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.NET Decompiler with support for PDB generation, ReadyToRun, Metadata (&more) - cross-platform!
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ILSpy/ICSharpCode.Decompiler/IL/ILReader.cs

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// Copyright (c) 2014 Daniel Grunwald
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
#nullable enable
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Reflection.Metadata;
using System.Reflection.Metadata.Ecma335;
using System.Threading;
using ICSharpCode.Decompiler.Disassembler;
using ICSharpCode.Decompiler.TypeSystem;
using ICSharpCode.Decompiler.Util;
using ArrayType = ICSharpCode.Decompiler.TypeSystem.ArrayType;
using ByReferenceType = ICSharpCode.Decompiler.TypeSystem.ByReferenceType;
using PinnedType = ICSharpCode.Decompiler.TypeSystem.Implementation.PinnedType;
namespace ICSharpCode.Decompiler.IL
{
/// <summary>
/// Reads IL bytecodes and converts them into ILAst instructions.
/// </summary>
/// <remarks>
/// Instances of this class are not thread-safe. Use separate instances to decompile multiple members in parallel.
/// </remarks>
public class ILReader
{
/// <summary>
/// Represents a block of IL instructions.
/// </summary>
private sealed class ImportedBlock
{
// These members are immediately available after construction:
public readonly Block Block = new Block(BlockKind.ControlFlow);
public ImmutableStack<ILVariable> InputStack;
public int StartILOffset => Block.StartILOffset;
/// True if the import is in progress or completed.
public bool ImportStarted = false;
// When the block is imported, Block.Instructions is filled with the imported instructions
// and the following members are initialized:
public List<(ImportedBlock, ImmutableStack<ILVariable>)> OutgoingEdges = new();
public ImportedBlock(int offset, ImmutableStack<ILVariable> inputStack)
{
this.InputStack = inputStack;
this.Block.AddILRange(new Interval(offset, offset));
}
/// <summary>
/// Compares stack types and update InputStack if necessary.
/// Returns true if InputStack was updated, making a reimport necessary.
/// </summary>
public bool MergeStackTypes(ImmutableStack<ILVariable> newEdge)
{
var a = this.InputStack;
var b = newEdge;
bool changed = false;
while (!a.IsEmpty && !b.IsEmpty)
{
if (a.Peek().StackType < b.Peek().StackType)
{
changed = true;
}
a = a.Pop();
b = b.Pop();
}
if (!changed || !(a.IsEmpty && b.IsEmpty))
return false;
a = this.InputStack;
b = newEdge;
var output = new List<ILVariable>();
while (!a.IsEmpty && !b.IsEmpty)
{
if (a.Peek().StackType < b.Peek().StackType)
{
output.Add(b.Peek());
}
else
{
output.Add(a.Peek());
}
a = a.Pop();
b = b.Pop();
}
output.Reverse(); // restore correct stack order
this.InputStack = ImmutableStack.CreateRange(output);
this.ImportStarted = false;
return true;
}
internal void ResetForReimport()
{
this.Block.Instructions.Clear();
this.OutgoingEdges.Clear();
}
}
readonly ICompilation compilation;
readonly MetadataModule module;
readonly MetadataReader metadata;
public bool UseDebugSymbols { get; set; }
public bool UseRefLocalsForAccurateOrderOfEvaluation { get; set; }
public DebugInfo.IDebugInfoProvider? DebugInfo { get; set; }
public List<string> Warnings { get; } = new List<string>();
// List of candidate locations for sequence points. Includes empty il stack locations, any nop instructions, and the instruction following
// a call instruction.
public List<int> SequencePointCandidates { get; } = new List<int>();
/// <summary>
/// Creates a new ILReader instance.
/// </summary>
/// <param name="module">
/// The module used to resolve metadata tokens in the type system.
/// </param>
public ILReader(MetadataModule module)
{
if (module == null)
throw new ArgumentNullException(nameof(module));
this.module = module;
this.compilation = module.Compilation;
this.metadata = module.metadata;
}
// The members initialized with `null!` are initialized in the Init method.
GenericContext genericContext;
IMethod method = null!;
MethodBodyBlock body = null!;
StackType methodReturnStackType;
BlobReader reader;
ImmutableStack<ILVariable> currentStack = ImmutableStack<ILVariable>.Empty;
ImportedBlock? currentBlock;
List<ILInstruction> expressionStack = new List<ILInstruction>();
ILVariable[] parameterVariables = null!;
ILVariable[] localVariables = null!;
BitSet isBranchTarget = null!;
BlockContainer mainContainer = null!;
int currentInstructionStart;
Dictionary<int, ImportedBlock> blocksByOffset = new Dictionary<int, ImportedBlock>();
Queue<ImportedBlock> importQueue = new Queue<ImportedBlock>();
Dictionary<ExceptionRegion, ILVariable> variableByExceptionHandler = new Dictionary<ExceptionRegion, ILVariable>();
IEnumerable<ILVariable>? stackVariables;
void Init(MethodDefinitionHandle methodDefinitionHandle, MethodBodyBlock body, GenericContext genericContext)
{
if (body == null)
throw new ArgumentNullException(nameof(body));
if (methodDefinitionHandle.IsNil)
throw new ArgumentException("methodDefinitionHandle.IsNil");
this.method = module.GetDefinition(methodDefinitionHandle);
if (genericContext.ClassTypeParameters == null && genericContext.MethodTypeParameters == null)
{
// no generic context specified: use the method's own type parameters
genericContext = new GenericContext(method);
}
else
{
// generic context specified, so specialize the method for it:
this.method = this.method.Specialize(genericContext.ToSubstitution());
}
this.genericContext = genericContext;
this.body = body;
this.reader = body.GetILReader();
this.currentStack = ImmutableStack<ILVariable>.Empty;
this.expressionStack.Clear();
this.methodReturnStackType = method.ReturnType.GetStackType();
InitParameterVariables();
localVariables = InitLocalVariables();
foreach (var v in localVariables)
{
v.InitialValueIsInitialized = body.LocalVariablesInitialized;
v.UsesInitialValue = true;
}
this.mainContainer = new BlockContainer(expectedResultType: methodReturnStackType);
this.blocksByOffset.Clear();
this.importQueue.Clear();
this.isBranchTarget = new BitSet(reader.Length);
this.variableByExceptionHandler.Clear();
}
EntityHandle ReadAndDecodeMetadataToken()
{
int token = reader.ReadInt32();
if (token <= 0)
{
// SRM uses negative tokens as "virtual tokens" and can get confused
// if we manually create them.
// Row-IDs < 1 are always invalid.
throw new BadImageFormatException("Invalid metadata token");
}
return MetadataTokens.EntityHandle(token);
}
IType ReadAndDecodeTypeReference()
{
var typeReference = ReadAndDecodeMetadataToken();
return module.ResolveType(typeReference, genericContext);
}
IMethod ReadAndDecodeMethodReference()
{
var methodReference = ReadAndDecodeMetadataToken();
return module.ResolveMethod(methodReference, genericContext);
}
IField ReadAndDecodeFieldReference()
{
var fieldReference = ReadAndDecodeMetadataToken();
var f = module.ResolveEntity(fieldReference, genericContext) as IField;
if (f == null)
throw new BadImageFormatException("Invalid field token");
return f;
}
ILVariable[] InitLocalVariables()
{
if (body.LocalSignature.IsNil)
return Empty<ILVariable>.Array;
ImmutableArray<IType> variableTypes;
try
{
variableTypes = module.DecodeLocalSignature(body.LocalSignature, genericContext);
}
catch (BadImageFormatException ex)
{
Warnings.Add("Error decoding local variables: " + ex.Message);
variableTypes = ImmutableArray<IType>.Empty;
}
var localVariables = new ILVariable[variableTypes.Length];
foreach (var (index, type) in variableTypes.WithIndex())
{
localVariables[index] = CreateILVariable(index, type);
}
return localVariables;
}
void InitParameterVariables()
{
int popCount = method.Parameters.Count;
if (!method.IsStatic)
popCount++;
if (method.Parameters.LastOrDefault()?.Type == SpecialType.ArgList)
popCount--;
parameterVariables = new ILVariable[popCount];
int paramIndex = 0;
int offset = 0;
if (!method.IsStatic)
{
offset = 1;
IType declaringType = method.DeclaringType;
if (declaringType.IsUnbound())
{
// If method is a definition (and not specialized), the declaring type is also just a definition,
// and needs to be converted into a normally usable type.
