Replace functions taking or returning u128 or i128 with a trap

[rust.git] / Readme.md

diff --git a/Readme.md b/Readme.md
index 7c1efe263f69ca1ec2938487aa3c83272b01d954..e6b6f68bfac1bcaec72f1d00728bffd4b3191891 100644 (file)
--- a/Readme.md
+++ b/Readme.md
@@ -1,70 +1,42 @@
 # Work in progress cranelift codegen backend for rust
 
-> ⚠⚠⚠ This doesn't do anything useful yet ⚠⚠⚠
+> ⚠⚠⚠ This doesn't do much useful yet ⚠⚠⚠
 
 ## Building
 
 ```bash
 $ git clone https://github.com/bjorn3/rustc_codegen_cranelift.git
 $ cd rustc_codegen_cranelift
-$ rustup override set nightly
-$ git submodule update --init
-$ cargo build
+$ ./prepare.sh # downloads and patches sysroot src and installs hyperfine for benchmarking
+$ ./test.sh
 ```
 
 ## Usage
 
+`$cg_clif_dir` is the directory you cloned this repo into in the following instruction.
+
+### Rustc
+
 ```bash
-$ rustc -Zcodegen-backend=$(pwd)/target/debug/librustc_codegen_cranelift.so my_crate.rs --crate-type lib -Og
+$ rustc -Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/debug/librustc_codegen_cranelift.so my_crate.rs
 ```
 
-> You must compile with `-Og`, because checked binops are not yet supported.
-
-## Building libcore
+### Cargo
 
 ```bash
-$ rustup component add rust-src
-$ ./prepare_libcore.sh
-$ ./build.sh
+$ RUSTFLAGS="-Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/debug/librustc_codegen_cranelift.dylib --sysroot $cg_clif_dir/build_sysroot/sysroot" cargo run
 ```
 
-> ⚠⚠⚠ You will get a panic because of unimplemented stuff ⚠⚠⚠
-
 ## Not yet supported
 
-* Checked binops
-* Statics
-* Drop glue
+* Good non-rust abi support ([scalar pair and vector are passed by-ref](https://github.com/bjorn3/rustc_codegen_cranelift/issues/10))
+* Checked binops ([some missing instructions in cranelift](https://github.com/CraneStation/cranelift/issues/460))
+* Inline assembly ([no cranelift support](https://github.com/CraneStation/cranelift/issues/444))
+* u128 and i128 ([no cranelift support](https://github.com/CraneStation/cranelift/issues/354))
+* SIMD ([tracked here](https://github.com/bjorn3/rustc_codegen_cranelift/issues/171))
 
-* Building libraries
-* Other call abi's
-* Unsized types
-* Slice indexing
-* Sub slice
-* Some rvalue's
+## Troubleshooting
 
-* Inline assembly
-* Custom sections
+### Can't compile
 
-## Known errors
-
-* cranelift-module api seems to be used wrong, thus causing panic for some consts
-* cranelift-codegen doesn't have encodings for some instructions for types smaller than I32
-
-```
-[...]
-warning: DefId(0/0:128 ~ lib[8787]::f64[0]::{{impl}}[0]::classify[0]):
-fn f64::<impl at ./target/libcore/src/libcore/num/f64.rs:156:1: 490:2>::classify(_1: f64) -> num::FpCategory{
-[...]
-}
-warning: stmt _3 = _1
-warning: stmt _5 = BitAnd(move _6, const Unevaluated(DefId(0/0:130 ~ lib[8787]::f64[0]::{{impl}}[0]::classify[0]::MAN_MASK[0]), []):u64)
-thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', libcore/option.rs:345:21
-stack backtrace:
-[...]
-  10: <core::option::Option<T>>::unwrap
-             at /checkout/src/libcore/macros.rs:20
-  11: rustc_codegen_cranelift::constant::trans_constant
-             at src/constant.rs:26
-[...]
-```
+Try updating your nightly compiler. You can try to use an nightly a day or two older if updating rustc doesn't fix it. If you still can't compile it, please fill an issue.