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#ifndef __has_include
43# define __has_include(x) 0
44#endif
45
46// Only use __has_cpp_attribute in C++ mode. GCC defines __has_cpp_attribute in
47// C mode, but the :: in __has_cpp_attribute(scoped::attribute) is invalid.
48#ifndef LLVM_HAS_CPP_ATTRIBUTE
49#if defined(__cplusplus) && defined(__has_cpp_attribute)
50# define LLVM_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
51#else
52# define LLVM_HAS_CPP_ATTRIBUTE(x) 0
53#endif
54#endif
55
56/// \macro LLVM_GNUC_PREREQ
57/// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
58/// available.
59#ifndef LLVM_GNUC_PREREQ
60# if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
61# define LLVM_GNUC_PREREQ(maj, min, patch) \
62 ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
63 ((maj) << 20) + ((min) << 10) + (patch))
64# elif defined(__GNUC__) && defined(__GNUC_MINOR__)
65# define LLVM_GNUC_PREREQ(maj, min, patch) \
66 ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
67# else
68# define LLVM_GNUC_PREREQ(maj, min, patch) 0
69# endif
70#endif
71
72/// \macro LLVM_MSC_PREREQ
73/// Is the compiler MSVC of at least the specified version?
74/// The common \param version values to check for are:
75/// * 1910: VS2017, version 15.1 & 15.2
76/// * 1911: VS2017, version 15.3 & 15.4
77/// * 1912: VS2017, version 15.5
78/// * 1913: VS2017, version 15.6
79/// * 1914: VS2017, version 15.7
80/// * 1915: VS2017, version 15.8
81/// * 1916: VS2017, version 15.9
82/// * 1920: VS2019, version 16.0
83/// * 1921: VS2019, version 16.1
84/// * 1922: VS2019, version 16.2
85/// * 1923: VS2019, version 16.3
86/// * 1924: VS2019, version 16.4
87/// * 1925: VS2019, version 16.5
88/// * 1926: VS2019, version 16.6
89/// * 1927: VS2019, version 16.7
90/// * 1928: VS2019, version 16.8 + 16.9
91/// * 1929: VS2019, version 16.10 + 16.11
92/// * 1930: VS2022, version 17.0
93#ifdef _MSC_VER
94#define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version))
95
96// We require at least VS 2019.
97#if !defined(LLVM_FORCE_USE_OLD_TOOLCHAIN)
98#if !LLVM_MSC_PREREQ(1920)
99#error LLVM requires at least VS 2019.
100#endif
101#endif
102
103#else
104#define LLVM_MSC_PREREQ(version) 0
105#endif
106
107/// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
108/// into a shared library, then the class should be private to the library and
109/// not accessible from outside it. Can also be used to mark variables and
110/// functions, making them private to any shared library they are linked into.
111/// On PE/COFF targets, library visibility is the default, so this isn't needed.
112///
113/// LLVM_EXTERNAL_VISIBILITY - classes, functions, and variables marked with
114/// this attribute will be made public and visible outside of any shared library
115/// they are linked in to.
