factor/vm/heap.hpp

112 lines
2.8 KiB
C++

namespace factor
{
static const cell free_list_count = 32;
static const cell block_size_increment = 16;
struct heap_free_list {
free_heap_block *small_blocks[free_list_count];
free_heap_block *large_blocks;
};
struct heap {
bool secure_gc;
segment *seg;
heap_free_list free;
mark_bits<heap_block,block_size_increment> *state;
explicit heap(bool secure_gc_, cell size, bool executable_p);
~heap();
inline heap_block *first_block()
{
return (heap_block *)seg->start;
}
inline heap_block *last_block()
{
return (heap_block *)seg->end;
}
void clear_free_list();
void add_to_free_list(free_heap_block *block);
void build_free_list(cell size);
void assert_free_block(free_heap_block *block);
free_heap_block *find_free_block(cell size);
free_heap_block *split_free_block(free_heap_block *block, cell size);
heap_block *heap_allot(cell size, cell type);
void heap_free(heap_block *block);
void mark_block(heap_block *block);
void heap_usage(cell *used, cell *total_free, cell *max_free);
cell heap_size();
void compact_heap();
heap_block *free_allocated(heap_block *prev, heap_block *scan);
template<typename Iterator> void sweep_heap(Iterator &iter);
template<typename Iterator> void compact_heap(Iterator &iter);
template<typename Iterator> void iterate_heap(Iterator &iter)
{
heap_block *scan = first_block();
heap_block *end = last_block();
while(scan != end)
{
heap_block *next = scan->next();
if(scan->type() != FREE_BLOCK_TYPE) iter(scan,scan->size());
scan = next;
}
}
};
/* After code GC, all live code blocks are marked, so any
which are not marked can be reclaimed. */
template<typename Iterator> void heap::sweep_heap(Iterator &iter)
{
this->clear_free_list();
heap_block *prev = NULL;
heap_block *scan = this->first_block();
heap_block *end = this->last_block();
while(scan != end)
{
if(scan->type() == FREE_BLOCK_TYPE)
{
if(prev && prev->type() == FREE_BLOCK_TYPE)
prev->set_size(prev->size() + scan->size());
else
prev = scan;
}
else if(this->state->is_marked_p(scan))
{
if(prev && prev->type() == FREE_BLOCK_TYPE)
this->add_to_free_list((free_heap_block *)prev);
prev = scan;
iter(scan,scan->size());
}
else
prev = this->free_allocated(prev,scan);
scan = scan->next();
}
if(prev && prev->type() == FREE_BLOCK_TYPE)
this->add_to_free_list((free_heap_block *)prev);
}
/* The forwarding map must be computed first by calling
state->compute_forwarding(). */
template<typename Iterator> void heap::compact_heap(Iterator &iter)
{
heap_compacter<heap_block,block_size_increment,Iterator> compacter(state,first_block(),iter);
this->iterate_heap(compacter);
/* Now update the free list; there will be a single free block at
the end */
this->build_free_list((cell)compacter.address - this->seg->start);
}
}