rustc_interface/
interface.rs

1use std::path::PathBuf;
2use std::result;
3use std::sync::Arc;
4
5use rustc_ast::{LitKind, MetaItemKind, token};
6use rustc_codegen_ssa::traits::CodegenBackend;
7use rustc_data_structures::fx::{FxHashMap, FxHashSet};
8use rustc_data_structures::jobserver::{self, Proxy};
9use rustc_data_structures::stable_hasher::StableHasher;
10use rustc_errors::registry::Registry;
11use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed};
12use rustc_lint::LintStore;
13use rustc_middle::ty;
14use rustc_middle::ty::CurrentGcx;
15use rustc_middle::util::Providers;
16use rustc_parse::new_parser_from_source_str;
17use rustc_parse::parser::attr::AllowLeadingUnsafe;
18use rustc_query_impl::QueryCtxt;
19use rustc_query_system::query::print_query_stack;
20use rustc_session::config::{self, Cfg, CheckCfg, ExpectedValues, Input, OutFileName};
21use rustc_session::filesearch::sysroot_with_fallback;
22use rustc_session::parse::ParseSess;
23use rustc_session::{CompilerIO, EarlyDiagCtxt, Session, lint};
24use rustc_span::source_map::{FileLoader, RealFileLoader, SourceMapInputs};
25use rustc_span::{FileName, sym};
26use tracing::trace;
27
28use crate::util;
29
30pub type Result<T> = result::Result<T, ErrorGuaranteed>;
31
32/// Represents a compiler session. Note that every `Compiler` contains a
33/// `Session`, but `Compiler` also contains some things that cannot be in
34/// `Session`, due to `Session` being in a crate that has many fewer
35/// dependencies than this crate.
36///
37/// Can be used to run `rustc_interface` queries.
38/// Created by passing [`Config`] to [`run_compiler`].
39pub struct Compiler {
40    pub sess: Session,
41    pub codegen_backend: Box<dyn CodegenBackend>,
42    pub(crate) override_queries: Option<fn(&Session, &mut Providers)>,
43
44    /// A reference to the current `GlobalCtxt` which we pass on to `GlobalCtxt`.
45    pub(crate) current_gcx: CurrentGcx,
46
47    /// A jobserver reference which we pass on to `GlobalCtxt`.
48    pub(crate) jobserver_proxy: Arc<Proxy>,
49}
50
51/// Converts strings provided as `--cfg [cfgspec]` into a `Cfg`.
52pub(crate) fn parse_cfg(dcx: DiagCtxtHandle<'_>, cfgs: Vec<String>) -> Cfg {
53    cfgs.into_iter()
54        .map(|s| {
55            let psess = ParseSess::with_fatal_emitter(
56                vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
57                format!("this error occurred on the command line: `--cfg={s}`"),
58            );
59            let filename = FileName::cfg_spec_source_code(&s);
60
61            macro_rules! error {
62                ($reason: expr) => {
63                    #[allow(rustc::untranslatable_diagnostic)]
64                    #[allow(rustc::diagnostic_outside_of_impl)]
65                    dcx.fatal(format!(
66                        concat!("invalid `--cfg` argument: `{}` (", $reason, ")"),
67                        s
68                    ));
69                };
70            }
71
72            match new_parser_from_source_str(&psess, filename, s.to_string()) {
73                Ok(mut parser) => match parser.parse_meta_item(AllowLeadingUnsafe::No) {
74                    Ok(meta_item) if parser.token == token::Eof => {
75                        if meta_item.path.segments.len() != 1 {
76                            error!("argument key must be an identifier");
77                        }
78                        match &meta_item.kind {
79                            MetaItemKind::List(..) => {}
80                            MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
81                                error!("argument value must be a string");
82                            }
83                            MetaItemKind::NameValue(..) | MetaItemKind::Word => {
84                                let ident = meta_item.ident().expect("multi-segment cfg key");
85                                return (ident.name, meta_item.value_str());
86                            }
87                        }
88                    }
89                    Ok(..) => {}
90                    Err(err) => err.cancel(),
91                },
92                Err(errs) => errs.into_iter().for_each(|err| err.cancel()),
93            }
94
95            // If the user tried to use a key="value" flag, but is missing the quotes, provide
96            // a hint about how to resolve this.
97            if s.contains('=') && !s.contains("=\"") && !s.ends_with('"') {
98                error!(concat!(
99                    r#"expected `key` or `key="value"`, ensure escaping is appropriate"#,
100                    r#" for your shell, try 'key="value"' or key=\"value\""#
101                ));
102            } else {
103                error!(r#"expected `key` or `key="value"`"#);
104            }
105        })
106        .collect::<Cfg>()
107}
108
109/// Converts strings provided as `--check-cfg [specs]` into a `CheckCfg`.
110pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> CheckCfg {
111    // If any --check-cfg is passed then exhaustive_values and exhaustive_names
112    // are enabled by default.
113    let exhaustive_names = !specs.is_empty();
114    let exhaustive_values = !specs.is_empty();
115    let mut check_cfg = CheckCfg { exhaustive_names, exhaustive_values, ..CheckCfg::default() };
116
117    for s in specs {
118        let psess = ParseSess::with_fatal_emitter(
119            vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
120            format!("this error occurred on the command line: `--check-cfg={s}`"),
121        );
122        let filename = FileName::cfg_spec_source_code(&s);
123
124        const VISIT: &str =
125            "visit <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more details";
126
127        macro_rules! error {
128            ($reason:expr) => {
129                #[allow(rustc::untranslatable_diagnostic)]
130                #[allow(rustc::diagnostic_outside_of_impl)]
131                {
132                    let mut diag =
133                        dcx.struct_fatal(format!("invalid `--check-cfg` argument: `{s}`"));
134                    diag.note($reason);
135                    diag.note(VISIT);
136                    diag.emit()
137                }
138            };
139            (in $arg:expr, $reason:expr) => {
140                #[allow(rustc::untranslatable_diagnostic)]
141                #[allow(rustc::diagnostic_outside_of_impl)]
142                {
143                    let mut diag =
144                        dcx.struct_fatal(format!("invalid `--check-cfg` argument: `{s}`"));
145
146                    let pparg = rustc_ast_pretty::pprust::meta_list_item_to_string($arg);
147                    if let Some(lit) = $arg.lit() {
148                        let (lit_kind_article, lit_kind_descr) = {
149                            let lit_kind = lit.as_token_lit().kind;
150                            (lit_kind.article(), lit_kind.descr())
151                        };
152                        diag.note(format!(
153                            "`{pparg}` is {lit_kind_article} {lit_kind_descr} literal"
154                        ));
155                    } else {
156                        diag.note(format!("`{pparg}` is invalid"));
157                    }
158
159                    diag.note($reason);
160                    diag.note(VISIT);
161                    diag.emit()
162                }
163            };
164        }
165
166        let expected_error = || -> ! {
167            error!("expected `cfg(name, values(\"value1\", \"value2\", ... \"valueN\"))`")
168        };
169
170        let mut parser = match new_parser_from_source_str(&psess, filename, s.to_string()) {
171            Ok(parser) => parser,
172            Err(errs) => {
173                errs.into_iter().for_each(|err| err.cancel());
174                expected_error();
175            }
176        };
177
178        let meta_item = match parser.parse_meta_item(AllowLeadingUnsafe::No) {
179            Ok(meta_item) if parser.token == token::Eof => meta_item,
180            Ok(..) => expected_error(),
181            Err(err) => {
182                err.cancel();
183                expected_error();
184            }
185        };
186
187        let Some(args) = meta_item.meta_item_list() else {
188            expected_error();
189        };
190
191        if !meta_item.has_name(sym::cfg) {
192            expected_error();
193        }
194
195        let mut names = Vec::new();
196        let mut values: FxHashSet<_> = Default::default();
197
198        let mut any_specified = false;
199        let mut values_specified = false;
200        let mut values_any_specified = false;
201
202        for arg in args {
203            if arg.is_word()
204                && let Some(ident) = arg.ident()
205            {
206                if values_specified {
207                    error!("`cfg()` names cannot be after values");
208                }
209                names.push(ident);
210            } else if let Some(boolean) = arg.boolean_literal() {
211                if values_specified {
212                    error!("`cfg()` names cannot be after values");
213                }
214                names.push(rustc_span::Ident::new(
215                    if boolean { rustc_span::kw::True } else { rustc_span::kw::False },
216                    arg.span(),
217                ));
218            } else if arg.has_name(sym::any)
219                && let Some(args) = arg.meta_item_list()
220            {
221                if any_specified {
222                    error!("`any()` cannot be specified multiple times");
223                }
224                any_specified = true;
225                if !args.is_empty() {
226                    error!(in arg, "`any()` takes no argument");
227                }
228            } else if arg.has_name(sym::values)
229                && let Some(args) = arg.meta_item_list()
230            {
231                if names.is_empty() {
232                    error!("`values()` cannot be specified before the names");
233                } else if values_specified {
234                    error!("`values()` cannot be specified multiple times");
235                }
236                values_specified = true;
237
238                for arg in args {
239                    if let Some(LitKind::Str(s, _)) = arg.lit().map(|lit| &lit.kind) {
