refactoring thread inits in vm.c

* `th_init` accepts vm and ractor.
* remove `ruby_thread_init` because it is duplicated with `th_init`.
* add some comments.

1 files changed, 22 insertions, 30 deletions

diff --git a/vm.c b/vm.c
index f5016f6dec..8cec781f7a 100644
--- a/vm.c
+++ b/vm.c
@@ -3247,9 +3247,12 @@ rb_ec_clear_vm_stack(rb_execution_context_t *ec)
 }
 
 static void
-th_init(rb_thread_t *th, VALUE self)
+th_init(rb_thread_t *th, VALUE self, rb_vm_t *vm, rb_ractor_t *r)
 {
     th->self = self;
+    th->vm = vm;
+    th->ractor = r;
+
     rb_threadptr_root_fiber_setup(th);
 
     /* All threads are blocking until a non-blocking fiber is scheduled */
@@ -3257,7 +3260,7 @@ th_init(rb_thread_t *th, VALUE self)
     th->scheduler = Qnil;
 
     if (self == 0) {
-        size_t size = th->vm->default_params.thread_vm_stack_size / sizeof(VALUE);
+        size_t size = vm->default_params.thread_vm_stack_size / sizeof(VALUE);
         rb_ec_initialize_vm_stack(th->ec, ALLOC_N(VALUE, size), size);
     }
     else {
@@ -3268,47 +3271,33 @@ th_init(rb_thread_t *th, VALUE self)
 
     th->status = THREAD_RUNNABLE;
     th->last_status = Qnil;
-    th->ec->errinfo = Qnil;
-    th->ec->root_svar = Qfalse;
-    th->ec->local_storage_recursive_hash = Qnil;
-    th->ec->local_storage_recursive_hash_for_trace = Qnil;
+    th->top_wrapper = 0;
+    th->top_self = vm->top_self; // 0 while self == 0
+    th->value = Qundef;
+
 #ifdef NON_SCALAR_THREAD_ID
     th->thread_id_string[0] = '\0';
 #endif
 
-    th->value = Qundef;
+    th->ec->errinfo = Qnil;
+    th->ec->root_svar = Qfalse;
+    th->ec->local_storage_recursive_hash = Qnil;
+    th->ec->local_storage_recursive_hash_for_trace = Qnil;
 
 #if OPT_CALL_THREADED_CODE
     th->retval = Qundef;
 #endif
     th->name = Qnil;
-    th->report_on_exception = th->vm->thread_report_on_exception;
+    th->report_on_exception = vm->thread_report_on_exception;
     th->ext_config.ractor_safe = true;
 }
 
-static VALUE
-ruby_thread_init(VALUE self)
-{
-    rb_thread_t *th = GET_THREAD();
-    rb_thread_t *target_th = rb_thread_ptr(self);
-    rb_vm_t *vm = th->vm;
-
-    target_th->vm = vm;
-    th_init(target_th, self);
-
-    target_th->top_wrapper = 0;
-    target_th->top_self = rb_vm_top_self();
-    target_th->ec->root_svar = Qfalse;
-    target_th->ractor = th->ractor;
-
-    return self;
-}
-
 VALUE
 rb_thread_alloc(VALUE klass)
 {
     VALUE self = thread_alloc(klass);
-    ruby_thread_init(self);
+    rb_thread_t *target_th = rb_thread_ptr(self);
+    th_init(target_th, self, GET_VM(), GET_RACTOR());
     return self;
 }
 
@@ -3946,6 +3935,8 @@ Init_BareVM(void)
 	fputs("[FATAL] failed to allocate memory\n", stderr);
 	exit(EXIT_FAILURE);
     }
+
+    // setup the VM
     MEMZERO(th, rb_thread_t, 1);
     vm_init2(vm);
 
@@ -3955,13 +3946,14 @@ Init_BareVM(void)
     vm->overloaded_cme_table = st_init_numtable();
     vm->constant_cache = rb_id_table_create(0);
 
+    // setup main thread
     Init_native_thread(th);
-    th->vm = vm;
-    th_init(th, 0);
-    vm->ractor.main_ractor = th->ractor = rb_ractor_main_alloc();
+    th_init(th, 0, vm, vm->ractor.main_ractor = rb_ractor_main_alloc());
+
     rb_ractor_set_current_ec(th->ractor, th->ec);
     ruby_thread_init_stack(th);
 
+    // setup ractor system
     rb_native_mutex_initialize(&vm->ractor.sync.lock);
     rb_native_cond_initialize(&vm->ractor.sync.barrier_cond);
     rb_native_cond_initialize(&vm->ractor.sync.terminate_cond);