Bug 15554

Summary:	reproducibility failures with 'rustdoc' on rust 1.75
Product:	[Build System, Metadata & Runtime] OE-Core	Reporter:	Sundeep Kokkonda <sundeep.kokkonda>
Component:	devtools / tool chain	Assignee:	Sundeep Kokkonda <sundeep.kokkonda>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	High	CC:	meta.mr.watcher, meta.watcher, randy.macleod, richard.purdie
Version:	unspecified
Target Milestone:	5.1 M3
Hardware:	x86
OS:	Multiple
Whiteboard:	backport 5.0
OS type for building Yocto:	---	Type of Regression:	---
Verified:		Documentation change:	No (bug/feature does not impact docs)

Description Sundeep Kokkonda 2024-07-18 09:02:15 UTC

The 'rustdoc' binary is not reproducible. Issue seen on rust 1.75.
More details:
https://lists.openembedded.org/g/openembedded-core/message/200077

Comment 1 Sundeep Kokkonda 2024-07-18 09:03:58 UTC

The issue is reproduced only when the path length of build directories are differed.
https://lists.openembedded.org/g/openembedded-core/message/201616

Comment 2 Sundeep Kokkonda 2024-07-18 09:07:08 UTC

This issue is reproducible on rust upstream sources and reported the bug to upstream.
https://github.com/rust-lang/rust/issues/126976

- The dump of librustdoc-xxxx.rlib's shows that the *.rcgu.o are with different sizes. I tried the builds by disabling the rcgu's with codegen-units = 1. But still the compiled rustdoc with single rcgu also differed.

- The increase of codegen-units = 256 or lto = off or opt-level = 0 also doesn't solve the problem.

Further analysis is on-going and upstream doesn't have any clue about the root cause of the issue.

Comment 3 Richard Purdie 2024-08-01 14:46:14 UTC

https://git.yoctoproject.org/poky/commit/?id=e2e7017350d0b5324811fef3b841f98b00273887

Great to have this fixed, thanks Sundeep!