LLVM  10.0.0svn
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.
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 
141 // Use the 'nodiscard' attribute in C++17 or newer mode.
142 #if __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
143 #define LLVM_NODISCARD [[nodiscard]]
144 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::warn_unused_result)
145 #define LLVM_NODISCARD [[clang::warn_unused_result]]
146 // Clang in C++14 mode claims that it has the 'nodiscard' attribute, but also
147 // warns in the pedantic mode that 'nodiscard' is a C++17 extension (PR33518).
148 // Use the 'nodiscard' attribute in C++14 mode only with GCC.
149 // TODO: remove this workaround when PR33518 is resolved.
150 #elif defined(__GNUC__) && LLVM_HAS_CPP_ATTRIBUTE(nodiscard)
151 #define LLVM_NODISCARD [[nodiscard]]
152 #else
153 #define LLVM_NODISCARD
154 #endif
155 
156 // Indicate that a non-static, non-const C++ member function reinitializes
157 // the entire object to a known state, independent of the previous state of
158 // the object.
159 //
160 // The clang-tidy check bugprone-use-after-move recognizes this attribute as a
161 // marker that a moved-from object has left the indeterminate state and can be
162 // reused.
163 #if LLVM_HAS_CPP_ATTRIBUTE(clang::reinitializes)
164 #define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
165 #else
166 #define LLVM_ATTRIBUTE_REINITIALIZES
167 #endif
168 
169 // Some compilers warn about unused functions. When a function is sometimes
170 // used or not depending on build settings (e.g. a function only called from
171 // within "assert"), this attribute can be used to suppress such warnings.
172 //
173 // However, it shouldn't be used for unused *variables*, as those have a much
174 // more portable solution:
175 // (void)unused_var_name;
176 // Prefer cast-to-void wherever it is sufficient.
177 #if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0)
178 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
179 #else
180 #define LLVM_ATTRIBUTE_UNUSED
181 #endif
182 
183 // FIXME: Provide this for PE/COFF targets.
184 #if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
185  (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32))
186 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
187 #else
188 #define LLVM_ATTRIBUTE_WEAK
189 #endif
190 
191 // Prior to clang 3.2, clang did not accept any spelling of
192 // __has_attribute(const), so assume it is supported.
193 #if defined(__clang__) || defined(__GNUC__)
194 // aka 'CONST' but following LLVM Conventions.
195 #define LLVM_READNONE __attribute__((__const__))
196 #else
197 #define LLVM_READNONE
198 #endif
199 
200 #if __has_attribute(pure) || defined(__GNUC__)
201 // aka 'PURE' but following LLVM Conventions.
202 #define LLVM_READONLY __attribute__((__pure__))
203 #else
204 #define LLVM_READONLY
205 #endif
206 
207 #if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0)
208 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
209 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
210 #else
211 #define LLVM_LIKELY(EXPR) (EXPR)
212 #define LLVM_UNLIKELY(EXPR) (EXPR)
213 #endif
214 
215 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
216 /// mark a method "not for inlining".
217 #if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0)
218 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
219 #elif defined(_MSC_VER)
220 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
221 #else
222 #define LLVM_ATTRIBUTE_NOINLINE
223 #endif
224 
225 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
226 /// so, mark a method "always inline" because it is performance sensitive. GCC
227 /// 3.4 supported this but is buggy in various cases and produces unimplemented
228 /// errors, just use it in GCC 4.0 and later.
229 #if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0)
230 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
231 #elif defined(_MSC_VER)
232 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
233 #else
234 #define LLVM_ATTRIBUTE_ALWAYS_INLINE
235 #endif
236 
237 #ifdef __GNUC__
238 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn))
239 #elif defined(_MSC_VER)
240 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn)
241 #else
242 #define LLVM_ATTRIBUTE_NORETURN
243 #endif
244 
245 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0)
246 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
247 #elif defined(_MSC_VER)
248 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
249 #else
250 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
251 #endif
252 
253 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
254 /// pointer that does not alias any other valid pointer.
