uatomic/x86: Remove redundant memory barriers

[urcu.git] / include / urcu / compiler.h

diff --git a/include/urcu/compiler.h b/include/urcu/compiler.h
index 4806ee338a99706ae5bb9eedb503fdc54e00c661..197656c617d786f8af88f5648a60483ac224f3c4 100644 (file)
--- a/include/urcu/compiler.h
+++ b/include/urcu/compiler.h
@@ -1,30 +1,30 @@
+// SPDX-FileCopyrightText: 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+

 #ifndef _URCU_COMPILER_H
 #define _URCU_COMPILER_H
 
 /*
 #ifndef _URCU_COMPILER_H
 #define _URCU_COMPILER_H
 
 /*

- * compiler.h
- *

  * Compiler definitions.
  * Compiler definitions.

- *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.

  */
 
 #include <stddef.h>    /* for offsetof */
 
  */
 
 #include <stddef.h>    /* for offsetof */
 

+#if defined __cplusplus
+# include <type_traits>        /* for std::remove_cv */
+#endif
+
+#include <urcu/config.h>
+

 #define caa_likely(x)  __builtin_expect(!!(x), 1)
 #define caa_unlikely(x)        __builtin_expect(!!(x), 0)
 
 #define caa_likely(x)  __builtin_expect(!!(x), 1)
 #define caa_unlikely(x)        __builtin_expect(!!(x), 0)
 

-#define        cmm_barrier()   __asm__ __volatile__ ("" : : : "memory")
+#ifdef CONFIG_RCU_USE_ATOMIC_BUILTINS
+#  define cmm_barrier() __atomic_signal_fence(__ATOMIC_SEQ_CST)
+#else
+#  define cmm_barrier() __asm__ __volatile__ ("" : : : "memory")
+#endif

 
 /*
  * Instruct the compiler to perform only a single access to a variable
 
 /*
  * Instruct the compiler to perform only a single access to a variable


@@ -70,6 +70,23 @@
                (type *)((char *)__ptr - offsetof(type, member));       \
        })
 
                (type *)((char *)__ptr - offsetof(type, member));       \
        })
 

+/*
+ * caa_container_of_check_null - Get the address of an object containing a field.
+ *
+ * @ptr: pointer to the field.
+ * @type: type of the object.
+ * @member: name of the field within the object.
+ *
+ * Return the address of the object containing the field. Return NULL if
+ * @ptr is NULL.
+ */
+#define caa_container_of_check_null(ptr, type, member)                 \
+       __extension__                                                   \
+       ({                                                              \
+               const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \
+               (__ptr) ? (type *)((char *)__ptr - offsetof(type, member)) : NULL; \
+       })
+

 #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
 #define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))
 
 #define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
 #define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))
 


@@ -82,7 +99,7 @@
 #define __rcu
 
 #ifdef __cplusplus
 #define __rcu
 
 #ifdef __cplusplus

-#define URCU_FORCE_CAST(type, arg)     (reinterpret_cast<type>(arg))
+#define URCU_FORCE_CAST(_type, arg)    (reinterpret_cast<std::remove_cv<_type>::type>(arg))

 #else
 #define URCU_FORCE_CAST(type, arg)     ((type) (arg))
 #endif
 #else
 #define URCU_FORCE_CAST(type, arg)     ((type) (arg))
 #endif


@@ -108,10 +125,104 @@
 
 #define CAA_ARRAY_SIZE(x)      (sizeof(x) / sizeof((x)[0]))
 
 
 #define CAA_ARRAY_SIZE(x)      (sizeof(x) / sizeof((x)[0]))
 

-#ifdef __GNUC__
+/*
+ * URCU_GCC_VERSION is used to blacklist specific GCC versions with known
+ * bugs, clang also defines these macros to an equivalent GCC version it
+ * claims to support, so exclude it.
+ */
+#if defined(__GNUC__) && !defined(__clang__)

 # define URCU_GCC_VERSION      (__GNUC__ * 10000 \
                                + __GNUC_MINOR__ * 100 \
                                + __GNUC_PATCHLEVEL__)
 #endif
 
 # define URCU_GCC_VERSION      (__GNUC__ * 10000 \
                                + __GNUC_MINOR__ * 100 \
                                + __GNUC_PATCHLEVEL__)
 #endif
 

+#ifdef __cplusplus
+#define caa_unqual_scalar_typeof(x)                                    \
+       std::remove_cv<std::remove_reference<decltype(x)>::type>::type
+#else
+#define caa_scalar_type_to_expr(type)                                  \
+       unsigned type: (unsigned type)0,                                \
+       signed type: (signed type)0
+
+/*
+ * Use C11 _Generic to express unqualified type from expression. This removes
+ * volatile qualifier from expression type.
+ */
+#define caa_unqual_scalar_typeof(x)                                    \
+       __typeof__(                                                     \
+               _Generic((x),                                           \
+                       char: (char)0,                                  \
+                       caa_scalar_type_to_expr(char),                  \
+                       caa_scalar_type_to_expr(short),         \
+                       caa_scalar_type_to_expr(int),                   \
+                       caa_scalar_type_to_expr(long),                  \
+                       caa_scalar_type_to_expr(long long),             \
+                       default: (x)                                    \
+               )                                                       \
+       )
+#endif
+
+/*
+ * Allow user to manually define CMM_SANITIZE_THREAD if their toolchain is not
+ * supported by this check.
+ */
+#ifndef CMM_SANITIZE_THREAD
+# if defined(__GNUC__) && defined(__SANITIZE_THREAD__)
+#  define CMM_SANITIZE_THREAD
+# elif defined(__clang__) && defined(__has_feature)
+#  if __has_feature(thread_sanitizer)
+#   define CMM_SANITIZE_THREAD
+#  endif
+# endif
+#endif /* !CMM_SANITIZE_THREAD */
+
+/*
+ * Helper to add the volatile qualifier to a pointer.
+ */
+#if defined __cplusplus
+template <typename T>
+volatile T cmm_cast_volatile(T t)
+{
+    return static_cast<volatile T>(t);
+}
+#else
+#  define cmm_cast_volatile(ptr)                       \
+       __extension__                                   \
+       ({                                              \
+               (volatile __typeof__(ptr))(ptr);        \
+       })
+#endif
+
+/*
+ * Compile time assertion.
+ * - predicate: boolean expression to evaluate,
+ * - msg: string to print to the user on failure when `static_assert()` is
+ *   supported,
+ * - c_identifier_msg: message to be included in the typedef to emulate a
+ *   static assertion. This parameter must be a valid C identifier as it will
+ *   be used as a typedef name.
+ */
+#ifdef __cplusplus
+#define urcu_static_assert(predicate, msg, c_identifier_msg)  \
+       static_assert(predicate, msg)
+#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
+#define urcu_static_assert(predicate, msg, c_identifier_msg)  \
+       _Static_assert(predicate, msg)
+#else
+/*
+ * Evaluates the predicate and emit a compilation error on failure.
+ *
+ * If the predicate evaluates to true, this macro emits a function
+ * prototype with an argument type which is an array of size 0.
+ *
+ * If the predicate evaluates to false, this macro emits a function
+ * prototype with an argument type which is an array of negative size
+ * which is invalid in C and forces a compiler error. The
+ * c_identifier_msg parameter is used as the argument identifier so it
+ * is printed to the user when the error is reported.
+ */
+#define urcu_static_assert(predicate, msg, c_identifier_msg)  \
+       void urcu_static_assert_proto(char c_identifier_msg[2*!!(predicate)-1])
+#endif
+

 #endif /* _URCU_COMPILER_H */
 #endif /* _URCU_COMPILER_H */