[llvm] Be explicit about what libstdc++ C++11 ABI to use (PR #154447)

Fri Aug 22 19:10:45 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-flang-rhel-clang` running on `ppc64le-flang-rhel-test` while building `llvm` at step 7 "test-build-unified-tree-check-flang-rt".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/37575

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 7 (test-build-unified-tree-check-flang-rt) failure: test (failure)
...
11.323 [2/9/32] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Namelist.cpp.o
11.395 [2/8/33] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/MatmulTranspose.cpp.o
12.258 [2/7/34] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/ExternalIOTest.cpp.o
12.288 [2/6/35] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Format.cpp.o
12.899 [2/5/36] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Matmul.cpp.o
13.232 [2/4/37] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/CommandTest.cpp.o
15.266 [2/3/38] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Transformational.cpp.o
18.838 [2/2/39] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/CharacterTest.cpp.o
24.747 [2/1/40] Building CXX object flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Reduction.cpp.o
26.379 [1/1/41] Linking CXX executable flang-rt/unittests/Runtime/RuntimeTests
FAILED: flang-rt/unittests/Runtime/RuntimeTests 
: && /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/bin/clang++ --target=powerpc64le-unknown-linux-gnu -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -Wl,--gc-sections flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/ArrayConstructor.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Assign.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/BufferTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/CharacterTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/CommandTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Complex.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/CrashHandlerFixture.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Derived.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Descriptor.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/ExternalIOTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Format.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/InputExtensions.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Inquiry.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/ListInputTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/LogicalFormatTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Matmul.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/MatmulTranspose.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/MiscIntrinsic.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Namelist.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Numeric.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/NumericalFormatTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Pointer.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Ragged.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Random.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Reduction.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/RuntimeCrashTest.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Stop.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Support.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Time.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/TemporaryStack.cpp.o flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Transformational.cpp.o -o flang-rt/unittests/Runtime/RuntimeTests  /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/lib/libLLVMSupport.a  -lpthread  /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/lib/libllvm_gtest_main.a  /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/lib/libllvm_gtest.a  -lpthread  /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/lib/clang/22/lib/powerpc64le-unknown-linux-gnu/libflang_rt.runtime.a  /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/lib/libLLVMSupport.a  -lrt  -ldl  -lpthread  -lm  /usr/lib64/libz.so  /usr/lib64/libzstd.so  /home/buildbots/llvm-external-buildbots/workers/ppc64le-flang-rhel-test/ppc64le-flang-rhel-clang-build/build/lib/libLLVMDemangle.a  -lpthread && :
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `AccessTests_TestExists_Test::TestBody()':
AccessTest.cpp:(.text._ZN27AccessTests_TestExists_Test8TestBodyEv+0x16c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `createTemporaryFile[abi:cxx11](char const*, (anonymous namespace)::AccessType const&)':
AccessTest.cpp:(.text._ZL19createTemporaryFileB5cxx11PKcRKN12_GLOBAL__N_110AccessTypeE+0x1d8): undefined reference to `llvm::Twine::str[abi:cxx11]() const'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `AccessTests_TestNotExists_Test::TestBody()':
AccessTest.cpp:(.text._ZN30AccessTests_TestNotExists_Test8TestBodyEv+0xc0): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `AccessTests_TestRead_Test::TestBody()':
AccessTest.cpp:(.text._ZN25AccessTests_TestRead_Test8TestBodyEv+0x17c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `AccessTests_TestNotRead_Test::TestBody()':
