github.com/PhilippRados/wrecc @v0.2.0

<img src="https://i.ibb.co/1bfxpbb/wreckage-mj.jpg" width="800">

wrecc is a small,lean x86-64 C99 compiler written from scratch. The name is a play on the word wreck which describes a rusting ship on the sea floor. The compiler emits x86-64 assembly in AT&T syntax, it adheres to the System V ABI which I could only test for Ubuntu and Macos. There are no dependencies you only need your assembler and linker which the compiler then invokes to create the final binary.

Table of contents

• Installation
• Pre-built binaries
• Cargo
• Features
• Preprocessor
• Compiler
  • Supported keywords
  • Unimplemented features
• Error messages
• Ast pretty-printer
• Testing
• Unit-tests
• Snapshot-tests
• Fuzzer
• Troubleshooting
• Contribution
• Project goals
• Resources

Installation

Pre-built binaries

If you don't have the rust toolchain installed on your system you can install the latest binary (MacOs, Linux) from the releases directly:

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/PhilippRados/wrecc/releases/download/v0.2.0/wrecc-installer.sh | sh

Cargo

Using cargo binstall

cargo binstall wrecc

or building from source

cargo install wrecc

Features

Since not all keywords are currently implemented wrecc uses custom standard-headers which are built directly into the binary

Preprocessor

The preprocessor implements all C99 preprocessor directives, except #line, #error and #pragma. Most prominently it currently also misses function-like macros which are on the agenda though.

Compiler

Supported Keywords

Other than that it even supports:

Aggregate initialization with designated initializers

C struct { union { int foo; long baz; } nested; int array[16]; } bar = { .nested.foo = 3, .array[6] = 1};

Function pointers

```C #include

typedef int (*BinaryOperation)(int, int); typedef struct { BinaryOperation add; BinaryOperation subtract; } Calculator;

int add(int a, int b) { return a + b; } int subtract(int a, int b) { return a - b; }

int main() { Calculator calc = {add, subtract};

printf("Result of addition: %d\n", calc.add(10, 5));
printf("Result of subtraction: %d\n", calc.subtract(10, 5));

}

```

Constant folding

C char **string_offset = (char **)&"hello" + (int)(3 * 1); int array[(long)3 * 2 - 1];

Unimplemented Features

Aside from the missing keywords these are the main missing features: - [x] Arrays with unspecified size - [x] Compiling multiple files at once - [ ] Raw structs/unions as function argument-/return-types - [ ] Floating point types

Here is a list of all the stuff still missing: todo

Error messages

Wrecc also has nice looking messages. Error reporting doesn't stop after the first error. Using the --no-color option you can switch off color-highlighting in errors. Currently there are only errors and no warnings.

C code	Errors
```C int foo(void); int main() { int a = foo(1); long *p = a; return p * 2; } ```

Ast pretty-printer

When compiling using the --dump-ast option it prints the parse-tree

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#### Inspect all options by running `wrecc --help`

## Testing
#### Unit tests <a name="unit"></a>

#### Snapshot testing <a name="snap"></a>
This runs all [fixtures](https://github.com/PhilippRados/wrecc/tree/master/tests/fixtures) and compares them to the expected [snapshot](https://github.com/PhilippRados/wrecc/tree/master/tests/snapshots)

#### Fuzzer
Runs the fuzzer using [afl.rs](https://github.com/rust-fuzz/afl.rs)