changeset 5418:8650025672d3

Merge
author asaha
date Wed, 10 Sep 2014 15:31:55 -0700
parents 0b53273ef822 d638e49facb6
children 9b04c0f54507
files src/share/vm/classfile/verifier.cpp src/share/vm/classfile/verifier.hpp src/share/vm/opto/library_call.cpp src/share/vm/runtime/arguments.cpp
diffstat 16 files changed, 778 insertions(+), 39 deletions(-) [+]
line wrap: on
line diff
--- a/src/cpu/x86/vm/assembler_x86.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/cpu/x86/vm/assembler_x86.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -7641,10 +7641,12 @@
   // if fast computation is not possible, result is NaN. Requires
   // fallback from user of this macro.
   // increase precision for intermediate steps of the computation
+  BLOCK_COMMENT("fast_pow {");
   increase_precision();
   fyl2x();                 // Stack: (Y*log2(X)) ...
   pow_exp_core_encoding(); // Stack: exp(X) ...
   restore_precision();
+  BLOCK_COMMENT("} fast_pow");
 }
 
 void MacroAssembler::fast_exp() {
--- a/src/share/vm/classfile/stackMapFrame.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/classfile/stackMapFrame.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2014, 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
@@ -54,15 +54,19 @@
   return frame;
 }
 
-bool StackMapFrame::has_new_object() const {
+// Return true if frame has an uninitialized (new) object that differs
+// from the target frame's object.
+bool StackMapFrame::has_nonmatching_new_object(const StackMapFrame *target_frame) const {
   int32_t i;
   for (i = 0; i < _max_locals; i++) {
-    if (_locals[i].is_uninitialized()) {
+    if (_locals[i].is_uninitialized() &&
+        !_locals[i].equals(target_frame->_locals[i])) {
       return true;
     }
   }
   for (i = 0; i < _stack_size; i++) {
-    if (_stack[i].is_uninitialized()) {
+    if (_stack[i].is_uninitialized() &&
+        !_stack[i].equals(target_frame->_stack[i])) {
       return true;
     }
   }
--- a/src/share/vm/classfile/stackMapFrame.hpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/classfile/stackMapFrame.hpp	Wed Sep 10 15:31:55 2014 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2014, 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
@@ -155,8 +155,9 @@
     const methodHandle m, VerificationType thisKlass, TRAPS);
 
   // Search local variable type array and stack type array.
-  // Return true if an uninitialized object is found.
-  bool has_new_object() const;
+  // Return true if an uninitialized object is found that is
+  // not equal to the corresponding object on the target frame.
+  bool has_nonmatching_new_object(const StackMapFrame *target_frame) const;
 
   // Search local variable type array and stack type array.
   // Set every element with type of old_object to new_object.
--- a/src/share/vm/classfile/stackMapTable.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/classfile/stackMapTable.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -138,7 +138,10 @@
 
 void StackMapTable::check_new_object(
     const StackMapFrame* frame, int32_t target, TRAPS) const {
-  if (frame->offset() > target && frame->has_new_object()) {
+  int frame_index = get_index_from_offset(target);
+  assert(frame_index >= 0 && frame_index < _frame_count, "bad frame index");
+  if (frame->offset() > target &&
+      frame->has_nonmatching_new_object(_frame_array[frame_index])) {
     frame->verifier()->verify_error(
         ErrorContext::bad_code(frame->offset()),
         "Uninitialized object exists on backward branch %d", target);
--- a/src/share/vm/gc_implementation/g1/g1AllocRegion.hpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/gc_implementation/g1/g1AllocRegion.hpp	Wed Sep 10 15:31:55 2014 -0700
@@ -172,7 +172,7 @@
 
   // Should be called when we want to release the active region which
   // is returned after it's been retired.
-  HeapRegion* release();
+  virtual HeapRegion* release();
 
 #if G1_ALLOC_REGION_TRACING
   void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL);
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -6628,6 +6628,35 @@
   _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes,
                                GCAllocForTenured);
 }
+
+HeapRegion* OldGCAllocRegion::release() {
+  HeapRegion* cur = get();
+  if (cur != NULL) {
+    // Determine how far we are from the next card boundary. If it is smaller than
+    // the minimum object size we can allocate into, expand into the next card.
+    HeapWord* top = cur->top();
+    HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetSharedArray::N_bytes);
+
+    size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize);
+
+    if (to_allocate_words != 0) {
+      // We are not at a card boundary. Fill up, possibly into the next, taking the
+      // end of the region and the minimum object size into account.
+      to_allocate_words = MIN2(pointer_delta(cur->end(), cur->top(), HeapWordSize),
+                               MAX2(to_allocate_words, G1CollectedHeap::min_fill_size()));
+
+      // Skip allocation if there is not enough space to allocate even the smallest
+      // possible object. In this case this region will not be retained, so the
+      // original problem cannot occur.
+      if (to_allocate_words >= G1CollectedHeap::min_fill_size()) {
+        HeapWord* dummy = attempt_allocation(to_allocate_words, true /* bot_updates */);
+        CollectedHeap::fill_with_object(dummy, to_allocate_words);
+      }
+    }
+  }
+  return G1AllocRegion::release();
+}
+
 // Heap region set verification
 
 class VerifyRegionListsClosure : public HeapRegionClosure {
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Wed Sep 10 15:31:55 2014 -0700
@@ -183,6 +183,13 @@
 public:
   OldGCAllocRegion()
   : G1AllocRegion("Old GC Alloc Region", true /* bot_updates */) { }
+
+  // This specialization of release() makes sure that the last card that has been
+  // allocated into has been completely filled by a dummy object.
+  // This avoids races when remembered set scanning wants to update the BOT of the
+  // last card in the retained old gc alloc region, and allocation threads
+  // allocating into that card at the same time.
+  virtual HeapRegion* release();
 };
 
