crash in tail call elimination of C++2a coroutines on MIPS

[llvmbot]

Bugzilla Link	48627
Version	11.0
OS	MacOS X
Attachments	the flattened code generated in the crash report
Reporter	LLVM Bugzilla Contributor
CC	@zygoloid,@rnk,@atanasyan

Extended Description

Here is a somewhat-whittled test case of a compiler crash trying to use coroutines on MIPS.

/usr/local/opt/llvm/bin/clang++ --sysroot debian-stretch-ish -target mips-linux-gnu -c -o test.o -std=c++2a -Os -fcoroutines-ts -nostdinc++ -isystem env/libcxx/include -isystem env/libcxxabi/include test.cpp

libcxx: 2076f539f410805ef88692b9c0ce0a0b882a7680
libcxxabi: a88633b46c401e6be38b93cf08660f137f86664d

$ /usr/local/opt/llvm/bin/clang++ --version
clang version 11.0.0
Target: x86_64-apple-darwin18.7.0
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin

#include <experimental/coroutine>

struct Task {
struct promise_type {
std::experimental::coroutine_handle<> code_;

    auto initial_suspend() noexcept {
        return std::experimental::suspend_always(); }
    auto final_suspend() noexcept {
        return std::experimental::suspend_always(); }

    auto get_return_object() noexcept {
        return Task(std::experimental::coroutine_handle<promise_type>::from_promise(*this));
    }

    void unhandled_exception() noexcept {}
    void return_void() noexcept {}
    void operator *() {}
};

std::experimental::coroutine_handle<promise_type> code_;

Task(std::experimental::coroutine_handle<promise_type> code) noexcept :
    code_(std::move(code)) {}

bool await_ready() noexcept {
    return !code_ || code_.done(); }

template <typename Promise_>
auto await_suspend(std::experimental::coroutine_handle<Promise_> code) noexcept {
    code_.promise().code_ = std::move(code);
    return code_;
}

auto await_resume() const {
    return *this->code_.promise();
}

};

Task f();
Task g() { co_await f(); }

fatal error: error in backend: failed to perform tail call elimination on a call site marked musttail
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0. Program arguments: /usr/local/opt/llvm/bin/clang++ --sysroot /Users/saurik/orchid/cli-shared/out-wrt/sysroot -target mips-linux-gnu -c -o test.o -std=c++2a -Os -fcoroutines-ts -nostdinc++ -isystem env/libcxx/include -isystem env/libcxxabi/include test.cpp

