Re: Debugging the GCC compiler proper 'cc1'

[Alexandre Oliva <aoliva at redhat dot com>]

On Jan 19, 2001, "Mahadev K Cholachagudda" <kcmahadev@zilogindia.com> wrote:

> (gdb) b yyparse
> Breakpoint 2 at 0x16aaf4: file /opt/gnu/share/bison.simple, line 225.

> As can be seen from the above description,
> when breakpoint is set in yyparse()
> it is neither set at c-parse.y file nor in the
> corresponding bison generated file c-parse.c

> It is getting set at location bison.simple.

> What is the reason for this behaviour and
> Are we missing something here.

The reason is that bison's output includes the `bison.simple' file
preceded by a `#line' directive, so that the debugger knows where the
file came from.  In my case, it looks like this:

#line 3 "/n/gnu/bison-1.28/share/bison.simple"
/* This file comes from bison-1.28.  */
...

> How to debug the gcc code as it passes
> through the various reductions in the LALR
> parser genrated by the bison?

I suggest adding some debugging options to the invocation of bison.
Single-stepping through bison's parsing engine is probably not a good
idea.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me

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