Further work towards an exact GC

Add some more convenience in the helper classes
in qscopedvalue_p.h
Make accesses to CallData safer, and change
ExecutionEngine::newObject() to return a safe
pointer.

Change-Id: I980909754ce9681cf6faa1355bab3a1e5d6dd186
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Don't use Value::emptyValue() anymore.

emptyValue is special and reserved for usage inside the
engine to mark missing values. The main to use cases
are when converting property descriptors, and to mark
holes in array data.

Change-Id: I0ed357e65102b1041bf9a878e6e9a4ae0657523b
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Cleanup ExecutionEngine::newBuiltinFunction() usages

And change the return type to be GC safe

Change-Id: I6d7513962370fea4072a3d8c6b2c6f2d1705992e
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Introduce a Referenced<T> class to pass Objects into methods

Added some convenience typedefs (StringRef, ObjectRef, ReturnedString,
ScopedString, ...)
Used StringRef in newBuiltinFunction() for testing.
Cleaned up the duplicated code for thrower functions.

Change-Id: I7b7676690cbe70d9eabb0a5afd0d922f0be3aefd
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Start using StringRef for parameter passing

Change-Id: If2c41daeda2862cd1162c5da8163a9d62fe4111d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Add a Safe<T> class and start using it

The class denotes objects that are stored safely
in areas controlled by the GC. These we can convert
fast to a StringRef etc.

Change-Id: I6b154eccaefddc42d4fafca55b7ee9e77179830c
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Cleanup Object::define*Property API

Change-Id: I99125908a9bc1d41a2642c409af9704def7a0832
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Use StringRef for most methods in Object

Change-Id: I8e2dad0e9e34c5a549952bc0765cd57f6aa8aadf
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Use a StringRef for Managed::get()

also store "toString" and "valueOf" as identifiers
in the engine and fix two places where we compared
strings the wrong way.

Change-Id: I70612221e72d43ed0e3c496e4209681bf254cded
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
convert Managed::put() API to be GC safe

Change-Id: I09198ce372fa545372db389fac26828d21ad5731
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Convert putIndexed()

Change-Id: I7d02b0fdf45079d0f7afcfb6d3158dd60cb09f33
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Convert the remaining vtable methods to be GC safe

Change-Id: I679d1833609c41d71e8436ec0ba8a4624f0c4dd0
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Convert Object::inplaceBinOp to be GC safe

Change-Id: I98a8591f4b556cc1d00271e6b389dc0d2c16e6ec
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
remove debug output

Change-Id: I168f24ac12715fc65abe230b2bd0f86f777eea00
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Change the runtime API over to using StringRef's instead of String*

Change-Id: I0ea95e6cca995dc5f98871f0369204af18e48111
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Make sure ScopedArrayObject works as intended

We need a proper cast method for the class.

Change-Id: I8f2e4b3201d70e8fc90148f1780fd377057947bb
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Fix some smaller spec incompliances in Array.concat

Change-Id: I4a2252ef590c0d48ba734f96c7478637e1ddfd07
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Fix some more methods to take ValueRef's

Change-Id: Ia0e30ba98c16e51c9992027c7e5f78d4def8697a
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Convert the last methods in qv4object_p.h

Change-Id: I4fda83a0832760c277e629d4e658da718c0bf92b
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Prevent objects from being collected while in their constructor

While objects are being constructed, we don't have a reference to them
on the JS stack yet. So the constructor needs to protect itself against
being collected by putting the this object onto the JS stack.

Added an environment switch MM_EXACT_GC to test exact garbage
collection.

Change-Id: Ie37665a954de800359c272ffbebbe1488e7a8ace
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>