internal InstructionParser(SourceMethodBody sourceMethodBody) {
      Contract.Requires(sourceMethodBody != null);

      this.sourceMethodBody = sourceMethodBody;
      this.host = sourceMethodBody.host; Contract.Assume(this.host != null);
      this.ilMethodBody = sourceMethodBody.ilMethodBody; Contract.Assume(this.ilMethodBody != null);
      this.MethodDefinition = sourceMethodBody.MethodDefinition;
      this.nameTable = sourceMethodBody.nameTable; Contract.Assume(this.nameTable != null);
      this.sourceLocationProvider = sourceMethodBody.sourceLocationProvider;
      this.localScopeProvider = sourceMethodBody.localScopeProvider;
      this.options = sourceMethodBody.options;
      this.platformType = sourceMethodBody.platformType; Contract.Assume(this.platformType != null);
      this.numberOfAssignmentsToLocal = sourceMethodBody.numberOfAssignmentsToLocal; Contract.Assume(this.numberOfAssignmentsToLocal != null);
      this.numberOfReferencesToLocal = sourceMethodBody.numberOfReferencesToLocal; Contract.Assume(this.numberOfReferencesToLocal != null);
      this.gotosThatTarget = sourceMethodBody.gotosThatTarget; Contract.Assume(this.gotosThatTarget != null);
      this.cdfg = sourceMethodBody.cdfg; Contract.Assume(this.cdfg != null);
      this.bindingsThatMakeALastUseOfALocalVersion = sourceMethodBody.bindingsThatMakeALastUseOfALocalVersion; Contract.Assume(this.bindingsThatMakeALastUseOfALocalVersion != null);

      if (this.localScopeProvider != null) {
        var syncInfo = this.localScopeProvider.GetSynchronizationInformation(sourceMethodBody);
        if (syncInfo != null) {
          var syncPointFor = this.synchronizatonPointLocationFor = new Hashtable<SynchronizationPointLocation>();
          IDocument doc = Dummy.Document;
          foreach (var loc in this.MethodDefinition.Locations) { doc = loc.Document; break; }
          foreach (var syncPoint in syncInfo.SynchronizationPoints) {
            Contract.Assume(syncPoint != null);
            var syncLoc = new SynchronizationPointLocation(doc, syncPoint);
            syncPointFor[syncPoint.SynchronizeOffset] = syncLoc;
            if (syncPoint.ContinuationMethod == null)
              syncPointFor[syncPoint.ContinuationOffset] = syncLoc;
          }
        }
      }
    }
    private void ParseInstruction(Instruction instruction, List<IStatement> statements) {
      Contract.Requires(instruction != null);
      Contract.Requires(statements != null);
      Statement/*?*/ statement = null;
      Expression/*?*/ expression = null;
      ITypeReference/*?*/ elementType = null;
      IOperation currentOperation = instruction.Operation;
      OperationCode currentOpcode = currentOperation.OperationCode;
      if (this.host.PreserveILLocations) {
        if (this.lastLocation == null)
          this.lastLocation = currentOperation.Location;
      } else if (this.sourceLocationProvider != null) {
        if (this.lastSourceLocation == null) {
          foreach (var sourceLocation in this.sourceLocationProvider.GetPrimarySourceLocationsFor(currentOperation.Location)) {
            Contract.Assume(sourceLocation != null);
            if (sourceLocation.StartLine != 0x00feefee) {
              this.lastSourceLocation = sourceLocation;
              break;
            }
          }
        }
      }
      if (this.synchronizatonPointLocationFor != null) {
        uint currentOffset = currentOperation.Offset;
        var syncPointLocation = this.synchronizatonPointLocationFor[currentOffset];
        if (syncPointLocation != null) {
          if (syncPointLocation.SynchronizationPoint.ContinuationOffset == currentOffset)
            this.lastContinuationLocation = new ContinuationLocation(syncPointLocation);
          else
            this.lastSynchronizationLocation = syncPointLocation;
        }
      }
      switch (currentOpcode) {
        case OperationCode.Add:
        case OperationCode.Add_Ovf:
        case OperationCode.Add_Ovf_Un:
        case OperationCode.And:
        case OperationCode.Ceq:
        case OperationCode.Cgt:
        case OperationCode.Cgt_Un:
        case OperationCode.Clt:
        case OperationCode.Clt_Un:
        case OperationCode.Div:
        case OperationCode.Div_Un:
        case OperationCode.Mul:
        case OperationCode.Mul_Ovf:
        case OperationCode.Mul_Ovf_Un:
        case OperationCode.Or:
        case OperationCode.Rem:
        case OperationCode.Rem_Un:
        case OperationCode.Shl:
        case OperationCode.Shr:
        case OperationCode.Shr_Un:
        case OperationCode.Sub:
        case OperationCode.Sub_Ovf:
        case OperationCode.Sub_Ovf_Un:
        case OperationCode.Xor:
          expression = this.ParseBinaryOperation(currentOpcode);
          break;

