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.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_SUPPORT_COMPILER_H
15 #define LLVM_SUPPORT_COMPILER_H
16 
17 #include "llvm/Config/llvm-config.h"
18 
19 #include <new>
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_cpp_attribute
39 # define __has_cpp_attribute(x) 0
40 #endif
41 
42 #ifndef __has_builtin
43 # define __has_builtin(x) 0
44 #endif
45 
46 /// \macro LLVM_GNUC_PREREQ
47 /// Extend the default __GNUC_PREREQ even if glibc's features.h isn't
48 /// available.
49 #ifndef LLVM_GNUC_PREREQ
50 # if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
51 # define LLVM_GNUC_PREREQ(maj, min, patch) \
52  ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \
53  ((maj) << 20) + ((min) << 10) + (patch))
54 # elif defined(__GNUC__) && defined(__GNUC_MINOR__)
55 # define LLVM_GNUC_PREREQ(maj, min, patch) \
56  ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10))
57 # else
58 # define LLVM_GNUC_PREREQ(maj, min, patch) 0
59 # endif
60 #endif
61 
62 /// \macro LLVM_MSC_PREREQ
63 /// Is the compiler MSVC of at least the specified version?
64 /// The common \param version values to check for are:
65 /// * 1900: Microsoft Visual Studio 2015 / 14.0
66 #ifdef _MSC_VER
67 #define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version))
68 
69 // We require at least MSVC 2015.
70 #if !LLVM_MSC_PREREQ(1900)
71 #error LLVM requires at least MSVC 2015.
72 #endif
73 
74 #else
75 #define LLVM_MSC_PREREQ(version) 0
76 #endif
77 
78 /// Does the compiler support ref-qualifiers for *this?
79 ///
80 /// Sadly, this is separate from just rvalue reference support because GCC
81 /// and MSVC implemented this later than everything else.
82 #if __has_feature(cxx_rvalue_references) || LLVM_GNUC_PREREQ(4, 8, 1)
83 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1
84 #else
85 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0
86 #endif
87 
88 /// Expands to '&' if ref-qualifiers for *this are supported.
89 ///
90 /// This can be used to provide lvalue/rvalue overrides of member functions.
91 /// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
92 #if LLVM_HAS_RVALUE_REFERENCE_THIS
93 #define LLVM_LVALUE_FUNCTION &
94 #else
95 #define LLVM_LVALUE_FUNCTION
96 #endif
97 
98 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
99 /// into a shared library, then the class should be private to the library and
100 /// not accessible from outside it. Can also be used to mark variables and
101 /// functions, making them private to any shared library they are linked into.
102 /// On PE/COFF targets, library visibility is the default, so this isn't needed.
103 #if (__has_attribute(visibility) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
104  !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32)
105 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
106 #else
107 #define LLVM_LIBRARY_VISIBILITY
108 #endif
109 
110 #if defined(__GNUC__)
111 #define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
112 #else
113 #define LLVM_PREFETCH(addr, rw, locality)
114 #endif
115 
116 #if __has_attribute(used) || LLVM_GNUC_PREREQ(3, 1, 0)
117 #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
118 #else
119 #define LLVM_ATTRIBUTE_USED
120 #endif
121 
122 /// LLVM_NODISCARD - Warn if a type or return value is discarded.
123 #if __cplusplus > 201402L && __has_cpp_attribute(nodiscard)
124 #define LLVM_NODISCARD [[nodiscard]]
125 #elif !__cplusplus
126 // Workaround for llvm.org/PR23435, since clang 3.6 and below emit a spurious
127 // error when __has_cpp_attribute is given a scoped attribute in C mode.
128 #define LLVM_NODISCARD
129 #elif __has_cpp_attribute(clang::warn_unused_result)
130 #define LLVM_NODISCARD [[clang::warn_unused_result]]
131 #else
132 #define LLVM_NODISCARD
133 #endif
134 
135 // Indicate that a non-static, non-const C++ member function reinitializes
136 // the entire object to a known state, independent of the previous state of
137 // the object.