116
117#if LLVM_HAS_CPP_ATTRIBUTE(gnu::visibility)
118#define LLVM_ATTRIBUTE_VISIBILITY_HIDDEN [[gnu::visibility("hidden")]]
119#define LLVM_ATTRIBUTE_VISIBILITY_DEFAULT [[gnu::visibility("default")]]
120#elif __has_attribute(visibility)
121#define LLVM_ATTRIBUTE_VISIBILITY_HIDDEN __attribute__((visibility("hidden")))
122#define LLVM_ATTRIBUTE_VISIBILITY_DEFAULT __attribute__((visibility("default")))
123#else
124#define LLVM_ATTRIBUTE_VISIBILITY_HIDDEN
125#define LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
126#endif
127
128
129#if (!(defined(_WIN32) || defined(__CYGWIN__)) || \
130 (defined(__MINGW32__) && defined(__clang__)))
131#define LLVM_LIBRARY_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_HIDDEN
132#if defined(LLVM_BUILD_LLVM_DYLIB) || defined(LLVM_BUILD_SHARED_LIBS)
133#define LLVM_EXTERNAL_VISIBILITY LLVM_ATTRIBUTE_VISIBILITY_DEFAULT
134#else
135#define LLVM_EXTERNAL_VISIBILITY
136#endif
137#else
138#define LLVM_LIBRARY_VISIBILITY
139#define LLVM_EXTERNAL_VISIBILITY
140#endif
141
142#if defined(__GNUC__)
143#define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
144#else
145#define LLVM_PREFETCH(addr, rw, locality)
146#endif
147
148#if __has_attribute(used)
149#define LLVM_ATTRIBUTE_USED __attribute__((__used__))
150#else
151#define LLVM_ATTRIBUTE_USED
152#endif
153
154#if defined(__clang__)
155#define LLVM_DEPRECATED(MSG, FIX) __attribute__((deprecated(MSG, FIX)))
156#else
157#define LLVM_DEPRECATED(MSG, FIX) [[deprecated(MSG)]]
158#endif
159
160// clang-format off
161#if defined(__clang__) || defined(__GNUC__)
162#define LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH \
163 _Pragma("GCC diagnostic push") \
164 _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
165#define LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_POP \
166 _Pragma("GCC diagnostic pop")
167#elif defined(_MSC_VER)
168#define LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH \
169 _Pragma("warning(push)") \
170 _Pragma("warning(disable : 4996)")
171#define LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_POP \
172 _Pragma("warning(pop)")
173#else
174#define LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_PUSH
175#define LLVM_SUPPRESS_DEPRECATED_DECLARATIONS_POP
176#endif
177// clang-format on
178
179// Indicate that a non-static, non-const C++ member function reinitializes
180// the entire object to a known state, independent of the previous state of
181// the object.
182//
183// The clang-tidy check bugprone-use-after-move recognizes this attribute as a
184// marker that a moved-from object has left the indeterminate state and can be
185// reused.
186#if LLVM_HAS_CPP_ATTRIBUTE(clang::reinitializes)
187#define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
188#else
189#define LLVM_ATTRIBUTE_REINITIALIZES
190#endif
191
192// Some compilers warn about unused functions. When a function is sometimes
193// used or not depending on build settings (e.g. a function only called from
194// within "assert"), this attribute can be used to suppress such warnings.
195//
196// However, it shouldn't be used for unused *variables*, as those have a much
197// more portable solution:
198// (void)unused_var_name;
199// Prefer cast-to-void wherever it is sufficient.
200#if __has_attribute(unused)
201#define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
202#else
203#define LLVM_ATTRIBUTE_UNUSED
204#endif
205
206// FIXME: Provide this for PE/COFF targets.
207#if __has_attribute(weak) && !defined(__MINGW32__) && !defined(__CYGWIN__) && \
208 !defined(_WIN32)
209#define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
210#else
211#define LLVM_ATTRIBUTE_WEAK
212#endif
213
214// Prior to clang 3.2, clang did not accept any spelling of
215// __has_attribute(const), so assume it is supported.
216#if defined(__clang__) || defined(__GNUC__)
217// aka 'CONST' but following LLVM Conventions.
218#define LLVM_READNONE __attribute__((__const__))
219#else
220#define LLVM_READNONE
221#endif
222
223#if __has_attribute(pure) || defined(__GNUC__)
224// aka 'PURE' but following LLVM Conventions.
225#define LLVM_READONLY __attribute__((__pure__))
226#else
227#define LLVM_READONLY
228#endif
229
230#if __has_attribute(minsize)
231#define LLVM_ATTRIBUTE_MINSIZE __attribute__((minsize))
232#else
233#define LLVM_ATTRIBUTE_MINSIZE
234#endif
235
236#if __has_builtin(__builtin_expect) || defined(__GNUC__)
237#define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
238#define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
239#else
240#define LLVM_LIKELY(EXPR) (EXPR)
241#define LLVM_UNLIKELY(EXPR) (EXPR)
242#endif
243
244/// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
245/// mark a method "not for inlining".
246#if __has_attribute(noinline)
247#define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
248#elif defined(_MSC_VER)
249#define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
250#else
251#define LLVM_ATTRIBUTE_NOINLINE
252#endif
253
254/// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
255/// so, mark a method "always inline" because it is performance sensitive.