 // The G1 STW is alive closure.
--- a/src/share/vm/oops/objArrayOop.hpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/oops/objArrayOop.hpp	Wed Sep 10 15:31:55 2014 -0700
@@ -45,9 +45,10 @@
 private:
   // Give size of objArrayOop in HeapWords minus the header
   static int array_size(int length) {
-    const int OopsPerHeapWord = HeapWordSize/heapOopSize;
+    const uint OopsPerHeapWord = HeapWordSize/heapOopSize;
     assert(OopsPerHeapWord >= 1 && (HeapWordSize % heapOopSize == 0),
            "Else the following (new) computation would be in error");
+    uint res = ((uint)length + OopsPerHeapWord - 1)/OopsPerHeapWord;
 #ifdef ASSERT
     // The old code is left in for sanity-checking; it'll
     // go away pretty soon. XXX
@@ -55,16 +56,15 @@
     // oop->length() * HeapWordsPerOop;
     // With narrowOops, HeapWordsPerOop is 1/2 or equal 0 as an integer.
     // The oop elements are aligned up to wordSize
-    const int HeapWordsPerOop = heapOopSize/HeapWordSize;
-    int old_res;
+    const uint HeapWordsPerOop = heapOopSize/HeapWordSize;
+    uint old_res;
     if (HeapWordsPerOop > 0) {
       old_res = length * HeapWordsPerOop;
     } else {
-      old_res = align_size_up(length, OopsPerHeapWord)/OopsPerHeapWord;
+      old_res = align_size_up((uint)length, OopsPerHeapWord)/OopsPerHeapWord;
     }
+    assert(res == old_res, "Inconsistency between old and new.");
 #endif  // ASSERT
-    int res = ((uint)length + OopsPerHeapWord - 1)/OopsPerHeapWord;
-    assert(res == old_res, "Inconsistency between old and new.");
     return res;
   }
 
--- a/src/share/vm/opto/ifnode.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/opto/ifnode.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2014, 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
@@ -503,7 +503,7 @@
   jint  off = 0;
   if (l->is_top()) {
     return 0;
-  } else if (l->is_Add()) {
+  } else if (l->Opcode() == Op_AddI) {
     if ((off = l->in(1)->find_int_con(0)) != 0) {
       ind = l->in(2);
     } else if ((off = l->in(2)->find_int_con(0)) != 0) {
--- a/src/share/vm/opto/library_call.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/opto/library_call.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -201,7 +201,7 @@
   bool inline_math(vmIntrinsics::ID id);
   bool inline_exp();
   bool inline_pow();
-  void finish_pow_exp(Node* result, Node* x, Node* y, const TypeFunc* call_type, address funcAddr, const char* funcName);
+  Node* finish_pow_exp(Node* result, Node* x, Node* y, const TypeFunc* call_type, address funcAddr, const char* funcName);
   bool inline_min_max(vmIntrinsics::ID id);
   Node* generate_min_max(vmIntrinsics::ID id, Node* x, Node* y);
   // This returns Type::AnyPtr, RawPtr, or OopPtr.
@@ -1580,7 +1580,7 @@
   return true;
 }
 
-void LibraryCallKit::finish_pow_exp(Node* result, Node* x, Node* y, const TypeFunc* call_type, address funcAddr, const char* funcName) {
+Node* LibraryCallKit::finish_pow_exp(Node* result, Node* x, Node* y, const TypeFunc* call_type, address funcAddr, const char* funcName) {
   //-------------------
   //result=(result.isNaN())? funcAddr():result;
   // Check: If isNaN() by checking result!=result? then either trap
@@ -1596,7 +1596,7 @@
       uncommon_trap(Deoptimization::Reason_intrinsic,
                     Deoptimization::Action_make_not_entrant);
     }
-    set_result(result);
+    return result;
   } else {
     // If this inlining ever returned NaN in the past, we compile a call
     // to the runtime to properly handle corner cases
@@ -1626,9 +1626,10 @@
 
       result_region->init_req(2, control());
       result_val->init_req(2, value);
-      set_result(result_region, result_val);
+      set_control(_gvn.transform(result_region));
+      return _gvn.transform(result_val);
     } else {
-      set_result(result);
+      return result;
     }
   }
 }
@@ -1640,7 +1641,8 @@
   Node* arg = round_double_node(argument(0));
   Node* n   = _gvn.transform(new (C) ExpDNode(C, control(), arg));
 
-  finish_pow_exp(n, arg, NULL, OptoRuntime::Math_D_D_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::dexp), "EXP");
+  n = finish_pow_exp(n, arg, NULL, OptoRuntime::Math_D_D_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::dexp), "EXP");
+  set_result(n);
 
