api/v6.2/v8config_8h_source.html

// 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

//

//  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_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_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

#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(_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


// -----------------------------------------------------------------------------

// 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

//

//  V8_HAS_CXX11_ALIGNAS        - alignas specifier supported

//  V8_HAS_CXX11_ALIGNOF        - alignof(type) operator supported

//

// Compiler-specific feature detection

//

//  V8_HAS___ALIGNOF                    - __alignof(type) operator supported

//  V8_HAS___ALIGNOF__                  - __alignof__(type) operator supported

//  V8_HAS_ATTRIBUTE_ALIGNED            - __attribute__((aligned(n))) supported

//  V8_HAS_ATTRIBUTE_ALWAYS_INLINE      - __attribute__((always_inline))

//                                        supported

//  V8_HAS_ATTRIBUTE_DEPRECATED         - __attribute__((deprecated)) 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_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_DECLSPEC_ALIGN               - __declspec(align(n)) supported

//  V8_HAS_DECLSPEC_DEPRECATED          - __declspec(deprecated) supported

//  V8_HAS_DECLSPEC_NOINLINE            - __declspec(noinline) supported

//  V8_HAS_DECLSPEC_SELECTANY           - __declspec(selectany) supported

//  V8_HAS_DECLSPEC_NORETURN            - __declspec(noreturn) 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(__clang__)


#if defined(__GNUC__)  // Clang in gcc mode.

# define V8_CC_GNU 1

#endif


// Clang defines __alignof__ as alias for __alignof

# define V8_HAS___ALIGNOF 1

# define V8_HAS___ALIGNOF__ V8_HAS___ALIGNOF


# define V8_HAS_ATTRIBUTE_ALIGNED (__has_attribute(aligned))

# define V8_HAS_ATTRIBUTE_ALWAYS_INLINE (__has_attribute(always_inline))

# define V8_HAS_ATTRIBUTE_DEPRECATED (__has_attribute(deprecated))

# 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_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))


# define V8_HAS_CXX11_ALIGNAS (__has_feature(cxx_alignas))


#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)


# define V8_HAS___ALIGNOF__ (V8_GNUC_PREREQ(4, 3, 0))


# define V8_HAS_ATTRIBUTE_ALIGNED (V8_GNUC_PREREQ(2, 95, 0))

// 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 (V8_GNUC_PREREQ(4, 4, 0))

# define V8_HAS_ATTRIBUTE_DEPRECATED (V8_GNUC_PREREQ(3, 4, 0))

# define V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE (V8_GNUC_PREREQ(4, 5, 0))

# define V8_HAS_ATTRIBUTE_NOINLINE (V8_GNUC_PREREQ(3, 4, 0))

# define V8_HAS_ATTRIBUTE_UNUSED (V8_GNUC_PREREQ(2, 95, 0))

# define V8_HAS_ATTRIBUTE_VISIBILITY (V8_GNUC_PREREQ(4, 3, 0))

# define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT \

    (!V8_CC_INTEL && V8_GNUC_PREREQ(4, 1, 0))


# define V8_HAS_BUILTIN_CLZ (V8_GNUC_PREREQ(3, 4, 0))

# define V8_HAS_BUILTIN_CTZ (V8_GNUC_PREREQ(3, 4, 0))

# define V8_HAS_BUILTIN_EXPECT (V8_GNUC_PREREQ(2, 96, 0))

# define V8_HAS_BUILTIN_FRAME_ADDRESS (V8_GNUC_PREREQ(2, 96, 0))

# define V8_HAS_BUILTIN_POPCOUNT (V8_GNUC_PREREQ(3, 4, 0))


# if __cplusplus >= 201103L

#  define V8_HAS_CXX11_ALIGNAS (V8_GNUC_PREREQ(4, 8, 0))

#  define V8_HAS_CXX11_ALIGNOF (V8_GNUC_PREREQ(4, 8, 0))

# endif

#endif


#if defined(_MSC_VER)

# define V8_CC_MSVC 1

# define V8_HAS___ALIGNOF 1


# define V8_HAS_DECLSPEC_ALIGN 1

# define V8_HAS_DECLSPEC_DEPRECATED 1

# define V8_HAS_DECLSPEC_NOINLINE 1

# define V8_HAS_DECLSPEC_SELECTANY 1

# define V8_HAS_DECLSPEC_NORETURN 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


// A macro used to tell the compiler to never inline a particular function.

// Don't bother for debug builds.