256#if __has_attribute(always_inline)
257#define LLVM_ATTRIBUTE_ALWAYS_INLINE inline __attribute__((always_inline))
258#elif defined(_MSC_VER)
259#define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
260#else
261#define LLVM_ATTRIBUTE_ALWAYS_INLINE inline
262#endif
263
264/// LLVM_ATTRIBUTE_NO_DEBUG - On compilers where we have a directive to do
265/// so, mark a method "no debug" because debug info makes the debugger
266/// experience worse.
267#if __has_attribute(nodebug)
268#define LLVM_ATTRIBUTE_NODEBUG __attribute__((nodebug))
269#else
270#define LLVM_ATTRIBUTE_NODEBUG
271#endif
272
273#if __has_attribute(returns_nonnull)
274#define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
275#elif defined(_MSC_VER)
276#define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
277#else
278#define LLVM_ATTRIBUTE_RETURNS_NONNULL
279#endif
280
281/// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
282/// pointer that does not alias any other valid pointer.
283#ifdef __GNUC__
284#define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
285#elif defined(_MSC_VER)
286#define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
287#else
288#define LLVM_ATTRIBUTE_RETURNS_NOALIAS
289#endif
290
291/// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
292#if defined(__cplusplus) && __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(fallthrough)
293#define LLVM_FALLTHROUGH [[fallthrough]]
294#elif LLVM_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
295#define LLVM_FALLTHROUGH [[gnu::fallthrough]]
296#elif __has_attribute(fallthrough)
297#define LLVM_FALLTHROUGH __attribute__((fallthrough))
298#elif LLVM_HAS_CPP_ATTRIBUTE(clang::fallthrough)
299#define LLVM_FALLTHROUGH [[clang::fallthrough]]
300#else
301#define LLVM_FALLTHROUGH
302#endif
303
304/// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
305/// they are constant initialized.
306#if LLVM_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization)
307#define LLVM_REQUIRE_CONSTANT_INITIALIZATION \
308 [[clang::require_constant_initialization]]
309#else
310#define LLVM_REQUIRE_CONSTANT_INITIALIZATION
311#endif
312
313/// LLVM_GSL_OWNER - Apply this to owning classes like SmallVector to enable
314/// lifetime warnings.
315#if LLVM_HAS_CPP_ATTRIBUTE(gsl::Owner)
316#define LLVM_GSL_OWNER [[gsl::Owner]]
317#else
318#define LLVM_GSL_OWNER
319#endif
320
321/// LLVM_GSL_POINTER - Apply this to non-owning classes like
322/// StringRef to enable lifetime warnings.
323#if LLVM_HAS_CPP_ATTRIBUTE(gsl::Pointer)
324#define LLVM_GSL_POINTER [[gsl::Pointer]]
325#else
326#define LLVM_GSL_POINTER
327#endif
328
329#if LLVM_HAS_CPP_ATTRIBUTE(nodiscard) >= 201907L
330#define LLVM_CTOR_NODISCARD [[nodiscard]]
331#else
332#define LLVM_CTOR_NODISCARD
333#endif
334
335/// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
336/// pedantic diagnostics.
337#ifdef __GNUC__
338#define LLVM_EXTENSION __extension__
339#else
340#define LLVM_EXTENSION
341#endif
342
343/// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
344/// to an expression which states that it is undefined behavior for the
345/// compiler to reach this point. Otherwise is not defined.
346///
347/// '#else' is intentionally left out so that other macro logic (e.g.,
348/// LLVM_ASSUME_ALIGNED and llvm_unreachable()) can detect whether
349/// LLVM_BUILTIN_UNREACHABLE has a definition.
350#if __has_builtin(__builtin_unreachable) || defined(__GNUC__)
351# define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
352#elif defined(_MSC_VER)
353# define LLVM_BUILTIN_UNREACHABLE __assume(false)
354#endif
355
356/// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
357/// which causes the program to exit abnormally.
358#if __has_builtin(__builtin_trap) || defined(__GNUC__)
359# define LLVM_BUILTIN_TRAP __builtin_trap()
360#elif defined(_MSC_VER)
361// The __debugbreak intrinsic is supported by MSVC, does not require forward
362// declarations involving platform-specific typedefs (unlike RaiseException),
363// results in a call to vectored exception handlers, and encodes to a short
364// instruction that still causes the trapping behavior we want.
365# define LLVM_BUILTIN_TRAP __debugbreak()
366#else
367# define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
368#endif
369
370/// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
371/// an expression which causes the program to break while running
372/// under a debugger.
