v8  4.6.85(node5.12.0)
V8 is Google's open source JavaScript engine
v8config.h
Go to the documentation of this file.
1 // Copyright 2013 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8CONFIG_H_
6 #define V8CONFIG_H_
7 
8 // clang-format off
9 
10 // Platform headers for feature detection below.
11 #if defined(__ANDROID__)
12 # include <sys/cdefs.h>
13 #elif defined(__APPLE__)
14 # include <TargetConditionals.h>
15 #elif defined(__linux__)
16 # include <features.h>
17 #endif
18 
19 
20 // This macro allows to test for the version of the GNU C library (or
21 // a compatible C library that masquerades as glibc). It evaluates to
22 // 0 if libc is not GNU libc or compatible.
23 // Use like:
24 // #if V8_GLIBC_PREREQ(2, 3)
25 // ...
26 // #endif
27 #if defined(__GLIBC__) && defined(__GLIBC_MINOR__)
28 # define V8_GLIBC_PREREQ(major, minor)
29  ((__GLIBC__ * 100 + __GLIBC_MINOR__) >= ((major) * 100 + (minor)))
30 #else
31 # define V8_GLIBC_PREREQ(major, minor) 0
32 #endif
33 
34 
35 // This macro allows to test for the version of the GNU C++ compiler.
36 // Note that this also applies to compilers that masquerade as GCC,
37 // for example clang and the Intel C++ compiler for Linux.
38 // Use like:
39 // #if V8_GNUC_PREREQ(4, 3, 1)
40 // ...
41 // #endif
42 #if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
43 # define V8_GNUC_PREREQ(major, minor, patchlevel)
44  ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) >=
45  ((major) * 10000 + (minor) * 100 + (patchlevel)))
46 #elif defined(__GNUC__) && defined(__GNUC_MINOR__)
47 # define V8_GNUC_PREREQ(major, minor, patchlevel)
48  ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >=
49  ((major) * 10000 + (minor) * 100 + (patchlevel)))
50 #else
51 # define V8_GNUC_PREREQ(major, minor, patchlevel) 0
52 #endif
53 
54 
55 
56 // -----------------------------------------------------------------------------
57 // Operating system detection
58 //
59 // V8_OS_ANDROID - Android
60 // V8_OS_BSD - BSDish (Mac OS X, Net/Free/Open/DragonFlyBSD)
61 // V8_OS_CYGWIN - Cygwin
62 // V8_OS_DRAGONFLYBSD - DragonFlyBSD
63 // V8_OS_FREEBSD - FreeBSD
64 // V8_OS_LINUX - Linux
65 // V8_OS_MACOSX - Mac OS X
66 // V8_OS_NACL - Native Client
67 // V8_OS_NETBSD - NetBSD
68 // V8_OS_OPENBSD - OpenBSD
69 // V8_OS_POSIX - POSIX compatible (mostly everything except Windows)
70 // V8_OS_QNX - QNX Neutrino
71 // V8_OS_SOLARIS - Sun Solaris and OpenSolaris
72 // V8_OS_AIX - AIX
73 // V8_OS_WIN - Microsoft Windows
74 
75 #if defined(__ANDROID__)
76 # define V8_OS_ANDROID 1
77 # define V8_OS_LINUX 1
78 # define V8_OS_POSIX 1
79 #elif defined(__APPLE__)
80 # define V8_OS_BSD 1
81 # define V8_OS_MACOSX 1
82 # define V8_OS_POSIX 1
83 #elif defined(__native_client__)
84 # define V8_OS_NACL 1
85 # define V8_OS_POSIX 1
86 #elif defined(__CYGWIN__)
87 # define V8_OS_CYGWIN 1
88 # define V8_OS_POSIX 1
89 #elif defined(__linux__)
90 # define V8_OS_LINUX 1
91 # define V8_OS_POSIX 1
92 #elif defined(__sun)
93 # define V8_OS_POSIX 1
94 # define V8_OS_SOLARIS 1
95 #elif defined(_AIX)
96 #define V8_OS_POSIX 1
97 #define V8_OS_AIX 1
98 #elif defined(__FreeBSD__)
99 # define V8_OS_BSD 1
100 # define V8_OS_FREEBSD 1
101 # define V8_OS_POSIX 1
102 #elif defined(__DragonFly__)
103 # define V8_OS_BSD 1
104 # define V8_OS_DRAGONFLYBSD 1
105 # define V8_OS_POSIX 1
106 #elif defined(__NetBSD__)
107 # define V8_OS_BSD 1
108 # define V8_OS_NETBSD 1
109 # define V8_OS_POSIX 1
110 #elif defined(__OpenBSD__)
111 # define V8_OS_BSD 1
112 # define V8_OS_OPENBSD 1
113 # define V8_OS_POSIX 1
114 #elif defined(__QNXNTO__)
115 # define V8_OS_POSIX 1
116 # define V8_OS_QNX 1
117 #elif defined(_WIN32)
118 # define V8_OS_WIN 1
119 #endif
120 
121 
122 // -----------------------------------------------------------------------------
123 // C library detection
124 //
125 // V8_LIBC_MSVCRT - MSVC libc
126 // V8_LIBC_BIONIC - Bionic libc
127 // V8_LIBC_BSD - BSD libc derivate
128 // V8_LIBC_GLIBC - GNU C library
129 // V8_LIBC_UCLIBC - uClibc
130 //
131 // Note that testing for libc must be done using #if not #ifdef. For example,
132 // to test for the GNU C library, use:
133 // #if V8_LIBC_GLIBC
134 // ...
