Auto merge of #34139 - steveklabnik:rollup, r=steveklabnik

Rollup of 13 pull requests

- Successful merges: #33645, #33897, #33945, #34007, #34060, #34070, #34094, #34098, #34099, #34104, #34124, #34125, #34138
- Failed merges:

Author: bors

CONTRIBUTING.md

@@ -108,7 +108,8 @@ root.
 There are large number of options accepted by this script to alter the
 configuration used later in the build process. Some options to note:
 
-- `--enable-debug` - Build a debug version of the compiler (disables optimizations)
+- `--enable-debug` - Build a debug version of the compiler (disables optimizations,
+    which speeds up compilation of stage1 rustc)
 - `--enable-optimize` - Enable optimizations (can be used with `--enable-debug`
     to make a debug build with optimizations)
 - `--disable-valgrind-rpass` - Don't run tests with valgrind
@@ -128,6 +129,12 @@ Some common make targets are:
   cases we don't need to build the stage2 compiler, so we can save time by not
   building it. The stage1 compiler is a fully functioning compiler and
   (probably) will be enough to determine if your change works as expected.
+- `make $host/stage1/bin/rustc` - Where $host is a target triple like x86_64-unknown-linux-gnu.
+  This will build just rustc, without libstd. This is the fastest way to recompile after
+  you changed only rustc source code. Note however that the resulting rustc binary
+  won't have a stdlib to link against by default. You can build libstd once with
+  `make rustc-stage1`, rustc will pick it up afterwards. libstd is only guaranteed to
+  work if recompiled, so if there are any issues recompile it.
 - `make check` - build the full compiler & run all tests (takes a while). This
   is what gets run by the continuous integration system against your pull
   request. You should run this before submitting to make sure your tests pass

Makefile.in

@@ -62,6 +62,8 @@
 #   * tidy - Basic style check, show highest rustc error code and
 #     the status of language and lib features
 #   * rustc-stage$(stage) - Only build up to a specific stage
+#   * $host/stage1/bin/rustc - Only build stage1 rustc, not libstd. For further
+#     information see "Rust recipes for build system success" below.
 #
 # Then mix in some of these environment variables to harness the
 # ultimate power of The Rust Build System.
@@ -93,6 +95,15 @@
 #     // Modifying libstd? Use this command to run unit tests just on your change
 #     make check-stage1-std NO_REBUILD=1 NO_BENCH=1
 #
+#     // Modifying just rustc?
+#     // Compile rustc+libstd once
+#     make rustc-stage1
+#     // From now on use this command to rebuild just rustc and reuse the previously built libstd
+#     // $host is a target triple, eg. x86_64-unknown-linux-gnu
+#     // The resulting binary is located at $host/stage1/bin/rustc.
+#     // If there are any issues with libstd recompile it with the command above.
+#     make $host/stage1/bin/rustc
+#
 #     // Added a run-pass test? Use this to test running your test
 #     make check-stage1-rpass TESTNAME=my-shiny-new-test
 #

configure

@@ -988,11 +988,11 @@ then
     LLVM_VERSION=$($LLVM_CONFIG --version)
 
     case $LLVM_VERSION in
-        (3.[6-8]*)
+        (3.[7-8]*)
             msg "found ok version of LLVM: $LLVM_VERSION"
             ;;
         (*)
-            err "bad LLVM version: $LLVM_VERSION, need >=3.6"
+            err "bad LLVM version: $LLVM_VERSION, need >=3.7"
             ;;
     esac
 fi

src/doc/book/functions.md

@@ -249,7 +249,7 @@ stack backtrace:
 If you need to override an already set `RUST_BACKTRACE`, 
 in cases when you cannot just unset the variable, 
 then set it to `0` to avoid getting a backtrace. 
-Any other value(even no value at all) turns on backtrace.
+Any other value (even no value at all) turns on backtrace.
 
 ```text
 $ export RUST_BACKTRACE=1

src/doc/book/testing.md

@@ -380,8 +380,9 @@ the `tests` directory.
 
 # The `tests` directory
 
-To write an integration test, let's make a `tests` directory, and
-put a `tests/lib.rs` file inside, with this as its contents:
+Each file in `tests/*.rs` directory is treated as individual crate.
+So, to write an integration test, let's make a `tests` directory, and
+put a `tests/integration_test.rs` file inside, with this as its contents:
 
