aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #include "precompiled.hpp"
aoqi@0: #include "code/codeBlob.hpp"
aoqi@0: #include "code/stubs.hpp"
aoqi@0: #include "memory/allocation.inline.hpp"
aoqi@0: #include "oops/oop.inline.hpp"
aoqi@0: #include "runtime/mutexLocker.hpp"
aoqi@0: 
aoqi@0: 
aoqi@0: // Implementation of StubQueue
aoqi@0: //
aoqi@0: // Standard wrap-around queue implementation; the queue dimensions
aoqi@0: // are specified by the _queue_begin & _queue_end indices. The queue
aoqi@0: // can be in two states (transparent to the outside):
aoqi@0: //
aoqi@0: // a) contiguous state: all queue entries in one block (or empty)
aoqi@0: //
aoqi@0: // Queue: |...|XXXXXXX|...............|
aoqi@0: //        ^0  ^begin  ^end            ^size = limit
aoqi@0: //            |_______|
aoqi@0: //            one block
aoqi@0: //
aoqi@0: // b) non-contiguous state: queue entries in two blocks
aoqi@0: //
aoqi@0: // Queue: |XXX|.......|XXXXXXX|.......|
aoqi@0: //        ^0  ^end    ^begin  ^limit  ^size
aoqi@0: //        |___|       |_______|
aoqi@0: //         1st block  2nd block
aoqi@0: //
aoqi@0: // In the non-contiguous state, the wrap-around point is
aoqi@0: // indicated via the _buffer_limit index since the last
aoqi@0: // queue entry may not fill up the queue completely in
aoqi@0: // which case we need to know where the 2nd block's end
aoqi@0: // is to do the proper wrap-around. When removing the
aoqi@0: // last entry of the 2nd block, _buffer_limit is reset
aoqi@0: // to _buffer_size.
aoqi@0: //
aoqi@0: // CAUTION: DO NOT MESS WITH THIS CODE IF YOU CANNOT PROVE
aoqi@0: // ITS CORRECTNESS! THIS CODE IS MORE SUBTLE THAN IT LOOKS!
aoqi@0: 
aoqi@0: 
aoqi@0: StubQueue::StubQueue(StubInterface* stub_interface, int buffer_size,
aoqi@0:                      Mutex* lock, const char* name) : _mutex(lock) {
aoqi@0:   intptr_t size = round_to(buffer_size, 2*BytesPerWord);
aoqi@0:   BufferBlob* blob = BufferBlob::create(name, size);
aoqi@0:   if( blob == NULL) {
aoqi@0:     vm_exit_out_of_memory(size, OOM_MALLOC_ERROR, err_msg("CodeCache: no room for %s", name));
aoqi@0:   }
aoqi@0:   _stub_interface  = stub_interface;
aoqi@0:   _buffer_size     = blob->content_size();
aoqi@0:   _buffer_limit    = blob->content_size();
aoqi@0:   _stub_buffer     = blob->content_begin();
aoqi@0:   _queue_begin     = 0;
aoqi@0:   _queue_end       = 0;
aoqi@0:   _number_of_stubs = 0;
aoqi@0:   register_queue(this);
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: StubQueue::~StubQueue() {
aoqi@0:   // Note: Currently StubQueues are never destroyed so nothing needs to be done here.
aoqi@0:   //       If we want to implement the destructor, we need to release the BufferBlob
aoqi@0:   //       allocated in the constructor (i.e., we need to keep it around or look it
aoqi@0:   //       up via CodeCache::find_blob(...).
