Auto merge of #73550 - RalfJung:rollup-5huj1k1, r=RalfJung

Rollup of 9 pull requests

Successful merges:

 - #72600 (Properly encode AnonConst into crate metadata)
 - #73055 (remove leftover mentions of `skol` and `int` from the compiler)
 - #73058 (Support sanitizers on aarch64-unknown-linux-gnu)
 - #73171 (RISC-V Emulated Testing)
 - #73404 (Update CFGuard syntax)
 - #73444 (ci: disable alt build during try builds)
 - #73471 (Prevent attacker from manipulating FPU tag word used in SGX enclave)
 - #73539 (Deprecate `Vec::remove_item`)
 - #73543 (Clean up E0695 explanation)

Failed merges:

r? @ghost

.github/workflows/ci.yml

@@ -152,10 +152,6 @@ jobs:
           - name: dist-x86_64-linux
             os: ubuntu-latest-xl
             env: {}
-          - name: dist-x86_64-linux-alt
-            env:
-              IMAGE: dist-x86_64-linux
-            os: ubuntu-latest-xl
     timeout-minutes: 600
     runs-on: "${{ matrix.os }}"
     steps:

src/bootstrap/builder.rs

@@ -1206,7 +1206,7 @@ impl<'a> Builder<'a> {
             );
         }
 
-        // If Control Flow Guard is enabled, pass the `control_flow_guard=checks` flag to rustc
+        // If Control Flow Guard is enabled, pass the `control-flow-guard` flag to rustc
         // when compiling the standard library, since this might be linked into the final outputs
         // produced by rustc. Since this mitigation is only available on Windows, only enable it
         // for the standard library in case the compiler is run on a non-Windows platform.
@@ -1217,7 +1217,7 @@ impl<'a> Builder<'a> {
             && self.config.control_flow_guard
             && compiler.stage >= 1
         {
-            rustflags.arg("-Zcontrol_flow_guard=checks");
+            rustflags.arg("-Zcontrol-flow-guard");
         }
 
         // For `cargo doc` invocations, make rustdoc print the Rust version into the docs

src/bootstrap/configure.py

@@ -141,6 +141,8 @@ v("qemu-armhf-rootfs", "target.arm-unknown-linux-gnueabihf.qemu-rootfs",
   "rootfs in qemu testing, you probably don't want to use this")
 v("qemu-aarch64-rootfs", "target.aarch64-unknown-linux-gnu.qemu-rootfs",
   "rootfs in qemu testing, you probably don't want to use this")
+v("qemu-riscv64-rootfs", "target.riscv64gc-unknown-linux-gnu.qemu-rootfs",
+  "rootfs in qemu testing, you probably don't want to use this")
 v("experimental-targets", "llvm.experimental-targets",
   "experimental LLVM targets to build")
 v("release-channel", "rust.channel", "the name of the release channel to build")

src/bootstrap/native.rs

@@ -689,48 +689,41 @@ fn supported_sanitizers(
     target: Interned<String>,
     channel: &str,
 ) -> Vec<SanitizerRuntime> {
-    let mut result = Vec::new();
+    let darwin_libs = |os: &str, components: &[&str]| -> Vec<SanitizerRuntime> {
+        components
+            .into_iter()
+            .map(move |c| SanitizerRuntime {
+                cmake_target: format!("clang_rt.{}_{}_dynamic", c, os),
+                path: out_dir
+                    .join(&format!("build/lib/darwin/libclang_rt.{}_{}_dynamic.dylib", c, os)),
+                name: format!("librustc-{}_rt.{}.dylib", channel, c),
+            })
+            .collect()
+    };
+
+    let common_libs = |os: &str, arch: &str, components: &[&str]| -> Vec<SanitizerRuntime> {
+        components
+            .into_iter()
+            .map(move |c| SanitizerRuntime {
+                cmake_target: format!("clang_rt.{}-{}", c, arch),
+                path: out_dir.join(&format!("build/lib/{}/libclang_rt.{}-{}.a", os, c, arch)),
+                name: format!("librustc-{}_rt.{}.a", channel, c),
+            })
+            .collect()
+    };
+
     match &*target {
-        "x86_64-apple-darwin" => {
+        "aarch64-fuchsia" => common_libs("fuchsia", "aarch64", &["asan"]),
-            for s in &["asan", "lsan", "tsan"] {
+        "aarch64-unknown-linux-gnu" => {
-                result.push(SanitizerRuntime {
+            common_libs("linux", "aarch64", &["asan", "lsan", "msan", "tsan"])
-                    cmake_target: format!("clang_rt.{}_osx_dynamic", s),
-                    path: out_dir
-                        .join(&format!("build/lib/darwin/libclang_rt.{}_osx_dynamic.dylib", s)),
-                    name: format!("librustc-{}_rt.{}.dylib", channel, s),
-                });
-            }
         }
+        "x86_64-apple-darwin" => darwin_libs("osx", &["asan", "lsan", "tsan"]),
+        "x86_64-fuchsia" => common_libs("fuchsia", "x86_64", &["asan"]),
         "x86_64-unknown-linux-gnu" => {
-            for s in &["asan", "lsan", "msan", "tsan"] {
+            common_libs("linux", "x86_64", &["asan", "lsan", "msan", "tsan"])
-                result.push(SanitizerRuntime {
-                    cmake_target: format!("clang_rt.{}-x86_64", s),
-                    path: out_dir.join(&format!("build/lib/linux/libclang_rt.{}-x86_64.a", s)),
-                    name: format!("librustc-{}_rt.{}.a", channel, s),
-                });
-            }
         }
-        "x86_64-fuchsia" => {
+        _ => Vec::new(),
-            for s in &["asan"] {
-                result.push(SanitizerRuntime {
-                    cmake_target: format!("clang_rt.{}-x86_64", s),
-                    path: out_dir.join(&format!("build/lib/fuchsia/libclang_rt.{}-x86_64.a", s)),
-                    name: format!("librustc-{}_rt.{}.a", channel, s),
-                });
-            }
-        }
-        "aarch64-fuchsia" => {
-            for s in &["asan"] {
-                result.push(SanitizerRuntime {
-                    cmake_target: format!("clang_rt.{}-aarch64", s),
-                    path: out_dir.join(&format!("build/lib/fuchsia/libclang_rt.{}-aarch64.a", s)),
-                    name: format!("librustc-{}_rt.{}.a", channel, s),
-                });
-            }
-        }
-        _ => {}
     }
-    result
 }
 
 struct HashStamp {

src/ci/azure-pipelines/try.yml

@@ -26,8 +26,6 @@ jobs:
   strategy:
     matrix:
       dist-x86_64-linux: {}
-      dist-x86_64-linux-alt:
-        IMAGE: dist-x86_64-linux
 
 # The macOS and Windows builds here are currently disabled due to them not being
 # overly necessary on `try` builds. We also don't actually have anything that

