1 //===-- llvm/Support/Compiler.h - Compiler abstraction support --*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines several macros, based on the current compiler. This allows 11 // use of compiler-specific features in a way that remains portable. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_SUPPORT_COMPILER_H 16 #define LLVM_SUPPORT_COMPILER_H 17 18 #include "llvm/Config/llvm-config.h" 19 20 #ifndef __has_feature 21 # define __has_feature(x) 0 22 #endif 23 24 #ifndef __has_attribute 25 # define __has_attribute(x) 0 26 #endif 27 28 #ifndef __has_builtin 29 # define __has_builtin(x) 0 30 #endif 31 32 /// \macro __GNUC_PREREQ 33 /// \brief Defines __GNUC_PREREQ if glibc's features.h isn't available. 34 #ifndef __GNUC_PREREQ 35 # if defined(__GNUC__) && defined(__GNUC_MINOR__) 36 # define __GNUC_PREREQ(maj, min) \ 37 ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) 38 # else 39 # define __GNUC_PREREQ(maj, min) 0 40 # endif 41 #endif 42 43 /// \brief Does the compiler support r-value references? 44 /// This implies that <utility> provides the one-argument std::move; it 45 /// does not imply the existence of any other C++ library features. 46 #if (__has_feature(cxx_rvalue_references) \ 47 || defined(__GXX_EXPERIMENTAL_CXX0X__) \ 48 || (defined(_MSC_VER) && _MSC_VER >= 1600)) 49 #define LLVM_HAS_RVALUE_REFERENCES 1 50 #else 51 #define LLVM_HAS_RVALUE_REFERENCES 0 52 #endif 53 54 /// \brief Does the compiler support r-value reference *this? 55 /// 56 /// Sadly, this is separate from just r-value reference support because GCC 57 /// implemented everything but this thus far. No release of GCC yet has support 58 /// for this feature so it is enabled with Clang only. 59 /// FIXME: This should change to a version check when GCC grows support for it. 60 #if __has_feature(cxx_rvalue_references) 61 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1 62 #else 63 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0 64 #endif 65 66 /// \macro LLVM_HAS_CXX11_TYPETRAITS 67 /// \brief Does the compiler have the C++11 type traits. 68 /// 69 /// #include <type_traits> 70 /// 71 /// * enable_if 72 /// * {true,false}_type 73 /// * is_constructible 74 /// * etc... 75 #if defined(__GXX_EXPERIMENTAL_CXX0X__) \ 76 || (defined(_MSC_VER) && _MSC_VER >= 1700) 77 #define LLVM_HAS_CXX11_TYPETRAITS 1 78 #else 79 #define LLVM_HAS_CXX11_TYPETRAITS 0 80 #endif 81 82 /// \macro LLVM_HAS_CXX11_STDLIB 83 /// \brief Does the compiler have the C++11 standard library. 84 /// 85 /// Implies LLVM_HAS_RVALUE_REFERENCES, LLVM_HAS_CXX11_TYPETRAITS 86 #if defined(__GXX_EXPERIMENTAL_CXX0X__) \ 87 || (defined(_MSC_VER) && _MSC_VER >= 1700) 88 #define LLVM_HAS_CXX11_STDLIB 1 89 #else 90 #define LLVM_HAS_CXX11_STDLIB 0 91 #endif 92 93 /// \macro LLVM_HAS_VARIADIC_TEMPLATES 94 /// \brief Does this compiler support variadic templates. 95 /// 96 /// Implies LLVM_HAS_RVALUE_REFERENCES and the existence of std::forward. 97 #if __has_feature(cxx_variadic_templates) 98 # define LLVM_HAS_VARIADIC_TEMPLATES 1 99 #else 100 # define LLVM_HAS_VARIADIC_TEMPLATES 0 101 #endif 102 103 /// llvm_move - Expands to ::std::move if the compiler supports 104 /// r-value references; otherwise, expands to the argument. 105 #if LLVM_HAS_RVALUE_REFERENCES 106 #define llvm_move(value) (::std::move(value)) 107 #else 108 #define llvm_move(value) (value) 109 #endif 110 111 /// Expands to '&' if r-value references are supported. 112 /// 113 /// This can be used to provide l-value/r-value overrides of member functions. 