373#if __has_builtin(__builtin_debugtrap)
374# define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
375#elif defined(_MSC_VER)
376// The __debugbreak intrinsic is supported by MSVC and breaks while
377// running under the debugger, and also supports invoking a debugger
378// when the OS is configured appropriately.
379# define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
380#else
381// Just continue execution when built with compilers that have no
382// support. This is a debugging aid and not intended to force the
383// program to abort if encountered.
384# define LLVM_BUILTIN_DEBUGTRAP
385#endif
386
387/// \macro LLVM_ASSUME_ALIGNED
388/// Returns a pointer with an assumed alignment.
389#if __has_builtin(__builtin_assume_aligned) || defined(__GNUC__)
390# define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
391#elif defined(LLVM_BUILTIN_UNREACHABLE)
392# define LLVM_ASSUME_ALIGNED(p, a) \
393 (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
394#else
395# define LLVM_ASSUME_ALIGNED(p, a) (p)
396#endif
397
398/// \macro LLVM_PACKED
399/// Used to specify a packed structure.
400/// LLVM_PACKED(
401/// struct A {
402/// int i;
403/// int j;
404/// int k;
405/// long long l;
406/// });
407///
408/// LLVM_PACKED_START
409/// struct B {
410/// int i;
411/// int j;
412/// int k;
413/// long long l;
414/// };
415/// LLVM_PACKED_END
416#ifdef _MSC_VER
417# define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
418# define LLVM_PACKED_START __pragma(pack(push, 1))
419# define LLVM_PACKED_END __pragma(pack(pop))
420#else
421# define LLVM_PACKED(d) d __attribute__((packed))
422# define LLVM_PACKED_START _Pragma("pack(push, 1)")
423# define LLVM_PACKED_END _Pragma("pack(pop)")
424#endif
425
426/// \macro LLVM_MEMORY_SANITIZER_BUILD
427/// Whether LLVM itself is built with MemorySanitizer instrumentation.
428#if __has_feature(memory_sanitizer)
429# define LLVM_MEMORY_SANITIZER_BUILD 1
430# include <sanitizer/msan_interface.h>
431# define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE __attribute__((no_sanitize_memory))
432#else
433# define LLVM_MEMORY_SANITIZER_BUILD 0
434# define __msan_allocated_memory(p, size)
435# define __msan_unpoison(p, size)
436# define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE
437#endif
438
439/// \macro LLVM_ADDRESS_SANITIZER_BUILD
440/// Whether LLVM itself is built with AddressSanitizer instrumentation.
441#if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
442# define LLVM_ADDRESS_SANITIZER_BUILD 1
443#if __has_include(<sanitizer/asan_interface.h>)
444# include <sanitizer/asan_interface.h>
445#else
446// These declarations exist to support ASan with MSVC. If MSVC eventually ships
447// asan_interface.h in their headers, then we can remove this.
448#ifdef __cplusplus
449extern "C" {
450#endif
451void __asan_poison_memory_region(void const volatile *addr, size_t size);
452void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
453#ifdef __cplusplus
454} // extern "C"
455#endif
456#endif
457#else
458# define LLVM_ADDRESS_SANITIZER_BUILD 0
459# define __asan_poison_memory_region(p, size)
460# define __asan_unpoison_memory_region(p, size)
461#endif
462
463/// \macro LLVM_HWADDRESS_SANITIZER_BUILD
464/// Whether LLVM itself is built with HWAddressSanitizer instrumentation.
465#if __has_feature(hwaddress_sanitizer)
466#define LLVM_HWADDRESS_SANITIZER_BUILD 1
467#else
468#define LLVM_HWADDRESS_SANITIZER_BUILD 0
469#endif
470
471/// \macro LLVM_THREAD_SANITIZER_BUILD
472/// Whether LLVM itself is built with ThreadSanitizer instrumentation.
473#if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
474# define LLVM_THREAD_SANITIZER_BUILD 1
475#else
476# define LLVM_THREAD_SANITIZER_BUILD 0
477#endif
478
479#if LLVM_THREAD_SANITIZER_BUILD
480// Thread Sanitizer is a tool that finds races in code.
481// See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
482// tsan detects these exact functions by name.
