6902182: 4/4 Starting with jdwp agent should not incur performance penalty

Summary: Rename can_post_exceptions support to can_post_on_exceptions. Add support for should_post_on_exceptions flag to permit per JavaThread optimizations.
Reviewed-by: never, kvn, dcubed
Contributed-by: tom.deneau@amd.com

17 files changed, 107 insertions, 48 deletions

diff --git a/src/share/vm/c1/c1_LIRGenerator.cpp b/src/share/vm/c1/c1_LIRGenerator.cpp
index a39302879..05e479f26 100644
--- a/src/share/vm/c1/c1_LIRGenerator.cpp
+++ b/src/share/vm/c1/c1_LIRGenerator.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2005-2010 Sun Microsystems, Inc.  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
@@ -1765,7 +1765,7 @@ void LIRGenerator::do_Throw(Throw* x) {
     __ null_check(exception_opr, new CodeEmitInfo(info, true));
   }
 
-  if (compilation()->env()->jvmti_can_post_exceptions() &&
+  if (compilation()->env()->jvmti_can_post_on_exceptions() &&
       !block()->is_set(BlockBegin::default_exception_handler_flag)) {
     // we need to go through the exception lookup path to get JVMTI
     // notification done
diff --git a/src/share/vm/c1/c1_Runtime1.cpp b/src/share/vm/c1/c1_Runtime1.cpp
index 9093885ce..6c618cb8f 100644
--- a/src/share/vm/c1/c1_Runtime1.cpp
+++ b/src/share/vm/c1/c1_Runtime1.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1999-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1999-2010 Sun Microsystems, Inc.  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
@@ -110,8 +110,8 @@ static void deopt_caller() {
     RegisterMap reg_map(thread, false);
     frame runtime_frame = thread->last_frame();
     frame caller_frame = runtime_frame.sender(&reg_map);
-    VM_DeoptimizeFrame deopt(thread, caller_frame.id());
-    VMThread::execute(&deopt);
+    // bypass VM_DeoptimizeFrame and deoptimize the frame directly
+    Deoptimization::deoptimize_frame(thread, caller_frame.id());
     assert(caller_is_deopted(), "Must be deoptimized");
   }
 }
@@ -354,7 +354,7 @@ JRT_END
 
 
 JRT_ENTRY(void, Runtime1::post_jvmti_exception_throw(JavaThread* thread))
-  if (JvmtiExport::can_post_exceptions()) {
+  if (JvmtiExport::can_post_on_exceptions()) {
     vframeStream vfst(thread, true);
     address bcp = vfst.method()->bcp_from(vfst.bci());
     JvmtiExport::post_exception_throw(thread, vfst.method(), bcp, thread->exception_oop());
@@ -437,7 +437,7 @@ JRT_ENTRY_NO_ASYNC(static address, exception_handler_for_pc_helper(JavaThread* t
   bool guard_pages_enabled = thread->stack_yellow_zone_enabled();
   if (!guard_pages_enabled) guard_pages_enabled = thread->reguard_stack();
 
-  if (JvmtiExport::can_post_exceptions()) {
+  if (JvmtiExport::can_post_on_exceptions()) {
     // To ensure correct notification of exception catches and throws
     // we have to deoptimize here.  If we attempted to notify the
     // catches and throws during this exception lookup it's possible
diff --git a/src/share/vm/ci/ciEnv.cpp b/src/share/vm/ci/ciEnv.cpp
index e09c66a74..964ed249b 100644
--- a/src/share/vm/ci/ciEnv.cpp
+++ b/src/share/vm/ci/ciEnv.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1999-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1999-2010 Sun Microsystems, Inc.  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
@@ -178,7 +178,7 @@ void ciEnv::cache_jvmti_state() {
   _jvmti_can_hotswap_or_post_breakpoint = JvmtiExport::can_hotswap_or_post_breakpoint();
   _jvmti_can_examine_or_deopt_anywhere  = JvmtiExport::can_examine_or_deopt_anywhere();
   _jvmti_can_access_local_variables     = JvmtiExport::can_access_local_variables();
-  _jvmti_can_post_exceptions            = JvmtiExport::can_post_exceptions();
+  _jvmti_can_post_on_exceptions         = JvmtiExport::can_post_on_exceptions();
 }
 