114 /// The r-value override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS 115 #if LLVM_HAS_RVALUE_REFERENCE_THIS 116 #define LLVM_LVALUE_FUNCTION & 117 #else 118 #define LLVM_LVALUE_FUNCTION 119 #endif 120 121 /// LLVM_DELETED_FUNCTION - Expands to = delete if the compiler supports it. 122 /// Use to mark functions as uncallable. Member functions with this should 123 /// be declared private so that some behavior is kept in C++03 mode. 124 /// 125 /// class DontCopy { 126 /// private: 127 /// DontCopy(const DontCopy&) LLVM_DELETED_FUNCTION; 128 /// DontCopy &operator =(const DontCopy&) LLVM_DELETED_FUNCTION; 129 /// public: 130 /// ... 131 /// }; 132 #if (__has_feature(cxx_deleted_functions) \ 133 || defined(__GXX_EXPERIMENTAL_CXX0X__)) 134 // No version of MSVC currently supports this. 135 #define LLVM_DELETED_FUNCTION = delete 136 #else 137 #define LLVM_DELETED_FUNCTION 138 #endif 139 140 /// LLVM_FINAL - Expands to 'final' if the compiler supports it. 141 /// Use to mark classes or virtual methods as final. 142 #if __has_feature(cxx_override_control) \ 143 || (defined(_MSC_VER) && _MSC_VER >= 1700) 144 #define LLVM_FINAL final 145 #else 146 #define LLVM_FINAL 147 #endif 148 149 /// LLVM_OVERRIDE - Expands to 'override' if the compiler supports it. 150 /// Use to mark virtual methods as overriding a base class method. 151 #if __has_feature(cxx_override_control) \ 152 || (defined(_MSC_VER) && _MSC_VER >= 1700) 153 #define LLVM_OVERRIDE override 154 #else 155 #define LLVM_OVERRIDE 156 #endif 157 158 #if __has_feature(cxx_constexpr) || defined(__GXX_EXPERIMENTAL_CXX0X__) 159 # define LLVM_CONSTEXPR constexpr 160 #else 161 # define LLVM_CONSTEXPR 162 #endif 163 164 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked 165 /// into a shared library, then the class should be private to the library and 166 /// not accessible from outside it. Can also be used to mark variables and 167 /// functions, making them private to any shared library they are linked into. 168 /// On PE/COFF targets, library visibility is the default, so this isn't needed. 169 #if (__has_attribute(visibility) || __GNUC_PREREQ(4, 0)) && \ 170 !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(LLVM_ON_WIN32) 171 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden"))) 172 #else 173 #define LLVM_LIBRARY_VISIBILITY 174 #endif 175 176 #if __has_attribute(used) || __GNUC_PREREQ(3, 1) 177 #define LLVM_ATTRIBUTE_USED __attribute__((__used__)) 178 #else 179 #define LLVM_ATTRIBUTE_USED 180 #endif 181 182 // Some compilers warn about unused functions. When a function is sometimes 183 // used or not depending on build settings (e.g. a function only called from 184 // within "assert"), this attribute can be used to suppress such warnings. 185 // 186 // However, it shouldn't be used for unused *variables*, as those have a much 187 // more portable solution: 188 // (void)unused_var_name; 189 // Prefer cast-to-void wherever it is sufficient. 190 #if __has_attribute(unused) || __GNUC_PREREQ(3, 1) 191 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__)) 192 #else 193 #define LLVM_ATTRIBUTE_UNUSED 194 #endif 195 196 // FIXME: Provide this for PE/COFF targets. 197 #if (__has_attribute(weak) || __GNUC_PREREQ(4, 0)) && \ 198 (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(LLVM_ON_WIN32)) 199 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__)) 200 #else 201 #define LLVM_ATTRIBUTE_WEAK 202 #endif 203 204 // Prior to clang 3.2, clang did not accept any spelling of 205 // __has_attribute(const), so assume it is supported. 