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 #include <stddef.h>
21 
22 #if defined(_MSC_VER)
23 #include <sal.h>
24 #endif
25 
26 #ifndef __has_feature
27 # define __has_feature(x) 0
28 #endif
29 
30 #ifndef __has_extension
31 # define __has_extension(x) 0
32 #endif
33 
34 #ifndef __has_attribute
35 # define __has_attribute(x) 0
36 #endif
37 
38 #ifndef __has_builtin
39 # define __has_builtin(x) 0
40 #endif
41 
42 // Only use __has_cpp_attribute in C++ mode. GCC defines __has_cpp_attribute in
43 // C mode, but the :: in __has_cpp_attribute(scoped::attribute) is invalid.
44 #ifndef LLVM_HAS_CPP_ATTRIBUTE
45 #if defined(__cplusplus) && defined(__has_cpp_attribute)
46 # define LLVM_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
47 #else
48 # define LLVM_HAS_CPP_ATTRIBUTE(x) 0
49 #endif
50 #endif
51 
52 /// \macro LLVM_GNUC_PREREQ
53 /// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
54 /// available.
55 #ifndef LLVM_GNUC_PREREQ
56 # if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
57 #  define LLVM_GNUC_PREREQ(maj, min, patch) \
58     ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
59      ((maj) << 20) + ((min) << 10) + (patch))
60 # elif defined(__GNUC__) && defined(__GNUC_MINOR__)
61 #  define LLVM_GNUC_PREREQ(maj, min, patch) \
62     ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
63 # else
64 #  define LLVM_GNUC_PREREQ(maj, min, patch) 0
65 # endif
66 #endif
67 
68 /// \macro LLVM_MSC_PREREQ
69 /// Is the compiler MSVC of at least the specified version?
70 /// The common \param version values to check for are:
71 /// * 1910: VS2017, version 15.1 & 15.2
72 /// * 1911: VS2017, version 15.3 & 15.4
73 /// * 1912: VS2017, version 15.5
74 /// * 1913: VS2017, version 15.6
75 /// * 1914: VS2017, version 15.7
76 /// * 1915: VS2017, version 15.8
77 /// * 1916: VS2017, version 15.9
78 /// * 1920: VS2019, version 16.0
79 /// * 1921: VS2019, version 16.1
80 /// * 1922: VS2019, version 16.2
81 /// * 1923: VS2019, version 16.3
82 /// * 1924: VS2019, version 16.4
83 /// * 1925: VS2019, version 16.5
84 /// * 1926: VS2019, version 16.6
85 /// * 1927: VS2019, version 16.7
86 /// * 1928: VS2019, version 16.8 + 16.9
87 /// * 1929: VS2019, version 16.10 + 16.11
88 /// * 1930: VS2022, version 17.0
89 #ifdef _MSC_VER
90 #define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version))
91 
92 // We require at least VS 2019.
93 #if !LLVM_MSC_PREREQ(1920)
94 #error LLVM requires at least VS 2019.
95 #endif
96 
97 #else
98 #define LLVM_MSC_PREREQ(version) 0
99 #endif
100 
101 /// Does the compiler support ref-qualifiers for *this?
102 ///
103 /// Sadly, this is separate from just rvalue reference support because GCC
104 /// and MSVC implemented this later than everything else. This appears to be
105 /// corrected in MSVC 2019 but not MSVC 2017.
106 /// FIXME: Remove LLVM_HAS_RVALUE_REFERENCE_THIS macro
107 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1
108 
109 /// Expands to '&' if ref-qualifiers for *this are supported.
110 ///
111 /// This can be used to provide lvalue/rvalue overrides of member functions.
112 /// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
113 #if LLVM_HAS_RVALUE_REFERENCE_THIS
114 #define LLVM_LVALUE_FUNCTION &
115 #else
116 #define LLVM_LVALUE_FUNCTION
117 #endif
118 
119 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
120 /// into a shared library, then the class should be private to the library and
121 /// not accessible from outside it.  Can also be used to mark variables and
122 /// functions, making them private to any shared library they are linked into.
123 /// On PE/COFF targets, library visibility is the default, so this isn't needed.
124 ///
125 /// LLVM_EXTERNAL_VISIBILITY - classes, functions, and variables marked with
126 /// this attribute will be made public and visible outside of any shared library
127 /// they are linked in to.
