Rollup of 6 pull requests

appveyor.yml

@@ -141,15 +141,18 @@ install:
   - set SCCACHE_ERROR_LOG=%CD%/sccache.log
 
 test_script:
-  - appveyor-retry sh -c 'git submodule deinit -f . && git submodule update --init'
+  - if not exist C:\cache\rustsrc\NUL mkdir C:\cache\rustsrc
+  - sh src/ci/init_repo.sh . /c/cache/rustsrc
   - set SRC=.
   - set NO_CCACHE=1
   - sh src/ci/run.sh
 
 on_failure:
-  - cat %CD%/sccache.log
+  - cat %CD%\sccache.log
+  - cat C:\Users\appveyor\AppData\Local\Temp\1\build-cache-logs\*.log
 
 cache:
+  - C:\cache\rustsrc
   - "build/i686-pc-windows-msvc/llvm -> src/rustllvm/llvm-rebuild-trigger"
   - "build/x86_64-pc-windows-msvc/llvm -> src/rustllvm/llvm-rebuild-trigger"
   - "i686-pc-windows-msvc/llvm -> src/rustllvm/llvm-rebuild-trigger"

src/bootstrap/dist.rs

@@ -433,29 +433,32 @@ pub fn rust_src(build: &Build) {
         copy(&build.src.join(item), &dst_src.join(item));
     }
 
-    // Get cargo-vendor installed, if it isn't already.
-    let mut has_cargo_vendor = false;
-    let mut cmd = Command::new(&build.cargo);
-    for line in output(cmd.arg("install").arg("--list")).lines() {
-        has_cargo_vendor |= line.starts_with("cargo-vendor ");
-    }
-    if !has_cargo_vendor {
+    // If we're building from git sources, we need to vendor a complete distribution.
+    if build.src_is_git {
+        // Get cargo-vendor installed, if it isn't already.
+        let mut has_cargo_vendor = false;
+        let mut cmd = Command::new(&build.cargo);
+        for line in output(cmd.arg("install").arg("--list")).lines() {
+            has_cargo_vendor |= line.starts_with("cargo-vendor ");
+        }
+        if !has_cargo_vendor {
+            let mut cmd = Command::new(&build.cargo);
+            cmd.arg("install")
+               .arg("--force")
+               .arg("--debug")
+               .arg("--vers").arg(CARGO_VENDOR_VERSION)
+               .arg("cargo-vendor")
+               .env("RUSTC", &build.rustc);
+            build.run(&mut cmd);
+        }
+
+        // Vendor all Cargo dependencies
         let mut cmd = Command::new(&build.cargo);
-        cmd.arg("install")
-           .arg("--force")
-           .arg("--debug")
-           .arg("--vers").arg(CARGO_VENDOR_VERSION)
-           .arg("cargo-vendor")
-           .env("RUSTC", &build.rustc);
+        cmd.arg("vendor")
+           .current_dir(&dst_src.join("src"));
         build.run(&mut cmd);
     }
 
-    // Vendor all Cargo dependencies
-    let mut cmd = Command::new(&build.cargo);
-    cmd.arg("vendor")
-       .current_dir(&dst_src.join("src"));
-    build.run(&mut cmd);
-
     // Create source tarball in rust-installer format
     let mut cmd = Command::new(SH_CMD);
     cmd.arg(sanitize_sh(&build.src.join("src/rust-installer/gen-installer.sh")))

src/bootstrap/lib.rs

@@ -162,6 +162,7 @@ pub struct Build {
     cxx: HashMap<String, gcc::Tool>,
     crates: HashMap<String, Crate>,
     is_sudo: bool,
+    src_is_git: bool,
 }
 
 #[derive(Debug)]
@@ -233,6 +234,7 @@ impl Build {
         };
         let rust_info = channel::GitInfo::new(&src);
         let cargo_info = channel::GitInfo::new(&src.join("cargo"));
+        let src_is_git = src.join(".git").exists();
 
