C++ LBlock::getPhi方法代码示例

bool
RegisterAllocator::init()
{
    if (!insData.init(mir, graph.numInstructions()))
        return false;

    if (!entryPositions.reserve(graph.numBlocks()) || !exitPositions.reserve(graph.numBlocks()))
        return false;

    for (size_t i = 0; i < graph.numBlocks(); i++) {
        LBlock* block = graph.getBlock(i);
        for (LInstructionIterator ins = block->begin(); ins != block->end(); ins++)
            insData[ins->id()] = *ins;
        for (size_t j = 0; j < block->numPhis(); j++) {
            LPhi* phi = block->getPhi(j);
            insData[phi->id()] = phi;
        }

        CodePosition entry = block->numPhis() != 0
                             ? CodePosition(block->getPhi(0)->id(), CodePosition::INPUT)
                             : inputOf(block->firstInstructionWithId());
        CodePosition exit = outputOf(block->lastInstructionWithId());

        MOZ_ASSERT(block->mir()->id() == i);
        entryPositions.infallibleAppend(entry);
        exitPositions.infallibleAppend(exit);
    }

    return true;
}

void
JSONSpewer::spewLIR(MIRGraph *mir)
{
    if (!fp_)
        return;

    beginObjectProperty("lir");
    beginListProperty("blocks");

    for (MBasicBlockIterator i(mir->begin()); i != mir->end(); i++) {
        LBlock *block = i->lir();
        if (!block)
            continue;

        beginObject();
        integerProperty("number", i->id());

        beginListProperty("instructions");
        for (size_t p = 0; p < block->numPhis(); p++)
            spewLIns(block->getPhi(p));
        for (LInstructionIterator ins(block->begin()); ins != block->end(); ins++)
            spewLIns(*ins);
        endList();

        endObject();
    }

    endList();
    endObject();
}

bool
LiveRangeAllocator<VREG>::init()
{
    if (!RegisterAllocator::init())
        return false;

    liveIn = lir->mir()->allocate<BitSet*>(graph.numBlockIds());
    if (!liveIn)
        return false;

    // Initialize fixed intervals.
    for (size_t i = 0; i < AnyRegister::Total; i++) {
        AnyRegister reg = AnyRegister::FromCode(i);
        LiveInterval *interval = new LiveInterval(0);
        interval->setAllocation(LAllocation(reg));
        fixedIntervals[i] = interval;
    }

    fixedIntervalsUnion = new LiveInterval(0);

    if (!vregs.init(lir->mir(), graph.numVirtualRegisters()))
        return false;

    // Build virtual register objects
    for (size_t i = 0; i < graph.numBlocks(); i++) {
        if (mir->shouldCancel("LSRA create data structures (main loop)"))
            return false;

        LBlock *block = graph.getBlock(i);
        for (LInstructionIterator ins = block->begin(); ins != block->end(); ins++) {
            for (size_t j = 0; j < ins->numDefs(); j++) {
                LDefinition *def = ins->getDef(j);
                if (def->policy() != LDefinition::PASSTHROUGH) {
                    uint32_t reg = def->virtualRegister();
                    if (!vregs[reg].init(reg, block, *ins, def, /* isTemp */ false))
                        return false;
                }
            }

            for (size_t j = 0; j < ins->numTemps(); j++) {
                LDefinition *def = ins->getTemp(j);
                if (def->isBogusTemp())
                    continue;
                if (!vregs[def].init(def->virtualRegister(), block, *ins, def, /* isTemp */ true))
                    return false;
            }
        }
        for (size_t j = 0; j < block->numPhis(); j++) {
            LPhi *phi = block->getPhi(j);
            LDefinition *def = phi->getDef(0);
            if (!vregs[def].init(phi->id(), block, phi, def, /* isTemp */ false))
                return false;
        }
    }

    return true;
}

void
C1Spewer::spewIntervals(FILE *fp, MBasicBlock *block, LinearScanAllocator *regalloc, size_t &nextId)
{
    LBlock *lir = block->lir();
    if (!lir)
        return;

    for (size_t i = 0; i < lir->numPhis(); i++)
        spewIntervals(fp, regalloc, lir->getPhi(i), nextId);

