Closed Bug 1593703 Opened 4 years ago Closed 4 years ago

MOZ_IMPLICIT seems to be busted with clang 5


(Developer Infrastructure :: Source Code Analysis, defect, P1)



(firefox72 fixed)

Tracking Status
firefox72 --- fixed


(Reporter: froydnj, Assigned: andi)




(1 file)

See e.g.

where we are bumping the minimum clang version to 5: the base toolchains build for clang (which uses clang 5 in this case), complains about CheckedInt constructors not being marked as explicit when they are in fact marked as MOZ_EXPLICIT.

Andi, can you take a look at this?

Flags: needinfo?(bpostelnicu)

P1 as blocking some compiler upgrade.

Priority: -- → P1
Assignee: nobody → bpostelnicu
Flags: needinfo?(bpostelnicu)

Since this is a P1, I'm working on this, will come up with an update shortly.

Clang 5 has a serious problem when it generates the AnnotateAttr for a Decl it only supports a single annotation and the rest are dropped. In the case for CheckedInt we have present two annotations MOZ_IMPLICIT and MOZ_NO_ARITHMETIC_EXPR_IN_ARGUMENT but only the later one is included into the AST node.
Let's take as an example js/src/builtin/RegExp.cpp we have 8 AST matches for CheckedInt(U) but only for the later one we have generated the sane specific_attrs. Also this behavior ranges from clang 5.0 - clang 6.0 and was fixed in 7.0.
So this leads me to the concussion that right now we are dealing with a corrupt AST for a compilation unit, at least the one that is exposed to clang-tooling.

Attachment #9106930 - Attachment description: Bug 1593703 - for some unsupported toolchains (clang 5, clang 6) disable clang based static-analysis. → Bug 1593703 - disable clang based static-analysis for build-linux64-base-toolchains-clang/*.
See Also: → 1594473
Pushed by
disable clang based static-analysis for build-linux64-base-toolchains-clang/*. r=froydnj
Closed: 4 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla72

== Change summary for alert #23731 (as of Wed, 06 Nov 2019 22:09:41 GMT) ==


11% build times linux64 debug base-toolchains-clang taskcluster-m5.4xlarge 2,016.28 -> 1,795.81
9% build times linux64 opt base-toolchains-clang taskcluster-c5d.4xlarge 1,789.33 -> 1,625.03
8% build times linux64 opt base-toolchains-clang taskcluster-m5.4xlarge 1,949.11 -> 1,795.07

For up to date results, see:

Product: Firefox Build System → Developer Infrastructure
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