diff -r 000000000000 -r a61af66fc99e src/share/vm/memory/resourceArea.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/resourceArea.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,226 @@ +/* + * Copyright 1997-2003 Sun Microsystems, Inc. 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. + * + * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// The resource area holds temporary data structures in the VM. +// The actual allocation areas are thread local. Typical usage: +// +// ... +// { +// ResourceMark rm; +// int foo[] = NEW_RESOURCE_ARRAY(int, 64); +// ... +// } +// ... + +//------------------------------ResourceArea----------------------------------- +// A ResourceArea is an Arena that supports safe usage of ResourceMark. +class ResourceArea: public Arena { + friend class ResourceMark; + friend class DeoptResourceMark; + debug_only(int _nesting;) // current # of nested ResourceMarks + debug_only(static int _warned;) // to suppress multiple warnings + +public: + ResourceArea() { + debug_only(_nesting = 0;) + } + + ResourceArea(size_t init_size) : Arena(init_size) { + debug_only(_nesting = 0;); + } + + char* allocate_bytes(size_t size) { +#ifdef ASSERT + if (_nesting < 1 && !_warned++) + fatal("memory leak: allocating without ResourceMark"); + if (UseMallocOnly) { + // use malloc, but save pointer in res. area for later freeing + char** save = (char**)internal_malloc_4(sizeof(char*)); + return (*save = (char*)os::malloc(size)); + } +#endif + return (char*)Amalloc(size); + } + + debug_only(int nesting() const { return _nesting; }); +}; + + +//------------------------------ResourceMark----------------------------------- +// A resource mark releases all resources allocated after it was constructed +// when the destructor is called. Typically used as a local variable. +class ResourceMark: public StackObj { +protected: + ResourceArea *_area; // Resource area to stack allocate + Chunk *_chunk; // saved arena chunk + char *_hwm, *_max; + NOT_PRODUCT(size_t _size_in_bytes;) + + void initialize(Thread *thread) { + _area = thread->resource_area(); + _chunk = _area->_chunk; + _hwm = _area->_hwm; + _max= _area->_max; + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) + debug_only(_area->_nesting++;) + assert( _area->_nesting > 0, "must stack allocate RMs" ); + } + + public: + +#ifndef ASSERT + ResourceMark(Thread *thread) { + assert(thread == Thread::current(), "not the current thread"); + initialize(thread); + } +#else + ResourceMark(Thread *thread); +#endif // ASSERT + + ResourceMark() { initialize(Thread::current()); } + + ResourceMark( ResourceArea *r ) : + _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) { + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) + debug_only(_area->_nesting++;) + assert( _area->_nesting > 0, "must stack allocate RMs" ); + } + + void reset_to_mark() { + if (UseMallocOnly) free_malloced_objects(); + + if( _chunk->next() ) // Delete later chunks + _chunk->next_chop(); + _area->_chunk = _chunk; // Roll back arena to saved chunk + _area->_hwm = _hwm; + _area->_max = _max; + + // clear out this chunk (to detect allocation bugs) + if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm); + _area->set_size_in_bytes(size_in_bytes()); + } + + ~ResourceMark() { + assert( _area->_nesting > 0, "must stack allocate RMs" ); + debug_only(_area->_nesting--;) + reset_to_mark(); + } + + + private: + void free_malloced_objects() PRODUCT_RETURN; + size_t size_in_bytes() NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0; +}; + +//------------------------------DeoptResourceMark----------------------------------- +// A deopt resource mark releases all resources allocated after it was constructed +// when the destructor is called. Typically used as a local variable. It differs +// from a typical resource more in that it is C-Heap allocated so that deoptimization +// can use data structures that are arena based but are not amenable to vanilla +// ResourceMarks because deoptimization can not use a stack allocated mark. During +// deoptimization we go thru the following steps: +// +// 0: start in assembly stub and call either uncommon_trap/fetch_unroll_info +// 1: create the vframeArray (contains pointers to Resource allocated structures) +// This allocates the DeoptResourceMark. +// 2: return to assembly stub and remove stub frame and deoptee frame and create +// the new skeletal frames. +// 3: push new stub frame and call unpack_frames +// 4: retrieve information from the vframeArray to populate the skeletal frames +// 5: release the DeoptResourceMark +// 6: return to stub and eventually to interpreter +// +// With old style eager deoptimization the vframeArray was created by the vmThread there +// was no way for the vframeArray to contain resource allocated objects and so +// a complex set of data structures to simulate an array of vframes in CHeap memory +// was used. With new style lazy deoptimization the vframeArray is created in the +// the thread that will use it and we can use a much simpler scheme for the vframeArray +// leveraging existing data structures if we simply create a way to manage this one +// special need for a ResourceMark. If ResourceMark simply inherited from CHeapObj +// then existing ResourceMarks would work fine since no one use new to allocate them +// and they would be stack allocated. This leaves open the possibilty of accidental +// misuse so we simple duplicate the ResourceMark functionality here. + +class DeoptResourceMark: public CHeapObj { +protected: + ResourceArea *_area; // Resource area to stack allocate + Chunk *_chunk; // saved arena chunk + char *_hwm, *_max; + NOT_PRODUCT(size_t _size_in_bytes;) + + void initialize(Thread *thread) { + _area = thread->resource_area(); + _chunk = _area->_chunk; + _hwm = _area->_hwm; + _max= _area->_max; + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) + debug_only(_area->_nesting++;) + assert( _area->_nesting > 0, "must stack allocate RMs" ); + } + + public: + +#ifndef ASSERT + DeoptResourceMark(Thread *thread) { + assert(thread == Thread::current(), "not the current thread"); + initialize(thread); + } +#else + DeoptResourceMark(Thread *thread); +#endif // ASSERT + + DeoptResourceMark() { initialize(Thread::current()); } + + DeoptResourceMark( ResourceArea *r ) : + _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) { + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) + debug_only(_area->_nesting++;) + assert( _area->_nesting > 0, "must stack allocate RMs" ); + } + + void reset_to_mark() { + if (UseMallocOnly) free_malloced_objects(); + + if( _chunk->next() ) // Delete later chunks + _chunk->next_chop(); + _area->_chunk = _chunk; // Roll back arena to saved chunk + _area->_hwm = _hwm; + _area->_max = _max; + + // clear out this chunk (to detect allocation bugs) + if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm); + _area->set_size_in_bytes(size_in_bytes()); + } + + ~DeoptResourceMark() { + assert( _area->_nesting > 0, "must stack allocate RMs" ); + debug_only(_area->_nesting--;) + reset_to_mark(); + } + + + private: + void free_malloced_objects() PRODUCT_RETURN; + size_t size_in_bytes() NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0; +};