2 use rustc::session::config::{Input, OutputFilenames, ErrorOutputType};
3 use rustc::session::{self, config, early_error, filesearch, Session, DiagnosticOutput};
4 use rustc::session::CrateDisambiguator;
7 use rustc_codegen_utils::codegen_backend::CodegenBackend;
8 #[cfg(parallel_compiler)]
9 use rustc_data_structures::jobserver;
10 use rustc_data_structures::sync::{Lock, Lrc};
11 use rustc_data_structures::stable_hasher::StableHasher;
12 use rustc_data_structures::fingerprint::Fingerprint;
13 use rustc_data_structures::thin_vec::ThinVec;
14 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
15 use rustc_errors::registry::Registry;
17 use rustc_metadata::dynamic_lib::DynamicLibrary;
25 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
26 use std::io::{self, Write};
28 use std::path::{Path, PathBuf};
29 use std::sync::atomic::{AtomicBool, Ordering};
30 use std::sync::{Arc, Mutex, Once};
31 use std::ops::DerefMut;
32 use smallvec::SmallVec;
34 use syntax::mut_visit::{*, MutVisitor, visit_clobber};
35 use syntax::ast::BlockCheckMode;
36 use syntax::util::lev_distance::find_best_match_for_name;
37 use syntax::source_map::{FileLoader, RealFileLoader, SourceMap};
38 use syntax::symbol::{Symbol, sym};
39 use syntax::{self, ast, attr};
40 use syntax_pos::edition::Edition;
41 #[cfg(not(parallel_compiler))]
42 use std::{thread, panic};
44 pub fn diagnostics_registry() -> Registry {
45 let mut all_errors = Vec::new();
46 all_errors.extend_from_slice(&rustc::DIAGNOSTICS);
47 all_errors.extend_from_slice(&rustc_typeck::DIAGNOSTICS);
48 all_errors.extend_from_slice(&rustc_resolve::DIAGNOSTICS);
49 all_errors.extend_from_slice(&rustc_privacy::DIAGNOSTICS);
50 // FIXME: need to figure out a way to get these back in here
51 // all_errors.extend_from_slice(get_codegen_backend(sess).diagnostics());
52 all_errors.extend_from_slice(&rustc_metadata::DIAGNOSTICS);
53 all_errors.extend_from_slice(&rustc_passes::DIAGNOSTICS);
54 all_errors.extend_from_slice(&rustc_plugin::DIAGNOSTICS);
55 all_errors.extend_from_slice(&rustc_mir::DIAGNOSTICS);
56 all_errors.extend_from_slice(&syntax::DIAGNOSTICS);
58 Registry::new(&all_errors)
61 /// Adds `target_feature = "..."` cfgs for a variety of platform
62 /// specific features (SSE, NEON etc.).
64 /// This is performed by checking whether a whitelisted set of
65 /// features is available on the target machine, by querying LLVM.
66 pub fn add_configuration(
67 cfg: &mut ast::CrateConfig,
69 codegen_backend: &dyn CodegenBackend,
71 let tf = sym::target_feature;
75 .target_features(sess)
77 .map(|feat| (tf, Some(feat))),
80 if sess.crt_static_feature() {
81 cfg.insert((tf, Some(Symbol::intern("crt-static"))));
85 pub fn create_session(
86 sopts: config::Options,
87 cfg: FxHashSet<(String, Option<String>)>,
88 diagnostic_output: DiagnosticOutput,
89 file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
90 input_path: Option<PathBuf>,
91 lint_caps: FxHashMap<lint::LintId, lint::Level>,
92 ) -> (Lrc<Session>, Lrc<Box<dyn CodegenBackend>>, Lrc<SourceMap>) {
93 let descriptions = diagnostics_registry();
95 let loader = file_loader.unwrap_or(box RealFileLoader);
96 let source_map = Lrc::new(SourceMap::with_file_loader(
98 sopts.file_path_mapping(),
100 let mut sess = session::build_session_with_source_map(
109 let codegen_backend = get_codegen_backend(&sess);
111 rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
112 if sess.unstable_options() {
113 rustc_lint::register_internals(&mut sess.lint_store.borrow_mut(), Some(&sess));
116 let mut cfg = config::build_configuration(&sess, config::to_crate_config(cfg));
117 add_configuration(&mut cfg, &sess, &*codegen_backend);
118 sess.parse_sess.config = cfg;
120 (Lrc::new(sess), Lrc::new(codegen_backend), source_map)
123 // Temporarily have stack size set to 32MB to deal with various crates with long method
124 // chains or deep syntax trees, except when on Haiku.
