| //===-- SlotIndexes.cpp - Slot Indexes Pass ------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/CodeGen/SlotIndexes.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/Config/llvm-config.h" |
| #include "llvm/InitializePasses.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "slotindexes" |
| |
| char SlotIndexes::ID = 0; |
| |
| SlotIndexes::SlotIndexes() : MachineFunctionPass(ID), mf(nullptr) { |
| initializeSlotIndexesPass(*PassRegistry::getPassRegistry()); |
| } |
| |
| SlotIndexes::~SlotIndexes() { |
| // The indexList's nodes are all allocated in the BumpPtrAllocator. |
| indexList.clearAndLeakNodesUnsafely(); |
| } |
| |
| INITIALIZE_PASS(SlotIndexes, DEBUG_TYPE, |
| "Slot index numbering", false, false) |
| |
| STATISTIC(NumLocalRenum, "Number of local renumberings"); |
| |
| void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const { |
| au.setPreservesAll(); |
| MachineFunctionPass::getAnalysisUsage(au); |
| } |
| |
| void SlotIndexes::releaseMemory() { |
| mi2iMap.clear(); |
| MBBRanges.clear(); |
| idx2MBBMap.clear(); |
| indexList.clear(); |
| ileAllocator.Reset(); |
| } |
| |
| bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) { |
| |
| // Compute numbering as follows: |
| // Grab an iterator to the start of the index list. |
| // Iterate over all MBBs, and within each MBB all MIs, keeping the MI |
| // iterator in lock-step (though skipping it over indexes which have |
| // null pointers in the instruction field). |
| // At each iteration assert that the instruction pointed to in the index |
| // is the same one pointed to by the MI iterator. This |
| |
| // FIXME: This can be simplified. The mi2iMap_, Idx2MBBMap, etc. should |
| // only need to be set up once after the first numbering is computed. |
| |
| mf = &fn; |
| |
| // Check that the list contains only the sentinal. |
| assert(indexList.empty() && "Index list non-empty at initial numbering?"); |
| assert(idx2MBBMap.empty() && |
| "Index -> MBB mapping non-empty at initial numbering?"); |
| assert(MBBRanges.empty() && |
| "MBB -> Index mapping non-empty at initial numbering?"); |
| assert(mi2iMap.empty() && |
| "MachineInstr -> Index mapping non-empty at initial numbering?"); |
| |
| unsigned index = 0; |
| MBBRanges.resize(mf->getNumBlockIDs()); |
| idx2MBBMap.reserve(mf->size()); |
| |
| indexList.push_back(createEntry(nullptr, index)); |
| |
| // Iterate over the function. |
| for (MachineBasicBlock &MBB : *mf) { |
| // Insert an index for the MBB start. |
| SlotIndex blockStartIndex(&indexList.back(), SlotIndex::Slot_Block); |
| |
| for (MachineInstr &MI : MBB) { |
| if (MI.isDebugOrPseudoInstr()) |
| continue; |
| |
| // Insert a store index for the instr. |
| indexList.push_back(createEntry(&MI, index += SlotIndex::InstrDist)); |
| |
| // Save this base index in the maps. |
| mi2iMap.insert(std::make_pair( |
| &MI, SlotIndex(&indexList.back(), SlotIndex::Slot_Block))); |
| } |
| |
| // We insert one blank instructions between basic blocks. |
| indexList.push_back(createEntry(nullptr, index += SlotIndex::InstrDist)); |
| |
| MBBRanges[MBB.getNumber()].first = blockStartIndex; |
| MBBRanges[MBB.getNumber()].second = SlotIndex(&indexList.back(), |
| SlotIndex::Slot_Block); |
| idx2MBBMap.push_back(IdxMBBPair(blockStartIndex, &MBB)); |
| } |
| |
| // Sort the Idx2MBBMap |
| llvm::sort(idx2MBBMap, less_first()); |
| |
| LLVM_DEBUG(mf->print(dbgs(), this)); |
| |
| // And we're done! |
| return false; |
| } |
| |
| void SlotIndexes::removeMachineInstrFromMaps(MachineInstr &MI, |
| bool AllowBundled) { |
| assert((AllowBundled || !MI.isBundledWithPred()) && |
| "Use removeSingleMachineInstrFromMaps() instead"); |
| Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI); |
| if (mi2iItr == mi2iMap.end()) |
| return; |
| |
| SlotIndex MIIndex = mi2iItr->second; |
| IndexListEntry &MIEntry = *MIIndex.listEntry(); |
| assert(MIEntry.getInstr() == &MI && "Instruction indexes broken."); |
| mi2iMap.erase(mi2iItr); |
| // FIXME: Eventually we want to actually delete these indexes. |
| MIEntry.setInstr(nullptr); |
| } |
| |
| void SlotIndexes::removeSingleMachineInstrFromMaps(MachineInstr &MI) { |
| Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI); |
| if (mi2iItr == mi2iMap.end()) |
| return; |
| |
| SlotIndex MIIndex = mi2iItr->second; |
| IndexListEntry &MIEntry = *MIIndex.listEntry(); |
| assert(MIEntry.getInstr() == &MI && "Instruction indexes broken."); |
| mi2iMap.erase(mi2iItr); |
| |
| // When removing the first instruction of a bundle update mapping to next |
| // instruction. |
| if (MI.isBundledWithSucc()) { |
| // Only the first instruction of a bundle should have an index assigned. |
