Rollup of 9 pull requests

src/bootstrap/native.rs

@@ -262,7 +262,7 @@ impl Step for Llvm {
             cfg.define("PYTHON_EXECUTABLE", python);
         }
 
-        configure_cmake(builder, target, &mut cfg);
+        configure_cmake(builder, target, &mut cfg, true);
 
         // FIXME: we don't actually need to build all LLVM tools and all LLVM
         //        libraries here, e.g., we just want a few components and a few
@@ -301,7 +301,12 @@ fn check_llvm_version(builder: &Builder<'_>, llvm_config: &Path) {
     panic!("\n\nbad LLVM version: {}, need >=7.0\n\n", version)
 }
 
-fn configure_cmake(builder: &Builder<'_>, target: Interned<String>, cfg: &mut cmake::Config) {
+fn configure_cmake(
+    builder: &Builder<'_>,
+    target: Interned<String>,
+    cfg: &mut cmake::Config,
+    use_compiler_launcher: bool,
+) {
     // Do not print installation messages for up-to-date files.
     // LLVM and LLD builds can produce a lot of those and hit CI limits on log size.
     cfg.define("CMAKE_INSTALL_MESSAGE", "LAZY");
@@ -372,9 +377,11 @@ fn configure_cmake(builder: &Builder<'_>, target: Interned<String>, cfg: &mut cm
     } else {
         // If ccache is configured we inform the build a little differently how
         // to invoke ccache while also invoking our compilers.
-        if let Some(ref ccache) = builder.config.ccache {
-            cfg.define("CMAKE_C_COMPILER_LAUNCHER", ccache)
-                .define("CMAKE_CXX_COMPILER_LAUNCHER", ccache);
+        if use_compiler_launcher {
+            if let Some(ref ccache) = builder.config.ccache {
+                cfg.define("CMAKE_C_COMPILER_LAUNCHER", ccache)
+                    .define("CMAKE_CXX_COMPILER_LAUNCHER", ccache);
+            }
         }
         cfg.define("CMAKE_C_COMPILER", sanitize_cc(cc))
             .define("CMAKE_CXX_COMPILER", sanitize_cc(cxx));
@@ -458,7 +465,7 @@ impl Step for Lld {
         t!(fs::create_dir_all(&out_dir));
 
         let mut cfg = cmake::Config::new(builder.src.join("src/llvm-project/lld"));
-        configure_cmake(builder, target, &mut cfg);
+        configure_cmake(builder, target, &mut cfg, true);
 
         // This is an awful, awful hack. Discovered when we migrated to using
         // clang-cl to compile LLVM/LLD it turns out that LLD, when built out of
@@ -595,10 +602,7 @@ impl Step for Sanitizers {
         let _time = util::timeit(&builder);
 
         let mut cfg = cmake::Config::new(&compiler_rt_dir);
-        cfg.target(&self.target);
-        cfg.host(&builder.config.build);
         cfg.profile("Release");
-
         cfg.define("CMAKE_C_COMPILER_TARGET", self.target);
         cfg.define("COMPILER_RT_BUILD_BUILTINS", "OFF");
         cfg.define("COMPILER_RT_BUILD_CRT", "OFF");
@@ -610,6 +614,12 @@ impl Step for Sanitizers {
         cfg.define("COMPILER_RT_USE_LIBCXX", "OFF");
         cfg.define("LLVM_CONFIG_PATH", &llvm_config);
 
+        // On Darwin targets the sanitizer runtimes are build as universal binaries.
+        // Unfortunately sccache currently lacks support to build them successfully.
+        // Disable compiler launcher on Darwin targets to avoid potential issues.
+        let use_compiler_launcher = !self.target.contains("apple-darwin");
+        configure_cmake(builder, self.target, &mut cfg, use_compiler_launcher);
+
         t!(fs::create_dir_all(&out_dir));
         cfg.out_dir(out_dir);
 

src/libcore/marker.rs

@@ -727,6 +727,10 @@ unsafe impl<T: ?Sized> Freeze for &mut T {}
 /// [`Pin<P>`]: ../pin/struct.Pin.html
 /// [`pin module`]: ../../std/pin/index.html
 #[stable(feature = "pin", since = "1.33.0")]
+#[rustc_on_unimplemented(
+    on(_Self = "std::future::Future", note = "consider using `Box::pin`",),
+    message = "`{Self}` cannot be unpinned"
+)]
 #[lang = "unpin"]
 pub auto trait Unpin {}
 