 // ------------------------------------------------------------------
@@ -891,8 +891,8 @@ void ciEnv::register_method(ciMethod* target,
            JvmtiExport::can_examine_or_deopt_anywhere()) ||
           (!jvmti_can_access_local_variables() &&
            JvmtiExport::can_access_local_variables()) ||
-          (!jvmti_can_post_exceptions() &&
-           JvmtiExport::can_post_exceptions()) )) {
+          (!jvmti_can_post_on_exceptions() &&
+           JvmtiExport::can_post_on_exceptions()) )) {
       record_failure("Jvmti state change invalidated dependencies");
     }
 
diff --git a/src/share/vm/ci/ciEnv.hpp b/src/share/vm/ci/ciEnv.hpp
index 63b5ffe57..d20c1d1a3 100644
--- a/src/share/vm/ci/ciEnv.hpp
+++ b/src/share/vm/ci/ciEnv.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1999-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1999-2010 Sun Microsystems, Inc.  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
@@ -57,7 +57,7 @@ private:
   bool  _jvmti_can_hotswap_or_post_breakpoint;
   bool  _jvmti_can_examine_or_deopt_anywhere;
   bool  _jvmti_can_access_local_variables;
-  bool  _jvmti_can_post_exceptions;
+  bool  _jvmti_can_post_on_exceptions;
 
   // Cache DTrace flags
   bool  _dtrace_extended_probes;
@@ -259,7 +259,7 @@ public:
   bool  jvmti_can_hotswap_or_post_breakpoint() const { return _jvmti_can_hotswap_or_post_breakpoint; }
   bool  jvmti_can_examine_or_deopt_anywhere()  const { return _jvmti_can_examine_or_deopt_anywhere; }
   bool  jvmti_can_access_local_variables()     const { return _jvmti_can_access_local_variables; }
-  bool  jvmti_can_post_exceptions()            const { return _jvmti_can_post_exceptions; }
+  bool  jvmti_can_post_on_exceptions()         const { return _jvmti_can_post_on_exceptions; }
 
   // Cache DTrace flags
   void  cache_dtrace_flags();
diff --git a/src/share/vm/interpreter/interpreterRuntime.cpp b/src/share/vm/interpreter/interpreterRuntime.cpp
index bd9fc8d7c..78a6af554 100644
--- a/src/share/vm/interpreter/interpreterRuntime.cpp
+++ b/src/share/vm/interpreter/interpreterRuntime.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1997-2010 Sun Microsystems, Inc.  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
@@ -397,7 +397,7 @@ IRT_ENTRY(address, InterpreterRuntime::exception_handler_for_exception(JavaThrea
 
   // notify JVMTI of an exception throw; JVMTI will detect if this is a first
   // time throw or a stack unwinding throw and accordingly notify the debugger
-  if (JvmtiExport::can_post_exceptions()) {
+  if (JvmtiExport::can_post_on_exceptions()) {
     JvmtiExport::post_exception_throw(thread, h_method(), bcp(thread), h_exception());
   }
 
@@ -426,7 +426,7 @@ IRT_ENTRY(address, InterpreterRuntime::exception_handler_for_exception(JavaThrea
   }
   // notify debugger of an exception catch
   // (this is good for exceptions caught in native methods as well)
-  if (JvmtiExport::can_post_exceptions()) {
+  if (JvmtiExport::can_post_on_exceptions()) {
     JvmtiExport::notice_unwind_due_to_exception(thread, h_method(), handler_pc, h_exception(), (handler_pc != NULL));
   }
 
diff --git a/src/share/vm/opto/graphKit.cpp b/src/share/vm/opto/graphKit.cpp
index 57fea6480..d70fe1eef 100644
--- a/src/share/vm/opto/graphKit.cpp
+++ b/src/share/vm/opto/graphKit.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2001-2010 Sun Microsystems, Inc.  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
@@ -455,16 +455,44 @@ Bytecodes::Code GraphKit::java_bc() const {
     return Bytecodes::_illegal;
 }
 