    for (LInstructionIterator ins = lir->begin(); ins != lir->end(); ins++)
        spewIntervals(fp, regalloc, *ins, nextId);
}

void
C1Spewer::spewRanges(GenericPrinter& out, MBasicBlock* block, BacktrackingAllocator* regalloc)
{
    LBlock* lir = block->lir();
    if (!lir)
        return;

    for (size_t i = 0; i < lir->numPhis(); i++)
        spewRanges(out, regalloc, lir->getPhi(i));

    for (LInstructionIterator ins = lir->begin(); ins != lir->end(); ins++)
        spewRanges(out, regalloc, *ins);
}

bool
StupidAllocator::init()
{
    if (!RegisterAllocator::init())
        return false;

    if (!virtualRegisters.appendN((LDefinition*)nullptr, graph.numVirtualRegisters()))
        return false;

    for (size_t i = 0; i < graph.numBlocks(); i++) {
        LBlock* block = graph.getBlock(i);
        for (LInstructionIterator ins = block->begin(); ins != block->end(); ins++) {
            for (size_t j = 0; j < ins->numDefs(); j++) {
                LDefinition* def = ins->getDef(j);
                virtualRegisters[def->virtualRegister()] = def;
            }

            for (size_t j = 0; j < ins->numTemps(); j++) {
                LDefinition* def = ins->getTemp(j);
                if (def->isBogusTemp())
                    continue;
                virtualRegisters[def->virtualRegister()] = def;
            }
        }
        for (size_t j = 0; j < block->numPhis(); j++) {
            LPhi* phi = block->getPhi(j);
            LDefinition* def = phi->getDef(0);
            uint32_t vreg = def->virtualRegister();

            virtualRegisters[vreg] = def;
        }
    }

    // Assign physical registers to the tracked allocation.
    {
        registerCount = 0;
        LiveRegisterSet remainingRegisters(allRegisters_.asLiveSet());
        while (!remainingRegisters.emptyGeneral())
            registers[registerCount++].reg = AnyRegister(remainingRegisters.takeAnyGeneral());

        while (!remainingRegisters.emptyFloat())
            registers[registerCount++].reg = AnyRegister(remainingRegisters.takeAnyFloat());

        MOZ_ASSERT(registerCount <= MAX_REGISTERS);
    }

    return true;
}

void
StupidAllocator::syncForBlockEnd(LBlock *block, LInstruction *ins)
{
    // Sync any dirty registers, and update the synced state for phi nodes at
    // each successor of a block. We cannot conflate the storage for phis with
    // that of their inputs, as we cannot prove the live ranges of the phi and
    // its input do not overlap. The values for the two may additionally be
    // different, as the phi could be for the value of the input in a previous
    // loop iteration.

    for (size_t i = 0; i < registerCount; i++)
        syncRegister(ins, i);

    LMoveGroup *group = nullptr;

    MBasicBlock *successor = block->mir()->successorWithPhis();
    if (successor) {
        uint32_t position = block->mir()->positionInPhiSuccessor();
        LBlock *lirsuccessor = graph.getBlock(successor->id());
        for (size_t i = 0; i < lirsuccessor->numPhis(); i++) {
            LPhi *phi = lirsuccessor->getPhi(i);

            uint32_t sourcevreg = phi->getOperand(position)->toUse()->virtualRegister();
            uint32_t destvreg = phi->getDef(0)->virtualRegister();

            if (sourcevreg == destvreg)
                continue;

            LAllocation *source = stackLocation(sourcevreg);
            LAllocation *dest = stackLocation(destvreg);

            if (!group) {
                // The moves we insert here need to happen simultaneously with
                // each other, yet after any existing moves before the instruction.
                LMoveGroup *input = getInputMoveGroup(ins->id());
                if (input->numMoves() == 0) {
                    group = input;
                } else {
                    group = new LMoveGroup(alloc());
                    block->insertAfter(input, group);
                }
            }

            group->add(source, dest);
        }
    }
}

bool
RegisterAllocator::init()
{
    if (!insData.init(mir, graph.numInstructions()))
        return false;

    for (size_t i = 0; i < graph.numBlocks(); i++) {
        LBlock* block = graph.getBlock(i);
        for (LInstructionIterator ins = block->begin(); ins != block->end(); ins++)
            insData[ins->id()] = *ins;
        for (size_t j = 0; j < block->numPhis(); j++) {
            LPhi* phi = block->getPhi(j);
            insData[phi->id()] = phi;
        }
    }

