Re: [PATCH][debug] Fix handling of vlas in lto

[Eric Botcazou]

> 2018-08-17  Tom de Vries  <tdevr...@suse.de>
> 
>       * dwarf2out.c (add_scalar_info): Don't add reference to existing die
>       unless the referenced die describes the added property using
>       DW_AT_location or DW_AT_const_value.  Fall back to exprloc case.
>       Otherwise, add a DW_AT_location to the referenced die.

This breaks Ada though, i.e. any array type whose bound depends on a 
discriminant is affected:

   type Array_Type is array (Integer range <>) of Integer;
   type Record_Type (N : Integer) is record
      A : Array_Type (1 .. N);
   end record;

        .uleb128 0x6    # (DIE (0x66) DW_TAG_array_type)
        .long   .LASF5  # DW_AT_name: "p__record_type__T4s"
        .long   0x34    # DW_AT_type
        .long   0x79    # DW_AT_sibling
        .uleb128 0x7    # (DIE (0x73) DW_TAG_subrange_type)
        .long   0x2d    # DW_AT_type
        .byte   0       # end of children of DIE 0x66

Testcase attached, compile with -fgnat-encodings=minimal.

-- 
Eric Botcazou
package P is

   type Array_Type is array (Integer range <>) of Integer;
   type Record_Type (N : Integer := 16) is record
      A : Array_Type (1 .. N);
   end record;

   R : Record_Type;

end P;