1.2 What is the Challenge?

Many variations:

• many programming languages (eg, Java, C++, Scala)
• many programming paradigms (eg, object-oriented, functional, logic)
• many computer architectures (eg, x86, MIPS, ARM, alpha, PowerPC)
• many operating systems (eg, Linux, OS X, Microsoft Windows, Android, iOS)

Qualities of a compiler (in order of importance):

1. the compiler itself must be bug-free
2. it must generate correct machine code
3. the generated machine code must run fast
4. the compiler itself must run fast (compilation time must be proportional to program size)
5. the compiler must be portable (ie, modular, supporting separate compilation)
6. it must print good diagnostics and error messages
7. the generated code must work well with existing debuggers
8. must have consistent and predictable optimization.

Building a compiler requires knowledge of

• programming languages (parameter passing, variable scoping, memory allocation, etc)
• theory (automata, context-free languages, etc)
• algorithms and data structures (hash tables, graph algorithms, dynamic programming, etc)
• computer architecture (assembly programming)
• software engineering.

The course project (building a non-trivial compiler for a Pascal-like language) will give you a hands-on experience on system implementation that combines all this knowledge.