8079205: CallSite dependency tracking is broken after sun.misc.Cleaner became automatically cleared

Reviewed-by: roland, psandoz, plevart, kbarrett, jrose

hotspot/src/share/vm/ci/ciCallSite.cpp

@@ -49,25 +49,6 @@ ciMethodHandle* ciCallSite::get_target() const {
   return CURRENT_ENV->get_object(method_handle_oop)->as_method_handle();
 }
 
-// ------------------------------------------------------------------
-// ciCallSite::get_context
-//
-// Return the target MethodHandle of this CallSite.
-ciKlass* ciCallSite::get_context() {
-  assert(!is_constant_call_site(), "");
-
-  VM_ENTRY_MARK;
-  oop call_site_oop = get_oop();
-  InstanceKlass* ctxk = MethodHandles::get_call_site_context(call_site_oop);
-  if (ctxk == NULL) {
-    // The call site doesn't have a context associated. Set it to the default context.
-    oop def_context_oop = java_lang_invoke_CallSite::default_context();
-    java_lang_invoke_CallSite::set_context_cas(call_site_oop, def_context_oop, /*expected=*/NULL);
-    ctxk = MethodHandles::get_call_site_context(call_site_oop);
-  }
-  return (CURRENT_ENV->get_metadata(ctxk))->as_klass();
-}
-
 // ------------------------------------------------------------------
 // ciCallSite::print
 //

hotspot/src/share/vm/ci/ciCallSite.hpp

@@ -43,7 +43,6 @@ public:
 
   // Return the target MethodHandle of this CallSite.
   ciMethodHandle* get_target() const;
-  ciKlass* get_context();
 
   void print();
 };

hotspot/src/share/vm/ci/ciInstanceKlass.cpp

@@ -453,8 +453,12 @@ int ciInstanceKlass::compute_nonstatic_fields() {
 
   if (fields == NULL) {
     // This can happen if this class (java.lang.Class) has invisible fields.
-    _nonstatic_fields = super_fields;
+    if (super_fields != NULL) {
-    return super_fields->length();
+      _nonstatic_fields = super_fields;
+      return super_fields->length();
+    } else {
+      return 0;
+    }
   }
 
   int flen = fields->length();

hotspot/src/share/vm/classfile/javaClasses.cpp

@@ -2967,47 +2967,42 @@ int java_lang_invoke_MethodType::rtype_slot_count(oop mt) {
 
 int java_lang_invoke_CallSite::_target_offset;
 int java_lang_invoke_CallSite::_context_offset;
-int java_lang_invoke_CallSite::_default_context_offset;
 
 void java_lang_invoke_CallSite::compute_offsets() {
   Klass* k = SystemDictionary::CallSite_klass();
   if (k != NULL) {
     compute_offset(_target_offset, k, vmSymbols::target_name(), vmSymbols::java_lang_invoke_MethodHandle_signature());
-    compute_offset(_context_offset, k, vmSymbols::context_name(), vmSymbols::sun_misc_Cleaner_signature());
+    compute_offset(_context_offset, k, vmSymbols::context_name(),
-    compute_offset(_default_context_offset, k,
+                   vmSymbols::java_lang_invoke_MethodHandleNatives_CallSiteContext_signature());
-                   vmSymbols::DEFAULT_CONTEXT_name(), vmSymbols::sun_misc_Cleaner_signature(),
-                   /*is_static=*/true, /*allow_super=*/false);
   }
 }
 
-oop java_lang_invoke_CallSite::context_volatile(oop call_site) {
+oop java_lang_invoke_CallSite::context(oop call_site) {
   assert(java_lang_invoke_CallSite::is_instance(call_site), "");
 
-  oop dep_oop = call_site->obj_field_volatile(_context_offset);
+  oop dep_oop = call_site->obj_field(_context_offset);
   return dep_oop;
 }
 
-void java_lang_invoke_CallSite::set_context_volatile(oop call_site, oop context) {
+// Support for java_lang_invoke_MethodHandleNatives_CallSiteContext
-  assert(java_lang_invoke_CallSite::is_instance(call_site), "");
-  call_site->obj_field_put_volatile(_context_offset, context);
-}
 
-bool java_lang_invoke_CallSite::set_context_cas(oop call_site, oop context, oop expected) {
+int java_lang_invoke_MethodHandleNatives_CallSiteContext::_vmdependencies_offset;
-  assert(java_lang_invoke_CallSite::is_instance(call_site), "");
+
-  HeapWord* context_addr = call_site->obj_field_addr<HeapWord>(_context_offset);
+void java_lang_invoke_MethodHandleNatives_CallSiteContext::compute_offsets() {
-  oop res = oopDesc::atomic_compare_exchange_oop(context, context_addr, expected, true);
+  Klass* k = SystemDictionary::Context_klass();
-  bool success = (res == expected);
+  if (k != NULL) {
-  if (success) {
+    CALLSITECONTEXT_INJECTED_FIELDS(INJECTED_FIELD_COMPUTE_OFFSET);
-    update_barrier_set((void*)context_addr, context);
   }
-  return success;
 }
 
