[clang] [crash] crashed during compilation of a module file

[mikomikotaishi]

A crash is occurring when trying to compile a program of mine, specifically the file Engine.cppm. Attached are the preprocessed source file (renamed to .cppm.txt from .cppm and run script). This started occurring today and it is not clear at what point inside my source file Engine.cppm is causing this.

Project is here, specific commit d4bfeca

This crash occurred with running make build, which internally runs

cmake -S . -B build -G Ninja
cmake --build build

Engine-88827d.cppm.txt
Engine-88827d.sh

Crash message and stack dump:

[25/32] Building CXX object src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o
FAILED: src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o src/openjuice/CMakeFiles/modules.dir/openjuice.engine.game.Engine.pcm 
/usr/bin/clang++ -DNDEBUG -DSFML_STATIC -DSTDLIB_EXTENSIONS -DSTDLIB_IMPLICIT_USING_CORE -DSTDLIB_USE_RESERVED_STD_IDENTIFIERS -I/home/utsuho/Projects/openJuice/include -I/home/utsuho/Projects/openJuice/build/_deps/boost-asio-src/include -I/home/utsuho/Projects/openJuice/build/_deps/boost-regex-src/include -I/home/utsuho/Projects/openJuice/build/_deps/boost-system-src/include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/core/../../include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/alloc/../../include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/std/../../include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/stdx/../../include -I/home/utsuho/Projects/openJuice/deps/discordpp/discordpp -I/home/utsuho/Projects/openJuice/build/_deps/sfml-src/include -isystem /home/utsuho/Projects/openJuice/build/_deps/ftxui-src/include -O3 -DNDEBUG -std=c++23 -O3 -stdlib=libstdc++ --gcc-toolchain=/usr -Wall -Wextra -Wpedantic -Wshadow -Wunused-parameter -Wconversion -Wsign-conversion -MD -MT src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o -MF src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o.d @src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o.modmap -o src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o -c /home/utsuho/Projects/openJuice/src/openjuice/engine/game/Engine.cppm
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: /usr/bin/clang++ @/tmp/response-81fdbf.txt
1.      <eof> parser at end of file
2.      Per-file LLVM IR generation
3.      /usr/lib64/gcc/x86_64-pc-linux-gnu/15.2.1/../../../../include/c++/15.2.1/bits/std_thread.h:207:5: Generating code for declaration 'std::thread::joinable'
 #0 0x00007faeb0580ada llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/lib/libLLVM.so.20.1+0x7780ada)
 #1 0x00007faeb047f592 (/usr/lib/libLLVM.so.20.1+0x767f592)
 #2 0x00007faea8644900 (/usr/lib/libc.so.6+0x44900)
 #3 0x00007faeb21e4785 clang::CodeGen::CodeGenFunction::EmitLValueForField(clang::CodeGen::LValue, clang::FieldDecl const*) (/usr/lib/libclang-cpp.so.20.1+0xfe4785)
 #4 0x00007faeb21e3ab2 clang::CodeGen::CodeGenFunction::EmitMemberExpr(clang::MemberExpr const*) (/usr/lib/libclang-cpp.so.20.1+0xfe3ab2)
 #5 0x00007faeb22726f5 clang::CodeGen::CodeGenFunction::EmitLValueHelper(clang::Expr const*, clang::CodeGen::KnownNonNull_t) (/usr/lib/libclang-cpp.so.20.1+0x10726f5)
 #6 0x00007faeb227346a clang::CodeGen::CodeGenFunction::EmitLValue(clang::Expr const*, clang::CodeGen::KnownNonNull_t) (/usr/lib/libclang-cpp.so.20.1+0x107346a)
 #7 0x00007faeb227b6a5 clang::CodeGen::CodeGenFunction::EmitCXXConstructorCall(clang::CXXConstructorDecl const*, clang::CXXCtorType, bool, bool, clang::CodeGen::AggValueSlot, clang::CXXConstructExpr const*) (/usr/lib/libclang-cpp.so.20.1+0x107b6a5)
 #8 0x00007faeb2548fd7 clang::CodeGen::CodeGenFunction::EmitCXXConstructExpr(clang::CXXConstructExpr const*, clang::CodeGen::AggValueSlot) (/usr/lib/libclang-cpp.so.20.1+0x1348fd7)
 #9 0x00007faeb254875c (/usr/lib/libclang-cpp.so.20.1+0x134875c)
#10 0x00007faeb2548366 clang::CodeGen::CodeGenFunction::EmitAggExpr(clang::Expr const*, clang::CodeGen::AggValueSlot) (/usr/lib/libclang-cpp.so.20.1+0x1348366)
