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Generic attributes handling in CustomAttributeDecoder #72561

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merged 10 commits into from
Aug 9, 2022
Merged

Generic attributes handling in CustomAttributeDecoder #72561

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87eb054
Add handling of generic attributes to CustomAttributeDecoder
MichalStrehovsky Aug 16, 2021
c4b28bd
Update CustomAttributeDecoder.cs
MichalStrehovsky Aug 16, 2021
b8462c5
Update CustomAttributeDecoder.cs
MichalStrehovsky Aug 17, 2021
ae5977a
Update CustomAttributeDecoder.cs
MichalStrehovsky Aug 17, 2021
39f4b86
Add tests
buyaa-n Jul 20, 2022
bf813f3
Update tests to use reflection for testing all attributes
buyaa-n Aug 3, 2022
fa419f2
Merge conflict
buyaa-n Aug 3, 2022
1d8f656
Remove attribute row printing logic
buyaa-n Aug 3, 2022
807459c
Disable test on mono
buyaa-n Aug 8, 2022
613d6b3
Add back [ConditionalFact(typeof(PlatformDetection), nameof(PlatformD…
buyaa-n Aug 9, 2022
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Add handling of generic attributes to CustomAttributeDecoder 
If the attribute constructor refers to the generic T in its signature, we would throw `BadImageFormatException`. This adds handling by capturing the generic context and interpreting the signature variables when needed.
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@MichalStrehovsky @buyaa-n
MichalStrehovsky authored and buyaa-n committed Jul 19, 2022
commit 87eb0544f13a0cfff5fac0028e1ede94f82902ac
144 changes: 139 additions & 5 deletions ...stem.Reflection.Metadata/src/System/Reflection/Metadata/Ecma335/CustomAttributeDecoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ public CustomAttributeDecoder(ICustomAttributeTypeProvider<TType> provider, Meta
public CustomAttributeValue<TType> DecodeValue(EntityHandle constructor, BlobHandle value)
{
BlobHandle signature;
BlobHandle attributeOwningTypeSpec = default;
switch (constructor.Kind)
{
case HandleKind.MethodDefinition:
Expand All @@ -32,6 +33,13 @@ public CustomAttributeValue<TType> DecodeValue(EntityHandle constructor, BlobHan
case HandleKind.MemberReference:
MemberReference reference = _reader.GetMemberReference((MemberReferenceHandle)constructor);
signature = reference.Signature;

// If this is a generic attribute, we'll need its instantiation to decode the signatures
if (reference.Parent.Kind == HandleKind.TypeSpecification)
{
TypeSpecification genericOwner = _reader.GetTypeSpecification((TypeSpecificationHandle)reference.Parent);
attributeOwningTypeSpec = genericOwner.Signature;
}
break;

default:
Expand Down Expand Up @@ -60,12 +68,32 @@ public CustomAttributeValue<TType> DecodeValue(EntityHandle constructor, BlobHan
throw new BadImageFormatException();
}

ImmutableArray<CustomAttributeTypedArgument<TType>> fixedArguments = DecodeFixedArguments(ref signatureReader, ref valueReader, parameterCount);
BlobReader genericContextReader = default;
if (!attributeOwningTypeSpec.IsNil)
{
// If this is a generic attribute, grab the instantiation arguments so that we can
// interpret the constructor signature, should it refer to the generic context.
genericContextReader = _reader.GetBlobReader(attributeOwningTypeSpec);
if (genericContextReader.ReadSignatureTypeCode() == SignatureTypeCode.GenericTypeInstance)
{
int kind = genericContextReader.ReadCompressedInteger();
if (kind != (int)SignatureTypeKind.Class && kind != (int)SignatureTypeKind.ValueType)
{
throw new BadImageFormatException();
}

genericContextReader.ReadTypeHandle();

// At this point, the reader points to the "GenArgCount Type Type*" part of the signature.
}
}

ImmutableArray<CustomAttributeTypedArgument<TType>> fixedArguments = DecodeFixedArguments(ref signatureReader, ref valueReader, parameterCount, genericContextReader);
ImmutableArray<CustomAttributeNamedArgument<TType>> namedArguments = DecodeNamedArguments(ref valueReader);
return new CustomAttributeValue<TType>(fixedArguments, namedArguments);
}

private ImmutableArray<CustomAttributeTypedArgument<TType>> DecodeFixedArguments(ref BlobReader signatureReader, ref BlobReader valueReader, int count)
private ImmutableArray<CustomAttributeTypedArgument<TType>> DecodeFixedArguments(ref BlobReader signatureReader, ref BlobReader valueReader, int count, BlobReader genericContextReader)
{
if (count == 0)
{
Expand All @@ -76,7 +104,7 @@ private ImmutableArray<CustomAttributeTypedArgument<TType>> DecodeFixedArguments

for (int i = 0; i < count; i++)
{
ArgumentTypeInfo info = DecodeFixedArgumentType(ref signatureReader);
ArgumentTypeInfo info = DecodeFixedArgumentType(ref signatureReader, genericContextReader);
arguments.Add(DecodeArgument(ref valueReader, info));
}

