Looks like rust has switched to the 9.0.0 release branch, and its IR is incompatible with 8.0.0. We'll need to update our clang builds.

[task 2019-08-09T21:43:39.565Z] 21:43:39 INFO - lld-link: error: Unknown attribute kind (60) (Producer: 'LLVM9.0.0-rust-1.38.0-nightly' Reader: 'LLVM 8.0.0')

Updates all clang 8.0.1 to version 9.0.0, except for the mingw builds which suffer from bug 1548624 and will be handled separately later.

https://hg.mozilla.org/mozilla-central/rev/de0fe40466cb
https://hg.mozilla.org/mozilla-central/rev/587463567434

Backed out 2 changesets (bug 1573211) as requested by dmajor on irc

Backout: https://hg.mozilla.org/integration/autoland/rev/a3d9784a3b3326edc67c95699227b5fa684183d9

This push:
(In reply to Pulsebot from comment #3)

Pushed by bpostelnicu@mozilla.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/587463567434
MANUAL PUSH: Fix for Bug 1573211 - Re-generate the autotest results for
clang-tidy analysis. r=myself.

caused this improvement:
== Change summary for alert #23226 (as of Wed, 25 Sep 2019 22:42:03 GMT) ==

Improvements:

6% perf_reftest_singletons parent-basic-singleton.html windows7-32-shippable opt e10s stylo 99.80 -> 93.64

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23226

and this push:(In reply to Cristina Coroiu [:ccoroiu] from comment #5)

Backed out 2 changesets (bug 1573211) as requested by dmajor on irc

Backout: https://hg.mozilla.org/integration/autoland/rev/a3d9784a3b3326edc67c95699227b5fa684183d9

caused this regression:
== Change summary for alert #23249 (as of Thu, 26 Sep 2019 19:07:31 GMT) ==

Regressions:

7% perf_reftest_singletons parent-basic-singleton.html windows7-32-shippable opt e10s stylo 93.73 -> 100.15

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23249

Backout merged: https://hg.mozilla.org/mozilla-central/rev/a3d9784a3b33

This also caused regressions on Raptor

== Change summary for alert #23260 (as of Fri, 27 Sep 2019 09:06:52 GMT) ==

Regressions:

8% raptor-tp6-linkedin-firefox fcp linux64-shippable opt 436.35 -> 472.27

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23260

And the downstream in Autoland
== Change summary for alert #23239 (as of Thu, 26 Sep 2019 10:35:40 GMT) ==

Regressions:

7% raptor-tp6-linkedin-firefox fcp linux64-shippable opt 434.48 -> 464.04
6% raptor-tp6-linkedin-firefox fcp linux64-shippable-qr opt 458.58 -> 488.04
6% raptor-tp6-linkedin-firefox linux64-shippable opt 554.01 -> 586.30
6% raptor-tp6-linkedin-firefox linux64-shippable-qr opt 586.28 -> 619.39
4% raptor-tp6-yahoo-mail-firefox loadtime linux64-shippable-qr opt 425.31 -> 444.29
4% raptor-tp6-yandex-firefox loadtime linux64-shippable opt 206.60 -> 214.08
4% raptor-tp6-google-mail-firefox loadtime linux64-shippable opt 410.58 -> 425.42
3% raptor-tp6-facebook-firefox linux64-shippable-qr opt 310.92 -> 321.46
3% raptor-tp6-yahoo-news-firefox fcp linux64-shippable-qr opt 346.58 -> 357.75
3% raptor-tp6-netflix-firefox linux64-shippable-qr opt 427.40 -> 439.42
3% raptor-tp6-imgur-firefox loadtime linux64-shippable-qr opt 396.17 -> 407.21
3% raptor-tp6-netflix-firefox fcp linux64-shippable-qr opt 352.83 -> 362.54
3% raptor-tp6-facebook-firefox-cold fcp linux64-shippable-qr opt 365.96 -> 375.92
3% raptor-tp6-imgur-firefox linux64-shippable-qr opt 286.46 -> 294.21
3% raptor-tp6-facebook-firefox-cold linux64-shippable-qr opt 432.06 -> 443.36
3% raptor-tp6-facebook-firefox loadtime linux64-shippable-qr opt 415.44 -> 426.25
3% raptor-tp6-tumblr-firefox loadtime linux64-shippable-qr opt 638.33 -> 654.88
2% raptor-tp6-facebook-firefox-cold loadtime linux64-shippable opt 831.54 -> 851.75
2% raptor-tp6-tumblr-firefox loadtime linux64-shippable opt 614.62 -> 628.25

