X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2FPortability.h;h=6c140379de9e9920755e3eb70cb615c6bd8acb88;hp=56dc7c95c2a59c1994f2cde035518a1f512c8374;hb=614eb71734a284e1a9fefabcc48743a3c8efd653;hpb=ad2f228ab1359952d37acdc4f3032e1405cca221

diff --git a/folly/Portability.h b/folly/Portability.h
index 56dc7c95..6c140379 100644
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,15 +19,12 @@
 #include <string.h>
 
 #include <cstddef>
+#include <type_traits>
 
 #include <folly/portability/Config.h>
 
 #include <folly/CPortability.h>
 
-#if FOLLY_HAVE_SCHED_H
- #include <sched.h>
-#endif
-
 // Unaligned loads and stores
 namespace folly {
 #if FOLLY_HAVE_UNALIGNED_ACCESS
@@ -35,7 +32,74 @@ constexpr bool kHasUnalignedAccess = true;
 #else
 constexpr bool kHasUnalignedAccess = false;
 #endif
-}
+
+namespace portability_detail {
+
+template <typename I, I A, I B>
+using integral_max = std::integral_constant<I, (A < B) ? B : A>;
+
+template <typename I, I A, I... Bs>
+struct integral_sequence_max
+    : integral_max<I, A, integral_sequence_max<I, Bs...>::value> {};
+
+template <typename I, I A>
+struct integral_sequence_max<I, A> : std::integral_constant<I, A> {};
+
+template <typename... Ts>
+using max_alignment = integral_sequence_max<size_t, alignof(Ts)...>;
+
+using max_basic_alignment = max_alignment<
+    std::max_align_t,
+    long double,
+    double,
+    float,
+    long long int,
+    long int,
+    int,
+    short int,
+    bool,
+    char,
+    char16_t,
+    char32_t,
+    wchar_t,
+    std::nullptr_t>;
+} // namespace portability_detail
+
+constexpr size_t max_align_v = portability_detail::max_basic_alignment::value;
+
+// max_align_t is a type which is aligned at least as strictly as the
+// most-aligned basic type (see the specification of std::max_align_t). This
+// implementation exists because 32-bit iOS platforms have a broken
+// std::max_align_t (see below).
+//
+// You should refer to this as `::folly::max_align_t` in portable code, even if
+// you have `using namespace folly;` because C11 defines a global namespace
+// `max_align_t` type.
+//
+// To be certain, we consider every non-void fundamental type specified by the
+// standard. On most platforms `long double` would be enough, but iOS 32-bit
+// has an 8-byte aligned `double` and `long long int` and a 4-byte aligned
+// `long double`.
+//
+// So far we've covered locals and other non-allocated storage, but we also need
+// confidence that allocated storage from `malloc`, `new`, etc will also be
+// suitable for objects with this alignment reuirement.
+//
+// Apple document that their implementation of malloc will issue 16-byte
+// granularity chunks for small allocations (large allocations are page-size
+// granularity and page-aligned). We think that allocated storage will be
+// suitable for these objects based on the following assumptions:
+//
+// 1. 16-byte granularity also means 16-byte aligned.
+// 2. `new` and other allocators follow the `malloc` rules.
+//
+// We also have some anecdotal evidence: we don't see lots of misaligned-storage
+// crashes on 32-bit iOS apps that use `double`.
+//
+// Apple's allocation reference: http://bit.ly/malloc-small
+struct alignas(max_align_v) max_align_t {};
+
+} // namespace folly
 
 // compiler specific attribute translation
 // msvc should come first, so if clang is in msvc mode it gets the right defines
@@ -47,7 +111,7 @@ constexpr bool kHasUnalignedAccess = false;
 #else
 # error Cannot define FOLLY_ALIGNED on this platform
 #endif
-#define FOLLY_ALIGNED_MAX FOLLY_ALIGNED(alignof(std::max_align_t))
+#define FOLLY_ALIGNED_MAX FOLLY_ALIGNED(::folly::max_align_v)
 