AccessTest.cpp:(.text._ZN28AccessTests_TestNotRead_Test8TestBodyEv+0x14c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `AccessTests_TestWrite_Test::TestBody()':
AccessTest.cpp:(.text._ZN26AccessTests_TestWrite_Test8TestBodyEv+0x17c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `AccessTests_TestNotWrite_Test::TestBody()':
AccessTest.cpp:(.text._ZN29AccessTests_TestNotWrite_Test8TestBodyEv+0x14c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o:AccessTest.cpp:(.text._ZN30AccessTests_TestReadWrite_Test8TestBodyEv+0x17c): more undefined references to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)' follow
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ<int, int>(char const*, char const*, int const&, int const&)':
AccessTest.cpp:(.text._ZN7testing8internal11CmpHelperEQIiiEENS_15AssertionResultEPKcS4_RKT_RKT0_[_ZN7testing8internal11CmpHelperEQIiiEENS_15AssertionResultEPKcS4_RKT_RKT0_]+0x98): undefined reference to `testing::internal::EqFailure(char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ<long, int>(char const*, char const*, long const&, int const&)':
AccessTest.cpp:(.text._ZN7testing8internal11CmpHelperEQIliEENS_15AssertionResultEPKcS4_RKT_RKT0_[_ZN7testing8internal11CmpHelperEQIliEENS_15AssertionResultEPKcS4_RKT_RKT0_]+0x98): undefined reference to `testing::internal::EqFailure(char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/AccessTest.cpp.o: In function `testing::AssertionResult::AppendMessage(testing::Message const&)':
AccessTest.cpp:(.text._ZN7testing15AssertionResult13AppendMessageERKNS_7MessageE[_ZN7testing15AssertionResult13AppendMessageERKNS_7MessageE]+0x64): undefined reference to `testing::Message::GetString[abi:cxx11]() const'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o: In function `AllocatableTest_MoveAlloc_Test::TestBody()':
Allocatable.cpp:(.text._ZN30AllocatableTest_MoveAlloc_Test8TestBodyEv+0x11c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
Allocatable.cpp:(.text._ZN30AllocatableTest_MoveAlloc_Test8TestBodyEv+0x21c): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
Allocatable.cpp:(.text._ZN30AllocatableTest_MoveAlloc_Test8TestBodyEv+0x358): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
Allocatable.cpp:(.text._ZN30AllocatableTest_MoveAlloc_Test8TestBodyEv+0x450): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
Allocatable.cpp:(.text._ZN30AllocatableTest_MoveAlloc_Test8TestBodyEv+0x584): undefined reference to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o:Allocatable.cpp:(.text._ZN30AllocatableTest_MoveAlloc_Test8TestBodyEv+0x67c): more undefined references to `testing::internal::GetBoolAssertionFailureMessage[abi:cxx11](testing::AssertionResult const&, char const*, char const*, char const*)' follow
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ<std::basic_string_view<char, std::char_traits<char> >, char [50]>(char const*, char const*, std::basic_string_view<char, std::char_traits<char> > const&, char const (&) [50])':
Allocatable.cpp:(.text._ZN7testing8internal11CmpHelperEQISt17basic_string_viewIcSt11char_traitsIcEEA50_cEENS_15AssertionResultEPKcS9_RKT_RKT0_[_ZN7testing8internal11CmpHelperEQISt17basic_string_viewIcSt11char_traitsIcEEA50_cEENS_15AssertionResultEPKcS9_RKT_RKT0_]+0xc8): undefined reference to `testing::internal::EqFailure(char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o: In function `std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > testing::PrintToString<std::basic_string_view<char, std::char_traits<char> > >(std::basic_string_view<char, std::char_traits<char> > const&)':
Allocatable.cpp:(.text._ZN7testing13PrintToStringISt17basic_string_viewIcSt11char_traitsIcEEEENSt7__cxx1112basic_stringIcS3_SaIcEEERKT_[_ZN7testing13PrintToStringISt17basic_string_viewIcSt11char_traitsIcEEEENSt7__cxx1112basic_stringIcS3_SaIcEEERKT_]+0x244): undefined reference to `testing::internal::PrintStringTo(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::ostream*)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ<unsigned long, unsigned int>(char const*, char const*, unsigned long const&, unsigned int const&)':
Allocatable.cpp:(.text._ZN7testing8internal11CmpHelperEQImjEENS_15AssertionResultEPKcS4_RKT_RKT0_[_ZN7testing8internal11CmpHelperEQImjEENS_15AssertionResultEPKcS4_RKT_RKT0_]+0x98): undefined reference to `testing::internal::EqFailure(char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/Allocatable.cpp.o: In function `testing::AssertionResult testing::internal::CmpHelperEQ<float, float>(char const*, char const*, float const&, float const&)':
Allocatable.cpp:(.text._ZN7testing8internal11CmpHelperEQIffEENS_15AssertionResultEPKcS4_RKT_RKT0_[_ZN7testing8internal11CmpHelperEQIffEENS_15AssertionResultEPKcS4_RKT_RKT0_]+0x98): undefined reference to `testing::internal::EqFailure(char const*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, bool)'
flang-rt/unittests/Runtime/CMakeFiles/RuntimeTests.dir/ArrayConstructor.cpp.o: In function `ArrayConstructor_Basic_Test::TestBody()':

```

</details>

https://github.com/llvm/llvm-project/pull/154447