SILGen: Fix emission of keypath getter/setter when generic signature has only concrete parameters

[aschwaighofer]

We used to crash when creating a function type with a generic signature
that has only concrete parameters.

[aschwaighofer]

@jckarter Does this fix look right?

We used to assert on the test case:

Assertion failed: (!genericSig->areAllParamsConcrete() && "If all generic parameters are concrete, SILFunctionType should " "not have a generic signature at all"), function SILFunctionType, file /Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift/lib/AST/ASTContext.cpp, line 4010.
Stack dump:
0.	Program arguments: xctoolchain/usr/bin/swift -frontend -c -primary-file TestCrash.swift -target x86_64-apple-darwin18.5.0 -enable-objc-interop -color-diagnostics -module-name TestCrash -o /var/folders/99/mpw2m87x1nq5gplgn306y4gm0000gn/T/TestCrash-ecbdc5.o 
1.	While emitting property descriptor for 'crash' (at TestCrash.swift:5:29)
0  swift                    0x0000000105b9f815 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
1  swift                    0x0000000105b9ead5 llvm::sys::RunSignalHandlers() + 85
2  swift                    0x0000000105b9fdf8 SignalHandler(int) + 264
3  libsystem_platform.dylib 0x00007fff766e2b5d _sigtramp + 29
4  libsystem_platform.dylib 0x0000000000003ed8 _sigtramp + 2308051864
5  libsystem_c.dylib        0x00007fff7659c6a6 abort + 127
6  libsystem_c.dylib        0x00007fff7656520d basename_r + 0
7  swift                    0x0000000102de3c1d swift::SILFunctionType::SILFunctionType(swift::GenericSignature*, swift::SILFunctionType::ExtInfo, swift::SILCoroutineKind, swift::ParameterConvention, llvm::ArrayRef<swift::SILParameterInfo>, llvm::ArrayRef<swift::SILYieldInfo>, llvm::ArrayRef<swift::SILResultInfo>, llvm::Optional<swift::SILResultInfo>, swift::ASTContext const&, swift::RecursiveTypeProperties, llvm::Optional<swift::ProtocolConformanceRef>) + 2157
8  swift                    0x0000000102de42b0 swift::SILFunctionType::get(swift::GenericSignature*, swift::SILFunctionType::ExtInfo, swift::SILCoroutineKind, swift::ParameterConvention, llvm::ArrayRef<swift::SILParameterInfo>, llvm::ArrayRef<swift::SILYieldInfo>, llvm::ArrayRef<swift::SILResultInfo>, llvm::Optional<swift::SILResultInfo>, swift::ASTContext const&, llvm::Optional<swift::ProtocolConformanceRef>) + 1024
9  swift                    0x00000001024c602f getOrCreateKeyPathGetter(swift::Lowering::SILGenModule&, swift::SILLocation, swift::AbstractStorageDecl*, swift::SubstitutionMap, swift::GenericEnvironment*, swift::ResilienceExpansion, llvm::ArrayRef<std::__1::pair<swift::CanType, swift::SILType> >, swift::CanType, swift::CanType) + 1151
10 swift                    0x00000001024c47ec swift::Lowering::SILGenModule::emitKeyPathComponentForDecl(swift::SILLocation, swift::GenericEnvironment*, swift::ResilienceExpansion, unsigned int&, bool&, swift::SubstitutionMap, swift::AbstractStorageDecl*, llvm::ArrayRef<swift::ProtocolConformanceRef>, swift::CanType, bool) + 1500
11 swift                    0x000000010245a72d swift::Lowering::SILGenModule::tryEmitPropertyDescriptor(swift::AbstractStorageDecl*) + 797
 

[aschwaighofer]

@swift-ci Please test

[slavapestov]

Looks good. I have a PR open that removes that precondition and cleans up some other code but it changed optimizer behavior wrt inlining. I need to revisit it.

[swift-ci]

Build failed
Swift Test OS X Platform
Git Sha - d6c59cc

[aschwaighofer]

@swift-ci Please test os x