         Build {
             flags: flags,
@@ -251,6 +253,7 @@ impl Build {
             lldb_version: None,
             lldb_python_dir: None,
             is_sudo: is_sudo,
+            src_is_git: src_is_git,
         }
     }
 
@@ -307,10 +310,7 @@ impl Build {
             OutOfSync,
         }
 
-        if !self.config.submodules {
-            return
-        }
-        if fs::metadata(self.src.join(".git")).is_err() {
+        if !self.src_is_git || !self.config.submodules {
             return
         }
         let git = || {

src/bootstrap/sanity.rs

@@ -65,7 +65,7 @@ pub fn check(build: &mut Build) {
 
     // If we've got a git directory we're gona need git to update
     // submodules and learn about various other aspects.
-    if fs::metadata(build.src.join(".git")).is_ok() {
+    if build.src_is_git {
         need_cmd("git".as_ref());
     }
 

src/ci/docker/README.md

@@ -152,18 +152,13 @@ For targets: `powerpc-unknown-linux-gnu`
 - Path and misc options > Patches origin = Bundled, then local
 - Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = powerpc
-- Target options > Emit assembly for CPU = power4 -- (+)
-- Target options > Tune for CPU = power6 -- (+)
+- Target options > Emit assembly for CPU = powerpc -- pure 32-bit PowerPC
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
 - C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
 - C compiler > gcc version = 4.9.3
-- C compiler > Core gcc extra config = --with-cpu-32=power4 --with-cpu=default32 -- (+)
-- C compiler > gcc extra config = --with-cpu-32=power4 --with-cpu=default32 -- (+)
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
-(+) These CPU options match the configuration of the toolchains in RHEL6.
-
 ## `powerpc64-linux-gnu.config`
 
 For targets: `powerpc64-unknown-linux-gnu`

src/ci/docker/dist-powerpc-linux/powerpc-linux-gnu.config

@@ -101,8 +101,8 @@ CT_ARCH_SUPPORTS_WITH_FLOAT=y
 CT_ARCH_DEFAULT_BE=y
 CT_ARCH_DEFAULT_32=y
 CT_ARCH_ABI=""
-CT_ARCH_CPU="power4"
-CT_ARCH_TUNE="power6"
+CT_ARCH_CPU="powerpc"
+CT_ARCH_TUNE=""
 CT_ARCH_BE=y
 # CT_ARCH_LE is not set
 CT_ARCH_32=y
@@ -391,8 +391,8 @@ CT_CC_GCC_HAS_LIBSANITIZER=y
 CT_CC_GCC_VERSION="4.9.3"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
-CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY="--with-cpu-32=power4 --with-cpu=default32"
-CT_CC_GCC_EXTRA_CONFIG_ARRAY="--with-cpu-32=power4 --with-cpu=default32"
+CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
+CT_CC_GCC_EXTRA_CONFIG_ARRAY=""
 CT_CC_GCC_EXTRA_ENV_ARRAY=""
 CT_CC_GCC_STATIC_LIBSTDCXX=y
 # CT_CC_GCC_SYSTEM_ZLIB is not set

src/ci/init_repo.sh

@@ -38,9 +38,20 @@ fi
 
 # Wipe the cache if it's not valid, or mark it as invalid while we update it
 if [ ! -f "$cache_valid_file" ]; then
-    rm -rf "$CACHE_DIR" && mkdir "$CACHE_DIR"
+    rm -rf "$CACHE_DIR"
+    mkdir "$CACHE_DIR"
 else
-    rm "$cache_valid_file"
+    stat_lines=$(cd "$cache_src_dir" && git status --porcelain | wc -l)
+    stat_ec=$(cd "$cache_src_dir" && git status >/dev/null 2>&1 && echo $?)
+    if [ ! -d "$cache_src_dir/.git" -o $stat_lines != 0 -o $stat_ec != 0 ]; then
+        # Something is badly wrong - the cache valid file is here, but something
+        # about the git repo is fishy. Nuke it all, just in case
+        echo "WARNING: $cache_valid_file exists but bad repo: l:$stat_lines, ec:$stat_ec"
+        rm -rf "$CACHE_DIR"
+        mkdir "$CACHE_DIR"
+    else
+        rm "$cache_valid_file"
+    fi
 fi
 
