/**
   * Insert the list of <code>newPasses</code> into <code>passes</code> immediately after the pass
   * named <code>id</code>.
   */
  public void afterPass(List passes, Pass.ID id, List newPasses) {
    for (ListIterator i = passes.listIterator(); i.hasNext(); ) {
      Pass p = (Pass) i.next();

      if (p.id() == id) {
        for (Iterator j = newPasses.iterator(); j.hasNext(); ) {
          i.add(j.next());
        }

        return;
      }
    }

    throw new InternalCompilerError("Pass " + id + " not found.");
  }
  /** Remove the pass named <code>id</code> from <code>passes</code>. */
  public void removePass(List passes, Pass.ID id) {
    for (ListIterator i = passes.listIterator(); i.hasNext(); ) {
      Pass p = (Pass) i.next();

      if (p.id() == id) {
        if (p instanceof BarrierPass) {
          throw new InternalCompilerError("Cannot remove a barrier pass.");
        }

        i.remove();
        return;
      }
    }

    throw new InternalCompilerError("Pass " + id + " not found.");
  }
  /**
   * Insert the list of <code>newPasses</code> into <code>passes</code> immediately before the pass
   * named <code>id</code>.
   */
  public void beforePass(List passes, Pass.ID id, List newPasses) {
    for (ListIterator i = passes.listIterator(); i.hasNext(); ) {
      Pass p = (Pass) i.next();

      if (p.id() == id) {
        // Backup one position.
        i.previous();

        for (Iterator j = newPasses.iterator(); j.hasNext(); ) {
          i.add(j.next());
        }

        return;
      }
    }

    throw new InternalCompilerError("Pass " + id + " not found.");
  }
  /**
   * Get the sub-list of passes for the job between passes <code>begin</code> and <code>end</code>,
   * inclusive.
   */
  public List passes(Job job, Pass.ID begin, Pass.ID end) {
    List l = passes(job);
    Pass p = null;

    Iterator i = l.iterator();

    while (i.hasNext()) {
      p = (Pass) i.next();
      if (begin == p.id()) break;
      if (!(p instanceof BarrierPass)) i.remove();
    }

    while (p.id() != end && i.hasNext()) {
      p = (Pass) i.next();
    }

    while (i.hasNext()) {
      p = (Pass) i.next();
      i.remove();
    }

    return l;
  }
  /**
   * Before running <code>Pass pass</code> on <code>SourceJob job</code> make sure that all
   * appropriate scheduling invariants are satisfied, to ensure that all passes of other jobs that
   * <code>job</code> depends on will have already been done.
   */
  protected void enforceInvariants(Job job, Pass pass) throws CyclicDependencyException {
    SourceJob srcJob = job.sourceJob();
    if (srcJob == null) {
      return;
    }

    BarrierPass lastBarrier = srcJob.lastBarrier();
    if (lastBarrier != null) {
      // make sure that _all_ dependent jobs have completed at least up to
      // the last barrier (not just children).
      //
      // Ideally the invariant should be that only the source jobs that
      // job _depends on_ should be brought up to the last barrier.
      // This is work to be done in the future...
      List allDependentSrcs = new ArrayList(srcJob.dependencies());
      Iterator i = allDependentSrcs.iterator();
      while (i.hasNext()) {
        Source s = (Source) i.next();
        Object o = jobs.get(s);
        if (o == COMPLETED_JOB) continue;
        if (o == null) {
          throw new InternalCompilerError("Unknown source " + s);
        }
        SourceJob sj = (SourceJob) o;
        if (sj.pending(lastBarrier.id())) {
          // Make the job run up to the last barrier.
          // We ignore the return result, since even if the job
          // fails, we will keep on going and see
          // how far we get...
          if (Report.should_report(Report.frontend, 3)) {
            Report.report(3, "Running " + sj + " to " + lastBarrier.id() + " for " + srcJob);
          }
          runToPass(sj, lastBarrier.id());
        }
      }
    }

    if (pass instanceof GlobalBarrierPass) {
      // need to make sure that _all_ jobs have completed just up to
      // this global barrier.

