1. Run-Time Storage Organization

2. Introduction
We need to relate the static source text of a program to the actions that must occur at run time
We need to allocate and manage the memory used by the program (static and dynamic)

3. Memory Allocation Techniques
Static Allocation
Stack Allocation
Heap Allocation
Code
Static Data
Stack
Heap

4. Static Allocation
The number and size of all objects to be allocated is known at compile time
It is used for:
Global variables that are fixed in size and accessible throughout program execution
Program literals (constants)
Program code

5. Stack Allocation
Information needed by a single execution of a routine (a procedure, function or method) is managed using an activation record or frame
An activation record contains local variables, parameters, return address, etc.
Activation records are pushed and popped as functions calls begin and end

6. Parameter Passing Call-by-value can be implemented as follows:
A formal parameter is treated like a local variable, so the storage for the formal is in the activation record of the called routine
The caller evaluates the actual parameters and places their values in the storage for the formals
Call-by-reference
The caller passes to the called procedure a reference to the storage address of each actual parameter

7. Heap Allocation
The heap is used to store data which can be allocated and freed at any time and in any order
Deallocation is either manual or automatic (garbage collection)
The heap typically becomes fragmented during use