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(__IAR_SYSTEMS_ICC__) 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__) || defined(__IAR_SYSTEMS_ICC__) 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(__IAR_SYSTEMS_ICC__) 99 # define MEM_STATIC static inline UNUSED_ATTR 100 #elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) 101 # define MEM_STATIC static inline 102 #elif defined(_MSC_VER) 103 # define MEM_STATIC static __inline 104 #else 105 # define MEM_STATIC static /* this version may generate warnings for unused static functions; disable the relevant warning */ 106 #endif 107 #endif 108 109 /* force no inlining */ 110 #ifdef _MSC_VER 111 # define FORCE_NOINLINE static __declspec(noinline) 112 #else 113 # if defined(__GNUC__) || defined(__IAR_SYSTEMS_ICC__) 114 # define FORCE_NOINLINE static __attribute__((__noinline__)) 115 # else 116 # define FORCE_NOINLINE static 117 # endif 118 #endif 119 120 121 /* target attribute */ 122 #if defined(__GNUC__) || defined(__IAR_SYSTEMS_ICC__) 123 # define TARGET_ATTRIBUTE(target) __attribute__((__target__(target))) 124 #else 125 # define TARGET_ATTRIBUTE(target) 126 #endif 127 128 /* Target attribute for BMI2 dynamic dispatch. 129 * Enable lzcnt, bmi, and bmi2. 130 * We test for bmi1 & bmi2. lzcnt is included in bmi1. 131 */ 132 #define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2") 133 134 /* prefetch 135 * can be disabled, by declaring NO_PREFETCH build macro */ 136 #if defined(NO_PREFETCH) 137 # define PREFETCH_L1(ptr) do { (void)(ptr); } while (0) /* disabled */ 138 # define PREFETCH_L2(ptr) do { (void)(ptr); } while (0) /* disabled */ 139 #else 140 # if defined(_MSC_VER) && (defined(_M_X64) || defined(_M_I86)) && !defined(_M_ARM64EC) /* _mm_prefetch() is not defined outside of x86/x64 */ 141 # include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */ 142 # define PREFETCH_L1(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T0) 143 # define PREFETCH_L2(ptr) _mm_prefetch((const char*)(ptr), _MM_HINT_T1) 144 # elif defined(__GNUC__) && ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) ) 145 # define PREFETCH_L1(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 3 /* locality */) 146 # define PREFETCH_L2(ptr) __builtin_prefetch((ptr), 0 /* rw==read */, 2 /* locality */) 147 # elif defined(__aarch64__) 148 # define PREFETCH_L1(ptr) do { __asm__ __volatile__("prfm pldl1keep, %0" ::"Q"(*(ptr))); } while (0) 149 # define PREFETCH_L2(ptr) do { __asm__ __volatile__("prfm pldl2keep, %0" ::"Q"(*(ptr))); } while (0) 150 # else 151 # define PREFETCH_L1(ptr) do { (void)(ptr); } while (0) /* disabled */ 152 # define PREFETCH_L2(ptr) do { (void)(ptr); } while (0) /* disabled */ 153 # endif 154 #endif /* NO_PREFETCH */ 155 156 #define CACHELINE_SIZE 64 157 158 #define PREFETCH_AREA(p, s) \ 159 do { \ 160 const char* const _ptr = (const char*)(p); \ 161 size_t const _size = (size_t)(s); \ 162 size_t _pos; \ 163 for (_pos=0; _pos<_size; _pos+=CACHELINE_SIZE) { \ 164 PREFETCH_L2(_ptr + _pos); \ 165 } \ 166 } while (0) 167 168 /* vectorization 169 * older GCC (pre gcc-4.3 picked as the cutoff) uses a different syntax, 170 * and some compilers, like Intel ICC and MCST LCC, do not support it at all. */ 171 #if !defined(__INTEL_COMPILER) && !defined(__clang__) && defined(__GNUC__) && !defined(__LCC__) 172 # if (__GNUC__ == 4 && __GNUC_MINOR__ > 3) || (__GNUC__ >= 5) 173 # define DONT_VECTORIZE __attribute__((optimize("no-tree-vectorize"))) 174 # else 175 # define DONT_VECTORIZE _Pragma("GCC optimize(\"no-tree-vectorize\")") 176 # endif 177 #else 178 # define DONT_VECTORIZE 179 #endif 180 181 /* Tell the compiler that a branch is likely or unlikely. 