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faster and simpler implementation of regexp backtracking

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This commit is contained in:
Fabrice Bellard
2025-11-22 10:44:19 +01:00
parent fcbf5ea2a6
commit 7ab23413b8
2 changed files with 320 additions and 339 deletions
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14
libregexp-opcode.h
View File

@@ -39,12 +39,13 @@ DEF(goto, 5)
DEF(split_goto_first, 5) DEF(split_goto_first, 5)
DEF(split_next_first, 5) DEF(split_next_first, 5)
DEF(match, 1) DEF(match, 1)
DEF(lookahead_match, 1)
DEF(negative_lookahead_match, 1) /* must come after */
DEF(save_start, 2) /* save start position */ DEF(save_start, 2) /* save start position */
DEF(save_end, 2) /* save end position, must come after saved_start */ DEF(save_end, 2) /* save end position, must come after saved_start */
DEF(save_reset, 3) /* reset save positions */ DEF(save_reset, 3) /* reset save positions */
DEF(loop, 5) /* decrement the top the stack and goto if != 0 */ DEF(loop, 6) /* decrement the top the stack and goto if != 0 */
DEF(push_i32, 5) /* push integer on the stack */ DEF(push_i32, 6) /* push integer on the stack */
DEF(drop, 1)
DEF(word_boundary, 1) DEF(word_boundary, 1)
DEF(word_boundary_i, 1) DEF(word_boundary_i, 1)
DEF(not_word_boundary, 1) DEF(not_word_boundary, 1)
@@ -58,10 +59,9 @@ DEF(range_i, 3) /* variable length */
DEF(range32, 3) /* variable length */ DEF(range32, 3) /* variable length */
DEF(range32_i, 3) /* variable length */ DEF(range32_i, 3) /* variable length */
DEF(lookahead, 5) DEF(lookahead, 5)
DEF(negative_lookahead, 5) DEF(negative_lookahead, 5) /* must come after */
DEF(push_char_pos, 1) /* push the character position on the stack */ DEF(push_char_pos, 2) /* push the character position on the stack */
DEF(check_advance, 1) /* pop one stack element and check that it is different from the character position */ DEF(check_advance, 2) /* pop one stack element and check that it is different from the character position */
DEF(prev, 1) /* go to the previous char */ DEF(prev, 1) /* go to the previous char */
DEF(simple_greedy_quant, 17)
#endif /* DEF */ #endif /* DEF */

643
libregexp.c
View File

@@ -44,6 +44,8 @@
#if defined(TEST) #if defined(TEST)
#define DUMP_REOP #define DUMP_REOP
#endif #endif
//#define DUMP_REOP
//#define DUMP_EXEC
typedef enum { typedef enum {
#define DEF(id, size) REOP_ ## id, #define DEF(id, size) REOP_ ## id,
@@ -459,14 +461,14 @@ static __maybe_unused void lre_dump_bytecode(const uint8_t *buf,
int buf_len) int buf_len)
{ {
int pos, len, opcode, bc_len, re_flags, i; int pos, len, opcode, bc_len, re_flags, i;
uint32_t val; uint32_t val, val2;
assert(buf_len >= RE_HEADER_LEN); assert(buf_len >= RE_HEADER_LEN);
re_flags = lre_get_flags(buf); re_flags = lre_get_flags(buf);
bc_len = get_u32(buf + RE_HEADER_BYTECODE_LEN); bc_len = get_u32(buf + RE_HEADER_BYTECODE_LEN);
assert(bc_len + RE_HEADER_LEN <= buf_len); assert(bc_len + RE_HEADER_LEN <= buf_len);
printf("flags: 0x%x capture_count=%d stack_size=%d\n", printf("flags: 0x%x capture_count=%d aux_stack_size=%d\n",
re_flags, buf[RE_HEADER_CAPTURE_COUNT], buf[RE_HEADER_STACK_SIZE]); re_flags, buf[RE_HEADER_CAPTURE_COUNT], buf[RE_HEADER_STACK_SIZE]);
if (re_flags & LRE_FLAG_NAMED_GROUPS) { if (re_flags & LRE_FLAG_NAMED_GROUPS) {
const char *p; const char *p;
@@ -518,19 +520,17 @@ static __maybe_unused void lre_dump_bytecode(const uint8_t *buf,
case REOP_goto: case REOP_goto:
case REOP_split_goto_first: case REOP_split_goto_first:
case REOP_split_next_first: case REOP_split_next_first:
case REOP_loop:
case REOP_lookahead: case REOP_lookahead:
case REOP_negative_lookahead: case REOP_negative_lookahead:
val = get_u32(buf + pos + 1); val = get_u32(buf + pos + 1);
val += (pos + 5); val += (pos + 5);