-oop java_lang_invoke_CallSite::default_context() {
+nmethodBucket* java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(oop call_site) {
-  InstanceKlass* ik = InstanceKlass::cast(SystemDictionary::CallSite_klass());
+  assert(java_lang_invoke_MethodHandleNatives_CallSiteContext::is_instance(call_site), "");
-  oop def_context_oop = ik->java_mirror()->obj_field(_default_context_offset);
+  return (nmethodBucket*) (address) call_site->long_field(_vmdependencies_offset);
-  assert(!oopDesc::is_null(def_context_oop), "");
+}
-  return def_context_oop;
+
+void java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(oop call_site, nmethodBucket* context) {
+  assert(java_lang_invoke_MethodHandleNatives_CallSiteContext::is_instance(call_site), "");
+  call_site->long_field_put(_vmdependencies_offset, (jlong) (address) context);
 }
 
 // Support for java_security_AccessControlContext
@@ -3403,6 +3398,7 @@ void JavaClasses::compute_offsets() {
   java_lang_invoke_LambdaForm::compute_offsets();
   java_lang_invoke_MethodType::compute_offsets();
   java_lang_invoke_CallSite::compute_offsets();
+  java_lang_invoke_MethodHandleNatives_CallSiteContext::compute_offsets();
   java_security_AccessControlContext::compute_offsets();
   // Initialize reflection classes. The layouts of these classes
   // changed with the new reflection implementation in JDK 1.4, and

hotspot/src/share/vm/classfile/javaClasses.hpp

@@ -1170,8 +1170,6 @@ class java_lang_invoke_CallSite: AllStatic {
 private:
   static int _target_offset;
   static int _context_offset;
-  static int _default_context_offset;
-
 
   static void compute_offsets();
 
@@ -1181,11 +1179,7 @@ public:
   static void         set_target(          oop site, oop target);
   static void         set_target_volatile( oop site, oop target);
 
-  static oop              context_volatile(oop site);
+  static oop              context(oop site);
-  static void         set_context_volatile(oop site, oop context);
-  static bool         set_context_cas     (oop site, oop context, oop expected);
-
-  static oop default_context();
 
   // Testers
   static bool is_subclass(Klass* klass) {
@@ -1197,6 +1191,31 @@ public:
   static int target_offset_in_bytes()           { return _target_offset; }
 };
 
+// Interface to java.lang.invoke.MethodHandleNatives$CallSiteContext objects
+
+#define CALLSITECONTEXT_INJECTED_FIELDS(macro) \
+  macro(java_lang_invoke_MethodHandleNatives_CallSiteContext, vmdependencies, intptr_signature, false)
+
+class java_lang_invoke_MethodHandleNatives_CallSiteContext : AllStatic {
+  friend class JavaClasses;
+
+private:
+  static int _vmdependencies_offset;
+
+  static void compute_offsets();
+
+public:
+  // Accessors
+  static nmethodBucket* vmdependencies(oop context);
+  static void       set_vmdependencies(oop context, nmethodBucket* bucket);
+
+  // Testers
+  static bool is_subclass(Klass* klass) {
+    return klass->is_subclass_of(SystemDictionary::Context_klass());
+  }
+  static bool is_instance(oop obj);
+};
+
 // Interface to java.security.AccessControlContext objects
 
 class java_security_AccessControlContext: AllStatic {
@@ -1406,7 +1425,8 @@ class InjectedField {
 #define ALL_INJECTED_FIELDS(macro)          \
   CLASS_INJECTED_FIELDS(macro)              \
   CLASSLOADER_INJECTED_FIELDS(macro)        \
-  MEMBERNAME_INJECTED_FIELDS(macro)
+  MEMBERNAME_INJECTED_FIELDS(macro)         \
+  CALLSITECONTEXT_INJECTED_FIELDS(macro)
 
 // Interface to hard-coded offset checking
 

hotspot/src/share/vm/classfile/javaClasses.inline.hpp

@@ -49,6 +49,10 @@ inline bool java_lang_invoke_CallSite::is_instance(oop obj) {
   return obj != NULL && is_subclass(obj->klass());
 }
 
+inline bool java_lang_invoke_MethodHandleNatives_CallSiteContext::is_instance(oop obj) {
+  return obj != NULL && is_subclass(obj->klass());
+}
+
 inline bool java_lang_invoke_MemberName::is_instance(oop obj) {
   return obj != NULL && is_subclass(obj->klass());
 }

hotspot/src/share/vm/classfile/systemDictionary.hpp

@@ -159,6 +159,7 @@ class Ticks;
   do_klass(MethodType_klass,                            java_lang_invoke_MethodType,               Pre                 ) \
   do_klass(BootstrapMethodError_klass,                  java_lang_BootstrapMethodError,            Pre                 ) \
   do_klass(CallSite_klass,                              java_lang_invoke_CallSite,                 Pre                 ) \
+  do_klass(Context_klass,                               java_lang_invoke_MethodHandleNatives_CallSiteContext, Pre      ) \
   do_klass(ConstantCallSite_klass,                      java_lang_invoke_ConstantCallSite,         Pre                 ) \
   do_klass(MutableCallSite_klass,                       java_lang_invoke_MutableCallSite,          Pre                 ) \
   do_klass(VolatileCallSite_klass,                      java_lang_invoke_VolatileCallSite,         Pre                 ) \

