From: Simon Marchi <simon.marchi@efficios.com>
To: gdb-patches@sourceware.org
Cc: Tom de Vries <tdevries@suse.de>,
Simon Marchi <simon.marchi@efficios.com>
Subject: [PATCH] gdb: fix frame passed to gdbarch_value_to_register in value_assign
Date: Thu, 11 Jan 2024 11:51:13 -0500 [thread overview]
Message-ID: <20240111165125.134100-1-simon.marchi@efficios.com> (raw)
Commit 78f2fd84e83 ("gdb: remove VALUE_REGNUM, add value::regnum")
introduced an unexpected change in value_assign. It replaced
`get_prev_frame_always (next_frame)` with `next_frame`in the call to
gdbarch_value_to_register.
This is the result of a merge error, since I previously had a patch to
change gdbarch_value_to_register to take the next frame, and later
decided to drop it. Revert that change.
Add a test based on the DWARF assembler to expose the problem and test
the fix. I also tested on ppc64le to make sure the problem reported in
PR 31231 was fixed.
Change-Id: Ib8b851287ac27a4b2e386f7b680cf65865e6aee6
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31231
---
.../assign-variable-value-to-register.exp | 86 +++++++++++++++++++
gdb/valops.c | 3 +-
2 files changed, 88 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.dwarf2/assign-variable-value-to-register.exp
diff --git a/gdb/testsuite/gdb.dwarf2/assign-variable-value-to-register.exp b/gdb/testsuite/gdb.dwarf2/assign-variable-value-to-register.exp
new file mode 100644
index 000000000000..770f665ca959
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/assign-variable-value-to-register.exp
@@ -0,0 +1,86 @@
+# Copyright 2024 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+# Test writing to a variable that is in a register that causes
+# gdbarch_value_to_register to be called. This was introduced to test
+# PR 31231 (https://sourceware.org/bugzilla/show_bug.cgi?id=31231).
+
+# This test uses a hard-coded x86-64 DWARF register number, so restrict it to
+# x86-64.
+if { ![is_x86_64_m64_target] } {
+ unsupported "unsupported architecture"
+}
+
+load_lib dwarf.exp
+
+standard_testfile main.c -dw.S
+set dwarf_file [standard_output_file $srcfile2]
+
+set st0_dwarf_regnum 33
+
+Dwarf::assemble $dwarf_file {
+ get_func_info main
+
+ cu {} {
+ DW_TAG_compile_unit {} {
+ declare_labels int_label float_label
+
+ int_label: DW_TAG_base_type {
+ { DW_AT_name int }
+ { DW_AT_byte_size 4 DW_FORM_udata }
+ { DW_AT_encoding @DW_ATE_signed }
+ }
+
+ float_label: DW_TAG_base_type {
+ { DW_AT_name float }
+ { DW_AT_byte_size 4 DW_FORM_udata }
+ { DW_AT_encoding @DW_ATE_float }
+ }
+
+ DW_TAG_subprogram {
+ { DW_AT_name main }
+ { DW_AT_low_pc $main_start DW_FORM_addr }
+ { DW_AT_high_pc $main_end DW_FORM_addr }
+ { DW_AT_type :$int_label }
+ } {
+ DW_TAG_variable {
+ { DW_AT_name foo }
+ { DW_AT_type :$float_label }
+ { DW_AT_location {
+ DW_OP_regx $::st0_dwarf_regnum
+ } SPECIAL_expr }
+ }
+ }
+ }
+ }
+}
+
+if { [prepare_for_testing "failed to prepare" $testfile \
+ [list $srcfile $dwarf_file] {nodebug}] } {
+ return
+}
+
+if { ![runto_main] } {
+ return
+}
+
+# st0 is expected to be initialized to 0.
+gdb_test "p foo" " = 0"
+
+# Set foo. This used to cause an internal error.
+gdb_test_no_output "set foo = 1234"
+
+# Confirm the value.
+gdb_test "p foo" " = 1234"
diff --git a/gdb/valops.c b/gdb/valops.c
index 16cdf1f45530..147793400d90 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -1244,7 +1244,8 @@ value_assign (struct value *toval, struct value *fromval)
/* If TOVAL is a special machine register requiring
conversion of program values to a special raw
format. */
- gdbarch_value_to_register (gdbarch, next_frame,
+ gdbarch_value_to_register (gdbarch,
+ get_prev_frame_always (next_frame),
toval->regnum (), type,
fromval->contents ().data ());
}
base-commit: fa87f8e1958b8937047e3d5fcfd8c265745710ae
--
2.43.0
next reply other threads:[~2024-01-11 16:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-11 16:51 Simon Marchi [this message]
2024-01-11 17:24 ` Tom de Vries
2024-01-11 18:08 ` Simon Marchi
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=20240111165125.134100-1-simon.marchi@efficios.com \
--to=simon.marchi@efficios.com \
--cc=gdb-patches@sourceware.org \
--cc=tdevries@suse.de \
/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).