125 // FIXME(oli-obk): get https://github.com/rust-lang/rust/pull/55617 the finish line
126 #[cfg(not(target_os = "haiku"))]
127 const STACK_SIZE: usize = 32 * 1024 * 1024;
129 #[cfg(target_os = "haiku")]
130 const STACK_SIZE: usize = 16 * 1024 * 1024;
132 fn get_stack_size() -> Option<usize> {
133 // FIXME: Hacks on hacks. If the env is trying to override the stack size
134 // then *don't* set it explicitly.
135 if env::var_os("RUST_MIN_STACK").is_none() {
142 struct Sink(Arc<Mutex<Vec<u8>>>);
143 impl Write for Sink {
144 fn write(&mut self, data: &[u8]) -> io::Result<usize> {
145 Write::write(&mut *self.0.lock().unwrap(), data)
147 fn flush(&mut self) -> io::Result<()> { Ok(()) }
150 #[cfg(not(parallel_compiler))]
151 pub fn scoped_thread<F: FnOnce() -> R + Send, R: Send>(cfg: thread::Builder, f: F) -> R {
153 unsafe impl Send for Ptr {}
154 unsafe impl Sync for Ptr {}
157 let run = Ptr(&mut f as *mut _ as *mut ());
158 let mut result = None;
159 let result_ptr = Ptr(&mut result as *mut _ as *mut ());
161 let thread = cfg.spawn(move || {
162 let run = unsafe { (*(run.0 as *mut Option<F>)).take().unwrap() };
163 let result = unsafe { &mut *(result_ptr.0 as *mut Option<R>) };
164 *result = Some(run());
167 match thread.unwrap().join() {
168 Ok(()) => result.unwrap(),
169 Err(p) => panic::resume_unwind(p),
173 #[cfg(not(parallel_compiler))]
174 pub fn spawn_thread_pool<F: FnOnce() -> R + Send, R: Send>(
176 _threads: Option<usize>,
177 stderr: &Option<Arc<Mutex<Vec<u8>>>>,
180 let mut cfg = thread::Builder::new().name("rustc".to_string());
182 if let Some(size) = get_stack_size() {
183 cfg = cfg.stack_size(size);
186 scoped_thread(cfg, || {
187 syntax::with_globals(edition, || {
188 ty::tls::GCX_PTR.set(&Lock::new(0), || {
189 if let Some(stderr) = stderr {
190 io::set_panic(Some(box Sink(stderr.clone())));
192 ty::tls::with_thread_locals(|| f())
198 #[cfg(parallel_compiler)]
199 pub fn spawn_thread_pool<F: FnOnce() -> R + Send, R: Send>(
201 threads: Option<usize>,
202 stderr: &Option<Arc<Mutex<Vec<u8>>>>,
205 use rayon::{ThreadPool, ThreadPoolBuilder};
209 let gcx_ptr = &Lock::new(0);
211 let mut config = ThreadPoolBuilder::new()
212 .acquire_thread_handler(jobserver::acquire_thread)
213 .release_thread_handler(jobserver::release_thread)
214 .num_threads(Session::threads_from_count(threads))
215 .deadlock_handler(|| unsafe { ty::query::handle_deadlock() });
217 if let Some(size) = get_stack_size() {
218 config = config.stack_size(size);
221 let with_pool = move |pool: &ThreadPool| pool.install(move || f());
223 syntax::with_globals(edition, || {
224 syntax::GLOBALS.with(|syntax_globals| {
225 syntax_pos::GLOBALS.with(|syntax_pos_globals| {
226 // The main handler runs for each Rayon worker thread and sets up
227 // the thread local rustc uses. syntax_globals and syntax_pos_globals are
228 // captured and set on the new threads. ty::tls::with_thread_locals sets up
229 // thread local callbacks from libsyntax