src/librustc/traits/error_reporting/on_unimplemented.rs

@@ -201,6 +201,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 }
             }
         }
+        if let ty::Dynamic(traits, _) = self_ty.kind {
+            for t in *traits.skip_binder() {
+                match t {
+                    ty::ExistentialPredicate::Trait(trait_ref) => {
+                        flags.push((sym::_Self, Some(self.tcx.def_path_str(trait_ref.def_id))))
+                    }
+                    _ => {}
+                }
+            }
+        }
 
         if let Ok(Some(command)) =
             OnUnimplementedDirective::of_item(self.tcx, trait_ref.def_id, def_id)

src/librustc/traits/error_reporting/suggestions.rs

@@ -701,10 +701,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     })
                     .collect::<Vec<_>>();
                 // Add the suggestion for the return type.
-                suggestions.push((
-                    ret_ty.span,
-                    format!("Box<{}{}>", if has_dyn { "" } else { "dyn " }, snippet),
-                ));
+                suggestions.push((ret_ty.span, format!("Box<dyn {}>", trait_obj)));
                 err.multipart_suggestion(
                     "return a boxed trait object instead",
                     suggestions,

src/librustc_expand/lib.rs

@@ -1,3 +1,4 @@
+#![feature(cow_is_borrowed)]
 #![feature(crate_visibility_modifier)]
 #![feature(decl_macro)]
 #![feature(proc_macro_diagnostic)]

src/librustc_expand/mbe/macro_parser.rs

@@ -78,20 +78,19 @@ use crate::mbe::{self, TokenTree};
 
 use rustc_ast_pretty::pprust;
 use rustc_parse::parser::{FollowedByType, Parser, PathStyle};
-use rustc_parse::Directory;
 use rustc_session::parse::ParseSess;
 use rustc_span::symbol::{kw, sym, Symbol};
 use syntax::ast::{Ident, Name};
 use syntax::ptr::P;
 use syntax::token::{self, DocComment, Nonterminal, Token};
-use syntax::tokenstream::TokenStream;
 
 use rustc_errors::{FatalError, PResult};
 use rustc_span::Span;
 use smallvec::{smallvec, SmallVec};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
+use std::borrow::Cow;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::mem;
 use std::ops::{Deref, DerefMut};
@@ -613,28 +612,9 @@ fn inner_parse_loop<'root, 'tt>(
     Success(())
 }
 
-/// Use the given sequence of token trees (`ms`) as a matcher. Match the given token stream `tts`
-/// against it and return the match.
-///
-/// # Parameters
-///
-/// - `sess`: The session into which errors are emitted
-/// - `tts`: The tokenstream we are matching against the pattern `ms`
-/// - `ms`: A sequence of token trees representing a pattern against which we are matching
-/// - `directory`: Information about the file locations (needed for the black-box parser)
-/// - `recurse_into_modules`: Whether or not to recurse into modules (needed for the black-box
-///   parser)
-pub(super) fn parse(
-    sess: &ParseSess,
-    tts: TokenStream,
-    ms: &[TokenTree],
-    directory: Option<Directory<'_>>,
-    recurse_into_modules: bool,
-) -> NamedParseResult {
-    // Create a parser that can be used for the "black box" parts.
-    let mut parser =
-        Parser::new(sess, tts, directory, recurse_into_modules, true, rustc_parse::MACRO_ARGUMENTS);
-
+/// Use the given sequence of token trees (`ms`) as a matcher. Match the token
+/// stream from the given `parser` against it and return the match.
+pub(super) fn parse_tt(parser: &mut Cow<'_, Parser<'_>>, ms: &[TokenTree]) -> NamedParseResult {
     // A queue of possible matcher positions. We initialize it with the matcher position in which
     // the "dot" is before the first token of the first token tree in `ms`. `inner_parse_loop` then
     // processes all of these possible matcher positions and produces possible next positions into
@@ -659,7 +639,7 @@ pub(super) fn parse(
         // parsing from the black-box parser done. The result is that `next_items` will contain a
         // bunch of possible next matcher positions in `next_items`.
         match inner_parse_loop(
-            sess,
+            parser.sess,
             &mut cur_items,
             &mut next_items,
             &mut eof_items,
@@ -684,7 +664,7 @@ pub(super) fn parse(
             if eof_items.len() == 1 {
                 let matches =
                     eof_items[0].matches.iter_mut().map(|dv| Lrc::make_mut(dv).pop().unwrap());
-                return nameize(sess, ms, matches);
+                return nameize(parser.sess, ms, matches);
             } else if eof_items.len() > 1 {
                 return Error(
                     parser.token.span,
@@ -709,9 +689,14 @@ pub(super) fn parse(
         // unnecessary implicit clone later in Rc::make_mut.
         drop(eof_items);
 
