LLVM  13.0.0git
Compiler.h
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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. This appears to be
99 /// corrected in MSVC 2019 but not MSVC 2017.
100 #if __has_feature(cxx_rvalue_references) || LLVM_GNUC_PREREQ(4, 8, 1) || \
101  LLVM_MSC_PREREQ(1920)
102 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1
103 #else
104 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0
105 #endif
106 
107 /// Expands to '&' if ref-qualifiers for *this are supported.
108 ///
109 /// This can be used to provide lvalue/rvalue overrides of member functions.
110 /// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
111 #if LLVM_HAS_RVALUE_REFERENCE_THIS
112 #define LLVM_LVALUE_FUNCTION &
113 #else
114 #define LLVM_LVALUE_FUNCTION
115 #endif
116 
117 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
118 /// into a shared library, then the class should be private to the library and
119 /// not accessible from outside it. Can also be used to mark variables and
120 /// functions, making them private to any shared library they are linked into.
121 /// On PE/COFF targets, library visibility is the default, so this isn't needed.
122 ///
123 /// LLVM_EXTERNAL_VISIBILITY - classes, functions, and variables marked with
124 /// this attribute will be made public and visible outside of any shared library
125 /// they are linked in to.
126 #if (__has_attribute(visibility) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
127  !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32)
128 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
129 #define LLVM_EXTERNAL_VISIBILITY __attribute__ ((visibility("default")))
130 #else
131 #define LLVM_LIBRARY_VISIBILITY
132 #define LLVM_EXTERNAL_VISIBILITY
133 #endif
134 
135 #if defined(__GNUC__)
136 #define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
137 #else
138 #define LLVM_PREFETCH(addr, rw, locality)
139 #endif
140 
141 #if __has_attribute(used) || LLVM_GNUC_PREREQ(3, 1, 0)
142 #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
143 #else
144 #define LLVM_ATTRIBUTE_USED
145 #endif
146 
147 /// LLVM_NODISCARD - Warn if a type or return value is discarded.
148 
149 // Use the 'nodiscard' attribute in C++17 or newer mode.
150 #if defined(__cplusplus) && __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
151 #define LLVM_NODISCARD [[nodiscard]]
152 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::warn_unused_result)
153 #define LLVM_NODISCARD [[clang::warn_unused_result]]
154 // Clang in C++14 mode claims that it has the 'nodiscard' attribute, but also
155 // warns in the pedantic mode that 'nodiscard' is a C++17 extension (PR33518).
156 // Use the 'nodiscard' attribute in C++14 mode only with GCC.
157 // TODO: remove this workaround when PR33518 is resolved.
158 #elif defined(__GNUC__) && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
159 #define LLVM_NODISCARD [[nodiscard]]
160 #else
161 #define LLVM_NODISCARD
162 #endif
163 
164 // Indicate that a non-static, non-const C++ member function reinitializes
165 // the entire object to a known state, independent of the previous state of
166 // the object.
167 //
168 // The clang-tidy check bugprone-use-after-move recognizes this attribute as a
169 // marker that a moved-from object has left the indeterminate state and can be
170 // reused.
171 #if LLVM_HAS_CPP_ATTRIBUTE(clang::reinitializes)
172 #define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
173 #else
174 #define LLVM_ATTRIBUTE_REINITIALIZES
175 #endif
176 
177 // Some compilers warn about unused functions. When a function is sometimes
178 // used or not depending on build settings (e.g. a function only called from
179 // within "assert"), this attribute can be used to suppress such warnings.
180 //
181 // However, it shouldn't be used for unused *variables*, as those have a much
182 // more portable solution:
183 // (void)unused_var_name;
184 // Prefer cast-to-void wherever it is sufficient.
185 #if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0)
186 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
187 #else
188 #define LLVM_ATTRIBUTE_UNUSED
189 #endif
190 
191 // FIXME: Provide this for PE/COFF targets.
192 #if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
193  (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32))
194 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
195 #else
196 #define LLVM_ATTRIBUTE_WEAK
197 #endif
198 
199 // Prior to clang 3.2, clang did not accept any spelling of
200 // __has_attribute(const), so assume it is supported.
201 #if defined(__clang__) || defined(__GNUC__)
202 // aka 'CONST' but following LLVM Conventions.
