commit 5fdabb72fdcba6bcf788eaa19c1ee557c13b8a7a

Author: Mark Wielaard <mark@klomp.org>

Date:   Sat Dec 1 23:54:40 2018 +0100

    Bug 401627 - Add wcsncmp override and testcase.

    glibc 2.28 added an avx2 optimized variant of wstrncmp which memcheck

    cannot proof correct. Add a simple override in vg_replace_strmem.c.

diff --git a/memcheck/tests/wcs.c b/memcheck/tests/wcs.c

index 15730ad..538304b 100644

--- a/memcheck/tests/wcs.c

+++ b/memcheck/tests/wcs.c

@@ -1,5 +1,6 @@

-// Uses various wchar_t * functions that have hand written SSE assembly

-// implementations in glibc. wcslen, wcscpy, wcscmp, wcsrchr, wcschr.

+// Uses various wchar_t * functions that have hand written SSE and/or AVX2

+// assembly implementations in glibc.

+// wcslen, wcscpy, wcscmp, wcsncmp, wcsrchr, wcschr.

 #include <stdio.h>

 #include <stdlib.h>

@@ -18,6 +19,8 @@ int main(int argc, char **argv)

   c = wcscpy (b, a);

   fprintf (stderr, "wcscmp equal: %d\n", wcscmp (a, b)); // wcscmp equal: 0

+  fprintf (stderr,

+	   "wcsncmp equal: %d\n", wcsncmp (a, b, l)); // wcsncmp equal: 0

   d = wcsrchr (a, L'd');

   e = wcschr (a, L'd');

diff --git a/memcheck/tests/wcs.stderr.exp b/memcheck/tests/wcs.stderr.exp

index 41d74c8..d5b5959 100644

--- a/memcheck/tests/wcs.stderr.exp

+++ b/memcheck/tests/wcs.stderr.exp

@@ -1,3 +1,4 @@

 wcslen: 53

 wcscmp equal: 0

+wcsncmp equal: 0

 wcsrchr == wcschr: 1

diff --git a/shared/vg_replace_strmem.c b/shared/vg_replace_strmem.c

index d6927f0..89a7dcc 100644

--- a/shared/vg_replace_strmem.c

+++ b/shared/vg_replace_strmem.c

@@ -103,6 +103,7 @@

    20420 STPNCPY

    20430 WMEMCHR

    20440 WCSNLEN

+   20450 WSTRNCMP

 */

 #if defined(VGO_solaris)

@@ -1927,6 +1928,36 @@ static inline void my_exit ( int x )

  WCSCMP(VG_Z_LIBC_SONAME,          wcscmp)

 #endif

+/*---------------------- wcsncmp ----------------------*/

+

+// This is a wchar_t equivalent to strncmp.  We don't

+// have wchar_t available here, but in the GNU C Library

+// wchar_t is always 32 bits wide and wcsncmp uses signed

+// comparison, not unsigned as in strncmp function.

+

+#define WCSNCMP(soname, fnname) \

+   int VG_REPLACE_FUNCTION_EZU(20450,soname,fnname) \

+          ( const Int* s1, const Int* s2, SizeT nmax ); \

+   int VG_REPLACE_FUNCTION_EZU(20450,soname,fnname) \

+          ( const Int* s1, const Int* s2, SizeT nmax ) \

+   { \

+      SizeT n = 0; \

+      while (True) { \

+         if (n >= nmax) return 0; \

+         if (*s1 == 0 && *s2 == 0) return 0; \

+         if (*s1 == 0) return -1; \

+         if (*s2 == 0) return 1; \

+         \

+         if (*s1 < *s2) return -1; \

+         if (*s1 > *s2) return 1; \

+         \

+         s1++; s2++; n++; \

+      } \

+   }

+#if defined(VGO_linux)

+ WCSNCMP(VG_Z_LIBC_SONAME,          wcsncmp)

+#endif

+

 /*---------------------- wcscpy ----------------------*/

 // This is a wchar_t equivalent to strcpy.  We don't