MIPS: Fixing CLANG compilation warnings

src/mips64/cpu-mips64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // CPU specific code for arm independent of OS goes here.
 
 #include <sys/syscall.h>
 #include <unistd.h>
 
 #ifdef __mips
@@ skipping 17 matching lines @@
   if (size == 0) {
     return;
   }
 
 #if defined(ANDROID) && !defined(__LP64__)
   // Bionic cacheflush can typically run in userland, avoiding kernel call.
   char *end = reinterpret_cast<char *>(start) + size;
   cacheflush(
     reinterpret_cast<intptr_t>(start), reinterpret_cast<intptr_t>(end), 0);
 #else  // ANDROID
-  int res;
+  long res;  // NOLINT(runtime/int)

[balazs.kilvady, 2015/12/02 18:49:07]

Do we need long at here? syscall returns with int.

[ivica.bogosavljevic, 2015/12/03 10:36:24]

On MIPS64, if we leave int here than we cannot compile it under CLANG. If we set
long, it compiles both under GCC and CLANG. I executed all the tests and I
didn't see any new failures or something suspicious. 

The specification is ambiguous, I read that syscall can return long (e.g.
http://man7.org/linux/man-pages/man2/syscall.2.html) or int (on my system man
syscall) 

   // See http://www.linux-mips.org/wiki/Cacheflush_Syscall.
   res = syscall(__NR_cacheflush, start, size, ICACHE);
   if (res) {
     V8_Fatal(__FILE__, __LINE__, "Failed to flush the instruction cache");
   }
 #endif  // ANDROID
 #endif  // !USE_SIMULATOR.
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64