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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Reflection.Metadata;
using Microsoft.CodeAnalysis.CodeGen;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Symbols;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.Emit
{
internal sealed class EncVariableSlotAllocator : VariableSlotAllocator
{
// symbols:
private readonly SymbolMatcher _symbolMap;
// syntax:
private readonly Func<SyntaxNode, SyntaxNode?>? _syntaxMap;
private readonly IMethodSymbolInternal _previousTopLevelMethod;
private readonly DebugId _methodId;
// locals:
private readonly IReadOnlyDictionary<EncLocalInfo, int> _previousLocalSlots;
private readonly ImmutableArray<EncLocalInfo> _previousLocals;
// previous state machine:
private readonly string? _stateMachineTypeName;
private readonly int _hoistedLocalSlotCount;
private readonly IReadOnlyDictionary<EncHoistedLocalInfo, int>? _hoistedLocalSlots;
private readonly int _awaiterCount;
private readonly IReadOnlyDictionary<Cci.ITypeReference, int>? _awaiterMap;
private readonly IReadOnlyDictionary<int, StateMachineState>? _stateMachineStateMap; // SyntaxOffset -> State Ordinal
private readonly StateMachineState? _firstUnusedDecreasingStateMachineState;
private readonly StateMachineState? _firstUnusedIncreasingStateMachineState;
// closures:
private readonly IReadOnlyDictionary<int, KeyValuePair<DebugId, int>>? _lambdaMap; // SyntaxOffset -> (Lambda Id, Closure Ordinal)
private readonly IReadOnlyDictionary<int, DebugId>? _closureMap; // SyntaxOffset -> Id
private readonly LambdaSyntaxFacts _lambdaSyntaxFacts;
public EncVariableSlotAllocator(
SymbolMatcher symbolMap,
Func<SyntaxNode, SyntaxNode?>? syntaxMap,
IMethodSymbolInternal previousTopLevelMethod,
DebugId methodId,
ImmutableArray<EncLocalInfo> previousLocals,
IReadOnlyDictionary<int, KeyValuePair<DebugId, int>>? lambdaMap,
IReadOnlyDictionary<int, DebugId>? closureMap,
string? stateMachineTypeName,
int hoistedLocalSlotCount,
IReadOnlyDictionary<EncHoistedLocalInfo, int>? hoistedLocalSlots,
int awaiterCount,
IReadOnlyDictionary<Cci.ITypeReference, int>? awaiterMap,
IReadOnlyDictionary<int, StateMachineState>? stateMachineStateMap,
StateMachineState? firstUnusedIncreasingStateMachineState,
StateMachineState? firstUnusedDecreasingStateMachineState,
LambdaSyntaxFacts lambdaSyntaxFacts)
{
Debug.Assert(!previousLocals.IsDefault);
_symbolMap = symbolMap;
_syntaxMap = syntaxMap;
_previousLocals = previousLocals;
_previousTopLevelMethod = previousTopLevelMethod;
_methodId = methodId;
_hoistedLocalSlots = hoistedLocalSlots;
_hoistedLocalSlotCount = hoistedLocalSlotCount;
_stateMachineTypeName = stateMachineTypeName;
_awaiterCount = awaiterCount;
_awaiterMap = awaiterMap;
_stateMachineStateMap = stateMachineStateMap;
_lambdaMap = lambdaMap;
_closureMap = closureMap;
_lambdaSyntaxFacts = lambdaSyntaxFacts;
_firstUnusedIncreasingStateMachineState = firstUnusedIncreasingStateMachineState;
_firstUnusedDecreasingStateMachineState = firstUnusedDecreasingStateMachineState;
// 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.IsUnused)
{
// Unrecognized or deleted local.