printf(" %u", val); printf(" %u", val);
break; break;
case REOP_simple_greedy_quant: case REOP_loop:
printf(" %u %u %u %u", val2 = buf[pos + 1];
get_u32(buf + pos + 1) + (pos + 17), val = get_u32(buf + pos + 2);
get_u32(buf + pos + 1 + 4), val += (pos + 6);
get_u32(buf + pos + 1 + 8), printf(" %u, %u", val2, val);
get_u32(buf + pos + 1 + 12));
break; break;
case REOP_save_start: case REOP_save_start:
case REOP_save_end: case REOP_save_end:
@@ -544,8 +544,14 @@ static __maybe_unused void lre_dump_bytecode(const uint8_t *buf,
printf(" %u %u", buf[pos + 1], buf[pos + 2]); printf(" %u %u", buf[pos + 1], buf[pos + 2]);
break; break;
case REOP_push_i32: case REOP_push_i32:
val = get_u32(buf + pos + 1); val = buf[pos + 1];
printf(" %d", val); val2 = get_u32(buf + pos + 2);
printf(" %u, %d", val, val2);
break;
case REOP_push_char_pos:
case REOP_check_advance:
val = buf[pos + 1];
printf(" %u", val);
break; break;
case REOP_range: case REOP_range:
case REOP_range_i: case REOP_range_i:
@@ -604,6 +610,16 @@ static int re_emit_goto(REParseState *s, int op, uint32_t val)
return pos; return pos;
} }
static int re_emit_goto_u8(REParseState *s, int op, uint32_t arg, uint32_t val)
{
int pos;
dbuf_putc(&s->byte_code, op);
dbuf_putc(&s->byte_code, arg);
pos = s->byte_code.size;
dbuf_put_u32(&s->byte_code, val - (pos + 4));
return pos;
}
static void re_emit_op_u8(REParseState *s, int op, uint32_t val) static void re_emit_op_u8(REParseState *s, int op, uint32_t val)
{ {
dbuf_putc(&s->byte_code, op); dbuf_putc(&s->byte_code, op);
@@ -1532,7 +1548,6 @@ static BOOL re_need_check_advance(const uint8_t *bc_buf, int bc_buf_len)
case REOP_line_end_m: case REOP_line_end_m:
case REOP_push_i32: case REOP_push_i32:
case REOP_push_char_pos: case REOP_push_char_pos:
case REOP_drop:
case REOP_word_boundary: case REOP_word_boundary:
case REOP_word_boundary_i: case REOP_word_boundary_i:
case REOP_not_word_boundary: case REOP_not_word_boundary:
@@ -1557,55 +1572,6 @@ static BOOL re_need_check_advance(const uint8_t *bc_buf, int bc_buf_len)
return ret; return ret;
} }
/* return -1 if a simple quantifier cannot be used. Otherwise return
the number of characters in the atom. */
static int re_is_simple_quantifier(const uint8_t *bc_buf, int bc_buf_len)
{
int pos, opcode, len, count;
uint32_t val;
count = 0;
pos = 0;
while (pos < bc_buf_len) {
opcode = bc_buf[pos];
len = reopcode_info[opcode].size;
switch(opcode) {
case REOP_range:
case REOP_range_i:
val = get_u16(bc_buf + pos + 1);
len += val * 4;
goto simple_char;
case REOP_range32:
case REOP_range32_i:
val = get_u16(bc_buf + pos + 1);
len += val * 8;
goto simple_char;
case REOP_char:
case REOP_char_i:
case REOP_char32:
case REOP_char32_i:
case REOP_dot:
case REOP_any:
simple_char:
count++;
break;
case REOP_line_start:
case REOP_line_start_m:
case REOP_line_end:
case REOP_line_end_m:
case REOP_word_boundary:
case REOP_word_boundary_i:
case REOP_not_word_boundary:
case REOP_not_word_boundary_i:
break;
default:
return -1;
}
pos += len;
}
return count;
}
/* '*pp' is the first char after '<' */ /* '*pp' is the first char after '<' */
static int re_parse_group_name(char *buf, int buf_size, const uint8_t **pp) static int re_parse_group_name(char *buf, int buf_size, const uint8_t **pp)
{ {
@@ -1921,7 +1887,7 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
p = s->buf_ptr; p = s->buf_ptr;
if (re_parse_expect(s, &p, ')')) if (re_parse_expect(s, &p, ')'))
return -1; return -1;
re_emit_op(s, REOP_match); re_emit_op(s, REOP_lookahead_match + is_neg);
/* jump after the 'match' after the lookahead is successful */ /* jump after the 'match' after the lookahead is successful */
if (dbuf_error(&s->byte_code)) if (dbuf_error(&s->byte_code))
return -1; return -1;
@@ -2176,38 +2142,6 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