 # Update the cache (a pristine copy of the rust source master)

src/doc/unstable-book/src/SUMMARY.md

@@ -205,6 +205,7 @@
 - [unwind_attributes](unwind-attributes.md)
 - [update_panic_count](update-panic-count.md)
 - [use_extern_macros](use-extern-macros.md)
+- [used](used.md)
 - [utf8_error_error_len](utf8-error-error-len.md)
 - [vec_remove_item](vec-remove-item.md)
 - [windows_c](windows-c.md)

src/doc/unstable-book/src/used.md

@@ -0,0 +1,153 @@
+# `used`
+
+The tracking issue for this feature
+is: [40289](https://github.com/rust-lang/rust/issues/40289).
+
+------------------------
+
+The `#[used]` attribute can be applied to `static` variables to prevent the Rust
+compiler from optimizing them away even if they appear to be unused by the crate
+(appear to be "dead code").
+
+``` rust
+#![feature(used)]
+
+#[used]
+static FOO: i32 = 1;
+
+static BAR: i32 = 2;
+
+fn main() {}
+```
+
+If you compile this program into an object file, you'll see that `FOO` makes it
+to the object file but `BAR` doesn't. Neither static variable is used by the
+program.
+
+``` text
+$ rustc -C opt-level=3 --emit=obj used.rs
+
+$ nm -C used.o
+0000000000000000 T main
+                 U std::rt::lang_start
+0000000000000000 r used::FOO
+0000000000000000 t used::main
+```
+
+Note that the *linker* knows nothing about the `#[used]` attribute and will
+remove `#[used]` symbols if they are not referenced by other parts of the
+program:
+
+``` text
+$ rustc -C opt-level=3 used.rs
+
+$ nm -C used | grep FOO
+```
+
+"This doesn't sound too useful then!" you may think but keep reading.
+
+To preserve the symbols all the way to the final binary, you'll need the
+cooperation of the linker. Here's one example:
+
+The ELF standard defines two special sections, `.init_array` and
+`.pre_init_array`, that may contain function pointers which will be executed
+*before* the `main` function is invoked. The linker will preserve symbols placed
+in these sections (at least when linking programs that target the `*-*-linux-*`
+targets).
+
+``` rust,ignore
+#![feature(used)]
+
+extern "C" fn before_main() {
+    println!("Hello, world!");
+}
+
+#[link_section = ".init_array"]
+#[used]
+static INIT_ARRAY: [extern "C" fn(); 1] = [before_main];
+
+fn main() {}
+```
+
+So, `#[used]` and `#[link_section]` can be combined to obtain "life before
+main".
+
+``` text
+$ rustc -C opt-level=3 before-main.rs
+
+$ ./before-main
+Hello, world!
+```
+
+Another example: ARM Cortex-M microcontrollers need their reset handler, a
+pointer to the function that will executed right after the microcontroller is
+turned on, to be placed near the start of their FLASH memory to boot properly.
+
+This condition can be met using `#[used]` and `#[link_section]` plus a linker
+script.
+
+``` rust,ignore
+#![feature(lang_items)]
+#![feature(used)]
+#![no_main]
+#![no_std]
+
+extern "C" fn reset_handler() -> ! {
+    loop {}
+}
+
+#[link_section = ".reset_handler"]
+#[used]
+static RESET_HANDLER: extern "C" fn() -> ! = reset_handler;
+
+#[lang = "panic_fmt"]
+fn panic_fmt() {}
+```
+
+``` text
+MEMORY
+{
+  FLASH : ORIGIN = 0x08000000, LENGTH = 128K
+  RAM : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+SECTIONS
+{
+  .text ORIGIN(FLASH) :
+  {
+    /* Vector table */
+    LONG(ORIGIN(RAM) + LENGTH(RAM)); /* initial SP value */
+    KEEP(*(.reset_handler));
+
+    /* Omitted: The rest of the vector table */
+
+    *(.text.*);
+  } > FLASH
+
+  /DISCARD/ :
+  {
+    /* Unused unwinding stuff */
+    *(.ARM.exidx.*)
+  }
+}
+```
+
+``` text
+$ xargo rustc --target thumbv7m-none-eabi --release -- \
+    -C link-arg=-Tlink.x -C link-arg=-nostartfiles
+
+$ arm-none-eabi-objdump -Cd target/thumbv7m-none-eabi/release/app
+./target/thumbv7m-none-eabi/release/app:     file format elf32-littlearm
+
+
+Disassembly of section .text:
+
+08000000 <app::RESET_HANDLER-0x4>:
+ 8000000:       20005000        .word   0x20005000
+
+08000004 <app::RESET_HANDLER>:
+ 8000004:       08000009                                ....
+
+08000008 <app::reset_handler>:
+ 8000008:       e7fe            b.n     8000008 <app::reset_handler>
+```

