Merge rayon-rs#656

656: Rust 1.26 and assorted cleanups r=nikomatsakis a=cuviper

In anticipation of [RFC 3](rayon-rs/rfcs#3), giving us a policy to soon raise our minimum to Rust 1.26, I started this branch to make the conversion. After the primary motivation of upgrading crossbeam, I also looked for ways to use newer language features.

Throughout all of this, the public API should be completely unaffected.

Closes rayon-rs#586 for newer crossbeam, even though we're not quite at the *newest*.

Co-authored-by: Josh Stone <cuviper@gmail.com>

Author: bors[bot]

.travis.yml

@@ -9,19 +9,13 @@ matrix:
   fast_finish: true
   include:
     # NB: To help with CI delays, each `pull_request` is only tested on Linux,
-    # with 1.13 for compatibility and stable+rayon_unstable for broad test
+    # with 1.26 for compatibility and stable+rayon_unstable for broad test
     # coverage.  The bors bot counts as a `push` type, which will run it all.
 
-    - rust: 1.13.0
+    - rust: 1.26.0
       os: linux
       #if: everything!
       script: cargo build
-      before_script:
-        # lazy_static 1.1 requires Rust 1.21+, so downgrade it.
-        # (and docopt 1.1 requires lazy_static 1.3)
-        - cargo generate-lockfile
-        - cargo update -p docopt --precise 1.0.2
-        - cargo update -p lazy_static --precise 1.0.2
 
     - rust: stable
       os: linux

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "rayon"
 # Reminder to update html_rool_url in lib.rs when updating version
-version = "1.0.3"
+version = "1.1.0"
 authors = ["Niko Matsakis <niko@alum.mit.edu>",
            "Josh Stone <cuviper@gmail.com>"]
 description = "Simple work-stealing parallelism for Rust"
@@ -11,16 +11,15 @@ documentation = "https://docs.rs/rayon/"
 readme = "README.md"
 keywords = ["parallel", "thread", "concurrency", "join", "performance"]
 categories = ["concurrency"]
-build = "build.rs"
 exclude = ["/ci/*", "/scripts/*", "/.travis.yml", "/appveyor.yml", "/bors.toml"]
 
 [workspace]
 members = ["rayon-demo", "rayon-core", "rayon-futures"]
 exclude = ["ci"]
 
 [dependencies]
-rayon-core = { version = "1.4.1", path = "rayon-core" }
-crossbeam-deque = "0.2.0"
+rayon-core = { version = "1.5.0", path = "rayon-core" }
+crossbeam-deque = "0.6.3"
 
