368281a110
[6/n] rustc: transition HIR function bodies from Block to Expr. _This is part of a series ([prev](https://github.com/rust-lang/rust/pull/37408) | [next](https://github.com/rust-lang/rust/pull/37676)) of patches designed to rework rustc into an out-of-order on-demand pipeline model for both better feature support (e.g. [MIR-based](https://github.com/solson/miri) early constant evaluation) and incremental execution of compiler passes (e.g. type-checking), with beneficial consequences to IDE support as well. If any motivation is unclear, please ask for additional PR description clarifications or code comments._ <hr> The main change here is that functions and closures both use `Expr` instead of `Block` for their bodies. For closures this actually allows a honest representation of brace-less closure bodies, e.g. `|x| x + 1` is now distinguishable from `|x| { x + 1 }`, therefore this PR is `[syntax-breaking]` (cc @Manishearth). Using `Expr` allows more logic to be shared between constant bodies and function bodies, with some small such changes already part of this PR, and eventually easing #35078 and per-body type tables. Incidentally, there used to be some corners cut here and there and as such I had to (re)write divergence tracking for type-checking so that it is capable of understanding basic structured control-flow: ``` rust fn a(x: bool) -> i32 { // match also works (as long as all arms diverge) if x { panic!("true") } else { return 1; } 0 // "unreachable expression" after this PR } ``` And since liveness' "not all control paths return a value" moved to type-checking we can have nice things: ``` rust // before & after: fn b() -> i32 { 0; } // help: consider removing this semicolon // only after this PR fn c() -> i32 { { 0; } } // help: consider removing this semicolon fn d() { let x: i32 = { 0; }; } // help: consider removing this semicolon fn e() { f({ 0; }); } // help: consider removing this semicolon ``` |
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x.py |
The Rust Programming Language
This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.
Quick Start
Read "Installing Rust" from The Book.
Building from Source
-
Make sure you have installed the dependencies:
g++
4.7 or later orclang++
3.xpython
2.7 (but not 3.x)- GNU
make
3.81 or later cmake
3.4.3 or latercurl
git
-
Clone the source with
git
:$ git clone https://github.com/rust-lang/rust.git $ cd rust
-
Build and install:
$ ./configure $ make && make install
Note: You may need to use
sudo make install
if you do not normally have permission to modify the destination directory. The install locations can be adjusted by passing a--prefix
argument toconfigure
. Various other options are also supported – pass--help
for more information on them.When complete,
make install
will place several programs into/usr/local/bin
:rustc
, the Rust compiler, andrustdoc
, the API-documentation tool. This install does not include Cargo, Rust's package manager, which you may also want to build.
Building on Windows
There are two prominent ABIs in use on Windows: the native (MSVC) ABI used by Visual Studio, and the GNU ABI used by the GCC toolchain. Which version of Rust you need depends largely on what C/C++ libraries you want to interoperate with: for interop with software produced by Visual Studio use the MSVC build of Rust; for interop with GNU software built using the MinGW/MSYS2 toolchain use the GNU build.
MinGW
MSYS2 can be used to easily build Rust on Windows:
-
Grab the latest MSYS2 installer and go through the installer.
-
Run
mingw32_shell.bat
ormingw64_shell.bat
from wherever you installed MSYS2 (i.e.C:\msys64
), depending on whether you want 32-bit or 64-bit Rust. (As of the latest version of MSYS2 you have to runmsys2_shell.cmd -mingw32
ormsys2_shell.cmd -mingw64
from the command line instead) -
From this terminal, install the required tools:
# Update package mirrors (may be needed if you have a fresh install of MSYS2) $ pacman -Sy pacman-mirrors # 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 the `python2` and `cmake` packages **not** used. # The build has historically been known to fail with these packages. $ pacman -S git \ make \ diffutils \ tar \ mingw-w64-x86_64-python2 \ mingw-w64-x86_64-cmake \ mingw-w64-x86_64-gcc
-
Navigate to Rust's source code (or clone it), then configure and build it:
$ ./configure $ make && make install
MSVC
MSVC builds of Rust additionally require an installation of Visual Studio 2013
(or later) so rustc
can use its linker. Make sure to check the “C++ tools”
option.
With these dependencies installed, the build takes two steps:
$ ./configure
$ make && make install
MSVC with rustbuild
The old build system, based on makefiles, is currently being rewritten into a Rust-based build system called rustbuild. This can be used to bootstrap the compiler on MSVC without needing to install MSYS or MinGW. All you need are Python 2, CMake, and Git in your PATH (make sure you do not use the ones from MSYS if you have it installed). You'll also need Visual Studio 2013 or newer with the C++ tools. Then all you need to do is to kick off rustbuild.
python x.py build
Currently rustbuild only works with some known versions of Visual Studio. If you have a more recent version installed that a part of rustbuild doesn't understand then you may need to force rustbuild to use an older version. This can be done by manually calling the appropriate vcvars file before running the bootstrap.
CALL "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\amd64\vcvars64.bat"
python x.py build
Building Documentation
If you’d like to build the documentation, it’s almost the same:
$ ./configure
$ make docs
Building the documentation requires building the compiler, so the above details will apply. Once you have the compiler built, you can
$ make docs NO_REBUILD=1
To make sure you don’t re-build the compiler because you made a change to some documentation.
The generated documentation will appear in a top-level doc
directory,
created by the make
rule.
Notes
Since the Rust compiler is written in Rust, it must be built by a precompiled "snapshot" version of itself (made in an earlier state of development). As such, source builds require a connection to the Internet, to 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, Server 2008 R2) | ✓ | ✓ |
Linux (2.6.18 or later) | ✓ | ✓ |
OSX (10.7 Lion or later) | ✓ | ✓ |
You may find that other platforms work, but these are our officially supported build environments that are most likely to work.
Rust currently needs between 600MiB and 1.5GiB to build, depending on platform. If it hits swap, it will take a very long time to build.
There is more advice about hacking on Rust in CONTRIBUTING.md.
Getting Help
The Rust community congregates in a few places:
- Stack Overflow - Direct questions about using the language.
- users.rust-lang.org - General discussion and broader questions.
- /r/rust - News and general discussion.
Contributing
To contribute to Rust, please see CONTRIBUTING.
Rust has an IRC culture and most real-time collaboration happens in a variety of channels on Mozilla's IRC network, irc.mozilla.org. The most popular channel is #rust, a venue for general discussion about Rust. And a good place to ask for help would be #rust-beginners.
License
Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.