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ControlFlowRegion.cs
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ControlFlowRegion.cs
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// Copyright (c) Microsoft. All Rights Reserved. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System.Collections.Immutable;
using System.Diagnostics;
using Microsoft.CodeAnalysis.Operations;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.FlowAnalysis
{
/// <summary>
/// Encapsulates information about regions of <see cref="BasicBlock"/>s in a <see cref="ControlFlowGraph"/>.
/// Regions can overlap, but never cross each other boundaries.
/// </summary>
public sealed class ControlFlowRegion
{
/// <summary>
/// Region's kind
/// </summary>
public ControlFlowRegionKind Kind { get; }
/// <summary>
/// Enclosing region. Null for <see cref="ControlFlowRegionKind.Root"/>
/// </summary>
public ControlFlowRegion EnclosingRegion { get; private set; }
/// <summary>
/// Target exception type for <see cref="ControlFlowRegionKind.Filter"/>, <see cref="ControlFlowRegionKind.Catch"/>,
/// <see cref="ControlFlowRegionKind.FilterAndHandler "/>
/// </summary>
public ITypeSymbol ExceptionType { get; }
/// <summary>
/// Ordinal (<see cref="BasicBlock.Ordinal"/>) of the first <see cref="BasicBlock"/> within the region.
/// </summary>
public int FirstBlockOrdinal { get; }
/// <summary>
/// Ordinal (<see cref="BasicBlock.Ordinal"/>) of the last <see cref="BasicBlock"/> within the region.
/// </summary>
public int LastBlockOrdinal { get; }
/// <summary>
/// Regions nested within this region.
/// </summary>
public ImmutableArray<ControlFlowRegion> NestedRegions { get; }
/// <summary>
/// Locals for which this region represent the life-time.
/// </summary>
public ImmutableArray<ILocalSymbol> Locals { get; }
/// <summary>
/// Local functions declared within the region.
/// </summary>
public ImmutableArray<IMethodSymbol> LocalFunctions { get; }
/// <summary>
/// Capture Ids used for intermediate results within the region.
/// </summary>
public ImmutableArray<CaptureId> CaptureIds { get; }
internal ControlFlowRegion(ControlFlowRegionKind kind, int firstBlockOrdinal, int lastBlockOrdinal,
ImmutableArray<ControlFlowRegion> nestedRegions,
ImmutableArray<ILocalSymbol> locals,
ImmutableArray<IMethodSymbol> methods,
ImmutableArray<CaptureId> captureIds,
ITypeSymbol exceptionType,
ControlFlowRegion enclosingRegion)
{
Debug.Assert(firstBlockOrdinal >= 0);
Debug.Assert(lastBlockOrdinal >= firstBlockOrdinal);
Kind = kind;
FirstBlockOrdinal = firstBlockOrdinal;
LastBlockOrdinal = lastBlockOrdinal;
ExceptionType = exceptionType;
Locals = locals.NullToEmpty();
LocalFunctions = methods.NullToEmpty();
CaptureIds = captureIds.NullToEmpty();
NestedRegions = nestedRegions.NullToEmpty();
EnclosingRegion = enclosingRegion;
foreach (ControlFlowRegion r in NestedRegions)
{
Debug.Assert(r.EnclosingRegion == null && r.Kind != ControlFlowRegionKind.Root);
r.EnclosingRegion = this;
}
#if DEBUG
int previousLast;
switch (kind)
{
case ControlFlowRegionKind.TryAndFinally:
case ControlFlowRegionKind.FilterAndHandler:
Debug.Assert(NestedRegions.Length == 2);
Debug.Assert(NestedRegions[0].Kind == (kind == ControlFlowRegionKind.TryAndFinally ? ControlFlowRegionKind.Try : ControlFlowRegionKind.Filter));
Debug.Assert(NestedRegions[1].Kind == (kind == ControlFlowRegionKind.TryAndFinally ? ControlFlowRegionKind.Finally : ControlFlowRegionKind.Catch));
Debug.Assert(NestedRegions[0].FirstBlockOrdinal == firstBlockOrdinal);
Debug.Assert(NestedRegions[1].LastBlockOrdinal == lastBlockOrdinal);
Debug.Assert(NestedRegions[0].LastBlockOrdinal + 1 == NestedRegions[1].FirstBlockOrdinal);
break;
case ControlFlowRegionKind.TryAndCatch:
Debug.Assert(NestedRegions.Length >= 2);
Debug.Assert(NestedRegions[0].Kind == ControlFlowRegionKind.Try);
Debug.Assert(NestedRegions[0].FirstBlockOrdinal == firstBlockOrdinal);
previousLast = NestedRegions[0].LastBlockOrdinal;
for (int i = 1; i < NestedRegions.Length; i++)
{
ControlFlowRegion r = NestedRegions[i];
Debug.Assert(previousLast + 1 == r.FirstBlockOrdinal);
previousLast = r.LastBlockOrdinal;
Debug.Assert(r.Kind == ControlFlowRegionKind.FilterAndHandler || r.Kind == ControlFlowRegionKind.Catch);
}
Debug.Assert(previousLast == lastBlockOrdinal);
break;
case ControlFlowRegionKind.Root:
case ControlFlowRegionKind.LocalLifetime:
case ControlFlowRegionKind.Try:
case ControlFlowRegionKind.Filter:
case ControlFlowRegionKind.Catch:
case ControlFlowRegionKind.Finally:
case ControlFlowRegionKind.StaticLocalInitializer:
case ControlFlowRegionKind.ErroneousBody:
previousLast = firstBlockOrdinal - 1;
foreach (ControlFlowRegion r in NestedRegions)
{
Debug.Assert(previousLast < r.FirstBlockOrdinal);
previousLast = r.LastBlockOrdinal;
}
Debug.Assert(previousLast <= lastBlockOrdinal);
break;
default:
throw ExceptionUtilities.UnexpectedValue(kind);
}
#endif
}
internal bool ContainsBlock(int destinationOrdinal)
{
return FirstBlockOrdinal <= destinationOrdinal && LastBlockOrdinal >= destinationOrdinal;
}
}
}