Auto merge of #940 - fitzgen:no-syntex, r=emilio

No more syntex

There are a few commits in this PR, but the big one is the commit that goes `syntex` -> `quote` for code generation. I've included a copy of its commit message below.

I tried to verify that it works with the stylo build still, but there were some issues, and then I checked with master, and that wasn't working either. So now I'm C-Reducing the failures on master and figured that this is at least ready for feedback in the meantime.

r? @emilio

----------------------------

The `syntex` crate is unmaintained. It is slow to build, and additionally it requires that we pre-process `src/codegen/mod.rs` before we build the `bindgen` crate.

The `quote` crate provides similar quasi-quoting functionality, is maintained, and builds faster. It doesn't have a typed API or builders, however; it only deals with tokens.

Before this commit:

```
$ cargo clean; cargo build
<snip>
    Finished dev [unoptimized + debuginfo] target(s) in 98.75 secs
```

After this commit:

```
$ cargo clean; cargo build
<snip>
    Finished dev [unoptimized + debuginfo] target(s) in 46.26 secs
```

Build time is cut in half! But what about run time?

Before this commit:

```
Generated Stylo bindings in: Duration { secs: 3, nanos: 521105668 }
```

After this commit:

```
Generated Stylo bindings in: Duration { secs: 3, nanos: 548797242 }
```

So it appears to be about 20ms slower at generating Stylo bindings, but I suspect this is well within the noise.

Finally, this also lets us remove that nasty `mem::transmute` inside `bindgen::ir::BindgenContext::gen` that was used for the old `syntex` context. Now `BindgenContext` doesn't have a lifetime parameter either. This should make it easier to revisit doing our analyses in parallel with `rayon`, since that context was one of the things that made it hard for `BindgenContext` to implement `Sync`.

Fixes #925

Author: bors-servo

CONTRIBUTING.md

@@ -88,6 +88,14 @@ There is also the `./bindgen-integration` crate, which uses `bindgen` to
 generate bindings to some C++ code, and then uses the bindings, asserting that
 values are what we expect them to be both on the Rust and C++ side.
 
+The generated and expected bindings are run through `rustfmt` before they are
+compared. Make sure you have `rustfmt` up to date:
+
+```
+$ rustup update nightly
+$ rustup run nightly cargo install -f rustfmt-nightly
+```
+
 ### Testing Bindings Generation
 
 To regenerate bindings from the corpus of test headers in `tests/headers` and

Cargo.lock

@@ -39,25 +39,18 @@ diff = "0.1"
 clap = "2"
 shlex = "0.1"
 
-[build-dependencies]
-quasi_codegen = "0.32"
-
 [dependencies]
 cexpr = "0.2"
 cfg-if = "0.1.0"
+# This kinda sucks: https://github.com/rust-lang/cargo/issues/1982
+clap = "2"
 clang-sys = { version = "0.19.0", features = ["runtime", "clang_3_9"] }
 lazy_static = "0.2.1"
 peeking_take_while = "0.1.2"
-syntex_syntax = "0.58"
+quote = "0.3.15"
 regex = "0.2"
-# This kinda sucks: https://github.com/rust-lang/cargo/issues/1982
-clap = "2"
 which = "1.0.2"
 
-[dependencies.aster]
-features = ["with-syntex"]
-version = "0.41"
-
 [dependencies.env_logger]
 optional = true
 version = "0.4"
@@ -66,10 +59,6 @@ version = "0.4"
 optional = true
 version = "0.3"
 
-[dependencies.quasi]
-features = ["with-syntex"]
-version = "0.32"
-
 [features]
 default = ["logging"]
 logging = ["env_logger", "log"]

Cargo.toml

@@ -1,20 +1,11 @@
-mod codegen {
-    extern crate quasi_codegen;
+mod target {
     use std::env;
     use std::fs::File;
     use std::io::Write;
     use std::path::{Path, PathBuf};
 
     pub fn main() {
         let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-        let src = Path::new("src/codegen/mod.rs");
-        let dst = Path::new(&out_dir).join("codegen.rs");
-
-        quasi_codegen::expand(&src, &dst).unwrap();
-        println!("cargo:rerun-if-changed=src/codegen/mod.rs");
-        println!("cargo:rerun-if-changed=src/codegen/error.rs");
-        println!("cargo:rerun-if-changed=src/codegen/helpers.rs");
-        println!("cargo:rerun-if-changed=src/codegen/struct_layout.rs");
 
         let mut dst = File::create(Path::new(&out_dir).join("host-target.txt"))
             .unwrap();
@@ -77,6 +68,6 @@ mod testgen {
 }
 
 fn main() {
-    codegen::main();
+    target::main();
     testgen::main();
 }

build.rs

@@ -11,6 +11,10 @@ export RUST_BACKTRACE=1
 
 case "$BINDGEN_JOB" in
     "test")
+        # Need rustfmt to compare the test expectations.
+        rustup update nightly
+        rustup run nightly cargo install -f rustfmt-nightly
+
         cargo test $BINDGEN_PROFILE --features "$BINDGEN_FEATURES"
         ./ci/assert-no-diff.sh
         ;;