src/ci/docker/disabled/riscv64gc-linux/0001-Remove-stime-function-calls.patch

@@ -0,0 +1,96 @@
+From c820da85c65c7f3aa9e9cb3ed71ada69bf9b783e Mon Sep 17 00:00:00 2001
+From: Alistair Francis <alistair.francis@wdc.com>
+Date: Tue, 19 Nov 2019 13:06:40 +0100
+Subject: [PATCH] Remove stime() function calls
+
+stime() has been deprecated in glibc 2.31 and replaced with
+clock_settime(). Let's replace the stime() function calls with
+clock_settime() in preperation.
+
+function                                             old     new   delta
+rdate_main                                           197     224     +27
+clock_settime                                          -      27     +27
+date_main                                            926     941     +15
+stime                                                 37       -     -37
+------------------------------------------------------------------------------
+(add/remove: 2/2 grow/shrink: 2/0 up/down: 69/-37)             Total: 32 bytes
+
+Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
+Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
+
+[Tom Eccles: adjust patch context to apply on top of 1.31.1-stable]
+Signed-off-by: Tom Eccles <tom.eccles@codethink.co.uk>
+---
+ coreutils/date.c         | 6 +++++-
+ libbb/missing_syscalls.c | 8 --------
+ util-linux/rdate.c       | 8 ++++++--
+ 3 files changed, 11 insertions(+), 11 deletions(-)
+
+diff --git a/coreutils/date.c b/coreutils/date.c
+index 3414d38ae..4ade6abb4 100644
+--- a/coreutils/date.c
++++ b/coreutils/date.c
+@@ -279,6 +279,9 @@ int date_main(int argc UNUSED_PARAM, char **argv)
+ 		time(&ts.tv_sec);
+ #endif
+ 	}
++#if !ENABLE_FEATURE_DATE_NANO
++	ts.tv_nsec = 0;
++#endif
+ 	localtime_r(&ts.tv_sec, &tm_time);
+ 
+ 	/* If date string is given, update tm_time, and maybe set date */
+@@ -301,9 +304,10 @@ int date_main(int argc UNUSED_PARAM, char **argv)
+ 		if (date_str[0] != '@')
+ 			tm_time.tm_isdst = -1;
+ 		ts.tv_sec = validate_tm_time(date_str, &tm_time);
++		ts.tv_nsec = 0;
+ 
+ 		/* if setting time, set it */
+-		if ((opt & OPT_SET) && stime(&ts.tv_sec) < 0) {
++		if ((opt & OPT_SET) && clock_settime(CLOCK_REALTIME, &ts) < 0) {
+ 			bb_perror_msg("can't set date");
+ 		}
+ 	}
+diff --git a/libbb/missing_syscalls.c b/libbb/missing_syscalls.c
+index 87cf59b3d..dc40d9155 100644
+--- a/libbb/missing_syscalls.c
++++ b/libbb/missing_syscalls.c
+@@ -15,14 +15,6 @@ pid_t getsid(pid_t pid)
+ 	return syscall(__NR_getsid, pid);
+ }
+ 
+-int stime(const time_t *t)
+-{
+-	struct timeval tv;
+-	tv.tv_sec = *t;
+-	tv.tv_usec = 0;
+-	return settimeofday(&tv, NULL);
+-}
+-
+ int sethostname(const char *name, size_t len)
+ {
+ 	return syscall(__NR_sethostname, name, len);
+diff --git a/util-linux/rdate.c b/util-linux/rdate.c
+index 70f829e7f..878375d78 100644
+--- a/util-linux/rdate.c
++++ b/util-linux/rdate.c
+@@ -95,9 +95,13 @@ int rdate_main(int argc UNUSED_PARAM, char **argv)
+ 	if (!(flags & 2)) { /* no -p (-s may be present) */
+ 		if (time(NULL) == remote_time)
+ 			bb_error_msg("current time matches remote time");
+-		else
+-			if (stime(&remote_time) < 0)
++		else {
++			struct timespec ts;
++			ts.tv_sec = remote_time;
++			ts.tv_nsec = 0;
++			if (clock_settime(CLOCK_REALTIME, &ts) < 0)
+ 				bb_perror_msg_and_die("can't set time of day");
++		}
+ 	}
+ 
+ 	if (flags != 1) /* not lone -s */
+-- 
+2.25.1
+

src/ci/docker/disabled/riscv64gc-linux/Dockerfile

@@ -0,0 +1,102 @@
+# based on armhf-gnu/Dockerfile
+FROM ubuntu:20.04
+
+RUN echo 'debconf debconf/frontend select Noninteractive' | debconf-set-selections
+RUN apt-get update -y && apt-get install -y --no-install-recommends \
+    bc \
+    bison \
+    ca-certificates \
+    cmake \
+    cpio \
+    curl \
+    debian-ports-archive-keyring \
+    debootstrap \
+    flex \
+    gcc \
+    gcc-riscv64-linux-gnu \
+    git \
+    g++-riscv64-linux-gnu \
+    g++ \
+    libc6-dev \
+    libc6-dev-riscv64-cross \
+    make \
+    patch \
+    python3 \
+    qemu-system-misc \
+    xz-utils
+
+ENV ARCH=riscv
+ENV CROSS_COMPILE=riscv64-linux-gnu-
+
+WORKDIR /build
+
+# From https://github.com/michaeljclark/busybear-linux/blob/master/conf/linux.config
+COPY riscv64gc-linux/linux.config /build
+
+# Compile the kernel that we're going to be emulating with. This is
+# basically just done to be compatible with the QEMU target that we're going
+# to be using when running tests.
+RUN curl https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.6.16.tar.xz | tar xJf - && \
+    cp linux.config linux-5.6.16/.config && \
+    cd /build/linux-5.6.16 && \
+    make olddefconfig && \
+    make -j$(nproc) vmlinux
+RUN cp linux-5.6.16/vmlinux /tmp
+RUN rm -rf linux-5.6.16
+
+# Compile an instance of busybox as this provides a lightweight system and init
+# binary which we will boot into. Only trick here is configuring busybox to
+# build static binaries.
+RUN curl https://busybox.net/downloads/busybox-1.31.1.tar.bz2 | tar xjf -
+COPY riscv64gc-linux/0001-Remove-stime-function-calls.patch /build/busybox-1.31.1/
+RUN cd /build/busybox-1.31.1 && \
+    patch -p1 -i 0001-Remove-stime-function-calls.patch && \
+    make defconfig && \
+    sed -i 's/.*CONFIG_STATIC.*/CONFIG_STATIC=y/' .config && \
+    make -j$(nproc) && \
+    make install && \
+    mv _install /tmp/rootfs && \
+    cd /build && \
+    rm -rf busybox-1.31.1
+
+# Download the ubuntu rootfs, which we'll use as a chroot for all our tests
+# This is only needed to provide /lib/* and /usr/lib/*
+WORKDIR /tmp
+RUN debootstrap --variant=minbase --arch=riscv64 --foreign focal /tmp/rootfs/ubuntu
+RUN cd rootfs && mkdir proc sys dev etc etc/init.d
+# rootfs/ubuntu/proc is in a weird state (access fails with ELOOP) until
+# rootfs/ubuntu/debootstrap/debootstrap --second-stage is run (under emulation),
+# but this takes ages. Instead hack it into a good enough state.
+# /proc is used by std::env::current_exe() (which is roughly
+# `readlink /proc/self/exe`)
+RUN cd rootfs/ubuntu && rm -rf proc && mkdir proc
+
+# Copy over our init script, which starts up our test server and also a few other
+# misc tasks
+COPY scripts/qemu-bare-bones-rcS rootfs/etc/init.d/rcS
+RUN chmod +x rootfs/etc/init.d/rcS
+
+# Helper to quickly fill the entropy pool in the kernel
+COPY scripts/qemu-bare-bones-addentropy.c /tmp/addentropy.c
+RUN riscv64-linux-gnu-gcc addentropy.c -o rootfs/addentropy -static
+
+# download and build the riscv bootloader
+RUN git clone https://github.com/riscv/riscv-pk
+WORKDIR /tmp/riscv-pk
+# nothing special about this revision: it is just master at the time of writing
+# v1.0.0 doesn't build
+RUN git checkout 5d9ed238e1cabfbca3c47f50d32894ce94bfc304
+RUN mkdir build && cd build && \
+    ../configure --with-payload=/tmp/vmlinux --host=riscv64-linux-gnu && \
+    make -j$(nproc) && \
+    cp bbl /tmp
+WORKDIR /tmp
+RUN rm -rf /tmp/riscv-pk
+
+COPY scripts/sccache.sh /scripts/
+RUN sh /scripts/sccache.sh
+
+ENV RUST_CONFIGURE_ARGS --qemu-riscv64-rootfs=/tmp/rootfs
+ENV SCRIPT python3 ../x.py test --target riscv64gc-unknown-linux-gnu
+
+ENV NO_CHANGE_USER=1

src/ci/docker/disabled/riscv64gc-linux/linux.config

@@ -0,0 +1,51 @@
+CONFIG_DEFAULT_HOSTNAME="busybear"
+CONFIG_SYSVIPC=y
+CONFIG_POSIX_MQUEUE=y
+CONFIG_IKCONFIG=y
+CONFIG_IKCONFIG_PROC=y
+CONFIG_CGROUPS=y
+CONFIG_CGROUP_SCHED=y
+CONFIG_CFS_BANDWIDTH=y
+CONFIG_CGROUP_BPF=y
+CONFIG_NAMESPACES=y
+CONFIG_USER_NS=y
+CONFIG_CHECKPOINT_RESTORE=y
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_EXPERT=y
+CONFIG_BPF_SYSCALL=y
+CONFIG_SMP=y
+CONFIG_MODULES=y
+CONFIG_NET=y
+CONFIG_PACKET=y
+CONFIG_PACKET_DIAG=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_NETLINK_DIAG=y
+# CONFIG_WIRELESS is not set
+CONFIG_PCI=y
+CONFIG_DEVTMPFS=y
+CONFIG_BLK_DEV_LOOP=y
+CONFIG_VIRTIO_BLK=y
+CONFIG_NETDEVICES=y
+CONFIG_VIRTIO_NET=y
+# CONFIG_ETHERNET is not set
+# CONFIG_WLAN is not set
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_HVC_RISCV_SBI=y
+# CONFIG_HW_RANDOM is not set
+# CONFIG_USB_SUPPORT is not set
+CONFIG_VIRTIO_MMIO=y
+CONFIG_SIFIVE_PLIC=y
+CONFIG_RAS=y
+CONFIG_EXT2_FS=y
+CONFIG_EXT3_FS=y
+CONFIG_EXT4_FS_POSIX_ACL=y
+CONFIG_AUTOFS4_FS=y
+CONFIG_MSDOS_FS=y
+CONFIG_VFAT_FS=y
+CONFIG_TMPFS=y
+# CONFIG_CRYPTO_ECHAINIV is not set
+# CONFIG_CRYPTO_HW is not set
+CONFIG_PRINTK_TIME=y

src/ci/docker/dist-aarch64-linux/Dockerfile

@@ -35,5 +35,6 @@ ENV HOSTS=aarch64-unknown-linux-gnu
 ENV RUST_CONFIGURE_ARGS \
       --enable-full-tools \
       --enable-profiler \
+      --enable-sanitizers \
       --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/github-actions/ci.yml

@@ -281,11 +281,6 @@ jobs:
           - name: dist-x86_64-linux
             <<: *job-linux-xl
 
-          - name: dist-x86_64-linux-alt
-            env:
-              IMAGE: dist-x86_64-linux
-            <<: *job-linux-xl
-
   auto:
     <<: *base-ci-job
     name: auto

src/doc/unstable-book/src/compiler-flags/control-flow-guard.md

@@ -1,10 +1,10 @@
-# `control_flow_guard`
+# `control-flow-guard`
 
 The tracking issue for this feature is: [#68793](https://github.com/rust-lang/rust/issues/68793).
 