138 //
139 // The clang-tidy check bugprone-use-after-move recognizes this attribute as a
140 // marker that a moved-from object has left the indeterminate state and can be
141 // reused.
142 #if __has_cpp_attribute(clang::reinitializes)
143 #define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
144 #else
145 #define LLVM_ATTRIBUTE_REINITIALIZES
146 #endif
147 
148 // Some compilers warn about unused functions. When a function is sometimes
149 // used or not depending on build settings (e.g. a function only called from
150 // within "assert"), this attribute can be used to suppress such warnings.
151 //
152 // However, it shouldn't be used for unused *variables*, as those have a much
153 // more portable solution:
154 // (void)unused_var_name;
155 // Prefer cast-to-void wherever it is sufficient.
156 #if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0)
157 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
158 #else
159 #define LLVM_ATTRIBUTE_UNUSED
160 #endif
161 
162 // FIXME: Provide this for PE/COFF targets.
163 #if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
164  (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32))
165 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
166 #else
167 #define LLVM_ATTRIBUTE_WEAK
168 #endif
169 
170 // Prior to clang 3.2, clang did not accept any spelling of
171 // __has_attribute(const), so assume it is supported.
172 #if defined(__clang__) || defined(__GNUC__)
173 // aka 'CONST' but following LLVM Conventions.
174 #define LLVM_READNONE __attribute__((__const__))
175 #else
176 #define LLVM_READNONE
177 #endif
178 
179 #if __has_attribute(pure) || defined(__GNUC__)
180 // aka 'PURE' but following LLVM Conventions.
181 #define LLVM_READONLY __attribute__((__pure__))
182 #else
183 #define LLVM_READONLY
184 #endif
185 
186 #if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0)
187 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
188 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
189 #else
190 #define LLVM_LIKELY(EXPR) (EXPR)
191 #define LLVM_UNLIKELY(EXPR) (EXPR)
192 #endif
193 
194 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
195 /// mark a method "not for inlining".
196 #if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0)
197 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
198 #elif defined(_MSC_VER)
199 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
200 #else
201 #define LLVM_ATTRIBUTE_NOINLINE
202 #endif
203 
204 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
205 /// so, mark a method "always inline" because it is performance sensitive. GCC
206 /// 3.4 supported this but is buggy in various cases and produces unimplemented
207 /// errors, just use it in GCC 4.0 and later.
208 #if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0)
209 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
210 #elif defined(_MSC_VER)
211 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
212 #else
213 #define LLVM_ATTRIBUTE_ALWAYS_INLINE
214 #endif
215 
216 #ifdef __GNUC__
217 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn))
218 #elif defined(_MSC_VER)
219 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn)
220 #else
221 #define LLVM_ATTRIBUTE_NORETURN
222 #endif
223 
224 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0)
225 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
226 #elif defined(_MSC_VER)
227 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
228 #else
229 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
230 #endif
231 
232 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
233 /// pointer that does not alias any other valid pointer.
234 #ifdef __GNUC__
235 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
236 #elif defined(_MSC_VER)
237 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
238 #else
239 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS
240 #endif
241 
242 /// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
243 #if __cplusplus > 201402L && __has_cpp_attribute(fallthrough)
244 #define LLVM_FALLTHROUGH [[fallthrough]]
245 #elif __has_cpp_attribute(gnu::fallthrough)
246 #define LLVM_FALLTHROUGH [[gnu::fallthrough]]
247 #elif !__cplusplus
248 // Workaround for llvm.org/PR23435, since clang 3.6 and below emit a spurious
249 // error when __has_cpp_attribute is given a scoped attribute in C mode.
250 #define LLVM_FALLTHROUGH
251 #elif __has_cpp_attribute(clang::fallthrough)
252 #define LLVM_FALLTHROUGH [[clang::fallthrough]]
253 #else
254 #define LLVM_FALLTHROUGH
255 #endif
256 
257 /// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
258 /// they are constant initialized.
259 #if __has_cpp_attribute(clang::require_constant_initialization)
260 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION \
261  [[clang::require_constant_initialization]]
262 #else
263 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION
264 #endif
265 
266 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
267 /// pedantic diagnostics.
