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compiler.h
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1/*
2 * Copyright (c) Meta Platforms, Inc. and affiliates.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11#ifndef ZSTD_COMPILER_H
12#define ZSTD_COMPILER_H
13
14#include <stddef.h>
15
16#include "portability_macros.h"
17
18/*-*******************************************************
19* Compiler specifics
20*********************************************************/
21/* force inlining */
22
23#if !defined(ZSTD_NO_INLINE)
24#if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */
25# define INLINE_KEYWORD inline
26#else
27# define INLINE_KEYWORD
28#endif
29
30#if defined(__GNUC__) || defined(__ICCARM__)
31# define FORCE_INLINE_ATTR __attribute__((always_inline))
32#elif defined(_MSC_VER)
33# define FORCE_INLINE_ATTR __forceinline
34#else
35# define FORCE_INLINE_ATTR
36#endif
37
38#else
39
40#define INLINE_KEYWORD
41#define FORCE_INLINE_ATTR
42
43#endif
44
50#if defined(_MSC_VER)
51# define WIN_CDECL __cdecl
52#else
53# define WIN_CDECL
54#endif
55
56/* UNUSED_ATTR tells the compiler it is okay if the function is unused. */
57#if defined(__GNUC__)
58# define UNUSED_ATTR __attribute__((unused))
59#else
60# define UNUSED_ATTR
61#endif
62
68#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR UNUSED_ATTR
80#if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5
81# define HINT_INLINE static INLINE_KEYWORD
82#else
83# define HINT_INLINE FORCE_INLINE_TEMPLATE
84#endif
85
86/* "soft" inline :
87 * The compiler is free to select if it's a good idea to inline or not.
88 * The main objective is to silence compiler warnings
89 * when a defined function in included but not used.
90 *
91 * Note : this macro is prefixed `MEM_` because it used to be provided by `mem.h` unit.
92 * Updating the prefix is probably preferable, but requires a fairly large codemod,
93 * since this name is used everywhere.
94 */
95#ifndef MEM_STATIC /* already defined in Linux Kernel mem.h */
96#if defined(__GNUC__)
97# define MEM_STATIC static __inline UNUSED_ATTR
98#elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
99# define MEM_STATIC static inline
100#elif defined(_MSC_VER)
101# define MEM_STATIC static __inline
102#else
103# define MEM_STATIC static /* this version may generate warnings for unused static functions; disable the relevant warning */
104#endif
105#endif
106
107/* force no inlining */
108#ifdef _MSC_VER
109# define FORCE_NOINLINE static __declspec(noinline)
110#else
111# if defined(__GNUC__) || defined(__ICCARM__)
112# define FORCE_NOINLINE static __attribute__((__noinline__))
113# else
114# define FORCE_NOINLINE static
115# endif
116#endif
117
118
119/* target attribute */
120#if defined(__GNUC__) || defined(__ICCARM__)
121# define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
122#else
123# define TARGET_ATTRIBUTE(target)
124#endif
125
126/* Target attribute for BMI2 dynamic dispatch.
127 * Enable lzcnt, bmi, and bmi2.
128 * We test for bmi1 & bmi2. lzcnt is included in bmi1.
129 */
130#define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2")
131
132/* prefetch
133 * can be disabled, by declaring NO_PREFETCH build macro */
134#if defined(NO_PREFETCH)
135# define PREFETCH_L1(ptr) do { (void)(ptr); } while (0) /* disabled */
136# define PREFETCH_L2(ptr) do { (void)(ptr); } while (0) /* disabled */
137#else
138# if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) && !defined(_M_ARM64EC) /* _mm_prefetch() is not defined outside of x86/x64 */
139# include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
140# define PREFETCH_L1(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T0)
141# define PREFETCH_L2(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1)
142# elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )
143# define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */)
144# define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)
145# elif defined(__aarch64__)
146# define PREFETCH_L1(ptr) do { __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))); } while (0)
147# define PREFETCH_L2(ptr) do { __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))); } while (0)
148# else
149# define PREFETCH_L1(ptr) do { (void)(ptr); } while (0) /* disabled */
150# define PREFETCH_L2(ptr) do { (void)(ptr); } while (0) /* disabled */
151# endif
152#endif /* NO_PREFETCH */
153
154#define CACHELINE_SIZE 64
155
156#define PREFETCH_AREA(p, s) \
157 do { \
158 const char* const _ptr = (const char*)(p); \
159 size_t const _size = (size_t)(s); \
160 size_t _pos; \
161 for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \
162 PREFETCH_L2(_ptr + _pos); \
163 } \
164 } while (0)
165
166/* vectorization
167 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax,
168 * and some compilers, like Intel ICC and MCST LCC, do not support it at all. */
169#if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) && !defined(__LCC__)
170# if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5)
171# define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize")))
172# else
173# define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")")
174# endif
175#else
176# define DONT_VECTORIZE
177#endif
178
179/* Tell the compiler that a branch is likely or unlikely.