hotspot/src/share/vm/classfile/vmSymbols.hpp

@@ -274,12 +274,14 @@
   /* internal classes known only to the JVM: */                                                   \
   template(java_lang_invoke_MemberName,               "java/lang/invoke/MemberName")              \
   template(java_lang_invoke_MethodHandleNatives,      "java/lang/invoke/MethodHandleNatives")     \
+  template(java_lang_invoke_MethodHandleNatives_CallSiteContext, "java/lang/invoke/MethodHandleNatives$CallSiteContext") \
   template(java_lang_invoke_LambdaForm,               "java/lang/invoke/LambdaForm")              \
   template(java_lang_invoke_ForceInline_signature,    "Ljava/lang/invoke/ForceInline;")           \
   template(java_lang_invoke_DontInline_signature,     "Ljava/lang/invoke/DontInline;")            \
   template(java_lang_invoke_Stable_signature,         "Ljava/lang/invoke/Stable;")                \
   template(java_lang_invoke_LambdaForm_Compiled_signature, "Ljava/lang/invoke/LambdaForm$Compiled;") \
   template(java_lang_invoke_LambdaForm_Hidden_signature, "Ljava/lang/invoke/LambdaForm$Hidden;")  \
+  template(java_lang_invoke_MethodHandleNatives_CallSiteContext_signature, "Ljava/lang/invoke/MethodHandleNatives$CallSiteContext;") \
   /* internal up-calls made only by the JVM, via class sun.invoke.MethodHandleNatives: */         \
   template(findMethodHandleType_name,                 "findMethodHandleType")                     \
   template(findMethodHandleType_signature,       "(Ljava/lang/Class;[Ljava/lang/Class;)Ljava/lang/invoke/MethodType;") \
@@ -401,7 +403,7 @@
   template(protection_domain_name,                    "protection_domain")                        \
   template(signers_name,                              "signers_name")                             \
   template(loader_data_name,                          "loader_data")                              \
-  template(dependencies_name,                         "dependencies")                             \
+  template(vmdependencies_name,                       "vmdependencies")                           \
   template(input_stream_void_signature,               "(Ljava/io/InputStream;)V")                 \
   template(getFileURL_name,                           "getFileURL")                               \
   template(getFileURL_signature,                      "(Ljava/io/File;)Ljava/net/URL;")           \

hotspot/src/share/vm/code/codeCache.cpp

@@ -1047,40 +1047,6 @@ void CodeCache::flush_dependents_on(instanceKlassHandle dependee) {
   }
 }
 
-// Flushes compiled methods dependent on a particular CallSite
-// instance when its target is different than the given MethodHandle.
-void CodeCache::flush_dependents_on(Handle call_site, Handle method_handle) {
-  assert_lock_strong(Compile_lock);
-
-  if (number_of_nmethods_with_dependencies() == 0) return;
-
-  // CodeCache can only be updated by a thread_in_VM and they will all be
-  // stopped during the safepoint so CodeCache will be safe to update without
-  // holding the CodeCache_lock.
-
-  CallSiteDepChange changes(call_site(), method_handle());
-
-  // Compute the dependent nmethods that have a reference to a
-  // CallSite object.  We use InstanceKlass::mark_dependent_nmethod
-  // directly instead of CodeCache::mark_for_deoptimization because we
-  // want dependents on the call site class only not all classes in
-  // the ContextStream.
-  int marked = 0;
-  {
-    MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
-    InstanceKlass* ctxk = MethodHandles::get_call_site_context(call_site());
-    if (ctxk == NULL) {
-      return; // No dependencies to invalidate yet.
-    }
-    marked = ctxk->mark_dependent_nmethods(changes);
-  }
-  if (marked > 0) {
-    // At least one nmethod has been marked for deoptimization
-    VM_Deoptimize op;
-    VMThread::execute(&op);
-  }
-}
-
 #ifdef HOTSWAP
 // Flushes compiled methods dependent on dependee in the evolutionary sense
 void CodeCache::flush_evol_dependents_on(instanceKlassHandle ev_k_h) {

hotspot/src/share/vm/code/codeCache.hpp

@@ -224,7 +224,6 @@ class CodeCache : AllStatic {
 
   // Flushing and deoptimization
   static void flush_dependents_on(instanceKlassHandle dependee);
-  static void flush_dependents_on(Handle call_site, Handle method_handle);
 #ifdef HOTSWAP
   // Flushing and deoptimization in case of evolution
   static void flush_evol_dependents_on(instanceKlassHandle dependee);

hotspot/src/share/vm/code/dependencies.cpp

@@ -117,9 +117,7 @@ void Dependencies::assert_has_no_finalizable_subclasses(ciKlass* ctxk) {
 }
 
 void Dependencies::assert_call_site_target_value(ciCallSite* call_site, ciMethodHandle* method_handle) {
-  ciKlass* ctxk = call_site->get_context();
+  assert_common_2(call_site_target_value, call_site, method_handle);
-  check_ctxk(ctxk);
-  assert_common_3(call_site_target_value, ctxk, call_site, method_handle);
 }
 
