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

Simon Marchi
2017-11-03T01:43:03Z

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