complete impl for frames hidden from JVMTI while in VTMT

Author: sspitsyn

src/hotspot/share/classfile/classFileParser.cpp

@@ -1088,6 +1088,7 @@ class AnnotationCollector : public ResourceObj{
     _method_ForceInline,
     _method_DontInline,
     _method_ChangesCurrentThread,
+    _method_JvmtiMountTransition,
     _method_InjectedProfile,
     _method_LambdaForm_Compiled,
     _method_Hidden,
@@ -2114,6 +2115,11 @@ AnnotationCollector::annotation_index(const ClassLoaderData* loader_data,
       if (!privileged)              break;  // only allow in privileged code
       return _method_ChangesCurrentThread;
     }
+    case VM_SYMBOL_ENUM_NAME(jdk_internal_vm_annotation_JvmtiMountTransition_signature): {
+      if (_location != _in_method)  break;  // only allow for methods
+      if (!privileged)              break;  // only allow in privileged code
+      return _method_JvmtiMountTransition;
+    }
     case VM_SYMBOL_ENUM_NAME(java_lang_invoke_InjectedProfile_signature): {
       if (_location != _in_method)  break;  // only allow for methods
       if (!privileged)              break;  // only allow in privileged code
@@ -2192,6 +2198,8 @@ void MethodAnnotationCollector::apply_to(const methodHandle& m) {
     m->set_dont_inline(true);
   if (has_annotation(_method_ChangesCurrentThread))
     m->set_changes_current_thread(true);
+  if (has_annotation(_method_JvmtiMountTransition))
+    m->set_jvmti_mount_transition(true);
   if (has_annotation(_method_InjectedProfile))
     m->set_has_injected_profile(true);
   if (has_annotation(_method_LambdaForm_Compiled) && m->intrinsic_id() == vmIntrinsics::_none)

src/hotspot/share/classfile/vmSymbols.hpp

@@ -317,6 +317,7 @@
   template(jdk_internal_vm_annotation_Stable_signature,      "Ljdk/internal/vm/annotation/Stable;") \
                                                                                                   \
   template(jdk_internal_vm_annotation_ChangesCurrentThread_signature,  "Ljdk/internal/vm/annotation/ChangesCurrentThread;")  \
+  template(jdk_internal_vm_annotation_JvmtiMountTransition_signature,  "Ljdk/internal/vm/annotation/JvmtiMountTransition;")  \
                                                                                                   \
   /* Support for JSR 292 & invokedynamic (JDK 1.7 and above) */                                   \
   template(java_lang_invoke_CallSite,                 "java/lang/invoke/CallSite")                \

src/hotspot/share/oops/method.hpp

@@ -94,6 +94,7 @@ class Method : public Metadata {
     _reserved_stack_access = 1 << 7,
     _scoped                = 1 << 8,
     _changes_current_thread = 1 << 9,
+    _jvmti_mount_transition = 1 << 10,
   };
   mutable u2 _flags;
 
@@ -891,6 +892,13 @@ class Method : public Metadata {
     _flags = x ? (_flags | _changes_current_thread) : (_flags & ~_changes_current_thread);
   }
 
+  bool jvmti_mount_transition() {
+    return (_flags & _jvmti_mount_transition) != 0;
+  }
+  void set_jvmti_mount_transition(bool x) {
+    _flags = x ? (_flags | _jvmti_mount_transition) : (_flags & ~_jvmti_mount_transition);
+  }
+
   bool is_hidden() const {
     return (_flags & _hidden) != 0;
   }

src/hotspot/share/prims/jvmtiEnvBase.cpp

@@ -612,9 +612,10 @@ JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd
 
 javaVFrame*
 JvmtiEnvBase::skip_hidden_frames(javaVFrame* jvf) {
-  // find the top-most jvf with an annotated method
+  // find jvf with a method annotated with @JvmtiMountTransition
   for ( ; jvf != NULL; jvf = jvf->java_sender()) {
-    if (jvf->method()->changes_current_thread()) {
+    if (jvf->method()->jvmti_mount_transition()) {
+      jvf = jvf->java_sender(); // skip annotated method
       break;
     }
   }

src/hotspot/share/prims/jvmtiExport.cpp

@@ -1812,12 +1812,12 @@ void JvmtiExport::post_method_entry(JavaThread *thread, Method* method, frame cu
     // for any thread that actually wants method entry, interp_only_mode is set
     return;
   }
+  if (mh->jvmti_mount_transition() || thread->is_in_VTMT()) {
+    return; // no events should be posted if thread is in a VTMT transition
+  }
 
   state->incr_cur_stack_depth();
 
-  if (thread->is_in_VTMT()) {
-    return; // no events should be posted if thread is in a VTMT transition
-  }
   if (state->is_enabled(JVMTI_EVENT_METHOD_ENTRY)) {
     JvmtiEnvThreadStateIterator it(state);
     for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
@@ -1849,8 +1849,7 @@ void JvmtiExport::post_method_exit(JavaThread* thread, Method* method, frame cur
     // for any thread that actually wants method exit, interp_only_mode is set
     return;
   }
-  if (thread->is_in_VTMT()) {
-    state->decr_cur_stack_depth();
+  if (mh->jvmti_mount_transition() || thread->is_in_VTMT()) {
     return; // no events should be posted if thread is in a VTMT transition
   }
 

src/java.base/share/classes/java/lang/VirtualThread.java

@@ -51,6 +51,7 @@
 import jdk.internal.misc.Unsafe;
 import jdk.internal.vm.ThreadDumper;
 import jdk.internal.vm.annotation.ChangesCurrentThread;
+import jdk.internal.vm.annotation.JvmtiMountTransition;
 import sun.nio.ch.Interruptible;
 import sun.security.action.GetPropertyAction;
 import static java.util.concurrent.TimeUnit.*;
@@ -920,10 +921,19 @@ private boolean getAndSetParkPermit(boolean newValue) {
     // -- JVM TI support --
 
     private static volatile boolean notifyJvmtiEvents;  // set by VM
+
+    @JvmtiMountTransition
     private native void notifyJvmtiMountBegin(boolean firstMount);
+
+    @JvmtiMountTransition
     private native void notifyJvmtiMountEnd(boolean firstMount);
+
+    @JvmtiMountTransition
     private native void notifyJvmtiUnmountBegin();
+
+    @JvmtiMountTransition
     private native void notifyJvmtiUnmountEnd();
+
     private native void notifyJvmtiTerminated();
     private static native void registerNatives();
     static {

src/java.base/share/classes/jdk/internal/vm/annotation/JvmtiMountTransition.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.internal.vm.annotation;
+
+import java.lang.annotation.*;
+
+/**
+ * A method is annotated as "jvmti mount transition" if it starts
+ * or ends virtual thread mount transition (VTMT).
+ *
+ * @implNote
+ * This annotation is only used for VirtualThread methods.
+ */
+@Target({ElementType.METHOD})
+@Retention(RetentionPolicy.RUNTIME)
+public @interface JvmtiMountTransition {
+}