 // Helper function.  If we are adding a new dep. under ctxk2,
@@ -175,7 +173,6 @@ void Dependencies::assert_common_2(DepType dept,
       }
     }
   } else {
-    assert(dep_implicit_context_arg(dept) == 0, "sanity");
     if (note_dep_seen(dept, x0) && note_dep_seen(dept, x1)) {
       // look in this bucket for redundant assertions
       const int stride = 2;
@@ -389,7 +386,7 @@ int Dependencies::_dep_args[TYPE_LIMIT] = {
   3, // unique_concrete_subtypes_2 ctxk, k1, k2
   3, // unique_concrete_methods_2 ctxk, m1, m2
   1, // no_finalizable_subclasses ctxk
-  3  // call_site_target_value ctxk, call_site, method_handle
+  2  // call_site_target_value call_site, method_handle
 };
 
 const char* Dependencies::dep_name(Dependencies::DepType dept) {
@@ -1515,16 +1512,11 @@ Klass* Dependencies::check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepCh
   return find_finalizable_subclass(search_at);
 }
 
-Klass* Dependencies::check_call_site_target_value(Klass* recorded_ctxk, oop call_site, oop method_handle, CallSiteDepChange* changes) {
+Klass* Dependencies::check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes) {
-  assert(call_site->is_a(SystemDictionary::CallSite_klass()),     "sanity");
+  assert(!oopDesc::is_null(call_site), "sanity");
   assert(!oopDesc::is_null(method_handle), "sanity");
+  assert(call_site->is_a(SystemDictionary::CallSite_klass()),     "sanity");
 
-  Klass* call_site_ctxk = MethodHandles::get_call_site_context(call_site);
-  assert(!Klass::is_null(call_site_ctxk), "call site context should be initialized already");
-  if (recorded_ctxk != call_site_ctxk) {
-    // Stale context
-    return recorded_ctxk;
-  }
   if (changes == NULL) {
     // Validate all CallSites
     if (java_lang_invoke_CallSite::target(call_site) != method_handle)
@@ -1599,7 +1591,7 @@ Klass* Dependencies::DepStream::check_call_site_dependency(CallSiteDepChange* ch
   Klass* witness = NULL;
   switch (type()) {
   case call_site_target_value:
-    witness = check_call_site_target_value(context_type(), argument_oop(1), argument_oop(2), changes);
+    witness = check_call_site_target_value(argument_oop(0), argument_oop(1), changes);
     break;
   default:
     witness = NULL;

hotspot/src/share/vm/code/dependencies.hpp

@@ -173,7 +173,7 @@ class Dependencies: public ResourceObj {
     non_klass_types     = (1 << call_site_target_value),
     klass_types         = all_types & ~non_klass_types,
 
-    non_ctxk_types      = (1 << evol_method),
+    non_ctxk_types      = (1 << evol_method) | (1 << call_site_target_value),
     implicit_ctxk_types = 0,
     explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
 
@@ -330,7 +330,7 @@ class Dependencies: public ResourceObj {
   static Klass* check_exclusive_concrete_methods(Klass* ctxk, Method* m1, Method* m2,
                                                    KlassDepChange* changes = NULL);
   static Klass* check_has_no_finalizable_subclasses(Klass* ctxk, KlassDepChange* changes = NULL);
-  static Klass* check_call_site_target_value(Klass* recorded_ctxk, oop call_site, oop method_handle, CallSiteDepChange* changes = NULL);
+  static Klass* check_call_site_target_value(oop call_site, oop method_handle, CallSiteDepChange* changes = NULL);
   // A returned Klass* is NULL if the dependency assertion is still
   // valid.  A non-NULL Klass* is a 'witness' to the assertion
   // failure, a point in the class hierarchy where the assertion has
@@ -496,7 +496,7 @@ class Dependencies: public ResourceObj {
     bool next();
 
     DepType type()               { return _type; }
-    bool is_oop_argument(int i)  { return type() == call_site_target_value && i > 0; }
+    bool is_oop_argument(int i)  { return type() == call_site_target_value; }
     uintptr_t get_identifier(int i);
 
     int argument_count()         { return dep_args(type()); }

hotspot/src/share/vm/code/nmethod.cpp

@@ -565,13 +565,18 @@ nmethod* nmethod::new_nmethod(methodHandle method,
       // the number of methods compiled.  For applications with a lot
       // classes the slow way is too slow.
       for (Dependencies::DepStream deps(nm); deps.next(); ) {
-        Klass* klass = deps.context_type();
+        if (deps.type() == Dependencies::call_site_target_value) {
-        if (klass == NULL) {
+          // CallSite dependencies are managed on per-CallSite instance basis.
-          continue;  // ignore things like evol_method
+          oop call_site = deps.argument_oop(0);
+          MethodHandles::add_dependent_nmethod(call_site, nm);
+        } else {
+          Klass* klass = deps.context_type();
+          if (klass == NULL) {
+            continue;  // ignore things like evol_method
+          }
+          // record this nmethod as dependent on this klass
+          InstanceKlass::cast(klass)->add_dependent_nmethod(nm);
         }
-
-        // record this nmethod as dependent on this klass
-        InstanceKlass::cast(klass)->add_dependent_nmethod(nm);
       }
       NOT_PRODUCT(nmethod_stats.note_nmethod(nm));
       if (PrintAssembly || CompilerOracle::has_option_string(method, "PrintAssembly")) {
@@ -1464,13 +1469,20 @@ void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {
   if (!has_flushed_dependencies()) {
     set_has_flushed_dependencies();
     for (Dependencies::DepStream deps(this); deps.next(); ) {
-      Klass* klass = deps.context_type();
+      if (deps.type() == Dependencies::call_site_target_value) {
-      if (klass == NULL)  continue;  // ignore things like evol_method
+        // CallSite dependencies are managed on per-CallSite instance basis.
-
+        oop call_site = deps.argument_oop(0);
-      // During GC the is_alive closure is non-NULL, and is used to
+        MethodHandles::remove_dependent_nmethod(call_site, this);
-      // determine liveness of dependees that need to be updated.
+      } else {
-      if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
+        Klass* klass = deps.context_type();
-        InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
+        if (klass == NULL) {
+          continue;  // ignore things like evol_method
+        }
+        // During GC the is_alive closure is non-NULL, and is used to
+        // determine liveness of dependees that need to be updated.
+        if (is_alive == NULL || klass->is_loader_alive(is_alive)) {
+          InstanceKlass::cast(klass)->remove_dependent_nmethod(this);
+        }
       }
     }
   }