        case OperationCode.Arglist:
          expression = new RuntimeArgumentHandleExpression();
          break;

        case OperationCode.Array_Addr:
          elementType = ((IArrayTypeReference)currentOperation.Value).ElementType;
          expression = this.ParseArrayElementAddres(currentOperation, elementType);
          break;

        case OperationCode.Ldelema:
          elementType = (ITypeReference)currentOperation.Value;
          expression = this.ParseArrayElementAddres(currentOperation, elementType, treatArrayAsSingleDimensioned: true);
          break;

        case OperationCode.Array_Create:
        case OperationCode.Array_Create_WithLowerBound:
        case OperationCode.Newarr:
          expression = this.ParseArrayCreate(currentOperation);
          break;

        case OperationCode.Array_Get:
          elementType = ((IArrayTypeReference)currentOperation.Value).ElementType;
          expression = this.ParseArrayIndexer(currentOperation, elementType??this.platformType.SystemObject, treatArrayAsSingleDimensioned: false);
          break;

        case OperationCode.Ldelem:
          elementType = (ITypeReference)currentOperation.Value;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_I:
          elementType = this.platformType.SystemIntPtr;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_I1:
          elementType = this.platformType.SystemInt8;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_I2:
          elementType = this.platformType.SystemInt16;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_I4:
          elementType = this.platformType.SystemInt32;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_I8:
          elementType = this.platformType.SystemInt64;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_R4:
          elementType = this.platformType.SystemFloat32;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_R8:
          elementType = this.platformType.SystemFloat64;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_U1:
          elementType = this.platformType.SystemUInt8;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_U2:
          elementType = this.platformType.SystemUInt16;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_U4:
          elementType = this.platformType.SystemUInt32;
          goto case OperationCode.Ldelem_Ref;
        case OperationCode.Ldelem_Ref:
          expression = this.ParseArrayIndexer(currentOperation, elementType??this.platformType.SystemObject, treatArrayAsSingleDimensioned: true);
          break;

        case OperationCode.Array_Set:
          statement = this.ParseArraySet(currentOperation);
          break;

        case OperationCode.Beq:
        case OperationCode.Beq_S:
        case OperationCode.Bge:
        case OperationCode.Bge_S:
        case OperationCode.Bge_Un:
        case OperationCode.Bge_Un_S:
        case OperationCode.Bgt:
        case OperationCode.Bgt_S:
        case OperationCode.Bgt_Un:
        case OperationCode.Bgt_Un_S:
        case OperationCode.Ble:
        case OperationCode.Ble_S:
        case OperationCode.Ble_Un:
        case OperationCode.Ble_Un_S:
        case OperationCode.Blt:
        case OperationCode.Blt_S:
        case OperationCode.Blt_Un:
        case OperationCode.Blt_Un_S:
        case OperationCode.Bne_Un:
        case OperationCode.Bne_Un_S:
          statement = this.ParseBinaryConditionalBranch(currentOperation);
          break;

        case OperationCode.Box:
          expression = this.ParseConversion(currentOperation);
          break;

