dumbc — small C Compiler

A small C compiler written for learning.

Built by following Nora Sandler’s "Write a Compiler" series.

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Supported Architectures

• arm64 (darwin and linux only)

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Implemented Parts

• Part 1: Compile int main() { return <int>; }
• Part 2: Add unary operators (-, ~, !)
• Part 3: Add binary operators (+, -, etc.)
• Part 4: Even More Binary Operators (&&, ||, ==, !=, <, <=, >, >=)
• Part 4.1: Other Binary Operators (%, &, |, ^, <<, >>)
• Part 5: Local Variables
• Part 5.1:
  • Compound Assignment Operators (+=,-=,/=,*=,%=,<<=,>>=,&=,|=,^=)
  • Increment/Decrement(++/--)
  • Comma operators (int a = 2, b, c = a + 4;)
• Part 6: Conditionals
• Part 7: Compound Statements
• Part 8: Loops
• Part 9: Functions (with calls to the C standard library!)
• Part 10: Global Variables
• Part II of Writing a C Compiler book
  • floating-point numbers
  • arrays and pointers
  • structs
• Constants
• Optimizations
  • constant folding
  • dead code elimination

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Usage

Compile and run a .c file:

cargo run -- path/to/file.c [--arch arm64] [--platform macos|linux]

• If --arch is not specified, the system architecture is used. Same for --platform
• Only arm64 is supported now

Example:

cargo run -- examples/return_42.c

Produces return_42.s

You can compile it with aarch64 GCC or run with QEMU.

Example for macOS:

clang -arch arm64 -o return_42_mac return_42.s
./return_42
echo $?  # prints: 42

Non-standard features

bingus keyword

bingus(arg) is a built-in pseudo-function, which evaluates expression and prints it into stdout. Available on macOS platform

DEPRECATED: calls to the standard library functions are supported

Example:

int main() {
    int a = 10, b = 8;
    bingus(a);
    bingus(a * b);
    bingus(b - 10);
}

Output:

10
80
-2

Tests

The testsuite submodule contains tests cases from nlsandler/write_a_c_compiler.

To run them, use

python run_tests.py

License

This compiler is licensed under the GNU General Public License, as described in the LICENSE file.