`nt->serial` for `RUBY_DEBUG_LOG`

Show native thread's serial on `RUBY_DEBUG_LOG`.
`nt->serial` is also stored into `ruby_nt_serial` if the compiler
supports `RB_THREAD_LOCAL_SPECIFIER`.

4 files changed, 65 insertions, 16 deletions

diff --git a/debug.c b/debug.c
index f1b83714d8..60cd52ad13 100644
--- a/debug.c
+++ b/debug.c
@@ -533,7 +533,9 @@ ruby_debug_log(const char *file, int line, const char *func_name, const char *fm
         len += r;
     }
 
-    if (rb_current_execution_context(false)) {
+    rb_execution_context_t *ec = rb_current_execution_context(false);
+
+    if (ec) {
         // Ruby location
         int ruby_line;
         const char *ruby_file = rb_source_location_cstr(&ruby_line);
@@ -547,22 +549,46 @@ ruby_debug_log(const char *file, int line, const char *func_name, const char *fm
             if (r < 0) rb_bug("ruby_debug_log returns %d\n", r);
             len += r;
         }
+    }
+
+#ifdef RUBY_NT_SERIAL
+    // native thread information
+    if (len < MAX_DEBUG_LOG_MESSAGE_LEN) {
+        r = snprintf(buff + len, MAX_DEBUG_LOG_MESSAGE_LEN - len, "\tnt:%d", ruby_nt_serial);
+        if (r < 0) rb_bug("ruby_debug_log returns %d\n", r);
+        len += r;
+    }
+#endif
+
+    if (ec) {
+        rb_thread_t *th = ec ? rb_ec_thread_ptr(ec) : NULL;
 
         // ractor information
         if (ruby_single_main_ractor == NULL) {
-            rb_ractor_t *cr = GET_RACTOR();
+            rb_ractor_t *cr = th ? th->ractor : NULL;
+
             if (r && len < MAX_DEBUG_LOG_MESSAGE_LEN) {
-                r = snprintf(buff + len, MAX_DEBUG_LOG_MESSAGE_LEN - len, "\tr:#%u/%u",
-                             (unsigned int)rb_ractor_id(cr), GET_VM()->ractor.cnt);
+                r = snprintf(buff + len, MAX_DEBUG_LOG_MESSAGE_LEN - len, "\tr:#%d/%u",
+                             cr ? (int)rb_ractor_id(cr) : -1, GET_VM()->ractor.cnt);
+
                 if (r < 0) rb_bug("ruby_debug_log returns %d\n", r);
                 len += r;
             }
         }
 
         // thread information
-        const rb_thread_t *th = GET_THREAD();
-        if (r && len < MAX_DEBUG_LOG_MESSAGE_LEN) {
-            r = snprintf(buff + len, MAX_DEBUG_LOG_MESSAGE_LEN - len, "\tth:%u", rb_th_serial(th));
+        if (th && r && len < MAX_DEBUG_LOG_MESSAGE_LEN) {
+            rb_execution_context_t *rec = th->ractor ? th->ractor->threads.running_ec : NULL;
+            const rb_thread_t *rth = rec ? rec->thread_ptr : NULL;
+            const rb_thread_t *sth = th->ractor ? th->ractor->threads.sched.running : NULL;
+
+            if (rth != th || sth != th) {
+                r = snprintf(buff + len, MAX_DEBUG_LOG_MESSAGE_LEN - len, "\tth:%u (rth:%d,sth:%d)",
+                             rb_th_serial(th), rth ? (int)rb_th_serial(rth) : -1, sth ? (int)rb_th_serial(sth) : -1);
+            }
+            else {
+                r = snprintf(buff + len, MAX_DEBUG_LOG_MESSAGE_LEN - len, "\tth:%u", rb_th_serial(th));
+            }
             if (r < 0) rb_bug("ruby_debug_log returns %d\n", r);
             len += r;
         }
diff --git a/thread_pthread.c b/thread_pthread.c
index d5a00ff84a..9fe561a789 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -1157,6 +1157,11 @@ static void *
 thread_start_func_1(void *th_ptr)
 {
     rb_thread_t *th = th_ptr;
+
+#if USE_RUBY_DEBUG_LOG && defined(RUBY_NT_SERIAL)
+    ruby_nt_serial = th->nt->serial;
+#endif
+
     RB_ALTSTACK_INIT(void *altstack, th->nt->altstack);
 #if USE_THREAD_CACHE
   thread_start:
@@ -1298,13 +1303,24 @@ clear_thread_cache_altstack(void)
 }
 #endif
 
+static struct rb_native_thread *
+native_thread_alloc(void)
+{
+    struct rb_native_thread *nt = ZALLOC(struct rb_native_thread);
+#if USE_RUBY_DEBUG_LOG
+    static rb_atomic_t nt_serial = 1;
+    nt->serial = RUBY_ATOMIC_FETCH_ADD(nt_serial, 1);
+#endif
+    return nt;
+}
+
 static int
 native_thread_create(rb_thread_t *th)
 {
     int err = 0;
 
     VM_ASSERT(th->nt == 0);
-    th->nt = ZALLOC(struct rb_native_thread);
+    th->nt = native_thread_alloc();
 
     if (use_cached_thread(th)) {
         RUBY_DEBUG_LOG("use cached nt. th:%u", rb_th_serial(th));
diff --git a/thread_pthread.h b/thread_pthread.h
index 0f8e4d6096..40d7a13aa0 100644
--- a/thread_pthread.h
+++ b/thread_pthread.h
@@ -26,7 +26,7 @@ struct rb_thread_sched_item {
 };
 
 struct rb_native_thread {
-    int id;
+    rb_atomic_t serial;
 
     rb_nativethread_id_t thread_id;
 
@@ -101,13 +101,17 @@ struct rb_thread_sched {
 
 RUBY_SYMBOL_EXPORT_BEGIN
 #ifdef RB_THREAD_LOCAL_SPECIFIER
-# ifdef __APPLE__
-// on Darwin, TLS can not be accessed across .so
-struct rb_execution_context_struct *rb_current_ec(void);
-void rb_current_ec_set(struct rb_execution_context_struct *);
-# else
-RUBY_EXTERN RB_THREAD_LOCAL_SPECIFIER struct rb_execution_context_struct *ruby_current_ec;
-# endif
+  # ifdef __APPLE__
+    // on Darwin, TLS can not be accessed across .so
+    struct rb_execution_context_struct *rb_current_ec(void);
+    void rb_current_ec_set(struct rb_execution_context_struct *);
+  # else
+    RUBY_EXTERN RB_THREAD_LOCAL_SPECIFIER struct rb_execution_context_struct *ruby_current_ec;
+
+    // for RUBY_DEBUG_LOG()
+    RUBY_EXTERN RB_THREAD_LOCAL_SPECIFIER rb_atomic_t ruby_nt_serial;
+    #define RUBY_NT_SERIAL 1
+  # endif
 #else
 typedef pthread_key_t native_tls_key_t;
 
diff --git a/vm.c b/vm.c
index 69d57913a4..eb60d3792d 100644
--- a/vm.c
+++ b/vm.c
@@ -440,6 +440,9 @@ bool ruby_vm_keep_script_lines;
 
 #ifdef RB_THREAD_LOCAL_SPECIFIER
 RB_THREAD_LOCAL_SPECIFIER rb_execution_context_t *ruby_current_ec;
+#ifdef RUBY_NT_SERIAL
+RB_THREAD_LOCAL_SPECIFIER rb_atomic_t ruby_nt_serial;
+#endif
 
 #ifdef __APPLE__
   rb_execution_context_t *