v8/include/v8config.h
Santiago Aboy Solanes 03a940ebee [config] Add [[nodiscard]] as an attribute to v8config
This allows us to assert at compile time that a class instance is
assigned, which is particularly useful for Guard classes.

Change-Id: Id16b2bb70d29573566e821c908c1169d49ec57af
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2552415
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71397}
2020-11-25 11:49:05 +00:00

514 lines
16 KiB
C

// Copyright 2013 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 V8CONFIG_H_
#define V8CONFIG_H_
// clang-format off
// Platform headers for feature detection below.
#if defined(__ANDROID__)
# include <sys/cdefs.h>
#elif defined(__APPLE__)
# include <TargetConditionals.h>
#elif defined(__linux__)
# include <features.h>
#endif
// This macro allows to test for the version of the GNU C library (or
// a compatible C library that masquerades as glibc). It evaluates to
// 0 if libc is not GNU libc or compatible.
// Use like:
// #if V8_GLIBC_PREREQ(2, 3)
// ...
// #endif
#if defined(__GLIBC__) && defined(__GLIBC_MINOR__)
# define V8_GLIBC_PREREQ(major, minor) \
((__GLIBC__ * 100 + __GLIBC_MINOR__) >= ((major) * 100 + (minor)))
#else
# define V8_GLIBC_PREREQ(major, minor) 0
#endif
// This macro allows to test for the version of the GNU C++ compiler.
// Note that this also applies to compilers that masquerade as GCC,
// for example clang and the Intel C++ compiler for Linux.
// Use like:
// #if V8_GNUC_PREREQ(4, 3, 1)
// ...
// #endif
#if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
# define V8_GNUC_PREREQ(major, minor, patchlevel) \
((__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) >= \
((major) * 10000 + (minor) * 100 + (patchlevel)))
#elif defined(__GNUC__) && defined(__GNUC_MINOR__)
# define V8_GNUC_PREREQ(major, minor, patchlevel) \
((__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= \
((major) * 10000 + (minor) * 100 + (patchlevel)))
#else
# define V8_GNUC_PREREQ(major, minor, patchlevel) 0
#endif
// -----------------------------------------------------------------------------
// Operating system detection (host)
//
// V8_OS_ANDROID - Android
// V8_OS_BSD - BSDish (Mac OS X, Net/Free/Open/DragonFlyBSD)
// V8_OS_CYGWIN - Cygwin
// V8_OS_DRAGONFLYBSD - DragonFlyBSD
// V8_OS_FREEBSD - FreeBSD
// V8_OS_FUCHSIA - Fuchsia
// V8_OS_LINUX - Linux
// V8_OS_MACOSX - Mac OS X
// V8_OS_IOS - iOS
// V8_OS_NETBSD - NetBSD
// V8_OS_OPENBSD - OpenBSD
// V8_OS_POSIX - POSIX compatible (mostly everything except Windows)
// V8_OS_QNX - QNX Neutrino
// V8_OS_SOLARIS - Sun Solaris and OpenSolaris
// V8_OS_STARBOARD - Starboard (platform abstraction for Cobalt)
// V8_OS_AIX - AIX
// V8_OS_WIN - Microsoft Windows
#if defined(__ANDROID__)
# define V8_OS_ANDROID 1
# define V8_OS_LINUX 1
# define V8_OS_POSIX 1
#elif defined(__APPLE__)
# define V8_OS_BSD 1
# define V8_OS_MACOSX 1
# define V8_OS_POSIX 1
# if defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
# define V8_OS_IOS 1
# endif // defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
#elif defined(__CYGWIN__)
# define V8_OS_CYGWIN 1
# define V8_OS_POSIX 1
#elif defined(__linux__)
# define V8_OS_LINUX 1
# define V8_OS_POSIX 1
#elif defined(__sun)
# define V8_OS_POSIX 1
# define V8_OS_SOLARIS 1
#elif defined(STARBOARD)
# define V8_OS_STARBOARD 1
#elif defined(_AIX)
#define V8_OS_POSIX 1
#define V8_OS_AIX 1
#elif defined(__FreeBSD__)
# define V8_OS_BSD 1
# define V8_OS_FREEBSD 1
# define V8_OS_POSIX 1
#elif defined(__Fuchsia__)
# define V8_OS_FUCHSIA 1
# define V8_OS_POSIX 1
#elif defined(__DragonFly__)
# define V8_OS_BSD 1
# define V8_OS_DRAGONFLYBSD 1
# define V8_OS_POSIX 1
#elif defined(__NetBSD__)
# define V8_OS_BSD 1
# define V8_OS_NETBSD 1
# define V8_OS_POSIX 1
#elif defined(__OpenBSD__)
# define V8_OS_BSD 1
# define V8_OS_OPENBSD 1
# define V8_OS_POSIX 1
#elif defined(__QNXNTO__)
# define V8_OS_POSIX 1
# define V8_OS_QNX 1
#elif defined(_WIN32)
# define V8_OS_WIN 1
#endif
// -----------------------------------------------------------------------------
// Operating system detection (target)
//
// V8_TARGET_OS_ANDROID
// V8_TARGET_OS_FUCHSIA
// V8_TARGET_OS_IOS
// V8_TARGET_OS_LINUX
// V8_TARGET_OS_MACOSX
// V8_TARGET_OS_WIN
//
// If not set explicitly, these fall back to corresponding V8_OS_ values.
