X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=Readme.md;h=dad8ed90b53b8307fb1c4b72d40b15a59c2878bd;hb=ad5966ed4c2625270092f5b7ac93bf61c9f59f06;hp=5d86ae5e525b1b13f54f85ffcce40907ec531dd0;hpb=a3283962bc289326c2b908681f0a476c53f428b7;p=rust.git

diff --git a/Readme.md b/Readme.md
index 5d86ae5e525..dad8ed90b53 100644
--- a/Readme.md
+++ b/Readme.md
@@ -1,54 +1,75 @@
-# WIP Cranelift codegen backend for rust
+# Cranelift codegen backend for rust
 
-> ⚠⚠⚠ Certain kinds of FFI don't work yet. ⚠⚠⚠
+The goal of this project is to create an alternative codegen backend for the rust compiler based on [Cranelift](https://github.com/bytecodealliance/wasmtime/blob/main/cranelift).
+This has the potential to improve compilation times in debug mode.
+If your project doesn't use any of the things listed under "Not yet supported", it should work fine.
+If not please open an issue.
 
-## Building
+## Building and testing
 
 ```bash
 $ git clone https://github.com/bjorn3/rustc_codegen_cranelift.git
 $ cd rustc_codegen_cranelift
-$ ./prepare.sh # download and patch sysroot src and install hyperfine for benchmarking
-$ ./test.sh --release
+$ ./y.rs prepare # download and patch sysroot src and install hyperfine for benchmarking
+$ ./y.rs build
 ```
 
-## Usage
-
-`$cg_clif_dir` is the directory you cloned this repo into in the following instruction.
-
-### Cargo
+To run the test suite replace the last command with:
 
 ```bash
-$ CHANNEL="release" $cg_clif_dir/cargo.sh run
+$ ./test.sh
 ```
 
-If you compiled cg_clif in debug mode you should use `CHANNEL="debug"` instead or omit `CHANNEL="release"` completely.
+This will implicitly build cg_clif too. Both `y.rs build` and `test.sh` accept a `--debug` argument to
+build in debug mode.
 
-### Rustc
+Alternatively you can download a pre built version from [GHA]. It is listed in the artifacts section
+of workflow runs. Unfortunately due to GHA restrictions you need to be logged in to access it.
 
-> You should prefer using the Cargo method.
+[GHA]: https://github.com/bjorn3/rustc_codegen_cranelift/actions?query=branch%3Amaster+event%3Apush+is%3Asuccess
+
+## Usage
+
+rustc_codegen_cranelift can be used as a near-drop-in replacement for `cargo build` or `cargo run` for existing projects.
+
+Assuming `$cg_clif_dir` is the directory you cloned this repo into and you followed the instructions (`y.rs prepare` and `y.rs build` or `test.sh`).
+
+In the directory with your project (where you can do the usual `cargo build`), run:
 
 ```bash
-$ rustc +$(cat $cg_clif_dir/rust-toolchain) -Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/release/librustc_codegen_cranelift.so --sysroot $cg_clif_dir/build_sysroot/sysroot my_crate.rs
+$ $cg_clif_dir/build/cargo build
 ```
 
-## Env vars
-
-<dl>
-    <dt>CG_CLIF_JIT</dt>
-    <dd>Enable JIT mode to immediately run a program instead of writing an executable file.</dd>
-    <dt>CG_CLIF_JIT_ARGS</dt>
-    <dd>When JIT mode is enable pass these arguments to the program.</dd>
-    <dt>CG_CLIF_INCR_CACHE_DISABLED</dt>
-    <dd>Don't cache object files in the incremental cache. Useful during development of cg_clif
-    to make it possible to use incremental mode for all analyses performed by rustc without caching
-    object files when their content should have been changed by a change to cg_clif.</dd>
-    <dt>CG_CLIF_DISPLAY_CG_TIME</dt>
-    <dd>Display the time it took to perform codegen for a crate</dd>
-</dl>
+This will build your project with rustc_codegen_cranelift instead of the usual LLVM backend.
+
+For additional ways to use rustc_codegen_cranelift like the JIT mode see [usage.md](docs/usage.md).
+
+## Configuration
+
+See the documentation on the `BackendConfig` struct in [config.rs](src/config.rs) for all
+configuration options.
 
 ## Not yet supported
 
-* Good non-rust abi support ([several problems](https://github.com/bjorn3/rustc_codegen_cranelift/issues/10))
-* Checked binops ([some missing instructions in cranelift](https://github.com/bytecodealliance/wasmtime/issues/1044))
-* Inline assembly ([no cranelift support](https://github.com/bytecodealliance/wasmtime/issues/1041), not coming soon)
+* Inline assembly ([no cranelift support](https://github.com/bytecodealliance/wasmtime/issues/1041))
+    * On Linux there is support for invoking an external assembler for `global_asm!` and `asm!`.
+      `llvm_asm!` will remain unimplemented forever. `asm!` doesn't yet support reg classes. You
+      have to specify specific registers instead.
 * SIMD ([tracked here](https://github.com/bjorn3/rustc_codegen_cranelift/issues/171), some basic things work)
+
+## License
+
+Licensed under either of
+
+  * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
+    http://www.apache.org/licenses/LICENSE-2.0)
+  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+    http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you shall be dual licensed as above, without any
+additional terms or conditions.