Bootstrapping

A compiler is characterized by three languages:

1. Source Language
2. Target Language
3. Implementation Language

Notation: represents a compiler for Source S, Target T, implemented in I. The T-diagram shown above is also used to depict the same compiler.

To create a new language, L, for machine A:

1. Create , a compiler for a subset, S, of the desired language, L, using language A, which runs on machine A. (Language A may be assembly language.)

   

2. Create , a compiler for language L written in a subset of L.
3. Compile using to obtain , a compiler for language L, which runs on machine A and produces code for machine A.

The process illustrated by the T-diagrams is called bootstrapping and can be summarized by the equation:

To produce a compiler for a different machine B:

1. Convert into (by hand, if necessary). Recall that language S is a subset of language L.
2. Compile to produce , a cross-compiler for L which runs on machine A and produces code for machine B.
3. Compile with the cross-compiler to produce , a compiler for language L which runs on machine B.