Rollup of 19 pull requests

config.toml.example

@@ -90,6 +90,11 @@
 # with clang-cl, so this is special in that it only compiles LLVM with clang-cl
 #clang-cl = '/path/to/clang-cl.exe'
 
+# Pass extra compiler and linker flags to the LLVM CMake build.
+#cflags = "-fextra-flag"
+#cxxflags = "-fextra-flag"
+#ldflags = "-Wl,extra-flag"
+
 # Use libc++ when building LLVM instead of libstdc++. This is the default on
 # platforms already use libc++ as the default C++ library, but this option
 # allows you to use libc++ even on platforms when it's not. You need to ensure

src/bootstrap/config.rs

@@ -82,6 +82,9 @@ pub struct Config {
     pub lldb_enabled: bool,
     pub llvm_tools_enabled: bool,
 
+    pub llvm_cflags: Option<String>,
+    pub llvm_cxxflags: Option<String>,
+    pub llvm_ldflags: Option<String>,
     pub llvm_use_libcxx: bool,
 
     // rust codegen options
@@ -254,6 +257,9 @@ struct Llvm {
     link_shared: Option<bool>,
     version_suffix: Option<String>,
     clang_cl: Option<String>,
+    cflags: Option<String>,
+    cxxflags: Option<String>,
+    ldflags: Option<String>,
     use_libcxx: Option<bool>,
 }
 
@@ -516,6 +522,10 @@ impl Config {
             config.llvm_link_jobs = llvm.link_jobs;
             config.llvm_version_suffix = llvm.version_suffix.clone();
             config.llvm_clang_cl = llvm.clang_cl.clone();
+
+            config.llvm_cflags = llvm.cflags.clone();
+            config.llvm_cxxflags = llvm.cxxflags.clone();
+            config.llvm_ldflags = llvm.ldflags.clone();
             set(&mut config.llvm_use_libcxx, llvm.use_libcxx);
         }
 

src/bootstrap/configure.py

@@ -64,6 +64,10 @@ def v(*args):
 o("missing-tools", "dist.missing-tools", "allow failures when building tools")
 o("use-libcxx", "llvm.use_libcxx", "build LLVM with libc++")
 
+o("cflags", "llvm.cflags", "build LLVM with these extra compiler flags")
+o("cxxflags", "llvm.cxxflags", "build LLVM with these extra compiler flags")
+o("ldflags", "llvm.ldflags", "build LLVM with these extra linker flags")
+
 # Optimization and debugging options. These may be overridden by the release
 # channel, etc.
 o("optimize", "rust.optimize", "build optimized rust code")

src/bootstrap/native.rs

@@ -358,14 +358,21 @@ fn configure_cmake(builder: &Builder,
     }
 
     cfg.build_arg("-j").build_arg(builder.jobs().to_string());
-    cfg.define("CMAKE_C_FLAGS", builder.cflags(target, GitRepo::Llvm).join(" "));
+    let mut cflags = builder.cflags(target, GitRepo::Llvm).join(" ");
+    if let Some(ref s) = builder.config.llvm_cxxflags {
+        cflags.push_str(&format!(" {}", s));
+    }
+    cfg.define("CMAKE_C_FLAGS", cflags);
     let mut cxxflags = builder.cflags(target, GitRepo::Llvm).join(" ");
     if builder.config.llvm_static_stdcpp &&
         !target.contains("windows") &&
         !target.contains("netbsd")
     {
         cxxflags.push_str(" -static-libstdc++");
     }
+    if let Some(ref s) = builder.config.llvm_cxxflags {
+        cxxflags.push_str(&format!(" {}", s));
+    }
     cfg.define("CMAKE_CXX_FLAGS", cxxflags);
     if let Some(ar) = builder.ar(target) {
         if ar.is_absolute() {
@@ -383,6 +390,12 @@ fn configure_cmake(builder: &Builder,
         }
     }
 
