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#ifndef RUBY_ATOMIC_H /*-*-C++-*-vi:se ft=cpp:*/
#define RUBY_ATOMIC_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Atomic operations
*
* Basically, if we could assume either C11 or C++11, these macros are just
* redundant. Sadly we cannot. We have to do them ourselves.
*/
#include "ruby/internal/config.h"
#ifdef STDC_HEADERS
# include <stddef.h> /* size_t */
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h> /* ssize_t */
#endif
#if RBIMPL_COMPILER_SINCE(MSVC, 13, 0, 0)
# pragma intrinsic(_InterlockedOr)
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
# include <atomic.h>
#endif
#include "ruby/assert.h"
#include "ruby/backward/2/limits.h"
#include "ruby/internal/attr/artificial.h"
#include "ruby/internal/attr/noalias.h"
#include "ruby/internal/attr/nonnull.h"
#include "ruby/internal/compiler_since.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/value.h"
#include "ruby/internal/static_assert.h"
#include "ruby/internal/stdbool.h"
/*
* Asserts that your environment supports more than one atomic types. These
* days systems tend to have such property (C11 was a standard of decades ago,
* right?) but we still support older ones.
*/
#if defined(__DOXYGEN__) || defined(HAVE_GCC_ATOMIC_BUILTINS) || defined(HAVE_GCC_SYNC_BUILTINS)
# define RUBY_ATOMIC_GENERIC_MACRO 1
#endif
/**
* Type that is eligible for atomic operations. Depending on your host
* platform you might have more than one such type, but we choose one of them
* anyways.
*/
#if defined(__DOXYGEN__)
using rb_atomic_t = std::atomic<unsigned>;
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
typedef unsigned int rb_atomic_t;
#elif defined(HAVE_GCC_SYNC_BUILTINS)
typedef unsigned int rb_atomic_t;
#elif defined(_WIN32)
typedef LONG rb_atomic_t;
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
typedef unsigned int rb_atomic_t;
#else
# error No atomic operation found
#endif
/**
* Atomically replaces the value pointed by `var` with the result of addition
* of `val` to the old value of `var`.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to add.
* @return What was stored in `var` before the addition.
* @post `var` holds `var + val`.
*/
#define RUBY_ATOMIC_FETCH_ADD(var, val) rbimpl_atomic_fetch_add(&(var), (val))
/**
* Atomically replaces the value pointed by `var` with the result of
* subtraction of `val` to the old value of `var`.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to subtract.
* @return What was stored in `var` before the subtraction.
* @post `var` holds `var - val`.
*/
#define RUBY_ATOMIC_FETCH_SUB(var, val) rbimpl_atomic_fetch_sub(&(var), (val))
/**
* Atomically replaces the value pointed by `var` with the result of
* bitwise OR between `val` and the old value of `var`.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to mix.
* @return void
* @post `var` holds `var | val`.
* @note For portability, this macro can return void.
*/
#define RUBY_ATOMIC_OR(var, val) rbimpl_atomic_or(&(var), (val))
/**
* Atomically replaces the value pointed by `var` with `val`. This is just an
* assignment, but you can additionally know the previous value.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to set.
* @return What was stored in `var` before the assignment.
* @post `var` holds `val`.
*/
#define RUBY_ATOMIC_EXCHANGE(var, val) rbimpl_atomic_exchange(&(var), (val))
/**
* Atomic compare-and-swap. This stores `val` to `var` if and only if the
* assignment changes the value of `var` from `oldval` to `newval`. You can
* detect whether the assignment happened or not using the return value.
*
* @param var A variable of ::rb_atomic_t.
* @param oldval Expected value of `var` before the assignment.
* @param newval What you want to store at `var`.
* @retval oldval Successful assignment (`var` is now `newval`).
* @retval otherwise Something else is at `var`; not updated.
*/
#define RUBY_ATOMIC_CAS(var, oldval, newval) \
rbimpl_atomic_cas(&(var), (oldval), (newval))
/**
* Identical to #RUBY_ATOMIC_EXCHANGE, except for the return type.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to set.
