hphp/util/arch.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #pragma once
  18
  19 #include "hphp/util/assertions.h"
  20
  21 namespace HPHP {
  22 ///////////////////////////////////////////////////////////////////////////////
  23
  24 enum class Arch { X64, ARM, };
  25
  26 constexpr Arch arch() {
  27 #if defined(__aarch64__)
  28   return Arch::ARM;
  29 #else
  30   return Arch::X64;
  31 #endif
  32 }
  33
  34 constexpr bool arch_any() { return false; }
  35
  36 /*
  37  * Convenience helper for guarding on a set of architectures.
  38  */
  39 template<class... Tail>
  40 bool arch_any(Arch a, Tail&&... archs) {
  41   return arch() == a || arch_any(archs...);
  42 }
  43
  44 /*
  45  * MSVC's Preprocessor is completely idiotic, so we have to play by its rules
  46  * and forcefully expand the variadic args so they aren't all interpreted as the
  47  * first argument to func.
  48  */
  49 #define MSVC_GLUE(x, y) x y
  50
  51 /*
  52  * Macro for defining easy arch-dispatch wrappers.
  53  *
  54  * We need to specify the return type explicitly, or else we may drop refs.
  55  */
  56 #define ARCH_SWITCH_CALL(func, ...)                                   \
  57   ([&]() -> decltype(x64::func(__VA_ARGS__)) {                        \
  58     switch (arch()) {                                                 \
  59       case Arch::X64:                                                 \
  60         return x64::MSVC_GLUE(func, (__VA_ARGS__));                   \
  61       case Arch::ARM:                                                 \
  62         return arm::MSVC_GLUE(func, (__VA_ARGS__));                   \
  63     }                                                                 \
  64     not_reached();                                                    \
  65   }())
  66
  67 ///////////////////////////////////////////////////////////////////////////////
  68
  69 }
  70