   C->set_has_split_ifs(true); // Has chance for split-if optimization
   return true;
@@ -1650,27 +1652,48 @@
 // Inline power instructions, if possible.
 bool LibraryCallKit::inline_pow() {
   // Pseudocode for pow
-  // if (x <= 0.0) {
-  //   long longy = (long)y;
-  //   if ((double)longy == y) { // if y is long
-  //     if (y + 1 == y) longy = 0; // huge number: even
-  //     result = ((1&longy) == 0)?-DPow(abs(x), y):DPow(abs(x), y);
+  // if (y == 2) {
+  //   return x * x;
+  // } else {
+  //   if (x <= 0.0) {
+  //     long longy = (long)y;
+  //     if ((double)longy == y) { // if y is long
+  //       if (y + 1 == y) longy = 0; // huge number: even
+  //       result = ((1&longy) == 0)?-DPow(abs(x), y):DPow(abs(x), y);
+  //     } else {
+  //       result = NaN;
+  //     }
   //   } else {
-  //     result = NaN;
+  //     result = DPow(x,y);
   //   }
-  // } else {
-  //   result = DPow(x,y);
+  //   if (result != result)?  {
+  //     result = uncommon_trap() or runtime_call();
+  //   }
+  //   return result;
   // }
-  // if (result != result)?  {
-  //   result = uncommon_trap() or runtime_call();
-  // }
-  // return result;
 
   Node* x = round_double_node(argument(0));
   Node* y = round_double_node(argument(2));
 
   Node* result = NULL;
 
+  Node*   const_two_node = makecon(TypeD::make(2.0));
+  Node*   cmp_node       = _gvn.transform(new (C) CmpDNode(y, const_two_node));
+  Node*   bool_node      = _gvn.transform(new (C) BoolNode(cmp_node, BoolTest::eq));
+  IfNode* if_node        = create_and_xform_if(control(), bool_node, PROB_STATIC_INFREQUENT, COUNT_UNKNOWN);
+  Node*   if_true        = _gvn.transform(new (C) IfTrueNode(if_node));
+  Node*   if_false       = _gvn.transform(new (C) IfFalseNode(if_node));
+
+  RegionNode* region_node = new (C) RegionNode(3);
+  region_node->init_req(1, if_true);
+
+  Node* phi_node = new (C) PhiNode(region_node, Type::DOUBLE);
+  // special case for x^y where y == 2, we can convert it to x * x
+  phi_node->init_req(1, _gvn.transform(new (C) MulDNode(x, x)));
+
+  // set control to if_false since we will now process the false branch
+  set_control(if_false);
+
   if (!too_many_traps(Deoptimization::Reason_intrinsic)) {
     // Short form: skip the fancy tests and just check for NaN result.
     result = _gvn.transform(new (C) PowDNode(C, control(), x, y));
@@ -1794,7 +1817,15 @@
     result = _gvn.transform(phi);
   }
 
-  finish_pow_exp(result, x, y, OptoRuntime::Math_DD_D_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::dpow), "POW");
+  result = finish_pow_exp(result, x, y, OptoRuntime::Math_DD_D_Type(), CAST_FROM_FN_PTR(address, SharedRuntime::dpow), "POW");
+
+  // control from finish_pow_exp is now input to the region node
+  region_node->set_req(2, control());
+  // the result from finish_pow_exp is now input to the phi node
+  phi_node->init_req(2, result);
+  set_control(_gvn.transform(region_node));
+  record_for_igvn(region_node);
+  set_result(_gvn.transform(phi_node));
 
   C->set_has_split_ifs(true); // Has chance for split-if optimization
   return true;
--- a/src/share/vm/opto/loopopts.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/opto/loopopts.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -2754,11 +2754,11 @@
       // Hit!  Refactor use to use the post-incremented tripcounter.
       // Compute a post-increment tripcounter.
       Node *opaq = new (C) Opaque2Node( C, cle->incr() );
-      register_new_node( opaq, u_ctrl );
+      register_new_node(opaq, exit);
       Node *neg_stride = _igvn.intcon(-cle->stride_con());
       set_ctrl(neg_stride, C->root());
       Node *post = new (C) AddINode( opaq, neg_stride);
-      register_new_node( post, u_ctrl );
+      register_new_node(post, exit);
       _igvn.rehash_node_delayed(use);
       for (uint j = 1; j < use->req(); j++) {
         if (use->in(j) == phi)
--- a/src/share/vm/runtime/arguments.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/runtime/arguments.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -2080,6 +2080,9 @@
                                      1, 100, "TLABWasteTargetPercent");
 
   status = status && verify_object_alignment();
+#ifdef COMPILER1
+  status = status && verify_min_value(ValueMapInitialSize, 1, "ValueMapInitialSize");
+#endif
 
