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_candidates;
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_silent_emitter(
56                vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
57                format!("this error occurred on the command line: `--cfg={s}`"),
58                true,
59            );
60            let filename = FileName::cfg_spec_source_code(&s);
61
62            macro_rules! error {
63                ($reason: expr) => {
64                    #[allow(rustc::untranslatable_diagnostic)]
65                    #[allow(rustc::diagnostic_outside_of_impl)]
66                    dcx.fatal(format!(
67                        concat!("invalid `--cfg` argument: `{}` (", $reason, ")"),
68                        s
69                    ));
70                };
71            }
72
73            match new_parser_from_source_str(&psess, filename, s.to_string()) {
74                Ok(mut parser) => match parser.parse_meta_item(AllowLeadingUnsafe::No) {
75                    Ok(meta_item) if parser.token == token::Eof => {
76                        if meta_item.path.segments.len() != 1 {
77                            error!("argument key must be an identifier");
78                        }
79                        match &meta_item.kind {
80                            MetaItemKind::List(..) => {}
81                            MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
82                                error!("argument value must be a string");
83                            }
84                            MetaItemKind::NameValue(..) | MetaItemKind::Word => {
85                                let ident = meta_item.ident().expect("multi-segment cfg key");
86                                return (ident.name, meta_item.value_str());
87                            }
88                        }
89                    }
90                    Ok(..) => {}
91                    Err(err) => err.cancel(),
92                },
93                Err(errs) => errs.into_iter().for_each(|err| err.cancel()),
94            }
95
96            // If the user tried to use a key="value" flag, but is missing the quotes, provide
97            // a hint about how to resolve this.
98            if s.contains('=') && !s.contains("=\"") && !s.ends_with('"') {
99                error!(concat!(
100                    r#"expected `key` or `key="value"`, ensure escaping is appropriate"#,
101                    r#" for your shell, try 'key="value"' or key=\"value\""#
102                ));
103            } else {
104                error!(r#"expected `key` or `key="value"`"#);
105            }
106        })
107        .collect::<Cfg>()
108}
109
110/// Converts strings provided as `--check-cfg [specs]` into a `CheckCfg`.
111pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> CheckCfg {
112    // If any --check-cfg is passed then exhaustive_values and exhaustive_names
113    // are enabled by default.
114    let exhaustive_names = !specs.is_empty();
115    let exhaustive_values = !specs.is_empty();
116    let mut check_cfg = CheckCfg { exhaustive_names, exhaustive_values, ..CheckCfg::default() };
117
118    for s in specs {
119        let psess = ParseSess::with_silent_emitter(
120            vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
121            format!("this error occurred on the command line: `--check-cfg={s}`"),
122            true,
123        );
124        let filename = FileName::cfg_spec_source_code(&s);
125
126        const VISIT: &str =
127            "visit <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more details";
128
129        macro_rules! error {
130            ($reason:expr) => {
131                #[allow(rustc::untranslatable_diagnostic)]
132                #[allow(rustc::diagnostic_outside_of_impl)]
133                {
134                    let mut diag =
135                        dcx.struct_fatal(format!("invalid `--check-cfg` argument: `{s}`"));
136                    diag.note($reason);
137                    diag.note(VISIT);
138                    diag.emit()
139                }
140            };
141            (in $arg:expr, $reason:expr) => {
142                #[allow(rustc::untranslatable_diagnostic)]
143                #[allow(rustc::diagnostic_outside_of_impl)]
144                {
145                    let mut diag =
146                        dcx.struct_fatal(format!("invalid `--check-cfg` argument: `{s}`"));
147
148                    let pparg = rustc_ast_pretty::pprust::meta_list_item_to_string($arg);
149                    if let Some(lit) = $arg.lit() {
150                        let (lit_kind_article, lit_kind_descr) = {
151                            let lit_kind = lit.as_token_lit().kind;
152                            (lit_kind.article(), lit_kind.descr())
153                        };
154                        diag.note(format!(
155                            "`{pparg}` is {lit_kind_article} {lit_kind_descr} literal"
156                        ));
157                    } else {
158                        diag.note(format!("`{pparg}` is invalid"));
159                    }
160
161                    diag.note($reason);
162                    diag.note(VISIT);
163                    diag.emit()
164                }
165            };
166        }
167
168        let expected_error = || -> ! {
169            error!("expected `cfg(name, values(\"value1\", \"value2\", ... \"valueN\"))`")
170        };
171
172        let mut parser = match new_parser_from_source_str(&psess, filename, s.to_string()) {
173            Ok(parser) => parser,
174            Err(errs) => {
175                errs.into_iter().for_each(|err| err.cancel());
176                expected_error();
