SlotIndexes.cpp revision ce665bd2e2b581ab0858d1afe359192bac96b868
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#include "llvm/Support/ManagedStatic.h" 17#include "llvm/Target/TargetInstrInfo.h" 18 19using namespace llvm; 20 21 22// Yep - these are thread safe. See the header for details. 23namespace { 24 25 26 class EmptyIndexListEntry : public IndexListEntry { 27 public: 28 EmptyIndexListEntry() : IndexListEntry(EMPTY_KEY) {} 29 }; 30 31 class TombstoneIndexListEntry : public IndexListEntry { 32 public: 33 TombstoneIndexListEntry() : IndexListEntry(TOMBSTONE_KEY) {} 34 }; 35 36 // The following statics are thread safe. They're read only, and you 37 // can't step from them to any other list entries. 38 ManagedStatic<EmptyIndexListEntry> IndexListEntryEmptyKey; 39 ManagedStatic<TombstoneIndexListEntry> IndexListEntryTombstoneKey; 40} 41 42char SlotIndexes::ID = 0; 43INITIALIZE_PASS(SlotIndexes, "slotindexes", 44 "Slot index numbering", false, false) 45 46IndexListEntry* IndexListEntry::getEmptyKeyEntry() { 47 return &*IndexListEntryEmptyKey; 48} 49 50IndexListEntry* IndexListEntry::getTombstoneKeyEntry() { 51 return &*IndexListEntryTombstoneKey; 52} 53 54 55void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const { 56 au.setPreservesAll(); 57 MachineFunctionPass::getAnalysisUsage(au); 58} 59 60void SlotIndexes::releaseMemory() { 61 mi2iMap.clear(); 62 mbb2IdxMap.clear(); 63 idx2MBBMap.clear(); 64 clearList(); 65} 66 67bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) { 68 69 // Compute numbering as follows: 70 // Grab an iterator to the start of the index list. 71 // Iterate over all MBBs, and within each MBB all MIs, keeping the MI 72 // iterator in lock-step (though skipping it over indexes which have 73 // null pointers in the instruction field). 74 // At each iteration assert that the instruction pointed to in the index 75 // is the same one pointed to by the MI iterator. This 76 77 // FIXME: This can be simplified. The mi2iMap_, Idx2MBBMap, etc. should 78 // only need to be set up once after the first numbering is computed. 79 80 mf = &fn; 81 initList(); 82 83 // Check that the list contains only the sentinal. 84 assert(indexListHead->getNext() == 0 && 85 "Index list non-empty at initial numbering?"); 86 assert(idx2MBBMap.empty() && 87 "Index -> MBB mapping non-empty at initial numbering?"); 88 assert(mbb2IdxMap.empty() && 89 "MBB -> Index mapping non-empty at initial numbering?"); 90 assert(mi2iMap.empty() && 91 "MachineInstr -> Index mapping non-empty at initial numbering?"); 92 93 functionSize = 0; 94 unsigned index = 0; 95 96 push_back(createEntry(0, index)); 97 98 // Iterate over the function. 99 for (MachineFunction::iterator mbbItr = mf->begin(), mbbEnd = mf->end(); 100 mbbItr != mbbEnd; ++mbbItr) { 101 MachineBasicBlock *mbb = &*mbbItr; 102 103 // Insert an index for the MBB start. 104 SlotIndex blockStartIndex(back(), SlotIndex::LOAD); 105 106 index += SlotIndex::NUM; 107 108 for (MachineBasicBlock::iterator miItr = mbb->begin(), miEnd = mbb->end(); 109 miItr != miEnd; ++miItr) { 110 MachineInstr *mi = miItr; 111 if (mi->isDebugValue()) 112 continue; 113 114 // Insert a store index for the instr. 115 push_back(createEntry(mi, index)); 116 117 // Save this base index in the maps. 118 mi2iMap.insert( 119 std::make_pair(mi, SlotIndex(back(), SlotIndex::LOAD))); 120 121 ++functionSize; 122 123 unsigned Slots = mi->getDesc().getNumDefs(); 124 if (Slots == 0) 125 Slots = 1; 126 127 index += (Slots + 1) * SlotIndex::NUM; 128 } 129 130 // One blank instruction at the end. 131 push_back(createEntry(0, index)); 132 133 SlotIndex blockEndIndex(back(), SlotIndex::LOAD); 134 mbb2IdxMap.insert( 135 std::make_pair(mbb, std::make_pair(blockStartIndex, blockEndIndex))); 136 137 idx2MBBMap.push_back(IdxMBBPair(blockStartIndex, mbb)); 138 } 139 140 // Sort the Idx2MBBMap 141 std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare()); 142 143 DEBUG(dump()); 144 145 // And we're done! 146 return false; 147} 148 149void SlotIndexes::renumberIndexes() { 150 151 // Renumber updates the index of every element of the index list. 152 // If all instrs in the function have been allocated an index (which has been 153 // placed in the index list in the order of instruction iteration) then the 154 // resulting numbering will match what would have been generated by the 155 // pass during the initial numbering of the function if the new instructions 156 // had been present. 157 158 functionSize = 0; 159 unsigned index = 0; 160 161 for (IndexListEntry *curEntry = front(); curEntry != getTail(); 162 curEntry = curEntry->getNext()) { 163 164 curEntry->setIndex(index); 165 166 if (curEntry->getInstr() == 0) { 167 // MBB start entry. Just step index by 1. 168 index += SlotIndex::NUM; 169 } 170 else { 171 ++functionSize; 172 unsigned Slots = curEntry->getInstr()->getDesc().getNumDefs(); 173 if (Slots == 0) 174 Slots = 1; 175 176 index += (Slots + 1) * SlotIndex::NUM; 177 } 178 } 179} 180 181void SlotIndexes::dump() const { 182 for (const IndexListEntry *itr = front(); itr != getTail(); 183 itr = itr->getNext()) { 184 dbgs() << itr->getIndex() << " "; 185 186 if (itr->getInstr() != 0) { 187 dbgs() << *itr->getInstr(); 188 } else { 189 dbgs() << "\n"; 190 } 191 } 192 193 for (MBB2IdxMap::const_iterator itr = mbb2IdxMap.begin(); 194 itr != mbb2IdxMap.end(); ++itr) { 195 dbgs() << "MBB " << itr->first->getNumber() << " (" << itr->first << ") - [" 196 << itr->second.first << ", " << itr->second.second << "]\n"; 197 } 198} 199 200// Print a SlotIndex to a raw_ostream. 201void SlotIndex::print(raw_ostream &os) const { 202 os << entry().getIndex() << "LudS"[getSlot()]; 203} 204 205// Dump a SlotIndex to stderr. 206void SlotIndex::dump() const { 207 print(dbgs()); 208 dbgs() << "\n"; 209} 210 211