interval per invokation until the entire graph is covered.  This uses
-  // the ProcessNode method to add all of the nodes to the interval.
-  //
-  // This method is templated because it may operate on two different source
-  // graphs: a basic block graph, or a preexisting interval graph.
-  //
-  template<class NodeTy, class OrigContainer>
-  void ProcessInterval(NodeTy *Node, OrigContainer *OC);
-
-  // ProcessNode - This method is called by ProcessInterval to add nodes to the
-  // interval being constructed, and it is also called recursively as it walks
-  // the source graph.  A node is added to the current interval only if all of
-  // its predecessors are already in the graph.  This also takes care of keeping
-  // the successor set of an interval up to date.
-  //
-  // This method is templated because it may operate on two different source
-  // graphs: a basic block graph, or a preexisting interval graph.
-  //
-  template<class NodeTy, class OrigContainer>
-  void ProcessNode(Interval *Int, NodeTy *Node, OrigContainer *OC);
-
-  // addNodeToInterval - This method exists to assist the generic ProcessNode
-  // with the task of adding a node to the new interval, depending on the 
-  // type of the source node.  In the case of a CFG source graph (BasicBlock 
-  // case), the BasicBlock itself is added to the interval.  In the case of
-  // an IntervalPartition source graph (Interval case), all of the member
-  // BasicBlocks are added to the interval.
-  //
-  inline void addNodeToInterval(Interval *Int, Interval *I);
-  inline void addNodeToInterval(Interval *Int, BasicBlock *BB);
-
-  // updatePredecessors - Interval generation only sets the successor fields of
-  // the interval data structures.  After interval generation is complete,
-  // run through all of the intervals and propogate successor info as
-  // predecessor info.
-  //
-  void updatePredecessors(Interval *Int);
-};
-
-
-
-// getNodeHeader - Given a source graph node and the source graph, return the 
-// BasicBlock that is the header node.  This is the opposite of
-// getSourceGraphNode.
-//
-inline BasicBlock *getNodeHeader(BasicBlock *BB) { return BB; }
-inline BasicBlock *getNodeHeader(Interval *I) { return I->getHeaderNode(); }
-
-// getSourceGraphNode - Given a BasicBlock and the source graph, return the 
-// source graph node that corresponds to the BasicBlock.  This is the opposite
-// of getNodeHeader.
-//
-inline BasicBlock *getSourceGraphNode(Method *, BasicBlock *BB) {
-  return BB; 
-}
-inline Interval *getSourceGraphNode(IntervalPartition *IP, BasicBlock *BB) { 
-  return IP->getBlockInterval(BB);
-}
-
-// addNodeToInterval - This method exists to assist the generic ProcessNode
-// with the task of adding a node to the new interval, depending on the 
-// type of the source node.  In the case of a CFG source graph (BasicBlock 
-// case), the BasicBlock itself is added to the interval.
-//
-inline void addNodeToInterval(Interval *Int, BasicBlock *BB){
-  Int->Nodes.push_back(BB);
-}
-
-// addNodeToInterval - This method exists to assist the generic ProcessNode
-// with the task of adding a node to the new interval, depending on the 
-// type of the source node.  In the case of a CFG source graph (BasicBlock 
-// case), the BasicBlock itself is added to the interval.  In the case of
-// an IntervalPartition source graph (Interval case), all of the member
-// BasicBlocks are added to the interval.
-//
-inline void addNodeToInterval(Interval *Int, Interval *I) {
-  // Add all of the nodes in I as new nodes in Int.
-  copy(I->Nodes.begin(), I->Nodes.end(), back_inserter(Int->Nodes));
-}
-
-
-
-
-typedef IntervalIterator<BasicBlock, Method> method_interval_iterator;
-
-
-method_interval_iterator intervals_begin(Method *M) {
-  return method_interval_iterator(M);
-}
-method_interval_iterator intervals_end(Method *M) {
-  return method_interval_iterator();
-}
-
 }    // End namespace cfg
 
 #endif