Rollup of 6 pull requests

compiler/rustc_codegen_ssa/src/base.rs

@@ -357,20 +357,9 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) {
             return None;
         }
-    } else {
-        // FIXME: Add support for non-local main fn codegen
-        let span = cx.tcx().main_def.unwrap().span;
-        let n = 28937;
-        cx.sess()
-            .struct_span_err(span, "entry symbol `main` from foreign crate is not yet supported.")
-            .note(&format!(
-                "see issue #{} <https://github.com/rust-lang/rust/issues/{}> \
-                 for more information",
-                n, n,
-            ))
-            .emit();
-        cx.sess().abort_if_errors();
-        bug!();
+    } else if !cx.codegen_unit().is_primary() {
+        // We want to create the wrapper only when the codegen unit is the primary one
+        return None;
     }
 
     let main_llfn = cx.get_fn_addr(instance);

compiler/rustc_feature/src/active.rs

@@ -274,9 +274,6 @@ declare_features! (
     /// Allows using non lexical lifetimes (RFC 2094).
     (active, nll, "1.0.0", Some(43234), None),
 
-    /// Allows the definition of `const` functions with some advanced features.
-    (active, const_fn, "1.2.0", Some(57563), None),
-
     /// Allows associated type defaults.
     (active, associated_type_defaults, "1.2.0", Some(29661), None),
 

compiler/rustc_feature/src/removed.rs

@@ -136,6 +136,9 @@ declare_features! (
     (removed, main, "1.53.0", Some(29634), None, None),
     (removed, pub_macro_rules, "1.53.0", Some(78855), None,
      Some("removed due to being incomplete, in particular it does not work across crates")),
+     /// Allows the definition of `const` functions with some advanced features.
+    (removed, const_fn, "1.54.0", Some(57563), None,
+     Some("split into finer-grained feature gates")),
 
     // -------------------------------------------------------------------------
     // feature-group-end: removed features

compiler/rustc_lint/src/non_fmt_panic.rs

@@ -4,7 +4,7 @@ use rustc_errors::{pluralize, Applicability};
 use rustc_hir as hir;
 use rustc_middle::ty;
 use rustc_parse_format::{ParseMode, Parser, Piece};
-use rustc_span::{sym, symbol::kw, InnerSpan, Span, Symbol};
+use rustc_span::{hygiene, sym, symbol::kw, symbol::SymbolStr, InnerSpan, Span, Symbol};
 
 declare_lint! {
     /// The `non_fmt_panic` lint detects `panic!(..)` invocations where the first
@@ -67,7 +67,7 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
 
     // The argument is *not* a string literal.
 
-    let (span, panic) = panic_call(cx, f);
+    let (span, panic, symbol_str) = panic_call(cx, f);
 
     // Find the span of the argument to `panic!()`, before expansion in the
     // case of `panic!(some_macro!())`.
@@ -95,7 +95,7 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
         }
         if arg_macro.map_or(false, |id| cx.tcx.is_diagnostic_item(sym::format_macro, id)) {
             // A case of `panic!(format!(..))`.
-            l.note("the panic!() macro supports formatting, so there's no need for the format!() macro here");
+            l.note(format!("the {}!() macro supports formatting, so there's no need for the format!() macro here", symbol_str).as_str());
             if let Some((open, close, _)) = find_delimiters(cx, arg_span) {
                 l.multipart_suggestion(
                     "remove the `format!(..)` macro call",
@@ -160,7 +160,7 @@ fn check_panic_str<'tcx>(
         Parser::new(fmt.as_ref(), style, snippet.clone(), false, ParseMode::Format);
     let n_arguments = (&mut fmt_parser).filter(|a| matches!(a, Piece::NextArgument(_))).count();
 
-    let (span, _) = panic_call(cx, f);
+    let (span, _, _) = panic_call(cx, f);
 
     if n_arguments > 0 && fmt_parser.errors.is_empty() {
         let arg_spans: Vec<_> = match &fmt_parser.arg_places[..] {
@@ -230,7 +230,7 @@ fn find_delimiters<'tcx>(cx: &LateContext<'tcx>, span: Span) -> Option<(Span, Sp
     ))
 }
 
-fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span, Symbol) {
+fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span, Symbol, SymbolStr) {
     let mut expn = f.span.ctxt().outer_expn_data();
 
     let mut panic_macro = kw::Empty;
@@ -248,5 +248,10 @@ fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span,
         }
     }
 
-    (expn.call_site, panic_macro)
+    let macro_symbol = if let hygiene::ExpnKind::Macro(_, symbol) = expn.kind {
+        symbol
+    } else {
+        Symbol::intern("panic")
+    };
+    (expn.call_site, panic_macro, macro_symbol.as_str())
 }

compiler/rustc_middle/src/mir/mono.rs

@@ -229,6 +229,7 @@ pub struct CodegenUnit<'tcx> {
     name: Symbol,
     items: FxHashMap<MonoItem<'tcx>, (Linkage, Visibility)>,
     size_estimate: Option<usize>,
+    primary: bool,
 }
 
 /// Specifies the linkage type for a `MonoItem`.
@@ -258,7 +259,7 @@ pub enum Visibility {
 
 impl<'tcx> CodegenUnit<'tcx> {
     pub fn new(name: Symbol) -> CodegenUnit<'tcx> {
-        CodegenUnit { name, items: Default::default(), size_estimate: None }
+        CodegenUnit { name, items: Default::default(), size_estimate: None, primary: false }
     }
 
     pub fn name(&self) -> Symbol {
@@ -269,6 +270,14 @@ impl<'tcx> CodegenUnit<'tcx> {
         self.name = name;
     }
 
+    pub fn is_primary(&self) -> bool {
+        self.primary
+    }
+
+    pub fn make_primary(&mut self) {
+        self.primary = true;
+    }
+
     pub fn items(&self) -> &FxHashMap<MonoItem<'tcx>, (Linkage, Visibility)> {
         &self.items
     }
@@ -378,6 +387,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for CodegenUnit<'tcx> {
             name,
             // The size estimate is not relevant to the hash
             size_estimate: _,
+            primary: _,
         } = *self;
 
         name.hash_stable(hcx, hasher);

compiler/rustc_mir/src/monomorphize/partitioning/mod.rs

@@ -350,12 +350,14 @@ fn collect_and_partition_mono_items<'tcx>(
     let (codegen_units, _) = tcx.sess.time("partition_and_assert_distinct_symbols", || {
         sync::join(
             || {
-                &*tcx.arena.alloc_from_iter(partition(
+                let mut codegen_units = partition(
                     tcx,
                     &mut items.iter().cloned(),
                     tcx.sess.codegen_units(),
                     &inlining_map,
-                ))
+                );
+                codegen_units[0].make_primary();
+                &*tcx.arena.alloc_from_iter(codegen_units)
             },
             || assert_symbols_are_distinct(tcx, items.iter()),
         )

compiler/rustc_parse/src/parser/mod.rs

@@ -1077,7 +1077,7 @@ impl<'a> Parser<'a> {
                     let span = expr.span;
 
                     match &expr.kind {
-                        // Not gated to supporte things like `doc = $expr` that work on stable.
+                        // Not gated to support things like `doc = $expr` that work on stable.
                         _ if is_interpolated_expr => {}
                         ExprKind::Lit(lit) if lit.kind.is_unsuffixed() => {}
                         _ => self.sess.gated_spans.gate(sym::extended_key_value_attributes, span),

compiler/rustc_session/src/config.rs

@@ -893,8 +893,13 @@ pub fn build_configuration(sess: &Session, mut user_cfg: CrateConfig) -> CrateCo
     user_cfg
 }
 
-pub(super) fn build_target_config(opts: &Options, target_override: Option<Target>) -> Target {
-    let target_result = target_override.map_or_else(|| Target::search(&opts.target_triple), Ok);
+pub(super) fn build_target_config(
+    opts: &Options,
+    target_override: Option<Target>,
+    sysroot: &PathBuf,
+) -> Target {
+    let target_result =
+        target_override.map_or_else(|| Target::search(&opts.target_triple, sysroot), Ok);
     let target = target_result.unwrap_or_else(|e| {
         early_error(
             opts.error_format,

compiler/rustc_session/src/session.rs

@@ -1276,9 +1276,14 @@ pub fn build_session(
         DiagnosticOutput::Raw(write) => Some(write),
     };
 
