Auto merge of #73402 - Dylan-DPC:rollup-8udzpfu, r=Dylan-DPC

Rollup of 8 pull requests

Successful merges:

 - #73237 (Check for overflow in DroplessArena and align returned memory)
 - #73339 (Don't run generator transform when there's a TyErr)
 - #73372 (Re-order correctly the sections in the sidebar)
 - #73373 (Use track caller for bug! macro)
 - #73380 (Add more info to `x.py build --help` on default value for `-j JOBS`.)
 - #73381 (Fix typo in docs of std::mem)
 - #73389 (Use `Ipv4Addr::from<[u8; 4]>` when possible)
 - #73400 (Fix forge-platform-support URL)

Failed merges:

r? @ghost

14 files changed, 87 insertions, 85 deletions

diff --git a/RELEASES.md b/RELEASES.md
index 3ae3417a9b4..006682f5059 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -912,7 +912,7 @@ Compatibility Notes
 [`Duration::mul_f32`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f32
 [`Duration::mul_f64`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.mul_f64
 [`any::type_name`]: https://doc.rust-lang.org/std/any/fn.type_name.html
-[forge-platform-support]: https://forge.rust-lang.org/platform-support.html
+[forge-platform-support]: https://forge.rust-lang.org/release/platform-support.html
 [pipeline-internals]: https://internals.rust-lang.org/t/evaluating-pipelined-rustc-compilation/10199
 
 Version 1.37.0 (2019-08-15)
diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index cfaa43f3970..37261153574 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -149,7 +149,12 @@ To learn more about a subcommand, run `./x.py <subcommand> -h`",
             "N",
         );
         opts.optopt("", "src", "path to the root of the rust checkout", "DIR");
-        opts.optopt("j", "jobs", "number of jobs to run in parallel", "JOBS");
+        let j_msg = format!(
+            "number of jobs to run in parallel; \
+             defaults to {} (this host's logical CPU count)",
+            num_cpus::get()
+        );
+        opts.optopt("j", "jobs", &j_msg, "JOBS");
         opts.optflag("h", "help", "print this help message");
         opts.optopt(
             "",
diff --git a/src/libcore/mem/mod.rs b/src/libcore/mem/mod.rs
index d1f5cb44913..8bce980cadd 100644
--- a/src/libcore/mem/mod.rs
+++ b/src/libcore/mem/mod.rs
@@ -129,7 +129,7 @@ pub use crate::intrinsics::transmute;
 /// erring on the side of (double-)dropping.
 ///
 /// Also, `ManuallyDrop` prevents us from having to "touch" `v` after transferring the
-/// ownership to `s` - the final step of interacting with `v` to dispoe of it without
+/// ownership to `s` — the final step of interacting with `v` to dispose of it without
 /// running its destructor is entirely avoided.
 ///
 /// [drop]: fn.drop.html
diff --git a/src/libcore/panic.rs b/src/libcore/panic.rs
index 1ffd493d813..c7009b76e81 100644
--- a/src/libcore/panic.rs
+++ b/src/libcore/panic.rs
@@ -39,8 +39,7 @@ pub struct PanicInfo<'a> {
 impl<'a> PanicInfo<'a> {
     #[unstable(
         feature = "panic_internals",
-        reason = "internal details of the implementation of the `panic!` \
-                         and related macros",
+        reason = "internal details of the implementation of the `panic!` and related macros",
         issue = "none"
     )]
     #[doc(hidden)]
@@ -55,8 +54,7 @@ impl<'a> PanicInfo<'a> {
 
     #[unstable(
         feature = "panic_internals",
-        reason = "internal details of the implementation of the `panic!` \
-                         and related macros",
+        reason = "internal details of the implementation of the `panic!` and related macros",
         issue = "none"
     )]
     #[doc(hidden)]
@@ -244,8 +242,7 @@ impl<'a> Location<'a> {
 impl<'a> Location<'a> {
     #![unstable(
         feature = "panic_internals",
-        reason = "internal details of the implementation of the `panic!` \
-                          and related macros",
+        reason = "internal details of the implementation of the `panic!` and related macros",
         issue = "none"
     )]
     #[doc(hidden)]
diff --git a/src/libcore/panicking.rs b/src/libcore/panicking.rs
index 3ed5e65e11c..766c69a5f94 100644
--- a/src/libcore/panicking.rs
+++ b/src/libcore/panicking.rs
@@ -22,8 +22,7 @@
 #![allow(dead_code, missing_docs)]
 #![unstable(
     feature = "core_panic",
-    reason = "internal details of the implementation of the `panic!` \
-              and related macros",
+    reason = "internal details of the implementation of the `panic!` and related macros",
     issue = "none"
 )]
 
diff --git a/src/librustc_arena/lib.rs b/src/librustc_arena/lib.rs
index 4a2a0de0e21..66c31cbebcc 100644
--- a/src/librustc_arena/lib.rs
+++ b/src/librustc_arena/lib.rs
@@ -333,13 +333,6 @@ impl Default for DroplessArena {
 }
 
 impl DroplessArena {
-    #[inline]
-    fn align(&self, align: usize) {
-        let final_address = ((self.ptr.get() as usize) + align - 1) & !(align - 1);
-        self.ptr.set(final_address as *mut u8);
-        assert!(self.ptr <= self.end);
-    }
-
     #[inline(never)]
     #[cold]
     fn grow(&self, additional: usize) {
@@ -370,22 +363,42 @@ impl DroplessArena {
         }
     }
 
+    /// Allocates a byte slice with specified size and alignment from the
+    /// current memory chunk. Returns `None` if there is no free space left to
+    /// satisfy the request.
     #[inline]
-    pub fn alloc_raw(&self, bytes: usize, align: usize) -> &mut [u8] {
-        unsafe {
-            assert!(bytes != 0);
-
-            self.align(align);
+    fn alloc_raw_without_grow(&self, bytes: usize, align: usize) -> Option<*mut u8> {
+        let ptr = self.ptr.get() as usize;
+        let end = self.end.get() as usize;
+        // The allocation request fits into the current chunk iff:
+        //
+        // let aligned = align_to(ptr, align);
+        // ptr <= aligned && aligned + bytes <= end
+        //
+        // Except that we work with fixed width integers and need to be careful
+        // about potential overflow in the calcuation. If the overflow does
+        // happen, then we definitely don't have enough free and need to grow
+        // the arena.
+        let aligned = ptr.checked_add(align - 1)? & !(align - 1);
+        let new_ptr = aligned.checked_add(bytes)?;
+        if new_ptr <= end {
+            self.ptr.set(new_ptr as *mut u8);
+            Some(aligned as *mut u8)
+        } else {
+            None
+        }
+    }
 
-            let future_end = intrinsics::arith_offset(self.ptr.get(), bytes as isize);
-            if (future_end as *mut u8) > self.end.get() {
-                self.grow(bytes);
+    #[inline]
+    pub fn alloc_raw(&self, bytes: usize, align: usize) -> *mut u8 {
+        assert!(bytes != 0);
+        loop {
+            if let Some(a) = self.alloc_raw_without_grow(bytes, align) {
+                break a;
             }
-
-            let ptr = self.ptr.get();
-            // Set the pointer past ourselves
-            self.ptr.set(intrinsics::arith_offset(self.ptr.get(), bytes as isize) as *mut u8);
-            slice::from_raw_parts_mut(ptr, bytes)
+            // No free space left. Allocate a new chunk to satisfy the request.
+            // On failure the grow will panic or abort.
+            self.grow(bytes);
         }
     }
 
@@ -393,7 +406,7 @@ impl DroplessArena {
     pub fn alloc<T>(&self, object: T) -> &mut T {
         assert!(!mem::needs_drop::<T>());
 
-        let mem = self.alloc_raw(mem::size_of::<T>(), mem::align_of::<T>()) as *mut _ as *mut T;
+        let mem = self.alloc_raw(mem::size_of::<T>(), mem::align_of::<T>()) as *mut T;
 
         unsafe {
             // Write into uninitialized memory.
@@ -418,13 +431,11 @@ impl DroplessArena {
         assert!(mem::size_of::<T>() != 0);
         assert!(!slice.is_empty());
 
-        let mem = self.alloc_raw(slice.len() * mem::size_of::<T>(), mem::align_of::<T>()) as *mut _
-            as *mut T;
+        let mem = self.alloc_raw(slice.len() * mem::size_of::<T>(), mem::align_of::<T>()) as *mut T;
 
         unsafe {
-            let arena_slice = slice::from_raw_parts_mut(mem, slice.len());
-            arena_slice.copy_from_slice(slice);
-            arena_slice
+            mem.copy_from_nonoverlapping(slice.as_ptr(), slice.len());
+            slice::from_raw_parts_mut(mem, slice.len())
         }
     }
 
@@ -467,7 +478,7 @@ impl DroplessArena {
                     return &mut [];
                 }
                 let size = len.checked_mul(mem::size_of::<T>()).unwrap();
-                let mem = self.alloc_raw(size, mem::align_of::<T>()) as *mut _ as *mut T;
+                let mem = self.alloc_raw(size, mem::align_of::<T>()) as *mut T;
                 unsafe { self.write_from_iter(iter, len, mem) }
             }
             (_, _) => {
@@ -482,7 +493,7 @@ impl DroplessArena {
                         let len = vec.len();
                         let start_ptr = self
                             .alloc_raw(len * mem::size_of::<T>(), mem::align_of::<T>())
-                            as *mut _ as *mut T;
+                            as *mut T;
                         vec.as_ptr().copy_to_nonoverlapping(start_ptr, len);
                         vec.set_len(0);
                         slice::from_raw_parts_mut(start_ptr, len)
@@ -526,8 +537,7 @@ pub struct DropArena {
 impl DropArena {
     #[inline]
     pub unsafe fn alloc<T>(&self, object: T) -> &mut T {
-        let mem =
-            self.arena.alloc_raw(mem::size_of::<T>(), mem::align_of::<T>()) as *mut _ as *mut T;
+        let mem = self.arena.alloc_raw(mem::size_of::<T>(), mem::align_of::<T>()) as *mut T;
         // Write into uninitialized memory.
         ptr::write(mem, object);
         let result = &mut *mem;
@@ -550,7 +560,7 @@ impl DropArena {
         let start_ptr = self
             .arena
             .alloc_raw(len.checked_mul(mem::size_of::<T>()).unwrap(), mem::align_of::<T>())
-            as *mut _ as *mut T;
+            as *mut T;
 
         let mut destructors = self.destructors.borrow_mut();
         // Reserve space for the destructors so we can't panic while adding them
diff --git a/src/librustc_middle/macros.rs b/src/librustc_middle/macros.rs
index 88ddd96eec8..a5482b7bdcf 100644
--- a/src/librustc_middle/macros.rs
+++ b/src/librustc_middle/macros.rs
@@ -1,16 +1,20 @@
 #[macro_export]
 macro_rules! bug {
-    () => ( bug!("impossible case reached") );
-    ($($message:tt)*) => ({
-        $crate::util::bug::bug_fmt(file!(), line!(), format_args!($($message)*))
-    })
+    () => ( $crate::bug!("impossible case reached") );
+    ($msg:expr) => ({ $crate::util::bug::bug_fmt(::std::format_args!($msg)) });
+    ($msg:expr,) => ({ $crate::bug!($msg) });
+    ($fmt:expr, $($arg:tt)+) => ({
+        $crate::util::bug::bug_fmt(::std::format_args!($fmt, $($arg)+))
+    });
 }
 
 #[macro_export]
 macro_rules! span_bug {
-    ($span:expr, $($message:tt)*) => ({
-        $crate::util::bug::span_bug_fmt(file!(), line!(), $span, format_args!($($message)*))
-    })
+    ($span:expr, $msg:expr) => ({ $crate::util::bug::span_bug_fmt($span, ::std::format_args!($msg)) });
+    ($span:expr, $msg:expr,) => ({ $crate::span_bug!($span, $msg) });
+    ($span:expr, $fmt:expr, $($arg:tt)+) => ({
+        $crate::util::bug::span_bug_fmt($span, ::std::format_args!($fmt, $($arg)+))
+    });
 }
 