206 #if defined(__clang__) || defined(__GNUC__) 207 // aka 'CONST' but following LLVM Conventions. 208 #define LLVM_READNONE __attribute__((__const__)) 209 #else 210 #define LLVM_READNONE 211 #endif 212 213 #if __has_attribute(pure) || defined(__GNUC__) 214 // aka 'PURE' but following LLVM Conventions. 215 #define LLVM_READONLY __attribute__((__pure__)) 216 #else 217 #define LLVM_READONLY 218 #endif 219 220 #if __has_builtin(__builtin_expect) || __GNUC_PREREQ(4, 0) 221 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true) 222 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false) 223 #else 224 #define LLVM_LIKELY(EXPR) (EXPR) 225 #define LLVM_UNLIKELY(EXPR) (EXPR) 226 #endif 227 228 // C++ doesn't support 'extern template' of template specializations. GCC does, 229 // but requires __extension__ before it. In the header, use this: 230 // EXTERN_TEMPLATE_INSTANTIATION(class foo<bar>); 231 // in the .cpp file, use this: 232 // TEMPLATE_INSTANTIATION(class foo<bar>); 233 #ifdef __GNUC__ 234 #define EXTERN_TEMPLATE_INSTANTIATION(X) __extension__ extern template X 235 #define TEMPLATE_INSTANTIATION(X) template X 236 #else 237 #define EXTERN_TEMPLATE_INSTANTIATION(X) 238 #define TEMPLATE_INSTANTIATION(X) 239 #endif 240 241 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so, 242 /// mark a method "not for inlining". 243 #if __has_attribute(noinline) || __GNUC_PREREQ(3, 4) 244 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline)) 245 #elif defined(_MSC_VER) 246 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline) 247 #else 248 #define LLVM_ATTRIBUTE_NOINLINE 249 #endif 250 251 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do 252 /// so, mark a method "always inline" because it is performance sensitive. GCC 253 /// 3.4 supported this but is buggy in various cases and produces unimplemented 254 /// errors, just use it in GCC 4.0 and later. 255 #if __has_attribute(always_inline) || __GNUC_PREREQ(4, 0) 256 #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline __attribute__((always_inline)) 257 #elif defined(_MSC_VER) 258 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline 259 #else 260 #define LLVM_ATTRIBUTE_ALWAYS_INLINE 261 #endif 262 263 #ifdef __GNUC__ 264 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn)) 265 #elif defined(_MSC_VER) 266 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn) 267 #else 268 #define LLVM_ATTRIBUTE_NORETURN 269 #endif 270 271 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress 272 /// pedantic diagnostics. 273 #ifdef __GNUC__ 274 #define LLVM_EXTENSION __extension__ 275 #else 276 #define LLVM_EXTENSION 277 #endif 278 279 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message") 280 #if __has_feature(attribute_deprecated_with_message) 281 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 282 decl __attribute__((deprecated(message))) 283 #elif defined(__GNUC__) 284 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 285 decl __attribute__((deprecated)) 286 #elif defined(_MSC_VER) 287 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 288 __declspec(deprecated(message)) decl 289 #else 290 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 291 decl 292 #endif 293 294 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands 295 /// to an expression which states that it is undefined behavior for the 296 /// compiler to reach this point. Otherwise is not defined. 