org.apache.log4j.Logger#isTraceEnabled ( )源码实例Demo

private void placeRefcounts(Logger logger, GlobalVars globals, Function fn,
    Block block, RCTracker increments, Set<Var> parentAssignedAliasVars) {

  // First canonicalize so we can merge refcounts
  increments.canonicalize();

  if (logger.isTraceEnabled()) {
    logger.trace("");
    logger.trace("Adding increments for block " + block.getType() + " of " +
        fn.id());
    logger.trace("==============================");
    logger.trace(increments);
  }

  reorderContinuations(logger, block);

  // Move any increment instructions up to this block
  // if they can be combined with increments here
  pullUpRefIncrements(block, increments);

  placer.placeAll(logger, globals, fn, block, increments,
                  parentAssignedAliasVars);
}
 

/**
 * Prints out the configuration in sorted order.
 */
public static void printConfig(Configuration conf, Logger log) {
    if (log.isTraceEnabled()) {
        SortedSet<String> sortedKeys = new TreeSet<>();
        for (Map.Entry<String,String> e : conf) {
            sortedKeys.add(e.getKey());
        }
        for (String k : sortedKeys) {
            log.trace(k + "=" + conf.get(k));
        }
    }
}
 

public void closeConnection(Logger log) {
    
    if (log.isTraceEnabled()) {
        log.trace("closing connections for query " + getQueryId());
    }
    
    Connection connection = getConnection();
    Statement statement = getStatement();
    CachedRowSet crs = getCrs();
    resetConnection();
    DbUtils.closeQuietly(connection, statement, crs);
}
 

/**
 * @param comparable
 * @param methodReference
 * @return
 */
private boolean isImplied ( Logger cl, MethodReference comparable, MethodReference actual, MethodReference methodReference ) {
    Set<MethodReference> alreadyKnown = this.state.getAlreadyKnown(comparable);
    for ( MethodReference ref : alreadyKnown ) {
        if ( ref.implies(methodReference) ) {
            if ( cl.isTraceEnabled() ) {
                cl.trace(actual + " implied by " + methodReference); //$NON-NLS-1$
            }
            return true;
        }
    }

    return false;
}
 

private synchronized void forceLogLevels() {
	Logger bindLog = LogManager.getLogger(org.hibernate.type.descriptor.sql.BasicBinder.class);
	if(bindLog != null && !bindLog.isTraceEnabled()) {
		restoreBindLevel = bindLog.getLevel();
		restoreBind = true;
		bindLog.setLevel(Level.TRACE);
	}
	Logger sqlLog = LogManager.getLogger("org.hibernate.SQL");
	if(sqlLog != null && !sqlLog.isDebugEnabled()) {
		restoreSQLLevel = sqlLog.getLevel();
		restoreSQL = true;
		sqlLog.setLevel(Level.DEBUG);
	}
	Logger statLog = LogManager.getLogger(org.hibernate.stat.StatisticsImpl.class);
	if(statLog != null && !statLog.isInfoEnabled()) {
		restoreStatLevel = statLog.getLevel();
		restoreStat = true;
		statLog.setLevel(Level.INFO);
	}
	Logger loaderLog = LogManager.getLogger(org.hibernate.loader.Loader.class);
	if(loaderLog != null && !loaderLog.isTraceEnabled()) { // Trace for hydrated objects, Debug for result row
		restoreLoaderLevel = loaderLog.getLevel();
		restoreLoader = true;
		loaderLog.setLevel(Level.TRACE);
	}
	Logger jdbcLog = LogManager.getLogger(org.hibernate.jdbc.AbstractBatcher.class);
	if(jdbcLog != null && !jdbcLog.isDebugEnabled()) {
		restoreJdbcLevel = jdbcLog.getLevel();
		restoreJdbc = true;
		jdbcLog.setLevel(Level.DEBUG);
	}
}
 