230 let main_handler = move |worker: &mut dyn FnMut()| {
231 syntax::GLOBALS.set(syntax_globals, || {
232 syntax_pos::GLOBALS.set(syntax_pos_globals, || {
233 if let Some(stderr) = stderr {
234 io::set_panic(Some(box Sink(stderr.clone())));
236 ty::tls::with_thread_locals(|| {
237 ty::tls::GCX_PTR.set(gcx_ptr, || worker())
243 ThreadPool::scoped_pool(config, main_handler, with_pool).unwrap()
249 fn load_backend_from_dylib(path: &Path) -> fn() -> Box<dyn CodegenBackend> {
250 let lib = DynamicLibrary::open(Some(path)).unwrap_or_else(|err| {
251 let err = format!("couldn't load codegen backend {:?}: {:?}", path, err);
252 early_error(ErrorOutputType::default(), &err);
255 match lib.symbol("__rustc_codegen_backend") {
258 mem::transmute::<*mut u8, _>(f)
261 let err = format!("couldn't load codegen backend as it \
262 doesn't export the `__rustc_codegen_backend` \
264 early_error(ErrorOutputType::default(), &err);
270 pub fn get_codegen_backend(sess: &Session) -> Box<dyn CodegenBackend> {
271 static INIT: Once = Once::new();
273 static mut LOAD: fn() -> Box<dyn CodegenBackend> = || unreachable!();
276 let codegen_name = sess.opts.debugging_opts.codegen_backend.as_ref()
277 .unwrap_or(&sess.target.target.options.codegen_backend);
278 let backend = match &codegen_name[..] {
279 filename if filename.contains(".") => {
280 load_backend_from_dylib(filename.as_ref())
282 codegen_name => get_codegen_sysroot(codegen_name),
289 let backend = unsafe { LOAD() };
294 pub fn get_codegen_sysroot(backend_name: &str) -> fn() -> Box<dyn CodegenBackend> {
295 // For now we only allow this function to be called once as it'll dlopen a
296 // few things, which seems to work best if we only do that once. In
297 // general this assertion never trips due to the once guard in `get_codegen_backend`,
298 // but there's a few manual calls to this function in this file we protect
300 static LOADED: AtomicBool = AtomicBool::new(false);
301 assert!(!LOADED.fetch_or(true, Ordering::SeqCst),
302 "cannot load the default codegen backend twice");
304 let target = session::config::host_triple();
305 let mut sysroot_candidates = vec![filesearch::get_or_default_sysroot()];
306 let path = current_dll_path()
307 .and_then(|s| s.canonicalize().ok());
308 if let Some(dll) = path {
309 // use `parent` twice to chop off the file name and then also the
310 // directory containing the dll which should be either `lib` or `bin`.
311 if let Some(path) = dll.parent().and_then(|p| p.parent()) {
312 // The original `path` pointed at the `rustc_driver` crate's dll.
313 // Now that dll should only be in one of two locations. The first is
314 // in the compiler's libdir, for example `$sysroot/lib/*.dll`. The
315 // other is the target's libdir, for example
316 // `$sysroot/lib/rustlib/$target/lib/*.dll`.
318 // We don't know which, so let's assume that if our `path` above
319 // ends in `$target` we *could* be in the target libdir, and always
320 // assume that we may be in the main libdir.
