ML inliner and coroutine code crash

[pkasting]

The following code causes a fatal error when run with -std=c++20 -O -mllvm -enable-ml-inliner=release. See repro at https://godbolt.org/z/zze1o6d4a.

#include <coroutine>

void func();

struct S {
  struct promise_type {
    S get_return_object();
    std::suspend_never initial_suspend();
    std::suspend_always yield_value(int);
    std::suspend_never final_suspend() noexcept;
    void unhandled_exception();

    ~promise_type() { func(); }
  };
};

S get_s() {
  co_yield 0;
}

The output is:

error: Could not setup Inlining Advisor for the requested mode and/or options
fatal error: error in backend: Cannot select: intrinsic %llvm.coro.size
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: /opt/compiler-explorer/clang-trunk/bin/clang++ -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -std=c++20 -O -mllvm -enable-ml-inliner=release <source>
1.	<eof> parser at end of file
2.	Code generation
3.	Running pass 'Function Pass Manager' on module '<source>'.
4.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@_Z5get_sv'
 #0 0x000055a645ba338f llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x35ea38f)
 #1 0x000055a645ba13bc llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x35e83bc)
 #2 0x000055a645af3617 llvm::CrashRecoveryContext::HandleExit(int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x353a617)
 #3 0x000055a645b99022 llvm::sys::Process::Exit(int, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x35e0022)
 #4 0x000055a64343a51f (/opt/compiler-explorer/clang-trunk/bin/clang+++0xe8151f)
 #5 0x000055a645afc4ca llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x35434ca)
 #6 0x000055a646bb8af0 llvm::SelectionDAGISel::CannotYetSelect(llvm::SDNode*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x45ffaf0)
 #7 0x000055a646bbdd4d llvm::SelectionDAGISel::SelectCodeCommon(llvm::SDNode*, unsigned char const*, unsigned int) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4604d4d)
 #8 0x000055a6448517ea (anonymous namespace)::X86DAGToDAGISel::Select(llvm::SDNode*) X86ISelDAGToDAG.cpp:0:0
 #9 0x000055a646bb60e7 llvm::SelectionDAGISel::DoInstructionSelection() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x45fd0e7)
#10 0x000055a646bc2459 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4609459)
#11 0x000055a646bc523b llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x460c23b)
#12 0x000055a646bc7826 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (.part.0) SelectionDAGISel.cpp:0:0
#13 0x000055a64485b405 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) X86ISelDAGToDAG.cpp:0:0
#14 0x000055a645023040 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#15 0x000055a64553bcda llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x2f82cda)
#16 0x000055a64553be69 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x2f82e69)
#17 0x000055a64553ca50 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x2f83a50)
#18 0x000055a645e051e2 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x384c1e2)
#19 0x000055a646d07f32 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x474ef32)
#20 0x000055a6480c6119 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x5b0d119)
#21 0x000055a646d06e35 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x474de35)
#22 0x000055a6465f1001 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4038001)
#23 0x000055a6465732b3 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3fba2b3)
#24 0x000055a6466d1623 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x4118623)
#25 0x000055a64343bb4c cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xe82b4c)
#26 0x000055a6434370bf ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#27 0x000055a6463cdcfd void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#28 0x000055a645af3507 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x353a507)
#29 0x000055a6463cdf3c clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#30 0x000055a64639541c clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ddc41c)
#31 0x000055a646395e0d clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3ddce0d)
#32 0x000055a6463a043c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0x3de743c)
#33 0x000055a64343967f clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+++0xe8067f)
#34 0x000055a6433383c5 main (/opt/compiler-explorer/clang-trunk/bin/clang+++0xd7f3c5)
#35 0x00007f02b7df4083 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x24083)
#36 0x000055a64343329e _start (/opt/compiler-explorer/clang-trunk/bin/clang+++0xe7a29e)
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
Compiler returned: 70

[llvmbot]

@llvm/issue-subscribers-backend-x86

[aeubanks]

"parser at end of file" doesn't mean anything, the lines above it are what matter

error: Could not setup Inlining Advisor for the requested mode and/or options

is because godbolt's clang isn't compiled with ML inlining support. although I'm surprised it kept going after that.

fatal error: error in backend: Cannot select: intrinsic %llvm.coro.size

looks like the real issue. can you get a repro without the inliner flag?

[pkasting]

I can't repro on Win locally without that flag, and with that flag I always get the "error in backend" error. If you tell me how to build with ML inliner support on Windows (if such a thing exists), I can try to rebuild my LLVM checkout that way.