/**
 * Return true if inst2 writes some of inst1's required vars
 *
 * TODO: the current approach can result in false positives, e.g.
 * alias instructions look like they're reading variable.
 * @param logger
 * @param inst1
 * @param inst1Inputs
 * @param inst2
 * @param inst2Inputs
 * @return
 */
private boolean writesInputs(Logger logger,
        StatementInfo info1,
        StatementInfo info2) {

  for (Instruction storeRef: info2.getByOpcode(Opcode.STORE_REF)) {
    assert(storeRef.op == Opcode.STORE_REF);
    if (info1.piecewiseAssigned.contains(storeRef.getOutput(0))) {
      // Special case for address_of: otherwise looks like they both write it
      if (logger.isTraceEnabled())
        logger.trace(info2 + " pieces " + info1);
      return true;
    }
  }

  // Check for initialization of outputs (inputs covered by other logic)
  if (initializesOutputs(info1, info2)) {
    if (logger.isTraceEnabled())
      logger.trace(info2 + " initializes output of " + info1);
    return true;
  }


  for (Var inst2Output: info2.modifiedOutputs) {
    if (info1.inputVars.contains(inst2Output)) {
      if (logger.isTraceEnabled())
        logger.trace(info2 + " modifies input of " + info1);
      return true;
    }
  }
  return false;
}
 

/**
 * Try to piggyback decrement operations on instructions or continuations
 * in block
 *
 * @param logger
 * @param fn
 * @param block
 * @param tracker
 * @param rcType
 */
private void piggybackOnStatements(Logger logger, Function fn,
    Block block, RCTracker tracker, RCDir dir, RefCountType rcType) {
  if (!RCUtil.piggybackEnabled()) {
    return;
  }

  // Initially all decrements are candidates for piggybacking
  RefCountCandidates candidates =
      tracker.getVarCandidates(block, rcType, dir);
  if (logger.isTraceEnabled()) {
    logger.trace("Piggyback candidates: " + candidates);
  }

  UseFinder subblockWalker = new UseFinder(tracker, rcType,
                                           candidates.varKeySet());

  // Depending on whether it's a decrement or an increment, we need
  // to traverse statements in a different direciton so that refcounts
  // can be disqualified in the right order
  boolean reverse = (dir == RCDir.DECR);

  if (reverse) {
    piggybackOnContinuations(logger, fn, block, tracker, dir, rcType,
                             candidates, subblockWalker, reverse);
  }

  piggybackOnStatements(logger, fn, block, tracker, dir, rcType, candidates,
                        subblockWalker, reverse);

  if (!reverse) {
    piggybackOnContinuations(logger, fn, block, tracker, dir, rcType,
                             candidates, subblockWalker, reverse);
  }
}
 

private static void updateCongruent(Logger logger, GlobalConstants consts,
          Function function, Instruction inst, int stmtIndex,
          Congruences state) throws OptUnsafeError {
  List<ValLoc> resVals = inst.getResults();
  List<Alias> aliases = inst.getAliases();

  if (logger.isTraceEnabled()) {
    logger.trace("resVals: " + resVals);
    logger.trace("aliases: " + aliases);
  }
  state.update(consts, function.id().uniqueName(), resVals, aliases,
               stmtIndex);
}
 

public static void trace(Logger logger, String messageFormat,Object...args){
	if(logger.isTraceEnabled())logger.trace(String.format(messageFormat,args));
}
 

/**
 * Attempt to explode individual instruction
 * @param logger
 * @param fn
 * @param execCx
 * @param block
 * @param it
 * @param inst
 * @param waitedFor any vars waited for, e.g. in outer exploded.  This prevents
 *      infinite cycles of exploding if we didn't change instruction
 * @return true if exploded
 */
private static boolean tryExplode(Logger logger, Function fn,
      ExecContext execCx, Block block, ListIterator<Statement> it,
      Instruction inst, HierarchicalSet<Var> waitedFor) {
  MakeImmRequest req = inst.canMakeImmediate(waitedFor,
           Collections.<ArgCV>emptySet(), Collections.<Var>emptySet(),
           true);
  if (req != null && req.in.size() > 0) {
    if (logger.isTraceEnabled()) {
      logger.trace("Exploding " + inst + " in function " + fn.id());
    }
    
    // Remove old instruction now that we're certain to replace it
    it.remove();
    
    List<Pair<Var, Ternary>> waitVars = new ArrayList<Pair<Var, Ternary>>();
    Map<Var, Var> filenameMap = new HashMap<Var, Var>();
    OptUtil.buildWaitVars(block, it, req.in, req.out, filenameMap, waitVars);
    