483#ifdef __cplusplus
484extern "C" {
485#endif
486void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
487void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
488void AnnotateIgnoreWritesBegin(const char *file, int line);
489void AnnotateIgnoreWritesEnd(const char *file, int line);
490#ifdef __cplusplus
491}
492#endif
493
494// This marker is used to define a happens-before arc. The race detector will
495// infer an arc from the begin to the end when they share the same pointer
496// argument.
497# define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)
498
499// This marker defines the destination of a happens-before arc.
500# define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)
501
502// Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
503# define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
504
505// Resume checking for racy writes.
506# define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
507#else
508# define TsanHappensBefore(cv)
509# define TsanHappensAfter(cv)
510# define TsanIgnoreWritesBegin()
511# define TsanIgnoreWritesEnd()
512#endif
513
514/// \macro LLVM_NO_SANITIZE
515/// Disable a particular sanitizer for a function.
516#if __has_attribute(no_sanitize)
517#define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
518#else
519#define LLVM_NO_SANITIZE(KIND)
520#endif
521
522/// Mark debug helper function definitions like dump() that should not be
523/// stripped from debug builds.
524/// Note that you should also surround dump() functions with
525/// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always
526/// get stripped in release builds.
527// FIXME: Move this to a private config.h as it's not usable in public headers.
528#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
529#define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
530#else
531#define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE
532#endif
533
534/// \macro LLVM_PRETTY_FUNCTION
535/// Gets a user-friendly looking function signature for the current scope
536/// using the best available method on each platform. The exact format of the
537/// resulting string is implementation specific and non-portable, so this should
538/// only be used, for example, for logging or diagnostics.
539#if defined(_MSC_VER)
540#define LLVM_PRETTY_FUNCTION __FUNCSIG__
541#elif defined(__GNUC__) || defined(__clang__)
542#define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__
543#else
544#define LLVM_PRETTY_FUNCTION __func__
545#endif
546
547/// \macro LLVM_THREAD_LOCAL
548/// A thread-local storage specifier which can be used with globals,
549/// extern globals, and static globals.
550///
551/// This is essentially an extremely restricted analog to C++11's thread_local
552/// support. It uses thread_local if available, falling back on gcc __thread
553/// if not. __thread doesn't support many of the C++11 thread_local's
554/// features. You should only use this for PODs that you can statically
555/// initialize to some constant value. In almost all circumstances this is most
556/// appropriate for use with a pointer, integer, or small aggregation of
557/// pointers and integers.
558#if LLVM_ENABLE_THREADS
559#if __has_feature(cxx_thread_local) || defined(_MSC_VER)
560#define LLVM_THREAD_LOCAL thread_local
561#else
562// Clang, GCC, and other compatible compilers used __thread prior to C++11 and
563// we only need the restricted functionality that provides.
564#define LLVM_THREAD_LOCAL __thread
565#endif
566#else // !LLVM_ENABLE_THREADS
567// If threading is disabled entirely, this compiles to nothing and you get
568// a normal global variable.
569#define LLVM_THREAD_LOCAL
570#endif
571
572/// \macro LLVM_ENABLE_EXCEPTIONS
573/// Whether LLVM is built with exception support.
574#if __has_feature(cxx_exceptions)
575#define LLVM_ENABLE_EXCEPTIONS 1
576#elif defined(__GNUC__) && defined(__EXCEPTIONS)
577#define LLVM_ENABLE_EXCEPTIONS 1
578#elif defined(_MSC_VER) && defined(_CPPUNWIND)
579#define LLVM_ENABLE_EXCEPTIONS 1
580#endif
581
582/// \macro LLVM_NO_PROFILE_INSTRUMENT_FUNCTION
583/// Disable the profile instrument for a function.
584#if __has_attribute(no_profile_instrument_function)
585#define LLVM_NO_PROFILE_INSTRUMENT_FUNCTION \
586 __attribute__((no_profile_instrument_function))
587#else
588#define LLVM_NO_PROFILE_INSTRUMENT_FUNCTION
589#endif
590
591/// \macro LLVM_PREFERRED_TYPE
592/// Adjust type of bit-field in debug info.
593#if __has_attribute(preferred_type)
594#define LLVM_PREFERRED_TYPE(T) __attribute__((preferred_type(T)))
595#else
596#define LLVM_PREFERRED_TYPE(T)
597#endif
598
599#endif
600

source code of llvm/include/llvm/Support/Compiler.h