297 #if __has_builtin(__builtin_unreachable) || __GNUC_PREREQ(4, 5) 298 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable() 299 #elif defined(_MSC_VER) 300 # define LLVM_BUILTIN_UNREACHABLE __assume(false) 301 #endif 302 303 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression 304 /// which causes the program to exit abnormally. 305 #if __has_builtin(__builtin_trap) || __GNUC_PREREQ(4, 3) 306 # define LLVM_BUILTIN_TRAP __builtin_trap() 307 #else 308 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0 309 #endif 310 311 /// \macro LLVM_ASSUME_ALIGNED 312 /// \brief Returns a pointer with an assumed alignment. 313 #if __has_builtin(__builtin_assume_aligned) && __GNUC_PREREQ(4, 7) 314 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a) 315 #elif defined(LLVM_BUILTIN_UNREACHABLE) 316 // As of today, clang does not support __builtin_assume_aligned. 317 # define LLVM_ASSUME_ALIGNED(p, a) \ 318 (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p))) 319 #else 320 # define LLVM_ASSUME_ALIGNED(p, a) (p) 321 #endif 322 323 /// \macro LLVM_FUNCTION_NAME 324 /// \brief Expands to __func__ on compilers which support it. Otherwise, 325 /// expands to a compiler-dependent replacement. 326 #if defined(_MSC_VER) 327 # define LLVM_FUNCTION_NAME __FUNCTION__ 328 #else 329 # define LLVM_FUNCTION_NAME __func__ 330 #endif 331 332 #if defined(HAVE_SANITIZER_MSAN_INTERFACE_H) 333 # include <sanitizer/msan_interface.h> 334 #else 335 # define __msan_allocated_memory(p, size) 336 # define __msan_unpoison(p, size) 337 #endif 338 339 /// \macro LLVM_MEMORY_SANITIZER_BUILD 340 /// \brief Whether LLVM itself is built with MemorySanitizer instrumentation. 341 #if __has_feature(memory_sanitizer) 342 # define LLVM_MEMORY_SANITIZER_BUILD 1 343 #else 344 # define LLVM_MEMORY_SANITIZER_BUILD 0 345 #endif 346 347 /// \macro LLVM_ADDRESS_SANITIZER_BUILD 348 /// \brief Whether LLVM itself is built with AddressSanitizer instrumentation. 349 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__) 350 # define LLVM_ADDRESS_SANITIZER_BUILD 1 351 #else 352 # define LLVM_ADDRESS_SANITIZER_BUILD 0 353 #endif 354 355 /// \macro LLVM_IS_UNALIGNED_ACCESS_FAST 356 /// \brief Is unaligned memory access fast on the host machine. 357 /// 358 /// Don't specialize on alignment for platforms where unaligned memory accesses 359 /// generates the same code as aligned memory accesses for common types. 360 #if defined(_M_AMD64) || defined(_M_IX86) || defined(__amd64) || \ 361 defined(__amd64__) || defined(__x86_64) || defined(__x86_64__) || \ 362 defined(_X86_) || defined(__i386) || defined(__i386__) 363 # define LLVM_IS_UNALIGNED_ACCESS_FAST 1 364 #else 365 # define LLVM_IS_UNALIGNED_ACCESS_FAST 0 366 #endif 367 368 /// \macro LLVM_EXPLICIT 369 /// \brief Expands to explicit on compilers which support explicit conversion 370 /// operators. Otherwise expands to nothing. 371 #if (__has_feature(cxx_explicit_conversions) \ 372 || defined(__GXX_EXPERIMENTAL_CXX0X__)) 373 #define LLVM_EXPLICIT explicit 374 #else 375 #define LLVM_EXPLICIT 376 #endif 377 378 /// \macro LLVM_STATIC_ASSERT 379 /// \brief Expands to C/C++'s static_assert on compilers which support it. 380 #if __has_feature(cxx_static_assert) 381 # define LLVM_STATIC_ASSERT(expr, msg) static_assert(expr, msg) 382 #elif __has_feature(c_static_assert) 383 # define LLVM_STATIC_ASSERT(expr, msg) _Static_assert(expr, msg) 384 #else 385 # define LLVM_STATIC_ASSERT(expr, msg) 386 #endif 387 388 #endif 389
