X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2FPortability.h;h=15f393e0be911d2f8eacb252ddc1bad9a362f07b;hp=8b95c31e64d55b3dea6565a38c19debd7f84f3ab;hb=1bdec475acac176a9692b6e506564c8c0ccd1984;hpb=13f7a671563b4fddc69aa24ba6de4583cf7546ec

diff --git a/folly/Portability.h b/folly/Portability.h
index 8b95c31e..15f393e0 100644
--- a/folly/Portability.h
+++ b/folly/Portability.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 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.
@@ -14,54 +14,92 @@
  * limitations under the License.
  */
 
-#ifndef FOLLY_PORTABILITY_H_
-#define FOLLY_PORTABILITY_H_
-
-// @nocommit invalidate ccache 20151125 (see #8764509)
+#pragma once
 
 #include <string.h>
 
 #include <cstddef>
+#include <type_traits>
 
-#ifndef FOLLY_NO_CONFIG
-#include <folly/folly-config.h>
-#endif
-
-#ifdef FOLLY_PLATFORM_CONFIG
-#include FOLLY_PLATFORM_CONFIG
-#endif
-
-#if FOLLY_HAVE_FEATURES_H
-#include <features.h>
-#endif
+#include <folly/portability/Config.h>
 
 #include <folly/CPortability.h>
 
-#ifdef __APPLE__
-# include <malloc/malloc.h>
-#endif
-
-#if FOLLY_HAVE_SCHED_H
- #include <sched.h>
- #ifndef FOLLY_HAVE_PTHREAD_YIELD
-  #define pthread_yield sched_yield
- #endif
-#endif
-
-#ifndef FOLLY_HAVE_UNALIGNED_READS
-#define FOLLY_HAVE_UNALIGNED_READS 0
-#endif
+// Unaligned loads and stores
+namespace folly {
+#if FOLLY_HAVE_UNALIGNED_ACCESS
+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 {};
 
-// A change in folly/MemoryMapping.cpp uses MAP_ANONYMOUS, which is named
-// MAP_ANON on OSX/BSD.
-#if defined(__APPLE__) || defined(__FreeBSD__)
-  #include <sys/mman.h>
-  #ifndef MAP_ANONYMOUS
-    #ifdef MAP_ANON
-      #define MAP_ANONYMOUS MAP_ANON
-    #endif
-  #endif
-#endif
+} // namespace folly
 
 // compiler specific attribute translation
 // msvc should come first, so if clang is in msvc mode it gets the right defines
@@ -73,7 +111,7 @@
 #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
@@ -82,7 +120,7 @@
 # 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
@@ -100,31 +138,27 @@
 # define FOLLY_DEPRECATED(msg)
 #endif
 
-// noreturn
-#if defined(_MSC_VER)
-# define FOLLY_NORETURN __declspec(noreturn)
-#elif defined(__clang__) || defined(__GNUC__)
-# define FOLLY_NORETURN __attribute__((__noreturn__))
-#else
-# define FOLLY_NORETURN
+// warn unused result
+#if defined(__has_cpp_attribute)
+#if __has_cpp_attribute(nodiscard)
+#define FOLLY_NODISCARD [[nodiscard]]
 #endif
-
-// noinline
-#ifdef _MSC_VER
-# define FOLLY_NOINLINE __declspec(noinline)
+#endif
+#if !defined FOLLY_NODISCARD
+#if defined(_MSC_VER) && (_MSC_VER >= 1700)
+#define FOLLY_NODISCARD _Check_return_
 #elif defined(__clang__) || defined(__GNUC__)
-# define FOLLY_NOINLINE __attribute__((__noinline__))
+#define FOLLY_NODISCARD __attribute__((__warn_unused_result__))
 #else
-# define FOLLY_NOINLINE
+#define FOLLY_NODISCARD
+#endif
 #endif
 
-// always inline
+// target
 #ifdef _MSC_VER
-# define FOLLY_ALWAYS_INLINE __forceinline
-#elif defined(__clang__) || defined(__GNUC__)
-# define FOLLY_ALWAYS_INLINE inline __attribute__((__always_inline__))
+# define FOLLY_TARGET_ATTRIBUTE(target)
 #else
-# define FOLLY_ALWAYS_INLINE inline
+# define FOLLY_TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
 #endif
 
 // detection for 64 bit
@@ -135,9 +169,9 @@
 #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__)
@@ -146,6 +180,27 @@
 # 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
+} // namespace folly
+
 // packing is very ugly in msvc
 #ifdef _MSC_VER
 # define FOLLY_PACK_ATTR /**/
@@ -161,35 +216,35 @@
 # define FOLLY_PACK_POP /**/
 #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; }
+// Generalize warning push/pop.
+#if defined(_MSC_VER)
+# define FOLLY_PUSH_WARNING __pragma(warning(push))
+# define FOLLY_POP_WARNING __pragma(warning(pop))
+// Disable the GCC warnings.
+# define FOLLY_GCC_DISABLE_WARNING(warningName)
+# define FOLLY_MSVC_DISABLE_WARNING(warningNumber) __pragma(warning(disable: warningNumber))
+#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_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
+# define FOLLY_PUSH_WARNING
+# define FOLLY_POP_WARNING
+# define FOLLY_GCC_DISABLE_WARNING(warningName)
+# define FOLLY_MSVC_DISABLE_WARNING(warningNumber)
 #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
@@ -206,21 +261,15 @@ namespace std { typedef ::max_align_t max_align_t; }
 # error cannot define platform specific thread local storage
 #endif
 
