[RFA/dwarf-2] Add support for included files

[Joel Brobecker <brobecker at gnat dot com>]

Hello,

This is a followup on:

    [RFC/dwarf-2] Add support for included files
    http://sources.redhat.com/ml/gdb-patches/2004-01/msg00015.html

Here is a reproducer in C, which mimics a situation that is
much more common on Ada (the notion of "separates").

hello.c:

        void
        say_hello (void)
        {
          printf ("Hello world.\n");
        }

foo.c:

        #include <stdio.h>

        #include "hello.c"    <--- Reproduces the "is separate"...

        int
        main (void)
        {
          say_hello ();
          return 0;
        }

We have noticed that, if compiled with dwarf-2, GDB is unable to
set a breakpoint inside hello.c using the file:lineno syntax:

        % gcc -gdwarf-2 foo.c -o foo
        % gdb foo
        (gdb) b hello.c:4
        No source file named hello.c.
        (gdb) list hello.c:4
        No source file named hello.c.

Based on the feedback from the thread referenced above, and
some more thinking, I have chosen to keep the approach used
in the my prototype, rather than trying to extract out the
code in dwarf_decode_lines() that scans the Line Number Program
and make it symtab-independent. I wasn't too keen on doing this
because the profits versus the cost of doing this weren't too
obvious to me.

I also explored the possibility of keeping this function as is,
and of calling it while building the partial symtabs. Unfortunately,
a quick code inspection of buildsym.c conviced me that it is
not obvious that this approach would work, and that it would
probably break part of the encapsulation of that module. The
main reason is that the buildsym.c module is making some assumptions
about the context while being in use (that we are currently
building full symbol tables), and playing with the context
to force it to work in my context would create a fragile
situation.

2004-02-24  J. Brobecker  <brobecker@gnat.com>

        * dwarf2read.c (dwarf2_create_include_psymtab): New function.
        (dwarf2_build_include_psymtabs): New function.
        (read_partial_die): Add new parameter. Update call to itself.
        (add_file_name): Add forward declaration.
        (dwarf2_build_psymtabs_hard): Build the psymtabs for the
        included files as well.
        (psymtab_to_symtab_1): Build the symtabs of all dependencies
        as well.
        (scan_partial_symbols): Update call to read_partial_die().
        (add_partial_structure): Likewise.
        (add_partial_enumeration): Likewise.
        (locate_pdi_sibling): Likewise.
        (dwarf_decode_lines): Add comment.

Tested on x86-linux, no differences. I will submit a new testcase
using the code above separately.

OK to apply?

Thanks,
-- 
Joel

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