gcc visibility used by moz

[Benjamin Smedberg]

Jason Merrill wrote:

> OK, you've convinced me that the compiler shouldn't override or complain 
> about explicit visibility attributes.  Do you have a problem with 
> implicit propagation of visibility in the absence of an attribute? 
> Specifically:
> 
> Do you agree with implicitly giving template instantiations the minimum 
> visibility of the template and arguments unless explicitly overridden?

Thinking about this further and reading the discussion that's flowed around, 
I tend to want to change my opinion to say that argument types should not 
affect the visibility of a symbol at all. It breaks compatibility with 
existing usage in gcc 4.0/4.1, as well as being a non-obvious change 
(especially for pointer types, which, absent questions of dynamic casting 
and RTTI can safely be passed across DSO boundaries). At least in the case 
of Mozilla, RTTI is a non-issue.

Perhaps the compiler should issue a warning in such cases that RTTI may not 
work correctly.

--BDS