void WriteStructureBody(ILStructure s, HashSet <int> branchTargets, ref BlobReader body)
{
bool isFirstInstructionInStructure = true;
bool prevInstructionWasBranch = false;
int childIndex = 0;
while (body.RemainingBytes > 0 && body.Offset < s.EndOffset)
{
int offset = body.Offset;
if (childIndex < s.Children.Count && s.Children[childIndex].StartOffset <= offset && offset < s.Children[childIndex].EndOffset)
{
ILStructure child = s.Children[childIndex++];
WriteStructureHeader(child);
WriteStructureBody(child, branchTargets, ref body);
WriteStructureFooter(child);
}
else
{
if (!isFirstInstructionInStructure && (prevInstructionWasBranch || branchTargets.Contains(offset)))
{
output.WriteLine(); // put an empty line after branches, and in front of branch targets
}
var currentOpCode = ILParser.DecodeOpCode(ref body);
body.Offset = offset; // reset IL stream
WriteInstruction(output, metadata, s.MethodHandle, ref body);
prevInstructionWasBranch = currentOpCode.IsBranch() ||
currentOpCode.IsReturn() ||
currentOpCode == ILOpCode.Throw ||
currentOpCode == ILOpCode.Rethrow ||
currentOpCode == ILOpCode.Switch;
}
isFirstInstructionInStructure = false;
}
}
void WriteRVA(BlobReader blob, int offset, ILOpCode opCode)
{
if (ShowRawRVAOffsetAndBytes)
{
output.Write("/* ");
var tmp = blob;
if (opCode == ILOpCode.Switch)
{
tmp.ReadInt32();
}
else
{
ILParser.SkipOperand(ref tmp, opCode);
}
output.Write($"0x{offset:X8} {(ushort)opCode:X2}");
int appendSpaces = (ushort)opCode > 0xFF ? 14 : 16;
while (blob.Offset < tmp.Offset)
{
output.Write($"{blob.ReadByte():X2}");
appendSpaces -= 2;
}
if (appendSpaces > 0)
{
output.Write(new string(' ', appendSpaces));
}
output.Write(" */ ");
}
}
HashSet <int> GetBranchTargets(BlobReader blob)
{
HashSet <int> branchTargets = new HashSet <int>();
while (blob.RemainingBytes > 0)
{
var opCode = ILParser.DecodeOpCode(ref blob);
if (opCode == ILOpCode.Switch)
{
branchTargets.UnionWith(ILParser.DecodeSwitchTargets(ref blob));
}
else if (opCode.IsBranch())
{
branchTargets.Add(ILParser.DecodeBranchTarget(ref blob, opCode));
}
else
{
ILParser.SkipOperand(ref blob, opCode);
}
}
return(branchTargets);
}
protected virtual void WriteInstruction(ITextOutput output, MetadataReader metadata, MethodDefinitionHandle methodDefinition, ref BlobReader blob)
{
int offset = blob.Offset;
if (ShowSequencePoints && nextSequencePointIndex < sequencePoints?.Count)
{
var sp = sequencePoints[nextSequencePointIndex];
if (sp.Offset <= offset)
{
output.Write("// sequence point: ");
if (sp.Offset != offset)
{
output.Write("!! at " + DisassemblerHelpers.OffsetToString(sp.Offset) + " !!");
}
if (sp.IsHidden)
{
output.WriteLine("hidden");
}
else
{
output.WriteLine($"(line {sp.StartLine}, col {sp.StartColumn}) to (line {sp.EndLine}, col {sp.EndColumn}) in {sp.DocumentUrl}");
}
nextSequencePointIndex++;
}
}
ILOpCode opCode = ILParser.DecodeOpCode(ref blob);
output.WriteLocalReference(DisassemblerHelpers.OffsetToString(offset), offset, isDefinition: true);
output.Write(": ");
if (opCode.IsDefined())
{
output.WriteReference(new OpCodeInfo(opCode, opCode.GetDisplayName()));
switch (opCode.GetOperandType())
{
case OperandType.BrTarget:
case OperandType.ShortBrTarget:
output.Write(' ');
int targetOffset = ILParser.DecodeBranchTarget(ref blob, opCode);
output.WriteLocalReference($"IL_{targetOffset:x4}", targetOffset);
break;
case OperandType.Field:
case OperandType.Method:
case OperandType.Sig:
case OperandType.Type:
output.Write(' ');
int metadataToken = blob.ReadInt32();
EntityHandle?handle = MetadataTokenHelpers.TryAsEntityHandle(metadataToken);
try {
handle?.WriteTo(module, output, genericContext);
} catch (BadImageFormatException) {
handle = null;
}
WriteMetadataToken(handle, metadataToken, spaceBefore: true);
break;
case OperandType.Tok:
output.Write(' ');
metadataToken = blob.ReadInt32();
handle = MetadataTokenHelpers.TryAsEntityHandle(metadataToken);
switch (handle?.Kind)
{
case HandleKind.MemberReference:
switch (metadata.GetMemberReference((MemberReferenceHandle)handle).GetKind())
{
case MemberReferenceKind.Method:
output.Write("method ");
break;
case MemberReferenceKind.Field:
output.Write("field ");
break;
}
break;
case HandleKind.FieldDefinition:
output.Write("field ");
break;
case HandleKind.MethodDefinition:
output.Write("method ");
break;
}
try {
handle?.WriteTo(module, output, genericContext);
} catch (BadImageFormatException) {
handle = null;
}
WriteMetadataToken(handle, metadataToken, spaceBefore: true);
break;
case OperandType.ShortI:
output.Write(' ');
DisassemblerHelpers.WriteOperand(output, blob.ReadSByte());