declaringType = new ParameterizedType(declaringType, declaringType.TypeParameters);
}
ILVariable ilVar = CreateILVariable(-1, declaringType, "this");
ilVar.IsRefReadOnly = method.ThisIsRefReadOnly;
parameterVariables[paramIndex++] = ilVar;
}
while (paramIndex < parameterVariables.Length)
{
IParameter parameter = method.Parameters[paramIndex - offset];
ILVariable ilVar = CreateILVariable(paramIndex - offset, parameter.Type, parameter.Name);
ilVar.IsRefReadOnly = parameter.ReferenceKind is ReferenceKind.In or ReferenceKind.RefReadOnly;
parameterVariables[paramIndex] = ilVar;
paramIndex++;
}
Debug.Assert(paramIndex == parameterVariables.Length);
}
ILVariable CreateILVariable(int index, IType type)
{
VariableKind kind;
if (type.SkipModifiers() is PinnedType pinned)
{
kind = VariableKind.PinnedLocal;
type = pinned.ElementType;
}
else
{
kind = VariableKind.Local;
}
if (UseDebugSymbols && DebugInfo is not null &&
DebugInfo.TryGetExtraTypeInfo((MethodDefinitionHandle)method.MetadataToken, index, out var pdbExtraTypeInfo))
{
type = ApplyAttributeTypeVisitor.ApplyAttributesToType(type, compilation, module.TypeSystemOptions, pdbExtraTypeInfo);
}
ILVariable ilVar = new ILVariable(kind, type, index);
if (!UseDebugSymbols || DebugInfo == null || !DebugInfo.TryGetName((MethodDefinitionHandle)method.MetadataToken, index, out string name))
{
ilVar.Name = "V_" + index;
ilVar.HasGeneratedName = true;
}
else if (string.IsNullOrWhiteSpace(name))
{
ilVar.Name = "V_" + index;
ilVar.HasGeneratedName = true;
}
else
{
ilVar.Name = name;
}
return ilVar;
}
ILVariable CreateILVariable(int index, IType parameterType, string name)
{
Debug.Assert(!parameterType.IsUnbound());
ITypeDefinition? def = parameterType.GetDefinition();
if (def != null && index < 0 && def.IsReferenceType == false)
{
parameterType = new ByReferenceType(parameterType);
}
var ilVar = new ILVariable(VariableKind.Parameter, parameterType, index);
Debug.Assert(ilVar.StoreCount == 1); // count the initial store when the method is called with an argument
if (index < 0)
ilVar.Name = "this";
else if (string.IsNullOrWhiteSpace(name))
{
ilVar.Name = "P_" + index;
ilVar.HasGeneratedName = true;
}
else
ilVar.Name = name;
return ilVar;
}
/// <summary>
/// Warn when invalid IL is detected.
/// ILSpy should be able to handle invalid IL; but this method can be helpful for debugging the ILReader,
/// as this method should not get called when processing valid IL.
/// </summary>
void Warn(string message)
{
Warnings.Add(string.Format("IL_{0:x4}: {1}", currentInstructionStart, message));
}
/// <summary>
/// Check control flow edges for compatible stacks.
/// Returns union find data structure for unifying the different variables for the same stack slot.
/// Also inserts stack adjustments where necessary.
/// </summary>
UnionFind<ILVariable> CheckOutgoingEdges()
{
var unionFind = new UnionFind<ILVariable>();
foreach (var block in blocksByOffset.Values)
{
foreach (var (outgoing, stack) in block.OutgoingEdges)
{
var a = stack;
var b = outgoing.InputStack;
if (a.Count() != b.Count())
{
// Let's not try to merge mismatched stacks.
Warnings.Add($"IL_{block.Block.EndILOffset:x4}->IL{outgoing.StartILOffset:x4}: Incompatible stack heights: {a.Count()} vs {b.Count()}");
continue;
}
while (!a.IsEmpty && !b.IsEmpty)
{
var varA = a.Peek();
var varB = b.Peek();
if (varA.StackType == varB.StackType)
{
// The stack types match, so we can merge the variables.
unionFind.Merge(varA, varB);
}
else
{
Debug.Assert(varA.StackType < varB.StackType);
if (!IsValidTypeStackTypeMerge(varA.StackType, varB.StackType))
{
Warnings.Add($"IL_{block.Block.EndILOffset:x4}->IL{outgoing.StartILOffset:x4}: Incompatible stack types: {varA.StackType} vs {varB.StackType}");
}
InsertStackAdjustment(block.Block, varA, varB);
}
a = a.Pop();
b = b.Pop();
}
}
}
return unionFind;
}
/// <summary>
/// Inserts a copy from varA to varB (with conversion) at the end of <paramref name="block"/>.
/// If the block ends with a branching instruction, the copy is inserted before the branching instruction.
/// </summary>
private void InsertStackAdjustment(Block block, ILVariable varA, ILVariable varB)
{
int insertionPosition = block.Instructions.Count;
while (insertionPosition > 0 && block.Instructions[insertionPosition - 1].HasFlag(InstructionFlags.MayBranch))
{
// Branch instruction mustn't be initializing varA.
Debug.Assert(!block.Instructions[insertionPosition - 1].HasFlag(InstructionFlags.MayWriteLocals));
insertionPosition--;
}
ILInstruction value = new LdLoc(varA);
value = new Conv(value, varB.StackType.ToPrimitiveType(), false, Sign.Signed);
block.Instructions.Insert(insertionPosition, new StLoc(varB, value) { IsStackAdjustment = true });
}
private static bool IsValidTypeStackTypeMerge(StackType stackType1, StackType stackType2)
{
if (stackType1 == StackType.I && stackType2 == StackType.I4)
return true;
if (stackType1 == StackType.I4 && stackType2 == StackType.I)
return true;
if (stackType1 == StackType.F4 && stackType2 == StackType.F8)
return true;
if (stackType1 == StackType.F8 && stackType2 == StackType.F4)
return true;
// allow merging unknown type with any other type
return stackType1 == StackType.Unknown || stackType2 == StackType.Unknown;
}
/// <summary>
/// Stores the given stack for a branch to `offset`.
/// </summary>
ImportedBlock StoreStackForOffset(int offset, ImmutableStack<ILVariable> stack)
{
if (blocksByOffset.TryGetValue(offset, out var existing))
{
bool wasImported = existing.ImportStarted;
if (existing.MergeStackTypes(stack) && wasImported)
{
// If the stack changed, we need to re-import the block.
importQueue.Enqueue(existing);
}
return existing;
}
else
{
ImportedBlock newBlock = new ImportedBlock(offset, stack);
blocksByOffset.Add(offset, newBlock);
importQueue.Enqueue(newBlock);
return newBlock;
}
}
void ReadInstructions(CancellationToken cancellationToken)
{
reader.Reset();
StoreStackForOffset(0, ImmutableStack<ILVariable>.Empty);
if (reader.Length == 0)
{
blocksByOffset[0].Block.Instructions.Add(
new InvalidBranch("Empty body found. Decompiled assembly might be a reference assembly.")
);
stackVariables = Enumerable.Empty<ILVariable>();
return;
}
ILParser.SetBranchTargets(ref reader, isBranchTarget);
PrepareBranchTargetsAndStacksForExceptionHandlers();
// Import of IL byte codes:
while (importQueue.Count > 0)
{
cancellationToken.ThrowIfCancellationRequested();
ImportedBlock block = importQueue.Dequeue();
ReadBlock(block, cancellationToken);
}
EnsureExceptionHandlersHaveBlocks();
// Merge different variables for same stack slot:
var unionFind = CheckOutgoingEdges();
var visitor = new CollectStackVariablesVisitor(unionFind);
foreach (var block in blocksByOffset.Values)
{
block.Block.AcceptVisitor(visitor);
}
stackVariables = visitor.variables;
}
void ReadBlock(ImportedBlock block, CancellationToken cancellationToken)
{
Debug.Assert(!block.ImportStarted);
block.ResetForReimport();
block.ImportStarted = true;
reader.Offset = block.StartILOffset;
//Debug.WriteLine($"Import block at IL_{block.StartILOffset:x4} with inputs {string.Join(", ", block.InputStack.Select(v => v.StackType.ToString()))}");
currentBlock = block;
currentStack = block.InputStack;
// Read instructions until we reach the end of the block.
while (reader.RemainingBytes > 0)
{
cancellationToken.ThrowIfCancellationRequested();
int start = reader.Offset;
currentInstructionStart = start;
bool startedWithEmptyStack = CurrentStackIsEmpty();
DecodedInstruction decodedInstruction;
try
{
decodedInstruction = DecodeInstruction();
}
catch (BadImageFormatException ex)
{
decodedInstruction = new InvalidBranch(ex.Message);
}
var inst = decodedInstruction.Instruction;
if (inst.ResultType == StackType.Unknown && inst.OpCode != OpCode.InvalidBranch && inst.OpCode != OpCode.InvalidExpression)
Warn("Unknown result type (might be due to invalid IL or missing references)");
inst.CheckInvariant(ILPhase.InILReader);
int end = reader.Offset;
inst.AddILRange(new Interval(start, end));
if (!decodedInstruction.PushedOnExpressionStack)
{
// Flush to avoid re-ordering of side-effects
FlushExpressionStack();
block.Block.Instructions.Add(inst);
}
if ((!decodedInstruction.PushedOnExpressionStack && IsSequencePointInstruction(inst)) || startedWithEmptyStack)
{
this.SequencePointCandidates.Add(inst.StartILOffset);
}
if (inst.HasDirectFlag(InstructionFlags.EndPointUnreachable))
{
break; // end of block, don't parse following instructions if they are unreachable
}
else if (isBranchTarget[end] || inst.HasFlag(InstructionFlags.MayBranch))
{
break; // end of block (we'll create fall through)
}
}
// Finalize block
FlushExpressionStack();
block.Block.AddILRange(new Interval(block.StartILOffset, reader.Offset));
if (!block.Block.HasFlag(InstructionFlags.EndPointUnreachable))
{
// create fall through branch
ILInstruction branch;
if (reader.RemainingBytes > 0)
{
MarkBranchTarget(reader.Offset, isFallThrough: true);
branch = new Branch(reader.Offset);
}
else
{
branch = new InvalidBranch("End of method reached without returning.");
}
if (block.Block.Instructions.LastOrDefault() is SwitchInstruction switchInst && switchInst.Sections.Last().Body.MatchNop())
{
// Instead of putting the default branch after the switch instruction
switchInst.Sections.Last().Body = branch;
Debug.Assert(switchInst.HasFlag(InstructionFlags.EndPointUnreachable));
}
else
{
block.Block.Instructions.Add(branch);
}
}
}
private bool CurrentStackIsEmpty()
{
return currentStack.IsEmpty && expressionStack.Count == 0;
}
private void PrepareBranchTargetsAndStacksForExceptionHandlers()
{
// Fill isBranchTarget and branchStackDict based on exception handlers
foreach (var eh in body.ExceptionRegions)
{
// Always mark the start of the try block as a "branch target".