* @return void
* @post `var` holds `val`.
*/
#define RUBY_ATOMIC_SET(var, val) rbimpl_atomic_set(&(var), (val))
/**
* Identical to #RUBY_ATOMIC_FETCH_ADD, except for the return type.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to add.
* @return void
* @post `var` holds `var + val`.
*/
#define RUBY_ATOMIC_ADD(var, val) rbimpl_atomic_add(&(var), (val))
/**
* Identical to #RUBY_ATOMIC_FETCH_SUB, except for the return type.
*
* @param var A variable of ::rb_atomic_t.
* @param val Value to subtract.
* @return void
* @post `var` holds `var - val`.
*/
#define RUBY_ATOMIC_SUB(var, val) rbimpl_atomic_sub(&(var), (val))
/**
* Atomically increments the value pointed by `var`.
*
* @param var A variable of ::rb_atomic_t.
* @return void
* @post `var` holds `var + 1`.
*/
#define RUBY_ATOMIC_INC(var) rbimpl_atomic_inc(&(var))
/**
* Atomically decrements the value pointed by `var`.
*
* @param var A variable of ::rb_atomic_t.
* @return void
* @post `var` holds `var - 1`.
*/
#define RUBY_ATOMIC_DEC(var) rbimpl_atomic_dec(&(var))
/**
* Identical to #RUBY_ATOMIC_INC, except it expects its argument is `size_t`.
* There are cases where ::rb_atomic_t is 32bit while `size_t` is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `size_t`.
* @return void
* @post `var` holds `var + 1`.
*/
#define RUBY_ATOMIC_SIZE_INC(var) rbimpl_atomic_size_inc(&(var))
/**
* Identical to #RUBY_ATOMIC_DEC, except it expects its argument is `size_t`.
* There are cases where ::rb_atomic_t is 32bit while `size_t` is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `size_t`.
* @return void
* @post `var` holds `var - 1`.
*/
#define RUBY_ATOMIC_SIZE_DEC(var) rbimpl_atomic_size_dec(&(var))
/**
* Identical to #RUBY_ATOMIC_EXCHANGE, except it expects its arguments are
* `size_t`. There are cases where ::rb_atomic_t is 32bit while `size_t` is
* 64bit. This should be used for size related operations to support such
* platforms.
*
* @param var A variable of `size_t`.
* @param val Value to set.
* @return What was stored in `var` before the assignment.
* @post `var` holds `val`.
*/
#define RUBY_ATOMIC_SIZE_EXCHANGE(var, val) \
rbimpl_atomic_size_exchange(&(var), (val))
/**
* Identical to #RUBY_ATOMIC_CAS, except it expects its arguments are `size_t`.
* There are cases where ::rb_atomic_t is 32bit while `size_t` is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `size_t`.
* @param oldval Expected value of `var` before the assignment.
* @param newval What you want to store at `var`.
* @retval oldval Successful assignment (`var` is now `newval`).
* @retval otherwise Something else is at `var`; not updated.
*/
#define RUBY_ATOMIC_SIZE_CAS(var, oldval, newval) \
rbimpl_atomic_size_cas(&(var), (oldval), (newval))
/**
* Identical to #RUBY_ATOMIC_ADD, except it expects its arguments are `size_t`.
* There are cases where ::rb_atomic_t is 32bit while `size_t` is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `size_t`.
* @param val Value to add.
* @return void
* @post `var` holds `var + val`.
*/
#define RUBY_ATOMIC_SIZE_ADD(var, val) rbimpl_atomic_size_add(&(var), (val))
/**
* Identical to #RUBY_ATOMIC_SUB, except it expects its arguments are `size_t`.
* There are cases where ::rb_atomic_t is 32bit while `size_t` is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `size_t`.
* @param val Value to subtract.
* @return void
* @post `var` holds `var - val`.
*/
#define RUBY_ATOMIC_SIZE_SUB(var, val) rbimpl_atomic_size_sub(&(var), (val))
/**
* Identical to #RUBY_ATOMIC_EXCHANGE, except it expects its arguments are
* `void*`. There are cases where ::rb_atomic_t is 32bit while `void*` is
* 64bit. This should be used for pointer related operations to support such
* platforms.
