1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/code/stubs.cpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,254 @@
1.4 +/*
1.5 + * Copyright 1997-2005 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 +#include "incls/_precompiled.incl"
1.29 +#include "incls/_stubs.cpp.incl"
1.30 +
1.31 +
1.32 +// Implementation of StubQueue
1.33 +//
1.34 +// Standard wrap-around queue implementation; the queue dimensions
1.35 +// are specified by the _queue_begin & _queue_end indices. The queue
1.36 +// can be in two states (transparent to the outside):
1.37 +//
1.38 +// a) contiguous state: all queue entries in one block (or empty)
1.39 +//
1.40 +// Queue: |...|XXXXXXX|...............|
1.41 +// ^0 ^begin ^end ^size = limit
1.42 +// |_______|
1.43 +// one block
1.44 +//
1.45 +// b) non-contiguous state: queue entries in two blocks
1.46 +//
1.47 +// Queue: |XXX|.......|XXXXXXX|.......|
1.48 +// ^0 ^end ^begin ^limit ^size
1.49 +// |___| |_______|
1.50 +// 1st block 2nd block
1.51 +//
1.52 +// In the non-contiguous state, the wrap-around point is
1.53 +// indicated via the _buffer_limit index since the last
1.54 +// queue entry may not fill up the queue completely in
1.55 +// which case we need to know where the 2nd block's end
1.56 +// is to do the proper wrap-around. When removing the
1.57 +// last entry of the 2nd block, _buffer_limit is reset
1.58 +// to _buffer_size.
1.59 +//
1.60 +// CAUTION: DO NOT MESS WITH THIS CODE IF YOU CANNOT PROVE
1.61 +// ITS CORRECTNESS! THIS CODE IS MORE SUBTLE THAN IT LOOKS!
1.62 +
1.63 +
1.64 +StubQueue::StubQueue(StubInterface* stub_interface, int buffer_size,
1.65 + Mutex* lock, const char* name) : _mutex(lock) {
1.66 + intptr_t size = round_to(buffer_size, 2*BytesPerWord);
1.67 + BufferBlob* blob = BufferBlob::create(name, size);
1.68 + if( blob == NULL ) vm_exit_out_of_memory1(size, "CodeCache: no room for %s", name);
1.69 + _stub_interface = stub_interface;
1.70 + _buffer_size = blob->instructions_size();
1.71 + _buffer_limit = blob->instructions_size();
1.72 + _stub_buffer = blob->instructions_begin();
1.73 + _queue_begin = 0;
1.74 + _queue_end = 0;
1.75 + _number_of_stubs = 0;
1.76 + register_queue(this);
1.77 +}
1.78 +
1.79 +
1.80 +StubQueue::~StubQueue() {
1.81 + // Note: Currently StubQueues are never destroyed so nothing needs to be done here.
1.82 + // If we want to implement the destructor, we need to release the BufferBlob
1.83 + // allocated in the constructor (i.e., we need to keep it around or look it
1.84 + // up via CodeCache::find_blob(...).
1.85 + Unimplemented();
1.86 +}
1.87 +
1.88 +
1.89 +Stub* StubQueue::stub_containing(address pc) const {
1.90 + if (contains(pc)) {
1.91 + for (Stub* s = first(); s != NULL; s = next(s)) {
1.92 + if (stub_contains(s, pc)) return s;
1.93 + }
1.94 + }
1.95 + return NULL;
1.96 +}
1.97 +
1.98 +
1.99 +Stub* StubQueue::request_committed(int code_size) {
1.100 + Stub* s = request(code_size);
1.101 + if (s != NULL) commit(code_size);
1.102 + return s;
1.103 +}
1.104 +
1.105 +
1.106 +Stub* StubQueue::request(int requested_code_size) {
1.107 + assert(requested_code_size > 0, "requested_code_size must be > 0");
1.108 + if (_mutex != NULL) _mutex->lock();
1.109 + Stub* s = current_stub();
1.110 + int requested_size = round_to(stub_code_size_to_size(requested_code_size), CodeEntryAlignment);
1.111 + if (requested_size <= available_space()) {
1.112 + if (is_contiguous()) {
1.113 + // Queue: |...|XXXXXXX|.............|
1.114 + // ^0 ^begin ^end ^size = limit
1.115 + assert(_buffer_limit == _buffer_size, "buffer must be fully usable");
1.116 + if (_queue_end + requested_size <= _buffer_size) {
1.117 + // code fits in at the end => nothing to do
1.118 + stub_initialize(s, requested_size);
1.119 + return s;
1.120 + } else {
1.121 + // stub doesn't fit in at the queue end
1.122 + // => reduce buffer limit & wrap around
1.123 + assert(!is_empty(), "just checkin'");
1.124 + _buffer_limit = _queue_end;
1.125 + _queue_end = 0;
1.126 + }
1.127 + }
1.128 + }
1.129 + if (requested_size <= available_space()) {
1.130 + assert(!is_contiguous(), "just checkin'");
1.131 + assert(_buffer_limit <= _buffer_size, "queue invariant broken");
1.132 + // Queue: |XXX|.......|XXXXXXX|.......|
1.133 + // ^0 ^end ^begin ^limit ^size
1.134 + s = current_stub();
1.135 + stub_initialize(s, requested_size);