// We need to ensure that we put a block boundary there.
isBranchTarget[eh.TryOffset] = true;
ImmutableStack<ILVariable> ehStack;
if (eh.Kind == ExceptionRegionKind.Catch)
{
var catchType = module.ResolveType(eh.CatchType, genericContext);
var v = new ILVariable(VariableKind.ExceptionStackSlot, catchType, eh.HandlerOffset) {
Name = "E_" + eh.HandlerOffset,
HasGeneratedName = true
};
variableByExceptionHandler.Add(eh, v);
ehStack = ImmutableStack.Create(v);
}
else if (eh.Kind == ExceptionRegionKind.Filter)
{
var v = new ILVariable(VariableKind.ExceptionStackSlot, compilation.FindType(KnownTypeCode.Object), eh.HandlerOffset) {
Name = "E_" + eh.HandlerOffset,
HasGeneratedName = true
};
variableByExceptionHandler.Add(eh, v);
ehStack = ImmutableStack.Create(v);
}
else
{
ehStack = ImmutableStack<ILVariable>.Empty;
}
if (eh.FilterOffset != -1)
{
isBranchTarget[eh.FilterOffset] = true;
StoreStackForOffset(eh.FilterOffset, ehStack);
}
if (eh.HandlerOffset != -1)
{
isBranchTarget[eh.HandlerOffset] = true;
StoreStackForOffset(eh.HandlerOffset, ehStack);
}
}
}
private void EnsureExceptionHandlersHaveBlocks()
{
// PrepareBranchTargetsAndStacksForExceptionHandlers enqueued filter/handler offsets
// so we have blocks for those; but it's possible that the TryOffset was never enqueued
// because it is unreachable.
// We need to ensure that we have blocks for all exception handler offsets,
// as otherwise the BlockBuilder will fail.
foreach (var eh in body.ExceptionRegions)
{
if (blocksByOffset.ContainsKey(eh.TryOffset))
continue;
// Create a dummy block for the try offset
var block = new ImportedBlock(eh.TryOffset, ImmutableStack<ILVariable>.Empty);
block.Block.Instructions.Add(new InvalidBranch("Unreachable try block"));
blocksByOffset.Add(eh.TryOffset, block);
}
// Note that after the BlockBuilder is done, it may delete the whole block containing
// the unreachable try-except construct, if it is completely unreachable.
}
private static bool IsSequencePointInstruction(ILInstruction instruction)
{
if (instruction.OpCode is OpCode.Nop
or OpCode.Call
or OpCode.CallIndirect
or OpCode.CallVirt)
{
return true;
}
else
{
return false;
}
}
/// <summary>
/// Debugging helper: writes the decoded instruction stream interleaved with the inferred evaluation stack layout.
/// </summary>
public void WriteTypedIL(MethodDefinitionHandle method, MethodBodyBlock body,
ITextOutput output, GenericContext genericContext = default, CancellationToken cancellationToken = default)
{
Init(method, body, genericContext);
ReadInstructions(cancellationToken);
foreach (var importBlock in blocksByOffset.Values.OrderBy(b => b.StartILOffset))
{
output.Write(" [");
bool isFirstElement = true;
foreach (var element in importBlock.InputStack)
{
if (isFirstElement)
isFirstElement = false;
else
output.Write(", ");
output.WriteLocalReference(element.Name, element);
output.Write(":");
output.Write(element.StackType);
}
output.Write(']');
output.WriteLine();
importBlock.Block.WriteTo(output, new ILAstWritingOptions());
output.WriteLine();
}
new Disassembler.MethodBodyDisassembler(output, cancellationToken) { DetectControlStructure = false }
.WriteExceptionHandlers(module.MetadataFile, method, body);
}
/// <summary>
/// Decodes the specified method body and returns an ILFunction.
/// </summary>
public ILFunction ReadIL(MethodDefinitionHandle method, MethodBodyBlock body, GenericContext genericContext = default, ILFunctionKind kind = ILFunctionKind.TopLevelFunction, CancellationToken cancellationToken = default)
{
cancellationToken.ThrowIfCancellationRequested();
Init(method, body, genericContext);
ReadInstructions(cancellationToken);
var blockBuilder = new BlockBuilder(body, variableByExceptionHandler, compilation);
blockBuilder.CreateBlocks(mainContainer, blocksByOffset.Values.Select(ib => ib.Block), cancellationToken);
var function = new ILFunction(this.method, body.GetCodeSize(), this.genericContext, mainContainer, kind);
function.Variables.AddRange(parameterVariables);
function.Variables.AddRange(localVariables);
function.LocalVariableSignatureLength = localVariables.Length;
Debug.Assert(stackVariables != null);
function.Variables.AddRange(stackVariables);
function.Variables.AddRange(variableByExceptionHandler.Values);
function.Variables.AddRange(blockBuilder.OnErrorDispatcherVariables);
function.AddRef(); // mark the root node
var removedBlocks = new List<Block>();
foreach (var c in function.Descendants.OfType<BlockContainer>())
{
var newOrder = c.TopologicalSort(deleteUnreachableBlocks: true);
if (newOrder.Count < c.Blocks.Count)
{
removedBlocks.AddRange(c.Blocks.Except(newOrder));
}
c.Blocks.ReplaceList(newOrder);
}
if (removedBlocks.Count > 0)
{
removedBlocks.SortBy(b => b.StartILOffset);
function.Warnings.Add("Discarded unreachable code: "
+ string.Join(", ", removedBlocks.Select(b => $"IL_{b.StartILOffset:x4}")));
}
this.SequencePointCandidates.Sort();
function.SequencePointCandidates = this.SequencePointCandidates;
function.Warnings.AddRange(Warnings);
return function;
}
DecodedInstruction Neg()
{
switch (PeekStackType())
{
case StackType.I4:
return Push(new BinaryNumericInstruction(BinaryNumericOperator.Sub, new LdcI4(0), Pop(), checkForOverflow: false, sign: Sign.None));
case StackType.I:
return Push(new BinaryNumericInstruction(BinaryNumericOperator.Sub, new Conv(new LdcI4(0), PrimitiveType.I, false, Sign.None), Pop(), checkForOverflow: false, sign: Sign.None));
case StackType.I8:
return Push(new BinaryNumericInstruction(BinaryNumericOperator.Sub, new LdcI8(0), Pop(), checkForOverflow: false, sign: Sign.None));
case StackType.F4:
return Push(new BinaryNumericInstruction(BinaryNumericOperator.Sub, new LdcF4(0), Pop(), checkForOverflow: false, sign: Sign.None));
case StackType.F8:
return Push(new BinaryNumericInstruction(BinaryNumericOperator.Sub, new LdcF8(0), Pop(), checkForOverflow: false, sign: Sign.None));
default:
Warn("Unsupported input type for neg.");
goto case StackType.I4;
}
}
struct DecodedInstruction
{
public ILInstruction Instruction;
public bool PushedOnExpressionStack;
public static implicit operator DecodedInstruction(ILInstruction instruction)
{
return new DecodedInstruction { Instruction = instruction };
}
}
DecodedInstruction DecodeInstruction()
{
if (reader.RemainingBytes == 0)
return new InvalidBranch("Unexpected end of body");
var opCode = ILParser.DecodeOpCode(ref reader);
switch (opCode)
{
case ILOpCode.Constrained:
return DecodeConstrainedCall();
case ILOpCode.Readonly:
return DecodeReadonly();
case ILOpCode.Tail:
return DecodeTailCall();
case ILOpCode.Unaligned:
return DecodeUnaligned();
case ILOpCode.Volatile:
return DecodeVolatile();
case ILOpCode.Add:
return BinaryNumeric(BinaryNumericOperator.Add);
case ILOpCode.Add_ovf:
return BinaryNumeric(BinaryNumericOperator.Add, true, Sign.Signed);
case ILOpCode.Add_ovf_un:
return BinaryNumeric(BinaryNumericOperator.Add, true, Sign.Unsigned);
case ILOpCode.And:
return BinaryNumeric(BinaryNumericOperator.BitAnd);
case ILOpCode.Arglist:
return Push(new Arglist());
case ILOpCode.Beq:
return DecodeComparisonBranch(opCode, ComparisonKind.Equality);
case ILOpCode.Beq_s:
return DecodeComparisonBranch(opCode, ComparisonKind.Equality);
case ILOpCode.Bge:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThanOrEqual);
case ILOpCode.Bge_s:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThanOrEqual);
case ILOpCode.Bge_un:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThanOrEqual, un: true);
case ILOpCode.Bge_un_s:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThanOrEqual, un: true);
case ILOpCode.Bgt:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThan);
case ILOpCode.Bgt_s:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThan);
case ILOpCode.Bgt_un:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThan, un: true);
case ILOpCode.Bgt_un_s:
return DecodeComparisonBranch(opCode, ComparisonKind.GreaterThan, un: true);
case ILOpCode.Ble:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThanOrEqual);
case ILOpCode.Ble_s:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThanOrEqual);
case ILOpCode.Ble_un:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThanOrEqual, un: true);
case ILOpCode.Ble_un_s:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThanOrEqual, un: true);
case ILOpCode.Blt:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThan);
case ILOpCode.Blt_s:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThan);
case ILOpCode.Blt_un:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThan, un: true);
case ILOpCode.Blt_un_s:
return DecodeComparisonBranch(opCode, ComparisonKind.LessThan, un: true);
case ILOpCode.Bne_un:
return DecodeComparisonBranch(opCode, ComparisonKind.Inequality, un: true);
case ILOpCode.Bne_un_s:
return DecodeComparisonBranch(opCode, ComparisonKind.Inequality, un: true);