321 sysroot_candidates.push(path.to_owned());
323 if path.ends_with(target) {
324 sysroot_candidates.extend(path.parent() // chop off `$target`
325 .and_then(|p| p.parent()) // chop off `rustlib`
326 .and_then(|p| p.parent()) // chop off `lib`
327 .map(|s| s.to_owned()));
332 let sysroot = sysroot_candidates.iter()
334 let libdir = filesearch::relative_target_lib_path(&sysroot, &target);
335 sysroot.join(libdir).with_file_name(
336 option_env!("CFG_CODEGEN_BACKENDS_DIR").unwrap_or("codegen-backends"))
339 info!("codegen backend candidate: {}", f.display());
343 let sysroot = sysroot.unwrap_or_else(|| {
344 let candidates = sysroot_candidates.iter()
345 .map(|p| p.display().to_string())
348 let err = format!("failed to find a `codegen-backends` folder \
349 in the sysroot candidates:\n* {}", candidates);
350 early_error(ErrorOutputType::default(), &err);
352 info!("probing {} for a codegen backend", sysroot.display());
354 let d = sysroot.read_dir().unwrap_or_else(|e| {
355 let err = format!("failed to load default codegen backend, couldn't \
356 read `{}`: {}", sysroot.display(), e);
357 early_error(ErrorOutputType::default(), &err);
360 let mut file: Option<PathBuf> = None;
362 let expected_name = format!("rustc_codegen_llvm-{}", backend_name);
363 for entry in d.filter_map(|e| e.ok()) {
364 let path = entry.path();
365 let filename = match path.file_name().and_then(|s| s.to_str()) {
369 if !(filename.starts_with(DLL_PREFIX) && filename.ends_with(DLL_SUFFIX)) {
372 let name = &filename[DLL_PREFIX.len() .. filename.len() - DLL_SUFFIX.len()];
373 if name != expected_name {
376 if let Some(ref prev) = file {
377 let err = format!("duplicate codegen backends found\n\
380 ", prev.display(), path.display());
381 early_error(ErrorOutputType::default(), &err);
383 file = Some(path.clone());
387 Some(ref s) => return load_backend_from_dylib(s),
389 let err = format!("failed to load default codegen backend for `{}`, \
390 no appropriate codegen dylib found in `{}`",
391 backend_name, sysroot.display());
392 early_error(ErrorOutputType::default(), &err);
397 fn current_dll_path() -> Option<PathBuf> {
398 use std::ffi::{OsStr, CStr};
399 use std::os::unix::prelude::*;
402 let addr = current_dll_path as usize as *mut _;
403 let mut info = mem::zeroed();
404 if libc::dladdr(addr, &mut info) == 0 {
405 info!("dladdr failed");
408 if info.dli_fname.is_null() {
409 info!("dladdr returned null pointer");
412 let bytes = CStr::from_ptr(info.dli_fname).to_bytes();
413 let os = OsStr::from_bytes(bytes);
414 Some(PathBuf::from(os))
419 fn current_dll_path() -> Option<PathBuf> {
420 use std::ffi::OsString;
421 use std::os::windows::prelude::*;
424 fn GetModuleHandleExW(dwFlags: u32,
426 phModule: *mut usize) -> i32;
427 fn GetModuleFileNameW(hModule: usize,
428 lpFilename: *mut u16,
432 const GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS: u32 = 0x00000004;
436 let r = GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
437 current_dll_path as usize,
440 info!("GetModuleHandleExW failed: {}", io::Error::last_os_error());
443 let mut space = Vec::with_capacity(1024);
444 let r = GetModuleFileNameW(module,
446 space.capacity() as u32);
448 info!("GetModuleFileNameW failed: {}", io::Error::last_os_error());
452 if r >= space.capacity() {
453 info!("our buffer was too small? {}",
454 io::Error::last_os_error());
458 let os = OsString::from_wide(&space);
459 Some(PathBuf::from(os))
464 pub(crate) fn compute_crate_disambiguator(session: &Session) -> CrateDisambiguator {
465 use std::hash::Hasher;
467 // The crate_disambiguator is a 128 bit hash. The disambiguator is fed
468 // into various other hashes quite a bit (symbol hashes, incr. comp. hashes,
469 // debuginfo type IDs, etc), so we don't want it to be too wide. 128 bits
470 // should still be safe enough to avoid collisions in practice.