+void GraphKit::uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
+                                                          bool must_throw) {
+    // if the exception capability is set, then we will generate code
+    // to check the JavaThread.should_post_on_exceptions flag to see
+    // if we actually need to report exception events (for this
+    // thread).  If we don't need to report exception events, we will
+    // take the normal fast path provided by add_exception_events.  If
+    // exception event reporting is enabled for this thread, we will
+    // take the uncommon_trap in the BuildCutout below.
+
+    // first must access the should_post_on_exceptions_flag in this thread's JavaThread
+    Node* jthread = _gvn.transform(new (C, 1) ThreadLocalNode());
+    Node* adr = basic_plus_adr(top(), jthread, in_bytes(JavaThread::should_post_on_exceptions_flag_offset()));
+    Node* should_post_flag = make_load(control(), adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw, false);
+
+    // Test the should_post_on_exceptions_flag vs. 0
+    Node* chk = _gvn.transform( new (C, 3) CmpINode(should_post_flag, intcon(0)) );
+    Node* tst = _gvn.transform( new (C, 2) BoolNode(chk, BoolTest::eq) );
+
+    // Branch to slow_path if should_post_on_exceptions_flag was true
+    { BuildCutout unless(this, tst, PROB_MAX);
+      // Do not try anything fancy if we're notifying the VM on every throw.
+      // Cf. case Bytecodes::_athrow in parse2.cpp.
+      uncommon_trap(reason, Deoptimization::Action_none,
+                    (ciKlass*)NULL, (char*)NULL, must_throw);
+    }
+
+}
+
 //------------------------------builtin_throw----------------------------------
 void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {
   bool must_throw = true;
 
-  if (env()->jvmti_can_post_exceptions()) {
-    // Do not try anything fancy if we're notifying the VM on every throw.
-    // Cf. case Bytecodes::_athrow in parse2.cpp.
-    uncommon_trap(reason, Deoptimization::Action_none,
-                  (ciKlass*)NULL, (char*)NULL, must_throw);
-    return;
+  if (env()->jvmti_can_post_on_exceptions()) {
+    // check if we must post exception events, take uncommon trap if so
+    uncommon_trap_if_should_post_on_exceptions(reason, must_throw);
+    // here if should_post_on_exceptions is false
+    // continue on with the normal codegen
   }
 
   // If this particular condition has not yet happened at this
diff --git a/src/share/vm/opto/graphKit.hpp b/src/share/vm/opto/graphKit.hpp
index 8135aca2d..b08c5859d 100644
--- a/src/share/vm/opto/graphKit.hpp
+++ b/src/share/vm/opto/graphKit.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2001-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2001-2010 Sun Microsystems, Inc.  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
@@ -251,6 +251,11 @@ class GraphKit : public Phase {
   // via an uncommon trap.
   void builtin_throw(Deoptimization::DeoptReason reason, Node* arg = NULL);
 
+  // Helper to check the JavaThread::_should_post_on_exceptions flag
+  // and branch to an uncommon_trap if it is true (with the specified reason and must_throw)
+  void uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
+                                                  bool must_throw) ;
+
   // Helper Functions for adding debug information
   void kill_dead_locals();
 #ifdef ASSERT
diff --git a/src/share/vm/opto/parse2.cpp b/src/share/vm/opto/parse2.cpp
index 869266c17..e0012681a 100644
--- a/src/share/vm/opto/parse2.cpp
+++ b/src/share/vm/opto/parse2.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1998-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1998-2010 Sun Microsystems, Inc.  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
@@ -2079,13 +2079,6 @@ void Parse::do_one_bytecode() {
     // null exception oop throws NULL pointer exception
     do_null_check(peek(), T_OBJECT);
     if (stopped())  return;
-    if (env()->jvmti_can_post_exceptions()) {
-      // "Full-speed throwing" is not necessary here,
-      // since we're notifying the VM on every throw.
-      uncommon_trap(Deoptimization::Reason_unhandled,
-                    Deoptimization::Action_none);
-      return;
-    }
     // Hook the thrown exception directly to subsequent handlers.
     if (BailoutToInterpreterForThrows) {
       // Keep method interpreted from now on.
@@ -2093,6 +2086,11 @@ void Parse::do_one_bytecode() {
                     Deoptimization::Action_make_not_compilable);
       return;
     }
+    if (env()->jvmti_can_post_on_exceptions()) {
+      // check if we must post exception events, take uncommon trap if so (with must_throw = false)
+      uncommon_trap_if_should_post_on_exceptions(Deoptimization::Reason_unhandled, false);
+    }
+    // Here if either can_post_on_exceptions or should_post_on_exceptions is false
     add_exception_state(make_exception_state(peek()));
     break;
 
