src/base/compiler.hh

   1 /*
   2  * Copyright (c) 2012,2017-2018 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Copyright (c) 2006 The Regents of The University of Michigan
  15  * All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions are
  19  * met: redistributions of source code must retain the above copyright
  20  * notice, this list of conditions and the following disclaimer;
  21  * redistributions in binary form must reproduce the above copyright
  22  * notice, this list of conditions and the following disclaimer in the
  23  * documentation and/or other materials provided with the distribution;
  24  * neither the name of the copyright holders nor the names of its
  25  * contributors may be used to endorse or promote products derived from
  26  * this software without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  32  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  33  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  34  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  35  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  36  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  37  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  38  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  39  *
  40  * Authors: Ali Saidi
  41  */
  42
  43 #ifndef __BASE_COMPILER_HH__
  44 #define __BASE_COMPILER_HH__
  45
  46 #include <memory>
  47
  48 // http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
  49
  50 #if defined(__GNUC__) // clang or gcc
  51 #  define M5_ATTR_NORETURN  __attribute__((noreturn))
  52 #  define M5_DUMMY_RETURN
  53 #  define M5_VAR_USED __attribute__((unused))
  54 #  define M5_ATTR_PACKED __attribute__ ((__packed__))
  55 #  define M5_NO_INLINE __attribute__ ((__noinline__))
  56 #  define M5_DEPRECATED __attribute__((deprecated))
  57 #  define M5_DEPRECATED_MSG(MSG) __attribute__((deprecated(MSG)))
  58 #  define M5_UNREACHABLE __builtin_unreachable()
  59 #  define M5_PUBLIC __attribute__ ((visibility ("default")))
  60 #  define M5_LOCAL __attribute__ ((visibility ("hidden")))
  61 #endif
  62
  63 #if defined(__clang__)
  64 #  define M5_CLASS_VAR_USED M5_VAR_USED
  65 #else
  66 #  define M5_CLASS_VAR_USED
  67 #endif
  68
  69 // This can be removed once all compilers support C++17
  70 #if defined __has_cpp_attribute
  71     // Note: We must separate this if statement because GCC < 5.0 doesn't
  72     //       support the function-like syntax in #if statements.
  73     #if __has_cpp_attribute(fallthrough)
  74         #define M5_FALLTHROUGH [[fallthrough]]
  75     #else
  76         #define M5_FALLTHROUGH
  77     #endif
  78
  79     #if __has_cpp_attribute(nodiscard)
  80         #define M5_NODISCARD [[nodiscard]]
  81     #else
  82         #define M5_NODISCARD
  83     #endif
  84 #else
  85     // Unsupported (and no warning) on GCC < 7.
  86     #define M5_FALLTHROUGH
  87
  88     #define M5_NODISCARD
  89 #endif
  90
  91 // std::make_unique redefined for C++11 compilers
  92 namespace m5
  93 {
  94
  95 #if __cplusplus >= 201402L // C++14
  96
  97 using std::make_unique;
  98
  99 #else // C++11
 100
 101 /** Defining custom version of make_unique: m5::make_unique<>() */
 102 template<typename T, typename... Args>
 103 std::unique_ptr<T>
 104 make_unique( Args&&... constructor_args )
 105 {
 106     return std::unique_ptr<T>(
 107                new T( std::forward<Args>(constructor_args)... )
 108            );
 109 }
 110
 111 #endif // __cplusplus >= 201402L
 112
 113 } //namespace m5
 114
 115 #endif // __BASE_COMPILER_HH__