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- /*
- * Copyright (c) Yann Collet, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under both the BSD-style license (found in the
- * LICENSE file in the root directory of this source tree) and the GPLv2 (found
- * in the COPYING file in the root directory of this source tree).
- * You may select, at your option, one of the above-listed licenses.
- */
- #ifndef ZSTD_COMPILER_H
- #define ZSTD_COMPILER_H
- /*-*******************************************************
- * Compiler specifics
- *********************************************************/
- /* force inlining */
- #if !defined(ZSTD_NO_INLINE)
- #if (defined(__GNUC__) && !defined(__STRICT_ANSI__)) || defined(__cplusplus) || defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L /* C99 */
- # define INLINE_KEYWORD inline
- #else
- # define INLINE_KEYWORD
- #endif
- #define FORCE_INLINE_ATTR __attribute__((always_inline))
- #else
- #define INLINE_KEYWORD
- #define FORCE_INLINE_ATTR
- #endif
- /*
- On MSVC qsort requires that functions passed into it use the __cdecl calling conversion(CC).
- This explictly marks such functions as __cdecl so that the code will still compile
- if a CC other than __cdecl has been made the default.
- */
- #define WIN_CDECL
- /*
- * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant
- * parameters. They must be inlined for the compiler to eliminate the constant
- * branches.
- */
- #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR
- /*
- * HINT_INLINE is used to help the compiler generate better code. It is *not*
- * used for "templates", so it can be tweaked based on the compilers
- * performance.
- *
- * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the
- * always_inline attribute.
- *
- * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline
- * attribute.
- */
- #if !defined(__clang__) && defined(__GNUC__) && __GNUC__ >= 4 && __GNUC_MINOR__ >= 8 && __GNUC__ < 5
- # define HINT_INLINE static INLINE_KEYWORD
- #else
- # define HINT_INLINE static INLINE_KEYWORD FORCE_INLINE_ATTR
- #endif
- /* UNUSED_ATTR tells the compiler it is okay if the function is unused. */
- #define UNUSED_ATTR __attribute__((unused))
- /* force no inlining */
- #define FORCE_NOINLINE static __attribute__((__noinline__))
- /* target attribute */
- #ifndef __has_attribute
- #define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
- #endif
- #define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
- /* Enable runtime BMI2 dispatch based on the CPU.
- * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
- */
- #ifndef DYNAMIC_BMI2
- #if ((defined(__clang__) && __has_attribute(__target__)) \
- || (defined(__GNUC__) \
- && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))) \
- && (defined(__x86_64__) || defined(_M_X86)) \
- && !defined(__BMI2__)
- # define DYNAMIC_BMI2 1
- #else
- # define DYNAMIC_BMI2 0
- #endif
- #endif
- /* prefetch
- * can be disabled, by declaring NO_PREFETCH build macro */
- #if ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )
- # define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */)
- # define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */)
- #elif defined(__aarch64__)
- # define PREFETCH_L1(ptr) __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr)))
- # define PREFETCH_L2(ptr) __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr)))
- #else
- # define PREFETCH_L1(ptr) (void)(ptr) /* disabled */
- # define PREFETCH_L2(ptr) (void)(ptr) /* disabled */
- #endif /* NO_PREFETCH */
- #define CACHELINE_SIZE 64
- #define PREFETCH_AREA(p, s) { \
- const char* const _ptr = (const char*)(p); \
- size_t const _size = (size_t)(s); \
- size_t _pos; \
- for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \
- PREFETCH_L2(_ptr + _pos); \
- } \
- }
- /* vectorization
- * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax */
- #if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__)
- # if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5)
- # define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize")))
- # else
- # define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")")
- # endif
- #else
- # define DONT_VECTORIZE
- #endif
- /* Tell the compiler that a branch is likely or unlikely.
- * Only use these macros if it causes the compiler to generate better code.
- * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc
- * and clang, please do.
- */
- #define LIKELY(x) (__builtin_expect((x), 1))
- #define UNLIKELY(x) (__builtin_expect((x), 0))
- /* disable warnings */
- /*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/
- /* compat. with non-clang compilers */
- #ifndef __has_builtin
- # define __has_builtin(x) 0
- #endif
- /* compat. with non-clang compilers */
- #ifndef __has_feature
- # define __has_feature(x) 0
- #endif
- /* C-language Attributes are added in C23. */
- #if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute)
- # define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x)
- #else
- # define ZSTD_HAS_C_ATTRIBUTE(x) 0
- #endif
- /* Only use C++ attributes in C++. Some compilers report support for C++
- * attributes when compiling with C.
- */
- #define ZSTD_HAS_CPP_ATTRIBUTE(x) 0
- /* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute.
- * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough
- * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough
- * - Else: __attribute__((__fallthrough__))
- */
- #define ZSTD_FALLTHROUGH fallthrough
- /* detects whether we are being compiled under msan */
- /* detects whether we are being compiled under asan */
- #endif /* ZSTD_COMPILER_H */
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