#11 0x00007faeb22826bd clang::CodeGen::CodeGenFunction::EmitAnyExpr(clang::Expr const*, clang::CodeGen::AggValueSlot, bool) (/usr/lib/libclang-cpp.so.20.1+0x10826bd)
#12 0x00007faeb227da44 clang::CodeGen::CodeGenFunction::EmitCallArg(clang::CodeGen::CallArgList&, clang::Expr const*, clang::QualType) (/usr/lib/libclang-cpp.so.20.1+0x107da44)
#13 0x00007faeb227cdbb clang::CodeGen::CodeGenFunction::EmitCallArgs(clang::CodeGen::CallArgList&, clang::CodeGen::CodeGenFunction::PrototypeWrapper, llvm::iterator_range<clang::Stmt::CastIterator<clang::Expr, clang::Expr const* const, clang::Stmt const* const>>, clang::CodeGen::CodeGenFunction::AbstractCallee, unsigned int, clang::CodeGen::CodeGenFunction::EvaluationOrder) (/usr/lib/libclang-cpp.so.20.1+0x107cdbb)
#14 0x00007faeb227befe clang::CodeGen::CodeGenFunction::EmitCall(clang::QualType, clang::CodeGen::CGCallee const&, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::Value*, llvm::CallBase**, clang::CodeGen::CGFunctionInfo const**) (/usr/lib/libclang-cpp.so.20.1+0x107befe)
#15 0x00007faeb23d3924 clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::CallBase**) (/usr/lib/libclang-cpp.so.20.1+0x11d3924)
#16 0x00007faeb2282ab6 (/usr/lib/libclang-cpp.so.20.1+0x1082ab6)
#17 0x00007faeb36087eb (/usr/lib/libclang-cpp.so.20.1+0x24087eb)
#18 0x00007faeb2282790 clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/usr/lib/libclang-cpp.so.20.1+0x1082790)
#19 0x00007faeb244857c clang::CodeGen::CodeGenFunction::EvaluateExprAsBool(clang::Expr const*) (/usr/lib/libclang-cpp.so.20.1+0x124857c)
#20 0x00007faeb360d42f (/usr/lib/libclang-cpp.so.20.1+0x240d42f)
#21 0x00007faeb2282790 clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/usr/lib/libclang-cpp.so.20.1+0x1082790)
#22 0x00007faeb243d043 clang::CodeGen::CodeGenFunction::EmitReturnStmt(clang::ReturnStmt const&) (/usr/lib/libclang-cpp.so.20.1+0x123d043)
#23 0x00007faeb243e655 clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/usr/lib/libclang-cpp.so.20.1+0x123e655)
#24 0x00007faeb243e368 clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/usr/lib/libclang-cpp.so.20.1+0x123e368)
#25 0x00007faeb243b9cd clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/usr/lib/libclang-cpp.so.20.1+0x123b9cd)
#26 0x00007faeb220455a clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/libclang-cpp.so.20.1+0x100455a)
#27 0x00007faeb211c0cd clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/libclang-cpp.so.20.1+0xf1c0cd)
#28 0x00007faeb2432899 clang::CodeGen::CodeGenModule::EmitDeferred() (/usr/lib/libclang-cpp.so.20.1+0x1232899)
#29 0x00007faeb242b460 clang::CodeGen::CodeGenModule::Release() (/usr/lib/libclang-cpp.so.20.1+0x122b460)
#30 0x00007faeb242b3a0 (/usr/lib/libclang-cpp.so.20.1+0x122b3a0)
#31 0x00007faeb23e73c9 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/usr/lib/libclang-cpp.so.20.1+0x11e73c9)
#32 0x00007faeb219e143 clang::ParseAST(clang::Sema&, bool, bool) (/usr/lib/libclang-cpp.so.20.1+0xf9e143)
#33 0x00007faeb25c957f clang::FrontendAction::Execute() (/usr/lib/libclang-cpp.so.20.1+0x13c957f)
#34 0x00007faeb25c9134 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/lib/libclang-cpp.so.20.1+0x13c9134)
#35 0x00007faeb25c8b9e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/libclang-cpp.so.20.1+0x13c8b9e)
#36 0x000055cf4018b981 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/usr/bin/clang+++0x11981)
#37 0x000055cf4018adb4 (/usr/bin/clang+++0x10db4)
#38 0x000055cf40188ccd clang_main(int, char**, llvm::ToolContext const&) (/usr/bin/clang+++0xeccd)
#39 0x000055cf40188a8b main (/usr/bin/clang+++0xea8b)
#40 0x00007faea8627b8b (/usr/lib/libc.so.6+0x27b8b)
#41 0x00007faea8627c4b __libc_start_main (/usr/lib/libc.so.6+0x27c4b)
#42 0x000055cf4018d6a5 _start (/usr/bin/clang+++0x136a5)
clang++: error: unable to execute command: Segmentation fault (core dumped)
clang++: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 20.1.8
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang++: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang++: note: diagnostic msg: /tmp/Engine-88827d.cppm
clang++: note: diagnostic msg: /tmp/Engine-88827d.sh
clang++: note: diagnostic msg: 

