d6d0590469
Remove the ParamSpace separation from formal and actual generics in rustc. This is the first step towards enabling the typesystem implemented by `rustc` to be extended (with generic modules, HKT associated types, generics over constants, etc.). The current implementation splits all formal (`ty::Generics`) and actual (`Substs`) lifetime and type parameters (and even `where` clauses) into 3 "parameter spaces": * `TypeSpace` for `enum`, `struct`, `trait` and `impl` * `SelfSpace` for `Self` in a `trait` * `FnSpace` for functions and methods For example, in `<X as Trait<A, B>>::method::<T, U>`, the `Substs` are `[[A, B], [X], [T, U]]`. The representation uses a single `Vec` with 2 indices where it's split into the 3 "parameter spaces". Such a simplistic approach doesn't scale beyond the Rust 1.0 typesystem, and its existence was mainly motivated by keeping code manipulating generic parameters correct, across all possible situations. Summary of changes: * `ty::Generics` are uniformly stored and can be queried with `tcx.lookup_generics(def_id)` * the `typeck::collect` changes for this resulted in a function to lazily compute the `ty::Generics` for a local node, given only its `DefId` - this can be further generalized to other kinds of type information * `ty::Generics` and `ty::GenericPredicates` now contain only their own parameters (or `where` clauses, respectively), and refer to their "parent", forming a linked list * right now most items have one level of nesting, only associated items and variants having two * in the future, if `<X as mod1<A>::mod2<B>::mod3::Trait<C>>::Assoc<Y>` is supported, it would be represented by item with the path `mod1::mod2::mod3::Trait::Assoc`, and 4 levels of generics: `mod1` with `[A]`, `mod2` with `[B]`, `Trait` with `[X, C]` and `Assoc` with `[Y]` * `Substs` gets two new APIs for working with arbitrary items: * `Substs::for_item(def_id, mk_region, mk_type)` will construct `Substs` expected by the definition `def_id`, calling `mk_region` for lifetime parameters and `mk_type` for type parameters, and it's guaranteed to *always* return `Substs` compatible with `def_id` * `substs.rebase_onto(from_base_def_id, to_base_substs)` can be used if `substs` is for an item nested within `from_base_def_id` (e.g. an associated item), to replace the "outer parameters" with `to_base_substs` - for example, you can translate a method's `Substs` between a `trait` and an `impl` (in both directions) if you have the `DefId` of one and `Substs` for the other * trait objects, without a `Self` in their `Substs`, use *solely* `ExistentialTraitRef` now, letting `TraitRef` assume it *always* has a `Self` present * both `TraitRef` and `ExistentialTraitRef` get methods which do operations on their `Substs` which are valid only for traits (or trait objects, respectively) * `Substs` loses its "parameter spaces" distinction, with effectively no code creating `Substs` in an ad-hoc manner, or inspecting them, without knowing what shape they have already Future plans: * combine both lifetimes and types in a single `Vec<Kind<'tcx>>` where `Kind` would be a tagged pointer that can be `Ty<'tcx>`, `&'tcx ty::Region` or, in the future, potentially-polymorphic constants * this would require some performance investigation, if it implies a lot of dynamic checks * introduce an abstraction for `(T, Substs)`, where the `Substs` are even more hidden away from code manipulating it; a precedent for this is `Instance` in trans, which has `T = DefId`; @nikomatsakis also referred to this, as "lazy substitution", when `T = Ty` * rewrite type pretty-printing to fully take advantage of this to inject actual in the exact places of formal generic parameters in any paths * extend the set of type-level information (e.g. beyond `ty::Generics`) that can be lazily queried during `typeck` and introduce a way to do those queries from code that can't refer to `typeck` directly * this is almost unrelated but is necessary for DAG-shaped recursion between constant evaluation and type-level information, i.e. for implementing generics over constants r? @nikomatsakis cc @rust-lang/compiler cc @nrc Could get any perf numbers ahead of merging this?
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.xpython2.7 (but not 3.x)- GNU
make3.81 or later cmake2.8.8 or latercurlgit
-
Clone the source with
git:$ git clone https://github.com/rust-lang/rust.git $ cd rust
-
Build and install:
$ ./configure $ make && make installNote: You may need to use
sudo make installif you do not normally have permission to modify the destination directory. The install locations can be adjusted by passing a--prefixargument toconfigure. Various other options are also supported – pass--helpfor more information on them.When complete,
make installwill 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.batormingw64_shell.batfrom 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 -mingw32ormsys2_shell.cmd -mingw64from 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 \ 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 .\src\bootstrap\bootstrap.py
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 .\src\bootstrap\bootstrap.py
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.