XCC

C compiler running on Linux or MacOS.

• Supporting architecture: x86-64, aarch64 (arm64), riscv64, wasm
• Binary format: ELF64

Requirements

• Linux (or MacOS)
• C compiler (gcc or clang)
• make

Build

$ make

Generated files:

• xcc: Compiler entry
• cpp: Preprocessor
• cc1: C compiler
• as: Assembler
• ld: Linker

Usage

$ ./xcc -o hello examples/hello.c
$ ./hello
Hello, world!

Command line options

• -o <filename>: Set output filename (default: a.out)
• -I <path>: Add include path
• -D <label>(=value): Define macro
• -S: Output assembly code
• -E: Preprocess only
• -c: Output object file
• -nodefaultlibs: Ignore libc
• -nostdlib: Ignore libc and crt0

TODO

• Optimization
• Archiver

Reference

• 低レイヤを知りたい人のためのCコンパイラ作成入門
• rui314/9cc: A Small C Compiler

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WebAssembly

Compile C to WebAssembly/WASI binary.

Online demo

Requirements

• node.js, npm
• llvm-ar

Set up

$ npm ci

Build

$ make wcc

Generated files:

• wcc: C compiler (including preprocessor, and output .wasm directly)

Usage

Compile:

$ ./wcc -o hello.wasm examples/hello.c

Command line options:

• -o <filename>: Set output filename (default: a.wasm)
• -I <path>: Add include path
• -D <label>(=value): Define macro
• -E: Preprocess only
• -c: Output object file
• --entry-point=func_name: Specify entry point (default: _start)
• -e func_name,...: Export function names (comma separated)
• --stack-size=<size>: Set stack size (default: 8192)
• -nodefaultlibs: Ignore libc
• -nostdlib: Ignore libc and crt0
• --verbose: Output debug information
• -Wl,...: Linker option
  • --allow-undefined: Handles unresolved function symbols as imported on runtime
  • --export-all: Export all non-static functions

Run

$ ./tool/runwasi hello.wasm
Hello, world!

You can also use WASM/WASI runtime (Wasmtime, Wasmer, etc.), too.

Limitation

• goto: Can jump ancestor and latter line only.