*
* @param var A variable of `void *`.
* @param val Value to set.
* @return What was stored in `var` before the assignment.
* @post `var` holds `val`.
*
* @internal
*
* :FIXME: this `(void*)` cast is evil! However `void*` is incompatible with
* some pointers, most notably function pointers.
*/
#define RUBY_ATOMIC_PTR_EXCHANGE(var, val) \
RBIMPL_CAST(rbimpl_atomic_ptr_exchange((void **)&(var), (void *)val))
/**
* Identical to #RUBY_ATOMIC_CAS, except it expects its arguments are `void*`.
* There are cases where ::rb_atomic_t is 32bit while `void*` is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `void*`.
* @param oldval Expected value of `var` before the assignment.
* @param newval What you want to store at `var`.
* @retval oldval Successful assignment (`var` is now `newval`).
* @retval otherwise Something else is at `var`; not updated.
*/
#define RUBY_ATOMIC_PTR_CAS(var, oldval, newval) \
RBIMPL_CAST(rbimpl_atomic_ptr_cas((void **)&(var), (oldval), (newval)))
/**
* Identical to #RUBY_ATOMIC_EXCHANGE, except it expects its arguments are
* ::VALUE. There are cases where ::rb_atomic_t is 32bit while ::VALUE is
* 64bit. This should be used for pointer related operations to support such
* platforms.
*
* @param var A variable of ::VALUE.
* @param val Value to set.
* @return What was stored in `var` before the assignment.
* @post `var` holds `val`.
*/
#define RUBY_ATOMIC_VALUE_EXCHANGE(var, val) \
rbimpl_atomic_value_exchange(&(var), (val))
/**
* Identical to #RUBY_ATOMIC_CAS, except it expects its arguments are ::VALUE.
* There are cases where ::rb_atomic_t is 32bit while ::VALUE is 64bit. This
* should be used for size related operations to support such platforms.
*
* @param var A variable of `void*`.
* @param oldval Expected value of `var` before the assignment.
* @param newval What you want to store at `var`.
* @retval oldval Successful assignment (`var` is now `newval`).
* @retval otherwise Something else is at `var`; not updated.
*/
#define RUBY_ATOMIC_VALUE_CAS(var, oldval, newval) \
rbimpl_atomic_value_cas(&(var), (oldval), (newval))
/** @cond INTERNAL_MACRO */
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline rb_atomic_t
rbimpl_atomic_fetch_add(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
return __atomic_fetch_add(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
return __sync_fetch_and_add(ptr, val);
#elif defined(_WIN32)
return InterlockedExchangeAdd(ptr, val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
/*
* `atomic_add_int_nv` takes its second argument as `int`! Meanwhile our
* `rb_atomic_t` is unsigned. We cannot pass `val` as-is. We have to
* manually check integer overflow.
*/
RBIMPL_ASSERT_OR_ASSUME(val <= INT_MAX);
return atomic_add_int_nv(ptr, val) - val;
#else
# error Unsupported platform.
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_add(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
/*
* GCC on amd64 is smart enough to detect this `__atomic_add_fetch`'s
* return value is not used, then compiles it into single `LOCK ADD`
* instruction.
*/
__atomic_add_fetch(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
__sync_add_and_fetch(ptr, val);
#elif defined(_WIN32)
/*
* `InterlockedExchangeAdd` is `LOCK XADD`. It seems there also is
* `_InterlockedAdd` intrinsic in ARM Windows but not for x86? Sticking to
* `InterlockedExchangeAdd` for better portability.
