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<!-- The actual name of your proposed change page should look something like: Changes/Your_Change_Proposal_Name. This keeps all change proposals in the same namespace --> | <!-- The actual name of your proposed change page should look something like: Changes/Your_Change_Proposal_Name. This keeps all change proposals in the same namespace --> | ||
= Stop shipping individual component libraries in clang- | = Stop shipping individual component libraries in clang-libs package <!-- The name of your change proposal --> = | ||
== Summary == | == Summary == | ||
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Note that motivation for the change should be in the Motivation section below, and this part should answer the question "What?" rather than "Why?". --> | Note that motivation for the change should be in the Motivation section below, and this part should answer the question "What?" rather than "Why?". --> | ||
Remove the individual component libraries (e.g. libclangBasic.so, libclangAST.so, etc.) from the clang- | Remove the individual component libraries (e.g. libclangBasic.so, libclangAST.so, etc.) from the clang-libs package. Packages that depend on the clang libraries should instead link against libclang-cpp.so. | ||
== Owner == | == Owner == | ||
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CLOSED as NEXTRELEASE -> change is completed and verified and will be delivered in next release under development | CLOSED as NEXTRELEASE -> change is completed and verified and will be delivered in next release under development | ||
--> | --> | ||
* Tracker bug: | * Tracker bug: [https://bugzilla.redhat.com/show_bug.cgi?id=1787375 #1787375] | ||
* Release notes tracker: | * Release notes tracker: [https://pagure.io/fedora-docs/release-notes/issue/426 #426] | ||
== Detailed Description == | == Detailed Description == | ||
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<!-- Expand on the summary, if appropriate. A couple sentences suffices to explain the goal, but the more details you can provide the better. --> | <!-- Expand on the summary, if appropriate. A couple sentences suffices to explain the goal, but the more details you can provide the better. --> | ||
The individual component libraries will be removed from the clang- | The individual component libraries will be removed from the clang-libs package in favor of libclang-cpp.so (which is already present in clang-libs). The component shared libraries enabled by the BUILD_SHARED=ON CMake option are not supported as a distribution configuration by the upstream project and only recommended for use by clang developers.[1] | ||
The libclang-cpp.so shared object was added in clang 9.0 and now gives us an alternative shared library option that is supported by the upstream project and makes it possible for Fedora packages to stop using the component libraries. | The libclang-cpp.so shared object was added in clang 9.0 and now gives us an alternative shared library option that is supported by the upstream project and makes it possible for Fedora packages to stop using the component libraries. | ||
This change will be made only in clang 10 and newer. The clang9.0 and older compatibility packages will keep the component libraries until those packages are retired. | |||
[1] https://llvm.org/docs/CMake.html | [1] https://llvm.org/docs/CMake.html | ||
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The following packages depend on clang-libs and will need to be updated: | The following packages depend on clang-libs and will need to be updated: | ||
bcc | * bcc | ||
* bpftrace | |||
* castxml | |||
* ccls | |||
* clazy | |||
* gnome-builder | |||
* ispc | |||
* kdevelop | |||
* lldb | |||
* mesa | |||
* pocl | |||
* qt-creator | |||
* qt5-doctools | |||
* shiboken2 | |||
* tinygo | |||
== Contingency Plan == | == Contingency Plan == | ||
<!-- If you cannot complete your feature by the final development freeze, what is the backup plan? This might be as simple as "Revert the shipped configuration". Or it might not (e.g. rebuilding a number of dependent packages). If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy. --> | <!-- If you cannot complete your feature by the final development freeze, what is the backup plan? This might be as simple as "Revert the shipped configuration". Or it might not (e.g. rebuilding a number of dependent packages). If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy. --> | ||
* Contingency mechanism: (What to do? Who will do it?) If we are unable to migrate all dependent packages in time, then | * Contingency mechanism: (What to do? Who will do it?) If we are unable to migrate all dependent packages in time, then the proposal owner will postpone the final step of passing -DBUILD_SHARED_LIBS=OFF to cmake when configuring clang until a future Fedora release. In this case, packages that have already been migrated will continue to work, since libclang-cpp.so is already included in the clang-libs package. | ||
<!-- When is the last time the contingency mechanism can be put in place? This will typically be the beta freeze. --> | <!-- When is the last time the contingency mechanism can be put in place? This will typically be the beta freeze. --> | ||
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--> | --> | ||
The individual component libraries (e.g. libclangBasic.so, libclangAST.so, etc.) have been removed from the clang-libs packages. Developers who want to link their application against the clang libraries should link against libclang-cpp.so instead. | |||
[[Category: | [[Category:ChangeAcceptedF32]] | ||
<!-- When your change proposal page is completed and ready for review and announcement --> | <!-- When your change proposal page is completed and ready for review and announcement --> | ||
<!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler --> | <!-- remove Category:ChangePageIncomplete and change it to Category:ChangeReadyForWrangler --> | ||
Latest revision as of 15:49, 2 January 2020
Stop shipping individual component libraries in clang-libs package
Summary
Remove the individual component libraries (e.g. libclangBasic.so, libclangAST.so, etc.) from the clang-libs package. Packages that depend on the clang libraries should instead link against libclang-cpp.so.
