8258015: [JVMCI] JVMCI_lock shouldn't be held while initializing box …

…classes

Reviewed-by: iveresov

src/hotspot/share/jvmci/jvmci.cpp

@@ -37,7 +37,7 @@
 JVMCIRuntime* JVMCI::_compiler_runtime = NULL;
 JVMCIRuntime* JVMCI::_java_runtime = NULL;
 volatile bool JVMCI::_is_initialized = false;
-volatile bool JVMCI::_box_caches_initialized = false;
+bool JVMCI::_box_caches_initialized = false;
 void* JVMCI::_shared_library_handle = NULL;
 char* JVMCI::_shared_library_path = NULL;
 volatile bool JVMCI::_in_shutdown = false;
@@ -130,12 +130,9 @@ void JVMCI::ensure_box_caches_initialized(TRAPS) {
   if (_box_caches_initialized) {
     return;
   }
-  MutexLocker locker(JVMCI_lock);
-  // Check again after locking
-  if (_box_caches_initialized) {
-    return;
-  }
 
+  // While multiple threads may reach here, that's fine
+  // since class initialization is synchronized.
   Symbol* box_classes[] = {
     java_lang_Boolean::symbol(),
     java_lang_Byte_ByteCache::symbol(),

src/hotspot/share/jvmci/jvmci.hpp

@@ -53,8 +53,8 @@ class JVMCI : public AllStatic {
   // execution has completed successfully.
   static volatile bool _is_initialized;
 
-  // used to synchronize lazy initialization of boxing cache classes.
-  static volatile bool _box_caches_initialized;
+  // True once boxing cache classes are guaranteed to be initialized.
+  static bool _box_caches_initialized;
 
   // Handle created when loading the JVMCI shared library with os::dll_load.
   // Must hold JVMCI_lock when initializing.

src/hotspot/share/jvmci/jvmciCodeInstaller.cpp

@@ -945,6 +945,10 @@ JVMCI::CodeInstallResult CodeInstaller::initialize_buffer(CodeBuffer& buffer, bo
     }
   }
 #endif
+  if (_has_auto_box) {
+    JavaThread* THREAD = JavaThread::current();
+    JVMCI::ensure_box_caches_initialized(CHECK_(JVMCI::ok));
+  }
   return JVMCI::ok;
 }
 
@@ -1022,15 +1026,14 @@ GrowableArray<ScopeValue*>* CodeInstaller::record_virtual_objects(JVMCIObject de
   }
   GrowableArray<ScopeValue*>* objects = new GrowableArray<ScopeValue*>(JVMCIENV->get_length(virtualObjects), JVMCIENV->get_length(virtualObjects), NULL);
   // Create the unique ObjectValues
-  bool has_auto_box = false;
   for (int i = 0; i < JVMCIENV->get_length(virtualObjects); i++) {
     // HandleMark hm(THREAD);
     JVMCIObject value = JVMCIENV->get_object_at(virtualObjects, i);
     int id = jvmci_env()->get_VirtualObject_id(value);
     JVMCIObject type = jvmci_env()->get_VirtualObject_type(value);
     bool is_auto_box = jvmci_env()->get_VirtualObject_isAutoBox(value);
     if (is_auto_box) {
-      has_auto_box = true;
+      _has_auto_box = true;
     }
     Klass* klass = jvmci_env()->asKlass(type);
     oop javaMirror = klass->java_mirror();
@@ -1054,10 +1057,6 @@ GrowableArray<ScopeValue*>* CodeInstaller::record_virtual_objects(JVMCIObject de
   }
   _debug_recorder->dump_object_pool(objects);
 
-  if (has_auto_box) {
-    JavaThread* THREAD = JavaThread::current();
-    JVMCI::ensure_box_caches_initialized(CHECK_NULL);
-  }
   return objects;
 }
 

src/hotspot/share/jvmci/jvmciCodeInstaller.hpp

@@ -200,6 +200,7 @@ class CodeInstaller : public StackObj {
   Dependencies*             _dependencies;
   ExceptionHandlerTable     _exception_handler_table;
   ImplicitExceptionTable    _implicit_exception_table;
+  bool                      _has_auto_box;
 
   bool _immutable_pic_compilation;  // Installer is called for Immutable PIC compilation.
 
@@ -230,7 +231,11 @@ class CodeInstaller : public StackObj {
 
 public:
 
-  CodeInstaller(JVMCIEnv* jvmci_env, bool immutable_pic_compilation) : _arena(mtJVMCI), _jvmci_env(jvmci_env), _immutable_pic_compilation(immutable_pic_compilation) {}
+  CodeInstaller(JVMCIEnv* jvmci_env, bool immutable_pic_compilation) :
+    _arena(mtJVMCI),
+    _jvmci_env(jvmci_env),
+    _has_auto_box(false),
+    _immutable_pic_compilation(immutable_pic_compilation) {}
 
 #if INCLUDE_AOT
   JVMCI::CodeInstallResult gather_metadata(JVMCIObject target, JVMCIObject compiled_code, CodeMetadata& metadata, JVMCI_TRAPS);