[BUG] build fails with libstdc++ 12.1.0

[jdoubleu]

Describe the bug
When I compile the Google benchmark library with g++ 12.1 (using libstdc++ 12.1) in C++20 mode, I get the following error:

In file included from /usr/local/include/c++/12.1.0/string:40,
                 from /__w/googletest-issue/googletest-issue/build/_deps/google-benchmark-src/include/benchmark/benchmark.h:186,
                 from /__w/googletest-issue/googletest-issue/build/_deps/google-benchmark-src/src/benchmark.cc:15:
In static member function 'static constexpr std::char_traits<char>::char_type* std::char_traits<char>::copy(char_type*, const char_type*, std::size_t)',
    inlined from 'static constexpr void std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_S_copy(_CharT*, const _CharT*, size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /usr/local/include/c++/12.1.0/bits/basic_string.h:423:21,
    inlined from 'constexpr std::__cxx11::basic_string<_CharT, _Traits, _Allocator>& std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_M_replace(size_type, size_type, const _CharT*, size_type) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /usr/local/include/c++/12.1.0/bits/basic_string.tcc:532:22,
    inlined from 'constexpr std::__cxx11::basic_string<_CharT, _Traits, _Alloc>& std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::assign(const _CharT*) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /usr/local/include/c++/12.1.0/bits/basic_string.h:1647:19,
    inlined from 'constexpr std::__cxx11::basic_string<_CharT, _Traits, _Alloc>& std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::operator=(const _CharT*) [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]' at /usr/local/include/c++/12.1.0/bits/basic_string.h:815:28,
    inlined from 'size_t benchmark::RunSpecifiedBenchmarks(BenchmarkReporter*, BenchmarkReporter*, std::string)' at /__w/googletest-issue/googletest-issue/build/_deps/google-benchmark-src/src/benchmark.cc:459:12:
/usr/local/include/c++/12.1.0/bits/char_traits.h:431:56: error: 'void* __builtin_memcpy(void*, const void*, long unsigned int)' accessing 9223372036854775810 or more bytes at offsets [2, 9223372036854775807] and 1 may overlap up to 9223372036854775813 bytes at offset -3 [-Werror=restrict]
  431 |         return static_cast<char_type*>(__builtin_memcpy(__s1, __s2, __n));

System
Which OS, compiler, and compiler version are you using:

• OS: linux
• Compiler and version: gcc 12.1.0

To reproduce
I've prepared a repository to reproduce the issue: https://github.com/jdoubleu/googlebenchmark-issue-1398
You can checkout the build output from the CI here: https://github.com/jdoubleu/googlebenchmark-issue-1398/runs/6505920315?check_suite_focus=true

Steps to reproduce the behavior:

1. checkout the latest version
2. build (and link) the library
3. See error

Expected behavior
The library compiles with the latest gcc version (including libstdc++).

Additional context
Interestingly, I get a similar error when compiling googletest. However, the build doesn't fail (see).

The error looks like some sort of an underflow in __builtin_memcpy(void*, const void*, long unsigned int) (notice the "accessing 9223372036854775810 or more bytes"). Since it is called from std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_S_copy(_CharT*, const _CharT*, size_type), it may have something to do with Unicode used with std::string?

[LebedevRI]

I'm 99% sure it's an GCC/libstdc++ bug. Could you reduce the reproducer further, down to a single 10-line function?

[jdoubleu]

I'm 99% sure it's an GCC/libstdc++ bug.

Yes, something like this. clang 14 with libc++ and VS 2022 look fine.

I've added two scripts to the repo, which build the project and the library itself inside a Docker container. You can run those on a linux host, if you've Docker installed.

When building google-benchmark with bazel, I do not get an error. I'm not sure if bazel actually uses g++ 12.1 or if the tests actually use the TEST macro, which seems to produce these errors.

[H-G-Hristov]

Looks like it builds on Ubuntu 22.04 with the provided 12.0.

[jdoubleu]

Which "provided" g++ do you mean?
On Ubuntu 22.04 I can only install gcc 11.2.0 through apt at the moment.

The CI still fails with g++ 12.1.0 (and the latest Ubuntu): https://github.com/jdoubleu/googlebenchmark-issue-1398/runs/6794168005?check_suite_focus=true

[H-G-Hristov]

There is 12.0 package in Ubuntu 22.04 that's probably the prerelease one.
https://packages.ubuntu.com/jammy/devel/

[jdoubleu]

You were right! It's a bug in gcc 12+. See the following tickets:

• https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105651
• https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105329