Owner
- Name: Tom Stellard
- Email: <tstellar@redhat.com>
Current status
- Targeted release: Fedora 32
- Last updated: 2020-01-02
- Tracker bug: #1787375
- Release notes tracker: #426
Detailed Description
The individual component libraries will be removed from the clang-libs package in favor of libclang-cpp.so (which is already present in clang-libs). The component shared libraries enabled by the BUILD_SHARED=ON CMake option are not supported as a distribution configuration by the upstream project and only recommended for use by clang developers.[1]
The libclang-cpp.so shared object was added in clang 9.0 and now gives us an alternative shared library option that is supported by the upstream project and makes it possible for Fedora packages to stop using the component libraries.
This change will be made only in clang 10 and newer. The clang9.0 and older compatibility packages will keep the component libraries until those packages are retired.
[1] https://llvm.org/docs/CMake.html
Benefit to Fedora
We will improve stability in Fedora by packaging a build configuration that is supported by the upstream project. In addition, libclang-cpp.so will provide more LTO optimization opportunities than the component libraries if LTO is enabled in Fedora builds. Also, in order to access the clang API with the component libraries, an application might need to link with up to 37 different shared libraries, replacing these with a single shared library will help improve application start-up times.
Scope
- Proposal owners:
- The proposal owner will ensure that that all packages that depend on clang-libs are updated to use libclang-cpp.so.
- Once all dependent packages have been migrated, the clang package will be updated to pass -DBUILD_SHARED=OFF to cmake when configuring.
- Other developers: The other maintainers will be responsible for reviewing and approving changes to their packages.
- Release engineering: [1] (a check of an impact with Release Engineering is needed)
- Policies and guidelines: No policies or guidelines will need to be updated as a result of this change.
- Trademark approval: N/A (not needed for this Change)
Upgrade/compatibility impact
This change should not impact upgradeability.
How To Test
This can be tested using existing CI tests or tests in the %check section of spec files. The changes should not be visible to end users so tests should behave exactly as they did before the change.
User Experience
End users that develop applications using the clang libraries will need to update their applications to use libclang-cpp.so instead of the individual component libraries if they want to use libraries shipped with Fedora. This may be inconvenient, but we don't want users to continue using a configuration that is not supported by the upstream project. Once this change is made though, the applications will see the same benefits mentioned in the "Benefits to Fedora" section.
End users using Fedora packages that depend on clang libraries will not need to do anything different.
Dependencies
The following packages depend on clang-libs and will need to be updated:
- bcc
- bpftrace
- castxml
- ccls
- clazy
- gnome-builder
- ispc
- kdevelop
- lldb
- mesa
- pocl
- qt-creator
- qt5-doctools
- shiboken2
- tinygo
Contingency Plan
- Contingency mechanism: (What to do? Who will do it?) If we are unable to migrate all dependent packages in time, then the proposal owner will postpone the final step of passing -DBUILD_SHARED_LIBS=OFF to cmake when configuring clang until a future Fedora release. In this case, packages that have already been migrated will continue to work, since libclang-cpp.so is already included in the clang-libs package.
- Contingency deadline: Change Checkpoint: Completion deadline
- Blocks release? No
- Blocks product? None
Documentation
Release notes will be added for this change.
Release Notes
The individual component libraries (e.g. libclangBasic.so, libclangAST.so, etc.) have been removed from the clang-libs packages. Developers who want to link their application against the clang libraries should link against libclang-cpp.so instead.