if (last_atom_start < 0) { if (last_atom_start < 0) {
return re_parse_error(s, "nothing to repeat"); return re_parse_error(s, "nothing to repeat");
} }
if (greedy) {
int len, pos;
if (quant_max > 0) {
/* specific optimization for simple quantifiers */
if (dbuf_error(&s->byte_code))
goto out_of_memory;
len = re_is_simple_quantifier(s->byte_code.buf + last_atom_start,
s->byte_code.size - last_atom_start);
if (len > 0) {
re_emit_op(s, REOP_match);
if (dbuf_insert(&s->byte_code, last_atom_start, 17))
goto out_of_memory;
pos = last_atom_start;
s->byte_code.buf[pos++] = REOP_simple_greedy_quant;
put_u32(&s->byte_code.buf[pos],
s->byte_code.size - last_atom_start - 17);
pos += 4;
put_u32(&s->byte_code.buf[pos], quant_min);
pos += 4;
put_u32(&s->byte_code.buf[pos], quant_max);
pos += 4;
put_u32(&s->byte_code.buf[pos], len);
pos += 4;
goto done;
}
}
if (dbuf_error(&s->byte_code))
goto out_of_memory;
}
/* the spec tells that if there is no advance when /* the spec tells that if there is no advance when
running the atom after the first quant_min times, running the atom after the first quant_min times,
then there is no match. We remove this test when we then there is no match. We remove this test when we
@@ -2232,34 +2166,37 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
s->byte_code.size = last_atom_start; s->byte_code.size = last_atom_start;
} else if (quant_max == 1 || quant_max == INT32_MAX) { } else if (quant_max == 1 || quant_max == INT32_MAX) {
BOOL has_goto = (quant_max == INT32_MAX); BOOL has_goto = (quant_max == INT32_MAX);
if (dbuf_insert(&s->byte_code, last_atom_start, 5 + add_zero_advance_check)) if (dbuf_insert(&s->byte_code, last_atom_start, 5 + add_zero_advance_check * 2))
goto out_of_memory; goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_split_goto_first + s->byte_code.buf[last_atom_start] = REOP_split_goto_first +
greedy; greedy;
put_u32(s->byte_code.buf + last_atom_start + 1, put_u32(s->byte_code.buf + last_atom_start + 1,
len + 5 * has_goto + add_zero_advance_check * 2); len + 5 * has_goto + add_zero_advance_check * 2 * 2);
if (add_zero_advance_check) { if (add_zero_advance_check) {
s->byte_code.buf[last_atom_start + 1 + 4] = REOP_push_char_pos; s->byte_code.buf[last_atom_start + 1 + 4] = REOP_push_char_pos;
re_emit_op(s, REOP_check_advance); s->byte_code.buf[last_atom_start + 1 + 4 + 1] = 0;
re_emit_op_u8(s, REOP_check_advance, 0);
} }
if (has_goto) if (has_goto)
re_emit_goto(s, REOP_goto, last_atom_start); re_emit_goto(s, REOP_goto, last_atom_start);
} else { } else {
if (dbuf_insert(&s->byte_code, last_atom_start, 10 + add_zero_advance_check)) if (dbuf_insert(&s->byte_code, last_atom_start, 11 + add_zero_advance_check * 2))
goto out_of_memory; goto out_of_memory;
pos = last_atom_start; pos = last_atom_start;
s->byte_code.buf[pos++] = REOP_push_i32; s->byte_code.buf[pos++] = REOP_push_i32;
s->byte_code.buf[pos++] = 0;
put_u32(s->byte_code.buf + pos, quant_max); put_u32(s->byte_code.buf + pos, quant_max);
pos += 4; pos += 4;
s->byte_code.buf[pos++] = REOP_split_goto_first + greedy; s->byte_code.buf[pos++] = REOP_split_goto_first + greedy;
put_u32(s->byte_code.buf + pos, len + 5 + add_zero_advance_check * 2); put_u32(s->byte_code.buf + pos, len + 6 + add_zero_advance_check * 2 * 2);
pos += 4; pos += 4;
if (add_zero_advance_check) { if (add_zero_advance_check) {
s->byte_code.buf[pos++] = REOP_push_char_pos; s->byte_code.buf[pos++] = REOP_push_char_pos;
re_emit_op(s, REOP_check_advance); s->byte_code.buf[pos++] = 0;
re_emit_op_u8(s, REOP_check_advance, 0);
} }
re_emit_goto(s, REOP_loop, last_atom_start + 5); re_emit_goto_u8(s, REOP_loop, 0, last_atom_start + 6);
re_emit_op(s, REOP_drop);
} }
} else if (quant_min == 1 && quant_max == INT32_MAX && } else if (quant_min == 1 && quant_max == INT32_MAX &&
!add_zero_advance_check) { !add_zero_advance_check) {
