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 #if defined(_MSC_VER) 21 #include <sal.h> 22 #endif 23 24 #ifndef __has_feature 25 # define __has_feature(x) 0 26 #endif 27 28 #ifndef __has_extension 29 # define __has_extension(x) 0 30 #endif 31 32 #ifndef __has_attribute 33 # define __has_attribute(x) 0 34 #endif 35 36 #ifndef __has_builtin 37 # define __has_builtin(x) 0 38 #endif 39 40 /// \macro LLVM_GNUC_PREREQ 41 /// \brief Extend the default __GNUC_PREREQ even if glibc's features.h isn't 42 /// available. 43 #ifndef LLVM_GNUC_PREREQ 44 # if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__) 45 # define LLVM_GNUC_PREREQ(maj, min, patch) \ 46 ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \ 47 ((maj) << 20) + ((min) << 10) + (patch)) 48 # elif defined(__GNUC__) && defined(__GNUC_MINOR__) 49 # define LLVM_GNUC_PREREQ(maj, min, patch) \ 50 ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10)) 51 # else 52 # define LLVM_GNUC_PREREQ(maj, min, patch) 0 53 # endif 54 #endif 55 56 /// \macro LLVM_MSC_PREREQ 57 /// \brief Is the compiler MSVC of at least the specified version? 58 /// The common \param version values to check for are: 59 /// * 1800: Microsoft Visual Studio 2013 / 12.0 60 /// * 1900: Microsoft Visual Studio 2015 / 14.0 61 #ifdef _MSC_VER 62 #define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version)) 63 64 // We require at least MSVC 2013. 65 #if !LLVM_MSC_PREREQ(1800) 66 #error LLVM requires at least MSVC 2013. 67 #endif 68 69 #else 70 #define LLVM_MSC_PREREQ(version) 0 71 #endif 72 73 #if !defined(_MSC_VER) || defined(__clang__) || LLVM_MSC_PREREQ(1900) 74 #define LLVM_NOEXCEPT noexcept 75 #else 76 #define LLVM_NOEXCEPT throw() 77 #endif 78 79 /// \brief Does the compiler support ref-qualifiers for *this? 80 /// 81 /// Sadly, this is separate from just rvalue reference support because GCC 82 /// and MSVC implemented this later than everything else. 83 #if __has_feature(cxx_rvalue_references) || LLVM_GNUC_PREREQ(4, 8, 1) 84 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1 85 #else 86 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0 87 #endif 88 89 /// Expands to '&' if ref-qualifiers for *this are supported. 90 /// 91 /// This can be used to provide lvalue/rvalue overrides of member functions. 92 /// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS 93 #if LLVM_HAS_RVALUE_REFERENCE_THIS 94 #define LLVM_LVALUE_FUNCTION & 95 #else 96 #define LLVM_LVALUE_FUNCTION 97 #endif 98 99 #if __has_feature(cxx_constexpr) || defined(__GXX_EXPERIMENTAL_CXX0X__) || LLVM_MSC_PREREQ(1900) 100 # define LLVM_CONSTEXPR constexpr 101 #else 102 # define LLVM_CONSTEXPR 103 #endif 104 105 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked 106 /// into a shared library, then the class should be private to the library and 107 /// not accessible from outside it. Can also be used to mark variables and 108 /// functions, making them private to any shared library they are linked into. 109 /// On PE/COFF targets, library visibility is the default, so this isn't needed. 110 #if (__has_attribute(visibility) || LLVM_GNUC_PREREQ(4, 0, 0)) && \ 111 !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(LLVM_ON_WIN32) 112 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden"))) 113 #else 114 #define LLVM_LIBRARY_VISIBILITY 115 #endif 116 117 #if __has_attribute(sentinel) || LLVM_GNUC_PREREQ(3, 0, 0) 118 #define LLVM_END_WITH_NULL __attribute__((sentinel)) 119 #else 120 #define LLVM_END_WITH_NULL 121 #endif 122 123 #if __has_attribute(used) || LLVM_GNUC_PREREQ(3, 1, 0) 124 #define LLVM_ATTRIBUTE_USED __attribute__((__used__)) 125 #else 126 #define LLVM_ATTRIBUTE_USED 127 #endif 128 129 #if __has_attribute(warn_unused_result) || LLVM_GNUC_PREREQ(3, 4, 0) 130 #define LLVM_ATTRIBUTE_UNUSED_RESULT __attribute__((__warn_unused_result__)) 131 #elif defined(_MSC_VER) 132 #define LLVM_ATTRIBUTE_UNUSED_RESULT _Check_return_ 133 #else 134 #define LLVM_ATTRIBUTE_UNUSED_RESULT 135 #endif 136 137 // Some compilers warn about unused functions. When a function is sometimes 138 // used or not depending on build settings (e.g. a function only called from 139 // within "assert"), this attribute can be used to suppress such warnings. 140 // 141 // However, it shouldn't be used for unused *variables*, as those have a much 142 // more portable solution: 143 // (void)unused_var_name; 144 // Prefer cast-to-void wherever it is sufficient. 