 ///////////////////////////////////////////////////////////////////////////
diff --git a/src/librustc_middle/ty/context.rs b/src/librustc_middle/ty/context.rs
index d5be3508d2d..de2e1046f1c 100644
--- a/src/librustc_middle/ty/context.rs
+++ b/src/librustc_middle/ty/context.rs
@@ -189,8 +189,7 @@ fn validate_hir_id_for_typeck_tables(
         if hir_id.owner != hir_owner {
             ty::tls::with(|tcx| {
                 bug!(
-                    "node {} with HirId::owner {:?} cannot be placed in \
-                     TypeckTables with hir_owner {:?}",
+                    "node {} with HirId::owner {:?} cannot be placed in TypeckTables with hir_owner {:?}",
                     tcx.hir().node_to_string(hir_id),
                     hir_id.owner,
                     hir_owner
diff --git a/src/librustc_middle/ty/list.rs b/src/librustc_middle/ty/list.rs
index 161783bb370..76c72e4c260 100644
--- a/src/librustc_middle/ty/list.rs
+++ b/src/librustc_middle/ty/list.rs
@@ -55,7 +55,7 @@ impl<T: Copy> List<T> {
             .dropless
             .alloc_raw(size, cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
         unsafe {
-            let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
+            let result = &mut *(mem as *mut List<T>);
             // Write the length
             result.len = slice.len();
 
diff --git a/src/librustc_middle/util/bug.rs b/src/librustc_middle/util/bug.rs
index 54cd8a29f94..9c3a97d8332 100644
--- a/src/librustc_middle/util/bug.rs
+++ b/src/librustc_middle/util/bug.rs
@@ -3,34 +3,31 @@
 use crate::ty::{tls, TyCtxt};
 use rustc_span::{MultiSpan, Span};
 use std::fmt;
+use std::panic::Location;
 
 #[cold]
 #[inline(never)]
-pub fn bug_fmt(file: &'static str, line: u32, args: fmt::Arguments<'_>) -> ! {
+#[track_caller]
+pub fn bug_fmt(args: fmt::Arguments<'_>) -> ! {
     // this wrapper mostly exists so I don't have to write a fully
     // qualified path of None::<Span> inside the bug!() macro definition
-    opt_span_bug_fmt(file, line, None::<Span>, args);
+    opt_span_bug_fmt(None::<Span>, args, Location::caller());
 }
 
 #[cold]
 #[inline(never)]
-pub fn span_bug_fmt<S: Into<MultiSpan>>(
-    file: &'static str,
-    line: u32,
-    span: S,
-    args: fmt::Arguments<'_>,
-) -> ! {
-    opt_span_bug_fmt(file, line, Some(span), args);
+#[track_caller]
+pub fn span_bug_fmt<S: Into<MultiSpan>>(span: S, args: fmt::Arguments<'_>) -> ! {
+    opt_span_bug_fmt(Some(span), args, Location::caller());
 }
 
 fn opt_span_bug_fmt<S: Into<MultiSpan>>(
-    file: &'static str,
-    line: u32,
     span: Option<S>,
     args: fmt::Arguments<'_>,
+    location: &Location<'_>,
 ) -> ! {
     tls::with_opt(move |tcx| {
-        let msg = format!("{}:{}: {}", file, line, args);
+        let msg = format!("{}: {}", location, args);
         match (tcx, span) {
             (Some(tcx), Some(span)) => tcx.sess.diagnostic().span_bug(span, &msg),
             (Some(tcx), None) => tcx.sess.diagnostic().bug(&msg),
diff --git a/src/librustc_mir/transform/generator.rs b/src/librustc_mir/transform/generator.rs
index 25b6a51d91b..acadb5385c9 100644
--- a/src/librustc_mir/transform/generator.rs
+++ b/src/librustc_mir/transform/generator.rs
@@ -1222,7 +1222,11 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
                     movability == hir::Movability::Movable,
                 )
             }
-            _ => bug!(),
+            _ => {
+                tcx.sess
+                    .delay_span_bug(body.span, &format!("unexpected generator type {}", gen_ty));
+                return;
+            }
         };
 
