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[review] [ARM, Thumb] Fix disassembling bug after reloading a symbol file
- From: "Luis Machado (Code Review)" <gerrit at gnutoolchain-gerrit dot osci dot io>
- To: gdb-patches at sourceware dot org
- Date: Wed, 30 Oct 2019 09:38:42 -0400
- Subject: [review] [ARM, Thumb] Fix disassembling bug after reloading a symbol file
- Auto-submitted: auto-generated
- References: <gerrit.1572442722000.I22c3e6ebe9bfedad66d56fe9656994fa1761c485@gnutoolchain-gerrit.osci.io>
- Reply-to: luis dot machado at linaro dot org, gdb-patches at sourceware dot org
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/447
......................................................................
[ARM, Thumb] Fix disassembling bug after reloading a symbol file
The speed optimization from commit 5f6cac4085c95c5339b9549dc06d4f9184184fa6
made GDB skip reloading all symbols when the same symbol file is reloaded.
As a result, ARM targets only read the mapping symbols the first time we
load a symbol file. When reloaded, the speed optimization above will
cause an early return and gdbarch_record_special_symbol won't be called to
save mapping symbol data, which in turn affects disassembling of thumb
instructions.
First load and correct disassemble output:
Dump of assembler code for function main:
0x0000821c <+0>: bx pc
0x0000821e <+2>: nop
0x00008220 <+4>: mov r0, #0
0x00008224 <+8>: bx lr
Second load and incorrect disassemble output:
Dump of assembler code for function main:
0x0000821c <+0>: bx pc
0x0000821e <+2>: nop
0x00008220 <+4>: movs r0, r0
0x00008222 <+6>: b.n 0x8966
0x00008224 <+8>: vrhadd.u16 d14, d14, d31
This happens because the mapping symbol data is stored in an objfile_key-based
container, and that data isn't preserved across the two symbol loading
operations.
The following patch fixes this by storing the mapping symbol data in a
bfd_key-based container, which doesn't change as long as the bfd is the same.
I've also added a new test to verify the correct disassemble output.
OK?
gdb/ChangeLog:
2019-01-29 Luis Machado <luis.machado@linaro.org>
* arm-tdep.c (arm_per_objfile): Rename to ...
(arm_per_bfd): ... this.
(arm_objfile_data_key): Rename to ...
(arm_bfd_data_key): ... this.
(arm_find_mapping_symbol): Adjust access to new bfd_key-based
data.
(arm_record_special_symbol): Likewise.
gdb/testsuite/ChangeLog:
2019-01-29 Luis Machado <luis.machado@linaro.org>
* gdb.arch/pr25124.S: New file.
* gdb.arch/pr25124.exp: New file.
Signed-off-by: Luis Machado <luis.machado@linaro.org>
Change-Id: I22c3e6ebe9bfedad66d56fe9656994fa1761c485
---
M gdb/arm-tdep.c
A gdb/testsuite/gdb.arch/pr25124.S
A gdb/testsuite/gdb.arch/pr25124.exp
3 files changed, 86 insertions(+), 10 deletions(-)
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 8694618..ac7f951 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -89,14 +89,14 @@
typedef std::vector<arm_mapping_symbol> arm_mapping_symbol_vec;
-struct arm_per_objfile
+struct arm_per_bfd
{
- explicit arm_per_objfile (size_t num_sections)
+ explicit arm_per_bfd (size_t num_sections)
: section_maps (new arm_mapping_symbol_vec[num_sections]),
section_maps_sorted (new bool[num_sections] ())
{}
- DISABLE_COPY_AND_ASSIGN (arm_per_objfile);
+ DISABLE_COPY_AND_ASSIGN (arm_per_bfd);
/* Information about mapping symbols ($a, $d, $t) in the objfile.
@@ -113,8 +113,8 @@
std::unique_ptr<bool[]> section_maps_sorted;
};
-/* Per-objfile data used for mapping symbols. */
-static objfile_key<arm_per_objfile> arm_objfile_data_key;
+/* Per-bfd data used for mapping symbols. */
+static bfd_key<arm_per_bfd> arm_bfd_data_key;
/* The list of available "set arm ..." and "show arm ..." commands. */
static struct cmd_list_element *setarmcmdlist = NULL;
@@ -350,7 +350,7 @@
sec = find_pc_section (memaddr);
if (sec != NULL)
{
- arm_per_objfile *data = arm_objfile_data_key.get (sec->objfile);
+ arm_per_bfd *data = arm_bfd_data_key.get (sec->objfile->obfd);
if (data != NULL)
{
unsigned int section_idx = sec->the_bfd_section->index;
@@ -8560,17 +8560,17 @@
asymbol *sym)
{
const char *name = bfd_asymbol_name (sym);
- struct arm_per_objfile *data;
+ struct arm_per_bfd *data;
struct arm_mapping_symbol new_map_sym;
gdb_assert (name[0] == '$');
if (name[1] != 'a' && name[1] != 't' && name[1] != 'd')
return;
- data = arm_objfile_data_key.get (objfile);
+ data = arm_bfd_data_key.get (objfile->obfd);
if (data == NULL)
- data = arm_objfile_data_key.emplace (objfile,
- objfile->obfd->section_count);
+ data = arm_bfd_data_key.emplace (objfile->obfd,
+ objfile->obfd->section_count);
arm_mapping_symbol_vec &map
= data->section_maps[bfd_asymbol_section (sym)->index];
diff --git a/gdb/testsuite/gdb.arch/pr25124.S b/gdb/testsuite/gdb.arch/pr25124.S
new file mode 100644
index 0000000..79f82c7
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/pr25124.S
@@ -0,0 +1,35 @@
+/* Test proper disassembling of ARM thumb instructions when reloading a symbol
+ file.
+
+ Copyright 2012-2019 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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/>. */
+
+ .syntax unified
+ .thumb
+ .text
+ .p2align 2
+ .global main
+ .thumb
+ .thumb_func
+ .type main, %function
+main:
+ bx pc
+ nop
+.code 32
+ mov r0, #0
+ bx lr
+ .size main, .-main
diff --git a/gdb/testsuite/gdb.arch/pr25124.exp b/gdb/testsuite/gdb.arch/pr25124.exp
new file mode 100644
index 0000000..a5b7bf6
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/pr25124.exp
@@ -0,0 +1,41 @@
+# Copyright 2019 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 proper disassembling of ARM thumb instructions when reloading a symbol
+# file.
+
+if {![is_aarch32_target]} then {
+ verbose "Skipping ARM tests."
+ return
+}
+
+standard_testfile .S
+
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable debug] != "" } {
+ untested "failed to compile"
+ return -1
+}
+
+gdb_test "x /i main+8"
+ "$hex <main\\+8>:\[ \t\]+bx\[ \t\]+lr"
+ "disassemble thumb instruction (1st try)"
+
+gdb_test "file $binfile" \
+ "Reading symbols from.*" \
+ "reload symbol file"
+
+gdb_test "x /i main+8"
+ "$hex <main\\+8>:\[ \t\]+bx\[ \t\]+lr"
+ "disassemble thumb instruction (2nd try)"
--
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: I22c3e6ebe9bfedad66d56fe9656994fa1761c485
Gerrit-Change-Number: 447
Gerrit-PatchSet: 1
Gerrit-Owner: Luis Machado <luis.machado@linaro.org>
Gerrit-MessageType: newchange