Re: [whopr] Design/implementation alternatives for the driver and WPA

[Chris Lattner <clattner at apple dot com>]

On Jun 5, 2008, at 2:03 PM, Ian Lance Taylor wrote:

> Nick Kledzik <kledzik@apple.com> writes:
>
> > > How does the linker tell LTO that a symbol may be inlined, but must
> > > also be externally visible?
> > The linker just tells LTO which symbols must remain.  The LTO engine
> > is free to inline anything that would improve codegen, with the
> > exception
> > that any weak definition that must remain (preserved) cannot be  
> > inlined.
>
> I'll just note that that isn't optimal for ELF when producing an
> executable.

Why? Because you have to touch (worst case) every symbol?  The cost of  
doing LTO *dramatically* dwarfs the cost of touching symbols  
once.  :)  You're right this could be improved, and we're actively  
working on it... but it seems like a strange thing to worry about vs  
correctness in all cases.

-Chris