From bf1c4d254beb0e01fac1d9e6cb805de8ec6260eb Mon Sep 17 00:00:00 2001
From: Yuta Saito <kateinoigakukun@gmail.com>
Date: Sat, 15 Jan 2022 23:59:37 +0900
Subject: [PATCH] [wasm] gc.c: scan wasm locals and c stack to mark living
 objects

WebAssembly has function local infinite registers and stack values, but
there is no way to scan the values in a call stack for now.
This implementation uses Asyncify to spilling out wasm locals into
linear memory.
---
 gc.c | 61 +++++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 40 insertions(+), 21 deletions(-)

diff --git a/gc.c b/gc.c
index 2fa4eabc41..b87c72a477 100644
--- a/gc.c
+++ b/gc.c
@@ -30,6 +30,7 @@
 
 #if defined(__wasm__) && !defined(__EMSCRIPTEN__)
 # include "wasm/setjmp.h"
+# include "wasm/machine.h"
 #else
 # include <setjmp.h>
 #endif
@@ -6504,7 +6505,45 @@ mark_const_tbl(rb_objspace_t *objspace, struct rb_id_table *tbl)
 static void each_stack_location(rb_objspace_t *objspace, const rb_execution_context_t *ec,
                                  const VALUE *stack_start, const VALUE *stack_end, void (*cb)(rb_objspace_t *, VALUE));
 
-#ifndef __EMSCRIPTEN__
+#if defined(__wasm__)
+
+
+static VALUE *rb_stack_range_tmp[2];
+
+static void
+rb_mark_locations(void *begin, void *end)
+{
+    rb_stack_range_tmp[0] = begin;
+    rb_stack_range_tmp[1] = end;
+}
+
+# if defined(__EMSCRIPTEN__)
+
+static void
+mark_current_machine_context(rb_objspace_t *objspace, rb_execution_context_t *ec)
+{
+    emscripten_scan_stack(rb_mark_locations);
+    each_stack_location(objspace, ec, rb_stack_range_tmp[0], rb_stack_range_tmp[1], gc_mark_maybe);
+
+    emscripten_scan_registers(rb_mark_locations);
+    each_stack_location(objspace, ec, rb_stack_range_tmp[0], rb_stack_range_tmp[1], gc_mark_maybe);
+}
+# else // use Asyncify version
+
+static void
+mark_current_machine_context(rb_objspace_t *objspace, rb_execution_context_t *ec)
+{
+    rb_wasm_scan_stack(rb_mark_locations);
+    each_stack_location(objspace, ec, rb_stack_range_tmp[0], rb_stack_range_tmp[1], gc_mark_maybe);
+
+    rb_wasm_scan_locals(rb_mark_locations);
+    each_stack_location(objspace, ec, rb_stack_range_tmp[0], rb_stack_range_tmp[1], gc_mark_maybe);
+}
+
+# endif
+
+#else // !defined(__wasm__)
+
 static void
 mark_current_machine_context(rb_objspace_t *objspace, rb_execution_context_t *ec)
 {
@@ -6529,26 +6568,6 @@ mark_current_machine_context(rb_objspace_t *objspace, rb_execution_context_t *ec
 
     each_stack_location(objspace, ec, stack_start, stack_end, gc_mark_maybe);
 }
-#else
-
-static VALUE *rb_emscripten_stack_range_tmp[2];
-
-static void
-rb_emscripten_mark_locations(void *begin, void *end)
-{
-    rb_emscripten_stack_range_tmp[0] = begin;
-    rb_emscripten_stack_range_tmp[1] = end;
-}
-
-static void
-mark_current_machine_context(rb_objspace_t *objspace, rb_execution_context_t *ec)
-{
-    emscripten_scan_stack(rb_emscripten_mark_locations);
-    each_stack_location(objspace, ec, rb_emscripten_stack_range_tmp[0], rb_emscripten_stack_range_tmp[1], gc_mark_maybe);
-
-    emscripten_scan_registers(rb_emscripten_mark_locations);
-    each_stack_location(objspace, ec, rb_emscripten_stack_range_tmp[0], rb_emscripten_stack_range_tmp[1], gc_mark_maybe);
-}
 #endif
 
 static void