During the execution of a program, the same name in the source can denote different data objects in the computer.
The allocation and deallocation of data objects is managed by the run-time support package.
Terminologies
- Name storage space: The mapping of a name to a storage space is Called environment
- Storage space value: The current value of a storage space is called its state.The association of a name to a storage location is called a binding. Each execution of a procedure is called an activation. If it is a recursive procedure, then several of its activations may exist at the same time.
- Life time: The time between the rst and last steps in a procedure. A recursive procedure needs not to call itself directly.
General run time storage layout
Activation record
| Temporaries | Stores temporary and intermediate values of an expression. |
| Local Data | Stores local data of the called procedure. |
| Machine Status | Stores machine status such as Registers, Program Counter etc., before the procedure is called. |
| Control Link | Stores the address of activation record of the caller procedure. |
| Access Link | Stores the information of data which is outside the local scope. |
| Actual Parameters | Stores actual parameters, i.e., parameters which are used to send input to the called procedure. |
| Return Value | Stores return values. |