 // NOTE: this will only do checking in msvc with versions that support /analyze
 #if _MSC_VER
@@ -56,7 +120,7 @@ constexpr bool kHasUnalignedAccess = false;
 # endif
 /* nolint */
 # define _USE_ATTRIBUTES_FOR_SAL 1
-# include <sal.h>
+# include <sal.h> // @manual
 # define FOLLY_PRINTF_FORMAT _Printf_format_string_
 # define FOLLY_PRINTF_FORMAT_ATTR(format_param, dots_param) /**/
 #else
@@ -74,22 +138,20 @@ constexpr bool kHasUnalignedAccess = false;
 # define FOLLY_DEPRECATED(msg)
 #endif
 
-// noinline
-#ifdef _MSC_VER
-# define FOLLY_NOINLINE __declspec(noinline)
-#elif defined(__clang__) || defined(__GNUC__)
-# define FOLLY_NOINLINE __attribute__((__noinline__))
-#else
-# define FOLLY_NOINLINE
+// warn unused result
+#if defined(__has_cpp_attribute)
+#if __has_cpp_attribute(nodiscard)
+#define FOLLY_NODISCARD [[nodiscard]]
 #endif
-
-// always inline
-#ifdef _MSC_VER
-# define FOLLY_ALWAYS_INLINE __forceinline
+#endif
+#if !defined FOLLY_NODISCARD
+#if defined(_MSC_VER) && (_MSC_VER >= 1700)
+#define FOLLY_NODISCARD _Check_return_
 #elif defined(__clang__) || defined(__GNUC__)
-# define FOLLY_ALWAYS_INLINE inline __attribute__((__always_inline__))
+#define FOLLY_NODISCARD __attribute__((__warn_unused_result__))
 #else
-# define FOLLY_ALWAYS_INLINE inline
+#define FOLLY_NODISCARD
+#endif
 #endif
 
 // target
@@ -107,9 +169,9 @@ constexpr bool kHasUnalignedAccess = false;
 #endif
 
 #if defined(__aarch64__)
-# define FOLLY_A64 1
+# define FOLLY_AARCH64 1
 #else
-# define FOLLY_A64 0
+# define FOLLY_AARCH64 0
 #endif
 
 #if defined (__powerpc64__)
@@ -118,6 +180,33 @@ constexpr bool kHasUnalignedAccess = false;
 # define FOLLY_PPC64 0
 #endif
 
+namespace folly {
+constexpr bool kIsArchAmd64 = FOLLY_X64 == 1;
+constexpr bool kIsArchAArch64 = FOLLY_AARCH64 == 1;
+constexpr bool kIsArchPPC64 = FOLLY_PPC64 == 1;
+} // namespace folly
+
+namespace folly {
+
+#if FOLLY_SANITIZE_ADDRESS
+constexpr bool kIsSanitizeAddress = true;
+#else
+constexpr bool kIsSanitizeAddress = false;
+#endif
+
+#if FOLLY_SANITIZE_THREAD
+constexpr bool kIsSanitizeThread = true;
+#else
+constexpr bool kIsSanitizeThread = false;
+#endif
+
+#if FOLLY_SANITIZE
+constexpr bool kIsSanitize = true;
+#else
+constexpr bool kIsSanitize = false;
+#endif
+} // namespace folly
+
 // packing is very ugly in msvc
 #ifdef _MSC_VER
 # define FOLLY_PACK_ATTR /**/
@@ -143,12 +232,10 @@ constexpr bool kHasUnalignedAccess = false;
 #elif defined(__clang__) || defined(__GNUC__)
 # define FOLLY_PUSH_WARNING _Pragma("GCC diagnostic push")
 # define FOLLY_POP_WARNING _Pragma("GCC diagnostic pop")
-#define FOLLY_GCC_DISABLE_WARNING_INTERNAL3(warningName) #warningName
-#define FOLLY_GCC_DISABLE_WARNING_INTERNAL2(warningName) \
-  FOLLY_GCC_DISABLE_WARNING_INTERNAL3(warningName)
-#define FOLLY_GCC_DISABLE_WARNING(warningName)                       \
-  _Pragma(FOLLY_GCC_DISABLE_WARNING_INTERNAL2(GCC diagnostic ignored \
-          FOLLY_GCC_DISABLE_WARNING_INTERNAL3(-W##warningName)))
+# define FOLLY_GCC_DISABLE_WARNING_INTERNAL2(warningName) #warningName
+# define FOLLY_GCC_DISABLE_WARNING(warningName) \
+  _Pragma(                                      \
+  FOLLY_GCC_DISABLE_WARNING_INTERNAL2(GCC diagnostic ignored warningName))
 // Disable the MSVC warnings.
 # define FOLLY_MSVC_DISABLE_WARNING(warningNumber)
 #else
@@ -158,35 +245,12 @@ constexpr bool kHasUnalignedAccess = false;
 # define FOLLY_MSVC_DISABLE_WARNING(warningNumber)
 #endif
 
