What is the Difference Between Phase and Pass in Compiler?

The difference between phase and pass in a compiler lies in their roles within the compilation process:

• Phase: A phase is a distinguishable stage in the compiler that takes input from the previous stage, processes it, and yields output that can be used as input for the next stage. Phases are the steps in the compilation process, and each phase takes input from the previous stage. Examples of phases include lexical analysis, syntax analysis, and code generation.
• Pass: A pass refers to the traversal of a compiler through the entire program. It is the total number of times the compiler goes through the entire program during the compilation process. Each pass takes the result of the previous pass as input and creates intermediate outputs, allowing the code to improve in each pass. The final code is generated after the final pass.

A pass can have more than one phase. The main difference between phases and passes is that phases are the steps in the compilation process, while passes are the total number of times the compiler goes through the entire program.

Comparative Table: Phase vs Pass in Compiler

The difference between phases and passes in a compiler is that phases are distinct stages in the compilation process, whereas passes refer to the total number of times the compiler goes through the entire program. Here is a table summarizing the differences between phases and passes in a compiler:

In summary, phases are the individual steps in the compilation process, while passes refer to the compiler going through the entire program multiple times to iterate and optimize the code.