203 #define LLVM_READNONE __attribute__((__const__))
204 #else
205 #define LLVM_READNONE
206 #endif
207 
208 #if __has_attribute(pure) || defined(__GNUC__)
209 // aka 'PURE' but following LLVM Conventions.
210 #define LLVM_READONLY __attribute__((__pure__))
211 #else
212 #define LLVM_READONLY
213 #endif
214 
215 #if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0)
216 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
217 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
218 #else
219 #define LLVM_LIKELY(EXPR) (EXPR)
220 #define LLVM_UNLIKELY(EXPR) (EXPR)
221 #endif
222 
223 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
224 /// mark a method "not for inlining".
225 #if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0)
226 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
227 #elif defined(_MSC_VER)
228 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
229 #else
230 #define LLVM_ATTRIBUTE_NOINLINE
231 #endif
232 
233 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
234 /// so, mark a method "always inline" because it is performance sensitive. GCC
235 /// 3.4 supported this but is buggy in various cases and produces unimplemented
236 /// errors, just use it in GCC 4.0 and later.
237 #if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0)
238 #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline __attribute__((always_inline))
239 #elif defined(_MSC_VER)
240 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
241 #else
242 #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline
243 #endif
244 
245 #ifdef __GNUC__
246 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn))
247 #elif defined(_MSC_VER)
248 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn)
249 #else
250 #define LLVM_ATTRIBUTE_NORETURN
251 #endif
252 
253 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0)
254 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
255 #elif defined(_MSC_VER)
256 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
257 #else
258 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
259 #endif
260 
261 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
262 /// pointer that does not alias any other valid pointer.
263 #ifdef __GNUC__
264 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
265 #elif defined(_MSC_VER)
266 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
267 #else
268 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS
269 #endif
270 
271 /// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
272 #if defined(__cplusplus) && __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(fallthrough)
273 #define LLVM_FALLTHROUGH [[fallthrough]]
274 #elif LLVM_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
275 #define LLVM_FALLTHROUGH [[gnu::fallthrough]]
276 #elif __has_attribute(fallthrough)
277 #define LLVM_FALLTHROUGH __attribute__((fallthrough))
278 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::fallthrough)
279 #define LLVM_FALLTHROUGH [[clang::fallthrough]]
280 #else
281 #define LLVM_FALLTHROUGH
282 #endif
283 
284 /// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
285 /// they are constant initialized.
286 #if LLVM_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization)
287 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION \
288  [[clang::require_constant_initialization]]
289 #else
290 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION
291 #endif
292 
293 /// LLVM_GSL_OWNER - Apply this to owning classes like SmallVector to enable
294 /// lifetime warnings.
295 #if LLVM_HAS_CPP_ATTRIBUTE(gsl::Owner)
296 #define LLVM_GSL_OWNER [[gsl::Owner]]
297 #else
298 #define LLVM_GSL_OWNER
299 #endif
300 
301 /// LLVM_GSL_POINTER - Apply this to non-owning classes like
302 /// StringRef to enable lifetime warnings.
303 #if LLVM_HAS_CPP_ATTRIBUTE(gsl::Pointer)
304 #define LLVM_GSL_POINTER [[gsl::Pointer]]
305 #else
306 #define LLVM_GSL_POINTER
307 #endif
308 
309 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
310 /// pedantic diagnostics.
311 #ifdef __GNUC__
312 #define LLVM_EXTENSION __extension__
313 #else
314 #define LLVM_EXTENSION
315 #endif
316 
317 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message")
318 // This macro will be removed.
319 // Use C++14's attribute instead: [[deprecated("message")]]
320 #define LLVM_ATTRIBUTE_DEPRECATED(decl, message) [[deprecated(message)]] decl
321 
322 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
323 /// to an expression which states that it is undefined behavior for the
324 /// compiler to reach this point. Otherwise is not defined.
325 #if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0)
326 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
327 #elif defined(_MSC_VER)
328 # define LLVM_BUILTIN_UNREACHABLE __assume(false)
329 #endif
330 
331 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
332 /// which causes the program to exit abnormally.
333 #if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0)
334 # define LLVM_BUILTIN_TRAP __builtin_trap()
335 #elif defined(_MSC_VER)
336 // The __debugbreak intrinsic is supported by MSVC, does not require forward
337 // declarations involving platform-specific typedefs (unlike RaiseException),
338 // results in a call to vectored exception handlers, and encodes to a short
339 // instruction that still causes the trapping behavior we want.