1.  <eof> parser at end of file
   

2.  Code generation
   

3.  Running pass 'Function Pass Manager' on module 'test.cpp'.
   

4.  Running pass 'MIPS DAG->DAG Pattern Instruction Selection' on function '@_Z1gv.resume'
   

0 libLLVM.dylib 0x00000001041da6c4 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 40
1 libLLVM.dylib 0x00000001041da141 llvm::sys::CleanupOnSignal(unsigned long) + 184
2 libLLVM.dylib 0x0000000104146b61 (anonymous namespace)::CrashRecoveryContextImpl::HandleCrash(int, unsigned long) + 97
3 libLLVM.dylib 0x0000000104146afe llvm::CrashRecoveryContext::HandleExit(int) + 14
4 libLLVM.dylib 0x00000001041d7927 llvm::sys::Process::Exit(int) + 35
5 clang++ 0x000000010195a73d LLVMErrorHandler(void*, std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator > const&, bool) + 180
6 libLLVM.dylib 0x000000010414f369 llvm::report_fatal_error(llvm::Twine const&, bool) + 254
7 libLLVM.dylib 0x000000010414f26b llvm::report_fatal_error(llvm::Twine const&, bool) + 0
8 libLLVM.dylib 0x000000010582cad6 llvm::MipsTargetLowering::LowerCall(llvm::TargetLowering::CallLoweringInfo&, llvm::SmallVectorImplllvm::SDValue&) const + 5702
9 libLLVM.dylib 0x000000010463fce0 llvm::TargetLowering::LowerCallTo(llvm::TargetLowering::CallLoweringInfo&) const + 3798
10 libLLVM.dylib 0x00000001046558de llvm::SelectionDAGBuilder::lowerInvokable(llvm::TargetLowering::CallLoweringInfo&, llvm::BasicBlock const*) + 386
11 libLLVM.dylib 0x00000001046452c7 llvm::SelectionDAGBuilder::LowerCallTo(llvm::CallBase const&, llvm::SDValue, bool, llvm::BasicBlock const*) + 1483
12 libLLVM.dylib 0x00000001046374e4 llvm::SelectionDAGBuilder::visitCall(llvm::CallInst const&) + 1170
13 libLLVM.dylib 0x000000010462ff87 llvm::SelectionDAGBuilder::visit(llvm::Instruction const&) + 113
14 libLLVM.dylib 0x00000001046964b5 llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true>, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true>, bool&) + 155
15 libLLVM.dylib 0x00000001046961d4 llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + 3686
16 libLLVM.dylib 0x00000001046949d4 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 1618
17 libLLVM.dylib 0x0000000105819d8c llvm::MipsDAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 32
18 libLLVM.dylib 0x00000001043e0cdb llvm::MachineFunctionPass::runOnFunction(llvm::Function&) + 239
19 libLLVM.dylib 0x00000001042a09a5 llvm::FPPassManager::runOnFunction(llvm::Function&) + 517
20 libLLVM.dylib 0x00000001042a4204 llvm::FPPassManager::runOnModule(llvm::Module&) + 52
21 libLLVM.dylib 0x00000001042a0e14 llvm::legacy::PassManagerImpl::run(llvm::Module&) + 668
22 libclang-cpp.dylib 0x00000001023d0e33 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::DataLayout const&, llvm::Module*, clang::BackendAction, std::__1::unique_ptr<llvm::raw_pwrite_stream, std::__1::default_deletellvm::raw_pwrite_stream >) + 10681
23 libclang-cpp.dylib 0x00000001025f8239 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) + 1041
24 libclang-cpp.dylib 0x0000000101a59e68 clang::ParseAST(clang::Sema&, bool, bool) + 507
25 libclang-cpp.dylib 0x0000000102af759b clang::FrontendAction::Execute() + 77
26 libclang-cpp.dylib 0x0000000102abf611 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 1287
27 libclang-cpp.dylib 0x0000000102b44afb clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1059
28 clang++ 0x000000010195a0b8 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) + 1880
29 clang++ 0x00000001019589c6 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&) + 270
30 libclang-cpp.dylib 0x00000001028bd1a1 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optionalllvm::StringRef >, std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, bool) const::$_1>(long) + 23
31 libLLVM.dylib 0x0000000104146adc llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) + 218
32 libclang-cpp.dylib 0x00000001028bc85f clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optionalllvm::StringRef >, std::__1::basic_string<char, std::__1::char_traits, std::__1::allocator >, bool) const + 233
33 libclang-cpp.dylib 0x000000010289d636 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&) const + 526
34 libclang-cpp.dylib 0x000000010289d825 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::__1::pair<int, clang::driver::Command const*> >&) const + 95
35 libclang-cpp.dylib 0x00000001028ac46a clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::__1::pair<int, clang::driver::Command const*> >&) + 210
36 clang++ 0x0000000101958202 main + 7204
37 libdyld.dylib 0x00007fff5de933d5 start + 1
clang-11: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 11.0.0
Target: mips-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin
clang-11: note: diagnostic msg:

---

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-11: note: diagnostic msg: /var/folders/h8/lhvqzq_d0rd1hqhvtvzrhqj00000gn/T/test-5e3bd1.cpp
clang-11: note: diagnostic msg: /var/folders/h8/lhvqzq_d0rd1hqhvtvzrhqj00000gn/T/test-5e3bd1.sh
clang-11: note: diagnostic msg: Crash backtrace is located in
clang-11: note: diagnostic msg: /Users/saurik/Library/Logs/DiagnosticReports/clang-11__.crash
clang-11: note: diagnostic msg: (choose the .crash file that corresponds to your crash)
clang-11: note: diagnostic msg:

---

[llvmbot]

assigned to @atanasyan

[rnk]

musttail support was only implemented on a handful of architectures (x86, arm, arm64). If it is being used for coroutines, someone needs to finish the job for other ISAs.

[Endilll]

Still crashing as of post-17 trunk in C++20 mode: https://godbolt.org/z/93bvc634a
#include <coroutine> doesn't work properly with this triple.
Reduced by C-Reduce:

namespace std {

template <class _Tp> struct __coroutine_traits_sfinae {
  using promise_type = typename _Tp::promise_type;
};
template <typename _Ret, typename... _Args>
struct coroutine_traits : public __coroutine_traits_sfinae<_Ret> {};
template <typename _Promise = void> class  coroutine_handle;
template <> class  coroutine_handle<> {
public:
    constexpr coroutine_handle() noexcept;
    constexpr void *address() const noexcept;

public:
    static coroutine_handle
  from_address(void *__addr) noexcept;
};
template <typename _Promise>
class  coroutine_handle : public coroutine_handle<> {};
struct suspend_always {
    bool await_ready() const noexcept;
  
   void await_suspend(coroutine_handle<>) const noexcept;
    void await_resume() const noexcept;
};

} // namespace std
struct Task {
  struct promise_type {
    auto initial_suspend() noexcept {
      return std::suspend_always();
    }
    auto final_suspend() noexcept {
      return std::suspend_always();
    }
    auto get_return_object() noexcept { return Task(); }
    void unhandled_exception() noexcept;
    void return_void() noexcept;
  };
  std::coroutine_handle<> code_;
  bool await_ready() noexcept;
  template <typename Promise_>
  auto await_suspend(std::coroutine_handle<Promise_> code) noexcept {
    return code_;
  }
  auto await_resume() const {}
};
Task f();
Task g() { co_await f(); }

CC @ChuanqiXu9

[llvmbot]

@llvm/issue-subscribers-coroutines

[llvmbot]

@llvm/issue-subscribers-backend-mips