        case OperationCode.Br:
        case OperationCode.Br_S:
        case OperationCode.Leave:
        case OperationCode.Leave_S:
          statement = this.ParseUnconditionalBranch(currentOperation);
          break;

        case OperationCode.Break:
          statement = new DebuggerBreakStatement();
          break;

        case OperationCode.Brfalse:
        case OperationCode.Brfalse_S:
        case OperationCode.Brtrue:
        case OperationCode.Brtrue_S:
          statement = this.ParseUnaryConditionalBranch(currentOperation);
          break;

        case OperationCode.Call:
        case OperationCode.Callvirt:
          MethodCall call = this.ParseCall(currentOperation);
          if (call.MethodToCall.Type.TypeCode == PrimitiveTypeCode.Void) {
            call.Locations.Add(currentOperation.Location); // turning it into a statement prevents the location from being attached to the expresssion
            ExpressionStatement es = new ExpressionStatement();
            es.Expression = call;
            statement = es;
          } else
            expression = call;
          break;

        case OperationCode.Calli:
          expression = this.ParsePointerCall(currentOperation);
          break;

        case OperationCode.Castclass:
        case OperationCode.Conv_I:
        case OperationCode.Conv_I1:
        case OperationCode.Conv_I2:
        case OperationCode.Conv_I4:
        case OperationCode.Conv_I8:
        case OperationCode.Conv_Ovf_I:
        case OperationCode.Conv_Ovf_I_Un:
        case OperationCode.Conv_Ovf_I1:
        case OperationCode.Conv_Ovf_I1_Un:
        case OperationCode.Conv_Ovf_I2:
        case OperationCode.Conv_Ovf_I2_Un:
        case OperationCode.Conv_Ovf_I4:
        case OperationCode.Conv_Ovf_I4_Un:
        case OperationCode.Conv_Ovf_I8:
        case OperationCode.Conv_Ovf_I8_Un:
        case OperationCode.Conv_Ovf_U:
        case OperationCode.Conv_Ovf_U_Un:
        case OperationCode.Conv_Ovf_U1:
        case OperationCode.Conv_Ovf_U1_Un:
        case OperationCode.Conv_Ovf_U2:
        case OperationCode.Conv_Ovf_U2_Un:
        case OperationCode.Conv_Ovf_U4:
        case OperationCode.Conv_Ovf_U4_Un:
        case OperationCode.Conv_Ovf_U8:
        case OperationCode.Conv_Ovf_U8_Un:
        case OperationCode.Conv_R_Un:
        case OperationCode.Conv_R4:
        case OperationCode.Conv_R8:
        case OperationCode.Conv_U:
        case OperationCode.Conv_U1:
        case OperationCode.Conv_U2:
        case OperationCode.Conv_U4:
        case OperationCode.Conv_U8:
        case OperationCode.Unbox:
        case OperationCode.Unbox_Any:
          expression = this.ParseConversion(currentOperation);
          break;

        case OperationCode.Ckfinite:
          var operand = this.PopOperandStack();
          var chkfinite = new MutableCodeModel.MethodReference() {
            CallingConvention = Cci.CallingConvention.FastCall,
            ContainingType = host.PlatformType.SystemFloat64,
            Name = this.host.NameTable.GetNameFor("__ckfinite__"),
            Type = host.PlatformType.SystemFloat64,
            InternFactory = host.InternFactory,
          };
          expression = new MethodCall() { Arguments = new List<IExpression>(1) { operand }, IsStaticCall = true, Type = operand.Type, MethodToCall = chkfinite };
          break;

        case OperationCode.Constrained_:
          //This prefix is redundant and is not represented in the code model.
          break;

        case OperationCode.Cpblk:
          var copyMemory = new CopyMemoryStatement();
          copyMemory.NumberOfBytesToCopy = this.PopOperandStack();
          copyMemory.SourceAddress = this.PopOperandStack();
          copyMemory.TargetAddress = this.PopOperandStack();
          statement = copyMemory;
          break;

        case OperationCode.Cpobj:
          expression = this.ParseCopyObject();
          break;