break;
case OperandType.I:
output.Write(' ');
DisassemblerHelpers.WriteOperand(output, blob.ReadInt32());
break;
case OperandType.I8:
output.Write(' ');
DisassemblerHelpers.WriteOperand(output, blob.ReadInt64());
break;
case OperandType.ShortR:
output.Write(' ');
DisassemblerHelpers.WriteOperand(output, blob.ReadSingle());
break;
case OperandType.R:
output.Write(' ');
DisassemblerHelpers.WriteOperand(output, blob.ReadDouble());
break;
case OperandType.String:
metadataToken = blob.ReadInt32();
output.Write(' ');
UserStringHandle?userString;
string text;
try {
userString = MetadataTokens.UserStringHandle(metadataToken);
text = metadata.GetUserString(userString.Value);
} catch (BadImageFormatException) {
userString = null;
text = null;
}
if (userString != null)
{
DisassemblerHelpers.WriteOperand(output, text);
}
WriteMetadataToken(userString, metadataToken, spaceBefore: true);
break;
case OperandType.Switch:
int[] targets = ILParser.DecodeSwitchTargets(ref blob);
output.Write(" (");
for (int i = 0; i < targets.Length; i++)
{
if (i > 0)
{
output.Write(", ");
}
output.WriteLocalReference($"IL_{targets[i]:x4}", targets[i]);
}
output.Write(")");
break;
case OperandType.Variable:
output.Write(' ');
int index = blob.ReadUInt16();
if (opCode == ILOpCode.Ldloc || opCode == ILOpCode.Ldloca || opCode == ILOpCode.Stloc)
{
DisassemblerHelpers.WriteVariableReference(output, metadata, methodDefinition, index);
}
else
{
DisassemblerHelpers.WriteParameterReference(output, metadata, methodDefinition, index);
}
break;
case OperandType.ShortVariable:
output.Write(' ');
index = blob.ReadByte();
if (opCode == ILOpCode.Ldloc_s || opCode == ILOpCode.Ldloca_s || opCode == ILOpCode.Stloc_s)
{
DisassemblerHelpers.WriteVariableReference(output, metadata, methodDefinition, index);
}
else
{
DisassemblerHelpers.WriteParameterReference(output, metadata, methodDefinition, index);
}
break;
}
}
else
{
ushort opCodeValue = (ushort)opCode;
if (opCodeValue > 0xFF)
{
// split 16-bit value into two emitbyte directives
output.WriteLine($".emitbyte 0x{(byte)(opCodeValue >> 8):x}");
// add label
output.WriteLocalReference(DisassemblerHelpers.OffsetToString(offset + 1), offset + 1, isDefinition: true);
output.Write(": ");
output.Write($".emitbyte 0x{(byte)(opCodeValue & 0xFF):x}");
}
else
{
output.Write($".emitbyte 0x{(byte)opCodeValue:x}");
}
}
output.WriteLine();
}
public virtual void Disassemble(PEFile module, MethodDefinitionHandle handle)
{
this.module = module ?? throw new ArgumentNullException(nameof(module));
metadata = module.Metadata;
genericContext = new GenericContext(handle, module);
signatureDecoder = new DisassemblerSignatureTypeProvider(module, output);
var methodDefinition = metadata.GetMethodDefinition(handle);
// start writing IL code
output.WriteLine("// Method begins at RVA 0x{0:x4}", methodDefinition.RelativeVirtualAddress);
if (methodDefinition.RelativeVirtualAddress == 0)
{
output.WriteLine("// Header size: {0}", 0);
output.WriteLine("// Code size: {0} (0x{0:x})", 0);
output.WriteLine(".maxstack {0}", 0);
output.WriteLine();
return;
}
MethodBodyBlock body;
BlobReader bodyBlockReader;
try
{
body = module.Reader.GetMethodBody(methodDefinition.RelativeVirtualAddress);
bodyBlockReader = module.Reader.GetSectionData(methodDefinition.RelativeVirtualAddress).GetReader();
}
catch (BadImageFormatException ex)
{
output.WriteLine("// {0}", ex.Message);
return;
}
var blob = body.GetILReader();
int headerSize = ILParser.GetHeaderSize(bodyBlockReader);
output.WriteLine("// Header size: {0}", headerSize);
output.WriteLine("// Code size: {0} (0x{0:x})", blob.Length);
output.WriteLine(".maxstack {0}", body.MaxStack);
var entrypointHandle = MetadataTokens.MethodDefinitionHandle(module.Reader.PEHeaders.CorHeader.EntryPointTokenOrRelativeVirtualAddress);
if (handle == entrypointHandle)
{
output.WriteLine(".entrypoint");
}
DisassembleLocalsBlock(handle, body);
output.WriteLine();
sequencePoints = DebugInfo?.GetSequencePoints(handle) ?? EmptyList <DebugInfo.SequencePoint> .Instance;
nextSequencePointIndex = 0;
if (DetectControlStructure && blob.Length > 0)
{
blob.Reset();
HashSet <int> branchTargets = GetBranchTargets(blob);
blob.Reset();
WriteStructureBody(new ILStructure(module, handle, genericContext, body), branchTargets, ref blob, methodDefinition.RelativeVirtualAddress + headerSize);
}
else
{
while (blob.RemainingBytes > 0)
{
cancellationToken.ThrowIfCancellationRequested();
WriteInstruction(output, metadata, handle, ref blob, methodDefinition.RelativeVirtualAddress);
}
WriteExceptionHandlers(module, handle, body);
}
sequencePoints = null;
}