*/
InterlockedExchangeAdd(ptr, val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
/* Ditto for `atomic_add_int_nv`. */
RBIMPL_ASSERT_OR_ASSUME(val <= INT_MAX);
atomic_add_int(ptr, val);
#else
# error Unsupported platform.
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_size_add(volatile size_t *ptr, size_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_add_fetch(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
__sync_add_and_fetch(ptr, val);
#elif defined(_WIN32) && defined(_M_AMD64)
/* Ditto for `InterlockeExchangedAdd`. */
InterlockedExchangeAdd64(ptr, val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
/* Ditto for `atomic_add_int_nv`. */
RBIMPL_ASSERT_OR_ASSUME(val <= LONG_MAX);
atomic_add_long(ptr, val);
#else
RBIMPL_STATIC_ASSERT(size_of_rb_atomic_t, sizeof *ptr == sizeof(rb_atomic_t));
volatile rb_atomic_t *const tmp = RBIMPL_CAST((volatile rb_atomic_t *)ptr);
rbimpl_atomic_add(tmp, val);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_inc(volatile rb_atomic_t *ptr)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS) || defined(HAVE_GCC_SYNC_BUILTINS)
rbimpl_atomic_add(ptr, 1);
#elif defined(_WIN32)
InterlockedIncrement(ptr);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
atomic_inc_uint(ptr);
#else
rbimpl_atomic_add(ptr, 1);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_size_inc(volatile size_t *ptr)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS) || defined(HAVE_GCC_SYNC_BUILTINS)
rbimpl_atomic_size_add(ptr, 1);
#elif defined(_WIN32) && defined(_M_AMD64)
InterlockedIncrement64(ptr);
#elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
atomic_inc_ulong(ptr);
#else
rbimpl_atomic_size_add(ptr, 1);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline rb_atomic_t
rbimpl_atomic_fetch_sub(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
return __atomic_fetch_sub(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
return __sync_fetch_and_sub(ptr, val);
#elif defined(_WIN32)
/* rb_atomic_t is signed here! Safe to do `-val`. */
return InterlockedExchangeAdd(ptr, -val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
/* Ditto for `rbimpl_atomic_fetch_add`. */
const signed neg = -1;
RBIMPL_ASSERT_OR_ASSUME(val <= INT_MAX);
return atomic_add_int_nv(ptr, neg * val) + val;
#else
# error Unsupported platform.
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_sub(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_sub_fetch(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
__sync_sub_and_fetch(ptr, val);
#elif defined(_WIN32)
InterlockedExchangeAdd(ptr, -val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
const signed neg = -1;
RBIMPL_ASSERT_OR_ASSUME(val <= INT_MAX);
atomic_add_int(ptr, neg * val);
#else
# error Unsupported platform.
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_size_sub(volatile size_t *ptr, size_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_sub_fetch(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
__sync_sub_and_fetch(ptr, val);
#elif defined(_WIN32) && defined(_M_AMD64)
const ssize_t neg = -1;
InterlockedExchangeAdd64(ptr, neg * val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
const signed neg = -1;
RBIMPL_ASSERT_OR_ASSUME(val <= LONG_MAX);
atomic_add_long(ptr, neg * val);
#else
RBIMPL_STATIC_ASSERT(size_of_rb_atomic_t, sizeof *ptr == sizeof(rb_atomic_t));
volatile rb_atomic_t *const tmp = RBIMPL_CAST((volatile rb_atomic_t *)ptr);
rbimpl_atomic_sub(tmp, val);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_dec(volatile rb_atomic_t *ptr)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS) || defined(HAVE_GCC_SYNC_BUILTINS)
rbimpl_atomic_sub(ptr, 1);
#elif defined(_WIN32)
InterlockedDecrement(ptr);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
atomic_dec_uint(ptr);
#else
rbimpl_atomic_sub(ptr, 1);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_size_dec(volatile size_t *ptr)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS) || defined(HAVE_GCC_SYNC_BUILTINS)
rbimpl_atomic_size_sub(ptr, 1);
#elif defined(_WIN32) && defined(_M_AMD64)
InterlockedDecrement64(ptr);
#elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
atomic_dec_ulong(ptr);
#else
rbimpl_atomic_size_sub(ptr, 1);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_or(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_or_fetch(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
__sync_or_and_fetch(ptr, val);
#elif RBIMPL_COMPILER_SINCE(MSVC, 13, 0, 0)
_InterlockedOr(ptr, val);
#elif defined(_WIN32) && defined(__GNUC__)
/* This was for old MinGW. Maybe not needed any longer? */
__asm__(
"lock\n\t"
"orl\t%1, %0"
: "=m"(ptr)
: "Ir"(val));
#elif defined(_WIN32) && defined(_M_IX86)
__asm mov eax, ptr;
__asm mov ecx, val;
__asm lock or [eax], ecx;
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
atomic_or_uint(ptr, val);
