Experiment: Reduce the ABI surface on Linux with '-fvisibility-inlines-hidden' by Vika-F · Pull Request #3604 · uxlfoundation/oneDAL

Vika-F · 2026-04-10T12:25:41Z

Description

Implements a better solution to the problem of the ABI fragility caused by the inline methods, including destructors.

See the problem description in the PR #3591; also read this blog post for better understanding of the problem and the solution:
https://holyblackcat.github.io/blog/2025/12/01/visibility-inlines-hidden.html

abicheck tool summary:

ABI Report: libonedal_core.so


Verdict	⚠️ `COMPATIBLE_WITH_RISK`
Breaking changes	0
Source-level breaks	0
Deployment risk changes	2
Compatible changes	2137

⚠️ Deployment Risk Changes

These changes are binary-compatible but may cause the library to fail
loading on older systems (e.g. a new GLIBC version requirement). Verify
your target environment before deploying.

symbol_leaked_from_dependency_changed: Symbol 'std::vector<std::__cxx11::basic_string<char, std::char_traits, std::allocator >, std::allocator<std::__cxx11::basic_string<char, std::char_traits, std::allocator > > >::push_back(std::__cxx11::basic_string<char, std::char_traits, std::allocator >&&)' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
symbol_leaked_from_dependency_changed: Symbol 'std::vector<std::__cxx11::basic_string<char, std::char_traits, std::allocator >, std::allocator<std::__cxx11::basic_string<char, std::char_traits, std::allocator > > >::~vector()' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.

ABI Report: libonedal.so


Verdict	⚠️ `COMPATIBLE_WITH_RISK`
Breaking changes	0
Source-level breaks	0
Deployment risk changes	51
Compatible changes	353

⚠️ Deployment Risk Changes

These changes are binary-compatible but may cause the library to fail
loading on older systems (e.g. a new GLIBC version requirement). Verify
your target environment before deploying.

symbol_leaked_from_dependency_changed: Symbol 'std::__detail::__variant::_Variant_storage<false, std::shared_ptr, std::shared_ptr >::_M_reset()' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
symbol_leaked_from_dependency_changed: Symbol 'std::map<unsigned long, std::__cxx11::basic_string<char, std::char_traits, std::allocator > const, std::less, std::allocator<std::pair<unsigned long const, std::__cxx11::basic_string<char, std::char_traits, std::allocator > const> > >::~map()' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
symbol_leaked_from_dependency_changed: Symbol 'std::enable_if<((__exactly_once<std::_Nth_type<__accepted_index<std::shared_ptr&&>, std::shared_ptr, std::shared_ptr >::type>)&&(is_constructible_v<std::_Nth_type<__accepted_index<std::shared_ptr&&>, std::shared_ptr, std::shared_ptr >::type, std::shared_ptr >))&&(is_assignable_v<std::_Nth_type<__accepted_index<std::shared_ptr&&>, std::shared_ptr, std::shared_ptr >::type&, std::shared_ptr >), std::variant<std::shared_ptr, std::shared_ptr >&>::type std::variant<std::shared_ptr, std::shared_ptr >::operator=<std::shared_ptr >(std::shared_ptr&&)' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
...

ABI Report: libonedal_dpc.so


Verdict	⚠️ `COMPATIBLE_WITH_RISK`
Breaking changes	0
Source-level breaks	0
Deployment risk changes	115
Compatible changes	452

⚠️ Deployment Risk Changes

These changes are binary-compatible but may cause the library to fail
loading on older systems (e.g. a new GLIBC version requirement). Verify
your target environment before deploying.

symbol_leaked_from_dependency_changed: Symbol 'std::__detail::__variant::_Variant_storage<false, std::shared_ptr, std::shared_ptr >::~_Variant_storage()' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
symbol_leaked_from_dependency_changed: Symbol 'std::__detail::__variant::_Variant_storage<false, std::shared_ptr, std::shared_ptr >::_M_reset()' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
symbol_leaked_from_dependency_changed: Symbol 'std::__detail::__variant::_Variant_storage<false, std::shared_ptr, std::shared_ptr >::_M_reset()' was removed but appears to originate from 'libstdc++.so.6' (a dependency of this library). This is a real ABI change — the library is leaking dependency symbols into its public ABI surface. Consider applying -fvisibility=hidden.
...

ABI Report: libonedal_parameters.so


Verdict	⚠️ `COMPATIBLE_WITH_RISK`
Breaking changes	0
Source-level breaks	0
Deployment risk changes	10
Compatible changes	23

ABI Report: libonedal_parameters_dpc.so


Verdict	⚠️ `COMPATIBLE_WITH_RISK`
Breaking changes	0
Source-level breaks	0
Deployment risk changes	10
Compatible changes	28

ABI Report: libonedal_thread.so


Verdict	✅ `COMPATIBLE`
Breaking changes	0
Source-level breaks	0
Deployment risk changes	0
Compatible changes	1

Checklist:

Completeness and readability

I have commented my code, particularly in hard-to-understand areas.
The changes are small and self-descriptive.
Git commit message contains an appropriate signed-off-by string (see CONTRIBUTING.md for details).
I have resolved any merge conflicts that might occur with the base branch.

Testing

I have run it locally and tested the changes extensively.
All CI jobs are green or I have provided justification why they aren't.
I have extended testing suite if new functionality was introduced in this PR.