255 #ifdef __GNUC__
256 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
257 #elif defined(_MSC_VER)
258 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
259 #else
260 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS
261 #endif
262 
263 /// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
264 #if __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(fallthrough)
265 #define LLVM_FALLTHROUGH [[fallthrough]]
266 #elif LLVM_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
267 #define LLVM_FALLTHROUGH [[gnu::fallthrough]]
268 #elif __has_attribute(fallthrough)
269 #define LLVM_FALLTHROUGH __attribute__((fallthrough))
270 #elif LLVM_HAS_CPP_ATTRIBUTE(clang::fallthrough)
271 #define LLVM_FALLTHROUGH [[clang::fallthrough]]
272 #else
273 #define LLVM_FALLTHROUGH
274 #endif
275 
276 /// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
277 /// they are constant initialized.
278 #if LLVM_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization)
279 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION \
280  [[clang::require_constant_initialization]]
281 #else
282 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION
283 #endif
284 
285 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
286 /// pedantic diagnostics.
287 #ifdef __GNUC__
288 #define LLVM_EXTENSION __extension__
289 #else
290 #define LLVM_EXTENSION
291 #endif
292 
293 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message")
294 #if __has_feature(attribute_deprecated_with_message)
295 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
296  decl __attribute__((deprecated(message)))
297 #elif defined(__GNUC__)
298 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
299  decl __attribute__((deprecated))
300 #elif defined(_MSC_VER)
301 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
302  __declspec(deprecated(message)) decl
303 #else
304 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
305  decl
306 #endif
307 
308 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
309 /// to an expression which states that it is undefined behavior for the
310 /// compiler to reach this point. Otherwise is not defined.
311 #if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0)
312 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
313 #elif defined(_MSC_VER)
314 # define LLVM_BUILTIN_UNREACHABLE __assume(false)
315 #endif
316 
317 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
318 /// which causes the program to exit abnormally.
319 #if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0)
320 # define LLVM_BUILTIN_TRAP __builtin_trap()
321 #elif defined(_MSC_VER)
322 // The __debugbreak intrinsic is supported by MSVC, does not require forward
323 // declarations involving platform-specific typedefs (unlike RaiseException),
324 // results in a call to vectored exception handlers, and encodes to a short
325 // instruction that still causes the trapping behavior we want.
326 # define LLVM_BUILTIN_TRAP __debugbreak()
327 #else
328 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
329 #endif
330 
331 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
332 /// an expression which causes the program to break while running
333 /// under a debugger.
334 #if __has_builtin(__builtin_debugtrap)
335 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
336 #elif defined(_MSC_VER)
337 // The __debugbreak intrinsic is supported by MSVC and breaks while
338 // running under the debugger, and also supports invoking a debugger
339 // when the OS is configured appropriately.
340 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
341 #else
342 // Just continue execution when built with compilers that have no
343 // support. This is a debugging aid and not intended to force the
344 // program to abort if encountered.
345 # define LLVM_BUILTIN_DEBUGTRAP
346 #endif
347 
348 /// \macro LLVM_ASSUME_ALIGNED
349 /// Returns a pointer with an assumed alignment.
350 #if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0)
351 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
352 #elif defined(LLVM_BUILTIN_UNREACHABLE)
353 // As of today, clang does not support __builtin_assume_aligned.
354 # define LLVM_ASSUME_ALIGNED(p, a) \
355  (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
356 #else
357 # define LLVM_ASSUME_ALIGNED(p, a) (p)
358 #endif
359 
360 /// \macro LLVM_PACKED
361 /// Used to specify a packed structure.
362 /// LLVM_PACKED(
363 /// struct A {
364 /// int i;
365 /// int j;
366 /// int k;
367 /// long long l;
368 /// });
369 ///
370 /// LLVM_PACKED_START
371 /// struct B {
372 /// int i;
373 /// int j;
374 /// int k;
375 /// long long l;
376 /// };
377 /// LLVM_PACKED_END
378 #ifdef _MSC_VER
379 # define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
380 # define LLVM_PACKED_START __pragma(pack(push, 1))
381 # define LLVM_PACKED_END __pragma(pack(pop))
382 #else
383 # define LLVM_PACKED(d) d __attribute__((packed))
384 # define LLVM_PACKED_START _Pragma("pack(push, 1)")
385 # define LLVM_PACKED_END _Pragma("pack(pop)")
386 #endif
387 
388 /// \macro LLVM_PTR_SIZE
389 /// A constant integer equivalent to the value of sizeof(void*).