#else
# error Unsupported platform.
#endif
}
/* Nobody uses this but for theoretical backwards compatibility... */
#if RBIMPL_COMPILER_BEFORE(MSVC, 13, 0, 0)
static inline rb_atomic_t
rb_w32_atomic_or(volatile rb_atomic_t *var, rb_atomic_t val)
{
return rbimpl_atomic_or(var, val);
}
#endif
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline rb_atomic_t
rbimpl_atomic_exchange(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
return __atomic_exchange_n(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
return __sync_lock_test_and_set(ptr, val);
#elif defined(_WIN32)
return InterlockedExchange(ptr, val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
return atomic_swap_uint(ptr, val);
#else
# error Unsupported platform.
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline size_t
rbimpl_atomic_size_exchange(volatile size_t *ptr, size_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
return __atomic_exchange_n(ptr, val, __ATOMIC_SEQ_CST);
#elif defined(HAVE_GCC_SYNC_BUILTINS)
return __sync_lock_test_and_set(ptr, val);
#elif defined(_WIN32) && defined(_M_AMD64)
return InterlockedExchange64(ptr, val);
#elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
return atomic_swap_ulong(ptr, val);
#else
RBIMPL_STATIC_ASSERT(size_of_size_t, sizeof *ptr == sizeof(rb_atomic_t));
volatile rb_atomic_t *const tmp = RBIMPL_CAST((volatile rb_atomic_t *)ptr);
const rb_atomic_t ret = rbimpl_atomic_exchange(tmp, val);
return RBIMPL_CAST((size_t)ret);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void *
rbimpl_atomic_ptr_exchange(void *volatile *ptr, const void *val)
{
#if 0
#elif defined(InterlockedExchangePointer)
/* const_cast */
PVOID *pptr = RBIMPL_CAST((PVOID *)ptr);
PVOID pval = RBIMPL_CAST((PVOID)val);
return InterlockedExchangePointer(pptr, pval);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
return atomic_swap_ptr(ptr, RBIMPL_CAST((void *)val));
#else
RBIMPL_STATIC_ASSERT(sizeof_voidp, sizeof *ptr == sizeof(size_t));
const size_t sval = RBIMPL_CAST((size_t)val);
volatile size_t *const sptr = RBIMPL_CAST((volatile size_t *)ptr);
const size_t sret = rbimpl_atomic_size_exchange(sptr, sval);
return RBIMPL_CAST((void *)sret);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline VALUE
rbimpl_atomic_value_exchange(volatile VALUE *ptr, VALUE val)
{
RBIMPL_STATIC_ASSERT(sizeof_value, sizeof *ptr == sizeof(size_t));
const size_t sval = RBIMPL_CAST((size_t)val);
volatile size_t *const sptr = RBIMPL_CAST((volatile size_t *)ptr);
const size_t sret = rbimpl_atomic_size_exchange(sptr, sval);
return RBIMPL_CAST((VALUE)sret);
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void
rbimpl_atomic_set(volatile rb_atomic_t *ptr, rb_atomic_t val)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_store_n(ptr, val, __ATOMIC_SEQ_CST);
#else
/* Maybe std::atomic<rb_atomic_t>::store can be faster? */
rbimpl_atomic_exchange(ptr, val);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline rb_atomic_t
rbimpl_atomic_cas(volatile rb_atomic_t *ptr, rb_atomic_t oldval, rb_atomic_t newval)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_compare_exchange_n(
ptr, &oldval, newval, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
return oldval;
#elif defined(HAVE_GCC_SYNC_BUILTINS)
return __sync_val_compare_and_swap(ptr, oldval, newval);
#elif RBIMPL_COMPILER_SINCE(MSVC, 13, 0, 0)
return InterlockedCompareExchange(ptr, newval, oldval);
#elif defined(_WIN32)
PVOID *pptr = RBIMPL_CAST((PVOID *)ptr);
PVOID pold = RBIMPL_CAST((PVOID)oldval);
PVOID pnew = RBIMPL_CAST((PVOID)newval);
PVOID pret = InterlockedCompareExchange(pptr, pnew, pold);
return RBIMPL_CAST((rb_atomic_t)pret);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
return atomic_cas_uint(ptr, oldval, newval);