********************
ninja: build stopped: subcommand failed.

[EugeneZelenko]

Could you please try 21 or main branch?

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: Miko (mikomikotaishi)

A crash is occurring when trying to compile a program of mine, specifically the file `Engine.cppm`. Attached are the preprocessed source file (renamed to `.cppm.txt` from `.cppm` and run script). This started occurring today and it is not clear at what point inside my source file `Engine.cppm` is causing this.

Project is here, specific commit d4bfeca

This crash occurred with running make build, which internally runs

cmake -S . -B build -G Ninja
cmake --build build

Engine-88827d.cppm.txt
Engine-88827d.sh

Crash message and stack dump:

[25/32] Building CXX object src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o
FAILED: src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o src/openjuice/CMakeFiles/modules.dir/openjuice.engine.game.Engine.pcm 
/usr/bin/clang++ -DNDEBUG -DSFML_STATIC -DSTDLIB_EXTENSIONS -DSTDLIB_IMPLICIT_USING_CORE -DSTDLIB_USE_RESERVED_STD_IDENTIFIERS -I/home/utsuho/Projects/openJuice/include -I/home/utsuho/Projects/openJuice/build/_deps/boost-asio-src/include -I/home/utsuho/Projects/openJuice/build/_deps/boost-regex-src/include -I/home/utsuho/Projects/openJuice/build/_deps/boost-system-src/include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/core/../../include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/alloc/../../include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/std/../../include -I/home/utsuho/Projects/openJuice/build/_deps/stdlib-src/src/stdx/../../include -I/home/utsuho/Projects/openJuice/deps/discordpp/discordpp -I/home/utsuho/Projects/openJuice/build/_deps/sfml-src/include -isystem /home/utsuho/Projects/openJuice/build/_deps/ftxui-src/include -O3 -DNDEBUG -std=c++23 -O3 -stdlib=libstdc++ --gcc-toolchain=/usr -Wall -Wextra -Wpedantic -Wshadow -Wunused-parameter -Wconversion -Wsign-conversion -MD -MT src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o -MF src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o.d @<!-- -->src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o.modmap -o src/openjuice/CMakeFiles/modules.dir/engine/game/Engine.cppm.o -c /home/utsuho/Projects/openJuice/src/openjuice/engine/game/Engine.cppm
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: /usr/bin/clang++ @/tmp/response-81fdbf.txt
1.      &lt;eof&gt; parser at end of file
2.      Per-file LLVM IR generation
3.      /usr/lib64/gcc/x86_64-pc-linux-gnu/15.2.1/../../../../include/c++/15.2.1/bits/std_thread.h:207:5: Generating code for declaration 'std::thread::joinable'
 #<!-- -->0 0x00007faeb0580ada llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/usr/lib/libLLVM.so.20.1+0x7780ada)
 #<!-- -->1 0x00007faeb047f592 (/usr/lib/libLLVM.so.20.1+0x767f592)
 #<!-- -->2 0x00007faea8644900 (/usr/lib/libc.so.6+0x44900)
