include/llvm/Support/Compiler.h

   1 //===-- llvm/Support/Compiler.h - Compiler abstraction support --*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file defines several macros, based on the current compiler.  This allows
  10 // use of compiler-specific features in a way that remains portable. This header
  11 // can be included from either C or C++.
  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 #ifdef __cplusplus
  21 #include <new>
  22 #endif
  23 #include <stddef.h>
  24
  25 #if defined(_MSC_VER)
  26 #include <sal.h>
  27 #endif
  28
  29 #ifndef __has_feature
  30 # define __has_feature(x) 0
  31 #endif
  32
  33 #ifndef __has_extension
  34 # define __has_extension(x) 0
  35 #endif
  36
  37 #ifndef __has_attribute
  38 # define __has_attribute(x) 0
  39 #endif
  40
  41 #ifndef __has_builtin
  42 # define __has_builtin(x) 0
  43 #endif
  44
  45 // Only use __has_cpp_attribute in C++ mode. GCC defines __has_cpp_attribute in
  46 // C mode, but the :: in __has_cpp_attribute(scoped::attribute) is invalid.
  47 #ifndef LLVM_HAS_CPP_ATTRIBUTE
  48 #if defined(__cplusplus) && defined(__has_cpp_attribute)
  49 # define LLVM_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
  50 #else
  51 # define LLVM_HAS_CPP_ATTRIBUTE(x) 0
  52 #endif
  53 #endif
  54
  55 /// \macro LLVM_GNUC_PREREQ
  56 /// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
  57 /// available.
  58 #ifndef LLVM_GNUC_PREREQ
  59 # if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
  60 #  define LLVM_GNUC_PREREQ(maj, min, patch) \
  61     ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
  62      ((maj) << 20) + ((min) << 10) + (patch))
  63 # elif defined(__GNUC__) && defined(__GNUC_MINOR__)
  64 #  define LLVM_GNUC_PREREQ(maj, min, patch) \
  65     ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
  66 # else
  67 #  define LLVM_GNUC_PREREQ(maj, min, patch) 0
  68 # endif
  69 #endif
  70
  71 /// \macro LLVM_MSC_PREREQ
  72 /// Is the compiler MSVC of at least the specified version?
  73 /// The common \param version values to check for are:
  74 /// * 1910: VS2017, version 15.1 & 15.2
  75 /// * 1911: VS2017, version 15.3 & 15.4
  76 /// * 1912: VS2017, version 15.5
  77 /// * 1913: VS2017, version 15.6
  78 /// * 1914: VS2017, version 15.7
  79 /// * 1915: VS2017, version 15.8
  80 /// * 1916: VS2017, version 15.9
  81 /// * 1920: VS2019, version 16.0
  82 /// * 1921: VS2019, version 16.1
  83 #ifdef _MSC_VER
  84 #define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version))
  85
  86 // We require at least MSVC 2017.
  87 #if !LLVM_MSC_PREREQ(1910)
  88 #error LLVM requires at least MSVC 2017.
  89 #endif
  90
  91 #else
  92 #define LLVM_MSC_PREREQ(version) 0
  93 #endif
  94
  95 /// Does the compiler support ref-qualifiers for *this?
  96 ///
  97 /// Sadly, this is separate from just rvalue reference support because GCC
  98 /// and MSVC implemented this later than everything else.
  99 #if __has_feature(cxx_rvalue_references) || LLVM_GNUC_PREREQ(4, 8, 1)
 100 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1
 101 #else
 102 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0
 103 #endif
 104
 105 /// Expands to '&' if ref-qualifiers for *this are supported.
 106 ///
 107 /// This can be used to provide lvalue/rvalue overrides of member functions.
 108 /// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
 109 #if LLVM_HAS_RVALUE_REFERENCE_THIS
 110 #define LLVM_LVALUE_FUNCTION &
 111 #else
 112 #define LLVM_LVALUE_FUNCTION
 113 #endif
 114
 115 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
 116 /// into a shared library, then the class should be private to the library and
 117 /// not accessible from outside it.  Can also be used to mark variables and
 118 /// functions, making them private to any shared library they are linked into.
 119 /// On PE/COFF targets, library visibility is the default, so this isn't needed.
