factor/vm/free_list_allocator.hpp

216 lines
5.9 KiB
C++

namespace factor {
struct allocator_room {
cell size;
cell occupied_space;
cell total_free;
cell contiguous_free;
cell free_block_count;
};
template <typename Block> struct free_list_allocator {
cell size;
cell start;
cell end;
free_list free_blocks;
mark_bits state;
free_list_allocator(cell size, cell start);
void initial_free_list(cell occupied);
bool contains_p(Block* block);
Block* next_allocated_block_after(Block* block);
bool can_allot_p(cell size);
Block* allot(cell size);
void free(Block* block);
cell occupied_space();
cell free_space();
cell largest_free_block();
cell free_block_count();
void sweep();
template <typename Iterator> void sweep(Iterator& iter);
template <typename Iterator, typename Fixup>
void compact(Iterator& iter, Fixup fixup, const Block** finger);
template <typename Iterator, typename Fixup>
void iterate(Iterator& iter, Fixup fixup);
template <typename Iterator> void iterate(Iterator& iter);
allocator_room as_allocator_room();
};
template <typename Block>
free_list_allocator<Block>::free_list_allocator(cell size, cell start)
: size(size),
start(start),
end(start + size),
state(mark_bits(size, start)) {
initial_free_list(0);
}
template <typename Block>
void free_list_allocator<Block>::initial_free_list(cell occupied) {
free_blocks.initial_free_list(start, end, occupied);
}
template <typename Block>
bool free_list_allocator<Block>::contains_p(Block* block) {
return ((cell)block - start) < size;
}
template <typename Block>
Block* free_list_allocator<Block>::next_allocated_block_after(Block* block) {
while ((cell)block != this->end && block->free_p()) {
free_heap_block* free_block = (free_heap_block*)block;
block = (Block*)((cell)free_block + free_block->size());
}
if ((cell)block == this->end)
return NULL;
else
return block;
}
template <typename Block>
bool free_list_allocator<Block>::can_allot_p(cell size) {
return free_blocks.can_allot_p(size);
}
template <typename Block> Block* free_list_allocator<Block>::allot(cell size) {
size = align(size, data_alignment);
free_heap_block* block = free_blocks.find_free_block(size);
if (block) {
block = free_blocks.split_free_block(block, size);
return (Block*)block;
} else
return NULL;
}
template <typename Block> void free_list_allocator<Block>::free(Block* block) {
free_heap_block* free_block = (free_heap_block*)block;
free_block->make_free(block->size());
free_blocks.add_to_free_list(free_block);
}
template <typename Block> cell free_list_allocator<Block>::free_space() {
return free_blocks.free_space;
}
template <typename Block> cell free_list_allocator<Block>::occupied_space() {
return size - free_blocks.free_space;
}
template <typename Block>
cell free_list_allocator<Block>::largest_free_block() {
return free_blocks.largest_free_block();
}
template <typename Block> cell free_list_allocator<Block>::free_block_count() {
return free_blocks.free_block_count;
}
template <typename Block>
template <typename Iterator>
void free_list_allocator<Block>::sweep(Iterator& iter) {
free_blocks.clear_free_list();
cell start = this->start;
cell end = this->end;
while (start != end) {
/* find next unmarked block */
start = state.next_unmarked_block_after(start);
if (start != end) {
/* find size */
cell size = state.unmarked_block_size(start);
FACTOR_ASSERT(size > 0);
free_heap_block* free_block = (free_heap_block*)start;
free_block->make_free(size);
free_blocks.add_to_free_list(free_block);
iter((Block*)start, size);
start = start + size;
}
}
}
template <typename Block> struct null_sweep_iterator {
void operator()(Block* free_block, cell size) {}
};
template <typename Block> void free_list_allocator<Block>::sweep() {
null_sweep_iterator<Block> none;
sweep(none);
}
template <typename Block, typename Iterator> struct heap_compactor {
mark_bits* state;
char* address;
Iterator& iter;
const Block** finger;
heap_compactor(mark_bits* state, Block* address,
Iterator& iter, const Block** finger)
: state(state), address((char*)address), iter(iter), finger(finger) {}
void operator()(Block* block, cell size) {
if (this->state->marked_p((cell)block)) {
*finger = (Block*)((char*)block + size);
memmove((Block*)address, block, size);
iter(block, (Block*)address, size);
address += size;
}
}
};
/* The forwarding map must be computed first by calling
state.compute_forwarding(). */
template <typename Block>
template <typename Iterator, typename Fixup>
void free_list_allocator<Block>::compact(Iterator& iter, Fixup fixup,
const Block** finger) {
heap_compactor<Block, Iterator> compactor(&state, (Block*)start, iter, finger);
iterate(compactor, fixup);
/* Now update the free list; there will be a single free block at
the end */
free_blocks.initial_free_list(start, end, (cell)compactor.address - start);
}
/* During compaction we have to be careful and measure object sizes
differently */
template <typename Block>
template <typename Iterator, typename Fixup>
void free_list_allocator<Block>::iterate(Iterator& iter, Fixup fixup) {
Block* scan = (Block*)this->start;
Block* end = (Block*)this->end;
while (scan != end) {
cell size = fixup.size(scan);
Block* next = (Block*)((cell)scan + size);
if (!scan->free_p())
iter(scan, size);
scan = next;
}
}
template <typename Block>
template <typename Iterator>
void free_list_allocator<Block>::iterate(Iterator& iter) {
iterate(iter, no_fixup());
}
template <typename Block>
allocator_room free_list_allocator<Block>::as_allocator_room() {
allocator_room room;
room.size = size;
room.occupied_space = occupied_space();
room.total_free = free_space();
room.contiguous_free = largest_free_block();
room.free_block_count = free_block_count();
return room;
}
}