8043224: -Xcheck:jni improvements to exception checking and excessive local refs

Summary: Warning when not checking exceptions from function that require so, also when local refs expand beyond capacity.
Reviewed-by: dsimms

src/share/vm/memory/guardedMemory.hpp

 /*
- * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 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
@@ -235,7 +235,7 @@ protected:
    * @return the size of the user data.
    */
   size_t get_user_size() const {
-    assert(_base_addr, "Not wrapping any memory");
+    assert(_base_addr != NULL, "Not wrapping any memory");
     return get_head_guard()->get_user_size();
   }
 
@@ -245,7 +245,7 @@ protected:
    * @return the user data pointer.
    */
   u_char* get_user_ptr() const {
-    assert(_base_addr, "Not wrapping any memory");
+    assert(_base_addr != NULL, "Not wrapping any memory");
     return _base_addr + sizeof(GuardHeader);
   }
 
@@ -281,7 +281,7 @@ protected:
     memset(get_user_ptr(), ch, get_user_size());
   }
 
-public:
+ public:
   /**
    * Return the total size required for wrapping the given user size.
    *

src/share/vm/runtime/jniHandles.cpp

 /*
- * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2015, 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
@@ -296,6 +296,7 @@ JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread)  {
   block->_top  = 0;
   block->_next = NULL;
   block->_pop_frame_link = NULL;
+  block->_planned_capacity = block_size_in_oops;
   // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle
   debug_only(block->_last = NULL);
   debug_only(block->_free_list = NULL);
@@ -529,6 +530,12 @@ int JNIHandleBlock::length() const {
   return result;
 }
 
+const size_t JNIHandleBlock::get_number_of_live_handles() {
+  CountHandleClosure counter;
+  oops_do(&counter);
+  return counter.count();
+}
+
 // This method is not thread-safe, i.e., must be called whule holding a lock on the
 // structure.
 long JNIHandleBlock::memory_usage() const {

src/share/vm/runtime/jniHandles.hpp

 /*
- * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2015, 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
@@ -112,6 +112,9 @@ class JNIHandleBlock : public CHeapObj<mtInternal> {
   oop*            _free_list;                   // Handle free list
   int             _allocate_before_rebuild;     // Number of blocks to allocate before rebuilding free list
 
+  // Check JNI, "planned capacity" for current frame (or push/ensure)
+  size_t          _planned_capacity;
+
   #ifndef PRODUCT
   JNIHandleBlock* _block_list_link;             // Link for list below
   static JNIHandleBlock* _block_list;           // List of all allocated blocks (for debugging only)
@@ -152,6 +155,11 @@ class JNIHandleBlock : public CHeapObj<mtInternal> {
   // Traversal of weak handles. Unreachable oops are cleared.
   void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f);
 
+  // Checked JNI support
+  void set_planned_capacity(size_t planned_capacity) { _planned_capacity = planned_capacity; }
+  const size_t get_planned_capacity() { return _planned_capacity; }
+  const size_t get_number_of_live_handles();
+
   // Debugging
   bool chain_contains(jobject handle) const;    // Does this block or following blocks contain handle
   bool contains(jobject handle) const;          // Does this block contain handle

src/share/vm/runtime/thread.cpp

 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2015, 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
@@ -1465,6 +1465,7 @@ void JavaThread::initialize() {
   _thread_stat = new ThreadStatistics();
   _blocked_on_compilation = false;
   _jni_active_critical = 0;
+  _pending_jni_exception_check_fn = NULL;
   _do_not_unlock_if_synchronized = false;
   _cached_monitor_info = NULL;
   _parker = Parker::Allocate(this) ;

src/share/vm/runtime/thread.hpp

 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2015, 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
@@ -926,6 +926,9 @@ class JavaThread: public Thread {
   // support for JNI critical regions
   jint    _jni_active_critical;                  // count of entries into JNI critical region
 
+  // Checked JNI: function name requires exception check
+  char* _pending_jni_exception_check_fn;
+
   // For deadlock detection.
   int _depth_first_number;
 
@@ -1408,6 +1411,12 @@ class JavaThread: public Thread {
                           assert(_jni_active_critical >= 0,
                                  "JNI critical nesting problem?"); }
 
+  // Checked JNI, is the programmer required to check for exceptions, specify which function name
+  bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
+  void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
+  const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
+  void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
+
   // For deadlock detection
   int depth_first_number() { return _depth_first_number; }
   void set_depth_first_number(int dfn) { _depth_first_number = dfn; }