471 let mut hasher = StableHasher::<Fingerprint>::new();
473 let mut metadata = session.opts.cg.metadata.clone();
474 // We don't want the crate_disambiguator to dependent on the order
475 // -C metadata arguments, so sort them:
477 // Every distinct -C metadata value is only incorporated once:
480 hasher.write(b"metadata");
482 // Also incorporate the length of a metadata string, so that we generate
483 // different values for `-Cmetadata=ab -Cmetadata=c` and
484 // `-Cmetadata=a -Cmetadata=bc`
485 hasher.write_usize(s.len());
486 hasher.write(s.as_bytes());
489 // Also incorporate crate type, so that we don't get symbol conflicts when
490 // linking against a library of the same name, if this is an executable.
494 .contains(&config::CrateType::Executable);
495 hasher.write(if is_exe { b"exe" } else { b"lib" });
497 CrateDisambiguator::from(hasher.finish())
500 pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<config::CrateType> {
501 // Unconditionally collect crate types from attributes to make them used
502 let attr_types: Vec<config::CrateType> = attrs
505 if a.check_name(sym::crate_type) {
506 match a.value_str() {
507 Some(sym::rlib) => Some(config::CrateType::Rlib),
508 Some(sym::dylib) => Some(config::CrateType::Dylib),
509 Some(sym::cdylib) => Some(config::CrateType::Cdylib),
510 Some(sym::lib) => Some(config::default_lib_output()),
511 Some(sym::staticlib) => Some(config::CrateType::Staticlib),
512 Some(sym::proc_dash_macro) => Some(config::CrateType::ProcMacro),
513 Some(sym::bin) => Some(config::CrateType::Executable),
515 let crate_types = vec![
521 sym::proc_dash_macro,
525 if let ast::MetaItemKind::NameValue(spanned) = a.meta().unwrap().node {
526 let span = spanned.span;
527 let lev_candidate = find_best_match_for_name(
532 if let Some(candidate) = lev_candidate {
533 session.buffer_lint_with_diagnostic(
534 lint::builtin::UNKNOWN_CRATE_TYPES,
537 "invalid `crate_type` value",
538 lint::builtin::BuiltinLintDiagnostics::
541 "did you mean".to_string(),
542 format!("\"{}\"", candidate)
547 lint::builtin::UNKNOWN_CRATE_TYPES,
550 "invalid `crate_type` value"
564 // If we're generating a test executable, then ignore all other output
565 // styles at all other locations
566 if session.opts.test {
567 return vec![config::CrateType::Executable];
570 // Only check command line flags if present. If no types are specified by
571 // command line, then reuse the empty `base` Vec to hold the types that
572 // will be found in crate attributes.
573 let mut base = session.opts.crate_types.clone();
575 base.extend(attr_types);
577 base.push(::rustc_codegen_utils::link::default_output_for_target(
586 base.retain(|crate_type| {
587 let res = !::rustc_codegen_utils::link::invalid_output_for_target(session, *crate_type);
590 session.warn(&format!(
591 "dropping unsupported crate type `{}` for target `{}`",
592 *crate_type, session.opts.target_triple
602 pub fn build_output_filenames(
604 odir: &Option<PathBuf>,
605 ofile: &Option<PathBuf>,
606 attrs: &[ast::Attribute],
608 ) -> OutputFilenames {
611 // "-" as input file will cause the parser to read from stdin so we
612 // have to make up a name
613 // We want to toss everything after the final '.'
