[RFA/commit/dwarf] Create partial symbols for nested subprograms

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

I just realized that we are missing the nested subprograms in our
partial symbol list.  Normally, this should cause us to fail when
trying to break on a nested procedure until we have loaded the full
symbols for that unit.  But there is in fact a bit of code that
I couldn't understand in ada_lookup_symbol_list which works around
this issue: It searches the minimal symbols for a match, derives
the associated symbol address, then determines the associated psymtab,
converts the psymtab into a symtab; Contrary to the partial symtab,
the full symtab does contain a symbol for our nested procedure, and
thus the lookup succeeds.

I stumbled on this because I am about to remove the piece of code
mentioned above (in ada_lookup_symbol_list), as it introduces
a pretty significant performance penalty - I will post a separate
patch with more details later on.  But at the same time, I think
it is important by itself, as I want the partial symtab and full
symtab to be consistent.

2008-09-10  Joel Brobecker  <brobecker@adacore.com>

        * dwarf2read.c (add_partial_subprogram): New procedure.
        (scan_partial_symbols): Use it.
        (load_partial_dies): Read in children of subprogram and lexical
        blocks.

Tested on x86-linux. No regression. I would like to commit in a week
if there are no objections.

Thanks,
-- 
Joel

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