      // If we hit a cyclic dependency, ignore it and run the other
      // jobs up to that pass.  Then try again to run the cyclic
      // pass.  If we hit the cycle again for the same job, stop.
      LinkedList barrierWorklist = new LinkedList(jobs.values());

      while (!barrierWorklist.isEmpty()) {
        Object o = barrierWorklist.removeFirst();
        if (o == COMPLETED_JOB) continue;
        SourceJob sj = (SourceJob) o;
        if (sj.completed(pass.id()) || sj.nextPass() == sj.passByID(pass.id())) {
          // the source job has either done this global pass
          // (which is possible if the job was loaded late in the
          // game), or is right up to the global barrier.
          continue;
        }

        // Make the job run up to just before the global barrier.
        // We ignore the return result, since even if the job
        // fails, we will keep on going and see
        // how far we get...
        Pass beforeGlobal = sj.getPreviousTo(pass.id());
        if (Report.should_report(Report.frontend, 3)) {
          Report.report(3, "Running " + sj + " to " + beforeGlobal.id() + " for " + srcJob);
        }

        // Don't use runToPass, since that catches the
        // CyclicDependencyException that we should report
        // back to the caller.
        while (!sj.pendingPasses().isEmpty()) {
          Pass p = (Pass) sj.pendingPasses().get(0);

          runPass(sj, p);

          if (p == beforeGlobal) {
            break;
          }
        }
      }
    }
  }
  /**
   * Run the pass <code>pass</code> on the job. Before running the pass on the job, if the job is a
   * <code>SourceJob</code>, then this method will ensure that the scheduling invariants are
   * enforced by calling <code>enforceInvariants</code>.
   */
  protected void runPass(Job job, Pass pass) throws CyclicDependencyException {
    // make sure that all scheduling invariants are satisfied before running
    // the next pass. We may thus execute some other passes on other
    // jobs running the given pass.
    try {
      enforceInvariants(job, pass);
    } catch (CyclicDependencyException e) {
      // A job that depends on this job is still running
      // an earlier pass.  We cannot continue this pass,
      // but we can just silently fail since the job we're
      // that depends on this one will eventually try
      // to run this pass again when it reaches a barrier.
      return;
    }

    if (getOptions().disable_passes.contains(pass.name())) {
      if (Report.should_report(Report.frontend, 1)) Report.report(1, "Skipping pass " + pass);
      job.finishPass(pass, true);
      return;
    }

    if (Report.should_report(Report.frontend, 1))
      Report.report(1, "Trying to run pass " + pass + " in " + job);

    if (job.isRunning()) {
      // We're currently running.  We can't reach the goal.
      throw new CyclicDependencyException(job + " cannot reach pass " + pass);
    }

    pass.resetTimers();

    boolean result = false;
    if (job.status()) {
      Job oldCurrentJob = this.currentJob;
      this.currentJob = job;
      Report.should_report.push(pass.name());

      // Stop the timer on the old pass. */
      Pass oldPass = oldCurrentJob != null ? oldCurrentJob.runningPass() : null;

      if (oldPass != null) {
        oldPass.toggleTimers(true);
      }

      job.setRunningPass(pass);
      pass.toggleTimers(false);

      result = pass.run();

      pass.toggleTimers(false);
      job.setRunningPass(null);

      Report.should_report.pop();
      this.currentJob = oldCurrentJob;

      // Restart the timer on the old pass. */
      if (oldPass != null) {
        oldPass.toggleTimers(true);
      }

      // pretty-print this pass if we need to.
      if (getOptions().print_ast.contains(pass.name())) {
        System.err.println("--------------------------------" + "--------------------------------");
        System.err.println("Pretty-printing AST for " + job + " after " + pass.name());

        PrettyPrinter pp = new PrettyPrinter();
        pp.printAst(job.ast(), new CodeWriter(System.err, 78));
      }

      // dump this pass if we need to.
      if (getOptions().dump_ast.contains(pass.name())) {
        System.err.println("--------------------------------" + "--------------------------------");
        System.err.println("Dumping AST for " + job + " after " + pass.name());

        NodeVisitor dumper = new DumpAst(new CodeWriter(System.err, 78));
        dumper = dumper.begin();
        job.ast().visit(dumper);
        dumper.finish();
      }

      // This seems to work around a VM bug on linux with JDK
      // 1.4.0.  The mark-sweep collector will sometimes crash.
      // Running the GC explicitly here makes the bug go away.
      // If this fails, maybe run with bigger heap.

      // System.gc();
    }

    Stats stats = getStats();
    stats.accumPassTimes(pass.id(), pass.inclusiveTime(), pass.exclusiveTime());

    if (Report.should_report(Report.time, 2)) {
      Report.report(
          2,
          "Finished "
              + pass
              + " status="
              + str(result)
              + " inclusive_time="
              + pass.inclusiveTime()
              + " exclusive_time="
              + pass.exclusiveTime());
    } else if (Report.should_report(Report.frontend, 1)) {
      Report.report(1, "Finished " + pass + " status=" + str(result));
    }

    job.finishPass(pass, result);
  }