128 #if __has_attribute(visibility) && !defined(__MINGW32__) &&                    \
129     !defined(__CYGWIN__) && !defined(_WIN32)
130 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
131 #if defined(LLVM_BUILD_LLVM_DYLIB) || defined(LLVM_BUILD_SHARED_LIBS)
132 #define LLVM_EXTERNAL_VISIBILITY __attribute__((visibility("default")))
133 #else
134 #define LLVM_EXTERNAL_VISIBILITY
135 #endif
136 #else
137 #define LLVM_LIBRARY_VISIBILITY
138 #define LLVM_EXTERNAL_VISIBILITY
139 #endif
140 
141 #if defined(__GNUC__)
142 #define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
143 #else
144 #define LLVM_PREFETCH(addr, rw, locality)
145 #endif
146 
147 #if __has_attribute(used)
148 #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
149 #else
150 #define LLVM_ATTRIBUTE_USED
151 #endif
152 
153 /// LLVM_NODISCARD - Warn if a type or return value is discarded.
154 
155 // Use the 'nodiscard' attribute in C++17 or newer mode.
156 #if defined(__cplusplus) && __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
157 #define LLVM_NODISCARD [[nodiscard]]
158 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::warn_unused_result)
159 #define LLVM_NODISCARD [[clang::warn_unused_result]]
160 // Clang in C++14 mode claims that it has the 'nodiscard' attribute, but also
161 // warns in the pedantic mode that 'nodiscard' is a C++17 extension (PR33518).
162 // Use the 'nodiscard' attribute in C++14 mode only with GCC.
163 // TODO: remove this workaround when PR33518 is resolved.
164 #elif defined(__GNUC__) && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
165 #define LLVM_NODISCARD [[nodiscard]]
166 #else
167 #define LLVM_NODISCARD
168 #endif
169 
170 // Indicate that a non-static, non-const C++ member function reinitializes
171 // the entire object to a known state, independent of the previous state of
172 // the object.
173 //
174 // The clang-tidy check bugprone-use-after-move recognizes this attribute as a
175 // marker that a moved-from object has left the indeterminate state and can be
176 // reused.
177 #if LLVM_HAS_CPP_ATTRIBUTE(clang::reinitializes)
178 #define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
179 #else
180 #define LLVM_ATTRIBUTE_REINITIALIZES
181 #endif
182 
183 // Some compilers warn about unused functions. When a function is sometimes
184 // used or not depending on build settings (e.g. a function only called from
185 // within "assert"), this attribute can be used to suppress such warnings.
186 //
187 // However, it shouldn't be used for unused *variables*, as those have a much
188 // more portable solution:
189 //   (void)unused_var_name;
190 // Prefer cast-to-void wherever it is sufficient.
191 #if __has_attribute(unused)
192 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
193 #else
194 #define LLVM_ATTRIBUTE_UNUSED
195 #endif
196 
197 // FIXME: Provide this for PE/COFF targets.
198 #if __has_attribute(weak) && !defined(__MINGW32__) && !defined(__CYGWIN__) &&  \
199     !defined(_WIN32)
200 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
201 #else
202 #define LLVM_ATTRIBUTE_WEAK
203 #endif
204 
205 // Prior to clang 3.2, clang did not accept any spelling of
206 // __has_attribute(const), so assume it is supported.
207 #if defined(__clang__) || defined(__GNUC__)
208 // aka 'CONST' but following LLVM Conventions.
209 #define LLVM_READNONE __attribute__((__const__))
210 #else
211 #define LLVM_READNONE
212 #endif
213 
214 #if __has_attribute(pure) || defined(__GNUC__)
215 // aka 'PURE' but following LLVM Conventions.
216 #define LLVM_READONLY __attribute__((__pure__))
217 #else
218 #define LLVM_READONLY
219 #endif
220 
221 #if __has_attribute(minsize)
222 #define LLVM_ATTRIBUTE_MINSIZE __attribute__((minsize))
223 #else
224 #define LLVM_ATTRIBUTE_MINSIZE
225 #endif
226 
227 #if __has_builtin(__builtin_expect) || defined(__GNUC__)
228 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
229 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
230 #else
231 #define LLVM_LIKELY(EXPR) (EXPR)
232 #define LLVM_UNLIKELY(EXPR) (EXPR)
233 #endif
234 
235 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
236 /// mark a method "not for inlining".
