Auto merge of #54389 - kennytm:rollup, r=kennytm

Rollup of 15 pull requests

Successful merges:

 - #52813 (Duration div mul extras)
 - #53470 (Warn about metadata loader errors)
 - #54233 (Remove LLVM 3.9 workaround.)
 - #54257 (Switch wasm math symbols to their original names)
 - #54258 (Enable fatal warnings for the wasm32 linker)
 - #54266 (Update LLVM to fix "bool" arguments on PPC32)
 - #54290 (Switch linker for aarch64-pc-windows-msvc from LLD to MSVC)
 - #54292 (Suggest array indexing when tuple indexing on an array)
 - #54295 (A few cleanups and minor improvements to rustc/traits)
 - #54298 (miri: correctly compute expected alignment for field)
 - #54333 (Update The Book to latest)
 - #54337 (Remove unneeded clone() from tests in librustdoc)
 - #54346 (rustc: future-proof error reporting for polymorphic constants in types.)
 - #54362 (Pass --batch to gdb)
 - #54367 (Add regression test for thread local static mut borrows)

.travis.yml

@@ -301,7 +301,7 @@ after_failure:
       EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|');
       if [ -f "$EXE" ]; then
         printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE";
-        gdb -q -c "$CORE" "$EXE"
+        gdb --batch -q -c "$CORE" "$EXE"
           -iex 'set auto-load off'
           -iex 'dir src/'
           -iex 'set sysroot .'

src/libcore/time.rs

@@ -21,7 +21,7 @@
 //! assert_eq!(Duration::new(5, 0), Duration::from_secs(5));
 //! ```
 
-use fmt;
+use {fmt, u64};
 use iter::Sum;
 use ops::{Add, Sub, Mul, Div, AddAssign, SubAssign, MulAssign, DivAssign};
 
@@ -30,6 +30,7 @@ const NANOS_PER_MILLI: u32 = 1_000_000;
 const NANOS_PER_MICRO: u32 = 1_000;
 const MILLIS_PER_SEC: u64 = 1_000;
 const MICROS_PER_SEC: u64 = 1_000_000;
+const MAX_NANOS_F64: f64 = ((u64::MAX as u128 + 1)*(NANOS_PER_SEC as u128)) as f64;
 
 /// A `Duration` type to represent a span of time, typically used for system
 /// timeouts.
@@ -458,6 +459,115 @@ impl Duration {
             None
         }
     }
+
+    /// Returns the number of seconds contained by this `Duration` as `f64`.
+    ///
+    /// The returned value does include the fractional (nanosecond) part of the duration.
+    ///
+    /// # Examples
+    /// ```
+    /// #![feature(duration_float)]
+    /// use std::time::Duration;
+    ///
+    /// let dur = Duration::new(2, 700_000_000);
+    /// assert_eq!(dur.as_float_secs(), 2.7);
+    /// ```
+    #[unstable(feature = "duration_float", issue = "54361")]
+    #[inline]
+    pub fn as_float_secs(&self) -> f64 {
+        (self.secs as f64) + (self.nanos as f64) / (NANOS_PER_SEC as f64)
+    }
+
+    /// Creates a new `Duration` from the specified number of seconds.
+    ///
+    /// # Panics
+    /// This constructor will panic if `secs` is not finite, negative or overflows `Duration`.
+    ///
+    /// # Examples
+    /// ```
+    /// #![feature(duration_float)]
+    /// use std::time::Duration;
+    ///
+    /// let dur = Duration::from_float_secs(2.7);
+    /// assert_eq!(dur, Duration::new(2, 700_000_000));
+    /// ```
+    #[unstable(feature = "duration_float", issue = "54361")]
+    #[inline]
+    pub fn from_float_secs(secs: f64) -> Duration {
+        let nanos =  secs * (NANOS_PER_SEC as f64);
+        if !nanos.is_finite() {
+            panic!("got non-finite value when converting float to duration");
+        }
+        if nanos >= MAX_NANOS_F64 {
+            panic!("overflow when converting float to duration");
+        }
+        if nanos < 0.0 {
+            panic!("underflow when converting float to duration");
+        }
+        let nanos =  nanos as u128;
+        Duration {
+            secs: (nanos / (NANOS_PER_SEC as u128)) as u64,
+            nanos: (nanos % (NANOS_PER_SEC as u128)) as u32,
+        }
+    }
+
+    /// Multiply `Duration` by `f64`.
+    ///
+    /// # Panics
+    /// This method will panic if result is not finite, negative or overflows `Duration`.
+    ///
+    /// # Examples
+    /// ```
+    /// #![feature(duration_float)]
+    /// use std::time::Duration;
+    ///
+    /// let dur = Duration::new(2, 700_000_000);
+    /// assert_eq!(dur.mul_f64(3.14), Duration::new(8, 478_000_000));
+    /// assert_eq!(dur.mul_f64(3.14e5), Duration::new(847_800, 0));
+    /// ```
+    #[unstable(feature = "duration_float", issue = "54361")]
+    #[inline]
+    pub fn mul_f64(self, rhs: f64) -> Duration {
+        Duration::from_float_secs(rhs * self.as_float_secs())
+    }
+
+    /// Divide `Duration` by `f64`.
+    ///
+    /// # Panics
+    /// This method will panic if result is not finite, negative or overflows `Duration`.
+    ///
+    /// # Examples
+    /// ```
+    /// #![feature(duration_float)]
+    /// use std::time::Duration;
+    ///
+    /// let dur = Duration::new(2, 700_000_000);
+    /// assert_eq!(dur.div_f64(3.14), Duration::new(0, 859_872_611));
+    /// // note that truncation is used, not rounding
+    /// assert_eq!(dur.div_f64(3.14e5), Duration::new(0, 8_598));
+    /// ```
+    #[unstable(feature = "duration_float", issue = "54361")]
+    #[inline]
+    pub fn div_f64(self, rhs: f64) -> Duration {
+        Duration::from_float_secs(self.as_float_secs() / rhs)
+    }
+
+    /// Divide `Duration` by `Duration` and return `f64`.
+    ///
+    /// # Examples
+    /// ```
+    /// #![feature(duration_float)]
+    /// use std::time::Duration;
+    ///
+    /// let dur1 = Duration::new(2, 700_000_000);
+    /// let dur2 = Duration::new(5, 400_000_000);
+    /// assert_eq!(dur1.div_duration(dur2), 0.5);
+    /// ```
+    #[unstable(feature = "duration_float", issue = "54361")]
+    #[inline]
+    pub fn div_duration(self, rhs: Duration) -> f64 {
+        self.as_float_secs() / rhs.as_float_secs()
+    }
 }
 
