1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/resourceArea.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,226 @@
1.4 +/*
1.5 + * Copyright 1997-2003 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +// The resource area holds temporary data structures in the VM.
1.29 +// The actual allocation areas are thread local. Typical usage:
1.30 +//
1.31 +// ...
1.32 +// {
1.33 +// ResourceMark rm;
1.34 +// int foo[] = NEW_RESOURCE_ARRAY(int, 64);
1.35 +// ...
1.36 +// }
1.37 +// ...
1.38 +
1.39 +//------------------------------ResourceArea-----------------------------------
1.40 +// A ResourceArea is an Arena that supports safe usage of ResourceMark.
1.41 +class ResourceArea: public Arena {
1.42 + friend class ResourceMark;
1.43 + friend class DeoptResourceMark;
1.44 + debug_only(int _nesting;) // current # of nested ResourceMarks
1.45 + debug_only(static int _warned;) // to suppress multiple warnings
1.46 +
1.47 +public:
1.48 + ResourceArea() {
1.49 + debug_only(_nesting = 0;)
1.50 + }
1.51 +
1.52 + ResourceArea(size_t init_size) : Arena(init_size) {
1.53 + debug_only(_nesting = 0;);
1.54 + }
1.55 +
1.56 + char* allocate_bytes(size_t size) {
1.57 +#ifdef ASSERT
1.58 + if (_nesting < 1 && !_warned++)
1.59 + fatal("memory leak: allocating without ResourceMark");
1.60 + if (UseMallocOnly) {
1.61 + // use malloc, but save pointer in res. area for later freeing
1.62 + char** save = (char**)internal_malloc_4(sizeof(char*));
1.63 + return (*save = (char*)os::malloc(size));
1.64 + }
1.65 +#endif
1.66 + return (char*)Amalloc(size);
1.67 + }
1.68 +
1.69 + debug_only(int nesting() const { return _nesting; });
1.70 +};
1.71 +
1.72 +
1.73 +//------------------------------ResourceMark-----------------------------------
1.74 +// A resource mark releases all resources allocated after it was constructed
1.75 +// when the destructor is called. Typically used as a local variable.
1.76 +class ResourceMark: public StackObj {
1.77 +protected:
1.78 + ResourceArea *_area; // Resource area to stack allocate
1.79 + Chunk *_chunk; // saved arena chunk
1.80 + char *_hwm, *_max;
1.81 + NOT_PRODUCT(size_t _size_in_bytes;)
1.82 +
1.83 + void initialize(Thread *thread) {
1.84 + _area = thread->resource_area();
1.85 + _chunk = _area->_chunk;
1.86 + _hwm = _area->_hwm;
1.87 + _max= _area->_max;
1.88 + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
1.89 + debug_only(_area->_nesting++;)
1.90 + assert( _area->_nesting > 0, "must stack allocate RMs" );
1.91 + }
1.92 +
1.93 + public:
1.94 +
1.95 +#ifndef ASSERT
1.96 + ResourceMark(Thread *thread) {
1.97 + assert(thread == Thread::current(), "not the current thread");
1.98 + initialize(thread);
1.99 + }
1.100 +#else
1.101 + ResourceMark(Thread *thread);
1.102 +#endif // ASSERT
1.103 +
1.104 + ResourceMark() { initialize(Thread::current()); }
1.105 +
1.106 + ResourceMark( ResourceArea *r ) :
1.107 + _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) {
1.108 + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
1.109 + debug_only(_area->_nesting++;)
1.110 + assert( _area->_nesting > 0, "must stack allocate RMs" );
1.111 + }
1.112 +
1.113 + void reset_to_mark() {
1.114 + if (UseMallocOnly) free_malloced_objects();
1.115 +
1.116 + if( _chunk->next() ) // Delete later chunks
1.117 + _chunk->next_chop();
1.118 + _area->_chunk = _chunk; // Roll back arena to saved chunk
1.119 + _area->_hwm = _hwm;
1.120 + _area->_max = _max;
1.121 +
1.122 + // clear out this chunk (to detect allocation bugs)
1.123 + if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm);
1.124 + _area->set_size_in_bytes(size_in_bytes());
1.125 + }
1.126 +
1.127 + ~ResourceMark() {
1.128 + assert( _area->_nesting > 0, "must stack allocate RMs" );
1.129 + debug_only(_area->_nesting--;)
1.130 + reset_to_mark();
1.131 + }
1.132 +
1.133 +
1.134 + private:
1.135 + void free_malloced_objects() PRODUCT_RETURN;
1.136 + size_t size_in_bytes() NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0;
1.137 +};
1.138 +
1.139 +//------------------------------DeoptResourceMark-----------------------------------
1.140 +// A deopt resource mark releases all resources allocated after it was constructed
1.141 +// when the destructor is called. Typically used as a local variable. It differs
1.142 +// from a typical resource more in that it is C-Heap allocated so that deoptimization
1.143 +// can use data structures that are arena based but are not amenable to vanilla
1.144 +// ResourceMarks because deoptimization can not use a stack allocated mark. During
1.145 +// deoptimization we go thru the following steps:
1.146 +//
1.147 +// 0: start in assembly stub and call either uncommon_trap/fetch_unroll_info
1.148 +// 1: create the vframeArray (contains pointers to Resource allocated structures)
1.149 +// This allocates the DeoptResourceMark.