 #ifdef SPARC
   if (UseConcMarkSweepGC || UseG1GC) {
--- a/src/share/vm/runtime/objectMonitor.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/runtime/objectMonitor.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -421,6 +421,15 @@
       jt->java_suspend_self();
     }
     Self->set_current_pending_monitor(NULL);
+
+    // We cleared the pending monitor info since we've just gotten past
+    // the enter-check-for-suspend dance and we now own the monitor free
+    // and clear, i.e., it is no longer pending. The ThreadBlockInVM
+    // destructor can go to a safepoint at the end of this block. If we
+    // do a thread dump during that safepoint, then this thread will show
+    // as having "-locked" the monitor, but the OS and java.lang.Thread
+    // states will still report that the thread is blocked trying to
+    // acquire it.
   }
 
   Atomic::dec_ptr(&_count);
--- a/src/share/vm/runtime/vframe.cpp	Fri Sep 05 11:11:13 2014 -0700
+++ b/src/share/vm/runtime/vframe.cpp	Wed Sep 10 15:31:55 2014 -0700
@@ -197,6 +197,7 @@
         continue;
       }
       if (monitor->owner() != NULL) {
+        // the monitor is associated with an object, i.e., it is locked
 
         // First, assume we have the monitor locked. If we haven't found an
         // owned monitor before and this is the first frame, then we need to
@@ -207,7 +208,11 @@
         if (!found_first_monitor && frame_count == 0) {
           markOop mark = monitor->owner()->mark();
           if (mark->has_monitor() &&
-              mark->monitor() == thread()->current_pending_monitor()) {
+              ( // we have marked ourself as pending on this monitor
+                mark->monitor() == thread()->current_pending_monitor() ||
+                // we are not the owner of this monitor
+                !mark->monitor()->is_entered(thread())
+              )) {
             lock_state = "waiting to lock";
           }
         }
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/compiler/loopopts/TestLogSum.java	Wed Sep 10 15:31:55 2014 -0700
@@ -0,0 +1,111 @@
+/*
+ * Copyright (c) 2014, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8046516
+ * @summary Segmentation fault in JVM (easily reproducible)
+ * @run main/othervm -XX:-TieredCompilation -Xbatch TestLogSum
+ * @author jackkamm@gmail.com
+ */
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+public class TestLogSum {
+  public static void main(String[] args) {
+    double sum;
+
+    for (int i = 0; i < 6; i++) {
+        for (int n = 2; n < 30; n++) {
+           for (int j = 1; j <= n; j++) {
+              for (int k = 1; k <= j; k++) {
+                // System.out.println(computeSum(k, j));
+                sum = computeSum(k, j);
+              }
+           }
+        }
+      }
+   }
+
+   private static Map<List<Integer>, Double> cache = new HashMap<List<Integer>, Double>();
+   public static double computeSum(int x, int y) {
+      List<Integer> key = Arrays.asList(new Integer[] {x, y});
+
+      if (!cache.containsKey(key)) {
+
+        // explicitly creating/updating a double[] array, instead of using the LogSumArray wrapper object, will prevent the error
+        LogSumArray toReturn = new LogSumArray(x);
+
+        // changing loop indices will prevent the error
+        // in particular, for(z=0; z<x-1; z++), and then using z+1 in place of z, will not produce error
+        for (int z = 1; z < x+1; z++) {
+           double logSummand = Math.log(z + x + y);
+           toReturn.addLogSummand(logSummand);
+        }
+
+        // returning the value here without cacheing it will prevent the segfault
+        cache.put(key, toReturn.retrieveLogSum());
+      }
+      return cache.get(key);
+   }
+
+   /*
+    * Given a bunch of logarithms log(X),log(Y),log(Z),...
+    * This class is used to compute the log of the sum, log(X+Y+Z+...)
+    */
+   private static class LogSumArray {
+      private double[] logSummandArray;
+      private int currSize;
+
+      private double maxLogSummand;
+
+      public LogSumArray(int maxEntries) {
+        this.logSummandArray = new double[maxEntries];
+
+        this.currSize = 0;
+        this.maxLogSummand = Double.NEGATIVE_INFINITY;
+      }
+
+      public void addLogSummand(double logSummand) {
+        logSummandArray[currSize] = logSummand;
+        currSize++;
+        // removing this line will prevent the error
+        maxLogSummand = Math.max(maxLogSummand, logSummand);
+      }
+
+      public double retrieveLogSum() {
+        if (maxLogSummand == Double.NEGATIVE_INFINITY) return Double.NEGATIVE_INFINITY;
+
+        assert currSize <= logSummandArray.length;
+
+        double factorSum = 0;
+        for (int i = 0; i < currSize; i++) {
+           factorSum += Math.exp(logSummandArray[i] - maxLogSummand);
+        }
+
+        return Math.log(factorSum) + maxLogSummand;
+      }
+   }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/runtime/Thread/TestThreadDumpMonitorContention.java	Wed Sep 10 15:31:55 2014 -0700
@@ -0,0 +1,534 @@
+/*
+ * Copyright (c) 2014, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug     8036823
+ * @bug     8046287
+ * @summary Creates two threads contending for the same lock and checks
+ *      whether jstack reports "locked" by more than one thread.
+ *
+ * @library /testlibrary
+ * @run main/othervm TestThreadDumpMonitorContention
+ */
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.lang.management.ManagementFactory;