The original error on the Android bot is here, but uninformative: https://logs.chromium.org/logs/chromium/buildbucket/cr-buildbucket/8774566019004443201/+/u/compile__with_patch_/stdout

[aeubanks]

I don't believe it's supported on windows. This is something you'll probably need to repro on Linux. If there's a Chrome change I can try to repro the crash with I can try taking a look.

[pkasting]

When I tried just now on my Linux checkout with the Chromium clang and the testcase at the top of this bug, I got:

PLEASE submit a bug report to https://crbug.com in the Tools>LLVM component, run tools/clang/scripts/process_crashreports.py (only if inside Google) to upload crash related files, and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /usr/local/google/home/pkasting/src/trunk/src/third_party/llvm-build/Release+Asserts/bin/clang -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir a- -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name test.cc -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/local/google/home/pkasting/src/trunk/src -resource-dir /usr/local/google/home/pkasting/src/trunk/src/third_party/llvm-build/Release+Asserts/lib/clang/17 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/x86_64-linux-gnu/c++/12 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../include/c++/12/backward -internal-isystem /usr/local/google/home/pkasting/src/trunk/src/third_party/llvm-build/Release+Asserts/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/12/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O1 -std=c++20 -fdeprecated-macro -fdebug-compilation-dir=/usr/local/google/home/pkasting/src/trunk/src -ferror-limit 19 -fgnuc-version=4.2.1 -fno-implicit-modules -fcxx-exceptions -fexceptions -fcolor-diagnostics -mllvm -enable-ml-inliner=release -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/test-30e027.o -x c++ test.cc
1.	<eof> parser at end of file
2.	Optimizer
#0 0x0000558790cbebbf (/usr/local/google/home/pkasting/src/trunk/src/third_party/llvm-build/Release+Asserts/bin/clang+0x3ebebbf)
clang: error: unable to execute command: Segmentation fault
clang: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 17.0.0 (https://chromium.googlesource.com/a/external/github.com/llvm/llvm-project 0c545a441285a73e00b859dd52f1a85cb9eeeefc)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/google/home/pkasting/src/trunk/src/third_party/llvm-build/Release+Asserts/bin

Is that sufficient?

[aeubanks]

ah yes thanks

@mtrofin this looks like an ML inliner advisor issue

$ cat /tmp/b.ll
define void @_Z5get_sv() presplitcoroutine {
  %1 = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
  %2 = call ptr @llvm.coro.begin(token %1, ptr null)
  %3 = call token @llvm.coro.save(ptr null)
  %4 = call i8 @llvm.coro.suspend(token none, i1 false)
  call void @_ZN1S12promise_typeD2Ev()
  ret void
}

declare token @llvm.coro.id(i32, ptr readnone, ptr nocapture readonly, ptr)
declare ptr @llvm.coro.begin(token, ptr writeonly)
declare token @llvm.coro.save(ptr)
declare i8 @llvm.coro.suspend(token, i1)

declare void @__clang_call_terminate()

define void @_ZN1S12promise_typeD2Ev() personality ptr null {
  invoke void @_Z4funcv()
          to label %1 unwind label %2

1:                                                ; preds = %0
  ret void

2:                                                ; preds = %0
  %3 = landingpad { ptr, i32 }
          catch ptr null
  call void @__clang_call_terminate()
  unreachable
}

declare void @_Z4funcv()
$ opt -disable-output /tmp/b.ll -O2 -enable-ml-inliner=release
terminate called after throwing an instance of 'std::out_of_range'
  what():  map::at

probably something about coroutine lowering passes introducing functions that the ML inline advisor isn't expecting

[mtrofin]

Ack, I'll take a look. Thanks for the repro!

[zmodem]

@mtrofin, did you had a chance to look at this?

[mtrofin]

Not yet. Talked to @kazutakahirata to take a look, but didn't update the assignees (sorry).

[kazutakahirata]

Ack.

[mtrofin]

@zmodem to double-check, this is using the model that's part of the chromium's build of llvm, correct?

[zmodem]

@zmodem to double-check, this is using the model that's part of the chromium's build of llvm, correct?

Yes. (I didn't check, but I assume so; this came from https://crbug.com/1467960).

[aeubanks]

might be wrong, but I doubt the exact model will matter since these functions are so small and will probably get inlined given a reasonable model

[mtrofin]

#68263

@pkasting - I can't for some reason add you as a reviewer to the PR, so notifying this way.

[mtrofin]

PR #68263 should resolve this.