349489 - Incorrect decompilation for labeled useless statements

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect, P1)

Description

[Jesse Ruderman]

When a function contains a labeled useless statement, decompilation puts the label on the next statement (or no statement, if there is no next statement).

> function() { L: 3; }
function () { L: }

> function() { L: }
SyntaxError on line 1: syntax error

> function() { L: 3; alert(5); }
function () { L: alert(5); }

Suggested fix:
(1) Don't optimize away labeled useless statements, or
(2) When optimizing away labeled useless statements, also remove the label.

Comment 1

[Brendan Eich [:brendan]]

Attachment: fix

mrbkap said r=him a few minutes ago.

/be

Comment 2

[Brendan Eich [:brendan]]

Drivers, this is another easy/safe fix.  I encouraged Jesse to fuzz JS at the statement level, and informed him about labeled statements and break to label (which were news to him, probably to others).  Here comes the fuzz!  Better late than never.

/be

Comment 3

[Brendan Eich [:brendan]]

Comment on attachment 234830 [details] [diff] [review]
fix

See previous comment.  Safe  and small fix.

/be

Comment 4

[Brendan Eich [:brendan]]

Fixed on trunk.

/be

Comment 5

[Bob Clary [:bc] (inactive)]

Checking in regress-349489.js;
/cvsroot/mozilla/js/tests/js1_5/Regress/regress-349489.js,v  <--  regress-349489.js
initial revision: 1.1

Comment 6

[Mike Schroepfer]

Comment on attachment 234830 [details] [diff] [review]
fix

a=schrep for drivers - approving all [181approval pending] bugs now that tree is open.

Comment 7

[Brendan Eich [:brendan]]

Fixed on the 1.8 branch.

/be

Comment 8

[Bob Clary [:bc] (inactive)]

verified fixed 1.8, 1.9 20060824 windows/mac*/linux