only define ARRAYSIZE_UNSAFE for NaCl builds

src/base/macros.h

 // Copyright 2014 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.
 
 #ifndef V8_BASE_MACROS_H_
 #define V8_BASE_MACROS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <cstring>
 
 #include "src/base/build_config.h"
 #include "src/base/compiler-specific.h"
 #include "src/base/logging.h"
 
 
 // The expression OFFSET_OF(type, field) computes the byte-offset
 // of the specified field relative to the containing type. This
 // corresponds to 'offsetof' (in stddef.h), except that it doesn't
 // use 0 or NULL, which causes a problem with the compiler warnings
 // we have enabled (which is also why 'offsetof' doesn't seem to work).
 // Here we simply use the non-zero value 4, which seems to work.
 #define OFFSET_OF(type, field)                                          \
   (reinterpret_cast<intptr_t>(&(reinterpret_cast<type*>(4)->field)) - 4)
 
 
+#if V8_OS_NACL
+
 // ARRAYSIZE_UNSAFE performs essentially the same calculation as arraysize,
 // but can be used on anonymous types or types defined inside
 // functions.  It's less safe than arraysize as it accepts some
 // (although not all) pointers.  Therefore, you should use arraysize
 // whenever possible.
 //
 // The expression ARRAYSIZE_UNSAFE(a) is a compile-time constant of type
 // size_t.
 //
 // ARRAYSIZE_UNSAFE catches a few type errors.  If you see a compiler error
@@ skipping 20 matching lines @@
 //
 // This macro is not perfect as it wrongfully accepts certain
 // pointers, namely where the pointer size is divisible by the pointee
 // size.  Since all our code has to go through a 32-bit compiler,
 // where a pointer is 4 bytes, this means all pointers to a type whose
 // size is 3 or greater than 4 will be (righteously) rejected.
 #define ARRAYSIZE_UNSAFE(a)     \
   ((sizeof(a) / sizeof(*(a))) / \
    static_cast<size_t>(!(sizeof(a) % sizeof(*(a)))))  // NOLINT
 
-
-#if V8_OS_NACL
-
 // TODO(bmeurer): For some reason, the NaCl toolchain cannot handle the correct
 // definition of arraysize() below, so we have to use the unsafe version for
 // now.
 #define arraysize ARRAYSIZE_UNSAFE
 
 #else  // V8_OS_NACL
 
 // The arraysize(arr) macro returns the # of elements in an array arr.
 // The expression is a compile-time constant, and therefore can be
 // used in defining new arrays, for example.  If you use arraysize on
@@ skipping 311 matching lines @@
 }
 
 
 // Return the smallest multiple of m which is >= x.
 template <typename T>
 inline T RoundUp(T x, intptr_t m) {
   return RoundDown<T>(static_cast<T>(x + m - 1), m);
 }
 
 #endif   // V8_BASE_MACROS_H_