1.136 + return s;
1.137 + }
1.138 + // Not enough space left
1.139 + if (_mutex != NULL) _mutex->unlock();
1.140 + return NULL;
1.141 +}
1.142 +
1.143 +
1.144 +void StubQueue::commit(int committed_code_size) {
1.145 + assert(committed_code_size > 0, "committed_code_size must be > 0");
1.146 + int committed_size = round_to(stub_code_size_to_size(committed_code_size), CodeEntryAlignment);
1.147 + Stub* s = current_stub();
1.148 + assert(committed_size <= stub_size(s), "committed size must not exceed requested size");
1.149 + stub_initialize(s, committed_size);
1.150 + _queue_end += committed_size;
1.151 + _number_of_stubs++;
1.152 + if (_mutex != NULL) _mutex->unlock();
1.153 + debug_only(stub_verify(s);)
1.154 +}
1.155 +
1.156 +
1.157 +void StubQueue::remove_first() {
1.158 + if (number_of_stubs() == 0) return;
1.159 + Stub* s = first();
1.160 + debug_only(stub_verify(s);)
1.161 + stub_finalize(s);
1.162 + _queue_begin += stub_size(s);
1.163 + assert(_queue_begin <= _buffer_limit, "sanity check");
1.164 + if (_queue_begin == _queue_end) {
1.165 + // buffer empty
1.166 + // => reset queue indices
1.167 + _queue_begin = 0;
1.168 + _queue_end = 0;
1.169 + _buffer_limit = _buffer_size;
1.170 + } else if (_queue_begin == _buffer_limit) {
1.171 + // buffer limit reached
1.172 + // => reset buffer limit & wrap around
1.173 + _buffer_limit = _buffer_size;
1.174 + _queue_begin = 0;
1.175 + }
1.176 + _number_of_stubs--;
1.177 +}
1.178 +
1.179 +
1.180 +void StubQueue::remove_first(int n) {
1.181 + int i = MIN2(n, number_of_stubs());
1.182 + while (i-- > 0) remove_first();
1.183 +}
1.184 +
1.185 +
1.186 +void StubQueue::remove_all(){
1.187 + debug_only(verify();)
1.188 + remove_first(number_of_stubs());
1.189 + assert(number_of_stubs() == 0, "sanity check");
1.190 +}
1.191 +
1.192 +
1.193 +enum { StubQueueLimit = 10 }; // there are only a few in the world
1.194 +static StubQueue* registered_stub_queues[StubQueueLimit];
1.195 +
1.196 +void StubQueue::register_queue(StubQueue* sq) {
1.197 + for (int i = 0; i < StubQueueLimit; i++) {
1.198 + if (registered_stub_queues[i] == NULL) {
1.199 + registered_stub_queues[i] = sq;
1.200 + return;
1.201 + }
1.202 + }
1.203 + ShouldNotReachHere();
1.204 +}
1.205 +
1.206 +
1.207 +void StubQueue::queues_do(void f(StubQueue* sq)) {
1.208 + for (int i = 0; i < StubQueueLimit; i++) {
1.209 + if (registered_stub_queues[i] != NULL) {
1.210 + f(registered_stub_queues[i]);
1.211 + }
1.212 + }
1.213 +}
1.214 +
1.215 +
1.216 +void StubQueue::stubs_do(void f(Stub* s)) {
1.217 + debug_only(verify();)
1.218 + MutexLockerEx lock(_mutex);
1.219 + for (Stub* s = first(); s != NULL; s = next(s)) f(s);
1.220 +}
1.221 +
1.222 +
1.223 +void StubQueue::verify() {
1.224 + // verify only if initialized
1.225 + if (_stub_buffer == NULL) return;
1.226 + MutexLockerEx lock(_mutex);
1.227 + // verify index boundaries
1.228 + guarantee(0 <= _buffer_size, "buffer size must be positive");
1.229 + guarantee(0 <= _buffer_limit && _buffer_limit <= _buffer_size , "_buffer_limit out of bounds");
1.230 + guarantee(0 <= _queue_begin && _queue_begin < _buffer_limit, "_queue_begin out of bounds");
1.231 + guarantee(0 <= _queue_end && _queue_end <= _buffer_limit, "_queue_end out of bounds");
1.232 + // verify alignment
1.233 + guarantee(_buffer_size % CodeEntryAlignment == 0, "_buffer_size not aligned");
1.234 + guarantee(_buffer_limit % CodeEntryAlignment == 0, "_buffer_limit not aligned");
1.235 + guarantee(_queue_begin % CodeEntryAlignment == 0, "_queue_begin not aligned");
1.236 + guarantee(_queue_end % CodeEntryAlignment == 0, "_queue_end not aligned");
1.237 + // verify buffer limit/size relationship
1.238 + if (is_contiguous()) {
1.239 + guarantee(_buffer_limit == _buffer_size, "_buffer_limit must equal _buffer_size");
1.240 + }
1.241 + // verify contents
1.242 + int n = 0;
1.243 + for (Stub* s = first(); s != NULL; s = next(s)) {
1.244 + stub_verify(s);
1.245 + n++;
1.246 + }
1.247 + guarantee(n == number_of_stubs(), "number of stubs inconsistent");
1.248 + guarantee(_queue_begin != _queue_end || n == 0, "buffer indices must be the same");
1.249 +}
1.250 +
1.251 +
1.252 +void StubQueue::print() {
1.253 + MutexLockerEx lock(_mutex);
1.254 + for (Stub* s = first(); s != NULL; s = next(s)) {
1.255 + stub_print(s);
1.256 + }
1.257 +}
