From b6b65d49fc75b4865cbbcc4650310da509dcb760 Mon Sep 17 00:00:00 2001
From: Ulya Trofimovich <skvadrik@gmail.com>
Date: Sun, 16 Apr 2017 11:10:25 +0100
Subject: [PATCH] Command normalization: update pointer to last command, it
 might change.

If normalization of 'save' commands removes the last 'save' command,
then pointer to 'next' will point to the 'next' field of the removed
command and the chain of commands will break.
---
 re2c/src/dfa/cfg/normalize.cc | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/re2c/src/dfa/cfg/normalize.cc b/re2c/src/dfa/cfg/normalize.cc
index 90ec7bf0..fcc7e0a5 100644
--- a/re2c/src/dfa/cfg/normalize.cc
+++ b/re2c/src/dfa/cfg/normalize.cc
@@ -17,7 +17,7 @@ template<typename cmd_t> void normalize(cmd_t *cmd);
  * For that reason all commands are normalized.
  */
 
-static void normalize(tcmd_t *s, tcmd_t *e);
+static tcmd_t **normalize(tcmd_t **ps, tcmd_t *e);
 
 void cfg_t::normalization(cfg_t &cfg)
 {
@@ -33,20 +33,19 @@ void cfg_t::normalization(cfg_t &cfg)
 		// Therefore we split the list in continuous sublists of
 		// 'copy', 'save without history' and 'save with history'
 		// commands and normalize each sublist in a proper way.
-		tcmd_t **px, **py, *x;
+		tcmd_t **px, *x;
 		for (px = &b->cmd; (x = *px);) {
 			if (tcmd_t::iscopy(x)) {
-				for (py = px; (x = *px) && tcmd_t::iscopy(x); px = &x->next);
-				*px = NULL;
-				normalize(*py, NULL);
-				tcmd_t::topsort(py, indeg);
-				for (px = py; *px; px = &(*px)->next);
-				*px = x;
+				for (x = *px; x && tcmd_t::iscopy(x); x = x->next);
+				*normalize(px, x) = NULL; // topsort expects NULL terminator
+				tcmd_t::topsort(px, indeg);
+				for (; *px; px = &(*px)->next); // find tail
+				*px = x; // restore tail
 			} else if (tcmd_t::isset(x)) {
-				for (py = px; (x = *px) && tcmd_t::isset(x); px = &x->next);
-				normalize(*py, x);
+				for (x = *px; x && tcmd_t::isset(x); x = x->next);
+				px = normalize(px, x);
 			} else {
-				for (py = px; (x = *px) && tcmd_t::isadd(x); px = &x->next);
+				for (; (x = *px) && tcmd_t::isadd(x); px = &x->next);
 				// don't normalize, histories may have complex dependencies
 			}
 		}
@@ -83,10 +82,10 @@ static bool less(const tcmd_t &x, const tcmd_t &y)
 	return false;
 }
 
-void normalize(tcmd_t *s, tcmd_t *e)
+tcmd_t **normalize(tcmd_t **ps, tcmd_t *e)
 {
 	// sort lexicographically
-	for (tcmd_t *p = s; p != e; p = p->next) {
+	for (tcmd_t *p = *ps; p != e; p = p->next) {
 		for (tcmd_t *q = p->next; q != e; q = q->next) {
 			if (less(*q, *p)) {
 				swap(*p, *q);
@@ -95,7 +94,7 @@ void normalize(tcmd_t *s, tcmd_t *e)
 	}
 
 	// delete duplicates
-	for (tcmd_t *p = s; p != e;) {
+	for (tcmd_t *p = *ps; p != e;) {
 		tcmd_t *q = p->next;
 		if (q != e && tcmd_t::equal(*p, *q)) {
 			p->next = q->next;
@@ -103,6 +102,9 @@ void normalize(tcmd_t *s, tcmd_t *e)
 			p = q;
 		}
 	}
+
+	for (; *ps != e; ps = &(*ps)->next);
+	return ps;
 }
 
 } // namespace re2c
-- 
2.40.0