-    let target_cfg = config::build_target_config(&sopts, target_override);
+    let sysroot = match &sopts.maybe_sysroot {
+        Some(sysroot) => sysroot.clone(),
+        None => filesearch::get_or_default_sysroot(),
+    };
+
+    let target_cfg = config::build_target_config(&sopts, target_override, &sysroot);
     let host_triple = TargetTriple::from_triple(config::host_triple());
-    let host = Target::search(&host_triple).unwrap_or_else(|e| {
+    let host = Target::search(&host_triple, &sysroot).unwrap_or_else(|e| {
         early_error(sopts.error_format, &format!("Error loading host specification: {}", e))
     });
 
@@ -1325,10 +1330,6 @@ pub fn build_session(
 
     let mut parse_sess = ParseSess::with_span_handler(span_diagnostic, source_map);
     parse_sess.assume_incomplete_release = sopts.debugging_opts.assume_incomplete_release;
-    let sysroot = match &sopts.maybe_sysroot {
-        Some(sysroot) => sysroot.clone(),
-        None => filesearch::get_or_default_sysroot(),
-    };
 
     let host_triple = config::host_triple();
     let target_triple = sopts.target_triple.triple();

compiler/rustc_target/src/spec/mod.rs

@@ -1898,13 +1898,15 @@ impl Target {
     }
 
     /// Search RUST_TARGET_PATH for a JSON file specifying the given target
-    /// triple. Note that it could also just be a bare filename already, so also
+    /// triple. If none is found, look for a file called `target.json` inside
+    /// the sysroot under the target-triple's `rustlib` directory.
+    /// Note that it could also just be a bare filename already, so also
     /// check for that. If one of the hardcoded targets we know about, just
     /// return it directly.
     ///
     /// The error string could come from any of the APIs called, including
     /// filesystem access and JSON decoding.
-    pub fn search(target_triple: &TargetTriple) -> Result<Target, String> {
+    pub fn search(target_triple: &TargetTriple, sysroot: &PathBuf) -> Result<Target, String> {
         use rustc_serialize::json;
         use std::env;
         use std::fs;
@@ -1931,14 +1933,21 @@ impl Target {
 
                 let target_path = env::var_os("RUST_TARGET_PATH").unwrap_or_default();
 
-                // FIXME 16351: add a sane default search path?
-
                 for dir in env::split_paths(&target_path) {
                     let p = dir.join(&path);
                     if p.is_file() {
                         return load_file(&p);
                     }
                 }
+
+                // Additionally look in the sysroot under `lib/rustlib/<triple>/target.json`
+                // as a fallback.
+                let p =
+                    sysroot.join("lib").join("rustlib").join(&target_triple).join("target.json");
+                if p.is_file() {
+                    return load_file(&p);
+                }
+
                 Err(format!("Could not find specification for target {:?}", target_triple))
             }
             TargetTriple::TargetPath(ref target_path) => {

library/std/src/lib.rs

@@ -246,7 +246,6 @@
 #![feature(const_cstr_unchecked)]
 #![feature(const_fn_floating_point_arithmetic)]
 #![feature(const_fn_transmute)]
-#![feature(const_fn)]
 #![feature(const_fn_fn_ptr_basics)]
 #![feature(const_io_structs)]
 #![feature(const_ip)]

src/librustdoc/clean/mod.rs

@@ -533,8 +533,7 @@ impl Clean<Generics> for hir::Generics<'_> {
                 match param.kind {
                     GenericParamDefKind::Lifetime => unreachable!(),
                     GenericParamDefKind::Type { did, ref bounds, .. } => {
-                        cx.impl_trait_bounds
-                            .insert(FakeDefId::new_real(did).into(), bounds.clone());
+                        cx.impl_trait_bounds.insert(did.into(), bounds.clone());
                     }
                     GenericParamDefKind::Const { .. } => unreachable!(),
                 }
@@ -615,7 +614,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
             .collect::<Vec<GenericParamDef>>();
 
