isolating slow compile times

[Ian Lance Taylor]

Aliesha Finkel <agfinkel@yahoo.com> writes:

> I'm a developer on a large C++ application that's
> using gcc as our compiler.  We have one file that
> takes *much* longer to compile than all the others,
> thus making distributed compiles a lot less efficient.
> 
> My question is, is there any easy (automated?) way to
> isolate the problem so that I could feed back a test
> case to gcc developers?  Or am I stuck just hacking
> out pieces and iterating.  It's a very large file with
> lots of template definitions in include files, so
> trial and error  seems like an impossible task.

A smaller test case is nice but not essential.  If you are permitted
to upload the source code to a public site, then don't spend a lot of
time reducing it.  Just follow the instructions at
http://gcc.gnu.org/bugzilla/ and attach the preprocessed file.

If you can't do that, so you need to try to pin this down some other
way, then take a look at http://delta.tigris.org/.  You could probably
make the file quite a bit smaller by using a delta script which timed
the compile.

Ian