135 // #endif
136 
137 #if defined (_MSC_VER)
138 # define V8_LIBC_MSVCRT 1
139 #elif defined(__BIONIC__)
140 # define V8_LIBC_BIONIC 1
141 # define V8_LIBC_BSD 1
142 #elif defined(__UCLIBC__)
143 // Must test for UCLIBC before GLIBC, as UCLIBC pretends to be GLIBC.
144 # define V8_LIBC_UCLIBC 1
145 #elif defined(__GLIBC__) || defined(__GNU_LIBRARY__)
146 # define V8_LIBC_GLIBC 1
147 #else
148 # define V8_LIBC_BSD V8_OS_BSD
149 #endif
150 
151 
152 // -----------------------------------------------------------------------------
153 // Compiler detection
154 //
155 // V8_CC_GNU - GCC, or clang in gcc mode
156 // V8_CC_INTEL - Intel C++
157 // V8_CC_MINGW - Minimalist GNU for Windows
158 // V8_CC_MINGW32 - Minimalist GNU for Windows (mingw32)
159 // V8_CC_MINGW64 - Minimalist GNU for Windows (mingw-w64)
160 // V8_CC_MSVC - Microsoft Visual C/C++, or clang in cl.exe mode
161 //
162 // C++11 feature detection
163 //
164 // V8_HAS_CXX11_ALIGNAS - alignas specifier supported
165 // V8_HAS_CXX11_ALIGNOF - alignof(type) operator supported
166 // V8_HAS_CXX11_STATIC_ASSERT - static_assert() supported
167 //
168 // Compiler-specific feature detection
169 //
170 // V8_HAS___ALIGNOF - __alignof(type) operator supported
171 // V8_HAS___ALIGNOF__ - __alignof__(type) operator supported
172 // V8_HAS_ATTRIBUTE_ALIGNED - __attribute__((aligned(n))) supported
173 // V8_HAS_ATTRIBUTE_ALWAYS_INLINE - __attribute__((always_inline))
174 // supported
175 // V8_HAS_ATTRIBUTE_DEPRECATED - __attribute__((deprecated)) supported
176 // V8_HAS_ATTRIBUTE_NOINLINE - __attribute__((noinline)) supported
177 // V8_HAS_ATTRIBUTE_UNUSED - __attribute__((unused)) supported
178 // V8_HAS_ATTRIBUTE_VISIBILITY - __attribute__((visibility)) supported
179 // V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT - __attribute__((warn_unused_result))
180 // supported
181 // V8_HAS_BUILTIN_CLZ - __builtin_clz() supported
182 // V8_HAS_BUILTIN_CTZ - __builtin_ctz() supported
183 // V8_HAS_BUILTIN_EXPECT - __builtin_expect() supported
184 // V8_HAS_BUILTIN_FRAME_ADDRESS - __builtin_frame_address() supported
185 // V8_HAS_BUILTIN_POPCOUNT - __builtin_popcount() supported
186 // V8_HAS_BUILTIN_SADD_OVERFLOW - __builtin_sadd_overflow() supported
187 // V8_HAS_BUILTIN_SSUB_OVERFLOW - __builtin_ssub_overflow() supported
188 // V8_HAS_BUILTIN_UADD_OVERFLOW - __builtin_uadd_overflow() supported
189 // V8_HAS_DECLSPEC_ALIGN - __declspec(align(n)) supported
190 // V8_HAS_DECLSPEC_DEPRECATED - __declspec(deprecated) supported
191 // V8_HAS_DECLSPEC_NOINLINE - __declspec(noinline) supported
192 // V8_HAS_DECLSPEC_SELECTANY - __declspec(selectany) supported
193 // V8_HAS___FORCEINLINE - __forceinline supported
194 //
195 // Note that testing for compilers and/or features must be done using #if
196 // not #ifdef. For example, to test for Intel C++ Compiler, use:
197 // #if V8_CC_INTEL
198 // ...