    Block insideWaitBlock = enterWaits(fn, execCx, block, inst, req, waitVars);
    
    // Instructions to add inside wait
    List<Statement> instBuffer = new ArrayList<Statement>();
    
    // Fetch the inputs
    List<Arg> inVals = OptUtil.fetchMakeImmInputs(insideWaitBlock, req.in,
                                                  instBuffer);
          
    // Create local instruction, copy out outputs
    List<Var> localOutputs = OptUtil.createMakeImmOutputs(insideWaitBlock,
                                        req.out, filenameMap, instBuffer); 

    MakeImmChange change = inst.makeImmediate(
                                new OptVarCreator(insideWaitBlock),
                                Fetched.makeList(req.out, localOutputs, true),
                                Fetched.makeList(req.in, inVals, false));
    OptUtil.fixupImmChange(fn.id(), block, insideWaitBlock, inst,
               change, instBuffer, localOutputs, req.out);
    
    // Remove old instruction, add new one inside wait block
    insideWaitBlock.addStatements(instBuffer);
    return true;
  }
  return false;
}
 

/**
 * Assuming that branches are exhaustive, work out the set of variables
 * closed after the conditional has executed.
 *
 * @param state
 * @param branchStates
 * @return
 * @throws OptUnsafeError
 */
public static UnifiedValues unify(Logger logger, GlobalConstants consts,
               Function fn, boolean reorderingAllowed, int parentStmtIndex,
               Congruences state, Continuation cont,
               List<Congruences> branchStates, List<Block> branchBlocks)
                   throws OptUnsafeError {
  if (logger.isTraceEnabled()) {
    logger.trace("Unifying state from " + branchBlocks.size() +
                 " branches with continuation type " + cont.getType());
    for (int i = 0; i < branchBlocks.size(); i++) {
      logger.trace("Branch " + (i + 1) + " type was " +
                  branchBlocks.get(i).getType());
    }
  }
  if (branchStates.isEmpty()) {
    return EMPTY;
  } else {
    Set<Var> closed = new HashSet<Var>();
    Set<Var> recClosed = new HashSet<Var>();
    unifyClosed(branchStates, closed, recClosed, parentStmtIndex);

    List<ValLoc> availVals = new ArrayList<ValLoc>();
    List<ArgCV> allUnifiedCVs = new ArrayList<ArgCV>();

    // Track which sets of args from each branch are mapped into a
    // unified var
    Map<List<Arg>, Var> unifiedVars = new HashMap<List<Arg>, Var>();
    int iter = 1;
    boolean newCVs;
    do {
      if (logger.isTraceEnabled()) {
        logger.trace("Start iteration " + iter + " of unification");
      }
      newCVs = false;

      for (CongruenceType congType: Arrays.asList(CongruenceType.VALUE,
                                                  CongruenceType.ALIAS)) {

        List<ArgCV> newAllBranchCVs = findAllBranchCVs(state, congType,
                                          branchStates, allUnifiedCVs);

        Pair<List<ValLoc>, Boolean> result = unifyCVs(consts, fn,
                reorderingAllowed, cont.parent(), parentStmtIndex, congType,
                branchStates, branchBlocks, newAllBranchCVs, unifiedVars);
        availVals.addAll(result.val1);
        if (result.val2) {
          newCVs = true;
        }

        allUnifiedCVs.addAll(newAllBranchCVs);
        if (logger.isTraceEnabled()) {
          logger.trace("Finish iteration " + iter + " of unification for "
                     + congType + " New CVs: " + result.val1);
        }
      }

      if (iter >= MAX_UNIFY_ITERATIONS) {
        logger.debug("Exceeded max unify iterations.");
        if (logger.isTraceEnabled()) {
          logger.trace(cont); // Dump IR for inspection
        }
        break;
      }
      iter++;
    } while (newCVs);

    return new UnifiedValues(closed, recClosed, availVals);
  }
}
 

private void structBuildRec(Logger logger, Block block) {
  // Track all assigned struct paths
  ListMultimap<Var, List<String>> assignedPaths = ArrayListMultimap.create();