-// portable version check
-#ifndef __GNUC_PREREQ
-# if defined __GNUC__ && defined __GNUC_MINOR__
-/* nolint */
-#  define __GNUC_PREREQ(maj, min) ((__GNUC__ << 16) + __GNUC_MINOR__ >= \
-                                   ((maj) << 16) + (min))
-# else
-/* nolint */
-#  define __GNUC_PREREQ(maj, min) 0
-# endif
-#endif
-
-#if defined(__GNUC__) && !defined(__APPLE__) && !__GNUC_PREREQ(4,9)
-// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56019
-// gcc 4.8.x incorrectly placed max_align_t in the root namespace
-// Alias it into std (where it's found in 4.9 and later)
-namespace std { typedef ::max_align_t max_align_t; }
-#endif
-
-// portable version check for clang
-#ifndef __CLANG_PREREQ
-# if defined __clang__ && defined __clang_major__ && defined __clang_minor__
-/* nolint */
-#  define __CLANG_PREREQ(maj, min) \
-    ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min))
-# else
-/* nolint */
-#  define __CLANG_PREREQ(maj, min) 0
-# endif
+#ifdef FOLLY_HAVE_SHADOW_LOCAL_WARNINGS
+#define FOLLY_GCC_DISABLE_NEW_SHADOW_WARNINGS        \
+  FOLLY_GCC_DISABLE_WARNING("-Wshadow-compatible-local") \
+  FOLLY_GCC_DISABLE_WARNING("-Wshadow-local")
+#else
+#define FOLLY_GCC_DISABLE_NEW_SHADOW_WARNINGS /* empty */
 #endif
 
 /* Platform specific TLS support
@@ -211,7 +275,7 @@ namespace std { typedef ::max_align_t max_align_t; }
 // the 'std' namespace; the latter uses inline namespaces. Wrap this decision
 // up in a macro to make forward-declarations easier.
 #if FOLLY_USE_LIBCPP
-#include <__config>
+#include <__config> // @manual
 #define FOLLY_NAMESPACE_STD_BEGIN     _LIBCPP_BEGIN_NAMESPACE_STD
 #define FOLLY_NAMESPACE_STD_END       _LIBCPP_END_NAMESPACE_STD
 #else
@@ -222,42 +286,14 @@ namespace std { typedef ::max_align_t max_align_t; }
 // If the new c++ ABI is used, __cxx11 inline namespace needs to be added to
 // some types, e.g. std::list.
 #if _GLIBCXX_USE_CXX11_ABI
-# define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN _GLIBCXX_BEGIN_NAMESPACE_CXX11
+#define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN \
+  inline _GLIBCXX_BEGIN_NAMESPACE_CXX11
 # define FOLLY_GLIBCXX_NAMESPACE_CXX11_END   _GLIBCXX_END_NAMESPACE_CXX11
 #else
 # define FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
 # define FOLLY_GLIBCXX_NAMESPACE_CXX11_END
 #endif
 