#ifdef V8_HAVE_TARGET_OS
// The target OS is provided, just check that at least one known value is set.
# if !defined(V8_TARGET_OS_ANDROID) \
&& !defined(V8_TARGET_OS_FUCHSIA) \
&& !defined(V8_TARGET_OS_IOS) \
&& !defined(V8_TARGET_OS_LINUX) \
&& !defined(V8_TARGET_OS_MACOSX) \
&& !defined(V8_TARGET_OS_WIN)
# error No known target OS defined.
# endif
#else // V8_HAVE_TARGET_OS
# if defined(V8_TARGET_OS_ANDROID) \
|| defined(V8_TARGET_OS_FUCHSIA) \
|| defined(V8_TARGET_OS_IOS) \
|| defined(V8_TARGET_OS_LINUX) \
|| defined(V8_TARGET_OS_MACOSX) \
|| defined(V8_TARGET_OS_WIN)
# error A target OS is defined but V8_HAVE_TARGET_OS is unset.
# endif
// Fall back to the detected host OS.
#ifdef V8_OS_ANDROID
# define V8_TARGET_OS_ANDROID
#endif
#ifdef V8_OS_FUCHSIA
# define V8_TARGET_OS_FUCHSIA
#endif
#ifdef V8_OS_IOS
# define V8_TARGET_OS_IOS
#endif
#ifdef V8_OS_LINUX
# define V8_TARGET_OS_LINUX
#endif
#ifdef V8_OS_MACOSX
# define V8_TARGET_OS_MACOSX
#endif
#ifdef V8_OS_WIN
# define V8_TARGET_OS_WIN
#endif
#endif // V8_HAVE_TARGET_OS
// -----------------------------------------------------------------------------
// C library detection
//
// V8_LIBC_MSVCRT - MSVC libc
// V8_LIBC_BIONIC - Bionic libc
// V8_LIBC_BSD - BSD libc derivate
// V8_LIBC_GLIBC - GNU C library
// V8_LIBC_UCLIBC - uClibc
//
// Note that testing for libc must be done using #if not #ifdef. For example,
// to test for the GNU C library, use:
// #if V8_LIBC_GLIBC
// ...
// #endif
#if defined (_MSC_VER)
# define V8_LIBC_MSVCRT 1
#elif defined(__BIONIC__)
# define V8_LIBC_BIONIC 1
# define V8_LIBC_BSD 1
#elif defined(__UCLIBC__)
// Must test for UCLIBC before GLIBC, as UCLIBC pretends to be GLIBC.