177            }
178        };
179
180        let meta_item = match parser.parse_meta_item(AllowLeadingUnsafe::No) {
181            Ok(meta_item) if parser.token == token::Eof => meta_item,
182            Ok(..) => expected_error(),
183            Err(err) => {
184                err.cancel();
185                expected_error();
186            }
187        };
188
189        let Some(args) = meta_item.meta_item_list() else {
190            expected_error();
191        };
192
193        if !meta_item.has_name(sym::cfg) {
194            expected_error();
195        }
196
197        let mut names = Vec::new();
198        let mut values: FxHashSet<_> = Default::default();
199
200        let mut any_specified = false;
201        let mut values_specified = false;
202        let mut values_any_specified = false;
203
204        for arg in args {
205            if arg.is_word()
206                && let Some(ident) = arg.ident()
207            {
208                if values_specified {
209                    error!("`cfg()` names cannot be after values");
210                }
211                names.push(ident);
212            } else if let Some(boolean) = arg.boolean_literal() {
213                if values_specified {
214                    error!("`cfg()` names cannot be after values");
215                }
216                names.push(rustc_span::Ident::new(
217                    if boolean { rustc_span::kw::True } else { rustc_span::kw::False },
218                    arg.span(),
219                ));
220            } else if arg.has_name(sym::any)
221                && let Some(args) = arg.meta_item_list()
222            {
223                if any_specified {
224                    error!("`any()` cannot be specified multiple times");
225                }
226                any_specified = true;
227                if !args.is_empty() {
228                    error!(in arg, "`any()` takes no argument");
229                }
230            } else if arg.has_name(sym::values)
231                && let Some(args) = arg.meta_item_list()
232            {
233                if names.is_empty() {
234                    error!("`values()` cannot be specified before the names");
235                } else if values_specified {
236                    error!("`values()` cannot be specified multiple times");
237                }
238                values_specified = true;
239
240                for arg in args {
241                    if let Some(LitKind::Str(s, _)) = arg.lit().map(|lit| &lit.kind) {
242                        values.insert(Some(*s));
243                    } else if arg.has_name(sym::any)
244                        && let Some(args) = arg.meta_item_list()
245                    {
246                        if values_any_specified {
247                            error!(in arg, "`any()` in `values()` cannot be specified multiple times");
248                        }
249                        values_any_specified = true;
250                        if !args.is_empty() {
251                            error!(in arg, "`any()` in `values()` takes no argument");
252                        }
253                    } else if arg.has_name(sym::none)
254                        && let Some(args) = arg.meta_item_list()
255                    {
256                        values.insert(None);
257                        if !args.is_empty() {
258                            error!(in arg, "`none()` in `values()` takes no argument");
259                        }
260                    } else {
261                        error!(in arg, "`values()` arguments must be string literals, `none()` or `any()`");
262                    }
263                }
264            } else {
265                error!(in arg, "`cfg()` arguments must be simple identifiers, `any()` or `values(...)`");
266            }
267        }
268
269        if !values_specified && !any_specified {
270            // `cfg(name)` is equivalent to `cfg(name, values(none()))` so add
271            // an implicit `none()`
272            values.insert(None);
273        } else if !values.is_empty() && values_any_specified {
274            error!(
275                "`values()` arguments cannot specify string literals and `any()` at the same time"
276            );
277        }
278
279        if any_specified {
280            if names.is_empty() && values.is_empty() && !values_specified && !values_any_specified {
281                check_cfg.exhaustive_names = false;
282            } else {
283                error!("`cfg(any())` can only be provided in isolation");
284            }
285        } else {
286            for name in names {
287                check_cfg
288                    .expecteds
289                    .entry(name.name)
290                    .and_modify(|v| match v {
291                        ExpectedValues::Some(v) if !values_any_specified => {
292                            v.extend(values.clone())
293                        }
294                        ExpectedValues::Some(_) => *v = ExpectedValues::Any,
295                        ExpectedValues::Any => {}
296                    })
297                    .or_insert_with(|| {
298                        if values_any_specified {
299                            ExpectedValues::Any
300                        } else {
301                            ExpectedValues::Some(values.clone())
302                        }
303                    });
304            }
305        }
306    }
307
308    check_cfg
309}
310
311/// The compiler configuration
312pub struct Config {
313    /// Command line options
314    pub opts: config::Options,
315
316    /// Unparsed cfg! configuration in addition to the default ones.