268 #ifdef __GNUC__
269 #define LLVM_EXTENSION __extension__
270 #else
271 #define LLVM_EXTENSION
272 #endif
273 
274 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message")
275 #if __has_feature(attribute_deprecated_with_message)
276 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
277  decl __attribute__((deprecated(message)))
278 #elif defined(__GNUC__)
279 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
280  decl __attribute__((deprecated))
281 #elif defined(_MSC_VER)
282 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
283  __declspec(deprecated(message)) decl
284 #else
285 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
286  decl
287 #endif
288 
289 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
290 /// to an expression which states that it is undefined behavior for the
291 /// compiler to reach this point. Otherwise is not defined.
292 #if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0)
293 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
294 #elif defined(_MSC_VER)
295 # define LLVM_BUILTIN_UNREACHABLE __assume(false)
296 #endif
297 
298 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
299 /// which causes the program to exit abnormally.
300 #if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0)
301 # define LLVM_BUILTIN_TRAP __builtin_trap()
302 #elif defined(_MSC_VER)
303 // The __debugbreak intrinsic is supported by MSVC, does not require forward
304 // declarations involving platform-specific typedefs (unlike RaiseException),
305 // results in a call to vectored exception handlers, and encodes to a short
306 // instruction that still causes the trapping behavior we want.
307 # define LLVM_BUILTIN_TRAP __debugbreak()
308 #else
309 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
310 #endif
311 
312 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
313 /// an expression which causes the program to break while running
314 /// under a debugger.
315 #if __has_builtin(__builtin_debugtrap)
316 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
317 #elif defined(_MSC_VER)
318 // The __debugbreak intrinsic is supported by MSVC and breaks while
319 // running under the debugger, and also supports invoking a debugger
320 // when the OS is configured appropriately.
321 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
322 #else
323 // Just continue execution when built with compilers that have no
324 // support. This is a debugging aid and not intended to force the
325 // program to abort if encountered.
326 # define LLVM_BUILTIN_DEBUGTRAP
327 #endif
328 
329 /// \macro LLVM_ASSUME_ALIGNED
330 /// Returns a pointer with an assumed alignment.
331 #if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0)
332 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
333 #elif defined(LLVM_BUILTIN_UNREACHABLE)
334 // As of today, clang does not support __builtin_assume_aligned.
335 # define LLVM_ASSUME_ALIGNED(p, a) \
336  (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
337 #else
338 # define LLVM_ASSUME_ALIGNED(p, a) (p)
339 #endif
340 
341 /// \macro LLVM_ALIGNAS
342 /// Used to specify a minimum alignment for a structure or variable.
343 #if __GNUC__ && !__has_feature(cxx_alignas) && !LLVM_GNUC_PREREQ(4, 8, 1)
344 # define LLVM_ALIGNAS(x) __attribute__((aligned(x)))
345 #else
346 # define LLVM_ALIGNAS(x) alignas(x)
347 #endif
348 
349 /// \macro LLVM_PACKED
350 /// Used to specify a packed structure.
351 /// LLVM_PACKED(
352 /// struct A {
353 /// int i;
354 /// int j;
355 /// int k;
356 /// long long l;
357 /// });
358 ///
359 /// LLVM_PACKED_START
360 /// struct B {
361 /// int i;
362 /// int j;
363 /// int k;
364 /// long long l;
365 /// };
366 /// LLVM_PACKED_END
367 #ifdef _MSC_VER
368 # define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop))
369 # define LLVM_PACKED_START __pragma(pack(push, 1))
370 # define LLVM_PACKED_END __pragma(pack(pop))
371 #else
372 # define LLVM_PACKED(d) d __attribute__((packed))
373 # define LLVM_PACKED_START _Pragma("pack(push, 1)")
374 # define LLVM_PACKED_END _Pragma("pack(pop)")
375 #endif
376 
377 /// \macro LLVM_PTR_SIZE
378 /// A constant integer equivalent to the value of sizeof(void*).
