duke@435: /*
duke@435:  * Copyright 1997-2003 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // The resource area holds temporary data structures in the VM.
duke@435: // The actual allocation areas are thread local. Typical usage:
duke@435: //
duke@435: //   ...
duke@435: //   {
duke@435: //     ResourceMark rm;
duke@435: //     int foo[] = NEW_RESOURCE_ARRAY(int, 64);
duke@435: //     ...
duke@435: //   }
duke@435: //   ...
duke@435: 
duke@435: //------------------------------ResourceArea-----------------------------------
duke@435: // A ResourceArea is an Arena that supports safe usage of ResourceMark.
duke@435: class ResourceArea: public Arena {
duke@435:   friend class ResourceMark;
duke@435:   friend class DeoptResourceMark;
duke@435:   debug_only(int _nesting;)             // current # of nested ResourceMarks
duke@435:   debug_only(static int _warned;)       // to suppress multiple warnings
duke@435: 
duke@435: public:
duke@435:   ResourceArea() {
duke@435:     debug_only(_nesting = 0;)
duke@435:   }
duke@435: 
duke@435:   ResourceArea(size_t init_size) : Arena(init_size) {
duke@435:     debug_only(_nesting = 0;);
duke@435:   }
duke@435: 
duke@435:   char* allocate_bytes(size_t size) {
duke@435: #ifdef ASSERT
duke@435:     if (_nesting < 1 && !_warned++)
duke@435:       fatal("memory leak: allocating without ResourceMark");
duke@435:     if (UseMallocOnly) {
duke@435:       // use malloc, but save pointer in res. area for later freeing
duke@435:       char** save = (char**)internal_malloc_4(sizeof(char*));
duke@435:       return (*save = (char*)os::malloc(size));
duke@435:     }
duke@435: #endif
duke@435:     return (char*)Amalloc(size);
duke@435:   }
duke@435: 
duke@435:   debug_only(int nesting() const { return _nesting; });
duke@435: };
duke@435: 
duke@435: 
duke@435: //------------------------------ResourceMark-----------------------------------
duke@435: // A resource mark releases all resources allocated after it was constructed
duke@435: // when the destructor is called.  Typically used as a local variable.
duke@435: class ResourceMark: public StackObj {
duke@435: protected:
duke@435:   ResourceArea *_area;          // Resource area to stack allocate
duke@435:   Chunk *_chunk;                // saved arena chunk
duke@435:   char *_hwm, *_max;
duke@435:   NOT_PRODUCT(size_t _size_in_bytes;)
duke@435: 
duke@435:   void initialize(Thread *thread) {
duke@435:     _area = thread->resource_area();
duke@435:     _chunk = _area->_chunk;
duke@435:     _hwm = _area->_hwm;
duke@435:     _max= _area->_max;
duke@435:     NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
duke@435:     debug_only(_area->_nesting++;)
duke@435:     assert( _area->_nesting > 0, "must stack allocate RMs" );
duke@435:   }
duke@435: 
duke@435:  public:
duke@435: 
duke@435: #ifndef ASSERT
duke@435:   ResourceMark(Thread *thread) {
duke@435:     assert(thread == Thread::current(), "not the current thread");
duke@435:     initialize(thread);
duke@435:   }
duke@435: #else
duke@435:   ResourceMark(Thread *thread);
duke@435: #endif // ASSERT
duke@435: 
duke@435:   ResourceMark()               { initialize(Thread::current()); }
duke@435: 
duke@435:   ResourceMark( ResourceArea *r ) :
duke@435:     _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) {
duke@435:     NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
duke@435:     debug_only(_area->_nesting++;)
duke@435:     assert( _area->_nesting > 0, "must stack allocate RMs" );
duke@435:   }
duke@435: 
duke@435:   void reset_to_mark() {
duke@435:     if (UseMallocOnly) free_malloced_objects();
duke@435: 
duke@435:     if( _chunk->next() )        // Delete later chunks
duke@435:       _chunk->next_chop();
duke@435:     _area->_chunk = _chunk;     // Roll back arena to saved chunk
duke@435:     _area->_hwm = _hwm;
duke@435:     _area->_max = _max;
duke@435: 
duke@435:     // clear out this chunk (to detect allocation bugs)
duke@435:     if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm);
duke@435:     _area->set_size_in_bytes(size_in_bytes());
duke@435:   }
duke@435: 
duke@435:   ~ResourceMark() {
duke@435:     assert( _area->_nesting > 0, "must stack allocate RMs" );
duke@435:     debug_only(_area->_nesting--;)
duke@435:     reset_to_mark();
duke@435:   }
duke@435: 
duke@435: 
duke@435:  private:
duke@435:   void free_malloced_objects()                                         PRODUCT_RETURN;
duke@435:   size_t size_in_bytes()       NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0;
duke@435: };
duke@435: 
duke@435: //------------------------------DeoptResourceMark-----------------------------------
duke@435: // A deopt resource mark releases all resources allocated after it was constructed
duke@435: // when the destructor is called.  Typically used as a local variable. It differs
duke@435: // from a typical resource more in that it is C-Heap allocated so that deoptimization
duke@435: // can use data structures that are arena based but are not amenable to vanilla
duke@435: // ResourceMarks because deoptimization can not use a stack allocated mark. During
duke@435: // deoptimization we go thru the following steps:
duke@435: //
duke@435: // 0: start in assembly stub and call either uncommon_trap/fetch_unroll_info
duke@435: // 1: create the vframeArray (contains pointers to Resource allocated structures)
duke@435: //   This allocates the DeoptResourceMark.
