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