From: Ulya Trofimovich <skvadrik@gmail.com>
Date: Tue, 27 Jun 2017 13:05:26 +0000 (+0100)
Subject: Skip (non-orbit) start tags during POSIX disambiguation.
X-Git-Tag: 1.0~39^2~39
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7d6934e691f7c1796c6b7cbc0f5e2629b77ff59f;p=re2c

Skip (non-orbit) start tags during POSIX disambiguation.

Their position is fixed on some higher-priority tag (except the very
first tag, but in RE2C match is always anchored).
We cannot skip orbit start tag because the corresponding orbit end tag
is hoisted out of loop (by construction) and is, in fact, non-orbit.
---

diff --git a/re2c/src/dfa/closure.cc b/re2c/src/dfa/closure.cc
index aa01c227..0f9ac97a 100644
--- a/re2c/src/dfa/closure.cc
+++ b/re2c/src/dfa/closure.cc
@@ -64,6 +64,14 @@ static int32_t cmp_leftmost(const clos_t &x, const clos_t &y, Tagpool &tagpool)
 	return tagpool.history.compare_plain(x.index, y.index, Tag::RIGHTMOST);
 }
 
+// Skip non-orbit start tags: their position is fixed on some higher-priority
+// tag (except the very first tag, but in RE2C match is always anchored).
+// We cannot skip orbit start tag because the corresponding orbit end tag is
+// hoisted out of loop (by construction) and is, in fact, non-orbit.
+static bool redundant(size_t t, const std::vector<Tag> &tags) {
+	return (t % 2 == 0) != orbit(tags[t]);
+}
+
 /* note [epsilon-closures in tagged NFA]
  *
  * The closure includes all NFA states that are reachable by epsilon-paths
@@ -242,6 +250,7 @@ bool better(const clos_t &c1, const clos_t &c2,
 	} else {
 		tagtree_t &h = tagpool.history;
 		for (size_t t = 0; t < tagpool.ntags; ++t) {
+			if (redundant(t, tags)) continue;
 			const hidx_t i1 = c1.tlook, i2 = c2.tlook;
 			const tagver_t
 				o1 = -tagpool[c1.order][t],
@@ -442,15 +451,17 @@ void orders(closure_t &clos, Tagpool &tagpool, const std::vector<Tag> &tags)
 	pe = ps;
 	for (c = b; c != e; ++c) *pe++ = c;
 
+	memset(os, 0, ntag * nclos * sizeof(tagver_t));
 	if (!tagpool.opts->posix_captures) {
 		cmp_leftmost_t cmp = {tagpool};
 		assign_orders(ps, pe, os0, cmp);
 		o = os;
 		for (c = b; c != e; ++c, o += ntag) {
-			std::fill(o, o + ntag, os0[std::find(ps, pe, c) - ps]);
+			o[0] = os0[std::find(ps, pe, c) - ps];
 		}
 	} else {
 		for (size_t t = 0; t < ntag; ++t) {
+			if (redundant(t, tags)) continue;
 			cmp_posix_t cmp = {tagpool, t, orbit(tags[t])};
 			assign_orders(ps, pe, os0, cmp);
 			o = os;