89cc8529cc
It is intended to optimize/beautify the code generated in a few trivial trait operations. Let's take the following code as an example: ``` trait Stuff { fn bar(&self); } fn callBar(s: &Stuff) { s.bar(); } struct Foo; impl Stuff for Foo { fn bar(&self) { } } pub fn main() { let o = Foo; callBar(&o as &Stuff); } ``` At present it is translated into something like: ``` define void @_ZN7callBar_UUID.0E({ i32, %tydesc*, i8*, i8*, i8 }*, { %tydesc*, i8* }*) #4 { "function top level": %__trait_callee = alloca { %tydesc*, i8* } %__auto_borrow_obj = alloca { %tydesc*, i8* } %2 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 0 %3 = load %tydesc** %2 %4 = getelementptr inbounds { %tydesc*, i8* }* %__auto_borrow_obj, i32 0, i32 0 store %tydesc* %3, %tydesc** %4 %5 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 1 %6 = load i8** %5 %7 = getelementptr inbounds { %tydesc*, i8* }* %__auto_borrow_obj, i32 0, i32 1 store i8* %6, i8** %7 %8 = bitcast { %tydesc*, i8* }* %__auto_borrow_obj to i8* %9 = bitcast { %tydesc*, i8* }* %__trait_callee to i8* call void @llvm.memcpy.p0i8.p0i8.i32(i8* %9, i8* %8, i32 8, i32 4, i1 false) %10 = getelementptr inbounds { %tydesc*, i8* }* %__trait_callee, i32 0, i32 1 %11 = load i8** %10 %12 = bitcast i8* %11 to { i32, %tydesc*, i8*, i8*, i8 }* %13 = getelementptr inbounds { %tydesc*, i8* }* %__trait_callee, i32 0, i32 0 %14 = bitcast %tydesc** %13 to [1 x i8*]** %15 = load [1 x i8*]** %14 %16 = getelementptr inbounds [1 x i8*]* %15, i32 0, i32 1 %17 = load i8** %16 %18 = bitcast i8* %17 to void ({ i32, %tydesc*, i8*, i8*, i8 }*)* call void %18({ i32, %tydesc*, i8*, i8*, i8 }* %12) ret void } ... define void @_ZN4main_UUID.0E({ i32, %tydesc*, i8*, i8*, i8 }*) #4 { "function top level": %o = alloca %struct.Foo %1 = alloca { %tydesc*, i8* } %__auto_borrow_obj = alloca { %tydesc*, i8* } %2 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 1 %3 = bitcast i8** %2 to %struct.Foo** store %struct.Foo* %o, %struct.Foo** %3 %4 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 0 %5 = bitcast %tydesc** %4 to { %tydesc*, void ({ i32, %tydesc*, i8*, i8*, i8 }*)* }** store { %tydesc*, void ({ i32, %tydesc*, i8*, i8*, i8 }*)* }* @vtable1081, { %tydesc*, void ({ i32, %tydesc*, i8*, i8*, i8 }*)* }** %5 %6 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 0 %7 = load %tydesc** %6 %8 = getelementptr inbounds { %tydesc*, i8* }* %__auto_borrow_obj, i32 0, i32 0 store %tydesc* %7, %tydesc** %8 %9 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 1 %10 = load i8** %9 %11 = getelementptr inbounds { %tydesc*, i8* }* %__auto_borrow_obj, i32 0, i32 1 store i8* %10, i8** %11 call void @_ZN7callBar_UUID.0E({ i32, %tydesc*, i8*, i8*, i8 }* undef, { %tydesc*, i8* }* %__auto_borrow_obj) ret void } ``` If you apply my patch, it would become way shorter and cleaner: ``` define void @_ZN7callBar_UUID.0E({ i32, %tydesc*, i8*, i8*, i8 }*, { %tydesc*, i8* }*) #4 { "function top level": %2 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 1 %3 = load i8** %2 %4 = bitcast i8* %3 to { i32, %tydesc*, i8*, i8*, i8 }* %5 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 0 %6 = bitcast %tydesc** %5 to [1 x i8*]** %7 = load [1 x i8*]** %6 %8 = getelementptr inbounds [1 x i8*]* %7, i32 0, i32 1 %9 = load i8** %8 %10 = bitcast i8* %9 to void ({ i32, %tydesc*, i8*, i8*, i8 }*)* call void %10({ i32, %tydesc*, i8*, i8*, i8 }* %4) ret void } ... define void @_ZN4main_UUID.0E({ i32, %tydesc*, i8*, i8*, i8 }*) #4 { "function top level": %o = alloca %struct.Foo %1 = alloca { %tydesc*, i8* } %2 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 1 %3 = bitcast i8** %2 to %struct.Foo** store %struct.Foo* %o, %struct.Foo** %3 %4 = getelementptr inbounds { %tydesc*, i8* }* %1, i32 0, i32 0 %5 = bitcast %tydesc** %4 to { %tydesc*, void ({ i32, %tydesc*, i8*, i8*, i8 }*)* }** store { %tydesc*, void ({ i32, %tydesc*, i8*, i8*, i8 }*)* }* @vtable1081, { %tydesc*, void ({ i32, %tydesc*, i8*, i8*, i8 }*)* }** %5 call void @_ZN7callBar_UUID.0E({ i32, %tydesc*, i8*, i8*, i8 }* undef, { %tydesc*, i8* }* %1) ret void } ``` Although this change doesn't increase the compilation speed much (I mentioned only about 1-2% boost on "rustc -O -Z time-passes syntax.rs"), but I still think it's a good thing to do as it greatly simplifies/clarifies LL generated in some cases which would definitely help in the future code generation investigations. I don't provide any new test cases in this patch as it is merely an optimization. Sorry guys, I somehow messed my previous PR and I don't see any better way to fix as to recreate it here. |
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AUTHORS.txt | ||
CONTRIBUTING.md | ||
COPYRIGHT | ||
LICENSE-APACHE | ||
LICENSE-MIT | ||
Makefile.in | ||
README.md | ||
RELEASES.txt | ||
configure |
README.md
The Rust Programming Language
This is a compiler for Rust, including standard libraries, tools and documentation.
Quick Start
Windows
Note: Windows users should read the detailed getting started notes on the wiki. Even when using the binary installer the Windows build requires a MinGW installation, the precise details of which are not discussed here.
Linux / OS X
-
Install the prerequisites (if not already installed)
- g++ 4.4 or clang++ 3.x
- python 2.6 or later (but not 3.x)
- perl 5.0 or later
- gnu make 3.81 or later
- curl
-
Download and build Rust You can either download a tarball or build directly from the repo.
To build from the tarball do:
$ curl -O http://static.rust-lang.org/dist/rust-0.7.tar.gz $ tar -xzf rust-0.7.tar.gz $ cd rust-0.7
Or to build from the repo do:
$ git clone https://github.com/mozilla/rust.git $ cd rust
Now that you have Rust's source code, you can configure and build it:
$ ./configure $ make && make install
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;rustdoc
, the API-documentation tool, andrustpkg
, the Rust package manager and build system. -
Read the tutorial.
-
Enjoy!
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:
- Windows (7, Server 2008 R2), x86 only
- Linux (various distributions), x86 and x86-64
- OSX 10.6 ("Snow Leopard") or greater, x86 and x86-64
You may find that other platforms work, but these are our "tier 1" supported build environments that are most likely to work.
Rust currently needs about 1.8G of RAM to build without swapping; if it hits swap, it will take a very long time to build.
There is lots more documentation in the wiki.
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.