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, 11 insertions, 5 deletions

diff --git a/src/qml/jsruntime/qv4arraydata_p.h b/src/qml/jsruntime/qv4arraydata_p.h
index 24b948f01e..919bd84762 100644
--- a/src/qml/jsruntime/qv4arraydata_p.h
+++ b/src/qml/jsruntime/qv4arraydata_p.h
@@ -90,7 +90,7 @@ struct ArrayVTable
 
 namespace Heap {
 
-struct ArrayData : public Base {
+struct ArrayDataData {
     enum Type {
         Simple = 0,
         Complex = 1,
@@ -110,6 +110,13 @@ struct ArrayData : public Base {
         SparseArray *sparse;
     };
     Value arrayData[1];
+};
+static Q_CONSTEXPR quint64 ArrayData_markTable = \
+        (MarkFlagsForType<decltype(ArrayDataData::arrayData)>::markFlags << (offsetof(ArrayDataData, arrayData) >> 2)) \
+        << (sizeof(Base) >> 2) | QV4::Heap::Base::markTable;
+
+struct ArrayData : public Base, ArrayDataData {
+    DECLARE_MARK_TABLE(ArrayData);
 
     bool isSparse() const { return type == Sparse; }
 
@@ -189,6 +196,9 @@ struct Q_QML_EXPORT ArrayData : public Managed
 {
     typedef Heap::ArrayData::Type Type;
     V4_MANAGED(ArrayData, Managed)
+    enum {
+        IsArrayData = true
+    };
 
     uint alloc() const { return d()->alloc; }
     uint &alloc() { return d()->alloc; }
@@ -246,8 +256,6 @@ struct Q_QML_EXPORT SimpleArrayData : public ArrayData
 
     static Heap::ArrayData *reallocate(Object *o, uint n, bool enforceAttributes);
 
-    static void markObjects(Heap::Base *d, ExecutionEngine *e);
-
     static ReturnedValue get(const Heap::ArrayData *d, uint index);
     static bool put(Object *o, uint index, const Value &value);
     static bool putArray(Object *o, uint index, const Value *values, uint n);
@@ -274,8 +282,6 @@ struct Q_QML_EXPORT SparseArrayData : public ArrayData
 
     uint mappedIndex(uint index) const { return d()->mappedIndex(index); }
 
-    static void markObjects(Heap::Base *d, ExecutionEngine *e);
-
     static Heap::ArrayData *reallocate(Object *o, uint n, bool enforceAttributes);
     static ReturnedValue get(const Heap::ArrayData *d, uint index);
     static bool put(Object *o, uint index, const Value &value);