    return true;
}

bool
RegisterAllocator::init()
{
    if (!insData.init(lir->mir(), graph.numInstructions()))
        return false;

    for (size_t i = 0; i < graph.numBlocks(); i++) {
        LBlock *block = graph.getBlock(i);
        for (LInstructionIterator ins = block->begin(); ins != block->end(); ins++)
            insData[*ins].init(*ins, block);
        for (size_t j = 0; j < block->numPhis(); j++) {
            LPhi *phi = block->getPhi(j);
            insData[phi].init(phi, block);
        }
    }

    return true;
}

bool
GreedyAllocator::buildPhiMoves(LBlock *block)
{
    IonSpew(IonSpew_RegAlloc, " Merging phi state."); 

    phiMoves = Mover();

    MBasicBlock *mblock = block->mir();
    if (!mblock->successorWithPhis())
        return true;

    // Insert moves from our state into our successor's phi.
    uint32 pos = mblock->positionInPhiSuccessor();
    LBlock *successor = mblock->successorWithPhis()->lir();
    for (size_t i = 0; i < successor->numPhis(); i++) {
        LPhi *phi = successor->getPhi(i);
        JS_ASSERT(phi->numDefs() == 1);

        VirtualRegister *phiReg = getVirtualRegister(phi->getDef(0));
        allocateStack(phiReg);

        LAllocation *in = phi->getOperand(pos);
        VirtualRegister *inReg = getVirtualRegister(in->toUse());
        allocateStack(inReg);

        // Try to get a register for the input.
        if (!inReg->hasRegister() && !allocatableRegs().empty(inReg->isDouble())) {
            if (!allocateReg(inReg))
                return false;
        }

        // Add a move from the input to the phi.
        if (inReg->hasRegister()) {
            if (!phiMoves.move(inReg->reg(), phiReg->backingStack()))
                return false;
        } else {
            if (!phiMoves.move(inReg->backingStack(), phiReg->backingStack()))
                return false;
        }
    }

    return true;
}

void
RegisterAllocator::dumpInstructions()
{
#ifdef DEBUG
    fprintf(stderr, "Instructions:\n");

    for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
        LBlock* block = graph.getBlock(blockIndex);
        MBasicBlock* mir = block->mir();

        fprintf(stderr, "\nBlock %lu", static_cast<unsigned long>(blockIndex));
        for (size_t i = 0; i < mir->numSuccessors(); i++)
            fprintf(stderr, " [successor %u]", mir->getSuccessor(i)->id());
        fprintf(stderr, "\n");

        for (size_t i = 0; i < block->numPhis(); i++) {
            LPhi* phi = block->getPhi(i);

            fprintf(stderr, "[%u,%u Phi] [def %s]",
                    inputOf(phi).bits(),
                    outputOf(phi).bits(),
                    phi->getDef(0)->toString());
            for (size_t j = 0; j < phi->numOperands(); j++)
                fprintf(stderr, " [use %s]", phi->getOperand(j)->toString());
            fprintf(stderr, "\n");
        }

        for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
            LInstruction* ins = *iter;

            fprintf(stderr, "[");
            if (ins->id() != 0)
                fprintf(stderr, "%u,%u ", inputOf(ins).bits(), outputOf(ins).bits());
            fprintf(stderr, "%s]", ins->opName());

            if (ins->isMoveGroup()) {
                LMoveGroup* group = ins->toMoveGroup();
                for (int i = group->numMoves() - 1; i >= 0; i--) {
                    // Use two printfs, as LAllocation::toString is not reentant.
                    fprintf(stderr, " [%s", group->getMove(i).from()->toString());
                    fprintf(stderr, " -> %s]", group->getMove(i).to()->toString());
                }
                fprintf(stderr, "\n");
                continue;
            }

            for (size_t i = 0; i < ins->numDefs(); i++)
                fprintf(stderr, " [def %s]", ins->getDef(i)->toString());

            for (size_t i = 0; i < ins->numTemps(); i++) {
                LDefinition* temp = ins->getTemp(i);
                if (!temp->isBogusTemp())
                    fprintf(stderr, " [temp %s]", temp->toString());
            }