 ------------------------
 
-The rustc flag `-Z control_flow_guard=checks` enables the Windows [Control Flow Guard](https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard) (CFG) platform security feature.
+The rustc flag `-Z control-flow-guard` enables the Windows [Control Flow Guard](https://docs.microsoft.com/en-us/windows/win32/secbp/control-flow-guard) (CFG) platform security feature.
 
 CFG is an exploit mitigation designed to enforce control-flow integrity for software running on supported Windows platforms (Windows 8.1 onwards). Specifically, CFG uses runtime checks to validate the target address of every indirect call/jump before allowing the call to complete. 
 
@@ -29,7 +29,7 @@ The CFG checks and metadata can potentially increase binary size and runtime ove
 
 ## Testing Control Flow Guard
 
-The rustc flag `-Z control_flow_guard=nochecks` instructs LLVM to emit the list of valid call targets without inserting runtime checks. This flag should only be used for testing purposes as it does not provide security enforcement.
+The rustc flag `-Z control-flow-guard=nochecks` instructs LLVM to emit the list of valid call targets without inserting runtime checks. This flag should only be used for testing purposes as it does not provide security enforcement.
 
 
 ## Control Flow Guard in libraries
@@ -44,14 +44,14 @@ For example:
 ```cmd
 rustup toolchain install --force nightly
 rustup component add rust-src
-SET RUSTFLAGS=-Z control_flow_guard=checks
+SET RUSTFLAGS=-Z control-flow-guard
 cargo +nightly build -Z build-std --target x86_64-pc-windows-msvc
 ```
 
 ```PowerShell
 rustup toolchain install --force nightly
 rustup component add rust-src
-$Env:RUSTFLAGS = "-Z control_flow_guard=checks"
+$Env:RUSTFLAGS = "-Z control-flow-guard"
 cargo +nightly build -Z build-std --target x86_64-pc-windows-msvc
 ```
 

src/liballoc/tests/lib.rs

@@ -12,7 +12,6 @@
 #![feature(associated_type_bounds)]
 #![feature(binary_heap_into_iter_sorted)]
 #![feature(binary_heap_drain_sorted)]
-#![feature(vec_remove_item)]
 #![feature(split_inclusive)]
 #![feature(binary_heap_retain)]
 

src/liballoc/tests/vec.rs

@@ -131,21 +131,6 @@ fn test_extend_ref() {
     assert_eq!(v, [1, 2, 3, 4, 5, 6, 7]);
 }
 
-#[test]
-fn test_remove_item() {
-    let mut v = vec![1, 2, 3];
-    v.remove_item(&1);
-
-    assert_eq!(v.len(), 2);
-    assert_eq!(v, [2, 3]);
-
-    let mut w = vec![1, 2, 3];
-    w.remove_item(&4);
-
-    assert_eq!(w.len(), 3);
-    w.remove_item(&4);
-}
-
 #[test]
 fn test_slice_from_mut() {
     let mut values = vec![1, 2, 3, 4, 5];

src/liballoc/vec.rs

@@ -1760,17 +1760,15 @@ impl<T: PartialEq> Vec<T> {
 impl<T> Vec<T> {
     /// Removes the first instance of `item` from the vector if the item exists.
     ///
-    /// # Examples
+    /// This method will be removed soon.
-    ///
-    /// ```
-    /// # #![feature(vec_remove_item)]
-    /// let mut vec = vec![1, 2, 3, 1];
-    ///
-    /// vec.remove_item(&1);
-    ///
-    /// assert_eq!(vec, vec![2, 3, 1]);
-    /// ```
     #[unstable(feature = "vec_remove_item", reason = "recently added", issue = "40062")]
+    #[rustc_deprecated(
+        reason = "Removing the first item equal to a needle is already easily possible \
+            with iterators and the current Vec methods. Furthermore, having a method for \
+            one particular case of removal (linear search, only the first item, no swap remove) \
+            but not for others is inconsistent. This method will be removed soon.",
+        since = "1.46.0"
+    )]
     pub fn remove_item<V>(&mut self, item: &V) -> Option<T>
     where
         T: PartialEq<V>,

src/librustc_codegen_ssa/back/link.rs

@@ -804,7 +804,10 @@ fn link_sanitizer_runtime(sess: &Session, linker: &mut dyn Linker, name: &str) {
             linker.args(&["-Wl,-rpath", "-Xlinker", rpath]);
             linker.link_dylib(Symbol::intern(&libname));
         }
-        "x86_64-unknown-linux-gnu" | "x86_64-fuchsia" | "aarch64-fuchsia" => {
+        "aarch64-fuchsia"
+        | "aarch64-unknown-linux-gnu"
+        | "x86_64-fuchsia"
+        | "x86_64-unknown-linux-gnu" => {
             let filename = format!("librustc{}_rt.{}.a", channel, name);
             let path = default_tlib.join(&filename);
             linker.link_whole_rlib(&path);

src/librustc_error_codes/error_codes/E0695.md

@@ -1,6 +1,6 @@
 A `break` statement without a label appeared inside a labeled block.
 
