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gc: reserve first block; lexer: free vstr.

This commit is contained in:
Damien 2013-10-22 21:12:29 +01:00
parent fd8b6bcf55
commit bb5316b905
2 changed files with 32 additions and 26 deletions
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57
py/gc.c
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@ -20,7 +20,6 @@ typedef unsigned char byte;
#define STACK_SIZE (64) // tunable; minimum is 1
static byte *gc_alloc_table_start;
static byte *gc_alloc_table_end;
static machine_uint_t gc_alloc_table_byte_len;
static machine_uint_t *gc_pool_start;
static machine_uint_t *gc_pool_end;
@ -29,31 +28,6 @@ static int gc_stack_overflow;
static machine_uint_t gc_stack[STACK_SIZE];
static machine_uint_t *gc_sp;
// TODO waste less memory; currently requires that all entries in alloc_table have a corresponding block in pool
void gc_init(void *start, void *end) {
// align end pointer on block boundary
end = (void*)((machine_uint_t)end & (~(BYTES_PER_BLOCK - 1)));
// calculate parameters for GC
machine_uint_t total_word_len = (machine_uint_t*)end - (machine_uint_t*)start;
gc_alloc_table_byte_len = total_word_len * BYTES_PER_WORD / (1 + BITS_PER_BYTE / 2 * BYTES_PER_BLOCK);
gc_alloc_table_start = (byte*)start;
gc_alloc_table_end = gc_alloc_table_start + gc_alloc_table_byte_len;
machine_uint_t gc_pool_block_len = gc_alloc_table_byte_len * BITS_PER_BYTE / 2;
machine_uint_t gc_pool_word_len = gc_pool_block_len * WORDS_PER_BLOCK;
gc_pool_start = (machine_uint_t*)end - gc_pool_word_len;
gc_pool_end = end;
// clear ATBs
memset(gc_alloc_table_start, 0, gc_alloc_table_byte_len);
/*
printf("GC layout:\n");
printf(" alloc table at %p, length %u bytes\n", gc_alloc_table_start, gc_alloc_table_byte_len);
printf(" pool at %p, length %u blocks = %u words = %u bytes\n", gc_pool_start, gc_pool_block_len, gc_pool_word_len, gc_pool_word_len * BYTES_PER_WORD);
*/
}
// ATB = allocation table byte
// 0b00 = FREE -- free block
// 0b01 = HEAD -- head of a chain of blocks
@ -88,6 +62,37 @@ void gc_init(void *start, void *end) {
#define PTR_FROM_BLOCK(block) (((block) * BYTES_PER_BLOCK + (machine_uint_t)gc_pool_start))
#define ATB_FROM_BLOCK(bl) ((bl) / BLOCKS_PER_ATB)
// TODO waste less memory; currently requires that all entries in alloc_table have a corresponding block in pool
void gc_init(void *start, void *end) {
// align end pointer on block boundary
end = (void*)((machine_uint_t)end & (~(BYTES_PER_BLOCK - 1)));
// calculate parameters for GC
machine_uint_t total_word_len = (machine_uint_t*)end - (machine_uint_t*)start;
gc_alloc_table_byte_len = total_word_len * BYTES_PER_WORD / (1 + BITS_PER_BYTE / 2 * BYTES_PER_BLOCK);
gc_alloc_table_start = (byte*)start;
machine_uint_t gc_pool_block_len = gc_alloc_table_byte_len * BITS_PER_BYTE / 2;
machine_uint_t gc_pool_word_len = gc_pool_block_len * WORDS_PER_BLOCK;
gc_pool_start = (machine_uint_t*)end - gc_pool_word_len;
gc_pool_end = end;
// clear ATBs
memset(gc_alloc_table_start, 0, gc_alloc_table_byte_len);
// allocate first block because gc_pool_start points there and it will never
// be freed, so allocating 1 block with null pointers will minimise memory loss
ATB_FREE_TO_HEAD(0);
for (int i = 0; i < WORDS_PER_BLOCK; i++) {
gc_pool_start[i] = 0;
}
/*
printf("GC layout:\n");
printf(" alloc table at %p, length %u bytes\n", gc_alloc_table_start, gc_alloc_table_byte_len);
printf(" pool at %p, length %u blocks = %u words = %u bytes\n", gc_pool_start, gc_pool_block_len, gc_pool_word_len, gc_pool_word_len * BYTES_PER_WORD);
*/
}
#define VERIFY_PTR(ptr) ( \
(ptr & (BYTES_PER_BLOCK - 1)) == 0 /* must be aligned on a block */ \
&& ptr >= (machine_uint_t)gc_pool_start /* must be above start of pool */ \

1
py/lexer.c
View File

@ -635,6 +635,7 @@ void py_lexer_free(py_lexer_t *lex) {
if (lex->stream_close) {
lex->stream_close(lex->stream_data);
}
vstr_clear(&lex->vstr);
m_free(lex);
}
}