--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/code/stubs.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,254 @@
+/*
+ * Copyright 1997-2005 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.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_stubs.cpp.incl"
+
+
+// Implementation of StubQueue
+//
+// Standard wrap-around queue implementation; the queue dimensions
+// are specified by the _queue_begin & _queue_end indices. The queue
+// can be in two states (transparent to the outside):
+//
+// a) contiguous state: all queue entries in one block (or empty)
+//
+// Queue: |...|XXXXXXX|...............|
+// ^0 ^begin ^end ^size = limit
+// |_______|
+// one block
+//
+// b) non-contiguous state: queue entries in two blocks
+//
+// Queue: |XXX|.......|XXXXXXX|.......|
+// ^0 ^end ^begin ^limit ^size
+// |___| |_______|
+// 1st block 2nd block
+//
+// In the non-contiguous state, the wrap-around point is
+// indicated via the _buffer_limit index since the last
+// queue entry may not fill up the queue completely in
+// which case we need to know where the 2nd block's end
+// is to do the proper wrap-around. When removing the
+// last entry of the 2nd block, _buffer_limit is reset
+// to _buffer_size.
+//
+// CAUTION: DO NOT MESS WITH THIS CODE IF YOU CANNOT PROVE
+// ITS CORRECTNESS! THIS CODE IS MORE SUBTLE THAN IT LOOKS!
+
+
+StubQueue::StubQueue(StubInterface* stub_interface, int buffer_size,
+ Mutex* lock, const char* name) : _mutex(lock) {
+ intptr_t size = round_to(buffer_size, 2*BytesPerWord);
+ BufferBlob* blob = BufferBlob::create(name, size);
+ if( blob == NULL ) vm_exit_out_of_memory1(size, "CodeCache: no room for %s", name);
+ _stub_interface = stub_interface;
+ _buffer_size = blob->instructions_size();
+ _buffer_limit = blob->instructions_size();
+ _stub_buffer = blob->instructions_begin();
+ _queue_begin = 0;
+ _queue_end = 0;
+ _number_of_stubs = 0;
+ register_queue(this);
+}
+
+
+StubQueue::~StubQueue() {
+ // Note: Currently StubQueues are never destroyed so nothing needs to be done here.
+ // If we want to implement the destructor, we need to release the BufferBlob
+ // allocated in the constructor (i.e., we need to keep it around or look it
+ // up via CodeCache::find_blob(...).
+ Unimplemented();
+}
+
+
+Stub* StubQueue::stub_containing(address pc) const {
+ if (contains(pc)) {
+ for (Stub* s = first(); s != NULL; s = next(s)) {
+ if (stub_contains(s, pc)) return s;
+ }
+ }
+ return NULL;
+}
+
+
+Stub* StubQueue::request_committed(int code_size) {
+ Stub* s = request(code_size);
+ if (s != NULL) commit(code_size);
+ return s;
+}
+
+
+Stub* StubQueue::request(int requested_code_size) {
+ assert(requested_code_size > 0, "requested_code_size must be > 0");
+ if (_mutex != NULL) _mutex->lock();
+ Stub* s = current_stub();
+ int requested_size = round_to(stub_code_size_to_size(requested_code_size), CodeEntryAlignment);
+ if (requested_size <= available_space()) {
+ if (is_contiguous()) {
+ // Queue: |...|XXXXXXX|.............|
+ // ^0 ^begin ^end ^size = limit
+ assert(_buffer_limit == _buffer_size, "buffer must be fully usable");
+ if (_queue_end + requested_size <= _buffer_size) {
+ // code fits in at the end => nothing to do
+ stub_initialize(s, requested_size);
+ return s;
+ } else {
+ // stub doesn't fit in at the queue end
+ // => reduce buffer limit & wrap around
+ assert(!is_empty(), "just checkin'");
+ _buffer_limit = _queue_end;
+ _queue_end = 0;
+ }
+ }
+ }
+ if (requested_size <= available_space()) {
+ assert(!is_contiguous(), "just checkin'");
+ assert(_buffer_limit <= _buffer_size, "queue invariant broken");
+ // Queue: |XXX|.......|XXXXXXX|.......|