-Example of erroneous code:
+Erroneous code example:
 
 ```compile_fail,E0695
 # #![feature(label_break_value)]

src/librustc_infer/infer/higher_ranked/mod.rs

@@ -63,14 +63,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     /// placeholder region. This is the first step of checking subtyping
     /// when higher-ranked things are involved.
     ///
-    /// **Important:** you must call this function from within a snapshot.
+    /// **Important:** You have to be careful to not leak these placeholders,
-    /// Moreover, before committing the snapshot, you must eventually call
+    /// for more information about how placeholders and HRTBs work, see
-    /// either `plug_leaks` or `pop_placeholders` to remove the placeholder
-    /// regions. If you rollback the snapshot (or are using a probe), then
-    /// the pop occurs as part of the rollback, so an explicit call is not
-    /// needed (but is also permitted).
-    ///
-    /// For more information about how placeholders and HRTBs work, see
     /// the [rustc dev guide].
     ///
     /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html

src/librustc_infer/infer/region_constraints/leak_check.rs

@@ -128,7 +128,7 @@ impl<'tcx> TaintSet<'tcx> {
                         verifys[i].origin.span(),
                         "we never add verifications while doing higher-ranked things",
                     ),
-                    &Purged | &AddCombination(..) | &AddVar(..) => {}
+                    &AddCombination(..) | &AddVar(..) => {}
                 }
             }
         }

src/librustc_infer/infer/region_constraints/mod.rs

@@ -289,14 +289,6 @@ pub(crate) enum UndoLog<'tcx> {
 
     /// We added a GLB/LUB "combination variable".
     AddCombination(CombineMapType, TwoRegions<'tcx>),
-
-    /// During skolemization, we sometimes purge entries from the undo
-    /// log in a kind of minisnapshot (unlike other snapshots, this
-    /// purging actually takes place *on success*). In that case, we
-    /// replace the corresponding entry with `Noop` so as to avoid the
-    /// need to do a bunch of swapping. (We can't use `swap_remove` as
-    /// the order of the vector is important.)
-    Purged,
 }
 
 #[derive(Copy, Clone, PartialEq)]
@@ -357,9 +349,6 @@ impl<'tcx> RegionConstraintStorage<'tcx> {
 
     fn rollback_undo_entry(&mut self, undo_entry: UndoLog<'tcx>) {
         match undo_entry {
-            Purged => {
-                // nothing to do here
-            }
             AddVar(vid) => {
                 self.var_infos.pop().unwrap();
                 assert_eq!(self.var_infos.len(), vid.index() as usize);
@@ -488,62 +477,6 @@ impl<'tcx> RegionConstraintCollector<'_, 'tcx> {
         self.var_infos[vid].origin
     }
 
-    /// Removes all the edges to/from the placeholder regions that are
-    /// in `skols`. This is used after a higher-ranked operation
-    /// completes to remove all trace of the placeholder regions
-    /// created in that time.
-    pub fn pop_placeholders(&mut self, placeholders: &FxHashSet<ty::Region<'tcx>>) {
-        debug!("pop_placeholders(placeholders={:?})", placeholders);
-
-        assert!(UndoLogs::<super::UndoLog<'_>>::in_snapshot(&self.undo_log));
-
-        let constraints_to_kill: Vec<usize> = self
-            .undo_log
-            .iter()
-            .enumerate()
-            .rev()
-            .filter(|&(_, undo_entry)| match undo_entry {
-                super::UndoLog::RegionConstraintCollector(undo_entry) => {
-                    kill_constraint(placeholders, undo_entry)
-                }
-                _ => false,
-            })
-            .map(|(index, _)| index)
-            .collect();
-
-        for index in constraints_to_kill {
-            let undo_entry = match &mut self.undo_log[index] {
-                super::UndoLog::RegionConstraintCollector(undo_entry) => {
-                    mem::replace(undo_entry, Purged)
-                }
-                _ => unreachable!(),
-            };
-            self.rollback_undo_entry(undo_entry);
-        }
-
-        return;
-
-        fn kill_constraint<'tcx>(
-            placeholders: &FxHashSet<ty::Region<'tcx>>,
-            undo_entry: &UndoLog<'tcx>,
-        ) -> bool {
-            match undo_entry {
-                &AddConstraint(Constraint::VarSubVar(..)) => false,
-                &AddConstraint(Constraint::RegSubVar(a, _)) => placeholders.contains(&a),
-                &AddConstraint(Constraint::VarSubReg(_, b)) => placeholders.contains(&b),
-                &AddConstraint(Constraint::RegSubReg(a, b)) => {
-                    placeholders.contains(&a) || placeholders.contains(&b)
-                }
-                &AddGiven(..) => false,
-                &AddVerify(_) => false,
-                &AddCombination(_, ref two_regions) => {
-                    placeholders.contains(&two_regions.a) || placeholders.contains(&two_regions.b)
-                }
-                &AddVar(..) | &Purged => false,
-            }
-        }
-    }
-
     fn add_constraint(&mut self, constraint: Constraint<'tcx>, origin: SubregionOrigin<'tcx>) {
         // cannot add constraints once regions are resolved
         debug!("RegionConstraintCollector: add_constraint({:?})", constraint);

src/librustc_infer/infer/undo_log.rs

@@ -198,10 +198,6 @@ impl<'tcx> InferCtxtUndoLogs<'tcx> {
         assert!(self.logs.len() >= snapshot.undo_len);
         assert!(self.num_open_snapshots > 0);
     }
-
-    pub(crate) fn iter(&self) -> std::slice::Iter<'_, UndoLog<'tcx>> {
-        self.logs.iter()
-    }
 }
 
 impl<'tcx> std::ops::Index<usize> for InferCtxtUndoLogs<'tcx> {

src/librustc_infer/traits/mod.rs

@@ -29,10 +29,10 @@ crate use self::util::elaborate_predicates;
 
 pub use rustc_middle::traits::*;
 
-/// An `Obligation` represents some trait reference (e.g., `int: Eq`) for
+/// An `Obligation` represents some trait reference (e.g., `i32: Eq`) for
 /// which the "impl_source" must be found. The process of finding a "impl_source" is
 /// called "resolving" the `Obligation`. This process consists of
-/// either identifying an `impl` (e.g., `impl Eq for int`) that
+/// either identifying an `impl` (e.g., `impl Eq for i32`) that
 /// satisfies the obligation, or else finding a bound that is in
 /// scope. The eventual result is usually a `Selection` (defined below).
 #[derive(Clone, PartialEq, Eq, Hash)]

src/librustc_infer/traits/util.rs

@@ -63,11 +63,11 @@ impl PredicateSet<'tcx> {
     fn insert(&mut self, pred: ty::Predicate<'tcx>) -> bool {
         // We have to be careful here because we want
         //
-        //    for<'a> Foo<&'a int>
+        //    for<'a> Foo<&'a i32>
         //
         // and
         //
-        //    for<'b> Foo<&'b int>
+        //    for<'b> Foo<&'b i32>
         //
         // to be considered equivalent. So normalize all late-bound
         // regions before we throw things into the underlying set.

src/librustc_interface/tests.rs

@@ -465,7 +465,6 @@ fn test_debugging_options_tracking_hash() {
     untracked!(ast_json_noexpand, true);
     untracked!(borrowck, String::from("other"));
     untracked!(borrowck_stats, true);
-    untracked!(control_flow_guard, CFGuard::Checks);
     untracked!(deduplicate_diagnostics, true);
     untracked!(dep_tasks, true);
     untracked!(dont_buffer_diagnostics, true);
@@ -539,6 +538,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(binary_dep_depinfo, true);
     tracked!(chalk, true);
     tracked!(codegen_backend, Some("abc".to_string()));
+    tracked!(control_flow_guard, CFGuard::Checks);
     tracked!(crate_attr, vec!["abc".to_string()]);
     tracked!(debug_macros, true);
     tracked!(dep_info_omit_d_target, true);

src/librustc_metadata/rmeta/decoder.rs

@@ -565,6 +565,7 @@ impl MetadataBlob {
 impl EntryKind {
     fn def_kind(&self) -> DefKind {
         match *self {
+            EntryKind::AnonConst(..) => DefKind::AnonConst,
             EntryKind::Const(..) => DefKind::Const,
             EntryKind::AssocConst(..) => DefKind::AssocConst,
             EntryKind::ImmStatic
@@ -1121,7 +1122,8 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
 
     fn mir_const_qualif(&self, id: DefIndex) -> mir::ConstQualifs {
         match self.kind(id) {
-            EntryKind::Const(qualif, _)
+            EntryKind::AnonConst(qualif, _)
+            | EntryKind::Const(qualif, _)
             | EntryKind::AssocConst(
                 AssocContainer::ImplDefault
                 | AssocContainer::ImplFinal
@@ -1340,7 +1342,9 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
 
     fn get_rendered_const(&self, id: DefIndex) -> String {
         match self.kind(id) {
-            EntryKind::Const(_, data) | EntryKind::AssocConst(_, _, data) => data.decode(self).0,
+            EntryKind::AnonConst(_, data)
+            | EntryKind::Const(_, data)
+            | EntryKind::AssocConst(_, _, data) => data.decode(self).0,