145 #if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0) 146 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__)) 147 #else 148 #define LLVM_ATTRIBUTE_UNUSED 149 #endif 150 151 // FIXME: Provide this for PE/COFF targets. 152 #if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) && \ 153 (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(LLVM_ON_WIN32)) 154 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__)) 155 #else 156 #define LLVM_ATTRIBUTE_WEAK 157 #endif 158 159 // Prior to clang 3.2, clang did not accept any spelling of 160 // __has_attribute(const), so assume it is supported. 161 #if defined(__clang__) || defined(__GNUC__) 162 // aka 'CONST' but following LLVM Conventions. 163 #define LLVM_READNONE __attribute__((__const__)) 164 #else 165 #define LLVM_READNONE 166 #endif 167 168 #if __has_attribute(pure) || defined(__GNUC__) 169 // aka 'PURE' but following LLVM Conventions. 170 #define LLVM_READONLY __attribute__((__pure__)) 171 #else 172 #define LLVM_READONLY 173 #endif 174 175 #if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0) 176 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true) 177 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false) 178 #else 179 #define LLVM_LIKELY(EXPR) (EXPR) 180 #define LLVM_UNLIKELY(EXPR) (EXPR) 181 #endif 182 183 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so, 184 /// mark a method "not for inlining". 185 #if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0) 186 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline)) 187 #elif defined(_MSC_VER) 188 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline) 189 #else 190 #define LLVM_ATTRIBUTE_NOINLINE 191 #endif 192 193 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do 194 /// so, mark a method "always inline" because it is performance sensitive. GCC 195 /// 3.4 supported this but is buggy in various cases and produces unimplemented 196 /// errors, just use it in GCC 4.0 and later. 197 #if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0) 198 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline)) 199 #elif defined(_MSC_VER) 200 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline 201 #else 202 #define LLVM_ATTRIBUTE_ALWAYS_INLINE 203 #endif 204 205 #ifdef __GNUC__ 206 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn)) 207 #elif defined(_MSC_VER) 208 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn) 209 #else 210 #define LLVM_ATTRIBUTE_NORETURN 211 #endif 212 213 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0) 214 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull)) 215 #elif defined(_MSC_VER) 216 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_ 217 #else 218 #define LLVM_ATTRIBUTE_RETURNS_NONNULL 219 #endif 220 221 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a 222 /// pointer that does not alias any other valid pointer. 223 #ifdef __GNUC__ 224 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__)) 225 #elif defined(_MSC_VER) 226 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict) 227 #else 228 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS 229 #endif 230 231 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress 232 /// pedantic diagnostics. 233 #ifdef __GNUC__ 234 #define LLVM_EXTENSION __extension__ 235 #else 236 #define LLVM_EXTENSION 237 #endif 238 239 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message") 240 #if __has_feature(attribute_deprecated_with_message) 241 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 242 decl __attribute__((deprecated(message))) 243 #elif defined(__GNUC__) 244 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 245 decl __attribute__((deprecated)) 246 #elif defined(_MSC_VER) 247 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 248 __declspec(deprecated(message)) decl 249 #else 250 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ 251 decl 252 #endif 253 254 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands 255 /// to an expression which states that it is undefined behavior for the 256 /// compiler to reach this point. Otherwise is not defined. 257 #if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0) 258 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable() 259 #elif defined(_MSC_VER) 260 # define LLVM_BUILTIN_UNREACHABLE __assume(false) 261 #endif 262 263 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression 264 /// which causes the program to exit abnormally. 