Re: [PATCH] opcodes/riscv: Hide '.L0 ' fake symbols

[Jim Wilson <jimw at sifive dot com>]

On Mon, Dec 3, 2018 at 7:23 AM Andrew Burgess
<andrew.burgess@embecosm.com> wrote:
> The RISC-V assembler generates fake labels with the name '.L0 ' as
> part of the debug information (see
> gas/config/tc-riscv.h:FAKE_LABEL_NAME).

They are also used for relaxable relocations, such as a medany auipc
instruction.

> include/ChangeLog:
>         * dis-asm.h (riscv_symbol_is_valid): Declare.
>
> opcodes/ChangeLog:
>         * disassembler.c (disassemble_init_for_target): Add RISC-V
>         initialisation.
>         * riscv-dis.c (riscv_symbol_is_valid): New function.

This looks mostly OK to me, with the fix for the problem that Andreas
pointed out except that ...

> +/* Prevent use of the fake labels that are generated as part of the DWARF
> +   debug in the assembler.  The fake labels are edefined in
> +   gas/config/tc-riscv.h as FAKE_LABEL_NAME.  */
> ...
> +  return (strcmp (name, ".L0 ") != 0);

You have a comment here pointing at GAS, but there is no comment in
GAS pointing here.  The value for FAKE_LABEL_NAME has already changed
at least once in gas, so we should have a better connection here to
make sure that a future gas change won't accidentally break this
disassembler support.  Putting a comment in gas pointing here would be
OK.  Another possible solution is to move the definition of
FAKE_LABEL_NAME into include/opcodes/riscv.h, and then you can use it
directly here.  gas/config/tc-riscv.h already includes this header
file so I think this should work OK.

You also have a typo in the comment, edefined -> defined.

Jim