SlotIndexes.cpp revision d6a717cba117dae9a90a373698f691d9452c9c49 
1//===-- SlotIndexes.cpp - Slot Indexes Pass  ------------------------------===//
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#define DEBUG_TYPE "slotindexes"
11
12#include "llvm/CodeGen/SlotIndexes.h"
13#include "llvm/CodeGen/MachineFunction.h"
14#include "llvm/Support/Debug.h"
15#include "llvm/Support/raw_ostream.h"
16
17using namespace llvm;
18
19std::auto_ptr<IndexListEntry> SlotIndex::emptyKeyPtr(0),
20                              SlotIndex::tombstoneKeyPtr(0);
21
22char SlotIndexes::ID = 0;
23static RegisterPass<SlotIndexes> X("slotindexes", "Slot index numbering");
24
25void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const {
26  au.setPreservesAll();
27  MachineFunctionPass::getAnalysisUsage(au);
28}
29
30void SlotIndexes::releaseMemory() {
31  mi2iMap.clear();
32  mbb2IdxMap.clear();
33  idx2MBBMap.clear();
34  terminatorGaps.clear();
35  clearList();
36}
37
38bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
39
40  // Compute numbering as follows:
41  // Grab an iterator to the start of the index list.
42  // Iterate over all MBBs, and within each MBB all MIs, keeping the MI
43  // iterator in lock-step (though skipping it over indexes which have
44  // null pointers in the instruction field).
45  // At each iteration assert that the instruction pointed to in the index
46  // is the same one pointed to by the MI iterator. This
47
48  // FIXME: This can be simplified. The mi2iMap_, Idx2MBBMap, etc. should
49  // only need to be set up once after the first numbering is computed.
50
51  mf = &fn;
52  initList();
53
54  const unsigned gap = 1;
55
56  // Check that the list contains only the sentinal.
57  assert(indexListHead->getNext() == 0 &&
58         "Index list non-empty at initial numbering?");
59  assert(idx2MBBMap.empty() &&
60         "Index -> MBB mapping non-empty at initial numbering?");
61  assert(mbb2IdxMap.empty() &&
62         "MBB -> Index mapping non-empty at initial numbering?");
63  assert(mi2iMap.empty() &&
64         "MachineInstr -> Index mapping non-empty at initial numbering?");
65
66  functionSize = 0;
67  /*
68  for (unsigned s = 0; s < SlotIndex::NUM; ++s) {
69    indexList.push_back(createEntry(0, s));
70  }
71
72  unsigned index = gap * SlotIndex::NUM;
73  */
74
75  unsigned index = 0;
76
77  // Iterate over the the function.
78  for (MachineFunction::iterator mbbItr = mf->begin(), mbbEnd = mf->end();
79       mbbItr != mbbEnd; ++mbbItr) {
80    MachineBasicBlock *mbb = &*mbbItr;
81
82    // Insert an index for the MBB start.
83    push_back(createEntry(0, index));
84    SlotIndex blockStartIndex(back(), SlotIndex::LOAD);
85
86    index += gap * SlotIndex::NUM;
87
88    for (MachineBasicBlock::iterator miItr = mbb->begin(), miEnd = mbb->end();
89         miItr != miEnd; ++miItr) {
90      MachineInstr *mi = &*miItr;
91
92      if (miItr == mbb->getFirstTerminator()) {
93        push_back(createEntry(0, index));
94        terminatorGaps.insert(
95          std::make_pair(mbb, SlotIndex(back(), SlotIndex::PHI_BIT)));
96        index += gap * SlotIndex::NUM;
97      }
98
99      // Insert a store index for the instr.
100      push_back(createEntry(mi, index));
101
102      // Save this base index in the maps.
103      mi2iMap.insert(
104        std::make_pair(mi, SlotIndex(back(), SlotIndex::LOAD)));
105
106      ++functionSize;
107
108      unsigned Slots = mi->getDesc().getNumDefs();
109      if (Slots == 0)
110        Slots = 1;
111
112      index += (Slots + 1) * gap * SlotIndex::NUM;
113    }
114
115    if (mbb->getFirstTerminator() == mbb->end()) {
116      push_back(createEntry(0, index));
117      terminatorGaps.insert(
118        std::make_pair(mbb, SlotIndex(back(), SlotIndex::PHI_BIT)));
119      index += gap * SlotIndex::NUM;
120    }
121
122    SlotIndex blockEndIndex(back(), SlotIndex::STORE);
123    mbb2IdxMap.insert(
124      std::make_pair(mbb, std::make_pair(blockStartIndex, blockEndIndex)));
125
126    idx2MBBMap.push_back(IdxMBBPair(blockStartIndex, mbb));
127  }
128
129  // One blank instruction at the end.
130  push_back(createEntry(0, index));
131
132  // Sort the Idx2MBBMap
133  std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
134
135  DEBUG(dump());
136
137  // And we're done!
138  return false;
139}
140
141void SlotIndexes::renumber() {
142  assert(false && "SlotIndexes::runmuber is not fully implemented yet.");
143
144  // Compute numbering as follows:
145  // Grab an iterator to the start of the index list.
146  // Iterate over all MBBs, and within each MBB all MIs, keeping the MI
147  // iterator in lock-step (though skipping it over indexes which have
148  // null pointers in the instruction field).
149  // At each iteration assert that the instruction pointed to in the index
150  // is the same one pointed to by the MI iterator. This
151
152  // FIXME: This can be simplified. The mi2iMap_, Idx2MBBMap, etc. should
153  // only need to be set up once - when the first numbering is computed.
154
155  assert(false && "Renumbering not supported yet.");
156}
157
158void SlotIndexes::dump() const {
159  for (const IndexListEntry *itr = front(); itr != getTail();
160       itr = itr->getNext()) {
161    errs() << itr->getIndex() << " ";
162
163    if (itr->getInstr() != 0) {
164      errs() << *itr->getInstr();
165    } else {
166      errs() << "\n";
167    }
168  }
169
170  for (MBB2IdxMap::iterator itr = mbb2IdxMap.begin();
171       itr != mbb2IdxMap.end(); ++itr) {
172    errs() << "MBB " << itr->first->getNumber() << " (" << itr->first << ") - ["
173           << itr->second.first << ", " << itr->second.second << "]\n";
174  }
175}
176
177// Print a SlotIndex to a raw_ostream.
178void SlotIndex::print(raw_ostream &os) const {
179  os << getIndex();
180  if (isPHI())
181    os << "*";
182}
183
184// Dump a SlotIndex to stderr.
185void SlotIndex::dump() const {
186  print(errs());
187  errs() << "\n";
188}
189
190