240                        values.insert(Some(*s));
241                    } else if arg.has_name(sym::any)
242                        && let Some(args) = arg.meta_item_list()
243                    {
244                        if values_any_specified {
245                            error!(in arg, "`any()` in `values()` cannot be specified multiple times");
246                        }
247                        values_any_specified = true;
248                        if !args.is_empty() {
249                            error!(in arg, "`any()` in `values()` takes no argument");
250                        }
251                    } else if arg.has_name(sym::none)
252                        && let Some(args) = arg.meta_item_list()
253                    {
254                        values.insert(None);
255                        if !args.is_empty() {
256                            error!(in arg, "`none()` in `values()` takes no argument");
257                        }
258                    } else {
259                        error!(in arg, "`values()` arguments must be string literals, `none()` or `any()`");
260                    }
261                }
262            } else {
263                error!(in arg, "`cfg()` arguments must be simple identifiers, `any()` or `values(...)`");
264            }
265        }
266
267        if !values_specified && !any_specified {
268            // `cfg(name)` is equivalent to `cfg(name, values(none()))` so add
269            // an implicit `none()`
270            values.insert(None);
271        } else if !values.is_empty() && values_any_specified {
272            error!(
273                "`values()` arguments cannot specify string literals and `any()` at the same time"
274            );
275        }
276
277        if any_specified {
278            if names.is_empty() && values.is_empty() && !values_specified && !values_any_specified {
279                check_cfg.exhaustive_names = false;
280            } else {
281                error!("`cfg(any())` can only be provided in isolation");
282            }
283        } else {
284            for name in names {
285                check_cfg
286                    .expecteds
287                    .entry(name.name)
288                    .and_modify(|v| match v {
289                        ExpectedValues::Some(v) if !values_any_specified => {
290                            v.extend(values.clone())
291                        }
292                        ExpectedValues::Some(_) => *v = ExpectedValues::Any,
293                        ExpectedValues::Any => {}
294                    })
295                    .or_insert_with(|| {
296                        if values_any_specified {
297                            ExpectedValues::Any
298                        } else {
299                            ExpectedValues::Some(values.clone())
300                        }
301                    });
302            }
303        }
304    }
305
306    check_cfg
307}
308
309/// The compiler configuration
310pub struct Config {
311    /// Command line options
312    pub opts: config::Options,
313
314    /// Unparsed cfg! configuration in addition to the default ones.
315    pub crate_cfg: Vec<String>,
316    pub crate_check_cfg: Vec<String>,
317
318    pub input: Input,
319    pub output_dir: Option<PathBuf>,
320    pub output_file: Option<OutFileName>,
321    pub ice_file: Option<PathBuf>,
322    /// Load files from sources other than the file system.
323    ///
324    /// Has no uses within this repository, but may be used in the future by
325    /// bjorn3 for "hooking rust-analyzer's VFS into rustc at some point for
326    /// running rustc without having to save". (See #102759.)
327    pub file_loader: Option<Box<dyn FileLoader + Send + Sync>>,
328    /// The list of fluent resources, used for lints declared with
329    /// [`Diagnostic`](rustc_errors::Diagnostic) and [`LintDiagnostic`](rustc_errors::LintDiagnostic).
330    pub locale_resources: Vec<&'static str>,
331
332    pub lint_caps: FxHashMap<lint::LintId, lint::Level>,
333
334    /// This is a callback from the driver that is called when [`ParseSess`] is created.
335    pub psess_created: Option<Box<dyn FnOnce(&mut ParseSess) + Send>>,
336
337    /// This is a callback to hash otherwise untracked state used by the caller, if the
338    /// hash changes between runs the incremental cache will be cleared.
339    ///
340    /// e.g. used by Clippy to hash its config file
341    pub hash_untracked_state: Option<Box<dyn FnOnce(&Session, &mut StableHasher) + Send>>,
342
343    /// This is a callback from the driver that is called when we're registering lints;
344    /// it is called during lint loading when we have the LintStore in a non-shared state.
345    ///
346    /// Note that if you find a Some here you probably want to call that function in the new
347    /// function being registered.
348    pub register_lints: Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>>,
349
350    /// This is a callback from the driver that is called just after we have populated
351    /// the list of queries.
352    pub override_queries: Option<fn(&Session, &mut Providers)>,
353
354    /// An extra set of symbols to add to the symbol interner, the symbol indices
355    /// will start at [`PREDEFINED_SYMBOLS_COUNT`](rustc_span::symbol::PREDEFINED_SYMBOLS_COUNT)
356    pub extra_symbols: Vec<&'static str>,
357
358    /// This is a callback from the driver that is called to create a codegen backend.