#else
# error Unsupported platform.
#endif
}
/* Nobody uses this but for theoretical backwards compatibility... */
#if RBIMPL_COMPILER_BEFORE(MSVC, 13, 0, 0)
static inline rb_atomic_t
rb_w32_atomic_cas(volatile rb_atomic_t *var, rb_atomic_t oldval, rb_atomic_t newval)
{
return rbimpl_atomic_cas(var, oldval, newval);
}
#endif
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline size_t
rbimpl_atomic_size_cas(volatile size_t *ptr, size_t oldval, size_t newval)
{
#if 0
#elif defined(HAVE_GCC_ATOMIC_BUILTINS)
__atomic_compare_exchange_n(
ptr, &oldval, newval, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
return oldval;
#elif defined(HAVE_GCC_SYNC_BUILTINS)
return __sync_val_compare_and_swap(ptr, oldval, newval);
#elif defined(_WIN32) && defined(_M_AMD64)
return InterlockedCompareExchange64(ptr, newval, oldval);
#elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
return atomic_cas_ulong(ptr, oldval, newval);
#else
RBIMPL_STATIC_ASSERT(size_of_size_t, sizeof *ptr == sizeof(rb_atomic_t));
volatile rb_atomic_t *tmp = RBIMPL_CAST((volatile rb_atomic_t *)ptr);
return rbimpl_atomic_cas(tmp, oldval, newval);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline void *
rbimpl_atomic_ptr_cas(void **ptr, const void *oldval, const void *newval)
{
#if 0
#elif defined(InterlockedExchangePointer)
/* ... Can we say that InterlockedCompareExchangePtr surly exists when
* InterlockedExchangePointer is defined? Seems so but...?*/
PVOID *pptr = RBIMPL_CAST((PVOID *)ptr);
PVOID pold = RBIMPL_CAST((PVOID)oldval);
PVOID pnew = RBIMPL_CAST((PVOID)newval);
return InterlockedCompareExchangePointer(pptr, pnew, pold);
#elif defined(__sun) && defined(HAVE_ATOMIC_H)
void *pold = RBIMPL_CAST((void *)oldval);
void *pnew = RBIMPL_CAST((void *)newval);
return atomic_cas_ptr(ptr, pold, pnew);
#else
RBIMPL_STATIC_ASSERT(sizeof_voidp, sizeof *ptr == sizeof(size_t));
const size_t snew = RBIMPL_CAST((size_t)newval);
const size_t sold = RBIMPL_CAST((size_t)oldval);
volatile size_t *const sptr = RBIMPL_CAST((volatile size_t *)ptr);
const size_t sret = rbimpl_atomic_size_cas(sptr, sold, snew);
return RBIMPL_CAST((void *)sret);
#endif
}
RBIMPL_ATTR_ARTIFICIAL()
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL((1))
static inline VALUE
rbimpl_atomic_value_cas(volatile VALUE *ptr, VALUE oldval, VALUE newval)
{
RBIMPL_STATIC_ASSERT(sizeof_value, sizeof *ptr == sizeof(size_t));
const size_t snew = RBIMPL_CAST((size_t)newval);
const size_t sold = RBIMPL_CAST((size_t)oldval);
volatile size_t *const sptr = RBIMPL_CAST((volatile size_t *)ptr);
const size_t sret = rbimpl_atomic_size_cas(sptr, sold, snew);
return RBIMPL_CAST((VALUE)sret);
}
/** @endcond */
#endif /* RUBY_ATOMIC_H */
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