 ```rust,ignore
 extern crate adder;
@@ -394,8 +395,8 @@ fn it_works() {
 ```
 
 This looks similar to our previous tests, but slightly different. We now have
-an `extern crate adder` at the top. This is because the tests in the `tests`
-directory are an entirely separate crate, and so we need to import our library.
+an `extern crate adder` at the top. This is because each test in the `tests`
+directory is an entirely separate crate, and so we need to import our library.
 This is also why `tests` is a suitable place to write integration-style tests:
 they use the library like any other consumer of it would.
 
@@ -428,6 +429,11 @@ test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured
 Now we have three sections: our previous test is also run, as well as our new
 one.
 
+Cargo will ignore files in subdirectories of the `tests/` directory.
+Therefore shared modules in integrations tests are possible.
+For example `tests/common/mod.rs` is not seperatly compiled by cargo but can 
+be imported in every test with `mod common;`
+
 That's all there is to the `tests` directory. The `tests` module isn't needed
 here, since the whole thing is focused on tests.
 

src/doc/book/variable-bindings.md

@@ -37,8 +37,8 @@ of our minds as we go forward.
 Rust is a statically typed language, which means that we specify our types up
 front, and they’re checked at compile time. So why does our first example
 compile? Well, Rust has this thing called ‘type inference’. If it can figure
-out what the type of something is, Rust doesn’t require you to actually type it
-out.
+out what the type of something is, Rust doesn’t require you to explicitly type
+it out.
 
 We can add the type if we want to, though. Types come after a colon (`:`):
 
@@ -159,8 +159,9 @@ error: aborting due to previous error
 Could not compile `hello_world`.
 ```
 
-Rust will not let us use a value that has not been initialized. Next, let’s
-talk about this stuff we've added to `println!`.
+Rust will not let us use a value that has not been initialized.
+
+Let take a minute to talk about this stuff we've added to `println!`.
 
 If you include two curly braces (`{}`, some call them moustaches...) in your
 string to print, Rust will interpret this as a request to interpolate some sort
@@ -222,8 +223,8 @@ To learn more, run the command again with --verbose.
 ```
 
 Additionally, variable bindings can be shadowed. This means that a later
-variable binding with the same name as another binding, that's currently in
-scope, will override the previous binding.
+variable binding with the same name as another binding that is currently in
+scope will override the previous binding.
 
