771460 - IonMonkey: Remove register allocation for MIRType_ArgObj.

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Nicolas B. Pierron [:nbp — off until 29-09]]

Currently, ArgObj are runtime objects because it might have been useful to handle Argument Object which are not optimized value.  The current goal is to only handle the optimized value, thus there is no need to allocate a register for the optimized value.

Removing the allocation of the register implies that OSR should be modified to ensure that we have an optimized ArgObj as content of the slot and avoid the unboxing for this slot and provide a constant substitute for it.

This Bug should revert the modification made in Bug 765480 and the Unboxing made for ArgObj.  The MIRType_ArgObj might still be needed for the constant because the snapshot are not able to encode Magic Values because they are reusing the Magic tag to escape some special storage.

Comment 1

[David Anderson [:dvander] - inactive, e-mail if emergency]

I think this is deprecated by the MIRType_ArgObj removal.