[llvm] Support: Add vfs::OutputBackend and OutputFile to virtualize compiler outputs (PR #113363)

Fri Sep 5 11:04:44 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-lld-multistage-test` running on `ppc64le-lld-multistage-test` while building `llvm` at step 6 "build-stage1-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/15920

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

```
Step 6 (build-stage1-unified-tree) failure: build (failure)
...
143.123 [957/42/5686] Linking CXX executable unittests/Transforms/Vectorize/VectorizeTests
143.125 [957/41/5687] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputBackendTest.cpp.o
143.470 [957/40/5688] Linking CXX executable tools/clang/unittests/Format/FormatTests
143.471 [957/39/5689] Linking CXX executable bin/llvm-cat
143.607 [957/38/5690] Linking CXX executable bin/llvm-offload-wrapper
144.385 [957/37/5691] Linking CXX executable bin/llvm-cgdata
144.417 [957/36/5692] Linking CXX executable bin/llvm-as
144.572 [957/35/5693] Linking CXX executable unittests/ExecutionEngine/ExecutionEngineTests
144.752 [957/34/5694] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputFileTest.cpp.o
145.175 [957/33/5695] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputConfigTest.cpp.o
FAILED: unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputConfigTest.cpp.o 
ccache /usr/lib64/ccache/c++ -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage1/unittests/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/build/stage1/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googlemock/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -Wno-dangling-else -Wno-variadic-macros -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -Wno-suggest-override -MD -MT unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputConfigTest.cpp.o -MF unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputConfigTest.cpp.o.d -o unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputConfigTest.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/Support/VirtualOutputConfigTest.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/gtest-printers.h:122,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/gtest-matchers.h:49,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/internal/gtest-death-test-internal.h:47,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/gtest-death-test.h:43,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/gtest.h:65,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/Support/VirtualOutputConfigTest.cpp:11:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/Support/VirtualOutputConfigTest.cpp: In member function ‘virtual void {anonymous}::VirtualOutputConfigTest_equals_Test::TestBody()’:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/Support/VirtualOutputConfigTest.cpp:72:3:   in ‘constexpr’ expansion of ‘llvm::vfs::OutputConfig().llvm::vfs::OutputConfig::operator==(llvm::vfs::OutputConfig())’
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/internal/gtest-internal.h:1493:48: internal compiler error: in cxx_eval_bit_field_ref, at cp/constexpr.c:2683
           ::testing::AssertionResult(expression))                     \
                                                ^
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/gtest.h:1792:3: note: in expansion of macro ‘GTEST_TEST_BOOLEAN_’
   GTEST_TEST_BOOLEAN_(condition, #condition, false, true, \
   ^~~~~~~~~~~~~~~~~~~
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/third-party/unittest/googletest/include/gtest/gtest.h:1807:32: note: in expansion of macro ‘GTEST_EXPECT_TRUE’
 #define EXPECT_TRUE(condition) GTEST_EXPECT_TRUE(condition)
                                ^~~~~~~~~~~~~~~~~
/home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/unittests/Support/VirtualOutputConfigTest.cpp:72:3: note: in expansion of macro ‘EXPECT_TRUE’
   EXPECT_TRUE(OutputConfig() == OutputConfig());
   ^~~~~~~~~~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://bugzilla.redhat.com/bugzilla> for instructions.
Preprocessed source stored into /tmp/ccWXuv27.out file, please attach this to your bugreport.
145.188 [957/32/5696] Linking CXX executable unittests/FuzzMutate/FuzzMutateTests
145.381 [957/31/5697] Building AMDGPUGenAsmWriter.inc...
145.897 [957/30/5698] Linking CXX executable bin/llvm-link
147.480 [957/29/5699] Linking CXX executable unittests/Transforms/IPO/IPOTests
148.502 [957/28/5700] Building CXX object lib/Target/AVR/CMakeFiles/LLVMAVRCodeGen.dir/AVRTargetMachine.cpp.o
153.575 [957/27/5701] Building AMDGPUGenInstrInfo.inc...
153.941 [957/26/5702] Building CXX object lib/Target/AVR/CMakeFiles/LLVMAVRCodeGen.dir/AVRTargetTransformInfo.cpp.o
153.964 [957/25/5703] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/VirtualOutputBackendsTest.cpp.o
155.293 [957/24/5704] Building AMDGPUGenGlobalISel.inc...
156.712 [957/23/5705] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
159.206 [957/22/5706] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
In file included from /usr/include/c++/8/cassert:44,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-lld-multistage-test/ppc64le-lld-multistage-test/llvm-project/llvm/include/llvm/ProfileData/InstrProf.h:40,

```

</details>

https://github.com/llvm/llvm-project/pull/113363