[Bug libstdc++/21405] Template inlines have global visibility

[cristipp at excite dot com]

--- Comment #12 from cristipp at excite dot com  2006-03-20 17:07 ---
(In reply to comment #11)
> There is an one defintion rule in C++ unlike most other languages which have
> weak symbols.  And if you are working around it by using hidden symbols well
> you are asking to run into troubles.

I don't believe that C++ has to say (should say) anything that pertains to
shared libraries. Moreover, symbol versions were added as workarounds for
problems created by the ELF format semantics. This is a platform specific
problem, not a pure C++ problem. However, to have the gnu toolchain to properly
support C++ on ELF platforms, adding proper versioning for *all* symbols,
including template-originated symbols is a must. I'm not sure if this is a task
for g++ of for the linker or for both, but someone should eventually
acknowledge that there is a problem and start looking for solutions...


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21405

[Bug libstdc++/21405] Template inlines have global visibility

[cristipp at excite dot com]

--- Comment #14 from cristipp at excite dot com  2006-03-20 18:32 ---
The problem is not how the dynamic linker treats 'weak' symbols. The problem is
that template originating functions having no version numbers. It just happen
that template originating functions are also marked as weak (if I understand
correctly). In other words, if I have a regular C/C++ function, I can attach
version strings to it, whereas it I have a C++ template function I cannot
attach version strings to it, or more precisely to instances of it. I don't
really care whether symbols are 'weak' or 'strong', I only care of proper
versioning for *all* C++ symbols.

I believe that this situation was clearly described by the original bug
reporter 10 months ago. For some reason nobody seems to acknowledge that there
is a problem, the main line of reasoning so far being that 'C++ standard says
only unique (weak) names are valid'. However, that flies in the face of the
whole synmbol versioning mechanism, weak symbols or not. Afterall, versioning
for symbols was introduced precisely to allow multiple instances of the same
symbol to be valid in a shared object context.

Please feel free to correct me on any g++ internal details on which I am no
expert. However, the root problem is there and is a show-stopper for any
attempt of distributing pre-compiled C++ shared object binaries.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21405

[Bug libstdc++/21405] Template inlines have global visibility

[cristipp at excite dot com]

--- Comment #18 from cristipp at excite dot com  2006-03-22 19:10 ---
(In reply to comment #17)
> see the solution in 24660

I'm not sure I understand correctly: are all C++ template libraries supposed to
add 24660-style machinery?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21405