@@ -2269,39 +2206,39 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
if (quant_min == 1) { if (quant_min == 1) {
/* nothing to add */ /* nothing to add */
} else { } else {
if (dbuf_insert(&s->byte_code, last_atom_start, 5)) if (dbuf_insert(&s->byte_code, last_atom_start, 6))
goto out_of_memory; goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_push_i32; s->byte_code.buf[last_atom_start++] = REOP_push_i32;
put_u32(s->byte_code.buf + last_atom_start + 1, s->byte_code.buf[last_atom_start++] = 0;
quant_min); put_u32(s->byte_code.buf + last_atom_start, quant_min);
last_atom_start += 5; last_atom_start += 4;
re_emit_goto(s, REOP_loop, last_atom_start); re_emit_goto_u8(s, REOP_loop, 0, last_atom_start);
re_emit_op(s, REOP_drop);
} }
if (quant_max == INT32_MAX) { if (quant_max == INT32_MAX) {
pos = s->byte_code.size; pos = s->byte_code.size;
re_emit_op_u32(s, REOP_split_goto_first + greedy, re_emit_op_u32(s, REOP_split_goto_first + greedy,
len + 5 + add_zero_advance_check * 2); len + 5 + add_zero_advance_check * 2 * 2);
if (add_zero_advance_check) if (add_zero_advance_check)
re_emit_op(s, REOP_push_char_pos); re_emit_op_u8(s, REOP_push_char_pos, 0);
/* copy the atom */ /* copy the atom */
dbuf_put_self(&s->byte_code, last_atom_start, len); dbuf_put_self(&s->byte_code, last_atom_start, len);
if (add_zero_advance_check) if (add_zero_advance_check)
re_emit_op(s, REOP_check_advance); re_emit_op_u8(s, REOP_check_advance, 0);
re_emit_goto(s, REOP_goto, pos); re_emit_goto(s, REOP_goto, pos);
} else if (quant_max > quant_min) { } else if (quant_max > quant_min) {
re_emit_op_u32(s, REOP_push_i32, quant_max - quant_min); re_emit_op_u8(s, REOP_push_i32, 0);
dbuf_put_u32(&s->byte_code, quant_max - quant_min);
pos = s->byte_code.size; pos = s->byte_code.size;
re_emit_op_u32(s, REOP_split_goto_first + greedy, re_emit_op_u32(s, REOP_split_goto_first + greedy,
len + 5 + add_zero_advance_check * 2); len + 6 + add_zero_advance_check * 2 * 2);
if (add_zero_advance_check) if (add_zero_advance_check)
re_emit_op(s, REOP_push_char_pos); re_emit_op_u8(s, REOP_push_char_pos, 0);
/* copy the atom */ /* copy the atom */
dbuf_put_self(&s->byte_code, last_atom_start, len); dbuf_put_self(&s->byte_code, last_atom_start, len);
if (add_zero_advance_check) if (add_zero_advance_check)
re_emit_op(s, REOP_check_advance); re_emit_op_u8(s, REOP_check_advance, 0);
re_emit_goto(s, REOP_loop, pos); re_emit_goto_u8(s, REOP_loop, 0, pos);
re_emit_op(s, REOP_drop);
} }
} }
last_atom_start = -1; last_atom_start = -1;
@@ -2311,7 +2248,6 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
break; break;
} }
} }
done:
s->buf_ptr = p; s->buf_ptr = p;
return 0; return 0;
out_of_memory: out_of_memory:
@@ -2386,8 +2322,9 @@ static int re_parse_disjunction(REParseState *s, BOOL is_backward_dir)
return 0; return 0;
} }
/* the control flow is recursive so the analysis can be linear */ /* the control flow is recursive so the analysis can be linear. As a
static int compute_stack_size(const uint8_t *bc_buf, int bc_buf_len) side effect, the auxiliary stack addresses are computed. */
static int compute_stack_size(uint8_t *bc_buf, int bc_buf_len)
{ {
int stack_size, stack_size_max, pos, opcode, len; int stack_size, stack_size_max, pos, opcode, len;
uint32_t val; uint32_t val;
@@ -2405,6 +2342,7 @@ static int compute_stack_size(const uint8_t *bc_buf, int bc_buf_len)
switch(opcode) { switch(opcode) {
case REOP_push_i32: case REOP_push_i32:
case REOP_push_char_pos: case REOP_push_char_pos:
bc_buf[pos + 1] = stack_size;
stack_size++; stack_size++;
if (stack_size > stack_size_max) { if (stack_size > stack_size_max) {
if (stack_size > STACK_SIZE_MAX) if (stack_size > STACK_SIZE_MAX)
@@ -2412,10 +2350,11 @@ static int compute_stack_size(const uint8_t *bc_buf, int bc_buf_len)