diff --git a/src/share/vm/opto/runtime.cpp b/src/share/vm/opto/runtime.cpp
index f0d0c2170..2f39cfeb0 100644
--- a/src/share/vm/opto/runtime.cpp
+++ b/src/share/vm/opto/runtime.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1998-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1998-2010 Sun Microsystems, Inc.  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
@@ -810,7 +810,7 @@ JRT_ENTRY_NO_ASYNC(address, OptoRuntime::handle_exception_C_helper(JavaThread* t
     // we are switching to old paradigm: search for exception handler in caller_frame
     // instead in exception handler of caller_frame.sender()
 
-    if (JvmtiExport::can_post_exceptions()) {
+    if (JvmtiExport::can_post_on_exceptions()) {
       // "Full-speed catching" is not necessary here,
       // since we're notifying the VM on every catch.
       // Force deoptimization and the rest of the lookup
@@ -975,8 +975,8 @@ void OptoRuntime::deoptimize_caller_frame(JavaThread *thread, bool doit) {
     assert(stub_frame.is_runtime_frame() || exception_blob()->contains(stub_frame.pc()), "sanity check");
     frame caller_frame = stub_frame.sender(&reg_map);
 
-    VM_DeoptimizeFrame deopt(thread, caller_frame.id());
-    VMThread::execute(&deopt);
+    // bypass VM_DeoptimizeFrame and deoptimize the frame directly
+    Deoptimization::deoptimize_frame(thread, caller_frame.id());
   }
 }
 
diff --git a/src/share/vm/prims/jvmtiEventController.cpp b/src/share/vm/prims/jvmtiEventController.cpp
index 4e07d6f84..4eb2d5870 100644
--- a/src/share/vm/prims/jvmtiEventController.cpp
+++ b/src/share/vm/prims/jvmtiEventController.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2003-2010 Sun Microsystems, Inc.  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
@@ -82,7 +82,7 @@ static const jlong  EARLY_EVENT_BITS = CLASS_FILE_LOAD_HOOK_BIT |
                                THREAD_START_BIT | THREAD_END_BIT |
                                DYNAMIC_CODE_GENERATED_BIT;
 static const jlong  GLOBAL_EVENT_BITS = ~THREAD_FILTERED_EVENT_BITS;
-
+static const jlong  SHOULD_POST_ON_EXCEPTIONS_BITS = EXCEPTION_BITS | METHOD_EXIT_BIT | FRAME_POP_BIT;
 
 ///////////////////////////////////////////////////////////////
 //
@@ -511,7 +511,12 @@ JvmtiEventControllerPrivate::recompute_thread_enabled(JvmtiThreadState *state) {
         leave_interp_only_mode(state);
       }
     }
+
+    // update the JavaThread cached value for thread-specific should_post_on_exceptions value
+    bool should_post_on_exceptions = (any_env_enabled & SHOULD_POST_ON_EXCEPTIONS_BITS) != 0;
+    state->set_should_post_on_exceptions(should_post_on_exceptions);
   }
+
   return any_env_enabled;
 }
 
