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v261
src/basic/macro.h
207 строк
9 KB
Daan De Meyer
tree-wide: standardize header names across src/fundamental, src/basic and src/shared
21 май 2026, 04:33
21 май 2026, 04:33
74d392e
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #pragma once #include "../fundamental/macro.h" /* IWYU pragma: export */ #if !defined(HAS_FEATURE_MEMORY_SANITIZER) # if defined(__has_feature) # if __has_feature(memory_sanitizer) # define HAS_FEATURE_MEMORY_SANITIZER 1 # endif # endif # if !defined(HAS_FEATURE_MEMORY_SANITIZER) # define HAS_FEATURE_MEMORY_SANITIZER 0 # endif #endif #if !defined(HAS_FEATURE_ADDRESS_SANITIZER) # ifdef __SANITIZE_ADDRESS__ # define HAS_FEATURE_ADDRESS_SANITIZER 1 # elif defined(__has_feature) # if __has_feature(address_sanitizer) # define HAS_FEATURE_ADDRESS_SANITIZER 1 # endif # endif # if !defined(HAS_FEATURE_ADDRESS_SANITIZER) # define HAS_FEATURE_ADDRESS_SANITIZER 0 # endif #endif /* Note: on GCC "no_sanitize_address" is a function attribute only, on llvm it may also be applied to global * variables. We define a specific macro which knows this. Note that on GCC we don't need this decorator so much, since * our primary use case for this attribute is registration structures placed in named ELF sections which shall not be * padded, but GCC doesn't pad those anyway if AddressSanitizer is enabled. */ #if HAS_FEATURE_ADDRESS_SANITIZER && defined(__clang__) #define _variable_no_sanitize_address_ __attribute__((__no_sanitize_address__)) #else #define _variable_no_sanitize_address_ #endif /* Apparently there's no has_feature() call defined to check for ubsan, hence let's define this * unconditionally on llvm */ #if defined(__clang__) #define _function_no_sanitize_float_cast_overflow_ __attribute__((no_sanitize("float-cast-overflow"))) #else #define _function_no_sanitize_float_cast_overflow_ #endif /* test harness */ #define EXIT_TEST_SKIP 77 static inline uint64_t u64_multiply_safe(uint64_t a, uint64_t b) { if (_unlikely_(a != 0 && b > (UINT64_MAX / a))) return 0; /* overflow */ return a * b; } /* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */ static inline unsigned long ALIGN_POWER2(unsigned long u) { /* Avoid subtraction overflow */ if (u == 0) return 0; /* clz(0) is undefined */ if (u == 1) return 1; /* left-shift overflow is undefined */ if (__builtin_clzl(u - 1UL) < 1) return 0; return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL)); } /* * container_of - cast a member of a structure out to the containing structure * @ptr: the pointer to the member. * @type: the type of the container struct this is embedded in. * @member: the name of the member within the struct. */ #define container_of(ptr, type, member) __container_of(UNIQ, (ptr), type, member) #define __container_of(uniq, ptr, type, member) \ ({ \ const typeof( ((type*)0)->member ) *UNIQ_T(A, uniq) = (ptr); \ (type*)( (char *)UNIQ_T(A, uniq) - offsetof(type, member) ); \ }) #define PTR_TO_INT(p) ((int) ((intptr_t) (p))) #define INT_TO_PTR(u) ((void *) ((intptr_t) (u))) #define PTR_TO_UINT(p) ((unsigned) ((uintptr_t) (p))) #define UINT_TO_PTR(u) ((void *) ((uintptr_t) (u))) #define PTR_TO_LONG(p) ((long) ((intptr_t) (p))) #define LONG_TO_PTR(u) ((void *) ((intptr_t) (u))) #define PTR_TO_ULONG(p) ((unsigned long) ((uintptr_t) (p))) #define ULONG_TO_PTR(u) ((void *) ((uintptr_t) (u))) #define PTR_TO_UINT8(p) ((uint8_t) ((uintptr_t) (p))) #define UINT8_TO_PTR(u) ((void *) ((uintptr_t) (u))) #define PTR_TO_INT32(p) ((int32_t) ((intptr_t) (p))) #define INT32_TO_PTR(u) ((void *) ((intptr_t) (u))) #define PTR_TO_UINT32(p) ((uint32_t) ((uintptr_t) (p))) #define UINT32_TO_PTR(u) ((void *) ((uintptr_t) (u))) #define PTR_TO_INT64(p) ((int64_t) ((intptr_t) (p))) #define INT64_TO_PTR(u) ((void *) ((intptr_t) (u))) #define PTR_TO_UINT64(p) ((uint64_t) ((uintptr_t) (p))) #define UINT64_TO_PTR(u) ((void *) ((uintptr_t) (u))) #define CHAR_TO_STR(x) ((char[2]) { x, 0 }) #define char_array_0(x) x[sizeof(x)-1] = 0; /* Maximum buffer size needed for formatting an unsigned integer type as hex, including space for '0x' * prefix and trailing NUL suffix. */ #define HEXADECIMAL_STR_MAX(type) (2 + sizeof(type) * 2 + 1) /* Returns the number of chars needed to format variables of the specified type as a decimal string. Adds in * extra space for a negative '-' prefix for signed types. Includes space for the trailing NUL. */ #define DECIMAL_STR_MAX(type) \ ((size_t) IS_SIGNED_INTEGER_TYPE(type) + 1U + \ (sizeof(type) <= 1 ? 3U : \ sizeof(type) <= 2 ? 5U : \ sizeof(type) <= 4 ? 10U : \ sizeof(type) <= 8 ? (IS_SIGNED_INTEGER_TYPE(type) ? 19U : 20U) : sizeof(int[-2*(sizeof(type) > 8)]))) /* Returns the number of chars needed to format the specified integer value. It's hence more specific than * DECIMAL_STR_MAX() which answers the same question for all possible values of the specified type. Does * *not* include space for a trailing NUL. (If you wonder why we special case _x_ == 0 here: it's to trick * out gcc's -Wtype-limits, which would complain on comparing an unsigned type with < 0, otherwise. By * special-casing == 0 here first, we can use <= 0 instead of < 0 to trick out gcc.) */ #define DECIMAL_STR_WIDTH(x) \ ({ \ typeof(x) _x_ = (x); \ size_t ans; \ if (_x_ == 0) \ ans = 1; \ else { \ ans = _x_ <= 0 ? 2 : 1; \ while ((_x_ /= 10) != 0) \ ans++; \ } \ ans; \ }) #define SWAP_TWO(x, y) do { \ typeof(x) _t = (x); \ (x) = (y); \ (y) = (_t); \ } while (false) #define STRV_MAKE(...) ((char**) ((const char*[]) { __VA_ARGS__, NULL })) #define STRV_MAKE_CONST(...) ((const char* const*) ((const char*[]) { __VA_ARGS__, NULL })) /* Pointers range from NULL to POINTER_MAX */ #define POINTER_MAX ((void*) UINTPTR_MAX) /* A macro to force copying of a variable from memory. This is useful whenever we want to read something from * memory and want to make sure the compiler won't optimize away the destination variable for us. It's not * supposed to be a full CPU memory barrier, i.e. CPU is still allowed to reorder the reads, but it is not * allowed to remove our local copies of the variables. We want this to work for unaligned memory, hence * memcpy() is great for our purposes. */ #define READ_NOW(x) \ ({ \ typeof(x) _copy; \ memcpy(&_copy, &(x), sizeof(_copy)); \ asm volatile ("" : : : "memory"); \ _copy; \ }) #define saturate_add(x, y, limit) \ ({ \ typeof(limit) _x = (x); \ typeof(limit) _y = (y); \ _x > (limit) || _y >= (limit) - _x ? (limit) : _x + _y; \ }) static inline size_t size_add(size_t x, size_t y) { return saturate_add(x, y, SIZE_MAX); } /* A little helper for subtracting 1 off a pointer in a safe UB-free way. This is intended to be used for * loops that count down from a high pointer until some base. A naive loop would implement this like this: * * for (p = end-1; p >= base; p--) … * * But this is not safe because p before the base is UB in C. With this macro the loop becomes this instead: * * for (p = PTR_SUB1(end, base); p; p = PTR_SUB1(p, base)) … * * And is free from UB! */ #define PTR_SUB1(p, base) \ ({ \ typeof(p) _q = (p); \ _q && _q > (base) ? &_q[-1] : NULL; \ }) /* Iterate through each argument passed. All must be the same type as 'entry' or must be implicitly * convertible. The iteration variable 'entry' must already be defined. */ #define FOREACH_ARGUMENT(entry, ...) \ _FOREACH_ARGUMENT(entry, UNIQ_T(_entries_, UNIQ), UNIQ_T(_current_, UNIQ), UNIQ_T(_va_sentinel_, UNIQ), ##__VA_ARGS__) #define _FOREACH_ARGUMENT(entry, _entries_, _current_, _va_sentinel_, ...) \ for (typeof(entry) _va_sentinel_[1] = {}, _entries_[] = { __VA_ARGS__ __VA_OPT__(,) _va_sentinel_[0] }, *_current_ = _entries_; \ ((long)(_current_ - _entries_) < (long)(ELEMENTSOF(_entries_) - 1)) && ({ entry = *_current_; true; }); \ _current_++)