/// <summary>
/// Runs a fast, non-precise operation tree based analysis to compute symbol usage results
/// for symbol read/writes.
/// </summary>
public static SymbolUsageResult Run(IOperation rootOperation, ISymbol owningSymbol, CancellationToken cancellationToken)
{
AnalysisData analysisData = null;
using (analysisData = OperationTreeAnalysisData.Create(owningSymbol, AnalyzeLocalFunction))
{
var operations = SpecializedCollections.SingletonEnumerable(rootOperation);
Walker.AnalyzeOperationsAndUpdateData(operations, analysisData, cancellationToken);
return(analysisData.ToResult());
}
// Local functions.
BasicBlockAnalysisData AnalyzeLocalFunction(IMethodSymbol localFunction)
{
var localFunctionOperation = rootOperation.Descendants()
.FirstOrDefault(o => Equals((o as ILocalFunctionOperation)?.Symbol, localFunction));
// Can likely be null for broken code.
if (localFunctionOperation != null)
{
var operations = SpecializedCollections.SingletonEnumerable(localFunctionOperation);
Walker.AnalyzeOperationsAndUpdateData(operations, analysisData, cancellationToken);
}
return(analysisData.CurrentBlockAnalysisData);
}
}
public override BasicBlockAnalysisData AnalyzeBlock(BasicBlock basicBlock, CancellationToken cancellationToken)
{
BeforeBlockAnalysis();
Walker.AnalyzeOperationsAndUpdateData(basicBlock.Operations, _analysisData, cancellationToken);
AfterBlockAnalysis();
return(_analysisData.CurrentBlockAnalysisData);
// Local functions.
void BeforeBlockAnalysis()
{
// Initialize current block analysis data.
_analysisData.SetCurrentBlockAnalysisDataFrom(basicBlock, cancellationToken);
// At start of entry block, handle parameter definitions from method declaration.
if (basicBlock.Kind == BasicBlockKind.Entry)
{
_analysisData.SetAnalysisDataOnEntryBlockStart();
}
}
void AfterBlockAnalysis()
{
// If we are exiting the control flow graph, handle ref/out parameter definitions from method declaration.
if (basicBlock.FallThroughSuccessor?.Destination == null &&
basicBlock.ConditionalSuccessor?.Destination == null)
{
_analysisData.SetAnalysisDataOnMethodExit();
}
}
}
public override BasicBlockAnalysisData AnalyzeBlock(BasicBlock basicBlock, CancellationToken cancellationToken)
{
BeforeBlockAnalysis();
Walker.AnalyzeOperationsAndUpdateData(basicBlock.Operations, _analysisData, cancellationToken);
AfterBlockAnalysis();
return(_analysisData.CurrentBlockAnalysisData);
// Local functions.
void BeforeBlockAnalysis()
{
// Initialize current block analysis data.
_analysisData.SetCurrentBlockAnalysisDataFrom(basicBlock);
// At start of entry block, handle parameter definitions from method declaration.
if (basicBlock.Kind == BasicBlockKind.Entry)
{
_analysisData.SetAnalysisDataOnEntryBlockStart();
}
}
void AfterBlockAnalysis()
{
// At end of entry block, handle ref/out parameter definitions from method declaration.
if (basicBlock.Kind == BasicBlockKind.Exit)
{
_analysisData.SetAnalysisDataOnExitBlockEnd();
}
}
}
private BasicBlockAnalysisData AnalyzeBranch(
ControlFlowBranch branch,
BasicBlock basicBlock,
BasicBlockAnalysisData currentBlockAnalysisData,
CancellationToken cancellationToken
)
{
// Initialize current analysis data
_analysisData.SetCurrentBlockAnalysisDataFrom(currentBlockAnalysisData);
// Analyze the branch value
var operations = SpecializedCollections.SingletonEnumerable(basicBlock.BranchValue);
Walker.AnalyzeOperationsAndUpdateData(
_analysisData.OwningSymbol,
operations,
_analysisData,
cancellationToken
);
ProcessOutOfScopeLocals();
return(_analysisData.CurrentBlockAnalysisData);
// Local functions
void ProcessOutOfScopeLocals()
{
if (branch == null)
{
return;
}
if (
basicBlock.EnclosingRegion.Kind == ControlFlowRegionKind.Catch &&
!branch.FinallyRegions.IsEmpty
)
{
// Bail out for branches from the catch block
// as the locals are still accessible in the finally region.
return;
}
foreach (var region in branch.LeavingRegions)
{
foreach (var local in region.Locals)
{
_analysisData.CurrentBlockAnalysisData.Clear(local);
}
if (region.Kind == ControlFlowRegionKind.TryAndFinally)
{
// Locals defined in the outer regions of try/finally might be used in finally region.
break;
}
}
}
}
private BasicBlockAnalysisData AnalyzeBranch(
BasicBlock basicBlock,
BasicBlockAnalysisData currentBlockAnalysisData,
CancellationToken cancellationToken)
{
// Initialize current analysis data
_analysisData.SetCurrentBlockAnalysisDataFrom(currentBlockAnalysisData);
// Analyze the branch value
var operations = SpecializedCollections.SingletonEnumerable(basicBlock.BranchValue);
Walker.AnalyzeOperationsAndUpdateData(operations, _analysisData, cancellationToken);
return(_analysisData.CurrentBlockAnalysisData);
}