*** old/src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotSpeculationLog.java	Thu Mar 28 11:24:13 2019
--- new/src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotSpeculationLog.java	Thu Mar 28 11:24:13 2019

*** 1,7 ****
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  /*
!  * Copyright (c) 2014, 2014, Oracle and/or its affiliates. All rights reserved.
!  * Copyright (c) 2014, 2019, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.

*** 20,119 ****
--- 20,361 ----
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package jdk.vm.ci.hotspot;
  
! import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
! import static jdk.vm.ci.hotspot.CompilerToVM.compilerToVM;
  
+ import java.util.ArrayList;
+ import java.util.Arrays;
+ import java.util.Formatter;
+ import java.util.List;
+ 
+ import jdk.vm.ci.code.BailoutException;
  import jdk.vm.ci.meta.JavaConstant;
  import jdk.vm.ci.meta.SpeculationLog;
  
+ /**
+  * Implements a {@link SpeculationLog} that can be used to:
+  * <ul>
+  * <li>Query failed speculations recorded in a native linked list of {@code FailedSpeculation}s (see
+  * methodData.hpp).</li>
+  * <li>Make speculations during compilation and record them in compiled code. This must only be done
+  * on compilation-local {@link HotSpotSpeculationLog} objects.</li>
+  * </ul>
+  *
+  * The choice of constructor determines whether the native failed speculations list is
+  * {@linkplain #managesFailedSpeculations() managed} by a {@link HotSpotSpeculationLog} object.
+  */
  public class HotSpotSpeculationLog implements SpeculationLog {
+ 
+     private static final byte[] NO_FLATTENED_SPECULATIONS = {};
+ 
+     /**
+      * Creates a speculation log that manages a failed speculation list. That is, when this object
+      * dies, the native resources of the list are freed.
+      *
+      * @see #managesFailedSpeculations()
+      * @see #getFailedSpeculationsAddress()
+      */
+     public HotSpotSpeculationLog() {
+         managesFailedSpeculations = true;
+     }
+ 
+     /**
+      * Creates a speculation log that reads from an externally managed failed speculation list. That
+      * is, the lifetime of the list is independent of this object.
+      *
+      * @param failedSpeculationsAddress an address in native memory at which the pointer to the
+      *            externally managed sailed speculation list resides
+      */
+     public HotSpotSpeculationLog(long failedSpeculationsAddress) {
+         if (failedSpeculationsAddress == 0) {
+             throw new IllegalArgumentException("failedSpeculationsAddress cannot be 0");
+         }
+         this.failedSpeculationsAddress = failedSpeculationsAddress;
+         managesFailedSpeculations = false;
+     }
+ 
+     /**
+      * Gets the address of the pointer to the native failed speculations list.
+      *
+      * @see #managesFailedSpeculations()
+      */
+     public long getFailedSpeculationsAddress() {
+         if (managesFailedSpeculations) {
+             synchronized (this) {
+                 if (failedSpeculationsAddress == 0L) {
+                     failedSpeculationsAddress = UnsafeAccess.UNSAFE.allocateMemory(HotSpotJVMCIRuntime.getHostWordKind().getByteCount());
+                     UnsafeAccess.UNSAFE.putAddress(failedSpeculationsAddress, 0L);
+                     LogCleaner c = new LogCleaner(this, failedSpeculationsAddress);
+                     assert c.address == failedSpeculationsAddress;
+                 }
+             }
+         }
+         return failedSpeculationsAddress;
+     }
+ 
+     /**
+      * Adds {@code speculation} to the native list of failed speculations. To update this object's
+      * view of the failed speculations, {@link #collectFailedSpeculations()} must be called after
+      * this method returns.
+      *
+      * This method exists primarily for testing purposes. Speculations are normally only added to
+      * the list by HotSpot during deoptimization.
+      *
+      * @return {@code false} if the speculation could not be appended to the list
+      */
+     public boolean addFailedSpeculation(Speculation speculation) {
+         return compilerToVM().addFailedSpeculation(getFailedSpeculationsAddress(), ((HotSpotSpeculation) speculation).encoding);
+     }
+ 
+     /**
+      * Returns {@code true} if the value returned by {@link #getFailedSpeculationsAddress()} is only
+      * valid only as long as this object is alive, {@code false} otherwise.
+      */
+     public boolean managesFailedSpeculations() {
+         return managesFailedSpeculations;
+     }
+ 
      public static final class HotSpotSpeculation extends Speculation {
          private JavaConstant encoding;
  