  // Find all struct assign statements in block
  for (Statement stmt: block.getStatements()) {
    if (stmt.type() == StatementType.INSTRUCTION) {
      Instruction inst = stmt.instruction();
      if (inst.op == Opcode.STRUCT_STORE_SUB) {
        Var struct = inst.getOutput(0);
        List<Arg> inputs = inst.getInputs();
        List<Arg> fields = inputs.subList(1, inputs.size());
        assignedPaths.put(struct, Arg.extractStrings(fields));
      }
    }
  }

  // Check if all fields were assigned
  for (Var candidate: assignedPaths.keySet()) {
    StructType candidateType = (StructType)candidate.type().getImplType();
    Set<List<String>> expectedPaths = allAssignablePaths(candidateType);
    List<List<String>> assigned = assignedPaths.get(candidate);

    logger.trace("Check candidate " + candidate.name() + "\n" +
                 "expected: " + expectedPaths + "\n" +
                 "assigned: " + assigned);

    for (List<String> path: assigned) {
      Type fieldType;
      try {
        fieldType = candidateType.fieldTypeByPath(path);
      } catch (TypeMismatchException e) {
        throw new STCRuntimeError(e.getMessage());
      }

      Set<List<String>> assignedSubPaths;
      if (Types.isStruct(fieldType)) {
        // Handle case where we assign a substruct
        StructType structFieldType = (StructType)fieldType.getImplType();
        assignedSubPaths = allAssignablePaths(structFieldType, path);
      } else {
        assignedSubPaths = Collections.singleton(path);
      }

      for (List<String> assignedPath: assignedSubPaths) {
        boolean found = expectedPaths.remove(assignedPath);
        if (!found) {
          logger.warn("Invalid or double-assigned struct field: " +
                       candidate.name() + "." + assignedPath);
        }
      }
    }
    if (expectedPaths.isEmpty()) {
      doStructBuildTransform(logger, block, candidate, assigned.size());
    } else if (logger.isTraceEnabled()) {
      logger.trace("Fields not assigned: " + expectedPaths);
    }
  }

  for (Continuation cont: block.allComplexStatements()) {
    for (Block cb: cont.getBlocks()) {
      structBuildRec(logger, cb);
    }
  }
}
 

private void piggybackOnStatements(Logger logger, Function fn, Block block,
    RCTracker tracker, RCDir dir, RefCountType rcType,
    RefCountCandidates candidates, UseFinder subblockWalker, boolean reverse) {
  // Vars where we were successful
  List<VarCount> successful = new ArrayList<VarCount>();

  // scan up from bottom of block instructions to see if we can piggyback
  ListIterator<Statement> it = reverse ? block.statementEndIterator()
                                        : block.statementIterator();
  while ((reverse && it.hasPrevious()) || (!reverse && it.hasNext())) {
    Statement stmt;
    if (reverse) {
      stmt = it.previous();
    } else {
      stmt = it.next();
    }

    switch (stmt.type()) {
      case INSTRUCTION: {
        Instruction inst = stmt.instruction();

        if (logger.isTraceEnabled()) {
          logger.trace("Try piggyback " + dir + " on " + inst);
        }

        VarCount piggybacked;
        do {
          /* Process one at a time so that candidates is correctly updated
           * for each call based on previous changes */
          piggybacked = inst.tryPiggyback(candidates, rcType);

          if (piggybacked != null && piggybacked.count != 0) {
            if (logger.isTraceEnabled()) {
              logger.trace("Piggybacked decr " + piggybacked + " on " + inst);
            }

            candidates.add(piggybacked.var, -piggybacked.count);
            successful.add(piggybacked);
          }
        } while (piggybacked != null && piggybacked.count != 0);

        // Make sure we don't modify before a use of the var by removing
        // from candidate set
        List<Var> used = findUses(inst, tracker, rcType,
                                  candidates.varKeySet());
        removeCandidates(used, tracker, candidates);
        break;
      }
      case CONDITIONAL:
        // Walk continuation to find usages
        subblockWalker.reset();
        TreeWalk.walkSyncChildren(logger, fn, stmt.conditional(), subblockWalker);
        removeCandidates(subblockWalker.getUsedVars(), tracker, candidates);
        break;
      default:
        throw new STCRuntimeError("Unknown statement type " + stmt.type());
    }
  }