180 * Only use these macros if it causes the compiler to generate better code.
181 * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc
182 * and clang, please do.
183 */
184#if defined(__GNUC__)
185#define LIKELY(x) (__builtin_expect((x), 1))
186#define UNLIKELY(x) (__builtin_expect((x), 0))
187#else
188#define LIKELY(x) (x)
189#define UNLIKELY(x) (x)
190#endif
191
192#if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)))
193# define ZSTD_UNREACHABLE do { assert(0), __builtin_unreachable(); } while (0)
194#else
195# define ZSTD_UNREACHABLE do { assert(0); } while (0)
196#endif
197
198/* disable warnings */
199#ifdef _MSC_VER /* Visual Studio */
200# include <intrin.h> /* For Visual 2005 */
201# pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */
202# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
203# pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */
204# pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */
205# pragma warning(disable : 4324) /* disable: C4324: padded structure */
206#endif
207
208/*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/
209#ifndef STATIC_BMI2
210# if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86))
211# ifdef __AVX2__ //MSVC does not have a BMI2 specific flag, but every CPU that supports AVX2 also supports BMI2
212# define STATIC_BMI2 1
213# endif
214# elif defined(__BMI2__) && defined(__x86_64__) && defined(__GNUC__)
215# define STATIC_BMI2 1
216# endif
217#endif
218
219#ifndef STATIC_BMI2
220 #define STATIC_BMI2 0
221#endif
222
223/* compile time determination of SIMD support */
224#if !defined(ZSTD_NO_INTRINSICS)
225# if defined(__SSE2__) || defined(_M_AMD64) || (defined (_M_IX86) && defined(_M_IX86_FP) && (_M_IX86_FP >= 2))
226# define ZSTD_ARCH_X86_SSE2
227# endif
228# if defined(__ARM_NEON) || defined(_M_ARM64)
229# define ZSTD_ARCH_ARM_NEON
230# endif
231#
232# if defined(ZSTD_ARCH_X86_SSE2)
233# include <emmintrin.h>
234# elif defined(ZSTD_ARCH_ARM_NEON)
235# include <arm_neon.h>
236# endif
237#endif
238
239/* C-language Attributes are added in C23. */
240#if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute)
241# define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x)
242#else
243# define ZSTD_HAS_C_ATTRIBUTE(x) 0
244#endif
245
246/* Only use C++ attributes in C++. Some compilers report support for C++
247 * attributes when compiling with C.
248 */
249#if defined(__cplusplus) && defined(__has_cpp_attribute)
250# define ZSTD_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
251#else
252# define ZSTD_HAS_CPP_ATTRIBUTE(x) 0
253#endif
254
255/* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute.
256 * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough
257 * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough
258 * - Else: __attribute__((__fallthrough__))
259 */
260#ifndef ZSTD_FALLTHROUGH
261# if ZSTD_HAS_C_ATTRIBUTE(fallthrough)
262# define ZSTD_FALLTHROUGH [[fallthrough]]
263# elif ZSTD_HAS_CPP_ATTRIBUTE(fallthrough)
264# define ZSTD_FALLTHROUGH [[fallthrough]]
265# elif __has_attribute(__fallthrough__)
266/* Leading semicolon is to satisfy gcc-11 with -pedantic. Without the semicolon
267 * gcc complains about: a label can only be part of a statement and a declaration is not a statement.
268 */
269# define ZSTD_FALLTHROUGH ; __attribute__((__fallthrough__))
270# else
271# define ZSTD_FALLTHROUGH
272# endif
273#endif
274
275/*-**************************************************************
276* Alignment check
277*****************************************************************/
278
279/* this test was initially positioned in mem.h,
280 * but this file is removed (or replaced) for linux kernel
281 * so it's now hosted in compiler.h,
282 * which remains valid for both user & kernel spaces.
