Very tiny compiler for a simple arithmetic language.
This is a tiny compiler which produces assembler code targeting a particular very simple stack machine out of an even simpler arithmetic language. Put together for an experiment in compiler verification.
Builds a treat under Windows using the Tiny C Compiler by the one and only Fabrice Bellard.
tcc tiny.c
The source language consists of an arbitrarily deep tree of expressions. An expression may take the form of a number or three-member tuple containing an operator followed by exactly two operands which must each themselves be expressions. In EBNF:
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9".
number = digit { digit }.
operator = "add" | "sub" | "mul" | "div".
expression = number | ( "(" operator expression expression ")" ).
This grammar is written to be compatible with a piece of visualization software developed by a team at the University of Linz. To save you downloading it and rendering the grammar, here it is visually:
The target for this compiler is the Simple Stack Machine. The source code:
(add 1 2)
Will produce the following result:
ldc 1
ldc 2
add
This will push two constants onto the stack (using the ldc command) and then add them together, pushing the result back on to the stack.
This 'compiler' obviously has a few limitations:
- The language obviously isn't a serious development language.
- Memory currently isn't deallocated before program exit so your OS better do it for you. This may be addressed in future.