src/tools/clippy/src/driver.rs

   1 #![feature(rustc_private)]
   2 #![feature(once_cell)]
   3 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
   4 // warn on lints, that are included in `rust-lang/rust`s bootstrap
   5 #![warn(rust_2018_idioms, unused_lifetimes)]
   6 // warn on rustc internal lints
   7 #![warn(rustc::internal)]
   8
   9 // FIXME: switch to something more ergonomic here, once available.
  10 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
  11 extern crate rustc_driver;
  12 extern crate rustc_errors;
  13 extern crate rustc_interface;
  14 extern crate rustc_session;
  15 extern crate rustc_span;
  16
  17 use rustc_interface::interface;
  18 use rustc_session::parse::ParseSess;
  19 use rustc_span::symbol::Symbol;
  20 use rustc_tools_util::VersionInfo;
  21
  22 use std::borrow::Cow;
  23 use std::env;
  24 use std::lazy::SyncLazy;
  25 use std::ops::Deref;
  26 use std::panic;
  27 use std::path::{Path, PathBuf};
  28 use std::process::{exit, Command};
  29
  30 /// If a command-line option matches `find_arg`, then apply the predicate `pred` on its value. If
  31 /// true, then return it. The parameter is assumed to be either `--arg=value` or `--arg value`.
  32 fn arg_value<'a, T: Deref<Target = str>>(
  33     args: &'a [T],
  34     find_arg: &str,
  35     pred: impl Fn(&str) -> bool,
  36 ) -> Option<&'a str> {
  37     let mut args = args.iter().map(Deref::deref);
  38     while let Some(arg) = args.next() {
  39         let mut arg = arg.splitn(2, '=');
  40         if arg.next() != Some(find_arg) {
  41             continue;
  42         }
  43
  44         match arg.next().or_else(|| args.next()) {
  45             Some(v) if pred(v) => return Some(v),
  46             _ => {},
  47         }
  48     }
  49     None
  50 }
  51
  52 #[test]
  53 fn test_arg_value() {
  54     let args = &["--bar=bar", "--foobar", "123", "--foo"];
  55
  56     assert_eq!(arg_value(&[] as &[&str], "--foobar", |_| true), None);
  57     assert_eq!(arg_value(args, "--bar", |_| false), None);
  58     assert_eq!(arg_value(args, "--bar", |_| true), Some("bar"));
  59     assert_eq!(arg_value(args, "--bar", |p| p == "bar"), Some("bar"));
  60     assert_eq!(arg_value(args, "--bar", |p| p == "foo"), None);
  61     assert_eq!(arg_value(args, "--foobar", |p| p == "foo"), None);
  62     assert_eq!(arg_value(args, "--foobar", |p| p == "123"), Some("123"));
  63     assert_eq!(arg_value(args, "--foo", |_| true), None);
  64 }
  65
  66 fn track_clippy_args(parse_sess: &mut ParseSess, args_env_var: &Option<String>) {
  67     parse_sess.env_depinfo.get_mut().insert((
  68         Symbol::intern("CLIPPY_ARGS"),
  69         args_env_var.as_deref().map(Symbol::intern),
  70     ));
  71 }
  72
  73 struct DefaultCallbacks;
  74 impl rustc_driver::Callbacks for DefaultCallbacks {}
  75
  76 /// This is different from `DefaultCallbacks` that it will inform Cargo to track the value of
  77 /// `CLIPPY_ARGS` environment variable.
  78 struct RustcCallbacks {
  79     clippy_args_var: Option<String>,
  80 }
  81
  82 impl rustc_driver::Callbacks for RustcCallbacks {
  83     fn config(&mut self, config: &mut interface::Config) {
  84         let clippy_args_var = self.clippy_args_var.take();
  85         config.parse_sess_created = Some(Box::new(move |parse_sess| {
  86             track_clippy_args(parse_sess, &clippy_args_var);
  87         }));
  88     }
  89 }
  90
  91 struct ClippyCallbacks {
  92     clippy_args_var: Option<String>,
  93 }
  94
  95 impl rustc_driver::Callbacks for ClippyCallbacks {
  96     fn config(&mut self, config: &mut interface::Config) {
  97         let previous = config.register_lints.take();
  98         let clippy_args_var = self.clippy_args_var.take();
  99         config.parse_sess_created = Some(Box::new(move |parse_sess| {
 100             track_clippy_args(parse_sess, &clippy_args_var);
 101         }));
 102         config.register_lints = Some(Box::new(move |sess, lint_store| {
 103             // technically we're ~guaranteed that this is none but might as well call anything that
 104             // is there already. Certainly it can't hurt.
 105             if let Some(previous) = &previous {
 106                 (previous)(sess, lint_store);
 107             }
 108
 109             let conf = clippy_lints::read_conf(sess);
 110             clippy_lints::register_plugins(lint_store, sess, &conf);
 111             clippy_lints::register_pre_expansion_lints(lint_store, sess, &conf);
 112             clippy_lints::register_renamed(lint_store);
 113         }));
 114
 115         // FIXME: #4825; This is required, because Clippy lints that are based on MIR have to be
 116         // run on the unoptimized MIR. On the other hand this results in some false negatives. If
 117         // MIR passes can be enabled / disabled separately, we should figure out, what passes to
 118         // use for Clippy.