 #<!-- -->3 0x00007faeb21e4785 clang::CodeGen::CodeGenFunction::EmitLValueForField(clang::CodeGen::LValue, clang::FieldDecl const*) (/usr/lib/libclang-cpp.so.20.1+0xfe4785)
 #<!-- -->4 0x00007faeb21e3ab2 clang::CodeGen::CodeGenFunction::EmitMemberExpr(clang::MemberExpr const*) (/usr/lib/libclang-cpp.so.20.1+0xfe3ab2)
 #<!-- -->5 0x00007faeb22726f5 clang::CodeGen::CodeGenFunction::EmitLValueHelper(clang::Expr const*, clang::CodeGen::KnownNonNull_t) (/usr/lib/libclang-cpp.so.20.1+0x10726f5)
 #<!-- -->6 0x00007faeb227346a clang::CodeGen::CodeGenFunction::EmitLValue(clang::Expr const*, clang::CodeGen::KnownNonNull_t) (/usr/lib/libclang-cpp.so.20.1+0x107346a)
 #<!-- -->7 0x00007faeb227b6a5 clang::CodeGen::CodeGenFunction::EmitCXXConstructorCall(clang::CXXConstructorDecl const*, clang::CXXCtorType, bool, bool, clang::CodeGen::AggValueSlot, clang::CXXConstructExpr const*) (/usr/lib/libclang-cpp.so.20.1+0x107b6a5)
 #<!-- -->8 0x00007faeb2548fd7 clang::CodeGen::CodeGenFunction::EmitCXXConstructExpr(clang::CXXConstructExpr const*, clang::CodeGen::AggValueSlot) (/usr/lib/libclang-cpp.so.20.1+0x1348fd7)
 #<!-- -->9 0x00007faeb254875c (/usr/lib/libclang-cpp.so.20.1+0x134875c)
#<!-- -->10 0x00007faeb2548366 clang::CodeGen::CodeGenFunction::EmitAggExpr(clang::Expr const*, clang::CodeGen::AggValueSlot) (/usr/lib/libclang-cpp.so.20.1+0x1348366)
#<!-- -->11 0x00007faeb22826bd clang::CodeGen::CodeGenFunction::EmitAnyExpr(clang::Expr const*, clang::CodeGen::AggValueSlot, bool) (/usr/lib/libclang-cpp.so.20.1+0x10826bd)
#<!-- -->12 0x00007faeb227da44 clang::CodeGen::CodeGenFunction::EmitCallArg(clang::CodeGen::CallArgList&amp;, clang::Expr const*, clang::QualType) (/usr/lib/libclang-cpp.so.20.1+0x107da44)
#<!-- -->13 0x00007faeb227cdbb clang::CodeGen::CodeGenFunction::EmitCallArgs(clang::CodeGen::CallArgList&amp;, clang::CodeGen::CodeGenFunction::PrototypeWrapper, llvm::iterator_range&lt;clang::Stmt::CastIterator&lt;clang::Expr, clang::Expr const* const, clang::Stmt const* const&gt;&gt;, clang::CodeGen::CodeGenFunction::AbstractCallee, unsigned int, clang::CodeGen::CodeGenFunction::EvaluationOrder) (/usr/lib/libclang-cpp.so.20.1+0x107cdbb)
#<!-- -->14 0x00007faeb227befe clang::CodeGen::CodeGenFunction::EmitCall(clang::QualType, clang::CodeGen::CGCallee const&amp;, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::Value*, llvm::CallBase**, clang::CodeGen::CGFunctionInfo const**) (/usr/lib/libclang-cpp.so.20.1+0x107befe)
#<!-- -->15 0x00007faeb23d3924 clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::CallBase**) (/usr/lib/libclang-cpp.so.20.1+0x11d3924)
#<!-- -->16 0x00007faeb2282ab6 (/usr/lib/libclang-cpp.so.20.1+0x1082ab6)
#<!-- -->17 0x00007faeb36087eb (/usr/lib/libclang-cpp.so.20.1+0x24087eb)
#<!-- -->18 0x00007faeb2282790 clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/usr/lib/libclang-cpp.so.20.1+0x1082790)
#<!-- -->19 0x00007faeb244857c clang::CodeGen::CodeGenFunction::EvaluateExprAsBool(clang::Expr const*) (/usr/lib/libclang-cpp.so.20.1+0x124857c)