 #[stable(feature = "duration", since = "1.3.0")]
@@ -501,6 +611,15 @@ impl Mul<u32> for Duration {
     }
 }
 
+#[stable(feature = "symmetric_u32_duration_mul", since = "1.31.0")]
+impl Mul<Duration> for u32 {
+    type Output = Duration;
+
+    fn mul(self, rhs: Duration) -> Duration {
+        rhs * self
+    }
+}
+
 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
 impl MulAssign<u32> for Duration {
     fn mul_assign(&mut self, rhs: u32) {

src/librustc/traits/auto_trait.rs

@@ -112,17 +112,18 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                 orig_params,
                 trait_pred.to_poly_trait_predicate(),
             ));
+
             match result {
                 Ok(Some(Vtable::VtableImpl(_))) => {
                     debug!(
                         "find_auto_trait_generics(did={:?}, trait_did={:?}, generics={:?}): \
                          manual impl found, bailing out",
                         did, trait_did, generics
                     );
-                    return true;
+                    true
                 }
-                _ => return false,
-            };
+                _ => false
+            }
         });
 
         // If an explicit impl exists, it always takes priority over an auto impl
@@ -426,6 +427,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                     if new_trait.def_id() == old_trait.def_id() {
                         let new_substs = new_trait.skip_binder().trait_ref.substs;
                         let old_substs = old_trait.skip_binder().trait_ref.substs;
+
                         if !new_substs.types().eq(old_substs.types()) {
                             // We can't compare lifetimes if the types are different,
                             // so skip checking old_pred
@@ -489,12 +491,12 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
 
     pub fn get_lifetime(&self, region: Region, names_map: &FxHashMap<String, String>) -> String {
         self.region_name(region)
-            .map(|name| {
-                names_map.get(&name).unwrap_or_else(|| {
+            .map(|name|
+                names_map.get(&name).unwrap_or_else(||
                     panic!("Missing lifetime with name {:?} for {:?}", name, region)
-                })
-            })
-            .unwrap_or(&"'static".to_string())
+                )
+            )
+            .unwrap_or(&"'static".to_owned())
             .clone()
     }
 

src/librustc/traits/codegen/mod.rs

@@ -39,7 +39,7 @@ pub fn codegen_fulfill_obligation<'a, 'tcx>(ty: TyCtxt<'a, 'tcx, 'tcx>,
     let trait_ref = ty.erase_regions(&trait_ref);
 
     debug!("codegen_fulfill_obligation(trait_ref={:?}, def_id={:?})",
-            (param_env, trait_ref), trait_ref.def_id());
+        (param_env, trait_ref), trait_ref.def_id());
 
