| 1 | // SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 2 | // |
| 3 | // SPDX-License-Identifier: LGPL-2.1-or-later |
| 4 | |
| 5 | #ifndef _URCU_COMPILER_H |
| 6 | #define _URCU_COMPILER_H |
| 7 | |
| 8 | /* |
| 9 | * Compiler definitions. |
| 10 | */ |
| 11 | |
| 12 | #include <stddef.h> /* for offsetof */ |
| 13 | |
| 14 | #if defined __cplusplus |
| 15 | # include <type_traits> /* for std::remove_cv */ |
| 16 | #endif |
| 17 | |
| 18 | #define caa_likely(x) __builtin_expect(!!(x), 1) |
| 19 | #define caa_unlikely(x) __builtin_expect(!!(x), 0) |
| 20 | |
| 21 | #define cmm_barrier() __asm__ __volatile__ ("" : : : "memory") |
| 22 | |
| 23 | /* |
| 24 | * Instruct the compiler to perform only a single access to a variable |
| 25 | * (prohibits merging and refetching). The compiler is also forbidden to reorder |
| 26 | * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of |
| 27 | * particular ordering. Compiler ordering can be ensured, for example, by |
| 28 | * putting two CMM_ACCESS_ONCE() in separate C statements. |
| 29 | * |
| 30 | * This macro does absolutely -nothing- to prevent the CPU from reordering, |
| 31 | * merging, or refetching absolutely anything at any time. Its main intended |
| 32 | * use is to mediate communication between process-level code and irq/NMI |
| 33 | * handlers, all running on the same CPU. |
| 34 | */ |
| 35 | #define CMM_ACCESS_ONCE(x) (*(__volatile__ __typeof__(x) *)&(x)) |
| 36 | |
| 37 | #ifndef caa_max |
| 38 | #define caa_max(a,b) ((a)>(b)?(a):(b)) |
| 39 | #endif |
| 40 | |
| 41 | #ifndef caa_min |
| 42 | #define caa_min(a,b) ((a)<(b)?(a):(b)) |
| 43 | #endif |
| 44 | |
| 45 | #if defined(__SIZEOF_LONG__) |
| 46 | #define CAA_BITS_PER_LONG (__SIZEOF_LONG__ * 8) |
| 47 | #elif defined(_LP64) |
| 48 | #define CAA_BITS_PER_LONG 64 |
| 49 | #else |
| 50 | #define CAA_BITS_PER_LONG 32 |
| 51 | #endif |
| 52 | |
| 53 | /* |
| 54 | * caa_container_of - Get the address of an object containing a field. |
| 55 | * |
| 56 | * @ptr: pointer to the field. |
| 57 | * @type: type of the object. |
| 58 | * @member: name of the field within the object. |
| 59 | */ |
| 60 | #define caa_container_of(ptr, type, member) \ |
| 61 | __extension__ \ |
| 62 | ({ \ |
| 63 | const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \ |
| 64 | (type *)((char *)__ptr - offsetof(type, member)); \ |
| 65 | }) |
| 66 | |
| 67 | /* |
| 68 | * caa_container_of_check_null - Get the address of an object containing a field. |
| 69 | * |
| 70 | * @ptr: pointer to the field. |
| 71 | * @type: type of the object. |
| 72 | * @member: name of the field within the object. |
| 73 | * |
| 74 | * Return the address of the object containing the field. Return NULL if |
| 75 | * @ptr is NULL. |
| 76 | */ |
| 77 | #define caa_container_of_check_null(ptr, type, member) \ |
| 78 | __extension__ \ |
| 79 | ({ \ |
| 80 | const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \ |
| 81 | (__ptr) ? (type *)((char *)__ptr - offsetof(type, member)) : NULL; \ |
| 82 | }) |
| 83 | |
| 84 | #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); })) |
| 85 | #define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond)) |
| 86 | |
| 87 | /* |
| 88 | * __rcu is an annotation that documents RCU pointer accesses that need |
| 89 | * to be protected by a read-side critical section. Eventually, a static |
| 90 | * checker will be able to use this annotation to detect incorrect RCU |
| 91 | * usage. |
| 92 | */ |
| 93 | #define __rcu |
| 94 | |
| 95 | #ifdef __cplusplus |
| 96 | #define URCU_FORCE_CAST(_type, arg) (reinterpret_cast<std::remove_cv<_type>::type>(arg)) |
| 97 | #else |
| 98 | #define URCU_FORCE_CAST(type, arg) ((type) (arg)) |
| 99 | #endif |
| 100 | |
| 101 | #define caa_is_signed_type(type) ((type) -1 < (type) 0) |
| 102 | |
| 103 | /* |
| 104 | * Cast to unsigned long, sign-extending if @v is signed. |
| 105 | * Note: casting to a larger type or to same type size keeps the sign of |
| 106 | * the expression being cast (see C99 6.3.1.3). |
| 107 | */ |
| 108 | #define caa_cast_long_keep_sign(v) ((unsigned long) (v)) |
| 109 | |
| 110 | #if defined (__GNUC__) \ |
| 111 | && ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5) \ |
| 112 | || __GNUC__ >= 5) |
| 113 | #define CDS_DEPRECATED(msg) \ |
| 114 | __attribute__((deprecated(msg))) |
| 115 | #else |
| 116 | #define CDS_DEPRECATED(msg) \ |
| 117 | __attribute__((deprecated)) |
| 118 | #endif |
| 119 | |
| 120 | #define CAA_ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) |
| 121 | |
| 122 | /* |
| 123 | * URCU_GCC_VERSION is used to blacklist specific GCC versions with known |
| 124 | * bugs, clang also defines these macros to an equivalent GCC version it |
| 125 | * claims to support, so exclude it. |
| 126 | */ |
| 127 | #if defined(__GNUC__) && !defined(__clang__) |
| 128 | # define URCU_GCC_VERSION (__GNUC__ * 10000 \ |
| 129 | + __GNUC_MINOR__ * 100 \ |
| 130 | + __GNUC_PATCHLEVEL__) |
| 131 | #endif |
| 132 | |
| 133 | #endif /* _URCU_COMPILER_H */ |