+ // ^0 ^end ^begin ^limit ^size
+ s = current_stub();
+ stub_initialize(s, requested_size);
+ return s;
+ }
+ // Not enough space left
+ if (_mutex != NULL) _mutex->unlock();
+ return NULL;
+}
+
+
+void StubQueue::commit(int committed_code_size) {
+ assert(committed_code_size > 0, "committed_code_size must be > 0");
+ int committed_size = round_to(stub_code_size_to_size(committed_code_size), CodeEntryAlignment);
+ Stub* s = current_stub();
+ assert(committed_size <= stub_size(s), "committed size must not exceed requested size");
+ stub_initialize(s, committed_size);
+ _queue_end += committed_size;
+ _number_of_stubs++;
+ if (_mutex != NULL) _mutex->unlock();
+ debug_only(stub_verify(s);)
+}
+
+
+void StubQueue::remove_first() {
+ if (number_of_stubs() == 0) return;
+ Stub* s = first();
+ debug_only(stub_verify(s);)
+ stub_finalize(s);
+ _queue_begin += stub_size(s);
+ assert(_queue_begin <= _buffer_limit, "sanity check");
+ if (_queue_begin == _queue_end) {
+ // buffer empty
+ // => reset queue indices
+ _queue_begin = 0;
+ _queue_end = 0;
+ _buffer_limit = _buffer_size;
+ } else if (_queue_begin == _buffer_limit) {
+ // buffer limit reached
+ // => reset buffer limit & wrap around
+ _buffer_limit = _buffer_size;
+ _queue_begin = 0;
+ }
+ _number_of_stubs--;
+}
+
+
+void StubQueue::remove_first(int n) {
+ int i = MIN2(n, number_of_stubs());
+ while (i-- > 0) remove_first();
+}
+
+
+void StubQueue::remove_all(){
+ debug_only(verify();)
+ remove_first(number_of_stubs());
+ assert(number_of_stubs() == 0, "sanity check");
+}
+
+
+enum { StubQueueLimit = 10 }; // there are only a few in the world
+static StubQueue* registered_stub_queues[StubQueueLimit];
+
+void StubQueue::register_queue(StubQueue* sq) {
+ for (int i = 0; i < StubQueueLimit; i++) {
+ if (registered_stub_queues[i] == NULL) {
+ registered_stub_queues[i] = sq;
+ return;
+ }
+ }
+ ShouldNotReachHere();
+}
+
+
+void StubQueue::queues_do(void f(StubQueue* sq)) {
+ for (int i = 0; i < StubQueueLimit; i++) {
+ if (registered_stub_queues[i] != NULL) {
+ f(registered_stub_queues[i]);
+ }
+ }
+}
+
+
+void StubQueue::stubs_do(void f(Stub* s)) {
+ debug_only(verify();)
+ MutexLockerEx lock(_mutex);
+ for (Stub* s = first(); s != NULL; s = next(s)) f(s);
+}
+
+
+void StubQueue::verify() {
+ // verify only if initialized
+ if (_stub_buffer == NULL) return;
+ MutexLockerEx lock(_mutex);
+ // verify index boundaries
+ guarantee(0 <= _buffer_size, "buffer size must be positive");
+ guarantee(0 <= _buffer_limit && _buffer_limit <= _buffer_size , "_buffer_limit out of bounds");
+ guarantee(0 <= _queue_begin && _queue_begin < _buffer_limit, "_queue_begin out of bounds");
+ guarantee(0 <= _queue_end && _queue_end <= _buffer_limit, "_queue_end out of bounds");
+ // verify alignment
+ guarantee(_buffer_size % CodeEntryAlignment == 0, "_buffer_size not aligned");
+ guarantee(_buffer_limit % CodeEntryAlignment == 0, "_buffer_limit not aligned");
+ guarantee(_queue_begin % CodeEntryAlignment == 0, "_queue_begin not aligned");
+ guarantee(_queue_end % CodeEntryAlignment == 0, "_queue_end not aligned");
+ // verify buffer limit/size relationship
+ if (is_contiguous()) {
+ guarantee(_buffer_limit == _buffer_size, "_buffer_limit must equal _buffer_size");
+ }
+ // verify contents
+ int n = 0;
+ for (Stub* s = first(); s != NULL; s = next(s)) {
+ stub_verify(s);
+ n++;
+ }
+ guarantee(n == number_of_stubs(), "number of stubs inconsistent");
+ guarantee(_queue_begin != _queue_end || n == 0, "buffer indices must be the same");
+}
+
+
+void StubQueue::print() {
+ MutexLockerEx lock(_mutex);
+ for (Stub* s = first(); s != NULL; s = next(s)) {
+ stub_print(s);
+ }
+}