Auto merge of #59695 - Centril:rollup-88qffc2, r=Centril

Rollup of 8 pull requests

Successful merges:

 - #59470 (Document std::fs::File close behavior ignoring errors)
 - #59555 (update miri)
 - #59556 (update stdsimd)
 - #59596 (Forward formatter settings to bounds of `Range<T>` in `fmt::Debug` impl)
 - #59639 (Never return uninhabited values at all)
 - #59671 (Make some of lexer's API private)
 - #59685 (Add description for -Os and -Oz in rustc.1)
 - #59686 (Temporarily disable stack probing for gnux32.)

Failed merges:

r? @ghost

Cargo.lock

@@ -2054,18 +2054,6 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "rand"
-version = "0.5.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "rand"
 version = "0.6.1"
@@ -2093,14 +2081,6 @@ dependencies = [
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "rand_core"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "rand_core 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "rand_core"
 version = "0.3.0"
@@ -2560,7 +2540,7 @@ version = "1.0.0"
 dependencies = [
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4206,10 +4186,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum quote 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)" = "53fa22a1994bd0f9372d7a816207d8a2677ad0325b073f5c5332760f0fb62b5c"
 "checksum racer 2.1.21 (registry+https://github.com/rust-lang/crates.io-index)" = "37c88638777cc178684cf648ca0e1dad56646ce105b8593dfe665c436300adc3"
 "checksum rand 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8356f47b32624fef5b3301c1be97e5944ecdd595409cc5da11d05f211db6cfbd"
-"checksum rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e464cd887e869cddcae8792a4ee31d23c7edd516700695608f5b98c67ee0131c"
 "checksum rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ae9d223d52ae411a33cf7e54ec6034ec165df296ccd23533d671a28252b6f66a"
 "checksum rand_chacha 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "771b009e3a508cb67e8823dda454aaa5368c7bc1c16829fb77d3e980440dd34a"
-"checksum rand_core 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1961a422c4d189dfb50ffa9320bf1f2a9bd54ecb92792fb9477f99a1045f3372"
 "checksum rand_core 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0905b6b7079ec73b314d4c748701f6931eb79fd97c668caa3f1899b22b32c6db"
 "checksum rand_hc 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
 "checksum rand_isaac 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"

src/doc/man/rustc.1

@@ -261,7 +261,7 @@ full debug info with variable and type information.
 .RE
 .TP
 \fBopt\-level\fR=\fIVAL\fR
-Optimize with possible levels 0\[en]3
+Optimize with possible levels 0\[en]3, s (optimize for size), or z (for minimal size)
 
 .SH ENVIRONMENT
 

src/libcore/ops/range.rs

@@ -85,7 +85,10 @@ pub struct Range<Idx> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{:?}..{:?}", self.start, self.end)
+        self.start.fmt(fmt)?;
+        write!(fmt, "..")?;
+        self.end.fmt(fmt)?;
+        Ok(())
     }
 }
 
@@ -184,7 +187,9 @@ pub struct RangeFrom<Idx> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{:?}..", self.start)
+        self.start.fmt(fmt)?;
+        write!(fmt, "..")?;
+        Ok(())
     }
 }
 
@@ -266,7 +271,9 @@ pub struct RangeTo<Idx> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "..{:?}", self.end)
+        write!(fmt, "..")?;
+        self.end.fmt(fmt)?;
+        Ok(())
     }
 }
 
@@ -467,7 +474,10 @@ impl<Idx> RangeInclusive<Idx> {
 #[stable(feature = "inclusive_range", since = "1.26.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "{:?}..={:?}", self.start, self.end)
+        self.start.fmt(fmt)?;
+        write!(fmt, "..=")?;
+        self.end.fmt(fmt)?;
+        Ok(())
     }
 }
 
@@ -602,7 +612,9 @@ pub struct RangeToInclusive<Idx> {
 #[stable(feature = "inclusive_range", since = "1.26.0")]
 impl<Idx: fmt::Debug> fmt::Debug for RangeToInclusive<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        write!(fmt, "..={:?}", self.end)
+        write!(fmt, "..=")?;
+        self.end.fmt(fmt)?;
+        Ok(())
     }
 }
 

src/librustc_codegen_ssa/mir/block.rs

@@ -238,6 +238,13 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
             }
         }
+        if self.fn_ty.ret.layout.abi.is_uninhabited() {
+            // Functions with uninhabited return values are marked `noreturn`,
+            // so we should make sure that we never actually do.
+            bx.abort();
+            bx.unreachable();
+            return;
+        }
         let llval = match self.fn_ty.ret.mode {
             PassMode::Ignore(IgnoreMode::Zst) | PassMode::Indirect(..) => {
                 bx.ret_void();

src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs

@@ -5,7 +5,8 @@ pub fn target() -> TargetResult {
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-mx32".to_string());
-    base.stack_probes = true;
+    // BUG: temporarily workaround #59674
+    base.stack_probes = false;
     base.has_elf_tls = false;
     // BUG(GabrielMajeri): disabling the PLT on x86_64 Linux with x32 ABI
     // breaks code gen. See LLVM bug 36743