  if (logger.isTraceEnabled()) {
    logger.trace(successful);
  }
  // Update main increments map
  for (VarCount vc: successful) {
    assert(vc != null);
    tracker.cancel(tracker.getRefCountVar(vc.var), rcType, -vc.count);
  }
}
 

private void optRecurseOnBlock(Logger logger, Function f, Block block,
    ArrayInfo info, InitState init,
    HierarchicalSet<Var> cands, HierarchicalSet<Var> invalid) {
  addBlockCandidates(f, block, info, cands);

  for (Var cand: cands) {
    if (!invalid.contains(cand)) {
      AliasTracker blockAliases = info.getAliases(block);
      AliasKey candKey = blockAliases.getCanonical(cand);

      BlockVarInfo vi = info.getEntry(block, cand);
      if (logger.isTraceEnabled()) {
        logger.trace("Candidate: " + cand + " in block " +
                System.identityHashCode(block) + " " + block.getType());
        logger.trace(vi);
      }
      if (vi.otherModRec) {
        logger.trace("Can't optimize due to other inserts!");
        invalid.add(cand);
      } else if ((vi.insertImmOnce && vi.insertImmHere) ||
                  (vi.noInserts() && vi.declaredHere)) {
        // Criteria 1: declared here && no inserts here or in children
        // TODO
        // Criteria 2: declared in ancestor && not modified on any
        //        non-mutually-exclusive path

        // Optimize here: cases where only inserted in this block,
        // or no inserts at all
        logger.trace("Can optimize!");
        replaceInserts(logger, block, blockAliases, init, cand, candKey);
        invalid.add(cand); // Don't try to opt in descendants
      } else if (vi.insertImmOnce) {
        logger.trace("Try to optimize in descendant block!");
        // Do nothing: handle in child block
      } else {
        logger.trace("Optimization not valid!");
        // Invalid: can't do optimization anywhere
        invalid.add(cand);
      }
    }
  }

  for (Statement stmt: block.getStatements()) {
    switch (stmt.type()) {
      case INSTRUCTION:
        // Update which variables are initialized
        InitVariables.updateInitVars(logger, stmt, init, false);
        break;
      case CONDITIONAL:
        // Recurse and optimize, plus also update init vars
        optRecurseOnCont(logger, f, stmt.conditional(), info, init,
                         cands, invalid);
        break;
    }
  }

  for (Continuation cont: block.getContinuations()) {
    optRecurseOnCont(logger, f, cont, info, init, cands, invalid);
  }
}
 

/**
 * Try to push down waits from current block into child blocks
 * @param logger
 * @param fn
 * @param block
 * @param currContext
 * @return
 */
private boolean pushDownWaits(Logger logger, Program prog, Function fn,
                              Block block, ExecContext currContext) {
  SetMultimap<Var, InstOrCont> waitMap = buildWaiterMap(prog, block);

  if (logger.isTraceEnabled()) {
    logger.trace("waitMap keys: " + waitMap.keySet());
  }

  if (waitMap.isEmpty()) {
    // If waitMap is empty, can't push anything down, so just shortcircuit
    return false;
  }
  boolean changed = false;

  HashSet<Continuation> allPushedDown = new HashSet<Continuation>();
  ArrayList<Continuation> contCopy =
              new ArrayList<Continuation>(block.getContinuations());
  for (Continuation c: contCopy) {
    if (allPushedDown.contains(c)) {
      // Was moved
      continue;
    }
    ExecContext newContext = canPushDownInto(c, currContext);
    if (newContext != null) {
      for (Block innerBlock: c.getBlocks()) {
        StackLite<Continuation> ancestors =
                                      new StackLite<Continuation>();
        ancestors.push(c);
        PushDownResult pdRes =
             pushDownWaitsRec(logger, fn, block, currContext, ancestors,
                              innerBlock, newContext, waitMap);
         changed = changed || pdRes.anyChanges;
        /* The list of continuations might be modified as continuations are
         * pushed down - track which ones are relocated */
        allPushedDown.addAll(pdRes.relocated);
      }
    }
  }
  return changed;
}
 

