cmake: Emulate Libtool's behavior on NetBSD and OpenBSD #1860

pull hebasto wants to merge 4 commits into bitcoin-core:master from hebasto:260601-libtool-abi changing 2 files +66 −28

hebasto commented at 8:56 PM on June 1, 2026: member

This is a continuation of #1685.

Additionally, the logic has been factored out into its own module and the documentation has been also improved.
real-or-random added the label build on Jun 2, 2026
real-or-random added the label tweak/refactor on Jun 2, 2026
hebasto commented at 7:15 PM on June 6, 2026: member

Here are GHA jobs that show ABI versioning: https://github.com/hebasto/secp256k1/actions/runs/27071316706.

Undrafted.
hebasto marked this as ready for review on Jun 6, 2026
real-or-random commented at 9:26 AM on June 9, 2026: contributor

Concept ACK
hebasto commented at 10:58 AM on June 9, 2026: member

@theStack

Fancy checking the OpenBSD part?

in cmake/LibtoolCompatibleABI.cmake:3 in 8b6087f62e

   0 | @@ -0,0 +1,28 @@
   1 | +# This emulates Libtool to make sure Libtool and CMake agree on the ABI version,
   2 | +# see below "Calculate the version variables" in autotools-aux/ltmain.sh.
   3 | +function(secp256k1_set_libtool_abi_version target current revision age)

real-or-random commented at 11:02 AM on June 9, 2026:

naming: All other custom functions in cmake/ don't have the secp256k1_ prefix and the filename matches the function name.

hebasto commented at 12:28 PM on June 9, 2026:

Thanks! Updated.

real-or-random requested review from Copilot on Jun 9, 2026
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copilot_work_started real-or-random

Copilot commented at 11:06 AM on June 9, 2026: none

Pull request overview

This PR refactors CMake-side shared library ABI/version handling into a dedicated module and extends the Libtool-compatibility logic to cover NetBSD and OpenBSD, continuing the work from #1685 to keep Autotools/Libtool and CMake installs consistent.

Changes:

Factor Libtool-compatible ABI version property logic into a new cmake/LibtoolCompatibleABI.cmake module.
Update the secp256k1 target to use the new helper function rather than inline platform conditionals.
Add NetBSD/OpenBSD-specific versioning behavior intended to match Libtool’s platform rules.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
`src/CMakeLists.txt`	Replaces inline ABI/version property logic with a call into the new Libtool-compatibility module.
`cmake/LibtoolCompatibleABI.cmake`	New helper implementing per-OS ABI/version property rules (Linux/FreeBSD/NetBSD/OpenBSD/macOS/Windows).

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cmake, refactor: Introduce `SetLibtoolAbiVersion` module acf2084aa7
cmake, refactor: Improve documenting in `SetLibtoolAbiVersion` module 8a0f4002c7
cmake: Fix shared library versioning on NetBSD a401c5145a
cmake: Fix shared library versioning on OpenBSD 1eab757207
in cmake/SetLibtoolAbiVersion.cmake:36 in 13a403c6a9 outdated
```
  31 | +  elseif(APPLE)
  32 | +    math(EXPR _compatibility "${current} + 1")
  33 | +    set_target_properties(${target} PROPERTIES
  34 | +      MACHO_COMPATIBILITY_VERSION ${_compatibility}
  35 | +      MACHO_CURRENT_VERSION ${_compatibility}.${revision}
  36 | +    )
```
Copilot commented at 11:06 AM on June 9, 2026:

On Apple, the previous logic always set SOVERSION (computed from current - age) before applying Mach-O version properties. In the new helper function the Apple branch sets only MACHO_* properties, so SOVERSION is no longer set, which can change the installed dylib name/symlink layout and break the goal of keeping Libtool and CMake ABI versioning aligned.

real-or-random commented at 11:59 AM on June 9, 2026:

Hm, the LLM has a point:

For shared libraries, the MACHO_COMPATIBILITY_VERSION and MACHO_CURRENT_VERSION properties can be used to override the compatibility version and current version respectively. Note that SOVERSION will still be used to form the install_name and both SOVERSION and VERSION may also affect the file and symlink names.

https://cmake.org/cmake/help/latest/prop_tgt/SOVERSION.html

hebasto commented at 12:27 PM on June 9, 2026:

Hm, the LLM has a point:

Indeed. Fixed.
in cmake/LibtoolCompatibleABI.cmake:4 in 13a403c6a9
```
   0 | @@ -0,0 +1,51 @@
   1 | +# This emulates Libtool to make sure Libtool and CMake agree on the ABI version.
   2 | +# The `version_type` variable is set in autotools-aux/m4/libtool.m4.
   3 | +# For the `major` and `versuffix` variables, see below "Calculate the version
   4 | +# variables" in autotools-aux/ltmain.sh.
```
Copilot commented at 11:06 AM on June 9, 2026:

The header comment points readers to autotools-aux/m4/libtool.m4 and autotools-aux/ltmain.sh, but those files are not present in the repository checkout (they are typically generated/installed by autoreconf). Consider clarifying that these files are produced by the Autotools bootstrap step so the references are actionable for someone reading the source tree.

hebasto commented at 12:28 PM on June 9, 2026:

Taken.
hebasto force-pushed on Jun 9, 2026
hebasto commented at 12:27 PM on June 9, 2026: member

The recent feedback has been addressed.

Here are GHA jobs that show ABI versioning on OpenBSD, NetBSD and macOS: https://github.com/hebasto/secp256k1/actions/runs/27205923502.

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#1685 cmake: Emulate Libtool's behavior on FreeBSD