diff options
Diffstat (limited to 'posix/regexec.c')
| -rw-r--r-- | posix/regexec.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/posix/regexec.c b/posix/regexec.c index 79104119be..a03df2636a 100644 --- a/posix/regexec.c +++ b/posix/regexec.c @@ -1885,7 +1885,12 @@ check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx, from_node, bkref_idx) { int dst, cpos; - if (ent->node != node || ent->subexp_from != ent->subexp_to) + if (ent->node != node) + continue; + + if (subexp_idx <= 8 * sizeof (ent->eps_reachable_subexps_map) + && (ent->eps_reachable_subexps_map + & (1 << (subexp_idx - 1))) == 0) continue; /* Recurse trying to reach the OP_OPEN_SUBEXP and @@ -1906,11 +1911,13 @@ check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx, from_node, bkref_idx) cpos = check_dst_limits_calc_pos_1 (mctx, boundaries, subexp_idx, dst, bkref_idx); - if (cpos == -1 && (boundaries & 1)) + if (cpos == -1 /* && (boundaries & 1) */) return -1; - if (cpos == 0 /* && (boundaries & 2) */) + if (cpos == 0 && (boundaries & 2)) return 0; + + ent->eps_reachable_subexps_map &= ~(1 << (subexp_idx - 1)); } while (ent++->more); break; @@ -4169,6 +4176,18 @@ match_ctx_add_entry (mctx, node, str_idx, from, to) mctx->bkref_ents[mctx->nbkref_ents].str_idx = str_idx; mctx->bkref_ents[mctx->nbkref_ents].subexp_from = from; mctx->bkref_ents[mctx->nbkref_ents].subexp_to = to; + + /* This is a cache that saves negative results of check_dst_limits_calc_pos. + If bit N is clear, means that this entry won't epsilon-transition to + an OP_OPEN_SUBEXP or OP_CLOSE_SUBEXP for the N+1-th subexpression. If + it is set, check_dst_limits_calc_pos_1 will recurse and try to find one + such node. + + A backreference does not epsilon-transition unless it is empty, so set + to all zeros if FROM != TO. */ + mctx->bkref_ents[mctx->nbkref_ents].eps_reachable_subexps_map + = (from == to ? ~0 : 0); + mctx->bkref_ents[mctx->nbkref_ents++].more = 0; if (mctx->max_mb_elem_len < to - from) mctx->max_mb_elem_len = to - from; |