Missing symbols when built with Clang -fvisibility=hidden

[JamiKettunen]

Building libglibutil 1.0.74 with LTO and -fvisibility=hidden (pre-requisite of CFI which I filed another issue about already and skipped all broken tests for the moment) I see libgbinder 1.1.35 failing to build due to various undefined symbols from libglibutil which were not marked as part of public API with a __attribute__((visibility("default"))) macro or similar:

ld: error: undefined symbol: gutil_log
>>> referenced by test_binder.c:367 (./unit/unit_bridge/../common/test_binder.c:367)
>>>               lto.tmp:(test_binder_node_unref.llvm.18437551932447681344)
>>> referenced by test_binder.c:336 (./unit/unit_bridge/../common/test_binder.c:336)
>>>               lto.tmp:(test_binder_node_unref.llvm.18437551932447681344)
>>> referenced by gbinder_client.c:210 (./src/gbinder_client.c:210)
>>>               lto.tmp:(gbinder_client_transact_sync_reply2)
>>> referenced 251 more times

Which for example this could be a naïve fix to:

--- a/include/gutil_log.h
+++ b/include/gutil_log.h
@@ -125,6 +125,7 @@ gutil_log_description(
     int count);                     /* Number of known modules */
 
 /* Logging function */
+__attribute__((visibility("default")))
 void
 gutil_log(
     const GLogModule* module,       /* Calling module (NULL for default) */

A bunch more can be seen in the full build log: https://paste.c-net.org/x0nhhzxganl3

https://clang.llvm.org/docs/LTOVisibility.html and https://gcc.gnu.org/wiki/Visibility could be of interest

[monich]

I wonder if a linker script would help to remedy that and at the same time keep public headers clean 🤔

[monich]

No, the version script doesn't seem to override the visibility 😐

[monich]

PR #10 should take care of that.

[JamiKettunen]

Seems to work for my purposes now; as I mentioned on the other issue same could now be done for libgbinder