rust/src/driver.rs

// error-pattern:yummy
#![feature(box_syntax)]
#![feature(rustc_private)]
#![feature(tool_lints)]
#![allow(unknown_lints, clippy::missing_docs_in_private_items)]

// FIXME: switch to something more ergonomic here, once available.
// (currently there is no way to opt into sysroot crates w/o `extern crate`)
#[allow(unused_extern_crates)]
extern crate rustc_driver;
#[allow(unused_extern_crates)]
extern crate rustc_plugin;
use self::rustc_driver::{driver::CompileController, Compilation};

use std::path::Path;
use std::process::{exit, Command};

#[allow(clippy::print_stdout)]
fn show_version() {
    println!(env!("CARGO_PKG_VERSION"));
}

pub fn main() {
    exit(rustc_driver::run(move || {
        use std::env;

        if std::env::args().any(|a| a == "--version" || a == "-V") {
            show_version();
            exit(0);
        }

        let sys_root = option_env!("SYSROOT")
            .map(String::from)
            .or_else(|| std::env::var("SYSROOT").ok())
            .or_else(|| {
                let home = option_env!("RUSTUP_HOME").or(option_env!("MULTIRUST_HOME"));
                let toolchain = option_env!("RUSTUP_TOOLCHAIN").or(option_env!("MULTIRUST_TOOLCHAIN"));
                home.and_then(|home| toolchain.map(|toolchain| format!("{}/toolchains/{}", home, toolchain)))
            })
            .or_else(|| {
                Command::new("rustc")
                    .arg("--print")
                    .arg("sysroot")
                    .output()
                    .ok()
                    .and_then(|out| String::from_utf8(out.stdout).ok())
                    .map(|s| s.trim().to_owned())
            })
            .expect("need to specify SYSROOT env var during clippy compilation, or use rustup or multirust");

        // Setting RUSTC_WRAPPER causes Cargo to pass 'rustc' as the first argument.
        // We're invoking the compiler programmatically, so we ignore this/
        let mut orig_args: Vec<String> = env::args().collect();
        if orig_args.len() <= 1 {
            std::process::exit(1);
        }
        if Path::new(&orig_args[1]).file_stem() == Some("rustc".as_ref()) {
            // we still want to be able to invoke it normally though
            orig_args.remove(1);
        }
        // this conditional check for the --sysroot flag is there so users can call
        // `clippy_driver` directly
        // without having to pass --sysroot or anything
        let mut args: Vec<String> = if orig_args.iter().any(|s| s == "--sysroot") {
            orig_args.clone()
        } else {
            orig_args
                .clone()
                .into_iter()
                .chain(Some("--sysroot".to_owned()))
                .chain(Some(sys_root))
                .collect()
        };

        // this check ensures that dependencies are built but not linted and the final
        // crate is
        // linted but not built
        let clippy_enabled = env::var("CLIPPY_TESTS").ok().map_or(false, |val| val == "true")
            || orig_args.iter().any(|s| s == "--emit=dep-info,metadata");

        if clippy_enabled {
            args.extend_from_slice(&["--cfg".to_owned(), r#"feature="cargo-clippy""#.to_owned()]);
            if let Ok(extra_args) = env::var("CLIPPY_ARGS") {
                args.extend(
                    extra_args
                        .split("__CLIPPY_HACKERY__")
                        .filter_map(|s| if s.is_empty() {
                            None
                        } else {
                            Some(s.to_string())
                        })
                );
            }
        }

        let mut controller = CompileController::basic();
        if clippy_enabled {
            controller.after_parse.callback = Box::new(move |state| {
                let mut registry = rustc_plugin::registry::Registry::new(
                    state.session,
                    state
                        .krate
                        .as_ref()
                        .expect(
                            "at this compilation stage \
                            the crate must be parsed",
                        )
                        .span,
                );
                registry.args_hidden = Some(Vec::new());

                let conf = clippy_lints::read_conf(&registry);
                clippy_lints::register_plugins(&mut registry, &conf);

                let rustc_plugin::registry::Registry {
                    early_lint_passes,
                    late_lint_passes,
                    lint_groups,
                    llvm_passes,
                    attributes,
                    ..
                } = registry;
                let sess = &state.session;
                let mut ls = sess.lint_store.borrow_mut();
                for pass in early_lint_passes {
                    ls.register_early_pass(Some(sess), true, pass);
                }
                for pass in late_lint_passes {
                    ls.register_late_pass(Some(sess), true, pass);
                }

                for (name, (to, deprecated_name)) in lint_groups {
                    ls.register_group(Some(sess), true, name, deprecated_name, to);
                }
                clippy_lints::register_pre_expansion_lints(sess, &mut ls, &conf);

                sess.plugin_llvm_passes.borrow_mut().extend(llvm_passes);
                sess.plugin_attributes.borrow_mut().extend(attributes);
            });
        }
        controller.compilation_done.stop = Compilation::Stop;

        let args = args;
        rustc_driver::run_compiler(&args, Box::new(controller), None, None)
    }) as i32)
}