317    pub crate_cfg: Vec<String>,
318    pub crate_check_cfg: Vec<String>,
319
320    pub input: Input,
321    pub output_dir: Option<PathBuf>,
322    pub output_file: Option<OutFileName>,
323    pub ice_file: Option<PathBuf>,
324    /// Load files from sources other than the file system.
325    ///
326    /// Has no uses within this repository, but may be used in the future by
327    /// bjorn3 for "hooking rust-analyzer's VFS into rustc at some point for
328    /// running rustc without having to save". (See #102759.)
329    pub file_loader: Option<Box<dyn FileLoader + Send + Sync>>,
330    /// The list of fluent resources, used for lints declared with
331    /// [`Diagnostic`](rustc_errors::Diagnostic) and [`LintDiagnostic`](rustc_errors::LintDiagnostic).
332    pub locale_resources: Vec<&'static str>,
333
334    pub lint_caps: FxHashMap<lint::LintId, lint::Level>,
335
336    /// This is a callback from the driver that is called when [`ParseSess`] is created.
337    pub psess_created: Option<Box<dyn FnOnce(&mut ParseSess) + Send>>,
338
339    /// This is a callback to hash otherwise untracked state used by the caller, if the
340    /// hash changes between runs the incremental cache will be cleared.
341    ///
342    /// e.g. used by Clippy to hash its config file
343    pub hash_untracked_state: Option<Box<dyn FnOnce(&Session, &mut StableHasher) + Send>>,
344
345    /// This is a callback from the driver that is called when we're registering lints;
346    /// it is called during lint loading when we have the LintStore in a non-shared state.
347    ///
348    /// Note that if you find a Some here you probably want to call that function in the new
349    /// function being registered.
350    pub register_lints: Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>>,
351
352    /// This is a callback from the driver that is called just after we have populated
353    /// the list of queries.
354    pub override_queries: Option<fn(&Session, &mut Providers)>,
355
356    /// An extra set of symbols to add to the symbol interner, the symbol indices
357    /// will start at [`PREDEFINED_SYMBOLS_COUNT`](rustc_span::symbol::PREDEFINED_SYMBOLS_COUNT)
358    pub extra_symbols: Vec<&'static str>,
359
360    /// This is a callback from the driver that is called to create a codegen backend.
361    ///
362    /// Has no uses within this repository, but is used by bjorn3 for "the
363    /// hotswapping branch of cg_clif" for "setting the codegen backend from a
364    /// custom driver where the custom codegen backend has arbitrary data."
365    /// (See #102759.)
366    pub make_codegen_backend:
367        Option<Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>>,
368
369    /// Registry of diagnostics codes.
370    pub registry: Registry,
371
372    /// The inner atomic value is set to true when a feature marked as `internal` is
373    /// enabled. Makes it so that "please report a bug" is hidden, as ICEs with
374    /// internal features are wontfix, and they are usually the cause of the ICEs.
375    pub using_internal_features: &'static std::sync::atomic::AtomicBool,
376
377    /// All commandline args used to invoke the compiler, with @file args fully expanded.
378    /// This will only be used within debug info, e.g. in the pdb file on windows
379    /// This is mainly useful for other tools that reads that debuginfo to figure out
380    /// how to call the compiler with the same arguments.