265 #if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0) 266 # define LLVM_BUILTIN_TRAP __builtin_trap() 267 #elif defined(_MSC_VER) 268 // The __debugbreak intrinsic is supported by MSVC, does not require forward 269 // declarations involving platform-specific typedefs (unlike RaiseException), 270 // results in a call to vectored exception handlers, and encodes to a short 271 // instruction that still causes the trapping behavior we want. 272 # define LLVM_BUILTIN_TRAP __debugbreak() 273 #else 274 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0 275 #endif 276 277 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to 278 /// an expression which causes the program to break while running 279 /// under a debugger. 280 #if __has_builtin(__builtin_debugtrap) 281 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap() 282 #elif defined(_MSC_VER) 283 // The __debugbreak intrinsic is supported by MSVC and breaks while 284 // running under the debugger, and also supports invoking a debugger 285 // when the OS is configured appropriately. 286 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak() 287 #else 288 // Just continue execution when built with compilers that have no 289 // support. This is a debugging aid and not intended to force the 290 // program to abort if encountered. 291 # define LLVM_BUILTIN_DEBUGTRAP 292 #endif 293 294 /// \macro LLVM_ASSUME_ALIGNED 295 /// \brief Returns a pointer with an assumed alignment. 296 #if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0) 297 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a) 298 #elif defined(LLVM_BUILTIN_UNREACHABLE) 299 // As of today, clang does not support __builtin_assume_aligned. 300 # define LLVM_ASSUME_ALIGNED(p, a) \ 301 (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p))) 302 #else 303 # define LLVM_ASSUME_ALIGNED(p, a) (p) 304 #endif 305 306 /// \macro LLVM_ALIGNAS 307 /// \brief Used to specify a minimum alignment for a structure or variable. The 308 /// alignment must be a constant integer. Use LLVM_PTR_SIZE to compute 309 /// alignments in terms of the size of a pointer. 310 /// 311 /// Note that __declspec(align) has special quirks, it's not legal to pass a 312 /// structure with __declspec(align) as a formal parameter. 313 #ifdef _MSC_VER 314 # define LLVM_ALIGNAS(x) __declspec(align(x)) 315 #elif __GNUC__ && !__has_feature(cxx_alignas) && !LLVM_GNUC_PREREQ(4, 8, 0) 316 # define LLVM_ALIGNAS(x) __attribute__((aligned(x))) 317 #else 318 # define LLVM_ALIGNAS(x) alignas(x) 319 #endif 320 321 /// \macro LLVM_PACKED 322 /// \brief Used to specify a packed structure. 323 /// LLVM_PACKED( 324 /// struct A { 325 /// int i; 326 /// int j; 327 /// int k; 328 /// long long l; 329 /// }); 330 /// 331 /// LLVM_PACKED_START 332 /// struct B { 333 /// int i; 334 /// int j; 335 /// int k; 336 /// long long l; 337 /// }; 338 /// LLVM_PACKED_END 339 #ifdef _MSC_VER 340 # define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop)) 341 # define LLVM_PACKED_START __pragma(pack(push, 1)) 342 # define LLVM_PACKED_END __pragma(pack(pop)) 343 #else 344 # define LLVM_PACKED(d) d __attribute__((packed)) 345 # define LLVM_PACKED_START _Pragma("pack(push, 1)") 346 # define LLVM_PACKED_END _Pragma("pack(pop)") 347 #endif 348 349 /// \macro LLVM_PTR_SIZE 350 /// \brief A constant integer equivalent to the value of sizeof(void*). 351 /// Generally used in combination with LLVM_ALIGNAS or when doing computation in 352 /// the preprocessor. 353 #ifdef __SIZEOF_POINTER__ 354 # define LLVM_PTR_SIZE __SIZEOF_POINTER__ 355 #elif defined(_WIN64) 356 # define LLVM_PTR_SIZE 8 357 #elif defined(_WIN32) 358 # define LLVM_PTR_SIZE 4 359 #elif defined(_MSC_VER) 360 # error "could not determine LLVM_PTR_SIZE as a constant int for MSVC" 361 #else 362 # define LLVM_PTR_SIZE sizeof(void *) 363 #endif 364 365 /// \macro LLVM_FUNCTION_NAME 366 /// \brief Expands to __func__ on compilers which support it. Otherwise, 367 /// expands to a compiler-dependent replacement. 368 #if defined(_MSC_VER) 369 # define LLVM_FUNCTION_NAME __FUNCTION__ 370 #else 371 # define LLVM_FUNCTION_NAME __func__ 372 #endif 373 374 /// \macro LLVM_MEMORY_SANITIZER_BUILD 375 /// \brief Whether LLVM itself is built with MemorySanitizer instrumentation. 