https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106023
Bug ID: 106023
Summary: Would like to control the ELF visibility of template
explicit instantiations
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: thiago at kde dot org
Target Milestone: ---
Given a template like:
template <typename T> struct __attribute__((visibility("hidden"))) S
{
static constexpr int n = 0;
};
I would like to mark an explicit instantiation (not a specialisation!) with a
different visibility:
template struct __attribute__((visibility("default"))) S<int>;
template __attribute__((visibility("default"))) const int S<unsigned>::n;
Either solution would help me, but the first would be preferable. Both would be
best.
Clang does support both forms properly. Visual Studio supports the former only.
See https://gcc.godbolt.org/z/T7sdzTnbG and note how GCC adds ".hidden" to the
two "::n" symbols and Clang doesn't, while Clang properly refers to those
symbols using @GOTPCREL and GCC doesn't. The MVSC example uses dllimport only
to highlight the difference; it wouldn't be written like this in real code.
Please ensure "protected" visibility also works. See
https://gcc.godbolt.org/z/o3W4x5YsG