case ILOpCode.Br:
return DecodeUnconditionalBranch(opCode);
case ILOpCode.Br_s:
return DecodeUnconditionalBranch(opCode);
case ILOpCode.Break:
return new DebugBreak();
case ILOpCode.Brfalse:
return DecodeConditionalBranch(opCode, true);
case ILOpCode.Brfalse_s:
return DecodeConditionalBranch(opCode, true);
case ILOpCode.Brtrue:
return DecodeConditionalBranch(opCode, false);
case ILOpCode.Brtrue_s:
return DecodeConditionalBranch(opCode, false);
case ILOpCode.Call:
return DecodeCall(OpCode.Call);
case ILOpCode.Callvirt:
return DecodeCall(OpCode.CallVirt);
case ILOpCode.Calli:
return DecodeCallIndirect();
case ILOpCode.Ceq:
return Push(Comparison(ComparisonKind.Equality));
case ILOpCode.Cgt:
return Push(Comparison(ComparisonKind.GreaterThan));
case ILOpCode.Cgt_un:
return Push(Comparison(ComparisonKind.GreaterThan, un: true));
case ILOpCode.Clt:
return Push(Comparison(ComparisonKind.LessThan));
case ILOpCode.Clt_un:
return Push(Comparison(ComparisonKind.LessThan, un: true));
case ILOpCode.Ckfinite:
return new Ckfinite(Peek());
case ILOpCode.Conv_i1:
return Push(new Conv(Pop(), PrimitiveType.I1, false, Sign.None));
case ILOpCode.Conv_i2:
return Push(new Conv(Pop(), PrimitiveType.I2, false, Sign.None));
case ILOpCode.Conv_i4:
return Push(new Conv(Pop(), PrimitiveType.I4, false, Sign.None));
case ILOpCode.Conv_i8:
return Push(new Conv(Pop(), PrimitiveType.I8, false, Sign.None));
case ILOpCode.Conv_r4:
return Push(new Conv(Pop(), PrimitiveType.R4, false, Sign.Signed));
case ILOpCode.Conv_r8:
return Push(new Conv(Pop(), PrimitiveType.R8, false, Sign.Signed));
case ILOpCode.Conv_u1:
return Push(new Conv(Pop(), PrimitiveType.U1, false, Sign.None));
case ILOpCode.Conv_u2:
return Push(new Conv(Pop(), PrimitiveType.U2, false, Sign.None));
case ILOpCode.Conv_u4:
return Push(new Conv(Pop(), PrimitiveType.U4, false, Sign.None));
case ILOpCode.Conv_u8:
return Push(new Conv(Pop(), PrimitiveType.U8, false, Sign.None));
case ILOpCode.Conv_i:
return Push(new Conv(Pop(), PrimitiveType.I, false, Sign.None));
case ILOpCode.Conv_u:
return Push(new Conv(Pop(), PrimitiveType.U, false, Sign.None));
case ILOpCode.Conv_r_un:
return Push(new Conv(Pop(), PrimitiveType.R, false, Sign.Unsigned));
case ILOpCode.Conv_ovf_i1:
return Push(new Conv(Pop(), PrimitiveType.I1, true, Sign.Signed));
case ILOpCode.Conv_ovf_i2:
return Push(new Conv(Pop(), PrimitiveType.I2, true, Sign.Signed));
case ILOpCode.Conv_ovf_i4:
return Push(new Conv(Pop(), PrimitiveType.I4, true, Sign.Signed));
case ILOpCode.Conv_ovf_i8:
return Push(new Conv(Pop(), PrimitiveType.I8, true, Sign.Signed));
case ILOpCode.Conv_ovf_u1:
return Push(new Conv(Pop(), PrimitiveType.U1, true, Sign.Signed));
case ILOpCode.Conv_ovf_u2:
return Push(new Conv(Pop(), PrimitiveType.U2, true, Sign.Signed));
case ILOpCode.Conv_ovf_u4:
return Push(new Conv(Pop(), PrimitiveType.U4, true, Sign.Signed));
case ILOpCode.Conv_ovf_u8:
return Push(new Conv(Pop(), PrimitiveType.U8, true, Sign.Signed));
case ILOpCode.Conv_ovf_i:
return Push(new Conv(Pop(), PrimitiveType.I, true, Sign.Signed));
case ILOpCode.Conv_ovf_u:
return Push(new Conv(Pop(), PrimitiveType.U, true, Sign.Signed));
case ILOpCode.Conv_ovf_i1_un:
return Push(new Conv(Pop(), PrimitiveType.I1, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_i2_un:
return Push(new Conv(Pop(), PrimitiveType.I2, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_i4_un:
return Push(new Conv(Pop(), PrimitiveType.I4, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_i8_un:
return Push(new Conv(Pop(), PrimitiveType.I8, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_u1_un:
return Push(new Conv(Pop(), PrimitiveType.U1, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_u2_un:
return Push(new Conv(Pop(), PrimitiveType.U2, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_u4_un:
return Push(new Conv(Pop(), PrimitiveType.U4, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_u8_un:
return Push(new Conv(Pop(), PrimitiveType.U8, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_i_un:
return Push(new Conv(Pop(), PrimitiveType.I, true, Sign.Unsigned));
case ILOpCode.Conv_ovf_u_un:
return Push(new Conv(Pop(), PrimitiveType.U, true, Sign.Unsigned));
case ILOpCode.Cpblk:
// This preserves the evaluation order because the ILAst will run
// destAddress; sourceAddress; size.
return new Cpblk(size: Pop(StackType.I4), sourceAddress: PopPointer(), destAddress: PopPointer());
case ILOpCode.Div:
return BinaryNumeric(BinaryNumericOperator.Div, false, Sign.Signed);
case ILOpCode.Div_un:
return BinaryNumeric(BinaryNumericOperator.Div, false, Sign.Unsigned);
case ILOpCode.Dup:
return Push(Peek());
case ILOpCode.Endfilter:
return new Leave(null, Pop());
case ILOpCode.Endfinally:
return new Leave(null);
case ILOpCode.Initblk:
// This preserves the evaluation order because the ILAst will run
// address; value; size.
return new Initblk(size: Pop(StackType.I4), value: Pop(StackType.I4), address: PopPointer());
case ILOpCode.Jmp:
return DecodeJmp();
case ILOpCode.Ldarg:
case ILOpCode.Ldarg_s:
return Push(Ldarg(ILParser.DecodeIndex(ref reader, opCode)));
case ILOpCode.Ldarg_0:
return Push(Ldarg(0));
case ILOpCode.Ldarg_1:
return Push(Ldarg(1));
case ILOpCode.Ldarg_2:
return Push(Ldarg(2));
case ILOpCode.Ldarg_3:
return Push(Ldarg(3));
case ILOpCode.Ldarga:
case ILOpCode.Ldarga_s:
return Push(Ldarga(ILParser.DecodeIndex(ref reader, opCode)));
case ILOpCode.Ldc_i4:
return Push(new LdcI4(reader.ReadInt32()));
case ILOpCode.Ldc_i8:
return Push(new LdcI8(reader.ReadInt64()));
case ILOpCode.Ldc_r4:
return Push(new LdcF4(reader.ReadSingle()));
case ILOpCode.Ldc_r8:
return Push(new LdcF8(reader.ReadDouble()));
case ILOpCode.Ldc_i4_m1:
return Push(new LdcI4(-1));
case ILOpCode.Ldc_i4_0:
return Push(new LdcI4(0));
case ILOpCode.Ldc_i4_1:
return Push(new LdcI4(1));
case ILOpCode.Ldc_i4_2:
return Push(new LdcI4(2));
case ILOpCode.Ldc_i4_3:
return Push(new LdcI4(3));
case ILOpCode.Ldc_i4_4:
return Push(new LdcI4(4));
case ILOpCode.Ldc_i4_5:
return Push(new LdcI4(5));
case ILOpCode.Ldc_i4_6:
return Push(new LdcI4(6));
case ILOpCode.Ldc_i4_7:
return Push(new LdcI4(7));
case ILOpCode.Ldc_i4_8:
return Push(new LdcI4(8));
case ILOpCode.Ldc_i4_s:
return Push(new LdcI4(reader.ReadSByte()));
case ILOpCode.Ldnull:
return Push(new LdNull());
case ILOpCode.Ldstr:
return Push(DecodeLdstr());
case ILOpCode.Ldftn:
return Push(new LdFtn(ReadAndDecodeMethodReference()));
case ILOpCode.Ldind_i1:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.SByte)));
case ILOpCode.Ldind_i2:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Int16)));
case ILOpCode.Ldind_i4:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Int32)));
case ILOpCode.Ldind_i8:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Int64)));
case ILOpCode.Ldind_u1:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Byte)));
case ILOpCode.Ldind_u2:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.UInt16)));
case ILOpCode.Ldind_u4:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.UInt32)));
case ILOpCode.Ldind_r4:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Single)));
case ILOpCode.Ldind_r8:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Double)));
case ILOpCode.Ldind_i:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.IntPtr)));
case ILOpCode.Ldind_ref:
return Push(new LdObj(PopPointer(), compilation.FindType(KnownTypeCode.Object)));
case ILOpCode.Ldloc:
case ILOpCode.Ldloc_s:
return Push(Ldloc(ILParser.DecodeIndex(ref reader, opCode)));
case ILOpCode.Ldloc_0:
return Push(Ldloc(0));
case ILOpCode.Ldloc_1:
return Push(Ldloc(1));
case ILOpCode.Ldloc_2:
return Push(Ldloc(2));
case ILOpCode.Ldloc_3:
return Push(Ldloc(3));
case ILOpCode.Ldloca:
case ILOpCode.Ldloca_s:
return Push(Ldloca(ILParser.DecodeIndex(ref reader, opCode)));
case ILOpCode.Leave:
return DecodeUnconditionalBranch(opCode, isLeave: true);
case ILOpCode.Leave_s:
return DecodeUnconditionalBranch(opCode, isLeave: true);
case ILOpCode.Localloc:
return Push(new LocAlloc(Pop()));
case ILOpCode.Mul:
return BinaryNumeric(BinaryNumericOperator.Mul, false, Sign.None);
case ILOpCode.Mul_ovf:
return BinaryNumeric(BinaryNumericOperator.Mul, true, Sign.Signed);
case ILOpCode.Mul_ovf_un:
return BinaryNumeric(BinaryNumericOperator.Mul, true, Sign.Unsigned);
case ILOpCode.Neg:
return Neg();
case ILOpCode.Newobj:
return DecodeCall(OpCode.NewObj);
case ILOpCode.Nop:
return new Nop();
case ILOpCode.Not:
return Push(new BitNot(Pop()));
case ILOpCode.Or:
return BinaryNumeric(BinaryNumericOperator.BitOr);
case ILOpCode.Pop:
FlushExpressionStack(); // discard only the value, not the side-effects
Pop();
return new Nop() { Kind = NopKind.Pop };
case ILOpCode.Rem:
return BinaryNumeric(BinaryNumericOperator.Rem, false, Sign.Signed);
case ILOpCode.Rem_un:
return BinaryNumeric(BinaryNumericOperator.Rem, false, Sign.Unsigned);
case ILOpCode.Ret:
return Return();
case ILOpCode.Shl:
return BinaryNumeric(BinaryNumericOperator.ShiftLeft, false, Sign.None);
case ILOpCode.Shr:
return BinaryNumeric(BinaryNumericOperator.ShiftRight, false, Sign.Signed);
case ILOpCode.Shr_un:
return BinaryNumeric(BinaryNumericOperator.ShiftRight, false, Sign.Unsigned);
case ILOpCode.Starg:
case ILOpCode.Starg_s:
return Starg(ILParser.DecodeIndex(ref reader, opCode));
case ILOpCode.Stind_i1:
// target will run before value, thus preserving the evaluation order
return new StObj(value: Pop(StackType.I4), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.SByte));
case ILOpCode.Stind_i2:
return new StObj(value: Pop(StackType.I4), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.Int16));
case ILOpCode.Stind_i4:
return new StObj(value: Pop(StackType.I4), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.Int32));
case ILOpCode.Stind_i8:
return new StObj(value: Pop(StackType.I8), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.Int64));
case ILOpCode.Stind_r4:
return new StObj(value: Pop(StackType.F4), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.Single));
case ILOpCode.Stind_r8:
return new StObj(value: Pop(StackType.F8), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.Double));
case ILOpCode.Stind_i:
return new StObj(value: Pop(StackType.I), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.IntPtr));
case ILOpCode.Stind_ref:
return new StObj(value: Pop(StackType.O), target: PopStObjTarget(), type: compilation.FindType(KnownTypeCode.Object));
case ILOpCode.Stloc:
case ILOpCode.Stloc_s:
return Stloc(ILParser.DecodeIndex(ref reader, opCode));
case ILOpCode.Stloc_0:
return Stloc(0);
case ILOpCode.Stloc_1:
return Stloc(1);
case ILOpCode.Stloc_2:
return Stloc(2);
case ILOpCode.Stloc_3:
return Stloc(3);
case ILOpCode.Sub:
return BinaryNumeric(BinaryNumericOperator.Sub, false, Sign.None);
case ILOpCode.Sub_ovf:
return BinaryNumeric(BinaryNumericOperator.Sub, true, Sign.Signed);
case ILOpCode.Sub_ovf_un:
return BinaryNumeric(BinaryNumericOperator.Sub, true, Sign.Unsigned);
case ILOpCode.Switch:
return DecodeSwitch();
case ILOpCode.Xor:
return BinaryNumeric(BinaryNumericOperator.BitXor);
case ILOpCode.Box:
{
var type = ReadAndDecodeTypeReference();
return Push(new Box(Pop(type.GetStackType()), type));
}
case ILOpCode.Castclass:
return Push(new CastClass(Pop(StackType.O), ReadAndDecodeTypeReference()));
case ILOpCode.Cpobj:
{
var type = ReadAndDecodeTypeReference();
// OK, 'target' runs before 'value: ld'
var ld = new LdObj(PopPointer(), type);
return new StObj(PopStObjTarget(), ld, type);
}
case ILOpCode.Initobj:
return InitObj(PopStObjTarget(), ReadAndDecodeTypeReference());
case ILOpCode.Isinst:
return Push(new IsInst(Pop(StackType.O), ReadAndDecodeTypeReference()));
case ILOpCode.Ldelem:
return LdElem(ReadAndDecodeTypeReference());
case ILOpCode.Ldelem_i1:
return LdElem(compilation.FindType(KnownTypeCode.SByte));
case ILOpCode.Ldelem_i2:
return LdElem(compilation.FindType(KnownTypeCode.Int16));
case ILOpCode.Ldelem_i4:
return LdElem(compilation.FindType(KnownTypeCode.Int32));
case ILOpCode.Ldelem_i8:
return LdElem(compilation.FindType(KnownTypeCode.Int64));
case ILOpCode.Ldelem_u1:
return LdElem(compilation.FindType(KnownTypeCode.Byte));
case ILOpCode.Ldelem_u2:
return LdElem(compilation.FindType(KnownTypeCode.UInt16));
case ILOpCode.Ldelem_u4:
return LdElem(compilation.FindType(KnownTypeCode.UInt32));
case ILOpCode.Ldelem_r4:
return LdElem(compilation.FindType(KnownTypeCode.Single));
case ILOpCode.Ldelem_r8:
return LdElem(compilation.FindType(KnownTypeCode.Double));
case ILOpCode.Ldelem_i:
return LdElem(compilation.FindType(KnownTypeCode.IntPtr));
case ILOpCode.Ldelem_ref:
return LdElem(compilation.FindType(KnownTypeCode.Object));
case ILOpCode.Ldelema:
// LdElema will evalute the array before the indices, so we're preserving the evaluation order
return Push(new LdElema(indices: Pop(), array: Pop(), type: ReadAndDecodeTypeReference()));
case ILOpCode.Ldfld:
{
var field = ReadAndDecodeFieldReference();
return Push(new LdObj(new LdFlda(PopLdFldTarget(field), field) { DelayExceptions = true }, field.Type));
}
case ILOpCode.Ldflda:
{
var field = ReadAndDecodeFieldReference();
return Push(new LdFlda(PopFieldTarget(field), field));
}
case ILOpCode.Stfld:
{
var field = ReadAndDecodeFieldReference();
return new StObj(value: Pop(field.Type.GetStackType()), target: new LdFlda(PopFieldTarget(field), field) { DelayExceptions = true }, type: field.Type);
}
case ILOpCode.Ldlen:
return Push(new LdLen(StackType.I, Pop(StackType.O)));
case ILOpCode.Ldobj:
return Push(new LdObj(PopPointer(), ReadAndDecodeTypeReference()));
case ILOpCode.Ldsfld:
{
var field = ReadAndDecodeFieldReference();
return Push(new LdObj(new LdsFlda(field), field.Type));
}
case ILOpCode.Ldsflda:
return Push(new LdsFlda(ReadAndDecodeFieldReference()));
case ILOpCode.Stsfld:
{
var field = ReadAndDecodeFieldReference();
return new StObj(value: Pop(field.Type.GetStackType()), target: new LdsFlda(field), type: field.Type);
}
case ILOpCode.Ldtoken:
return Push(LdToken(ReadAndDecodeMetadataToken()));
case ILOpCode.Ldvirtftn:
return Push(new LdVirtFtn(Pop(), ReadAndDecodeMethodReference()));
case ILOpCode.Mkrefany:
return Push(new MakeRefAny(PopPointer(), ReadAndDecodeTypeReference()));
case ILOpCode.Newarr:
return Push(new NewArr(ReadAndDecodeTypeReference(), Pop()));
case ILOpCode.Refanytype:
return Push(new RefAnyType(Pop()));
case ILOpCode.Refanyval:
return Push(new RefAnyValue(Pop(), ReadAndDecodeTypeReference()));
case ILOpCode.Rethrow:
return new Rethrow();
case ILOpCode.Sizeof:
return Push(new SizeOf(ReadAndDecodeTypeReference()));
case ILOpCode.Stelem:
return StElem(ReadAndDecodeTypeReference());
case ILOpCode.Stelem_i1:
return StElem(compilation.FindType(KnownTypeCode.SByte));
case ILOpCode.Stelem_i2:
return StElem(compilation.FindType(KnownTypeCode.Int16));
case ILOpCode.Stelem_i4:
return StElem(compilation.FindType(KnownTypeCode.Int32));
case ILOpCode.Stelem_i8:
return StElem(compilation.FindType(KnownTypeCode.Int64));
case ILOpCode.Stelem_r4:
return StElem(compilation.FindType(KnownTypeCode.Single));
case ILOpCode.Stelem_r8:
return StElem(compilation.FindType(KnownTypeCode.Double));
case ILOpCode.Stelem_i:
return StElem(compilation.FindType(KnownTypeCode.IntPtr));
case ILOpCode.Stelem_ref:
return StElem(compilation.FindType(KnownTypeCode.Object));
case ILOpCode.Stobj:
{
var type = ReadAndDecodeTypeReference();
// OK, target runs before value
return new StObj(value: Pop(type.GetStackType()), target: PopStObjTarget(), type: type);
}
case ILOpCode.Throw:
return new Throw(Pop());
case ILOpCode.Unbox:
return Push(new Unbox(Pop(), ReadAndDecodeTypeReference()));
case ILOpCode.Unbox_any:
return Push(new UnboxAny(Pop(), ReadAndDecodeTypeReference()));
default:
return new InvalidBranch($"Unknown opcode: 0x{(int)opCode:X2}");
}
}
StackType PeekStackType()
{
if (expressionStack.Count > 0)
return expressionStack.Last().ResultType;
if (currentStack.IsEmpty)
return StackType.Unknown;
else
return currentStack.Peek().StackType;
}
sealed class CollectStackVariablesVisitor : ILVisitor<ILInstruction>
{
readonly UnionFind<ILVariable> unionFind;
internal readonly HashSet<ILVariable> variables = new HashSet<ILVariable>();
public CollectStackVariablesVisitor(UnionFind<ILVariable> unionFind)
{
Debug.Assert(unionFind != null);
this.unionFind = unionFind;
}
protected override ILInstruction Default(ILInstruction inst)
{
foreach (var child in inst.Children)
{
var newChild = child.AcceptVisitor(this);
if (newChild != child)
child.ReplaceWith(newChild);
}
return inst;
}
protected internal override ILInstruction VisitLdLoc(LdLoc inst)
{
base.VisitLdLoc(inst);
if (inst.Variable.Kind == VariableKind.StackSlot)
{
var variable = unionFind.Find(inst.Variable);
if (variables.Add(variable))
variable.Name = $"S_{variables.Count - 1}";
return new LdLoc(variable).WithILRange(inst);
}
return inst;
}
protected internal override ILInstruction VisitStLoc(StLoc inst)
{
base.VisitStLoc(inst);
if (inst.Variable.Kind == VariableKind.StackSlot)
{
var variable = unionFind.Find(inst.Variable);
if (variables.Add(variable))
variable.Name = $"S_{variables.Count - 1}";
return new StLoc(variable, inst.Value).WithILRange(inst);
}
return inst;
}
}
DecodedInstruction Push(ILInstruction inst)
{
expressionStack.Add(inst);
return new DecodedInstruction {
Instruction = inst,
PushedOnExpressionStack = true
};
}
ILInstruction Peek()
{
FlushExpressionStack();
if (currentStack.IsEmpty)
{
return new InvalidExpression("Stack underflow").WithILRange(new Interval(reader.Offset, reader.Offset));
}
return new LdLoc(currentStack.Peek());
}
/// <summary>
/// Pops a value/instruction from the evaluation stack.
