[Bug fortran/23280] gfortran does not emit DW_AT_entry_point (dwarf-2) debugging info

[fxcoudert at gcc dot gnu dot org]

------- Comment #3 from fxcoudert at gcc dot gnu dot org  2009-06-13 06:10 -------
(In reply to comment #2)
> We should actually emit DW_AT_calling_convention for the main program.

We currently correctly emit DW_AT_calling_convention.

> The DW_AT_entry_point attribute is for alternate entries, which, yes,
> we should also emit but don't.

Here's an example:

  subroutine func()
    entry ent ()
  end subroutine

With intel ("ifort -c -g" followed by "readelf -wi"), we get one subprogram and
one entry point:

 <1><ba>: Abbrev Number: 3 (DW_TAG_subprogram)
     DW_AT_decl_line   : 1
     DW_AT_decl_column : 12
     DW_AT_decl_file   : 1
     DW_AT_inline      : 0      (not inlined)
     DW_AT_accessibility: 1     (public)
     DW_AT_type        : <b2>
     DW_AT_prototyped  : 0
     DW_AT_name        : func
     DW_AT_low_pc      : 0
     DW_AT_high_pc     : 0x2c
     DW_AT_external    : 1
 <2><db>: Abbrev Number: 4 (DW_TAG_entry_point)
     DW_AT_decl_line   : 2
     DW_AT_decl_column : 9
     DW_AT_decl_file   : 1
     DW_AT_name        : ent
     DW_AT_type        : <b2>
     DW_AT_static_link : 3 byte block: 76 0 6
     DW_AT_low_pc      : 0x11

while with gfortran we get three subprograms:

 <1><2d>: Abbrev Number: 2 (DW_TAG_subprogram)
     DW_AT_external    : 1
     DW_AT_name        : (indirect string, offset: 0x7a): func
     DW_AT_decl_file   : 1
     DW_AT_decl_line   : 1
     DW_AT_low_pc      : 0
     DW_AT_high_pc     : 0x10
     DW_AT_frame_base  : 0      (location list)
 <1><49>: Abbrev Number: 3 (DW_TAG_subprogram)
     DW_AT_external    : 1
     DW_AT_name        : ent
     DW_AT_decl_file   : 1
     DW_AT_decl_line   : 2
     DW_AT_low_pc      : 0x10
     DW_AT_high_pc     : 0x20
     DW_AT_frame_base  : 0x60   (location list)
 <1><65>: Abbrev Number: 4 (DW_TAG_subprogram)
     DW_AT_name        : (indirect string, offset: 0x0): master.0.func
     DW_AT_decl_file   : 1
     DW_AT_decl_line   : 3
     DW_AT_low_pc      : 0x20
     DW_AT_high_pc     : 0x2a
     DW_AT_frame_base  : 0xc0   (location list)
     DW_AT_sibling     : <92>


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23280