rust/src/driver.rs

// error-pattern:yummy
#![feature(box_syntax)]
#![feature(rustc_private)]
#![feature(try_from)]
#![allow(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::convert::TryInto;
use std::path::Path;
use std::process::{exit, Command};

fn show_version() {
    println!(env!("CARGO_PKG_VERSION"));
}

pub fn main() {
    rustc_driver::init_rustc_env_logger();
    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);
                    clippy_lints::register_renamed(&mut ls);

                    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)
        })
        .try_into()
        .expect("exit code too large"),
    )
}