Re: debugging help?

[Alan Lehotsky <apl@alum.mit.edu>]

At 9:33 AM +1000 5/9/01, Ben Elliston wrote:

> >>>>> "lehotsky" == lehotsky  <lehotsky@earthlink.net> writes:
>
>  lehotsky> the cgen code doesn't seem to issue very useful error messages.
>  lehotsky> Any suggestions on how to track down this problem?
>
>I see Frank has already answered, this, however ..
>
>  lehotsky> Computing sformat argument buffers ...
>  lehotsky> ERROR: bad bitsize argument to gen-ifetch 4
>  lehotsky> No backtrace available.
>  lehotsky> make[1]: *** [cgen-cpu-decode] Error 1
>
>It so happens that I recognise this one.  It is often caused by
>instruction formats (the "(+ ...)" clause) missing one or more
>bits--or containing overlapping ifields.
>
>Ben


	And you're right.  I had looked at all my (+ ....) patterns and discovered that
	I had entered the SAME field twice!  If I was a "schemer" (or a conniver - sorry, old
	MIT joke....), I'd try to write code that would identify that case and issue a better warning
	message.

	Frankly, I like the cgen "language", but the error diagnostics REALLY are terrible.
	It takes a lot of fumbling around to figure out what it's really complaining about most of the
	time.....

-- Al
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