vanilla is a small C compiler that implements most C11 features. even though it still probably falls into the "babby's first compiler" category just like other small compilers do, vanilla can compile things such as git, sqlite, libpng and itself without making modifications to the programs themselves. generated executables of these programs pass their corresponding test suites. so, vanilla actually supports a wide range of C11 features and is able to compile hundreds of thousands of lines of "real-world" C code correctly.
vanilla supports almost all mandatory features and most optimal features of C11 and some GCC language extensions.
features that are often missing in a small compiler but supported by vanilla include but not limited to:
- preprocessor
- float, double and long double / x87 80-bit floating point numbers
- bit-fields
- alloca()
- variable-length arrays
- compound literals
- thread-local variables
- atomic variables
- common symbols
- designated initializers
- L, u, U, and u8 string literals
- functions that take or return structs as values, as specified by the x86-64 SystemV ABI
vanilla does not support complex numbers, K&R-style function prototypes and GCC-style inline assembly. digraphs and trigraphs are intentionally left out.
vanilla outputs a simple error message when it finds an error in the source code.
there's no optimization pass. vanilla can and will spit out terrible code which is probably 2x slower than GCC's output. i'll add one eventually.
vanilla consists of the following stages:
-
tokenize: takes a string as an input, breaks it into a list of tokens and returns them.
-
preprocess: takes a list of tokens as input and outputs a new list of macro-expanded tokens. it interprets preprocessor directives while expanding macros.
-
parse: recursive descendent parser which constructs abstruct syntax trees from the output of the preprocessor. it also adds a type of each AST nodes.
-
codegen: emits an assembly text for given AST nodes. i hated writing this the most.
anyway enjoy