Expand Down Expand Up @@ -124,7 +152,7 @@ private struct ArgumentTypeInfo
// better perf-wise, but even more important is that we can't actually reason about
// a method signature with opaque TType values without adding some unnecessary chatter
// with the provider.
private ArgumentTypeInfo DecodeFixedArgumentType(ref BlobReader signatureReader, bool isElementType = false)
private ArgumentTypeInfo DecodeFixedArgumentType(ref BlobReader signatureReader, BlobReader genericContextReader, bool isElementType = false)
{
SignatureTypeCode signatureTypeCode = signatureReader.ReadSignatureTypeCode();

Expand Down Expand Up @@ -170,12 +198,28 @@ private ArgumentTypeInfo DecodeFixedArgumentType(ref BlobReader signatureReader,
throw new BadImageFormatException();
}

var elementInfo = DecodeFixedArgumentType(ref signatureReader, isElementType: true);
var elementInfo = DecodeFixedArgumentType(ref signatureReader, genericContextReader, isElementType: true);
info.ElementType = elementInfo.Type;
info.ElementTypeCode = elementInfo.TypeCode;
info.Type = _provider.GetSZArrayType(info.ElementType);
break;

case SignatureTypeCode.GenericTypeParameter:
int parameterIndex = signatureReader.ReadCompressedInteger();
int numGenericParameters = genericContextReader.ReadCompressedInteger();
if (parameterIndex >= numGenericParameters)
{
throw new BadImageFormatException();
}

while (parameterIndex > 0)
{
SkipType(ref genericContextReader);
parameterIndex--;
}

return DecodeFixedArgumentType(ref genericContextReader, default, isElementType);

default:
throw new BadImageFormatException();
}
Expand Down Expand Up @@ -363,5 +407,95 @@ private TType GetTypeFromHandle(EntityHandle handle) =>
HandleKind.TypeReference => _provider.GetTypeFromReference(_reader, (TypeReferenceHandle)handle, 0),
_ => throw new BadImageFormatException(SR.NotTypeDefOrRefHandle),
};

private static void SkipType(ref BlobReader blobReader)
{
int typeCode = blobReader.ReadCompressedInteger();

switch (typeCode)
{
case (int)SignatureTypeCode.Boolean:
case (int)SignatureTypeCode.Char:
case (int)SignatureTypeCode.SByte:
case (int)SignatureTypeCode.Byte:
case (int)SignatureTypeCode.Int16:
case (int)SignatureTypeCode.UInt16:
case (int)SignatureTypeCode.Int32:
case (int)SignatureTypeCode.UInt32:
case (int)SignatureTypeCode.Int64:
case (int)SignatureTypeCode.UInt64:
case (int)SignatureTypeCode.Single:
case (int)SignatureTypeCode.Double:
case (int)SignatureTypeCode.IntPtr:
case (int)SignatureTypeCode.UIntPtr:
case (int)SignatureTypeCode.Object:
case (int)SignatureTypeCode.String:
case (int)SignatureTypeCode.Void:
case (int)SignatureTypeCode.TypedReference:
return;

case (int)SignatureTypeCode.Pointer:
case (int)SignatureTypeCode.ByReference:
case (int)SignatureTypeCode.Pinned:
case (int)SignatureTypeCode.SZArray:
SkipType(ref blobReader);
return;

case (int)SignatureTypeCode.FunctionPointer:
SignatureHeader header = blobReader.ReadSignatureHeader();
if (header.IsGeneric)
{
blobReader.ReadCompressedInteger(); // arity
}

int paramCount = blobReader.ReadCompressedInteger();
SkipType(ref blobReader);
for (int i = 0; i < paramCount; i++)
SkipType(ref blobReader);
return;

case (int)SignatureTypeCode.Array:
SkipType(ref blobReader);
blobReader.ReadCompressedInteger(); // rank
int boundsCount = blobReader.ReadCompressedInteger();
for (int i = 0; i < boundsCount; i++)
{
blobReader.ReadCompressedInteger();
}
int lowerBoundsCount = blobReader.ReadCompressedInteger();
for (int i = 0; i < lowerBoundsCount; i++)
{
blobReader.ReadCompressedSignedInteger();
}
return;

case (int)SignatureTypeCode.RequiredModifier:
case (int)SignatureTypeCode.OptionalModifier:
blobReader.ReadTypeHandle();
SkipType(ref blobReader);
return;

case (int)SignatureTypeCode.GenericTypeInstance:
SkipType(ref blobReader);
int count = blobReader.ReadCompressedInteger();
for (int i = 0; i < count; i++)
{
SkipType(ref blobReader);
}
return;

case (int)SignatureTypeCode.GenericTypeParameter:
blobReader.ReadCompressedInteger();
return;

case (int)SignatureTypeKind.Class:
case (int)SignatureTypeKind.ValueType:
SkipType(ref blobReader);
break;

default:
throw new BadImageFormatException();
}
}
}
}