hotspot/src/share/vm/oops/instanceKlass.cpp

@@ -1830,11 +1830,10 @@ int nmethodBucket::decrement() {
 // are dependent on the changes that were passed in and mark them for
 // deoptimization.  Returns the number of nmethods found.
 //
-int InstanceKlass::mark_dependent_nmethods(DepChange& changes) {
+int nmethodBucket::mark_dependent_nmethods(nmethodBucket* deps, DepChange& changes) {
   assert_locked_or_safepoint(CodeCache_lock);
   int found = 0;
-  nmethodBucket* b = _dependencies;
+  for (nmethodBucket* b = deps; b != NULL; b = b->next()) {
-  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.
@@ -1842,7 +1841,6 @@ int InstanceKlass::mark_dependent_nmethods(DepChange& changes) {
       if (TraceDependencies) {
         ResourceMark rm;
         tty->print_cr("Marked for deoptimization");
-        tty->print_cr("  context = %s", this->external_name());
         changes.print();
         nm->print();
         nm->print_dependencies();
@@ -1850,36 +1848,119 @@ int InstanceKlass::mark_dependent_nmethods(DepChange& changes) {
       nm->mark_for_deoptimization();
       found++;
     }
-    b = b->next();
   }
   return found;
 }
 
+//
+// 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
+// deletion of dependencies is consistent. Returns new head of the list.
+//
+nmethodBucket* nmethodBucket::add_dependent_nmethod(nmethodBucket* deps, nmethod* nm) {
+  assert_locked_or_safepoint(CodeCache_lock);
+  for (nmethodBucket* b = deps; b != NULL; b = b->next()) {
+    if (nm == b->get_nmethod()) {
+      b->increment();
+      return deps;
+    }
+  }
+  return new nmethodBucket(nm, deps);
+}
+
+//
+// Decrement count of the nmethod in the dependency list and remove
+// the bucket completely when the count goes to 0.  This method must
+// find a corresponding bucket otherwise there's a bug in the
+// recording of dependencies. Returns true if the bucket is ready for reclamation.
+//
+bool nmethodBucket::remove_dependent_nmethod(nmethodBucket* deps, nmethod* nm) {
+  assert_locked_or_safepoint(CodeCache_lock);
+
+  for (nmethodBucket* b = deps; b != NULL; b = b->next()) {
+    if (nm == b->get_nmethod()) {
+      int val = b->decrement();
+      guarantee(val >= 0, err_msg("Underflow: %d", val));
+      return (val == 0);
+    }
+  }
+#ifdef ASSERT
+  tty->print_raw_cr("### can't find dependent nmethod");
+  nm->print();
+#endif // ASSERT
+  ShouldNotReachHere();
+  return false;
+}
+
+//
+// Reclaim all unused buckets. Returns new head of the list.
+//
+nmethodBucket* nmethodBucket::clean_dependent_nmethods(nmethodBucket* deps) {
+  nmethodBucket* first = deps;
+  nmethodBucket* last = NULL;
+  nmethodBucket* b = first;
+
+  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) {
+        first = next;
+      } else {
+        last->set_next(next);
+      }
+      delete b;
+      // last stays the same.
+    } else {
+      last = b;
+    }
+    b = next;
+  }
+  return first;
+}
+
+#ifndef PRODUCT
+void nmethodBucket::print_dependent_nmethods(nmethodBucket* deps, bool verbose) {
+  int idx = 0;
+  for (nmethodBucket* b = deps; b != NULL; b = b->next()) {
+    nmethod* nm = b->get_nmethod();
+    tty->print("[%d] count=%d { ", idx++, b->count());
+    if (!verbose) {
+      nm->print_on(tty, "nmethod");
+      tty->print_cr(" } ");
+    } else {
+      nm->print();
+      nm->print_dependencies();
+      tty->print_cr("--- } ");
+    }
+  }
+}
+
+bool nmethodBucket::is_dependent_nmethod(nmethodBucket* deps, nmethod* nm) {
+  for (nmethodBucket* b = deps; b != NULL; b = b->next()) {
+    if (nm == b->get_nmethod()) {
+#ifdef ASSERT
+      int count = b->count();
+      assert(count >= 0, err_msg("count shouldn't be negative: %d", count));
+#endif
+      return true;
+    }
+  }
+  return false;
+}
+#endif //PRODUCT
+
+int InstanceKlass::mark_dependent_nmethods(DepChange& changes) {
+  assert_locked_or_safepoint(CodeCache_lock);
+  return nmethodBucket::mark_dependent_nmethods(_dependencies, changes);
+}
+
 void InstanceKlass::clean_dependent_nmethods() {
   assert_locked_or_safepoint(CodeCache_lock);
 