 120 #if (__has_attribute(visibility) || LLVM_GNUC_PREREQ(4, 0, 0)) &&              \
 121     !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32)
 122 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
 123 #else
 124 #define LLVM_LIBRARY_VISIBILITY
 125 #endif
 126
 127 #if defined(__GNUC__)
 128 #define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
 129 #else
 130 #define LLVM_PREFETCH(addr, rw, locality)
 131 #endif
 132
 133 #if __has_attribute(used) || LLVM_GNUC_PREREQ(3, 1, 0)
 134 #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
 135 #else
 136 #define LLVM_ATTRIBUTE_USED
 137 #endif
 138
 139 /// LLVM_NODISCARD - Warn if a type or return value is discarded.
 140 #if __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
 141 #define LLVM_NODISCARD [[nodiscard]]
 142 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::warn_unused_result)
 143 #define LLVM_NODISCARD [[clang::warn_unused_result]]
 144 #else
 145 #define LLVM_NODISCARD
 146 #endif
 147
 148 // Indicate that a non-static, non-const C++ member function reinitializes
 149 // the entire object to a known state, independent of the previous state of
 150 // the object.
 151 //
 152 // The clang-tidy check bugprone-use-after-move recognizes this attribute as a
 153 // marker that a moved-from object has left the indeterminate state and can be
 154 // reused.
 155 #if LLVM_HAS_CPP_ATTRIBUTE(clang::reinitializes)
 156 #define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
 157 #else
 158 #define LLVM_ATTRIBUTE_REINITIALIZES
 159 #endif
 160
 161 // Some compilers warn about unused functions. When a function is sometimes
 162 // used or not depending on build settings (e.g. a function only called from
 163 // within "assert"), this attribute can be used to suppress such warnings.
 164 //
 165 // However, it shouldn't be used for unused *variables*, as those have a much
 166 // more portable solution:
 167 //   (void)unused_var_name;
 168 // Prefer cast-to-void wherever it is sufficient.
 169 #if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0)
 170 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
 171 #else
 172 #define LLVM_ATTRIBUTE_UNUSED
 173 #endif
 174
 175 // FIXME: Provide this for PE/COFF targets.
 176 #if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) &&                    \
 177     (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32))
 178 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
 179 #else
 180 #define LLVM_ATTRIBUTE_WEAK
 181 #endif
 182
 183 // Prior to clang 3.2, clang did not accept any spelling of
 184 // __has_attribute(const), so assume it is supported.
 185 #if defined(__clang__) || defined(__GNUC__)
 186 // aka 'CONST' but following LLVM Conventions.
 187 #define LLVM_READNONE __attribute__((__const__))
 188 #else
 189 #define LLVM_READNONE
 190 #endif
 191
 192 #if __has_attribute(pure) || defined(__GNUC__)
 193 // aka 'PURE' but following LLVM Conventions.
 194 #define LLVM_READONLY __attribute__((__pure__))
 195 #else
 196 #define LLVM_READONLY
 197 #endif
 198
 199 #if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0)
 200 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
 201 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
 202 #else
 203 #define LLVM_LIKELY(EXPR) (EXPR)
 204 #define LLVM_UNLIKELY(EXPR) (EXPR)
 205 #endif
 206
 207 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
 208 /// mark a method "not for inlining".
 209 #if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0)
 210 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
 211 #elif defined(_MSC_VER)
 212 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
 213 #else
 214 #define LLVM_ATTRIBUTE_NOINLINE
 215 #endif
 216
 217 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
 218 /// so, mark a method "always inline" because it is performance sensitive. GCC
 219 /// 3.4 supported this but is buggy in various cases and produces unimplemented
 220 /// errors, just use it in GCC 4.0 and later.
 221 #if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0)
 222 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
 223 #elif defined(_MSC_VER)
 224 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
 225 #else
 226 #define LLVM_ATTRIBUTE_ALWAYS_INLINE
 227 #endif
 228
 229 #ifdef __GNUC__
 230 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn))
 231 #elif defined(_MSC_VER)
 232 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn)
 233 #else
 234 #define LLVM_ATTRIBUTE_NORETURN
 235 #endif
 236
 237 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0)
 238 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
 239 #elif defined(_MSC_VER)
 240 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
 241 #else
 242 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
 243 #endif
 244
 245 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
 246 /// pointer that does not alias any other valid pointer.
