Bug 1642154 : Add JSLinearString to MapTypeToTraceKind. r=jonco

Differential Revision: https://phabricator.services.mozilla.com/D78063

js/public/GCTypeMacros.h

@@ -28,10 +28,11 @@ class JS_PUBLIC_API Value;
 
 // Expand the given macro D for each public GC pointer.
 #define JS_FOR_EACH_PUBLIC_GC_POINTER_TYPE(D) \
-  D(JS::Symbol*)                              \
   D(JS::BigInt*)                              \
+  D(JS::Symbol*)                              \
   D(JSAtom*)                                  \
   D(JSFunction*)                              \
+  D(JSLinearString*)                          \
   D(JSObject*)                                \
   D(JSScript*)                                \
   D(JSString*)

js/public/TraceKind.h

@@ -12,6 +12,8 @@
 #include "js/TypeDecls.h"
 
 // Forward declarations of all the types a TraceKind can denote.
+class JSLinearString;
+
 namespace js {
 class BaseScript;
 class BaseShape;
@@ -144,6 +146,19 @@ inline constexpr bool IsBaseTraceType_v = IsBaseTraceType<T>::value;
 JS_FOR_EACH_TRACEKIND(JS_EXPAND_DEF);
 #undef JS_EXPAND_DEF
 
+template <>
+struct MapTypeToTraceKind<JSLinearString> {
+  static const JS::TraceKind kind = JS::TraceKind::String;
+};
+template <>
+struct MapTypeToTraceKind<JSFunction> {
+  static const JS::TraceKind kind = JS::TraceKind::Object;
+};
+template <>
+struct MapTypeToTraceKind<JSScript> {
+  static const JS::TraceKind kind = JS::TraceKind::Script;
+};
+
 // RootKind is closely related to TraceKind. Whereas TraceKind's indices are
 // laid out for convenient embedding as a pointer tag, the indicies of RootKind
 // are designed for use as array keys via EnumeratedArray.
@@ -203,11 +218,6 @@ template <>
 struct MapTypeToRootKind<jsid> {
   static const JS::RootKind kind = JS::RootKind::Id;
 };
-template <>
-struct MapTypeToRootKind<JSFunction*> : public MapTypeToRootKind<JSObject*> {};
-template <>
-struct MapTypeToRootKind<JSScript*>
-    : public MapTypeToRootKind<js::BaseScript*> {};
 
 // Fortunately, few places in the system need to deal with fully abstract
 // cells. In those places that do, we generally want to move to a layout