             _ => bug!(),
         }
     }

src/librustc_metadata/rmeta/encoder.rs

@@ -1358,7 +1358,7 @@ impl EncodeContext<'tcx> {
         let const_data = self.encode_rendered_const_for_body(body_id);
         let qualifs = self.tcx.mir_const_qualif(def_id);
 
-        record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::Const(qualifs, const_data));
+        record!(self.tables.kind[def_id.to_def_id()] <- EntryKind::AnonConst(qualifs, const_data));
         record!(self.tables.visibility[def_id.to_def_id()] <- ty::Visibility::Public);
         record!(self.tables.span[def_id.to_def_id()] <- self.tcx.def_span(def_id));
         self.encode_item_type(def_id.to_def_id());

src/librustc_metadata/rmeta/mod.rs

@@ -281,6 +281,7 @@ define_tables! {
 
 #[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
 enum EntryKind {
+    AnonConst(mir::ConstQualifs, Lazy<RenderedConst>),
     Const(mir::ConstQualifs, Lazy<RenderedConst>),
     ImmStatic,
     MutStatic,

src/librustc_middle/lib.rs

@@ -45,7 +45,6 @@
 #![feature(min_specialization)]
 #![feature(track_caller)]
 #![feature(trusted_len)]
-#![feature(vec_remove_item)]
 #![feature(stmt_expr_attributes)]
 #![feature(test)]
 #![feature(in_band_lifetimes)]

src/librustc_middle/traits/mod.rs

@@ -393,23 +393,25 @@ pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>;
 /// ```
 /// impl<T:Clone> Clone<T> for Option<T> { ... } // Impl_1
 /// impl<T:Clone> Clone<T> for Box<T> { ... }    // Impl_2
-/// impl Clone for int { ... }             // Impl_3
+/// impl Clone for i32 { ... }                   // Impl_3
 ///
-/// fn foo<T:Clone>(concrete: Option<Box<int>>,
+/// fn foo<T: Clone>(concrete: Option<Box<i32>>, param: T, mixed: Option<T>) {
-///                 param: T,
+///     // Case A: Vtable points at a specific impl. Only possible when
-///                 mixed: Option<T>) {
+///     // type is concretely known. If the impl itself has bounded
+///     // type parameters, Vtable will carry resolutions for those as well:
+///     concrete.clone(); // Vtable(Impl_1, [Vtable(Impl_2, [Vtable(Impl_3)])])
 ///
-///    // Case A: ImplSource points at a specific impl. Only possible when
+///     // Case A: ImplSource points at a specific impl. Only possible when
-///    // type is concretely known. If the impl itself has bounded
+///     // type is concretely known. If the impl itself has bounded
-///    // type parameters, ImplSource will carry resolutions for those as well:
+///     // type parameters, ImplSource will carry resolutions for those as well:
-///    concrete.clone(); // ImplSource(Impl_1, [ImplSource(Impl_2, [ImplSource(Impl_3)])])
+///     concrete.clone(); // ImplSource(Impl_1, [ImplSource(Impl_2, [ImplSource(Impl_3)])])
 ///
-///    // Case B: ImplSource must be provided by caller. This applies when
+///     // Case B: ImplSource must be provided by caller. This applies when
-///    // type is a type parameter.
+///     // type is a type parameter.
-///    param.clone();    // ImplSourceParam
+///     param.clone();    // ImplSourceParam
 ///
-///    // Case C: A mix of cases A and B.
+///     // Case C: A mix of cases A and B.
-///    mixed.clone();    // ImplSource(Impl_1, [ImplSourceParam])
+///     mixed.clone();    // ImplSource(Impl_1, [ImplSourceParam])
 /// }
 /// ```
 ///

src/librustc_middle/ty/subst.rs

@@ -599,12 +599,12 @@ impl<'a, 'tcx> SubstFolder<'a, 'tcx> {
     ///
     /// ```
     /// type Func<A> = fn(A);
-    /// type MetaFunc = for<'a> fn(Func<&'a int>)
+    /// type MetaFunc = for<'a> fn(Func<&'a i32>)
     /// ```
     ///
     /// The type `MetaFunc`, when fully expanded, will be
     ///
-    ///     for<'a> fn(fn(&'a int))
+    ///     for<'a> fn(fn(&'a i32))
     ///             ^~ ^~ ^~~
     ///             |  |  |
     ///             |  |  DebruijnIndex of 2
@@ -613,7 +613,7 @@ impl<'a, 'tcx> SubstFolder<'a, 'tcx> {
     /// Here the `'a` lifetime is bound in the outer function, but appears as an argument of the
     /// inner one. Therefore, that appearance will have a DebruijnIndex of 2, because we must skip
     /// over the inner binder (remember that we count De Bruijn indices from 1). However, in the
-    /// definition of `MetaFunc`, the binder is not visible, so the type `&'a int` will have a
+    /// definition of `MetaFunc`, the binder is not visible, so the type `&'a i32` will have a
     /// De Bruijn index of 1. It's only during the substitution that we can see we must increase the
     /// depth by 1 to account for the binder that we passed through.
     ///
@@ -621,18 +621,18 @@ impl<'a, 'tcx> SubstFolder<'a, 'tcx> {
     ///
     /// ```
     /// type FuncTuple<A> = (A,fn(A));
-    /// type MetaFuncTuple = for<'a> fn(FuncTuple<&'a int>)
+    /// type MetaFuncTuple = for<'a> fn(FuncTuple<&'a i32>)
     /// ```
     ///
     /// Here the final type will be:
     ///
-    ///     for<'a> fn((&'a int, fn(&'a int)))
+    ///     for<'a> fn((&'a i32, fn(&'a i32)))
     ///                 ^~~         ^~~
     ///                 |           |
     ///          DebruijnIndex of 1 |
     ///                      DebruijnIndex of 2
     ///
-    /// As indicated in the diagram, here the same type `&'a int` is substituted once, but in the
+    /// As indicated in the diagram, here the same type `&'a i32` is substituted once, but in the
     /// first case we do not increase the De Bruijn index and in the second case we do. The reason
     /// is that only in the second case have we passed through a fn binder.
     fn shift_vars_through_binders<T: TypeFoldable<'tcx>>(&self, val: T) -> T {

src/librustc_middle/ty/walk.rs

@@ -22,13 +22,13 @@ impl<'tcx> TypeWalker<'tcx> {
     /// Skips the subtree corresponding to the last type
     /// returned by `next()`.
     ///
-    /// Example: Imagine you are walking `Foo<Bar<int>, usize>`.
+    /// Example: Imagine you are walking `Foo<Bar<i32>, usize>`.
     ///
     /// ```
     /// let mut iter: TypeWalker = ...;
     /// iter.next(); // yields Foo
-    /// iter.next(); // yields Bar<int>
+    /// iter.next(); // yields Bar<i32>
-    /// iter.skip_current_subtree(); // skips int
+    /// iter.skip_current_subtree(); // skips i32
     /// iter.next(); // yields usize
     /// ```
     pub fn skip_current_subtree(&mut self) {

src/librustc_query_system/lib.rs

@@ -6,7 +6,6 @@
 #![feature(hash_raw_entry)]
 #![feature(min_specialization)]
 #![feature(stmt_expr_attributes)]
-#![feature(vec_remove_item)]
 
 #[macro_use]
 extern crate log;

src/librustc_query_system/query/job.rs

@@ -452,7 +452,9 @@ fn remove_cycle<CTX: QueryContext>(
 
         // Remove the queries in our cycle from the list of jobs to look at
         for r in &stack {
-            jobs.remove_item(&r.1);
+            if let Some(pos) = jobs.iter().position(|j| j == &r.1) {
+                jobs.remove(pos);
+            }
         }
 
         // Find the queries in the cycle which are

src/librustc_session/config.rs

@@ -103,7 +103,7 @@ pub enum Strip {
     Symbols,
 }
 
-/// The different settings that the `-Z control_flow_guard` flag can have.
+/// The different settings that the `-Z control-flow-guard` flag can have.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum CFGuard {
     /// Do not emit Control Flow Guard metadata or checks.

src/librustc_session/options.rs

@@ -250,7 +250,8 @@ macro_rules! options {
         pub const parse_relro_level: &str = "one of: `full`, `partial`, or `off`";
         pub const parse_sanitizers: &str = "comma separated list of sanitizers: `address`, `leak`, `memory` or `thread`";
         pub const parse_sanitizer_memory_track_origins: &str = "0, 1, or 2";
-        pub const parse_cfguard: &str = "either `disabled`, `nochecks`, or `checks`";
+        pub const parse_cfguard: &str =
+            "either a boolean (`yes`, `no`, `on`, `off`, etc), `checks`, or `nochecks`";
         pub const parse_strip: &str = "either `none`, `debuginfo`, or `symbols`";
         pub const parse_linker_flavor: &str = ::rustc_target::spec::LinkerFlavor::one_of();
         pub const parse_optimization_fuel: &str = "crate=integer";
@@ -495,12 +496,24 @@ macro_rules! options {
         }
 
         fn parse_cfguard(slot: &mut CFGuard, v: Option<&str>) -> bool {
-            match v {
+            if v.is_some() {
-                Some("disabled") => *slot = CFGuard::Disabled,
+                let mut bool_arg = None;
-                Some("nochecks") => *slot = CFGuard::NoChecks,
+                if parse_opt_bool(&mut bool_arg, v) {
-                Some("checks") => *slot = CFGuard::Checks,
+                    *slot = if bool_arg.unwrap() {
-                _ => return false,
+                        CFGuard::Checks
+                    } else {
+                        CFGuard::Disabled
+                    };
+                    return true
+                }
             }
+
+            *slot = match v {