   if (has_unloaded_dependent()) {
-    nmethodBucket* b = _dependencies;
+    _dependencies = nmethodBucket::clean_dependent_nmethods(_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
@@ -1893,90 +1974,26 @@ void InstanceKlass::clean_dependent_nmethods() {
 #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
-// deletion of dependencies is consistent.
-//
 void InstanceKlass::add_dependent_nmethod(nmethod* nm) {
   assert_locked_or_safepoint(CodeCache_lock);
-  nmethodBucket* b = _dependencies;
+  _dependencies = nmethodBucket::add_dependent_nmethod(_dependencies, nm);
-  nmethodBucket* last = NULL;
-  while (b != NULL) {
-    if (nm == b->get_nmethod()) {
-      b->increment();
-      return;
-    }
-    b = b->next();
-  }
-  _dependencies = new nmethodBucket(nm, _dependencies);
 }
 
-
-//
-// Decrement count of the nmethod in the dependency list and remove
-// the bucket competely when the count goes to 0.  This method must
-// find a corresponding bucket otherwise there's a bug in the
-// recording of dependecies.
-//
 void InstanceKlass::remove_dependent_nmethod(nmethod* nm) {
   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();
-  }
-#ifdef ASSERT
-  tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
-  nm->print();
-#endif // ASSERT
-  ShouldNotReachHere();
-}
 
+  if (nmethodBucket::remove_dependent_nmethod(_dependencies, nm)) {
+    set_has_unloaded_dependent(true);
+  }
+}
 
 #ifndef PRODUCT
 void InstanceKlass::print_dependent_nmethods(bool verbose) {
-  nmethodBucket* b = _dependencies;
+  nmethodBucket::print_dependent_nmethods(_dependencies, verbose);
-  int idx = 0;
-  while (b != NULL) {
-    nmethod* nm = b->get_nmethod();
-    tty->print("[%d] count=%d { ", idx++, b->count());
-    if (!verbose) {
-      nm->print_on(tty, "nmethod");
-      tty->print_cr(" } ");
-    } else {
-      nm->print();
-      nm->print_dependencies();
-      tty->print_cr("--- } ");
-    }
-    b = b->next();
-  }
 }
 
-
 bool InstanceKlass::is_dependent_nmethod(nmethod* nm) {
-  nmethodBucket* b = _dependencies;
+  return nmethodBucket::is_dependent_nmethod(_dependencies, nm);
-  while (b != NULL) {
-    if (nm == b->get_nmethod()) {
-#ifdef ASSERT
-      int count = b->count();
-      assert(count >= 0, err_msg("count shouldn't be negative: %d", count));
-#endif
-      return true;
-    }
-    b = b->next();
-  }
-  return false;
 }
 #endif //PRODUCT
 

hotspot/src/share/vm/oops/instanceKlass.hpp

@@ -1297,6 +1297,15 @@ class nmethodBucket: public CHeapObj<mtClass> {
   nmethodBucket* next()                   { return _next; }
   void set_next(nmethodBucket* b)         { _next = b; }
   nmethod* get_nmethod()                  { return _nmethod; }
+
+  static int mark_dependent_nmethods(nmethodBucket* deps, DepChange& changes);
+  static nmethodBucket* add_dependent_nmethod(nmethodBucket* deps, nmethod* nm);
+  static bool remove_dependent_nmethod(nmethodBucket* deps, nmethod* nm);
+  static nmethodBucket* clean_dependent_nmethods(nmethodBucket* deps);
+#ifndef PRODUCT
+  static void print_dependent_nmethods(nmethodBucket* deps, bool verbose);
+  static bool is_dependent_nmethod(nmethodBucket* deps, nmethod* nm);
+#endif //PRODUCT
 };
 
 // An iterator that's used to access the inner classes indices in the

hotspot/src/share/vm/prims/methodHandles.cpp

@@ -942,22 +942,56 @@ int MethodHandles::find_MemberNames(KlassHandle k,
   return rfill + overflow;
 }
 
