ntdll: Implement NtFlushInstructionCache using __clear_cache where available.

configure

@@ -17759,6 +17759,39 @@ $as_echo "#define HAVE___BUILTIN_POPCOUNT 1" >>confdefs.h
 
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __clear_cache" >&5
+$as_echo_n "checking for __clear_cache... " >&6; }
+if ${ac_cv_have___clear_cache+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+__clear_cache((void*)0, (void*)0); return 0;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_have___clear_cache="yes"
+else
+  ac_cv_have___clear_cache="no"
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_have___clear_cache" >&5
+$as_echo "$ac_cv_have___clear_cache" >&6; }
+if test "$ac_cv_have___clear_cache" = "yes"
+then
+
+$as_echo "#define HAVE___CLEAR_CACHE 1" >>confdefs.h
+
+fi
+
 
 case $host_cpu in
   *i[3456789]86*) { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we need to define __i386__" >&5

configure.ac

@@ -2706,6 +2706,14 @@ then
     AC_DEFINE(HAVE___BUILTIN_POPCOUNT, 1, [Define to 1 if you have the `__builtin_popcount' built-in function.])
 fi
 
+AC_CACHE_CHECK([for __clear_cache], ac_cv_have___clear_cache,
+               AC_LINK_IFELSE([AC_LANG_PROGRAM(,[[__clear_cache((void*)0, (void*)0); return 0;]])],
+               [ac_cv_have___clear_cache="yes"], [ac_cv_have___clear_cache="no"]))
+if test "$ac_cv_have___clear_cache" = "yes"
+then
+    AC_DEFINE(HAVE___CLEAR_CACHE, 1, [Define to 1 if you have the `__clear_cache' (potentially built-in) function.])
+fi
+
 dnl *** check for the need to define platform-specific symbols
 
 case $host_cpu in

dlls/ntdll/process.c

@@ -653,20 +653,24 @@ NTSTATUS WINAPI NtSetInformationProcess(
  * NtFlushInstructionCache [NTDLL.@]
  * ZwFlushInstructionCache [NTDLL.@]
  */
-NTSTATUS WINAPI NtFlushInstructionCache(
-        IN HANDLE ProcessHandle,
-        IN LPCVOID BaseAddress,
-        IN SIZE_T Size)
+NTSTATUS WINAPI NtFlushInstructionCache( HANDLE handle, const void *addr, SIZE_T size )
 {
-    static int once;
-    if (!once++)
-    {
 #if defined(__x86_64__) || defined(__i386__)
-        TRACE("%p %p %ld - no-op on x86 and x86_64\n", ProcessHandle, BaseAddress, Size );
+    /* no-op */
+#elif defined(HAVE___CLEAR_CACHE)
+    if (handle == GetCurrentProcess())
+    {
+        __clear_cache( (char *)addr, (char *)addr + size );
+    }
+    else
+    {
+        static int once;
+        if (!once++) FIXME( "%p %p %ld other process not supported\n", handle, addr, size );
+    }
 #else
-        FIXME("%p %p %ld\n", ProcessHandle, BaseAddress, Size );
+    static int once;
+    if (!once++) FIXME( "%p %p %ld\n", handle, addr, size );
 #endif
-    }
     return STATUS_SUCCESS;
 }
 

include/config.h.in

@@ -1407,6 +1407,10 @@
 /* Define to 1 if you have the `__builtin_popcount' built-in function. */
 #undef HAVE___BUILTIN_POPCOUNT
 
+/* Define to 1 if you have the `__clear_cache' (potentially built-in)
+   function. */
+#undef HAVE___CLEAR_CACHE
+
 /* Define to 1 if you have the `__res_getservers' function. */
 #undef HAVE___RES_GETSERVERS