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Analysis of the compiled MSIL (Part 2)

, 8 Oct 2006
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Analysis of the MSIL generated by the .NET compiler for 4 Languages in VS 2005

Analysis compiled MSIL (Part 2)

This is a follow-up article to the (Analysis compiled MSIL (Part 1)) I thought I would explore the whole concept of how the compiler works, and what is generated by different languages. I thought I would explore how to optimize the code using the common objects provided by the .NET framework.

The Concept

The applications from the previous article were updated to make use of the .NET framework's StringBuilder class. This was primarily done to illustrate the efficiency of this class of performing string concatenations. It has often been suggested to use the string builder class to do string concatenation work, but I wondered whether anybody had actually seen the proof of efficiency this class offers.

Some additional optimization techniques followed in this article are to deal with the VB application. These techniques/tests include changing the default module, supplied by VS.NET to a class just to see if the compiler sees a difference between the two classes. I also changed a couple of the project settings.

  • Although not an optimization technique, but more of a test to see if there is actually any difference between classes and modules in the VB compiler, I decided to change the default declaration of Module1 from Module to Class
  • Removed integer overflow checks in Project properties compile tab(This can be found under advanced settings)
  • Switched Option Strict on

To really test these optimizations, I thought I would let both the methods run together, and print out to the console, the length of time each took to process just to compare how long each took. I thought I would also change one item in each of the old applications, and change the declarations of the "strSomeString" variable from supplying an empty quotes i.e "" to using the .NET framework's string.empty. This was primarily to see what was generated by the compiler.

The Code

VB

<code>Imports System.Diagnostics
Class Module1
    Shared Sub Main()
        Dim sbSomeString As New System.Text.StringBuilder
        Dim sw As New Stopwatch
        sw.Start()
        For i As Integer = 0 To 1000
            sbSomeString.Append("Test ")
        Next
        sw.Stop()
        Console.WriteLine(sbSomeString.ToString)
        Console.WriteLine("Time Taken :" & sw.ElapsedMilliseconds)
        OldCode()
    End Sub
    Shared Sub OldCode()
        Dim strSomeString As String = String.Empty
        Dim sw As New Stopwatch
        sw.Start()
        For i As Integer = 0 To 1000
            strSomeString += "Test "
        Next
        sw.Stop()
        Console.WriteLine(strSomeString)
        Console.WriteLine("Time Taken :" & sw.ElapsedMilliseconds)
        Console.ReadLine()
    End Sub
End Class

C#

<code>using System;
using System.Diagnostics;
namespace ConsoleCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            System.Text.StringBuilder sbSomeString = new System.Text.StringBuilder();
           Stopwatch sw = new Stopwatch();
            sw.Start();
            for (int i = 0; i < 1000; i++)
            {
               sbSomeString.Append("Test ");
            }
            sw.Stop();
            Console.WriteLine(sbSomeString.ToString());
            Console.WriteLine("Time Taken :" + sw.ElapsedMilliseconds);
            OldCode();
        }
        static void OldCode()
        {
            string strSomeString = string.Empty;
            Stopwatch sw = new Stopwatch();
            sw.Start();
            for (int i = 0; i < 1000; i++)
            {
                strSomeString += "Test ";
            }
            sw.Stop();
            Console.WriteLine(strSomeString);
            Console.WriteLine("Time Taken :" + sw.ElapsedMilliseconds);
            Console.ReadLine();
        }
    }
}

J#

<code>package ConsoleJSharp;
import System.*;
import System.Diagnostics.*;
public class Program
{
    public static void main(String[] args)
    {
        System.Text.StringBuilder sbSomeString = new System.Text.StringBuilder();
        Stopwatch sw = new Stopwatch();
        sw.Start();
        for (int i = 0; i < 1000; i++)
        {
            sbSomeString.Append("Test ");
        }
        sw.Stop();
        Console.WriteLine(sbSomeString.ToString());
        Console.WriteLine("Time Taken :" + sw.get_ElapsedMilliseconds());
        OldCode();
    }
    public static void OldCode()
    {
        String strSomeString = String.Empty;
        Stopwatch sw = new Stopwatch();
        sw.Start();
        for (int i = 0; i < 1000; i++)
        {
            strSomeString += "Test ";
        }
        sw.Stop();
        Console.WriteLine(strSomeString);
        Console.WriteLine("Time Taken :" + sw.get_ElapsedMilliseconds());
        Console.ReadLine();
    }
}

