Crossgen outerloop regression: Failures in GenericContextTest / GenericContextTestDefaultImp

[kg]

These tests both generate like 1000 lines of output when they run, success or failure, so I added some diagnostics code to the runtime and ran them.

runtime/src/coreclr/vm/genmeth.cpp

Line 786 in d450d9c

_ASSERTE(false);

is failing for what might be default interface methods in crossgen outerloop tests, and it reproduces locally.

Failed test: OutOfProcessTest::Loader/classloader/StaticVirtualMethods/GenericContext/GenericContextTest/GenericContextTest/GenericContextTest.cmd (Loader/classloader/StaticVirtualMethods/GenericContext/GenericContextTest/GenericContextTest/GenericContextTest.cmd) (Loader.Loader)
cp: target '/home/kate/Projects/dotnet-runtime-wasm/artifacts/tests/coreclr/linux.x64.Release/Tests/Core_Root/lib*.dylib': No such file or directory
pExactMT == NULL for pDefMD IFaceNonGeneric.NormalMethod
pExactMT == NULL for pDefMD IFaceNonGeneric.NormalMethod
pExactMT == NULL for pDefMD IFaceGeneric1<string>.NormalMethod pExactMT == NULL for pDefMD IFaceGeneric1.NormalMethod
pExactMT == NULL for pDefMD IFaceGeneric1<object>.NormalMethod pExactMT == NULL for pDefMD IFaceGeneric1.NormalMethod
pExactMT == NULL for pDefMD IFaceCuriouslyRecurringGeneric1<class GenericClass1<!0>>.NormalMethod
pExactMT == NULL for pDefMD IFaceCuriouslyRecurringGeneric1<valuetype GenericValuetype1<!0>>.NormalMethod
pExactMT == NULL for pDefMD IFaceNonGeneric.NormalMethod
pExactMT == NULL for pDefMD IFaceNonGeneric.NormalMethod
pExactMT == NULL for pDefMD IFaceGeneric1<string>.NormalMethod pExactMT == NULL for pDefMD IFaceGeneric1.NormalMethod
pExactMT == NULL for pDefMD IFaceGeneric1<object>.NormalMethod pExactMT == NULL for pDefMD IFaceGeneric1.NormalMethod
pExactMT == NULL for pDefMD IFaceCuriouslyRecurringGeneric1<class GenericClass1<!0>>.NormalMethod
pExactMT == NULL for pDefMD IFaceCuriouslyRecurringGeneric1<valuetype GenericValuetype1<!0>>.NormalMethod

Return code: 1

[kg]

Repro script (pass 'Checked'):

rm -rf ./artifacts
rm -rf ./artifacts/tests
rm -rf ./.dotnet
./build.sh Clr+Tools+Libs -c Release -rc $1 --os linux

./src/tests/build.sh $1 -priority1 -crossgen2 -p:LibrariesConfiguration=Release
PATH=/home/kate/Projects/dotnet-runtime-wasm/.dotnet/:$PATH RunCrossGen2=1 CompositeBuildMode=1 src/tests/run.sh $1

[kg]

This still reproduces but is kind of tricky to investigate because it seems like single method mode in R2R doesn't work for composite mode.

EDIT: With a fixed R2R single method mode you can debug using these arguments:
Z:\runtime\artifacts\bin\coreclr\windows.x64.Checked\crossgen2\crossgen2.dll @Z:\runtime\artifacts\tests\coreclr\windows.x64.Checked\Loader\classloader\StaticVirtualMethods\GenericContext\GenericContextTestDefaultImp\GenericContextTestDefaultImp\\composite-r2r.dll.rsp --singlemethodtypename "TestEntrypoint" --singlemethodname "Test_CreateDelegate_GenericOverReferenceType_ClassAGenericClass_NonGeneric_GenericOverObject_NormalMethod" --composite

EDIT 2: My best guess so far is that in that method in question, the constrained qualifier is being mishandled at some point from this:

	IL_0001: constrained. class [GenericContextCommonAndImplementationDefaultImp]GenericClass`1<object>
	IL_0007: ldftn void class [GenericContextCommonAndImplementationDefaultImp]IFaceGenericDefaultImp`1<object>::NormalMethod()
	IL_000d: newobj instance void [System.Runtime]System.Action::.ctor(object, native int)

When we reach MethodDesc::GetExactDeclaringType we get passed IFaceGenericDefaultImp`1[[System.Object, System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]]'s MethodTable, and the current MethodDesc is GenericClass`1[__Canon].IFaceGenericDefaultImp`1<object>.NormalMethod.

We call GetMethodTableMatchingParentClass(...) and it returns NULL . The pMT we pass to it is for GenericClass`1[__Canon]. The mismatch between a concrete System.Object generic argument for the interface and the canon argument for the class might be causing the 'matching' to fail?