stack_size_max = stack_size; stack_size_max = stack_size;
} }
break; break;
case REOP_drop:
case REOP_check_advance: case REOP_check_advance:
case REOP_loop:
assert(stack_size > 0); assert(stack_size > 0);
stack_size--; stack_size--;
bc_buf[pos + 1] = stack_size;
break; break;
case REOP_range: case REOP_range:
case REOP_range_i: case REOP_range_i:
@@ -2638,23 +2577,26 @@ static BOOL is_word_char(uint32_t c)
} \ } \
} while (0) } while (0)
typedef uintptr_t StackInt;
typedef enum { typedef enum {
RE_EXEC_STATE_SPLIT, RE_EXEC_STATE_SPLIT,
RE_EXEC_STATE_LOOKAHEAD, RE_EXEC_STATE_LOOKAHEAD,
RE_EXEC_STATE_NEGATIVE_LOOKAHEAD, RE_EXEC_STATE_NEGATIVE_LOOKAHEAD,
RE_EXEC_STATE_GREEDY_QUANT,
} REExecStateEnum; } REExecStateEnum;
typedef struct REExecState { #if INTPTR_MAX >= INT64_MAX
REExecStateEnum type : 8; #define BP_TYPE_BITS 3
uint8_t stack_len; #else
size_t count; /* only used for RE_EXEC_STATE_GREEDY_QUANT */ #define BP_TYPE_BITS 2
const uint8_t *cptr; #endif
const uint8_t *pc;
void *buf[0]; typedef union {
} REExecState; uint8_t *ptr;
intptr_t val; /* for bp, the low BP_SHIFT bits store REExecStateEnum */
struct {
uintptr_t val : sizeof(uintptr_t) * 8 - BP_TYPE_BITS;
uintptr_t type : BP_TYPE_BITS;
} bp;
} StackElem;
typedef struct { typedef struct {
const uint8_t *cbuf; const uint8_t *cbuf;
@@ -2667,50 +2609,11 @@ typedef struct {
int interrupt_counter; int interrupt_counter;
void *opaque; /* used for stack overflow check */ void *opaque; /* used for stack overflow check */
size_t state_size; StackElem *stack_buf;
uint8_t *state_stack; size_t stack_size;
size_t state_stack_size; StackElem static_stack_buf[32]; /* static stack to avoid allocation in most cases */
size_t state_stack_len;
} REExecContext; } REExecContext;
static int push_state(REExecContext *s,
uint8_t **capture,
StackInt *stack, size_t stack_len,
const uint8_t *pc, const uint8_t *cptr,
REExecStateEnum type, size_t count)
{
REExecState *rs;
uint8_t *new_stack;
size_t new_size, i, n;
StackInt *stack_buf;
if (unlikely((s->state_stack_len + 1) > s->state_stack_size)) {
/* reallocate the stack */
new_size = s->state_stack_size * 3 / 2;
if (new_size < 8)
new_size = 8;
new_stack = lre_realloc(s->opaque, s->state_stack, new_size * s->state_size);
if (!new_stack)
return -1;
s->state_stack_size = new_size;
s->state_stack = new_stack;
}
rs = (REExecState *)(s->state_stack + s->state_stack_len * s->state_size);
s->state_stack_len++;
rs->type = type;
rs->count = count;
rs->stack_len = stack_len;
rs->cptr = cptr;
rs->pc = pc;
n = 2 * s->capture_count;
for(i = 0; i < n; i++)
rs->buf[i] = capture[i];
stack_buf = (StackInt *)(rs->buf + n);
for(i = 0; i < stack_len; i++)
stack_buf[i] = stack[i];
return 0;
}
static int lre_poll_timeout(REExecContext *s) static int lre_poll_timeout(REExecContext *s)
{ {
if (unlikely(--s->interrupt_counter <= 0)) { if (unlikely(--s->interrupt_counter <= 0)) {
@@ -2721,95 +2624,188 @@ static int lre_poll_timeout(REExecContext *s)
return 0; return 0;
} }
static no_inline int stack_realloc(REExecContext *s, size_t n)
{
StackElem *new_stack;
size_t new_size;
new_size = s->stack_size * 3 / 2;
if (new_size < n)
new_size = n;
if (s->stack_buf == s->static_stack_buf) {
new_stack = lre_realloc(s->opaque, NULL, new_size * sizeof(StackElem));
if (!new_stack)
return -1;
/* XXX: could use correct size */
memcpy(new_stack, s->stack_buf, s->stack_size * sizeof(StackElem));
} else {
new_stack = lre_realloc(s->opaque, s->stack_buf, new_size * sizeof(StackElem));
if (!new_stack)
return -1;
}
s->stack_size = new_size;
s->stack_buf = new_stack;
return 0;
}
/* return 1 if match, 0 if not match or < 0 if error. */ /* return 1 if match, 0 if not match or < 0 if error. */
static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture, static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
