From c253f9bd1a7f442fdb1548c6d721d7692c67a4ab Mon Sep 17 00:00:00 2001
From: Ulya Trofimovich <skvadrik@gmail.com>
Date: Mon, 31 Jul 2017 14:22:19 +0100
Subject: [PATCH] Use explicit stack instead of implicit recursion.

With CXXFLAGS='-fsanitize=addres' GCC complains about stack overflow.
---
 re2c/src/re/split_charset.cc | 54 ++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 27 deletions(-)

diff --git a/re2c/src/re/split_charset.cc b/re2c/src/re/split_charset.cc
index 4c1a4b0e..21c282df 100644
--- a/re2c/src/re/split_charset.cc
+++ b/re2c/src/re/split_charset.cc
@@ -1,35 +1,11 @@
 #include "src/util/c99_stdint.h"
 #include <set>
+#include <stack>
 
 #include "src/re/re.h"
 
 namespace re2c {
 
-static void split(const RE* re, std::set<uint32_t> &cs)
-{
-	switch (re->type) {
-		case RE::NIL: break;
-		case RE::TAG: break;
-		case RE::SYM:
-			for (const Range *r = re->sym; r; r = r->next()) {
-				cs.insert(r->lower());
-				cs.insert(r->upper());
-			}
-			break;
-		case RE::ALT:
-			split(re->alt.re1, cs);
-			split(re->alt.re2, cs);
-			break;
-		case RE::CAT:
-			split(re->cat.re1, cs);
-			split(re->cat.re2, cs);
-			break;
-		case RE::ITER:
-			split(re->iter.re, cs);
-			break;
-	}
-}
-
 /* The original set of code units (charset) might be very large.
  * A common trick it is to split charset into disjoint character ranges
  * and choose a representative of each range (we choose lower bound).
@@ -40,12 +16,36 @@ static void split(const RE* re, std::set<uint32_t> &cs)
 void split_charset(RESpec &spec)
 {
 	std::set<uint32_t> cs;
+	std::stack<const RE*> todo;
 
 	std::vector<RE*>::const_iterator
 		i = spec.res.begin(),
 		e = spec.res.end();
-	for (; i != e; ++i) {
-		split(*i, cs);
+	for (; i != e; ++i) todo.push(*i);
+	while (!todo.empty()) {
+		const RE *re = todo.top();
+		todo.pop();
+		switch (re->type) {
+			case RE::NIL: break;
+			case RE::TAG: break;
+			case RE::SYM:
+				for (const Range *r = re->sym; r; r = r->next()) {
+					cs.insert(r->lower());
+					cs.insert(r->upper());
+				}
+				break;
+			case RE::ALT:
+				todo.push(re->alt.re2);
+				todo.push(re->alt.re1);
+				break;
+			case RE::CAT:
+				todo.push(re->cat.re2);
+				todo.push(re->cat.re1);
+				break;
+			case RE::ITER:
+				todo.push(re->iter.re);
+				break;
+		}
 	}
 	cs.insert(0);
 	cs.insert(spec.opts->encoding.nCodeUnits());
-- 
2.40.0