Compile rustc using cg_clif #743
Comments
bjorn3
added
the
C-enhancement
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The problem is |
Filled cryptocorrosion/cryptocorrosion#25 for running without SIMD. |
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Pushed 6129921 with some fixes necessary for this. |
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Now there are two const_err's which don't make sense: |
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Marked as bug because of the impossible |
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I got rustc bootstrapping using cg_clif. Unfortunately the rustc built using cg_clif crashes when you try to use it. So far I have been able to pin point that Rust fork: bjorn3/rust@e5c3091 (branch cg_clif_subtree) config.toml: [rust]
codegen-backends = ["cranelift"]
deny-warnings = false |
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Rust fork: bjorn3/rust@42728c0 Edit config.toml: [build]
full-bootstrap = true
[rust]
codegen-backends = ["cranelift"]
deny-warnings = falseCurrent failure: |
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The ICE happens at https://github.com/bjorn3/rust/blob/42728c0730229daad922372f76e08f5e40c31aa1/src/librustc_mir_build/build/matches/test.rs#L227. I am probably handling matching on |
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Minimal repro for ICE: fn is_true(a: true) -> u8 {
if a { 1 } else { 0 }
} |
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Minimal miscompilation repro: fn main() {
let options = [1u128];
match options[0] {
1 => (),
0 => loop {},
v => panic(v),
};
}
fn panic(v: u128) -> !{
panic!("{}", v)
}clif ir for `main` |
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Got to metadata writing with the miscompilation fixed. It panicked in |
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It finally works! 🎉 🎈 🚀 🎈 🎉 Rust fork: bjorn3/rust@9a1facc Edit config.toml: [build]
full-bootstrap = true
[rust]
codegen-backends = ["cranelift"]
deny-warnings = false |
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bytecodealliance/wasmtime#1939 got merged. The only Cranelift blocker is now bytecodealliance/wasmtime#1559. |
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bytecodealliance/wasmtime#1559. has been merged. As of #1068 it is no longer necessary to patch cg_clif or Cranelift. |
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what's left for compiling rustc then? |
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With #1070 merged, only bjorn3/rust@3b4a3d6...9a1facc should be necessary now. |
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I rebased and cleaned up the rust branch (now called
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I’m curious - how much longer are those times with llvm? |
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Stage 0 is using a cg_llvm compiled rustc with cg_llvm as backend. This is representative for all stages when using cg_llvm. Stage 1 is using a cg_llvm compiled rustc with cg_clif as backend. Stage 2 is using a cg_clif compiled rustc with cg_clif as backend. The difference between stage 0 and stage 1 is the compile time speedup of cg_clif over release mode cg_llvm. The difference between stage 1 and stage 2 is the runtime slowdown of cg_clif over release mode cg_llvm. This difference is much less when using cg_llvm in debug mode. I don't volunteer for testing the difference between cg_clif and debug mode cg_llvm as it would take me ~4-5h, during which I can't use my computer at all. :) |
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Brilliant - thank you for the explanation! Incredible results. |
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@bjorn3 in stage 0, are you re-compiling llvm from scratch or do you have it cached? IIRC it's compiled only once for all three stages so to give a fair comparison between cg_llvm and cg_clif, one needs to ensure it's not compiled during the stage 0 build but cached. |
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I didn't compile LLVM at all. Stage 0 is the compilation of a rustc that only supports cg_clif using the bootstrap compiler. |
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@vultix On reddit you said 7x faster. This is pretty much comparing apples to oranges. cg_clif compiles code that runs a bit slower than debug mode cg_llvm. The compilation of rustc was however with release mode cg_llvm. This seems to have caused a bit of confusion on reddit. |
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@bjorn3 amazing! |
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Ah, my apologies for confusing everyone. That distinction never occurred to me |
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After #78624 all you need to do is apply diff --git a/compiler/rustc_data_structures/Cargo.toml b/compiler/rustc_data_structures/Cargo.toml
index 23e689fcae7..5f077b765b6 100644
--- a/compiler/rustc_data_structures/Cargo.toml
+++ b/compiler/rustc_data_structures/Cargo.toml
@@ -32,7 +32,7 @@ tempfile = "3.0.5"
[dependencies.parking_lot]
version = "0.11"
-features = ["nightly"]
+#features = ["nightly"]
[target.'cfg(windows)'.dependencies]
winapi = { version = "0.3", features = ["fileapi", "psapi"] }and run $ cat > config.toml <<EOF
[build]
full-bootstrap = true
[rust]
codegen-backends = ["cranelift"]
EOF
$ ./x.py build --stage 2 |
…=jyn514 Sync rustc_codegen_cranelift This fixes bootstrapping of rustc using cg_clif again. It regressed a while before rust-lang#77975 got merged. Fixes https://github.com/bjorn3/rustc_codegen_cranelift/issues/743
…=jyn514 Sync rustc_codegen_cranelift This fixes bootstrapping of rustc using cg_clif again. It regressed a while before rust-lang#77975 got merged. Fixes https://github.com/bjorn3/rustc_codegen_cranelift/issues/743
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Fixed in https://github.com/bjorn3/rustc_codegen_cranelift/pull/1099 and added a test in bjorn3@54b1d10. |
Currently fails while compiling libcore using the new compiler with:
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