diff options
Diffstat (limited to 'lib/zstd/common/compiler.h')
| -rw-r--r-- | lib/zstd/common/compiler.h | 212 |
1 files changed, 162 insertions, 50 deletions
diff --git a/lib/zstd/common/compiler.h b/lib/zstd/common/compiler.h index f5a9c70a228a..dc9bd15e174e 100644 --- a/lib/zstd/common/compiler.h +++ b/lib/zstd/common/compiler.h @@ -1,5 +1,6 @@ +/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */ /* - * Copyright (c) Yann Collet, Facebook, Inc. + * Copyright (c) Meta Platforms, Inc. and affiliates. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the @@ -11,6 +12,10 @@ #ifndef ZSTD_COMPILER_H #define ZSTD_COMPILER_H +#include <linux/types.h> + +#include "portability_macros.h" + /*-******************************************************* * Compiler specifics *********************************************************/ @@ -34,17 +39,20 @@ /* 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 + 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 +/* UNUSED_ATTR tells the compiler it is okay if the function is unused. */ +#define UNUSED_ATTR __attribute__((unused)) + /* * 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 +#define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR UNUSED_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 @@ -59,36 +67,34 @@ #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 +# define HINT_INLINE FORCE_INLINE_TEMPLATE #endif -/* UNUSED_ATTR tells the compiler it is okay if the function is unused. */ -#define UNUSED_ATTR __attribute__((unused)) +/* "soft" inline : + * The compiler is free to select if it's a good idea to inline or not. + * The main objective is to silence compiler warnings + * when a defined function in included but not used. + * + * Note : this macro is prefixed `MEM_` because it used to be provided by `mem.h` unit. + * Updating the prefix is probably preferable, but requires a fairly large codemod, + * since this name is used everywhere. + */ +#ifndef MEM_STATIC /* already defined in Linux Kernel mem.h */ +#define MEM_STATIC static __inline UNUSED_ATTR +#endif /* 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. +/* Target attribute for BMI2 dynamic dispatch. + * Enable lzcnt, bmi, and bmi2. + * We test for bmi1 & bmi2. lzcnt is included in bmi1. */ -#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 +#define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2") /* prefetch * can be disabled, by declaring NO_PREFETCH build macro */ @@ -96,27 +102,29 @@ # 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))) +# define PREFETCH_L1(ptr) do { __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))); } while (0) +# define PREFETCH_L2(ptr) do { __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))); } while (0) #else -# define PREFETCH_L1(ptr) (void)(ptr) /* disabled */ -# define PREFETCH_L2(ptr) (void)(ptr) /* disabled */ +# define PREFETCH_L1(ptr) do { (void)(ptr); } while (0) /* disabled */ +# define PREFETCH_L2(ptr) do { (void)(ptr); } while (0) /* 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); \ - } \ -} +#define PREFETCH_AREA(p, s) \ + do { \ + 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); \ + } \ + } while (0) /* vectorization - * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax */ -#if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) + * 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 @@ -134,20 +142,15 @@ #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 +#if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))) +# define ZSTD_UNREACHABLE do { assert(0), __builtin_unreachable(); } while (0) +#else +# define ZSTD_UNREACHABLE do { assert(0); } while (0) #endif -/* compat. with non-clang compilers */ -#ifndef __has_feature -# define __has_feature(x) 0 -#endif +/* disable warnings */ + +/* compile time determination of SIMD support */ /* C-language Attributes are added in C23. */ #if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute) @@ -168,10 +171,119 @@ */ #define ZSTD_FALLTHROUGH fallthrough -/* detects whether we are being compiled under msan */ +/*-************************************************************** +* Alignment +*****************************************************************/ + +/* @return 1 if @u is a 2^n value, 0 otherwise + * useful to check a value is valid for alignment restrictions */ +MEM_STATIC int ZSTD_isPower2(size_t u) { + return (u & (u-1)) == 0; +} + +/* 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 */ + +#ifndef ZSTD_ALIGNED +/* C90-compatible alignment macro (GCC/Clang). Adjust for other compilers if needed. */ +#define ZSTD_ALIGNED(a) __attribute__((aligned(a))) +#endif /* ZSTD_ALIGNED */ + + +/*-************************************************************** +* Sanitizer +*****************************************************************/ +/* + * Zstd relies on pointer overflow in its decompressor. + * We add this attribute to functions that rely on pointer overflow. + */ +#ifndef ZSTD_ALLOW_POINTER_OVERFLOW_ATTR +# if __has_attribute(no_sanitize) +# if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 8 + /* gcc < 8 only has signed-integer-overlow which triggers on pointer overflow */ +# define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR __attribute__((no_sanitize("signed-integer-overflow"))) +# else + /* older versions of clang [3.7, 5.0) will warn that pointer-overflow is ignored. */ +# define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR __attribute__((no_sanitize("pointer-overflow"))) +# endif +# else +# define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR +# endif +#endif + +/* + * Helper function to perform a wrapped pointer difference without triggering + * UBSAN. + * + * @returns lhs - rhs with wrapping + */ +MEM_STATIC +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR +ptrdiff_t ZSTD_wrappedPtrDiff(unsigned char const* lhs, unsigned char const* rhs) +{ + return lhs - rhs; +} + +/* + * Helper function to perform a wrapped pointer add without triggering UBSAN. + * + * @return ptr + add with wrapping + */ +MEM_STATIC +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR +unsigned char const* ZSTD_wrappedPtrAdd(unsigned char const* ptr, ptrdiff_t add) +{ + return ptr + add; +} + +/* + * Helper function to perform a wrapped pointer subtraction without triggering + * UBSAN. + * + * @return ptr - sub with wrapping + */ +MEM_STATIC +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR +unsigned char const* ZSTD_wrappedPtrSub(unsigned char const* ptr, ptrdiff_t sub) +{ + return ptr - sub; +} + +/* + * Helper function to add to a pointer that works around C's undefined behavior + * of adding 0 to NULL. + * + * @returns `ptr + add` except it defines `NULL + 0 == NULL`. + */ +MEM_STATIC +unsigned char* ZSTD_maybeNullPtrAdd(unsigned char* ptr, ptrdiff_t add) +{ + return add > 0 ? ptr + add : ptr; +} + +/* Issue #3240 reports an ASAN failure on an llvm-mingw build. Out of an + * abundance of caution, disable our custom poisoning on mingw. */ +#ifdef __MINGW32__ +#ifndef ZSTD_ASAN_DONT_POISON_WORKSPACE +#define ZSTD_ASAN_DONT_POISON_WORKSPACE 1 +#endif +#ifndef ZSTD_MSAN_DONT_POISON_WORKSPACE +#define ZSTD_MSAN_DONT_POISON_WORKSPACE 1 +#endif +#endif -/* detects whether we are being compiled under asan */ #endif /* ZSTD_COMPILER_H */ |