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23239

The backout made stuff return to normal:

== Change summary for alert #23255 (as of Fri, 27 Sep 2019 05:35:27 GMT) ==

Improvements:

7% raptor-tp6-linkedin-firefox fcp linux64-shippable opt 467.12 -> 433.38
7% raptor-tp6-linkedin-firefox fcp linux64-shippable opt 461.96 -> 431.75
6% raptor-tp6-binast-instagram-firefox linux64-shippable opt 242.80 -> 227.44
6% raptor-tp6-linkedin-firefox linux64-shippable opt 588.67 -> 552.17
6% raptor-tp6-linkedin-firefox fcp linux64-shippable-qr opt 489.88 -> 460.42
6% raptor-tp6-binast-instagram-firefox linux64-shippable-qr opt 242.12 -> 228.09
6% raptor-tp6-linkedin-firefox linux64-shippable-qr opt 621.60 -> 587.42
5% raptor-tp6-instagram-firefox linux64-shippable opt 254.82 -> 241.75
4% raptor-tp6-yahoo-mail-firefox loadtime linux64-shippable-qr opt 445.15 -> 427.96
4% raptor-tp6-google-mail-firefox loadtime linux64-shippable opt 425.88 -> 410.04
4% raptor-tp6-yahoo-mail-firefox loadtime linux64-shippable opt 424.00 -> 408.67
3% raptor-tp6-yahoo-news-firefox fcp linux64-shippable-qr opt 358.15 -> 346.21
3% raptor-tp6-netflix-firefox fcp linux64-shippable-qr opt 362.82 -> 351.67
3% raptor-tp6-netflix-firefox linux64-shippable-qr opt 439.63 -> 426.95
3% raptor-tp6-facebook-firefox-cold fcp linux64-shippable-qr opt 377.80 -> 367.00
3% raptor-tp6-imgur-firefox loadtime linux64-shippable-qr opt 407.85 -> 396.46
3% raptor-tp6-facebook-firefox-cold linux64-shippable-qr opt 444.22 -> 432.34
2% raptor-tp6-facebook-firefox-cold loadtime linux64-shippable opt 853.06 -> 832.67
2% raptor-tp6-yahoo-news-firefox linux64-shippable-qr opt 391.87 -> 382.62
2% raptor-tp6-sheets-firefox fcp linux64-shippable-qr opt 414.69 -> 405.00
2% raptor-tp6-facebook-firefox-cold loadtime linux64-shippable-qr opt 866.42 -> 847.50
2% raptor-tp6-wikipedia-firefox linux64-shippable opt 555.84 -> 544.23

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23255

https://hg.mozilla.org/mozilla-central/rev/cd1f46e85c51

== Change summary for alert #23417 (as of Thu, 10 Oct 2019 17:27:23 GMT) ==

Improvements:

7% perf_reftest_singletons id-getter-4.html windows10-64-shippable opt e10s stylo 510.08 -> 474.51
7% perf_reftest_singletons parent-basic-singleton.html windows7-32-shippable opt e10s stylo 101.19 -> 94.15
7% perf_reftest_singletons id-getter-3.html windows10-64-shippable opt e10s stylo 508.77 -> 473.65
7% perf_reftest_singletons id-getter-3.html windows10-64-shippable-qr opt e10s stylo 508.63 -> 473.62
7% perf_reftest_singletons id-getter-6.html windows10-64-shippable-qr opt e10s stylo 508.59 -> 473.84
7% perf_reftest_singletons id-getter-7.html windows10-64-shippable-qr opt e10s stylo 508.39 -> 473.72
7% perf_reftest_singletons id-getter-5.html windows10-64-shippable opt e10s stylo 508.46 -> 473.82
7% perf_reftest_singletons id-getter-7.html windows10-64-shippable opt e10s stylo 507.85 -> 473.55
7% perf_reftest_singletons id-getter-4.html windows10-64-shippable-qr opt e10s stylo 508.18 -> 473.94
7% perf_reftest_singletons id-getter-1.html windows10-64-shippable-qr opt e10s stylo 510.47 -> 476.09
7% perf_reftest_singletons id-getter-5.html windows10-64-shippable-qr opt e10s stylo 508.90 -> 475.57
6% perf_reftest_singletons id-getter-6.html windows10-64-shippable opt e10s stylo 505.12 -> 472.93
6% perf_reftest_singletons id-getter-1.html windows10-64-shippable opt e10s stylo 510.46 -> 478.78

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23417