/**
 *
 * @param logger
 * @param ancestorBlock the block the instructions are moved from
 * @param ancestors
 * @param currBlock the block they are moved too (a descendant of the prior
 *              block)
 * @param currContext
 * @param currBlockIt  all changes to instructions in curr block
 *    are made through this iterator, and it is rewound to the previous position
 *    before the function exits
 * @param waitMap map of variable names to instructions/continuations they block
 *                  on
 * @param writtenV
 * @return true if change made, list of moved continuations
 */
private Pair<Boolean, Set<Continuation>> relocateDependentInstructions(
    Logger logger,
    Block ancestorBlock, ExecContext ancestorContext,
    StackLite<Continuation> ancestors,
    Block currBlock, ExecContext currContext, ListIterator<Statement> currBlockIt,
    SetMultimap<Var, InstOrCont> waitMap, Var writtenV) {
  boolean changed = false;
  // Remove from outer block
  Set<InstOrCont> waits = waitMap.get(writtenV);
  Set<Instruction> movedI = new HashSet<Instruction>();
  Set<Continuation> movedC = new HashSet<Continuation>();
  // Rely on later forward Dataflow pass to remove
  // unneeded wait vars

  /*
   * NOTE: instructions/ continuations retain the same relative
   * order they were in in the original block, this should help
   * optimization pass
   */
  for (InstOrCont ic: waits) {
    if (logger.isTraceEnabled())
      logger.trace("Pushing down: " + ic.toString());
    boolean relocated;
    switch (ic.type()) {
      case CONTINUATION: {
        if (logger.isTraceEnabled())
          logger.trace("Relocating " + ic.continuation().getType());
        relocated = relocateContinuation(ancestors, currBlock,
            currContext, movedC, ic.continuation());

        break;
      }
      case INSTRUCTION:
        if (logger.isTraceEnabled())
          logger.trace("Relocating " + ic.instruction());
        relocated = relocateInstruction(ancestors, currContext,
            currBlock, currBlockIt, movedI, ic.instruction());
        break;
      default:
        throw new STCRuntimeError("how on earth did we get here...");
    }
    changed = changed || relocated;
  }
  // Remove instructions from old block
  ancestorBlock.removeContinuations(movedC);
  ancestorBlock.removeStatements(movedI);

  // Rewind iterator so that next instruction returned
  // will be the first one added
  ICUtil.rewindIterator(currBlockIt, movedI.size());

  // Rebuild wait map to reflect changes
  updateWaiterMap(waitMap, movedC, movedI);
  return Pair.create(changed, movedC);
}
 

public static void trace(Logger logger,String message){
	if(logger.isTraceEnabled())logger.trace(message);
}
 

private void piggybackOnContinuations(Logger logger, Function fn,
    Block block, RCTracker tracker, RCDir dir, RefCountType rcType,
    RefCountCandidates candidates, UseFinder subblockWalker, boolean reverse) {
  // Try to piggyback on continuations, starting at bottom up
  ListIterator<Continuation> cit = reverse ? block.continuationEndIterator()
                                            : block.continuationIterator();
  while ((reverse && cit.hasPrevious()) || (!reverse && cit.hasNext())) {
    Continuation cont;
    if (reverse) {
      cont = cit.previous();
    } else {
      cont = cit.next();
    }

    if (RCUtil.isAsyncForeachLoop(cont)) {
      AbstractForeachLoop loop = (AbstractForeachLoop) cont;

      VarCount piggybacked;
      do {
        /* Process one at a time so that candidates is correctly updated
         * for each call based on previous changes */
        piggybacked = loop.tryPiggyBack(candidates, rcType, dir);

        if (piggybacked != null) {
          if (logger.isTraceEnabled()) {
            logger.trace("Piggybacked on foreach: " + piggybacked + " " +
                   rcType + " " + piggybacked.count);
          }
          candidates.add(piggybacked.var, -piggybacked.count);
          tracker.cancel(tracker.getRefCountVar(piggybacked.var), rcType,
                         -piggybacked.count);
        }
      } while (piggybacked != null);
    }

    // Walk continuation to find usages
    subblockWalker.reset();
    TreeWalk.walkSyncChildren(logger, fn, cont, subblockWalker);
    removeCandidates(subblockWalker.getUsedVars(), tracker, candidates);
  }
}
 