C++

<code>
#include "stdafx.h"
#using <mscorlib.dll>
using namespace System;
using namespace System::Diagnostics;
void OldCode();
int main(array<System::String ^> ^args)
{
    System::Text::StringBuilder^ sbSomeString = gcnew System::Text::StringBuilder();
    Stopwatch^ sw = gcnew Stopwatch;
    sw->Start();
    for (int i = 0;i< 1000 ;i++)
    {
        sbSomeString->Append("Test ");
    }
    sw->Stop();
    Console::WriteLine(sbSomeString->ToString());
    Console::WriteLine("Time Taken :" + sw->ElapsedMilliseconds);
    OldCode();
    return 0;
}
void OldCode()
{
    String^ strSomeString = String::Empty;
    Stopwatch^ sw = gcnew Stopwatch;
    sw->Start();
    for (int i = 0;i< 1000 ;i++)
    {
        strSomeString +=  "Test ";
    }
    sw->Stop();
    Console::WriteLine(strSomeString);
    Console::WriteLine("Time Taken :" + sw->ElapsedMilliseconds);
    Console::ReadLine();
}

The MSIL

VB

<code>
 .method public static void  Main() cil managed
{
  .entrypoint
  .custom instance
           void [mscorlib]System.STAThreadAttribute::.ctor() = ( 01 00 00 00 )
  // Code size       103 (0x67)
  .maxstack  2
  .locals init ([0] class [mscorlib]System.Text.StringBuilder sbSomeString,
           [1] class [System]System.Diagnostics.Stopwatch sw,
           [2] int32 i,
           [3] int32 VB$CG$t_i4$S0)
  IL_0000:  nop
  IL_0001:  newobj     instance void [mscorlib]System.Text.StringBuilder::.ctor()
  IL_0006:  stloc.0
  IL_0007:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_000c:  stloc.1
  IL_000d:  ldloc.1
  IL_000e:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_0013:  nop
  IL_0014:  ldc.i4.0
  IL_0015:  stloc.2
  IL_0016:  ldloc.0
  IL_0017:  ldstr      "Test "
  IL_001c:  callvirt   instance class [mscorlib]System.Text.StringBuilder
                       [mscorlib]System.Text.StringBuilder::Append(string)
  IL_0021:  pop
  IL_0022:  nop
  IL_0023:  ldloc.2
  IL_0024:  ldc.i4.1
  IL_0025:  add.ovf
  IL_0026:  stloc.2
  IL_0027:  ldloc.2
  IL_0028:  ldc.i4      0x3e8
  IL_002d:  stloc.3
  IL_002e:  ldloc.3
  IL_002f:  ble.s       IL_0016
  IL_0031:  ldloc.1
  IL_0032:  callvirt
                        instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_0037:  nop
  IL_0038:  ldloc.0
  IL_0039:  callvirt
                        instance string [mscorlib]System.Text.StringBuilder::ToString()
  IL_003e:  call        void [mscorlib]System.Console::WriteLine(string)
  IL_0043:  nop
  IL_0044:  ldstr       "Time Taken :"
  IL_0049:  ldloc.1
  IL_004a:  callvirt    instance int64
                        [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_004f:  call        string
                        [Microsoft.VisualBasic]
                        Microsoft.VisualBasic.CompilerServices.Conversions::ToString(int64)
  IL_0054:  call        string [mscorlib]System.String::Concat(string,
                                                              string)
  IL_0059:  call        void [mscorlib]System.Console::WriteLine(string)
  IL_005e:  nop
  IL_005f:  call        void VBConsole.Module1::OldCode()
  IL_0064:  nop
  IL_0065:  nop
  IL_0066:  ret
} // end of method Module1::Main