237 #if __has_attribute(noinline)
238 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
239 #elif defined(_MSC_VER)
240 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
241 #else
242 #define LLVM_ATTRIBUTE_NOINLINE
243 #endif
244 
245 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
246 /// so, mark a method "always inline" because it is performance sensitive.
247 #if __has_attribute(always_inline)
248 #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline __attribute__((always_inline))
249 #elif defined(_MSC_VER)
250 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
251 #else
252 #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline
253 #endif
254 
255 /// LLVM_ATTRIBUTE_NO_DEBUG - On compilers where we have a directive to do
256 /// so, mark a method "no debug" because debug info makes the debugger
257 /// experience worse.
258 #if __has_attribute(nodebug)
259 #define LLVM_ATTRIBUTE_NODEBUG __attribute__((nodebug))
260 #else
261 #define LLVM_ATTRIBUTE_NODEBUG
262 #endif
263 
264 #if __has_attribute(returns_nonnull)
265 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
266 #elif defined(_MSC_VER)
267 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
268 #else
269 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
270 #endif
271 
272 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
273 /// pointer that does not alias any other valid pointer.
274 #ifdef __GNUC__
275 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
276 #elif defined(_MSC_VER)
277 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
278 #else
279 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS
280 #endif
281 
282 /// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
283 #if defined(__cplusplus) && __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(fallthrough)
284 #define LLVM_FALLTHROUGH [[fallthrough]]
285 #elif LLVM_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
286 #define LLVM_FALLTHROUGH [[gnu::fallthrough]]
287 #elif __has_attribute(fallthrough)
288 #define LLVM_FALLTHROUGH __attribute__((fallthrough))
289 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::fallthrough)
290 #define LLVM_FALLTHROUGH [[clang::fallthrough]]
291 #else
292 #define LLVM_FALLTHROUGH
293 #endif
294 
295 /// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
296 /// they are constant initialized.
297 #if LLVM_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization)
298 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION                                   \
299   [[clang::require_constant_initialization]]
300 #else
301 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION
302 #endif
303 
304 /// LLVM_GSL_OWNER - Apply this to owning classes like SmallVector to enable
305 /// lifetime warnings.
306 #if LLVM_HAS_CPP_ATTRIBUTE(gsl::Owner)
307 #define LLVM_GSL_OWNER [[gsl::Owner]]
308 #else
309 #define LLVM_GSL_OWNER
310 #endif
311 
312 /// LLVM_GSL_POINTER - Apply this to non-owning classes like
313 /// StringRef to enable lifetime warnings.
314 #if LLVM_HAS_CPP_ATTRIBUTE(gsl::Pointer)
315 #define LLVM_GSL_POINTER [[gsl::Pointer]]
316 #else
317 #define LLVM_GSL_POINTER
318 #endif
319 
320 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
321 /// pedantic diagnostics.
322 #ifdef __GNUC__
323 #define LLVM_EXTENSION __extension__
324 #else
325 #define LLVM_EXTENSION
326 #endif
327 
328 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message")
329 // This macro will be removed.
330 // Use C++14's attribute instead: [[deprecated("message")]]
331 #define LLVM_ATTRIBUTE_DEPRECATED(decl, message) [[deprecated(message)]] decl
332 
333 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
334 /// to an expression which states that it is undefined behavior for the
335 /// compiler to reach this point.  Otherwise is not defined.
336 #if __has_builtin(__builtin_unreachable) || defined(__GNUC__)
337 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
338 #elif defined(_MSC_VER)
339 # define LLVM_BUILTIN_UNREACHABLE __assume(false)
340 #else
341 # define LLVM_BUILTIN_UNREACHABLE
342 #endif
343 
344 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
345 /// which causes the program to exit abnormally.
346 #if __has_builtin(__builtin_trap) || defined(__GNUC__)
347 # define LLVM_BUILTIN_TRAP __builtin_trap()
348 #elif defined(_MSC_VER)
349 // The __debugbreak intrinsic is supported by MSVC, does not require forward
350 // declarations involving platform-specific typedefs (unlike RaiseException),
351 // results in a call to vectored exception handlers, and encodes to a short
352 // instruction that still causes the trapping behavior we want.
353 # define LLVM_BUILTIN_TRAP __debugbreak()
354 #else
355 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
356 #endif
357 
358 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
359 /// an expression which causes the program to break while running
360 /// under a debugger.
