Re: [RFC] lookup problem in blockframe.c:inside_main_func()

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Oct 06, 2003 at 07:14:31PM -0700, Joel Brobecker wrote:
> I don't understand you suggestion, there isn't much code above the
> part I'd like to change. Maybe below?

That's what I meant, yeah.

> In any case, attached is the patch that I came up with. I tested it
> on x86-linux RH9.0 using the stock gcc/g++ there. No regression found.
> Would it be acceptable for inclusion? I can also add a dated comments
> explaining why we are doing it that way instead of using lookup_symbol.

Please do.

> > Beware, right now that minsym code may find the one which demangles to
> > main; but that should change.
> 
> Hmmm, did I do it the right way, or did I open a bad door? In the latter
> case, is there a way for me to make sure I find the right one? It seems
> pretty easy to verify that I did find the right own by comparing
> main_name() against the SYMBOL_LINKAGE_NAME, but that still would not
> help us find the right symbol :-).
> 
> 2003-10-06  J. Brobecker  <brobecker@gnat.com>
> 
> 	* blockframe.c (inside_main_func): No longer use symbol_lookup()
>         to lookup the main function symbol.

This patch looks good to me, and I can approve it, but let's give it a
little while in case anyone else has comments.  Symtab maintainers
maybe?  Is there any risk of this finding the wrong function - I can't
see any?

> Index: blockframe.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/blockframe.c,v
> retrieving revision 1.80
> diff -u -p -r1.80 blockframe.c
> --- blockframe.c	14 Sep 2003 16:32:12 -0000	1.80
> +++ blockframe.c	7 Oct 2003 01:56:40 -0000
> @@ -83,22 +83,27 @@ deprecated_inside_entry_file (CORE_ADDR 
>  int
>  inside_main_func (CORE_ADDR pc)
>  {
> +  struct minimal_symbol *msymbol;
> +
>    if (pc == 0)
>      return 1;
>    if (symfile_objfile == 0)
>      return 0;
>  
> +  msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
> +
>    /* If the addr range is not set up at symbol reading time, set it up
>       now.  This is for DEPRECATED_FRAME_CHAIN_VALID_ALTERNATE. I do
>       this for coff, because it is unable to set it up and symbol
>       reading time. */
>  
> -  if (symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC &&
> -      symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
> +  if (msymbol != NULL
> +      && symfile_objfile->ei.main_func_lowpc == INVALID_ENTRY_LOWPC
> +      && symfile_objfile->ei.main_func_highpc == INVALID_ENTRY_HIGHPC)
>      {
> -      struct symbol *mainsym;
> +      struct symbol *mainsym
> +        = find_pc_function (SYMBOL_VALUE_ADDRESS (msymbol));
>  
> -      mainsym = lookup_symbol (main_name (), NULL, VAR_DOMAIN, NULL, NULL);
>        if (mainsym && SYMBOL_CLASS (mainsym) == LOC_BLOCK)
>  	{
>  	  symfile_objfile->ei.main_func_lowpc =
> @@ -111,8 +116,6 @@ inside_main_func (CORE_ADDR pc)
>    /* Not in the normal symbol tables, see if "main" is in the partial
>       symbol table.  If it's not, then give up.  */
>    {
> -    struct minimal_symbol *msymbol
> -      = lookup_minimal_symbol (main_name (), NULL, symfile_objfile);
>      if (msymbol != NULL && MSYMBOL_TYPE (msymbol) == mst_text)
>        {
>  	struct obj_section *osect


-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer