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Fix handling VAR data type #3169

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Merged
merged 1 commit into from
May 9, 2025
Merged

Fix handling VAR data type #3169

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20 changes: 18 additions & 2 deletions src/CLR/Core/Execution.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1971,10 +1971,26 @@ HRESULT CLR_RT_ExecutionEngine::InitializeLocals(

case DATATYPE_VAR:
{
// type-level generic parameter in a locals signature (e.g. 'T' inside a generic type)
CLR_INT8 genericParamPosition = *sig++;

methodDefInstance.assembly
->FindGenericParamAtTypeSpec(methodDefInstance, genericParamPosition, cls, dt);
// parse the locals-signature to extract that T
CLR_RT_SignatureParser parser;
parser.Initialize_MethodLocals(assembly, methodDef);
CLR_RT_SignatureParser::Element element;

// advance into the VAR entry
parser.Advance(element);

// walk forward to the Nth generic-parameter
for (int i = 0; i < genericParamPosition; i++)
{
parser.Advance(element);
}

// element.Class and element.DataType represent the T
cls = element.Class;
dt = element.DataType;

goto done;
}
Expand Down
59 changes: 25 additions & 34 deletions src/CLR/Core/TypeSystem.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -440,8 +440,6 @@ HRESULT CLR_RT_SignatureParser::Advance(Element &res)

NANOCLR_HEADER();

_ASSERTE(ParamCount > 0);

ParamCount--;

res.IsByRef = false;
Expand Down Expand Up @@ -988,13 +986,36 @@ bool CLR_RT_TypeDef_Instance::ResolveToken(
case DATATYPE_VAR:
{
CLR_RT_TypeDef_Index typeDef;
NanoCLRDataType dataType;
CLR_RT_SignatureParser::Element genericElement;

CLR_RT_SignatureParser varParser;
varParser.Initialize_TypeSpec(assm, ts);

caller->assembly->FindGenericParamAtTypeSpec(*caller, genericParamPosition, typeDef, dataType);
// advance once to consume the GENERICINST or VAR entry
varParser.Advance(genericElement);

// now walk forward genericParameterPosition steps to land on the actual
// argument in the signature stream.
for (CLR_INT8 i = 0; i <= genericParamPosition; i++)
{
if (FAILED(varParser.Advance(genericElement)))
{
return false;
}
}

// genericElement.Class now holds the TypeDef_Index of the T or U, etc.
typeDef = genericElement.Class;

// populate this instance from the resolved TypeDef
data = typeDef.data;
assembly = g_CLR_RT_TypeSystem.m_assemblies[typeDef.Assembly() - 1];
target = assembly->GetTypeDef(typeDef.Type());

#if defined(NANOCLR_INSTANCE_NAMES)
name = assembly->GetString(target->name);
#endif
return true;
}
break;

Expand Down Expand Up @@ -4455,36 +4476,6 @@ bool CLR_RT_Assembly::FindGenericParam(CLR_INDEX typeSpecIndex, CLR_RT_GenericPa
return false;
}

bool CLR_RT_Assembly::FindGenericParamAtTypeSpec(
CLR_RT_MethodDef_Instance md,
CLR_UINT32 genericParameterPosition,
CLR_RT_TypeDef_Index &index,
NanoCLRDataType &dataType)
{
NATIVE_PROFILE_CLR_CORE();

CLR_RT_SignatureParser parser;
parser.Initialize_TypeSpec(md.assembly, md.assembly->GetTypeSpec(md.genericType->TypeSpec()));

CLR_RT_SignatureParser::Element element;

// get type
parser.Advance(element);

for (uint32_t i = 0; i <= genericParameterPosition; i++)
{
if (FAILED(parser.Advance(element)))
{
return false;
}
}

index = element.Class;
dataType = element.DataType;

return true;
}

bool CLR_RT_Assembly::FindGenericParamAtMethodDef(
CLR_RT_MethodDef_Instance md,
CLR_UINT32 genericParameterPosition,
Expand Down
49 changes: 45 additions & 4 deletions src/CLR/Debugger/Debugger.cpp
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
//
//
// Copyright (c) .NET Foundation and Contributors
// Portions Copyright (c) Microsoft Corporation. All rights reserved.
// See LICENSE file in the project root for full license information.
Expand Down Expand Up @@ -2821,10 +2821,51 @@ bool CLR_DBG_Debugger::Debugging_Value_GetStack(WP_Message *msg)
// handle generic parameters
if (res.DataType == DATATYPE_VAR)
{
// Generic parameter in a generic TypeDef
md.assembly->FindGenericParamAtTypeSpec(md, res.GenericParamPosition, targetClass, targetDataType);
// type‐level generic parameter in a generic TypeDef: re‐parse the signature
CLR_RT_SignatureParser typeParser;

// isGenericInstance = true;
// for arguments, initialize over the method signature and skip the return slot
if (cmd->m_kind == CLR_DBG_Commands::Debugging_Value_GetStack::c_Argument)
{
typeParser.Initialize_MethodSignature(&md);

// skip the return value entry
iElement++;

// if there's an implicit 'this', adjust index
if (typeParser.Flags & PIMAGE_CEE_CS_CALLCONV_HASTHIS)
{
if (iElement == 0)
{
// requested the 'this' argument – invalid for a primitive
return false;
}
iElement--;
}
}
else
{
// for locals or eval‐stack, initialize over the locals signature
typeParser.Initialize_MethodLocals(md.assembly, md.target);
}

// advance to the requested argument/local
CLR_RT_SignatureParser::Element elem;
do
{
typeParser.Advance(elem);
} while (iElement-- > 0);

// now we've landed on a DATATYPE_VAR; walk to the Nth generic‐type parameter
typeParser.Advance(elem);
for (int i = 0; i < res.GenericParamPosition; i++)
{
parser.Advance(elem);
}

// this element.Class is the TypeDef_Index for 'T'
targetClass = elem.Class;
targetDataType = elem.DataType;
}
Comment on lines +2866 to 2869
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🛠️ Refactor suggestion

targetClass / targetDataType may remain uninitialised

When any of the above Advance operations fail the two out-parameters are left untouched yet later used to patch tmp.
Ensure they are initialised (e.g. to CLR_RT_TypeDef_Index::Invalid() / DATATYPE_VOID) right before the parsing starts, and only used when the parsing was successful.

else if (res.DataType == DATATYPE_MVAR)
{
Expand Down
5 changes: 0 additions & 5 deletions src/CLR/Include/nanoCLR_Runtime.h
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Expand Up @@ -1423,11 +1423,6 @@ struct CLR_RT_Assembly : public CLR_RT_HeapBlock_Node // EVENT HEAP - NO RELOCAT

bool FindTypeSpec(const CLR_PMETADATA sig, CLR_RT_TypeSpec_Index &index);

bool FindGenericParamAtTypeSpec(
CLR_RT_MethodDef_Instance md,
CLR_UINT32 genericParameterPosition,
CLR_RT_TypeDef_Index &index,
NanoCLRDataType &dataType);
bool FindGenericParamAtMethodDef(
CLR_RT_MethodDef_Instance md,
CLR_UINT32 genericParameterPosition,
Expand Down