475854 - if(false)'d function unnecessarily makes parent HEAVYWEIGHT

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[Jesse Ruderman]

js> print(dis(function(x) { if (false) { function y () {} } }));
flags: LAMBDA HEAVYWEIGHT INTERPRETED
main:
00000:  stop

Doesn't need to be HEAVYWEIGHT, because function y is gone.

Comment 1

[Jesse Ruderman]

Here's a case that I don't understand at all:

js> dis(function() { if (false) __proto__; })
flags: LAMBDA HEAVYWEIGHT INTERPRETED
main:
00000:  stop

Comment 2

[Mike Shaver (:shaver -- probably not reading bugmail closely)]

__proto__ is an undeclared access, so heavyweight.  Same bug, I suspect.

Comment 3

[Jesse Ruderman]

There's something weird going on in comment 1.  It only happens for the names "__proto__" and "__parent__".

Comment 4

[Blake Kaplan (:mrbkap) (inactive)]

See bug 36625. We mark the function heavyweight when we see the unqualified __proto__ or __parent__ and can't re-optimize easily.

Comment 5

[Luke Wagner [:luke]]

This is heavyweight because of the non-body-level function statement which dynamically adds 'y' to the scope.