*** old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/alloc/BiDirectionalTraceBuilder.java	Fri Jul  7 09:29:25 2017
--- new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/alloc/BiDirectionalTraceBuilder.java	Fri Jul  7 09:29:25 2017

*** 29,49 ****
--- 29,49 ----
  import java.util.Collection;
  import java.util.Deque;
  
  import org.graalvm.compiler.core.common.alloc.TraceBuilderResult.TrivialTracePredicate;
  import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
! import org.graalvm.compiler.debug.DebugContext;
  import org.graalvm.compiler.debug.Indent;
  
  /**
   * Computes traces by selecting the unhandled block with the highest execution frequency and going
   * in both directions, up and down, as long as possible.
   */
  public final class BiDirectionalTraceBuilder {
  
!     public static TraceBuilderResult computeTraces(DebugContext debug, AbstractBlockBase<?> startBlock, AbstractBlockBase<?>[] blocks, TrivialTracePredicate pred) {
!         return new BiDirectionalTraceBuilder(blocks).build(startBlock, blocks, pred);
!         return new BiDirectionalTraceBuilder(blocks).build(debug, startBlock, blocks, pred);
      }
  
      private final Deque<AbstractBlockBase<?>> worklist;
      private final BitSet processed;
      private final Trace[] blockToTrace;

*** 67,92 ****
--- 67,92 ----
      private boolean processed(AbstractBlockBase<?> b) {
          return processed.get(b.getId());
      }
  
      @SuppressWarnings("try")
!     private TraceBuilderResult build(DebugContext debug, AbstractBlockBase<?> startBlock, AbstractBlockBase<?>[] blocks, TrivialTracePredicate pred) {
!         try (Indent indent = Debug.logAndIndent("BiDirectionalTraceBuilder: start trace building")) {
!             ArrayList<Trace> traces = buildTraces();
!         try (Indent indent = debug.logAndIndent("BiDirectionalTraceBuilder: start trace building")) {
!             ArrayList<Trace> traces = buildTraces(debug);
              assert traces.get(0).getBlocks()[0].equals(startBlock) : "The first traces always contains the start block";
!             return TraceBuilderResult.create(debug, blocks, traces, blockToTrace, pred);
          }
      }
  
!     protected ArrayList<Trace> buildTraces(DebugContext debug) {
          ArrayList<Trace> traces = new ArrayList<>();
          // process worklist
          while (!worklist.isEmpty()) {
              AbstractBlockBase<?> block = worklist.pollFirst();
              assert block != null;
              if (!processed(block)) {
!                 Trace trace = new Trace(startTrace(debug, block));
                  for (AbstractBlockBase<?> traceBlock : trace.getBlocks()) {
                      blockToTrace[traceBlock.getId()] = trace;
                  }
                  trace.setId(traces.size());
                  traces.add(trace);

*** 95,136 ****
--- 95,138 ----
          return traces;
      }
  
      /**
       * Build a new trace starting at {@code block}.
+      *
+      * @param debug
       */
      @SuppressWarnings("try")
!     private Collection<AbstractBlockBase<?>> startTrace(DebugContext debug, AbstractBlockBase<?> block) {
          ArrayDeque<AbstractBlockBase<?>> trace = new ArrayDeque<>();
!         try (Indent i = Debug.logAndIndent("StartTrace: %s", block)) {
!             try (Indent indentFront = Debug.logAndIndent("Head:")) {
!         try (Indent i = debug.logAndIndent("StartTrace: %s", block)) {
!             try (Indent indentFront = debug.logAndIndent("Head:")) {
                  for (AbstractBlockBase<?> currentBlock = block; currentBlock != null; currentBlock = selectPredecessor(currentBlock)) {
!                     addBlockToTrace(debug, currentBlock);
                      trace.addFirst(currentBlock);
                  }
              }
              /* Number head blocks. Can not do this in the loop as we go backwards. */
              int blockNr = 0;
              for (AbstractBlockBase<?> b : trace) {
                  b.setLinearScanNumber(blockNr++);
              }
  
!             try (Indent indentBack = Debug.logAndIndent("Tail:")) {
!             try (Indent indentBack = debug.logAndIndent("Tail:")) {
                  for (AbstractBlockBase<?> currentBlock = selectSuccessor(block); currentBlock != null; currentBlock = selectSuccessor(currentBlock)) {
!                     addBlockToTrace(debug, currentBlock);
                      trace.addLast(currentBlock);
                      /* This time we can number the blocks immediately as we go forwards. */
                      currentBlock.setLinearScanNumber(blockNr++);
                  }
              }
          }
!         Debug.log("Trace: %s", trace);
!         debug.log("Trace: %s", trace);
          return trace;
      }
  
!     private void addBlockToTrace(DebugContext debug, AbstractBlockBase<?> currentBlock) {
!         Debug.log("add %s (prob: %f)", currentBlock, currentBlock.probability());
!         debug.log("add %s (prob: %f)", currentBlock, currentBlock.probability());
          processed.set(currentBlock.getId());
      }
  
      /**
       * @return The unprocessed predecessor with the highest probability, or {@code null}.