# define V8_LIBC_UCLIBC 1
#elif defined(__GLIBC__) || defined(__GNU_LIBRARY__)
# define V8_LIBC_GLIBC 1
#else
# define V8_LIBC_BSD V8_OS_BSD
#endif
// -----------------------------------------------------------------------------
// Compiler detection
//
// V8_CC_GNU - GCC, or clang in gcc mode
// V8_CC_INTEL - Intel C++
// V8_CC_MINGW - Minimalist GNU for Windows
// V8_CC_MINGW32 - Minimalist GNU for Windows (mingw32)
// V8_CC_MINGW64 - Minimalist GNU for Windows (mingw-w64)
// V8_CC_MSVC - Microsoft Visual C/C++, or clang in cl.exe mode
//
// C++11 feature detection
//
// Compiler-specific feature detection
//
// V8_HAS_ATTRIBUTE_ALWAYS_INLINE - __attribute__((always_inline))
// supported
// V8_HAS_ATTRIBUTE_NONNULL - __attribute__((nonnull)) supported
// V8_HAS_ATTRIBUTE_NOINLINE - __attribute__((noinline)) supported
// V8_HAS_ATTRIBUTE_UNUSED - __attribute__((unused)) supported
// V8_HAS_ATTRIBUTE_VISIBILITY - __attribute__((visibility)) supported
// V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT - __attribute__((warn_unused_result))
// supported
// V8_HAS_CPP_ATTRIBUTE_NODISCARD - [[nodiscard]] supported
// V8_HAS_BUILTIN_BSWAP16 - __builtin_bswap16() supported
// V8_HAS_BUILTIN_BSWAP32 - __builtin_bswap32() supported
// V8_HAS_BUILTIN_BSWAP64 - __builtin_bswap64() supported
// V8_HAS_BUILTIN_CLZ - __builtin_clz() supported
// V8_HAS_BUILTIN_CTZ - __builtin_ctz() supported
// V8_HAS_BUILTIN_EXPECT - __builtin_expect() supported
// V8_HAS_BUILTIN_FRAME_ADDRESS - __builtin_frame_address() supported
// V8_HAS_BUILTIN_POPCOUNT - __builtin_popcount() supported
// V8_HAS_BUILTIN_SADD_OVERFLOW - __builtin_sadd_overflow() supported
// V8_HAS_BUILTIN_SSUB_OVERFLOW - __builtin_ssub_overflow() supported
// V8_HAS_BUILTIN_UADD_OVERFLOW - __builtin_uadd_overflow() supported
// V8_HAS_COMPUTED_GOTO - computed goto/labels as values
// supported
// V8_HAS_DECLSPEC_NOINLINE - __declspec(noinline) supported
// V8_HAS_DECLSPEC_SELECTANY - __declspec(selectany) supported
// V8_HAS___FORCEINLINE - __forceinline supported
//
// Note that testing for compilers and/or features must be done using #if
// not #ifdef. For example, to test for Intel C++ Compiler, use:
// #if V8_CC_INTEL
// ...
// #endif
#if defined(__has_cpp_attribute)
#define V8_HAS_CPP_ATTRIBUTE(FEATURE) __has_cpp_attribute(FEATURE)
#else
#define V8_HAS_CPP_ATTRIBUTE(FEATURE) 0
#endif
#if defined(__clang__)
#if defined(__GNUC__) // Clang in gcc mode.
# define V8_CC_GNU 1
#endif
# define V8_HAS_ATTRIBUTE_ALWAYS_INLINE (__has_attribute(always_inline))
# define V8_HAS_ATTRIBUTE_NONNULL (__has_attribute(nonnull))
# define V8_HAS_ATTRIBUTE_NOINLINE (__has_attribute(noinline))
# define V8_HAS_ATTRIBUTE_UNUSED (__has_attribute(unused))
# define V8_HAS_ATTRIBUTE_VISIBILITY (__has_attribute(visibility))
# define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT \
(__has_attribute(warn_unused_result))
# define V8_HAS_CPP_ATTRIBUTE_NODISCARD (V8_HAS_CPP_ATTRIBUTE(nodiscard))
# define V8_HAS_BUILTIN_ASSUME_ALIGNED (__has_builtin(__builtin_assume_aligned))
# define V8_HAS_BUILTIN_BSWAP16 (__has_builtin(__builtin_bswap16))
# define V8_HAS_BUILTIN_BSWAP32 (__has_builtin(__builtin_bswap32))
# define V8_HAS_BUILTIN_BSWAP64 (__has_builtin(__builtin_bswap64))
# define V8_HAS_BUILTIN_CLZ (__has_builtin(__builtin_clz))
# define V8_HAS_BUILTIN_CTZ (__has_builtin(__builtin_ctz))
# define V8_HAS_BUILTIN_EXPECT (__has_builtin(__builtin_expect))
# define V8_HAS_BUILTIN_FRAME_ADDRESS (__has_builtin(__builtin_frame_address))
# define V8_HAS_BUILTIN_POPCOUNT (__has_builtin(__builtin_popcount))
# define V8_HAS_BUILTIN_SADD_OVERFLOW (__has_builtin(__builtin_sadd_overflow))
# define V8_HAS_BUILTIN_SSUB_OVERFLOW (__has_builtin(__builtin_ssub_overflow))
# define V8_HAS_BUILTIN_UADD_OVERFLOW (__has_builtin(__builtin_uadd_overflow))
// Clang has no __has_feature for computed gotos.
