factor/vm/heap.hpp

96 lines
2.2 KiB
C++

namespace factor
{
static const cell free_list_count = 16;
static const cell block_size_increment = 32;
struct heap_free_list {
free_heap_block *small_blocks[free_list_count];
free_heap_block *large_blocks;
};
struct heap {
factor_vm *myvm;
segment *seg;
heap_free_list free;
explicit heap(factor_vm *myvm, cell size);
inline heap_block *next_block(heap_block *block)
{
cell next = ((cell)block + block->size);
if(next == seg->end)
return NULL;
else
return (heap_block *)next;
}
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 new_heap(cell size);
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);
void heap_free(heap_block *block);
void mark_block(heap_block *block);
void unmark_marked();
void heap_usage(cell *used, cell *total_free, cell *max_free);
cell heap_size();
cell compute_heap_forwarding(unordered_map<heap_block *,char *> &forwarding);
void compact_heap(unordered_map<heap_block *,char *> &forwarding);
heap_block *free_allocated(heap_block *prev, heap_block *scan);
/* After code GC, all referenced code blocks have status set to B_MARKED, so any
which are allocated and not marked can be reclaimed. */
template<typename Iterator> void free_unmarked(Iterator &iter)
{
clear_free_list();
heap_block *prev = NULL;
heap_block *scan = first_block();
while(scan)
{
switch(scan->status)
{
case B_ALLOCATED:
prev = free_allocated(prev,scan);
break;
case B_FREE:
if(prev && prev->status == B_FREE)
prev->size += scan->size;
else
prev = scan;
break;
case B_MARKED:
if(prev && prev->status == B_FREE)
add_to_free_list((free_heap_block *)prev);
scan->status = B_ALLOCATED;
prev = scan;
iter(scan);
break;
}
scan = next_block(scan);
}
if(prev && prev->status == B_FREE)
add_to_free_list((free_heap_block *)prev);
}
};
}