[libcxx-dev] gdb on libcxx-libcxxabi-libunwind-armv7-linux build bot

Tue Sep 10 12:38:01 PDT 2019

Hi Sterling,

It in indeed a python3 issue, where it is being used as default on the
bot. Besides the check_literal format issue, python3 next iteration
method has changed its name to __next__ which requires some internal
adjustments. I am not trying to fix a remaining issue with bitset 
printer.

On 09/09/2019 16:24, Adhemerval Zanella wrote:
> At least on my testing it seems the __r_ field does exist:
> 
> $ gdb ./gdb_pretty_printer_test.sh.cpp.tmp.exe
> [...]
> (gdb) b string_test
> (gdb) r
> [1]+  Stopped                 gdb ./gdb_pretty_printer_test.sh.cpp.tmp.exe
> $ fg
> [...]
> Breakpoint 1, string_test () at /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.sh.cpp:135
> 135       std::string short_string("kdjflskdjf");
> (gdb) n
> (gdb) p short_string
> $1 = {<std::__1::__basic_string_common<true>> = {<No data fields>}, static __short_mask = 1, static __long_mask = 1, 
>   __r_ = {<std::__1::__compressed_pair_elem<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__rep, 0, false>> = {__value_ = {{__l = {__cap_ = 1784965908, 
>             __size_ = 1802726502, __data_ = 0x666a64 <error: Cannot access memory at address 0x666a64>}, __s = {{__size_ = 20 '\024', __lx = 20 '\024'}, __data_ = "kdjflskdjf"}, __r = {__words = {
>               1784965908, 1802726502, 
>               6711908}}}}}, <std::__1::__compressed_pair_elem<std::__1::allocator<char>, 1, true>> = {<std::__1::allocator<char>> = {<No data fields>}, <No data fields>}, <No data fields>}, 
>   static npos = 4294967295}
> 
> The only unexpected thing is for some reason gdb is being stopped just after
> the program start (not sure how it influences the testcase or if it is something
> expected).
> 
> Also adding a 'print("VALUE_FIELD: ", value_field)' just after the value_field
> attribution I am seeing:
> 
> $ /usr/bin/gdb -nx -batch -iex "set autoload off" -ex "source /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/utils/gdb/libcxx/printers.py" -ex "python register_libcxx_printer_loader()" -ex "source /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.py" gdb_pretty_printer_test.sh.cpp.tmp.exe 2>&1 | tee _out                                                                                                                          No symbol table is loaded.  Use the "file" command.                                                                                                                                                            Breakpoint 1 at 0x1179c: file /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.sh.cpp, line 57.               Loading libc++ pretty-printers.                                                                                                                                                                                Cannot parse expression `.L1185 4 at r4'.                                                                                                                                                                         warning: Probes-based dynamic linker interface failed.                                                                                                                                                         Reverting to original interface.
> 
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".
> FAIL: /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.sh.cpp:137
> GDB printed:
>    VALUE_FIELD:  {{__l = {__cap_ = 1784965908, __size_ = 1802726502, __data_ = 0x666a64 <error: Cannot access memory at address 0x666a64>}, __s = {{__size_ = 20 '\024', __lx = 20 '\024'}, __data_ = "kdjflskdjf"}, __r = {__words = {1784965908, 1802726502, 6711908}}}}
> "kdjflskdjf"
> Value should match:
> Traceback (most recent call last):
>   File "/home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.py", line 64, in invoke
>     print("   " + check_literal)
> TypeError: Can't convert 'bytes' object to str implicitly
> terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
> 
> 
> On 09/09/2019 15:29, Sterling Augustine wrote:
>> I think the encoding failure (which would be python 2 vs 3) is a secondary failure--already deep inside the error handling. The real problem is the 
>>
>> File "/home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/utils/gdb/libcxx/printers.py", line 221, in to_string
>>     value_field = _value_of_pair_first(self.val["__r_"])
>> gdb.error: There is no member named __r_.
>>
>> Which means that maybe the test case is getting compiled or linked differently. At least in such a way that the field "__r_" doesn't exist (at least not in debug info). But I would be quite puzzled as to why this bot has a different libcxx build or debug info than all the others.
>>
>> On Mon, Sep 9, 2019 at 11:15 AM Adhemerval Zanella <adhemerval.zanella at linaro.org <mailto:adhemerval.zanella at linaro.org>> wrote:
>>
>>     Hi Sterling,
>>
>>     Maxim has asked to take a loot at it.  The failure is essentially:
>>
>>     FAIL: /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.sh.cpp:137
>>     GDB printed:
>>        <incomplete type>
>>     Value should match:
>>     Traceback (most recent call last):
>>       File "/home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.py", line 64, in invoke
>>         print("   " + check_literal)
>>     TypeError: Can't convert 'bytes' object to str implicitly
>>
>>     I am not sure if it is something related to python2/3. The system does have
>>     both installed (python 2.7.12 and 3.5.2, with 2 being the default).  I tried
>>     to issue the faulty testcase with python3, and it shows the same issue
>>
>>     I am not very familiar with this code, but trying to make peace with
>>     the types by changing it to:
>>
>>      52             else:
>>      53                 check_literal = expectation_val.string(encoding="utf-8")
>>      54                 check_literal_utf8 = check_literal.encode("utf-8")
>>      55                 test_fails = value.encode("utf-8") != check_literal_utf8
>>
>>     Also does not help either.  For the change above, the first failure shows:
>>
>>     FAIL: /home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/test/pretty_printers/gdb_pretty_printer_test.sh.cpp:137
>>     GDB printed:
>>        Traceback (most recent call last):
>>       File "/home/buildslave/buildslave/libcxx-libcxxabi-libunwind-armv8-linux-noexceptions/llvm/projects/libcxx/utils/gdb/libcxx/printers.py", line 221, in to_string
>>         value_field = _value_of_pair_first(self.val["__r_"])
>>     gdb.error: There is no member named __r_.
>>
>>     Value should match:
>>        "kdjflskdjf"
>>
>>     Which indicates that something is still missing here. I am checking if it
>>     is possible to give you direct access to the bot.
>>