+        // If there are no possible next positions AND we aren't waiting for the black-box parser,
+        // then there is a syntax error.
+        if bb_items.is_empty() && next_items.is_empty() {
+            return Failure(parser.token.clone(), "no rules expected this token in macro call");
+        }
         // Another possibility is that we need to call out to parse some rust nonterminal
         // (black-box) parser. However, if there is not EXACTLY ONE of these, something is wrong.
-        if (!bb_items.is_empty() && !next_items.is_empty()) || bb_items.len() > 1 {
+        else if (!bb_items.is_empty() && !next_items.is_empty()) || bb_items.len() > 1 {
             let nts = bb_items
                 .iter()
                 .map(|item| match item.top_elts.get_tt(item.idx) {
@@ -733,16 +718,11 @@ pub(super) fn parse(
                 ),
             );
         }
-        // If there are no possible next positions AND we aren't waiting for the black-box parser,
-        // then there is a syntax error.
-        else if bb_items.is_empty() && next_items.is_empty() {
-            return Failure(parser.token.take(), "no rules expected this token in macro call");
-        }
         // Dump all possible `next_items` into `cur_items` for the next iteration.
         else if !next_items.is_empty() {
             // Now process the next token
             cur_items.extend(next_items.drain(..));
-            parser.bump();
+            parser.to_mut().bump();
         }
         // Finally, we have the case where we need to call the black-box parser to get some
         // nonterminal.
@@ -754,7 +734,7 @@ pub(super) fn parse(
                 let match_cur = item.match_cur;
                 item.push_match(
                     match_cur,
-                    MatchedNonterminal(Lrc::new(parse_nt(&mut parser, span, ident.name))),
+                    MatchedNonterminal(Lrc::new(parse_nt(parser.to_mut(), span, ident.name))),
                 );
                 item.idx += 1;
                 item.match_cur += 1;

src/librustc_expand/mbe/macro_rules.rs

@@ -1,11 +1,11 @@
-use crate::base::{DummyResult, ExtCtxt, MacResult, TTMacroExpander};
+use crate::base::{DummyResult, ExpansionData, ExtCtxt, MacResult, TTMacroExpander};
 use crate::base::{SyntaxExtension, SyntaxExtensionKind};
 use crate::expand::{ensure_complete_parse, parse_ast_fragment, AstFragment, AstFragmentKind};
 use crate::mbe;
 use crate::mbe::macro_check;
-use crate::mbe::macro_parser::parse;
+use crate::mbe::macro_parser::parse_tt;
 use crate::mbe::macro_parser::{Error, Failure, Success};
-use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedParseResult};
+use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq};
 use crate::mbe::transcribe::transcribe;
 
 use rustc_ast_pretty::pprust;
@@ -166,9 +166,9 @@ impl TTMacroExpander for MacroRulesMacroExpander {
     }
 }
 
-fn trace_macros_note(cx: &mut ExtCtxt<'_>, sp: Span, message: String) {
+fn trace_macros_note(cx_expansions: &mut FxHashMap<Span, Vec<String>>, sp: Span, message: String) {
     let sp = sp.macro_backtrace().last().map(|trace| trace.call_site).unwrap_or(sp);
-    cx.expansions.entry(sp).or_default().push(message);
+    cx_expansions.entry(sp).or_default().push(message);
 }
 
 /// Given `lhses` and `rhses`, this is the new macro we create
@@ -184,12 +184,36 @@ fn generic_extension<'cx>(
 ) -> Box<dyn MacResult + 'cx> {
     if cx.trace_macros() {
         let msg = format!("expanding `{}! {{ {} }}`", name, pprust::tts_to_string(arg.clone()));
-        trace_macros_note(cx, sp, msg);
+        trace_macros_note(&mut cx.expansions, sp, msg);
     }
 
