1409680 - Conditionally disable Rust debug symbols

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Description

[Jan Beich]

To keep memory usage low on 32bit hosts it maybe nice to provide a way to disable -C debuginfo=2.

Comment 1

[Jan Beich]

Attachment: Bug 1409680 - Extend --disable-debug-symbols to Rust code.

This reduces disk I/O and memory usage during build that already lacks
debugging symbols from C++ code, allowing to use more jobs on 32bit hosts.

--disable-debug-symbols build on FreeBSD 10.3 i386 (8 cores) host:
Max RSS before:  libxul - 612 Mb, libgkrust - 1908 Mb
Max RSS after:   libxul - 444 Mb, libgkrust - 1471 Mb
Binary before:   libxul - 203 Mb, libgkrust -  732 Mb
Binary after:    libxul - 123 Mb, libgkrust -  301 Mb

Review commit: https://reviewboard.mozilla.org/r/190588/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/190588/

Comment 2

[Jan Beich]

Downstream FreeBSD keeps non-debug symbols for profiling (dtrace, pmcstat) and quick stacktraces. Since Rust dependency was introduced libxul.so grew in size for no good reason (Firefox is mostly C++). And Stylo will bump the size even more.

Such use case is probably less common than simply stripping the binary.

Comment 3

[Landry Breuil (:gaston)]

Comment on attachment 8919676 [details]
Bug 1409680 - Extend --disable-debug-symbols to Rust code.

Allows me to build m-c with stylo and webrender on OpenBSD/i386, using --disable-debug-symbols.

Comment 4

[Mike Hommey [:glandium]]

Comment on attachment 8919676 [details]
Bug 1409680 - Extend --disable-debug-symbols to Rust code.

https://reviewboard.mozilla.org/r/190588/#review196206

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/19a66220f57c
Extend --disable-debug-symbols to Rust code. r=glandium

Comment 6

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/19a66220f57c

Comment 7

[Jan Beich]

Attachment: rebased for Firefox 57

Approval Request Comment
[Feature/Bug causing the regression]: bug 1283898 but bug 1342450 and bug 1356991 made it worse
[User impact if declined]: --disable-debug-symbols builds on 32bit hosts may run out of memory and fail (see bug 1401093). The resulting package wastes ~70Mb of space for incomplete debug symbols (i.e., Rust but not C++) unless stripped.
[Is this code covered by automated tests?]: AFAIK, --disable-debug-symbols isn't used by automation at all.
[Has the fix been verified in Nightly?]: Yes, also on FF57 downstream. Automation build logs contain -C debuginfo=2 as before.
[Needs manual test from QE? If yes, steps to reproduce]: No.
[List of other uplifts needed for the feature/fix]: None
[Is the change risky?]: No
[Why is the change risky/not risky?]: Can either break build or unintentionally disable Rust debug symbols (e.g., used to show source lines in stacktraces).
[String changes made/needed]: None

Comment 8

[Jan Beich]

Comment on attachment 8920531 [details] [diff] [review]
rebased for Firefox 57

https://treeherder.mozilla.org/#/jobs?repo=try&revision=ddfe1d34783c

Comment 9

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

Comment on attachment 8920531 [details] [diff] [review]
rebased for Firefox 57

makes sense, Beta57+

Comment 10

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/92ec0c204c77