gnu.cfg: Added support for '__builtin_memset'.

cfg/gnu.cfg

@@ -24,6 +24,24 @@
     </arg>
     <leak-ignore/>
   </function>
+  <!-- void *__builtin_memset(void *s, int c, size_t n); -->
+  <function name="__builtin_memset">
+    <returnValue type="void *"/>
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <arg nr="1">
+      <not-null/>
+      <minsize type="argvalue" arg="3"/>
+    </arg>
+    <arg nr="2">
+      <not-uninit/>
+    </arg>
+    <arg nr="3">
+      <not-uninit/>
+      <not-bool/>
+      <valid>0:</valid>
+    </arg>
+  </function>
   <!-- long long atoq(const char *nptr); -->
   <function name="atoq">
     <returnValue type="long long"/>

test/cfg/gnu.c

@@ -8,10 +8,34 @@
 //
 
 #include <string.h>
+#include <stdlib.h>
 #ifndef __CYGWIN__
 #include <sys/epoll.h>
 #endif
 
+void ignoreleak(void)
+{
+    char *p = (char *)malloc(10);
+    __builtin_memset(&(p[0]), 0, 10);
+    // cppcheck-suppress memleak
+}
+
+void uninitvar__builtin_memset(void)
+{
+    void *s;
+    int c;
+    size_t n;
+    // cppcheck-suppress uninitvar
+    (void)__builtin_memset(s,c,n);
+}
+
+void bufferAccessOutOfBounds__builtin_memset(void)
+{
+    uint8_t buf[42];
+    // cppcheck-suppress bufferAccessOutOfBounds
+    (void)__builtin_memset(buf,0,1000);
+}
+
 void bufferAccessOutOfBounds()
 {
     char buf[2];