separate Thread type (func or proc) explicitly.

* vm_core.h (rb_thread_struct): introduce new fields `invoke_type`
  and `invoke_arg`.
  There are two types threads: invoking proc (normal Ruby thread
  created by `Thread.new do ... end`) and invoking func, created
  by C-API. `invoke_type` shows the types.

* thread.c (thread_do_start): copy `invoke_arg.proc.args` contents
  from Array to ALLOCA stack memory if args length is enough small (<8).
  We don't need to keep Array and don't need to cancel using transient heap.

* vm.c (thread_mark): For func invoking threads, they can pass (void *)
  parameter (rb_thread_t::invoke_arg::func::arg). However, a rubyspec test
  (thread_spec.c) passes an Array object and it expect to mark it.
  Clealy it is out of scope (misuse of `rb_thread_create` C-API). However,
  I'm not sure someone else has such kind of misunderstanding.
  So now we mark conservatively this (void *) arg with rb_gc_mark_maybe.

  This misuse is found by this error log.
  http://ci.rvm.jp/results/trunk-theap-asserts@silicon-docker/1448164


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65622 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 16 insertions, 3 deletions

diff --git a/vm_core.h b/vm_core.h
index e5fdba44b9..faab30b1d7 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -936,9 +936,22 @@ typedef struct rb_thread_struct {
 
     rb_thread_list_t *join_list;
 
-    VALUE first_proc;
-    VALUE first_args;
-    VALUE (*first_func)(ANYARGS);
+    union {
+        struct {
+            VALUE proc;
+            VALUE args;
+        } proc;
+        struct {
+            VALUE (*func)(ANYARGS);
+            void *arg;
+        } func;
+    } invoke_arg;
+
+    enum {
+        thread_invoke_type_none = 0,
+        thread_invoke_type_proc,
+        thread_invoke_type_func,
+    } invoke_type;
 
     /* statistics data for profiler */
     VALUE stat_insn_usage;