Re: [RFA 10/13] Remove cleanups from linux-tdep.c

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2017-11-02 18:36, Tom Tromey wrote:
> This removes some cleanups from linux-tdep.c, replacing them with
> def_vector or unique_xmalloc_ptr as appropriate.
> 
> gdb/ChangeLog
> 2017-11-02  Tom Tromey  <tom@tromey.com>
> 
> 	* linux-tdep.c (linux_core_info_proc_mappings): Use
> 	gdb::def_vector.
> 	(linux_get_siginfo_data): Return gdb::unique_xmalloc_ptr.
> 	(linux_corefile_thread): Update.

Just to be pedantic, you should mention the change to 
linux_make_mappings_corefile_notes.

> ---
>  gdb/ChangeLog    |  7 +++++++
>  gdb/linux-tdep.c | 45 ++++++++++++++-------------------------------
>  2 files changed, 21 insertions(+), 31 deletions(-)
> 
> diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
> index 83ff59faee..0350ccea16 100644
> --- a/gdb/linux-tdep.c
> +++ b/gdb/linux-tdep.c
> @@ -998,10 +998,9 @@ linux_core_info_proc_mappings (struct gdbarch
> *gdbarch, const char *args)
>  {
>    asection *section;
>    ULONGEST count, page_size;
> -  unsigned char *descdata, *filenames, *descend, *contents;
> +  unsigned char *descdata, *filenames, *descend;
>    size_t note_size;
>    unsigned int addr_size_bits, addr_size;
> -  struct cleanup *cleanup;
>    struct gdbarch *core_gdbarch = gdbarch_from_bfd (core_bfd);
>    /* We assume this for reading 64-bit core files.  */
>    gdb_static_assert (sizeof (ULONGEST) >= 8);
> @@ -1020,12 +1019,12 @@ linux_core_info_proc_mappings (struct gdbarch
> *gdbarch, const char *args)
>    if (note_size < 2 * addr_size)
>      error (_("malformed core note - too short for header"));
> 
> -  contents = (unsigned char *) xmalloc (note_size);
> -  cleanup = make_cleanup (xfree, contents);
> -  if (!bfd_get_section_contents (core_bfd, section, contents, 0, 
> note_size))
> +  gdb::def_vector<unsigned char> contents (note_size);
> +  if (!bfd_get_section_contents (core_bfd, section, contents.data (),
> +				 0, note_size))
>      error (_("could not get core note contents"));
> 
> -  descdata = contents;
> +  descdata = contents.data ();
>    descend = descdata + note_size;
> 
>    if (descdata[note_size - 1] != '\0')
> @@ -1090,8 +1089,6 @@ linux_core_info_proc_mappings (struct gdbarch
> *gdbarch, const char *args)
> 
>        filenames += 1 + strlen ((char *) filenames);
>      }
> -
> -  do_cleanups (cleanup);
>  }
> 
>  /* Implement "info proc" for a corefile.  */
> @@ -1516,7 +1513,6 @@ static char *
>  linux_make_mappings_corefile_notes (struct gdbarch *gdbarch, bfd 
> *obfd,
>  				    char *note_data, int *note_size)
>  {
> -  struct cleanup *cleanup;
>    struct linux_make_mappings_data mapping_data;
>    struct type *long_type
>      = arch_integer_type (gdbarch, gdbarch_long_bit (gdbarch), 0, 
> "long");
> @@ -1646,14 +1642,12 @@ linux_collect_thread_registers (const struct
> regcache *regcache,
>     with the size of the data.  The caller is responsible for freeing
>     the data.  */
> 
> -static gdb_byte *
> +static gdb::unique_xmalloc_ptr<gdb_byte>
>  linux_get_siginfo_data (thread_info *thread, struct gdbarch *gdbarch,
>  			LONGEST *size)
>  {
>    struct type *siginfo_type;
> -  gdb_byte *buf;
>    LONGEST bytes_read;
> -  struct cleanup *cleanups;
> 
>    if (!gdbarch_get_siginfo_type_p (gdbarch))
>      return NULL;
> @@ -1663,21 +1657,15 @@ linux_get_siginfo_data (thread_info *thread,
> struct gdbarch *gdbarch,
> 
>    siginfo_type = gdbarch_get_siginfo_type (gdbarch);
> 
> -  buf = (gdb_byte *) xmalloc (TYPE_LENGTH (siginfo_type));
> -  cleanups = make_cleanup (xfree, buf);
> +  gdb::unique_xmalloc_ptr<gdb_byte> buf
> +    ((gdb_byte *) xmalloc (TYPE_LENGTH (siginfo_type)));
> 
>    bytes_read = target_read (&current_target, 
> TARGET_OBJECT_SIGNAL_INFO, NULL,
> -			    buf, 0, TYPE_LENGTH (siginfo_type));
> +			    buf.get (), 0, TYPE_LENGTH (siginfo_type));
>    if (bytes_read == TYPE_LENGTH (siginfo_type))
> -    {
> -      discard_cleanups (cleanups);
> -      *size = bytes_read;
> -    }
> +    *size = bytes_read;
>    else
> -    {
> -      do_cleanups (cleanups);
> -      buf = NULL;
> -    }
> +    return NULL;
> 
>    return buf;

I think this could return a gdb::byte_vector, with an empty vector 
meaning that there is no value, the equivalent of NULL currently (I 
don't think we can have a siginfo type with size 0...).

Simon