 ```rust
 let x: i32 = 8;
@@ -240,7 +241,10 @@ println!("{}", x); // Prints "42"
 Shadowing and mutable bindings may appear as two sides of the same coin, but
 they are two distinct concepts that can't always be used interchangeably. For
 one, shadowing enables us to rebind a name to a value of a different type. It
-is also possible to change the mutability of a binding.
+is also possible to change the mutability of a binding. Note that shadowing a 
+name does not alter or destroy the value it was bound to, and the value will
+continue to exist until it goes out of scope, even if it is no longer accessible
+by any means.
 
 ```rust
 let mut x: i32 = 1;

src/doc/reference.md

@@ -1983,6 +1983,7 @@ macro scope.
 
 ### Miscellaneous attributes
 
+- `deprecated` - mark the item as deprecated; the full attribute is `#[deprecated(since = "crate version", note = "...")`, where both arguments are optional.
 - `export_name` - on statics and functions, this determines the name of the
   exported symbol.
 - `link_section` - on statics and functions, this specifies the section of the
@@ -2426,8 +2427,6 @@ The currently implemented features of the reference compiler are:
 * - `stmt_expr_attributes` - Allows attributes on expressions and
                              non-item statements.
 
-* - `deprecated` - Allows using the `#[deprecated]` attribute.
-
 * - `type_ascription` - Allows type ascription expressions `expr: Type`.
 
 * - `abi_vectorcall` - Allows the usage of the vectorcall calling convention

src/doc/rust.css

@@ -229,7 +229,7 @@ a > code {
 pre.rust .kw { color: #8959A8; }
 pre.rust .kw-2, pre.rust .prelude-ty { color: #4271AE; }
 pre.rust .number, pre.rust .string { color: #718C00; }
-pre.rust .self, pre.rust .boolval, pre.rust .prelude-val,
+pre.rust .self, pre.rust .bool-val, pre.rust .prelude-val,
 pre.rust .attribute, pre.rust .attribute .ident { color: #C82829; }
 pre.rust .comment { color: #8E908C; }
 pre.rust .doccomment { color: #4D4D4C; }

src/liballoc/rc.rs

@@ -271,7 +271,7 @@ impl<T> Rc<T> {
 }
 
 impl<T: ?Sized> Rc<T> {
-    /// Downgrades the `Rc<T>` to a `Weak<T>` reference.
+    /// Creates a new `Weak<T>` reference from this value.
     ///
     /// # Examples
     ///

src/libcollections/str.rs

@@ -1404,8 +1404,8 @@ impl str {
     /// Returns a string slice with all prefixes and suffixes that match a
     /// pattern repeatedly removed.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines
-    /// if a character matches.
+    /// The pattern can be a [`char`] or a closure that determines if a
+    /// character matches.
     ///
     /// [`char`]: primitive.char.html
     ///

src/libpanic_unwind/dwarf/eh.rs

@@ -24,36 +24,35 @@
 use dwarf::DwarfReader;
 use core::mem;
 
-pub const DW_EH_PE_omit     : u8 = 0xFF;
-pub const DW_EH_PE_absptr   : u8 = 0x00;
-
-pub const DW_EH_PE_uleb128  : u8 = 0x01;
-pub const DW_EH_PE_udata2   : u8 = 0x02;
-pub const DW_EH_PE_udata4   : u8 = 0x03;
-pub const DW_EH_PE_udata8   : u8 = 0x04;
-pub const DW_EH_PE_sleb128  : u8 = 0x09;
-pub const DW_EH_PE_sdata2   : u8 = 0x0A;
-pub const DW_EH_PE_sdata4   : u8 = 0x0B;
-pub const DW_EH_PE_sdata8   : u8 = 0x0C;
-
-pub const DW_EH_PE_pcrel    : u8 = 0x10;
-pub const DW_EH_PE_textrel  : u8 = 0x20;
-pub const DW_EH_PE_datarel  : u8 = 0x30;
-pub const DW_EH_PE_funcrel  : u8 = 0x40;
-pub const DW_EH_PE_aligned  : u8 = 0x50;
-
-pub const DW_EH_PE_indirect : u8 = 0x80;
+pub const DW_EH_PE_omit: u8 = 0xFF;
+pub const DW_EH_PE_absptr: u8 = 0x00;
+
+pub const DW_EH_PE_uleb128: u8 = 0x01;
+pub const DW_EH_PE_udata2: u8 = 0x02;
+pub const DW_EH_PE_udata4: u8 = 0x03;
+pub const DW_EH_PE_udata8: u8 = 0x04;
+pub const DW_EH_PE_sleb128: u8 = 0x09;
+pub const DW_EH_PE_sdata2: u8 = 0x0A;
+pub const DW_EH_PE_sdata4: u8 = 0x0B;
+pub const DW_EH_PE_sdata8: u8 = 0x0C;
+
+pub const DW_EH_PE_pcrel: u8 = 0x10;
+pub const DW_EH_PE_textrel: u8 = 0x20;
+pub const DW_EH_PE_datarel: u8 = 0x30;
+pub const DW_EH_PE_funcrel: u8 = 0x40;
+pub const DW_EH_PE_aligned: u8 = 0x50;
+
+pub const DW_EH_PE_indirect: u8 = 0x80;
 
 #[derive(Copy, Clone)]
 pub struct EHContext {
-    pub ip: usize,         // Current instruction pointer
+    pub ip: usize, // Current instruction pointer
     pub func_start: usize, // Address of the current function
     pub text_start: usize, // Address of the code section
     pub data_start: usize, // Address of the data section
 }
 
-pub unsafe fn find_landing_pad(lsda: *const u8, context: &EHContext)
-                               -> Option<usize> {
+pub unsafe fn find_landing_pad(lsda: *const u8, context: &EHContext) -> Option<usize> {
     if lsda.is_null() {
         return None;
     }
@@ -80,7 +79,7 @@ pub unsafe fn find_landing_pad(lsda: *const u8, context: &EHContext)
     let action_table = reader.ptr.offset(call_site_table_length as isize);
     // Return addresses point 1 byte past the call instruction, which could
     // be in the next IP range.
-    let ip = context.ip-1;
