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regexp: fixed the zero advance logic in quantifiers (github issue #158)

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This commit is contained in:
Fabrice Bellard 2024-01-10 14:36:19 +01:00
parent f25e5d4094
commit 10fc744ae4
4 changed files with 53 additions and 77 deletions
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3
libregexp-opcode.h
View file

@ -50,8 +50,7 @@ DEF(range32, 3) /* variable length */
DEF(lookahead, 5)
DEF(negative_lookahead, 5)
DEF(push_char_pos, 1) /* push the character position on the stack */
DEF(bne_char_pos, 5) /* pop one stack element and jump if equal to the character
position */
DEF(check_advance, 1) /* pop one stack element and check that it is different from the character position */
DEF(prev, 1) /* go to the previous char */
DEF(simple_greedy_quant, 17)

111
libregexp.c
View file

@ -280,7 +280,6 @@ static __maybe_unused void lre_dump_bytecode(const uint8_t *buf,
case REOP_loop:
case REOP_lookahead:
case REOP_negative_lookahead:
case REOP_bne_char_pos:
val = get_u32(buf + pos + 1);
val += (pos + 5);
printf(" %u", val);
@ -888,22 +887,17 @@ static int re_parse_char_class(REParseState *s, const uint8_t **pp)
}
/* Return:
1 if the opcodes in bc_buf[] always advance the character pointer.
0 if the character pointer may not be advanced.
-1 if the code may depend on side effects of its previous execution (backreference)
- true if the opcodes may not advance the char pointer
- false if the opcodes always advance the char pointer
*/
static int re_check_advance(const uint8_t *bc_buf, int bc_buf_len)
static BOOL re_need_check_advance(const uint8_t *bc_buf, int bc_buf_len)
{
int pos, opcode, ret, len, i;
uint32_t val, last;
BOOL has_back_reference;
uint8_t capture_bitmap[CAPTURE_COUNT_MAX];
int pos, opcode, len;
uint32_t val;
BOOL ret;
ret = -2; /* not known yet */
ret = TRUE;
pos = 0;
has_back_reference = FALSE;
memset(capture_bitmap, 0, sizeof(capture_bitmap));
while (pos < bc_buf_len) {
opcode = bc_buf[pos];
len = reopcode_info[opcode].size;
@ -921,8 +915,7 @@ static int re_check_advance(const uint8_t *bc_buf, int bc_buf_len)
case REOP_dot:
case REOP_any:
simple_char:
if (ret == -2)
ret = 1;
ret = FALSE;
break;
case REOP_line_start:
case REOP_line_end:
@ -936,41 +929,16 @@ static int re_check_advance(const uint8_t *bc_buf, int bc_buf_len)
break;
case REOP_save_start:
case REOP_save_end:
val = bc_buf[pos + 1];
capture_bitmap[val] |= 1;
break;
case REOP_save_reset:
{
val = bc_buf[pos + 1];
last = bc_buf[pos + 2];
while (val < last)
capture_bitmap[val++] |= 1;
}
break;
case REOP_back_reference:
case REOP_backward_back_reference:
val = bc_buf[pos + 1];
capture_bitmap[val] |= 2;
has_back_reference = TRUE;
break;
default:
/* safe behvior: we cannot predict the outcome */
if (ret == -2)
ret = 0;
break;
return TRUE;
}
pos += len;
}
if (has_back_reference) {
/* check if there is back reference which references a capture
made in the some code */
for(i = 0; i < CAPTURE_COUNT_MAX; i++) {
if (capture_bitmap[i] == 3)
return -1;
}
}
if (ret == -2)
ret = 0;
return ret;
}
@ -1541,8 +1509,12 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
if (dbuf_error(&s->byte_code))
goto out_of_memory;
add_zero_advance_check = (re_check_advance(s->byte_code.buf + last_atom_start,
s->byte_code.size - last_atom_start) == 0);
/* the spec tells that if there is no advance when
running the atom after the first quant_min times,
then there is no match. We remove this test when we
are sure the atom always advances the position. */
add_zero_advance_check = re_need_check_advance(s->byte_code.buf + last_atom_start,
s->byte_code.size - last_atom_start);
} else {
add_zero_advance_check = FALSE;
}
@ -1562,38 +1534,34 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
}
if (quant_max == 0) {
s->byte_code.size = last_atom_start;
} else if (quant_max == 1) {
if (dbuf_insert(&s->byte_code, last_atom_start, 5))
goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_split_goto_first +
greedy;
put_u32(s->byte_code.buf + last_atom_start + 1, len);
} else if (quant_max == INT32_MAX) {
} else if (quant_max == 1 || 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))
goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_split_goto_first +
greedy;
put_u32(s->byte_code.buf + last_atom_start + 1,
len + 5 + add_zero_advance_check);
len + 5 * has_goto + add_zero_advance_check * 2);
if (add_zero_advance_check) {
/* avoid infinite loop by stoping the
recursion if no advance was made in the
atom (only works if the atom has no
side effect) */
s->byte_code.buf[last_atom_start + 1 + 4] = REOP_push_char_pos;
re_emit_goto(s, REOP_bne_char_pos, last_atom_start);
} else {
re_emit_goto(s, REOP_goto, last_atom_start);
re_emit_op(s, REOP_check_advance);
}
if (has_goto)
re_emit_goto(s, REOP_goto, last_atom_start);
} else {
if (dbuf_insert(&s->byte_code, last_atom_start, 10))
if (dbuf_insert(&s->byte_code, last_atom_start, 10 + add_zero_advance_check))
goto out_of_memory;
pos = last_atom_start;
s->byte_code.buf[pos++] = REOP_push_i32;
put_u32(s->byte_code.buf + pos, quant_max);
pos += 4;
s->byte_code.buf[pos++] = REOP_split_goto_first + greedy;
put_u32(s->byte_code.buf + pos, len + 5);
put_u32(s->byte_code.buf + pos, len + 5 + add_zero_advance_check * 2);
pos += 4;
if (add_zero_advance_check) {
s->byte_code.buf[pos++] = REOP_push_char_pos;
re_emit_op(s, REOP_check_advance);
}
re_emit_goto(s, REOP_loop, last_atom_start + 5);
re_emit_op(s, REOP_drop);
}
@ -1617,22 +1585,25 @@ static int re_parse_term(REParseState *s, BOOL is_backward_dir)
if (quant_max == INT32_MAX) {
pos = s->byte_code.size;
re_emit_op_u32(s, REOP_split_goto_first + greedy,
len + 5 + add_zero_advance_check);
len + 5 + add_zero_advance_check * 2);
if (add_zero_advance_check)
re_emit_op(s, REOP_push_char_pos);
/* copy the atom */
dbuf_put_self(&s->byte_code, last_atom_start, len);
if (add_zero_advance_check)
re_emit_goto(s, REOP_bne_char_pos, pos);
else
re_emit_op(s, REOP_check_advance);
re_emit_goto(s, REOP_goto, pos);
} else if (quant_max > quant_min) {
re_emit_op_u32(s, REOP_push_i32, quant_max - quant_min);
pos = s->byte_code.size;
re_emit_op_u32(s, REOP_split_goto_first + greedy, len + 5);
re_emit_op_u32(s, REOP_split_goto_first + greedy,
len + 5 + add_zero_advance_check * 2);
if (add_zero_advance_check)
re_emit_op(s, REOP_push_char_pos);
/* copy the atom */
dbuf_put_self(&s->byte_code, last_atom_start, len);
if (add_zero_advance_check)
re_emit_op(s, REOP_check_advance);
re_emit_goto(s, REOP_loop, pos);
re_emit_op(s, REOP_drop);
}
@ -1746,7 +1717,7 @@ static int compute_stack_size(const uint8_t *bc_buf, int bc_buf_len)
}
break;
case REOP_drop:
case REOP_bne_char_pos:
case REOP_check_advance:
assert(stack_size > 0);
stack_size--;
break;
@ -2242,11 +2213,9 @@ static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
case REOP_push_char_pos:
stack[stack_len++] = (uintptr_t)cptr;
break;
case REOP_bne_char_pos:
val = get_u32(pc);
pc += 4;
if (stack[--stack_len] != (uintptr_t)cptr)
pc += (int)val;
case REOP_check_advance:
if (stack[--stack_len] == (uintptr_t)cptr)
goto no_match;
break;
case REOP_word_boundary:
case REOP_not_word_boundary:

2
test262_errors.txt
View file

@ -1,6 +1,4 @@
test262/test/annexB/language/eval-code/direct/script-decl-lex-collision-in-sloppy-mode.js:13: Test262Error: Expected a SyntaxError to be thrown but no exception was thrown at all
test262/test/built-ins/RegExp/lookahead-quantifier-match-groups.js:27: Test262Error: Expected [a, abc] and [a, undefined] to have the same contents. ? quantifier
test262/test/built-ins/RegExp/lookahead-quantifier-match-groups.js:27: strict mode: Test262Error: Expected [a, abc] and [a, undefined] to have the same contents. ? quantifier
test262/test/language/expressions/assignment/target-member-computed-reference-null.js:32: Test262Error: Expected a DummyError but got a TypeError
test262/test/language/expressions/assignment/target-member-computed-reference-null.js:32: strict mode: Test262Error: Expected a DummyError but got a TypeError
test262/test/language/expressions/assignment/target-member-computed-reference-undefined.js:32: Test262Error: Expected a DummyError but got a TypeError

10
tests/test_builtin.js
View file

@ -539,6 +539,16 @@ function test_regexp()
assert(/{1a}/.toString(), "/{1a}/");
a = /a{1+/.exec("a{11");
assert(a, ["a{11"]);
/* test zero length matches */
a = /(?:(?=(abc)))a/.exec("abc");
assert(a, ["a", "abc"]);
a = /(?:(?=(abc)))?a/.exec("abc");
assert(a, ["a", undefined]);
a = /(?:(?=(abc))){0,2}a/.exec("abc");
assert(a, ["a", undefined]);
a = /(?:|[\w])+([0-9])/.exec("123a23");
assert(a, ["123a23", "3"]);
}
function test_symbol()