1604023 - Firefox built with GCC 10 snapshots crashes due to Rust ABi compatibility bug

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Jan Hubicka]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

I build Firefox 71 release with GCC 10

Actual results:

It does crash for same reason as described in https://bugzilla.mozilla.org/show_bug.cgi?id=1600735

That bug was closed by updating fuzzer from gcc7 to gcc8, but that only hides the actual problem. As co-author of x86-64 PS ABI, I could confirm that the sign extensions was not intended to be required.

I wonder if this can be worked around by changing calling interface of this function until Rust compiler is updated?

Expected results:

It should have worked.

Comment 1

[Seba S.]

Hi, Jan Hubicka,

Thanks for your contribution!

I don´t have the technical knowledge to confirm this issue but I'll add product and component so the team can make some research on it. Hopefully, someone with a more deep understanding of this matter can help.

Regards,

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Yes... I have a WIP patch for this at https://reviews.llvm.org/D71178... We could workaround it taking a bigger type or something I guess, yeah.

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1604023 - Workaround LLVM ABI bug. r=#style,froydnj

All the gory details in https://bugzilla.mozilla.org/show_bug.cgi?id=1600735 and
related LLVM / GCC bugs. Avoid the issue by forcing the relevant enum to be
32-bit wide, so as to not trigger the LLVM bug.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Let me know if you want this uplifted? It should be trivial to do so.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/80d2d70a9bbd
Workaround LLVM ABI bug. r=froydnj

Comment 6

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/mozilla-central/rev/80d2d70a9bbd