 119         config.opts.debugging_opts.mir_opt_level = Some(0);
 120     }
 121 }
 122
 123 fn display_help() {
 124     println!(
 125         "\
 126 Checks a package to catch common mistakes and improve your Rust code.
 127
 128 Usage:
 129     cargo clippy [options] [--] [<opts>...]
 130
 131 Common options:
 132     -h, --help               Print this message
 133         --rustc              Pass all args to rustc
 134     -V, --version            Print version info and exit
 135
 136 Other options are the same as `cargo check`.
 137
 138 To allow or deny a lint from the command line you can use `cargo clippy --`
 139 with:
 140
 141     -W --warn OPT       Set lint warnings
 142     -A --allow OPT      Set lint allowed
 143     -D --deny OPT       Set lint denied
 144     -F --forbid OPT     Set lint forbidden
 145
 146 You can use tool lints to allow or deny lints from your code, eg.:
 147
 148     #[allow(clippy::needless_lifetimes)]
 149 "
 150     );
 151 }
 152
 153 const BUG_REPORT_URL: &str = "https://github.com/rust-lang/rust-clippy/issues/new";
 154
 155 static ICE_HOOK: SyncLazy<Box<dyn Fn(&panic::PanicInfo<'_>) + Sync + Send + 'static>> = SyncLazy::new(|| {
 156     let hook = panic::take_hook();
 157     panic::set_hook(Box::new(|info| report_clippy_ice(info, BUG_REPORT_URL)));
 158     hook
 159 });
 160
 161 fn report_clippy_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str) {
 162     // Invoke our ICE handler, which prints the actual panic message and optionally a backtrace
 163     (*ICE_HOOK)(info);
 164
 165     // Separate the output with an empty line
 166     eprintln!();
 167
 168     let fallback_bundle = rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
 169     let emitter = Box::new(rustc_errors::emitter::EmitterWriter::stderr(
 170         rustc_errors::ColorConfig::Auto,
 171         None,
 172         None,
 173         fallback_bundle,
 174         false,
 175         false,
 176         None,
 177         false,
 178     ));
 179     let handler = rustc_errors::Handler::with_emitter(true, None, emitter);
 180
 181     // a .span_bug or .bug call has already printed what
 182     // it wants to print.
 183     if !info.payload().is::<rustc_errors::ExplicitBug>() {
 184         let mut d = rustc_errors::Diagnostic::new(rustc_errors::Level::Bug, "unexpected panic");
 185         handler.emit_diagnostic(&mut d);
 186     }
 187
 188     let version_info = rustc_tools_util::get_version_info!();
 189
 190     let xs: Vec<Cow<'static, str>> = vec![
 191         "the compiler unexpectedly panicked. this is a bug.".into(),
 192         format!("we would appreciate a bug report: {}", bug_report_url).into(),
 193         format!("Clippy version: {}", version_info).into(),
 194     ];
 195
 196     for note in &xs {
 197         handler.note_without_error(note.as_ref());
 198     }
 199
 200     // If backtraces are enabled, also print the query stack
 201     let backtrace = env::var_os("RUST_BACKTRACE").map_or(false, |x| &x != "0");
 202
 203     let num_frames = if backtrace { None } else { Some(2) };
 204
 205     interface::try_print_query_stack(&handler, num_frames);
 206 }
 207
 208 fn toolchain_path(home: Option<String>, toolchain: Option<String>) -> Option<PathBuf> {
 209     home.and_then(|home| {
 210         toolchain.map(|toolchain| {
 211             let mut path = PathBuf::from(home);
 212             path.push("toolchains");
 213             path.push(toolchain);
 214             path
 215         })
 216     })
 217 }
 218
 219 #[allow(clippy::too_many_lines)]
 220 pub fn main() {
 221     rustc_driver::init_rustc_env_logger();
 222     SyncLazy::force(&ICE_HOOK);
 223     exit(rustc_driver::catch_with_exit_code(move || {
 224         let mut orig_args: Vec<String> = env::args().collect();
 225
 226         // Get the sysroot, looking from most specific to this invocation to the least:
 227         // - command line
 228         // - runtime environment
 229         //    - SYSROOT
 230         //    - RUSTUP_HOME, MULTIRUST_HOME, RUSTUP_TOOLCHAIN, MULTIRUST_TOOLCHAIN
 231         // - sysroot from rustc in the path
 232         // - compile-time environment
 233         //    - SYSROOT
 234         //    - RUSTUP_HOME, MULTIRUST_HOME, RUSTUP_TOOLCHAIN, MULTIRUST_TOOLCHAIN
 235         let sys_root_arg = arg_value(&orig_args, "--sysroot", |_| true);
 236         let have_sys_root_arg = sys_root_arg.is_some();
 237         let sys_root = sys_root_arg
 238             .map(PathBuf::from)
 239             .or_else(|| std::env::var("SYSROOT").ok().map(PathBuf::from))
 240             .or_else(|| {
 241                 let home = std::env::var("RUSTUP_HOME")
 242                     .or_else(|_| std::env::var("MULTIRUST_HOME"))
 243                     .ok();
 244                 let toolchain = std::env::var("RUSTUP_TOOLCHAIN")
 245                     .or_else(|_| std::env::var("MULTIRUST_TOOLCHAIN"))
 246                     .ok();