.method public static void  OldCode() cil managed
{
  // Code size          98 (0x62)
  .maxstack  2
  .locals init ([0]    string strSomeString,
           [1] class   [System]System.Diagnostics.Stopwatch sw,
           [2] int32 i,
           [3] int32 VB$CG$t_i4$S0)
  IL_0000:  nop
  IL_0001:  ldsfld     string [mscorlib]System.String::Empty
  IL_0006:  stloc.0
  IL_0007:  newobj     instance void
                       [System]System.Diagnostics.Stopwatch::.ctor()
  IL_000c:  stloc.1
  IL_000d:  ldloc.1
  IL_000e:  callvirt   instance void
                       [System]System.Diagnostics.Stopwatch::Start()
  IL_0013:  nop
  IL_0014:  ldc.i4.0
  IL_0015:  stloc.2
  IL_0016:  ldloc.0
  IL_0017:  ldstr      "Test "
  IL_001c:  call       string [mscorlib]System.String::Concat(string,
                                                              string)
  IL_0021:  stloc.0
  IL_0022:  nop
  IL_0023:  ldloc.2
  IL_0024:  ldc.i4.1
  IL_0025:  add.ovf
  IL_0026:  stloc.2
  IL_0027:  ldloc.2
  IL_0028:  ldc.i4     0x3e8
  IL_002d:  stloc.3
  IL_002e:  ldloc.3
  IL_002f:  ble.s      IL_0016
  IL_0031:  ldloc.1
  IL_0032:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_0037:  nop
  IL_0038:  ldloc.0
  IL_0039:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_003e:  nop
  IL_003f:  ldstr      "Time Taken :"
  IL_0044:  ldloc.1
  IL_0045:  callvirt   instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_004a:  call       string [Microsoft.VisualBasic]
                       Microsoft.VisualBasic.CompilerServices.Conversions::ToString(int64)
  IL_004f:  call       string [mscorlib]System.String::Concat(string,
                                                              string)
  IL_0054:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0059:  nop
  IL_005a:  call       string [mscorlib]System.Console::ReadLine()
  IL_005f:  pop
  IL_0060:  nop
  IL_0061:  ret
} // end of method Module1::OldCode

C#

<code>
.method private hidebysig static void  Main(string[] args) cil managed
{
  .entrypoint
  // Code size       107 (0x6b)
  .maxstack  2
  .locals init ([0] class [mscorlib]System.Text.StringBuilder sbSomeString,
           [1] class [System]System.Diagnostics.Stopwatch sw,
           [2] int32 i,
           [3] bool CS$4$0000)
  IL_0000:  nop
  IL_0001:  newobj     instance void [mscorlib]System.Text.StringBuilder::.ctor()
  IL_0006:  stloc.0
  IL_0007:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_000c:  stloc.1
  IL_000d:  ldloc.1
  IL_000e:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_0013:  nop
  IL_0014:  ldc.i4.0
  IL_0015:  stloc.2
  IL_0016:  br.s       IL_002a
  IL_0018:  nop
  IL_0019:  ldloc.0
  IL_001a:  ldstr      "Test "
  IL_001f:  callvirt   instance class
            [mscorlib]System.Text.StringBuilder
            [mscorlib]System.Text.StringBuilder::Append(string)
  IL_0024:  pop
  IL_0025:  nop
  IL_0026:  ldloc.2
  IL_0027:  ldc.i4.1
  IL_0028:  add
  IL_0029:  stloc.2
  IL_002a:  ldloc.2
  IL_002b:  ldc.i4     0x3e8
  IL_0030:  clt
  IL_0032:  stloc.3
  IL_0033:  ldloc.3
  IL_0034:  brtrue.s   IL_0018
  IL_0036:  ldloc.1
  IL_0037:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_003c:  nop
  IL_003d:  ldloc.0
  IL_003e:  callvirt   instance string [mscorlib]System.Object::ToString()
  IL_0043:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0048:  nop
  IL_0049:  ldstr      "Time Taken :"
  IL_004e:  ldloc.1
  IL_004f:  callvirt   instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_0054:  box        [mscorlib]System.Int64
  IL_0059:  call       string [mscorlib]System.String::Concat(object,
                                                              object)
  IL_005e:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0063:  nop
  IL_0064:  call       void ConsoleCSharp.Program::OldCode()
  IL_0069:  nop
  IL_006a:  ret
} // end of method Program::Main