@@ -615,6 +620,10 @@ JvmtiEventControllerPrivate::recompute_enabled() {
 
     // set global truly enabled, that is, any thread in any environment
     JvmtiEventController::_universal_global_event_enabled.set_bits(any_env_thread_enabled);
+
+    // set global should_post_on_exceptions
+    JvmtiExport::set_should_post_on_exceptions((any_env_thread_enabled & SHOULD_POST_ON_EXCEPTIONS_BITS) != 0);
+
   }
 
   EC_TRACE(("JVMTI [-] # recompute enabled - after %llx", any_env_thread_enabled));
diff --git a/src/share/vm/prims/jvmtiExport.cpp b/src/share/vm/prims/jvmtiExport.cpp
index 7b2fffdbd..7d189e5be 100644
--- a/src/share/vm/prims/jvmtiExport.cpp
+++ b/src/share/vm/prims/jvmtiExport.cpp
@@ -877,7 +877,7 @@ void JvmtiExport::post_raw_breakpoint(JavaThread *thread, methodOop method, addr
 bool              JvmtiExport::_can_get_source_debug_extension            = false;
 bool              JvmtiExport::_can_maintain_original_method_order        = false;
 bool              JvmtiExport::_can_post_interpreter_events               = false;
-bool              JvmtiExport::_can_post_exceptions                       = false;
+bool              JvmtiExport::_can_post_on_exceptions                    = false;
 bool              JvmtiExport::_can_post_breakpoint                       = false;
 bool              JvmtiExport::_can_post_field_access                     = false;
 bool              JvmtiExport::_can_post_field_modification               = false;
@@ -908,6 +908,7 @@ bool              JvmtiExport::_should_post_garbage_collection_finish     = fals
 bool              JvmtiExport::_should_post_object_free                   = false;
 bool              JvmtiExport::_should_post_resource_exhausted            = false;
 bool              JvmtiExport::_should_post_vm_object_alloc               = false;
+bool              JvmtiExport::_should_post_on_exceptions                 = false;
 
 ////////////////////////////////////////////////////////////////////////////////////////////////
 
diff --git a/src/share/vm/prims/jvmtiExport.hpp b/src/share/vm/prims/jvmtiExport.hpp
index 20214aecf..a7e264ba7 100644
--- a/src/share/vm/prims/jvmtiExport.hpp
+++ b/src/share/vm/prims/jvmtiExport.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1998-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1998-2010 Sun Microsystems, Inc.  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
@@ -66,7 +66,7 @@ class JvmtiExport : public AllStatic {
   JVMTI_SUPPORT_FLAG(can_get_source_debug_extension)
   JVMTI_SUPPORT_FLAG(can_maintain_original_method_order)
   JVMTI_SUPPORT_FLAG(can_post_interpreter_events)
-  JVMTI_SUPPORT_FLAG(can_post_exceptions)
+  JVMTI_SUPPORT_FLAG(can_post_on_exceptions)
   JVMTI_SUPPORT_FLAG(can_post_breakpoint)
   JVMTI_SUPPORT_FLAG(can_post_field_access)
   JVMTI_SUPPORT_FLAG(can_post_field_modification)
@@ -93,6 +93,7 @@ class JvmtiExport : public AllStatic {
   JVMTI_SUPPORT_FLAG(should_post_data_dump)
   JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start)
   JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish)
+  JVMTI_SUPPORT_FLAG(should_post_on_exceptions)
 
   // ------ the below maybe don't have to be (but are for now)
   // fixed conditions here ------------
diff --git a/src/share/vm/prims/jvmtiManageCapabilities.cpp b/src/share/vm/prims/jvmtiManageCapabilities.cpp
index 82ddb4adf..195607346 100644
--- a/src/share/vm/prims/jvmtiManageCapabilities.cpp
+++ b/src/share/vm/prims/jvmtiManageCapabilities.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2003-2010 Sun Microsystems, Inc.  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
@@ -357,7 +357,7 @@ void JvmtiManageCapabilities::update() {
     avail.can_access_local_variables  ||
     avail.can_redefine_classes ||
     avail.can_retransform_classes);
-  JvmtiExport::set_can_post_exceptions(
+  JvmtiExport::set_can_post_on_exceptions(
     avail.can_generate_exception_events ||
     avail.can_generate_frame_pop_events ||
     avail.can_generate_method_exit_events);
diff --git a/src/share/vm/prims/jvmtiThreadState.hpp b/src/share/vm/prims/jvmtiThreadState.hpp
index d77d2a8a4..8103aa22a 100644
--- a/src/share/vm/prims/jvmtiThreadState.hpp
+++ b/src/share/vm/prims/jvmtiThreadState.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 2003-2010 Sun Microsystems, Inc.  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
@@ -381,6 +381,9 @@ class JvmtiThreadState : public CHeapObj {
   static ByteSize earlyret_value_offset() { return byte_offset_of(JvmtiThreadState, _earlyret_value); }
 
