Fix makeGray misuse in GC (#2178)

std/assembly/rt/itcms.ts

@@ -148,6 +148,16 @@ function initLazy(space: Object): Object {
     this.unlink();
     this.linkTo(toSpace, this.isPointerfree ? i32(!white) : gray);
   }
+
+  /** Marks this object need to be scanned */
+  needScan(): void {
+    if (state == STATE_MARK) {
+      this.makeGray();
+    } else {
+      this.unlink();
+      this.linkTo(fromSpace, white);
+    }
+  }
 }
 
 /** Visits all objects considered to be program roots. */
@@ -301,10 +311,10 @@ export function __link(parentPtr: usize, childPtr: usize, expectMultiple: bool):
       if (expectMultiple) {
         // Move the barrier "backward". Suitable for containers receiving multiple stores.
         // Avoids a barrier for subsequent objects stored into the same container.
-        parent.makeGray();
+        parent.needScan();
       } else {
         // Move the barrier "forward". Suitable for objects receiving isolated stores.
-        child.makeGray();
+        child.needScan();
       }
     } else if (parentColor == transparent && state == STATE_MARK) {
       // Pinned objects are considered 'black' during the mark phase.
@@ -350,15 +360,7 @@ export function __unpin(ptr: usize): void {
   if (obj.color != transparent) {
     throw new Error(E_NOT_PINNED);
   }
-  if (state == STATE_MARK) {
-    // We may be right at the point after marking roots for the second time and
-    // entering the sweep phase, in which case the object would be missed if it
-    // is not only pinned but also a root. Make sure it isn't missed.
-    obj.makeGray();
-  } else {
-    obj.unlink();
-    obj.linkTo(fromSpace, white);
-  }
+  obj.needScan();
 }
 
 // @ts-ignore: decorator

tests/compiler/call-super.debug.wat

@@ -103,7 +103,7 @@
     if
      i32.const 0
      i32.const 144
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -1488,7 +1488,7 @@
     if
      i32.const 0
      i32.const 144
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable
@@ -2071,7 +2071,7 @@
   if
    i32.const 80
    i32.const 144
-   i32.const 260
+   i32.const 270
    i32.const 31
    call $~lib/builtins/abort
    unreachable

tests/compiler/call-super.release.wat

@@ -62,7 +62,7 @@
     if
      i32.const 0
      i32.const 1168
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -846,7 +846,7 @@
     if
      i32.const 0
      i32.const 1168
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable
@@ -1073,7 +1073,7 @@
   if
    i32.const 1104
    i32.const 1168
-   i32.const 260
+   i32.const 270
    i32.const 31
    call $~lib/builtins/abort
    unreachable

tests/compiler/class-implements.debug.wat

@@ -105,7 +105,7 @@
     if
      i32.const 0
      i32.const 96
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -1490,7 +1490,7 @@
     if
      i32.const 0
      i32.const 96
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable
@@ -2073,7 +2073,7 @@
   if
    i32.const 32
    i32.const 96
-   i32.const 260
+   i32.const 270
    i32.const 31
    call $~lib/builtins/abort
    unreachable

tests/compiler/class-implements.release.wat

@@ -76,7 +76,7 @@
     if
      i32.const 0
      i32.const 1120
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -860,7 +860,7 @@
     if
      i32.const 0
      i32.const 1120
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable

tests/compiler/class-overloading-cast.debug.wat

@@ -114,7 +114,7 @@
     if
      i32.const 0
      i32.const 96
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -1499,7 +1499,7 @@
     if
      i32.const 0
      i32.const 96
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable
@@ -2082,7 +2082,7 @@
   if
    i32.const 32
    i32.const 96
-   i32.const 260
+   i32.const 270
    i32.const 31
    call $~lib/builtins/abort
    unreachable

tests/compiler/class-overloading-cast.release.wat

@@ -98,7 +98,7 @@
     if
      i32.const 0
      i32.const 1120
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -882,7 +882,7 @@
     if
      i32.const 0
      i32.const 1120
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable

tests/compiler/class-overloading.debug.wat

@@ -120,7 +120,7 @@
     if
      i32.const 0
      i32.const 128
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -1505,7 +1505,7 @@
     if
      i32.const 0
      i32.const 128
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable
@@ -2088,7 +2088,7 @@
   if
    i32.const 64
    i32.const 128
-   i32.const 260
+   i32.const 270
    i32.const 31
    call $~lib/builtins/abort
    unreachable

tests/compiler/class-overloading.release.wat

@@ -122,7 +122,7 @@
     if
      i32.const 0
      i32.const 1152
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -906,7 +906,7 @@
     if
      i32.const 0
      i32.const 1152
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable

tests/compiler/class.debug.wat

@@ -216,7 +216,7 @@
     if
      i32.const 0
      i32.const 96
-     i32.const 159
+     i32.const 169
      i32.const 16
      call $~lib/builtins/abort
      unreachable
@@ -1601,7 +1601,7 @@
     if
      i32.const 0
      i32.const 96
-     i32.const 228
+     i32.const 238
      i32.const 20
      call $~lib/builtins/abort
      unreachable
@@ -2184,7 +2184,7 @@
   if
    i32.const 32
    i32.const 96
-   i32.const 260
+   i32.const 270
    i32.const 31
    call $~lib/builtins/abort
    unreachable
@@ -2227,6 +2227,22 @@
   memory.fill
   local.get $3
  )
+ (func $~lib/rt/itcms/Object#needScan (param $0 i32)
+  global.get $~lib/rt/itcms/state
+  i32.const 1
+  i32.eq
+  if
+   local.get $0
+   call $~lib/rt/itcms/Object#makeGray
+  else
+   local.get $0
+   call $~lib/rt/itcms/Object#unlink
+   local.get $0
+   global.get $~lib/rt/itcms/fromSpace
+   global.get $~lib/rt/itcms/white
+   call $~lib/rt/itcms/Object#linkTo
+  end
+ )
  (func $~lib/rt/itcms/__link (param $0 i32) (param $1 i32) (param $2 i32)
   (local $3 i32)
   (local $4 i32)
@@ -2243,7 +2259,7 @@
   if
    i32.const 0
    i32.const 96
-   i32.const 294
+   i32.const 304
    i32.const 14
    call $~lib/builtins/abort
    unreachable
@@ -2272,10 +2288,10 @@
     local.get $2
     if
      local.get $4
-     call $~lib/rt/itcms/Object#makeGray
+     call $~lib/rt/itcms/Object#needScan
     else
      local.get $3
-     call $~lib/rt/itcms/Object#makeGray
+     call $~lib/rt/itcms/Object#needScan
     end
    else
     local.get $5