No new functionality was introduced, though the ABI testing mechanism should be improved, but not in this PR.

Performance

Not applicable.

david-cortes-intel · 2026-04-10T12:29:55Z

@Vika-F What about MSVC?

david-cortes-intel · 2026-04-10T12:34:01Z

@Vika-F What about MSVC?

Took a look at the article, not required on msvc.

Vika-F · 2026-04-10T13:56:41Z

@Vika-F What about MSVC?

Took a look at the article, not required on msvc.

@david-cortes-intel thanks for early review. The only issue is that abidiff will consider this PR an ABI-breaking as it removes a lot of inlines from the ABI, but this can lead to a real ABI breakage in rare cases.
So, we need to re-consider the ABI checking mechanism.

david-cortes-intel

LGTM, but deferring to @Alexandr-Solovev about ABI part.

Vika-F · 2026-04-13T08:23:20Z

/intelci: run

Copilot

Pull request overview

This PR experiments with reducing the exported ABI surface by compiling with -fvisibility-inlines-hidden (alongside -fvisibility=hidden), aiming to make inline methods/destructors less ABI-fragile in the produced shared libraries.

Changes:

Add -fvisibility-inlines-hidden to the Make-based build visibility flags.
Add -fvisibility-inlines-hidden to Bazel copts for both DAL and DAAL modules (non-Windows builds).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
`makefile`	Extends the non-Windows visibility flags to include `-fvisibility-inlines-hidden`.
`dev/bazel/dal.bzl`	Adds `-fvisibility-inlines-hidden` to default (non-Windows) Bazel C++ compile options for DAL modules.
`dev/bazel/daal.bzl`	Adds `-fvisibility-inlines-hidden` to default (non-Windows) Bazel C++ compile options for DAAL modules.

Copilot · 2026-04-14T08:57:25Z

        copts = copts + select({
            "@platforms//os:windows": [],
-            "//conditions:default": ["-fvisibility=hidden"],
+            "//conditions:default": ["-fvisibility=hidden", "-fvisibility-inlines-hidden"],
        }),


Same as in dev/bazel/dal.bzl: //conditions:default enables -fvisibility-inlines-hidden on all non-Windows OSes, not just Linux. If the experiment is Linux-only, please scope this flag to @platforms//os:linux to avoid unintended ABI/symbol-visibility changes on macOS.

Copilot · 2026-04-14T08:57:26Z

 -optlevel      := $(-optlevel.$(COMPILER))
 -fPIC          := $(if $(OS_is_win),,-fPIC)
-visibility    := $(if $(OS_is_win),,-fvisibility=hidden)
+-visibility    := $(if $(OS_is_win),,-fvisibility=hidden -fvisibility-inlines-hidden)


The PR title/description says this experiment is for Linux, but this Makefile flag is enabled for all non-Windows platforms (including macOS). If the intent is Linux-only (ELF ABI surface reduction), gate -fvisibility-inlines-hidden behind OS_is_lnx (or equivalent) so macOS builds/ABI aren’t affected unintentionally.

Copilot · 2026-04-14T08:57:26Z

            "@platforms//os:windows": [],
-            "//conditions:default": ["-fvisibility=hidden"],
+            "//conditions:default": ["-fvisibility=hidden", "-fvisibility-inlines-hidden"],
        }),


This applies -fvisibility-inlines-hidden to every non-Windows Bazel build via //conditions:default, which includes macOS as well. If this PR is meant to be Linux-only (per title), please restrict the flag to @platforms//os:linux (and leave other OSes unchanged) to avoid changing symbol visibility/ABI on macOS unexpectedly.

Reduce ABI surface with '-fvisibility-inlines-hidden' option

913027a

Vika-F added the enhancement label Apr 10, 2026

Vika-F changed the title ~~Experiment: Reduce ABI surface with '-fvisibility-inlines-hidden'~~ Experiment: Reduce the ABI surface on Linux with '-fvisibility-inlines-hidden' Apr 10, 2026

david-cortes-intel approved these changes Apr 10, 2026

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Alexandr-Solovev approved these changes Apr 14, 2026

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Vika-F marked this pull request as ready for review April 14, 2026 08:54

Copilot AI review requested due to automatic review settings April 14, 2026 08:54

Copilot started reviewing on behalf of Vika-F April 14, 2026 08:55 View session

Copilot AI reviewed Apr 14, 2026

View reviewed changes

Vika-F merged commit 867c643 into uxlfoundation:main Apr 15, 2026
37 of 42 checks passed

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Experiment: Reduce the ABI surface on Linux with '-fvisibility-inlines-hidden'#3604

Experiment: Reduce the ABI surface on Linux with '-fvisibility-inlines-hidden'#3604
Vika-F merged 1 commit intouxlfoundation:mainfrom
Vika-F:dev/abi_inlines_hidden

Vika-F commented Apr 10, 2026 •

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Vika-F commented Apr 10, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description

abicheck tool summary:

ABI Report: libonedal_core.so

⚠️ Deployment Risk Changes

ABI Report: libonedal.so

⚠️ Deployment Risk Changes

ABI Report: libonedal_dpc.so

⚠️ Deployment Risk Changes

ABI Report: libonedal_parameters.so

ABI Report: libonedal_parameters_dpc.so

ABI Report: libonedal_thread.so

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Pull request overview

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Vika-F commented Apr 10, 2026 •

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