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
115