Rollup of 8 pull requests

Cargo.lock

@@ -356,7 +356,7 @@ dependencies = [
 
 [[package]]
 name = "cargo-platform"
-version = "0.1.1"
+version = "0.1.2"
 dependencies = [
  "serde",
 ]
@@ -1723,9 +1723,9 @@ checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
 [[package]]
 name = "jobserver"
-version = "0.1.22"
+version = "0.1.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "972f5ae5d1cb9c6ae417789196c803205313edde988685da5e3aae0827b9e7fd"
+checksum = "f5ca711fd837261e14ec9e674f092cbb931d3fa1482b017ae59328ddc6f3212b"
 dependencies = [
  "libc",
 ]

compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs

@@ -1136,6 +1136,11 @@ pub(crate) fn codegen_intrinsic_call<'tcx>(
                 };
             ret.write_cvalue(fx, CValue::by_val(is_eq_value, ret.layout()));
         };
+
+        black_box, (c a) {
+            // FIXME implement black_box semantics
+            ret.write_cvalue(fx, a);
+        };
     }
 
     if let Some((_, dest)) = destination {

compiler/rustc_codegen_llvm/src/asm.rs

@@ -425,7 +425,7 @@ impl AsmMethods for CodegenCx<'ll, 'tcx> {
     }
 }
 
-fn inline_asm_call(
+pub(crate) fn inline_asm_call(
     bx: &mut Builder<'a, 'll, 'tcx>,
     asm: &str,
     cons: &str,

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -7,6 +7,7 @@ use crate::type_of::LayoutLlvmExt;
 use crate::va_arg::emit_va_arg;
 use crate::value::Value;
 
+use rustc_ast as ast;
 use rustc_codegen_ssa::base::{compare_simd_types, wants_msvc_seh};
 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
@@ -327,6 +328,31 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
                 }
             }
 
+            sym::black_box => {
+                args[0].val.store(self, result);
+
+                // We need to "use" the argument in some way LLVM can't introspect, and on
+                // targets that support it we can typically leverage inline assembly to do
+                // this. LLVM's interpretation of inline assembly is that it's, well, a black
+                // box. This isn't the greatest implementation since it probably deoptimizes
+                // more than we want, but it's so far good enough.
+                crate::asm::inline_asm_call(
+                    self,
+                    "",
+                    "r,~{memory}",
+                    &[result.llval],
+                    self.type_void(),
+                    true,
+                    false,
+                    ast::LlvmAsmDialect::Att,
+                    &[span],
+                )
+                .unwrap_or_else(|| bug!("failed to generate inline asm call for `black_box`"));
+
+                // We have copied the value to `result` already.
+                return;
+            }
+
             _ if name_str.starts_with("simd_") => {
                 match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
                     Ok(llval) => llval,

compiler/rustc_driver/src/lib.rs

@@ -1287,9 +1287,6 @@ pub fn init_env_logger(env: &str) {
         .with_indent_lines(true)
         .with_ansi(color_logs)
         .with_targets(true)
-        .with_wraparound(10)
-        .with_verbose_exit(true)
-        .with_verbose_entry(true)
         .with_indent_amount(2);
     #[cfg(parallel_compiler)]
     let layer = layer.with_thread_ids(true).with_thread_names(true);

compiler/rustc_lexer/src/unescape.rs

@@ -60,13 +60,17 @@ pub enum EscapeError {
     /// After a line ending with '\', the next line contains whitespace
     /// characters that are not skipped.
     UnskippedWhitespaceWarning,
+
+    /// After a line ending with '\', multiple lines are skipped.
+    MultipleSkippedLinesWarning,
 }
 
 impl EscapeError {
     /// Returns true for actual errors, as opposed to warnings.
     pub fn is_fatal(&self) -> bool {
         match self {
             EscapeError::UnskippedWhitespaceWarning => false,
+            EscapeError::MultipleSkippedLinesWarning => false,
             _ => true,
         }
     }
@@ -315,12 +319,17 @@ where
     where
         F: FnMut(Range<usize>, Result<char, EscapeError>),
     {
-        let str = chars.as_str();
-        let first_non_space = str
+        let tail = chars.as_str();
+        let first_non_space = tail
             .bytes()
             .position(|b| b != b' ' && b != b'\t' && b != b'\n' && b != b'\r')
-            .unwrap_or(str.len());
-        let tail = &str[first_non_space..];
+            .unwrap_or(tail.len());
+        if tail[1..first_non_space].contains('\n') {
+            // The +1 accounts for the escaping slash.
+            let end = start + first_non_space + 1;
+            callback(start..end, Err(EscapeError::MultipleSkippedLinesWarning));
+        }
+        let tail = &tail[first_non_space..];
         if let Some(c) = tail.chars().nth(0) {
             // For error reporting, we would like the span to contain the character that was not
             // skipped.  The +1 is necessary to account for the leading \ that started the escape.