381    pub expanded_args: Vec<String>,
382}
383
384/// Initialize jobserver before getting `jobserver::client` and `build_session`.
385pub(crate) fn initialize_checked_jobserver(early_dcx: &EarlyDiagCtxt) {
386    jobserver::initialize_checked(|err| {
387        #[allow(rustc::untranslatable_diagnostic)]
388        #[allow(rustc::diagnostic_outside_of_impl)]
389        early_dcx
390            .early_struct_warn(err)
391            .with_note("the build environment is likely misconfigured")
392            .emit()
393    });
394}
395
396// JUSTIFICATION: before session exists, only config
397#[allow(rustc::bad_opt_access)]
398pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Send) -> R {
399    trace!("run_compiler");
400
401    // Set parallel mode before thread pool creation, which will create `Lock`s.
402    rustc_data_structures::sync::set_dyn_thread_safe_mode(config.opts.unstable_opts.threads > 1);
403
404    // Check jobserver before run_in_thread_pool_with_globals, which call jobserver::acquire_thread
405    let early_dcx = EarlyDiagCtxt::new(config.opts.error_format);
406    initialize_checked_jobserver(&early_dcx);
407
408    crate::callbacks::setup_callbacks();
409
410    let sysroot = config.opts.sysroot.clone();
411    let target = config::build_target_config(&early_dcx, &config.opts.target_triple, &sysroot);
412    let file_loader = config.file_loader.unwrap_or_else(|| Box::new(RealFileLoader));
413    let path_mapping = config.opts.file_path_mapping();
414    let hash_kind = config.opts.unstable_opts.src_hash_algorithm(&target);
415    let checksum_hash_kind = config.opts.unstable_opts.checksum_hash_algorithm();
416
417    util::run_in_thread_pool_with_globals(
418        &early_dcx,
419        config.opts.edition,
420        config.opts.unstable_opts.threads,
421        &config.extra_symbols,
422        SourceMapInputs { file_loader, path_mapping, hash_kind, checksum_hash_kind },
423        |current_gcx, jobserver_proxy| {
424            // The previous `early_dcx` can't be reused here because it doesn't
425            // impl `Send`. Creating a new one is fine.
426            let early_dcx = EarlyDiagCtxt::new(config.opts.error_format);
427
428            let codegen_backend = match config.make_codegen_backend {
429                None => util::get_codegen_backend(
430                    &early_dcx,
431                    &sysroot,
432                    config.opts.unstable_opts.codegen_backend.as_deref(),
433                    &target,
434                ),
435                Some(make_codegen_backend) => {
436                    // N.B. `make_codegen_backend` takes precedence over
437                    // `target.default_codegen_backend`, which is ignored in this case.
438                    make_codegen_backend(&config.opts)
439                }
440            };
441
442            let temps_dir = config.opts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
443
444            let bundle = match rustc_errors::fluent_bundle(
445                config.opts.sysroot.clone(),
446                sysroot_candidates().to_vec(),
447                config.opts.unstable_opts.translate_lang.clone(),
448                config.opts.unstable_opts.translate_additional_ftl.as_deref(),
449                config.opts.unstable_opts.translate_directionality_markers,
450            ) {
451                Ok(bundle) => bundle,
452                Err(e) => {
453                    // We can't translate anything if we failed to load translations
454                    #[allow(rustc::untranslatable_diagnostic)]
455                    early_dcx.early_fatal(format!("failed to load fluent bundle: {e}"))
456                }
457            };
458
459            let mut locale_resources = config.locale_resources;
460            locale_resources.push(codegen_backend.locale_resource());
461
462            let mut sess = rustc_session::build_session(
463                config.opts,
464                CompilerIO {
465                    input: config.input,
466                    output_dir: config.output_dir,
467                    output_file: config.output_file,
468                    temps_dir,
469                },
470                bundle,
471                config.registry,
472                locale_resources,
473                config.lint_caps,
474                target,
475                sysroot,
476                util::rustc_version_str().unwrap_or("unknown"),
477                config.ice_file,
478                config.using_internal_features,
479                config.expanded_args,
480            );
481
482            codegen_backend.init(&sess);
483
484            let cfg = parse_cfg(sess.dcx(), config.crate_cfg);
485            let mut cfg = config::build_configuration(&sess, cfg);
486            util::add_configuration(&mut cfg, &mut sess, &*codegen_backend);
487            sess.psess.config = cfg;
488
489            let mut check_cfg = parse_check_cfg(sess.dcx(), config.crate_check_cfg);
490            check_cfg.fill_well_known(&sess.target);
491            sess.psess.check_config = check_cfg;
492
493            if let Some(psess_created) = config.psess_created {
494                psess_created(&mut sess.psess);
495            }
496
497            if let Some(hash_untracked_state) = config.hash_untracked_state {
498                let mut hasher = StableHasher::new();
499                hash_untracked_state(&sess, &mut hasher);
500                sess.opts.untracked_state_hash = hasher.finish()
501            }
502
503            // Even though the session holds the lint store, we can't build the
504            // lint store until after the session exists. And we wait until now
505            // so that `register_lints` sees the fully initialized session.
