From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Lehotsky To: Ben Elliston Cc: lehotsky@earthlink.net, cgen@sourceware.cygnus.com Subject: Re: debugging help? Date: Tue, 08 May 2001 17:12:00 -0000 Message-id: References: <15096.33343.222519.11808@scooby.apac.redhat.com> X-SW-Source: 2001-q2/msg00042.html At 9:33 AM +1000 5/9/01, Ben Elliston wrote: > >>>>> "lehotsky" == lehotsky 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 -- ------------------------------------------------------------------------ Quality Software Management http://home.earthlink.net/users/~qsmgmt apl@alum.mit.edu (978)287-0435 Voice (978)808-6836 Cell (978)287-0436 Fax Software Process Improvement and Management Consulting Language Design and Compiler Implementation