/// Note that instructions popped from the stack must be evaluated in the order they
/// were pushed (so in reverse order of the pop calls!).
///
/// For instructions like 'conv' that pop a single element and then push their result,
/// it's fine to pop just one element as the instruction itself will end up on the stack,
/// thus maintaining the evaluation order.
/// For instructions like 'call' that pop multiple arguments, it's critical that
/// the evaluation order of the resulting ILAst will be reverse from the order of the push
/// calls.
/// For instructions like 'brtrue', it's fine to pop only a part of the stack because
/// ReadInstructions() will flush the evaluation stack before outputting the brtrue instruction.
///
/// Use FlushExpressionStack() to ensure that following Pop() calls do not return
/// instructions that involve side-effects. This way evaluation order is preserved
/// no matter which order the ILAst will execute the popped instructions in.
/// </summary>
ILInstruction Pop()
{
if (expressionStack.Count > 0)
{
var inst = expressionStack.Last();
expressionStack.RemoveAt(expressionStack.Count - 1);
return inst;
}
if (currentStack.IsEmpty)
{
return new InvalidExpression("Stack underflow").WithILRange(new Interval(reader.Offset, reader.Offset));
}
ILVariable v;
currentStack = currentStack.Pop(out v);
return new LdLoc(v);
}
ILInstruction Pop(StackType expectedType)
{
ILInstruction inst = Pop();
return Cast(inst, expectedType, Warnings, reader.Offset);
}
internal static ILInstruction Cast(ILInstruction inst, StackType expectedType, List<string>? warnings, int ilOffset)
{
if (expectedType != inst.ResultType)
{
if (inst is InvalidExpression)
{
((InvalidExpression)inst).ExpectedResultType = expectedType;
}
else if (expectedType == StackType.I && inst.ResultType == StackType.I4)
{
// IL allows implicit I4->I conversions
inst = new Conv(inst, PrimitiveType.I, false, Sign.None);
}
else if (expectedType == StackType.I4 && inst.ResultType == StackType.I)
{
// C++/CLI also sometimes implicitly converts in the other direction:
inst = new Conv(inst, PrimitiveType.I4, false, Sign.None);
}
else if (expectedType == StackType.Unknown)
{
inst = new Conv(inst, PrimitiveType.Unknown, false, Sign.None);
}
else if (inst.ResultType == StackType.Ref)
{
// Implicitly stop GC tracking; this occurs when passing the result of 'ldloca' or 'ldsflda'
// to a method expecting a native pointer.
inst = new Conv(inst, PrimitiveType.I, false, Sign.None);
switch (expectedType)
{
case StackType.I4:
inst = new Conv(inst, PrimitiveType.I4, false, Sign.None);
break;
case StackType.I:
break;
case StackType.I8:
inst = new Conv(inst, PrimitiveType.I8, false, Sign.None);
break;
default:
Warn($"Expected {expectedType}, but got {StackType.Ref}");
inst = new Conv(inst, expectedType.ToPrimitiveType(), false, Sign.None);
break;
}
}
else if (expectedType == StackType.Ref)
{
// implicitly start GC tracking / object to interior
if (!inst.ResultType.IsIntegerType() && inst.ResultType != StackType.O)
{
// We also handle the invalid to-ref cases here because the else case
// below uses expectedType.ToKnownTypeCode(), which doesn't work for Ref.
Warn($"Expected {expectedType}, but got {inst.ResultType}");
}
inst = new Conv(inst, PrimitiveType.Ref, false, Sign.None);
}
else if (expectedType == StackType.F8 && inst.ResultType == StackType.F4)
{
// IL allows implicit F4->F8 conversions, because in IL F4 and F8 are the same.
inst = new Conv(inst, PrimitiveType.R8, false, Sign.Signed);
}
else if (expectedType == StackType.F4 && inst.ResultType == StackType.F8)
{
// IL allows implicit F8->F4 conversions, because in IL F4 and F8 are the same.
inst = new Conv(inst, PrimitiveType.R4, false, Sign.Signed);
}
else
{
Warn($"Expected {expectedType}, but got {inst.ResultType}");
inst = new Conv(inst, expectedType.ToPrimitiveType(), false, Sign.Signed);
}
}
return inst;
void Warn(string message)
{
if (warnings != null)
{
warnings.Add(string.Format("IL_{0:x4}: {1}", ilOffset, message));
}
}
}
ILInstruction PopPointer()
{
ILInstruction inst = Pop();
switch (inst.ResultType)
{
case StackType.I4:
case StackType.I8:
case StackType.Unknown:
return new Conv(inst, PrimitiveType.I, false, Sign.None);
case StackType.I:
case StackType.Ref:
return inst;
default:
Warn("Expected native int or pointer, but got " + inst.ResultType);
return new Conv(inst, PrimitiveType.I, false, Sign.None);
}
}
ILInstruction PopStObjTarget()
{
// stobj has a special invariant (StObj.CheckTargetSlot)
// that prohibits inlining LdElema/LdFlda.
if (expressionStack.LastOrDefault() is LdElema or LdFlda)
{
FlushExpressionStack();
}
return PopPointer();
}
ILInstruction PopFieldTarget(IField field)
{
switch (field.DeclaringType.IsReferenceType)
{
case true:
return Pop(StackType.O);
case false:
return PopPointer();
default:
// field in unresolved type
var stackType = PeekStackType();
if (stackType == StackType.O || stackType == StackType.Unknown)
return Pop();
else
return PopPointer();
}
}
/// <summary>
/// Like PopFieldTarget, but supports ldfld's special behavior for fields of temporary value types.