359    ///
360    /// Has no uses within this repository, but is used by bjorn3 for "the
361    /// hotswapping branch of cg_clif" for "setting the codegen backend from a
362    /// custom driver where the custom codegen backend has arbitrary data."
363    /// (See #102759.)
364    pub make_codegen_backend:
365        Option<Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>>,
366
367    /// Registry of diagnostics codes.
368    pub registry: Registry,
369
370    /// The inner atomic value is set to true when a feature marked as `internal` is
371    /// enabled. Makes it so that "please report a bug" is hidden, as ICEs with
372    /// internal features are wontfix, and they are usually the cause of the ICEs.
373    pub using_internal_features: &'static std::sync::atomic::AtomicBool,
374
375    /// All commandline args used to invoke the compiler, with @file args fully expanded.
376    /// This will only be used within debug info, e.g. in the pdb file on windows
377    /// This is mainly useful for other tools that reads that debuginfo to figure out
378    /// how to call the compiler with the same arguments.
379    pub expanded_args: Vec<String>,
380}
381
382/// Initialize jobserver before getting `jobserver::client` and `build_session`.
383pub(crate) fn initialize_checked_jobserver(early_dcx: &EarlyDiagCtxt) {
384    jobserver::initialize_checked(|err| {
385        #[allow(rustc::untranslatable_diagnostic)]
386        #[allow(rustc::diagnostic_outside_of_impl)]
387        early_dcx
388            .early_struct_warn(err)
389            .with_note("the build environment is likely misconfigured")
390            .emit()
391    });
392}
393
394// JUSTIFICATION: before session exists, only config
395#[allow(rustc::bad_opt_access)]
396pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Send) -> R {
397    trace!("run_compiler");
398
399    // Set parallel mode before thread pool creation, which will create `Lock`s.
400    rustc_data_structures::sync::set_dyn_thread_safe_mode(config.opts.unstable_opts.threads > 1);
401
402    // Check jobserver before run_in_thread_pool_with_globals, which call jobserver::acquire_thread
403    let early_dcx = EarlyDiagCtxt::new(config.opts.error_format);
404    initialize_checked_jobserver(&early_dcx);
405
406    crate::callbacks::setup_callbacks();
407
408    let sysroot = config.opts.sysroot.clone();
409    let target = config::build_target_config(&early_dcx, &config.opts.target_triple, &sysroot);
410    let file_loader = config.file_loader.unwrap_or_else(|| Box::new(RealFileLoader));
411    let path_mapping = config.opts.file_path_mapping();
412    let hash_kind = config.opts.unstable_opts.src_hash_algorithm(&target);
413    let checksum_hash_kind = config.opts.unstable_opts.checksum_hash_algorithm();
414
415    util::run_in_thread_pool_with_globals(
416        &early_dcx,
417        config.opts.edition,
418        config.opts.unstable_opts.threads,
419        &config.extra_symbols,
420        SourceMapInputs { file_loader, path_mapping, hash_kind, checksum_hash_kind },
421        |current_gcx, jobserver_proxy| {
422            // The previous `early_dcx` can't be reused here because it doesn't
423            // impl `Send`. Creating a new one is fine.
424            let early_dcx = EarlyDiagCtxt::new(config.opts.error_format);
425
426            let codegen_backend = match config.make_codegen_backend {
427                None => util::get_codegen_backend(
428                    &early_dcx,
429                    &sysroot,
430                    config.opts.unstable_opts.codegen_backend.as_deref(),
431                    &target,
432                ),
433                Some(make_codegen_backend) => {
434                    // N.B. `make_codegen_backend` takes precedence over
435                    // `target.default_codegen_backend`, which is ignored in this case.