src/librustc/middle/cstore.rs

@@ -172,7 +172,7 @@ pub trait CrateStore {
     fn stability(&self, def: DefId) -> Option<attr::Stability>;
     fn deprecation(&self, def: DefId) -> Option<attr::Deprecation>;
     fn visibility(&self, def: DefId) -> ty::Visibility;
-    fn visible_parent_map<'a>(&'a self) -> ::std::cell::RefMut<'a, DefIdMap<DefId>>;
+    fn visible_parent_map<'a>(&'a self) -> ::std::cell::Ref<'a, DefIdMap<DefId>>;
     fn item_generics_cloned(&self, def: DefId) -> ty::Generics;
     fn item_attrs(&self, def_id: DefId) -> Vec<ast::Attribute>;
     fn fn_arg_names(&self, did: DefId) -> Vec<ast::Name>;
@@ -302,7 +302,7 @@ impl CrateStore for DummyCrateStore {
     fn stability(&self, def: DefId) -> Option<attr::Stability> { bug!("stability") }
     fn deprecation(&self, def: DefId) -> Option<attr::Deprecation> { bug!("deprecation") }
     fn visibility(&self, def: DefId) -> ty::Visibility { bug!("visibility") }
-    fn visible_parent_map<'a>(&'a self) -> ::std::cell::RefMut<'a, DefIdMap<DefId>> {
+    fn visible_parent_map<'a>(&'a self) -> ::std::cell::Ref<'a, DefIdMap<DefId>> {
         bug!("visible_parent_map")
     }
     fn item_generics_cloned(&self, def: DefId) -> ty::Generics

src/librustc_borrowck/borrowck/README.md

@@ -347,7 +347,7 @@ ALIASABLE(*LV, MQ)                 // M-Deref-Unique
   ALIASABLE(LV, MQ)
 ```
 
-### Checking mutability of immutable pointer types
+### Checking aliasability of immutable pointer types
 
 Immutable pointer types like `&T` are aliasable, and hence can only be
 borrowed immutably:
@@ -357,7 +357,7 @@ ALIASABLE(*LV, imm)                // M-Deref-Borrowed-Imm
   TYPE(LV) = &Ty
 ```
 
-### Checking mutability of mutable pointer types
+### Checking aliasability of mutable pointer types
 
 `&mut T` can be frozen, so it is acceptable to borrow it as either imm or mut:
 
@@ -633,7 +633,7 @@ Here is a concrete example of a bug this rule prevents:
 
 ```rust
 // Test region-reborrow-from-shorter-mut-ref.rs:
-fn copy_pointer<'a,'b,T>(x: &'a mut &'b mut T) -> &'b mut T {
+fn copy_borrowed_ptr<'a,'b,T>(x: &'a mut &'b mut T) -> &'b mut T {
     &mut **p // ERROR due to clause (1)
 }
 fn main() {