using isKnownUniquelyReferenced seems to crash on C++ reference type

[wtholliday]

Description

Code that uses isKnownUniquelyReferenced on C++ reference type (exposed via C++ interop) seems to cause crash

Reproduction

My attempt to create a simple repro results in unexpected link error, which could be a related bug.

Working on repro case.

Stack dump

1.	Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4)
2.	Compiling with the current language version
3.	While emitting IR SIL function "@$s13SculpturaBase8VolStoreC7collectyyF".
 for 'collect()' (at /Users/holliday/Sculptura/SculpturaBase/Sources/SculpturaBase/VolStore.swift:51:12)
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  swift-frontend           0x0000000106757f3c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 56
1  swift-frontend           0x00000001067570f8 llvm::sys::RunSignalHandlers() + 112
2  swift-frontend           0x0000000106758544 SignalHandler(int) + 360
3  libsystem_platform.dylib 0x000000018cdaf584 _sigtramp + 56
4  swift-frontend           0x0000000101451d8c swift::irgen::IRGenFunction::emitIsUniqueCall(llvm::Value*, swift::ReferenceCounting, swift::SourceLoc, bool) + 872
5  swift-frontend           0x0000000101451d8c swift::irgen::IRGenFunction::emitIsUniqueCall(llvm::Value*, swift::ReferenceCounting, swift::SourceLoc, bool) + 872
6  swift-frontend           0x0000000101591c3c (anonymous namespace)::IRGenSILFunction::visitSILBasicBlock(swift::SILBasicBlock*) + 97852
7  swift-frontend           0x00000001015784fc swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 11556
8  swift-frontend           0x00000001013cc430 swift::irgen::IRGenerator::emitGlobalTopLevel(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>> const&) + 2472
9  swift-frontend           0x000000010152d498 swift::performIRGeneration(swift::ModuleDecl*, swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>>, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>, llvm::GlobalVariable**) + 2244
10 swift-frontend           0x000000010105c120 generateIR(swift::IRGenOptions const&, swift::TBDGenOptions const&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>>, swift::PrimarySpecificPaths const&, llvm::StringRef, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, llvm::GlobalVariable*&, llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>>>) + 260
11 swift-frontend           0x0000000101056294 performCompileStepsPostSILGen(swift::CompilerInstance&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule>>, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) + 1892
12 swift-frontend           0x0000000101055a18 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 2100
13 swift-frontend           0x0000000101059694 performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) + 1448
14 swift-frontend           0x00000001010576d0 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 4968
15 swift-frontend           0x0000000100fe6e8c swift::mainEntry(int, char const**) + 2612
16 dyld                     0x000000018c9f60e0 start + 2360

Expected behavior

Compiler doesn't crash

Environment

swift-driver version: 1.90.11.1 Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4)
Target: arm64-apple-macosx14.0

Additional information

No response

[wtholliday]

Am I correct in assuming that emitIsUniqueCall has to do with isKnownUniquelyReferenced?

[wtholliday]

I suppose that isKnownUniquelyReferenced can't work on something exposed from C++ because there is no way for Swift to actually get the reference count given this sort of interface:

struct SharedThing : public IntrusiveRefCounted<SharedThing> {

    static SharedThing* _Nonnull create();

    ~SharedThing();

private:
} SWIFT_SHARED_REFERENCE(retainSharedThing, releaseSharedThing);

void retainSharedThing(SharedThing * _Nonnull);
void releaseSharedThing(SharedThing * _Nonnull);