saltwater: the part of the sea causing lots of rust
A C compiler written in Rust, with a focus on good error messages.
swcc
reads from standard in by default, so you can type in code directly.
It's not interactive though, you have to hit Ctrl+D to indicate end of file (Ctrl+Z on Windows).
Use swcc --help
for all options (or see below).
You need to have cc
on your PATH. You can either install mingw + gcc or MSVC.
Other than that, it should work exactly the same as on Linux.
- Defining functions taking variadic arguments. Note that calling variadic functions (like
printf
) is already supported. - Variable-length arrays (
int a[n]
) - Multiple translation units (files)
- Bitfields
- Compiling on non-x86 platforms
- Cross-compilation
$ cat tests/runner-tests/readme.c
// output: j is 6
int printf(const char *, ...);
typedef struct s *sp;
int i = 1;
int a[3] = {1, 2, 3};
float f = 2.5;
struct s {
int outer;
} my_struct;
int g(int);
int main(void) {
sp my_struct_pointer = &my_struct;
const int c = my_struct_pointer->outer = 4;
// should return 6
int j = i + f*a[2] - c/g(1);
printf("j is %d\n", j);
return j;
}
int g(int i) {
if (i < 0 || i >= 3) {
return 0;
}
return a[i];
}
$ swcc tests/runner-tests/readme.c
$️ ./a.out
j is 6
$ cat tests/runner-tests/cpp/if/defined.c
// code: 2
#define a
#define b
#if defined(a)
int i = 2;
#endif
#ifndef b
syntax error
#endif
# if defined b && defined(a)
int main() { return i; }
#endif
$ swcc -E tests/runner-tests/cpp/if/defined.c
int i = 2 ; int main ( ) { return i ; }
$ echo 'int i = 1 + 2 ^ 3 % 5 / 2 & 1; int main(){}' | swcc --debug-ast
ast: int i = ((1) + (2)) ^ ((((3) % (5)) / (2)) & (1));
ast: int main(){
}
$ cat tests/runner-tests/hello_world.c
#include<stdio.h>
int main() {
puts("Hello, world!");
}
$ swcc --debug-ir tests/runner-tests/hello_world.c
function u0:0() -> i32 system_v {
gv0 = symbol colocated u1:3
sig0 = (i64) -> i32 system_v
fn0 = u0:26 sig0
block0:
v0 = global_value.i64 gv0
v1 = call fn0(v0)
v2 = iconst.i32 0
return v2
}
$ ./a.out
Hello, world!
$ swcc --help
swcc 0.9.0
Joshua Nelson <jyn514@gmail.com>
A C compiler written in Rust, with a focus on good error messages.
Homepage: https://github.com/jyn514/rcc/
usage: swcc [FLAGS] [OPTIONS] [<file>]
FLAGS:
--debug-ast If set, print the parsed abstract syntax tree (AST) in addition to compiling.
The AST does no type checking or validation, it only parses.
--debug-hir If set, print the high intermediate representation (HIR) in addition to compiling.
This does type checking and validation and also desugars various expressions.
--debug-ir If set, print the intermediate representation (IR) of the program in addition to compiling.
--debug-lex If set, print all tokens found by the lexer in addition to compiling.
--jit If set, will use JIT compilation for C code and instantly run compiled code (No files produced).
NOTE: this option only works if swcc was compiled with the `jit` feature.
-h, --help Prints help information
-c, --no-link If set, compile and assemble but do not link. Object file is machine-dependent.
-E, --preprocess-only If set, preprocess only, but do not do anything else.
Note that preprocessing discards whitespace and comments.
There is not currently a way to disable this behavior.
-V, --version Prints version information
OPTIONS:
--color <when> When to use color. May be "never", "auto", or "always". [default: auto]
-o, --output <output> The output file to use. [default: a.out]
--max-errors <max> The maximum number of errors to allow before giving up.
Use 0 to allow unlimited errors. [default: 10]
-I, --include <dir> Add a directory to the local include path (`#include "file.h"`).
Can be specified multiple times to add multiple directories.
-D, --define <id[=val]> Define an object-like macro.
Can be specified multiple times to add multiple macros.
`val` defaults to `1`.
ARGS:
<file> The file to read C source from. "-" means stdin (use ./- to read a file called '-').
Only one file at a time is currently accepted. [default: -]
cargo test
# optionally, you can fuzz the compiler
# it may be more helpful to just `grep -R unimplemented src`, though
# libFuzzer/AFL
tests/fuzz.sh
# Honggfuzz:
# Running Honggfuzz locally requires some parameters to use it at its full potential,
# so it is probably a good idea to have a look here: https://github.com/rust-fuzz/honggfuzz-rs/blob/master/README.md
# and here: https://github.com/google/honggfuzz/blob/master/docs/USAGE.md
# we suggest the following:
HFUZZ_RUN_ARGS="--tmout_sigvtalrm --exit_upon_crash" tests/hfuzz.sh
See FAQ.md
See CONTRIBUTING.md. This also includes reporting bugs.