         // Compute GeneratorState<yield_ty, return_ty>
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 07631093edd..1681b73d0c2 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -4338,6 +4338,8 @@ fn sidebar_trait(buf: &mut Buffer, it: &clean::Item, t: &clean::Trait) {
         }
     }
 
+    sidebar.push_str(&sidebar_assoc_items(it));
+
     sidebar.push_str("<a class=\"sidebar-title\" href=\"#implementors\">Implementors</a>");
     if t.auto {
         sidebar.push_str(
@@ -4346,8 +4348,6 @@ fn sidebar_trait(buf: &mut Buffer, it: &clean::Item, t: &clean::Trait) {
         );
     }
 
-    sidebar.push_str(&sidebar_assoc_items(it));
-
     write!(buf, "<div class=\"block items\">{}</div>", sidebar)
 }
 
diff --git a/src/libstd/panicking.rs b/src/libstd/panicking.rs
index 6a120f930ab..d22ac1d5385 100644
--- a/src/libstd/panicking.rs
+++ b/src/libstd/panicking.rs
@@ -201,8 +201,7 @@ fn default_hook(info: &PanicInfo<'_>) {
                 if FIRST_PANIC.swap(false, Ordering::SeqCst) {
                     let _ = writeln!(
                         err,
-                        "note: run with `RUST_BACKTRACE=1` \
-                                           environment variable to display a backtrace"
+                        "note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace"
                     );
                 }
             }
@@ -454,10 +453,7 @@ fn rust_panic_with_hook(
     // process real quickly as we don't want to try calling it again as it'll
     // probably just panic again.
     if panics > 2 {
-        util::dumb_print(format_args!(
-            "thread panicked while processing \
-                                       panic. aborting.\n"
-        ));
+        util::dumb_print(format_args!("thread panicked while processing panic. aborting.\n"));
         intrinsics::abort()
     }
 
@@ -489,10 +485,7 @@ fn rust_panic_with_hook(
         // have limited options. Currently our preference is to
         // just abort. In the future we may consider resuming
         // unwinding or otherwise exiting the thread cleanly.
-        util::dumb_print(format_args!(
-            "thread panicked while panicking. \
-                                       aborting.\n"
-        ));
+        util::dumb_print(format_args!("thread panicked while panicking. aborting.\n"));
         intrinsics::abort()
     }
 
diff --git a/src/libstd/sys/hermit/net.rs b/src/libstd/sys/hermit/net.rs
index 9e588c4265a..8a788a9265f 100644
--- a/src/libstd/sys/hermit/net.rs
+++ b/src/libstd/sys/hermit/net.rs
@@ -147,10 +147,7 @@ impl TcpStream {
             .map_err(|_| io::Error::new(ErrorKind::Other, "peer_addr failed"))?;
 
         let saddr = match ipaddr {
-            Ipv4(ref addr) => SocketAddr::new(
-                IpAddr::V4(Ipv4Addr::new(addr.0[0], addr.0[1], addr.0[2], addr.0[3])),
-                port,
-            ),
+            Ipv4(ref addr) => SocketAddr::new(IpAddr::V4(Ipv4Addr::from(addr.0)), port),
             Ipv6(ref addr) => SocketAddr::new(IpAddr::V6(Ipv6Addr::from(addr.0)), port),
             _ => {
                 return Err(io::Error::new(ErrorKind::Other, "peer_addr failed"));
@@ -227,10 +224,7 @@ impl TcpListener {
         let (handle, ipaddr, port) = abi::tcplistener::accept(self.0.port())
             .map_err(|_| io::Error::new(ErrorKind::Other, "accept failed"))?;
         let saddr = match ipaddr {
-            Ipv4(ref addr) => SocketAddr::new(
-                IpAddr::V4(Ipv4Addr::new(addr.0[0], addr.0[1], addr.0[2], addr.0[3])),
-                port,
-            ),
+            Ipv4(ref addr) => SocketAddr::new(IpAddr::V4(Ipv4Addr::from(addr.0)), port),
             Ipv6(ref addr) => SocketAddr::new(IpAddr::V6(Ipv6Addr::from(addr.0)), port),
             _ => {
                 return Err(io::Error::new(ErrorKind::Other, "accept failed"));