bootstrap failure on darwin, compare stages

[Dale Johannesen]

On Friday, September 21, 2001, at 12:37 PM, Andreas Tobler wrote:

> Hi all,
>
> since yesterday bootstrapping fails on darwin. My question is not 'what
> is the fix' I'd like to know how to track down the problem.
> Unfortunately the trapping fails in the stage of comparing the stage 1
> with 2. The failing part is insn-emit.o which differs. How can I find
> out what's going wrong?

I usually approach it this way:
Get a "good" compiler (built with cc, usually) and the "bad" (stage2) 
compiler.
Compile the file that differs with both compilers using -da.
Compare the dump files to get some idea what phase the problem is in.
Step through the compilers in parallel with the debugger, to find the place
   where the bad code is.

I haven't bootstrapped recently, I'll try it now.