< prev index next >
src/share/vm/gc/g1/ptrQueue.hpp
Print this page
rev 10256 : [mq]: bufnode_cleanup
rev 10257 : [mq]: flexible_array
@@ -1,7 +1,7 @@
/*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. 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.
@@ -31,13 +31,10 @@
// There are various techniques that require threads to be able to log
// addresses. For example, a generational write barrier might log
// the addresses of modified old-generation objects. This type supports
// this operation.
-// The definition of placement operator new(size_t, void*) in the <new>.
-#include <new>
-
class PtrQueueSet;
class PtrQueue VALUE_OBJ_CLASS_SPEC {
friend class VMStructs;
// Noncopyable - not defined.
@@ -163,49 +160,49 @@
static ByteSize byte_width_of_active() { return in_ByteSize(sizeof(bool)); }
};
+// A BufferNode has some header fields, followed by storage for the
+// buffer. In C99 terms, it has a flexible array member for the
+// buffer. However, C++ doesn't support flexible array members, so
+// we're forced to fake it.
class BufferNode {
size_t _index;
BufferNode* _next;
-public:
+ void* _buffer[1]; // Pseudo flexible array member.
+
BufferNode() : _index(0), _next(NULL) { }
+ ~BufferNode() { }
+
+ static size_t buffer_offset() {
+ return offset_of(BufferNode, _buffer);
+ }
+
+public:
BufferNode* next() const { return _next; }
void set_next(BufferNode* n) { _next = n; }
size_t index() const { return _index; }
void set_index(size_t i) { _index = i; }
- // Align the size of the structure to the size of the pointer
- static size_t aligned_size() {
- static const size_t alignment = round_to(sizeof(BufferNode), sizeof(void*));
- return alignment;
- }
+ // Allocate a new BufferNode with the "buffer" having size bytes.
+ static BufferNode* allocate(size_t byte_size);
- // BufferNode is allocated before the buffer.
- // The chunk of memory that holds both of them is a block.
+ // Free a BufferNode.
+ static void deallocate(BufferNode* node);
- // Produce a new BufferNode given a buffer.
- static BufferNode* new_from_buffer(void** buf) {
- return new (make_block_from_buffer(buf)) BufferNode;
+ // Return the BufferNode containing the buffer.
+ static BufferNode* make_node_from_buffer(void** buffer) {
+ return reinterpret_cast<BufferNode*>(
+ reinterpret_cast<char*>(buffer) - buffer_offset());
}
- // The following are the required conversion routines:
- static BufferNode* make_node_from_buffer(void** buf) {
- return (BufferNode*)make_block_from_buffer(buf);
- }
+ // Return the buffer for node.
static void** make_buffer_from_node(BufferNode *node) {
- return make_buffer_from_block(node);
- }
- static void* make_block_from_node(BufferNode *node) {
- return (void*)node;
- }
- static void** make_buffer_from_block(void* p) {
- return (void**)((char*)p + aligned_size());
- }
- static void* make_block_from_buffer(void** p) {
- return (void*)((char*)p - aligned_size());
+ // &_buffer[0] might lead to index out of bounds warnings.
+ return reinterpret_cast<void**>(
+ reinterpret_cast<char*>(node) + buffer_offset());
}
};
// A PtrQueueSet represents resources common to a set of pointer queues.
// In particular, the individual queues allocate buffers from this shared
< prev index next >