+    if let Some(ref s) = builder.config.llvm_ldflags {
+        cfg.define("CMAKE_SHARED_LINKER_FLAGS", s);
+        cfg.define("CMAKE_MODULE_LINKER_FLAGS", s);
+        cfg.define("CMAKE_EXE_LINKER_FLAGS", s);
+    }
+
     if env::var_os("SCCACHE_ERROR_LOG").is_some() {
         cfg.env("RUST_LOG", "sccache=warn");
     }

src/libcore/cmp.rs

@@ -91,6 +91,8 @@ use self::Ordering::*;
 /// For example, let's tweak our previous code a bit:
 ///
 /// ```
+/// // The derive implements <BookFormat> == <BookFormat> comparisons
+/// #[derive(PartialEq)]
 /// enum BookFormat {
 ///     Paperback,
 ///     Hardback,
@@ -102,31 +104,34 @@ use self::Ordering::*;
 ///     format: BookFormat,
 /// }
 ///
+/// // Implement <Book> == <BookFormat> comparisons
 /// impl PartialEq<BookFormat> for Book {
 ///     fn eq(&self, other: &BookFormat) -> bool {
-///         match (&self.format, other) {
-///            (BookFormat::Paperback, BookFormat::Paperback) => true,
-///            (BookFormat::Hardback,  BookFormat::Hardback)  => true,
-///            (BookFormat::Ebook,     BookFormat::Ebook)     => true,
-///            (_, _) => false,
-///         }
+///         self.format == *other
+///     }
+/// }
+///
+/// // Implement <BookFormat> == <Book> comparisons
+/// impl PartialEq<Book> for BookFormat {
+///     fn eq(&self, other: &Book) -> bool {
+///         *self == other.format
 ///     }
 /// }
 ///
 /// let b1 = Book { isbn: 3, format: BookFormat::Paperback };
 ///
 /// assert!(b1 == BookFormat::Paperback);
-/// assert!(b1 != BookFormat::Ebook);
+/// assert!(BookFormat::Ebook != b1);
 /// ```
 ///
 /// By changing `impl PartialEq for Book` to `impl PartialEq<BookFormat> for Book`,
-/// we've changed what type we can use on the right side of the `==` operator.
-/// This lets us use it in the `assert!` statements at the bottom.
+/// we allow `BookFormat`s to be compared with `Book`s.
 ///
 /// You can also combine these implementations to let the `==` operator work with
 /// two different types:
 ///
 /// ```
+/// #[derive(PartialEq)]
 /// enum BookFormat {
 ///     Paperback,
 ///     Hardback,
@@ -140,12 +145,13 @@ use self::Ordering::*;
 ///
 /// impl PartialEq<BookFormat> for Book {
 ///     fn eq(&self, other: &BookFormat) -> bool {
-///         match (&self.format, other) {
-///            (&BookFormat::Paperback, &BookFormat::Paperback) => true,
-///            (&BookFormat::Hardback,  &BookFormat::Hardback)  => true,
-///            (&BookFormat::Ebook,     &BookFormat::Ebook)     => true,
-///            (_, _) => false,
-///         }
+///         self.format == *other
+///     }
+/// }
+///
+/// impl PartialEq<Book> for BookFormat {
+///     fn eq(&self, other: &Book) -> bool {
+///         *self == other.format
 ///     }
 /// }
 ///
@@ -159,7 +165,7 @@ use self::Ordering::*;
 /// let b2 = Book { isbn: 3, format: BookFormat::Ebook };
 ///
 /// assert!(b1 == BookFormat::Paperback);
-/// assert!(b1 != BookFormat::Ebook);
+/// assert!(BookFormat::Ebook != b1);
 /// assert!(b1 == b2);
 /// ```
 ///

