BFLateBypass.cc

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/**
 * @file BFLateBypass.cc
 *
 * Definition of BFLateBypass class
 *
 * Performs a bypass of noy-yet-scheduled result into already scheduled
 * use of the value.
 *
 * @author Heikki Kultala 2014-2020(heikki.kultala-no.spam-tuni.fi)
 * @note rating: red
 */
 
#include "BFLateBypass.hh"
#include "BFScheduleBU.hh"
#include "BFScheduleExact.hh"
 
#include "SimpleResourceManager.hh"
#include "DataDependenceGraph.hh"
#include "MoveNode.hh"
#include "Move.hh"
 
#include "Bus.hh"
#include "MoveNodeDuplicator.hh"
#include "BFMergeAndKeepUser.hh"
 
//#define DEBUG_BUBBLEFISH_SCHEDULER
//#define DEBUG_LOOP_SCHEDULER
 
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
#define DEBUG_LOOP_SCHEDULER
#endif
 
 
bool
BFLateBypass::operator()() {
    // if already has guard operation, cannot have source operation.
    if (dst_.isGuardOperation()) {
        return false;
    }
 
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
   std::cerr << "\t\tPerforming late bypass: " << dst_.toString() <<std::endl;
#else
#ifdef DEBUG_LOOP_SCHEDULER
    if (ii() != 0) {
        std::cerr << "\t\tPerforming late bypass, dst: "
                  << dst_.toString() << std::endl;
    }
#endif
#endif
    originalCycle_ = dst_.cycle();
    originalBus_ = &dst_.move().bus();
    MoveNode* prologMN = ii() ?  duplicator().getMoveNode(dst_) : NULL;
    if (prologMN != NULL) {
        prologBus_ = &prologMN->move().bus();
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\t\t\tProlog move: " << prologMN->toString()
                  << std::endl;
        std::cerr << "\t\t\t\tLate bypass saving prolog bus: "
                  << prologBus_->name() << std::endl;
#endif
    }
 
    bool dstTriggering = dst_.move().isTriggering();
    // this one did not create the prolog copy so do not remove it here.
    unassign(dst_, false);
 
    // Take the predecssors so that they can be notified because their
    // antideps may change
    // makes compiling too slow, disabled for now
    DataDependenceGraph::NodeSet pred = ddg().predecessors(dst_);
 
    if (!runPostChild(new BFMergeAndKeepUser(sched_, src_, dst_))) {
        assign(originalCycle_, dst_, originalBus_, NULL, NULL, prologBus_);
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\t\tMerge and keep fail!" << std::endl;
#endif
        return false;
    }
 
    // TODO: this does too much optimizations?
 
    BFOptimization* sched = NULL;
    if ((dst_.move().isControlFlowMove() && dstTriggering) ||
        (ii() != 0 &&
         static_cast<DataDependenceGraph*>(ddg().rootGraph())->
         writesJumpGuard(dst_))) {
        if (lc_ < originalCycle_) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
            std::cerr << "Late bypass fail: must use originalcycle "
                "which is too late!!!" << std::endl;
#endif
            undo();
            return false;
        }
        sched = new BFScheduleExact(sched_, dst_, originalCycle_);
    } else {
        sched = new BFScheduleBU(sched_, dst_, lc_, false, false, false);
    }
    if ((*sched)()) {
        // TODO: get this from bypass distance setting?
        if (dst_.cycle() + 3 < originalCycle_) {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
            std::cerr << "\t\t\tToo long bypass dist, fail late bypass!"
                      << std::endl;
#endif
            sched->undo();
            delete sched;
            undo();
            return false;
        }
 
        postChildren_.push(sched);
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\tLate bypass ok: " << dst_.toString() << std::endl;
#endif
 
        // now notify antideps sources
        for (auto i : pred) {
            mightBeReady(*i);
        }
 
        return true;
    } else {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
        std::cerr << "\t\tLate bypass sched fail.: " << dst_.toString()
                  << std::endl;
#endif
        delete sched;
        undo();
        return false;
    }
}
 
 
void
BFLateBypass::undoOnlyMe() {
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\t\t\tUndoing late bypass: " << dst_.toString() << std::endl;
#endif
 
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\t\t\tReassigning move: " << dst_.toString() <<" to cycle: "
          << originalCycle_ << " bus: " << originalBus_->name() << std::endl;
    if (!canAssign(
            originalCycle_, dst_, originalBus_, NULL, NULL, prologBus_)) {
        std::cerr << "assign to original cycle fail, cycle: "
                  << originalCycle_ << " movenode: "
                  << dst_.toString() << std::endl;
        for (int unsigned i = 0; i < dst_.destinationOperationCount(); i++) {
            std::cerr << "\tDestination op: "
                      << dst_.destinationOperation(i).toString() << std::endl;
        }
        ddg().writeToDotFile("late_bypass_undo_fail.dot");
        assert(false);
    }
#endif
    assign(originalCycle_, dst_, originalBus_, NULL, NULL, prologBus_);
#ifdef DEBUG_BUBBLEFISH_SCHEDULER
    std::cerr << "\t\tReassigned move:" << dst_.toString() << std::endl;
#endif
}