[clang] [llvm] [llvm][clang] Allocate a new stack instead of spawning a new thread to get more stack space (PR #133173)

Tue Apr 15 12:14:06 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-linux-test-suite` running on `ppc64le-clang-test-suite` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/95/builds/12040

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
...

-- Compiler-RT supported architectures: powerpc64le
-- Generated Sanitizer SUPPORTED_TOOLS list on "Linux" is "asan;lsan;msan;tsan;ubsan"
-- sanitizer_common tests on "Linux" will run against "asan;lsan;msan;tsan;ubsan"
-- check-shadowcallstack does nothing.
-- Configuring done (8.7s)
-- Generating done (1.9s)
-- Build files have been written to: /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/runtimes/runtimes-bins
43.213 [69/498/655] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/ProgramStackTest.cpp.o
FAILED: unittests/Support/CMakeFiles/SupportTests.dir/ProgramStackTest.cpp.o 
ccache /usr/lib64/ccache/c++ -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/unittests/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/unittests/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/third-party/unittest/googletest/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/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/ProgramStackTest.cpp.o -MF unittests/Support/CMakeFiles/SupportTests.dir/ProgramStackTest.cpp.o.d -o unittests/Support/CMakeFiles/SupportTests.dir/ProgramStackTest.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/unittests/Support/ProgramStackTest.cpp
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/unittests/Support/ProgramStackTest.cpp: In member function ‘virtual void ProgramStackTest_runOnNewStack_Test::TestBody()’:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/unittests/Support/ProgramStackTest.cpp:33:55: error: call of overloaded ‘runOnNewStack(int, llvm::function_ref<void(int&)>, int&)’ is ambiguous
   runOnNewStack(0, function_ref<void(int &)>(func2), A);
                                                       ^
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/unittests/Support/ProgramStackTest.cpp:9:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/ProgramStack.h:48:3: note: candidate: ‘R llvm::runOnNewStack(unsigned int, llvm::function_ref<Ret(Params ...)>, Ts&& ...) [with R = void; Ts = {int&}]’
 R runOnNewStack(unsigned StackSize, function_ref<R(Ts...)> Fn, Ts &&...Args) {
   ^~~~~~~~~~~~~
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/ProgramStack.h:55:6: note: candidate: ‘void llvm::runOnNewStack(unsigned int, llvm::function_ref<void(Ts ...)>, Ts&& ...) [with Ts = {int&}]’
 void runOnNewStack(unsigned StackSize, function_ref<void(Ts...)> Fn,
      ^~~~~~~~~~~~~
43.221 [69/490/663] cd /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang/bindings/python && /home/buildbots/llvm-external-buildbots/cmake-3.31.2/bin/cmake -E env CLANG_NO_DEFAULT_CONFIG=1 CLANG_LIBRARY_PATH=/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/lib /home/buildbots/llvm-external-buildbots/workers/env/bin/python3.8 -m unittest discover
..............................................................................................................................................................
----------------------------------------------------------------------
Ran 158 tests in 7.373s

OK
44.977 [69/387/766] Building CXX object tools/clang/tools/extra/clangd/unittests/CMakeFiles/ClangdTests.dir/SymbolCollectorTests.cpp.o
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp: In member function ‘virtual void clang::clangd::{anonymous}::SymbolCollectorTest_SpelledReferences_Test::TestBody()’:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp:1148:8: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wdangling-else]
     if (!SpelledRanges.empty())
        ^
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp:1151:8: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wdangling-else]
     if (!ImplicitRanges.empty())
        ^
46.831 [69/354/799] Building CXX object tools/clang/tools/extra/clangd/unittests/CMakeFiles/ClangdTests.dir/support/TestTracer.cpp.o
46.877 [69/352/801] Building CXX object unittests/IR/CMakeFiles/IRTests.dir/ConstantFPRangeTest.cpp.o
47.011 [69/351/802] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/SourceMgrTest.cpp.o
47.085 [69/350/803] Building CXX object unittests/BinaryFormat/CMakeFiles/BinaryFormatTests.dir/MsgPackReaderTest.cpp.o
47.233 [69/349/804] Building CXX object unittests/Transforms/Utils/CMakeFiles/UtilsTests.dir/CodeLayoutTest.cpp.o
47.269 [69/348/805] Building CXX object unittests/Analysis/CMakeFiles/AnalysisTests.dir/AssumeBundleQueriesTest.cpp.o
47.281 [69/347/806] Building CXX object unittests/ExecutionEngine/JITLink/CMakeFiles/JITLinkTests.dir/X86_64Tests.cpp.o
47.325 [69/346/807] Building CXX object unittests/Analysis/CMakeFiles/AnalysisTests.dir/InlineCostTest.cpp.o
47.354 [69/345/808] Building CXX object unittests/ExecutionEngine/Orc/CMakeFiles/OrcJITTests.dir/OrcTestCommon.cpp.o
47.367 [69/344/809] Building CXX object unittests/Testing/Support/CMakeFiles/TestingSupportTests.dir/TempPathTest.cpp.o
47.563 [69/343/810] Building CXX object unittests/IR/CMakeFiles/IRTests.dir/BasicBlockTest.cpp.o
47.664 [69/342/811] Building CXX object unittests/ADT/CMakeFiles/ADTTests.dir/DenseSetTest.cpp.o

```

</details>

https://github.com/llvm/llvm-project/pull/133173