        case OperationCode.Dup:
          expression = this.ParseDup(instruction.Type);
          break;

        case OperationCode.Endfilter:
          statement = this.ParseEndfilter();
          break;

        case OperationCode.Endfinally:
          statement = new EndFinally();
          break;

        case OperationCode.Initblk:
          var fillMemory = new FillMemoryStatement();
          fillMemory.NumberOfBytesToFill = this.PopOperandStack();
          fillMemory.FillValue = this.PopOperandStack();
          fillMemory.TargetAddress = this.PopOperandStack();
          statement = fillMemory;
          break;

        case OperationCode.Initobj:
          statement = this.ParseInitObject(currentOperation);
          break;

        case OperationCode.Isinst:
          expression = this.ParseCastIfPossible(currentOperation);
          break;

        case OperationCode.Jmp:
          var methodToCall = (IMethodReference)currentOperation.Value;
          expression = new MethodCall() { IsJumpCall = true, MethodToCall = methodToCall, Type = methodToCall.Type };
          break;

        case OperationCode.Ldarg:
        case OperationCode.Ldarg_0:
        case OperationCode.Ldarg_1:
        case OperationCode.Ldarg_2:
        case OperationCode.Ldarg_3:
        case OperationCode.Ldarg_S:
        case OperationCode.Ldloc:
        case OperationCode.Ldloc_0:
        case OperationCode.Ldloc_1:
        case OperationCode.Ldloc_2:
        case OperationCode.Ldloc_3:
        case OperationCode.Ldloc_S:
        case OperationCode.Ldfld:
        case OperationCode.Ldsfld:
          expression = this.ParseBoundExpression(instruction);
          break;

        case OperationCode.Ldarga:
        case OperationCode.Ldarga_S:
        case OperationCode.Ldflda:
        case OperationCode.Ldsflda:
        case OperationCode.Ldloca:
        case OperationCode.Ldloca_S:
        case OperationCode.Ldftn:
        case OperationCode.Ldvirtftn:
          expression = this.ParseAddressOf(instruction);
          break;

        case OperationCode.Ldc_I4:
        case OperationCode.Ldc_I4_0:
        case OperationCode.Ldc_I4_1:
        case OperationCode.Ldc_I4_2:
        case OperationCode.Ldc_I4_3:
        case OperationCode.Ldc_I4_4:
        case OperationCode.Ldc_I4_5:
        case OperationCode.Ldc_I4_6:
        case OperationCode.Ldc_I4_7:
        case OperationCode.Ldc_I4_8:
        case OperationCode.Ldc_I4_M1:
        case OperationCode.Ldc_I4_S:
        case OperationCode.Ldc_I8:
        case OperationCode.Ldc_R4:
        case OperationCode.Ldc_R8:
        case OperationCode.Ldnull:
        case OperationCode.Ldstr:
          expression = this.ParseCompileTimeConstant(currentOperation);
          break;

        case OperationCode.Ldind_I:
        case OperationCode.Ldind_I1:
        case OperationCode.Ldind_I2:
        case OperationCode.Ldind_I4:
        case OperationCode.Ldind_I8:
        case OperationCode.Ldind_R4:
        case OperationCode.Ldind_R8:
        case OperationCode.Ldind_Ref:
        case OperationCode.Ldind_U1:
        case OperationCode.Ldind_U2:
        case OperationCode.Ldind_U4:
        case OperationCode.Ldobj:
          expression = this.ParseAddressDereference(currentOperation);
          break;

        case OperationCode.Ldlen:
          expression = this.ParseVectorLength();
          break;

        case OperationCode.Ldtoken:
          expression = ParseToken(currentOperation);
          break;

        case OperationCode.Localloc:
          expression = this.ParseStackArrayCreate();
          break;

        case OperationCode.Mkrefany:
          expression = this.ParseMakeTypedReference(currentOperation);
          break;

        case OperationCode.Neg:
          expression = this.ParseUnaryOperation(new UnaryNegation());
          break;