.method private hidebysig static void  OldCode() cil managed
{
  // Code size       102 (0x66)
  .maxstack  2
  .locals init ([0] string strSomeString,
           [1] class [System]System.Diagnostics.Stopwatch sw,
           [2] int32 i,
           [3] bool CS$4$0000)
  IL_0000:  nop
  IL_0001:  ldsfld     string [mscorlib]System.String::Empty
  IL_0006:  stloc.0
  IL_0007:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_000c:  stloc.1
  IL_000d:  ldloc.1
  IL_000e:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_0013:  nop
  IL_0014:  ldc.i4.0
  IL_0015:  stloc.2
  IL_0016:  br.s       IL_002a
  IL_0018:  nop
  IL_0019:  ldloc.0
  IL_001a:  ldstr      "Test "
  IL_001f:  call       string [mscorlib]System.String::Concat(string,
                                                              string)
  IL_0024:  stloc.0
  IL_0025:  nop
  IL_0026:  ldloc.2
  IL_0027:  ldc.i4.1
  IL_0028:  add
  IL_0029:  stloc.2
  IL_002a:  ldloc.2
  IL_002b:  ldc.i4     0x3e8
  IL_0030:  clt
  IL_0032:  stloc.3
  IL_0033:  ldloc.3
  IL_0034:  brtrue.s   IL_0018
  IL_0036:  ldloc.1
  IL_0037:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_003c:  nop
  IL_003d:  ldloc.0
  IL_003e:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0043:  nop
  IL_0044:  ldstr      "Time Taken :"
  IL_0049:  ldloc.1
  IL_004a:  callvirt   instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_004f:  box        [mscorlib]System.Int64
  IL_0054:  call       string [mscorlib]System.String::Concat(object,
                                                              object)
  IL_0059:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_005e:  nop
  IL_005f:  call       string [mscorlib]System.Console::ReadLine()
  IL_0064:  pop
  IL_0065:  ret
} // end of method Program::OldCode

J#

<code>
.method public hidebysig static void  main(string[] args) cil managed
{
  .entrypoint
  // Code size       122 (0x7a)
  .maxstack  2
  .locals init ([0] class [mscorlib]System.Text.StringBuilder sbSomeString,
           [1] class [System]System.Diagnostics.Stopwatch sw,
           [2] int32 i)
  IL_0000:  ldtoken    [vjslib]com.ms.vjsharp.lang.ObjectImpl
  IL_0005:  call       void
                       [mscorlib] System.Runtime.CompilerServices.
    RuntimeHelpers::RunClassConstructor
                 (valuetype [mscorlib]System.RuntimeTypeHandle)
  IL_000a:  newobj     instance void [mscorlib]System.Text.StringBuilder::.ctor()
  IL_000f:  stloc.0
  IL_0010:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_0015:  stloc.1
  IL_0016:  ldloc.1
  IL_0017:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_001c:  ldc.i4.0
  IL_001d:  stloc.2
  IL_001e:  br.s       IL_0030
  IL_0020:  ldloc.0
  IL_0021:  ldstr      "Test "
  IL_0026:  callvirt   instance class [mscorlib]System.Text.StringBuilder
                       [mscorlib]System.Text.StringBuilder::Append(string)
  IL_002b:  pop
  IL_002c:  ldloc.2
  IL_002d:  ldc.i4.1
  IL_002e:  add
  IL_002f:  stloc.2
  IL_0030:  ldloc.2
  IL_0031:  ldc.i4     0x3e8
  IL_0036:  blt.s      IL_0020
  IL_0038:  ldloc.1
  IL_0039:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_003e:  ldloc.0
  IL_003f:  callvirt   instance string [mscorlib]System.Text.StringBuilder::ToString()
  IL_0044:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0049:  newobj     instance void [vjslib]java.lang.StringBuffer::.ctor()
  IL_004e:  ldstr      "Time Taken :"
  IL_0053:  callvirt   instance class
                       [vjslib]java.lang.StringBuffer
                       [vjslib]java.lang.StringBuffer::append(string)
  IL_0058:  ldloc.1
  IL_0059:  callvirt   instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_005e:  callvirt   instance class
                       [vjslib]java.lang.StringBuffer
                       [vjslib]java.lang.StringBuffer::append(int64)
  IL_0063:  callvirt   instance string [vjslib]java.lang.StringBuffer::ToString()
  IL_0068:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_006d:  call       void ConsoleJSharp.Program::OldCode()
  IL_0072:  call       void
                       [vjslib]com.ms.vjsharp.util.Utilities::cleanupAfterMainReturns()
  IL_0077:  br.s       IL_0079
  IL_0079:  ret
} // end of method Program::main