// GCC doc: https://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html
# define V8_HAS_COMPUTED_GOTO 1
// Whether constexpr has full C++14 semantics, in particular that non-constexpr
// code is allowed as long as it's not executed for any constexpr instantiation.
# define V8_HAS_CXX14_CONSTEXPR 1
#elif defined(__GNUC__)
# define V8_CC_GNU 1
# if defined(__INTEL_COMPILER) // Intel C++ also masquerades as GCC 3.2.0
# define V8_CC_INTEL 1
# endif
# if defined(__MINGW32__)
# define V8_CC_MINGW32 1
# endif
# if defined(__MINGW64__)
# define V8_CC_MINGW64 1
# endif
# define V8_CC_MINGW (V8_CC_MINGW32 || V8_CC_MINGW64)
// always_inline is available in gcc 4.0 but not very reliable until 4.4.
// Works around "sorry, unimplemented: inlining failed" build errors with
// older compilers.
# define V8_HAS_ATTRIBUTE_ALWAYS_INLINE 1
# define V8_HAS_ATTRIBUTE_NOINLINE 1
# define V8_HAS_ATTRIBUTE_UNUSED 1
# define V8_HAS_ATTRIBUTE_VISIBILITY 1
# define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT (!V8_CC_INTEL)
# define V8_HAS_CPP_ATTRIBUTE_NODISCARD (V8_HAS_CPP_ATTRIBUTE(nodiscard))
# define V8_HAS_BUILTIN_ASSUME_ALIGNED 1
# define V8_HAS_BUILTIN_CLZ 1
# define V8_HAS_BUILTIN_CTZ 1
# define V8_HAS_BUILTIN_EXPECT 1
# define V8_HAS_BUILTIN_FRAME_ADDRESS 1
# define V8_HAS_BUILTIN_POPCOUNT 1
// GCC doc: https://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html
#define V8_HAS_COMPUTED_GOTO 1
// Whether constexpr has full C++14 semantics, in particular that non-constexpr
// code is allowed as long as it's not executed for any constexpr instantiation.
// GCC only supports this since version 6.
# define V8_HAS_CXX14_CONSTEXPR (V8_GNUC_PREREQ(6, 0, 0))
#endif
#if defined(_MSC_VER)
# define V8_CC_MSVC 1
# define V8_HAS_DECLSPEC_NOINLINE 1
# define V8_HAS_DECLSPEC_SELECTANY 1
# define V8_HAS___FORCEINLINE 1
#endif
// -----------------------------------------------------------------------------
// Helper macros
// A macro used to make better inlining. Don't bother for debug builds.
// Use like:
// V8_INLINE int GetZero() { return 0; }
#if !defined(DEBUG) && V8_HAS_ATTRIBUTE_ALWAYS_INLINE
# define V8_INLINE inline __attribute__((always_inline))
#elif !defined(DEBUG) && V8_HAS___FORCEINLINE
# define V8_INLINE __forceinline
#else
# define V8_INLINE inline
#endif
#if V8_HAS_BUILTIN_ASSUME_ALIGNED
# define V8_ASSUME_ALIGNED(ptr, alignment) \
__builtin_assume_aligned((ptr), (alignment))
#else
# define V8_ASSUME_ALIGNED(ptr, alignment) (ptr)
#endif
// A macro to mark specific arguments as non-null.
// Use like:
// int add(int* x, int y, int* z) V8_NONNULL(1, 3) { return *x + y + *z; }
#if V8_HAS_ATTRIBUTE_NONNULL
# define V8_NONNULL(...) __attribute__((nonnull(__VA_ARGS__)))
#else
# define V8_NONNULL(...) /* NOT SUPPORTED */
#endif
// A macro used to tell the compiler to never inline a particular function.