          HotSpotSpeculation(SpeculationReason reason, JavaConstant encoding) {
+         /**
+          * A speculation id is a long encoding an offset (high 32 bits) and a length (low 32 bts).
+          * Combined, the index and length denote where the {@linkplain #encoding encoded
+          * speculation} is in a {@linkplain HotSpotSpeculationLog#getFlattenedSpeculations
+          * flattened} speculations array.
+          */
+         private final JavaConstant id;
+ 
+         private final byte[] encoding;
+ 
+         HotSpotSpeculation(SpeculationReason reason, JavaConstant id, byte[] encoding) {
              super(reason);
+             this.id = id;
              this.encoding = encoding;
          }
  
          public JavaConstant getEncoding() {
!             return encoding;
!             return id;
+         }
+ 
+         @Override
+         public String toString() {
+             long indexAndLength = id.asLong();
+             int index = decodeIndex(indexAndLength);
+             int length = decodeLength(indexAndLength);
+             return String.format("{0x%016x[index: %d, len: %d, hash: 0x%x]: %s}", indexAndLength, index, length, Arrays.hashCode(encoding), getReason());
          }
      }
  
      /** Written by the C++ code that performs deoptimization. */
      private volatile long lastFailed;
+     /**
+      * Address of a pointer to a set of failed speculations. The address is recorded in the nmethod
+      * compiled with this speculation log such that when it fails a speculation, the speculation is
+      * added to the list.
+      */
+     private long failedSpeculationsAddress;
  
      /** All speculations that have caused a deoptimization. */
      private Set<SpeculationReason> failedSpeculations;
+     private final boolean managesFailedSpeculations;
  
      /** Strong references to all reasons embedded in the current nmethod. */
      private HashMap<SpeculationReason, JavaConstant> speculations;
+     /**
+      * The list of failed speculations read from native memory via
+      * {@link CompilerToVM#getFailedSpeculations}.
+      */
+     private byte[][] failedSpeculations;
  
      private long currentSpeculationID;
+     /**
+      * Speculations made during the compilation associated with this log.
+      */
+     private List<byte[]> speculations;
+     private List<SpeculationReason> speculationReasons;
  
      @Override
-     public synchronized void collectFailedSpeculations() {
!         if (lastFailed != 0) {
              if (failedSpeculations == null) {
!                 failedSpeculations = new HashSet<>(2);
!         if (failedSpeculationsAddress != 0 && UnsafeAccess.UNSAFE.getLong(failedSpeculationsAddress) != 0) {
+             failedSpeculations = compilerToVM().getFailedSpeculations(failedSpeculationsAddress, failedSpeculations);
!             assert failedSpeculations.getClass() == byte[][].class;
          }
              if (speculations != null) {
                  SpeculationReason lastFailedSpeculation = lookupSpeculation(this.lastFailed);
                  if (lastFailedSpeculation != null) {
                      failedSpeculations.add(lastFailedSpeculation);
      }
                  lastFailed = 0;
                  speculations = null;
+ 
+     byte[] getFlattenedSpeculations(boolean validate) {
+         if (speculations == null) {
+             return NO_FLATTENED_SPECULATIONS;
+         }
+         if (validate) {
+             int newFailuresStart = failedSpeculations == null ? 0 : failedSpeculations.length;
+             collectFailedSpeculations();
+             if (failedSpeculations != null && failedSpeculations.length != newFailuresStart) {
+                 for (SpeculationReason reason : speculationReasons) {
+                     byte[] encoding = encode(reason);
+                     // Only check against new failures
+                     if (contains(failedSpeculations, newFailuresStart, encoding)) {
+                         throw new BailoutException(false, "Speculation failed: " + reason);
                      }
                  }
              }
  
      private SpeculationReason lookupSpeculation(long value) {
          for (Map.Entry<SpeculationReason, JavaConstant> entry : speculations.entrySet()) {
              if (value == entry.getValue().asLong()) {
                  return entry.getKey();
          }
+         int size = 0;
+         for (byte[] s : speculations) {
+             size += s.length;
          }
!         return null;
!         byte[] result = new byte[size];
+         size = 0;
+         for (byte[] s : speculations) {
+             System.arraycopy(s, 0, result, size, s.length);
+             size += s.length;
+         }
+         return result;
      }
  
      @Override
-     public synchronized boolean maySpeculate(SpeculationReason reason) {
!         if (failedSpeculations != null && failedSpeculations.contains(reason)) {
!             return false;
!         if (failedSpeculations == null) {
!             collectFailedSpeculations();
+         }
+         if (failedSpeculations != null && failedSpeculations.length != 0) {
+             byte[] encoding = encode(reason);
+             return !contains(failedSpeculations, 0, encoding);
+         }
+         return true;
      }
+ 
+     /**
+      * @return {@code true} if {@code needle} is in {@code haystack[fromIndex..haystack.length-1]}
+      */
+     private static boolean contains(byte[][] haystack, int fromIndex, byte[] needle) {
+         for (int i = fromIndex; i < haystack.length; i++) {
+             byte[] fs = haystack[i];
+ 
+             if (Arrays.equals(fs, needle)) {
                  return true;
              }
+         }
+         return false;
+     }
+ 
+     private static long encodeIndexAndLength(int index, int length) {
+         return ((long) index) << 32 | length;
+     }
+ 
+     private static int decodeIndex(long indexAndLength) {
+         return (int) (indexAndLength >>> 32);
+     }
+ 
+     private static int decodeLength(long indexAndLength) {
+         return (int) indexAndLength & 0xFFFFFFFF;
+     }
  
