BeC-- is a small compiler for the C programming language(subset), compile to assembly code and run on Raspbery4B/ARMv7 32bits. It's intended to support most C11 language features while keeping the code as small and simple as possible.

flex 2.6.0
bison 3.0.4
clang 3.8.0

• positive integers (no other types yet)
• local variables
• array support
• integer or array constants
• variable assignment
• arithmetic expressions (foo + bar foo - bar foo * bar foo / bar)
• rel expressions (foo == bar, foo != bar, foo < bar, foo <= bar, foo > bar, foo >= bar)
• logical expression (foo && bar, foo || bar)
• unary op expresions (+FOO, -FOO, !FOO)
• Comments (// foo and /* foo */)
• sequences of statements (foo; bar)
• if statements (if (foo) { bar } and else if (foo) {bar} else {bar})
• while loops (while (foo) { bar })
• return statement
• break statement
• continue statement
• function definitions and calls
• multilevel block

use flex for lexical analysis and bison to build AST(abstract syntax tree).

BeC-- generates code from AST directly. The algorithm is 1-TOSCA (top of stack caching). It is far from generating efficient code, but at least it works and generates code efficently.

cd src
make

cd src

// test all
sh testall.sh ../testcase/functional_test

// test one
./compiler -S -o testcase.s ../testcase/functional_test/00_main.sy

make clean

a simple toturial for lex&yacc https://www.epaperpress.com/lexandyacc/index.html

Flex doc http://dinosaur.compilertools.net/flex/index.html

Bison doc https://www.gnu.org/software/bison/manual/html_node/index.html