199 // #endif
200 
201 #if defined(__clang__)
202 
203 #if defined(__GNUC__) // Clang in gcc mode.
204 # define V8_CC_GNU 1
205 #endif
206 
207 // Clang defines __alignof__ as alias for __alignof
208 # define V8_HAS___ALIGNOF 1
209 # define V8_HAS___ALIGNOF__ V8_HAS___ALIGNOF
210 
211 # define V8_HAS_ATTRIBUTE_ALIGNED (__has_attribute(aligned))
212 # define V8_HAS_ATTRIBUTE_ALWAYS_INLINE (__has_attribute(always_inline))
213 # define V8_HAS_ATTRIBUTE_DEPRECATED (__has_attribute(deprecated))
214 # define V8_HAS_ATTRIBUTE_NOINLINE (__has_attribute(noinline))
215 # define V8_HAS_ATTRIBUTE_UNUSED (__has_attribute(unused))
216 # define V8_HAS_ATTRIBUTE_VISIBILITY (__has_attribute(visibility))
217 # define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
218  (__has_attribute(warn_unused_result))
219 
220 # define V8_HAS_BUILTIN_CLZ (__has_builtin(__builtin_clz))
221 # define V8_HAS_BUILTIN_CTZ (__has_builtin(__builtin_ctz))
222 # define V8_HAS_BUILTIN_EXPECT (__has_builtin(__builtin_expect))
223 # define V8_HAS_BUILTIN_FRAME_ADDRESS (__has_builtin(__builtin_frame_address))
224 # define V8_HAS_BUILTIN_POPCOUNT (__has_builtin(__builtin_popcount))
225 # define V8_HAS_BUILTIN_SADD_OVERFLOW (__has_builtin(__builtin_sadd_overflow))
226 # define V8_HAS_BUILTIN_SSUB_OVERFLOW (__has_builtin(__builtin_ssub_overflow))
227 # define V8_HAS_BUILTIN_UADD_OVERFLOW (__has_builtin(__builtin_uadd_overflow))
228 
229 # define V8_HAS_CXX11_ALIGNAS (__has_feature(cxx_alignas))
230 # define V8_HAS_CXX11_STATIC_ASSERT (__has_feature(cxx_static_assert))
231 
232 #elif defined(__GNUC__)
233 
234 # define V8_CC_GNU 1
235 # if defined(__INTEL_COMPILER) // Intel C++ also masquerades as GCC 3.2.0
236 # define V8_CC_INTEL 1
237 # endif
238 # if defined(__MINGW32__)
239 # define V8_CC_MINGW32 1
240 # endif
241 # if defined(__MINGW64__)
242 # define V8_CC_MINGW64 1
243 # endif
244 # define V8_CC_MINGW (V8_CC_MINGW32 || V8_CC_MINGW64)
245 
246 # define V8_HAS___ALIGNOF__ (V8_GNUC_PREREQ(4, 3, 0))
247 
248 # define V8_HAS_ATTRIBUTE_ALIGNED (V8_GNUC_PREREQ(2, 95, 0))
249 // always_inline is available in gcc 4.0 but not very reliable until 4.4.
250 // Works around "sorry, unimplemented: inlining failed" build errors with
251 // older compilers.