src/libcore/ffi.rs

@@ -12,24 +12,27 @@ use ::fmt;
 /// and `*mut c_void` is equivalent to C's `void*`. That said, this is
 /// *not* the same as C's `void` return type, which is Rust's `()` type.
 ///
-/// Ideally, this type would be equivalent to [`!`], but currently it may
-/// be more ideal to use `c_void` for FFI purposes.
+/// To model pointers to opaque types in FFI, until `extern type` is
+/// stabilized, it is recommended to use a newtype wrapper around an empty
+/// byte array. See the [Nomicon] for details.
 ///
-/// [`!`]: ../../std/primitive.never.html
 /// [pointer]: ../../std/primitive.pointer.html
+/// [Nomicon]: https://doc.rust-lang.org/nomicon/ffi.html#representing-opaque-structs
 // N.B., for LLVM to recognize the void pointer type and by extension
 //     functions like malloc(), we need to have it represented as i8* in
 //     LLVM bitcode. The enum used here ensures this and prevents misuse
-//     of the "raw" type by only having private variants.. We need two
+//     of the "raw" type by only having private variants. We need two
 //     variants, because the compiler complains about the repr attribute
-//     otherwise.
+//     otherwise and we need at least one variant as otherwise the enum
+//     would be uninhabited and at least dereferencing such pointers would
+//     be UB.
 #[repr(u8)]
 #[stable(feature = "raw_os", since = "1.1.0")]
 pub enum c_void {
-    #[unstable(feature = "c_void_variant", reason = "should not have to exist",
+    #[unstable(feature = "c_void_variant", reason = "temporary implementation detail",
                issue = "0")]
     #[doc(hidden)] __variant1,
-    #[unstable(feature = "c_void_variant", reason = "should not have to exist",
+    #[unstable(feature = "c_void_variant", reason = "temporary implementation detail",
                issue = "0")]
     #[doc(hidden)] __variant2,
 }
@@ -49,7 +52,7 @@ impl fmt::Debug for c_void {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 extern {
     type VaListImpl;
 }
@@ -74,7 +77,7 @@ impl fmt::Debug for VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 struct VaListImpl {
     stack: *mut (),
     gr_top: *mut (),
@@ -90,7 +93,7 @@ struct VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 struct VaListImpl {
     gpr: u8,
     fpr: u8,
@@ -106,7 +109,7 @@ struct VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 struct VaListImpl {
     gp_offset: i32,
     fp_offset: i32,
@@ -120,7 +123,7 @@ struct VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 #[repr(transparent)]
 pub struct VaList<'a>(&'a mut VaListImpl);
 
@@ -140,7 +143,7 @@ mod sealed_trait {
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
-               issue = "27745")]
+               issue = "44930")]
     pub trait VaArgSafe {}
 }
 
@@ -150,7 +153,7 @@ macro_rules! impl_va_arg_safe {
             #[unstable(feature = "c_variadic",
                        reason = "the `c_variadic` feature has not been properly tested on \
                                  all supported platforms",
-                       issue = "27745")]
+                       issue = "44930")]
             impl sealed_trait::VaArgSafe for $t {}
         )+
     }
@@ -163,20 +166,20 @@ impl_va_arg_safe!{f64}
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 impl<T> sealed_trait::VaArgSafe for *mut T {}
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 impl<T> sealed_trait::VaArgSafe for *const T {}
 
 impl<'a> VaList<'a> {
     /// Advance to the next arg.
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
-               issue = "27745")]
+               issue = "44930")]
     pub unsafe fn arg<T: sealed_trait::VaArgSafe>(&mut self) -> T {
         va_arg(self)
     }
@@ -185,7 +188,7 @@ impl<'a> VaList<'a> {
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
-               issue = "27745")]
+               issue = "44930")]
     pub unsafe fn copy<F, R>(&self, f: F) -> R
             where F: for<'copy> FnOnce(VaList<'copy>) -> R {
         #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),

src/libcore/hint.rs

@@ -49,3 +49,26 @@ use intrinsics;
 pub unsafe fn unreachable_unchecked() -> ! {
     intrinsics::unreachable()
 }
+
+/// Save power or switch hyperthreads in a busy-wait spin-loop.
+///
+/// This function is deliberately more primitive than
+/// [`std::thread::yield_now`](../../std/thread/fn.yield_now.html) and
+/// does not directly yield to the system's scheduler.
+/// In some cases it might be useful to use a combination of both functions.
+/// Careful benchmarking is advised.
+///
+/// On some platforms this function may not do anything at all.
+#[inline]
+#[unstable(feature = "renamed_spin_loop", issue = "55002")]
+pub fn spin_loop() {
+    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+    unsafe {
+        asm!("pause" ::: "memory" : "volatile");
+    }
+
+    #[cfg(target_arch = "aarch64")]
+    unsafe {
+        asm!("yield" ::: "memory" : "volatile");
+    }
+}