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 /// * 1910: VS2017, version 15.1 & 15.2
66 /// * 1911: VS2017, version 15.3 & 15.4
67 /// * 1912: VS2017, version 15.5
68 /// * 1913: VS2017, version 15.6
69 /// * 1914: VS2017, version 15.7
70 /// * 1915: VS2017, version 15.8
71 /// * 1916: VS2017, version 15.9
72 /// * 1920: VS2019, version 16.0
73 /// * 1921: VS2019, version 16.1
74 #ifdef _MSC_VER
75 #define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version))
76 
77 // We require at least MSVC 2017.
78 #if !LLVM_MSC_PREREQ(1910)
79 #error LLVM requires at least MSVC 2017.
80 #endif
81 
82 #else
83 #define LLVM_MSC_PREREQ(version) 0
84 #endif
85 
86 /// Does the compiler support ref-qualifiers for *this?
87 ///
88 /// Sadly, this is separate from just rvalue reference support because GCC
89 /// and MSVC implemented this later than everything else.
90 #if __has_feature(cxx_rvalue_references) || LLVM_GNUC_PREREQ(4, 8, 1)
91 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1
92 #else
93 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0
94 #endif
95 
96 /// Expands to '&' if ref-qualifiers for *this are supported.
97 ///
98 /// This can be used to provide lvalue/rvalue overrides of member functions.
99 /// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
100 #if LLVM_HAS_RVALUE_REFERENCE_THIS
101 #define LLVM_LVALUE_FUNCTION &
102 #else
103 #define LLVM_LVALUE_FUNCTION
104 #endif
105 
106 /// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked
107 /// into a shared library, then the class should be private to the library and
108 /// not accessible from outside it. Can also be used to mark variables and
109 /// functions, making them private to any shared library they are linked into.
110 /// On PE/COFF targets, library visibility is the default, so this isn't needed.
111 #if (__has_attribute(visibility) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
112  !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32)
113 #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
114 #else
115 #define LLVM_LIBRARY_VISIBILITY
116 #endif
117 
118 #if defined(__GNUC__)
119 #define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality)
120 #else
121 #define LLVM_PREFETCH(addr, rw, locality)
122 #endif
123 
124 #if __has_attribute(used) || LLVM_GNUC_PREREQ(3, 1, 0)
125 #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
126 #else
127 #define LLVM_ATTRIBUTE_USED
128 #endif
129 
130 /// LLVM_NODISCARD - Warn if a type or return value is discarded.
131 #if __cplusplus > 201402L && __has_cpp_attribute(nodiscard)
132 #define LLVM_NODISCARD [[nodiscard]]
133 #elif !__cplusplus
134 // Workaround for llvm.org/PR23435, since clang 3.6 and below emit a spurious
135 // error when __has_cpp_attribute is given a scoped attribute in C mode.
136 #define LLVM_NODISCARD
137 #elif __has_cpp_attribute(clang::warn_unused_result)
138 #define LLVM_NODISCARD [[clang::warn_unused_result]]
139 #else
140 #define LLVM_NODISCARD
141 #endif
142 
143 // Indicate that a non-static, non-const C++ member function reinitializes
144 // the entire object to a known state, independent of the previous state of
145 // the object.
146 //
147 // The clang-tidy check bugprone-use-after-move recognizes this attribute as a
148 // marker that a moved-from object has left the indeterminate state and can be
149 // reused.
150 #if __has_cpp_attribute(clang::reinitializes)
151 #define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]]
152 #else
153 #define LLVM_ATTRIBUTE_REINITIALIZES
154 #endif
155 
156 // Some compilers warn about unused functions. When a function is sometimes
157 // used or not depending on build settings (e.g. a function only called from
158 // within "assert"), this attribute can be used to suppress such warnings.
159 //
160 // However, it shouldn't be used for unused *variables*, as those have a much
161 // more portable solution:
162 // (void)unused_var_name;
163 // Prefer cast-to-void wherever it is sufficient.
164 #if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0)
165 #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
166 #else
167 #define LLVM_ATTRIBUTE_UNUSED
168 #endif
169 
170 // FIXME: Provide this for PE/COFF targets.
171 #if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) && \
172  (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32))
173 #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
174 #else
175 #define LLVM_ATTRIBUTE_WEAK
176 #endif
177 
178 // Prior to clang 3.2, clang did not accept any spelling of
179 // __has_attribute(const), so assume it is supported.
180 #if defined(__clang__) || defined(__GNUC__)
181 // aka 'CONST' but following LLVM Conventions.
182 #define LLVM_READNONE __attribute__((__const__))
183 #else
184 #define LLVM_READNONE
185 #endif
186 
187 #if __has_attribute(pure) || defined(__GNUC__)
188 // aka 'PURE' but following LLVM Conventions.
189 #define LLVM_READONLY __attribute__((__pure__))
190 #else
191 #define LLVM_READONLY
192 #endif
193 
194 #if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0)
195 #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
196 #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
197 #else
198 #define LLVM_LIKELY(EXPR) (EXPR)
199 #define LLVM_UNLIKELY(EXPR) (EXPR)
200 #endif
201 
202 /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so,
203 /// mark a method "not for inlining".
