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6419370: 4/4 new jmethodID code has tiny holes in synchronization

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Fix races in jmethodID cache and JNI itable index cache.

Reviewed-by: ikrylov, acorn
This commit is contained in:
Daniel D. Daugherty 2009-09-21 09:30:24 -06:00
parent 9ed976194b
commit 2a4f284029
4 changed files with 204 additions and 53 deletions
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20
hotspot/src/share/vm/oops/instanceKlass.hpp
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@ -465,6 +465,10 @@ class instanceKlass: public Klass {
// 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 @@ class instanceKlass: public Klass {
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 @@ private:
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)