361 #if __has_builtin(__builtin_debugtrap)
362 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
363 #elif defined(_MSC_VER)
364 // The __debugbreak intrinsic is supported by MSVC and breaks while
365 // running under the debugger, and also supports invoking a debugger
366 // when the OS is configured appropriately.
367 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
368 #else
369 // Just continue execution when built with compilers that have no
370 // support. This is a debugging aid and not intended to force the
371 // program to abort if encountered.
372 # define LLVM_BUILTIN_DEBUGTRAP
373 #endif
374 
375 /// \macro LLVM_ASSUME_ALIGNED
376 /// Returns a pointer with an assumed alignment.
377 #if __has_builtin(__builtin_assume_aligned) || defined(__GNUC__)
378 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
379 #elif defined(LLVM_BUILTIN_UNREACHABLE)
380 # define LLVM_ASSUME_ALIGNED(p, a) \
381            (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
382 #else
383 # define LLVM_ASSUME_ALIGNED(p, a) (p)
384 #endif
385 
386 /// \macro LLVM_PACKED
387 /// Used to specify a packed structure.
388 /// LLVM_PACKED(
389 ///    struct A {
390 ///      int i;
391 ///      int j;
392 ///      int k;
393 ///      long long l;
394 ///   });
395 ///
396 /// LLVM_PACKED_START
397 /// struct B {
398 ///   int i;
399 ///   int j;
400 ///   int k;
401 ///   long long l;
402 /// };
403 /// LLVM_PACKED_END
404 #ifdef _MSC_VER
405 # define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
406 # define LLVM_PACKED_START __pragma(pack(push, 1))
407 # define LLVM_PACKED_END   __pragma(pack(pop))
408 #else
409 # define LLVM_PACKED(d) d __attribute__((packed))
410 # define LLVM_PACKED_START _Pragma("pack(push, 1)")
411 # define LLVM_PACKED_END   _Pragma("pack(pop)")
412 #endif
413 
414 /// \macro LLVM_PTR_SIZE
415 /// A constant integer equivalent to the value of sizeof(void*).
416 /// Generally used in combination with alignas or when doing computation in the
417 /// preprocessor.
418 #ifdef __SIZEOF_POINTER__
419 # define LLVM_PTR_SIZE __SIZEOF_POINTER__
420 #elif defined(_WIN64)
421 # define LLVM_PTR_SIZE 8
422 #elif defined(_WIN32)
423 # define LLVM_PTR_SIZE 4
424 #elif defined(_MSC_VER)
425 # error "could not determine LLVM_PTR_SIZE as a constant int for MSVC"
426 #else
427 # define LLVM_PTR_SIZE sizeof(void *)
428 #endif
429 
430 /// \macro LLVM_MEMORY_SANITIZER_BUILD
431 /// Whether LLVM itself is built with MemorySanitizer instrumentation.
432 #if __has_feature(memory_sanitizer)
433 # define LLVM_MEMORY_SANITIZER_BUILD 1
434 # include <sanitizer/msan_interface.h>
435 # define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE __attribute__((no_sanitize_memory))
436 #else
437 # define LLVM_MEMORY_SANITIZER_BUILD 0
438 # define __msan_allocated_memory(p, size)
439 # define __msan_unpoison(p, size)
440 # define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE
441 #endif
442 
443 /// \macro LLVM_ADDRESS_SANITIZER_BUILD
444 /// Whether LLVM itself is built with AddressSanitizer instrumentation.
445 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
446 # define LLVM_ADDRESS_SANITIZER_BUILD 1
447 # include <sanitizer/asan_interface.h>
448 #else
449 # define LLVM_ADDRESS_SANITIZER_BUILD 0
450 # define __asan_poison_memory_region(p, size)
451 # define __asan_unpoison_memory_region(p, size)
452 #endif
453 
454 /// \macro LLVM_THREAD_SANITIZER_BUILD
455 /// Whether LLVM itself is built with ThreadSanitizer instrumentation.
456 #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
457 # define LLVM_THREAD_SANITIZER_BUILD 1
458 #else
459 # define LLVM_THREAD_SANITIZER_BUILD 0
460 #endif
461 
462 #if LLVM_THREAD_SANITIZER_BUILD
463 // Thread Sanitizer is a tool that finds races in code.