            for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
                if (!alloc->isBogus())
                    fprintf(stderr, " [use %s]", alloc->toString());
            }

            fprintf(stderr, "\n");
        }
    }
    fprintf(stderr, "\n");
#endif // DEBUG
}

void
AllocationIntegrityState::dump()
{
#ifdef DEBUG
    fprintf(stderr, "Register Allocation Integrity State:\n");

    for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); blockIndex++) {
        LBlock* block = graph.getBlock(blockIndex);
        MBasicBlock* mir = block->mir();

        fprintf(stderr, "\nBlock %lu", static_cast<unsigned long>(blockIndex));
        for (size_t i = 0; i < mir->numSuccessors(); i++)
            fprintf(stderr, " [successor %u]", mir->getSuccessor(i)->id());
        fprintf(stderr, "\n");

        for (size_t i = 0; i < block->numPhis(); i++) {
            const InstructionInfo& info = blocks[blockIndex].phis[i];
            LPhi* phi = block->getPhi(i);
            CodePosition input(block->getPhi(0)->id(), CodePosition::INPUT);
            CodePosition output(block->getPhi(block->numPhis() - 1)->id(), CodePosition::OUTPUT);

            fprintf(stderr, "[%u,%u Phi] [def %s] ",
                    input.bits(),
                    output.bits(),
                    phi->getDef(0)->toString());
            for (size_t j = 0; j < phi->numOperands(); j++)
                fprintf(stderr, " [use %s]", info.inputs[j].toString());
            fprintf(stderr, "\n");
        }

        for (LInstructionIterator iter = block->begin(); iter != block->end(); iter++) {
            LInstruction* ins = *iter;
            const InstructionInfo& info = instructions[ins->id()];

            CodePosition input(ins->id(), CodePosition::INPUT);
            CodePosition output(ins->id(), CodePosition::OUTPUT);

            fprintf(stderr, "[");
            if (input != CodePosition::MIN)
                fprintf(stderr, "%u,%u ", input.bits(), output.bits());
            fprintf(stderr, "%s]", ins->opName());

            if (ins->isMoveGroup()) {
                LMoveGroup* group = ins->toMoveGroup();
                for (int i = group->numMoves() - 1; i >= 0; i--) {
                    // Use two printfs, as LAllocation::toString is not reentrant.
                    fprintf(stderr, " [%s", group->getMove(i).from()->toString());
                    fprintf(stderr, " -> %s]", group->getMove(i).to()->toString());
                }
                fprintf(stderr, "\n");
                continue;
            }

            for (size_t i = 0; i < ins->numDefs(); i++)
                fprintf(stderr, " [def %s]", ins->getDef(i)->toString());

            for (size_t i = 0; i < ins->numTemps(); i++) {
                LDefinition* temp = ins->getTemp(i);
                if (!temp->isBogusTemp())
                    fprintf(stderr, " [temp v%u %s]", info.temps[i].virtualRegister(),
                           temp->toString());
            }

            size_t index = 0;
            for (LInstruction::InputIterator alloc(*ins); alloc.more(); alloc.next()) {
                fprintf(stderr, " [use %s", info.inputs[index++].toString());
                if (!alloc->isConstant())
                    fprintf(stderr, " %s", alloc->toString());
                fprintf(stderr, "]");
            }

            fprintf(stderr, "\n");
        }
    }

    // Print discovered allocations at the ends of blocks, in the order they
    // were discovered.

    Vector<IntegrityItem, 20, SystemAllocPolicy> seenOrdered;
    seenOrdered.appendN(IntegrityItem(), seen.count());

    for (IntegrityItemSet::Enum iter(seen); !iter.empty(); iter.popFront()) {
        IntegrityItem item = iter.front();
        seenOrdered[item.index] = item;
    }

    if (!seenOrdered.empty()) {
        fprintf(stderr, "Intermediate Allocations:\n");

        for (size_t i = 0; i < seenOrdered.length(); i++) {
            IntegrityItem item = seenOrdered[i];
            fprintf(stderr, "  block %u reg v%u alloc %s\n",
                   item.block->mir()->id(), item.vreg, item.alloc.toString());
        }
    }

    fprintf(stderr, "\n");
#endif
}

bool
LiveRangeAllocator<VREG>::buildLivenessInfo()
{
    if (!init())
        return false;

