ruby_atomic.h: atomic VALUE operations

* ruby_atomic.h (ATOMIC_VALUE_EXCHANGE, ATOMIC_VALUE_CAS): add
  atomic operations for VALUE.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51498 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Thu Aug  6 10:44:00 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ruby_atomic.h (ATOMIC_VALUE_EXCHANGE, ATOMIC_VALUE_CAS): add
+	  atomic operations for VALUE.
+
 Thu Aug  6 08:15:49 2015  Aaron Patterson <tenderlove@ruby-lang.org>
 
 	* ext/openssl/lib/openssl/ssl.rb (module OpenSSL): move

eval.c

@@ -200,7 +200,7 @@ ruby_cleanup(volatile int ex)
 
     state = 0;
     for (nerr = 0; nerr < numberof(errs); ++nerr) {
-	VALUE err = ATOMIC_SIZE_EXCHANGE(errs[nerr], Qnil);
+	VALUE err = ATOMIC_VALUE_EXCHANGE(errs[nerr], Qnil);
 
 	if (!RTEST(err)) continue;
 

gc.c

@@ -2633,7 +2633,7 @@ finalize_deferred(rb_objspace_t *objspace)
 {
     VALUE zombie;
 
-    while ((zombie = (VALUE)ATOMIC_PTR_EXCHANGE(heap_pages_deferred_final, 0)) != 0) {
+    while ((zombie = ATOMIC_VALUE_EXCHANGE(heap_pages_deferred_final, 0)) != 0) {
 	finalize_list(objspace, zombie);
     }
 }

node.c

@@ -1090,11 +1090,9 @@ rb_alloc_tmp_buffer(volatile VALUE *store, long len)
 void
 rb_free_tmp_buffer(volatile VALUE *store)
 {
-    VALUE s = *store;
-    *store = 0;
+    VALUE s = ATOMIC_VALUE_EXCHANGE(*store, 0);
     if (s) {
-	void *ptr = RNODE(s)->u1.node;
-	RNODE(s)->u1.node = 0;
+	void *ptr = ATOMIC_PTR_EXCHANGE(RNODE(s)->u1.node, 0);
 	RNODE(s)->u3.cnt = 0;
 	xfree(ptr);
     }

ruby_atomic.h

@@ -17,8 +17,7 @@ typedef unsigned int rb_atomic_t;
 # define ATOMIC_SIZE_ADD(var, val) __atomic_fetch_add(&(var), (val), __ATOMIC_SEQ_CST)
 # define ATOMIC_SIZE_SUB(var, val) __atomic_fetch_sub(&(var), (val), __ATOMIC_SEQ_CST)
 
-# define ATOMIC_PTR_EXCHANGE(var, val) __atomic_exchange_n(&(var), (val), __ATOMIC_SEQ_CST)
-# define ATOMIC_PTR_CAS(var, oldval, newval) ATOMIC_CAS(var, oldval, newval)
+# define RUBY_ATOMIC_GENERIC_MACRO 1
 
 #elif defined HAVE_GCC_SYNC_BUILTINS
 /* @shyouhei hack to support atomic operations in case of gcc. Gcc
@@ -36,8 +35,7 @@ typedef unsigned int rb_atomic_t; /* Anything OK */
 # define ATOMIC_SIZE_ADD(var, val) __sync_fetch_and_add(&(var), (val))
 # define ATOMIC_SIZE_SUB(var, val) __sync_fetch_and_sub(&(var), (val))
 
-# define ATOMIC_PTR_EXCHANGE(var, val) __sync_lock_test_and_set(&(var), (val))
-# define ATOMIC_PTR_CAS(var, oldval, newval) ATOMIC_CAS(var, oldval, newval)
+# define RUBY_ATOMIC_GENERIC_MACRO 1
 
 #elif defined _WIN32
 #if defined _MSC_VER && _MSC_VER > 1200
@@ -135,9 +133,9 @@ extern rb_atomic_t ruby_atomic_compare_and_swap(rb_atomic_t *ptr,
 