StackInt *stack, int stack_len, uint8_t **aux_stack, const uint8_t *pc, const uint8_t *cptr)
const uint8_t *pc, const uint8_t *cptr,
BOOL no_recurse)
{ {
int opcode, ret; int opcode;
int cbuf_type; int cbuf_type;
uint32_t val, c; uint32_t val, c, idx;
const uint8_t *cbuf_end; const uint8_t *cbuf_end;
StackElem *sp, *bp, *stack_end;
#ifdef DUMP_EXEC
const uint8_t *pc_start = pc; /* TEST */
#endif
cbuf_type = s->cbuf_type; cbuf_type = s->cbuf_type;
cbuf_end = s->cbuf_end; cbuf_end = s->cbuf_end;
sp = s->stack_buf;
bp = s->stack_buf;
stack_end = s->stack_buf + s->stack_size;
#define CHECK_STACK_SPACE(n) \
if (unlikely((stack_end - sp) < (n))) { \
size_t saved_sp = sp - s->stack_buf; \
size_t saved_bp = bp - s->stack_buf; \
if (stack_realloc(s, sp - s->stack_buf + (n))) \
return LRE_RET_MEMORY_ERROR; \
stack_end = s->stack_buf + s->stack_size; \
sp = s->stack_buf + saved_sp; \
bp = s->stack_buf + saved_bp; \
}
/* XXX: could test if the value was saved to reduce the stack size
but slower */
#define SAVE_CAPTURE(idx, value) \
{ \
CHECK_STACK_SPACE(2); \
sp[0].val = idx; \
sp[1].ptr = capture[idx]; \
sp += 2; \
capture[idx] = (value); \
}
/* avoid saving the previous value if already saved */
#define SAVE_AUX_STACK(idx, value) \
{ \
StackElem *sp1; \
sp1 = sp; \
for(;;) { \
if (sp1 > bp) { \
if (sp1[-2].val == -(int)(idx + 1)) \
break; \
sp1 -= 2; \
} else { \
CHECK_STACK_SPACE(2); \
sp[0].val = -(int)(idx + 1); \
sp[1].ptr = aux_stack[idx]; \
sp += 2; \
break; \
} \
} \
aux_stack[idx] = (value); \
}
#ifdef DUMP_EXEC
printf("%5s %5s %5s %5s %s\n", "PC", "CP", "BP", "SP", "OPCODE");
#endif
for(;;) { for(;;) {
// printf("top=%p: pc=%d\n", th_list.top, (int)(pc - (bc_buf + RE_HEADER_LEN)));
opcode = *pc++; opcode = *pc++;
#ifdef DUMP_EXEC
printf("%5ld %5ld %5ld %5ld %s\n",
pc - 1 - pc_start,
cbuf_type == 0 ? cptr - s->cbuf : (cptr - s->cbuf) / 2,
bp - s->stack_buf,
sp - s->stack_buf,
reopcode_info[opcode].name);
#endif
switch(opcode) { switch(opcode) {
case REOP_match: case REOP_match:
{ return 1;
REExecState *rs; no_match:
if (no_recurse) for(;;) {
return (intptr_t)cptr; REExecStateEnum type;
ret = 1; if (bp == s->stack_buf)
goto recurse;
no_match:
if (no_recurse)
return 0; return 0;
ret = 0; /* undo the modifications to capture[] and aux_stack[] */
recurse: while (sp > bp) {
intptr_t idx2 = sp[-2].val;
if (idx2 >= 0)
capture[idx2] = sp[-1].ptr;
else
aux_stack[-idx2 + 1] = sp[-1].ptr;
sp -= 2;
}
pc = sp[-3].ptr;
cptr = sp[-2].ptr;
type = sp[-1].bp.type;
bp = s->stack_buf + sp[-1].bp.val;
sp -= 3;
if (type != RE_EXEC_STATE_LOOKAHEAD)
break;
}
break;
case REOP_lookahead_match:
/* pop all the saved states until reaching the start of
the lookahead and keep the updated captures and
variables and the corresponding undo info. */
{
StackElem *sp1, *sp_top, *next_sp;
REExecStateEnum type;
sp_top = sp;
for(;;) { for(;;) {
if (lre_poll_timeout(s)) sp1 = sp;
return LRE_RET_TIMEOUT; sp = bp;
if (s->state_stack_len == 0) pc = sp[-3].ptr;
return ret; cptr = sp[-2].ptr;
rs = (REExecState *)(s->state_stack + type = sp[-1].bp.type;
(s->state_stack_len - 1) * s->state_size); bp = s->stack_buf + sp[-1].bp.val;
if (rs->type == RE_EXEC_STATE_SPLIT) { sp[-1].ptr = (void *)sp1; /* save the next value for the copy step */
if (!ret) { sp -= 3;
pop_state: if (type == RE_EXEC_STATE_LOOKAHEAD)
memcpy(capture, rs->buf, break;
sizeof(capture[0]) * 2 * s->capture_count); }
pop_state1: if (sp != s->stack_buf) {
pc = rs->pc; /* keep the undo info if there is a saved state */
cptr = rs->cptr; sp1 = sp;
stack_len = rs->stack_len; while (sp1 < sp_top) {
memcpy(stack, rs->buf + 2 * s->capture_count, next_sp = (void *)sp1[2].ptr;
stack_len * sizeof(stack[0])); sp1 += 3;
s->state_stack_len--; while (sp1 < next_sp)
break; *sp++ = *sp1++;
}
} else if (rs->type == RE_EXEC_STATE_GREEDY_QUANT) {