 # This is a public dependency!
 [dependencies.either]

README.md

@@ -90,7 +90,7 @@ just add:
 use rayon::prelude::*;
 ```
 
-Rayon currently requires `rustc 1.13.0` or greater.
+Rayon currently requires `rustc 1.26.0` or greater.
 
 ## Contribution
 

build.rs

@@ -8,7 +8,7 @@ use docopt::Docopt;
 use std::io;
 use std::process;
 
-const USAGE: &'static str = "
+const USAGE: &str = "
 Usage: cpu_monitor [options] <scenario>
        cpu_monitor --help
 
@@ -76,7 +76,7 @@ fn tasks_ended(args: &Args) {
 }
 
 fn task_stall_root(args: &Args) {
-    rayon::join(|| task(args), || wait_for_user());
+    rayon::join(|| task(args), wait_for_user);
 }
 
 fn task_stall_scope(args: &Args) {

examples/cpu_monitor.rs

@@ -1,6 +1,6 @@
 [package]
 name = "rayon-core"
-version = "1.4.1" # reminder to update html_root_url attribute
+version = "1.5.0" # reminder to update html_root_url attribute
 authors = ["Niko Matsakis <niko@alum.mit.edu>",
            "Josh Stone <cuviper@gmail.com>"]
 description = "Core APIs for Rayon"
@@ -13,24 +13,20 @@ readme = "README.md"
 keywords = ["parallel", "thread", "concurrency", "join", "performance"]
 categories = ["concurrency"]
 
+# Some dependencies may not be their latest version, in order to support older rustc.
 [dependencies]
 num_cpus = "1.2"
-libc = "0.2.16"
 lazy_static = "1"
-
-# This is deliberately not the latest version, because we want
-# to support older rustc than crossbeam-deque 0.3+ does.
-[dependencies.crossbeam-deque]
-version = "0.2.0"
-
-# Also held back for rustc compatibility
-[dependencies.crossbeam]
-version = "0.3.0"
+crossbeam-deque = "0.6.3"
+crossbeam-queue = "0.1.2"
 
 [dev-dependencies]
 rand = "0.6"
 rand_xorshift = "0.1"
 
+[target.'cfg(unix)'.dev-dependencies]
+libc = "0.2"
+
 [[test]]
 name = "stack_overflow_crash"
 path = "tests/stack_overflow_crash.rs"

rayon-core/Cargo.toml

@@ -8,4 +8,4 @@ Please see [Rayon Docs] for details about using Rayon.
 
 [Rayon Docs]: https://docs.rs/rayon/
 
-Rayon-core currently requires `rustc 1.13.0` or greater.
+Rayon-core currently requires `rustc 1.26.0` or greater.

rayon-core/README.md

@@ -60,15 +60,8 @@ pub fn if_in_worker_thread<F, R>(if_true: F) -> Option<R>
 where
     F: FnOnce(&WorkerThread) -> R,
 {
-    let worker_thread = registry::WorkerThread::current();
-    if worker_thread.is_null() {
-        None
-    } else {
-        unsafe {
-            let wt = WorkerThread {
-                thread: &*worker_thread,
-            };
-            Some(if_true(&wt))
-        }
+    unsafe {
+        let thread = registry::WorkerThread::current().as_ref()?;
+        Some(if_true(&WorkerThread { thread }))
     }
 }

rayon-core/src/internal/worker.rs

@@ -1,11 +1,11 @@
-use crossbeam::sync::SegQueue;
+use crossbeam_queue::SegQueue;
 use latch::Latch;
 use std::any::Any;
 use std::cell::UnsafeCell;
 use std::mem;
 use unwind;
 
-pub enum JobResult<T> {
+pub(super) enum JobResult<T> {
     None,
     Ok(T),
     Panic(Box<Any + Send>),
@@ -16,7 +16,7 @@ pub enum JobResult<T> {
 /// arranged in a deque, so that thieves can take from the top of the
 /// deque while the main worker manages the bottom of the deque. This
 /// deque is managed by the `thread_pool` module.
-pub trait Job {
+pub(super) trait Job {
     /// Unsafe: this may be called from a different thread than the one
     /// which scheduled the job, so the implementer must ensure the
     /// appropriate traits are met, whether `Send`, `Sync`, or both.
@@ -30,7 +30,7 @@ pub trait Job {
 /// true type is something like `*const StackJob<...>`, but we hide
 /// it. We also carry the "execute fn" from the `Job` trait.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub struct JobRef {
+pub(super) struct JobRef {
     pointer: *const (),
     execute_fn: unsafe fn(*const ()),
 }
@@ -41,24 +41,21 @@ unsafe impl Sync for JobRef {}
 impl JobRef {
     /// Unsafe: caller asserts that `data` will remain valid until the
     /// job is executed.
-    pub unsafe fn new<T>(data: *const T) -> JobRef
+    pub(super) unsafe fn new<T>(data: *const T) -> JobRef
     where
         T: Job,
     {
         let fn_ptr: unsafe fn(*const T) = <T as Job>::execute;
 
         // erase types:
-        let fn_ptr: unsafe fn(*const ()) = mem::transmute(fn_ptr);
-        let pointer = data as *const ();