   void oops_do(OopClosure* f); // GC support
+
+public:
+  void set_should_post_on_exceptions(bool val) { _thread->set_should_post_on_exceptions_flag(val ? JNI_TRUE : JNI_FALSE); }
 };
 
 class RedefineVerifyMark : public StackObj {
diff --git a/src/share/vm/runtime/sharedRuntime.cpp b/src/share/vm/runtime/sharedRuntime.cpp
index bf100e714..a8b34a24b 100644
--- a/src/share/vm/runtime/sharedRuntime.cpp
+++ b/src/share/vm/runtime/sharedRuntime.cpp
@@ -364,7 +364,7 @@ oop SharedRuntime::retrieve_receiver( symbolHandle sig, frame caller ) {
 
 
 void SharedRuntime::throw_and_post_jvmti_exception(JavaThread *thread, Handle h_exception) {
-  if (JvmtiExport::can_post_exceptions()) {
+  if (JvmtiExport::can_post_on_exceptions()) {
     vframeStream vfst(thread, true);
     methodHandle method = methodHandle(thread, vfst.method());
     address bcp = method()->bcp_from(vfst.bci());
diff --git a/src/share/vm/runtime/thread.cpp b/src/share/vm/runtime/thread.cpp
index db90e0ef5..3bdf8dad0 100644
--- a/src/share/vm/runtime/thread.cpp
+++ b/src/share/vm/runtime/thread.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1997-2010 Sun Microsystems, Inc.  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
@@ -1173,6 +1173,7 @@ void JavaThread::initialize() {
   _exception_handler_pc = 0;
   _exception_stack_size = 0;
   _jvmti_thread_state= NULL;
+  _should_post_on_exceptions_flag = JNI_FALSE;
   _jvmti_get_loaded_classes_closure = NULL;
   _interp_only_mode    = 0;
   _special_runtime_exit_condition = _no_async_condition;
diff --git a/src/share/vm/runtime/thread.hpp b/src/share/vm/runtime/thread.hpp
index a06477bd2..49112fe23 100644
--- a/src/share/vm/runtime/thread.hpp
+++ b/src/share/vm/runtime/thread.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 1997-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * Copyright 1997-2010 Sun Microsystems, Inc.  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
@@ -1193,6 +1193,9 @@ class JavaThread: public Thread {
   static ByteSize suspend_flags_offset()         { return byte_offset_of(JavaThread, _suspend_flags       ); }
 
   static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
+  static ByteSize should_post_on_exceptions_flag_offset() {
+    return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
+  }
 
 #ifndef SERIALGC
   static ByteSize satb_mark_queue_offset()       { return byte_offset_of(JavaThread, _satb_mark_queue); }
@@ -1432,6 +1435,16 @@ public:
   void increment_interp_only_mode()         { ++_interp_only_mode; }
   void decrement_interp_only_mode()         { --_interp_only_mode; }
 
+  // support for cached flag that indicates whether exceptions need to be posted for this thread
+  // if this is false, we can avoid deoptimizing when events are thrown
+  // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
+ private:
+  int    _should_post_on_exceptions_flag;
+
+ public:
+  int   should_post_on_exceptions_flag()  { return _should_post_on_exceptions_flag; }
+  void  set_should_post_on_exceptions_flag(int val)  { _should_post_on_exceptions_flag = val; }
+
  private:
   ThreadStatistics *_thread_stat;