1541943 - Revert clang back to 7 for Linux fuzzing builds that are used with libFuzzer

Status: RESOLVED FIXED

(Firefox Build System :: Task Configuration, defect)

Description

[Christian Holler (:decoder)]

Since the upgrade to Clang 8, our libFuzzer fuzzing is broken. Whenever we try to startup libFuzzer, we get

ERROR: The size of coverage PC tables does not match the
number of instrumented PCs. This might be a compiler bug,
please contact the libFuzzer developers.
Also check https://bugs.llvm.org/show_bug.cgi?id=34636
for possible workarounds (tl;dr: don't use the old GNU ld)

So far, I was neither able to reproduce this locally, nor able to fix it by upgrading our libFuzzer version.

I propose we downgrade to Clang 7 for the affected builds until we found the proper solution. I have a patch ready to do so.

Comment 1

[Christian Holler (:decoder)]

Attachment: Bug 1541943 - Temporarily switch libFuzzer builds back to clang-7. r?froydnj

Comment 2

[Christian Holler (:decoder)]

(In reply to Christian Holler (:decoder) from comment #1)

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=938a21dd000e6d845e7844090609fb2158be53fb

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/20750a2dc85b
Temporarily switch libFuzzer builds back to clang-7. r=froydnj

Comment 4

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/20750a2dc85b