390 /// Generally used in combination with alignas or when doing computation in the
391 /// preprocessor.
392 #ifdef __SIZEOF_POINTER__
393 # define LLVM_PTR_SIZE __SIZEOF_POINTER__
394 #elif defined(_WIN64)
395 # define LLVM_PTR_SIZE 8
396 #elif defined(_WIN32)
397 # define LLVM_PTR_SIZE 4
398 #elif defined(_MSC_VER)
399 # error "could not determine LLVM_PTR_SIZE as a constant int for MSVC"
400 #else
401 # define LLVM_PTR_SIZE sizeof(void *)
402 #endif
403 
404 /// \macro LLVM_MEMORY_SANITIZER_BUILD
405 /// Whether LLVM itself is built with MemorySanitizer instrumentation.
406 #if __has_feature(memory_sanitizer)
407 # define LLVM_MEMORY_SANITIZER_BUILD 1
408 # include <sanitizer/msan_interface.h>
409 #else
410 # define LLVM_MEMORY_SANITIZER_BUILD 0
411 # define __msan_allocated_memory(p, size)
412 # define __msan_unpoison(p, size)
413 #endif
414 
415 /// \macro LLVM_ADDRESS_SANITIZER_BUILD
416 /// Whether LLVM itself is built with AddressSanitizer instrumentation.
417 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
418 # define LLVM_ADDRESS_SANITIZER_BUILD 1
419 # include <sanitizer/asan_interface.h>
420 #else
421 # define LLVM_ADDRESS_SANITIZER_BUILD 0
422 # define __asan_poison_memory_region(p, size)
423 # define __asan_unpoison_memory_region(p, size)
424 #endif
425 
426 /// \macro LLVM_THREAD_SANITIZER_BUILD
427 /// Whether LLVM itself is built with ThreadSanitizer instrumentation.
428 #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
429 # define LLVM_THREAD_SANITIZER_BUILD 1
430 #else
431 # define LLVM_THREAD_SANITIZER_BUILD 0
432 #endif
433 
434 #if LLVM_THREAD_SANITIZER_BUILD
435 // Thread Sanitizer is a tool that finds races in code.
436 // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
437 // tsan detects these exact functions by name.
438 #ifdef __cplusplus
439 extern "C" {
440 #endif
441 void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
442 void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
443 void AnnotateIgnoreWritesBegin(const char *file, int line);
444 void AnnotateIgnoreWritesEnd(const char *file, int line);
445 #ifdef __cplusplus
446 }
447 #endif
448 
449 // This marker is used to define a happens-before arc. The race detector will
450 // infer an arc from the begin to the end when they share the same pointer
451 // argument.
452 # define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)
453 
454 // This marker defines the destination of a happens-before arc.
455 # define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)
456 
457 // Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
458 # define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
459 
460 // Resume checking for racy writes.
461 # define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
462 #else
463 # define TsanHappensBefore(cv)
464 # define TsanHappensAfter(cv)
465 # define TsanIgnoreWritesBegin()
466 # define TsanIgnoreWritesEnd()
467 #endif
468 
469 /// \macro LLVM_NO_SANITIZE
470 /// Disable a particular sanitizer for a function.
471 #if __has_attribute(no_sanitize)
472 #define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
473 #else
474 #define LLVM_NO_SANITIZE(KIND)
475 #endif
476 
477 /// Mark debug helper function definitions like dump() that should not be
478 /// stripped from debug builds.
479 /// Note that you should also surround dump() functions with
480 /// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always
481 /// get stripped in release builds.
482 // FIXME: Move this to a private config.h as it's not usable in public headers.