182 * Only use these macros if it causes the compiler to generate better code. 183 * If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc 184 * and clang, please do. 185 */ 186 #if defined(__GNUC__) 187 #define LIKELY(x) (__builtin_expect((x), 1)) 188 #define UNLIKELY(x) (__builtin_expect((x), 0)) 189 #else 190 #define LIKELY(x) (x) 191 #define UNLIKELY(x) (x) 192 #endif 193 194 #if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))) 195 # define ZSTD_UNREACHABLE do { assert(0), __builtin_unreachable(); } while (0) 196 #else 197 # define ZSTD_UNREACHABLE do { assert(0); } while (0) 198 #endif 199 200 /* disable warnings */ 201 #ifdef _MSC_VER /* Visual Studio */ 202 # include <intrin.h> /* For Visual 2005 */ 203 # pragma warning(disable : 4100) /* disable: C4100: unreferenced formal parameter */ 204 # pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */ 205 # pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */ 206 # pragma warning(disable : 4214) /* disable: C4214: non-int bitfields */ 207 # pragma warning(disable : 4324) /* disable: C4324: padded structure */ 208 #endif 209 210 /* compile time determination of SIMD support */ 211 #if !defined(ZSTD_NO_INTRINSICS) 212 # if defined(__AVX2__) 213 # define ZSTD_ARCH_X86_AVX2 214 # endif 215 # if defined(__SSE2__) || defined(_M_X64) || (defined (_M_IX86) && defined(_M_IX86_FP) && (_M_IX86_FP >= 2)) 216 # define ZSTD_ARCH_X86_SSE2 217 # endif 218 # if defined(__ARM_NEON) || defined(_M_ARM64) 219 # define ZSTD_ARCH_ARM_NEON 220 # endif 221 # 222 # if defined(ZSTD_ARCH_X86_AVX2) 223 # include <immintrin.h> 224 # endif 225 # if defined(ZSTD_ARCH_X86_SSE2) 226 # include <emmintrin.h> 227 # elif defined(ZSTD_ARCH_ARM_NEON) 228 # include <arm_neon.h> 229 # endif 230 #endif 231 232 /* C-language Attributes are added in C23. */ 233 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ > 201710L) && defined(__has_c_attribute) 234 # define ZSTD_HAS_C_ATTRIBUTE(x) __has_c_attribute(x) 235 #else 236 # define ZSTD_HAS_C_ATTRIBUTE(x) 0 237 #endif 238 239 /* Only use C++ attributes in C++. Some compilers report support for C++ 240 * attributes when compiling with C. 241 */ 242 #if defined(__cplusplus) && defined(__has_cpp_attribute) 243 # define ZSTD_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x) 244 #else 245 # define ZSTD_HAS_CPP_ATTRIBUTE(x) 0 246 #endif 247 248 /* Define ZSTD_FALLTHROUGH macro for annotating switch case with the 'fallthrough' attribute. 249 * - C23: https://en.cppreference.com/w/c/language/attributes/fallthrough 250 * - CPP17: https://en.cppreference.com/w/cpp/language/attributes/fallthrough 251 * - Else: __attribute__((__fallthrough__)) 252 */ 253 #ifndef ZSTD_FALLTHROUGH 254 # if ZSTD_HAS_C_ATTRIBUTE(fallthrough) 255 # define ZSTD_FALLTHROUGH [[fallthrough]] 256 # elif ZSTD_HAS_CPP_ATTRIBUTE(fallthrough) 257 # define ZSTD_FALLTHROUGH [[fallthrough]] 258 # elif __has_attribute(__fallthrough__) 259 /* Leading semicolon is to satisfy gcc-11 with -pedantic. Without the semicolon 260 * gcc complains about: a label can only be part of a statement and a declaration is not a statement. 261 */ 262 # define ZSTD_FALLTHROUGH ; __attribute__((__fallthrough__)) 263 # else 264 # define ZSTD_FALLTHROUGH 265 # endif 266 #endif 267 268 /*-************************************************************** 269 * Alignment 270 *****************************************************************/ 271 272 /* @return 1 if @u is a 2^n value, 0 otherwise 273 * useful to check a value is valid for alignment restrictions */ 274 MEM_STATIC int ZSTD_isPower2(size_t u) { 275 return (u & (u-1)) == 0; 276 } 277 278 /* this test was initially positioned in mem.h, 279 * but this file is removed (or replaced) for linux kernel 280 * so it's now hosted in compiler.h, 281 * which remains valid for both user & kernel spaces. 