#<!-- -->20 0x00007faeb360d42f (/usr/lib/libclang-cpp.so.20.1+0x240d42f)
#<!-- -->21 0x00007faeb2282790 clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/usr/lib/libclang-cpp.so.20.1+0x1082790)
#<!-- -->22 0x00007faeb243d043 clang::CodeGen::CodeGenFunction::EmitReturnStmt(clang::ReturnStmt const&amp;) (/usr/lib/libclang-cpp.so.20.1+0x123d043)
#<!-- -->23 0x00007faeb243e655 clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&amp;, bool, clang::CodeGen::AggValueSlot) (/usr/lib/libclang-cpp.so.20.1+0x123e655)
#<!-- -->24 0x00007faeb243e368 clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/usr/lib/libclang-cpp.so.20.1+0x123e368)
#<!-- -->25 0x00007faeb243b9cd clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&amp;) (/usr/lib/libclang-cpp.so.20.1+0x123b9cd)
#<!-- -->26 0x00007faeb220455a clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/libclang-cpp.so.20.1+0x100455a)
#<!-- -->27 0x00007faeb211c0cd clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/usr/lib/libclang-cpp.so.20.1+0xf1c0cd)
#<!-- -->28 0x00007faeb2432899 clang::CodeGen::CodeGenModule::EmitDeferred() (/usr/lib/libclang-cpp.so.20.1+0x1232899)
#<!-- -->29 0x00007faeb242b460 clang::CodeGen::CodeGenModule::Release() (/usr/lib/libclang-cpp.so.20.1+0x122b460)
#<!-- -->30 0x00007faeb242b3a0 (/usr/lib/libclang-cpp.so.20.1+0x122b3a0)
#<!-- -->31 0x00007faeb23e73c9 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&amp;) (/usr/lib/libclang-cpp.so.20.1+0x11e73c9)
#<!-- -->32 0x00007faeb219e143 clang::ParseAST(clang::Sema&amp;, bool, bool) (/usr/lib/libclang-cpp.so.20.1+0xf9e143)
#<!-- -->33 0x00007faeb25c957f clang::FrontendAction::Execute() (/usr/lib/libclang-cpp.so.20.1+0x13c957f)
#<!-- -->34 0x00007faeb25c9134 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/usr/lib/libclang-cpp.so.20.1+0x13c9134)
#<!-- -->35 0x00007faeb25c8b9e clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/lib/libclang-cpp.so.20.1+0x13c8b9e)
#<!-- -->36 0x000055cf4018b981 cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/usr/bin/clang+++0x11981)
#<!-- -->37 0x000055cf4018adb4 (/usr/bin/clang+++0x10db4)
#<!-- -->38 0x000055cf40188ccd clang_main(int, char**, llvm::ToolContext const&amp;) (/usr/bin/clang+++0xeccd)
#<!-- -->39 0x000055cf40188a8b main (/usr/bin/clang+++0xea8b)
#<!-- -->40 0x00007faea8627b8b (/usr/lib/libc.so.6+0x27b8b)
#<!-- -->41 0x00007faea8627c4b __libc_start_main (/usr/lib/libc.so.6+0x27c4b)
#<!-- -->42 0x000055cf4018d6a5 _start (/usr/bin/clang+++0x136a5)
clang++: error: unable to execute command: Segmentation fault (core dumped)
clang++: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 20.1.8
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang++: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang++: note: diagnostic msg: /tmp/Engine-88827d.cppm
clang++: note: diagnostic msg: /tmp/Engine-88827d.sh
clang++: note: diagnostic msg: 