if (!ret) {
uint32_t char_count, i;
memcpy(capture, rs->buf,
sizeof(capture[0]) * 2 * s->capture_count);
stack_len = rs->stack_len;
memcpy(stack, rs->buf + 2 * s->capture_count,
stack_len * sizeof(stack[0]));
pc = rs->pc;
cptr = rs->cptr;
/* go backward */
char_count = get_u32(pc + 12);
for(i = 0; i < char_count; i++) {
PREV_CHAR(cptr, s->cbuf, cbuf_type);
}
pc = (pc + 16) + (int)get_u32(pc);
rs->cptr = cptr;
rs->count--;
if (rs->count == 0) {
s->state_stack_len--;
}
break;
}
} else {
ret = ((rs->type == RE_EXEC_STATE_LOOKAHEAD && ret) ||
(rs->type == RE_EXEC_STATE_NEGATIVE_LOOKAHEAD && !ret));
if (ret) {
/* keep the capture in case of positive lookahead */
if (rs->type == RE_EXEC_STATE_LOOKAHEAD)
goto pop_state1;
else
goto pop_state;
}
} }
s->state_stack_len--;
} }
} }
break; break;
case REOP_negative_lookahead_match:
/* pop all the saved states until reaching start of the negative lookahead */
for(;;) {
REExecStateEnum type;
type = bp[-1].bp.type;
/* undo the modifications to capture[] and aux_stack[] */
while (sp > bp) {
intptr_t idx2 = sp[-2].val;
if (idx2 >= 0)
capture[idx2] = sp[-1].ptr;
else
aux_stack[-idx2 + 1] = sp[-1].ptr;
sp -= 2;
}
pc = sp[-3].ptr;
cptr = sp[-2].ptr;
type = sp[-1].bp.type;
bp = s->stack_buf + sp[-1].bp.val;
sp -= 3;
if (type == RE_EXEC_STATE_NEGATIVE_LOOKAHEAD)
break;
}
goto no_match;
case REOP_char32: case REOP_char32:
case REOP_char32_i: case REOP_char32_i:
val = get_u32(pc); val = get_u32(pc);
@@ -2842,24 +2838,40 @@ static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
pc1 = pc; pc1 = pc;
pc = pc + (int)val; pc = pc + (int)val;
} }
ret = push_state(s, capture, stack, stack_len, CHECK_STACK_SPACE(3);
pc1, cptr, RE_EXEC_STATE_SPLIT, 0); sp[0].ptr = (uint8_t *)pc1;
if (ret < 0) sp[1].ptr = (uint8_t *)cptr;
return LRE_RET_MEMORY_ERROR; sp[2].bp.val = bp - s->stack_buf;
break; sp[2].bp.type = RE_EXEC_STATE_SPLIT;
sp += 3;
bp = sp;
} }
break;
case REOP_lookahead: case REOP_lookahead:
case REOP_negative_lookahead: case REOP_negative_lookahead:
val = get_u32(pc); val = get_u32(pc);
pc += 4; pc += 4;
ret = push_state(s, capture, stack, stack_len, if (opcode == REOP_lookahead && bp != s->stack_buf && 0) {
pc + (int)val, cptr, int i;
RE_EXEC_STATE_LOOKAHEAD + opcode - REOP_lookahead, /* save all the capture state so that they can be
0); restored in case of failure after the lookahead
if (ret < 0) matches */
return LRE_RET_MEMORY_ERROR; idx = 4 * s->capture_count;
CHECK_STACK_SPACE(idx);
for(i = 0; i < 2 * s->capture_count; i++) {
sp[0].val = i;
sp[1].ptr = capture[i];
sp += 2;
}
}
CHECK_STACK_SPACE(3);
sp[0].ptr = (uint8_t *)(pc + (int)val);
sp[1].ptr = (uint8_t *)cptr;
sp[2].bp.val = bp - s->stack_buf;
sp[2].bp.type = RE_EXEC_STATE_LOOKAHEAD + opcode - REOP_lookahead;
sp += 3;
bp = sp;
break; break;
case REOP_goto: case REOP_goto:
val = get_u32(pc); val = get_u32(pc);
pc += 4 + (int)val; pc += 4 + (int)val;
@@ -2902,7 +2914,8 @@ static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
case REOP_save_end: case REOP_save_end:
val = *pc++; val = *pc++;
assert(val < s->capture_count); assert(val < s->capture_count);
capture[2 * val + opcode - REOP_save_start] = (uint8_t *)cptr; idx = 2 * val + opcode - REOP_save_start;
SAVE_CAPTURE(idx, (uint8_t *)cptr);
break; break;
case REOP_save_reset: case REOP_save_reset:
{ {
@@ -2911,35 +2924,47 @@ static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
val2 = pc[1]; val2 = pc[1];
pc += 2; pc += 2;
assert(val2 < s->capture_count); assert(val2 < s->capture_count);
CHECK_STACK_SPACE(2 * (val2 - val + 1));
while (val <= val2) { while (val <= val2) {
capture[2 * val] = NULL; idx = 2 * val;
capture[2 * val + 1] = NULL; SAVE_CAPTURE(idx, NULL);
idx = 2 * val + 1;
SAVE_CAPTURE(idx, NULL);
val++; val++;
} }
} }
break; break;
case REOP_push_i32: case REOP_push_i32:
val = get_u32(pc); idx = pc[0];
