19 files changed, 192 insertions, 98 deletions
diff --git a/Cargo.lock b/Cargo.lock
index 4a71884cb08..3cc0026bf45 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,7 +17,7 @@ dependencies = [
 name = "alloc"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_xorshift 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -107,7 +107,7 @@ version = "0.1.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -465,7 +465,7 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.8"
+version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -751,7 +751,7 @@ name = "dlmalloc"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -917,7 +917,7 @@ name = "fortanix-sgx-abi"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -1769,7 +1769,7 @@ dependencies = [
 name = "panic_abort"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1779,7 +1779,7 @@ name = "panic_unwind"
 version = "0.0.0"
 dependencies = [
  "alloc 0.0.0",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
  "unwind 0.0.0",
@@ -1964,7 +1964,7 @@ name = "profiler_builtins"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2056,18 +2056,6 @@ dependencies = [
 
 [[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"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
@@ -2095,14 +2083,6 @@ dependencies = [
 
 [[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"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
@@ -2499,7 +2479,7 @@ name = "rustc-demangle"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -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)",
@@ -2599,7 +2579,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2826,7 +2806,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2888,7 +2868,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3009,7 +2989,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -3276,7 +3256,7 @@ dependencies = [
  "alloc 0.0.0",
  "backtrace-sys 0.1.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "dlmalloc 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fortanix-sgx-abi 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3850,7 +3830,7 @@ name = "unwind"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -4046,7 +4026,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum colored 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b0aa3473e85a3161b59845d6096b289bb577874cafeaf75ea1b1beaa6572c7fc"
 "checksum commoncrypto 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d056a8586ba25a1e4d61cb090900e495952c7886786fc55f909ab2f819b69007"
 "checksum commoncrypto-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1fed34f46747aa73dfaa578069fd8279d2818ade2b55f38f22a9401c7f4083e2"
-"checksum compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "a28c3898d0c57b26fa6f92de141ba665fa5ac5179f795db06db408be84302395"
+"checksum compiler_builtins 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "d7de11892d9f9f1bc76d43011c8233d27d58300d629dc9dfb51b6626ef7f6077"
 "checksum compiletest_rs 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)" = "56c799b1f7142badf3b047b4c1f2074cc96b6b784fb2432f2ed9c87da0a03749"
 "checksum constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8ff012e225ce166d4422e0e78419d901719760f62ae2b7969ca6b564d1b54a9e"
 "checksum core-foundation 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4e2640d6d0bf22e82bed1b73c6aef8d5dd31e5abe6666c57e6d45e2649f4f887"
@@ -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"
diff --git a/src/ci/docker/scripts/freebsd-toolchain.sh b/src/ci/docker/scripts/freebsd-toolchain.sh
index 04483e24925..b1ac490a878 100755
--- a/src/ci/docker/scripts/freebsd-toolchain.sh
+++ b/src/ci/docker/scripts/freebsd-toolchain.sh
@@ -1,4 +1,6 @@
 #!/bin/bash
+# ignore-tidy-linelength
+
 set -eux
 
 arch=$1
@@ -55,7 +57,9 @@ for lib in c++ c_nonshared compiler_rt execinfo gcc pthread rt ssp_nonshared; do
   files_to_extract=("${files_to_extract[@]}" "./usr/lib/lib${lib}.*")
 done
 
-URL=https://download.freebsd.org/ftp/releases/${freebsd_arch}/${freebsd_version}-RELEASE/base.txz
+# Originally downloaded from:
+# https://download.freebsd.org/ftp/releases/${freebsd_arch}/${freebsd_version}-RELEASE/base.txz
+URL=https://s3-us-west-1.amazonaws.com/rust-lang-ci2/rust-ci-mirror/2019-04-04-freebsd-${freebsd_arch}-${freebsd_version}-RELEASE-base.txz
 curl "$URL" | tar xJf - -C "$sysroot" --wildcards "${files_to_extract[@]}"
 
 # Fix up absolute symlinks from the system image.  This can be removed
diff --git a/src/doc/man/rustc.1 b/src/doc/man/rustc.1
index 2faf0c2e3e1..3788e3c864e 100644
--- a/src/doc/man/rustc.1
+++ b/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
 
diff --git a/src/libcore/ops/range.rs b/src/libcore/ops/range.rs
index 4f71c8e7949..5b6023f2e2c 100644
--- a/src/libcore/ops/range.rs
+++ b/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(())
     }
 }
 