compiler/rustc_lexer/src/unescape/tests.rs

@@ -106,6 +106,10 @@ fn test_unescape_str_warn() {
         assert_eq!(unescaped, expected);
     }
 
+    // Check we can handle escaped newlines at the end of a file.
+    check("\\\n", &[]);
+    check("\\\n ", &[]);
+
     check(
         "\\\n \u{a0} x",
         &[
@@ -115,6 +119,7 @@ fn test_unescape_str_warn() {
             (6..7, Ok('x')),
         ],
     );
+    check("\\\n  \n  x", &[(0..7, Err(EscapeError::MultipleSkippedLinesWarning)), (7..8, Ok('x'))]);
 }
 
 #[test]

compiler/rustc_lint/src/array_into_iter.rs

@@ -32,7 +32,7 @@ declare_lint! {
     Warn,
     "detects calling `into_iter` on arrays in Rust 2015 and 2018",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #66145 <https://github.com/rust-lang/rust/issues/66145>",
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/IntoIterator-for-arrays.html>",
         reason: FutureIncompatibilityReason::EditionSemanticsChange(Edition::Edition2021),
     };
 }

compiler/rustc_lint/src/builtin.rs

@@ -1680,7 +1680,7 @@ declare_lint! {
     Warn,
     "`...` range patterns are deprecated",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #80165 <https://github.com/rust-lang/rust/issues/80165>",
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>",
         reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021),
     };
 }

compiler/rustc_lint_defs/src/builtin.rs

@@ -1605,7 +1605,7 @@ declare_lint! {
     Warn,
     "suggest using `dyn Trait` for trait objects",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #80165 <https://github.com/rust-lang/rust/issues/80165>",
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>",
         reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021),
     };
 }
@@ -3247,7 +3247,7 @@ declare_lint! {
     Allow,
     "detects usage of old versions of or-patterns",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #84869 <https://github.com/rust-lang/rust/issues/84869>",
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/or-patterns-macro-rules.html>",
         reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021),
     };
 }
@@ -3296,7 +3296,7 @@ declare_lint! {
     "detects the usage of trait methods which are ambiguous with traits added to the \
         prelude in future editions",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #85684 <https://github.com/rust-lang/rust/issues/85684>",
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/prelude.html>",
         reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021),
     };
 }
@@ -3331,7 +3331,7 @@ declare_lint! {
     Allow,
     "identifiers that will be parsed as a prefix in Rust 2021",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #84978 <https://github.com/rust-lang/rust/issues/84978>",
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/reserving-syntax.html>",
         reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021),
     };
     crate_level_only

compiler/rustc_mir/src/interpret/intrinsics.rs

@@ -465,7 +465,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 );
                 self.copy_op(&self.operand_index(&args[0], index)?, dest)?;
             }
-            sym::likely | sym::unlikely => {
+            sym::likely | sym::unlikely | sym::black_box => {
                 // These just return their argument
                 self.copy_op(&args[0], dest)?;
             }

compiler/rustc_parse/src/lexer/unescape_error_reporting.rs

@@ -280,6 +280,11 @@ pub(crate) fn emit_unescape_error(
                 format!("non-ASCII whitespace symbol '{}' is not skipped", c.escape_unicode());
             handler.struct_span_warn(span, &msg).span_label(char_span, &msg).emit();
         }
+        EscapeError::MultipleSkippedLinesWarning => {
+            let msg = "multiple lines skipped by escaped newline";
+            let bottom_msg = "skipping everything up to and including this point";
+            handler.struct_span_warn(span, msg).span_label(span, bottom_msg).emit();
+        }
     }
 }
 

compiler/rustc_span/src/symbol.rs

@@ -335,6 +335,7 @@ symbols! {
         bitreverse,
         bitxor,
         bitxor_assign,
+        black_box,
         block,
         bool,
         borrowck_graphviz_format,

compiler/rustc_typeck/src/check/intrinsic.rs

@@ -102,6 +102,7 @@ pub fn intrinsic_operation_unsafety(intrinsic: Symbol) -> hir::Unsafety {
         | sym::maxnumf64
         | sym::type_name
         | sym::forget
+        | sym::black_box
         | sym::variant_count => hir::Unsafety::Normal,
         _ => hir::Unsafety::Unsafe,
     }
@@ -387,6 +388,8 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
                 (1, vec![param_ty; 2], tcx.types.bool)
             }
 
