Check in generated bindgen bindings (#52)

* Check in generated bindgen bindings

This commit checks in the bindgen-generated bindings for the binaryen
project, along with a test that ensures that the generated bindings are
up to date and don't need to be regenerated. Additionally you can run
tests locally with `BLESS=1` to regenerate the header file to
automatically generate it.

* Add diff output to test

* Only bind some functions

.travis.yml

@@ -21,6 +21,7 @@ env:
   - CC=clang CXX=clang++
   - CC=gcc-7 CXX=g++-7
 script:
+  - rustup component add rustfmt
   - cargo build --all --verbose
   # Run tests with --test-threads=1 as it looks like the linker runs out of memory
   # when linking doctests in parallel.

binaryen-sys/Cargo.toml

@@ -12,8 +12,11 @@ exclude = [
 ]
 
 [build-dependencies]
-bindgen = "0.52.0"
 cmake = "0.1.25"
 cc = "1.0.4"
 regex = "1"
 heck = "0.3"
+
+[dev-dependencies]
+bindgen = "0.52.0"
+diff = "0.1"

binaryen-sys/build.rs

@@ -1,4 +1,3 @@
-extern crate bindgen;
 extern crate cc;
 extern crate cmake;
 extern crate heck;
@@ -11,23 +10,6 @@ use std::fs;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 
-fn gen_bindings() {
-    let bindings = bindgen::Builder::default()
-        .header("wrapper.h")
-        // See https://github.com/rust-lang-nursery/rust-bindgen/issues/947
-        .trust_clang_mangling(false)
-        .generate_comments(true)
-        // https://github.com/rust-lang-nursery/rust-bindgen/issues/947#issuecomment-327100002
-        .layout_tests(false)
-        .generate()
-        .expect("Unable to generate bindings");
-
-    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
-    bindings
-        .write_to_file(out_path.join("bindings.rs"))
-        .expect("Couldn't write bindings!");
-}
-
 #[derive(Clone, PartialEq, Debug)]
 struct Pass {
     id: String,
@@ -156,7 +138,6 @@ fn main() {
     }
 
     gen_passes();
-    gen_bindings();
 
     let target = env::var("TARGET").ok();
     if target.map_or(false, |target| target.contains("emscripten")) {