continue;
}
previousLocalInfoToSlot.Add(localInfo, slot);
}
_previousLocalSlots = previousLocalInfoToSlot;
}
public override DebugId? MethodId => _methodId;
private int CalculateSyntaxOffsetInPreviousMethod(SyntaxNode node)
{
// Note that syntax offset of a syntax node contained in a lambda body is calculated by the containing top-level method,
// not by the lambda method. The offset is thus relative to the top-level method body start. We can thus avoid mapping
// the current lambda symbol or body to the corresponding previous lambda symbol or body, which is non-trivial.
return _previousTopLevelMethod.CalculateLocalSyntaxOffset(_lambdaSyntaxFacts.GetDeclaratorPosition(node), node.SyntaxTree);
}
public override void AddPreviousLocals(ArrayBuilder<Cci.ILocalDefinition> builder)
{
builder.AddRange(_previousLocals.Select((info, index) =>
{
RoslynDebug.AssertNotNull(info.Signature);
return new SignatureOnlyLocalDefinition(info.Signature, index);
}));
}
private bool TryGetPreviousLocalId(SyntaxNode currentDeclarator, LocalDebugId currentId, out LocalDebugId previousId)
{
if (_syntaxMap == null)
{
// no syntax map
// => the source of the current method is the same as the source of the previous method
// => relative positions are the same
// => synthesized ids are the same
previousId = currentId;
return true;
}
SyntaxNode? previousDeclarator = _syntaxMap(currentDeclarator);
if (previousDeclarator == null)
{
previousId = default;
return false;
}
int syntaxOffset = CalculateSyntaxOffsetInPreviousMethod(previousDeclarator);
previousId = new LocalDebugId(syntaxOffset, currentId.Ordinal);
return true;
}
public override LocalDefinition? GetPreviousLocal(
Cci.ITypeReference currentType,
ILocalSymbolInternal currentLocalSymbol,
string? name,
SynthesizedLocalKind kind,
LocalDebugId id,
LocalVariableAttributes pdbAttributes,
LocalSlotConstraints constraints,
ImmutableArray<bool> dynamicTransformFlags,
ImmutableArray<string> tupleElementNames)
{
if (id.IsNone)
{
return null;
}
if (!TryGetPreviousLocalId(currentLocalSymbol.GetDeclaratorSyntax(), id, out LocalDebugId previousId))
{
return null;
}
var previousType = _symbolMap.MapReference(currentType);
if (previousType == null)
{
return null;
}
// TODO (bug #781309): Should report a warning if the type of the local has changed
// and the previous value will be dropped.
var localKey = new EncLocalInfo(new LocalSlotDebugInfo(kind, previousId), previousType, constraints, signature: null);
if (!_previousLocalSlots.TryGetValue(localKey, out int slot))
{
return null;
}
return new LocalDefinition(
currentLocalSymbol,
name,
currentType,
slot,
kind,
id,
pdbAttributes,
constraints,
dynamicTransformFlags,
tupleElementNames);
}
public override string? PreviousStateMachineTypeName => _stateMachineTypeName;
public override bool TryGetPreviousHoistedLocalSlotIndex(
SyntaxNode currentDeclarator,
Cci.ITypeReference currentType,
SynthesizedLocalKind synthesizedKind,
LocalDebugId currentId,
DiagnosticBag diagnostics,
out int slotIndex)
{
// The previous method was not a state machine (it is allowed to change non-state machine to a state machine):
if (_hoistedLocalSlots == null)
{
slotIndex = -1;
return false;
}
if (!TryGetPreviousLocalId(currentDeclarator, currentId, out LocalDebugId previousId))
{
slotIndex = -1;
return false;
}
var previousType = _symbolMap.MapReference(currentType);
if (previousType == null)
{
slotIndex = -1;
return false;
}
// TODO (bug #781309): Should report a warning if the type of the local has changed
// and the previous value will be dropped.
