Re: [PATCH v3] [gdb] Create script to convert old tests into Dwarf::assemble calls.

[Tom de Vries <tdevries@suse.de>]

On 10/12/25 11:15 PM, William Ferreira wrote:
> +        Regarding DW_FORM_exprloc and DW_FORM_block:
> +            The form is replaced with SPECIAL_expr.
> +            The entries in the value are interpreted and decoded using the
> +            dwarf_operations dictionary, and replaced with their names where
> +            applicable.
> +        """
> +        s = lbrace
> +        s += self.name + " "
> +        s += self._format_value(offset_die_lookup)

I tried out the script with a test-case I'm about to commit, and ran into:
...
Traceback (most recent call last):
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 680, in <module>
     main(sys.argv)
     ~~~~^^^^^^^^^^
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 676, in main
     generator.generate()
     ~~~~~~~~~~~~~~~~~~^^
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 651, in generate
     self.generate_die(die, indent_count)
     ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 630, in generate_die
     die_lines = die.format(self.dwarf_parser.offset_to_die, indent_count)
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 303, in format
     return "\n".join(self.format_lines(offset_die_lookup, indent_count))
                      ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 405, in format_lines
     inner_lines = super().format_lines(
         offset_die_lookup,
         indent_count + 1
     )
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 271, in format_lines
     attr_line = attr.format(
         offset_die_lookup,
         indent_count=indent_count + 1
     )
   File 
"/data/vries/gdb/binutils-gdb.git/./gdb/contrib/dwarf-to-dwarf-assembler.py", 
line 205, in format
     s += self.name + " "
          ~~~~~~~~~~^~~~~
TypeError: unsupported operand type(s) for +: 'int' and 'str'
...

The problem is that gcc 15 is using dwarf6 attribute DW_AT_language_name 
with value 144 (0x90), which is unknown to the script.

Using this patch:
...
diff --git a/gdb/contrib/dwarf-to-dwarf-assembler.py 
b/gdb/contrib/dwarf-to-dwarf-assembler.py
index 4d545cf4b13..13df3c78345 100755
--- a/gdb/contrib/dwarf-to-dwarf-assembler.py
+++ b/gdb/contrib/dwarf-to-dwarf-assembler.py
@@ -202,7 +202,11 @@ class DWARFAttribute:
              applicable.
          """
          s = lbrace
-        s += self.name + " "
+        if isinstance(self.name, int):
+          s += "DW_AT_" + str(self.name)
+        else:
+          s += self.name
+        s += " "
          s += self._format_value(offset_die_lookup)

          # Only explicitly state form if it's not a reference.
...
I get:
...
             {DW_AT_language 33 DW_FORM_data1}
             {DW_AT_144 4 DW_FORM_data1}
             {DW_AT_145 201703 DW_FORM_data4}
             {DW_AT_name 
/data/vries/gdb/src/gdb/testsuite/gdb.cp/pretty-print.cc DW_FORM_line_strp}
...

I haven't looked at whether that output makes sense with the dwarf 
assembler, perhaps there's a better way, but at least this allows the 
script to finish and makes it reasonably clear what the situation is.

Thanks,
- Tom