Mercurial > hg > truffle
diff src/share/vm/oops/instanceKlass.hpp @ 977:74a5db69c1fe
6419370: 4/4 new jmethodID code has tiny holes in synchronization
Summary: Fix races in jmethodID cache and JNI itable index cache.
Reviewed-by: ikrylov, acorn
| author | dcubed |
|---|---|
| date | Mon, 21 Sep 2009 09:30:24 -0600 |
| parents | 83c29a26f67c |
| children | 987e948ebbc8 |
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--- a/src/share/vm/oops/instanceKlass.hpp Wed Sep 16 15:42:46 2009 -0400 +++ b/src/share/vm/oops/instanceKlass.hpp Mon Sep 21 09:30:24 2009 -0600 @@ -465,6 +465,10 @@ // RedefineClasses() support for previous versions: void add_previous_version(instanceKlassHandle ikh, BitMap *emcp_methods, int emcp_method_count); + // If the _previous_versions array is non-NULL, then this klass + // has been redefined at least once even if we aren't currently + // tracking a previous version. + bool has_been_redefined() const { return _previous_versions != NULL; } bool has_previous_version() const; void init_previous_versions() { _previous_versions = NULL; @@ -506,9 +510,14 @@ void set_bootstrap_method(oop mh) { oop_store(&_bootstrap_method, mh); } // jmethodID support - static jmethodID get_jmethod_id(instanceKlassHandle ik_h, size_t idnum, - jmethodID new_id, jmethodID* new_jmeths); - static jmethodID jmethod_id_for_impl(instanceKlassHandle ik_h, methodHandle method_h); + static jmethodID get_jmethod_id(instanceKlassHandle ik_h, + methodHandle method_h); + static jmethodID get_jmethod_id_fetch_or_update(instanceKlassHandle ik_h, + size_t idnum, jmethodID new_id, jmethodID* new_jmeths, + jmethodID* to_dealloc_id_p, + jmethodID** to_dealloc_jmeths_p); + static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum, + size_t *length_p, jmethodID* id_p); jmethodID jmethod_id_or_null(methodOop method); // cached itable index support @@ -754,6 +763,11 @@ void set_init_thread(Thread *thread) { _init_thread = thread; } u2 idnum_allocated_count() const { return _idnum_allocated_count; } + // The RedefineClasses() API can cause new method idnums to be needed + // which will cause the caches to grow. Safety requires different + // cache management logic if the caches can grow instead of just + // going from NULL to non-NULL. + bool idnum_can_increment() const { return has_been_redefined(); } jmethodID* methods_jmethod_ids_acquire() const { return (jmethodID*)OrderAccess::load_ptr_acquire(&_methods_jmethod_ids); } void release_set_methods_jmethod_ids(jmethodID* jmeths)