436                    make_codegen_backend(&config.opts)
437                }
438            };
439
440            let temps_dir = config.opts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
441
442            let bundle = match rustc_errors::fluent_bundle(
443                sysroot_with_fallback(&config.opts.sysroot),
444                config.opts.unstable_opts.translate_lang.clone(),
445                config.opts.unstable_opts.translate_additional_ftl.as_deref(),
446                config.opts.unstable_opts.translate_directionality_markers,
447            ) {
448                Ok(bundle) => bundle,
449                Err(e) => {
450                    // We can't translate anything if we failed to load translations
451                    #[allow(rustc::untranslatable_diagnostic)]
452                    early_dcx.early_fatal(format!("failed to load fluent bundle: {e}"))
453                }
454            };
455
456            let mut locale_resources = config.locale_resources;
457            locale_resources.push(codegen_backend.locale_resource());
458
459            let mut sess = rustc_session::build_session(
460                config.opts,
461                CompilerIO {
462                    input: config.input,
463                    output_dir: config.output_dir,
464                    output_file: config.output_file,
465                    temps_dir,
466                },
467                bundle,
468                config.registry,
469                locale_resources,
470                config.lint_caps,
471                target,
472                sysroot,
473                util::rustc_version_str().unwrap_or("unknown"),
474                config.ice_file,
475                config.using_internal_features,
476                config.expanded_args,
477            );
478
479            codegen_backend.init(&sess);
480
481            let cfg = parse_cfg(sess.dcx(), config.crate_cfg);
482            let mut cfg = config::build_configuration(&sess, cfg);
483            util::add_configuration(&mut cfg, &mut sess, &*codegen_backend);
484            sess.psess.config = cfg;
485
486            let mut check_cfg = parse_check_cfg(sess.dcx(), config.crate_check_cfg);
487            check_cfg.fill_well_known(&sess.target);
488            sess.psess.check_config = check_cfg;
489
490            if let Some(psess_created) = config.psess_created {
491                psess_created(&mut sess.psess);
492            }
493
494            if let Some(hash_untracked_state) = config.hash_untracked_state {
495                let mut hasher = StableHasher::new();
496                hash_untracked_state(&sess, &mut hasher);
497                sess.opts.untracked_state_hash = hasher.finish()
498            }
499
500            // Even though the session holds the lint store, we can't build the
501            // lint store until after the session exists. And we wait until now
502            // so that `register_lints` sees the fully initialized session.
503            let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
504            if let Some(register_lints) = config.register_lints.as_deref() {
505                register_lints(&sess, &mut lint_store);
506            }
507            sess.lint_store = Some(Arc::new(lint_store));
508
509            util::check_abi_required_features(&sess);
510
511            let compiler = Compiler {
512                sess,
513                codegen_backend,
514                override_queries: config.override_queries,
515                current_gcx,
516                jobserver_proxy,
517            };
518
519            // There are two paths out of `f`.
520            // - Normal exit.
521            // - Panic, e.g. triggered by `abort_if_errors` or a fatal error.
522            //
523            // We must run `finish_diagnostics` in both cases.
524            let res = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| f(&compiler)));
525
526            compiler.sess.finish_diagnostics();
527
528            // If error diagnostics have been emitted, we can't return an
529            // error directly, because the return type of this function
530            // is `R`, not `Result<R, E>`. But we need to communicate the
531            // errors' existence to the caller, otherwise the caller might
532            // mistakenly think that no errors occurred and return a zero
533            // exit code. So we abort (panic) instead, similar to if `f`
534            // had panicked.
535            if res.is_ok() {
536                compiler.sess.dcx().abort_if_errors();
537            }
538
539            // Also make sure to flush delayed bugs as if we panicked, the
540            // bugs would be flushed by the Drop impl of DiagCtxt while
541            // unwinding, which would result in an abort with
542            // "panic in a destructor during cleanup".
543            compiler.sess.dcx().flush_delayed();
544
545            let res = match res {
546                Ok(res) => res,
547                // Resume unwinding if a panic happened.
548                Err(err) => std::panic::resume_unwind(err),
549            };
550
551            let prof = compiler.sess.prof.clone();
552            prof.generic_activity("drop_compiler").run(move || drop(compiler));
553
554            res
555        },
556    )
557}
558
559pub fn try_print_query_stack(
560    dcx: DiagCtxtHandle<'_>,
561    limit_frames: Option<usize>,
562    file: Option<std::fs::File>,
563) {
564    eprintln!("query stack during panic:");
565
566    // Be careful relying on global state here: this code is called from
567    // a panic hook, which means that the global `DiagCtxt` may be in a weird
568    // state if it was responsible for triggering the panic.
569    let all_frames = ty::tls::with_context_opt(|icx| {
570        if let Some(icx) = icx {
571            ty::print::with_no_queries!(print_query_stack(
572                QueryCtxt::new(icx.tcx),
573                icx.query,
574                dcx,
575                limit_frames,
576                file,
577            ))
578        } else {
579            0
580        }
581    });
582
583    if let Some(limit_frames) = limit_frames
584        && all_frames > limit_frames
585    {
586        eprintln!(
587            "... and {} other queries... use `env RUST_BACKTRACE=1` to see the full query stack",
588            all_frames - limit_frames
589        );
590    } else {
591        eprintln!("end of query stack");
592    }
593}
rustc_interface/interface.rs

rustc_interface/
interface.rs