+                None => CFGuard::Checks,
+                Some("checks") => CFGuard::Checks,
+                Some("nochecks") => CFGuard::NoChecks,
+                Some(_) => return false,
+            };
             true
         }
 
@@ -796,8 +809,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "enable the experimental Chalk-based trait solving engine"),
     codegen_backend: Option<String> = (None, parse_opt_string, [TRACKED],
         "the backend to use"),
-    control_flow_guard: CFGuard = (CFGuard::Disabled, parse_cfguard, [UNTRACKED],
+    control_flow_guard: CFGuard = (CFGuard::Disabled, parse_cfguard, [TRACKED],
-        "use Windows Control Flow Guard (`disabled`, `nochecks` or `checks`)"),
+        "use Windows Control Flow Guard (default: no)"),
     crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],
         "inject the given attribute in the crate"),
     debug_macros: bool = (false, parse_bool, [TRACKED],

src/librustc_session/session.rs

@@ -1349,11 +1349,19 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
         );
     }
 
-    const ASAN_SUPPORTED_TARGETS: &[&str] =
+    const ASAN_SUPPORTED_TARGETS: &[&str] = &[
-        &["aarch64-fuchsia", "x86_64-apple-darwin", "x86_64-fuchsia", "x86_64-unknown-linux-gnu"];
+        "aarch64-fuchsia",
-    const LSAN_SUPPORTED_TARGETS: &[&str] = &["x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+        "aarch64-unknown-linux-gnu",
-    const MSAN_SUPPORTED_TARGETS: &[&str] = &["x86_64-unknown-linux-gnu"];
+        "x86_64-apple-darwin",
-    const TSAN_SUPPORTED_TARGETS: &[&str] = &["x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+        "x86_64-fuchsia",
+        "x86_64-unknown-linux-gnu",
+    ];
+    const LSAN_SUPPORTED_TARGETS: &[&str] =
+        &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+    const MSAN_SUPPORTED_TARGETS: &[&str] =
+        &["aarch64-unknown-linux-gnu", "x86_64-unknown-linux-gnu"];
+    const TSAN_SUPPORTED_TARGETS: &[&str] =
+        &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
 
     // Sanitizers can only be used on some tested platforms.
     for s in sess.opts.debugging_opts.sanitizer {

src/librustc_trait_selection/traits/project.rs

@@ -361,7 +361,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
                 // handle normalization within binders because
                 // otherwise we wind up a need to normalize when doing
                 // trait matching (since you can have a trait
-                // obligation like `for<'a> T::B : Fn(&'a int)`), but
+                // obligation like `for<'a> T::B: Fn(&'a i32)`), but
                 // we can't normalize with bound regions in scope. So
                 // far now we just ignore binders but only normalize
                 // if all bound regions are gone (and then we still

src/librustc_trait_selection/traits/query/normalize.rs

@@ -145,7 +145,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                 // handle normalization within binders because
                 // otherwise we wind up a need to normalize when doing
                 // trait matching (since you can have a trait
-                // obligation like `for<'a> T::B : Fn(&'a int)`), but
+                // obligation like `for<'a> T::B: Fn(&'a i32)`), but
                 // we can't normalize with bound regions in scope. So
                 // far now we just ignore binders but only normalize
                 // if all bound regions are gone (and then we still

src/librustc_trait_selection/traits/select/confirmation.rs

@@ -553,14 +553,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     ///
     /// Here is an example. Imagine we have a closure expression
     /// and we desugared it so that the type of the expression is
-    /// `Closure`, and `Closure` expects an int as argument. Then it
+    /// `Closure`, and `Closure` expects `i32` as argument. Then it
     /// is "as if" the compiler generated this impl:
     ///
-    ///     impl Fn(int) for Closure { ... }
+    ///     impl Fn(i32) for Closure { ... }
     ///
-    /// Now imagine our obligation is `Fn(usize) for Closure`. So far
+    /// Now imagine our obligation is `Closure: Fn(usize)`. So far
     /// we have matched the self type `Closure`. At this point we'll
-    /// compare the `int` to `usize` and generate an error.
+    /// compare the `i32` to `usize` and generate an error.
     ///
     /// Note that this checking occurs *after* the impl has selected,
     /// because these output type parameters should not affect the

src/librustc_trait_selection/traits/select/mod.rs

@@ -1754,27 +1754,26 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     ) -> Vec<PredicateObligation<'tcx>> {
         // Because the types were potentially derived from
         // higher-ranked obligations they may reference late-bound
-        // regions. For example, `for<'a> Foo<&'a int> : Copy` would
+        // regions. For example, `for<'a> Foo<&'a i32> : Copy` would
-        // yield a type like `for<'a> &'a int`. In general, we
+        // yield a type like `for<'a> &'a i32`. In general, we
         // maintain the invariant that we never manipulate bound
         // regions, so we have to process these bound regions somehow.
         //
         // The strategy is to:
         //
         // 1. Instantiate those regions to placeholder regions (e.g.,
-        //    `for<'a> &'a int` becomes `&0 int`.
+        //    `for<'a> &'a i32` becomes `&0 i32`.
-        // 2. Produce something like `&'0 int : Copy`
+        // 2. Produce something like `&'0 i32 : Copy`
-        // 3. Re-bind the regions back to `for<'a> &'a int : Copy`
+        // 3. Re-bind the regions back to `for<'a> &'a i32 : Copy`
 
         types
-            .skip_binder()
+            .skip_binder() // binder moved -\
             .iter()
             .flat_map(|ty| {
-                // binder moved -\
                 let ty: ty::Binder<Ty<'tcx>> = ty::Binder::bind(ty); // <----/
 
                 self.infcx.commit_unconditionally(|_| {
-                    let (skol_ty, _) = self.infcx.replace_bound_vars_with_placeholders(&ty);
+                    let (placeholder_ty, _) = self.infcx.replace_bound_vars_with_placeholders(&ty);
                     let Normalized { value: normalized_ty, mut obligations } =
                         ensure_sufficient_stack(|| {
                             project::normalize_with_depth(
@@ -1782,10 +1781,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                 param_env,
                                 cause.clone(),
                                 recursion_depth,
-                                &skol_ty,
+                                &placeholder_ty,
                             )
                         });
-                    let skol_obligation = predicate_for_trait_def(
+                    let placeholder_obligation = predicate_for_trait_def(
                         self.tcx(),
                         param_env,
                         cause.clone(),
@@ -1794,7 +1793,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                         normalized_ty,
                         &[],
                     );
-                    obligations.push(skol_obligation);
+                    obligations.push(placeholder_obligation);
                     obligations
                 })
             })
@@ -1844,9 +1843,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             return Err(());
         }
 
-        let (skol_obligation, placeholder_map) =
+        let (placeholder_obligation, placeholder_map) =
             self.infcx().replace_bound_vars_with_placeholders(&obligation.predicate);
-        let skol_obligation_trait_ref = skol_obligation.trait_ref;
+        let placeholder_obligation_trait_ref = placeholder_obligation.trait_ref;
 
         let impl_substs = self.infcx.fresh_substs_for_item(obligation.cause.span, impl_def_id);
 
@@ -1865,14 +1864,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         debug!(
             "match_impl(impl_def_id={:?}, obligation={:?}, \
-             impl_trait_ref={:?}, skol_obligation_trait_ref={:?})",
+             impl_trait_ref={:?}, placeholder_obligation_trait_ref={:?})",
-            impl_def_id, obligation, impl_trait_ref, skol_obligation_trait_ref
+            impl_def_id, obligation, impl_trait_ref, placeholder_obligation_trait_ref
         );
 
         let InferOk { obligations, .. } = self
             .infcx
             .at(&obligation.cause, obligation.param_env)
-            .eq(skol_obligation_trait_ref, impl_trait_ref)
+            .eq(placeholder_obligation_trait_ref, impl_trait_ref)
             .map_err(|e| debug!("match_impl: failed eq_trait_refs due to `{}`", e))?;
         nested_obligations.extend(obligations);
 

src/librustc_trait_selection/traits/specialize/mod.rs

