[RFA] Use gdb::byte_vector when reading section data
Joel Brobecker
brobecker@adacore.com
Sun Mar 11 14:11:00 GMT 2018
> This changes a couple of spots that read section data to use
> gdb::byte_vector rather than a cleanup.
>
> Regression tested by the buildbot. I am not certain that the buildbot
> actually tests the code in question, so I recommend careful review.
>
> gdb/ChangeLog
> 2018-03-09 Tom Tromey <tom@tromey.com>
>
> * rs6000-aix-tdep.c (rs6000_aix_core_xfer_shared_libraries_aix):
> Use gdb::byte_vector.
> * arm-tdep.c (arm_exidx_new_objfile): Use gdb::byte_vector.
FWIW, I gave this patch a careful read, and it looked sane to me.
But I only consider myself a yellow-belt-C++-student, so a careful
review from someone else would be useful too.
As far as I can tell, the buildbots include ppc-aix, so the patch
was tested there as well, so additional runs would probably not
help, right? (I am pretty sure that the shared library code is
exercised).
> ---
> gdb/ChangeLog | 6 ++++++
> gdb/arm-tdep.c | 39 +++++++++++++++------------------------
> gdb/rs6000-aix-tdep.c | 15 ++++-----------
> 3 files changed, 25 insertions(+), 35 deletions(-)
>
> diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
> index ef7e66b36a..52d3f41cee 100644
> --- a/gdb/arm-tdep.c
> +++ b/gdb/arm-tdep.c
> @@ -2040,50 +2040,41 @@ arm_obj_section_from_vma (struct objfile *objfile, bfd_vma vma)
> static void
> arm_exidx_new_objfile (struct objfile *objfile)
> {
> - struct cleanup *cleanups;
> struct arm_exidx_data *data;
> asection *exidx, *extab;
> bfd_vma exidx_vma = 0, extab_vma = 0;
> bfd_size_type exidx_size = 0, extab_size = 0;
> - gdb_byte *exidx_data = NULL, *extab_data = NULL;
> LONGEST i;
>
> /* If we've already touched this file, do nothing. */
> if (!objfile || objfile_data (objfile, arm_exidx_data_key) != NULL)
> return;
> - cleanups = make_cleanup (null_cleanup, NULL);
>
> /* Read contents of exception table and index. */
> exidx = bfd_get_section_by_name (objfile->obfd, ELF_STRING_ARM_unwind);
> + gdb::byte_vector exidx_data;
> if (exidx)
> {
> exidx_vma = bfd_section_vma (objfile->obfd, exidx);
> exidx_size = bfd_get_section_size (exidx);
> - exidx_data = (gdb_byte *) xmalloc (exidx_size);
> - make_cleanup (xfree, exidx_data);
> + exidx_data.resize (exidx_size);
>
> if (!bfd_get_section_contents (objfile->obfd, exidx,
> - exidx_data, 0, exidx_size))
> - {
> - do_cleanups (cleanups);
> - return;
> - }
> + exidx_data.data (), 0, exidx_size))
> + return;
> }
>
> extab = bfd_get_section_by_name (objfile->obfd, ".ARM.extab");
> + gdb::byte_vector extab_data;
> if (extab)
> {
> extab_vma = bfd_section_vma (objfile->obfd, extab);
> extab_size = bfd_get_section_size (extab);
> - extab_data = (gdb_byte *) xmalloc (extab_size);
> - make_cleanup (xfree, extab_data);
> + extab_data.resize (extab_size);
>
> if (!bfd_get_section_contents (objfile->obfd, extab,
> - extab_data, 0, extab_size))
> - {
> - do_cleanups (cleanups);
> - return;
> - }
> + extab_data.data (), 0, extab_size))
> + return;
> }
>
> /* Allocate exception table data structure. */