 247 #ifdef __GNUC__
 248 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
 249 #elif defined(_MSC_VER)
 250 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
 251 #else
 252 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS
 253 #endif
 254
 255 /// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
 256 #if __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(fallthrough)
 257 #define LLVM_FALLTHROUGH [[fallthrough]]
 258 #elif LLVM_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
 259 #define LLVM_FALLTHROUGH [[gnu::fallthrough]]
 260 #elif __has_attribute(fallthrough)
 261 #define LLVM_FALLTHROUGH __attribute__((fallthrough))
 262 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::fallthrough)
 263 #define LLVM_FALLTHROUGH [[clang::fallthrough]]
 264 #else
 265 #define LLVM_FALLTHROUGH
 266 #endif
 267
 268 /// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
 269 /// they are constant initialized.
 270 #if LLVM_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization)
 271 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION                                   \
 272   [[clang::require_constant_initialization]]
 273 #else
 274 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION
 275 #endif
 276
 277 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
 278 /// pedantic diagnostics.
 279 #ifdef __GNUC__
 280 #define LLVM_EXTENSION __extension__
 281 #else
 282 #define LLVM_EXTENSION
 283 #endif
 284
 285 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message")
 286 #if __has_feature(attribute_deprecated_with_message)
 287 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
 288   decl __attribute__((deprecated(message)))
 289 #elif defined(__GNUC__)
 290 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
 291   decl __attribute__((deprecated))
 292 #elif defined(_MSC_VER)
 293 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
 294   __declspec(deprecated(message)) decl
 295 #else
 296 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
 297   decl
 298 #endif
 299
 300 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
 301 /// to an expression which states that it is undefined behavior for the
 302 /// compiler to reach this point.  Otherwise is not defined.
 303 #if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0)
 304 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
 305 #elif defined(_MSC_VER)
 306 # define LLVM_BUILTIN_UNREACHABLE __assume(false)
 307 #endif
 308
 309 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
 310 /// which causes the program to exit abnormally.
 311 #if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0)
 312 # define LLVM_BUILTIN_TRAP __builtin_trap()
 313 #elif defined(_MSC_VER)
 314 // The __debugbreak intrinsic is supported by MSVC, does not require forward
 315 // declarations involving platform-specific typedefs (unlike RaiseException),
 316 // results in a call to vectored exception handlers, and encodes to a short
 317 // instruction that still causes the trapping behavior we want.
 318 # define LLVM_BUILTIN_TRAP __debugbreak()
 319 #else
 320 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
 321 #endif
 322
 323 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
 324 /// an expression which causes the program to break while running
 325 /// under a debugger.
 326 #if __has_builtin(__builtin_debugtrap)
 327 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
 328 #elif defined(_MSC_VER)
 329 // The __debugbreak intrinsic is supported by MSVC and breaks while
 330 // running under the debugger, and also supports invoking a debugger
 331 // when the OS is configured appropriately.
 332 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
 333 #else
 334 // Just continue execution when built with compilers that have no
 335 // support. This is a debugging aid and not intended to force the
 336 // program to abort if encountered.
 337 # define LLVM_BUILTIN_DEBUGTRAP
 338 #endif
 339
 340 /// \macro LLVM_ASSUME_ALIGNED
 341 /// Returns a pointer with an assumed alignment.
 342 #if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0)
 343 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
 344 #elif defined(LLVM_BUILTIN_UNREACHABLE)
 345 // As of today, clang does not support __builtin_assume_aligned.
 346 # define LLVM_ASSUME_ALIGNED(p, a) \
 347            (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
 348 #else
 349 # define LLVM_ASSUME_ALIGNED(p, a) (p)
 350 #endif
 351
 352 /// \macro LLVM_PACKED
 353 /// Used to specify a packed structure.
 354 /// LLVM_PACKED(
 355 ///    struct A {
 356 ///      int i;
 357 ///      int j;
 358 ///      int k;
 359 ///      long long l;
 360 ///   });
 361 ///
 362 /// LLVM_PACKED_START
 363 /// struct B {
 364 ///   int i;
 365 ///   int j;
 366 ///   int k;
 367 ///   long long l;
 368 /// };
 369 /// LLVM_PACKED_END
 370 #ifdef _MSC_VER
 371 # define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
 372 # define LLVM_PACKED_START __pragma(pack(push, 1))
 373 # define LLVM_PACKED_END   __pragma(pack(pop))
 374 #else
 375 # define LLVM_PACKED(d) d __attribute__((packed))
 376 # define LLVM_PACKED_START _Pragma("pack(push, 1)")
 377 # define LLVM_PACKED_END   _Pragma("pack(pop)")
 378 #endif
 379
 380 /// \macro LLVM_PTR_SIZE
 381 /// A constant integer equivalent to the value of sizeof(void*).
