New mark table implementation

Automatically generate a table containing the data where JS Values
and pointers are in objects in the JS heap.

This will allow making the GC mark phase a lot more efficient.

A bit of a special hack is currently required for MemberData and
ArrayData, as they have a variable length, and we need to read the
size from the object.

We keep backwards compatibility with the old markObjects() functions
for now (calling them if they are defined). Some further work on
QV4::String and in a few other places is required before we can get
remove the compatibility.

Change-Id: I78528ace67e886bdbe4a4330c9677c7fc9f08a33
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 6 insertions, 8 deletions

diff --git a/src/qml/jsruntime/qv4memberdata_p.h b/src/qml/jsruntime/qv4memberdata_p.h
index 5c89dfe8ec..c4e797ff8d 100644
--- a/src/qml/jsruntime/qv4memberdata_p.h
+++ b/src/qml/jsruntime/qv4memberdata_p.h
@@ -59,12 +59,12 @@ namespace QV4 {
 
 namespace Heap {
 
-struct MemberData : Base {
-    union {
-        uint size;
-        double _dummy;
-    };
-    Value data[1];
+#define MemberDataMembers(class, Member) \
+    Member(class, uint, size) \
+    Member(class, ValueArray, data)
+
+DECLARE_HEAP_OBJECT(MemberData, Base) {
+    DECLARE_MARK_TABLE(MemberData);
 };
 V4_ASSERT_IS_TRIVIAL(MemberData)
 
@@ -80,8 +80,6 @@ struct MemberData : Managed
     inline uint size() const { return d()->size; }
 
     static Heap::MemberData *allocate(QV4::ExecutionEngine *e, uint n, Heap::MemberData *old = 0);
-
-    static void markObjects(Heap::Base *that, ExecutionEngine *e);
 };
 
 }