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 45 /** 46 On MSVC qsort requires that functions passed into it use the __cdecl calling conversion(CC). 47 This explicitly marks such functions as __cdecl so that the code will still compile 48 if a CC other than __cdecl has been made the default. 49 */ 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 63 /** 64 * FORCE_INLINE_TEMPLATE is used to define C "templates", which take constant 65 * parameters. They must be inlined for the compiler to eliminate the constant 66 * branches. 67 */ 68 #define FORCE_INLINE_TEMPLATE static INLINE_KEYWORD FORCE_INLINE_ATTR UNUSED_ATTR 69 /** 70 * HINT_INLINE is used to help the compiler generate better code. It is *not* 71 * used for "templates", so it can be tweaked based on the compilers 72 * performance. 73 * 74 * gcc-4.8 and gcc-4.9 have been shown to benefit from leaving off the 75 * always_inline attribute. 76 * 77 * clang up to 5.0.0 (trunk) benefit tremendously from the always_inline 78 * attribute. 79 */ 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 *****************************************************************/ 307 308 /** 309 * Zstd relies on pointer overflow in its decompressor. 310 * We add this attribute to functions that rely on pointer overflow. 311 */ 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 325 326 /** 327 * Helper function to perform a wrapped pointer difference without trigging 328 * UBSAN. 329 * 330 * @returns lhs - rhs with wrapping 331 */ 332 MEM_STATIC 333 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 334 ptrdiff_t ZSTD_wrappedPtrDiff(unsigned char const* lhs, unsigned char const* rhs) 335 { 336 return lhs - rhs; 337 } 338 339 /** 340 * Helper function to perform a wrapped pointer add without triggering UBSAN. 341 * 342 * @return ptr + add with wrapping 343 */ 344 MEM_STATIC 345 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 346 unsigned char const* ZSTD_wrappedPtrAdd(unsigned char const* ptr, ptrdiff_t add) 347 { 348 return ptr + add; 349 } 350 351 /** 352 * Helper function to perform a wrapped pointer subtraction without triggering 353 * UBSAN. 354 * 355 * @return ptr - sub with wrapping 356 */ 357 MEM_STATIC 358 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 359 unsigned char const* ZSTD_wrappedPtrSub(unsigned char const* ptr, ptrdiff_t sub) 360 { 361 return ptr - sub; 362 } 363 364 /** 365 * Helper function to add to a pointer that works around C's undefined behavior 366 * of adding 0 to NULL. 367 * 368 * @returns `ptr + add` except it defines `NULL + 0 == NULL`. 369 */ 370 MEM_STATIC 371 unsigned 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). */ 396 void __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. */ 401 void __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. */ 405 intptr_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. */ 409 void __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 */ 417 418 /** 419 * Marks a memory region (<c>[addr, addr+size)</c>) as unaddressable. 420 * 421 * This memory must be previously allocated by your program. Instrumented 422 * code is forbidden from accessing addresses in this region until it is 423 * unpoisoned. This function is not guaranteed to poison the entire region - 424 * it could poison only a subregion of <c>[addr, addr+size)</c> due to ASan 425 * alignment restrictions. 426 * 427 * \note This function is not thread-safe because no two threads can poison or 428 * unpoison memory in the same memory region simultaneously. 429 * 430 * \param addr Start of memory region. 431 * \param size Size of memory region. */ 432 void __asan_poison_memory_region(void const volatile *addr, size_t size); 433 434 /** 435 * Marks a memory region (<c>[addr, addr+size)</c>) as addressable. 436 * 437 * This memory must be previously allocated by your program. Accessing 438 * addresses in this region is allowed until this region is poisoned again. 439 * This function could unpoison a super-region of <c>[addr, addr+size)</c> due 440 * to ASan alignment restrictions. 441 * 442 * \note This function is not thread-safe because no two threads can 443 * poison or unpoison memory in the same memory region simultaneously. 444 * 445 * \param addr Start of memory region. 446 * \param size Size of memory region. */ 447 void __asan_unpoison_memory_region(void const volatile *addr, size_t size); 448 #endif 449 450 #endif /* ZSTD_COMPILER_H */ 451
Indexes created Tue Feb 24 08:35:24 UTC 2026