282 */ 283 284 #ifndef ZSTD_ALIGNOF 285 # if defined(__GNUC__) || defined(_MSC_VER) 286 /* covers gcc, clang & MSVC */ 287 /* note : this section must come first, before C11, 288 * due to a limitation in the kernel source generator */ 289 # define ZSTD_ALIGNOF(T) __alignof(T) 290 291 # elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) 292 /* C11 support */ 293 # include <stdalign.h> 294 # define ZSTD_ALIGNOF(T) alignof(T) 295 296 # else 297 /* No known support for alignof() - imperfect backup */ 298 # define ZSTD_ALIGNOF(T) (sizeof(void*) < sizeof(T) ? sizeof(void*) : sizeof(T)) 299 300 # endif 301 #endif /* ZSTD_ALIGNOF */ 302 303 #ifndef ZSTD_ALIGNED 304 /* C90-compatible alignment macro (GCC/Clang). Adjust for other compilers if needed. */ 305 # if defined(__GNUC__) || defined(__clang__) 306 # define ZSTD_ALIGNED(a) __attribute__((aligned(a))) 307 # elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 */ 308 # define ZSTD_ALIGNED(a) _Alignas(a) 309 #elif defined(_MSC_VER) 310 # define ZSTD_ALIGNED(n) __declspec(align(n)) 311 # else 312 /* this compiler will require its own alignment instruction */ 313 # define ZSTD_ALIGNED(...) 314 # endif 315 #endif /* ZSTD_ALIGNED */ 316 317 318 /*-************************************************************** 319 * Sanitizer 320 *****************************************************************/ 321 322 /** 323 * Zstd relies on pointer overflow in its decompressor. 324 * We add this attribute to functions that rely on pointer overflow. 325 */ 326 #ifndef ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 327 # if __has_attribute(no_sanitize) 328 # if !defined(__clang__) && defined(__GNUC__) && __GNUC__ < 8 329 /* gcc < 8 only has signed-integer-overlow which triggers on pointer overflow */ 330 # define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR __attribute__((no_sanitize("signed-integer-overflow"))) 331 # else 332 /* older versions of clang [3.7, 5.0) will warn that pointer-overflow is ignored. */ 333 # define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR __attribute__((no_sanitize("pointer-overflow"))) 334 # endif 335 # else 336 # define ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 337 # endif 338 #endif 339 340 /** 341 * Helper function to perform a wrapped pointer difference without triggering 342 * UBSAN. 343 * 344 * @returns lhs - rhs with wrapping 345 */ 346 MEM_STATIC 347 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 348 ptrdiff_t ZSTD_wrappedPtrDiff(unsigned char const* lhs, unsigned char const* rhs) 349 { 350 return lhs - rhs; 351 } 352 353 /** 354 * Helper function to perform a wrapped pointer add without triggering UBSAN. 355 * 356 * @return ptr + add with wrapping 357 */ 358 MEM_STATIC 359 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 360 unsigned char const* ZSTD_wrappedPtrAdd(unsigned char const* ptr, ptrdiff_t add) 361 { 362 return ptr + add; 363 } 364 365 /** 366 * Helper function to perform a wrapped pointer subtraction without triggering 367 * UBSAN. 368 * 369 * @return ptr - sub with wrapping 370 */ 371 MEM_STATIC 372 ZSTD_ALLOW_POINTER_OVERFLOW_ATTR 373 unsigned char const* ZSTD_wrappedPtrSub(unsigned char const* ptr, ptrdiff_t sub) 374 { 375 return ptr - sub; 376 } 377 378 /** 379 * Helper function to add to a pointer that works around C's undefined behavior 380 * of adding 0 to NULL. 381 * 382 * @returns `ptr + add` except it defines `NULL + 0 == NULL`. 