From: Jonathan Wakely <jwakely@redhat.com>
Date: Mon, 8 Jun 2015 14:42:02 +0000 (+0100)
Subject: re PR libstdc++/66354 ([UBSAN] stl_algobase.h:708:7: runtime error: null pointer... 
X-Git-Tag: releases/gcc-4.9.3~92
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=942528fbf250a3986079ea312de0c66928f5f536;p=thirdparty%2Fgcc.git

re PR libstdc++/66354 ([UBSAN] stl_algobase.h:708:7: runtime error: null pointer passed as argument)

	PR libstdc++/66354
	* include/bits/stl_algobase.h (__fill_a): Check length before calling
	memset.

	PR libstdc++/66327
	* include/bits/stl_algobase.h (__equal<true>::equal): Do not call
	memcmp for empty ranges.
	(__lexicographical_compare<true>::__lc): Likewise.

From-SVN: r224233
---

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index dc0a5497c5e0..278f4b45d286 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,14 @@
 2015-06-08  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/66354
+	* include/bits/stl_algobase.h (__fill_a): Check length before calling
+	memset.
+
+	PR libstdc++/66327
+	* include/bits/stl_algobase.h (__equal<true>::equal): Do not call
+	memcmp for empty ranges.
+	(__lexicographical_compare<true>::__lc): Likewise.
+
 	Backport from mainline
 	2015-04-13  Jonathan Wakely  <jwakely@redhat.com>
 
diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h
index f7c11e931d7d..a8d3cc89ee3f 100644
--- a/libstdc++-v3/include/bits/stl_algobase.h
+++ b/libstdc++-v3/include/bits/stl_algobase.h
@@ -711,8 +711,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     __fill_a(_Tp* __first, _Tp* __last, const _Tp& __c)
     {
       const _Tp __tmp = __c;
-      __builtin_memset(__first, static_cast<unsigned char>(__tmp),
-		       __last - __first);
+      if (const size_t __len = __last - __first)
+	__builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
     }
 
   /**
@@ -818,8 +818,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
         static bool
         equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
         {
-	  return !__builtin_memcmp(__first1, __first2, sizeof(_Tp)
-				   * (__last1 - __first1));
+	  if (const size_t __len = (__last1 - __first1))
+	    return !__builtin_memcmp(__first1, __first2, sizeof(_Tp) * __len);
+	  return true;
 	}
     };
 
@@ -923,9 +924,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	{
 	  const size_t __len1 = __last1 - __first1;
 	  const size_t __len2 = __last2 - __first2;
-	  const int __result = __builtin_memcmp(__first1, __first2,
-						std::min(__len1, __len2));
-	  return __result != 0 ? __result < 0 : __len1 < __len2;
+	  if (const size_t __len = std::min(__len1, __len2))
+	    if (int __result = __builtin_memcmp(__first1, __first2, __len))
+	      return __result < 0;
+	  return __len1 < __len2;
 	}
     };