internal override bool TryGetPreviousLocals(
EmitBaseline baseline,
IMethodSymbol method,
out ImmutableArray <EncLocalInfo> previousLocals,
out GetPreviousLocalSlot getPreviousLocalSlot)
{
previousLocals = default(ImmutableArray <EncLocalInfo>);
getPreviousLocalSlot = NoPreviousLocalSlot;
MethodHandle handle;
if (!this.TryGetMethodHandle(baseline, (Cci.IMethodDefinition)method, out handle))
{
// Unrecognized method. Must have been added in the current compilation.
return(false);
}
MethodDefinitionEntry methodEntry;
if (!this.methodMap.TryGetValue(method, out methodEntry))
{
// Not part of changeset. No need to preserve locals.
return(false);
}
if (!methodEntry.PreserveLocalVariables)
{
// Not necessary to preserve locals.
return(false);
}
var previousMethod = methodEntry.PreviousMethod;
var methodIndex = (uint)MetadataTokens.GetRowNumber(handle);
SymbolMatcher map;
// Check if method has changed previously. If so, we already have a map.
if (baseline.LocalsForMethodsAddedOrChanged.TryGetValue(methodIndex, out previousLocals))
{
map = this.mapToPrevious;
}
else
{
// Method has not changed since initial generation. Generate a map
// using the local names provided with the initial metadata.
var localNames = baseline.LocalNames(methodIndex);
Debug.Assert(!localNames.IsDefault);
var localInfo = default(ImmutableArray <MetadataDecoder.LocalInfo>);
try
{
Debug.Assert(this.module.HasIL);
var methodBody = this.module.GetMethodBodyOrThrow(handle);
if (!methodBody.LocalSignature.IsNil)
{
var signatureHandle = this.module.MetadataReader.GetLocalSignature(methodBody.LocalSignature);
var signatureReader = this.module.GetMemoryReaderOrThrow(signatureHandle);
localInfo = this.metadataDecoder.DecodeLocalSignatureOrThrow(ref signatureReader);
}
else
{
localInfo = ImmutableArray <MetadataDecoder.LocalInfo> .Empty;
}
}
catch (UnsupportedSignatureContent)
{
}
catch (BadImageFormatException)
{
}
if (localInfo.IsDefault)
{
// TODO: Report error that metadata is not supported.
return(false);
}
else
{
// The signature may have more locals than names if trailing locals are unnamed.
// (Locals in the middle of the signature may be unnamed too but since localNames
// is indexed by slot, unnamed locals before the last named local will be represented
// as null values in the array.)
Debug.Assert(localInfo.Length >= localNames.Length);
previousLocals = GetLocalSlots(previousMethod, localNames, localInfo);
Debug.Assert(previousLocals.Length == localInfo.Length);
}
map = this.mapToMetadata;
}
// Find declarators in previous method syntax.
// The locals are indices into this list.
var previousDeclarators = LocalVariableDeclaratorsCollector.GetDeclarators(previousMethod);
// Create a map from declarator to declarator offset.
var previousDeclaratorToOffset = new Dictionary <SyntaxNode, int>();
for (int offset = 0; offset < previousDeclarators.Length; offset++)
{
previousDeclaratorToOffset.Add(previousDeclarators[offset], offset);
}
// Create a map from local info to slot.
var previousLocalInfoToSlot = new Dictionary <EncLocalInfo, int>();
for (int slot = 0; slot < previousLocals.Length; slot++)
{
var localInfo = previousLocals[slot];
Debug.Assert(!localInfo.IsDefault);
if (localInfo.IsInvalid)
{
// Unrecognized or deleted local.
continue;
}
previousLocalInfoToSlot.Add(localInfo, slot);
}
var syntaxMap = methodEntry.SyntaxMap;
if (syntaxMap == null)
{
// If there was no syntax map, the syntax structure has not changed,
// so we can map from current to previous syntax by declarator index.