// Use like:

//   V8_NOINLINE int GetMinusOne() { return -1; }

#if !defined(DEBUG) && V8_HAS_ATTRIBUTE_NOINLINE

# define V8_NOINLINE __attribute__((noinline))

#elif !defined(DEBUG) && 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) && V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE

#define V8_DEPRECATED(message, declarator) \

  declarator __attribute__((deprecated(message)))

#elif defined(V8_DEPRECATION_WARNINGS) && V8_HAS_ATTRIBUTE_DEPRECATED

#define V8_DEPRECATED(message, declarator) \

  declarator __attribute__((deprecated))

#elif defined(V8_DEPRECATION_WARNINGS) && V8_HAS_DECLSPEC_DEPRECATED

#define V8_DEPRECATED(message, declarator) __declspec(deprecated) declarator

#else

#define V8_DEPRECATED(message, declarator) declarator

#endif


// A macro (V8_DEPRECATE_SOON) to make it easier to see what will be deprecated.

#if defined(V8_IMMINENT_DEPRECATION_WARNINGS) && \

    V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE

#define V8_DEPRECATE_SOON(message, declarator) \

  declarator __attribute__((deprecated(message)))

#elif defined(V8_IMMINENT_DEPRECATION_WARNINGS) && V8_HAS_ATTRIBUTE_DEPRECATED

#define V8_DEPRECATE_SOON(message, declarator) \

  declarator __attribute__((deprecated))

#elif defined(V8_IMMINENT_DEPRECATION_WARNINGS) && V8_HAS_DECLSPEC_DEPRECATED

#define V8_DEPRECATE_SOON(message, declarator) __declspec(deprecated) declarator

#else

#define V8_DEPRECATE_SOON(message, declarator) declarator

#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


// This macro allows to specify memory alignment for structs, classes, etc.

// Use like:

//   class V8_ALIGNED(16) MyClass { ... };

//   V8_ALIGNED(32) int array[42];

#if V8_HAS_CXX11_ALIGNAS

# define V8_ALIGNED(n) alignas(n)

#elif V8_HAS_ATTRIBUTE_ALIGNED

# define V8_ALIGNED(n) __attribute__((aligned(n)))

#elif V8_HAS_DECLSPEC_ALIGN

# define V8_ALIGNED(n) __declspec(align(n))

#else

# define V8_ALIGNED(n) /* NOT SUPPORTED */

#endif


// This macro is similar to V8_ALIGNED(), but takes a type instead of size

// in bytes. If the compiler does not supports using the alignment of the

// |type|, it will align according to the |alignment| instead. For example,

// Visual Studio C++ cannot combine __declspec(align) and __alignof. The

// |alignment| must be a literal that is used as a kind of worst-case fallback

// alignment.

// Use like:

//   struct V8_ALIGNAS(AnotherClass, 16) NewClass { ... };

//   V8_ALIGNAS(double, 8) int array[100];

#if V8_HAS_CXX11_ALIGNAS

# define V8_ALIGNAS(type, alignment) alignas(type)

#elif V8_HAS___ALIGNOF__ && V8_HAS_ATTRIBUTE_ALIGNED

# define V8_ALIGNAS(type, alignment) __attribute__((aligned(__alignof__(type))))

#else

# define V8_ALIGNAS(type, alignment) V8_ALIGNED(alignment)

#endif


// This macro returns alignment in bytes (an integer power of two) required for

// any instance of the given type, which is either complete type, an array type,

// or a reference type.

// Use like:

//   size_t alignment = V8_ALIGNOF(double);

#if V8_HAS_CXX11_ALIGNOF

# define V8_ALIGNOF(type) alignof(type)

#elif V8_HAS___ALIGNOF

# define V8_ALIGNOF(type) __alignof(type)

#elif V8_HAS___ALIGNOF__

# define V8_ALIGNOF(type) __alignof__(type)

#else

// Note that alignment of a type within a struct can be less than the

// alignment of the type stand-alone (because of ancient ABIs), so this

// should only be used as a last resort.

namespace v8 { template <typename T> class AlignOfHelper { char c; T t; }; }

# define V8_ALIGNOF(type) (sizeof(::v8::AlignOfHelper<type>) - sizeof(type))

#endif


// Annotate a function indicating the caller must examine the return value.

// Use like:

//   int foo() 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


// clang-format on


#endif  // V8CONFIG_H_

v8::AlignOfHelper
Definition: v8config.h:402

v8
Definition: libplatform.h:12