search

llvm / llvm-project

The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.
http://llvm.org
Other
29.14k stars 12.02k forks source link

Clang/LLVM Parse Bug #63789

Closed frobnitzem closed 1 year ago

frobnitzem commented 1 year ago

While compiling a large header-based library, I ran into a segfault that appears to be coming from the Clang C++ source parser. For this particular package, the grid_generator.cc file is the only one of its cc source files that displays the error. All its other sources compile fine with llvm. I originally used a few system-specific modified LLVM 15 versions, but have since reproduced the error with basic LLVM 12 and LLVM 14. GCC 7.5 does not have the error. Apple Clang 14 on my MacBook also does not have the error.

PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.  Program arguments: clang++ -Iinc -Iinc/mpi -Iinc/dealii -Iinc/boost-1.70.0/include -std=c++14 -o tmp.o -c grid_generator.cc
1.  grid_generator.cc:6106:3: current parser token 'template'
2.  grid_generator.cc:36:1 <Spelling=inc/dealii/deal.II/base/config.h:73:32>: parsing namespace 'dealii'
3.  grid_generator.cc:42:1: parsing namespace 'dealii::double free or corruption (out)
build.sh: line 7: 3328785 Aborted                 (core dumped) clang++ -Iinc -Iinc/mpi -Iinc/dealii -Iinc/boost-1.70.0/include -std=c++14 -o tmp.o -c grid_generator.cc

A reproducer for the bug is here (in the build.sh script):

https://github.com/frobnitzem/llvm-parse-bug1

Changing the text of the source file slightly around the indicated error token does not resolve the issue, but sometimes causes the error message to blame a file location thousands of lines away (e.g. 3059,2023, etc.). Other versions of Clang have more verbose output. In particular, Cray Clang version 15.0.0 (324a8e7de6a18594c06a0ee5d8c0eda2109c6ac6) shows:

...
#     define BOOST_HAS_TRIVIAL_ASSIGN(T) (__has_trivial_assign(T) && !is_volatile<T>::value && is_assignable<T&, const T&>::value)
                                          ^
inc/boost-1.70.0/include/boost/signals2/detail/auto_buffer.hpp:157:51: note: in instantiation of template class 'boost::has_trivial_assign<boost::variant<boost::shared_ptr<void>, boost::signals2::detail::foreign_void_shared_ptr>>' requested here
        typedef typename boost::mpl::if_c< boost::has_trivial_assign<T>::value
                                                  ^
inc/boost-1.70.0/include/boost/signals2/detail/slot_call_iterator.hpp:65:27: note: in instantiation of template class 'boost::signals2::detail::auto_buffer<boost::variant<boost::shared_ptr<void>, boost::signals2::detail::foreign_void_shared_ptr>, boost::signals2::detail::store_n_objects<10>>' requested here
        tracked_ptrs_type tracked_ptrs;
                          ^
Didn't find this decl on its identifier's chain!
UNREACHABLE executed at /home/jenkins/clang/lib/Sema/IdentifierResolver.cpp:82!
PLEASE submit a bug report to Cray and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.  Program arguments: clang++ -Iinc -Iinc/mpi -Iinc/dealii -Iinc/boost-1.70.0/include -std=c++14 -o tmp.o -c grid_generator.cc
1.  grid_generator.cc:6106:3: current parser token 'template'
2.  grid_generator.cc:36:1 <Spelling=inc/dealii/deal.II/base/config.h:394:32>: parsing namespace 'dealii'
3.  grid_generator.cc:42:1: parsing namespace 'dealii::GridGenerator'
4.  grid_generator.cc:5898:3: parsing function body 'dealii::GridGenerator::hyper_shell<3>'
 #0 0x00000000038ef25f PrintStackTraceSignalHandler(void*) Signals.cpp:0:0
 #1 0x00000000038ec9c3 llvm::sys::CleanupOnSignal(unsigned long) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x38ec9c3)
 #2 0x0000000003828387 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f0bb27f78bf (/lib64/libpthread.so.0+0x168bf)
 #4 0x00007f0bb14dbcba raise (/lib64/libc.so.6+0x4acba)
 #5 0x00007f0bb14dd354 abort (/lib64/libc.so.6+0x4c354)
 #6 0x0000000003836719 llvm::llvm_unreachable_internal(char const*, char const*, unsigned int) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x3836719)
 #7 0x0000000005a62466 clang::IdentifierResolver::IdDeclInfo::RemoveDecl(clang::NamedDecl*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5a62466)
 #8 0x0000000005a629ab clang::IdentifierResolver::RemoveDecl(clang::NamedDecl*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5a629ab)
 #9 0x0000000005c35e56 clang::Sema::ActOnPopScope(clang::SourceLocation, clang::Scope*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5c35e56)
#10 0x000000000594c824 clang::Parser::ExitScope() (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x594c824)
#11 0x0000000005a26e1c clang::Parser::ParseFunctionStatementBody(clang::Decl*, clang::Parser::ParseScope&) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5a26e1c)
#12 0x0000000005956326 clang::Parser::ParseFunctionDefinition(clang::ParsingDeclarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::LateParsedAttrList*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5956326)
#13 0x0000000005a38223 clang::Parser::ParseSingleDeclarationAfterTemplate(clang::DeclaratorContext, clang::Parser::ParsedTemplateInfo const&, clang::ParsingDeclRAIIObject&, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5a38223)
#14 0x0000000005a4526d clang::Parser::ParseTemplateDeclarationOrSpecialization(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5a4526d)
#15 0x0000000005a4550c clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5a4550c)
#16 0x0000000005987ba4 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5987ba4)
#17 0x000000000595898b clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x595898b)
#18 0x000000000599ba16 clang::Parser::ParseInnerNamespace(llvm::SmallVector<clang::Parser::InnerNamespaceInfo, 4u> const&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x599ba16)
#19 0x000000000599eae8 clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x599eae8)
#20 0x0000000005987d99 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5987d99)
#21 0x000000000595898b clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x595898b)
#22 0x000000000599ba16 clang::Parser::ParseInnerNamespace(llvm::SmallVector<clang::Parser::InnerNamespaceInfo, 4u> const&, unsigned int, clang::SourceLocation&, clang::ParsedAttributes&, clang::BalancedDelimiterTracker&) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x599ba16)
#23 0x000000000599eae8 clang::Parser::ParseNamespace(clang::DeclaratorContext, clang::SourceLocation&, clang::SourceLocation) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x599eae8)
#24 0x0000000005987d99 clang::Parser::ParseDeclaration(clang::DeclaratorContext, clang::SourceLocation&, clang::ParsedAttributes&, clang::ParsedAttributes&, clang::SourceLocation*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5987d99)
#25 0x000000000595898b clang::Parser::ParseExternalDeclaration(clang::ParsedAttributes&, clang::ParsingDeclSpec*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x595898b)
#26 0x000000000595991d clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&, clang::Sema::ModuleImportState&) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x595991d)
#27 0x0000000005949941 clang::ParseAST(clang::Sema&, bool, bool) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x5949941)
#28 0x00000000044cdd98 clang::FrontendAction::Execute() (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x44cdd98)
#29 0x000000000444a635 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x444a635)
#30 0x000000000459807a clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x459807a)
#31 0x0000000000e1eaa9 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0xe1eaa9)
#32 0x0000000000e1989b ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#33 0x00000000042787d4 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#34 0x00000000038284f3 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x38284f3)
#35 0x000000000427a9e5 clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x427a9e5)
#36 0x000000000423c24e clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x423c24e)
#37 0x000000000423d4ac clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x423d4ac)
#38 0x000000000424c99b clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0x424c99b)
#39 0x0000000000e1badd clang_main(int, char**) (/opt/cray/pe/cce/15.0.0/cce-clang/x86_64/bin/clang-15+0xe1badd)
#40 0x00007f0bb14c629c __libc_start_main (/lib64/libc.so.6+0x3529c)
#41 0x0000000000e16b49 _start /home/abuild/rpmbuild/BUILD/glibc-2.31/csu/../sysdeps/x86_64/start.S:120:0
clang-15: error: clang frontend command failed with exit code 134 (use -v to see invocation)
llvmbot commented 1 year ago

@llvm/issue-subscribers-clang-frontend

EugeneZelenko commented 1 year ago

Could you please try 16 or main branch? https://godbolt.org should be helpful.

frobnitzem commented 1 year ago

Trying on the main branch from this morning it appears to be fixed.

