283082 - Arithmetic overflow warning in js/src/jsinterp.c

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[David Gardiner]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0

Running PREfast static code analysis gives the following warning:

jsinterp.c(2916) : warning 297: Arithmetic overflow: 32-bit value is shifted,
then cast to 64-bit value. Cast to a 64-bit value before the shift. Bits may be
lost.
problem occurs in function 'js_Interpret'

The warning line is:

SIGNED_SHIFT_OP(<<);

Apologies if this is a false alarm.

-dave

Reproducible: Always

Steps to Reproduce:

Comment 1

[Brendan Eich [:brendan]]

Please don't file bogus bugs.  Tools needs humans inspecting their results, and
filtering out invalid claims to save other humans from wasting time.

/be

Comment 2

[David Gardiner]

I apologise (again). PREfast has been quite accurate at finding quite a few
other issues in the Mozilla code. I try to only file bugs against warnings that
look reasonable (there are a few that it does get wrong)

I don't know this code as well as you do, so I do appreciate you marking it as
invalid.

-dave