     // Do the initial selection for the obligation. This yields the
     // shallow result we are looking for -- that is, what specific impl.
@@ -48,8 +48,8 @@ pub fn codegen_fulfill_obligation<'a, 'tcx>(ty: TyCtxt<'a, 'tcx, 'tcx>,
 
         let obligation_cause = ObligationCause::dummy();
         let obligation = Obligation::new(obligation_cause,
-                                            param_env,
-                                            trait_ref.to_poly_trait_predicate());
+                                         param_env,
+                                         trait_ref.to_poly_trait_predicate());
 
         let selection = match selcx.select(&obligation) {
             Ok(Some(selection)) => selection,
@@ -61,12 +61,11 @@ pub fn codegen_fulfill_obligation<'a, 'tcx>(ty: TyCtxt<'a, 'tcx, 'tcx>,
                 // overflow bug, since I believe this is the only case
                 // where ambiguity can result.
                 bug!("Encountered ambiguity selecting `{:?}` during codegen, \
-                        presuming due to overflow",
-                        trait_ref)
+                      presuming due to overflow",
+                      trait_ref)
             }
             Err(e) => {
-                bug!("Encountered error `{:?}` selecting `{:?}` during codegen",
-                            e, trait_ref)
+                bug!("Encountered error `{:?}` selecting `{:?}` during codegen", e, trait_ref)
             }
         };
 
@@ -163,22 +162,16 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         // In principle, we only need to do this so long as `result`
         // contains unbound type parameters. It could be a slight
         // optimization to stop iterating early.
-        match fulfill_cx.select_all_or_error(self) {
-            Ok(()) => { }
-            Err(errors) => {
-                span_bug!(span, "Encountered errors `{:?}` resolving bounds after type-checking",
-                          errors);
-            }
+        if let Err(errors) = fulfill_cx.select_all_or_error(self) {
+            span_bug!(span, "Encountered errors `{:?}` resolving bounds after type-checking",
+                      errors);
         }
 
         let result = self.resolve_type_vars_if_possible(result);
         let result = self.tcx.erase_regions(&result);
 
-        match self.tcx.lift_to_global(&result) {
-            Some(result) => result,
-            None => {
-                span_bug!(span, "Uninferred types/regions in `{:?}`", result);
-            }
-        }
+        self.tcx.lift_to_global(&result).unwrap_or_else(||
+            span_bug!(span, "Uninferred types/regions in `{:?}`", result)
+        )
     }
 }

src/librustc/traits/coherence.rs

@@ -115,9 +115,7 @@ fn overlap<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
                             b_def_id: DefId)
                             -> Option<OverlapResult<'tcx>>
 {
-    debug!("overlap(a_def_id={:?}, b_def_id={:?})",
-           a_def_id,
-           b_def_id);
+    debug!("overlap(a_def_id={:?}, b_def_id={:?})", a_def_id, b_def_id);
 
     // For the purposes of this check, we don't bring any skolemized
     // types into scope; instead, we replace the generic types with
@@ -133,10 +131,9 @@ fn overlap<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
 
     // Do `a` and `b` unify? If not, no overlap.
     let obligations = match selcx.infcx().at(&ObligationCause::dummy(), param_env)
-                                         .eq_impl_headers(&a_impl_header, &b_impl_header) {
-        Ok(InferOk { obligations, value: () }) => {
-            obligations
-        }
+                                         .eq_impl_headers(&a_impl_header, &b_impl_header)
+    {
+        Ok(InferOk { obligations, value: () }) => obligations,
         Err(_) => return None
     };
 
@@ -164,7 +161,7 @@ fn overlap<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
         return None
     }
 
-    let impl_header =  selcx.infcx().resolve_type_vars_if_possible(&a_impl_header);
+    let impl_header = selcx.infcx().resolve_type_vars_if_possible(&a_impl_header);
     let intercrate_ambiguity_causes = selcx.take_intercrate_ambiguity_causes();
     debug!("overlap: intercrate_ambiguity_causes={:#?}", intercrate_ambiguity_causes);
     Some(OverlapResult { impl_header, intercrate_ambiguity_causes })
@@ -471,14 +468,12 @@ fn ty_is_local_constructor(ty: Ty, in_crate: InCrate) -> bool {
         ty::Foreign(did) => def_id_is_local(did, in_crate),
 
         ty::Dynamic(ref tt, ..) => {
-            tt.principal().map_or(false, |p| {
+            tt.principal().map_or(false, |p|
                 def_id_is_local(p.def_id(), in_crate)
-            })
+            )
         }
 
-        ty::Error => {
-            true
-        }
+        ty::Error => true,
 
         ty::Closure(..) |
         ty::Generator(..) |