483 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
484 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
485 #else
486 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE
487 #endif
488 
489 /// \macro LLVM_PRETTY_FUNCTION
490 /// Gets a user-friendly looking function signature for the current scope
491 /// using the best available method on each platform. The exact format of the
492 /// resulting string is implementation specific and non-portable, so this should
493 /// only be used, for example, for logging or diagnostics.
494 #if defined(_MSC_VER)
495 #define LLVM_PRETTY_FUNCTION __FUNCSIG__
496 #elif defined(__GNUC__) || defined(__clang__)
497 #define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__
498 #else
499 #define LLVM_PRETTY_FUNCTION __func__
500 #endif
501 
502 /// \macro LLVM_THREAD_LOCAL
503 /// A thread-local storage specifier which can be used with globals,
504 /// extern globals, and static globals.
505 ///
506 /// This is essentially an extremely restricted analog to C++11's thread_local
507 /// support, and uses that when available. However, it falls back on
508 /// platform-specific or vendor-provided extensions when necessary. These
509 /// extensions don't support many of the C++11 thread_local's features. You
510 /// should only use this for PODs that you can statically initialize to
511 /// some constant value. In almost all circumstances this is most appropriate
512 /// for use with a pointer, integer, or small aggregation of pointers and
513 /// integers.
514 #if LLVM_ENABLE_THREADS
515 #if __has_feature(cxx_thread_local)
516 #define LLVM_THREAD_LOCAL thread_local
517 #elif defined(_MSC_VER)
518 // MSVC supports this with a __declspec.
519 #define LLVM_THREAD_LOCAL __declspec(thread)
520 #else
521 // Clang, GCC, and other compatible compilers used __thread prior to C++11 and
522 // we only need the restricted functionality that provides.
523 #define LLVM_THREAD_LOCAL __thread
524 #endif
525 #else // !LLVM_ENABLE_THREADS
526 // If threading is disabled entirely, this compiles to nothing and you get
527 // a normal global variable.
528 #define LLVM_THREAD_LOCAL
529 #endif
530 
531 /// \macro LLVM_ENABLE_EXCEPTIONS
532 /// Whether LLVM is built with exception support.
533 #if __has_feature(cxx_exceptions)
534 #define LLVM_ENABLE_EXCEPTIONS 1
535 #elif defined(__GNUC__) && defined(__EXCEPTIONS)
536 #define LLVM_ENABLE_EXCEPTIONS 1
537 #elif defined(_MSC_VER) && defined(_CPPUNWIND)
538 #define LLVM_ENABLE_EXCEPTIONS 1
539 #endif
540 
541 #ifdef __cplusplus
542 namespace llvm {
543 
544 /// Allocate a buffer of memory with the given size and alignment.
545 ///
546 /// When the compiler supports aligned operator new, this will use it to to
547 /// handle even over-aligned allocations.
548 ///
549 /// However, this doesn't make any attempt to leverage the fancier techniques
550 /// like posix_memalign due to portability. It is mostly intended to allow
551 /// compatibility with platforms that, after aligned allocation was added, use
552 /// reduced default alignment.
553 inline void *allocate_buffer(size_t Size, size_t Alignment) {
554  return ::operator new(Size
555 #ifdef __cpp_aligned_new
556  ,
557  std::align_val_t(Alignment)
558 #endif
559  );
560 }
561 
562 /// Deallocate a buffer of memory with the given size and alignment.
563 ///
564 /// If supported, this will used the sized delete operator. Also if supported,
565 /// this will pass the alignment to the delete operator.
566 ///
567 /// The pointer must have been allocated with the corresponding new operator,
568 /// most likely using the above helper.
569 inline void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment) {
570  ::operator delete(Ptr
571 #ifdef __cpp_sized_deallocation
572  ,
573  Size
574 #endif
575 #ifdef __cpp_aligned_new
576  ,
577  std::align_val_t(Alignment)
578 #endif
579  );
580 }
581 
582 } // End namespace llvm
583 
584 #endif // __cplusplus
585 #endif
*ViewGraph Emit a dot run run gv on the postscript file
Definition: GraphWriter.h:362
This class represents lattice values for constants.
Definition: AllocatorList.h:23
uint32_t Size
Definition: Profile.cpp:46