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index 65f7e023fa2..e64c847db65 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/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();
diff --git a/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs b/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs
index 0b2d7aacc4d..73151b194de 100644
--- a/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs
+++ b/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
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 875483518e8..86ad334d886 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -19,7 +19,7 @@ panic_unwind = { path = "../libpanic_unwind", optional = true }
 panic_abort = { path = "../libpanic_abort" }
 core = { path = "../libcore" }
 libc = { version = "0.2.51", default-features = false, features = ['rustc-dep-of-std'] }
-compiler_builtins = { version = "0.1.8" }
+compiler_builtins = { version = "0.1.9" }
 profiler_builtins = { path = "../libprofiler_builtins", optional = true }
 unwind = { path = "../libunwind" }
 rustc-demangle = { version = "0.1.10", features = ['rustc-dep-of-std'] }
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index 89d5b2ff30f..b9fcc2365fa 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -627,7 +627,11 @@ impl<T, S> HashSet<T, S>
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn is_subset(&self, other: &HashSet<T, S>) -> bool {
-        self.iter().all(|v| other.contains(v))
+        if self.len() <= other.len() {
+            self.iter().all(|v| other.contains(v))
+        } else {
+            false
+        }
     }
 
     /// Returns `true` if the set is a superset of another,
diff --git a/src/libstd/ffi/os_str.rs b/src/libstd/ffi/os_str.rs
index 01e7a57cd00..13aee783750 100644
--- a/src/libstd/ffi/os_str.rs
+++ b/src/libstd/ffi/os_str.rs
@@ -960,6 +960,7 @@ impl IntoInner<Buf> for OsString {
 }
 
 impl AsInner<Slice> for OsStr {
+    #[inline]
     fn as_inner(&self) -> &Slice {
         &self.inner
     }
diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index 29f4c78e27b..14ff4d72f87 100644
--- a/src/libstd/fs.rs
+++ b/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
diff --git a/src/libstd/sys/unix/time.rs b/src/libstd/sys/unix/time.rs
index 127ae6aa104..e21c32cd91b 100644
--- a/src/libstd/sys/unix/time.rs
+++ b/src/libstd/sys/unix/time.rs
@@ -114,7 +114,8 @@ impl Hash for Timespec {
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 mod inner {
     use crate::fmt;
-    use crate::sync::Once;
+    use crate::mem;
+    use crate::sync::atomic::{AtomicUsize, Ordering::SeqCst};
     use crate::sys::cvt;
     use crate::sys_common::mul_div_u64;
     use crate::time::Duration;
@@ -229,18 +230,30 @@ mod inner {
         Some(mul_div_u64(nanos, info.denom as u64, info.numer as u64))
     }
 
-    fn info() -> &'static libc::mach_timebase_info {
+    fn info() -> libc::mach_timebase_info {
         static mut INFO: libc::mach_timebase_info = libc::mach_timebase_info {
             numer: 0,
             denom: 0,
         };
-        static ONCE: Once = Once::new();
+        static STATE: AtomicUsize = AtomicUsize::new(0);
 
         unsafe {
-            ONCE.call_once(|| {
-                libc::mach_timebase_info(&mut INFO);
-            });
-            &INFO
+            // If a previous thread has filled in this global state, use that.
+            if STATE.load(SeqCst) == 2 {
+                return INFO;
+            }
+
+            // ... otherwise learn for ourselves ...
+            let mut info = mem::zeroed();
+            libc::mach_timebase_info(&mut info);
+
+            // ... and attempt to be the one thread that stores it globally for
+            // all other threads
+            if STATE.compare_exchange(0, 1, SeqCst, SeqCst).is_ok() {
+                INFO = info;
+                STATE.store(2, SeqCst);
+            }
+            return info;
         }
     }
 }
diff --git a/src/libstd/sys/windows/time.rs b/src/libstd/sys/windows/time.rs
index 4c9d2aee157..e0f0e3a1a45 100644
--- a/src/libstd/sys/windows/time.rs
+++ b/src/libstd/sys/windows/time.rs
@@ -173,7 +173,7 @@ fn intervals2dur(intervals: u64) -> Duration {
 
 mod perf_counter {
     use super::{NANOS_PER_SEC};
-    use crate::sync::Once;
+    use crate::sync::atomic::{AtomicUsize, Ordering::SeqCst};
     use crate::sys_common::mul_div_u64;
     use crate::sys::c;
     use crate::sys::cvt;
@@ -210,13 +210,25 @@ mod perf_counter {
 
     fn frequency() -> c::LARGE_INTEGER {
         static mut FREQUENCY: c::LARGE_INTEGER = 0;
-        static ONCE: Once = Once::new();
+        static STATE: AtomicUsize = AtomicUsize::new(0);
 