379 /// Generally used in combination with LLVM_ALIGNAS or when doing computation in
380 /// the preprocessor.
381 #ifdef __SIZEOF_POINTER__
382 # define LLVM_PTR_SIZE __SIZEOF_POINTER__
383 #elif defined(_WIN64)
384 # define LLVM_PTR_SIZE 8
385 #elif defined(_WIN32)
386 # define LLVM_PTR_SIZE 4
387 #elif defined(_MSC_VER)
388 # error "could not determine LLVM_PTR_SIZE as a constant int for MSVC"
389 #else
390 # define LLVM_PTR_SIZE sizeof(void *)
391 #endif
392 
393 /// \macro LLVM_MEMORY_SANITIZER_BUILD
394 /// Whether LLVM itself is built with MemorySanitizer instrumentation.
395 #if __has_feature(memory_sanitizer)
396 # define LLVM_MEMORY_SANITIZER_BUILD 1
397 # include <sanitizer/msan_interface.h>
398 #else
399 # define LLVM_MEMORY_SANITIZER_BUILD 0
400 # define __msan_allocated_memory(p, size)
401 # define __msan_unpoison(p, size)
402 #endif
403 
404 /// \macro LLVM_ADDRESS_SANITIZER_BUILD
405 /// Whether LLVM itself is built with AddressSanitizer instrumentation.
406 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
407 # define LLVM_ADDRESS_SANITIZER_BUILD 1
408 # include <sanitizer/asan_interface.h>
409 #else
410 # define LLVM_ADDRESS_SANITIZER_BUILD 0
411 # define __asan_poison_memory_region(p, size)
412 # define __asan_unpoison_memory_region(p, size)
413 #endif
414 
415 /// \macro LLVM_THREAD_SANITIZER_BUILD
416 /// Whether LLVM itself is built with ThreadSanitizer instrumentation.
417 #if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__)
418 # define LLVM_THREAD_SANITIZER_BUILD 1
419 #else
420 # define LLVM_THREAD_SANITIZER_BUILD 0
421 #endif
422 
423 #if LLVM_THREAD_SANITIZER_BUILD
424 // Thread Sanitizer is a tool that finds races in code.
425 // See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations .
426 // tsan detects these exact functions by name.
427 #ifdef __cplusplus
428 extern "C" {
429 #endif
430 void AnnotateHappensAfter(const char *file, int line, const volatile void *cv);
431 void AnnotateHappensBefore(const char *file, int line, const volatile void *cv);
432 void AnnotateIgnoreWritesBegin(const char *file, int line);
433 void AnnotateIgnoreWritesEnd(const char *file, int line);
434 #ifdef __cplusplus
435 }
436 #endif
437 
438 // This marker is used to define a happens-before arc. The race detector will
439 // infer an arc from the begin to the end when they share the same pointer
440 // argument.
441 # define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv)
442 
443 // This marker defines the destination of a happens-before arc.
444 # define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv)
445 
446 // Ignore any races on writes between here and the next TsanIgnoreWritesEnd.
447 # define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__)
448 
449 // Resume checking for racy writes.
450 # define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__)
451 #else
452 # define TsanHappensBefore(cv)
453 # define TsanHappensAfter(cv)
454 # define TsanIgnoreWritesBegin()
455 # define TsanIgnoreWritesEnd()
456 #endif
457 
458 /// \macro LLVM_NO_SANITIZE
459 /// Disable a particular sanitizer for a function.
460 #if __has_attribute(no_sanitize)
461 #define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND)))
462 #else
463 #define LLVM_NO_SANITIZE(KIND)
464 #endif
465 
466 /// Mark debug helper function definitions like dump() that should not be
467 /// stripped from debug builds.
468 /// Note that you should also surround dump() functions with
469 /// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always
470 /// get stripped in release builds.
471 // FIXME: Move this to a private config.h as it's not usable in public headers.
472 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
473 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED
474 #else
475 #define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE
476 #endif
477 
478 /// \macro LLVM_PRETTY_FUNCTION
479 /// Gets a user-friendly looking function signature for the current scope
480 /// using the best available method on each platform. The exact format of the
481 /// resulting string is implementation specific and non-portable, so this should
482 /// only be used, for example, for logging or diagnostics.
