New files due to the Intervals.h splitup

llvm-svn: 65

2 files changed, 346 insertions, 0 deletions

diff --git a/llvm/include/llvm/Analysis/IntervalIterator.h b/llvm/include/llvm/Analysis/IntervalIterator.h
new file mode 100644
index 00000000000..ec70c8782df
--- /dev/null
+++ b/llvm/include/llvm/Analysis/IntervalIterator.h
@@ -0,0 +1,223 @@
+//===- IntervalIterator.h - Interval Iterator Declaration --------*- C++ -*--=//
+//
+// This file defines an iterator that enumerates the intervals in a control flow
+// graph of some sort.  This iterator is parametric, allowing iterator over the
+// following types of graphs:
+// 
+//  TODO
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_INTERVAL_ITERATOR_H
+#define LLVM_INTERVAL_ITERATOR_H
+
+#include "llvm/Analysis/IntervalPartition.h"
+#include "llvm/Method.h"
+#include "llvm/CFG.h"
+#include <stack>
+#include <set>
+#include <algorithm>
+
+namespace cfg {
+
+// 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*.
+//
+
+
+// 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));
+}
+
+
+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!");
+    }
+  }
+
+  IntervalIterator(IntervalPartition &IP) {
+    OrigContainer = &IP;
+    if (!ProcessInterval(IP.getRootInterval())) {
+      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));
+    }
+  }
+};
+
+typedef IntervalIterator<BasicBlock, Method> method_interval_iterator;
+typedef IntervalIterator<Interval, IntervalPartition> interval_part_interval_iterator;
+
+
+inline method_interval_iterator intervals_begin(Method *M) {
+  return method_interval_iterator(M);
+}
+inline method_interval_iterator intervals_end(Method *M) {
+  return method_interval_iterator();
+}
+
+inline interval_part_interval_iterator intervals_begin(IntervalPartition &IP) {
+  return interval_part_interval_iterator(IP);
+}
+
+inline interval_part_interval_iterator intervals_end(IntervalPartition &IP) {
+  return interval_part_interval_iterator();
+}
+
+}    // End namespace cfg
+
+#endif
diff --git a/llvm/include/llvm/Analysis/IntervalPartition.h b/llvm/include/llvm/Analysis/IntervalPartition.h
new file mode 100644
index 00000000000..fd24b2fb987
--- /dev/null
+++ b/llvm/include/llvm/Analysis/IntervalPartition.h
@@ -0,0 +1,123 @@
+//===- IntervalPartition.h - Interval partition Calculation ------*- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_INTERVAL_PARTITION_H
+#define LLVM_INTERVAL_PARTITION_H
+
+#include "llvm/Analysis/Interval.h"
+#include <map>
+
+class Method;
+
+namespace cfg {
+
+//===----------------------------------------------------------------------===//
+//
+// 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);
+};
+
+}    // End namespace cfg
+
+#endif