-// Define to 1 if you have the `preadv' and `pwritev' functions, respectively
-#if !defined(FOLLY_HAVE_PREADV) && !defined(FOLLY_HAVE_PWRITEV)
-# if defined(__GLIBC_PREREQ)
-#  if __GLIBC_PREREQ(2, 10)
-#   define FOLLY_HAVE_PREADV 1
-#   define FOLLY_HAVE_PWRITEV 1
-#  endif
-# endif
+#if FOLLY_MOBILE
+#undef FOLLY_TLS
 #endif
 
 // It turns out that GNU libstdc++ and LLVM libc++ differ on how they implement
 // 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
@@ -231,65 +280,18 @@ 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
 
-// Some platforms lack clock_gettime(2) and clock_getres(2). Inject our own
-// versions of these into the global namespace.
-#if FOLLY_HAVE_CLOCK_GETTIME
-#include <time.h>
-#else
-#include <folly/detail/Clock.h>
-#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
-
-// this definition is in a really silly place with a silly name
-// and ifdefing it every time we want it is painful
-#include <basetsd.h>
-typedef SSIZE_T ssize_t;
-
-// sprintf semantics are not exactly identical
-// but current usage is not a problem
-# define snprintf _snprintf
-
-// semantics here are identical
-# define strerror_r(errno,buf,len) strerror_s(buf,len,errno)
+#include <folly/portability/SysTypes.h>
 
 // compiler specific to compiler specific
 // nolint
@@ -298,12 +300,20 @@ typedef SSIZE_T ssize_t;
 // Hide a GCC specific thing that breaks MSVC if left alone.
 # define __extension__
 
-#ifdef _M_IX86_FP
-# define FOLLY_SSE _M_IX86_FP
-# define FOLLY_SSE_MINOR 0
+// We have compiler support for the newest of the new, but
+// MSVC doesn't tell us that.
+#define __SSE4_2__ 1
+
 #endif
 
+// Debug
+namespace folly {
+#ifdef NDEBUG
+constexpr auto kIsDebug = false;
+#else
+constexpr auto kIsDebug = true;
 #endif
+} // namespace folly
 
 // Endianness
 namespace folly {
@@ -318,7 +328,7 @@ 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__)
@@ -352,19 +362,12 @@ 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>
-#endif
-
-// MacOS doesn't have malloc_usable_size()
-#if defined(__APPLE__) && !defined(FOLLY_HAVE_MALLOC_USABLE_SIZE)
-inline size_t malloc_usable_size(void* ptr) {
-  return malloc_size(ptr);
-}
+#include <TargetConditionals.h> // @manual
 #endif
 
 // RTTI may not be enabled for this compilation unit.
@@ -373,59 +376,61 @@ inline size_t malloc_usable_size(void* ptr) {
 # define FOLLY_HAS_RTTI 1
 #endif
 
-#ifdef _MSC_VER
-# include <intrin.h>
+#if defined(__APPLE__) || defined(_MSC_VER)
+#define FOLLY_STATIC_CTOR_PRIORITY_MAX
+#else
+// 101 is the highest priority allowed by the init_priority attribute.
+// This priority is already used by JEMalloc and other memory allocators so
+// we will take the next one.
+#define FOLLY_STATIC_CTOR_PRIORITY_MAX __attribute__((__init_priority__(102)))
 #endif
 
 namespace folly {
 
-inline void asm_volatile_memory() {
-#if defined(__clang__) || defined(__GNUC__)
-  asm volatile("" : : : "memory");
-#elif defined(_MSC_VER)
-  ::_ReadWriteBarrier();
-#endif
-}
-
-inline void asm_volatile_pause() {
-#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
-  ::_mm_pause();
-#elif defined(__i386__) || FOLLY_X64
-  asm volatile ("pause");
-#elif FOLLY_A64
-  asm volatile ("wfe");
-#elif FOLLY_PPC64
-  asm volatile("or 27,27,27");
-#endif
-}
-inline void asm_pause() {
-#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
-  ::_mm_pause();
-#elif defined(__i386__) || FOLLY_X64
-  asm ("pause");
-#elif FOLLY_A64
-  asm ("wfe");
-#elif FOLLY_PPC64
-  asm ("or 31,31,31");
-#endif
-}
-
-constexpr size_t constexpr_strlen(const char* s) {
-#if defined(__clang__)
-  return __builtin_strlen(s);
+#if __OBJC__
+constexpr auto kIsObjC = true;
 #else
-  return strlen(s);
+constexpr auto kIsObjC = false;
 #endif
-}
 
-#if defined(__APPLE__) || defined(_MSC_VER)
-#define MAX_STATIC_CONSTRUCTOR_PRIORITY
+#if defined(__linux__) && !FOLLY_MOBILE
+constexpr auto kIsLinux = true;
 #else
-// 101 is the highest priority allowed by the init_priority attribute.
-// This priority is already used by JEMalloc and other memory allocators so
-// we will take the next one.
-#define MAX_STATIC_CONSTRUCTOR_PRIORITY __attribute__ ((__init_priority__(102)))
+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
-#endif // FOLLY_PORTABILITY_H_
+
+// 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