Re: Compiler ABI changes and XPCOM components

Jim Nance wrote:
> In article <[email protected]>, Dan Mosedale wrote:
> 
>>Even if all components survive an ABI change, both Mozilla and some of
>>the plugins link directly against libstdc++.  So right now, I've got a
>>gcc 3.1 build on my disk which can't use the flash plugin, because
>>Mozilla is linked against the gcc 3.1 version of libstdc++, and the
>>plugin is expecting the name mangling of the old version.
>>
>>That said, I think we should take a list of plugin developers and try
>>to get rough consensus that we should bite the bullet and upgrade
>>compilers, in large part because of the optimization wins we get can.
> 
> 
> Hi Dan,
>     I really think we should hold off on this.  It is going to create a
> lot of confusion to have incompatable sets of plugins floating around the
> net and thats going to generate a lot of support problems for the plugin
> authors.  And the last thing we want is for mozilla to get a "difficult to
> support" reputation. 

Well, yeah, it sucks.  But we have to do it sooner or later, and it'll 
suck whenever we do it.  And since there's a significant performance win 
involved, might as well be sooner.

>     The last I heard (and admittedly its been several months) gcc3 generated
> slower code than gcc 2.9X.  Thats expected to change, but it will take
> time and I think we should wait until there is some clear advantage to
> using gcc 3 before we push people in that direction.

Even if this were true, which I'm not sure I believe, gcc 3.1 -O2 is 
significantly faster than egcs 1.1.2 -O, which is what we're using now. 
  And it's got an ABI that is believed to be stable.

>     On a slightly related topic, will netscape 4.X plugins continue to work
> on mozilla if we switch to gcc 3?  I think several of the plugins I commonly
> use are really 4.X plugins (flash & realplayer).  I suspect most people are
> in the same boat.  Breaking these would be really bad.

That's why I suggested getting consensus among the plugin developers 
first; we would indeed need them to rebuild their plugins in order to 
pull this off.

Dan