libc++ change causes a segmentation fault when running some lldb tests

[gulfemsavrun]

We started seeing a segmentation fault while running some lldb tests after #134960.

--

********************
PASS: lldb-api :: commands/process/attach/attach_denied/TestAttachDenied.py (160 of 2740)
UNRESOLVED: lldb-api :: commands/expression/import-std-module/non-module-type-separation/TestNonModuleTypeSeparation.py (161 of 2740)
******************** TEST 'lldb-api :: commands/expression/import-std-module/non-module-type-separation/TestNonModuleTypeSeparation.py' FAILED ********************
Script:
--
/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/bin/python3 /b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/b/s/w/ir/x/w/llvm_build/./lib --env LLVM_INCLUDE_DIR=/b/s/w/ir/x/w/llvm_build/include --env LLVM_TOOLS_DIR=/b/s/w/ir/x/w/llvm_build/./bin --arch x86_64 --build-dir /b/s/w/ir/x/w/llvm_build/lldb-test-build.noindex --lldb-module-cache-dir /b/s/w/ir/x/w/llvm_build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /b/s/w/ir/x/w/llvm_build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /b/s/w/ir/x/w/llvm_build/./bin/lldb --compiler /b/s/w/ir/x/w/cipd/clang/bin/clang --dsymutil /b/s/w/ir/x/w/llvm_build/./bin/dsymutil --make /b/s/w/ir/x/w/cipd/bin/make --llvm-tools-dir /b/s/w/ir/x/w/llvm_build/./bin --lldb-obj-root /b/s/w/ir/x/w/llvm_build/tools/lldb --lldb-libs-dir /b/s/w/ir/x/w/llvm_build/./lib --skip-category=pexpect /b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/commands/expression/import-std-module/non-module-type-separation -p TestNonModuleTypeSeparation.py
--
Exit Code: -11

Command Output (stdout):
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lldb version 21.0.0git (https://llvm.googlesource.com/a/llvm-project revision e9280a1d39af88468ffea9a14fad5bf96d51d6e6)
  clang revision e9280a1d39af88468ffea9a14fad5bf96d51d6e6
  llvm revision e9280a1d39af88468ffea9a14fad5bf96d51d6e6

--
Command Output (stderr):
--
UNSUPPORTED: LLDB (/b/s/w/ir/x/w/cipd/clang/bin/clang-x86_64) :: test_dsym (TestNonModuleTypeSeparation.TestCase.test_dsym) (test case does not fall in any category of interest for this run) 
Fatal Python error: Segmentation fault

Current thread 0x00007fdc2d71b740 (most recent call first):
  File "/b/s/w/ir/x/w/llvm_build/python3/lib/python3.11/site-packages/lldb/__init__.py", line 6750 in EvaluateExpression
  File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2547 in expect_expr
  File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/commands/expression/import-std-module/non-module-type-separation/TestNonModuleTypeSeparation.py", line 65 in test
  File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 148 in wrapper
  File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1804 in test_method
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/case.py", line 579 in _callTestMethod
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/case.py", line 623 in run
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/case.py", line 678 in __call__
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 122 in run
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 84 in __call__
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 122 in run
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 84 in __call__
  File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/runner.py", line 217 in run
  File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/dotest.py", line 1108 in run_suite
  File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/dotest.py", line 8 in <module>

Extension modules: lldb._lldb (total: 1)

--

https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/lldb-linux-x64/b8717163196427818881/overview

cc: @winner245 @llvm/pr-subscribers-libcxx @llvm/pr-subscribers-libcxxabi @llvm/pr-subscribers-lldb @llvm/issue-subscribers-lldb @mysterymath

[llvmbot]

@llvm/issue-subscribers-lldb

Author: None (gulfemsavrun)

We started seeing a segmentation fault while running some lldb tests after https://github.com//pull/134960. ``` UNRESOLVED: lldb-api :: commands/expression/import-std-module/list-dbg-info-content/TestDbgInfoContentListFromStdModule.py (159 of 2740) ******************** TEST 'lldb-api :: commands/expression/import-std-module/list-dbg-info-content/TestDbgInfoContentListFromStdModule.py' FAILED ******************** Script: -- /b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/bin/python3 /b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/b/s/w/ir/x/w/llvm_build/./lib --env LLVM_INCLUDE_DIR=/b/s/w/ir/x/w/llvm_build/include --env LLVM_TOOLS_DIR=/b/s/w/ir/x/w/llvm_build/./bin --arch x86_64 --build-dir /b/s/w/ir/x/w/llvm_build/lldb-test-build.noindex --lldb-module-cache-dir /b/s/w/ir/x/w/llvm_build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /b/s/w/ir/x/w/llvm_build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /b/s/w/ir/x/w/llvm_build/./bin/lldb --compiler /b/s/w/ir/x/w/cipd/clang/bin/clang --dsymutil /b/s/w/ir/x/w/llvm_build/./bin/dsymutil --make /b/s/w/ir/x/w/cipd/bin/make --llvm-tools-dir /b/s/w/ir/x/w/llvm_build/./bin --lldb-obj-root /b/s/w/ir/x/w/llvm_build/tools/lldb --lldb-libs-dir /b/s/w/ir/x/w/llvm_build/./lib --skip-category=pexpect /b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/commands/expression/import-std-module/list-dbg-info-content -p TestDbgInfoContentListFromStdModule.py --