614 let dirpath = (*odir).as_ref().cloned().unwrap_or_default();
616 // If a crate name is present, we use it as the link name
620 .or_else(|| attr::find_crate_name(attrs).map(|n| n.to_string()))
621 .unwrap_or_else(|| input.filestem().to_owned());
624 out_directory: dirpath,
626 single_output_file: None,
627 extra: sess.opts.cg.extra_filename.clone(),
628 outputs: sess.opts.output_types.clone(),
632 Some(ref out_file) => {
633 let unnamed_output_types = sess.opts
636 .filter(|a| a.is_none())
638 let ofile = if unnamed_output_types > 1 {
640 "due to multiple output types requested, the explicitly specified \
641 output file name will be adapted for each output type",
645 Some(out_file.clone())
648 sess.warn("ignoring --out-dir flag due to -o flag");
650 if !sess.opts.cg.extra_filename.is_empty() {
651 sess.warn("ignoring -C extra-filename flag due to -o flag");
655 out_directory: out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
656 out_filestem: out_file
662 single_output_file: ofile,
663 extra: sess.opts.cg.extra_filename.clone(),
664 outputs: sess.opts.output_types.clone(),
670 // Note: Also used by librustdoc, see PR #43348. Consider moving this struct elsewhere.
672 // FIXME: Currently the `everybody_loops` transformation is not applied to:
673 // * `const fn`, due to issue #43636 that `loop` is not supported for const evaluation. We are
674 // waiting for miri to fix that.
675 // * `impl Trait`, due to issue #43869 that functions returning impl Trait cannot be diverging.
676 // Solving this may require `!` to implement every trait, which relies on the an even more
677 // ambitious form of the closed RFC #1637. See also [#34511].
679 // [#34511]: https://github.com/rust-lang/rust/issues/34511#issuecomment-322340401
680 pub struct ReplaceBodyWithLoop<'a> {
681 within_static_or_const: bool,
682 nested_blocks: Option<Vec<ast::Block>>,
686 impl<'a> ReplaceBodyWithLoop<'a> {
687 pub fn new(sess: &'a Session) -> ReplaceBodyWithLoop<'a> {
688 ReplaceBodyWithLoop {
689 within_static_or_const: false,
695 fn run<R, F: FnOnce(&mut Self) -> R>(&mut self, is_const: bool, action: F) -> R {
696 let old_const = mem::replace(&mut self.within_static_or_const, is_const);
697 let old_blocks = self.nested_blocks.take();
698 let ret = action(self);
699 self.within_static_or_const = old_const;
700 self.nested_blocks = old_blocks;
704 fn should_ignore_fn(ret_ty: &ast::FnDecl) -> bool {
705 if let ast::FunctionRetTy::Ty(ref ty) = ret_ty.output {
706 fn involves_impl_trait(ty: &ast::Ty) -> bool {
708 ast::TyKind::ImplTrait(..) => true,
709 ast::TyKind::Slice(ref subty) |
710 ast::TyKind::Array(ref subty, _) |
711 ast::TyKind::Ptr(ast::MutTy { ty: ref subty, .. }) |
712 ast::TyKind::Rptr(_, ast::MutTy { ty: ref subty, .. }) |
713 ast::TyKind::Paren(ref subty) => involves_impl_trait(subty),
714 ast::TyKind::Tup(ref tys) => any_involves_impl_trait(tys.iter()),
715 ast::TyKind::Path(_, ref path) => path.segments.iter().any(|seg| {
716 match seg.args.as_ref().map(|generic_arg| &**generic_arg) {
718 Some(&ast::GenericArgs::AngleBracketed(ref data)) => {
719 let types = data.args.iter().filter_map(|arg| match arg {
720 ast::GenericArg::Type(ty) => Some(ty),
723 any_involves_impl_trait(types.into_iter()) ||
724 data.constraints.iter().any(|c| {
726 ast::AssocTyConstraintKind::Bound { .. } => true,
727 ast::AssocTyConstraintKind::Equality { ref ty } =>
728 involves_impl_trait(ty),
732 Some(&ast::GenericArgs::Parenthesized(ref data)) => {
733 any_involves_impl_trait(data.inputs.iter()) ||
734 any_involves_impl_trait(data.output.iter())
