Levente

I think that the first step is not to make sure that you cannot hack inside literals like mad. But to make sure that in
99.99 % of the case, this assumption can hold.

Stef

On 27/10/14 15:46, Levente Uzonyi wrote:

 
On Mon, 27 Oct 2014, Eliot Miranda wrote:

I disagree. It's about an incremental improvement. A per-object
immutability bit used to protect against direct alteration of literals works. Right now there's nothing to stop one recompiling a method, and
per-object immutability doesn't change that. So mutable compiled methods are tolerable (at least in VW we kept methods mutable). But having the bit stop direct modification of literals is goodness, not to
be avoided because it doesn't prevent more exotic modification via become.

But if you allow mutable CompiledMethods, then Clement's example can be rewritten as:

MyClass >> #foo

    ^#(false) first
        ifFalse: [
            'first call since compilation' logCr.
            thisContext method in: [ :method |
                (method literalAt: (method literals indexOf: #(false)) put: { true }) ] ]
        ifTrue: [ 'other calls' logCr ]

(#becomeForward: could also be used on the literal).

How will you avoid implementing the deoptimization of the method (the slow path) when this is possible?

Levente