1438108 - [Static Analysis][Logically dead code] in RestyleManager::ChangeHintToString

Status: RESOLVED WONTFIX

(Core :: Layout, enhancement, P3)

Description

[Sylvestre Ledru [:Sylvestre]]

Coverity thinks that rest = 0:
  uint32_t rest = aHint & ~static_cast<uint32_t>((1ull << ArrayLength(names)) - 1);

Causing code to be dead code:
https://searchfox.org/mozilla-central/source/layout/base/RestyleManager.cpp#472-475

Comment 1

[Sylvestre Ledru [:Sylvestre]]

Hiroyuki, do you agree with this?

Comment 2

[Hiroyuki Ikezoe (:hiro)]

Oh right, indeed.  I didn't notice it.  But it will be used when we need to expand change hints to uint64_t, so I don't think it's not a big deal.

Comment 3

[Jet Villegas (inactive)]

[ Triage 2017/02/20: P3 ]

Comment 4

[Manish [:manishkk]]

need to remove this code only
https://searchfox.org/mozilla-central/source/layout/base/RestyleManager.cpp#472-475

or anything else to do?

Comment 5

[Cameron McCormack (:heycam)]

Manish, the code from the original report has moved (since the link was to current tip rather than whatever commit Coverity was run on), and should be this:

https://searchfox.org/mozilla-central/rev/5a744713370ec47969595e369fd5125f123e6d24/layout/base/RestyleManager.cpp#630-633

But as Hiro mentions, this is not a problem, given it was meant to handle how ever many change hint bits we currently use.

It doesn't seem worth trying to avoid the warning by changing the code.  Sylvestre, can we whitelist this warning?

Comment 6

[Sylvestre Ledru [:Sylvestre]]

Done, sorry Manish!