perf: walk liveness backwards in Conflicts::build

[rust.git] / README.md

diff --git a/README.md b/README.md
index 3399f7fe6c8b1463b4c432986a7f90f68561f154..cb5d71477d81026f6b71e6d4fc9a24aff3c4b00a 100644 (file)
--- a/README.md
+++ b/README.md
@@ -7,7 +7,10 @@ standard library, and documentation.
 
 [Rust]: https://www.rust-lang.org
 
-**Note: this README is for _users_ rather than _contributors_.**
+**Note: this README is for _users_ rather than _contributors_.
+If you wish to _contribute_ to the compiler, you should read the
+[Getting Started][gettingstarted] of the rustc-dev-guide instead of this
+section.**
 
 ## Quick Start
 
@@ -18,10 +21,6 @@ Read ["Installation"] from [The Book].
 
 ## Installing from Source
 
-**Note: If you wish to _contribute_ to the compiler, you should read the
-[Getting Started][gettingstarted] of the rustc-dev-guide instead of this
-section.**
-
 The Rust build system uses a Python script called `x.py` to build the compiler,
 which manages the bootstrapping process. More information about it can be found
 by running `./x.py --help` or reading the [rustc dev guide][rustcguidebuild].
@@ -36,6 +35,7 @@ by running `./x.py --help` or reading the [rustc dev guide][rustcguidebuild].
    * `python` 3 or 2.7
    * GNU `make` 3.81 or later
    * `cmake` 3.4.3 or later
+   * `ninja`
    * `curl`
    * `git`
    * `ssl` which comes in `libssl-dev` or `openssl-devel`
@@ -111,7 +111,7 @@ build.
    # Install build tools needed for Rust. If you're building a 32-bit compiler,
    # then replace "x86_64" below with "i686". If you've already got git, python,
    # or CMake installed and in PATH you can remove them from this list. Note
-   # that it is important that you do **not** use the 'python2' and 'cmake'
+   # that it is important that you do **not** use the 'python2', 'cmake' and 'ninja'
    # packages from the 'msys2' subsystem. The build has historically been known
    # to fail with these packages.
    $ pacman -S git \
@@ -120,7 +120,8 @@ build.
                tar \
                mingw-w64-x86_64-python \
                mingw-w64-x86_64-cmake \
-               mingw-w64-x86_64-gcc
+               mingw-w64-x86_64-gcc \
+               mingw-w64-x86_64-ninja
    ```
 
 4. Navigate to Rust's source code (or clone it), then build it:
@@ -209,11 +210,17 @@ fetch snapshots, and an OS that can execute the available snapshot binaries.
 
 Snapshot binaries are currently built and tested on several platforms:
 
-| Platform / Architecture    | x86 | x86_64 |
-|----------------------------|-----|--------|
-| Windows (7, 8, 10, ...)    | ✓   | ✓      |
-| Linux (2.6.18 or later)    | ✓   | ✓      |
-| macOS (10.7 Lion or later) | ✓   | ✓      |
+| Platform / Architecture                     | x86 | x86_64 |
+|---------------------------------------------|-----|--------|
+| Windows (7, 8, 10, ...)                     | ✓   | ✓      |
+| Linux (kernel 2.6.32, glibc 2.11 or later)  | ✓   | ✓      |
+| macOS (10.7 Lion or later)                  | (\*) | ✓      |
+
+(\*): Apple dropped support for running 32-bit binaries starting from macOS 10.15 and iOS 11.
+Due to this decision from Apple, the targets are no longer useful to our users.
+Please read [our blog post][macx32] for more info.
+
+[macx32]: https://blog.rust-lang.org/2020/01/03/reducing-support-for-32-bit-apple-targets.html
 
 You may find that other platforms work, but these are our officially
 supported build environments that are most likely to work.
@@ -235,6 +242,8 @@ The Rust community congregates in a few places:
 If you are interested in contributing to the Rust project, please take a look
 at the [Getting Started][gettingstarted] guide in the [rustc-dev-guide].
 
+[rustc-dev-guide]: https://rustc-dev-guide.rust-lang.org
+
 ## License
 
 Rust is primarily distributed under the terms of both the MIT license