/// </summary>
ILInstruction PopLdFldTarget(IField field)
{
switch (field.DeclaringType.IsReferenceType)
{
case true:
return Pop(StackType.O);
case false:
// field of value type: ldfld can handle temporaries
if (PeekStackType() == StackType.O || PeekStackType() == StackType.Unknown)
return new AddressOf(Pop(), field.DeclaringType);
else
return PopPointer();
default:
// field in unresolved type
if (PeekStackType() == StackType.O || PeekStackType() == StackType.Unknown)
return Pop();
else
return PopPointer();
}
}
private ILInstruction Return()
{
if (methodReturnStackType == StackType.Void)
{
return new IL.Leave(mainContainer);
}
else if (currentInstructionStart == 0)
{
Debug.Assert(expressionStack.Count == 0 && currentStack.IsEmpty);
return new InvalidBranch("Method body consists only of 'ret', but nothing is being returned. Decompiled assembly might be a reference assembly.");
}
else
{
return new IL.Leave(mainContainer, Pop(methodReturnStackType));
}
}
private ILInstruction DecodeLdstr()
{
return new LdStr(ILParser.DecodeUserString(ref reader, metadata));
}
private ILInstruction Ldarg(int v)
{
if (v >= 0 && v < parameterVariables.Length)
{
return new LdLoc(parameterVariables[v]);
}
else
{
return new InvalidExpression($"ldarg {v} (out-of-bounds)");
}
}
private ILInstruction Ldarga(int v)
{
if (v >= 0 && v < parameterVariables.Length)
{
return new LdLoca(parameterVariables[v]);
}
else
{
return new InvalidExpression($"ldarga {v} (out-of-bounds)");
}
}
private ILInstruction Starg(int v)
{
if (v >= 0 && v < parameterVariables.Length)
{
return new StLoc(parameterVariables[v], Pop(parameterVariables[v].StackType));
}
else
{
FlushExpressionStack();
Pop();
return new InvalidExpression($"starg {v} (out-of-bounds)");
}
}
private ILInstruction Ldloc(int v)
{
if (v >= 0 && v < localVariables.Length)
{
return new LdLoc(localVariables[v]);
}
else
{
return new InvalidExpression($"ldloc {v} (out-of-bounds)");
}
}
private ILInstruction Ldloca(int v)
{
if (v >= 0 && v < localVariables.Length)
{
return new LdLoca(localVariables[v]);
}
else
{
return new InvalidExpression($"ldloca {v} (out-of-bounds)");
}
}
private ILInstruction Stloc(int v)
{
if (v >= 0 && v < localVariables.Length)
{
return new StLoc(localVariables[v], Pop(localVariables[v].StackType)) {
ILStackWasEmpty = CurrentStackIsEmpty()
};
}
else
{
FlushExpressionStack();
Pop();
return new InvalidExpression($"stloc {v} (out-of-bounds)");
}
}
private DecodedInstruction LdElem(IType type)
{
return Push(new LdObj(new LdElema(indices: Pop(), array: Pop(), type: type) { DelayExceptions = true }, type));
}
private ILInstruction StElem(IType type)
{
var value = Pop(type.GetStackType());
var index = Pop();
var array = Pop();
// OK, evaluation order is array, index, value
return new StObj(new LdElema(type, array, index) { DelayExceptions = true }, value, type);
}
ILInstruction InitObj(ILInstruction target, IType type)
{
var value = new DefaultValue(type);
value.ILStackWasEmpty = CurrentStackIsEmpty();
return new StObj(target, value, type);
}
IType? constrainedPrefix;
private DecodedInstruction DecodeConstrainedCall()
{
constrainedPrefix = ReadAndDecodeTypeReference();
var inst = DecodeInstruction();
var call = inst.Instruction as CallInstruction;
if (call != null)
Debug.Assert(call.ConstrainedTo == constrainedPrefix);
else
Warn("Ignored invalid 'constrained' prefix");
constrainedPrefix = null;
return inst;
}
private DecodedInstruction DecodeTailCall()
{
var inst = DecodeInstruction();
var call = inst.Instruction as CallInstruction;
if (call != null)
call.IsTail = true;
else
Warn("Ignored invalid 'tail' prefix");
return inst;
}
private DecodedInstruction DecodeUnaligned()
{
byte alignment = reader.ReadByte();
var inst = DecodeInstruction();
var sup = inst.Instruction as ISupportsUnalignedPrefix;
if (sup != null)
sup.UnalignedPrefix = alignment;
else
Warn("Ignored invalid 'unaligned' prefix");
return inst;
}
private DecodedInstruction DecodeVolatile()
{
var inst = DecodeInstruction();
var svp = inst.Instruction as ISupportsVolatilePrefix;
if (svp != null)
svp.IsVolatile = true;
else
Warn("Ignored invalid 'volatile' prefix");
return inst;
}
private DecodedInstruction DecodeReadonly()
{
var inst = DecodeInstruction();
var ldelema = inst.Instruction as LdElema;
if (ldelema != null)
ldelema.IsReadOnly = true;
else
Warn("Ignored invalid 'readonly' prefix");
return inst;
}
DecodedInstruction DecodeCall(OpCode opCode)
{
var method = ReadAndDecodeMethodReference();
ILInstruction[] arguments;
switch (method.DeclaringType.Kind)
{
case TypeKind.Array:
{
arguments = PrepareArguments(firstArgumentIsStObjTarget: false);
var elementType = ((ArrayType)method.DeclaringType).ElementType;
if (opCode == OpCode.NewObj)
return Push(new NewArr(elementType, arguments));
if (method.Name == "Set")
{
var target = arguments[0];
var indices = arguments.Skip(1).Take(arguments.Length - 2).ToArray();
var value = arguments.Last();
// preserves evaluation order target,indices,value
return new StObj(new LdElema(elementType, target, indices) { DelayExceptions = true }, value, elementType);
}
if (method.Name == "Get")
{
var target = arguments[0];
var indices = arguments.Skip(1).ToArray();
// preserves evaluation order target,indices
return Push(new LdObj(new LdElema(elementType, target, indices) { DelayExceptions = true }, elementType));
}
if (method.Name == "Address")
{
var target = arguments[0];
var indices = arguments.Skip(1).ToArray();
// preserves evaluation order target,indices
return Push(new LdElema(elementType, target, indices));
}
Warn("Unknown method called on array type: " + method.Name);
goto default;
}
case TypeKind.Struct when method.IsConstructor && !method.IsStatic && opCode == OpCode.Call
&& method.ReturnType.Kind == TypeKind.Void:
{
// "call Struct.ctor(target, ...)" doesn't exist in C#,
// the next best equivalent is an assignment `*target = new Struct(...);`.
// So we represent this call as "stobj Struct(target, newobj Struct.ctor(...))".
// This needs to happen early (not as a transform) because the StObj.TargetSlot has
// restricted inlining (doesn't accept ldflda when exceptions aren't delayed).
arguments = PrepareArguments(firstArgumentIsStObjTarget: true);
var newobj = new NewObj(method);
newobj.ILStackWasEmpty = CurrentStackIsEmpty();
newobj.ConstrainedTo = constrainedPrefix;
newobj.Arguments.AddRange(arguments.Skip(1));
return new StObj(arguments[0], newobj, method.DeclaringType);
}
default:
arguments = PrepareArguments(firstArgumentIsStObjTarget: false);
var call = CallInstruction.Create(opCode, method);
call.ILStackWasEmpty = CurrentStackIsEmpty();
call.ConstrainedTo = constrainedPrefix;
call.Arguments.AddRange(arguments);
if (call.ResultType != StackType.Void)
return Push(call);
return call;
}
ILInstruction[] PrepareArguments(bool firstArgumentIsStObjTarget)
{
int firstArgument = (opCode != OpCode.NewObj && !method.IsStatic) ? 1 : 0;
var arguments = new ILInstruction[firstArgument + method.Parameters.Count];
IType typeOfThis = constrainedPrefix ?? method.DeclaringType;
StackType expectedStackType = CallInstruction.ExpectedTypeForThisPointer(method.DeclaringType, constrainedPrefix);
bool requiresLdObjIfRef = firstArgument == 1
&& !firstArgumentIsStObjTarget
&& UseRefLocalsForAccurateOrderOfEvaluation
&& expectedStackType == StackType.Ref && typeOfThis.IsReferenceType != false;
for (int i = method.Parameters.Count - 1; i >= 0; i--)
{
if (requiresLdObjIfRef)
{
FlushExpressionStack();
}
arguments[firstArgument + i] = Pop(method.Parameters[i].Type.GetStackType());
}
if (firstArgument == 1)
{
ILInstruction firstArgumentInstruction;
if (firstArgumentIsStObjTarget)
{
firstArgumentInstruction = PopStObjTarget();
}
else
{
firstArgumentInstruction = Pop(expectedStackType);
if (requiresLdObjIfRef)
{
firstArgumentInstruction = new LdObjIfRef(firstArgumentInstruction, typeOfThis);
}
}
arguments[0] = firstArgumentInstruction;
}
// arguments is in reverse order of the Pop calls, thus
// arguments is now in the correct evaluation order.
return arguments;
}
}
DecodedInstruction DecodeCallIndirect()
{
StandaloneSignatureHandle signatureHandle;
try
{
signatureHandle = (StandaloneSignatureHandle)ReadAndDecodeMetadataToken();
}
catch (InvalidCastException ex)
{
throw new BadImageFormatException("Invalid calli metadata token", ex);
}
var (header, fpt) = module.DecodeMethodSignature(signatureHandle, genericContext);
var functionPointer = Pop(StackType.I);
int firstArgument = header.IsInstance ? 1 : 0;
var arguments = new ILInstruction[firstArgument + fpt.ParameterTypes.Length];
for (int i = fpt.ParameterTypes.Length - 1; i >= 0; i--)
{
arguments[firstArgument + i] = Pop(fpt.ParameterTypes[i].GetStackType());
}
if (firstArgument == 1)
{
arguments[0] = Pop();
}
// arguments is in reverse order of the Pop calls, thus
// arguments is now in the correct evaluation order.
var call = new CallIndirect(
header.IsInstance,
header.HasExplicitThis,
fpt,
functionPointer,
arguments
);
if (call.ResultType != StackType.Void)
return Push(call);
else
return call;
}
ILInstruction Comparison(ComparisonKind kind, bool un = false)
{
var right = Pop();
var left = Pop();
// left will run before right, thus preserving the evaluation order
if ((left.ResultType == StackType.O || left.ResultType == StackType.Ref) && right.ResultType.IsIntegerType())
{
// C++/CLI sometimes compares object references with integers.