+            sym::black_box => (1, vec![param(0)], param(0)),
+
             other => {
                 tcx.sess.emit_err(UnrecognizedIntrinsicFunction { span: it.span, name: other });
                 return;

library/core/src/hint.rs

@@ -152,23 +152,19 @@ pub fn spin_loop() {
 /// backend used. Programs cannot rely on `black_box` for *correctness* in any way.
 ///
 /// [`std::convert::identity`]: crate::convert::identity
-#[cfg_attr(not(miri), inline)]
-#[cfg_attr(miri, inline(never))]
+#[inline]
 #[unstable(feature = "bench_black_box", issue = "64102")]
-#[cfg_attr(miri, allow(unused_mut))]
+#[cfg_attr(not(bootstrap), allow(unused_mut))]
 pub fn black_box<T>(mut dummy: T) -> T {
-    // We need to "use" the argument in some way LLVM can't introspect, and on
-    // targets that support it we can typically leverage inline assembly to do
-    // this. LLVM's interpretation of inline assembly is that it's, well, a black
-    // box. This isn't the greatest implementation since it probably deoptimizes
-    // more than we want, but it's so far good enough.
-
-    #[cfg(not(miri))] // This is just a hint, so it is fine to skip in Miri.
+    #[cfg(bootstrap)]
     // SAFETY: the inline assembly is a no-op.
     unsafe {
-        // FIXME: Cannot use `asm!` because it doesn't support MIPS and other architectures.
         llvm_asm!("" : : "r"(&mut dummy) : "memory" : "volatile");
+        dummy
     }
 
-    dummy
+    #[cfg(not(bootstrap))]
+    {
+        crate::intrinsics::black_box(dummy)
+    }
 }

library/core/src/intrinsics.rs

@@ -1933,6 +1933,12 @@ extern "rust-intrinsic" {
     /// which is UB if any of their inputs are `undef`.)
     #[rustc_const_unstable(feature = "const_intrinsic_raw_eq", issue = "none")]
     pub fn raw_eq<T>(a: &T, b: &T) -> bool;
+
+    /// See documentation of [`std::hint::black_box`] for details.
+    ///
+    /// [`std::hint::black_box`]: crate::hint::black_box
+    #[cfg(not(bootstrap))]
+    pub fn black_box<T>(dummy: T) -> T;
 }
 
 // Some functions are defined here because they accidentally got made

library/core/src/iter/traits/collect.rs

@@ -360,3 +360,61 @@ impl Extend<()> for () {
     }
     fn extend_one(&mut self, _item: ()) {}
 }
+
+#[stable(feature = "extend_for_tuple", since = "1.56.0")]
+impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB)
+where
+    ExtendA: Extend<A>,
+    ExtendB: Extend<B>,
+{
+    /// Allows to `extend` a tuple of collections that also implement `Extend`.
+    ///
+    /// See also: [`Iterator::unzip`]
+    ///
+    /// # Examples
+    /// ```
+    /// let mut tuple = (vec![0], vec![1]);
+    /// tuple.extend(vec![(2, 3), (4, 5), (6, 7)]);
+    /// assert_eq!(tuple.0, vec![0, 2, 4, 6]);
+    /// assert_eq!(tuple.1, vec![1, 3, 5, 7]);
+    ///
+    /// // also allows for arbitrarily nested tuples
+    /// let mut nested_tuple = (vec![(1, -1)], vec![(2, -2)]);
+    /// nested_tuple.extend(vec![((3, -3), (4, -4)), ((5, -5), (6, -6))]);
+    ///
+    /// assert_eq!(nested_tuple.0, vec![(1, -1), (3, -3), (5, -5)]);
+    /// assert_eq!(nested_tuple.1, vec![(2, -2), (4, -4), (6, -6)]);
+    /// ```
+    fn extend<T: IntoIterator<Item = (A, B)>>(&mut self, into_iter: T) {
+        let (a, b) = self;
+        let iter = into_iter.into_iter();
+
+        fn extend<'a, A, B>(
+            a: &'a mut impl Extend<A>,
+            b: &'a mut impl Extend<B>,
+        ) -> impl FnMut((), (A, B)) + 'a {
+            move |(), (t, u)| {
+                a.extend_one(t);
+                b.extend_one(u);
+            }
+        }
+
+        let (lower_bound, _) = iter.size_hint();
+        if lower_bound > 0 {
+            a.extend_reserve(lower_bound);
+            b.extend_reserve(lower_bound);
+        }
+
+        iter.fold((), extend(a, b));
+    }
+
+    fn extend_one(&mut self, item: (A, B)) {
+        self.0.extend_one(item.0);
+        self.1.extend_one(item.1);
+    }
+
+    fn extend_reserve(&mut self, additional: usize) {
+        self.0.extend_reserve(additional);
+        self.1.extend_reserve(additional);
+    }
+}