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Re: [PATCH] Support for DW_FORM_strx tag
- From: Andrew Burgess <andrew dot burgess at embecosm dot com>
- To: Ali Tamur <tamur at google dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Tue, 23 Apr 2019 13:33:38 +0100
- Subject: Re: [PATCH] Support for DW_FORM_strx tag
- References: <CAH=Am=7D_UqOSdJMtg-=o-_a_CSFAoR8h2+HgwW4QDcKefs9mg@mail.gmail.com>
* Ali Tamur via gdb-patches <gdb-patches@sourceware.org> [2019-04-22 19:07:49 -0700]:
> DW_FORM_strx is the new name of DW_FORM_GNU_str_index in the Dwarf 5
> standard.
> This is a small step towards supporting Dwarf 5 in gdb.
This looks good, with a few minor nits below...
>
> gdb/ChangeLog
> 2019-04-27 Ali Tamur <tamur@google.com>
>
> * dwarf2read.c (skip_one_die): Add DW_FORM_strx
> (read_attribute_value): Likewise
> (dwarf2_read_addr_index): Update comment
> (read_str_index): Add DW_FORM_strx
> (dwarf2_string_attr): Likewise
> (dwarf2_const_value_attr): Likewise
> (dump_die_shallow): Likewise
> (dwarf2_fetch_constant_bytes): Likewise
> (skip_form_bytes): Likewise
These should all have '.' at the end.
> ---
> gdb/dwarf2read.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 829b07f01a..09ecd4fbd4 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -9369,6 +9369,7 @@ skip_one_die (const struct die_reader_specs *reader,
> const gdb_byte *info_ptr,
> info_ptr += 4 + read_4_bytes (abfd, info_ptr);
> break;
> case DW_FORM_addrx:
> + case DW_FORM_strx:
> case DW_FORM_sdata:
> case DW_FORM_udata:
> case DW_FORM_ref_udata:
> @@ -19295,6 +19296,7 @@ read_attribute_value (const struct die_reader_specs
> *reader,
> DW_ADDR (attr) = read_addr_index_from_leb128 (cu, info_ptr,
> &bytes_read);
> info_ptr += bytes_read;
> break;
> + case DW_FORM_strx:
> case DW_FORM_GNU_str_index:
> if (reader->dwo_file == NULL)
> {
> @@ -19890,7 +19892,7 @@ dwarf2_read_addr_index (struct dwarf2_per_cu_data
> *per_cu,
> addr_size);
> }
>
> -/* Given a DW_FORM_GNU_str_index, fetch the string.
> +/* Given a DW_FORM_GNU_str_index or DW_FORM_strx, fetch the string.
> This is only used by the Fission support. */
>
> static const char *
> @@ -19907,7 +19909,7 @@ read_str_index (const struct die_reader_specs
> *reader, ULONGEST str_index)
> &reader->dwo_file->sections.str_offsets;
> const gdb_byte *info_ptr;
> ULONGEST str_offset;
> - static const char form_name[] = "DW_FORM_GNU_str_index";
> + static const char form_name[] = "DW_FORM_GNU_str_index or DW_FORM_strx";
>
> dwarf2_read_section (objfile, str_section);
> dwarf2_read_section (objfile, str_offsets_section);
> @@ -20073,6 +20075,7 @@ dwarf2_string_attr (struct die_info *die, unsigned
> int name, struct dwarf2_cu *c
> {
> if (attr->form == DW_FORM_strp || attr->form == DW_FORM_line_strp
> || attr->form == DW_FORM_string
> + || attr->form == DW_FORM_strx
Your mail client seems to have corrupted the patch slightly so I
couldn't check you had the correct tabs/spaces here. Please double
check before you commit.
> || attr->form == DW_FORM_GNU_str_index
> || attr->form == DW_FORM_GNU_strp_alt)
> str = DW_STRING (attr);
> @@ -21896,6 +21899,7 @@ dwarf2_const_value_attr (const struct attribute
> *attr, struct type *type,
> break;
> case DW_FORM_string:
> case DW_FORM_strp:
> + case DW_FORM_strx:
> case DW_FORM_GNU_str_index:
> case DW_FORM_GNU_strp_alt:
> /* DW_STRING is already allocated on the objfile obstack, point
> @@ -22900,6 +22904,7 @@ dump_die_shallow (struct ui_file *f, int indent,
> struct die_info *die)
> case DW_FORM_string:
> case DW_FORM_strp:
> case DW_FORM_line_strp:
> + case DW_FORM_strx:
Same white space check here please.
> case DW_FORM_GNU_str_index:
> case DW_FORM_GNU_strp_alt:
> fprintf_unfiltered (f, "string: \"%s\" (%s canonicalized)",
> @@ -23328,6 +23333,7 @@ dwarf2_fetch_constant_bytes (sect_offset sect_off,
> break;
> case DW_FORM_string:
> case DW_FORM_strp:
> + case DW_FORM_strx:
> case DW_FORM_GNU_str_index:
> case DW_FORM_GNU_strp_alt:
> /* DW_STRING is already allocated on the objfile obstack, point
> @@ -24293,6 +24299,7 @@ skip_form_bytes (bfd *abfd, const gdb_byte *bytes,
> const gdb_byte *buffer_end,
>
> case DW_FORM_addrx:
> case DW_FORM_sdata:
> + case DW_FORM_strx:
> case DW_FORM_udata:
> case DW_FORM_GNU_addr_index:
> case DW_FORM_GNU_str_index:
Additionally could you look at expanding 'proc _handle_DW_FORM' in
gdb/testsuite/lib/dwarf.exp to also handle DW_FORM_strx, this should
just require adding a line like this 'DW_FORM_strx -' at the correct
place.
Thanks,
Andrew