$ clang++ --version
clang version 17.0.0 (https://github.com/llvm/llvm-project 7d6c2e18114de9900d1b012cf9c219803b183f63)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/llvm-main-46f6kmxz64vnu2h74z456bbjwaobzcik/bin

I was unable to build llvm-16.0.6 using the same method that worked for main:

==> llvm: Executing phase: 'cmake'
==> Error: ProcessError: Command exited with status 1:
    '/spack-envs/base/opt/linux-sles15-x86_64/gcc-7.5.0/cmake-3.23.2-4r4mpiba7cwdw2hlakh5i7tchi64s3qd/bin/cmake' '-G' 'Ninja' '-DCMAKE_INSTALL_PREFIX:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/llvm-git.llvmorg-16.0.6-o66ymj6pmpgrbvu4bqtlvfbt27wvyyeu' '-DCMAKE_BUILD_TYPE:STRING=Release' '-DBUILD_TESTING:BOOL=OFF' '-DCMAKE_INTERPROCEDURAL_OPTIMIZATION:BOOL=OFF' '-DCMAKE_INSTALL_RPATH_USE_LINK_PATH:BOOL=ON' '-DCMAKE_INSTALL_RPATH:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/llvm-git.llvmorg-16.0.6-o66ymj6pmpgrbvu4bqtlvfbt27wvyyeu/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/llvm-git.llvmorg-16.0.6-o66ymj6pmpgrbvu4bqtlvfbt27wvyyeu/lib64;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/binutils-2.40-rg6g4yyiqdzmc5ejmejezyt7d2xb3wmj/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/zlib-1.2.13-abrb3atbm7o5fggx4vybpt7g4ydwtpih/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/hwloc-2.9.0-zzjts67h2facfzs3tezbjdfb3dtdgvde/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libpciaccess-0.16-mapeygkvvng2dilnbjb7ukkhpmcswxm2/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libxml2-2.10.3-rvhmalp7pdtbgsdd6pthjow2kf4nugvk/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libiconv-1.17-6m3ig2mpx2wioaqiortrj3ijoepbh3rs/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/xz-5.4.1-dyb23ip5utjeinb4aj4sccaemvawhvqu/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/ncurses-6.4-ofauveglil4rftaqtbwhgttdtd5drsqu/lib;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libedit-3.1-20210216-yquigse5fctuujerftzgfnavbuqxk67x/lib;/opt/rocm-5.4.0' '-DCMAKE_PREFIX_PATH:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/perl-data-dumper-2.173-7oaxd4wc4uwh3bbshuveosl3m3tc2rzk;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/ninja-1.11.1-komdbdics63iafimoqgc6rs72l7nmfsh;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/python-3.10.8-rk6whgdavdt3uyqhx5m5xd6554fz6ti3;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libedit-3.1-20210216-yquigse5fctuujerftzgfnavbuqxk67x;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/hwloc-2.9.0-zzjts67h2facfzs3tezbjdfb3dtdgvde;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libpciaccess-0.16-mapeygkvvng2dilnbjb7ukkhpmcswxm2;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/binutils-2.40-rg6g4yyiqdzmc5ejmejezyt7d2xb3wmj;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/ncurses-6.4-ofauveglil4rftaqtbwhgttdtd5drsqu;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libxml2-2.10.3-rvhmalp7pdtbgsdd6pthjow2kf4nugvk;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/zlib-1.2.13-abrb3atbm7o5fggx4vybpt7g4ydwtpih;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/xz-5.4