252 # define V8_HAS_ATTRIBUTE_ALWAYS_INLINE (V8_GNUC_PREREQ(4, 4, 0))
253 # define V8_HAS_ATTRIBUTE_DEPRECATED (V8_GNUC_PREREQ(3, 4, 0))
254 # define V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE (V8_GNUC_PREREQ(4, 5, 0))
255 # define V8_HAS_ATTRIBUTE_NOINLINE (V8_GNUC_PREREQ(3, 4, 0))
256 # define V8_HAS_ATTRIBUTE_UNUSED (V8_GNUC_PREREQ(2, 95, 0))
257 # define V8_HAS_ATTRIBUTE_VISIBILITY (V8_GNUC_PREREQ(4, 3, 0))
258 # define V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
259  (!V8_CC_INTEL && V8_GNUC_PREREQ(4, 1, 0))
260 
261 # define V8_HAS_BUILTIN_CLZ (V8_GNUC_PREREQ(3, 4, 0))
262 # define V8_HAS_BUILTIN_CTZ (V8_GNUC_PREREQ(3, 4, 0))
263 # define V8_HAS_BUILTIN_EXPECT (V8_GNUC_PREREQ(2, 96, 0))
264 # define V8_HAS_BUILTIN_FRAME_ADDRESS (V8_GNUC_PREREQ(2, 96, 0))
265 # define V8_HAS_BUILTIN_POPCOUNT (V8_GNUC_PREREQ(3, 4, 0))
266 
267 // g++ requires -std=c++0x or -std=gnu++0x to support C++11 functionality
268 // without warnings (functionality used by the macros below). These modes
269 // are detectable by checking whether __GXX_EXPERIMENTAL_CXX0X__ is defined or,
270 // more standardly, by checking whether __cplusplus has a C++11 or greater
271 // value. Current versions of g++ do not correctly set __cplusplus, so we check
272 // both for forward compatibility.
273 # if defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L
274 # define V8_HAS_CXX11_ALIGNAS (V8_GNUC_PREREQ(4, 8, 0))
275 # define V8_HAS_CXX11_ALIGNOF (V8_GNUC_PREREQ(4, 8, 0))
276 # define V8_HAS_CXX11_STATIC_ASSERT (V8_GNUC_PREREQ(4, 3, 0))
277 # endif
278 #endif
279 
280 #if defined(_MSC_VER)
281 # define V8_CC_MSVC 1
282 # define V8_HAS___ALIGNOF 1
283 
284 # define V8_HAS_DECLSPEC_ALIGN 1
285 # define V8_HAS_DECLSPEC_DEPRECATED 1
286 # define V8_HAS_DECLSPEC_NOINLINE 1
287 # define V8_HAS_DECLSPEC_SELECTANY 1
288 
289 # define V8_HAS___FORCEINLINE 1
290 
291 #endif
292 
293 
294 // -----------------------------------------------------------------------------
295 // Helper macros
296 
297 // A macro used to make better inlining. Don't bother for debug builds.
298 // Use like:
299 // V8_INLINE int GetZero() { return 0; }
300 #if !defined(DEBUG) && V8_HAS_ATTRIBUTE_ALWAYS_INLINE
301 # define V8_INLINE inline __attribute__((always_inline))
302 #elif !defined(DEBUG) && V8_HAS___FORCEINLINE
303 # define V8_INLINE __forceinline
304 #else
305 # define V8_INLINE inline
306 #endif
307 
308 
309 // A macro used to tell the compiler to never inline a particular function.
310 // Don't bother for debug builds.
311 // Use like:
312 // V8_NOINLINE int GetMinusOne() { return -1; }
313 #if !defined(DEBUG) && V8_HAS_ATTRIBUTE_NOINLINE
314 # define V8_NOINLINE __attribute__((noinline))
315 #elif !defined(DEBUG) && V8_HAS_DECLSPEC_NOINLINE
316 # define V8_NOINLINE __declspec(noinline)
317 #else
318 # define V8_NOINLINE /* NOT SUPPORTED */
319 #endif
320 
321 
322 // A macro (V8_DEPRECATED) to mark classes or functions as deprecated.
323 #if defined(V8_DEPRECATION_WARNINGS) && V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE
324 #define V8_DEPRECATED(message, declarator)
325  declarator __attribute__((deprecated(message)))
326 #elif defined(V8_DEPRECATION_WARNINGS) && V8_HAS_ATTRIBUTE_DEPRECATED
327 #define V8_DEPRECATED(message, declarator)
328  declarator __attribute__((deprecated))
329 #elif defined(V8_DEPRECATION_WARNINGS) && V8_HAS_DECLSPEC_DEPRECATED
330 #define V8_DEPRECATED(message, declarator) __declspec(deprecated) declarator
331 #else
332 #define V8_DEPRECATED(message, declarator) declarator
333 #endif
334 
335 
336 // A macro (V8_DEPRECATE_SOON) to make it easier to see what will be deprecated.