1.150 +// 2: return to assembly stub and remove stub frame and deoptee frame and create
1.151 +// the new skeletal frames.
1.152 +// 3: push new stub frame and call unpack_frames
1.153 +// 4: retrieve information from the vframeArray to populate the skeletal frames
1.154 +// 5: release the DeoptResourceMark
1.155 +// 6: return to stub and eventually to interpreter
1.156 +//
1.157 +// With old style eager deoptimization the vframeArray was created by the vmThread there
1.158 +// was no way for the vframeArray to contain resource allocated objects and so
1.159 +// a complex set of data structures to simulate an array of vframes in CHeap memory
1.160 +// was used. With new style lazy deoptimization the vframeArray is created in the
1.161 +// the thread that will use it and we can use a much simpler scheme for the vframeArray
1.162 +// leveraging existing data structures if we simply create a way to manage this one
1.163 +// special need for a ResourceMark. If ResourceMark simply inherited from CHeapObj
1.164 +// then existing ResourceMarks would work fine since no one use new to allocate them
1.165 +// and they would be stack allocated. This leaves open the possibilty of accidental
1.166 +// misuse so we simple duplicate the ResourceMark functionality here.
1.167 +
1.168 +class DeoptResourceMark: public CHeapObj {
1.169 +protected:
1.170 + ResourceArea *_area; // Resource area to stack allocate
1.171 + Chunk *_chunk; // saved arena chunk
1.172 + char *_hwm, *_max;
1.173 + NOT_PRODUCT(size_t _size_in_bytes;)
1.174 +
1.175 + void initialize(Thread *thread) {
1.176 + _area = thread->resource_area();
1.177 + _chunk = _area->_chunk;
1.178 + _hwm = _area->_hwm;
1.179 + _max= _area->_max;
1.180 + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
1.181 + debug_only(_area->_nesting++;)
1.182 + assert( _area->_nesting > 0, "must stack allocate RMs" );
1.183 + }
1.184 +
1.185 + public:
1.186 +
1.187 +#ifndef ASSERT
1.188 + DeoptResourceMark(Thread *thread) {
1.189 + assert(thread == Thread::current(), "not the current thread");
1.190 + initialize(thread);
1.191 + }
1.192 +#else
1.193 + DeoptResourceMark(Thread *thread);
1.194 +#endif // ASSERT
1.195 +
1.196 + DeoptResourceMark() { initialize(Thread::current()); }
1.197 +
1.198 + DeoptResourceMark( ResourceArea *r ) :
1.199 + _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) {
1.200 + NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();)
1.201 + debug_only(_area->_nesting++;)
1.202 + assert( _area->_nesting > 0, "must stack allocate RMs" );
1.203 + }
1.204 +
1.205 + void reset_to_mark() {
1.206 + if (UseMallocOnly) free_malloced_objects();
1.207 +
1.208 + if( _chunk->next() ) // Delete later chunks
1.209 + _chunk->next_chop();
1.210 + _area->_chunk = _chunk; // Roll back arena to saved chunk
1.211 + _area->_hwm = _hwm;
1.212 + _area->_max = _max;
1.213 +
1.214 + // clear out this chunk (to detect allocation bugs)
1.215 + if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm);
1.216 + _area->set_size_in_bytes(size_in_bytes());
1.217 + }
1.218 +
1.219 + ~DeoptResourceMark() {
1.220 + assert( _area->_nesting > 0, "must stack allocate RMs" );
1.221 + debug_only(_area->_nesting--;)
1.222 + reset_to_mark();
1.223 + }
1.224 +
1.225 +
1.226 + private:
1.227 + void free_malloced_objects() PRODUCT_RETURN;
1.228 + size_t size_in_bytes() NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0;
1.229 +};