.1-dyb23ip5utjeinb4aj4sccaemvawhvqu;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/pkgconf-1.8.0-oizcqfus423o3zrvufjxaxlldkg4azgh;/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/libiconv-1.17-6m3ig2mpx2wioaqiortrj3ijoepbh3rs;/spack-envs/base/opt/linux-sles15-x86_64/gcc-7.5.0/cmake-3.23.2-4r4mpiba7cwdw2hlakh5i7tchi64s3qd' '-DLLVM_REQUIRES_RTTI:BOOL=ON' '-DLLVM_ENABLE_RTTI:BOOL=ON' '-DLLVM_ENABLE_EH:BOOL=ON' '-DLLVM_ENABLE_LIBXML2:BOOL=OFF' '-DCLANG_DEFAULT_OPENMP_RUNTIME:STRING=libomp' '-DPYTHON_EXECUTABLE:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/python-3.10.8-rk6whgdavdt3uyqhx5m5xd6554fz6ti3/bin/python3.10' '-DLIBOMP_USE_HWLOC:BOOL=ON' '-DLIBOMP_HWLOC_INSTALL_DIR:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/hwloc-2.9.0-zzjts67h2facfzs3tezbjdfb3dtdgvde' '-DPython3_EXECUTABLE:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/python-3.10.8-rk6whgdavdt3uyqhx5m5xd6554fz6ti3/bin/python3.10' '-DCUDA_TOOLKIT_ROOT_DIR:STRING=IGNORE' '-DCUDA_SDK_ROOT_DIR:STRING=IGNORE' '-DCUDA_NVCC_EXECUTABLE:STRING=IGNORE' '-DLIBOMPTARGET_DEP_CUDA_DRIVER_LIBRARIES:STRING=IGNORE' '-DLIBOMPTARGET_ENABLE_DEBUG:BOOL=OFF' '-DLLDB_ENABLE_LIBEDIT:BOOL=ON' '-DLLDB_ENABLE_CURSES:BOOL=ON' '-DLLVM_ENABLE_TERMINFO:BOOL=ON' '-DLLDB_ENABLE_LIBXML2:BOOL=OFF' '-DLLDB_DISABLE_PYTHON:BOOL=ON' '-DLLVM_BINUTILS_INCDIR:STRING=/spack-manager/spack/opt/spack/linux-sles15-zen3/clang-15.0.0/binutils-2.40-rg6g4yyiqdzmc5ejmejezyt7d2xb3wmj/include' '-DLINK_POLLY_INTO_TOOLS:BOOL=ON' '-DBUILD_SHARED_LIBS:BOOL=OFF' '-DLLVM_BUILD_LLVM_DYLIB:BOOL=ON' '-DLLVM_LINK_LLVM_DYLIB:BOOL=OFF' '-DLLVM_USE_SPLIT_DWARF:BOOL=OFF' '-DLIBCXX_ENABLE_STATIC_ABI_LIBRARY:BOOL=ON' '-DLLVM_TARGETS_TO_BUILD:STRING=X86' '-DLIBOMP_TSAN_SUPPORT:BOOL=OFF' '-DLLVM_ENABLE_PROJECTS:STRING=lldb;clang;clang-tools-extra;openmp;lld;compiler-rt;libcxx;libcxxabi;libunwind;polly' '/spack-manager/stage/spack-stage-llvm-git.llvmorg-16.0.6-o66ymj6pmpgrbvu4bqtlvfbt27wvyyeu/spack-src/llvm'

1 error found in build log:
     13    -- Detecting C compile features - done
     14    -- Detecting CXX compiler ABI info
     15    -- Detecting CXX compiler ABI info - done
     16    -- Check for working CXX compiler: /spack-manager/spack/lib/spack/env/clang/clang++ - skipped
     17    -- Detecting CXX compile features
     18    -- Detecting CXX compile features - done
  >> 19    CMake Error at CMakeLists.txt:139 (MESSAGE):
     20      libcxx isn't a known project:
     21      bolt;clang;clang-tools-extra;compiler-rt;cross-project-tests;libc;
           libclc;lld;lldb;mlir;openmp;polly;pstl;flang.
     22      Did you mean to enable it as a runtime in LLVM_ENABLE_RUNTIMES?
     23    
     24    
     25    -- Configuring incomplete, errors occurred!
frobnitzem commented 1 year ago

The bug is not present in 15.0.7 either. Apparently it was only present in earlier patch-levels.

I'm closing this ticket based on this.

$ clang++ --version
clang version 15.0.7 (https://github.com/llvm/llvm-project 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
Target: x86_64-unknown-linux-gnu
Thread model: posix