[PATCH v2] gdb/dwarf: fix reading subprogram with DW_AT_specification (PR gdb/26693)

[Tom Tromey]

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon>     0x00000014:   DW_TAG_subprogram
Simon>                     DW_AT_name [DW_FORM_string]     ("apply")

Simon>     0x0000001b:   DW_TAG_subprogram
Simon>                     DW_AT_specification [DW_FORM_ref4]      (0x00000014 "apply")

gdb currently goes through a lot of work to support DWARF like this, but
I wish it didn't have to.  It complicates the DWARF reader -- but IIRC
both gcc and clang just emit specializations with names like
"apply<int>".  So, I wonder if we could drop support for this at some
point.

Simon> Since the caller of load_full_comp_unit knows about the existing
Simon> dwarf2_cu object for the CU we are reading (the one load_full_comp_unit
Simon> is expected to find), we can simply make it pass it down, instead of
Simon> having load_full_comp_unit look up the per-objfile map.

Sounds reasonable.

Simon> @@ -9231,12 +9233,12 @@ die_eq (const void *item_lhs, const void *item_rhs)
Simon>  static void
Simon>  load_full_comp_unit (dwarf2_per_cu_data *this_cu,
Simon>  		     dwarf2_per_objfile *per_objfile,
Simon> +		     dwarf2_cu *existing_cu,

I think a comment explaining why this is needed would be really helpful.

The patch looks good to me.  Thank you very much for the detailed
explanation.

Tom