Remove (lots of) dead code

Found with https://github.com/est31/warnalyzer.

Dubious changes:
- Is anyone else using rustc_apfloat? I feel weird completely deleting
  x87 support.
- Maybe some of the dead code in rustc_data_structures, in case someone
  wants to use it in the future?
- Don't change rustc_serialize

  I plan to scrap most of the json module in the near future (see
  https://github.com/rust-lang/compiler-team/issues/418) and fixing the
  tests needed more work than I expected.

TODO: check if any of the comments on the deleted code should be kept.

compiler/rustc_data_structures/src/sync.rs

@@ -43,46 +43,6 @@ cfg_if! {
         use std::ops::Add;
         use std::panic::{resume_unwind, catch_unwind, AssertUnwindSafe};
 
-        /// This is a single threaded variant of AtomicCell provided by crossbeam.
-        /// Unlike `Atomic` this is intended for all `Copy` types,
-        /// but it lacks the explicit ordering arguments.
-        #[derive(Debug)]
-        pub struct AtomicCell<T: Copy>(Cell<T>);
-
-        impl<T: Copy> AtomicCell<T> {
-            #[inline]
-            pub fn new(v: T) -> Self {
-                AtomicCell(Cell::new(v))
-            }
-
-            #[inline]
-            pub fn get_mut(&mut self) -> &mut T {
-                self.0.get_mut()
-            }
-        }
-
-        impl<T: Copy> AtomicCell<T> {
-            #[inline]
-            pub fn into_inner(self) -> T {
-                self.0.into_inner()
-            }
-
-            #[inline]
-            pub fn load(&self) -> T {
-                self.0.get()
-            }
-
-            #[inline]
-            pub fn store(&self, val: T) {
-                self.0.set(val)
-            }
-
-            #[inline]
-            pub fn swap(&self, val: T) -> T {
-                self.0.replace(val)
-            }
-        }
-
         /// This is a single threaded variant of `AtomicU64`, `AtomicUsize`, etc.
         /// It differs from `AtomicCell` in that it has explicit ordering arguments
         /// and is only intended for use with the native atomic types.
@@ -99,11 +59,6 @@ cfg_if! {
         }
 
         impl<T: Copy> Atomic<T> {
-            #[inline]
-            pub fn into_inner(self) -> T {
-                self.0.into_inner()
-            }
-
             #[inline]
             pub fn load(&self, _: Ordering) -> T {
                 self.0.get()
@@ -113,11 +68,6 @@ cfg_if! {
             pub fn store(&self, val: T, _: Ordering) {
                 self.0.set(val)
             }
-
-            #[inline]
-            pub fn swap(&self, val: T, _: Ordering) -> T {
-                self.0.replace(val)
-            }
         }
 
         impl<T: Copy + PartialEq> Atomic<T> {
@@ -159,22 +109,6 @@ cfg_if! {
             (oper_a(), oper_b())
         }
 
-        pub struct SerialScope;
-
-        impl SerialScope {
-            pub fn spawn<F>(&self, f: F)
-                where F: FnOnce(&SerialScope)
-            {
-                f(self)
-            }
-        }
-
-        pub fn scope<F, R>(f: F) -> R
-            where F: FnOnce(&SerialScope) -> R
-        {
-            f(&SerialScope)
-        }
-
         #[macro_export]
         macro_rules! parallel {
             ($($blocks:tt),*) => {
@@ -246,12 +180,6 @@ cfg_if! {
             pub fn new<F: FnMut(usize) -> T>(mut f: F) -> WorkerLocal<T> {
                 WorkerLocal(OneThread::new(f(0)))
             }
-
-            /// Returns the worker-local value for each thread
-            #[inline]
-            pub fn into_inner(self) -> Vec<T> {
-                vec![OneThread::into_inner(self.0)]
-            }
         }
 
         impl<T> Deref for WorkerLocal<T> {
@@ -279,16 +207,6 @@ cfg_if! {
                 self.0
             }
 
-            #[inline(always)]
-            pub fn get_mut(&mut self) -> &mut T {
-                &mut self.0
-            }
-
-            #[inline(always)]
-            pub fn lock(&self) -> &T {
-                &self.0
-            }
-
             #[inline(always)]
             pub fn lock_mut(&mut self) -> &mut T {
                 &mut self.0
@@ -521,16 +439,6 @@ impl<T> RwLock<T> {
         RwLock(InnerRwLock::new(inner))
     }
 
-    #[inline(always)]
-    pub fn into_inner(self) -> T {
-        self.0.into_inner()
-    }
-
-    #[inline(always)]
-    pub fn get_mut(&mut self) -> &mut T {
-        self.0.get_mut()
-    }
-
     #[cfg(not(parallel_compiler))]
     #[inline(always)]
     pub fn read(&self) -> ReadGuard<'_, T> {
@@ -547,11 +455,6 @@ impl<T> RwLock<T> {
         }
     }
 
-    #[inline(always)]
-    pub fn with_read_lock<F: FnOnce(&T) -> R, R>(&self, f: F) -> R {
-        f(&*self.read())
-    }
-
     #[cfg(not(parallel_compiler))]
     #[inline(always)]
     pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
@@ -580,11 +483,6 @@ impl<T> RwLock<T> {
         }
     }
 
-    #[inline(always)]
-    pub fn with_write_lock<F: FnOnce(&mut T) -> R, R>(&self, f: F) -> R {
-        f(&mut *self.write())
-    }
-
     #[inline(always)]
     pub fn borrow(&self) -> ReadGuard<'_, T> {
         self.read()
@@ -633,12 +531,6 @@ impl<T> OneThread<T> {
             inner,
         }
     }
-
-    #[inline(always)]
-    pub fn into_inner(value: Self) -> T {
-        value.check();
-        value.inner
-    }
 }
 
 impl<T> Deref for OneThread<T> {

compiler/rustc_data_structures/src/tagged_ptr/drop.rs

@@ -42,18 +42,9 @@ where
     pub fn pointer_ref(&self) -> &P::Target {
         self.raw.pointer_ref()
     }
-    pub fn pointer_mut(&mut self) -> &mut P::Target
-    where
-        P: std::ops::DerefMut,
-    {
-        self.raw.pointer_mut()
-    }
     pub fn tag(&self) -> T {
         self.raw.tag()
     }
-    pub fn set_tag(&mut self, tag: T) {
-        self.raw.set_tag(tag);
-    }
 }
 
 impl<P, T, const COMPARE_PACKED: bool> std::ops::Deref for TaggedPtr<P, T, COMPARE_PACKED>

compiler/rustc_data_structures/src/work_queue.rs

@@ -41,10 +41,4 @@ impl<T: Idx> WorkQueue<T> {
             None
         }
     }
-
-    /// Returns `true` if nothing is enqueued.
-    #[inline]
-    pub fn is_empty(&self) -> bool {
-        self.deque.is_empty()
-    }
 }