      @Override
-     public synchronized Speculation speculate(SpeculationReason reason) {
+         byte[] encoding = encode(reason);
+         JavaConstant id;
          if (speculations == null) {
!             speculations = new HashMap<>();
!             speculations = new ArrayList<>();
+             speculationReasons = new ArrayList<>();
+             id = JavaConstant.forLong(encodeIndexAndLength(0, encoding.length));
+             speculations.add(encoding);
+             speculationReasons.add(reason);
+         } else {
+             id = null;
+             int flattenedIndex = 0;
+             for (byte[] fs : speculations) {
+                 if (Arrays.equals(fs, encoding)) {
+                     id = JavaConstant.forLong(encodeIndexAndLength(flattenedIndex, fs.length));
+                     break;
+                 }
+                 flattenedIndex += fs.length;
              }
          JavaConstant id = speculations.get(reason);
              if (id == null) {
!             id = JavaConstant.forLong(++currentSpeculationID);
!             speculations.put(reason, id);
!                 id = JavaConstant.forLong(encodeIndexAndLength(flattenedIndex, encoding.length));
!                 speculations.add(encoding);
+                 speculationReasons.add(reason);
              }
          return new HotSpotSpeculation(reason, id);
+         }
+ 
+         return new HotSpotSpeculation(reason, id, encoding);
+     }
+ 
+     private static byte[] encode(SpeculationReason reason) {
+         HotSpotSpeculationEncoding encoding = (HotSpotSpeculationEncoding) reason.encode(HotSpotSpeculationEncoding::new);
+         byte[] result = encoding == null ? null : encoding.getByteArray();
+         if (result == null) {
+             throw new IllegalArgumentException(HotSpotSpeculationLog.class.getName() + " expects " + reason.getClass().getName() + ".encode() to return a non-empty encoding");
+         }
+         return result;
      }
  
      @Override
-     public synchronized boolean hasSpeculations() {
-         return speculations != null && !speculations.isEmpty();
      }
  
      @Override
-     public synchronized Speculation lookupSpeculation(JavaConstant constant) {
          if (constant.isDefaultForKind()) {
              return NO_SPECULATION;
          }
!         SpeculationReason reason = lookupSpeculation(constant.asLong());
!         assert reason != null : "Speculation should have been registered";
          return new HotSpotSpeculation(reason, constant);
!         int flattenedIndex = decodeIndex(constant.asLong());
!         int index = 0;
+         for (byte[] s : speculations) {
+             if (flattenedIndex == 0) {
+                 SpeculationReason reason = speculationReasons.get(index);
+                 return new HotSpotSpeculation(reason, constant, s);
+             }
+             index++;
+             flattenedIndex -= s.length;
+         }
+         throw new IllegalArgumentException("Unknown encoded speculation: " + constant);
+     }
+ 
+     @Override
+     public String toString() {
+         Formatter buf = new Formatter();
+         buf.format("{managed:%s, failedSpeculationsAddress:0x%x, failedSpeculations:[", managesFailedSpeculations, failedSpeculationsAddress);
+ 
+         String sep = "";
+         if (failedSpeculations != null) {
+             for (int i = 0; i < failedSpeculations.length; i++) {
+                 buf.format("%s{len:%d, hash:0x%x}", sep, failedSpeculations[i].length, Arrays.hashCode(failedSpeculations[i]));
+                 sep = ", ";
+             }
+         }
+ 
+         buf.format("], speculations:[");
+ 
+         int size = 0;
+         if (speculations != null) {
+             sep = "";
+             for (int i = 0; i < speculations.size(); i++) {
+                 byte[] s = speculations.get(i);
+                 size += s.length;
+                 buf.format("%s{len:%d, hash:0x%x, reason:{%s}}", sep, s.length, Arrays.hashCode(s), speculationReasons.get(i));
+                 sep = ", ";
+             }
+         }
+         buf.format("], len:%d, hash:0x%x}", size, Arrays.hashCode(getFlattenedSpeculations(false)));
+         return buf.toString();
+     }
+ 
+     /**
+      * Frees the native memory resources associated with {@link HotSpotSpeculationLog}s once they
+      * become reclaimable.
+      */
+     private static final class LogCleaner extends Cleaner {
+ 
+         LogCleaner(HotSpotSpeculationLog referent, long address) {
+             super(referent);
+             this.address = address;
+         }
+ 
+         @Override
+         void doCleanup() {
+             long pointer = UnsafeAccess.UNSAFE.getAddress(address);
+             if (pointer != 0) {
+                 compilerToVM().releaseFailedSpeculations(address);
+             }
+             UnsafeAccess.UNSAFE.freeMemory(address);
+         }
+ 
+         final long address;
      }
  }
+