/// <summary>
/// Create a context for evaluating expressions within a method scope.
/// </summary>
/// <param name="previous">Previous context, if any, for possible re-use.</param>
/// <param name="metadataBlocks">Module metadata</param>
/// <param name="symReader"><see cref="ISymUnmanagedReader"/> for PDB associated with <paramref name="moduleVersionId"/></param>
/// <param name="moduleVersionId">Module containing method</param>
/// <param name="methodToken">Method metadata token</param>
/// <param name="methodVersion">Method version.</param>
/// <param name="ilOffset">IL offset of instruction pointer in method</param>
/// <param name="localSignatureToken">Method local signature token</param>
/// <returns>Evaluation context</returns>
internal static EvaluationContext CreateMethodContext(
CSharpMetadataContext previous,
ImmutableArray <MetadataBlock> metadataBlocks,
object symReader,
Guid moduleVersionId,
int methodToken,
int methodVersion,
int ilOffset,
int localSignatureToken)
{
Debug.Assert(MetadataTokens.Handle(methodToken).Kind == HandleKind.MethodDefinition);
var typedSymReader = (ISymUnmanagedReader)symReader;
var scopes = ArrayBuilder <ISymUnmanagedScope> .GetInstance();
typedSymReader.GetScopes(methodToken, methodVersion, ilOffset, IsLocalScopeEndInclusive, scopes);
var scope = scopes.GetMethodScope(methodToken, methodVersion);
// Re-use the previous compilation if possible.
CSharpCompilation compilation;
if (metadataBlocks.HaveNotChanged(previous))
{
// Re-use entire context if method scope has not changed.
var previousContext = previous.EvaluationContext;
if ((scope != null) && (previousContext != null) && scope.Equals(previousContext.MethodScope))
{
return(previousContext);
}
compilation = previous.Compilation;
}
else
{
compilation = metadataBlocks.ToCompilation();
}
var localNames = scopes.GetLocalNames();
var dynamicLocalMap = ImmutableDictionary <int, ImmutableArray <bool> > .Empty;
var dynamicLocalConstantMap = ImmutableDictionary <string, ImmutableArray <bool> > .Empty;
var inScopeHoistedLocalIndices = ImmutableSortedSet <int> .Empty;
var methodDebugInfo = default(MethodDebugInfo);
if (typedSymReader != null)
{
try
{
var cdi = typedSymReader.GetCustomDebugInfoBytes(methodToken, methodVersion);
if (cdi != null)
{
CustomDebugInfoReader.GetCSharpDynamicLocalInfo(
cdi,
methodToken,
methodVersion,
localNames.FirstOrDefault(),
out dynamicLocalMap,
out dynamicLocalConstantMap);
inScopeHoistedLocalIndices = CustomDebugInfoReader.GetCSharpInScopeHoistedLocalIndices(
cdi,
methodToken,
methodVersion,
ilOffset);
}
// TODO (acasey): switch on the type of typedSymReader and call the appropriate helper. (GH #702)
methodDebugInfo = typedSymReader.GetMethodDebugInfo(methodToken, methodVersion);
}
catch (InvalidOperationException)
{
// bad CDI, ignore
}
}
var methodHandle = (MethodDefinitionHandle)MetadataTokens.Handle(methodToken);
var currentFrame = compilation.GetMethod(moduleVersionId, methodHandle);
Debug.Assert((object)currentFrame != null);
var metadataDecoder = new MetadataDecoder((PEModuleSymbol)currentFrame.ContainingModule, currentFrame);
var localInfo = metadataDecoder.GetLocalInfo(localSignatureToken);
var localBuilder = ArrayBuilder <LocalSymbol> .GetInstance();
var sourceAssembly = compilation.SourceAssembly;
GetLocals(localBuilder, currentFrame, localNames, localInfo, dynamicLocalMap, sourceAssembly);
GetConstants(localBuilder, currentFrame, scopes.GetConstantSignatures(), metadataDecoder, dynamicLocalConstantMap, sourceAssembly);
scopes.Free();
var locals = localBuilder.ToImmutableAndFree();
return(new EvaluationContext(
metadataBlocks,
scope,
compilation,
metadataDecoder,
currentFrame,
locals,
inScopeHoistedLocalIndices,
methodDebugInfo));
}