-// Get context class for a CallSite instance: either extract existing context or use default one.
+void MethodHandles::add_dependent_nmethod(oop call_site, nmethod* nm) {
-InstanceKlass* MethodHandles::get_call_site_context(oop call_site) {
+  assert_locked_or_safepoint(CodeCache_lock);
-  // In order to extract a context the following traversal is performed:
+
-  //   CallSite.context => Cleaner.referent => Class._klass => Klass
+  oop context = java_lang_invoke_CallSite::context(call_site);
-  assert(java_lang_invoke_CallSite::is_instance(call_site), "");
+  nmethodBucket* deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
-  oop context_oop = java_lang_invoke_CallSite::context_volatile(call_site);
+
-  if (oopDesc::is_null(context_oop)) {
+  nmethodBucket* new_deps = nmethodBucket::add_dependent_nmethod(deps, nm);
-    return NULL; // The context hasn't been initialized yet.
+  if (deps != new_deps) {
+    java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context, new_deps);
   }
-  oop context_class_oop = java_lang_ref_Reference::referent(context_oop);
+}
-  if (oopDesc::is_null(context_class_oop)) {
+
-    // The context reference was cleared by GC, so current dependency context
+void MethodHandles::remove_dependent_nmethod(oop call_site, nmethod* nm) {
-    // isn't usable anymore. Context should be fetched from CallSite again.
+  assert_locked_or_safepoint(CodeCache_lock);
-    return NULL;
+
+  oop context = java_lang_invoke_CallSite::context(call_site);
+  nmethodBucket* deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
+
+  if (nmethodBucket::remove_dependent_nmethod(deps, nm)) {
+    nmethodBucket* new_deps = nmethodBucket::clean_dependent_nmethods(deps);
+    if (deps != new_deps) {
+      java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context, new_deps);
+    }
+  }
+}
+
+void MethodHandles::flush_dependent_nmethods(Handle call_site, Handle target) {
+  assert_lock_strong(Compile_lock);
+
+  int marked = 0;
+  CallSiteDepChange changes(call_site(), target());
+  {
+    MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
+
+    oop context = java_lang_invoke_CallSite::context(call_site());
+    nmethodBucket* deps = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context);
+
+    marked = nmethodBucket::mark_dependent_nmethods(deps, changes);
+    if (marked > 0) {
+      nmethodBucket* new_deps = nmethodBucket::clean_dependent_nmethods(deps);
+      if (deps != new_deps) {
+        java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context, new_deps);
+      }
+    }
+  }
+  if (marked > 0) {
+    // At least one nmethod has been marked for deoptimization
+    VM_Deoptimize op;
+    VMThread::execute(&op);
   }
-  return InstanceKlass::cast(java_lang_Class::as_Klass(context_class_oop));
 }
 
 //------------------------------------------------------------------------------
@@ -1276,7 +1310,7 @@ JVM_ENTRY(void, MHN_setCallSiteTargetNormal(JNIEnv* env, jobject igcls, jobject
   {
     // Walk all nmethods depending on this call site.
     MutexLocker mu(Compile_lock, thread);
-    CodeCache::flush_dependents_on(call_site, target);
+    MethodHandles::flush_dependent_nmethods(call_site, target);
     java_lang_invoke_CallSite::set_target(call_site(), target());
   }
 }
@@ -1288,30 +1322,34 @@ JVM_ENTRY(void, MHN_setCallSiteTargetVolatile(JNIEnv* env, jobject igcls, jobjec
   {
     // Walk all nmethods depending on this call site.
     MutexLocker mu(Compile_lock, thread);
-    CodeCache::flush_dependents_on(call_site, target);
+    MethodHandles::flush_dependent_nmethods(call_site, target);
     java_lang_invoke_CallSite::set_target_volatile(call_site(), target());
   }
 }
 JVM_END
 
-JVM_ENTRY(void, MHN_invalidateDependentNMethods(JNIEnv* env, jobject igcls, jobject call_site_jh)) {
+JVM_ENTRY(void, MHN_clearCallSiteContext(JNIEnv* env, jobject igcls, jobject context_jh)) {
-  Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
+  Handle context(THREAD, JNIHandles::resolve_non_null(context_jh));
   {
     // Walk all nmethods depending on this call site.
     MutexLocker mu1(Compile_lock, thread);
 
-    CallSiteDepChange changes(call_site(), Handle());
-
-    InstanceKlass* ctxk = MethodHandles::get_call_site_context(call_site());
-    if (ctxk == NULL) {
-      return; // No dependencies to invalidate yet.
-    }
     int marked = 0;
     {
       MutexLockerEx mu2(CodeCache_lock, Mutex::_no_safepoint_check_flag);
-      marked = ctxk->mark_dependent_nmethods(changes);
+      nmethodBucket* b = java_lang_invoke_MethodHandleNatives_CallSiteContext::vmdependencies(context());
+      while(b != NULL) {
+        nmethod* nm = b->get_nmethod();
+        if (b->count() > 0 && nm->is_alive() && !nm->is_marked_for_deoptimization()) {
+          nm->mark_for_deoptimization();
+          marked++;
+        }
+        nmethodBucket* next = b->next();
+        delete b;
+        b = next;
+      }
+      java_lang_invoke_MethodHandleNatives_CallSiteContext::set_vmdependencies(context(), NULL); // reset context
     }
-    java_lang_invoke_CallSite::set_context_volatile(call_site(), NULL); // Reset call site to initial state
     if (marked > 0) {
       // At least one nmethod has been marked for deoptimization
       VM_Deoptimize op;
@@ -1357,6 +1395,7 @@ JVM_END
 #define MT    JLINV"MethodType;"
 #define MH    JLINV"MethodHandle;"
 #define MEM   JLINV"MemberName;"
+#define CTX   JLINV"MethodHandleNatives$CallSiteContext;"
 