204 #if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0)
205 #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
206 #elif defined(_MSC_VER)
207 #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
208 #else
209 #define LLVM_ATTRIBUTE_NOINLINE
210 #endif
211 
212 /// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do
213 /// so, mark a method "always inline" because it is performance sensitive. GCC
214 /// 3.4 supported this but is buggy in various cases and produces unimplemented
215 /// errors, just use it in GCC 4.0 and later.
216 #if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0)
217 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
218 #elif defined(_MSC_VER)
219 #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
220 #else
221 #define LLVM_ATTRIBUTE_ALWAYS_INLINE
222 #endif
223 
224 #ifdef __GNUC__
225 #define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn))
226 #elif defined(_MSC_VER)
227 #define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn)
228 #else
229 #define LLVM_ATTRIBUTE_NORETURN
230 #endif
231 
232 #if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0)
233 #define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull))
234 #elif defined(_MSC_VER)
235 #define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_
236 #else
237 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
238 #endif
239 
240 /// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
241 /// pointer that does not alias any other valid pointer.
242 #ifdef __GNUC__
243 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
244 #elif defined(_MSC_VER)
245 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
246 #else
247 #define LLVM_ATTRIBUTE_RETURNS_NOALIAS
248 #endif
249 
250 /// LLVM_FALLTHROUGH - Mark fallthrough cases in switch statements.
251 #if __cplusplus > 201402L && __has_cpp_attribute(fallthrough)
252 #define LLVM_FALLTHROUGH [[fallthrough]]
253 #elif __has_cpp_attribute(gnu::fallthrough)
254 #define LLVM_FALLTHROUGH [[gnu::fallthrough]]
255 #elif !__cplusplus
256 // Workaround for llvm.org/PR23435, since clang 3.6 and below emit a spurious
257 // error when __has_cpp_attribute is given a scoped attribute in C mode.
258 #define LLVM_FALLTHROUGH
259 #elif __has_cpp_attribute(clang::fallthrough)
260 #define LLVM_FALLTHROUGH [[clang::fallthrough]]
261 #else
262 #define LLVM_FALLTHROUGH
263 #endif
264 
265 /// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that
266 /// they are constant initialized.
267 #if __has_cpp_attribute(clang::require_constant_initialization)
268 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION \
269  [[clang::require_constant_initialization]]
270 #else
271 #define LLVM_REQUIRE_CONSTANT_INITIALIZATION
272 #endif
273 
274 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
275 /// pedantic diagnostics.
276 #ifdef __GNUC__
277 #define LLVM_EXTENSION __extension__
278 #else
279 #define LLVM_EXTENSION
280 #endif
281 
282 // LLVM_ATTRIBUTE_DEPRECATED(decl, "message")
283 #if __has_feature(attribute_deprecated_with_message)
284 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
285  decl __attribute__((deprecated(message)))
286 #elif defined(__GNUC__)
287 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
288  decl __attribute__((deprecated))
289 #elif defined(_MSC_VER)
290 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
291  __declspec(deprecated(message)) decl
292 #else
293 # define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \
294  decl
295 #endif
296 
297 /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
298 /// to an expression which states that it is undefined behavior for the
299 /// compiler to reach this point. Otherwise is not defined.
300 #if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0)
301 # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
302 #elif defined(_MSC_VER)
303 # define LLVM_BUILTIN_UNREACHABLE __assume(false)
304 #endif
305 
306 /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression
307 /// which causes the program to exit abnormally.
308 #if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0)
309 # define LLVM_BUILTIN_TRAP __builtin_trap()
310 #elif defined(_MSC_VER)
311 // The __debugbreak intrinsic is supported by MSVC, does not require forward
312 // declarations involving platform-specific typedefs (unlike RaiseException),
313 // results in a call to vectored exception handlers, and encodes to a short
314 // instruction that still causes the trapping behavior we want.
315 # define LLVM_BUILTIN_TRAP __debugbreak()
316 #else
317 # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
318 #endif
319 
320 /// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to
321 /// an expression which causes the program to break while running
322 /// under a debugger.
323 #if __has_builtin(__builtin_debugtrap)
324 # define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap()
325 #elif defined(_MSC_VER)
326 // The __debugbreak intrinsic is supported by MSVC and breaks while
327 // running under the debugger, and also supports invoking a debugger
328 // when the OS is configured appropriately.
329 # define LLVM_BUILTIN_DEBUGTRAP __debugbreak()
330 #else
331 // Just continue execution when built with compilers that have no
332 // support. This is a debugging aid and not intended to force the
333 // program to abort if encountered.
334 # define LLVM_BUILTIN_DEBUGTRAP
335 #endif
336 
337 /// \macro LLVM_ASSUME_ALIGNED
338 /// Returns a pointer with an assumed alignment.
339 #if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0)
340 # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
341 #elif defined(LLVM_BUILTIN_UNREACHABLE)
342 // As of today, clang does not support __builtin_assume_aligned.
343 # define LLVM_ASSUME_ALIGNED(p, a) \
344  (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
345 #else
346 # define LLVM_ASSUME_ALIGNED(p, a) (p)
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 alignas or when doing computation in the
380 /// 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