Re: bootstrap failure on darwin, compare stages

[Dale Johannesen <dalej at apple dot com>]

> Dale Johannesen wrote:
>
>> 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.
>
> -da ?

Creates a bunch of dump files containing rtl of intermediate stages.

>> Compare the dump files to get some idea what phase the problem is in.
>
>  -v 'make -s file with asm output' (don't know the switch right now.)?

-S

>> Step through the compilers in parallel with the debugger, to find the 
>> place
>>    where the bad code is.
>
> I don't like to say this, but with gdb I have my probs, I remember vc++, 
> sorry.
> I find it easier to dbg a file which fails than a comparison stage. Here
> I'm unsure who/what is responsible for.

Your choice, I'm happy with gdb.  Yes, you have to walk through a lot of 
code where you don't understand what's going on, but that's how you learn 
:)

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

Bad news:  it works fine for me.  (I've got a couple of local 
modifications involving scheduling, but it's wildly unlikely that fixed 
the bootstrap.)