// Also happens with Ref==I in Unsafe.IsNullRef().
if (right.ResultType == StackType.I4)
{
// ensure we compare at least native integer size
right = new Conv(right, PrimitiveType.I, false, Sign.None);
}
left = new Conv(left, right.ResultType.ToPrimitiveType(), false, Sign.None);
}
else if ((right.ResultType == StackType.O || right.ResultType == StackType.Ref) && left.ResultType.IsIntegerType())
{
if (left.ResultType == StackType.I4)
{
left = new Conv(left, PrimitiveType.I, false, Sign.None);
}
right = new Conv(right, left.ResultType.ToPrimitiveType(), false, Sign.None);
}
// make implicit integer conversions explicit:
MakeExplicitConversion(sourceType: StackType.I4, targetType: StackType.I, conversionType: PrimitiveType.I);
MakeExplicitConversion(sourceType: StackType.I4, targetType: StackType.I8, conversionType: PrimitiveType.I8);
MakeExplicitConversion(sourceType: StackType.I, targetType: StackType.I8, conversionType: PrimitiveType.I8);
// Based on Table 4: Binary Comparison or Branch Operation
if (left.ResultType.IsFloatType() && right.ResultType.IsFloatType())
{
if (left.ResultType != right.ResultType)
{
// make the implicit F4->F8 conversion explicit:
MakeExplicitConversion(StackType.F4, StackType.F8, PrimitiveType.R8);
}
if (un)
{
// for floats, 'un' means 'unordered'
return Comp.LogicNot(new Comp(kind.Negate(), Sign.None, left, right));
}
else
{
return new Comp(kind, Sign.None, left, right);
}
}
else if (left.ResultType.IsIntegerType() && right.ResultType.IsIntegerType() && !kind.IsEqualityOrInequality())
{
// integer comparison where the sign matters
Debug.Assert(right.ResultType.IsIntegerType());
return new Comp(kind, un ? Sign.Unsigned : Sign.Signed, left, right);
}
else if (left.ResultType == right.ResultType)
{
// integer equality, object reference or managed reference comparison
return new Comp(kind, Sign.None, left, right);
}
else
{
Warn($"Invalid comparison between {left.ResultType} and {right.ResultType}");
if (left.ResultType < right.ResultType)
{
left = new Conv(left, right.ResultType.ToPrimitiveType(), false, Sign.Signed);
}
else
{
right = new Conv(right, left.ResultType.ToPrimitiveType(), false, Sign.Signed);
}
return new Comp(kind, Sign.None, left, right);
}
void MakeExplicitConversion(StackType sourceType, StackType targetType, PrimitiveType conversionType)
{
if (left.ResultType == sourceType && right.ResultType == targetType)
{
left = new Conv(left, conversionType, false, Sign.None);
}
else if (left.ResultType == targetType && right.ResultType == sourceType)
{
right = new Conv(right, conversionType, false, Sign.None);
}
}
}
bool IsInvalidBranch(int target) => target < 0 || target >= reader.Length;
ILInstruction DecodeComparisonBranch(ILOpCode opCode, ComparisonKind kind, bool un = false)
{
int start = reader.Offset - 1; // opCode is always one byte in this case
int target = ILParser.DecodeBranchTarget(ref reader, opCode);
var condition = Comparison(kind, un);
condition.AddILRange(new Interval(start, reader.Offset));
if (!IsInvalidBranch(target))
{
MarkBranchTarget(target);
return new IfInstruction(condition, new Branch(target));
}
else
{
return new IfInstruction(condition, new InvalidBranch("Invalid branch target"));
}
}
ILInstruction DecodeConditionalBranch(ILOpCode opCode, bool negate)
{
int target = ILParser.DecodeBranchTarget(ref reader, opCode);
ILInstruction condition = Pop();
switch (condition.ResultType)
{
case StackType.O:
// introduce explicit comparison with null
condition = new Comp(
negate ? ComparisonKind.Equality : ComparisonKind.Inequality,
Sign.None, condition, new LdNull());
break;
case StackType.I:
// introduce explicit comparison with 0
condition = new Comp(
negate ? ComparisonKind.Equality : ComparisonKind.Inequality,
Sign.None, condition, new Conv(new LdcI4(0), PrimitiveType.I, false, Sign.None));
break;
case StackType.I8:
// introduce explicit comparison with 0
condition = new Comp(
negate ? ComparisonKind.Equality : ComparisonKind.Inequality,
Sign.None, condition, new LdcI8(0));
break;
case StackType.Ref:
// introduce explicit comparison with null ref
condition = new Comp(
negate ? ComparisonKind.Equality : ComparisonKind.Inequality,
Sign.None, new Conv(condition, PrimitiveType.I, false, Sign.None), new Conv(new LdcI4(0), PrimitiveType.I, false, Sign.None));
break;
case StackType.I4:
if (negate)
{
condition = Comp.LogicNot(condition);
}
break;
default:
condition = new Conv(condition, PrimitiveType.I4, false, Sign.None);
if (negate)
{
condition = Comp.LogicNot(condition);
}
break;
}
if (!IsInvalidBranch(target))
{
MarkBranchTarget(target);
return new IfInstruction(condition, new Branch(target));
}
else
{
return new IfInstruction(condition, new InvalidBranch("Invalid branch target"));
}
}
ILInstruction DecodeUnconditionalBranch(ILOpCode opCode, bool isLeave = false)
{
int target = ILParser.DecodeBranchTarget(ref reader, opCode);
if (isLeave)
{
FlushExpressionStack();
currentStack = currentStack.Clear();
}
if (!IsInvalidBranch(target))
{
MarkBranchTarget(target);
return new Branch(target);
}
else
{
return new InvalidBranch("Invalid branch target");
}
}
void MarkBranchTarget(int targetILOffset, bool isFallThrough = false)
{
FlushExpressionStack();
Debug.Assert(isFallThrough || isBranchTarget[targetILOffset]);
var targetBlock = StoreStackForOffset(targetILOffset, currentStack);
Debug.Assert(currentBlock != null);
currentBlock.OutgoingEdges.Add((targetBlock, currentStack));
}
/// <summary>
/// The expression stack holds ILInstructions that might have side-effects
/// that should have already happened (in the order of the pushes).
/// This method forces these instructions to be added to the instructionBuilder.
/// This is used e.g. to avoid moving side-effects past branches.
/// </summary>
private void FlushExpressionStack()
{
Debug.Assert(currentBlock != null);
foreach (var inst in expressionStack)
{
Debug.Assert(inst.ResultType != StackType.Void);
IType type = compilation.FindType(inst.ResultType);
var v = new ILVariable(VariableKind.StackSlot, type, inst.ResultType);
v.HasGeneratedName = true;
currentStack = currentStack.Push(v);
currentBlock.Block.Instructions.Add(new StLoc(v, inst).WithILRange(inst));
}
expressionStack.Clear();
}
ILInstruction DecodeSwitch()
{
var targets = ILParser.DecodeSwitchTargets(ref reader);
var instr = new SwitchInstruction(Pop(StackType.I4));
for (int i = 0; i < targets.Length; i++)
{
var section = new SwitchSection();
section.Labels = new LongSet(i);
int target = targets[i];
if (!IsInvalidBranch(target))
{
MarkBranchTarget(target);
section.Body = new Branch(target);
}
else
{
section.Body = new InvalidBranch("Invalid branch target");
}
instr.Sections.Add(section);
}
var defaultSection = new SwitchSection();
defaultSection.Labels = new LongSet(new LongInterval(0, targets.Length)).Invert();
defaultSection.Body = new Nop();
instr.Sections.Add(defaultSection);
return instr;
}
DecodedInstruction BinaryNumeric(BinaryNumericOperator @operator, bool checkForOverflow = false, Sign sign = Sign.None)
{
var right = Pop();
var left = Pop();
// left will run before right, thus preserving the evaluation order
if (@operator != BinaryNumericOperator.Add && @operator != BinaryNumericOperator.Sub)
{
// we are treating all Refs as I, make the conversion explicit
if (left.ResultType == StackType.Ref)
{
left = new Conv(left, PrimitiveType.I, false, Sign.None);
}
if (right.ResultType == StackType.Ref)
{
right = new Conv(right, PrimitiveType.I, false, Sign.None);
}
}
if (@operator != BinaryNumericOperator.ShiftLeft && @operator != BinaryNumericOperator.ShiftRight)
{
// make the implicit I4->I conversion explicit:
MakeExplicitConversion(sourceType: StackType.I4, targetType: StackType.I, conversionType: PrimitiveType.I);
// I4->I8 conversion:
MakeExplicitConversion(sourceType: StackType.I4, targetType: StackType.I8, conversionType: PrimitiveType.I8);
// I->I8 conversion:
MakeExplicitConversion(sourceType: StackType.I, targetType: StackType.I8, conversionType: PrimitiveType.I8);
// F4->F8 conversion:
MakeExplicitConversion(sourceType: StackType.F4, targetType: StackType.F8, conversionType: PrimitiveType.R8);
}
return Push(new BinaryNumericInstruction(@operator, left, right, checkForOverflow, sign));
void MakeExplicitConversion(StackType sourceType, StackType targetType, PrimitiveType conversionType)
{
if (left.ResultType == sourceType && right.ResultType == targetType)
{
left = new Conv(left, conversionType, false, Sign.None);
}
else if (left.ResultType == targetType && right.ResultType == sourceType)
{
right = new Conv(right, conversionType, false, Sign.None);
}
}
}
ILInstruction DecodeJmp()
{
IMethod method = ReadAndDecodeMethodReference();
// Translate jmp into tail call:
Call call = new Call(method);
call.IsTail = true;
call.ILStackWasEmpty = true;
if (!method.IsStatic)
{
call.Arguments.Add(Ldarg(0));
}
foreach (var p in method.Parameters)
{
call.Arguments.Add(Ldarg(call.Arguments.Count));
}
return new Leave(mainContainer, call);
}
ILInstruction LdToken(EntityHandle token)
{
if (token.Kind.IsTypeKind())
return new LdTypeToken(module.ResolveType(token, genericContext));
if (token.Kind.IsMemberKind())
{
var entity = module.ResolveEntity(token, genericContext);
if (entity is IMember member)
return new LdMemberToken(member);
}
throw new BadImageFormatException("Invalid metadata token for ldtoken instruction.");
}
}
}