506            let mut lint_store = rustc_lint::new_lint_store(sess.enable_internal_lints());
507            if let Some(register_lints) = config.register_lints.as_deref() {
508                register_lints(&sess, &mut lint_store);
509            }
510            sess.lint_store = Some(Arc::new(lint_store));
511
512            util::check_abi_required_features(&sess);
513
514            let compiler = Compiler {
515                sess,
516                codegen_backend,
517                override_queries: config.override_queries,
518                current_gcx,
519                jobserver_proxy,
520            };
521
522            // There are two paths out of `f`.
523            // - Normal exit.
524            // - Panic, e.g. triggered by `abort_if_errors` or a fatal error.
525            //
526            // We must run `finish_diagnostics` in both cases.
527            let res = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| f(&compiler)));
528
529            compiler.sess.finish_diagnostics();
530
531            // If error diagnostics have been emitted, we can't return an
532            // error directly, because the return type of this function
533            // is `R`, not `Result<R, E>`. But we need to communicate the
534            // errors' existence to the caller, otherwise the caller might
535            // mistakenly think that no errors occurred and return a zero
536            // exit code. So we abort (panic) instead, similar to if `f`
537            // had panicked.
538            if res.is_ok() {
539                compiler.sess.dcx().abort_if_errors();
540            }
541
542            // Also make sure to flush delayed bugs as if we panicked, the
543            // bugs would be flushed by the Drop impl of DiagCtxt while
544            // unwinding, which would result in an abort with
545            // "panic in a destructor during cleanup".
546            compiler.sess.dcx().flush_delayed();
547
548            let res = match res {
549                Ok(res) => res,
550                // Resume unwinding if a panic happened.
551                Err(err) => std::panic::resume_unwind(err),
552            };
553
554            let prof = compiler.sess.prof.clone();
555            prof.generic_activity("drop_compiler").run(move || drop(compiler));
556
557            res
558        },
559    )
560}
561
562pub fn try_print_query_stack(
563    dcx: DiagCtxtHandle<'_>,
564    limit_frames: Option<usize>,
565    file: Option<std::fs::File>,
566) {
567    eprintln!("query stack during panic:");
568
569    // Be careful relying on global state here: this code is called from
570    // a panic hook, which means that the global `DiagCtxt` may be in a weird
571    // state if it was responsible for triggering the panic.
572    let all_frames = ty::tls::with_context_opt(|icx| {
573        if let Some(icx) = icx {
574            ty::print::with_no_queries!(print_query_stack(
575                QueryCtxt::new(icx.tcx),
576                icx.query,
577                dcx,
578                limit_frames,
579                file,
580            ))
581        } else {
582            0
583        }
584    });
585
586    if let Some(limit_frames) = limit_frames
587        && all_frames > limit_frames
588    {
589        eprintln!(
590            "... and {} other queries... use `env RUST_BACKTRACE=1` to see the full query stack",
591            all_frames - limit_frames
592        );
593    } else {
594        eprintln!("end of query stack");
595    }
596}
rustc_interface/interface.rs

rustc_interface/
interface.rs
