Hey everyone. It sounds like 426 people are in for a fun weekend. It's
possible that some of you may even have bugs in your code (I know, I know,
not YOU... :) If this is you, read on...
You might be interested in trying out the 'bugpoint' tool. It can help
you when your pass crashes on a testcase. Merely tell it the input
testcase and the name of your pass, and it will try to reduce the testcase
as much as possible, trying to make your debugging a bit easier.
Usage is just like opt or analyze, but slightly more general:
$ bugpoint foo1.bc foo2.ll -pass1 -pass2 -pass3
You can give it an arbitrary number of .ll or .bc files, and you can give
it 'opt' passes or 'analyze' passes. Of course you can use
-load just
like opt or analyze.
Note that this tool will currently only help you if your pass _crashes_.
It cannot yet help with infinite loops or miscompilations. However it is
particularly useful on large testcases like spec benchmarks, but is quite
useful even on smaller multi-function testcases.
Caveats:
1. I'm quite busy this week, so I won't really be able to help if you
run
into problems with bugpoint. No warrantee expressed or implied. If
it breaks you get to keep both pieces. If it gives you a rash, sorry,
just don't scratch.
2. However, I am interested in fixing the bugs. If you run into problems
with bugpoint, please post information to the llvmbugs at cs.uiuc.edu
mailing list. When I have time, I will get the bugs fixed.
3. There is already one bugfix that is unlikely to be in your tree:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20021202/001860.html
if you get assertions in ConstantArray or ConstantStruct when running
bugpoint, this is the patch. Thanks to Misha for pointing out the
problem.
4. If bugpoint helps, I would like to hear about it. If you have
suggestions for improvement, please send them my way. Support for
debugging infinite loops and miscompilations is already planned
though. :)
Anyway, good luck with your projects. I hope you don't all hate LLVM too
much after the experience... :)
-Chris
--
http://llvm.cs.uiuc.edu/
http://www.nondot.org/~sabre/Projects/