duke@435: // 2: return to assembly stub and remove stub frame and deoptee frame and create
duke@435: //    the new skeletal frames.
duke@435: // 3: push new stub frame and call unpack_frames
duke@435: // 4: retrieve information from the vframeArray to populate the skeletal frames
duke@435: // 5: release the DeoptResourceMark
duke@435: // 6: return to stub and eventually to interpreter
duke@435: //
duke@435: // With old style eager deoptimization the vframeArray was created by the vmThread there
duke@435: // was no way for the vframeArray to contain resource allocated objects and so
duke@435: // a complex set of data structures to simulate an array of vframes in CHeap memory
duke@435: // was used. With new style lazy deoptimization the vframeArray is created in the
duke@435: // the thread that will use it and we can use a much simpler scheme for the vframeArray
duke@435: // leveraging existing data structures if we simply create a way to manage this one
duke@435: // special need for a ResourceMark. If ResourceMark simply inherited from CHeapObj
duke@435: // then existing ResourceMarks would work fine since no one use new to allocate them
duke@435: // and they would be stack allocated. This leaves open the possibilty of accidental
duke@435: // misuse so we simple duplicate the ResourceMark functionality here.
duke@435: 
duke@435: class DeoptResourceMark: public CHeapObj {
duke@435: protected:
duke@435:   ResourceArea *_area;          // Resource area to stack allocate
duke@435:   Chunk *_chunk;                // saved arena chunk
duke@435:   char *_hwm, *_max;
duke@435:   NOT_PRODUCT(size_t _size_in_bytes;)
duke@435: 
duke@435:   void initialize(Thread *thread) {
duke@435:     _area = thread->resource_area();
duke@435:     _chunk = _area->_chunk;
duke@435:     _hwm = _area->_hwm;
duke@435:     _max= _area->_max;
duke@435:     NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
duke@435:     debug_only(_area->_nesting++;)
duke@435:     assert( _area->_nesting > 0, "must stack allocate RMs" );
duke@435:   }
duke@435: 
duke@435:  public:
duke@435: 
duke@435: #ifndef ASSERT
duke@435:   DeoptResourceMark(Thread *thread) {
duke@435:     assert(thread == Thread::current(), "not the current thread");
duke@435:     initialize(thread);
duke@435:   }
duke@435: #else
duke@435:   DeoptResourceMark(Thread *thread);
duke@435: #endif // ASSERT
duke@435: 
duke@435:   DeoptResourceMark()               { initialize(Thread::current()); }
duke@435: 
duke@435:   DeoptResourceMark( ResourceArea *r ) :
duke@435:     _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) {
duke@435:     NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
duke@435:     debug_only(_area->_nesting++;)
duke@435:     assert( _area->_nesting > 0, "must stack allocate RMs" );
duke@435:   }
duke@435: 
duke@435:   void reset_to_mark() {
duke@435:     if (UseMallocOnly) free_malloced_objects();
duke@435: 
duke@435:     if( _chunk->next() )        // Delete later chunks
duke@435:       _chunk->next_chop();
duke@435:     _area->_chunk = _chunk;     // Roll back arena to saved chunk
duke@435:     _area->_hwm = _hwm;
duke@435:     _area->_max = _max;
duke@435: 
duke@435:     // clear out this chunk (to detect allocation bugs)
duke@435:     if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm);
duke@435:     _area->set_size_in_bytes(size_in_bytes());
duke@435:   }
duke@435: 
duke@435:   ~DeoptResourceMark() {
duke@435:     assert( _area->_nesting > 0, "must stack allocate RMs" );
duke@435:     debug_only(_area->_nesting--;)
duke@435:     reset_to_mark();
duke@435:   }
duke@435: 
duke@435: 
duke@435:  private:
duke@435:   void free_malloced_objects()                                         PRODUCT_RETURN;
duke@435:   size_t size_in_bytes()       NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0;
duke@435: };