    Vector<MBasicBlock *, 1, SystemAllocPolicy> loopWorkList;
    BitSet *loopDone = BitSet::New(alloc(), graph.numBlockIds());
    if (!loopDone)
        return false;

    for (size_t i = graph.numBlocks(); i > 0; i--) {
        if (mir->shouldCancel("Build Liveness Info (main loop)"))
            return false;

        LBlock *block = graph.getBlock(i - 1);
        MBasicBlock *mblock = block->mir();

        BitSet *live = BitSet::New(alloc(), graph.numVirtualRegisters());
        if (!live)
            return false;
        liveIn[mblock->id()] = live;

        // Propagate liveIn from our successors to us
        for (size_t i = 0; i < mblock->lastIns()->numSuccessors(); i++) {
            MBasicBlock *successor = mblock->lastIns()->getSuccessor(i);
            // Skip backedges, as we fix them up at the loop header.
            if (mblock->id() < successor->id())
                live->insertAll(liveIn[successor->id()]);
        }

        // Add successor phis
        if (mblock->successorWithPhis()) {
            LBlock *phiSuccessor = mblock->successorWithPhis()->lir();
            for (unsigned int j = 0; j < phiSuccessor->numPhis(); j++) {
                LPhi *phi = phiSuccessor->getPhi(j);
                LAllocation *use = phi->getOperand(mblock->positionInPhiSuccessor());
                uint32_t reg = use->toUse()->virtualRegister();
                live->insert(reg);
            }
        }

        // Variables are assumed alive for the entire block, a define shortens
        // the interval to the point of definition.
        for (BitSet::Iterator liveRegId(*live); liveRegId; liveRegId++) {
            if (!vregs[*liveRegId].getInterval(0)->addRangeAtHead(inputOf(block->firstId()),
                                                                  outputOf(block->lastId()).next()))
            {
                return false;
            }
        }

        // Shorten the front end of live intervals for live variables to their
        // point of definition, if found.
        for (LInstructionReverseIterator ins = block->rbegin(); ins != block->rend(); ins++) {
            // Calls may clobber registers, so force a spill and reload around the callsite.
            if (ins->isCall()) {
                for (AnyRegisterIterator iter(allRegisters_); iter.more(); iter++) {
                    if (forLSRA) {
                        if (!addFixedRangeAtHead(*iter, inputOf(*ins), outputOf(*ins)))
                            return false;
                    } else {
                        bool found = false;
                        for (size_t i = 0; i < ins->numDefs(); i++) {
                            if (ins->getDef(i)->isPreset() &&
                                *ins->getDef(i)->output() == LAllocation(*iter)) {
                                found = true;
                                break;
                            }
                        }
                        if (!found && !addFixedRangeAtHead(*iter, outputOf(*ins), outputOf(*ins).next()))
                            return false;
                    }
                }
            }

            for (size_t i = 0; i < ins->numDefs(); i++) {
                if (ins->getDef(i)->policy() != LDefinition::PASSTHROUGH) {
                    LDefinition *def = ins->getDef(i);

                    CodePosition from;
                    if (def->policy() == LDefinition::PRESET && def->output()->isRegister() && forLSRA) {
                        // The fixed range covers the current instruction so the
                        // interval for the virtual register starts at the next
                        // instruction. If the next instruction has a fixed use,
                        // this can lead to unnecessary register moves. To avoid
                        // special handling for this, assert the next instruction
                        // has no fixed uses. defineFixed guarantees this by inserting
                        // an LNop.
                        JS_ASSERT(!NextInstructionHasFixedUses(block, *ins));
                        AnyRegister reg = def->output()->toRegister();
                        if (!addFixedRangeAtHead(reg, inputOf(*ins), outputOf(*ins).next()))
                            return false;
                        from = outputOf(*ins).next();
                    } else {
                        from = forLSRA ? inputOf(*ins) : outputOf(*ins);
                    }

                    if (def->policy() == LDefinition::MUST_REUSE_INPUT) {
                        // MUST_REUSE_INPUT is implemented by allocating an output
//.........这里部分代码省略.........