public static ImmutableDictionary <CaptureId, FlowCaptureKind> CreateLValueFlowCaptures(ControlFlowGraph cfg)
{
// This method identifies flow capture reference operations that are target of an assignment
// and marks them as lvalue flow captures.
// Control flow graph can also contain flow captures
// that are r-value captures at some point and l-values captures at other point in
// the flow graph. Specifically, for an ICoalesceOperation a flow capture acts
// as both an r-value and l-value flow capture.
ImmutableDictionary <CaptureId, FlowCaptureKind> .Builder lvalueFlowCaptureIdBuilder = null;
var rvalueFlowCaptureIds = PooledHashSet <CaptureId> .GetInstance();
try
{
foreach (var flowCaptureReference in cfg.DescendantOperations <IFlowCaptureReferenceOperation>(OperationKind.FlowCaptureReference))
{
if (flowCaptureReference.Parent is IAssignmentOperation assignment &&
assignment.Target == flowCaptureReference ||
flowCaptureReference.IsInLeftOfDeconstructionAssignment(out _))
{
lvalueFlowCaptureIdBuilder ??= ImmutableDictionary.CreateBuilder <CaptureId, FlowCaptureKind>();
var captureKind = flowCaptureReference.Parent.IsAnyCompoundAssignment() || rvalueFlowCaptureIds.Contains(flowCaptureReference.Id)
? FlowCaptureKind.LValueAndRValueCapture
: FlowCaptureKind.LValueCapture;
lvalueFlowCaptureIdBuilder.Add(flowCaptureReference.Id, captureKind);
}
else
{
rvalueFlowCaptureIds.Add(flowCaptureReference.Id);
}
}
internal static IEnumerable <(BasicBlock predecessorBlock, BranchWithInfo branchWithInfo)> GetPredecessorsWithBranches(this BasicBlock basicBlock, ControlFlowGraph cfg)
{
foreach (ControlFlowBranch predecessorBranch in basicBlock.Predecessors)
{
var branchWithInfo = new BranchWithInfo(predecessorBranch);
if (!predecessorBranch.FinallyRegions.IsEmpty)
{
var lastFinally = predecessorBranch.FinallyRegions[^ 1];
public static BasicBlock GetExit(this ControlFlowGraph cfg) => cfg.Blocks.Single(b => b.Kind == BasicBlockKind.Exit);
public static IEnumerable <T> DescendantOperations <T>(this ControlFlowGraph cfg, OperationKind operationKind)
where T : IOperation
=> cfg.DescendantOperations().Where(d => d?.Kind == operationKind).Cast <T>();
public static IEnumerable <IOperation> DescendantOperations(this ControlFlowGraph cfg) => cfg.Blocks.SelectMany(b => b.DescendantOperations());
public static ImmutableDictionary <CaptureId, FlowCaptureKind> CreateLValueFlowCaptures(ControlFlowGraph cfg)
{
// This method identifies flow capture reference operations that are target of an assignment
// and marks them as lvalue flow captures.
// Note that currently the control flow graph does not contain flow captures
// that are r-value captures at some point and l-values captures at other point in
// the flow graph. The debug only asserts in this method ensure this invariant.
// If these asserts fire, we should adjust this algorithm.
ImmutableDictionary <CaptureId, FlowCaptureKind> .Builder lvalueFlowCaptureIdBuilder = null;
#if DEBUG
var rvalueFlowCaptureIds = new HashSet <CaptureId>();
#endif
foreach (var flowCaptureReference in cfg.DescendantOperations <IFlowCaptureReferenceOperation>(OperationKind.FlowCaptureReference))
{
if (flowCaptureReference.Parent is IAssignmentOperation assignment &&
assignment.Target == flowCaptureReference ||
flowCaptureReference.IsInLeftOfDeconstructionAssignment(out _))
{
lvalueFlowCaptureIdBuilder = lvalueFlowCaptureIdBuilder ?? ImmutableDictionary.CreateBuilder <CaptureId, FlowCaptureKind>();
var captureKind = flowCaptureReference.Parent is ICompoundAssignmentOperation ? FlowCaptureKind.LValueAndRValueCapture : FlowCaptureKind.LValueCapture;
lvalueFlowCaptureIdBuilder.Add(flowCaptureReference.Id, captureKind);
}
internal static IEnumerable <(BasicBlock predecessorBlock, BranchWithInfo branchWithInfo)> GetPredecessorsWithBranches(this BasicBlock basicBlock, ControlFlowGraph cfg)
{
foreach (ControlFlowBranch predecessorBranch in basicBlock.Predecessors)
{
var branchWithInfo = new BranchWithInfo(predecessorBranch);
if (predecessorBranch.FinallyRegions.Length > 0)
{
var lastFinally = predecessorBranch.FinallyRegions[predecessorBranch.FinallyRegions.Length - 1];
yield return(predecessorBlock : cfg.Blocks[lastFinally.LastBlockOrdinal], branchWithInfo);
}
else
{
yield return(predecessorBlock : predecessorBranch.Source, branchWithInfo);
}
}
}
public static IEnumerable <IOperation> DescendantOperations(this ControlFlowRegion controlFlowRegion, ControlFlowGraph cfg)
{
for (var i = controlFlowRegion.FirstBlockOrdinal; i <= controlFlowRegion.LastBlockOrdinal; i++)
{
var block = cfg.Blocks[i];
foreach (var operation in block.DescendantOperations())
{
yield return(operation);
}
}
}