 # define ATOMIC_SIZE_ADD(var, val) (void)((var) += (val))
 # define ATOMIC_SIZE_SUB(var, val) (void)((var) -= (val))
-# define ATOMIC_SIZE_EXCHANGE(var, val) atomic_size_exchange(&(var), (val))
+# define ATOMIC_SIZE_EXCHANGE(var, val) ruby_atomic_size_exchange(&(var), (val))
 static inline size_t
-atomic_size_exchange(size_t *ptr, size_t val)
+ruby_atomic_size_exchange(size_t *ptr, size_t val)
 {
     size_t old = *ptr;
     *ptr = val;
@@ -158,14 +156,77 @@ atomic_size_exchange(size_t *ptr, size_t val)
 # define ATOMIC_SIZE_CAS(var, oldval, val) ATOMIC_CAS(var, oldval, val)
 #endif
 
+#if RUBY_ATOMIC_GENERIC_MACRO
+# ifndef ATOMIC_PTR_EXCHANGE
+#   define ATOMIC_PTR_EXCHANGE(var, val) ATOMIC_EXCHANGE(var, val)
+# endif
+# ifndef ATOMIC_PTR_CAS
+#   define ATOMIC_PTR_CAS(var, oldval, newval) ATOMIC_CAS(var, oldval, newval)
+# endif
+
+# ifndef ATOMIC_VALUE_EXCHANGE
+#   define ATOMIC_VALUE_EXCHANGE(var, val) ATOMIC_EXCHANGE(var, val)
+# endif
+# ifndef ATOMIC_VALUE_CAS
+#   define ATOMIC_VALUE_CAS(var, oldval, val) ATOMIC_CAS(var, oldval, newval)
+# endif
+#endif
+
 #ifndef ATOMIC_PTR_EXCHANGE
 # if SIZEOF_VOIDP == SIZEOF_SIZE_T
 #   define ATOMIC_PTR_EXCHANGE(var, val) (void *)ATOMIC_SIZE_EXCHANGE(*(size_t *)&(var), (size_t)(val))
+# else
+#   define ATOMIC_PTR_EXCHANGE(var, val) ruby_atomic_ptr_exchange((const void **)&(var), (val))
+static inline void *
+ruby_atomic_ptr_exchange(const void **ptr, const void *val)
+{
+    const void *const old = *ptr;
+    *ptr = val;
+    return (void *)old;
+}
 # endif
 #endif
 #ifndef ATOMIC_PTR_CAS
 # if SIZEOF_VOIDP == SIZEOF_SIZE_T
 #   define ATOMIC_PTR_CAS(var, oldval, val) (void *)ATOMIC_SIZE_CAS(*(size_t *)&(var), (size_t)(oldval), (size_t)(val))
+# else
+#   define ATOMIC_PTR_CAS(var, oldval, val) ruby_atomic_ptr_cas(&(var), (oldval), (val))
+static inline void *
+ruby_atomic_ptr_cas(const void **ptr, const void *oldval, const void *val)
+{
+    const void *const old = *ptr;
+    if (old == oldval) *ptr = val;
+    return (void *)old;
+}
+# endif
+#endif
+
+#ifndef ATOMIC_VALUE_EXCHANGE
+# if SIZEOF_VALUE == SIZEOF_SIZE_T
+#   define ATOMIC_VALUE_EXCHANGE(var, val) ATOMIC_SIZE_EXCHANGE(*(size_t *)&(var), (size_t)(val))
+# else
+#   define ATOMIC_VALUE_EXCHANGE(var, val) ruby_atomic_value_exchange(&(var), (val))
+static inline VALUE
+ruby_atomic_value_exchange(VALUE *ptr, VALUE val)
+{
+    const VALUE old = *ptr;
+    *ptr = val;
+    return old;
+}
+# endif
+#endif
+#ifndef ATOMIC_VALUE_CAS
+# if SIZEOF_VALUE == SIZEOF_SIZE_T
+#   define ATOMIC_VALUE_CAS(var, oldval, val) ATOMIC_SIZE_CAS(*(size_t *)&(var), (size_t)(oldval), (size_t)(val))
+# else
+#   define ATOMIC_VALUE_CAS(var, oldval, val) ruby_atomic_value_cas(&(var), (oldval), (val))
+static inline VALUE
+ruby_atomic_value_cas(VALUE *ptr, VALUE oldval, VALUE val)
+{
+    const VALUE old = *ptr;
+    if (old == oldval) *ptr = val;
+    return old;
+}
 # endif
 #endif