@@ -130,7 +130,7 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId,
 
     // We determine whether there's a subset relationship by:
     //
-    // - skolemizing impl1,
+    // - replacing bound vars with placeholders in impl1,
     // - assuming the where clauses for impl1,
     // - instantiating impl2 with fresh inference variables,
     // - unifying,

src/librustc_typeck/astconv.rs

@@ -1394,13 +1394,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             // That is, consider this case:
             //
             // ```
-            // trait SubTrait: SuperTrait<int> { }
+            // trait SubTrait: SuperTrait<i32> { }
             // trait SuperTrait<A> { type T; }
             //
             // ... B: SubTrait<T = foo> ...
             // ```
             //
-            // We want to produce `<B as SuperTrait<int>>::T == foo`.
+            // We want to produce `<B as SuperTrait<i32>>::T == foo`.
 
             // Find any late-bound regions declared in `ty` that are not
             // declared in the trait-ref. These are not well-formed.

src/librustc_typeck/check/compare_method.rs

@@ -91,14 +91,14 @@ fn compare_predicate_entailment<'tcx>(
 
     // This code is best explained by example. Consider a trait:
     //
-    //     trait Trait<'t,T> {
+    //     trait Trait<'t, T> {
-    //          fn method<'a,M>(t: &'t T, m: &'a M) -> Self;
+    //         fn method<'a, M>(t: &'t T, m: &'a M) -> Self;
     //     }
     //
     // And an impl:
     //
     //     impl<'i, 'j, U> Trait<'j, &'i U> for Foo {
-    //          fn method<'b,N>(t: &'j &'i U, m: &'b N) -> Foo;
+    //          fn method<'b, N>(t: &'j &'i U, m: &'b N) -> Foo;
     //     }
     //
     // We wish to decide if those two method types are compatible.
@@ -116,9 +116,9 @@ fn compare_predicate_entailment<'tcx>(
     // regions (Note: but only early-bound regions, i.e., those
     // declared on the impl or used in type parameter bounds).
     //
-    //     impl_to_skol_substs = {'i => 'i0, U => U0, N => N0 }
+    //     impl_to_placeholder_substs = {'i => 'i0, U => U0, N => N0 }
     //
-    // Now we can apply skol_substs to the type of the impl method
+    // Now we can apply placeholder_substs to the type of the impl method
     // to yield a new function type in terms of our fresh, placeholder
     // types:
     //
@@ -127,11 +127,11 @@ fn compare_predicate_entailment<'tcx>(
     // We now want to extract and substitute the type of the *trait*
     // method and compare it. To do so, we must create a compound
     // substitution by combining trait_to_impl_substs and
-    // impl_to_skol_substs, and also adding a mapping for the method
+    // impl_to_placeholder_substs, and also adding a mapping for the method
     // type parameters. We extend the mapping to also include
     // the method parameters.
     //
-    //     trait_to_skol_substs = { T => &'i0 U0, Self => Foo, M => N0 }
+    //     trait_to_placeholder_substs = { T => &'i0 U0, Self => Foo, M => N0 }
     //
     // Applying this to the trait method type yields:
     //
@@ -145,20 +145,20 @@ fn compare_predicate_entailment<'tcx>(
     // satisfied by the implementation's method.
     //
     // We do this by creating a parameter environment which contains a
-    // substitution corresponding to impl_to_skol_substs. We then build
+    // substitution corresponding to impl_to_placeholder_substs. We then build
-    // trait_to_skol_substs and use it to convert the predicates contained
+    // trait_to_placeholder_substs and use it to convert the predicates contained
     // in the trait_m.generics to the placeholder form.
     //
     // Finally we register each of these predicates as an obligation in
     // a fresh FulfillmentCtxt, and invoke select_all_or_error.
 
     // Create mapping from impl to placeholder.
-    let impl_to_skol_substs = InternalSubsts::identity_for_item(tcx, impl_m.def_id);
+    let impl_to_placeholder_substs = InternalSubsts::identity_for_item(tcx, impl_m.def_id);
 
     // Create mapping from trait to placeholder.
-    let trait_to_skol_substs =
+    let trait_to_placeholder_substs =
-        impl_to_skol_substs.rebase_onto(tcx, impl_m.container.id(), trait_to_impl_substs);
+        impl_to_placeholder_substs.rebase_onto(tcx, impl_m.container.id(), trait_to_impl_substs);
-    debug!("compare_impl_method: trait_to_skol_substs={:?}", trait_to_skol_substs);
+    debug!("compare_impl_method: trait_to_placeholder_substs={:?}", trait_to_placeholder_substs);
 
     let impl_m_generics = tcx.generics_of(impl_m.def_id);
     let trait_m_generics = tcx.generics_of(trait_m.def_id);
@@ -194,7 +194,7 @@ fn compare_predicate_entailment<'tcx>(
     // if all constraints hold.
     hybrid_preds
         .predicates
-        .extend(trait_m_predicates.instantiate_own(tcx, trait_to_skol_substs).predicates);
+        .extend(trait_m_predicates.instantiate_own(tcx, trait_to_placeholder_substs).predicates);
 
     // Construct trait parameter environment and then shift it into the placeholder viewpoint.
     // The key step here is to update the caller_bounds's predicates to be
@@ -220,7 +220,7 @@ fn compare_predicate_entailment<'tcx>(
 
         let mut selcx = traits::SelectionContext::new(&infcx);
 
-        let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_skol_substs);
+        let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs);
         let (impl_m_own_bounds, _) = infcx.replace_bound_vars_with_fresh_vars(
             impl_m_span,
             infer::HigherRankedType,
@@ -261,7 +261,7 @@ fn compare_predicate_entailment<'tcx>(
         debug!("compare_impl_method: impl_fty={:?}", impl_fty);
 
         let trait_sig = tcx.liberate_late_bound_regions(impl_m.def_id, &tcx.fn_sig(trait_m.def_id));
-        let trait_sig = trait_sig.subst(tcx, trait_to_skol_substs);
+        let trait_sig = trait_sig.subst(tcx, trait_to_placeholder_substs);
         let trait_sig =
             inh.normalize_associated_types_in(impl_m_span, impl_m_hir_id, param_env, &trait_sig);
         let trait_fty = tcx.mk_fn_ptr(ty::Binder::bind(trait_sig));

src/librustc_typeck/check/method/probe.rs

@@ -1468,7 +1468,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
     ///
     /// ```
     /// trait Foo { ... }
-    /// impl Foo for Vec<int> { ... }
+    /// impl Foo for Vec<i32> { ... }
     /// impl Foo for Vec<usize> { ... }
     /// ```
     ///

src/librustc_typeck/check/pat.rs

@@ -212,7 +212,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // errors in some cases, such as this one:
         //
         // ```
-        // fn foo<'x>(x: &'x int) {
+        // fn foo<'x>(x: &'x i32) {
         //    let a = 1;
         //    let mut z = x;
         //    z = &a;
@@ -220,7 +220,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // ```
         //
         // The reason we might get an error is that `z` might be
-        // assigned a type like `&'x int`, and then we would have
+        // assigned a type like `&'x i32`, and then we would have
         // a problem when we try to assign `&a` to `z`, because
         // the lifetime of `&a` (i.e., the enclosing block) is
         // shorter than `'x`.
@@ -229,11 +229,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // expected type here is whatever type the user wrote, not
         // the initializer's type. In this case the user wrote
         // nothing, so we are going to create a type variable `Z`.
-        // Then we will assign the type of the initializer (`&'x
+        // Then we will assign the type of the initializer (`&'x i32`)
-        // int`) as a subtype of `Z`: `&'x int <: Z`. And hence we
+        // as a subtype of `Z`: `&'x i32 <: Z`. And hence we
-        // will instantiate `Z` as a type `&'0 int` where `'0` is
+        // will instantiate `Z` as a type `&'0 i32` where `'0` is
-        // a fresh region variable, with the constraint that `'x :
+        // a fresh region variable, with the constraint that `'x : '0`.
-        // '0`.  So basically we're all set.
+        // So basically we're all set.
         //
         // Note that there are two tests to check that this remains true
         // (`regions-reassign-{match,let}-bound-pointer.rs`).

src/librustdoc/lib.rs

@@ -9,7 +9,6 @@
 #![feature(nll)]
 #![feature(or_patterns)]
 #![feature(test)]
-#![feature(vec_remove_item)]
 #![feature(ptr_offset_from)]
 #![feature(crate_visibility_modifier)]
 #![feature(never_type)]

src/libstd/sys/sgx/abi/entry.S

@@ -26,18 +26,10 @@ IMAGE_BASE:
 .Lxsave_clear:
 .org .+24
 .Lxsave_mxcsr:
-    .int 0
+    .short 0x1f80
 
 /*  We can store a bunch of data in the gap between MXCSR and the XSAVE header */
 
-/* MXCSR initialization value for ABI */
-.Lmxcsr_init:
-    .int 0x1f80
-
-/* x87 FPU control word initialization value for ABI */
-.Lfpucw_init:
-    .int 0x037f
-
 /*  The following symbols point at read-only data that will be filled in by the */
