From: Weimin Pan <weimin.pan@oracle.com>
To: "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
Cc: Wei-min Pan <weimin.pan@oracle.com>
Subject: Re: [PING 3][PATCH PR gdb/18071] TLS variables can't be resolved on aarch64-linux-gnu
Date: Wed, 24 Jan 2018 01:11:00 -0000 [thread overview]
Message-ID: <c0a7b762-24a6-3385-a0d8-a0a96c994cf7@oracle.com> (raw)
In-Reply-To: <64a638db-13e1-e692-f775-9afc19677a2a@oracle.com>
While this problem shows up in aarch64, the fix is actually
in gdb core. Pedro, would you please review the patch when
you get a chance?
Thanks.
On 1/11/2018 4:32 PM, Wei-min Pan wrote:
>
> On 11/15/2017 5:51 PM, Wei-min Pan wrote:
>>
>> On 11/2/2017 8:32 AM, Weimin Pan wrote:
>>> Running the test case with upstream gdb shows two failures:
>>>
>>> (1) Receiving different error messages when printing TLS variable
>>> before
>>> Â Â Â Â program runs - because the ARM compiler does not emit dwarf
>>> attribute
>>> Â Â Â Â DW_AT_location for TLS, the result is expected and the baseline
>>> may
>>> Â Â Â Â need to be changed for aarch64.
>>>
>>> (2) Using "info address" command on C++ static TLS object resulted in
>>> Â Â Â Â "symbol unresolved" error - below is a snippet from the test case:
>>>
>>> class K {
>>> Â public:
>>> Â Â static __thread int another_thread_local;
>>> };
>>>
>>> __thread int K::another_thread_local;
>>>
>>> (gdb) info address K::another_thread_local
>>> Symbol "K::another_thread_local" is unresolved.
>>>
>>> This patch contains fix for (2).
>>>
>>> Function info_address_command() handles the "info address" command and
>>> calls lookup_minimal_symbol_and_objfile() to find sym's symbol entry in
>>> mininal symbol table if SYMBOL_COMPUTED_OPS (sym) is false. Problem is
>>> that function lookup_minimal_symbol_and_objfile() only looked up an
>>> objfile's minsym ordinary hash table, not its demangled hash table,
>>> which
>>> was the reason why the C++ name was not found.
>>>
>>> The fix is to call lookup_minimal_symbol(), which already looks up
>>> entries
>>> in both minsym's hash tables, to find names when traversing the
>>> object file
>>> list in lookup_minimal_symbol_and_objfile().
>>>
>>> Tested in both aarch64-linux-gnu and amd64-linux-gnu. No regressions.
>>> ---
>>> Â gdb/ChangeLog |Â Â Â 5 +++++
>>> Â gdb/minsyms.c |Â Â 17 +++--------------
>>> Â 2 files changed, 8 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
>>> index 4b292e0..2f630bc 100644
>>> --- a/gdb/ChangeLog
>>> +++ b/gdb/ChangeLog
>>> @@ -1,3 +1,8 @@
>>> +2017-11-01 Weimin Pan <weimin.pan@oracle.com>
>>> +
>>> +Â Â Â * minsyms.c (lookup_minimal_symbol_and_objfile): Use
>>> +Â Â Â lookup_minimal_symbol() to find symbol entry.
>>> +
>>>  2017-10-27 Keith Seitz <keiths@redhat.com>
>>> Â Â Â Â Â Â * breakpoint.c (print_breakpoint_location): Use the symbol
>>> saved
>>> diff --git a/gdb/minsyms.c b/gdb/minsyms.c
>>> index 37edbd8..4edd8b1 100644
>>> --- a/gdb/minsyms.c
>>> +++ b/gdb/minsyms.c
>>> @@ -881,23 +881,12 @@ lookup_minimal_symbol_and_objfile (const char
>>> *name)
>>> Â {
>>> Â Â Â struct bound_minimal_symbol result;
>>> Â Â Â struct objfile *objfile;
>>> -Â unsigned int hash = msymbol_hash (name) % MINIMAL_SYMBOL_HASH_SIZE;
>>> Â Â Â Â ALL_OBJFILES (objfile)
>>> Â Â Â Â Â {
>>> -Â Â Â Â Â struct minimal_symbol *msym;
>>> -
>>> -Â Â Â Â Â for (msym = objfile->per_bfd->msymbol_hash[hash];
>>> -Â Â Â Â Â Â msym != NULL;
>>> -Â Â Â Â Â Â msym = msym->hash_next)
>>> -Â Â Â {
>>> -Â Â Â Â Â if (strcmp (MSYMBOL_LINKAGE_NAME (msym), name) == 0)
>>> -Â Â Â Â Â Â Â {
>>> -Â Â Â Â Â Â Â Â Â result.minsym = msym;
>>> -Â Â Â Â Â Â Â Â Â result.objfile = objfile;
>>> -Â Â Â Â Â Â Â Â Â return result;
>>> -Â Â Â Â Â Â Â }
>>> -Â Â Â }
>>> +Â Â Â Â Â result = lookup_minimal_symbol (name, NULL, objfile);
>>> +Â Â Â Â Â if (result.minsym != NULL)
>>> +Â Â Â Â Â Â Â return result;
>>> Â Â Â Â Â }
>>> Â Â Â Â memset (&result, 0, sizeof (result));
>>
>
next prev parent reply other threads:[~2018-01-24 1:11 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1509636764-46111-1-git-send-email-weimin.pan@oracle.com>
2017-11-16 1:53 ` [PING][PATCH " Wei-min Pan
2018-01-16 17:12 ` Yao Qi
2018-01-17 1:05 ` Weimin Pan
2018-01-17 8:57 ` Yao Qi
2018-01-18 0:18 ` Wei-min Pan
[not found] ` <515b875f-8240-b7e0-f5cc-4a26efb64b89@oracle.com>
2018-01-12 23:59 ` [PING 2][PATCH " Weimin Pan
[not found] ` <64a638db-13e1-e692-f775-9afc19677a2a@oracle.com>
2018-01-24 1:11 ` Weimin Pan [this message]
2018-02-06 1:21 ` [PING 4][PATCH " Weimin Pan
2018-03-06 1:21 ` [PING 5][PATCH " Weimin Pan
2018-03-13 18:56 ` [PING 6][PATCH " Weimin Pan
2018-03-14 21:06 ` Simon Marchi
2018-03-14 21:34 ` Wei-min Pan
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