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//
// Decompile.cs
//
// Authors:
// Chris Bacon (chrisbacon76@gmail.com)
//
// Copyright (C) 2010 Chris Bacon
//
// 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.Text;
using Mono.CodeContracts.Rewrite.Ast;
using Mono.Cecil;
using Mono.Cecil.Cil;
namespace Mono.CodeContracts.Rewrite {
class Decompile {
public Decompile (ModuleDefinition module, MethodDefinition method)
{
this.method = method;
this.exprs = new Stack<Expr> ();
this.Instructions = new Dictionary<Expr, Instruction> ();
this.methodInfo = new MethodInfo (module, method);
this.gen = new ExprGen (this.methodInfo);
}
private MethodInfo methodInfo;
private MethodDefinition method;
private Stack<Expr> exprs;
private ExprGen gen;
public Dictionary<Expr, Instruction> Instructions { get; private set; }
public Expr Go (bool failQuietly = true)
{
Instruction unknownInst = null;
var insts = this.method.Body.Instructions;
foreach (Instruction inst in insts) {
if (failQuietly) {
if (unknownInst == null) {
try {
Expr expr = this.ProcessInst (inst);
this.Instructions.Add (expr, inst);
this.exprs.Push (expr);
} catch (NotSupportedException) {
unknownInst = inst;
}
} else {
// Met unknown instruction, so check that there are no more contracts
if (inst.OpCode.OperandType == OperandType.InlineMethod) {
MethodReference method = (MethodReference) inst.Operand;
if (method.DeclaringType.FullName == "System.Diagnostics.Contracts.Contract") {
throw new NotSupportedException ("Unknown instruction in contract: " + unknownInst);
}
}
}
} else {
Expr expr = this.ProcessInst (inst);
this.Instructions.Add (expr, inst);
this.exprs.Push (expr);
}
}
Expr decompiled = new ExprBlock (this.methodInfo, this.exprs.Reverse ().ToArray ());
return decompiled;
}
private Expr ProcessInst (Instruction inst)
{
var opcode = inst.OpCode.Code;
switch (opcode) {
case Code.Nop:
return this.gen.Nop ();
case Code.Ldarg_0:
case Code.Ldarg_1:
case Code.Ldarg_2:
case Code.Ldarg_3:
return this.gen.LoadArg ((int) (opcode - Code.Ldarg_0));
case Code.Ldarg_S:
return this.gen.LoadArg ((ParameterDefinition) inst.Operand);
case Code.Ldnull:
return this.gen.LoadConstant (null);
case Code.Ldc_I4_M1:
case Code.Ldc_I4_0:
case Code.Ldc_I4_1:
case Code.Ldc_I4_2:
case Code.Ldc_I4_3:
case Code.Ldc_I4_4:
case Code.Ldc_I4_5:
case Code.Ldc_I4_6:
case Code.Ldc_I4_7:
case Code.Ldc_I4_8:
return this.gen.LoadConstant ((int) (opcode - Code.Ldc_I4_0));
case Code.Ldc_I4_S:
return this.gen.LoadConstant ((int) (sbyte) inst.Operand);
case Code.Ldc_I4:
return this.gen.LoadConstant ((int) inst.Operand);
case Code.Ldc_R4:
case Code.Ldc_R8:
case Code.Ldstr:
return this.gen.LoadConstant(inst.Operand);
case Code.Clt:
case Code.Clt_Un:
case Code.Cgt:
case Code.Cgt_Un:
case Code.Ceq:
case Code.Add:
case Code.Sub:
return this.ProcessBinaryOp (opcode);
case Code.Call:
return this.ProcessCall ((MethodReference) inst.Operand);
case Code.Ret:
return this.gen.Return ();
case Code.Conv_I4:
return this.ProcessConv (TypeCode.Int32);
case Code.Conv_I8:
return this.ProcessConv (TypeCode.Int64);
default:
throw new NotSupportedException ("Cannot handle opcode: " + inst.OpCode);
}
}
private Expr ProcessBinaryOp (Code opcode)
{
Expr right = this.exprs.Pop ();
Expr left = this.exprs.Pop ();
switch (opcode) {
case Code.Ceq:
return this.gen.CompareEqual (left, right);
case Code.Clt:
return this.gen.CompareLessThan (left, right, Sn.Signed);
case Code.Clt_Un:
return this.gen.CompareLessThan (left, right, Sn.Unsigned);
case Code.Cgt:
return this.gen.CompareGreaterThan (left, right, Sn.Signed);
case Code.Cgt_Un:
return this.gen.CompareGreaterThan (left, right, Sn.Unsigned);
case Code.Add:
return this.gen.Add (left, right, Sn.None, false);
case Code.Sub:
return this.gen.Sub (left, right, Sn.None, false);
default:
throw new NotSupportedException ("Unknown binary opcode: " + opcode);
}
}
private Expr ProcessCall (MethodReference method)
{
int paramCount = method.Parameters.Count;
Expr [] parameterExprs = new Expr [paramCount];
for (int i = 0; i < paramCount; i++) {
Expr parameter = this.exprs.Pop ();
parameterExprs [paramCount - i - 1] = parameter;
}
return this.gen.Call(method, parameterExprs);
}
private Expr ProcessConv (TypeCode convToType)
{
Expr exprToConvert = this.exprs.Pop ();
return this.gen.Conv(exprToConvert, convToType);
}
}
}
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