283 */
284
285#ifndef ZSTD_ALIGNOF
286# if defined(__GNUC__) || defined(_MSC_VER)
287/* covers gcc, clang & MSVC */
288/* note : this section must come first, before C11,
289 * due to a limitation in the kernel source generator */
290# define ZSTD_ALIGNOF(T) __alignof(T)
291
292# elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
293/* C11 support */
294# include <stdalign.h>
295# define ZSTD_ALIGNOF(T) alignof(T)
296
297# else
298/* No known support for alignof() - imperfect backup */
299# define ZSTD_ALIGNOF(T) (sizeof(void*) < sizeof(T) ? sizeof(void*) : sizeof(T))
300
301# endif
302#endif /* ZSTD_ALIGNOF */
303
304/*-**************************************************************
305* Sanitizer
306*****************************************************************/
307
312#ifndef ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
313# if __has_attribute(no_sanitize)
314# if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 8
315 /* gcc < 8 only has signed-integer-overlow which triggers on pointer overflow */
316# define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR __attribute__((no_sanitize("signed-integer-overflow")))
317# else
318 /* older versions of clang [3.7, 5.0) will warn that pointer-overflow is ignored. */
319# define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR __attribute__((no_sanitize("pointer-overflow")))
320# endif
321# else
322# define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
323# endif
324#endif
325
334ptrdiff_t ZSTD_wrappedPtrDiff(unsigned char const* lhs, unsigned char const* rhs)
335{
336 return lhs - rhs;
337}
338
346unsigned char const* ZSTD_wrappedPtrAdd(unsigned char const* ptr, ptrdiff_t add)
347{
348 return ptr + add;
349}
350
359unsigned char const* ZSTD_wrappedPtrSub(unsigned char const* ptr, ptrdiff_t sub)
360{
361 return ptr - sub;
362}
363
371unsigned char* ZSTD_maybeNullPtrAdd(unsigned char* ptr, ptrdiff_t add)
372{
373 return add > 0 ? ptr + add : ptr;
374}
375
376/* Issue #3240 reports an ASAN failure on an llvm-mingw build. Out of an
377 * abundance of caution, disable our custom poisoning on mingw. */
378#ifdef __MINGW32__
379#ifndef ZSTD_ASAN_DONT_POISON_WORKSPACE
380#define ZSTD_ASAN_DONT_POISON_WORKSPACE 1
381#endif
382#ifndef ZSTD_MSAN_DONT_POISON_WORKSPACE
383#define ZSTD_MSAN_DONT_POISON_WORKSPACE 1
384#endif
385#endif
386
387#if ZSTD_MEMORY_SANITIZER && !defined(ZSTD_MSAN_DONT_POISON_WORKSPACE)
388/* Not all platforms that support msan provide sanitizers/msan_interface.h.
389 * We therefore declare the functions we need ourselves, rather than trying to
390 * include the header file... */
391#include <stddef.h> /* size_t */
392#define ZSTD_DEPS_NEED_STDINT
393#include "zstd_deps.h" /* intptr_t */
394
395/* Make memory region fully initialized (without changing its contents). */
396void __msan_unpoison(const volatile void *a, size_t size);
397
398/* Make memory region fully uninitialized (without changing its contents).
399 This is a legacy interface that does not update origin information. Use
400 __msan_allocated_memory() instead. */
401void __msan_poison(const volatile void *a, size_t size);
402
403/* Returns the offset of the first (at least partially) poisoned byte in the
404 memory range, or -1 if the whole range is good. */
405intptr_t __msan_test_shadow(const volatile void *x, size_t size);
406
407/* Print shadow and origin for the memory range to stderr in a human-readable
408 format. */
409void __msan_print_shadow(const volatile void *x, size_t size);
410#endif
411
412#if ZSTD_ADDRESS_SANITIZER && !defined(ZSTD_ASAN_DONT_POISON_WORKSPACE)
413/* Not all platforms that support asan provide sanitizers/asan_interface.h.
414 * We therefore declare the functions we need ourselves, rather than trying to
415 * include the header file... */
416#include <stddef.h> /* size_t */
417
432void __asan_poison_memory_region(void const volatile *addr, size_t size);
433
447void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
448#endif
449
450#endif /* ZSTD_COMPILER_H */
MEM_STATIC ZSTD_ALLOW_POINTER_OVERFLOW_ATTR unsigned char const * ZSTD_wrappedPtrSub(unsigned char const *ptr, ptrdiff_t sub)
Definition: compiler.h:359
MEM_STATIC ZSTD_ALLOW_POINTER_OVERFLOW_ATTR ptrdiff_t ZSTD_wrappedPtrDiff(unsigned char const *lhs, unsigned char const *rhs)
Definition: compiler.h:334
MEM_STATIC unsigned char * ZSTD_maybeNullPtrAdd(unsigned char *ptr, ptrdiff_t add)
Definition: compiler.h:371
MEM_STATIC ZSTD_ALLOW_POINTER_OVERFLOW_ATTR unsigned char const * ZSTD_wrappedPtrAdd(unsigned char const *ptr, ptrdiff_t add)
Definition: compiler.h:346
#define MEM_STATIC
Definition: compiler.h:103
#define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
Definition: compiler.h:322