 /*  post-linker. */
 
@@ -177,13 +169,17 @@ sgx_entry:
     jz .Lskip_debug_init
     mov %r10,%gs:tcsls_debug_panic_buf_ptr
 .Lskip_debug_init:
+/*  reset cpu state */
+    mov %rdx, %r10
+    mov $-1, %rax
+    mov $-1, %rdx
+    xrstor .Lxsave_clear(%rip)
+    mov %r10, %rdx
+
 /*  check if returning from usercall */
     mov %gs:tcsls_last_rsp,%r11
     test %r11,%r11
     jnz .Lusercall_ret
-/*  reset user state */
-    ldmxcsr .Lmxcsr_init(%rip)
-    fldcw .Lfpucw_init(%rip)
 /*  setup stack */
     mov %gs:tcsls_tos,%rsp /*  initially, RSP is not set to the correct value */
                            /*  here. This is fixed below under "adjust stack". */

src/libstd/sys/unix/process/process_common.rs

@@ -428,6 +428,7 @@ mod tests {
     // ignored there.
     #[cfg_attr(target_arch = "arm", ignore)]
     #[cfg_attr(target_arch = "aarch64", ignore)]
+    #[cfg_attr(target_arch = "riscv64", ignore)]
     fn test_process_mask() {
         unsafe {
             // Test to make sure that a signal mask does not get inherited.

src/libstd/time.rs

@@ -811,11 +811,11 @@ mod tests {
 
         // Right now for CI this test is run in an emulator, and apparently the
         // aarch64 emulator's sense of time is that we're still living in the
-        // 70s.
+        // 70s. This is also true for riscv (also qemu)
         //
         // Otherwise let's assume that we're all running computers later than
         // 2000.
-        if !cfg!(target_arch = "aarch64") {
+        if !cfg!(target_arch = "aarch64") && !cfg!(target_arch = "riscv64") {
             assert!(a > thirty_years);
         }
 

src/test/codegen/cfguard_checks.rs

@@ -1,4 +1,4 @@
-// compile-flags: -Z control_flow_guard=checks
+// compile-flags: -Z control-flow-guard=checks
 
 #![crate_type = "lib"]
 

src/test/codegen/cfguard_disabled.rs

@@ -1,4 +1,4 @@
-// compile-flags: -Z control_flow_guard=disabled
+// compile-flags: -Z control-flow-guard=no
 
 #![crate_type = "lib"]
 

src/test/codegen/cfguard_nochecks.rs

@@ -1,4 +1,4 @@
-// compile-flags: -Z control_flow_guard=nochecks
+// compile-flags: -Z control-flow-guard=nochecks
 
 #![crate_type = "lib"]
 

src/test/ui/const-generics/auxiliary/impl-const.rs

@@ -0,0 +1,9 @@
+#![feature(const_generics)]
+
+pub struct Num<const N: usize>;
+
+// Braces around const expression causes crash
+impl Num<{5}> {
+    pub fn five(&self) {
+    }
+}

src/test/ui/const-generics/issue-68104-print-stack-overflow.rs

@@ -0,0 +1,14 @@
+// aux-build:impl-const.rs
+// run-pass
+
+#![feature(const_generics)]
+#![allow(incomplete_features)]
+
+extern crate impl_const;
+
+use impl_const::*;
+
+pub fn main() {
+    let n = Num::<5>;
+    n.five();
+}

src/test/ui/sanitize/unsupported-target.stderr

@@ -1,4 +1,4 @@
-error: `-Zsanitizer=leak` only works with targets: x86_64-apple-darwin, x86_64-unknown-linux-gnu
+error: `-Zsanitizer=leak` only works with targets: aarch64-unknown-linux-gnu, x86_64-apple-darwin, x86_64-unknown-linux-gnu
 
 error: aborting due to previous error
 

src/tools/compiletest/src/main.rs

@@ -1,5 +1,4 @@
 #![crate_name = "compiletest"]
-#![feature(vec_remove_item)]
 #![deny(warnings)]
 // The `test` crate is the only unstable feature
 // allowed here, just to share similar code.

src/tools/compiletest/src/util.rs

@@ -82,16 +82,22 @@ const ARCH_TABLE: &'static [(&'static str, &'static str)] = &[
     ("xcore", "xcore"),
 ];
 
-pub const ASAN_SUPPORTED_TARGETS: &'static [&'static str] =
+pub const ASAN_SUPPORTED_TARGETS: &'static [&'static str] = &[
-    &["aarch64-fuchsia", "x86_64-apple-darwin", "x86_64-fuchsia", "x86_64-unknown-linux-gnu"];
+    "aarch64-fuchsia",
+    "aarch64-unknown-linux-gnu",
+    "x86_64-apple-darwin",
+    "x86_64-fuchsia",
+    "x86_64-unknown-linux-gnu",
+];
 
 pub const LSAN_SUPPORTED_TARGETS: &'static [&'static str] =
-    &["x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+    &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
 
-pub const MSAN_SUPPORTED_TARGETS: &'static [&'static str] = &["x86_64-unknown-linux-gnu"];
+pub const MSAN_SUPPORTED_TARGETS: &'static [&'static str] =
+    &["aarch64-unknown-linux-gnu", "x86_64-unknown-linux-gnu"];
 
 pub const TSAN_SUPPORTED_TARGETS: &'static [&'static str] =
-    &["x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
+    &["aarch64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-unknown-linux-gnu"];
 
 pub fn matches_os(triple: &str, name: &str) -> bool {
     // For the wasm32 bare target we ignore anything also ignored on emscripten

src/tools/remote-test-client/src/main.rs

@@ -107,13 +107,23 @@ fn start_android_emulator(server: &Path) {
     Command::new("adb").arg("shell").arg("/data/tmp/testd").spawn().unwrap();
 }
 
-fn start_qemu_emulator(target: &str, rootfs: &Path, server: &Path, tmpdir: &Path) {
+fn prepare_rootfs(target: &str, rootfs: &Path, server: &Path, rootfs_img: &Path) {
+    t!(fs::copy(server, rootfs.join("testd")));
+
+    match target {
+        "arm-unknown-linux-gnueabihf" | "aarch64-unknown-linux-gnu" => {
+            prepare_rootfs_cpio(rootfs, rootfs_img)
+        }
+        "riscv64gc-unknown-linux-gnu" => prepare_rootfs_ext4(rootfs, rootfs_img),
+        _ => panic!("{} is not supported", target),
+    }
+}
+
+fn prepare_rootfs_cpio(rootfs: &Path, rootfs_img: &Path) {
     // Generate a new rootfs image now that we've updated the test server
     // executable. This is the equivalent of:
     //
     //      find $rootfs -print 0 | cpio --null -o --format=newc > rootfs.img
-    t!(fs::copy(server, rootfs.join("testd")));
-    let rootfs_img = tmpdir.join("rootfs.img");
     let mut cmd = Command::new("cpio");
     cmd.arg("--null")
         .arg("-o")
@@ -128,6 +138,38 @@ fn start_qemu_emulator(target: &str, rootfs: &Path, server: &Path, tmpdir: &Path
     t!(io::copy(&mut child.stdout.take().unwrap(), &mut t!(File::create(&rootfs_img))));
     assert!(t!(child.wait()).success());
 
+    fn add_files(w: &mut dyn Write, root: &Path, cur: &Path) {
+        for entry in t!(cur.read_dir()) {
+            let entry = t!(entry);
+            let path = entry.path();
+            let to_print = path.strip_prefix(root).unwrap();
+            t!(write!(w, "{}\u{0}", to_print.to_str().unwrap()));
+            if t!(entry.file_type()).is_dir() {
+                add_files(w, root, &path);
+            }
+        }
+    }
+}
+
+fn prepare_rootfs_ext4(rootfs: &Path, rootfs_img: &Path) {
+    let mut dd = Command::new("dd");
+    dd.arg("if=/dev/zero")
+        .arg(&format!("of={}", rootfs_img.to_string_lossy()))
+        .arg("bs=1M")
+        .arg("count=1024");
+    let mut dd_child = t!(dd.spawn());
+    assert!(t!(dd_child.wait()).success());
+
+    let mut mkfs = Command::new("mkfs.ext4");
+    mkfs.arg("-d").arg(rootfs).arg(rootfs_img);
+    let mut mkfs_child = t!(mkfs.spawn());
+    assert!(t!(mkfs_child.wait()).success());
+}
+
+fn start_qemu_emulator(target: &str, rootfs: &Path, server: &Path, tmpdir: &Path) {
+    let rootfs_img = &tmpdir.join("rootfs.img");
+    prepare_rootfs(target, rootfs, server, rootfs_img);
+
     // Start up the emulator, in the background
     match target {
         "arm-unknown-linux-gnueabihf" => {
@@ -170,19 +212,30 @@ fn start_qemu_emulator(target: &str, rootfs: &Path, server: &Path, tmpdir: &Path
                 .arg("virtio-net-device,netdev=net0,mac=00:00:00:00:00:00");
             t!(cmd.spawn());
         }
-        _ => panic!("cannot start emulator for: {}" < target),
+        "riscv64gc-unknown-linux-gnu" => {
-    }
+            let mut cmd = Command::new("qemu-system-riscv64");
-
+            cmd.arg("-nographic")
-    fn add_files(w: &mut dyn Write, root: &Path, cur: &Path) {
+                .arg("-machine")
-        for entry in t!(cur.read_dir()) {
+                .arg("virt")
-            let entry = t!(entry);
+                .arg("-m")
-            let path = entry.path();
+                .arg("1024")
-            let to_print = path.strip_prefix(root).unwrap();
+                .arg("-bios")
-            t!(write!(w, "{}\u{0}", to_print.to_str().unwrap()));
+                .arg("none")
-            if t!(entry.file_type()).is_dir() {
+                .arg("-kernel")
-                add_files(w, root, &path);
+                .arg("/tmp/bbl")
-            }
+                .arg("-append")
+                .arg("quiet console=ttyS0 root=/dev/vda rw")
+                .arg("-netdev")
+                .arg("user,id=net0,hostfwd=tcp::12345-:12345")
+                .arg("-device")
+                .arg("virtio-net-device,netdev=net0,mac=00:00:00:00:00:00")
+                .arg("-device")
+                .arg("virtio-blk-device,drive=hd0")
+                .arg("-drive")
+                .arg(&format!("file={},format=raw,id=hd0", &rootfs_img.to_string_lossy()));
+            t!(cmd.spawn());
         }
+        _ => panic!("cannot start emulator for: {}", target),
     }
 }