swiftlang/swift-package-manager

dsymutil emits warnings with experimental lto mode

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#6,890 opened on Sep 12, 2023

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bughelp wanted

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Description

When using --experimental-lto-mode=full dsymutil complains about not being able to find (intermediate?) object files created during the LTO process. Example:

$ git clone git@github.com:apple/swift-nio.git
$ cd swift-nio
$ swift build --configuration release --experimental-lto-mode=full --verbose
warning: (arm64) /tmp/lto.o unable to open object file: No such file or directory
warning: (arm64)  could not find object file symbol for symbol _$sSo14_sa_DoubleWordaMa
warning: (arm64)  could not find object file symbol for symbol _$sSo14_sa_DoubleWordaMaTm
...

Contributor guide

Research direction
Investigate how dsymutil handles LTO object files and trace the build process to ensure intermediate LTO objects are accessible during debug symbol generation.
Tech stack
swift
Domain
backendbuild system
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
SwiftLTO
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50