libbacktrace integration for _GLIBCXX_DEBUG mode
François Dumont
frs.dumont@gmail.com
Sat Nov 21 17:28:59 GMT 2020
Maybe this last patch that has been out for a while.
Here it is again rebased as some symbols have been added since my last
proposal.
François
On 14/10/20 6:10 pm, François Dumont wrote:
> After further testing this version was bugged because ld considered
> that __create_backtrace/__render_backtrace symbols existed several
> times in the different linked .o.
>
> I tried making those inline but it failed, __render_backtrace was not
> substituted anymore, only __create_backtrace was.
>
> The correct (tested) fix was to make _Error_formatter methods using
> those symbols outline. So here is the new patch.
>
>
> libstdc++: [_GLIBCXX_DEBUG] Integrate libbacktrace
>
> New _GLIBCXX_DEBUG_BACKTRACE macro to activate backtrace
> generation on
> _GLIBCXX_DEBUG assertions using libbacktrace.
>
> * config/abi/pre/gnu.ver: Add new symbols.
> * include/debug/formatter.h [_GLIBCXX_DEBUG_BACKTRACE]:
> Include <backtrace-supported.h>.
> [_GLIBCXX_DEBUG_BACKTRACE && BACKTRACE_SUPPORTED]:
> Include <backtrace.h>.
> [(!_GLIBCXX_DEBUG_BACKTRACE || !BACKTRACE_SUPPORTED) &&
> _GLIBCXX_USE_C99_STDINT_TR1]: Include <stdint.h>.
> [BACKTRACE_SUPPORTED || _GLIBCXX_USE_C99_STDINT_TR1]
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
> (__gnu_debug::__create_backtrace_state): New.
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
> (__gnu_debug::__render_backtrace): New.
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_M_print_backtrace):
> New.
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_M_backtrace_state):
> New.
> (_Error_formatter::_Error_formatter): Outline definition.
> * src/c++11/debug.cc: Include <cstring>.
> (_Print_func_t): New.
> (print_word): Use '%.*s' format in fprintf to render only
> expected
> number of chars.
> (print_raw(PrintContext&, const char*, ptrdiff_t)): New.
> (print_function(PrintContext&, const char*,
> _Print_func_t)): New.
> (print_type): Use latter.
> (print_string(PrintContext&, const char*, const
> _Parameter*, size_t)):
> Change signature to...
> (print_string(PrintContext&, const char*, ptrdiff_t, const
> _Parameter*,
> size_t)): ...this and adapt. Remove intermediate buffer to
> render input
> string.
> (print_string(PrintContext&, const char*, ptrdiff_t)): New.
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
> (print_backtrace(void*, uintptr_t, const char*, int, const
> char*)): New.
> (_Error_formatter::_M_error()): Adapt.
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
> (__gnu_debug::__create_backtrace_state): New, weak symbol.
> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
> (__gnu_debug::__render_backtrace): New, weak symbol.
> * doc/xml/manual/debug_mode.xml: Document
> _GLIBCXX_DEBUG_BACKTRACE.
> * doc/xml/manual/using.xml: Likewise.
>
> Ok to commit once I run all testsuite in _GLIBCXX_DEBUG with backtrace ?
>
> François
>
>
> On 08/10/20 9:32 pm, François Dumont wrote:
>> I eventually consider your last remark about using weak symbols to
>> inject libbacktrace calls when _GLIBCXX_DEBUG_BACKTRACE is defined.
>>
>> libstdc++: [_GLIBCXX_DEBUG] Integrate libbacktrace
>>
>> Add _GLIBCXX_DEBUG_BACKTRACE macro to ask for a backtrace on
>> _GLIBCXX_DEBUG
>> assertions using libbacktrace.
>>
>> * config/abi/pre/gnu.ver: Add new symbols.
>> * include/debug/formatter.h [_GLIBCXX_DEBUG_BACKTRACE]:
>> Include <backtrace-supported.h>.
>> [_GLIBCXX_DEBUG_BACKTRACE && BACKTRACE_SUPPORTED]:
>> Include <backtrace.h>.
>> [(!_GLIBCXX_DEBUG_BACKTRACE || !BACKTRACE_SUPPORTED) &&
>> _GLIBCXX_USE_C99_STDINT_TR1]: Include <stdint.h>.
>> [BACKTRACE_SUPPORTED || _GLIBCXX_USE_C99_STDINT_TR1]
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>> (__gnu_debug::__create_backtrace_state): New.
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>> (__gnu_debug::__render_backtrace): New.
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_M_print_backtrace):
>> New.
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_M_backtrace_state):
>> New.
>> * src/c++11/debug.cc: Include <cstring>.
>> (_Print_func_t): New.
>> (print_word): Use '%.*s' format in fprintf to render only
>> expected
>> number of chars.
>> (print_raw(PrintContext&, const char*, ptrdiff_t)): New.
>> (print_function(PrintContext&, const char*,
>> _Print_func_t)): New.
>> (print_type): Use latter.
>> (print_string(PrintContext&, const char*, const
>> _Parameter*, size_t)):
>> Change signature to...
>> (print_string(PrintContext&, const char*, ptrdiff_t,
>> const _Parameter*,
>> size_t)): ...this and adapt. Remove intermediate buffer
>> to render input
>> string.
>> (print_string(PrintContext&, const char*, ptrdiff_t)): New.
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>> (print_backtrace(void*, uintptr_t, const char*, int,
>> const char*)): New.
>> (_Error_formatter::_M_error()): Adapt.
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>> (__gnu_debug::__create_backtrace_state): New, weak symbol.
