src/share/vm/oops/instanceKlass.cpp

*** 243,252 ****
--- 243,253 ----
    set_array_name(NULL);
    set_inner_classes(NULL);
    set_static_oop_field_count(0);
    set_nonstatic_field_size(0);
    set_is_marked_dependent(false);
+   set_has_unloaded_dependent(false);
    set_init_state(InstanceKlass::allocated);
    set_init_thread(NULL);
    set_reference_type(rt);
    set_oop_map_cache(NULL);
    set_jni_ids(NULL);
*** 1799,1808 ****
--- 1800,1812 ----
      id = jmeths[idnum+1];                       // Look up the id (may be NULL)
    }
    return id;
  }
  
+ int nmethodBucket::decrement() {
+   return Atomic::add(-1, (volatile int *)&_count);
+ }
  
  //
  // Walk the list of dependent nmethods searching for nmethods which
  // are dependent on the changes that were passed in and mark them for
  // deoptimization.  Returns the number of nmethods found.
*** 1813,1823 ****
    nmethodBucket* b = _dependencies;
    while (b != NULL) {
      nmethod* nm = b->get_nmethod();
      // since dependencies aren't removed until an nmethod becomes a zombie,
      // the dependency list may contain nmethods which aren't alive.
!     if (nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
        if (TraceDependencies) {
          ResourceMark rm;
          tty->print_cr("Marked for deoptimization");
          tty->print_cr("  context = %s", this->external_name());
          changes.print();
--- 1817,1827 ----
    nmethodBucket* b = _dependencies;
    while (b != NULL) {
      nmethod* nm = b->get_nmethod();
      // since dependencies aren't removed until an nmethod becomes a zombie,
      // the dependency list may contain nmethods which aren't alive.
!     if (b->count() > 0 && nm->is_alive() && !nm->is_marked_for_deoptimization() && nm->check_dependency_on(changes)) {
        if (TraceDependencies) {
          ResourceMark rm;
          tty->print_cr("Marked for deoptimization");
          tty->print_cr("  context = %s", this->external_name());
          changes.print();
*** 1830,1839 ****
--- 1834,1880 ----
      b = b->next();
    }
    return found;
  }
  
+ void InstanceKlass::clean_dependent_nmethods() {
+   assert_locked_or_safepoint(CodeCache_lock);
+ 
+   if (has_unloaded_dependent()) {
+     nmethodBucket* b = _dependencies;
+     nmethodBucket* last = NULL;
+     while (b != NULL) {
+       assert(b->count() >= 0, err_msg("bucket count: %d", b->count()));
+ 
+       nmethodBucket* next = b->next();
+ 
+       if (b->count() == 0) {
+         if (last == NULL) {
+           _dependencies = next;
+         } else {
+           last->set_next(next);
+         }
+         delete b;
+         // last stays the same.
+       } else {
+         last = b;
+       }
+ 
+       b = next;
+     }
+     set_has_unloaded_dependent(false);
+   }
+ #ifdef ASSERT
+   else {
+     // Verification
+     for (nmethodBucket* b = _dependencies; b != NULL; b = b->next()) {
+       assert(b->count() >= 0, err_msg("bucket count: %d", b->count()));
+       assert(b->count() != 0, "empty buckets need to be cleaned");
+     }
+   }
+ #endif
+ }
  
  //
  // Add an nmethodBucket to the list of dependencies for this nmethod.
  // It's possible that an nmethod has multiple dependencies on this klass
  // so a count is kept for each bucket to guarantee that creation and
*** 1864,1880 ****
    assert_locked_or_safepoint(CodeCache_lock);
    nmethodBucket* b = _dependencies;
    nmethodBucket* last = NULL;
    while (b != NULL) {
      if (nm == b->get_nmethod()) {
!       if (b->decrement() == 0) {
!         if (last == NULL) {
!           _dependencies = b->next();
!         } else {
!           last->set_next(b->next());
!         }
!         delete b;
        }
        return;
      }
      last = b;
      b = b->next();
--- 1905,1918 ----
    assert_locked_or_safepoint(CodeCache_lock);
    nmethodBucket* b = _dependencies;
    nmethodBucket* last = NULL;
    while (b != NULL) {
      if (nm == b->get_nmethod()) {
!       int val = b->decrement();
!       guarantee(val >= 0, err_msg("Underflow: %d", val));
!       if (val == 0) {
!         set_has_unloaded_dependent(true);
        }
        return;
      }
      last = b;
      b = b->next();
*** 1909,1918 ****
--- 1947,1961 ----
  
  bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
    nmethodBucket* b = _dependencies;
    while (b != NULL) {
      if (nm == b->get_nmethod()) {
+ #ifdef ASSERT
+       int count = b->count();
+       assert(count >= 0, "Just check if we ever get here 1");
+       assert(count > 0,  "Just check if we ever get here 2");
+ #endif
        return true;
      }
      b = b->next();
    }
    return false;
*** 2207,2217 ****
  }
  
  #endif // INCLUDE_ALL_GCS
  
  void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
!   assert(is_loader_alive(is_alive), "this klass should be live");
    if (is_interface()) {
      if (ClassUnloading) {
        Klass* impl = implementor();
        if (impl != NULL) {
          if (!impl->is_loader_alive(is_alive)) {
--- 2250,2260 ----
  }
  
  #endif // INCLUDE_ALL_GCS
  
  void InstanceKlass::clean_implementors_list(BoolObjectClosure* is_alive) {
!   assert(class_loader_data()->is_alive(is_alive), "this klass should be live");
    if (is_interface()) {
      if (ClassUnloading) {
        Klass* impl = implementor();
        if (impl != NULL) {
          if (!impl->is_loader_alive(is_alive)) {