What Programming Languages are Used for Writing Compilers?

Compilers, which convert source code written in a programming language into machine code or another intermediate language, can be developed using a variety of programming languages. The choice of programming language often depends on performance requirements, project goals, and specific features of the language being compiled. In this article, we explore the common programming languages used for creating compilers, including reasons for their selection and examples of well-known compilers written in different languages.

Common Programming Languages for Compilers

Several programming languages have been employed in the development of compilers, each with its unique advantages:

C/C

Many high-performance compilers, such as GCC (GNU Compiler Collection) and Clang, are written in C or C . These languages offer low-level access to memory and system resources, which is crucial for optimizing performance. High-performance and low-level control make C and C particularly suitable for creating highly optimized compilers.

Java

Some compilers, like the Java Compiler (javac), are developed using Java itself. This approach simplifies development and ensures portability across various platforms. Java's platform independence and extensive standard library make it an attractive choice for writing compilers.

Python

Python is widely used for educational purposes, especially in teaching compiler design. Due to its ease of use and readability, Python is often chosen for developing simple compilers or interpreters. Its simplicity and flexibility make it ideal for demonstrating fundamental compiler concepts without the complexity of low-level language features.

Rust

Rust's increasing popularity in compiler development is primarily due to its strong memory safety features and performance. The Rust Compiler (rustc) is a notable example of a compiler written in Rust. Rust's robustness and compile-time safety make it a compelling choice for developing compilers that require high-performance and memory safety.

ML and Haskell

Functional programming languages such as ML and Haskell are often used for compilers, especially those that involve complex type systems or require advanced language features. The GHC (Glasgow Haskell Compiler) is a well-known example of a compiler written in Haskell, highlighting the suitability of functional languages for intricate compiler design.

Assembly Language

Some low-level compilers or parts of compilers might be written in assembly language for maximum control over hardware. Assembly language offers the most precise control over instructions, making it suitable for specific optimizations at the hardware level.

Real-World Examples: Compilers in PL/1, C, and Assembly

My experience with Stratus machines running the VOS operating system highlights the diversity of programming languages used in compiler development. The PL/1 compiler on Stratus machines was written in PL/1 itself, while the Fortran compiler was also in PL/1. Unix/Linux compilers are typically written in C, depending on the hardware or operating system manufacturer.

When developing a new compiler, the choice of programming language depends on several factors, including:

Project goals and requirements Performance needs Ease of implementation and maintainability Pre-existing expertise of the development team

For an entirely new language, the initial version is often written in another language for which a compiler is already available. This ensures a working prototype and allows the team to familiarize themselves with the new language. Compiler construction tools and libraries, such as lexer and parser generators, can also be used to speed up the process. Once the compiler's basic functionality is established, it is often rewritten in the target language for optimization and long-term maintenance.

In the case of a new compiler for an existing language, the development is typically done in that language. Using an existing compiler to compile the initial version provides a robust and stable foundation for further development. This approach ensures that the new compiler successfully compiles and runs the source code of the target language.

Ultimately, the choice of programming language for a compiler is strategic and based on the specific needs of the project. From the performance-critical C and C , to the versatile Java, Python, and Rust, and the precise control of assembly language, each language offers unique benefits and advantages in compiler development.