483 #if defined(_MSC_VER)
484 #define LLVM_PRETTY_FUNCTION __FUNCSIG__
485 #elif defined(__GNUC__) || defined(__clang__)
486 #define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__
487 #else
488 #define LLVM_PRETTY_FUNCTION __func__
489 #endif
490 
491 /// \macro LLVM_THREAD_LOCAL
492 /// A thread-local storage specifier which can be used with globals,
493 /// extern globals, and static globals.
494 ///
495 /// This is essentially an extremely restricted analog to C++11's thread_local
496 /// support, and uses that when available. However, it falls back on
497 /// platform-specific or vendor-provided extensions when necessary. These
498 /// extensions don't support many of the C++11 thread_local's features. You
499 /// should only use this for PODs that you can statically initialize to
500 /// some constant value. In almost all circumstances this is most appropriate
501 /// for use with a pointer, integer, or small aggregation of pointers and
502 /// integers.
503 #if LLVM_ENABLE_THREADS
504 #if __has_feature(cxx_thread_local)
505 #define LLVM_THREAD_LOCAL thread_local
506 #elif defined(_MSC_VER)
507 // MSVC supports this with a __declspec.
508 #define LLVM_THREAD_LOCAL __declspec(thread)
509 #else
510 // Clang, GCC, and other compatible compilers used __thread prior to C++11 and
511 // we only need the restricted functionality that provides.
512 #define LLVM_THREAD_LOCAL __thread
513 #endif
514 #else // !LLVM_ENABLE_THREADS
515 // If threading is disabled entirely, this compiles to nothing and you get
516 // a normal global variable.
517 #define LLVM_THREAD_LOCAL
518 #endif
519 
520 /// \macro LLVM_ENABLE_EXCEPTIONS
521 /// Whether LLVM is built with exception support.
522 #if __has_feature(cxx_exceptions)
523 #define LLVM_ENABLE_EXCEPTIONS 1
524 #elif defined(__GNUC__) && defined(__EXCEPTIONS)
525 #define LLVM_ENABLE_EXCEPTIONS 1
526 #elif defined(_MSC_VER) && defined(_CPPUNWIND)
527 #define LLVM_ENABLE_EXCEPTIONS 1
528 #endif
529 
530 namespace llvm {
531 
532 /// Allocate a buffer of memory with the given size and alignment.
533 ///
534 /// When the compiler supports aligned operator new, this will use it to to
535 /// handle even over-aligned allocations.
536 ///
537 /// However, this doesn't make any attempt to leverage the fancier techniques
538 /// like posix_memalign due to portability. It is mostly intended to allow
539 /// compatibility with platforms that, after aligned allocation was added, use
540 /// reduced default alignment.
541 inline void *allocate_buffer(size_t Size, size_t Alignment) {
542  return ::operator new(Size
543 #ifdef __cpp_aligned_new
544  ,
545  std::align_val_t(Alignment)
546 #endif
547  );
548 }
549 
550 /// Deallocate a buffer of memory with the given size and alignment.
551 ///
552 /// If supported, this will used the sized delete operator. Also if supported,
553 /// this will pass the alignment to the delete operator.
554 ///
555 /// The pointer must have been allocated with the corresponding new operator,
556 /// most likely using the above helper.
557 inline void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment) {
558  ::operator delete(Ptr
559 #ifdef __cpp_sized_deallocation
560  ,
561  Size
562 #endif
563 #ifdef __cpp_aligned_new
564  ,
565  std::align_val_t(Alignment)
566 #endif
567  );
568 }
569 
570 } // End namespace llvm
571 
572 #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
void * allocate_buffer(size_t Size, size_t Alignment)
Allocate a buffer of memory with the given size and alignment.
Definition: Compiler.h:541
void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment)
Deallocate a buffer of memory with the given size and alignment.
Definition: Compiler.h:557
uint32_t Size
Definition: Profile.cpp:46