+import java.lang.management.RuntimeMXBean;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import com.oracle.java.testlibrary.*;
+
+public class TestThreadDumpMonitorContention {
+    // jstack tends to be closely bound to the VM that we are running
+    // so use getTestJDKTool() instead of getCompileJDKTool() or even
+    // getJDKTool() which can fall back to "compile.jdk".
+    final static String JSTACK = JDKToolFinder.getTestJDKTool("jstack");
+    final static String PID = getPid();
+
+    // looking for header lines with these patterns:
+    // "ContendingThread-1" #19 prio=5 os_prio=64 tid=0x000000000079c000 nid=0x23 runnable [0xffff80ffb8b87000]
+    // "ContendingThread-2" #21 prio=5 os_prio=64 tid=0x0000000000780000 nid=0x2f waiting for monitor entry [0xfffffd7fc1111000]
+    // "ContendingThread-2" #24 prio=5 os_prio=64 tid=0x0000000000ec8800 nid=0x31 waiting on condition [0xfffffd7bbfffe000]
+    final static Pattern HEADER_PREFIX_PATTERN = Pattern.compile(
+        "^\"ContendingThread-.*");
+    final static Pattern HEADER_WAITING_PATTERN1 = Pattern.compile(
+        "^\"ContendingThread-.* waiting for monitor entry .*");
+    final static Pattern HEADER_WAITING_PATTERN2 = Pattern.compile(
+        "^\"ContendingThread-.* waiting on condition .*");
+    final static Pattern HEADER_RUNNABLE_PATTERN = Pattern.compile(
+        "^\"ContendingThread-.* runnable .*");
+
+    // looking for thread state lines with these patterns:
+    // java.lang.Thread.State: RUNNABLE
+    // java.lang.Thread.State: BLOCKED (on object monitor)
+    final static Pattern THREAD_STATE_PREFIX_PATTERN = Pattern.compile(
+        " *java\\.lang\\.Thread\\.State: .*");
+    final static Pattern THREAD_STATE_BLOCKED_PATTERN = Pattern.compile(
+        " *java\\.lang\\.Thread\\.State: BLOCKED \\(on object monitor\\)");
+    final static Pattern THREAD_STATE_RUNNABLE_PATTERN = Pattern.compile(
+        " *java\\.lang\\.Thread\\.State: RUNNABLE");
+
+    // looking for duplicates of this pattern:
+    // - locked <0x000000076ac59e20> (a TestThreadDumpMonitorContention$1)
+    final static Pattern LOCK_PATTERN = Pattern.compile(
+        ".* locked \\<.*\\(a TestThreadDumpMonitorContention.*");
+
+    // sanity checking header and thread state lines associated
+    // with this pattern:
+    // - waiting to lock <0x000000076ac59e20> (a TestThreadDumpMonitorContention$1)
+    final static Pattern WAITING_PATTERN = Pattern.compile(
+        ".* waiting to lock \\<.*\\(a TestThreadDumpMonitorContention.*");
+
+    final static Object barrier = new Object();
+    volatile static boolean done = false;
+
+    static int barrier_cnt = 0;
+    static int blank_line_match_cnt = 0;
+    static int error_cnt = 0;
+    static boolean have_header_line = false;
+    static boolean have_thread_state_line = false;
+    static String header_line = null;
+    static int header_prefix_match_cnt = 0;
+    static int locked_line_match_cnt = 0;
+    static String[] locked_match_list = new String[2];
+    static int n_samples = 15;
+    static int sum_both_running_cnt = 0;
+    static int sum_both_waiting_cnt = 0;
+    static int sum_contended_cnt = 0;
+    static int sum_locked_hdr_runnable_cnt = 0;
+    static int sum_locked_hdr_waiting1_cnt = 0;
+    static int sum_locked_hdr_waiting2_cnt = 0;
+    static int sum_locked_thr_state_blocked_cnt = 0;
+    static int sum_locked_thr_state_runnable_cnt = 0;
+    static int sum_one_waiting_cnt = 0;
+    static int sum_uncontended_cnt = 0;
+    static int sum_waiting_hdr_waiting1_cnt = 0;
+    static int sum_waiting_thr_state_blocked_cnt = 0;
+    static String thread_state_line = null;
+    static boolean verbose = false;
+    static int waiting_line_match_cnt = 0;
+
+    public static void main(String[] args) throws Exception {
+        if (args.length != 0) {
+            int arg_i = 0;
+            if (args[arg_i].equals("-v")) {
+                verbose = true;
+                arg_i++;
+            }
+
+            try {
+                n_samples = Integer.parseInt(args[arg_i]);
+            } catch (NumberFormatException nfe) {
+                System.err.println(nfe);
+                usage();
+            }
+        }
+
+        Runnable runnable = new Runnable() {
+            public void run() {
+                synchronized (barrier) {
+                    // let the main thread know we're running
+                    barrier_cnt++;
+                    barrier.notify();
+                }
+                while (!done) {
+                    synchronized (this) { }
+                }
+            }
+        };
+        Thread[] thread_list = new Thread[2];
+        thread_list[0] = new Thread(runnable, "ContendingThread-1");
+        thread_list[1] = new Thread(runnable, "ContendingThread-2");
+        synchronized (barrier) {
+            thread_list[0].start();
+            thread_list[1].start();
+
+            // Wait until the contending threads are running so that
+            // we don't sample any thread init states.
+            while (barrier_cnt < 2) {
+                barrier.wait();
+            }
+        }
+
+        doSamples();
+
+        done = true;
+
+        thread_list[0].join();
+        thread_list[1].join();
+
+        if (error_cnt == 0) {
+            System.out.println("Test PASSED.");
+        } else {
+            System.out.println("Test FAILED.");
