src/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"
  16 using namespace llvm;
  17
  18 char IntervalPartition::ID = 0;
  19 INITIALIZE_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
  27 void 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 = nullptr;
  33 }
  34
  35 void 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 //
  44 void 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 //
  58 void 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 //
  68 bool 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 //
  93 IntervalPartition::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