-// Provide our own std::__throw_* wrappers for platforms that don't have them
-#if FOLLY_HAVE_BITS_FUNCTEXCEPT_H
-#include <bits/functexcept.h>
-#else
-#include <folly/detail/FunctionalExcept.h>
-#endif
-
-#if defined(__cplusplus)
-// Unfortunately, boost::has_trivial_copy<T> is broken in libc++ due to its
-// usage of __has_trivial_copy(), so we can't use it as a
-// least-common-denominator for C++11 implementations that don't support
-// std::is_trivially_copyable<T>.
-//
-//      http://stackoverflow.com/questions/12754886/has-trivial-copy-behaves-differently-in-clang-and-gcc-whos-right
-//
-// As a result, use std::is_trivially_copyable() where it exists, and fall back
-// to Boost otherwise.
-#if FOLLY_HAVE_STD__IS_TRIVIALLY_COPYABLE
-#include <type_traits>
-#define FOLLY_IS_TRIVIALLY_COPYABLE(T)                   \
-  (std::is_trivially_copyable<T>::value)
-#else
-#include <boost/type_traits.hpp>
-#define FOLLY_IS_TRIVIALLY_COPYABLE(T)                   \
-  (boost::has_trivial_copy<T>::value &&                  \
-   boost::has_trivial_destructor<T>::value)
-#endif
-#endif // __cplusplus
-
 // MSVC specific defines
 // mainly for posix compat
 #ifdef _MSC_VER
@@ -283,7 +319,7 @@ constexpr auto kIsDebug = false;
 #else
 constexpr auto kIsDebug = true;
 #endif
-}
+} // namespace folly
 
 // Endianness
 namespace folly {
@@ -298,7 +334,7 @@ constexpr auto kIsLittleEndian = true;
 constexpr auto kIsLittleEndian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__;
 #endif
 constexpr auto kIsBigEndian = !kIsLittleEndian;
-}
+} // namespace folly
 
 #ifndef FOLLY_SSE
 # if defined(__SSE4_2__)
@@ -332,12 +368,12 @@ constexpr auto kIsBigEndian = !kIsLittleEndian;
 namespace FOLLY_GFLAGS_NAMESPACE { }
 namespace gflags {
 using namespace FOLLY_GFLAGS_NAMESPACE;
-}  // namespace gflags
+} // namespace gflags
 #endif
 
 // for TARGET_OS_IPHONE
 #ifdef __APPLE__
-#include <TargetConditionals.h>
+#include <TargetConditionals.h> // @manual
 #endif
 
 // RTTI may not be enabled for this compilation unit.
@@ -357,9 +393,50 @@ using namespace FOLLY_GFLAGS_NAMESPACE;
 
 namespace folly {
 
+#if __OBJC__
+constexpr auto kIsObjC = true;
+#else
+constexpr auto kIsObjC = false;
+#endif
+
 #if defined(__linux__) && !FOLLY_MOBILE
 constexpr auto kIsLinux = true;
 #else
 constexpr auto kIsLinux = false;
 #endif
-}
+
+#if defined(_WIN32)
+constexpr auto kIsWindows = true;
+constexpr auto kMscVer = _MSC_VER;
+#else
+constexpr auto kIsWindows = false;
+constexpr auto kMscVer = 0;
+#endif
+} // namespace folly
+
+// Define FOLLY_USE_CPP14_CONSTEXPR to be true if the compiler's C++14
+// constexpr support is "good enough".
+#ifndef FOLLY_USE_CPP14_CONSTEXPR
+#if defined(__clang__)
+#define FOLLY_USE_CPP14_CONSTEXPR __cplusplus >= 201300L
+#elif defined(__GNUC__)
+#define FOLLY_USE_CPP14_CONSTEXPR __cplusplus >= 201304L
+#else
+#define FOLLY_USE_CPP14_CONSTEXPR 0 // MSVC?
+#endif
+#endif
+
+#if FOLLY_USE_CPP14_CONSTEXPR
+#define FOLLY_CPP14_CONSTEXPR constexpr
+#else
+#define FOLLY_CPP14_CONSTEXPR inline
+#endif
+
+#if __cpp_coroutines >= 201703L || (_MSC_VER && _RESUMABLE_FUNCTIONS_SUPPORTED)
+#define FOLLY_HAS_COROUTINES 1
+#endif
+
+// MSVC 2017.5
+#if __cpp_noexcept_function_type >= 201510 || _MSC_FULL_VER >= 191225816
+#define FOLLY_HAVE_NOEXCEPT_FUNCTION_TYPE 1
+#endif