Introduce Ractor mechanism for parallel execution

This commit introduces Ractor mechanism to run Ruby program in
parallel. See doc/ractor.md for more details about Ractor.
See ticket [Feature #17100] to see the implementation details
and discussions.

[Feature #17100]

This commit does not complete the implementation. You can find
many bugs on using Ractor. Also the specification will be changed
so that this feature is experimental. You will see a warning when
you make the first Ractor with `Ractor.new`.

I hope this feature can help programmers from thread-safety issues.

1 files changed, 96 insertions, 0 deletions

diff --git a/vm_sync.h b/vm_sync.h
new file mode 100644
index 0000000000..e9cc274bb8
--- /dev/null
+++ b/vm_sync.h
@@ -0,0 +1,96 @@
+
+#ifndef RUBY_VM_SYNC_H
+#define RUBY_VM_SYNC_H
+
+#include "vm_core.h"
+#include "vm_debug.h"
+
+#if USE_RUBY_DEBUG_LOG
+#define LOCATION_ARGS const char *file, int line
+#define LOCATION_PARAMS file, line
+#define APPEND_LOCATION_ARGS , const char *file, int line
+#define APPEND_LOCATION_PARAMS , file, line
+#else
+#define LOCATION_ARGS void
+#define LOCATION_PARAMS
+#define APPEND_LOCATION_ARGS
+#define APPEND_LOCATION_PARAMS
+#endif
+
+bool rb_vm_locked_p(void);
+void rb_vm_lock_body(LOCATION_ARGS);
+void rb_vm_unlock_body(LOCATION_ARGS);
+void rb_vm_lock_enter_body(unsigned int *lev APPEND_LOCATION_ARGS);
+void rb_vm_lock_leave_body(unsigned int *lev APPEND_LOCATION_ARGS);
+void rb_vm_barrier(void);
+void rb_vm_cond_wait(rb_vm_t *vm, rb_nativethread_cond_t *cond);
+void rb_vm_cond_timedwait(rb_vm_t *vm, rb_nativethread_cond_t *cond, unsigned long msec);
+
+extern bool ruby_multi_ractor;
+
+static inline bool
+rb_multi_ractor_p(void)
+{
+    if (LIKELY(!ruby_multi_ractor)) {
+        // 0 on boot time.
+        VM_ASSERT(GET_VM()->ractor.cnt <= 1);
+        return false;
+    }
+    else {
+        // multi-ractor mode can run ractor.cnt == 1
+        return true;
+    }
+}
+
+static inline void
+rb_vm_lock(const char *file, int line)
+{
+    if (rb_multi_ractor_p()) {
+        rb_vm_lock_body(LOCATION_PARAMS);
+    }
+}
+
+static inline void
+rb_vm_unlock(const char *file, int line)
+{
+    if (rb_multi_ractor_p()) {
+        rb_vm_unlock_body(LOCATION_PARAMS);
+    }
+}
+
+static inline void
+rb_vm_lock_enter(unsigned int *lev, const char *file, int line)
+{
+    if (rb_multi_ractor_p()) {
+        rb_vm_lock_enter_body(lev APPEND_LOCATION_PARAMS);
+    }
+}
+
+static inline void
+rb_vm_lock_leave(unsigned int *lev, const char *file, int line)
+{
+    if (rb_multi_ractor_p()) {
+        rb_vm_lock_leave_body(lev APPEND_LOCATION_PARAMS);
+    }
+}
+
+#define RB_VM_LOCKED_P()   rb_vm_locked_p()
+
+#define RB_VM_LOCK()       rb_vm_lock(__FILE__, __LINE__)
+#define RB_VM_UNLOCK()     rb_vm_unlock(__FILE__, __LINE__)
+
+#define RB_VM_LOCK_ENTER_LEV(levp) rb_vm_lock_enter(levp, __FILE__, __LINE__);
+#define RB_VM_LOCK_LEAVE_LEV(levp) rb_vm_lock_leave(levp, __FILE__, __LINE__);
+
+#define RB_VM_LOCK_ENTER()  { unsigned int _lev; RB_VM_LOCK_ENTER_LEV(&_lev);
+#define RB_VM_LOCK_LEAVE()    RB_VM_LOCK_LEAVE_LEV(&_lev); }
+
+#if VM_CHECK_MODE > 0
+void ASSERT_vm_locking(void);
+void ASSERT_vm_unlocking(void);
+#else
+#define ASSERT_vm_locking()
+#define ASSERT_vm_unlocking()
+#endif
+
+#endif // RUBY_VM_SYNC_H