        case OperationCode.Not:
          expression = this.ParseUnaryOperation(new OnesComplement());
          break;

        case OperationCode.Newobj:
          expression = this.ParseCreateObjectInstance(currentOperation);
          break;

        case OperationCode.No_:
          Contract.Assume(false); //if code out there actually uses this, I need to know sooner rather than later.
          //TODO: need object model support
          break;

        case OperationCode.Nop:
          statement = new EmptyStatement();
          break;

        case OperationCode.Pop:
          statement = this.ParsePop();
          break;

        case OperationCode.Readonly_:
          this.sawReadonly = true;
          break;

        case OperationCode.Refanytype:
          expression = this.ParseGetTypeOfTypedReference();
          break;

        case OperationCode.Refanyval:
          expression = this.ParseGetValueOfTypedReference(currentOperation);
          break;

        case OperationCode.Ret:
          statement = this.ParseReturn();
          break;

        case OperationCode.Rethrow:
          statement = new RethrowStatement();
          break;

        case OperationCode.Sizeof:
          expression = ParseSizeOf(currentOperation);
          break;

        case OperationCode.Starg:
        case OperationCode.Starg_S:
        case OperationCode.Stelem:
        case OperationCode.Stelem_I:
        case OperationCode.Stelem_I1:
        case OperationCode.Stelem_I2:
        case OperationCode.Stelem_I4:
        case OperationCode.Stelem_I8:
        case OperationCode.Stelem_R4:
        case OperationCode.Stelem_R8:
        case OperationCode.Stelem_Ref:
        case OperationCode.Stfld:
        case OperationCode.Stind_I:
        case OperationCode.Stind_I1:
        case OperationCode.Stind_I2:
        case OperationCode.Stind_I4:
        case OperationCode.Stind_I8:
        case OperationCode.Stind_R4:
        case OperationCode.Stind_R8:
        case OperationCode.Stind_Ref:
        case OperationCode.Stloc:
        case OperationCode.Stloc_0:
        case OperationCode.Stloc_1:
        case OperationCode.Stloc_2:
        case OperationCode.Stloc_3:
        case OperationCode.Stloc_S:
        case OperationCode.Stobj:
        case OperationCode.Stsfld:
          statement = this.ParseAssignment(currentOperation);
          break;

        case OperationCode.Switch:
          statement = this.ParseSwitchInstruction(currentOperation);
          break;

        case OperationCode.Tail_:
          this.sawTailCall = true;
          break;

        case OperationCode.Throw:
          statement = this.ParseThrow();
          break;

        case OperationCode.Unaligned_:
          Contract.Assume(currentOperation.Value is byte);
          var alignment = (byte)currentOperation.Value;
          Contract.Assume(alignment == 1 || alignment == 2 || alignment == 4);
          this.alignment = alignment;
          break;

        case OperationCode.Volatile_:
          this.sawVolatile = true;
          break;

      }
      if (expression != null) {
        if (expression.Type is Dummy)
          expression.Type = instruction.Type;
        Contract.Assume(!(expression.Type is Dummy));
        if (expression.Type.TypeCode != PrimitiveTypeCode.Void) {
          if (this.host.PreserveILLocations) {
            expression.Locations.Add(currentOperation.Location);
          }
          this.operandStack.Push(expression);
        }
      } else if (statement != null) {
        this.TurnOperandStackIntoPushStatements(statements);
        statements.Add(statement);
        if (this.host.PreserveILLocations) {
          if (this.lastLocation != null) {
            statement.Locations.Add(this.lastLocation);
            this.lastLocation = null;
          }
        } else if (this.lastSourceLocation != null) {
          statement.Locations.Add(this.lastSourceLocation);
          this.lastSourceLocation = null;
        }
        if (this.lastSynchronizationLocation != null) {
          statement.Locations.Add(this.lastSynchronizationLocation);
          this.lastSynchronizationLocation = null;
        } else if (this.lastContinuationLocation != null) {
          statement.Locations.Add(this.lastContinuationLocation);
          this.lastContinuationLocation = null;
        }
      }
    }