+            throw new AssertionError("error_cnt=" + error_cnt);
+        }
+    }
+
+    // Reached a blank line which is the end of the
+    // stack trace without matching either LOCK_PATTERN
+    // or WAITING_PATTERN. Rare, but it's not an error.
+    //
+    // Example:
+    // "ContendingThread-1" #21 prio=5 os_prio=64 tid=0x00000000007b9000 nid=0x2f runnable [0xfffffd7fc1111000]
+    //    java.lang.Thread.State: RUNNABLE
+    //         at TestThreadDumpMonitorContention$1.run(TestThreadDumpMonitorContention.java:140)
+    //         at java.lang.Thread.run(Thread.java:745)
+    //
+    static boolean checkBlankLine(String line) {
+        if (line.length() == 0) {
+            blank_line_match_cnt++;
+            have_header_line = false;
+            have_thread_state_line = false;
+            return true;
+        }
+
+        return false;
+    }
+
+    // Process the locked line here if we found one.
+    //
+    // Example 1:
+    // "ContendingThread-1" #21 prio=5 os_prio=64 tid=0x00000000007b9000 nid=0x2f runnable [0xfffffd7fc1111000]
+    //    java.lang.Thread.State: RUNNABLE
+    //         at TestThreadDumpMonitorContention$1.run(TestThreadDumpMonitorContention.java:140)
+    //         - locked <0xfffffd7e6a2912f8> (a TestThreadDumpMonitorContention$1)
+    //         at java.lang.Thread.run(Thread.java:745)
+    //
+    // Example 2:
+    // "ContendingThread-1" #21 prio=5 os_prio=64 tid=0x00000000007b9000 nid=0x2f waiting for monitor entry [0xfffffd7fc1111000]
+    //    java.lang.Thread.State: BLOCKED (on object monitor)
+    //         at TestThreadDumpMonitorContention$1.run(TestThreadDumpMonitorContention.java:140)
+    //         - locked <0xfffffd7e6a2912f8> (a TestThreadDumpMonitorContention$1)
+    //         at java.lang.Thread.run(Thread.java:745)
+    //
+    // Example 3:
+    // "ContendingThread-2" #24 prio=5 os_prio=64 tid=0x0000000000ec8800 nid=0x31 waiting on condition [0xfffffd7bbfffe000]
+    //    java.lang.Thread.State: RUNNABLE
+    //    JavaThread state: _thread_blocked
+    // Thread: 0x0000000000ec8800  [0x31] State: _at_safepoint _has_called_back 0 _at_poll_safepoint 0
+    //    JavaThread state: _thread_blocked
+    //         at TestThreadDumpMonitorContention$1.run(TestThreadDumpMonitorContention.java:140)
+    //         - locked <0xfffffd7e6d03eb28> (a TestThreadDumpMonitorContention$1)
+    //         at java.lang.Thread.run(Thread.java:745)
+    //
+    static boolean checkLockedLine(String line) {
+        Matcher matcher = LOCK_PATTERN.matcher(line);
+        if (matcher.matches()) {
+            if (verbose) {
+                System.out.println("locked_line='" + line + "'");
+            }
+            locked_match_list[locked_line_match_cnt] = new String(line);
+            locked_line_match_cnt++;
+
+            matcher = HEADER_RUNNABLE_PATTERN.matcher(header_line);
+            if (matcher.matches()) {
+                sum_locked_hdr_runnable_cnt++;
+            } else {
+                // It's strange, but a locked line can also
+                // match the HEADER_WAITING_PATTERN{1,2}.
+                matcher = HEADER_WAITING_PATTERN1.matcher(header_line);
+                if (matcher.matches()) {
+                    sum_locked_hdr_waiting1_cnt++;
+                } else {
+                    matcher = HEADER_WAITING_PATTERN2.matcher(header_line);
+                    if (matcher.matches()) {
+                        sum_locked_hdr_waiting2_cnt++;
+                    } else {
+                        System.err.println();
+                        System.err.println("ERROR: header line does " +
+                            "not match runnable or waiting patterns.");
+                        System.err.println("ERROR: header_line='" +
+                            header_line + "'");
+                        System.err.println("ERROR: locked_line='" + line +
+                            "'");
+                        error_cnt++;
+                    }
+                }
+            }
+
+            matcher = THREAD_STATE_RUNNABLE_PATTERN.matcher(thread_state_line);
+            if (matcher.matches()) {
+                sum_locked_thr_state_runnable_cnt++;
+            } else {
+                // It's strange, but a locked line can also
+                // match the THREAD_STATE_BLOCKED_PATTERN.
+                matcher = THREAD_STATE_BLOCKED_PATTERN.matcher(
+                              thread_state_line);
+                if (matcher.matches()) {
+                    sum_locked_thr_state_blocked_cnt++;
+                } else {
+                    System.err.println();
+                    System.err.println("ERROR: thread state line does not " +
+                        "match runnable or waiting patterns.");
+                    System.err.println("ERROR: " + "thread_state_line='" +
+                        thread_state_line + "'");
+                    System.err.println("ERROR: locked_line='" + line + "'");
+                    error_cnt++;
+                }
+            }
+
+            // Have everything we need from this thread stack
+            // that matches the LOCK_PATTERN.
+            have_header_line = false;
+            have_thread_state_line = false;
+            return true;
+        }
+
+        return false;
+    }
+
+    // Process the waiting line here if we found one.
+    //
+    // Example:
+    // "ContendingThread-2" #22 prio=5 os_prio=64 tid=0x00000000007b9800 nid=0x30 waiting for monitor entry [0xfffffd7fc1010000]
