1 /*
   2  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "memory/allocation.inline.hpp"
  27 #include "oops/constantPool.hpp"
  28 #include "oops/oop.inline.hpp"
  29 #include "runtime/atomic.hpp"
  30 #include "runtime/handles.inline.hpp"
  31 #include "runtime/thread.inline.hpp"
  32 
  33 #ifdef ASSERT
  34 oop* HandleArea::allocate_handle(oop obj) {
  35   assert(_handle_mark_nesting > 1, "memory leak: allocating handle outside HandleMark");
  36   assert(_no_handle_mark_nesting == 0, "allocating handle inside NoHandleMark");
  37   assert(oopDesc::is_oop(obj), "not an oop: " INTPTR_FORMAT, p2i(obj));
  38   return real_allocate_handle(obj);
  39 }
  40 #endif
  41 
  42 // Copy constructors and destructors for metadata handles
  43 // These do too much to inline.
  44 #define DEF_METADATA_HANDLE_FN_NOINLINE(name, type) \
  45 name##Handle::name##Handle(const name##Handle &h) {                    \
  46   _value = h._value;                                                   \
  47   if (_value != NULL) {                                                \
  48     assert(_value->is_valid(), "obj is valid");                        \
  49     if (h._thread != NULL) {                                           \
  50       assert(h._thread == Thread::current(), "thread must be current");\
  51       _thread = h._thread;                                             \
  52     } else {                                                           \
  53       _thread = Thread::current();                                     \
  54     }                                                                  \
  55     assert (_thread->is_in_stack((address)this), "not on stack?");     \
  56     _thread->metadata_handles()->push((Metadata*)_value);              \
  57   } else {                                                             \
  58     _thread = NULL;                                                    \
  59   }                                                                    \
  60 }                                                                      \
  61 name##Handle& name##Handle::operator=(const name##Handle &s) {         \
  62   remove();                                                            \
  63   _value = s._value;                                                   \
  64   if (_value != NULL) {                                                \
  65     assert(_value->is_valid(), "obj is valid");                        \
  66     if (s._thread != NULL) {                                           \
  67       assert(s._thread == Thread::current(), "thread must be current");\
  68       _thread = s._thread;                                             \
  69     } else {                                                           \
  70       _thread = Thread::current();                                     \
  71     }                                                                  \
  72     assert (_thread->is_in_stack((address)this), "not on stack?");     \
  73     _thread->metadata_handles()->push((Metadata*)_value);              \
  74   } else {                                                             \
  75     _thread = NULL;                                                    \
  76   }                                                                    \
  77   return *this;                                                        \
  78 }                                                                      \
  79 inline void name##Handle::remove() {                                   \
  80   if (_value != NULL) {                                                \
  81     int i = _thread->metadata_handles()->find_from_end((Metadata*)_value); \
  82     assert(i!=-1, "not in metadata_handles list");                     \
  83     _thread->metadata_handles()->remove_at(i);                         \
  84   }                                                                    \
  85 }                                                                      \
  86 name##Handle::~name##Handle () { remove(); }                           \
  87 
  88 DEF_METADATA_HANDLE_FN_NOINLINE(method, Method)
  89 DEF_METADATA_HANDLE_FN_NOINLINE(constantPool, ConstantPool)
  90 
  91 
  92 static uintx chunk_oops_do(OopClosure* f, Chunk* chunk, char* chunk_top) {
  93   oop* bottom = (oop*) chunk->bottom();
  94   oop* top    = (oop*) chunk_top;
  95   uintx handles_visited = top - bottom;
  96   assert(top >= bottom && top <= (oop*) chunk->top(), "just checking");
  97   // during GC phase 3, a handle may be a forward pointer that
  98   // is not yet valid, so loosen the assertion
  99   while (bottom < top) {
 100     // This test can be moved up but for now check every oop.
 101 
 102     assert(oopDesc::is_oop(*bottom), "handle should point to oop");
 103 
 104     f->do_oop(bottom++);
 105   }
 106   return handles_visited;
 107 }
 108 
 109 // Used for debugging handle allocation.
 110 NOT_PRODUCT(jint _nof_handlemarks  = 0;)
 111 
 112 void HandleArea::oops_do(OopClosure* f) {
 113   uintx handles_visited = 0;
 114   // First handle the current chunk. It is filled to the high water mark.