337 #if defined(V8_IMMINENT_DEPRECATION_WARNINGS) &&
338  V8_HAS_ATTRIBUTE_DEPRECATED_MESSAGE
339 #define V8_DEPRECATE_SOON(message, declarator)
340  declarator __attribute__((deprecated(message)))
341 #elif defined(V8_IMMINENT_DEPRECATION_WARNINGS) && V8_HAS_ATTRIBUTE_DEPRECATED
342 #define V8_DEPRECATE_SOON(message, declarator)
343  declarator __attribute__((deprecated))
344 #elif defined(V8_IMMINENT_DEPRECATION_WARNINGS) && V8_HAS_DECLSPEC_DEPRECATED
345 #define V8_DEPRECATE_SOON(message, declarator) __declspec(deprecated) declarator
346 #else
347 #define V8_DEPRECATE_SOON(message, declarator) declarator
348 #endif
349 
350 
351 // A macro to provide the compiler with branch prediction information.
352 #if V8_HAS_BUILTIN_EXPECT
353 # define V8_UNLIKELY(condition) (__builtin_expect(!!(condition), 0))
354 # define V8_LIKELY(condition) (__builtin_expect(!!(condition), 1))
355 #else
356 # define V8_UNLIKELY(condition) (condition)
357 # define V8_LIKELY(condition) (condition)
358 #endif
359 
360 
361 // This macro allows to specify memory alignment for structs, classes, etc.
362 // Use like:
363 // class V8_ALIGNED(16) MyClass { ... };
364 // V8_ALIGNED(32) int array[42];
365 #if V8_HAS_CXX11_ALIGNAS
366 # define V8_ALIGNED(n) alignas(n)
367 #elif V8_HAS_ATTRIBUTE_ALIGNED
368 # define V8_ALIGNED(n) __attribute__((aligned(n)))
369 #elif V8_HAS_DECLSPEC_ALIGN
370 # define V8_ALIGNED(n) __declspec(align(n))
371 #else
372 # define V8_ALIGNED(n) /* NOT SUPPORTED */
373 #endif
374 
375 
376 // This macro is similar to V8_ALIGNED(), but takes a type instead of size
377 // in bytes. If the compiler does not supports using the alignment of the
378 // |type|, it will align according to the |alignment| instead. For example,
379 // Visual Studio C++ cannot combine __declspec(align) and __alignof. The
380 // |alignment| must be a literal that is used as a kind of worst-case fallback
381 // alignment.
382 // Use like:
383 // struct V8_ALIGNAS(AnotherClass, 16) NewClass { ... };
384 // V8_ALIGNAS(double, 8) int array[100];
385 #if V8_HAS_CXX11_ALIGNAS
386 # define V8_ALIGNAS(type, alignment) alignas(type)
387 #elif V8_HAS___ALIGNOF__ && V8_HAS_ATTRIBUTE_ALIGNED
388 # define V8_ALIGNAS(type, alignment) __attribute__((aligned(__alignof__(type))))
389 #else
390 # define V8_ALIGNAS(type, alignment) V8_ALIGNED(alignment)
391 #endif
392 
393 
394 // This macro returns alignment in bytes (an integer power of two) required for
395 // any instance of the given type, which is either complete type, an array type,
396 // or a reference type.
397 // Use like:
398 // size_t alignment = V8_ALIGNOF(double);
399 #if V8_HAS_CXX11_ALIGNOF
400 # define V8_ALIGNOF(type) alignof(type)
401 #elif V8_HAS___ALIGNOF
402 # define V8_ALIGNOF(type) __alignof(type)
403 #elif V8_HAS___ALIGNOF__
404 # define V8_ALIGNOF(type) __alignof__(type)
405 #else
406 // Note that alignment of a type within a struct can be less than the
407 // alignment of the type stand-alone (because of ancient ABIs), so this
408 // should only be used as a last resort.
409 namespace v8 { template <typename T> class AlignOfHelper { char c; T t; }; }
410 # define V8_ALIGNOF(type) (sizeof(::v8::AlignOfHelper<type>) - sizeof(type))
411 #endif
412 
413 // Annotate a function indicating the caller must examine the return value.
414 // Use like:
415 // int foo() WARN_UNUSED_RESULT;
416 #if V8_HAS_ATTRIBUTE_WARN_UNUSED_RESULT
417 #define V8_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
418 #else
419 #define V8_WARN_UNUSED_RESULT /* NOT SUPPORTED */
420 #endif
421 
422 // clang-format on
423 
424 #endif // V8CONFIG_H_