[patch] Fix regression in debug info for Ada with DWARF 5

[Eric Botcazou]

Hi,

add_scalar_info can directly generate a reference to an existing DIE for a 
scalar attribute, e.g the upper bound of a VLA, but it does so only if this 
existing DIE has a location or is a constant:

              if (get_AT (decl_die, DW_AT_location)
                  || get_AT (decl_die, DW_AT_data_member_location)
                  || get_AT (decl_die, DW_AT_const_value))

Now, in DWARF 5, members of a structure that are bitfields no longer have a 
DW_AT_data_member_location but a DW_AT_data_bit_offset attribute instead, so 
the condition is bypassed.

Tested on x86-64/Linux, OK for mainline and 11 branch?


2021-08-16  Eric Botcazou  <ebotca...@adacore.com>

        * dwarf2out.c (add_scalar_info): Deal with DW_AT_data_bit_offset.

-- 
Eric Botcazou
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 4bcd3313fee..ba0a6d6ed60 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -21253,6 +21253,7 @@ add_scalar_info (dw_die_ref die, enum dwarf_attribute attr, tree value,
 	    {
 	      if (get_AT (decl_die, DW_AT_location)
 		  || get_AT (decl_die, DW_AT_data_member_location)
+		  || get_AT (decl_die, DW_AT_data_bit_offset)
 		  || get_AT (decl_die, DW_AT_const_value))
 		{
 		  add_AT_die_ref (die, attr, decl_die);