 115   handles_visited += chunk_oops_do(f, _chunk, _hwm);
 116   // Then handle all previous chunks. They are completely filled.
 117   Chunk* k = _first;
 118   while(k != _chunk) {
 119     handles_visited += chunk_oops_do(f, k, k->top());
 120     k = k->next();
 121   }
 122 
 123   if (_prev != NULL) _prev->oops_do(f);
 124 }
 125 
 126 void HandleMark::initialize(Thread* thread) {
 127   _thread = thread;
 128   // Save area
 129   _area  = thread->handle_area();
 130   // Save current top
 131   _chunk = _area->_chunk;
 132   _hwm   = _area->_hwm;
 133   _max   = _area->_max;
 134   _size_in_bytes = _area->_size_in_bytes;
 135   debug_only(_area->_handle_mark_nesting++);
 136   assert(_area->_handle_mark_nesting > 0, "must stack allocate HandleMarks");
 137   debug_only(Atomic::inc(&_nof_handlemarks);)
 138 
 139   // Link this in the thread
 140   set_previous_handle_mark(thread->last_handle_mark());
 141   thread->set_last_handle_mark(this);
 142 }
 143 
 144 
 145 HandleMark::~HandleMark() {
 146   HandleArea* area = _area;   // help compilers with poor alias analysis
 147   assert(area == _thread->handle_area(), "sanity check");
 148   assert(area->_handle_mark_nesting > 0, "must stack allocate HandleMarks" );
 149   debug_only(area->_handle_mark_nesting--);
 150 
 151   // Delete later chunks
 152   if( _chunk->next() ) {
 153     // reset arena size before delete chunks. Otherwise, the total
 154     // arena size could exceed total chunk size
 155     assert(area->size_in_bytes() > size_in_bytes(), "Sanity check");
 156     area->set_size_in_bytes(size_in_bytes());
 157     _chunk->next_chop();
 158   } else {
 159     assert(area->size_in_bytes() == size_in_bytes(), "Sanity check");
 160   }
 161   // Roll back arena to saved top markers
 162   area->_chunk = _chunk;
 163   area->_hwm = _hwm;
 164   area->_max = _max;
 165 #ifdef ASSERT
 166   // clear out first chunk (to detect allocation bugs)
 167   if (ZapVMHandleArea) {
 168     memset(_hwm, badHandleValue, _max - _hwm);
 169   }
 170   Atomic::dec(&_nof_handlemarks);
 171 #endif
 172 
 173   // Unlink this from the thread
 174   _thread->set_last_handle_mark(previous_handle_mark());
 175 }
 176 
 177 void* HandleMark::operator new(size_t size) throw() {
 178   return AllocateHeap(size, mtThread);
 179 }
 180 
 181 void* HandleMark::operator new [] (size_t size) throw() {
 182   return AllocateHeap(size, mtThread);
 183 }
 184 
 185 void HandleMark::operator delete(void* p) {
 186   FreeHeap(p);
 187 }
 188 
 189 void HandleMark::operator delete[](void* p) {
 190   FreeHeap(p);
 191 }
 192 
 193 #ifdef ASSERT
 194 
 195 NoHandleMark::NoHandleMark() {
 196   HandleArea* area = Thread::current()->handle_area();
 197   area->_no_handle_mark_nesting++;
 198   assert(area->_no_handle_mark_nesting > 0, "must stack allocate NoHandleMark" );
 199 }
 200 
 201 
 202 NoHandleMark::~NoHandleMark() {
 203   HandleArea* area = Thread::current()->handle_area();
 204   assert(area->_no_handle_mark_nesting > 0, "must stack allocate NoHandleMark" );
 205   area->_no_handle_mark_nesting--;
 206 }
 207 
 208 
 209 ResetNoHandleMark::ResetNoHandleMark() {
 210   HandleArea* area = Thread::current()->handle_area();
 211   _no_handle_mark_nesting = area->_no_handle_mark_nesting;
 212   area->_no_handle_mark_nesting = 0;
 213 }
 214 
 215 
 216 ResetNoHandleMark::~ResetNoHandleMark() {
 217   HandleArea* area = Thread::current()->handle_area();
 218   area->_no_handle_mark_nesting = _no_handle_mark_nesting;
 219 }
 220 
 221 #endif