383 */ 384 MEM_STATIC 385 unsigned char* ZSTD_maybeNullPtrAdd(unsigned char* ptr, ptrdiff_t add) 386 { 387 return add > 0 ? ptr + add : ptr; 388 } 389 390 /* Issue #3240 reports an ASAN failure on an llvm-mingw build. Out of an 391 * abundance of caution, disable our custom poisoning on mingw. */ 392 #ifdef __MINGW32__ 393 #ifndef ZSTD_ASAN_DONT_POISON_WORKSPACE 394 #define ZSTD_ASAN_DONT_POISON_WORKSPACE 1 395 #endif 396 #ifndef ZSTD_MSAN_DONT_POISON_WORKSPACE 397 #define ZSTD_MSAN_DONT_POISON_WORKSPACE 1 398 #endif 399 #endif 400 401 #if ZSTD_MEMORY_SANITIZER && !defined(ZSTD_MSAN_DONT_POISON_WORKSPACE) 402 /* Not all platforms that support msan provide sanitizers/msan_interface.h. 403 * We therefore declare the functions we need ourselves, rather than trying to 404 * include the header file... */ 405 #include <stddef.h> /* size_t */ 406 #define ZSTD_DEPS_NEED_STDINT 407 #include "zstd_deps.h" /* intptr_t */ 408 409 /* Make memory region fully initialized (without changing its contents). */ 410 void __msan_unpoison(const volatile void *a, size_t size); 411 412 /* Make memory region fully uninitialized (without changing its contents). 413 This is a legacy interface that does not update origin information. Use 414 __msan_allocated_memory() instead. */ 415 void __msan_poison(const volatile void *a, size_t size); 416 417 /* Returns the offset of the first (at least partially) poisoned byte in the 418 memory range, or -1 if the whole range is good. */ 419 intptr_t __msan_test_shadow(const volatile void *x, size_t size); 420 421 /* Print shadow and origin for the memory range to stderr in a human-readable 422 format. */ 423 void __msan_print_shadow(const volatile void *x, size_t size); 424 #endif 425 426 #if ZSTD_ADDRESS_SANITIZER && !defined(ZSTD_ASAN_DONT_POISON_WORKSPACE) 427 /* Not all platforms that support asan provide sanitizers/asan_interface.h. 428 * We therefore declare the functions we need ourselves, rather than trying to 429 * include the header file... */ 430 #include <stddef.h> /* size_t */ 431 432 /** 433 * Marks a memory region (<c>[addr, addr+size)</c>) as unaddressable. 434 * 435 * This memory must be previously allocated by your program. Instrumented 436 * code is forbidden from accessing addresses in this region until it is 437 * unpoisoned. This function is not guaranteed to poison the entire region - 438 * it could poison only a subregion of <c>[addr, addr+size)</c> due to ASan 439 * alignment restrictions. 440 * 441 * \note This function is not thread-safe because no two threads can poison or 442 * unpoison memory in the same memory region simultaneously. 443 * 444 * \param addr Start of memory region. 445 * \param size Size of memory region. */ 446 void __asan_poison_memory_region(void const volatile *addr, size_t size); 447 448 /** 449 * Marks a memory region (<c>[addr, addr+size)</c>) as addressable. 450 * 451 * This memory must be previously allocated by your program. Accessing 452 * addresses in this region is allowed until this region is poisoned again. 453 * This function could unpoison a super-region of <c>[addr, addr+size)</c> due 454 * to ASan alignment restrictions. 455 * 456 * \note This function is not thread-safe because no two threads can 457 * poison or unpoison memory in the same memory region simultaneously. 458 * 459 * \param addr Start of memory region. 460 * \param size Size of memory region. */ 461 void __asan_unpoison_memory_region(void const volatile *addr, size_t size); 462 #endif 463 464 #endif /* ZSTD_COMPILER_H */ 465
Indexes created Fri Jun 12 00:25:51 UTC 2026