464 // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
465 // tsan detects these exact functions by name.
466 #ifdef __cplusplus
467 extern "C" {
468 #endif
469 void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
470 void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
471 void AnnotateIgnoreWritesBegin(const char *file, int line);
472 void AnnotateIgnoreWritesEnd(const char *file, int line);
473 #ifdef __cplusplus
474 }
475 #endif
476 
477 // This marker is used to define a happens-before arc. The race detector will
478 // infer an arc from the begin to the end when they share the same pointer
479 // argument.
480 # define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)
481 
482 // This marker defines the destination of a happens-before arc.
483 # define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)
484 
485 // Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
486 # define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
487 
488 // Resume checking for racy writes.
489 # define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
490 #else
491 # define TsanHappensBefore(cv)
492 # define TsanHappensAfter(cv)
493 # define TsanIgnoreWritesBegin()
494 # define TsanIgnoreWritesEnd()
495 #endif
496 
497 /// \macro LLVM_NO_SANITIZE
498 /// Disable a particular sanitizer for a function.
499 #if __has_attribute(no_sanitize)
500 #define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
501 #else
502 #define LLVM_NO_SANITIZE(KIND)
503 #endif
504 
505 /// Mark debug helper function definitions like dump() that should not be
506 /// stripped from debug builds.
507 /// Note that you should also surround dump() functions with
508 /// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always
509 /// get stripped in release builds.
510 // FIXME: Move this to a private config.h as it's not usable in public headers.
511 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
512 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
513 #else
514 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE
515 #endif
516 
517 /// \macro LLVM_PRETTY_FUNCTION
518 /// Gets a user-friendly looking function signature for the current scope
519 /// using the best available method on each platform.  The exact format of the
520 /// resulting string is implementation specific and non-portable, so this should
521 /// only be used, for example, for logging or diagnostics.
522 #if defined(_MSC_VER)
523 #define LLVM_PRETTY_FUNCTION __FUNCSIG__
524 #elif defined(__GNUC__) || defined(__clang__)
525 #define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__
526 #else
527 #define LLVM_PRETTY_FUNCTION __func__
528 #endif
529 
530 /// \macro LLVM_THREAD_LOCAL
531 /// A thread-local storage specifier which can be used with globals,
532 /// extern globals, and static globals.
533 ///
534 /// This is essentially an extremely restricted analog to C++11's thread_local
535 /// support. It uses thread_local if available, falling back on gcc __thread
536 /// if not. __thread doesn't support many of the C++11 thread_local's
537 /// features. You should only use this for PODs that you can statically
538 /// initialize to some constant value. In almost all circumstances this is most
539 /// appropriate for use with a pointer, integer, or small aggregation of
540 /// pointers and integers.
541 #if LLVM_ENABLE_THREADS
542 #if __has_feature(cxx_thread_local) || defined(_MSC_VER)
543 #define LLVM_THREAD_LOCAL thread_local
544 #else
545 // Clang, GCC, and other compatible compilers used __thread prior to C++11 and
546 // we only need the restricted functionality that provides.
547 #define LLVM_THREAD_LOCAL __thread
548 #endif
549 #else // !LLVM_ENABLE_THREADS
550 // If threading is disabled entirely, this compiles to nothing and you get
551 // a normal global variable.
552 #define LLVM_THREAD_LOCAL
553 #endif
554 
555 /// \macro LLVM_ENABLE_EXCEPTIONS
556 /// Whether LLVM is built with exception support.
557 #if __has_feature(cxx_exceptions)
558 #define LLVM_ENABLE_EXCEPTIONS 1
559 #elif defined(__GNUC__) && defined(__EXCEPTIONS)
560 #define LLVM_ENABLE_EXCEPTIONS 1
561 #elif defined(_MSC_VER) && defined(_CPPUNWIND)
562 #define LLVM_ENABLE_EXCEPTIONS 1
563 #endif
564 
565 /// \macro LLVM_NO_PROFILE_INSTRUMENT_FUNCTION
566 /// Disable the profile instrument for a function.
567 #if __has_attribute(no_profile_instrument_function)
568 #define LLVM_NO_PROFILE_INSTRUMENT_FUNCTION                                    \
569   __attribute__((no_profile_instrument_function))
570 #else
571 #define LLVM_NO_PROFILE_INSTRUMENT_FUNCTION
572 #endif
573 
574 #endif
575