aoqi@0:   Unimplemented();
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: Stub* StubQueue::stub_containing(address pc) const {
aoqi@0:   if (contains(pc)) {
aoqi@0:     for (Stub* s = first(); s != NULL; s = next(s)) {
aoqi@0:       if (stub_contains(s, pc)) return s;
aoqi@0:     }
aoqi@0:   }
aoqi@0:   return NULL;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: Stub* StubQueue::request_committed(int code_size) {
aoqi@0:   Stub* s = request(code_size);
aoqi@0:   CodeStrings strings;
aoqi@0:   if (s != NULL) commit(code_size, strings);
aoqi@0:   return s;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: Stub* StubQueue::request(int requested_code_size) {
aoqi@0:   assert(requested_code_size > 0, "requested_code_size must be > 0");
aoqi@0:   if (_mutex != NULL) _mutex->lock();
aoqi@0:   Stub* s = current_stub();
aoqi@0:   int requested_size = round_to(stub_code_size_to_size(requested_code_size), CodeEntryAlignment);
aoqi@0:   if (requested_size <= available_space()) {
aoqi@0:     if (is_contiguous()) {
aoqi@0:       // Queue: |...|XXXXXXX|.............|
aoqi@0:       //        ^0  ^begin  ^end          ^size = limit
aoqi@0:       assert(_buffer_limit == _buffer_size, "buffer must be fully usable");
aoqi@0:       if (_queue_end + requested_size <= _buffer_size) {
aoqi@0:         // code fits in at the end => nothing to do
aoqi@0:         CodeStrings strings;
aoqi@0:         stub_initialize(s, requested_size, strings);
aoqi@0:         return s;
aoqi@0:       } else {
aoqi@0:         // stub doesn't fit in at the queue end
aoqi@0:         // => reduce buffer limit & wrap around
aoqi@0:         assert(!is_empty(), "just checkin'");
aoqi@0:         _buffer_limit = _queue_end;
aoqi@0:         _queue_end = 0;
aoqi@0:       }
aoqi@0:     }
aoqi@0:   }
aoqi@0:   if (requested_size <= available_space()) {
aoqi@0:     assert(!is_contiguous(), "just checkin'");
aoqi@0:     assert(_buffer_limit <= _buffer_size, "queue invariant broken");
aoqi@0:     // Queue: |XXX|.......|XXXXXXX|.......|
aoqi@0:     //        ^0  ^end    ^begin  ^limit  ^size
aoqi@0:     s = current_stub();
aoqi@0:     CodeStrings strings;
aoqi@0:     stub_initialize(s, requested_size, strings);
aoqi@0:     return s;
aoqi@0:   }
aoqi@0:   // Not enough space left
aoqi@0:   if (_mutex != NULL) _mutex->unlock();
aoqi@0:   return NULL;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::commit(int committed_code_size, CodeStrings& strings) {
aoqi@0:   assert(committed_code_size > 0, "committed_code_size must be > 0");
aoqi@0:   int committed_size = round_to(stub_code_size_to_size(committed_code_size), CodeEntryAlignment);
aoqi@0:   Stub* s = current_stub();
aoqi@0:   assert(committed_size <= stub_size(s), "committed size must not exceed requested size");
aoqi@0:   stub_initialize(s, committed_size, strings);
aoqi@0:   _queue_end += committed_size;
aoqi@0:   _number_of_stubs++;
aoqi@0:   if (_mutex != NULL) _mutex->unlock();
aoqi@0:   debug_only(stub_verify(s);)
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::remove_first() {
aoqi@0:   if (number_of_stubs() == 0) return;
aoqi@0:   Stub* s = first();
aoqi@0:   debug_only(stub_verify(s);)
aoqi@0:   stub_finalize(s);
aoqi@0:   _queue_begin += stub_size(s);
aoqi@0:   assert(_queue_begin <= _buffer_limit, "sanity check");
aoqi@0:   if (_queue_begin == _queue_end) {
aoqi@0:     // buffer empty
aoqi@0:     // => reset queue indices