/**
 * @param rootBlock
 * @return true if the block makes progress of the specified type
 */
public static boolean blockProgress(Block rootBlock, Category type) {
  Logger logger = Logging.getSTCLogger();
  StackLite<Block> stack = new StackLite<Block>();
  stack.push(rootBlock);
  while (!stack.isEmpty()) {
    Block block = stack.pop();
    
    for (Statement stmt: block.getStatements()) {
      if (stmt.type() == StatementType.INSTRUCTION) {
        Instruction i = stmt.instruction();
        if (type == Category.CHEAP) {
          if (!i.isCheap()) {
            if (logger.isTraceEnabled()) {
              logger.trace("non-cheap instruction found: " + i);
            }
            return false;
          }
        } else if (type == Category.CHEAP_WORKER) {
          if (!isCheapWorkerInst(i)) {
            if (logger.isTraceEnabled()) {
              logger.trace("non-cheap-worker instruction found: " + i);
            }
            return false;
          }
        } else {
          assert(type == Category.NON_PROGRESS);
          if (i.isProgressEnabling() || !i.isCheap()) {
            if (logger.isTraceEnabled()) {
              logger.trace("progress instruction found: " + i);
            }
            return false;
          }
        }
      }
    }
    
    for (Continuation c: block.allComplexStatements()) {
      if (!c.isAsync()) {
        for (Block inner: c.getBlocks()) {
          stack.push(inner);
        }
      }
    }
  }
  return true;
}
 

/**
 *
 * @param logger
 * @param fn
 * @param block
 * @param cv
 * @param inst
 * @param insts
 *          if instructions inserted, leaves iterator pointing at previous
 *          instruction
 * @return
 */
private boolean switchToImmediate(Logger logger, Function fn,
    ExecContext execCx, Block block, Congruences state,
    Instruction inst, ListIterator<Statement> stmts, int stmtIndex) {
  if (!finalizedVarEnabled) {
    return false;
  }

  // First see if we can replace some futures with values
  MakeImmRequest req = inst.canMakeImmediate(state.getClosed(stmtIndex),
                             state.getClosedLocs(stmtIndex),
                             state.retrieveResultAvail(), false);

  if (req == null) {
    return false;
  }

  // Create replacement sequence
  Block insertContext;
  ListIterator<Statement> insertPoint;
  boolean waitRequired = req.mode.isDispatched() ||
           !req.mode.targetContextMatches(execCx);

  // First remove old instruction
  stmts.remove();

  if (!waitRequired) {
    insertContext = block;
    insertPoint = stmts;
  } else {
    WaitStatement wait = new WaitStatement(fn.id() + "-"
        + inst.shortOpName(), WaitVar.NONE, PassedVar.NONE, Var.NONE,
        WaitMode.TASK_DISPATCH, false, req.mode, inst.getTaskProps());
    insertContext = wait.getBlock();
    block.addContinuation(wait);
    // Insert at start of block
    insertPoint = insertContext.statementIterator();
  }

  // Now load the values
  List<Statement> alt = new ArrayList<Statement>();
  List<Fetched<Arg>> inVals = fetchInputsForSwitch(state, req,
                                  insertContext, !waitRequired, alt);
  if (logger.isTraceEnabled()) {
    logger.trace("Fetched " + inVals + " for " + inst
               + " req.in: " + req.in);
  }

  // Need filenames for output file values
  Map<Var, Var> filenameVals = loadOutputFileNames(state, stmtIndex,
              req.out, insertContext, insertPoint);


  List<Var> outFetched = OptUtil.createLocalOpOutputVars(insertContext,
              insertPoint, req.out, filenameVals);
  state.varDeclarations(outFetched);

  MakeImmChange change;
  change = inst.makeImmediate(new OptVarCreator(block),
        Fetched.makeList(req.out, outFetched, true), inVals);
  OptUtil.fixupImmChange(fn.id(), block, insertContext, inst, change, alt,
                         outFetched, req.out);

  if (logger.isTraceEnabled()) {
    logger.trace("Replacing instruction <" + inst + "> with sequence "
        + alt.toString());
  }

  // Add new instructions at insert point
  for (Statement newStmt : alt) {
    insertPoint.add(newStmt);
  }

  // Rewind argument iterator to instruction before replaced one
  if (stmts == insertPoint) {
    ICUtil.rewindIterator(stmts, alt.size());
  }
  return true;
}