.method public hidebysig static void  OldCode() cil managed
{
  // Code size       118 (0x76)
  .maxstack  2
  .locals init ([0] string strSomeString,
           [1] class [System]System.Diagnostics.Stopwatch sw,
           [2] int32 i)
  IL_0000:  ldsfld     string [mscorlib]System.String::Empty
  IL_0005:  stloc.0
  IL_0006:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_000b:  stloc.1
  IL_000c:  ldloc.1
  IL_000d:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_0012:  ldc.i4.0
  IL_0013:  stloc.2
  IL_0014:  br.s       IL_0035
  IL_0016:  newobj     instance void [vjslib]java.lang.StringBuffer::.ctor()
  IL_001b:  ldloc.0
  IL_001c:  callvirt   instance class [vjslib] java.lang.StringBuffer
                       [vjslib]java.lang.StringBuffer::append(string)
  IL_0021:  ldstr      "Test "
  IL_0026:  callvirt   instance class [vjslib]java.lang.StringBuffer
                       [vjslib]java.lang.StringBuffer::append(string)
  IL_002b:  callvirt   instance string [vjslib]java.lang.StringBuffer::ToString()
  IL_0030:  stloc.0
  IL_0031:  ldloc.2
  IL_0032:  ldc.i4.1
  IL_0033:  add
  IL_0034:  stloc.2
  IL_0035:  ldloc.2
  IL_0036:  ldc.i4     0x3e8
  IL_003b:  blt.s      IL_0016
  IL_003d:  ldloc.1
  IL_003e:  callvirt   instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_0043:  ldloc.0
  IL_0044:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0049:  newobj     instance void [vjslib]java.lang.StringBuffer::.ctor()
  IL_004e:  ldstr      "Time Taken :"
  IL_0053:  callvirt   instance class [vjslib]java.lang.StringBuffer
                       [vjslib]java.lang.StringBuffer::append(string)
  IL_0058:  ldloc.1
  IL_0059:  callvirt   instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_005e:  callvirt   instance class
                       [vjslib]java.lang.StringBuffer
                       [vjslib]java.lang.StringBuffer::append(int64)
  IL_0063:  callvirt   instance string [vjslib]java.lang.StringBuffer::ToString()
  IL_0068:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_006d:  call       string [mscorlib]System.Console::ReadLine()
  IL_0072:  pop
  IL_0073:  br.s       IL_0075
  IL_0075:  ret
} // end of method Program::OldCode

C++

<code>
.method assembly static int32  main(string[] args) cil managed
{
  // Code size       106 (0x6a)
  .maxstack  2
  .locals ([0] class [System]System.Diagnostics.Stopwatch sw,
           [1] int32 i,
           [2] class [mscorlib]System.Text.StringBuilder sbSomeString,
           [3] int32 V_3)
  IL_0000:  ldc.i4.0
  IL_0001:  stloc.3
  IL_0002:  ldnull
  IL_0003:  stloc.2
  IL_0004:  ldnull
  IL_0005:  stloc.0
  IL_0006:  newobj     instance void [mscorlib]System.Text.StringBuilder::.ctor()
  IL_000b:  stloc.2
  IL_000c:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_0011:  stloc.0
  IL_0012:  ldloc.0
  IL_0013:  call       instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_0018:  ldc.i4.0
  IL_0019:  stloc.1
  IL_001a:  br.s       IL_0020
  IL_001c:  ldloc.1
  IL_001d:  ldc.i4.1
  IL_001e:  add
  IL_001f:  stloc.1
  IL_0020:  ldloc.1
  IL_0021:  ldc.i4     0x3e8
  IL_0026:  bge.s      IL_0036
  IL_0028:  ldloc.2
  IL_0029:  ldstr      "Test "
  IL_002e:  call       instance class
                       [mscorlib]System.Text.StringBuilder
                       [mscorlib]System.Text.StringBuilder::Append(string)
  IL_0033:  pop
  IL_0034:  br.s       IL_001c
  IL_0036:  ldloc.0
  IL_0037:  call       instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_003c:  ldloc.2
  IL_003d:  callvirt   instance string [mscorlib]System.Text.StringBuilder::ToString()
  IL_0042:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0047:  ldstr      "Time Taken :"
  IL_004c:  ldloc.0
  IL_004d:  call       instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_0052:  box        [mscorlib]System.Int64
  IL_0057:  call       string [mscorlib]System.String::Concat(object,
                                                              object)
  IL_005c:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0061:  call       void modopt( [mscorlib]System.Runtime.CompilerServices.CallConvCdecl)
                       OldCode()
  IL_0066:  ldc.i4.0
  IL_0067:  stloc.3
  IL_0068:  ldloc.3
  IL_0069:  ret
} // end of method 'Global Functions'::main

