Crash in Inliner when using WebAssembly exception handling

[dschuff]

The attached program crashes in the inliner when wasm exception handling is enabled.
It was reduced with creduce, but I haven't attempted to reduce it manually yet.

class a;
class b {
public:
  a *operator->();
};
class c {
  void m_fn1();
  void e();
};
class f {
public:
  void g();
};
class a {
public:
  int h() { am.g(); return 0;}
  f am;
};
void c::e() {
  c *ao;
  bool ap = false;
  try {
    m_fn1();
    try {
      b d;
      int aq = d->h();
      if (aq)
        ap = true;
      m_fn1();
    } catch (int) {
    }
  } catch (...) {
    if (ap)
      ao = 0;
  }
}

command:

"/path/to/clang-15" "-cc1" "-triple" "wasm32-unknown-emscripten" "-emit-obj"  "-target-feature" "+exception-handling" "-mllvm" "-wasm-enable-eh"  "-O1"  "-std=gnu++17"  "-fcxx-exceptions" "-fexceptions" "-exception-model=wasm"  "-x" "c++" "repro.cpp"

It gives the following assertion failure:

clang-15: /s/llvm-upstream/llvm-project/llvm/lib/Transforms/Utils/InlineFunction.cpp:667: void HandleInlinedEHPad(llvm::InvokeInst *, llvm::BasicBlock *, llvm::ClonedCodeInfo &): Assertion `UnwindDest->getFirstNonPHI()->isEHPad() && "unexpected BasicBlock!"' failed.
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: /s/emr/install/bin/clang-15 -cc1 -triple wasm32-unknown-emscripten -emit-obj -target-feature +exception-handling -mllvm -wasm-enable-eh -O1 -std=gnu++17 -fcxx-exceptions -fexceptions -exception-model=wasm -x c++ repro.cpp
1.	<eof> parser at end of file
2.	Optimizer
 #0 0x00007fe0fc8b75c3 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMSupport.so.15git+0x23f5c3)
 #1 0x00007fe0fc8b527e llvm::sys::RunSignalHandlers() (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMSupport.so.15git+0x23d27e)
 #2 0x00007fe0fc8b7a8a SignalHandler(int) Signals.cpp:0:0
 #3 0x00007fe100878200 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12200)
 #4 0x00007fe0fc1568a1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:50:1
 #5 0x00007fe0fc140546 abort ./stdlib/abort.c:81:7
 #6 0x00007fe0fc14042f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8
 #7 0x00007fe0fc14042f _nl_load_domain ./intl/loadmsgcat.c:970:34
 #8 0x00007fe0fc14f222 (/lib/x86_64-linux-gnu/libc.so.6+0x31222)
 #9 0x00007fe0fe0213b4 llvm::InlineFunction(llvm::CallBase&, llvm::InlineFunctionInfo&, llvm::AAResults*, bool, llvm::Function*) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMTransformUtils.so.15git+0x1e63b4)
#10 0x00007fe0ff626061 llvm::InlinerPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMipo.so.15git+0x2c6061)
#11 0x00007fe0ff62e4ad llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::InlinerPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) Inliner.cpp:0:0
#12 0x00007fe0fdb0c221 llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMAnalysis.so.15git+0x36d221)
#13 0x00007fe0ff62e78d llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) Inliner.cpp:0:0
#14 0x00007fe0fdb0fe0b llvm::DevirtSCCRepeatedPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMAnalysis.so.15git+0x370e0b)
#15 0x00007fe0ff62ed4d llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::DevirtSCCRepeatedPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) Inliner.cpp:0:0
#16 0x00007fe0fdb0e57a llvm::ModuleToPostOrderCGSCCPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMAnalysis.so.15git+0x36f57a)
#17 0x00007fe0ff62eb0d llvm::detail::PassModel<llvm::Module, llvm::ModuleToPostOrderCGSCCPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) Inliner.cpp:0:0
#18 0x00007fe0fd55ef04 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMCore.so.15git+0x463f04)
#19 0x00007fe0ff628ca6 llvm::ModuleInlinerWrapperPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMipo.so.15git+0x2c8ca6)
#20 0x00007fe0fb799f8d llvm::detail::PassModel<llvm::Module, llvm::ModuleInlinerWrapperPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) PassBuilder.cpp:0:0
#21 0x00007fe0fd55ef04 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libLLVMCore.so.15git+0x463f04)
#22 0x00007fe1002f8de2 (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&) BackendUtil.cpp:0:0
#23 0x00007fe1002efee0 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libclangCodeGen.so.15git+0x285ee0)
#24 0x00007fe10069dc94 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) CodeGenAction.cpp:0:0
#25 0x00007fe0fa5f9cf3 clang::ParseAST(clang::Sema&, bool, bool) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/../lib/libclangParse.so.15git+0x66cf3)
#26 0x00007fe0fef180e0 clang::FrontendAction::Execute() (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libclangFrontend.so.15git+0x16b0e0)
#27 0x00007fe0fee888a8 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libclangFrontend.so.15git+0xdb8a8)
#28 0x00007fe1008629b3 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/usr/local/google/home/dschuff/s/emr/install/bin/../lib/libclangFrontendTool.so.15git+0x49b3)
#29 0x0000000000215150 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/s/emr/install/bin/clang-15+0x215150)
#30 0x0000000000213030 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) driver.cpp:0:0
#31 0x0000000000212dc5 main (/s/emr/install/bin/clang-15+0x212dc5)
#32 0x00007fe0fc1417fd __libc_start_main ./csu/../csu/libc-start.c:332:16
#33 0x000000000020ff3a _start (/s/emr/install/bin/clang-15+0x20ff3a)

[llvmbot]

@llvm/issue-subscribers-backend-webassembly

[aheejin]

@dschuff Is it from one of our partners, i.e., how time critical is this?

[dschuff]

As discussed offline: there's a workaround for the build that this test was derived from, which reduces the urgency. But it's not a great workaround (it's to disable opaque pointers), and it could stop working, so we shouldn't just let this drop for too long.