Do comments slow down a compiled language?

Question

This question has been asked several times here about interpreted language or R but I don't find anything about a compiled language, specifically C#.

According to what I read it seems to be negligible but it still induces a very little slowdown on interpreted language: Do comments slow down an interpreted language?

What about compiled languages?! do they slow down only the compilation process but not execution?

Answer 1

When you compile the program, the compiler actually does:

• Lexical Analysis (tokenization)
• Syntax Analysis (parsing)
• Semantic Analysis (language rules checked)
• [Intermediate] Code Generation
• Code Optimization (optional)

As for comments they should be extracted as tokens on Lexical Analysis stage and dropped out on Syntax Analysis (parsing) stage. So you can slow down the compiler, but not the code generated.

Many interpreted languages often do first two or three stages and only then execute, so comments don't necessarily slow down even interpreted languages.

Answer 2

Compilers have these phases:

• Lexical analysis
• Syntax analysis
• Semantic analysis
• Generating machine independent code
• Code optimization
• Generating final code

In Lexical analysis, comments are skipped, it is basically like you didn't write anything.

So no, they do not affect performance in any way.