// Use like:
// V8_NOINLINE int GetMinusOne() { return -1; }
#if V8_HAS_ATTRIBUTE_NOINLINE
# define V8_NOINLINE __attribute__((noinline))
#elif V8_HAS_DECLSPEC_NOINLINE
# define V8_NOINLINE __declspec(noinline)
#else
# define V8_NOINLINE /* NOT SUPPORTED */
#endif
// A macro (V8_DEPRECATED) to mark classes or functions as deprecated.
#if defined(V8_DEPRECATION_WARNINGS)
# define V8_DEPRECATED(message) [[deprecated(message)]]
#else
# define V8_DEPRECATED(message)
#endif
// A macro (V8_DEPRECATE_SOON) to make it easier to see what will be deprecated.
#if defined(V8_IMMINENT_DEPRECATION_WARNINGS)
# define V8_DEPRECATE_SOON(message) [[deprecated(message)]]
#else
# define V8_DEPRECATE_SOON(message)
#endif
#if defined(__GNUC__) && !defined(__clang__) && (__GNUC__ < 6)
# define V8_ENUM_DEPRECATED(message)
# define V8_ENUM_DEPRECATE_SOON(message)
#else
# define V8_ENUM_DEPRECATED(message) V8_DEPRECATED(message)
# define V8_ENUM_DEPRECATE_SOON(message) V8_DEPRECATE_SOON(message)
#endif
// A macro to provide the compiler with branch prediction information.
#if V8_HAS_BUILTIN_EXPECT
# define V8_UNLIKELY(condition) (__builtin_expect(!!(condition), 0))
# define V8_LIKELY(condition) (__builtin_expect(!!(condition), 1))
#else
# define V8_UNLIKELY(condition) (condition)
# define V8_LIKELY(condition) (condition)
#endif
// Annotate a function indicating the caller must examine the return value.
// Use like:
// int foo() V8_WARN_UNUSED_RESULT;
#if V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
#define V8_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
#else
#define V8_WARN_UNUSED_RESULT /* NOT SUPPORTED */
#endif
// Annotate a class or constructor indicating the caller must assign the
// constructed instances.
// Apply to the whole class like:
// class V8_NODISCARD Foo() { ... };
// or apply to just one constructor like:
// V8_NODISCARD Foo() { ... };
// [[nodiscard]] comes in C++17 but supported in clang with -std >= c++11.
#if V8_HAS_CPP_ATTRIBUTE_NODISCARD
#define V8_NODISCARD [[nodiscard]]
#else
#define V8_NODISCARD /* NOT SUPPORTED */
#endif
// Helper macro to define no_sanitize attributes only with clang.
#if defined(__clang__) && defined(__has_attribute)
#if __has_attribute(no_sanitize)
#define V8_CLANG_NO_SANITIZE(what) __attribute__((no_sanitize(what)))
#endif
#endif
#if !defined(V8_CLANG_NO_SANITIZE)
#define V8_CLANG_NO_SANITIZE(what)
#endif
#if defined(BUILDING_V8_SHARED) && defined(USING_V8_SHARED)
#error Inconsistent build configuration: To build the V8 shared library \
set BUILDING_V8_SHARED, to include its headers for linking against the \
V8 shared library set USING_V8_SHARED.
#endif
#ifdef V8_OS_WIN
// Setup for Windows DLL export/import. When building the V8 DLL the
// BUILDING_V8_SHARED needs to be defined. When building a program which uses
// the V8 DLL USING_V8_SHARED needs to be defined. When either building the V8
// static library or building a program which uses the V8 static library neither
// BUILDING_V8_SHARED nor USING_V8_SHARED should be defined.
#ifdef BUILDING_V8_SHARED
# define V8_EXPORT __declspec(dllexport)
#elif USING_V8_SHARED
# define V8_EXPORT __declspec(dllimport)
#else
# define V8_EXPORT
#endif // BUILDING_V8_SHARED
#else // V8_OS_WIN
// Setup for Linux shared library export.
#if V8_HAS_ATTRIBUTE_VISIBILITY
# ifdef BUILDING_V8_SHARED
# define V8_EXPORT __attribute__ ((visibility("default")))
# else
# define V8_EXPORT
# endif
#else
# define V8_EXPORT
#endif
#endif // V8_OS_WIN
// clang-format on
#undef V8_HAS_CPP_ATTRIBUTE
#endif // V8CONFIG_H_