> @@ -2097,8 +2088,9 @@ arm_exidx_new_objfile (struct objfile *objfile)
> for (i = 0; i < exidx_size / 8; i++)
> {
> struct arm_exidx_entry new_exidx_entry;
> - bfd_vma idx = bfd_h_get_32 (objfile->obfd, exidx_data + i * 8);
> - bfd_vma val = bfd_h_get_32 (objfile->obfd, exidx_data + i * 8 + 4);
> + bfd_vma idx = bfd_h_get_32 (objfile->obfd, exidx_data.data () + i * 8);
> + bfd_vma val = bfd_h_get_32 (objfile->obfd,
> + exidx_data.data () + i * 8 + 4);
> bfd_vma addr = 0, word = 0;
> int n_bytes = 0, n_words = 0;
> struct obj_section *sec;
> @@ -2135,7 +2127,7 @@ arm_exidx_new_objfile (struct objfile *objfile)
> if (addr >= extab_vma && addr + 4 <= extab_vma + extab_size)
> {
> word = bfd_h_get_32 (objfile->obfd,
> - extab_data + addr - extab_vma);
> + extab_data.data () + addr - extab_vma);
> addr += 4;
>
> if ((word & 0xff000000) == 0x80000000)
> @@ -2193,7 +2185,8 @@ arm_exidx_new_objfile (struct objfile *objfile)
> && addr + 4 <= extab_vma + extab_size)
> {
> word = bfd_h_get_32 (objfile->obfd,
> - extab_data + addr - extab_vma);
> + (extab_data.data ()
> + + addr - extab_vma));
> addr += 4;
> n_bytes = 3;
> n_words = ((word >> 24) & 0xff);
> @@ -2222,7 +2215,7 @@ arm_exidx_new_objfile (struct objfile *objfile)
> while (n_words--)
> {
> word = bfd_h_get_32 (objfile->obfd,
> - extab_data + addr - extab_vma);
> + extab_data.data () + addr - extab_vma);
> addr += 4;
>
> *p++ = (gdb_byte) ((word >> 24) & 0xff);
> @@ -2243,8 +2236,6 @@ arm_exidx_new_objfile (struct objfile *objfile)
> data->section_maps[sec->the_bfd_section->index],
> &new_exidx_entry);
> }
> -
> - do_cleanups (cleanups);
> }
>
> /* Search for the exception table entry covering MEMADDR. If one is found,
> diff --git a/gdb/rs6000-aix-tdep.c b/gdb/rs6000-aix-tdep.c
> index 38c86d4cd8..e3e086c210 100644
> --- a/gdb/rs6000-aix-tdep.c
> +++ b/gdb/rs6000-aix-tdep.c
> @@ -1007,9 +1007,6 @@ rs6000_aix_core_xfer_shared_libraries_aix (struct gdbarch *gdbarch,
> {
> struct bfd_section *ldinfo_sec;
> int ldinfo_size;
> - gdb_byte *ldinfo_buf;
> - struct cleanup *cleanup;
> - LONGEST result;
>
> ldinfo_sec = bfd_get_section_by_name (core_bfd, ".ldinfo");
> if (ldinfo_sec == NULL)
> @@ -1017,19 +1014,15 @@ rs6000_aix_core_xfer_shared_libraries_aix (struct gdbarch *gdbarch,
> bfd_errmsg (bfd_get_error ()));
> ldinfo_size = bfd_get_section_size (ldinfo_sec);
>
> - ldinfo_buf = (gdb_byte *) xmalloc (ldinfo_size);
> - cleanup = make_cleanup (xfree, ldinfo_buf);
> + gdb::byte_vector ldinfo_buf (ldinfo_size);
>
> if (! bfd_get_section_contents (core_bfd, ldinfo_sec,
> - ldinfo_buf, 0, ldinfo_size))
> + ldinfo_buf.data (), 0, ldinfo_size))
> error (_("unable to read .ldinfo section from core file: %s"),
> bfd_errmsg (bfd_get_error ()));
>
> - result = rs6000_aix_ld_info_to_xml (gdbarch, ldinfo_buf, readbuf,
> - offset, len, 0);
> -
> - do_cleanups (cleanup);
> - return result;
> + return rs6000_aix_ld_info_to_xml (gdbarch, ldinfo_buf.data (), readbuf,
> + offset, len, 0);
> }
>
> static void
> --
> 2.13.6
--
Joel
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