var localKey = new EncHoistedLocalInfo(new LocalSlotDebugInfo(synthesizedKind, previousId), previousType);
return _hoistedLocalSlots.TryGetValue(localKey, out slotIndex);
}
public override int PreviousHoistedLocalSlotCount => _hoistedLocalSlotCount;
public override int PreviousAwaiterSlotCount => _awaiterCount;
public override bool TryGetPreviousAwaiterSlotIndex(Cci.ITypeReference currentType, DiagnosticBag diagnostics, out int slotIndex)
{
// The previous method was not a state machine (it is allowed to change non-state machine to a state machine):
if (_awaiterMap == null)
{
slotIndex = -1;
return false;
}
var typeRef = _symbolMap.MapReference(currentType);
RoslynDebug.AssertNotNull(typeRef);
return _awaiterMap.TryGetValue(typeRef, out slotIndex);
}
private bool TryGetPreviousSyntaxOffset(SyntaxNode currentSyntax, out int previousSyntaxOffset)
{
// no syntax map
// => the source of the current method is the same as the source of the previous method
// => relative positions are the same
// => ids are the same
SyntaxNode? previousSyntax = _syntaxMap?.Invoke(currentSyntax);
if (previousSyntax == null)
{
previousSyntaxOffset = 0;
return false;
}
previousSyntaxOffset = CalculateSyntaxOffsetInPreviousMethod(previousSyntax);
return true;
}
private bool TryGetPreviousLambdaSyntaxOffset(SyntaxNode lambdaOrLambdaBodySyntax, bool isLambdaBody, out int previousSyntaxOffset)
{
// Syntax map contains mapping for lambdas, but not their bodies.
// Map the lambda first and then determine the corresponding body.
var currentLambdaSyntax = isLambdaBody
? _lambdaSyntaxFacts.GetLambda(lambdaOrLambdaBodySyntax)
: lambdaOrLambdaBodySyntax;
// no syntax map
// => the source of the current method is the same as the source of the previous method
// => relative positions are the same
// => ids are the same
SyntaxNode? previousLambdaSyntax = _syntaxMap?.Invoke(currentLambdaSyntax);
if (previousLambdaSyntax == null)
{
previousSyntaxOffset = 0;
return false;
}
SyntaxNode? previousSyntax;
if (isLambdaBody)
{
previousSyntax = _lambdaSyntaxFacts.TryGetCorrespondingLambdaBody(previousLambdaSyntax, lambdaOrLambdaBodySyntax);
if (previousSyntax == null)
{
previousSyntaxOffset = 0;
return false;
}
}
else
{
previousSyntax = previousLambdaSyntax;
}
previousSyntaxOffset = CalculateSyntaxOffsetInPreviousMethod(previousSyntax);
return true;
}
public override bool TryGetPreviousClosure(SyntaxNode scopeSyntax, out DebugId closureId)
{
if (_closureMap != null &&
TryGetPreviousSyntaxOffset(scopeSyntax, out int syntaxOffset) &&
_closureMap.TryGetValue(syntaxOffset, out closureId))
{
return true;
}
closureId = default;
return false;
}
public override bool TryGetPreviousLambda(SyntaxNode lambdaOrLambdaBodySyntax, bool isLambdaBody, out DebugId lambdaId)
{
if (_lambdaMap != null &&
TryGetPreviousLambdaSyntaxOffset(lambdaOrLambdaBodySyntax, isLambdaBody, out int syntaxOffset) &&
_lambdaMap.TryGetValue(syntaxOffset, out var idAndClosureOrdinal))
{
lambdaId = idAndClosureOrdinal.Key;
return true;
}
lambdaId = default;
return false;
}
public override StateMachineState? GetFirstUnusedStateMachineState(bool increasing)
=> increasing ? _firstUnusedIncreasingStateMachineState : _firstUnusedDecreasingStateMachineState;
public override bool TryGetPreviousStateMachineState(SyntaxNode syntax, out StateMachineState state)
{
if (_stateMachineStateMap != null &&
TryGetPreviousSyntaxOffset(syntax, out int syntaxOffset) &&
_stateMachineStateMap.TryGetValue(syntaxOffset, out state))
{
return true;
}
state = default;
return false;
}
}
}
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