/3rd_party/llvm/lib/Analysis/IntervalPartition.cpp

  1//===- IntervalPartition.cpp - Interval Partition module code -------------===//
  2//
  3//                     The LLVM Compiler Infrastructure
  4//
  5// This file is distributed under the University of Illinois Open Source
  6// License. See LICENSE.TXT for details.
  7//
  8//===----------------------------------------------------------------------===//
  9//
 10// This file contains the definition of the IntervalPartition class, which
 11// calculates and represent the interval partition of a function.
 12//
 13//===----------------------------------------------------------------------===//
 14
 15#include "llvm/Analysis/IntervalIterator.h"
 16using namespace llvm;
 17
 18char IntervalPartition::ID = 0;
 19INITIALIZE_PASS(IntervalPartition, "intervals",
 20                "Interval Partition Construction", true, true)
 21
 22//===----------------------------------------------------------------------===//
 23// IntervalPartition Implementation
 24//===----------------------------------------------------------------------===//
 25
 26// releaseMemory - Reset state back to before function was analyzed
 27void IntervalPartition::releaseMemory() {
 28  for (unsigned i = 0, e = Intervals.size(); i != e; ++i)
 29    delete Intervals[i];
 30  IntervalMap.clear();
 31  Intervals.clear();
 32  RootInterval = 0;
 33}
 34
 35void IntervalPartition::print(raw_ostream &O, const Module*) const {
 36  for(unsigned i = 0, e = Intervals.size(); i != e; ++i)
 37    Intervals[i]->print(O);
 38}
 39
 40// addIntervalToPartition - Add an interval to the internal list of intervals,
 41// and then add mappings from all of the basic blocks in the interval to the
 42// interval itself (in the IntervalMap).
 43//
 44void IntervalPartition::addIntervalToPartition(Interval *I) {
 45  Intervals.push_back(I);
 46
 47  // Add mappings for all of the basic blocks in I to the IntervalPartition
 48  for (Interval::node_iterator It = I->Nodes.begin(), End = I->Nodes.end();
 49       It != End; ++It)
 50    IntervalMap.insert(std::make_pair(*It, I));
 51}
 52
 53// updatePredecessors - Interval generation only sets the successor fields of
 54// the interval data structures.  After interval generation is complete,
 55// run through all of the intervals and propagate successor info as
 56// predecessor info.
 57//
 58void IntervalPartition::updatePredecessors(Interval *Int) {
 59  BasicBlock *Header = Int->getHeaderNode();
 60  for (Interval::succ_iterator I = Int->Successors.begin(),
 61         E = Int->Successors.end(); I != E; ++I)
 62    getBlockInterval(*I)->Predecessors.push_back(Header);
 63}
 64
 65// IntervalPartition ctor - Build the first level interval partition for the
 66// specified function...
 67//
 68bool IntervalPartition::runOnFunction(Function &F) {
 69  // Pass false to intervals_begin because we take ownership of it's memory
 70  function_interval_iterator I = intervals_begin(&F, false);
 71  assert(I != intervals_end(&F) && "No intervals in function!?!?!");
 72
 73  addIntervalToPartition(RootInterval = *I);
 74
 75  ++I;  // After the first one...
 76
 77  // Add the rest of the intervals to the partition.
 78  for (function_interval_iterator E = intervals_end(&F); I != E; ++I)
 79    addIntervalToPartition(*I);
 80
 81  // Now that we know all of the successor information, propagate this to the
 82  // predecessors for each block.
 83  for (unsigned i = 0, e = Intervals.size(); i != e; ++i)
 84    updatePredecessors(Intervals[i]);
 85  return false;
 86}
 87
 88
 89// IntervalPartition ctor - Build a reduced interval partition from an
 90// existing interval graph.  This takes an additional boolean parameter to
 91// distinguish it from a copy constructor.  Always pass in false for now.
 92//
 93IntervalPartition::IntervalPartition(IntervalPartition &IP, bool)
 94  : FunctionPass(ID) {
 95  assert(IP.getRootInterval() && "Cannot operate on empty IntervalPartitions!");
 96
 97  // Pass false to intervals_begin because we take ownership of it's memory
 98  interval_part_interval_iterator I = intervals_begin(IP, false);
 99  assert(I != intervals_end(IP) && "No intervals in interval partition!?!?!");
100
101  addIntervalToPartition(RootInterval = *I);
102
103  ++I;  // After the first one...
104
105  // Add the rest of the intervals to the partition.
106  for (interval_part_interval_iterator E = intervals_end(IP); I != E; ++I)
107    addIntervalToPartition(*I);
108
109  // Now that we know all of the successor information, propagate this to the
110  // predecessors for each block.
111  for (unsigned i = 0, e = Intervals.size(); i != e; ++i)
112    updatePredecessors(Intervals[i]);
113}
114