         // param index -> [(DefId of trait, associated type name, type)]
-        let mut impl_trait_proj = FxHashMap::<u32, Vec<(FakeDefId, Symbol, Ty<'tcx>)>>::default();
+        let mut impl_trait_proj = FxHashMap::<u32, Vec<(DefId, Symbol, Ty<'tcx>)>>::default();
 
         let where_predicates = preds
             .predicates
@@ -687,13 +686,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
                 if let Some(proj) = impl_trait_proj.remove(&idx) {
                     for (trait_did, name, rhs) in proj {
                         let rhs = rhs.clean(cx);
-                        simplify::merge_bounds(
-                            cx,
-                            &mut bounds,
-                            trait_did.expect_real(),
-                            name,
-                            &rhs,
-                        );
+                        simplify::merge_bounds(cx, &mut bounds, trait_did, name, &rhs);
                     }
                 }
             } else {
@@ -1183,8 +1176,7 @@ fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
                 if let Some(new_ty) = cx.ty_substs.get(&did).cloned() {
                     return new_ty;
                 }
-                if let Some(bounds) = cx.impl_trait_bounds.remove(&FakeDefId::new_real(did).into())
-                {
+                if let Some(bounds) = cx.impl_trait_bounds.remove(&did.into()) {
                     return ImplTrait(bounds);
                 }
             }

src/librustdoc/clean/types.rs

@@ -73,10 +73,6 @@ impl FakeDefId {
         Self::Fake(DefIndex::from(id), krate)
     }
 
-    crate fn new_real(id: DefId) -> Self {
-        Self::Real(id)
-    }
-
     #[inline]
     crate fn is_local(self) -> bool {
         match self {
@@ -470,7 +466,7 @@ impl Item {
             .filter_map(|ItemLink { link: s, link_text, did, ref fragment }| {
                 match did {
                     Some(did) => {
-                        if let Some((mut href, ..)) = href(did.expect_real(), cx) {
+                        if let Some((mut href, ..)) = href(did.clone(), cx) {
                             if let Some(ref fragment) = *fragment {
                                 href.push('#');
                                 href.push_str(fragment);
@@ -972,7 +968,7 @@ crate struct ItemLink {
     /// This may not be the same as `link` if there was a disambiguator
     /// in an intra-doc link (e.g. \[`fn@f`\])
     pub(crate) link_text: String,
-    pub(crate) did: Option<FakeDefId>,
+    pub(crate) did: Option<DefId>,
     /// The url fragment to append to the link
     pub(crate) fragment: Option<String>,
 }

src/librustdoc/core.rs

@@ -576,12 +576,12 @@ impl<'tcx> Visitor<'tcx> for EmitIgnoredResolutionErrors<'tcx> {
 /// for `impl Trait` in argument position.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 crate enum ImplTraitParam {
-    DefId(FakeDefId),
+    DefId(DefId),
     ParamIndex(u32),
 }
 
-impl From<FakeDefId> for ImplTraitParam {
-    fn from(did: FakeDefId) -> Self {
+impl From<DefId> for ImplTraitParam {
+    fn from(did: DefId) -> Self {
         ImplTraitParam::DefId(did)
     }
 }

src/librustdoc/formats/cache.rs

@@ -67,7 +67,7 @@ crate struct Cache {
     /// When rendering traits, it's often useful to be able to list all
     /// implementors of the trait, and this mapping is exactly, that: a mapping
     /// of trait ids to the list of known implementors of the trait
-    crate implementors: FxHashMap<FakeDefId, Vec<Impl>>,
+    crate implementors: FxHashMap<DefId, Vec<Impl>>,
 
     /// Cache of where external crate documentation can be found.
     crate extern_locations: FxHashMap<CrateNum, ExternalLocation>,
@@ -299,7 +299,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                             desc: item
                                 .doc_value()
                                 .map_or_else(String::new, |x| short_markdown_summary(&x.as_str())),
-                            parent: parent.map(FakeDefId::new_real),
+                            parent,
                             parent_idx: None,
                             search_type: get_index_search_type(&item, &self.empty_cache, self.tcx),
                             aliases: item.attrs.get_doc_aliases(),