 382 /// Generally used in combination with alignas or when doing computation in the
 383 /// preprocessor.
 384 #ifdef __SIZEOF_POINTER__
 385 # define LLVM_PTR_SIZE __SIZEOF_POINTER__
 386 #elif defined(_WIN64)
 387 # define LLVM_PTR_SIZE 8
 388 #elif defined(_WIN32)
 389 # define LLVM_PTR_SIZE 4
 390 #elif defined(_MSC_VER)
 391 # error "could not determine LLVM_PTR_SIZE as a constant int for MSVC"
 392 #else
 393 # define LLVM_PTR_SIZE sizeof(void *)
 394 #endif
 395
 396 /// \macro LLVM_MEMORY_SANITIZER_BUILD
 397 /// Whether LLVM itself is built with MemorySanitizer instrumentation.
 398 #if __has_feature(memory_sanitizer)
 399 # define LLVM_MEMORY_SANITIZER_BUILD 1
 400 # include <sanitizer/msan_interface.h>
 401 #else
 402 # define LLVM_MEMORY_SANITIZER_BUILD 0
 403 # define __msan_allocated_memory(p, size)
 404 # define __msan_unpoison(p, size)
 405 #endif
 406
 407 /// \macro LLVM_ADDRESS_SANITIZER_BUILD
 408 /// Whether LLVM itself is built with AddressSanitizer instrumentation.
 409 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
 410 # define LLVM_ADDRESS_SANITIZER_BUILD 1
 411 # include <sanitizer/asan_interface.h>
 412 #else
 413 # define LLVM_ADDRESS_SANITIZER_BUILD 0
 414 # define __asan_poison_memory_region(p, size)
 415 # define __asan_unpoison_memory_region(p, size)
 416 #endif
 417
 418 /// \macro LLVM_THREAD_SANITIZER_BUILD
 419 /// Whether LLVM itself is built with ThreadSanitizer instrumentation.
 420 #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
 421 # define LLVM_THREAD_SANITIZER_BUILD 1
 422 #else
 423 # define LLVM_THREAD_SANITIZER_BUILD 0
 424 #endif
 425
 426 #if LLVM_THREAD_SANITIZER_BUILD
 427 // Thread Sanitizer is a tool that finds races in code.
 428 // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
 429 // tsan detects these exact functions by name.
 430 #ifdef __cplusplus
 431 extern "C" {
 432 #endif
 433 void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
 434 void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
 435 void AnnotateIgnoreWritesBegin(const char *file, int line);
 436 void AnnotateIgnoreWritesEnd(const char *file, int line);
 437 #ifdef __cplusplus
 438 }
 439 #endif
 440
 441 // This marker is used to define a happens-before arc. The race detector will
 442 // infer an arc from the begin to the end when they share the same pointer
 443 // argument.
 444 # define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)
 445
 446 // This marker defines the destination of a happens-before arc.
 447 # define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)
 448
 449 // Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
 450 # define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
 451
 452 // Resume checking for racy writes.
 453 # define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
 454 #else
 455 # define TsanHappensBefore(cv)
 456 # define TsanHappensAfter(cv)
 457 # define TsanIgnoreWritesBegin()
 458 # define TsanIgnoreWritesEnd()
 459 #endif
 460
 461 /// \macro LLVM_NO_SANITIZE
 462 /// Disable a particular sanitizer for a function.
 463 #if __has_attribute(no_sanitize)
 464 #define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
 465 #else
 466 #define LLVM_NO_SANITIZE(KIND)
 467 #endif
 468
 469 /// Mark debug helper function definitions like dump() that should not be
 470 /// stripped from debug builds.
 471 /// Note that you should also surround dump() functions with
 472 /// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always
 473 /// get stripped in release builds.
 474 // FIXME: Move this to a private config.h as it's not usable in public headers.
