On 10/24/2018 03:15 AM, Jakub Jelinek via Dwarf-Discuss wrote:
On Wed, Oct 24, 2018 at 01:00:26AM -0400, Rafik Zurob via Dwarf-Discuss wrote:
I dug up gfortran 5.4, which does not emit DW_TAG_entry_point with my
simple example program. Does anybody actually use it?
IBM XL Fortran generates it.
$ cat entry.f
subroutine foo(a)
integer a
real b
a = 5
return
entry bar(b)
b = 3.0
return
end subroutine
$
Gets the following DWARF:
That is kind of weird, because foo only has dummy argument a
and entry bar only has b, there is nothing that tells the debug info
consumer that the subprogram doesn't have (a, b) arguments.
<1><42>: Abbrev Number: 2 (DW_TAG_base_type)
<43> DW_AT_name : INTEGER
<4b> DW_AT_byte_size : 4
<4c> DW_AT_encoding : 5 (signed)
<1><51>: Abbrev Number: 2 (DW_TAG_base_type)
<52> DW_AT_name : REAL
<57> DW_AT_byte_size : 4
<58> DW_AT_encoding : 4 (float)
<1><59>: Abbrev Number: 4 (DW_TAG_subprogram)
<5a> DW_AT_name : foo
<5e> DW_AT_low_pc : 0x0
<66> DW_AT_high_pc : 128
<67> DW_AT_decl_file : 1
<68> DW_AT_decl_line : 1
<69> DW_AT_external : 1
<6a> DW_AT_frame_base : 0x0 (location list)
<2><72>: Abbrev Number: 5 (DW_TAG_formal_parameter)
<73> DW_AT_location : 3 byte block: 91 20 6 (DW_OP_fbreg: 32;
DW_OP_deref)
<77> DW_AT_name : a
<79> DW_AT_type : 0x42
<2><81>: Abbrev Number: 5 (DW_TAG_formal_parameter)
<82> DW_AT_location : 3 byte block: 91 28 6 (DW_OP_fbreg: 40;
DW_OP_deref)
<86> DW_AT_name : b
<88> DW_AT_type : 0x51
<2><90>: Abbrev Number: 6 (DW_TAG_entry_point)
<91> DW_AT_name : bar
<95> DW_AT_low_pc : 0x28
<9d> DW_AT_decl_file : 1
<9e> DW_AT_decl_line : 7
<9f> DW_AT_frame_base : 1 byte block: 6e (DW_OP_reg30
(r30))
This looks odd to me as well.
Looking at the DWARF, I would interpret it to say that foo takes two
arguments, a and b, and bar takes zero arguments. Shouldn't the
DW_TAG_formal_parameter for b be a child of the DW_TAG_entry_point,
not the DW_TAG_subprogram?
--
Michael Eager ea...@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306
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