+    //    java.lang.Thread.State: BLOCKED (on object monitor)
+    //         at TestThreadDumpMonitorContention$1.run(TestThreadDumpMonitorContention.java:140)
+    //         - waiting to lock <0xfffffd7e6a2912f8> (a TestThreadDumpMonitorContention$1)
+    //         at java.lang.Thread.run(Thread.java:745)
+    //
+    static boolean checkWaitingLine(String line) {
+        Matcher matcher = WAITING_PATTERN.matcher(line);
+        if (matcher.matches()) {
+            waiting_line_match_cnt++;
+            if (verbose) {
+                System.out.println("waiting_line='" + line + "'");
+            }
+
+            matcher = HEADER_WAITING_PATTERN1.matcher(header_line);
+            if (matcher.matches()) {
+                sum_waiting_hdr_waiting1_cnt++;
+            } else {
+                System.err.println();
+                System.err.println("ERROR: header line does " +
+                    "not match a waiting pattern.");
+                System.err.println("ERROR: header_line='" + header_line + "'");
+                System.err.println("ERROR: waiting_line='" + line + "'");
+                error_cnt++;
+            }
+
+            matcher = THREAD_STATE_BLOCKED_PATTERN.matcher(thread_state_line);
+            if (matcher.matches()) {
+                sum_waiting_thr_state_blocked_cnt++;
+            } else {
+                System.err.println();
+                System.err.println("ERROR: thread state line " +
+                    "does not match a waiting pattern.");
+                System.err.println("ERROR: thread_state_line='" +
+                    thread_state_line + "'");
+                System.err.println("ERROR: waiting_line='" + line + "'");
+                error_cnt++;
+            }
+
+            // Have everything we need from this thread stack
+            // that matches the WAITING_PATTERN.
+            have_header_line = false;
+            have_thread_state_line = false;
+            return true;
+        }
+
+        return false;
+    }
+
+    static void doSamples() throws Exception {
+        for (int count = 0; count < n_samples; count++) {
+            blank_line_match_cnt = 0;
+            header_prefix_match_cnt = 0;
+            locked_line_match_cnt = 0;
+            waiting_line_match_cnt = 0;
+            // verbose mode or an error has a lot of output so add more space
+            if (verbose || error_cnt > 0) System.out.println();
+            System.out.println("Sample #" + count);
+
+            // We don't use the ProcessTools, OutputBuffer or
+            // OutputAnalyzer classes from the testlibrary because
+            // we have a complicated multi-line parse to perform
+            // on a narrow subset of the JSTACK output.
+            //
+            // - we only care about stack traces that match
+            //   HEADER_PREFIX_PATTERN; only two should match
+            // - we care about at most three lines from each stack trace
+            // - if both stack traces match LOCKED_PATTERN, then that's
+            //   a failure and we report it
+            // - for a stack trace that matches LOCKED_PATTERN, we verify:
+            //   - the header line matches HEADER_RUNNABLE_PATTERN
+            //     or HEADER_WAITING_PATTERN{1,2}
+            //   - the thread state line matches THREAD_STATE_BLOCKED_PATTERN
+            //     or THREAD_STATE_RUNNABLE_PATTERN
+            //   - we report any mismatches as failures
+            // - for a stack trace that matches WAITING_PATTERN, we verify:
+            //   - the header line matches HEADER_WAITING_PATTERN1
+            //   - the thread state line matches THREAD_STATE_BLOCKED_PATTERN
+            //   - we report any mismatches as failures
+            // - the stack traces that match HEADER_PREFIX_PATTERN may
+            //   not match either LOCKED_PATTERN or WAITING_PATTERN
+            //   because we might observe the thread outside of
+            //   monitor operations; this is not considered a failure
+            //
+            // When we do observe LOCKED_PATTERN or WAITING_PATTERN,
+            // then we are checking the header and thread state patterns
+            // that occurred earlier in the current stack trace that
+            // matched HEADER_PREFIX_PATTERN. We don't use data from
+            // stack traces that don't match HEADER_PREFIX_PATTERN and
+            // we don't mix data between the two stack traces that do
+            // match HEADER_PREFIX_PATTERN.
+            //
+            Process process = new ProcessBuilder(JSTACK, PID)
+                .redirectErrorStream(true).start();
+
+            BufferedReader reader = new BufferedReader(new InputStreamReader(
+                                        process.getInputStream()));
+            String line;
+            while ((line = reader.readLine()) != null) {
+                Matcher matcher = null;
+
+                // process the header line here
+                if (!have_header_line) {
+                    matcher = HEADER_PREFIX_PATTERN.matcher(line);
+                    if (matcher.matches()) {
+                        header_prefix_match_cnt++;
+                        if (verbose) {
+                            System.out.println();
+                            System.out.println("header='" + line + "'");
+                        }
+                        header_line = new String(line);
