Re: libtool and DTrace link steps

[Andreas Färber]

Hello Ralf,

Am 07.06.2008 um 03:35 schrieb Ralf Wildenhues:

> Knowing diddly about DTrace, where's its documentation?

The main DTrace resource is here:
http://www.opensolaris.org/os/community/dtrace/

A brief overview of the steps for Solaris 10 can be found here:
http://docs.sun.com/app/docs/doc/817-6223/chp-usdt?a=view

In short, on (Open)Solaris this step is required:
/usr/sbin/dtrace -32 -G -s theprovider.d -o generated.o obj1.o  
obj2.o ...
with -32 being a system-specific flag (-32/-64), theprovider.d a  
project-specific input file, and *.o being object files with or  
without probes but not yet touched by dtrace.
On Mac OS X this step does not apply, don't know about FreeBSD or QNX.

> Most likely
> trivial support can be had by writing a compiler/linker wrapper that
> runs dtrace programs as part of the build process.  Anything more
> involved needs to know about semantics and command line interface.

From libtool's output (1.5.22 on OpenSolaris 2008.05), it looks like  
--mode=link would be a promising place to investigate?

Unfortunately I don't fully understand how it all fits together...  
Libtool is being passed .lo and .la files and knows best how to get at  
the .a and PIC/non-PIC .o files. Yet I don't see an argument to  
differentiate shared, static and convenience library .la output for -- 
tag=CC --mode=link (the dtrace -G step would only be necessary for a  
shared library or executable as output). And looking closer I see that  
despite extraction later on, it is passing .a files to gcc, which  
would at least require making and using a temporary copy instead.

Is all that logic somewhere in libltdl/config/ltmain.m4sh?

Andreas