>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>> (__gnu_debug::__render_backtrace): New, weak symbol.
>> * doc/xml/manual/debug_mode.xml: Document
>> _GLIBCXX_DEBUG_BACKTRACE.
>> * doc/xml/manual/using.xml: Likewise.
>>
>> Tested under Linux x86_64.
>>
>> Ok to commit ?
>>
>> François
>>
>> On 13/06/19 10:46 pm, François Dumont wrote:
>>> Here is a new proposal which I think take into account all your
>>> remarks.
>>>
>>> I discovered the great "%.*s" printf format so I was able to do some
>>> cleanup on the function name without any allocation.
>>>
>>> I also agree that counting the '>' or '<' is not reliable so I
>>> remove this and limit the cleanup to the __cxx1998 namespace and the
>>> __ uglification, it is still better than nothing.
>>>
>>> I complete the doc as advised. I also added a note about making sure
>>> that _GLIBCXX_DEBUG_BACKTRACE is defined consistently throughout the
>>> application otherwise it would break the famous ODR rule.
>>>
>>> I introduced a _GLIBCXX_DEBUG_USE_LIBBACKTRACE to know when the
>>> system is able to handle libbacktrace even if the user didn't
>>> activate it. I could undef if when I am not building the library but
>>> I don't remember if there is a macro to signal that library is being
>>> built ?
>>>
>>> Here is an output sample now:
>>>
>>> /home/fdt/dev/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/string:177:
>>>
>>> In function:
>>> gnu_debug::basic_string<_CharT, _Traits,
>>> _Allocator>::basic_string(const
>>> _CharT*, gnu_debug::basic_string<_CharT, _Traits,
>>> _Allocator>::size_type, const _Allocator&) [with _CharT = char;
>>> _Traits
>>> = std::char_traits<char>; _Allocator = std::allocator<char>;
>>> gnu_debug::basic_string<_CharT, _Traits, _Allocator>::size_type
>>> = long
>>> unsigned int]
>>>
>>> Backtrace:
>>> 0x400afd char const* gnu_debug::check_string<char, unsigned
>>> long>(char const*, unsigned long, char const*, unsigned int, char
>>> const*)
>>> /home/fdt/dev/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/string:56
>>>
>>> 0x400afd char const* gnu_debug::check_string<char, unsigned
>>> long>(char const*, unsigned long, char const*, unsigned int, char
>>> const*)
>>> /home/fdt/dev/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/string:49
>>>
>>> 0x400afd gnu_debug::basic_string<char, std::char_traits<char>,
>>> std::allocator<char> >::basic_string(char const*, unsigned long,
>>> std::allocator<char> const&)
>>> /home/fdt/dev/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/string:177
>>>
>>> 0x400afd test01()
>>> /home/fdt/dev/gcc/git/libstdc++-v3/testsuite/21_strings/basic_string/debug/1_neg.cc:27
>>>
>>> 0x4009c8 main
>>> /home/fdt/dev/gcc/git/libstdc++-v3/testsuite/21_strings/basic_string/debug/1_neg.cc:32
>>>
>>>
>>> Error: __s != 0 || __n == 0.
>>> XFAIL: 21_strings/basic_string/debug/1_neg.cc execution test
>>>
>>> * include/debug/formatter.h [_GLIBCXX_DEBUG_BACKTRACE]:
>>> Include <backtrace-supported.h>.
>>> [_GLIBCXX_DEBUG_BACKTRACE && BACKTRACE_SUPPORTED]:
>>> Include <backtrace.h>.
>>> [(!_GLIBCXX_DEBUG_BACKTRACE || !BACKTRACE_SUPPORTED) &&
>>> _GLIBCXX_USE_C99_STDINT_TR1]: Include <stdint.h>.
>>> [BACKTRACE_SUPPORTED || _GLIBCXX_USE_C99_STDINT_TR1]
>>> (_GLIBCXX_DEBUG_USE_LIBBACKTRACE): New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](__backtrace_error_cb): New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](__backtrace_full_cb): New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](__backtrace_state): New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_Bt_full_t):
>>> New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_M_print_backtrace):
>>>
>>> New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE](_Error_formatter::_M_backtrace_state):
>>>
>>> New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>>> (_Error_formatter::_M_backtrace_full_func): New.
>>> * src/c++11/debug.cc: Include <cstring>.
>>> (_Print_func_t): New.
>>> (print_word): Use '%.*s' format in fprintf to render only expected
>>> chars.
>>> (print_raw(PrintContext&, const char*, ptrdiff_t)): New.
>>> (print_function(PrintContext&, const char*, _Print_func_t)): New.
>>> (print_type): Use latter.
>>> (print_string(PrintContext&, const char*, const _Parameter*,
>>> size_t)):
>>> Change signature to...
>>> (print_string(PrintContext&, const char*, ptrdiff_t, const
>>> _Parameter*,
>>> size_t)): ...this and adapt. Remove intermediate buffer to
>>> render input
>>> string.
>>> (print_string(PrintContext&, const char*, ptrdiff_t)): New.
>>> [_GLIBCXX_DEBUG_USE_LIBBACKTRACE]
>>> (print_backtrace(void*, uintptr_t, const char*, int, const
>>> char*)): New.
>>> (_Error_formatter::_M_error()): Adapt.
>>> * doc/xml/manual/debug_mode.xml: Document _GLIBCXX_DEBUG_BACKTRACE.
>>> * doc/xml/manual/using.xml: Likewise.
>>>
>>> Tested under Linux x86_64 normal and debug modes.
>>>
>>> Ok to commit ?
>>>
>>> François
>>>
>>>
>>
>
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