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// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
//
// 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.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using ICSharpCode.Decompiler;
using ICSharpCode.Decompiler.FlowAnalysis;
using ICSharpCode.Decompiler.ILAst;
using Mono.Cecil;
using Mono.Cecil.Cil;
namespace ICSharpCode.Decompiler.Disassembler
{
/// <summary>
/// Disassembles a method body.
/// </summary>
public sealed class MethodBodyDisassembler
{
readonly ITextOutput output;
readonly bool detectControlStructure;
readonly CancellationToken cancellationToken;
public MethodBodyDisassembler(ITextOutput output, bool detectControlStructure, CancellationToken cancellationToken)
{
if (output == null)
throw new ArgumentNullException("output");
this.output = output;
this.detectControlStructure = detectControlStructure;
this.cancellationToken = cancellationToken;
}
public void Disassemble(MethodBody body, MethodDebugSymbols debugSymbols)
{
// start writing IL code
MethodDefinition method = body.Method;
output.WriteLine("// Method begins at RVA 0x{0:x4}", method.RVA);
output.WriteLine("// Code size {0} (0x{0:x})", body.CodeSize);
output.WriteLine(".maxstack {0}", body.MaxStackSize);
if (method.DeclaringType.Module.Assembly != null && method.DeclaringType.Module.Assembly.EntryPoint == method)
output.WriteLine (".entrypoint");
if (method.Body.HasVariables) {
output.Write(".locals ");
if (method.Body.InitLocals)
output.Write("init ");
output.WriteLine("(");
output.Indent();
foreach (var v in method.Body.Variables) {
output.WriteDefinition("[" + v.Index + "] ", v);
v.VariableType.WriteTo(output);
if (!string.IsNullOrEmpty(v.Name)) {
output.Write(' ');
output.Write(DisassemblerHelpers.Escape(v.Name));
}
if (v.Index + 1 < method.Body.Variables.Count)
output.Write(',');
output.WriteLine();
}
output.Unindent();
output.WriteLine(")");
}
output.WriteLine();
if (detectControlStructure && body.Instructions.Count > 0) {
Instruction inst = body.Instructions[0];
HashSet<int> branchTargets = GetBranchTargets(body.Instructions);
WriteStructureBody(new ILStructure(body), branchTargets, ref inst, debugSymbols, method.Body.CodeSize);
} else {
foreach (var inst in method.Body.Instructions) {
var startLocation = output.Location;
inst.WriteTo(output);
if (debugSymbols != null) {
// add IL code mappings - used in debugger
debugSymbols.SequencePoints.Add(
new SequencePoint() {
StartLocation = output.Location,
EndLocation = output.Location,
ILRanges = new ILRange[] { new ILRange(inst.Offset, inst.Next == null ? method.Body.CodeSize : inst.Next.Offset) }
});
}
output.WriteLine();
}
if (method.Body.HasExceptionHandlers) {
output.WriteLine();
foreach (var eh in method.Body.ExceptionHandlers) {
eh.WriteTo(output);
output.WriteLine();
}
}
}
}
HashSet<int> GetBranchTargets(IEnumerable<Instruction> instructions)
{
HashSet<int> branchTargets = new HashSet<int>();
foreach (var inst in instructions) {
Instruction target = inst.Operand as Instruction;
if (target != null)
branchTargets.Add(target.Offset);
Instruction[] targets = inst.Operand as Instruction[];
if (targets != null)
foreach (Instruction t in targets)
branchTargets.Add(t.Offset);
}
return branchTargets;
}
void WriteStructureHeader(ILStructure s)
{
switch (s.Type) {
case ILStructureType.Loop:
output.Write("// loop start");
if (s.LoopEntryPoint != null) {
output.Write(" (head: ");
DisassemblerHelpers.WriteOffsetReference(output, s.LoopEntryPoint);
output.Write(')');
}
output.WriteLine();
break;
case ILStructureType.Try:
output.WriteLine(".try");
output.WriteLine("{");
break;
case ILStructureType.Handler:
switch (s.ExceptionHandler.HandlerType) {
case ExceptionHandlerType.Catch:
case ExceptionHandlerType.Filter:
output.Write("catch");
if (s.ExceptionHandler.CatchType != null) {
output.Write(' ');
s.ExceptionHandler.CatchType.WriteTo(output, ILNameSyntax.TypeName);
}
output.WriteLine();
break;
case ExceptionHandlerType.Finally:
output.WriteLine("finally");
break;
case ExceptionHandlerType.Fault:
output.WriteLine("fault");
break;
default:
throw new NotSupportedException();
}
output.WriteLine("{");
break;
case ILStructureType.Filter:
output.WriteLine("filter");
output.WriteLine("{");
break;
default:
throw new NotSupportedException();
}
output.Indent();
}
void WriteStructureBody(ILStructure s, HashSet<int> branchTargets, ref Instruction inst, MethodDebugSymbols debugSymbols, int codeSize)
{
bool isFirstInstructionInStructure = true;
bool prevInstructionWasBranch = false;
int childIndex = 0;
while (inst != null && inst.Offset < s.EndOffset) {
int offset = inst.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 inst, debugSymbols, codeSize);
WriteStructureFooter(child);
} else {
if (!isFirstInstructionInStructure && (prevInstructionWasBranch || branchTargets.Contains(offset))) {
output.WriteLine(); // put an empty line after branches, and in front of branch targets
}
var startLocation = output.Location;
inst.WriteTo(output);
// add IL code mappings - used in debugger
if (debugSymbols != null) {
debugSymbols.SequencePoints.Add(
new SequencePoint() {
StartLocation = startLocation,
EndLocation = output.Location,
ILRanges = new ILRange[] { new ILRange(inst.Offset, inst.Next == null ? codeSize : inst.Next.Offset) }
});
}
output.WriteLine();
prevInstructionWasBranch = inst.OpCode.FlowControl == FlowControl.Branch
|| inst.OpCode.FlowControl == FlowControl.Cond_Branch
|| inst.OpCode.FlowControl == FlowControl.Return
|| inst.OpCode.FlowControl == FlowControl.Throw;
inst = inst.Next;
}
isFirstInstructionInStructure = false;
}
}
void WriteStructureFooter(ILStructure s)
{
output.Unindent();
switch (s.Type) {
case ILStructureType.Loop:
output.WriteLine("// end loop");
break;
case ILStructureType.Try:
output.WriteLine("} // end .try");
break;
case ILStructureType.Handler:
output.WriteLine("} // end handler");
break;
case ILStructureType.Filter:
output.WriteLine("} // end filter");
break;
default:
throw new NotSupportedException();
}
}
}
}
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