On Thu, Aug 18, 2016 at 11:33 AM, Pierre-Marie de Rodat
<[email protected]> wrote:
> Hello,
>
> For -gdwarf-3 and newer, the DWARF back-end sometimes generates DWARF
> procedures to factorize complex location descriptions. DWARF procedures
> can be materialized as DW_TAG_dwarf_procedure DIEs, but actually any DIE
> that can hold a DW_AT_location attribute is also accepted.
>
> Unlike what I thought at some point, the DW_TAG_dwarf_procedure tag was
> introduced in the DWARFv3 standard, not the DWARFv4 one, so the back-end
> can always emit DW_TAG_dwarf_procedure DIEs, as this simplifies code and
> prevents the types pruning pass from missing a DWARF procedure.
>
> Boostrapped and regtested on x86_64-linux: no regression. Ok to commit?
> Thank you in advance!
Ok.
Richard.
> gcc/
>
> * dwarf2out.c (copy_dwarf_procedure): Remove obsolete comment.
> (new_dwarf_proc_die): Emit DW_TAG_dwarf_procedure DIEs even for
> -gdwarf-3.
> (function_to_dwarf_procedure): Update comment.
> ---
> gcc/dwarf2out.c | 16 ++--------------
> 1 file changed, 2 insertions(+), 14 deletions(-)
>
> diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> index 0fdab9a..98f08b7 100644
> --- a/gcc/dwarf2out.c
> +++ b/gcc/dwarf2out.c
> @@ -7747,9 +7747,6 @@ copy_dwarf_procedure (dw_die_ref die,
> comdat_type_node *type_node,
> hash_map<dw_die_ref, dw_die_ref> &copied_dwarf_procs)
> {
> - /* We do this for COMDAT section, which is DWARFv4 specific, so
> - DWARF procedure are always DW_TAG_dwarf_procedure DIEs (unlike
> - DW_TAG_variable in DWARFv3). */
> gcc_assert (die->die_tag == DW_TAG_dwarf_procedure);
>
> /* DWARF procedures are not supposed to have children... */
> @@ -15332,22 +15329,15 @@ static dw_die_ref
> new_dwarf_proc_die (dw_loc_descr_ref location, tree fndecl,
> dw_die_ref parent_die)
> {
> - const bool dwarf_proc_supported = dwarf_version >= 4;
> dw_die_ref dwarf_proc_die;
>
> if ((dwarf_version < 3 && dwarf_strict)
> || location == NULL)
> return NULL;
>
> - dwarf_proc_die = new_die (dwarf_proc_supported
> - ? DW_TAG_dwarf_procedure
> - : DW_TAG_variable,
> - parent_die,
> - fndecl);
> + dwarf_proc_die = new_die (DW_TAG_dwarf_procedure, parent_die, fndecl);
> if (fndecl)
> equate_decl_number_to_die (fndecl, dwarf_proc_die);
> - if (!dwarf_proc_supported)
> - add_AT_flag (dwarf_proc_die, DW_AT_artificial, 1);
> add_AT_loc (dwarf_proc_die, DW_AT_location, location);
> return dwarf_proc_die;
> }
> @@ -15673,9 +15663,7 @@ function_to_dwarf_procedure (tree fndecl)
> if (dwarf_proc_die != NULL)
> return dwarf_proc_die;
>
> - /* DWARF procedures are available starting with the DWARFv3 standard, but
> - it's the DWARFv4 standard that introduces the DW_TAG_dwarf_procedure
> - DIE. */
> + /* DWARF procedures are available starting with the DWARFv3 standard. */
> if (dwarf_version < 3 && dwarf_strict)
> return NULL;
>
> --
> 2.9.3
>
