Re: Some questions on Solaris linker

From: Christopher Currie (Christopher_at_[hidden])
Date: 2004-01-08 15:33:59

Vladimir Prus wrote:
> I'd very appreciate if someone can answer two questions above. I looks like 
> some persons on this list has used V2 + gcc + solaris linker, so they might 
> know the answers right away.

This is the configuration I'm using for gcc, so I'll take a stab...

> 1. The docs on Sun site say:
> 
> Although the link-editor makes multiple passes through an archive to resolve 
> symbols, this mechanism can be quite costly for large archives containing 
> random organizations of relocatable objects. In these cases you can use tools 
> like lorder(1) and tsort(1) to order the relocatable objects within the 
> archive and so reduce the number of passes the link-editor must carry out. 
> 
> Is this really the case? Was this behaviour introduced long enough for us to 
> assume it exists for all version of Solaris linkers now in use?

These tools do exist; I'd not heard of them before, so I can't attest as 
to the effect that they'll have on link times. The typical usage they 
recommend is something like:

ar -rc lib.a `lorder *.o | tsort`

which purports to find the optimum sorting order *within the context of 
a single library* so it doesn't have to read itself multiple times to 
resolve its own references. (i.e. this technique is not for inter-lib 
dependencies). All it really does is reorder the library list for 
efficiency, so I assume the technique would be equally useful for shared 
libraries. I can make this change locally and run some time tests 
building and linking against boost libraries, if feel it's necessary.

> 2. Does the Solaris linker has an equivalent of GNU's --rpath-link option? 
> Just in case you don't know what GNU option does, I attach my notes on it -- 
> which really were not that easy to get ;-)

I'm very confused about the use and purpose of -rpath-link. It seems to 
be the equivalent of -L, but only for the purposes of searching for 
undefined symbols between shared libraries, and it also guarantees the 
path to be searched first. For this, no, Solaris LD does not have an 
equivalent; -L is your only option.

The email you referenced seemed to want to *not* use -rpath-link, but 
instead have it ignore the undefined symbol w.r.t. the shared library. 
Much of the remainder of the thread discusses how to implement this in 
binutils, as it appears that even gnu ld didn't handle this at the time. 
In this, the only option is to add "-z nodefs" to allow undefined 
symbols in the executable.

Hope this helps; let me know if you have more questions.

Christopher