1243647 - Fix -Wimplicit-fallthrough warnings by breaking at unintentional switch fallthroughs in AsmJS.cpp

Status: RESOLVED FIXED

(Core :: JavaScript Engine: JIT, defect)

Description

[Chris Peterson [:cpeterson]]

Attachment: AsmJS_MOZ_FALLTHROUGH.patch

clang's -Wimplicit-fallthrough warnings (not yet enabled in mozilla-central) warn about switch cases that fall through without a break or return statement.

MOZ_FALLTHROUGH (bug 1215411) is an annotation to suppress -Wimplicit-fallthrough warnings where the fallthrough is intentional, but in this case, the switch fallthroughs after each ENUMERATE() look unintentional. Is that correct?

js/src/asmjs/AsmJS.cpp:2598:7: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
js/src/asmjs/AsmJS.cpp:2601:7: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
js/src/asmjs/AsmJS.cpp:2604:7: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]

Comment 1

[Benjamin Bouvier [:bbouvier] (inactive)]

Comment on attachment 8713035 [details] [diff] [review]
AsmJS_MOZ_FALLTHROUGH.patch

Review of attachment 8713035 [details] [diff] [review]:
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Good catch, this couldn't happen in practice because there's another switch preventing we ever fall in these impossible cases, but better to make it explicit.

Comment 2

[Benjamin Bouvier [:bbouvier] (inactive)]

I've seen this in a Coverity report received yesterday. Marking checkin-needed to move things forward.

Comment 3

[Chris Peterson [:cpeterson]]

Thanks. I had just been too lazy to get around to landing this lone patch. :)

Comment 4

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/fae687abfc46

Comment 5

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/fae687abfc46