Re: Bootstrap broken on ppc-darwin

[Ian Lance Taylor <iant at google dot com>]

Andrew Pinski <pinskia@physics.uc.edu> writes:

> Here we have the same scope_labelno.  The first dbxout_begin_prologue
> comes from calling rs6000_output_mi_thunk.  The normal way
> scope_labelno gets incremented is via the
> call to debug_hooks->function_decl in rest_of_handle_final which is
> not done for thunks.
> I don't know if we should call debug_hooks->function_decl for thunks
> or not.

We shouldn't.  It doesn't make sense, since there is no proper
current_function_decl for a thunk.

Previously, scope_labelno was referenced in dbxout_block and
incremented in dbxout_function_end.  Both functions are called only by
dbxout_function_decl (a debug hook).  So it was always consistent.

Now scope_labelno is used by dbxout_begin_prologue and
dbxout_source_line.  Those are both debug hooks themselves.  So this
patch has introduced a dependency which was not previously there,
which has led to a bug.

There are several ways to fix this, of course.  I think the simplest
is going to be to always preincrement scope_labelno in
dbxout_begin_prologue, rather than postincrementing it in
dbxout_function_end.  In cases where that fails, we are already in
trouble.

Note that scope_labelno is now used for two different things: for the
LFBB symbol, and for the Lscope symbol.  It does not have to be used
for both, although as far as I can see it does no harm.

Ian