| 1 | #ifndef _URCU_COMPILER_H |
| 2 | #define _URCU_COMPILER_H |
| 3 | |
| 4 | /* |
| 5 | * compiler.h |
| 6 | * |
| 7 | * Compiler definitions. |
| 8 | * |
| 9 | * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 10 | * |
| 11 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 12 | * of this software and associated documentation files (the "Software"), to deal |
| 13 | * in the Software without restriction, including without limitation the rights |
| 14 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 15 | * copies of the Software, and to permit persons to whom the Software is |
| 16 | * furnished to do so, subject to the following conditions: |
| 17 | * |
| 18 | * The above copyright notice and this permission notice shall be included in |
| 19 | * all copies or substantial portions of the Software. |
| 20 | */ |
| 21 | |
| 22 | #include <stddef.h> /* for offsetof */ |
| 23 | |
| 24 | #define caa_likely(x) __builtin_expect(!!(x), 1) |
| 25 | #define caa_unlikely(x) __builtin_expect(!!(x), 0) |
| 26 | |
| 27 | #define cmm_barrier() asm volatile("" : : : "memory") |
| 28 | |
| 29 | /* |
| 30 | * Instruct the compiler to perform only a single access to a variable |
| 31 | * (prohibits merging and refetching). The compiler is also forbidden to reorder |
| 32 | * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of |
| 33 | * particular ordering. Compiler ordering can be ensured, for example, by |
| 34 | * putting two CMM_ACCESS_ONCE() in separate C statements. |
| 35 | * |
| 36 | * This macro does absolutely -nothing- to prevent the CPU from reordering, |
| 37 | * merging, or refetching absolutely anything at any time. Its main intended |
| 38 | * use is to mediate communication between process-level code and irq/NMI |
| 39 | * handlers, all running on the same CPU. |
| 40 | */ |
| 41 | #define CMM_ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) |
| 42 | |
| 43 | #ifndef caa_max |
| 44 | #define caa_max(a,b) ((a)>(b)?(a):(b)) |
| 45 | #endif |
| 46 | |
| 47 | #ifndef caa_min |
| 48 | #define caa_min(a,b) ((a)<(b)?(a):(b)) |
| 49 | #endif |
| 50 | |
| 51 | #if defined(__SIZEOF_LONG__) |
| 52 | #define CAA_BITS_PER_LONG (__SIZEOF_LONG__ * 8) |
| 53 | #elif defined(_LP64) |
| 54 | #define CAA_BITS_PER_LONG 64 |
| 55 | #else |
| 56 | #define CAA_BITS_PER_LONG 32 |
| 57 | #endif |
| 58 | |
| 59 | /* |
| 60 | * caa_container_of - Get the address of an object containing a field. |
| 61 | * |
| 62 | * @ptr: pointer to the field. |
| 63 | * @type: type of the object. |
| 64 | * @member: name of the field within the object. |
| 65 | */ |
| 66 | #define caa_container_of(ptr, type, member) \ |
| 67 | ({ \ |
| 68 | const typeof(((type *) NULL)->member) * __ptr = (ptr); \ |
| 69 | (type *)((char *)__ptr - offsetof(type, member)); \ |
| 70 | }) |
| 71 | |
| 72 | #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); })) |
| 73 | #define CAA_BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond)) |
| 74 | |
| 75 | /* |
| 76 | * __rcu is an annotation that documents RCU pointer accesses that need |
| 77 | * to be protected by a read-side critical section. Eventually, a static |
| 78 | * checker will be able to use this annotation to detect incorrect RCU |
| 79 | * usage. |
| 80 | */ |
| 81 | #define __rcu |
| 82 | |
| 83 | #ifdef __cplusplus |
| 84 | #define URCU_FORCE_CAST(type, arg) (reinterpret_cast<type>(arg)) |
| 85 | #else |
| 86 | #define URCU_FORCE_CAST(type, arg) ((type) (arg)) |
| 87 | #endif |
| 88 | |
| 89 | #define caa_is_signed_type(type) (((type) (-1)) < 0) |
| 90 | |
| 91 | #define caa_cast_long_keep_sign(v) \ |
| 92 | (caa_is_signed_type(__typeof__(v)) ? (long) (v) : (unsigned long) (v)) |
| 93 | |
| 94 | #endif /* _URCU_COMPILER_H */ |