code review for JVM/TI DynamicCodeGenerated event fix (7039447)

[Daniel D. Daugherty]

On 4/28/2011 7:37 AM, Daniel D. Daugherty wrote:
> I'm going to take another look at what I can do to clean this
> up a bit...

This version should address your concerns and Dmitry's also.
Especially since Dmitry suggested the specific code in the
post_dynamic_code_generated_internal() call. I just added
the comment and reformatted it a bit...

Dan


--- a/src/share/vm/prims/jvmtiImpl.cpp  Sat Apr 23 00:33:38 2011 -0400
+++ b/src/share/vm/prims/jvmtiImpl.cpp  Thu Apr 28 07:44:01 2011 -0600
@@ -38,6 +38,7 @@
 #include "runtime/handles.inline.hpp"
 #include "runtime/interfaceSupport.hpp"
 #include "runtime/javaCalls.hpp"
+#include "runtime/os.hpp"
 #include "runtime/serviceThread.hpp"
 #include "runtime/signature.hpp"
 #include "runtime/vframe.hpp"
@@ -939,10 +940,15 @@
   nmethodLocker::lock_nmethod(nm, true /* zombie_ok */);
   return event;
 }
+
 JvmtiDeferredEvent JvmtiDeferredEvent::dynamic_code_generated_event(
       const char* name, const void* code_begin, const void* code_end) {
   JvmtiDeferredEvent event = 
JvmtiDeferredEvent(TYPE_DYNAMIC_CODE_GENERATED);
-  event._event_data.dynamic_code_generated.name = name;
+  // Need to make a copy of the name since we don't know how long
+  // the event poster will keep it around after we enqueue the
+  // deferred event and return. strdup() failure is handled in
+  // the post() routine below.
+  event._event_data.dynamic_code_generated.name = os::strdup(name);
   event._event_data.dynamic_code_generated.code_begin = code_begin;
   event._event_data.dynamic_code_generated.code_end = code_end;
   return event;
@@ -968,12 +974,17 @@
       nmethodLocker::unlock_nmethod(nm);
       break;
     }
-    case TYPE_DYNAMIC_CODE_GENERATED:
+    case TYPE_DYNAMIC_CODE_GENERATED: {
       JvmtiExport::post_dynamic_code_generated_internal(
-        _event_data.dynamic_code_generated.name,
+        // if strdup failed give the event a default name
+        (_event_data.dynamic_code_generated.name == NULL)
+          ? "unknown_code" : _event_data.dynamic_code_generated.name,
         _event_data.dynamic_code_generated.code_begin,
         _event_data.dynamic_code_generated.code_end);
+      // release our copy
+      os::free(_event_data.dynamic_code_generated.name);
       break;
+    }
     default:
       ShouldNotReachHere();
   }