Re: [C++ PATCH] Fix PR6749 (infinite loop generating vtable)

[Mark Mitchell <mark at codesourcery dot com>]

Kriang Lerdsuwanakij wrote:

> Hi
>
> This patch fixes an infinite loop: generating a vtable may trigger
> template instantiation of function template which is virtual.  This
> in turn can cause another vtable to be generated.  And this could
> continue forever.  With the patch, the option -ftemplate-depth
> to limit the number of such attempts.
>
> Since the function 'instantiate_pending_templates', modified by this
> patch, is only used by 'finish_file' and its return type is never used.
> I simplify this as well.
>
> Tested on i686-pc-linux-gnu with no regressions.  OK for mainline?
OK.

Though, in the specific case of vtables, I suspect we might win bigger 
if we made vtable creation lazy.  Right now, we may be computing a lot 
of stuff when the closing "}" of a class is encoutered that we probably 
do not need to do until someone really tries to use the class.  Of 
course, if there always tend to be non-trivial uses of the class, then 
the current approach wins.

--
Mark Mitchell
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mark@codesourcery.com