6.8.1 compilation error

[Seth Kurtzberg]

Simon,

At this point I don't believe the problem that I reported is related to ghc,
although I'm repeating things to bolster that conclusion.

(As an aside, except for memory testing, the manufacturing test suite for
the product I'm about to discuss is written in Haskell with just a handful
of situations that required using the FFI to call C++ or C functions.)

I've done memory hardware testing in manufacturing situations, and until
quite recently I would have agreed with your characterization of memory
testing programs.  (I understand your comment was not intended to be 100%
serious, but I think it's worth answering regardless.)

We, of course, keep statistics about the accuracy of the manufacturing line
testing.  With the most recent version of memtest86, we've found the rate of
false negatives to have declined dramatically, and is now in the area of
1-2%.  The increased accuracy, of course, has a cost; on the current
platform a single testing round takes almost four hours, and I consider
three rounds to be the minimum required for thorough testing.

The point is that stand-alone memory testing is no longer useless, although
of course it is not perfect.


Seth Kurtzberg
Software Engineer
Specializing in Security, Reliability, and the Hardware/Software Interface




-----Original Message-----
From: Simon Marlow [mailto:simonmarhaskell at gmail.com] 
Sent: Monday, November 05, 2007 6:17 AM
To: Seth Kurtzberg
Cc: glasgow-haskell-users at haskell.org
Subject: Re: 6.8.1 compilation error

Seth Kurtzberg wrote:

> While compiling the new release (6.8.1, with both the primary source and 
> the extra libraries) I experienced a gcc error, gcc of course called by 
> ghc.  I'm compiling 6.8.1 with ghc 6.6.1.  The gcc version is 4.1.1.
> 
> I've seen similar behavior in the past where some sort of heap 
> corruption occurs within gcc and triggers an internal compiler error.  
> So this may not be a true ghc error at all, but one can't completely 
> rule it out.
> 
> This type of error, especially appearing at random, is suggestive of a 
> memory hardware problem.  To eliminate this possibility I ran memtest86 
> for several hours on the machine.  No errors were detected.

Dedicated memory test programs are notoriously inadequate for finding bad 
memory, whereas both GHC and GCC are actually quite good at it :-)

> I'll repeat the build again from a fresh directory to see if the problem 
> is repeatable.  Then I plan to run a build after upgrading gcc from 
> 4.1.1 to 4.2.1.  I'll report the results.

Thanks, I look forward to hearing the results.

Cheers,
	Simon