aoqi@0:     _queue_begin  = 0;
aoqi@0:     _queue_end    = 0;
aoqi@0:     _buffer_limit = _buffer_size;
aoqi@0:   } else if (_queue_begin == _buffer_limit) {
aoqi@0:     // buffer limit reached
aoqi@0:     // => reset buffer limit & wrap around
aoqi@0:     _buffer_limit = _buffer_size;
aoqi@0:     _queue_begin = 0;
aoqi@0:   }
aoqi@0:   _number_of_stubs--;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::remove_first(int n) {
aoqi@0:   int i = MIN2(n, number_of_stubs());
aoqi@0:   while (i-- > 0) remove_first();
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::remove_all(){
aoqi@0:   debug_only(verify();)
aoqi@0:   remove_first(number_of_stubs());
aoqi@0:   assert(number_of_stubs() == 0, "sanity check");
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: enum { StubQueueLimit = 10 };  // there are only a few in the world
aoqi@0: static StubQueue* registered_stub_queues[StubQueueLimit];
aoqi@0: 
aoqi@0: void StubQueue::register_queue(StubQueue* sq) {
aoqi@0:   for (int i = 0; i < StubQueueLimit; i++) {
aoqi@0:     if (registered_stub_queues[i] == NULL) {
aoqi@0:       registered_stub_queues[i] = sq;
aoqi@0:       return;
aoqi@0:     }
aoqi@0:   }
aoqi@0:   ShouldNotReachHere();
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::queues_do(void f(StubQueue* sq)) {
aoqi@0:   for (int i = 0; i < StubQueueLimit; i++) {
aoqi@0:     if (registered_stub_queues[i] != NULL) {
aoqi@0:       f(registered_stub_queues[i]);
aoqi@0:     }
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::stubs_do(void f(Stub* s)) {
aoqi@0:   debug_only(verify();)
aoqi@0:   MutexLockerEx lock(_mutex);
aoqi@0:   for (Stub* s = first(); s != NULL; s = next(s)) f(s);
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::verify() {
aoqi@0:   // verify only if initialized
aoqi@0:   if (_stub_buffer == NULL) return;
aoqi@0:   MutexLockerEx lock(_mutex);
aoqi@0:   // verify index boundaries
aoqi@0:   guarantee(0 <= _buffer_size, "buffer size must be positive");
aoqi@0:   guarantee(0 <= _buffer_limit && _buffer_limit <= _buffer_size , "_buffer_limit out of bounds");
aoqi@0:   guarantee(0 <= _queue_begin  && _queue_begin  <  _buffer_limit, "_queue_begin out of bounds");
aoqi@0:   guarantee(0 <= _queue_end    && _queue_end    <= _buffer_limit, "_queue_end   out of bounds");
aoqi@0:   // verify alignment
aoqi@0:   guarantee(_buffer_size  % CodeEntryAlignment == 0, "_buffer_size  not aligned");
aoqi@0:   guarantee(_buffer_limit % CodeEntryAlignment == 0, "_buffer_limit not aligned");
aoqi@0:   guarantee(_queue_begin  % CodeEntryAlignment == 0, "_queue_begin  not aligned");
aoqi@0:   guarantee(_queue_end    % CodeEntryAlignment == 0, "_queue_end    not aligned");
aoqi@0:   // verify buffer limit/size relationship
aoqi@0:   if (is_contiguous()) {
aoqi@0:     guarantee(_buffer_limit == _buffer_size, "_buffer_limit must equal _buffer_size");
aoqi@0:   }
aoqi@0:   // verify contents
aoqi@0:   int n = 0;
aoqi@0:   for (Stub* s = first(); s != NULL; s = next(s)) {
aoqi@0:     stub_verify(s);
aoqi@0:     n++;
aoqi@0:   }
aoqi@0:   guarantee(n == number_of_stubs(), "number of stubs inconsistent");
aoqi@0:   guarantee(_queue_begin != _queue_end || n == 0, "buffer indices must be the same");
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void StubQueue::print() {
aoqi@0:   MutexLockerEx lock(_mutex);
aoqi@0:   for (Stub* s = first(); s != NULL; s = next(s)) {
aoqi@0:     stub_print(s);
aoqi@0:   }
aoqi@0: }