diff options
Diffstat (limited to 'py/gc.c')
| -rw-r--r-- | py/gc.c | 22 |
1 files changed, 14 insertions, 8 deletions
@@ -95,6 +95,12 @@ #define BLOCK_FROM_PTR(area, ptr) (((byte *)(ptr) - area->gc_pool_start) / BYTES_PER_BLOCK) #define PTR_FROM_BLOCK(area, block) (((block) * BYTES_PER_BLOCK + (uintptr_t)area->gc_pool_start)) +// After the ATB, there must be a byte filled with AT_FREE so that gc_mark_tree +// cannot erroneously conclude that a block extends past the end of the GC heap +// due to bit patterns in the FTB (or first block, if finalizers are disabled) +// being interpreted as AT_TAIL. +#define ALLOC_TABLE_GAP_BYTE (1) + #if MICROPY_ENABLE_FINALISER // FTB = finaliser table byte // if set, then the corresponding block may have a finaliser @@ -123,16 +129,16 @@ STATIC void gc_setup_area(mp_state_mem_area_t *area, void *start, void *end) { // => T = A * (1 + BLOCKS_PER_ATB / BLOCKS_PER_FTB + BLOCKS_PER_ATB * BYTES_PER_BLOCK) size_t total_byte_len = (byte *)end - (byte *)start; #if MICROPY_ENABLE_FINALISER - area->gc_alloc_table_byte_len = total_byte_len * MP_BITS_PER_BYTE / (MP_BITS_PER_BYTE + MP_BITS_PER_BYTE * BLOCKS_PER_ATB / BLOCKS_PER_FTB + MP_BITS_PER_BYTE * BLOCKS_PER_ATB * BYTES_PER_BLOCK); + area->gc_alloc_table_byte_len = (total_byte_len - ALLOC_TABLE_GAP_BYTE) * MP_BITS_PER_BYTE / (MP_BITS_PER_BYTE + MP_BITS_PER_BYTE * BLOCKS_PER_ATB / BLOCKS_PER_FTB + MP_BITS_PER_BYTE * BLOCKS_PER_ATB * BYTES_PER_BLOCK); #else - area->gc_alloc_table_byte_len = total_byte_len / (1 + MP_BITS_PER_BYTE / 2 * BYTES_PER_BLOCK); + area->gc_alloc_table_byte_len = (total_byte_len - ALLOC_TABLE_GAP_BYTE) / (1 + MP_BITS_PER_BYTE / 2 * BYTES_PER_BLOCK); #endif area->gc_alloc_table_start = (byte *)start; #if MICROPY_ENABLE_FINALISER size_t gc_finaliser_table_byte_len = (area->gc_alloc_table_byte_len * BLOCKS_PER_ATB + BLOCKS_PER_FTB - 1) / BLOCKS_PER_FTB; - area->gc_finaliser_table_start = area->gc_alloc_table_start + area->gc_alloc_table_byte_len; + area->gc_finaliser_table_start = area->gc_alloc_table_start + area->gc_alloc_table_byte_len + ALLOC_TABLE_GAP_BYTE; #endif size_t gc_pool_block_len = area->gc_alloc_table_byte_len * BLOCKS_PER_ATB; @@ -143,12 +149,12 @@ STATIC void gc_setup_area(mp_state_mem_area_t *area, void *start, void *end) { assert(area->gc_pool_start >= area->gc_finaliser_table_start + gc_finaliser_table_byte_len); #endif - // clear ATBs - memset(area->gc_alloc_table_start, 0, area->gc_alloc_table_byte_len); - #if MICROPY_ENABLE_FINALISER - // clear FTBs - memset(area->gc_finaliser_table_start, 0, gc_finaliser_table_byte_len); + // clear ATBs and FTBs + memset(area->gc_alloc_table_start, 0, gc_finaliser_table_byte_len + area->gc_alloc_table_byte_len + ALLOC_TABLE_GAP_BYTE); + #else + // clear ATBs + memset(area->gc_alloc_table_start, 0, area->gc_alloc_table_byte_len + ALLOC_TABLE_GAP_BYTE); #endif area->gc_last_free_atb_index = 0; |