-
         JobRef {
-            pointer: pointer,
-            execute_fn: fn_ptr,
+            pointer: data as *const (),
+            execute_fn: mem::transmute(fn_ptr),
         }
     }
 
     #[inline]
-    pub unsafe fn execute(&self) {
+    pub(super) unsafe fn execute(&self) {
         (self.execute_fn)(self.pointer)
     }
 }
@@ -67,13 +64,13 @@ impl JobRef {
 /// executes it need not free any heap data, the cleanup occurs when
 /// the stack frame is later popped.  The function parameter indicates
 /// `true` if the job was stolen -- executed on a different thread.
-pub struct StackJob<L, F, R>
+pub(super) struct StackJob<L, F, R>
 where
     L: Latch + Sync,
     F: FnOnce(bool) -> R + Send,
     R: Send,
 {
-    pub latch: L,
+    pub(super) latch: L,
     func: UnsafeCell<Option<F>>,
     result: UnsafeCell<JobResult<R>>,
 }
@@ -84,23 +81,23 @@ where
     F: FnOnce(bool) -> R + Send,
     R: Send,
 {
-    pub fn new(func: F, latch: L) -> StackJob<L, F, R> {
+    pub(super) fn new(func: F, latch: L) -> StackJob<L, F, R> {
         StackJob {
-            latch: latch,
+            latch,
             func: UnsafeCell::new(Some(func)),
             result: UnsafeCell::new(JobResult::None),
         }
     }
 
-    pub unsafe fn as_job_ref(&self) -> JobRef {
+    pub(super) unsafe fn as_job_ref(&self) -> JobRef {
         JobRef::new(self)
     }
 
-    pub unsafe fn run_inline(self, stolen: bool) -> R {
+    pub(super) unsafe fn run_inline(self, stolen: bool) -> R {
         self.func.into_inner().unwrap()(stolen)
     }
 
-    pub unsafe fn into_result(self) -> R {
+    pub(super) unsafe fn into_result(self) -> R {
         self.result.into_inner().into_return_value()
     }
 }
@@ -130,7 +127,7 @@ where
 /// signal that the job executed.
 ///
 /// (Probably `StackJob` should be refactored in a similar fashion.)
-pub struct HeapJob<BODY>
+pub(super) struct HeapJob<BODY>
 where
     BODY: FnOnce() + Send,
 {
@@ -141,7 +138,7 @@ impl<BODY> HeapJob<BODY>
 where
     BODY: FnOnce() + Send,
 {
-    pub fn new(func: BODY) -> Self {
+    pub(super) fn new(func: BODY) -> Self {
         HeapJob {
             job: UnsafeCell::new(Some(func)),
         }
@@ -150,7 +147,7 @@ where
     /// Creates a `JobRef` from this job -- note that this hides all
     /// lifetimes, so it is up to you to ensure that this JobRef
     /// doesn't outlive any data that it closes over.
-    pub unsafe fn as_job_ref(self: Box<Self>) -> JobRef {
+    pub(super) unsafe fn as_job_ref(self: Box<Self>) -> JobRef {
         let this: *const Self = mem::transmute(self);
         JobRef::new(this)
     }
@@ -172,7 +169,7 @@ impl<T> JobResult<T> {
     /// its JobResult is populated) into its return value.
     ///
     /// NB. This will panic if the job panicked.
-    pub fn into_return_value(self) -> T {
+    pub(super) fn into_return_value(self) -> T {
         match self {
             JobResult::None => unreachable!(),
             JobResult::Ok(x) => x,
@@ -182,18 +179,18 @@ impl<T> JobResult<T> {
 }
 
 /// Indirect queue to provide FIFO job priority.
-pub struct JobFifo {
+pub(super) struct JobFifo {
     inner: SegQueue<JobRef>,
 }
 
 impl JobFifo {
-    pub fn new() -> Self {
+    pub(super) fn new() -> Self {
         JobFifo {
             inner: SegQueue::new(),
         }
     }
 
-    pub unsafe fn push(&self, job_ref: JobRef) -> JobRef {
+    pub(super) unsafe fn push(&self, job_ref: JobRef) -> JobRef {
         // A little indirection ensures that spawns are always prioritized in FIFO order.  The
         // jobs in a thread's deque may be popped from the back (LIFO) or stolen from the front
         // (FIFO), but either way they will end up popping from the front of this queue.
@@ -205,10 +202,6 @@ impl JobFifo {
 impl Job for JobFifo {
     unsafe fn execute(this: *const Self) {
         // We "execute" a queue by executing its first job, FIFO.
-        (*this)
-            .inner
-            .try_pop()
-            .expect("job in fifo queue")
-            .execute()
+        (*this).inner.pop().expect("job in fifo queue").execute()
     }
 }

rayon-core/src/job.rs

@@ -171,7 +171,7 @@ where
             }
         }
 
-        return (result_a, job_b.into_result());
+        (result_a, job_b.into_result())
     })
 }