Debug.Assert(methodEntry.PreserveLocalVariables);
// Create a map from declarator to declarator index.
var currentDeclarators = LocalVariableDeclaratorsCollector.GetDeclarators(method);
var currentDeclaratorToIndex = CreateDeclaratorToIndexMap(currentDeclarators);
syntaxMap = currentSyntax =>
{
var currentIndex = currentDeclaratorToIndex[(CSharpSyntaxNode)currentSyntax];
return(previousDeclarators[currentIndex]);
};
}
getPreviousLocalSlot = (object identity, Cci.ITypeReference typeRef, LocalSlotConstraints constraints) =>
{
var local = (LocalSymbol)identity;
var syntaxRefs = local.DeclaringSyntaxReferences;
Debug.Assert(!syntaxRefs.IsDefault);
if (!syntaxRefs.IsDefaultOrEmpty)
{
var currentSyntax = syntaxRefs[0].GetSyntax();
var previousSyntax = (CSharpSyntaxNode)syntaxMap(currentSyntax);
if (previousSyntax != null)
{
int offset;
if (previousDeclaratorToOffset.TryGetValue(previousSyntax, out offset))
{
var previousType = map.MapReference(typeRef);
if (previousType != null)
{
var localKey = new EncLocalInfo(offset, previousType, constraints, (int)local.SynthesizedLocalKind, signature: null);
int slot;
// Should report a warning if the type of the local has changed
// and the previous value will be dropped. (Bug #781309.)
if (previousLocalInfoToSlot.TryGetValue(localKey, out slot))
{
return(slot);
}
}
}
}
}
return(-1);
};
return(true);
}
internal override VariableSlotAllocator TryCreateVariableSlotAllocator(EmitBaseline baseline, IMethodSymbol method)
{
MethodHandle handle;
if (!this.TryGetMethodHandle(baseline, (Cci.IMethodDefinition)method, out handle))
{
// Unrecognized method. Must have been added in the current compilation.
return(null);
}
MethodDefinitionEntry methodEntry;
if (!this.methodMap.TryGetValue(method, out methodEntry))
{
// Not part of changeset. No need to preserve locals.
return(null);
}
if (!methodEntry.PreserveLocalVariables)
{
// Not necessary to preserve locals.
return(null);
}
CSharpSymbolMatcher symbolMap;
ImmutableArray <EncLocalInfo> previousLocals;
uint methodIndex = (uint)MetadataTokens.GetRowNumber(handle);
// Check if method has changed previously. If so, we already have a map.
if (baseline.LocalsForMethodsAddedOrChanged.TryGetValue(methodIndex, out previousLocals))
{
symbolMap = this.mapToPrevious;
}
else
{
// Method has not changed since initial generation. Generate a map
// using the local names provided with the initial metadata.
var localNames = baseline.LocalNames(handle);
Debug.Assert(!localNames.IsDefault);
ImmutableArray <MetadataDecoder.LocalInfo> localInfo;
if (!metadataDecoder.TryGetLocals(handle, out localInfo))
{
// TODO: Report error that metadata is not supported.
return(null);
}
// The signature may have more locals than names if trailing locals are unnamed.
// (Locals in the middle of the signature may be unnamed too but since localNames
// is indexed by slot, unnamed locals before the last named local will be represented
// as null values in the array.)
Debug.Assert(localInfo.Length >= localNames.Length);
previousLocals = GetLocalSlots(methodEntry.PreviousMethod, localNames, localInfo);
Debug.Assert(previousLocals.Length == localInfo.Length);
symbolMap = this.mapToMetadata;
}
// Find declarators in previous method syntax.
// The locals are indices into this list.
var previousDeclarators = LocalVariableDeclaratorsCollector.GetDeclarators(methodEntry.PreviousMethod);
var syntaxMap = methodEntry.SyntaxMap;
if (syntaxMap == null)
{
// If there was no syntax map, the syntax structure has not changed,
// so we can map from current to previous syntax by declarator index.
Debug.Assert(methodEntry.PreserveLocalVariables);
// Create a map from declarator to declarator index.
var currentDeclarators = LocalVariableDeclaratorsCollector.GetDeclarators(method);
var currentDeclaratorToIndex = CreateDeclaratorToIndexMap(currentDeclarators);
syntaxMap = currentSyntax =>
{
var currentIndex = currentDeclaratorToIndex[currentSyntax];
return(previousDeclarators[currentIndex]);
};
}
return(new EncVariableSlotAllocator(symbolMap, syntaxMap, previousDeclarators, previousLocals));
}