MiniCCompiler

Ahmed Elmi

This project implements a MiniC compiler in four stages:

1. frontend/: lexing, parsing, AST construction, and semantic analysis
2. ir_builder/: AST to LLVM IR
3. optimizations/: LLVM IR optimization passes
4. backend/: LLVM IR to x86 32-bit assembly

Requirements

• g++
• flex
• bison
• LLVM development tools for ir_builder, optimizations, and backend
• clang
• Linux with clang -m32 for the full backend runtime tests

The LLVM-based Makefiles try these automatically:

1. /opt/homebrew/opt/llvm/bin/llvm-config
2. llvm-config
3. llvm-config-18
4. llvm-config-17

Build

From the project root:

make

This builds:

• frontend/parser
• ir_builder/ir_builder
• optimizations/optimizer
• backend/backend

Stage Tests

From the project root:

make tests

or:

make test-all

to run the full suite, or run the stage tests individually:

make test-parser
make test-semantic
make test-builder
make test-optimizations
make test-backend

Notes:

• test-backend runs full runtime comparisons only on Linux with clang -m32
• On unsupported systems such as macOS, test-backend prints a skip message instead of failing

Manual Pipeline

Frontend

./frontend/parser path/to/program.c

IR builder

./ir_builder/ir_builder ./tests/builder_tests/p1.c /tmp/p1.ll

Optimizer

./optimizations/optimizer /tmp/p1.ll /tmp/p1_opt.ll

Local-only optimization mode:

./optimizations/optimizer --local ./tests/optimizations/cfold_add.ll /tmp/cfold_add_opt.ll

Backend

./backend/backend /tmp/p1_opt.ll /tmp/p1.s

The backend input is LLVM IR (.ll). The output is AT&T-style x86 32-bit assembly (.s).

Full Example

./ir_builder/ir_builder ./tests/assembly_gen_tests/square.c /tmp/square.ll
./optimizations/optimizer /tmp/square.ll /tmp/square_opt.ll
./backend/backend /tmp/square_opt.ll /tmp/square.s

On Linux, you can assemble and run it with:

clang -m32 /tmp/square.s ./tests/assembly_gen_tests/main.c
./a.out

Project Layout

• frontend/: lexer, parser, AST library, semantic analysis
• ir_builder/: LLVM IR generation from the MiniC AST
• optimizations/: local and global LLVM IR optimization passes
• backend/: handwritten x86 code generation with local register allocation
• tests/: parser, semantic, builder, optimization, and assembly-generation tests

Folder README Files

Each stage folder has its own README with:

• what that stage does
• how to build it directly
• how to run it manually
• how to test it with make