+    let ip = context.ip - 1;
 
     while reader.ptr < action_table {
         let cs_start = read_encoded_pointer(&mut reader, context, call_site_encoding);
@@ -90,7 +89,7 @@ pub unsafe fn find_landing_pad(lsda: *const u8, context: &EHContext)
         // Callsite table is sorted by cs_start, so if we've passed the ip, we
         // may stop searching.
         if ip < func_start + cs_start {
-            break
+            break;
         }
         if ip < func_start + cs_start + cs_len {
             if cs_lpad != 0 {
@@ -114,13 +113,13 @@ fn round_up(unrounded: usize, align: usize) -> usize {
 
 unsafe fn read_encoded_pointer(reader: &mut DwarfReader,
                                context: &EHContext,
-                               encoding: u8) -> usize {
+                               encoding: u8)
+                               -> usize {
     assert!(encoding != DW_EH_PE_omit);
 
     // DW_EH_PE_aligned implies it's an absolute pointer value
     if encoding == DW_EH_PE_aligned {
-        reader.ptr = round_up(reader.ptr as usize,
-                              mem::size_of::<usize>()) as *const u8;
+        reader.ptr = round_up(reader.ptr as usize, mem::size_of::<usize>()) as *const u8;
         return reader.read::<usize>();
     }
 
@@ -134,20 +133,26 @@ unsafe fn read_encoded_pointer(reader: &mut DwarfReader,
         DW_EH_PE_sdata2 => reader.read::<i16>() as usize,
         DW_EH_PE_sdata4 => reader.read::<i32>() as usize,
         DW_EH_PE_sdata8 => reader.read::<i64>() as usize,
-        _ => panic!()
+        _ => panic!(),
     };
 
     result += match encoding & 0x70 {
         DW_EH_PE_absptr => 0,
         // relative to address of the encoded value, despite the name
         DW_EH_PE_pcrel => reader.ptr as usize,
-        DW_EH_PE_textrel => { assert!(context.text_start != 0);
-                              context.text_start },
-        DW_EH_PE_datarel => { assert!(context.data_start != 0);
-                              context.data_start },
-        DW_EH_PE_funcrel => { assert!(context.func_start != 0);
-                              context.func_start },
-        _ => panic!()
+        DW_EH_PE_textrel => {
+            assert!(context.text_start != 0);
+            context.text_start
+        }
+        DW_EH_PE_datarel => {
+            assert!(context.data_start != 0);
+            context.data_start
+        }
+        DW_EH_PE_funcrel => {
+            assert!(context.func_start != 0);
+            context.func_start
+        }
+        _ => panic!(),
     };
 
     if encoding & DW_EH_PE_indirect != 0 {

src/libpanic_unwind/dwarf/mod.rs

@@ -21,25 +21,22 @@ pub mod eh;
 use core::mem;
 
 pub struct DwarfReader {
-    pub ptr : *const u8
+    pub ptr: *const u8,
 }
 
 #[repr(C,packed)]
 struct Unaligned<T>(T);
 
 impl DwarfReader {
-
-    pub fn new(ptr : *const u8) -> DwarfReader {
-        DwarfReader {
-            ptr : ptr
-        }
+    pub fn new(ptr: *const u8) -> DwarfReader {
+        DwarfReader { ptr: ptr }
     }
 
     // DWARF streams are packed, so e.g. a u32 would not necessarily be aligned
     // on a 4-byte boundary. This may cause problems on platforms with strict
     // alignment requirements. By wrapping data in a "packed" struct, we are
     // telling the backend to generate "misalignment-safe" code.
-    pub unsafe fn read<T:Copy>(&mut self) -> T {
+    pub unsafe fn read<T: Copy>(&mut self) -> T {
         let Unaligned(result) = *(self.ptr as *const Unaligned<T>);
         self.ptr = self.ptr.offset(mem::size_of::<T>() as isize);
         result
@@ -48,9 +45,9 @@ impl DwarfReader {
     // ULEB128 and SLEB128 encodings are defined in Section 7.6 - "Variable
     // Length Data".
     pub unsafe fn read_uleb128(&mut self) -> u64 {
-        let mut shift : usize = 0;
-        let mut result : u64 = 0;
-        let mut byte : u8;
+        let mut shift: usize = 0;
+        let mut result: u64 = 0;
+        let mut byte: u8;
         loop {
             byte = self.read::<u8>();
             result |= ((byte & 0x7F) as u64) << shift;
@@ -63,9 +60,9 @@ impl DwarfReader {
     }
 
     pub unsafe fn read_sleb128(&mut self) -> i64 {
-        let mut shift : usize = 0;
-        let mut result : u64 = 0;
-        let mut byte : u8;
+        let mut shift: usize = 0;
+        let mut result: u64 = 0;
+        let mut byte: u8;
         loop {
             byte = self.read::<u8>();
             result |= ((byte & 0x7F) as u64) << shift;
@@ -84,12 +81,7 @@ impl DwarfReader {
 
 #[test]
 fn dwarf_reader() {
-    let encoded: &[u8] = &[1,
-                           2, 3,
-                           4, 5, 6, 7,
-                           0xE5, 0x8E, 0x26,
-                           0x9B, 0xF1, 0x59,
-                           0xFF, 0xFF];
+    let encoded: &[u8] = &[1, 2, 3, 4, 5, 6, 7, 0xE5, 0x8E, 0x26, 0x9B, 0xF1, 0x59, 0xFF, 0xFF];
 
     let mut reader = DwarfReader::new(encoded.as_ptr());