Exit Code: -11

Current thread 0x00007f42d3c75740 (most recent call first):
File "/b/s/w/ir/x/w/llvm_build/python3/lib/python3.11/site-packages/lldb/init.py", line 6750 in EvaluateExpression
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2547 in expect_expr
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/commands/expression/import-std-module/vector-dbg-info-content/TestDbgInfoContentVectorFromStdModule.py", line 44 in test
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 148 in wrapper
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 148 in wrapper
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 148 in wrapper
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1804 in test_method
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/case.py", line 579 in _callTestMethod
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/case.py", line 623 in run
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/case.py", line 678 in call
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 122 in run
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 84 in call
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 122 in run
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/suite.py", line 84 in call
File "/b/s/w/ir/x/w/install-cpython-x86_64-linux-gnu/lib/python3.11/unittest/runner.py", line 217 in run
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/packages/Python/lldbsuite/test/dotest.py", line 1108 in run_suite
File "/b/s/w/ir/x/w/llvm-llvm-project/lldb/test/API/dotest.py", line 8 in <module>

Extension modules: lldb._lldb (total: 1)

https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/lldb-linux-x64/b8717163196427818881/overview

cc: @<!-- -->winner245 @<!-- -->llvm/pr-subscribers-libcxx @<!-- -->llvm/pr-subscribers-libcxxabi @<!-- -->llvm/pr-subscribers-lldb @<!-- -->llvm/issue-subscribers-lldb 
</details>

[shafik]

CC @winner245 @philnik777

[winner245]

Could you please share more details on how this issue is connected to #134960? From the information provided so far, I don't see how my patch could be the cause to the LLDB test failure. If there's more context or specific details related to #134960, it would be really helpful for me to investigate further. Of course, I don't mind reverting it if it turns out that my patch is the root cause.

[gulfemsavrun]

Could you please share more details on how this issue is connected to #134960? From the information provided so far, I don't see how my patch could be the cause to the LLDB test failure. If there's more context or specific details related to #134960, it would be really helpful for me to investigate further. Of course, I don't mind reverting it if it turns out that my patch is the root cause.

We are still trying to find out how they are connected, but we are positive that this change caused the issue because it is the only change in the blamelist:
https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/lldb-linux-x64/b8717163196427818881/blamelist

[DavidSpickett]

This is the test:
https://github.com/llvm/llvm-project/blob/main/lldb/test/API/commands/expression/import-std-module/non-module-type-separation/TestNonModuleTypeSeparation.py

This test requires that libc++ be available, so it's not running on Linaro's LLDB bots or the X86 Linux bot.

Apple is probably running it, and @Michael137 would be able to check that and maybe explain what the test is trying to do.

To get it running on Linux, you need to add libcxx to the runtimes:

cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DLLVM_LIT_ARGS=-v -DCMAKE_INSTALL_PREFIX=../install '-DLLVM_ENABLE_PROJECTS=lldb;clang;llvm;lld' -DLLVM_ENABLE_ASSERTIONS=True -DLLVM_USE_LINKER=lld -DLLDB_ENFORCE_STRICT_TEST_REQUIREMENTS=ON -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" ../llvm-project/llvm

Though when I did that, the test did not fail on AArch64 Linux.

@gulfemsavrun I see that the failure happened on a Fuchsia builder of some sort, but is it actually building on Fuschia? Please confirm the machine's setup for that build.

[mysterymath]

@gulfemsavrun I see that the failure happened on a Fuchsia builder of some sort, but is it actually building on Fuschia? Please confirm the machine's setup for that build.

This test is building and running on x86-64 Linux. We do build the Fuchsia toolchain hermetically (relying on as little from the host Linux as possible), so it often exercises the build configuration differently than other builders.

IIUC these tests exercise clang's expression evaluation engine for libc++ data structures, which has some sensitivity to libc++ headers. IIRC we've seen libc++ changes break these kinds of tests before. We also build libc++ statically, which is very different than most systems.