0007229: Remove optimisation for >>class

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Severity

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Date Submitted

Last Update

0007229

[Squeak] VM

tweak

always

11-19-08 23:27

01-09-11 23:01

Reporter

mikevdg

View Status

public

Assigned To

lewis

Priority

normal

Resolution

open

Status

assigned

Product Version

3.10.2

Summary

0007229: Remove optimisation for >>class

Description

The VM uses bytecode 199 to send >>class; the implementation is optimised to not do a message send but to return the class directly.

In some cases such as using message catchers (i.e. the trick where you override >>doesNotUnderstand on a ProtoObject subclass), this is undesired behaviour. The optimisation prevents the user from being able to override the behaviour of >>class.

(code below from Eliot Miranda)

To fix this change
bytecodePrimClass
| rcvr |
rcvr := self internalStackTop.
self internalPop: 1 thenPush: (self fetchClassOf: rcvr).
self fetchNextBytecode.
to
bytecodePrimClass
messageSelector := self specialSelector: 23.
argumentCount := 0.
self normalSend.

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Issue History
Date Modified	Username	Field	Change
11-19-08 23:27	mikevdg	New Issue
11-19-08 23:27	mikevdg	Status	new => assigned
11-19-08 23:27	mikevdg	Assigned To	=> tim
11-20-08 11:55	lewis	Issue Monitored: lewis
01-09-11 23:01	lewis	Assigned To	tim => lewis

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