 247                 toolchain_path(home, toolchain)
 248             })
 249             .or_else(|| {
 250                 Command::new("rustc")
 251                     .arg("--print")
 252                     .arg("sysroot")
 253                     .output()
 254                     .ok()
 255                     .and_then(|out| String::from_utf8(out.stdout).ok())
 256                     .map(|s| PathBuf::from(s.trim()))
 257             })
 258             .or_else(|| option_env!("SYSROOT").map(PathBuf::from))
 259             .or_else(|| {
 260                 let home = option_env!("RUSTUP_HOME")
 261                     .or(option_env!("MULTIRUST_HOME"))
 262                     .map(ToString::to_string);
 263                 let toolchain = option_env!("RUSTUP_TOOLCHAIN")
 264                     .or(option_env!("MULTIRUST_TOOLCHAIN"))
 265                     .map(ToString::to_string);
 266                 toolchain_path(home, toolchain)
 267             })
 268             .map(|pb| pb.to_string_lossy().to_string())
 269             .expect("need to specify SYSROOT env var during clippy compilation, or use rustup or multirust");
 270
 271         // make "clippy-driver --rustc" work like a subcommand that passes further args to "rustc"
 272         // for example `clippy-driver --rustc --version` will print the rustc version that clippy-driver
 273         // uses
 274         if let Some(pos) = orig_args.iter().position(|arg| arg == "--rustc") {
 275             orig_args.remove(pos);
 276             orig_args[0] = "rustc".to_string();
 277
 278             // if we call "rustc", we need to pass --sysroot here as well
 279             let mut args: Vec<String> = orig_args.clone();
 280             if !have_sys_root_arg {
 281                 args.extend(vec!["--sysroot".into(), sys_root]);
 282             };
 283
 284             return rustc_driver::RunCompiler::new(&args, &mut DefaultCallbacks).run();
 285         }
 286
 287         if orig_args.iter().any(|a| a == "--version" || a == "-V") {
 288             let version_info = rustc_tools_util::get_version_info!();
 289             println!("{}", version_info);
 290             exit(0);
 291         }
 292
 293         // Setting RUSTC_WRAPPER causes Cargo to pass 'rustc' as the first argument.
 294         // We're invoking the compiler programmatically, so we ignore this/
 295         let wrapper_mode = orig_args.get(1).map(Path::new).and_then(Path::file_stem) == Some("rustc".as_ref());
 296
 297         if wrapper_mode {
 298             // we still want to be able to invoke it normally though
 299             orig_args.remove(1);
 300         }
 301
 302         if !wrapper_mode && (orig_args.iter().any(|a| a == "--help" || a == "-h") || orig_args.len() == 1) {
 303             display_help();
 304             exit(0);
 305         }
 306
 307         // this conditional check for the --sysroot flag is there so users can call
 308         // `clippy_driver` directly
 309         // without having to pass --sysroot or anything
 310         let mut args: Vec<String> = orig_args.clone();
 311         if !have_sys_root_arg {
 312             args.extend(vec!["--sysroot".into(), sys_root]);
 313         };
 314
 315         let mut no_deps = false;
 316         let clippy_args_var = env::var("CLIPPY_ARGS").ok();
 317         let clippy_args = clippy_args_var
 318             .as_deref()
 319             .unwrap_or_default()
 320             .split("__CLIPPY_HACKERY__")
 321             .filter_map(|s| match s {
 322                 "" => None,
 323                 "--no-deps" => {
 324                     no_deps = true;
 325                     None
 326                 },
 327                 _ => Some(s.to_string()),
 328             })
 329             .chain(vec!["--cfg".into(), r#"feature="cargo-clippy""#.into()])
 330             .collect::<Vec<String>>();
 331
 332         // We enable Clippy if one of the following conditions is met
 333         // - IF Clippy is run on its test suite OR
 334         // - IF Clippy is run on the main crate, not on deps (`!cap_lints_allow`) THEN
 335         //    - IF `--no-deps` is not set (`!no_deps`) OR
 336         //    - IF `--no-deps` is set and Clippy is run on the specified primary package
 337         let cap_lints_allow = arg_value(&orig_args, "--cap-lints", |val| val == "allow").is_some();
 338         let in_primary_package = env::var("CARGO_PRIMARY_PACKAGE").is_ok();
 339
 340         let clippy_enabled = !cap_lints_allow && (!no_deps || in_primary_package);
 341         if clippy_enabled {
 342             args.extend(clippy_args);
 343         }
 344
 345         if clippy_enabled {
 346             rustc_driver::RunCompiler::new(&args, &mut ClippyCallbacks { clippy_args_var }).run()
 347         } else {
 348             rustc_driver::RunCompiler::new(&args, &mut RustcCallbacks { clippy_args_var }).run()
 349         }
 350     }))
 351 }