Esempio n. 1
0
bool
RangeAnalysis::analyze()
{
    int numBlocks = 0;
    for (PostorderIterator i(graph_.poBegin()); i != graph_.poEnd(); i++) {
        numBlocks++;
        MBasicBlock *curBlock = *i;
        if (!curBlock->isLoopHeader())
            continue;
        for (MPhiIterator pi(curBlock->phisBegin()); pi != curBlock->phisEnd(); pi++)
            if (!pi->initCounts())
                return false;
    }

    IonSpew(IonSpew_Range, "Doing range propagation");
    MDefinitionVector worklist;

    for (ReversePostorderIterator block(graph_.rpoBegin()); block != graph_.rpoEnd(); block++) {
        for (MDefinitionIterator iter(*block); iter; iter++) {
            MDefinition *def = *iter;

            AddToWorklist(worklist, def);

        }
    }
    size_t iters = 0;

    while (!worklist.empty()) {
        MDefinition *def = PopFromWorklist(worklist);
        IonSpew(IonSpew_Range, "recomputing range on %d", def->id());
        SpewRange(def);
        if (!def->earlyAbortCheck() && def->recomputeRange()) {
            JS_ASSERT(def->range()->lower() <= def->range()->upper());
            IonSpew(IonSpew_Range, "Range changed; adding consumers");
            IonSpew(IonSpew_Range, "New range for %d is: (%d, %d)", def->id(), def->range()->lower(), def->range()->upper());
            for (MUseDefIterator use(def); use; use++) {
                if(!AddToWorklist(worklist, use.def()))
                    return false;
            }
        }
        iters++;
        if (iters >= numBlocks * 100)
            return false;
    }
    // Cleanup (in case we stopped due to MAX_ITERS)
    for(size_t i = 0; i < worklist.length(); i++)
        worklist[i]->setNotInWorklist();


#ifdef DEBUG
    for (ReversePostorderIterator block(graph_.rpoBegin()); block != graph_.rpoEnd(); block++) {
        for (MDefinitionIterator iter(*block); iter; iter++) {
            MDefinition *def = *iter;
            SpewRange(def);
            JS_ASSERT(def->range()->lower() <= def->range()->upper());
            JS_ASSERT(!def->isInWorklist());
        }
    }
#endif
    return true;
}