Microsoft Intermediate language

1
Microsoft Intermediate language

• CLI vs. JVM

2
Why intermediate language?

• Portability
• Compactness
• Efficiency
• Security
• Interoperability

3
CLI (Common Language Infrastructure)Architecture

• A linked list of stack frames
• IP (Instruction Pointer)
• Evaluation stack
• A (zero-based) array of local variable
• A (zero-based) array of incoming arguments
• Method info handle
• A local memory pool
• A return state handle
• A security descriptor

4
A simple example
//hello.cil .assembly hello .ver
1000 .method public static void main() il
managed .entrypoint .maxstack
1 ldstr "Hello World with IL\n
call void mscorlibSystem.ConsoleWriteLine(
class System.String) ret
Ilasm hello.cil
5
MSIL Instruction Set

• Argument, local variables, Constant, pointers
• ldc.t v, ldarg n, ldloc n, ldloca n,stloc n
  ldind.t
• Arithmetic
  add, sub
• Control flow
  br, beq, bge

6
MSIL Instruction Set( value types)

• Structures
• .class value Point
• .field public int x
• .field public int y
• Unions
• .class value explicit FloatOrInt
• .field 0 public float32 f
• .field 0 public int32 n
• Enum
• .class enum Shape
• .field public static valuetype Shape RECTANGLE
  int32(0)
• .field public static valuetype Shape CIRCLE
  int32(1)

7
MSIL Instruction Set( reference types)

• Classes
• Interfaces
• Arrays
• Delegates

8
.NET vm vs. JVM

• Purpose
• Object oriented model
• Stack slots
• Type of instructions
• Code density
• Number of instructions