 475 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 476 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
 477 #else
 478 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE
 479 #endif
 480
 481 /// \macro LLVM_PRETTY_FUNCTION
 482 /// Gets a user-friendly looking function signature for the current scope
 483 /// using the best available method on each platform.  The exact format of the
 484 /// resulting string is implementation specific and non-portable, so this should
 485 /// only be used, for example, for logging or diagnostics.
 486 #if defined(_MSC_VER)
 487 #define LLVM_PRETTY_FUNCTION __FUNCSIG__
 488 #elif defined(__GNUC__) || defined(__clang__)
 489 #define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__
 490 #else
 491 #define LLVM_PRETTY_FUNCTION __func__
 492 #endif
 493
 494 /// \macro LLVM_THREAD_LOCAL
 495 /// A thread-local storage specifier which can be used with globals,
 496 /// extern globals, and static globals.
 497 ///
 498 /// This is essentially an extremely restricted analog to C++11's thread_local
 499 /// support, and uses that when available. However, it falls back on
 500 /// platform-specific or vendor-provided extensions when necessary. These
 501 /// extensions don't support many of the C++11 thread_local's features. You
 502 /// should only use this for PODs that you can statically initialize to
 503 /// some constant value. In almost all circumstances this is most appropriate
 504 /// for use with a pointer, integer, or small aggregation of pointers and
 505 /// integers.
 506 #if LLVM_ENABLE_THREADS
 507 #if __has_feature(cxx_thread_local)
 508 #define LLVM_THREAD_LOCAL thread_local
 509 #elif defined(_MSC_VER)
 510 // MSVC supports this with a __declspec.
 511 #define LLVM_THREAD_LOCAL __declspec(thread)
 512 #else
 513 // Clang, GCC, and other compatible compilers used __thread prior to C++11 and
 514 // we only need the restricted functionality that provides.
 515 #define LLVM_THREAD_LOCAL __thread
 516 #endif
 517 #else // !LLVM_ENABLE_THREADS
 518 // If threading is disabled entirely, this compiles to nothing and you get
 519 // a normal global variable.
 520 #define LLVM_THREAD_LOCAL
 521 #endif
 522
 523 /// \macro LLVM_ENABLE_EXCEPTIONS
 524 /// Whether LLVM is built with exception support.
 525 #if __has_feature(cxx_exceptions)
 526 #define LLVM_ENABLE_EXCEPTIONS 1
 527 #elif defined(__GNUC__) && defined(__EXCEPTIONS)
 528 #define LLVM_ENABLE_EXCEPTIONS 1
 529 #elif defined(_MSC_VER) && defined(_CPPUNWIND)
 530 #define LLVM_ENABLE_EXCEPTIONS 1
 531 #endif
 532
 533 #ifdef __cplusplus
 534 namespace llvm {
 535
 536 /// Allocate a buffer of memory with the given size and alignment.
 537 ///
 538 /// When the compiler supports aligned operator new, this will use it to to
 539 /// handle even over-aligned allocations.
 540 ///
 541 /// However, this doesn't make any attempt to leverage the fancier techniques
 542 /// like posix_memalign due to portability. It is mostly intended to allow
 543 /// compatibility with platforms that, after aligned allocation was added, use
 544 /// reduced default alignment.
 545 inline void *allocate_buffer(size_t Size, size_t Alignment) {
 546   return ::operator new(Size
 547 #ifdef __cpp_aligned_new
 548                         ,
 549                         std::align_val_t(Alignment)
 550 #endif
 551   );
 552 }
 553
 554 /// Deallocate a buffer of memory with the given size and alignment.
 555 ///
 556 /// If supported, this will used the sized delete operator. Also if supported,
 557 /// this will pass the alignment to the delete operator.
 558 ///
 559 /// The pointer must have been allocated with the corresponding new operator,
 560 /// most likely using the above helper.
 561 inline void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment) {
 562   ::operator delete(Ptr
 563 #ifdef __cpp_sized_deallocation
 564                     ,
 565                     Size
 566 #endif
 567 #ifdef __cpp_aligned_new
 568                     ,
 569                     std::align_val_t(Alignment)
 570 #endif
 571   );
 572 }
 573
 574 } // End namespace llvm
 575
 576 #endif // __cplusplus
 577 #endif