     // Which arm's failure should we report? (the one furthest along)
     let mut best_failure: Option<(Token, &str)> = None;
+
+    // We create a base parser that can be used for the "black box" parts.
+    // Every iteration needs a fresh copy of that base parser. However, the
+    // parser is not mutated on many of the iterations, particularly when
+    // dealing with macros like this:
+    //
+    // macro_rules! foo {
+    //     ("a") => (A);
+    //     ("b") => (B);
+    //     ("c") => (C);
+    //     // ... etc. (maybe hundreds more)
+    // }
+    //
+    // as seen in the `html5ever` benchmark. We use a `Cow` so that the base
+    // parser is only cloned when necessary (upon mutation). Furthermore, we
+    // reinitialize the `Cow` with the base parser at the start of every
+    // iteration, so that any mutated parsers are not reused. This is all quite
+    // hacky, but speeds up the `html5ever` benchmark significantly. (Issue
+    // 68836 suggests a more comprehensive but more complex change to deal with
+    // this situation.)
+    let base_parser = base_parser_from_cx(&cx.current_expansion, &cx.parse_sess, arg.clone());
+
     for (i, lhs) in lhses.iter().enumerate() {
+        let mut parser = Cow::Borrowed(&base_parser);
+
         // try each arm's matchers
         let lhs_tt = match *lhs {
             mbe::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
@@ -202,7 +226,7 @@ fn generic_extension<'cx>(
         // are not recorded. On the first `Success(..)`ful matcher, the spans are merged.
         let mut gated_spans_snaphot = mem::take(&mut *cx.parse_sess.gated_spans.spans.borrow_mut());
 
-        match parse_tt(cx, lhs_tt, arg.clone()) {
+        match parse_tt(&mut parser, lhs_tt) {
             Success(named_matches) => {
                 // The matcher was `Success(..)`ful.
                 // Merge the gated spans from parsing the matcher with the pre-existing ones.
@@ -232,11 +256,11 @@ fn generic_extension<'cx>(
 
                 if cx.trace_macros() {
                     let msg = format!("to `{}`", pprust::tts_to_string(tts.clone()));
-                    trace_macros_note(cx, sp, msg);
+                    trace_macros_note(&mut cx.expansions, sp, msg);
                 }
 
                 let directory = Directory {
-                    path: Cow::from(cx.current_expansion.module.directory.as_path()),
+                    path: cx.current_expansion.module.directory.clone(),
                     ownership: cx.current_expansion.directory_ownership,
                 };
                 let mut p = Parser::new(cx.parse_sess(), tts, Some(directory), true, false, None);
@@ -269,6 +293,7 @@ fn generic_extension<'cx>(
         // Restore to the state before snapshotting and maybe try again.
         mem::swap(&mut gated_spans_snaphot, &mut cx.parse_sess.gated_spans.spans.borrow_mut());
     }
+    drop(base_parser);
 
     let (token, label) = best_failure.expect("ran no matchers");
     let span = token.span.substitute_dummy(sp);
@@ -286,7 +311,9 @@ fn generic_extension<'cx>(
                 mbe::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
                 _ => continue,
             };
-            match parse_tt(cx, lhs_tt, arg.clone()) {
+            let base_parser =
+                base_parser_from_cx(&cx.current_expansion, &cx.parse_sess, arg.clone());
+            match parse_tt(&mut Cow::Borrowed(&base_parser), lhs_tt) {
                 Success(_) => {
                     if comma_span.is_dummy() {
                         err.note("you might be missing a comma");
@@ -368,7 +395,8 @@ pub fn compile_declarative_macro(
         ),
     ];
 
-    let argument_map = match parse(sess, body, &argument_gram, None, true) {
+    let base_parser = Parser::new(sess, body, None, true, true, rustc_parse::MACRO_ARGUMENTS);
+    let argument_map = match parse_tt(&mut Cow::Borrowed(&base_parser), &argument_gram) {
         Success(m) => m,
         Failure(token, msg) => {
             let s = parse_failure_msg(&token);
@@ -1184,14 +1212,16 @@ fn quoted_tt_to_string(tt: &mbe::TokenTree) -> String {
     }
 }
 
-/// Use this token tree as a matcher to parse given tts.
-fn parse_tt(cx: &ExtCtxt<'_>, mtch: &[mbe::TokenTree], tts: TokenStream) -> NamedParseResult {
-    // `None` is because we're not interpolating
+fn base_parser_from_cx<'cx>(
+    current_expansion: &'cx ExpansionData,
+    sess: &'cx ParseSess,
+    tts: TokenStream,
+) -> Parser<'cx> {
     let directory = Directory {
-        path: Cow::from(cx.current_expansion.module.directory.as_path()),
-        ownership: cx.current_expansion.directory_ownership,
+        path: current_expansion.module.directory.clone(),
+        ownership: current_expansion.directory_ownership,
     };
-    parse(cx.parse_sess(), tts, mtch, Some(directory), true)
+    Parser::new(sess, tts, Some(directory), true, true, rustc_parse::MACRO_ARGUMENTS)
 }
 
 /// Generates an appropriate parsing failure message. For EOF, this is "unexpected end...". For