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v1.5.2-kernel
lib/common/compiler.h
341 строка
12 KB
Nick Terrell
[lazy] Use switch instead of indirect function calls.
22 окт 2022, 01:27
22 окт 2022, 01:27
8e43f53
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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 #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 #if defined(__GNUC__) || defined(__ICCARM__) # define FORCE_INLINE_ATTR __attribute__((always_inline)) #elif defined(_MSC_VER) # define FORCE_INLINE_ATTR __forceinline #else # define FORCE_INLINE_ATTR #endif #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. */ #if defined(_MSC_VER) # define WIN_CDECL __cdecl #else # define WIN_CDECL #endif /** * 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. */ #if defined(__GNUC__) # define UNUSED_ATTR __attribute__((unused)) #else # define UNUSED_ATTR #endif /* force no inlining */ #ifdef _MSC_VER # define FORCE_NOINLINE static __declspec(noinline) #else # if defined(__GNUC__) || defined(__ICCARM__) # define FORCE_NOINLINE static __attribute__((__noinline__)) # else # define FORCE_NOINLINE static # endif #endif /* target attribute */ #if defined(__GNUC__) || defined(__ICCARM__) # define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) #else # define TARGET_ATTRIBUTE(target) #endif /* 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 defined(NO_PREFETCH) # define PREFETCH_L1(ptr) (void)(ptr) /* disabled */ # define PREFETCH_L2(ptr) (void)(ptr) /* disabled */ #else # if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) /* _mm_prefetch() is not defined outside of x86/x64 */ # include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */ # define PREFETCH_L1(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T0) # define PREFETCH_L2(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1) # elif defined(__GNUC__) && ( (__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 #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. */ #if defined(__GNUC__) #define LIKELY(x) (__builtin_expect((x), 1)) #define UNLIKELY(x) (__builtin_expect((x), 0)) #else #define LIKELY(x) (x) #define UNLIKELY(x) (x) #endif #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 */ #ifdef _MSC_VER /* Visual Studio */ # include <intrin.h> /* For Visual 2005 */ # pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */ # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */ # pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */ # pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */ # pragma warning(disable : 4324) /* disable: C4324: padded structure */ #endif /*Like DYNAMIC_BMI2 but for compile time determination of BMI2 support*/ #ifndef STATIC_BMI2 # if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) # ifdef __AVX2__ //MSVC does not have a BMI2 specific flag, but every CPU that supports AVX2 also supports BMI2 # define STATIC_BMI2 1 # endif # endif #endif #ifndef STATIC_BMI2 #define STATIC_BMI2 0 #endif /* compile time determination of SIMD support */ #if !defined(ZSTD_NO_INTRINSICS) # if defined(__SSE2__) || defined(_M_AMD64) || (defined (_M_IX86) && defined(_M_IX86_FP) && (_M_IX86_FP >= 2)) # define ZSTD_ARCH_X86_SSE2 # endif # if defined(__ARM_NEON) || defined(_M_ARM64) # define ZSTD_ARCH_ARM_NEON # endif # # if defined(ZSTD_ARCH_X86_SSE2) # include <emmintrin.h> # elif defined(ZSTD_ARCH_ARM_NEON) # include <arm_neon.h> # endif #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. */ #if defined(__cplusplus) && defined(__has_cpp_attribute) # define ZSTD_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x) #else # define ZSTD_HAS_CPP_ATTRIBUTE(x) 0 #endif /* 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__)) */ #ifndef ZSTD_FALLTHROUGH # if ZSTD_HAS_C_ATTRIBUTE(fallthrough) # define ZSTD_FALLTHROUGH [[fallthrough]] # elif ZSTD_HAS_CPP_ATTRIBUTE(fallthrough) # define ZSTD_FALLTHROUGH [[fallthrough]] # elif __has_attribute(__fallthrough__) /* Leading semicolon is to satisfy gcc-11 with -pedantic. Without the semicolon * gcc complains about: a label can only be part of a statement and a declaration is not a statement. */ # define ZSTD_FALLTHROUGH ; __attribute__((__fallthrough__)) # else # define ZSTD_FALLTHROUGH # endif #endif /*-************************************************************** * 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 # if defined(__GNUC__) || defined(_MSC_VER) /* 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) # elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 support */ # include <stdalign.h> # define ZSTD_ALIGNOF(T) alignof(T) # else /* No known support for alignof() - imperfect backup */ # define ZSTD_ALIGNOF(T) (sizeof(void*) < sizeof(T) ? sizeof(void*) : sizeof(T)) # endif #endif /* ZSTD_ALIGNOF */ /*-************************************************************** * Sanitizer *****************************************************************/ #if ZSTD_MEMORY_SANITIZER /* Not all platforms that support msan provide sanitizers/msan_interface.h. * We therefore declare the functions we need ourselves, rather than trying to * include the header file... */ #include <stddef.h> /* size_t */ #define ZSTD_DEPS_NEED_STDINT #include "zstd_deps.h" /* intptr_t */ /* Make memory region fully initialized (without changing its contents). */ void __msan_unpoison(const volatile void *a, size_t size); /* Make memory region fully uninitialized (without changing its contents). This is a legacy interface that does not update origin information. Use __msan_allocated_memory() instead. */ void __msan_poison(const volatile void *a, size_t size); /* Returns the offset of the first (at least partially) poisoned byte in the memory range, or -1 if the whole range is good. */ intptr_t __msan_test_shadow(const volatile void *x, size_t size); #endif #if ZSTD_ADDRESS_SANITIZER /* Not all platforms that support asan provide sanitizers/asan_interface.h. * We therefore declare the functions we need ourselves, rather than trying to * include the header file... */ #include <stddef.h> /* size_t */ /** * Marks a memory region (<c>[addr, addr+size)</c>) as unaddressable. * * This memory must be previously allocated by your program. Instrumented * code is forbidden from accessing addresses in this region until it is * unpoisoned. This function is not guaranteed to poison the entire region - * it could poison only a subregion of <c>[addr, addr+size)</c> due to ASan * alignment restrictions. * * \note This function is not thread-safe because no two threads can poison or * unpoison memory in the same memory region simultaneously. * * \param addr Start of memory region. * \param size Size of memory region. */ void __asan_poison_memory_region(void const volatile *addr, size_t size); /** * Marks a memory region (<c>[addr, addr+size)</c>) as addressable. * * This memory must be previously allocated by your program. Accessing * addresses in this region is allowed until this region is poisoned again. * This function could unpoison a super-region of <c>[addr, addr+size)</c> due * to ASan alignment restrictions. * * \note This function is not thread-safe because no two threads can * poison or unpoison memory in the same memory region simultaneously. * * \param addr Start of memory region. * \param size Size of memory region. */ void __asan_unpoison_memory_region(void const volatile *addr, size_t size); #endif #endif /* ZSTD_COMPILER_H */