From: Mark Wielaard <mark@klomp.org>
To: elfutils-devel@sourceware.org
Cc: Mark Wielaard <mark@klomp.org>
Subject: [PATCH 2/3] libdw: Update acceptable forms and attributes for dwarf_getlocation.
Date: Sat, 04 Nov 2017 23:31:00 -0000 [thread overview]
Message-ID: <1509838266-10337-2-git-send-email-mark@klomp.org> (raw)
In-Reply-To: <1509838266-10337-1-git-send-email-mark@klomp.org>
dwarf_getlocation has to know which attributes can contain a DWARF
expression or location list because the form alone might be ambiguous.
Since DWARF4 there is DW_FORM_exprloc so always accept that. But for older
DWARF or location lists we cannot just check for DW_FORM_sec_offset since
that could be a reference to diffent kinds of sections (based on attribute).
Update the attribute list based on the latest DWARF5 encodings table.
Note that DW_AT_call_origin wasn't added because that seems to be a
typo in the DWARF5 spec. http://dwarfstd.org/ShowIssue.php?issue=171103.1
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
libdw/ChangeLog | 5 +++++
libdw/dwarf_getlocation.c | 26 +++++++++++++++++++++++++-
2 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 7085649..bb9e849 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,5 +1,10 @@
2017-11-03 Mark Wielaard <mark@klomp.org>
+ * dwarf_getlocation.c (attr_ok): Always accept DW_FORM_exprloc.
+ Update list of acceptable attribute codes based on DWARF5.
+
+2017-11-03 Mark Wielaard <mark@klomp.org>
+
* dwarf.h: Add DW_OP_GNU_variable_value.
2017-10-03 Mark Wielaard <mark@klomp.org>
diff --git a/libdw/dwarf_getlocation.c b/libdw/dwarf_getlocation.c
index a4a2761..c59546e 100644
--- a/libdw/dwarf_getlocation.c
+++ b/libdw/dwarf_getlocation.c
@@ -45,10 +45,34 @@ attr_ok (Dwarf_Attribute *attr)
if (attr == NULL)
return false;
- /* Must be one of the attributes listed below. */
+ /* If it is an exprloc, it is obviously OK. */
+ if (dwarf_whatform (attr) == DW_FORM_exprloc)
+ return true;
+
+ /* Otherwise must be one of the attributes listed below. Older
+ DWARF versions might have encoded the exprloc as block, and we
+ cannot easily distinquish attributes in the loclist class because
+ the same forms are used for different classes. */
switch (attr->code)
{
case DW_AT_location:
+ case DW_AT_byte_size:
+ case DW_AT_bit_offset:
+ case DW_AT_bit_size:
+ case DW_AT_lower_bound:
+ case DW_AT_bit_stride:
+ case DW_AT_upper_bound:
+ case DW_AT_count:
+ case DW_AT_allocated:
+ case DW_AT_associated:
+ case DW_AT_data_location:
+ case DW_AT_byte_stride:
+ case DW_AT_rank:
+ case DW_AT_call_value:
+ case DW_AT_call_target:
+ case DW_AT_call_target_clobbered:
+ case DW_AT_call_data_location:
+ case DW_AT_call_data_value:
case DW_AT_data_member_location:
case DW_AT_vtable_elem_location:
case DW_AT_string_length:
--
1.8.3.1
next prev parent reply other threads:[~2017-11-04 23:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-04 23:31 [PATCH 1/3] readelf: Handle DW_OP_GNU_variable_value Mark Wielaard
2017-11-04 23:31 ` Mark Wielaard [this message]
2017-11-10 15:38 ` [PATCH 2/3] libdw: Update acceptable forms and attributes for dwarf_getlocation Mark Wielaard
2017-11-04 23:31 ` [PATCH 3/3] libdw: Handle DW_OP_GNU_variable_value Mark Wielaard
2017-11-10 15:38 ` Mark Wielaard
2017-11-10 15:38 ` [PATCH 1/3] readelf: " Mark Wielaard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1509838266-10337-2-git-send-email-mark@klomp.org \
--to=mark@klomp.org \
--cc=elfutils-devel@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).