742 fn any_involves_impl_trait<'a, I: Iterator<Item = &'a P<ast::Ty>>>(mut it: I) -> bool {
743 it.any(|subty| involves_impl_trait(subty))
746 involves_impl_trait(ty)
753 impl<'a> MutVisitor for ReplaceBodyWithLoop<'a> {
754 fn visit_item_kind(&mut self, i: &mut ast::ItemKind) {
755 let is_const = match i {
756 ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => true,
757 ast::ItemKind::Fn(ref decl, ref header, _, _) =>
758 header.constness.node == ast::Constness::Const || Self::should_ignore_fn(decl),
761 self.run(is_const, |s| noop_visit_item_kind(i, s))
764 fn flat_map_trait_item(&mut self, i: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
765 let is_const = match i.node {
766 ast::TraitItemKind::Const(..) => true,
767 ast::TraitItemKind::Method(ast::MethodSig { ref decl, ref header, .. }, _) =>
768 header.constness.node == ast::Constness::Const || Self::should_ignore_fn(decl),
771 self.run(is_const, |s| noop_flat_map_trait_item(i, s))
774 fn flat_map_impl_item(&mut self, i: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
775 let is_const = match i.node {
776 ast::ImplItemKind::Const(..) => true,
777 ast::ImplItemKind::Method(ast::MethodSig { ref decl, ref header, .. }, _) =>
778 header.constness.node == ast::Constness::Const || Self::should_ignore_fn(decl),
781 self.run(is_const, |s| noop_flat_map_impl_item(i, s))
784 fn visit_anon_const(&mut self, c: &mut ast::AnonConst) {
785 self.run(true, |s| noop_visit_anon_const(c, s))
788 fn visit_block(&mut self, b: &mut P<ast::Block>) {
789 fn stmt_to_block(rules: ast::BlockCheckMode,
790 s: Option<ast::Stmt>,
791 sess: &Session) -> ast::Block {
793 stmts: s.into_iter().collect(),
795 id: sess.next_node_id(),
796 span: syntax_pos::DUMMY_SP,
800 fn block_to_stmt(b: ast::Block, sess: &Session) -> ast::Stmt {
801 let expr = P(ast::Expr {
802 id: sess.next_node_id(),
803 node: ast::ExprKind::Block(P(b), None),
804 span: syntax_pos::DUMMY_SP,
805 attrs: ThinVec::new(),
809 id: sess.next_node_id(),
810 node: ast::StmtKind::Expr(expr),
811 span: syntax_pos::DUMMY_SP,
815 let empty_block = stmt_to_block(BlockCheckMode::Default, None, self.sess);
816 let loop_expr = P(ast::Expr {
817 node: ast::ExprKind::Loop(P(empty_block), None),
818 id: self.sess.next_node_id(),
819 span: syntax_pos::DUMMY_SP,
820 attrs: ThinVec::new(),
823 let loop_stmt = ast::Stmt {
824 id: self.sess.next_node_id(),
825 span: syntax_pos::DUMMY_SP,
826 node: ast::StmtKind::Expr(loop_expr),
829 if self.within_static_or_const {
830 noop_visit_block(b, self)
832 visit_clobber(b.deref_mut(), |b| {
833 let mut stmts = vec![];
835 let old_blocks = self.nested_blocks.replace(vec![]);
837 stmts.extend(self.flat_map_stmt(s).into_iter().filter(|s| s.is_item()));
839 // we put a Some in there earlier with that replace(), so this is valid
840 let new_blocks = self.nested_blocks.take().unwrap();
841 self.nested_blocks = old_blocks;
842 stmts.extend(new_blocks.into_iter().map(|b| block_to_stmt(b, &self.sess)));
845 let mut new_block = ast::Block {
850 if let Some(old_blocks) = self.nested_blocks.as_mut() {
851 //push our fresh block onto the cache and yield an empty block with `loop {}`
852 if !new_block.stmts.is_empty() {
853 old_blocks.push(new_block);
856 stmt_to_block(b.rules, Some(loop_stmt), self.sess)
858 //push `loop {}` onto the end of our fresh block and yield that
859 new_block.stmts.push(loop_stmt);
867 // in general the pretty printer processes unexpanded code, so
868 // we override the default `visit_mac` method which panics.
869 fn visit_mac(&mut self, mac: &mut ast::Mac) {
870 noop_visit_mac(mac, self)