Import LLVM, at r72732.

1 files changed, 258 insertions, 0 deletions

diff --git a/include/llvm/Analysis/IntervalIterator.h b/include/llvm/Analysis/IntervalIterator.h
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+//===- IntervalIterator.h - Interval Iterator Declaration -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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:
+//
+//  1. A Function* object, composed of BasicBlock nodes.
+//  2. An IntervalPartition& object, composed of Interval nodes.
+//
+// This iterator is defined to walk the control flow graph, returning intervals
+// in depth first order.  These intervals are completely filled in except for
+// the predecessor fields (the successor information is filled in however).
+//
+// By default, the intervals created by this iterator are deleted after they
+// are no longer any use to the iterator.  This behavior can be changed by
+// passing a false value into the intervals_begin() function. This causes the
+// IOwnMem member to be set, and the intervals to not be deleted.
+//
+// It is only safe to use this if all of the intervals are deleted by the caller
+// and all of the intervals are processed.  However, the user of the iterator is
+// not allowed to modify or delete the intervals until after the iterator has
+// been used completely.  The IntervalPartition class uses this functionality.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_INTERVAL_ITERATOR_H
+#define LLVM_INTERVAL_ITERATOR_H
+
+#include "llvm/Analysis/IntervalPartition.h"
+#include "llvm/Function.h"
+#include "llvm/Support/CFG.h"
+#include <stack>
+#include <set>
+#include <algorithm>
+
+namespace llvm {
+
+// 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(Function *, 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 GT = GraphTraits<NodeTy*>,
+         class IGT = GraphTraits<Inverse<NodeTy*> > >
+class IntervalIterator {
+  std::stack<std::pair<Interval*, typename Interval::succ_iterator> > IntStack;
+  std::set<BasicBlock*> Visited;
+  OrigContainer_t *OrigContainer;
+  bool IOwnMem;     // If True, delete intervals when done with them
+                    // See file header for conditions of use
+public:
+  typedef IntervalIterator<NodeTy, OrigContainer_t> _Self;
+  typedef std::forward_iterator_tag iterator_category;
+
+  IntervalIterator() {} // End iterator, empty stack
+  IntervalIterator(Function *M, bool OwnMemory) : IOwnMem(OwnMemory) {
+    OrigContainer = M;
+    if (!ProcessInterval(&M->front())) {
+      assert(0 && "ProcessInterval should never fail for first interval!");
+    }
+  }
+
+  IntervalIterator(IntervalPartition &IP, bool OwnMemory) : IOwnMem(OwnMemory) {
+    OrigContainer = &IP;
+    if (!ProcessInterval(IP.getRootInterval())) {
+      assert(0 && "ProcessInterval should never fail for first interval!");
+    }
+  }
+
+  inline ~IntervalIterator() {
+    if (IOwnMem)
+      while (!IntStack.empty()) {
+        delete operator*();
+        IntStack.pop();
+      }
+  }
+
+  inline bool operator==(const _Self& x) const { return IntStack == x.IntStack;}
+  inline bool operator!=(const _Self& x) const { return !operator==(x); }
+
+  inline const Interval *operator*() const { return IntStack.top().first; }
+  inline       Interval *operator*()       { return IntStack.top().first; }
+  inline const Interval *operator->() const { return operator*(); }
+  inline       Interval *operator->()       { return operator*(); }
+
+  _Self& operator++() {  // Preincrement
+    assert(!IntStack.empty() && "Attempting to use interval iterator at end!");
+    do {
+      // All of the intervals on the stack have been visited.  Try visiting
+      // their successors now.
+      Interval::succ_iterator &SuccIt = IntStack.top().second,
+                                EndIt = succ_end(IntStack.top().first);
+      while (SuccIt != EndIt) {                 // Loop over all interval succs
+        bool Done = ProcessInterval(getSourceGraphNode(OrigContainer, *SuccIt));
+        ++SuccIt;                               // Increment iterator
+        if (Done) return *this;                 // Found a new interval! Use it!
+      }
+
+      // Free interval memory... if necessary
+      if (IOwnMem) delete IntStack.top().first;
+
+      // 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 = new Interval(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 GT::ChildIteratorType I = GT::child_begin(Node),
+           E = GT::child_end(Node); I != E; ++I)
+      ProcessNode(Int, getSourceGraphNode(OrigContainer, *I));
+
+    IntStack.push(std::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 other 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 IGT::ChildIteratorType I = IGT::child_begin(Node),
+             E = IGT::child_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(std::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 GT::ChildIteratorType It = GT::child_begin(Node),
+             End = GT::child_end(Node); It != End; ++It)
+        ProcessNode(Int, getSourceGraphNode(OrigContainer, *It));
+    }
+  }
+};
+
+typedef IntervalIterator<BasicBlock, Function> function_interval_iterator;
+typedef IntervalIterator<Interval, IntervalPartition> interval_part_interval_iterator;
+
+
+inline function_interval_iterator intervals_begin(Function *F,
+                                                  bool DeleteInts = true) {
+  return function_interval_iterator(F, DeleteInts);
+}
+inline function_interval_iterator intervals_end(Function *) {
+  return function_interval_iterator();
+}
+
+inline interval_part_interval_iterator
+   intervals_begin(IntervalPartition &IP, bool DeleteIntervals = true) {
+  return interval_part_interval_iterator(IP, DeleteIntervals);
+}
+
+inline interval_part_interval_iterator intervals_end(IntervalPartition &IP) {
+  return interval_part_interval_iterator();
+}
+
+} // End llvm namespace
+
+#endif