pc += 4; val = get_u32(pc + 1);
stack[stack_len++] = val; pc += 5;
break; SAVE_AUX_STACK(idx, (void *)(uintptr_t)val);
case REOP_drop:
stack_len--;
break; break;
case REOP_loop: case REOP_loop:
val = get_u32(pc); {
pc += 4; uint32_t val2;
if (--stack[stack_len - 1] != 0) { idx = pc[0];
pc += (int)val; val = get_u32(pc + 1);
if (lre_poll_timeout(s)) pc += 5;
return LRE_RET_TIMEOUT;
val2 = (uintptr_t)aux_stack[idx] - 1;
SAVE_AUX_STACK(idx, (void *)(uintptr_t)val2);
if (val2 != 0) {
pc += (int)val;
if (lre_poll_timeout(s))
return LRE_RET_TIMEOUT;
}
} }
break; break;
case REOP_push_char_pos: case REOP_push_char_pos:
stack[stack_len++] = (uintptr_t)cptr; idx = pc[0];
pc++;
SAVE_AUX_STACK(idx, (uint8_t *)cptr);
break; break;
case REOP_check_advance: case REOP_check_advance:
if (stack[--stack_len] == (uintptr_t)cptr) idx = pc[0];
pc++;
if (aux_stack[idx] == cptr)
goto no_match; goto no_match;
break; break;
case REOP_word_boundary: case REOP_word_boundary:
@@ -3104,50 +3129,10 @@ static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
goto no_match; goto no_match;
PREV_CHAR(cptr, s->cbuf, cbuf_type); PREV_CHAR(cptr, s->cbuf, cbuf_type);
break; break;
case REOP_simple_greedy_quant:
{
uint32_t next_pos, quant_min, quant_max;
size_t q;
intptr_t res;
const uint8_t *pc1;
next_pos = get_u32(pc);
quant_min = get_u32(pc + 4);
quant_max = get_u32(pc + 8);
pc += 16;
pc1 = pc;
pc += (int)next_pos;
q = 0;
for(;;) {
if (lre_poll_timeout(s))
return LRE_RET_TIMEOUT;
res = lre_exec_backtrack(s, capture, stack, stack_len,
pc1, cptr, TRUE);
if (res == LRE_RET_MEMORY_ERROR ||
res == LRE_RET_TIMEOUT)
return res;
if (!res)
break;
cptr = (uint8_t *)res;
q++;
if (q >= quant_max && quant_max != INT32_MAX)
break;
}
if (q < quant_min)
goto no_match;
if (q > quant_min) {
/* will examine all matches down to quant_min */
ret = push_state(s, capture, stack, stack_len,
pc1 - 16, cptr,
RE_EXEC_STATE_GREEDY_QUANT,
q - quant_min);
if (ret < 0)
return LRE_RET_MEMORY_ERROR;
}
}
break;
default: default:
#ifdef DUMP_EXEC
printf("unknown opcode pc=%ld\n", pc - 1 - pc_start);
#endif
abort(); abort();
} }
} }
@@ -3161,8 +3146,8 @@ int lre_exec(uint8_t **capture,
int cbuf_type, void *opaque) int cbuf_type, void *opaque)
{ {
REExecContext s_s, *s = &s_s; REExecContext s_s, *s = &s_s;
int re_flags, i, alloca_size, ret; int re_flags, i, ret;
StackInt *stack_buf; uint8_t **aux_stack;
const uint8_t *cptr; const uint8_t *cptr;
re_flags = lre_get_flags(bc_buf); re_flags = lre_get_flags(bc_buf);
@@ -3177,17 +3162,12 @@ int lre_exec(uint8_t **capture,
s->interrupt_counter = INTERRUPT_COUNTER_INIT; s->interrupt_counter = INTERRUPT_COUNTER_INIT;
s->opaque = opaque; s->opaque = opaque;
s->state_size = sizeof(REExecState) + s->stack_buf = s->static_stack_buf;
s->capture_count * sizeof(capture[0]) * 2 + s->stack_size = countof(s->static_stack_buf);
s->stack_size_max * sizeof(stack_buf[0]);
s->state_stack = NULL;
s->state_stack_len = 0;
s->state_stack_size = 0;
for(i = 0; i < s->capture_count * 2; i++) for(i = 0; i < s->capture_count * 2; i++)
capture[i] = NULL; capture[i] = NULL;
alloca_size = s->stack_size_max * sizeof(stack_buf[0]); aux_stack = alloca(s->stack_size_max * sizeof(aux_stack[0]));
stack_buf = alloca(alloca_size);
cptr = cbuf + (cindex << cbuf_type); cptr = cbuf + (cindex << cbuf_type);
if (0 < cindex && cindex < clen && s->cbuf_type == 2) { if (0 < cindex && cindex < clen && s->cbuf_type == 2) {
@@ -3197,9 +3177,10 @@ int lre_exec(uint8_t **capture,
} }
} }
ret = lre_exec_backtrack(s, capture, stack_buf, 0, bc_buf + RE_HEADER_LEN, ret = lre_exec_backtrack(s, capture, aux_stack, bc_buf + RE_HEADER_LEN,
cptr, FALSE); cptr);
lre_realloc(s->opaque, s->state_stack, 0); if (s->stack_buf != s->static_stack_buf)
lre_realloc(s->opaque, s->stack_buf, 0);
return ret; return ret;
} }