376 #if __has_feature(memory_sanitizer) 377 # define LLVM_MEMORY_SANITIZER_BUILD 1 378 # include <sanitizer/msan_interface.h> 379 #else 380 # define LLVM_MEMORY_SANITIZER_BUILD 0 381 # define __msan_allocated_memory(p, size) 382 # define __msan_unpoison(p, size) 383 #endif 384 385 /// \macro LLVM_ADDRESS_SANITIZER_BUILD 386 /// \brief Whether LLVM itself is built with AddressSanitizer instrumentation. 387 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__) 388 # define LLVM_ADDRESS_SANITIZER_BUILD 1 389 # include <sanitizer/asan_interface.h> 390 #else 391 # define LLVM_ADDRESS_SANITIZER_BUILD 0 392 # define __asan_poison_memory_region(p, size) 393 # define __asan_unpoison_memory_region(p, size) 394 #endif 395 396 /// \macro LLVM_THREAD_SANITIZER_BUILD 397 /// \brief Whether LLVM itself is built with ThreadSanitizer instrumentation. 398 #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__) 399 # define LLVM_THREAD_SANITIZER_BUILD 1 400 #else 401 # define LLVM_THREAD_SANITIZER_BUILD 0 402 #endif 403 404 #if LLVM_THREAD_SANITIZER_BUILD 405 // Thread Sanitizer is a tool that finds races in code. 406 // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations . 407 // tsan detects these exact functions by name. 408 extern "C" { 409 void AnnotateHappensAfter(const char *file, int line, const volatile void *cv); 410 void AnnotateHappensBefore(const char *file, int line, const volatile void *cv); 411 void AnnotateIgnoreWritesBegin(const char *file, int line); 412 void AnnotateIgnoreWritesEnd(const char *file, int line); 413 } 414 415 // This marker is used to define a happens-before arc. The race detector will 416 // infer an arc from the begin to the end when they share the same pointer 417 // argument. 418 # define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv) 419 420 // This marker defines the destination of a happens-before arc. 421 # define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv) 422 423 // Ignore any races on writes between here and the next TsanIgnoreWritesEnd. 424 # define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__) 425 426 // Resume checking for racy writes. 427 # define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__) 428 #else 429 # define TsanHappensBefore(cv) 430 # define TsanHappensAfter(cv) 431 # define TsanIgnoreWritesBegin() 432 # define TsanIgnoreWritesEnd() 433 #endif 434 435 /// \macro LLVM_NO_SANITIZE 436 /// \brief Disable a particular sanitizer for a function. 437 #if __has_attribute(no_sanitize) 438 #define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND))) 439 #else 440 #define LLVM_NO_SANITIZE(KIND) 441 #endif 442 443 /// \brief Mark debug helper function definitions like dump() that should not be 444 /// stripped from debug builds. 445 // FIXME: Move this to a private config.h as it's not usable in public headers. 446 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 447 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED 448 #else 449 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE 450 #endif 451 452 /// \macro LLVM_THREAD_LOCAL 453 /// \brief A thread-local storage specifier which can be used with globals, 454 /// extern globals, and static globals. 455 /// 456 /// This is essentially an extremely restricted analog to C++11's thread_local 457 /// support, and uses that when available. However, it falls back on 458 /// platform-specific or vendor-provided extensions when necessary. These 459 /// extensions don't support many of the C++11 thread_local's features. You 460 /// should only use this for PODs that you can statically initialize to 461 /// some constant value. In almost all circumstances this is most appropriate 462 /// for use with a pointer, integer, or small aggregation of pointers and 463 /// integers. 464 #if LLVM_ENABLE_THREADS 465 #if __has_feature(cxx_thread_local) 466 #define LLVM_THREAD_LOCAL thread_local 467 #elif defined(_MSC_VER) 468 // MSVC supports this with a __declspec. 469 #define LLVM_THREAD_LOCAL __declspec(thread) 470 #else 471 // Clang, GCC, and other compatible compilers used __thread prior to C++11 and 472 // we only need the restricted functionality that provides. 473 #define LLVM_THREAD_LOCAL __thread 474 #endif 475 #else // !LLVM_ENABLE_THREADS 476 // If threading is disabled entirely, this compiles to nothing and you get 477 // a normal global variable. 478 #define LLVM_THREAD_LOCAL 479 #endif 480 481 #endif 482