c-compiler

• A compiler for our simple C language

Author

• Pan Zhiyuan @pan2013e
• Meng Junyi @MJYINMC
• Su Zhe @bugsz

Feature

Stable

• Simple variable / constant definition and use, both locally and globally
• Multiple simple type: int, short, long, double, string, char
• One-level pointer to a simple variable, and corresponding ref and deref operation
• One-dimensional array, support using array name as a pointer
• Function definition, declaration and call
• Basic control flow (for, if, while, do-while)
• Supported binary operators: +, -, *, /, >, <, >=, <=, =, &&, ||, <<, >>, &, |, ^, and all ops like +=, -=, ...
• Supported unary operators: +, -, *, &, (), ~, !
• Can distinguish i++ and ++i
• Support type conversion, both explicitly (by using unary operator () ) and implicitly (by assignment or operation)
• Support scope
• Support built_in function provided by libc (printf, puts, malloc, scanf, sqrt...)
• Support for va_args
• Support macro definition and function
• Support header file

Experimental

• Two-dimensional array (On more_flexible_syntax branch)

Compile

Prerequisites

Frontend

• GNU Autotools(automake, autoconf)
• flex & bison
  • Note: The program passed tests with flex version >= 2.6.4 & bison version >= 3.7.5. Lower version of bison may result in compilation failure.
  • For macOS, you need to install the latest version of bison through Homebrew or other sources. Then, you need to modify the generated Makefile by replacing bison（in Makefile, just search for YACC = bison -y） with the newer vesion's path, for example, /opt/homebrew/opt/bison/bin/bison.

Backend

• GNU CMake >= 3.13.4 (lower is ok but you have to change cmakelist.txt)
• Clang/Clang++ compiler with >=c99 & >=c++17 support
• llvm-13

Build

• Execute the following command under the root of the project, then you should see ./c-compiler in the folder. If your system cc and c++ is not clang/clang++, may cause issue, so set CC=clang CXX=clang++ to avoid trouble.

  mkdir build && cd build
  CC=clang CXX=clang++ cmake .. -DALL=ON
  make

• cmake command above finishes the task of compiling both frontend and backend separately into static library(with ALL option ON). And make takes these two libraries and put them together into an executable.

  • Options ALL: When it is ON, cmake will build the frontend library, otherwise only backend library will be build. Our suggestion is to use cmake .. when you already had the static frontend library.

  • Options LIBC_DIR: Specify libc path if you have multiple versions of libc on your system, otherwise, we will use the system libc which is discovered by cmake find_library().

Usage

❯ ./c-compiler --help
Usage: C-Compiler [options]

Optional arguments:
-h --help                               shows help message and exits [default: false]
-v --version                            prints version information and exits [default: false]
-o --output                             specify output file name [default: "a.out"]
-f --file                               specify source file name [default: ""]
-c                                      compile to object code only [default: false]
-E                                      preprocess only [default: false]
-w -fno-warnings --fno-warnings         disable warnings [default: false]
-D -I -U -i                             preprocessor flags, space must be used to separate flag and parameter
-stdin --stdin                          use input from stdin [default: false]
-ast-dump --ast-dump                    print AST [default: false]
-sym-dump --sym-dump                    print symbol table [default: false]
-static-analyze --static-analyze        run static program analysis only [default: false]
-fno-preprocess --fno-preprocess        disable preprocessing [default: false]

Credits

p-ranav/argparse danmar/simplecpp