Closed Bug 1485503 Opened Last year Closed Last year

[LTO][mac] ld64 thin-lto wrongfully merges static data with non-static data

Categories

(Firefox Build System :: General, defect)

defect
Not set

Tracking

(firefox63 fixed)

RESOLVED FIXED
mozilla63
Tracking Status
firefox63 --- fixed

People

(Reporter: glandium, Assigned: glandium)

References

Details

Attachments

(1 file)

When different translation units contain the same symbol name, all
static, but one of them non-static, ld64 wrongfully link the references
to the static data with the non-static data, or vice versa. With libaom
and libvpx sharing data structures with the same name but different
contents, that leads to interesting failures/crashes at runtime.

This was apparently fixed in Apple ld64 from Xcode 9, but the last open
sourced version is the one from Xcode 8, so I ended up digging in the
ld64 source code and fixed the issue.

This work was merged to cctools-port upstream in
https://github.com/tpoechtrager/cctools-port/pull/59.

For the same reason as invoked in bug 1478917, though, updating to
cctools-port master is more involved than just changing a commit sha1
(as it requires building apple-libtapi, which in turn builds parts of
LLVM, which should probably be avoided), so just cherry-pick the fix.
Attachment #9003305 - Flags: review?(core-build-config-reviews)
Blocks: macOS-LTO
No longer blocks: macOS-PGO
Attachment #9003305 - Flags: review?(core-build-config-reviews) → review+
Pushed by mh@glandium.org:
https://hg.mozilla.org/integration/mozilla-inbound/rev/4017bcbb799d
Avoid ld64 merging static and non-static data with the same name during ThinLTO. r=dmajor
Pushed by mh@glandium.org:
https://hg.mozilla.org/integration/mozilla-inbound/rev/4c27db2b3d66
Avoid ld64 merging static and non-static data with the same name during ThinLTO. r=dmajor
https://hg.mozilla.org/mozilla-central/rev/4c27db2b3d66
Status: NEW → RESOLVED
Closed: Last year
Resolution: --- → FIXED
Target Milestone: --- → mozilla63
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