[gdb/symtab] Fix language of duplicate static minimal symbol
Commit Message
Hi,
Consider a test-case with source files msym.c:
...
static int foo (void) { return 1; }
...
and msym_main.c:
...
static int foo (void) { return 2; }
int main (void) { return 0; }
..
compiled as c++ with minimal symbols:
...
$ g++ msym_main.c msym.c
...
With objdump -x we find the two foo symbols prefixed with their corresponding
files in the symbol table:
...
0000000000000000 l df *ABS* 0000000000000000 msym_main.c
00000000004004c7 l F .text 000000000000000b _ZL3foov
0000000000000000 l df *ABS* 0000000000000000 msym.c
00000000004004dd l F .text 000000000000000b _ZL3foov
...
However, when we use gdb to print info on foo, both foos are listed, but we
get one symbol mangled and one symbol demangled:
...
$ gdb ./a.out -batch -ex "info func foo"
All functions matching regular expression "foo":
Non-debugging symbols:
0x00000000004004c7 foo()
0x00000000004004dd _ZL3foov
...
During minimal symbol reading symbol_set_names is called for each symbol.
First, it's called with foo from msym.c, an entry is created in
per_bfd->demangled_names_hash and symbol_find_demangled_name is called, which
has the side effect of setting the language of the symbol to language_cplus.
Then, it's called with foo from msym_main.c. Since
per_bfd->demangled_names_hash already has an entry for that name,
symbol_find_demangled_name is not called, and the language of the symbol
remains language_auto.
Fix this by doing the symbol_find_demangled_name call unconditionally.
Build and reg-tested on x86_64-linux.
OK for trunk?
Thanks,
- Tom
[gdb/symtab] Fix language of duplicate static minimal symbol
2018-10-30 Tom de Vries <tdevries@suse.de>
* symtab.c (symbol_set_names): Call symbol_find_demangled_name
unconditionally, to get the language of the symbol.
* gdb.base/msym.c: New test.
* gdb.base/msym.exp: New file.
* gdb.base/msym_main.c: New test.
---
gdb/symtab.c | 6 ++++--
gdb/testsuite/gdb.base/msym.c | 22 ++++++++++++++++++++++
gdb/testsuite/gdb.base/msym.exp | 25 +++++++++++++++++++++++++
gdb/testsuite/gdb.base/msym_main.c | 28 ++++++++++++++++++++++++++++
4 files changed, 79 insertions(+), 2 deletions(-)
Comments
On 10/30/18 12:11 PM, Tom de Vries wrote:
> However, when we use gdb to print info on foo, both foos are listed, but we
> get one symbol mangled and one symbol demangled:
> ...
> $ gdb ./a.out -batch -ex "info func foo"
> All functions matching regular expression "foo":
>
> Non-debugging symbols:
> 0x00000000004004c7 foo()
> 0x00000000004004dd _ZL3foov
> ...
>
Good catch!
> Build and reg-tested on x86_64-linux.
>
> OK for trunk?
I have just a few comments.
> 2018-10-30 Tom de Vries <tdevries@suse.de>
>
> * symtab.c (symbol_set_names): Call symbol_find_demangled_name
> unconditionally, to get the language of the symbol.
s/get/set/ ? When reading the patch, I originally wondered how that would help,
but symbol_find_demangled_name actually *sets* the gsymbol's language if
it is language_auto.
>
> * gdb.base/msym.c: New test.
> * gdb.base/msym.exp: New file.
> * gdb.base/msym_main.c: New test.
These entries should be listed under the testsuite ChangeLog, like:
testsuite/ChangeLog:
YYYY-MM-DD ....
* gdb.xyz/file1.c: ...
* gdb.xyz/file1.exp: ....
[https://sourceware.org/gdb/wiki/ContributionChecklist#Properly_Formatted_GNU_ChangeLog]
"msym.c" et al aren't particularly descriptive, though. Can we devise a better,
more explicit name? Something along the lines of "multiple-language-msyms.exp".
It's long, but it describes things better. [I'm not saying you should use
this name, but something other than just "msym.{c,exp}".]
Sorry, some of that is kinda nitpicky.
> diff --git a/gdb/symtab.c b/gdb/symtab.c
> index cd27a75e8c..481428f733 100644
> --- a/gdb/symtab.c
> +++ b/gdb/symtab.c
> @@ -818,6 +818,10 @@ symbol_set_names (struct general_symbol_info *gsymbol,
> else
> linkage_name_copy = linkage_name;
>
> + /* Set the symbol language. */
> + char *demangled_name = symbol_find_demangled_name (gsymbol,
> + linkage_name_copy);
> +
> entry.mangled = linkage_name_copy;
> slot = ((struct demangled_name_entry **)
> htab_find_slot (per_bfd->demangled_names_hash,
symbol_find_demangled_name returns a malloc'd string which will leak here unless
the code goes through the branch. You'll need to save the result into a
unique_xmalloc_ptr and adjust the code accordingly.
Otherwise, LGTM. Thanks very much for the patch.
Keith (IANAM*)
* I am not a maintainer, you'll need to await final review by a global maintainer.
@@ -818,6 +818,10 @@ symbol_set_names (struct general_symbol_info *gsymbol,
else
linkage_name_copy = linkage_name;
+ /* Set the symbol language. */
+ char *demangled_name = symbol_find_demangled_name (gsymbol,
+ linkage_name_copy);
+
entry.mangled = linkage_name_copy;
slot = ((struct demangled_name_entry **)
htab_find_slot (per_bfd->demangled_names_hash,
@@ -830,8 +834,6 @@ symbol_set_names (struct general_symbol_info *gsymbol,
|| (gsymbol->language == language_go
&& (*slot)->demangled[0] == '\0'))
{
- char *demangled_name = symbol_find_demangled_name (gsymbol,
- linkage_name_copy);
int demangled_len = demangled_name ? strlen (demangled_name) : 0;
/* Suppose we have demangled_name==NULL, copy_name==0, and
new file mode 100644
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2018 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/>. */
+
+static int
+foo (void)
+{
+ return 1;
+}
new file mode 100644
@@ -0,0 +1,25 @@
+# Copyright (C) 2018 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/>.
+
+standard_testfile msym_main.c msym.c
+
+if {[prepare_for_testing "failed to prepare" $testfile [list $srcfile $srcfile2] \
+ {c++}]} {
+ return -1
+}
+
+clean_restart ${testfile}
+
+gdb_test "info func foo" ".* foo\\(\\).* foo\\(\\).*"
new file mode 100644
@@ -0,0 +1,28 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2018 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/>. */
+
+static int
+foo (void)
+{
+ return 2;
+}
+
+int
+main (void)
+{
+ return 0;
+}