340 # define LLVM_BUILTIN_TRAP __debugbreak()
341 #else
342 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
343 #endif
344 
345 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
346 /// an expression which causes the program to break while running
347 /// under a debugger.
348 #if __has_builtin(__builtin_debugtrap)
349 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
350 #elif defined(_MSC_VER)
351 // The __debugbreak intrinsic is supported by MSVC and breaks while
352 // running under the debugger, and also supports invoking a debugger
353 // when the OS is configured appropriately.
354 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
355 #else
356 // Just continue execution when built with compilers that have no
357 // support. This is a debugging aid and not intended to force the
358 // program to abort if encountered.
359 # define LLVM_BUILTIN_DEBUGTRAP
360 #endif
361 
362 /// \macro LLVM_ASSUME_ALIGNED
363 /// Returns a pointer with an assumed alignment.
364 #if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0)
365 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
366 #elif defined(LLVM_BUILTIN_UNREACHABLE)
367 # define LLVM_ASSUME_ALIGNED(p, a) \
368  (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
369 #else
370 # define LLVM_ASSUME_ALIGNED(p, a) (p)
371 #endif
372 
373 /// \macro LLVM_PACKED
374 /// Used to specify a packed structure.
375 /// LLVM_PACKED(
376 /// struct A {
377 /// int i;
378 /// int j;
379 /// int k;
380 /// long long l;
381 /// });
382 ///
383 /// LLVM_PACKED_START
384 /// struct B {
385 /// int i;
386 /// int j;
387 /// int k;
388 /// long long l;
389 /// };
390 /// LLVM_PACKED_END
391 #ifdef _MSC_VER
392 # define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
393 # define LLVM_PACKED_START __pragma(pack(push, 1))
394 # define LLVM_PACKED_END __pragma(pack(pop))
395 #else
396 # define LLVM_PACKED(d) d __attribute__((packed))
397 # define LLVM_PACKED_START _Pragma("pack(push, 1)")
398 # define LLVM_PACKED_END _Pragma("pack(pop)")
399 #endif
400 
401 /// \macro LLVM_PTR_SIZE
402 /// A constant integer equivalent to the value of sizeof(void*).
403 /// Generally used in combination with alignas or when doing computation in the
404 /// preprocessor.
405 #ifdef __SIZEOF_POINTER__
406 # define LLVM_PTR_SIZE __SIZEOF_POINTER__
407 #elif defined(_WIN64)
408 # define LLVM_PTR_SIZE 8
409 #elif defined(_WIN32)
410 # define LLVM_PTR_SIZE 4
411 #elif defined(_MSC_VER)
412 # error "could not determine LLVM_PTR_SIZE as a constant int for MSVC"
413 #else
414 # define LLVM_PTR_SIZE sizeof(void *)
415 #endif
416 
417 /// \macro LLVM_MEMORY_SANITIZER_BUILD
418 /// Whether LLVM itself is built with MemorySanitizer instrumentation.
419 #if __has_feature(memory_sanitizer)
420 # define LLVM_MEMORY_SANITIZER_BUILD 1
421 # include <sanitizer/msan_interface.h>
422 # define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE __attribute__((no_sanitize_memory))
423 #else
424 # define LLVM_MEMORY_SANITIZER_BUILD 0
425 # define __msan_allocated_memory(p, size)
426 # define __msan_unpoison(p, size)
427 # define LLVM_NO_SANITIZE_MEMORY_ATTRIBUTE
428 #endif
429 
430 /// \macro LLVM_ADDRESS_SANITIZER_BUILD
431 /// Whether LLVM itself is built with AddressSanitizer instrumentation.
432 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
433 # define LLVM_ADDRESS_SANITIZER_BUILD 1
434 # include <sanitizer/asan_interface.h>
435 #else
436 # define LLVM_ADDRESS_SANITIZER_BUILD 0
437 # define __asan_poison_memory_region(p, size)
438 # define __asan_unpoison_memory_region(p, size)
439 #endif
440 
441 /// \macro LLVM_THREAD_SANITIZER_BUILD
442 /// Whether LLVM itself is built with ThreadSanitizer instrumentation.