         unsafe {
-            ONCE.call_once(|| {
-                cvt(c::QueryPerformanceFrequency(&mut FREQUENCY)).unwrap();
-            });
-            FREQUENCY
+            // If a previous thread has filled in this global state, use that.
+            if STATE.load(SeqCst) == 2 {
+                return FREQUENCY;
+            }
+
+            // ... otherwise learn for ourselves ...
+            let mut frequency = 0;
+            cvt(c::QueryPerformanceFrequency(&mut frequency)).unwrap();
+
+            // ... and attempt to be the one thread that stores it globally for
+            // all other threads
+            if STATE.compare_exchange(0, 1, SeqCst, SeqCst).is_ok() {
+                FREQUENCY = frequency;
+                STATE.store(2, SeqCst);
+            }
+            return frequency;
         }
     }
 
diff --git a/src/libstd/sys_common/os_str_bytes.rs b/src/libstd/sys_common/os_str_bytes.rs
index 7cc93477a73..a4961974d89 100644
--- a/src/libstd/sys_common/os_str_bytes.rs
+++ b/src/libstd/sys_common/os_str_bytes.rs
@@ -236,9 +236,11 @@ pub trait OsStrExt {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl OsStrExt for OsStr {
+    #[inline]
     fn from_bytes(slice: &[u8]) -> &OsStr {
         unsafe { mem::transmute(slice) }
     }
+    #[inline]
     fn as_bytes(&self) -> &[u8] {
         &self.as_inner().inner
     }
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index cd4944deadb..5557e281a66 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -1,10 +1,9 @@
 use crate::ast::{self, Ident};
-use crate::source_map::{SourceMap, FilePathMapping};
 use crate::parse::{token, ParseSess};
 use crate::symbol::Symbol;
 
 use errors::{Applicability, FatalError, Diagnostic, DiagnosticBuilder};
-use syntax_pos::{BytePos, CharPos, Pos, Span, NO_EXPANSION};
+use syntax_pos::{BytePos, Pos, Span, NO_EXPANSION};
 use core::unicode::property::Pattern_White_Space;
 
 use std::borrow::Cow;
@@ -43,16 +42,16 @@ 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 +125,7 @@ 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 +190,7 @@ 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();
         }
@@ -667,14 +666,9 @@ impl<'a> StringReader<'a> {
                     return None;
                 }
 
-                // I guess this is the only way to figure out if
-                // we're at the beginning of the file...
-                let smap = SourceMap::new(FilePathMapping::empty());
-                smap.files.borrow_mut().source_files.push(self.source_file.clone());
-                let loc = smap.lookup_char_pos_adj(self.pos);
-                debug!("Skipping a shebang");
-                if loc.line == 1 && loc.col == CharPos(0) {
-                    // FIXME: Add shebang "token", return it
+                let is_beginning_of_file = self.pos == self.source_file.start_pos;
+                if is_beginning_of_file {
+                    debug!("Skipping a shebang");
                     let start = self.pos;
                     while !self.ch_is('\n') && !self.is_eof() {
                         self.bump();
@@ -1911,7 +1905,7 @@ mod tests {
 
     use crate::ast::{Ident, CrateConfig};
     use crate::symbol::Symbol;
-    use crate::source_map::SourceMap;
+    use crate::source_map::{SourceMap, FilePathMapping};
     use crate::feature_gate::UnstableFeatures;
     use crate::parse::token;
     use crate::diagnostics::plugin::ErrorMap;
diff --git a/src/stdsimd b/src/stdsimd
-Subproject 12bdc2ed6b32653866d02b42f0885d9cd8bd295
+Subproject 2792b45c975880038240d477adb0d66f760ac04
diff --git a/src/test/codegen/noreturn-uninhabited.rs b/src/test/codegen/noreturn-uninhabited.rs
new file mode 100644
index 00000000000..1b65da9f287
--- /dev/null
+++ b/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
diff --git a/src/test/run-pass/issue-59020.rs b/src/test/run-pass/issue-59020.rs
new file mode 100644
index 00000000000..a2b11764a2f
--- /dev/null
+++ b/src/test/run-pass/issue-59020.rs
@@ -0,0 +1,27 @@
+// edition:2018
+// run-pass
+// ignore-emscripten no threads support
+
+use std::thread;
+use std::time::Duration;
+
+fn main() {
+    let t1 = thread::spawn(|| {
+        let sleep = Duration::new(0,100_000);
+        for _ in 0..100 {
+            println!("Parking1");
+            thread::park_timeout(sleep);
+        }
+    });
+
+    let t2 = thread::spawn(|| {
+        let sleep = Duration::new(0,100_000);
+        for _ in 0..100 {
+            println!("Parking2");
+            thread::park_timeout(sleep);
+        }
+    });
+
+    t1.join().expect("Couldn't join thread 1");
+    t2.join().expect("Couldn't join thread 2");
+}
diff --git a/src/tools/miri b/src/tools/miri
-Subproject 72b4ee0381decf609204e5548c1f5e79bdfb18b
+Subproject 82f9a0173011b96411d315b332754ee6b35cf00
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index 1aba52bafbb..d51841cd650 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/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'] }