/* * 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 #include "portability_macros.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 explicitly 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 */#define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) /* Target attribute for BMI2 dynamic dispatch. * Enable lzcnt, bmi, and bmi2. * We test for bmi1 & bmi2. lzcnt is included in bmi1. */#define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2") /* 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, * and some compilers, like Intel ICC and MCST LCC, do not support it at all. */#if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) && !defined(__LCC__)#  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)) #if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)))#  define ZSTD_UNREACHABLE { assert(0), __builtin_unreachable(); }#else#  define ZSTD_UNREACHABLE { assert(0); }#endif /* disable warnings */ /*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/  /* compile time determination of SIMD support */ /* 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 /*-***************************************************************  Alignment check*****************************************************************/ /* this test was initially positioned in mem.h, * but this file is removed (or replaced) for linux kernel * so it's now hosted in compiler.h, * which remains valid for both user & kernel spaces. */ #ifndef ZSTD_ALIGNOF/* covers gcc, clang & MSVC *//* note : this section must come first, before C11, * due to a limitation in the kernel source generator */#  define ZSTD_ALIGNOF(T) __alignof(T) #endif /* ZSTD_ALIGNOF */ /*-***************************************************************  Sanitizer*****************************************************************/   #endif /* ZSTD_COMPILER_H */