443 #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
444 # define LLVM_THREAD_SANITIZER_BUILD 1
445 #else
446 # define LLVM_THREAD_SANITIZER_BUILD 0
447 #endif
448 
449 #if LLVM_THREAD_SANITIZER_BUILD
450 // Thread Sanitizer is a tool that finds races in code.
451 // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
452 // tsan detects these exact functions by name.
453 #ifdef __cplusplus
454 extern "C" {
455 #endif
456 void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
457 void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
458 void AnnotateIgnoreWritesBegin(const char *file, int line);
459 void AnnotateIgnoreWritesEnd(const char *file, int line);
460 #ifdef __cplusplus
461 }
462 #endif
463 
464 // This marker is used to define a happens-before arc. The race detector will
465 // infer an arc from the begin to the end when they share the same pointer
466 // argument.
467 # define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)
468 
469 // This marker defines the destination of a happens-before arc.
470 # define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)
471 
472 // Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
473 # define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
474 
475 // Resume checking for racy writes.
476 # define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
477 #else
478 # define TsanHappensBefore(cv)
479 # define TsanHappensAfter(cv)
480 # define TsanIgnoreWritesBegin()
481 # define TsanIgnoreWritesEnd()
482 #endif
483 
484 /// \macro LLVM_NO_SANITIZE
485 /// Disable a particular sanitizer for a function.
486 #if __has_attribute(no_sanitize)
487 #define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
488 #else
489 #define LLVM_NO_SANITIZE(KIND)
490 #endif
491 
492 /// Mark debug helper function definitions like dump() that should not be
493 /// stripped from debug builds.
494 /// Note that you should also surround dump() functions with
495 /// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always
496 /// get stripped in release builds.
497 // FIXME: Move this to a private config.h as it's not usable in public headers.
498 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
499 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
500 #else
501 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE
502 #endif
503 
504 /// \macro LLVM_PRETTY_FUNCTION
505 /// Gets a user-friendly looking function signature for the current scope
506 /// using the best available method on each platform. The exact format of the
507 /// resulting string is implementation specific and non-portable, so this should
508 /// only be used, for example, for logging or diagnostics.
509 #if defined(_MSC_VER)
510 #define LLVM_PRETTY_FUNCTION __FUNCSIG__
511 #elif defined(__GNUC__) || defined(__clang__)
512 #define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__
513 #else
514 #define LLVM_PRETTY_FUNCTION __func__
515 #endif
516 
517 /// \macro LLVM_THREAD_LOCAL
518 /// A thread-local storage specifier which can be used with globals,
519 /// extern globals, and static globals.
520 ///
521 /// This is essentially an extremely restricted analog to C++11's thread_local
522 /// support. It uses thread_local if available, falling back on gcc __thread
523 /// if not. __thread doesn't support many of the C++11 thread_local's
524 /// features. You should only use this for PODs that you can statically
525 /// initialize to some constant value. In almost all circumstances this is most
526 /// appropriate for use with a pointer, integer, or small aggregation of
527 /// pointers and integers.
528 #if LLVM_ENABLE_THREADS
529 #if __has_feature(cxx_thread_local) || defined(_MSC_VER)
530 #define LLVM_THREAD_LOCAL thread_local
531 #else
532 // Clang, GCC, and other compatible compilers used __thread prior to C++11 and
533 // we only need the restricted functionality that provides.
534 #define LLVM_THREAD_LOCAL __thread
535 #endif
536 #else // !LLVM_ENABLE_THREADS
537 // If threading is disabled entirely, this compiles to nothing and you get
538 // a normal global variable.
539 #define LLVM_THREAD_LOCAL
540 #endif
541 
542 /// \macro LLVM_ENABLE_EXCEPTIONS
543 /// Whether LLVM is built with exception support.
544 #if __has_feature(cxx_exceptions)
545 #define LLVM_ENABLE_EXCEPTIONS 1
546 #elif defined(__GNUC__) && defined(__EXCEPTIONS)
547 #define LLVM_ENABLE_EXCEPTIONS 1
548 #elif defined(_MSC_VER) && defined(_CPPUNWIND)
549 #define LLVM_ENABLE_EXCEPTIONS 1
550 #endif
551 
552 #endif
file
dot regions Print regions of function to dot file(with no function bodies)"