+                        have_header_line = true;
+                        continue;
+                    }
+                    continue;  // skip until have a header line
+                }
+
+                // process the thread state line here
+                if (!have_thread_state_line) {
+                    matcher = THREAD_STATE_PREFIX_PATTERN.matcher(line);
+                    if (matcher.matches()) {
+                        if (verbose) {
+                            System.out.println("thread_state='" + line + "'");
+                        }
+                        thread_state_line = new String(line);
+                        have_thread_state_line = true;
+                        continue;
+                    }
+                    continue;  // skip until we have a thread state line
+                }
+
+                // process the locked line here if we find one
+                if (checkLockedLine(line)) {
+                    continue;
+                }
+
+                // process the waiting line here if we find one
+                if (checkWaitingLine(line)) {
+                    continue;
+                }
+
+                // process the blank line here if we find one
+                if (checkBlankLine(line)) {
+                    continue;
+                }
+            }
+            process.waitFor();
+
+            if (header_prefix_match_cnt != 2) {
+                System.err.println();
+                System.err.println("ERROR: should match exactly two headers.");
+                System.err.println("ERROR: header_prefix_match_cnt=" +
+                    header_prefix_match_cnt);
+                error_cnt++;
+            }
+
+            if (locked_line_match_cnt == 2) {
+                if (locked_match_list[0].equals(locked_match_list[1])) {
+                    System.err.println();
+                    System.err.println("ERROR: matching lock lines:");
+                    System.err.println("ERROR: line[0]'" +
+                        locked_match_list[0] + "'");
+                    System.err.println("ERROR: line[1]'" +
+                        locked_match_list[1] + "'");
+                    error_cnt++;
+                }
+            }
+
+            if (locked_line_match_cnt == 1) {
+                // one thread has the lock
+                if (waiting_line_match_cnt == 1) {
+                    // and the other contended for it
+                    sum_contended_cnt++;
+                } else {
+                    // and the other is just running
+                    sum_uncontended_cnt++;
+                }
+            } else if (waiting_line_match_cnt == 1) {
+                // one thread is waiting
+                sum_one_waiting_cnt++;
+            } else if (waiting_line_match_cnt == 2) {
+                // both threads are waiting
+                sum_both_waiting_cnt++;
+            } else {
+                // both threads are running
+                sum_both_running_cnt++;
+            }
+
+            // slight delay between jstack launches
+            Thread.sleep(500);
+        }
+
+        if (error_cnt != 0) {
+            // skip summary info since there were errors
+            return;
+        }
+
+        System.out.println("INFO: Summary for all samples:");
+        System.out.println("INFO: both_running_cnt=" + sum_both_running_cnt);
+        System.out.println("INFO: both_waiting_cnt=" + sum_both_waiting_cnt);
+        System.out.println("INFO: contended_cnt=" + sum_contended_cnt);
+        System.out.println("INFO: one_waiting_cnt=" + sum_one_waiting_cnt);
+        System.out.println("INFO: uncontended_cnt=" + sum_uncontended_cnt);
+        System.out.println("INFO: locked_hdr_runnable_cnt=" +
+            sum_locked_hdr_runnable_cnt);
+        System.out.println("INFO: locked_hdr_waiting1_cnt=" +
+            sum_locked_hdr_waiting1_cnt);
+        System.out.println("INFO: locked_hdr_waiting2_cnt=" +
+            sum_locked_hdr_waiting2_cnt);
+        System.out.println("INFO: locked_thr_state_blocked_cnt=" +
+            sum_locked_thr_state_blocked_cnt);
+        System.out.println("INFO: locked_thr_state_runnable_cnt=" +
+            sum_locked_thr_state_runnable_cnt);
+        System.out.println("INFO: waiting_hdr_waiting1_cnt=" +
+            sum_waiting_hdr_waiting1_cnt);
+        System.out.println("INFO: waiting_thr_state_blocked_cnt=" +
+            sum_waiting_thr_state_blocked_cnt);
+
+        if (sum_contended_cnt == 0) {
+            System.err.println("WARNING: the primary scenario for 8036823" +
+                " has not been exercised by this test run.");
+        }
+    }
+
+    // This helper relies on RuntimeMXBean.getName() returning a string
+    // that looks like this: 5436@mt-haku
+    //
+    // The testlibrary has tryFindJvmPid(), but that uses a separate
+    // process which is much more expensive for finding out your own PID.
+    //
+    static String getPid() {
+        RuntimeMXBean runtimebean = ManagementFactory.getRuntimeMXBean();
+        String vmname = runtimebean.getName();
+        int i = vmname.indexOf('@');
+        if (i != -1) {
+            vmname = vmname.substring(0, i);
+        }
+        return vmname;
+    }
+
+    static void usage() {
+        System.err.println("Usage: " +
+            "java TestThreadDumpMonitorContention [-v] [n_samples]");
+        System.exit(1);
+    }
+}