src/libstd/fs.rs

@@ -21,7 +21,9 @@ use crate::time::SystemTime;
 /// it was opened with. Files also implement [`Seek`] to alter the logical cursor
 /// that the file contains internally.
 ///
-/// Files are automatically closed when they go out of scope.
+/// Files are automatically closed when they go out of scope.  Errors detected
+/// on closing are ignored by the implementation of `Drop`.  Use the method
+/// [`sync_all`] if these errors must be manually handled.
 ///
 /// # Examples
 ///
@@ -84,6 +86,7 @@ use crate::time::SystemTime;
 /// [`Read`]: ../io/trait.Read.html
 /// [`Write`]: ../io/trait.Write.html
 /// [`BufReader<R>`]: ../io/struct.BufReader.html
+/// [`sync_all`]: struct.File.html#method.sync_all
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct File {
     inner: fs_imp::File,
@@ -391,9 +394,13 @@ impl File {
 
     /// Attempts to sync all OS-internal metadata to disk.
     ///
-    /// This function will attempt to ensure that all in-core data reaches the
+    /// This function will attempt to ensure that all in-memory data reaches the
     /// filesystem before returning.
     ///
+    /// This can be used to handle errors that would otherwise only be caught
+    /// when the `File` is closed.  Dropping a file will ignore errors in
+    /// synchronizing this in-memory data.
+    ///
     /// # Examples
     ///
     /// ```no_run

src/libsyntax/parse/lexer/mod.rs

@@ -43,16 +43,16 @@ pub struct UnmatchedBrace {
 }
 
 pub struct StringReader<'a> {
-    pub sess: &'a ParseSess,
+    crate sess: &'a ParseSess,
     /// The absolute offset within the source_map of the next character to read
-    pub next_pos: BytePos,
+    crate next_pos: BytePos,
     /// The absolute offset within the source_map of the current character
-    pub pos: BytePos,
+    crate pos: BytePos,
     /// The current character (which has been read from self.pos)
-    pub ch: Option<char>,
-    pub source_file: Lrc<syntax_pos::SourceFile>,
+    crate ch: Option<char>,
+    crate source_file: Lrc<syntax_pos::SourceFile>,
     /// Stop reading src at this index.
-    pub end_src_index: usize,
+    crate end_src_index: usize,
     // cached:
     peek_tok: token::Token,
     peek_span: Span,
@@ -126,7 +126,7 @@ impl<'a> StringReader<'a> {
     }
 
     /// Immutably extract string if found at current position with given delimiters
-    pub fn peek_delimited(&self, from_ch: char, to_ch: char) -> Option<String> {
+    fn peek_delimited(&self, from_ch: char, to_ch: char) -> Option<String> {
         let mut pos = self.pos;
         let mut idx = self.src_index(pos);
         let mut ch = char_at(&self.src, idx);
@@ -191,7 +191,7 @@ impl<'a> StringReader<'a> {
         self.fatal_span(self.peek_span, m)
     }
 
-    pub fn emit_fatal_errors(&mut self) {
+    crate fn emit_fatal_errors(&mut self) {
         for err in &mut self.fatal_errs {
             err.emit();
         }

src/test/codegen/noreturn-uninhabited.rs

@@ -0,0 +1,32 @@
+// compile-flags: -g -C no-prepopulate-passes
+// ignore-tidy-linelength
+
+#![crate_type = "lib"]
+
+#[derive(Clone, Copy)]
+pub enum EmptyEnum {}
+
+#[no_mangle]
+pub fn empty(x: &EmptyEnum) -> EmptyEnum {
+    // CHECK: @empty({{.*}}) unnamed_addr #0
+    // CHECK-NOT: ret void
+    // CHECK: call void @llvm.trap()
+    // CHECK: unreachable
+    *x
+}
+
+pub struct Foo(String, EmptyEnum);
+
+#[no_mangle]
+pub fn foo(x: String, y: &EmptyEnum) -> Foo {
+    // CHECK: @foo({{.*}}) unnamed_addr #0
+    // CHECK-NOT: ret %Foo
+    // CHECK: call void @llvm.trap()
+    // CHECK: unreachable
+    Foo(x, *y)
+}
+
+// CHECK: attributes #0 = {{{.*}} noreturn {{.*}}}
+
+// CHECK: DISubprogram(name: "empty", {{.*}} DIFlagNoReturn
+// CHECK: DISubprogram(name: "foo", {{.*}} DIFlagNoReturn

src/tools/rustc-workspace-hack/Cargo.toml

@@ -57,7 +57,7 @@ features = [
 [dependencies]
 curl-sys = { version = "0.4.13", features = ["http2", "libnghttp2-sys"], optional = true }
 parking_lot = { version = "0.7", features = ['nightly'] }
-rand = { version = "0.5.5", features = ["i128_support"] }
+rand = { version = "0.6.1", features = ["i128_support"] }
 serde = { version = "1.0.82", features = ['derive'] }
 serde_json = { version = "1.0.31", features = ["raw_value"] }
 smallvec = { version = "0.6", features = ['union', 'may_dangle'] }