.method assembly static void modopt ([mscorlib]System.Runtime.CompilerServices.CallConvCdecl)
        OldCode() cil managed
{
  .vtentry 1 : 1
  // Code size       97 (0x61)
  .maxstack  2
  .locals ([0] class [System]System.Diagnostics.Stopwatch sw,
           [1] string strSomeString,
           [2] int32 i)
  IL_0000:  ldnull
  IL_0001:  stloc.1
  IL_0002:  ldnull
  IL_0003:  stloc.0
  IL_0004:  ldsfld     string [mscorlib]System.String::Empty
  IL_0009:  stloc.1
  IL_000a:  newobj     instance void [System]System.Diagnostics.Stopwatch::.ctor()
  IL_000f:  stloc.0
  IL_0010:  ldloc.0
  IL_0011:  call       instance void [System]System.Diagnostics.Stopwatch::Start()
  IL_0016:  ldc.i4.0
  IL_0017:  stloc.2
  IL_0018:  br.s       IL_001e
  IL_001a:  ldloc.2
  IL_001b:  ldc.i4.1
  IL_001c:  add
  IL_001d:  stloc.2
  IL_001e:  ldloc.2
  IL_001f:  ldc.i4     0x3e8
  IL_0024:  bge.s      IL_0034
  IL_0026:  ldloc.1
  IL_0027:  ldstr      "Test "
  IL_002c:  call       string [mscorlib]System.String::Concat(string,
                                                              string)
  IL_0031:  stloc.1
  IL_0032:  br.s       IL_001a
  IL_0034:  ldloc.0
  IL_0035:  call       instance void [System]System.Diagnostics.Stopwatch::Stop()
  IL_003a:  ldloc.1
  IL_003b:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_0040:  ldstr      "Time Taken :"
  IL_0045:  ldloc.0
  IL_0046:  call       instance int64
                       [System]System.Diagnostics.Stopwatch::get_ElapsedMilliseconds()
  IL_004b:  box        [mscorlib]System.Int64
  IL_0050:  call       string [mscorlib]System.String::Concat(object,
                                                              object)
  IL_0055:  call       void [mscorlib]System.Console::WriteLine(string)
  IL_005a:  call       string [mscorlib]System.Console::ReadLine()
  IL_005f:  pop
  IL_0060:  ret
} // end of method 'Global Functions'::OldCode

Conclusion

I have not included all the assembly code that the compiler generates. I have only included what I think is worth noting, i.e. I have only included the code of the functions.

It is interesting to note that the StringBuilder class is able to perform the string concatenation in 0ms whereas the string concatenation takes much longer in the legacy method, on average 17ms

History

  • 06-10-06: Draft Version 1 Part 2 Uploaded
  • 09-10-06: Updated content, formatting and changed article title

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Three Nine Consulting
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A freelance software developer in the UK with over 12+ years software development experience. My fascination and passion for software development, technology and business has set me on a lifetime course of continual learning and self improvement. I value feedback, regardless whether it is negative or positive, it is one of the primary sources of inspiration to improve!
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GeneralNDepend PinmemberPatrick Smacchia MVP.NET6-May-07 13:54 

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