 #define CC (char*)  /*cast a literal from (const char*)*/
 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
@@ -1374,7 +1413,7 @@ static JNINativeMethod MHN_methods[] = {
   {CC"objectFieldOffset",         CC"("MEM")J",                          FN_PTR(MHN_objectFieldOffset)},
   {CC"setCallSiteTargetNormal",   CC"("CS""MH")V",                       FN_PTR(MHN_setCallSiteTargetNormal)},
   {CC"setCallSiteTargetVolatile", CC"("CS""MH")V",                       FN_PTR(MHN_setCallSiteTargetVolatile)},
-  {CC"invalidateDependentNMethods", CC"("CS")V",                         FN_PTR(MHN_invalidateDependentNMethods)},
+  {CC"clearCallSiteContext",      CC"("CTX")V",                          FN_PTR(MHN_clearCallSiteContext)},
   {CC"staticFieldOffset",         CC"("MEM")J",                          FN_PTR(MHN_staticFieldOffset)},
   {CC"staticFieldBase",           CC"("MEM")"OBJ,                        FN_PTR(MHN_staticFieldBase)},
   {CC"getMemberVMInfo",           CC"("MEM")"OBJ,                        FN_PTR(MHN_getMemberVMInfo)}

hotspot/src/share/vm/prims/methodHandles.hpp

@@ -69,7 +69,10 @@ class MethodHandles: AllStatic {
   enum { _suppress_defc = 1, _suppress_name = 2, _suppress_type = 4 };
 
   // CallSite support
-  static InstanceKlass* get_call_site_context(oop call_site);
+  static void add_dependent_nmethod(oop call_site, nmethod* nm);
+  static void remove_dependent_nmethod(oop call_site, nmethod* nm);
+
+  static void flush_dependent_nmethods(Handle call_site, Handle target);
 
   // Generate MethodHandles adapters.
   static bool generate_adapters();

hotspot/test/compiler/jsr292/CallSiteDepContextTest.java

@@ -24,12 +24,15 @@
 /**
  * @test
  * @bug 8057967
- * @ignore 8079205
+ * @run main/bootclasspath -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:+TraceClassUnloading
- * @run main/bootclasspath -Xbatch java.lang.invoke.CallSiteDepContextTest
+ *                         -XX:+PrintCompilation -XX:+TraceDependencies -XX:+TraceReferenceGC
+ *                         -verbose:gc java.lang.invoke.CallSiteDepContextTest
  */
 package java.lang.invoke;
 
 import java.lang.ref.*;
+import java.lang.reflect.Field;
+
 import jdk.internal.org.objectweb.asm.*;
 import sun.misc.Unsafe;
 
@@ -96,6 +99,13 @@ public class CallSiteDepContextTest {
         }
     }
 
+    public static void testHiddenDepField() throws Exception {
+        try {
+            Field f = MethodHandleNatives.CallSiteContext.class.getDeclaredField("vmdependencies");
+            throw new AssertionError("Context.dependencies field should be hidden");
+        } catch(NoSuchFieldException e) { /* expected */ }
+    }
+
     public static void testSharedCallSite() throws Throwable {
         Class<?> cls1 = UNSAFE.defineAnonymousClass(Object.class, getClassFile("CS_1"), null);
         Class<?> cls2 = UNSAFE.defineAnonymousClass(Object.class, getClassFile("CS_2"), null);
@@ -132,12 +142,14 @@ public class CallSiteDepContextTest {
     static ReferenceQueue rq = new ReferenceQueue();
     static PhantomReference ref;
 
-    public static void testGC() throws Throwable {
+    public static void testGC(boolean clear, boolean precompile) throws Throwable {
+        String id = "_" + clear + "_" + precompile;
+
         mcs = new MutableCallSite(LOOKUP.findStatic(T.class, "f1", TYPE));
 
         Class<?>[] cls = new Class[] {
-                UNSAFE.defineAnonymousClass(Object.class, getClassFile("GC_1"), null),
+                UNSAFE.defineAnonymousClass(Object.class, getClassFile("GC_1" + id), null),
-                UNSAFE.defineAnonymousClass(Object.class, getClassFile("GC_2"), null),
+                UNSAFE.defineAnonymousClass(Object.class, getClassFile("GC_2" + id), null),
         };
 
         MethodHandle[] mhs = new MethodHandle[] {
@@ -151,30 +163,38 @@ public class CallSiteDepContextTest {
         execute(1, mhs);
 
         ref = new PhantomReference<>(cls[0], rq);
-        cls[0] = UNSAFE.defineAnonymousClass(Object.class, getClassFile("GC_3"), null);
+        cls[0] = UNSAFE.defineAnonymousClass(Object.class, getClassFile("GC_3" + id), null);
         mhs[0] = LOOKUP.findStatic(cls[0], METHOD_NAME, TYPE);
 
         do {
             System.gc();
             try {
-                Reference ref1 = rq.remove(1000);
+                Reference ref1 = rq.remove(100);
                 if (ref1 == ref) {
-                    ref1.clear();
-                    System.gc(); // Ensure that the stale context is cleared
                     break;
                 }
             } catch(InterruptedException e) { /* ignore */ }
         } while (true);
 
-        execute(1, mhs);
+        if (clear) {
+            ref.clear();
+            System.gc(); // Ensure that the stale context is unloaded
+        }
+        if (precompile) {
+            execute(1, mhs);
+        }
         mcs.setTarget(LOOKUP.findStatic(T.class, "f2", TYPE));
         execute(2, mhs);
     }
 
     public static void main(String[] args) throws Throwable {
+        testHiddenDepField();
         testSharedCallSite();
         testNonBoundCallSite();
-        testGC();
+        testGC(false, false);
+        testGC(false,  true);
+        testGC( true, false);
+        testGC( true,  true);
         System.out.println("TEST PASSED");
     }
 }