********************
ninja: build stopped: subcommand failed.

[mikomikotaishi]

Could you please try 21 or main branch?

I'm just using the release provided by my package manager, 20.1.8. Should I manually clone and build version 21?

[jhuber6]

Could you please try 21 or main branch?

I'm just using the release provided by my package manager, 20.1.8. Should I manually clone and build version 21?

A smaller file that reproduces through https://godbolt.org/ on the clang (assertions trunk) compiler would be extremely helpful.

[mikomikotaishi]

A smaller file that reproduces through https://godbolt.org/ on the clang (assertions trunk) compiler would be extremely helpful.

Could you elaborate on what you mean? I'm not entirely sure what the problem is with my current file which is why I'm not sure how I would be able to reproduce the problem on Compiler Explorer.

[jhuber6]

Could you elaborate on what you mean? I'm not entirely sure what the problem is with my current file which is why I'm not sure how I would be able to reproduce the problem on Compiler Explorer.

There's a CMake project template on godbolt, but it'd be much easier if you could isolate the offending file and provide just that.

[mikomikotaishi]

There's a CMake project template on godbolt, but it'd be much easier if you could isolate the offending file and provide just that.

The specific file that this crashes on was Engine.cppm, I linked the project but here are the file contents (see here):

/**
 * @file Engine.cppm
 * @module openjuice.engine.game.Engine
 * @brief Engine implementation with threaded UI and game logic
 * 
 * This file contains the implementation of the game engine which manages
 * the main game loop and UI rendering in separate threads. It handles
 * thread synchronisation, state management, and the lifecycle of the game.
 */

module;

#include "Macros.hpp"

export module openjuice.engine.game.Engine;

import std;

import openjuice.engine.discord.DiscordManager;
import openjuice.engine.game.Game;
import openjuice.engine.util.Logging;
import openjuice.ui.UserInterface;
import openjuice.ui.cli.CommandLineInterface;
import openjuice.ui.tui.TextUserInterface;