| assert(!MI.isBundledWithPred() && "Should be first bundle instruction"); |
| |
| MachineBasicBlock::instr_iterator Next = std::next(MI.getIterator()); |
| MachineInstr &NextMI = *Next; |
| MIEntry.setInstr(&NextMI); |
| mi2iMap.insert(std::make_pair(&NextMI, MIIndex)); |
| return; |
| } else { |
| // FIXME: Eventually we want to actually delete these indexes. |
| MIEntry.setInstr(nullptr); |
| } |
| } |
| |
| // Renumber indexes locally after curItr was inserted, but failed to get a new |
| // index. |
| void SlotIndexes::renumberIndexes(IndexList::iterator curItr) { |
| // Number indexes with half the default spacing so we can catch up quickly. |
| const unsigned Space = SlotIndex::InstrDist/2; |
| static_assert((Space & 3) == 0, "InstrDist must be a multiple of 2*NUM"); |
| |
| IndexList::iterator startItr = std::prev(curItr); |
| unsigned index = startItr->getIndex(); |
| do { |
| curItr->setIndex(index += Space); |
| ++curItr; |
| // If the next index is bigger, we have caught up. |
| } while (curItr != indexList.end() && curItr->getIndex() <= index); |
| |
| LLVM_DEBUG(dbgs() << "\n*** Renumbered SlotIndexes " << startItr->getIndex() |
| << '-' << index << " ***\n"); |
| ++NumLocalRenum; |
| } |
| |
| // Repair indexes after adding and removing instructions. |
| void SlotIndexes::repairIndexesInRange(MachineBasicBlock *MBB, |
| MachineBasicBlock::iterator Begin, |
| MachineBasicBlock::iterator End) { |
| // FIXME: Is this really necessary? The only caller repairIntervalsForRange() |
| // does the same thing. |
| // Find anchor points, which are at the beginning/end of blocks or at |
| // instructions that already have indexes. |
| while (Begin != MBB->begin() && !hasIndex(*Begin)) |
| --Begin; |
| while (End != MBB->end() && !hasIndex(*End)) |
| ++End; |
| |
| bool includeStart = (Begin == MBB->begin()); |
| SlotIndex startIdx; |
| if (includeStart) |
| startIdx = getMBBStartIdx(MBB); |
| else |
| startIdx = getInstructionIndex(*Begin); |
| |
| SlotIndex endIdx; |
| if (End == MBB->end()) |
| endIdx = getMBBEndIdx(MBB); |
| else |
| endIdx = getInstructionIndex(*End); |
| |
| // FIXME: Conceptually, this code is implementing an iterator on MBB that |
| // optionally includes an additional position prior to MBB->begin(), indicated |
| // by the includeStart flag. This is done so that we can iterate MIs in a MBB |
| // in parallel with SlotIndexes, but there should be a better way to do this. |
| IndexList::iterator ListB = startIdx.listEntry()->getIterator(); |
| IndexList::iterator ListI = endIdx.listEntry()->getIterator(); |
| MachineBasicBlock::iterator MBBI = End; |
| bool pastStart = false; |
| while (ListI != ListB || MBBI != Begin || (includeStart && !pastStart)) { |
| assert(ListI->getIndex() >= startIdx.getIndex() && |
| (includeStart || !pastStart) && |
| "Decremented past the beginning of region to repair."); |
| |
| MachineInstr *SlotMI = ListI->getInstr(); |
| MachineInstr *MI = (MBBI != MBB->end() && !pastStart) ? &*MBBI : nullptr; |
| bool MBBIAtBegin = MBBI == Begin && (!includeStart || pastStart); |
| |
| if (SlotMI == MI && !MBBIAtBegin) { |
| --ListI; |
| if (MBBI != Begin) |
| --MBBI; |
| else |
| pastStart = true; |
| } else if (MI && mi2iMap.find(MI) == mi2iMap.end()) { |
| if (MBBI != Begin) |
| --MBBI; |
| else |
| pastStart = true; |
| } else { |
| --ListI; |
| if (SlotMI) |
| removeMachineInstrFromMaps(*SlotMI); |
| } |
| } |
| |
| // In theory this could be combined with the previous loop, but it is tricky |
| // to update the IndexList while we are iterating it. |
| for (MachineBasicBlock::iterator I = End; I != Begin;) { |
| --I; |
| MachineInstr &MI = *I; |
| if (!MI.isDebugOrPseudoInstr() && mi2iMap.find(&MI) == mi2iMap.end()) |
| insertMachineInstrInMaps(MI); |
| } |
| } |
| |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| LLVM_DUMP_METHOD void SlotIndexes::dump() const { |
| for (const IndexListEntry &ILE : indexList) { |
| dbgs() << ILE.getIndex() << " "; |
| |
| if (ILE.getInstr()) { |
| dbgs() << *ILE.getInstr(); |
| } else { |
| dbgs() << "\n"; |
| } |
| } |
| |
| for (unsigned i = 0, e = MBBRanges.size(); i != e; ++i) |
| dbgs() << "%bb." << i << "\t[" << MBBRanges[i].first << ';' |
| << MBBRanges[i].second << ")\n"; |
| } |
| #endif |
| |
| // Print a SlotIndex to a raw_ostream. |
| void SlotIndex::print(raw_ostream &os) const { |
| if (isValid()) |
| os << listEntry()->getIndex() << "Berd"[getSlot()]; |
| else |
| os << "invalid"; |
| } |
| |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| // Dump a SlotIndex to stderr. |
| LLVM_DUMP_METHOD void SlotIndex::dump() const { |
| print(dbgs()); |
| dbgs() << "\n"; |
| } |
| #endif |