[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

Jason Merrill  changed:

   What|Removed |Added

 Status|ASSIGNED|RESOLVED
 Resolution|--- |FIXED
   Target Milestone|--- |10.0

--- Comment #7 from Jason Merrill  ---
Fixed for GCC 10.

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

--- Comment #6 from Jason Merrill  ---
Author: jason
Date: Tue Jan  7 15:05:25 2020
New Revision: 279960

URL: https://gcc.gnu.org/viewcvs?rev=279960=gcc=rev
Log:
PR c++/47877 - -fvisibility-inlines-hidden and member templates.

DECL_VISIBILITY_SPECIFIED is also true if an enclosing scope has explicit
visibility, and we don't want that to override -fvisibility-inlines-hidden.
So check for the attribute specifically on the function, like we already do
for template argument visibility restriction.

* decl2.c (determine_visibility): -fvisibility-inlines-hidden beats
explicit class visibility for a template.

Added:
trunk/gcc/testsuite/g++.dg/ext/visibility/fvisibility-inlines-hidden-5.C
Modified:
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/decl2.c
trunk/gcc/tree.h

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

Jason Merrill  changed:

   What|Removed |Added

 Status|NEW |ASSIGNED
   Assignee|unassigned at gcc dot gnu.org  |jason at gcc dot gnu.org

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

Alexander Monakov  changed:

   What|Removed |Added

 CC||amonakov at gcc dot gnu.org

--- Comment #5 from Alexander Monakov  ---
In PR 92855 we have a similar situation where an inline template function
inherits visibility from the enclosing namespace, while a non-template function
becomes hidden as requested by -fvisibility-inlines-hidden:

namespace N
__attribute__((visibility("default")))
{
inline void foo() {};
template
inline void bar() {};
}

int main()
{
N::foo();
N::bar();
}

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

Alexander Monakov  changed:

   What|Removed |Added

 CC||thiago at kde dot org

--- Comment #4 from Alexander Monakov  ---
*** Bug 92855 has been marked as a duplicate of this bug. ***

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[jengelh at inai dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

--- Comment #3 from Jan Engelhardt  ---
Hm yes, I begin to see why this was done. Template instantiations show up as
W-type symbols in `nm`, and template specializations are 'T'-type, and both
need to be visible so that the override works.

But only on -O0.

When compiling with -O2, the template instantiations gets inlined and the
symbol (_ZN3Foo3barIS_EEvv in this example) disappears because of
-fvisibility-inlines-hidden and could not possibly be overridden. So template
specializations from elsewhere will have no effect.

...

So IMO we can probably just drop the "!processing_template_decl" part.

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

Richard Biener  changed:

   What|Removed |Added

   Keywords||documentation
 Status|UNCONFIRMED |NEW
   Last reconfirmed||2016-11-21
 CC|rguenther at suse dot de   |jason at gcc dot 
gnu.org,
   ||rguenth at gcc dot gnu.org
 Ever confirmed|0   |1

--- Comment #2 from Richard Biener  ---
Confirmed.  It looks like template instantiation somehow ends up using the
explicitely specified visibility from the class.  When
determine_visibility_from_class is called for the template
determine_hidden_inline () is false because of the processing_template_decl
check.  So the behavior is clearly on purpose and thus a documentation
issue(?):

/* Returns true iff DECL is an inline that should get hidden visibility
   because of -fvisibility-inlines-hidden.  */

static bool
determine_hidden_inline (tree decl)
{
  return (visibility_options.inlines_hidden
  /* Don't do this for inline templates; specializations might not be
 inline, and we don't want them to inherit the hidden
 visibility.  We'll set it here for all inline instantiations.  */
  && !processing_template_decl
  && TREE_CODE (decl) == FUNCTION_DECL
  && DECL_DECLARED_INLINE_P (decl)
  && (! DECL_LANG_SPECIFIC (decl)
  || ! DECL_EXPLICIT_INSTANTIATION (decl)));
}

so the reason is along non-inline specializations (not sure why we'd want to
avoid mixed visibility here).

[Bug c++/47877] -fvisibility-inlines-hidden does not hide member template functions

[jengelh at inai dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47877

Jan Engelhardt  changed:

   What|Removed |Added

 CC||jengelh at inai dot de,
   ||rguenther at suse dot de

--- Comment #1 from Jan Engelhardt  ---
The issue persists with gcc 6.2.1 and was also posted at
https://www.spinics.net/lists/gcchelp/msg46007.html with more detail.