#ifdef OPENJUICE_ALTERNATE_USING_SYNTAX
using std::concurrent::Thread;
using std::mem::{., SharedPointer, UniquePointer};
using std::sync::{AtomicBoolean, ConditionVariable, LockGuard, Mutex, UniqueLock};
using std::sys;
using std::time;
using std::time::SystemClock;
using std::time::temporal::{Milliseconds, Seconds};

using openjuice::engine::discord::DiscordManager;
using openjuice::engine::util::logging::*;
using openjuice::ui::cli::CommandLineInterface;
using openjuice::ui::tui::TextUserInterface;
using openjuice::ui::UserInterface;
#else
using std::concurrent::Thread;
using std::mem::SharedPointer;
using std::mem::UniquePointer;
using std::sync::AtomicBoolean;
using std::sync::ConditionVariable;
using std::sync::LockGuard;
using std::sync::Mutex;
using std::sync::UniqueLock;
using std::time::SystemClock;
using std::time::temporal::Milliseconds;
using std::time::temporal::Seconds;

namespace mem = std::mem;
namespace sys = std::sys;
namespace time = std::time;
namespace concurrent = std::concurrent;

using openjuice::engine::discord::DiscordManager;
using openjuice::ui::cli::CommandLineInterface;
using openjuice::ui::tui::TextUserInterface;
using openjuice::ui::UserInterface;

using namespace openjuice::engine::util::logging;
#endif

BEGIN_MODULE_NAMESPACE(openjuice::engine::game);

/**
 * @enum LaunchMode
 * @brief Launch modes for the game engine
 * 
 * Specifies which user interface should be used when running the game.
 */
export enum class LaunchMode: u8 {
    CLI, ///< Command Line Interface mode
    TUI  ///< Text User Interface mode
};

/**
 * @class Engine
 * @brief Main game engine class that manages game state and threading
 * 
 * The Engine class handles the core game loop, user interface, and thread
 * synchronisation. It uses separate threads for game logic and UI rendering
 * to ensure responsive gameplay even during computation-heavy operations.
 */
export class Engine {
private:
    static inline const Logger& LOGGER = Logger::getInstance(); ///< The logger instance.

    LaunchMode launchMode; ///< The selected user interface mode
    SharedPointer<Game> game; ///< The main game instance containing game state
    UniquePointer<DiscordManager> discordManager; ///< The manager for Discord integration.
    
    Mutex stateMutex; ///< Mutex for thread-safe access to game state
    ConditionVariable gameUpdateCV; ///< Condition variable for signaling game thread
    AtomicBoolean running{true}; ///< Flag indicating if the engine is running
    AtomicBoolean gamePaused{false}; ///< Flag indicating if the game is paused
    
    Thread gameThread; ///< Thread for running game logic
    Thread uiThread; ///< Thread for running UI logic
    
    /**
     * @brief Runs the actual game loop (all computational parts of the game)
     * 
     * This method executes in its own thread and handles all game state updates.
     * It uses condition variables for pause/resume functionality and minimizes
     * lock duration to ensure UI responsiveness.
     */
    void runGameLoop() {
        while (running.load()) {
            {
                UniqueLock<Mutex> lock(stateMutex);
                gameUpdateCV.wait(lock, [this]() -> bool { 
                    return !gamePaused.load() || !running.load(); 
                });
                
                if (!running.load()) {
                    break;
                }
            }
            
            {
                LockGuard<Mutex> lock(stateMutex);
                game->update(); 
            }
            
            concurrent::this_thread::sleep_for(Milliseconds(16));
        }
    }
    
    /**
     * @brief Runs the UI loop (separate from game calculations)
     * 
     * This method executes in its own thread and handles all UI rendering and
     * event processing. It creates the appropriate UI based on the selected
     * launch mode and synchronises with the game thread for state access.
     */
    void runUILoop() {
        UniquePointer<UserInterface> ui;
        switch (launchMode) {
            case LaunchMode::CLI:
                ui = mem::make_unique<CommandLineInterface>(game, stateMutex);
                break;
            case LaunchMode::TUI:
                ui = mem::make_unique<TextUserInterface>(game, stateMutex);
                break;
            default:
                sys::unreachable();
        }
        
        ui->init();
        
        while (running.load()) {
            ui->processEvents();
            
            if (ui->shouldExit()) {
                running.store(false);
                gameUpdateCV.notify_all();
                break;
            }
            
            {
                LockGuard<Mutex> lock(stateMutex);
                ui->render();
            }
            
            concurrent::this_thread::sleep_for(Milliseconds(33));
        }
    }

public:
    /**
     * @brief Constructs a new Engine object
     * 
     * @param mode The launch mode determining which UI to initialise
     */
    explicit Engine(LaunchMode mode): 
        launchMode{mode}, game{mem::make_shared<Game>()},
        discordManager{mem::make_unique<DiscordManager>()} {
        #ifndef NDEBUG
        LOGGER.log(LogLevel::DEBUG, "Creating Engine object");
        #endif
    }

    /**
     * @brief Destroy the Engine object
     */
    ~Engine() {
        #ifndef NDEBUG
        LOGGER.log(LogLevel::DEBUG, "Destroying Engine object");
        #endif

        if (running.load()) {
            stop();
            
            if (uiThread.joinable()) {
                uiThread.join();
            }
            if (gameThread.joinable()) {
                gameThread.join();
            }
        }

        #ifndef NDEBUG
        LOGGER.log(LogLevel::DEBUG, "Engine shutdown complete!");
        #endif
    }
    
    /**
     * @brief Initialises and starts the engine
     * 
     * Launches both game and UI threads and waits for them to complete.
     * The UI thread drives the application lifecycle; when it exits,
     * this method ensures the game thread is also terminated properly.
     */
    void init() {
        #ifndef NDEBUG
        LOGGER.log(LogLevel::DEBUG, "Initialising Engine");
        #endif

        if (discordManager->initialise()) {
            LOGGER.log(LogLevel::INFO, "Discord integration successfully initialised!");
            discordManager->setMenuActivity();
        } else {
            LOGGER.log(LogLevel::WARNING, "Discord integration unsuccessful!");
        }

        game->init();
        
        gameThread = Thread(&Engine::runGameLoop, this);
        uiThread = Thread(&Engine::runUILoop, this);
        
        uiThread.join();
        
        running.store(false);
        gameUpdateCV.notify_all();
        gameThread.join();
    }
    
    /**
     * @brief Pauses the game logic thread
     * 
     * Sets the paused flag to true, which causes the game thread to wait
     * on the condition variable until resumed.
     */
    void pause() noexcept {
        gamePaused.store(true);
    }
    
    /**
     * @brief Resumes the game logic thread if paused
     * 
     * Clears the paused flag and notifies the game thread to continue execution.
     */
    void resume() {
        gamePaused.store(false);
        gameUpdateCV.notify_all();
    }
    
    /**
     * @brief Signals all threads to stop and exit cleanly
     * 
     * Sets the running flag to false and notifies any waiting threads
     * to check their exit conditions.
     */
    void stop() {
        #ifndef NDEBUG
        LOGGER.log(LogLevel::DEBUG, "Stopping Engine");
        #endif
        
        running.store(false);
        gameUpdateCV.notify_all();
    }
    
    /**
     * @brief Get direct access to the game instance
     * 
     * @return SharedPointer<Game> Shared pointer to the game instance
     */
    [[nodiscard]]
    SharedPointer<Game> getGame() const noexcept {
        return game;
    }
};

END_MODULE_NAMESPACE();

Do note that I am using my own std module, rather than a libc++ std module, which possibly may an impact on this. However, I don't think that has to do with the compiler crashing when trying to compile that module. Either way, I have compiled that std module that I wrote several times in the past and this has not happened.

[mikomikotaishi]

Is building my project the way I described to diagnose the problem not a feasible solution?

[jhuber6]

Is building my project the way I described to diagnose the problem not a feasible solution?

Maintainer time is limited and the easier it is to reproduce and diagnose your bug the more likely it is to get fixed. Generally for clang crashes I've used things like https://github.com/marxin/cvise to get the offending source down to just a few lines in a single .cpp file that can be fed to godbolt with the appropriate compile flags.

[mikomikotaishi]

OK, I will look into this