Add regalloc2-tool (#148)

This PR has 2 components:
- A `SerializableFunction` which wraps a `Function` and `MachineEnv`.
This type can be serialized and deserialized with Serde, and is enabled
by the "enable-serde" feature.
- A `regalloc2-tool` binary which reads a bincode-encoded
`SerializableFunction` and then runs the register allocator and checker
on it.

This is a useful tool for debugging register allocation failures and to
investigate cases of poor register allocation.

Cargo.toml

@@ -1,3 +1,6 @@
+[workspace]
+members = ["regalloc2-tool"]
+
 [package]
 name = "regalloc2"
 version = "0.9.1"

deny.toml

@@ -10,15 +10,15 @@ targets = [
 vulnerability = "deny"
 unmaintained = "deny"
 yanked = "deny"
-ignore = [
-]
+ignore = []
 
 # https://embarkstudios.github.io/cargo-deny/checks/licenses/cfg.html
 [licenses]
 allow = [
     "Apache-2.0 WITH LLVM-exception",
     "Apache-2.0",
     "MIT",
+    "Unicode-DFS-2016",
 ]
 
 # https://embarkstudios.github.io/cargo-deny/checks/bans/cfg.html

regalloc2-tool/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "regalloc2-tool"
+authors = [
+    "Chris Fallin <chris@cfallin.org>",
+    "Mozilla SpiderMonkey Developers",
+]
+version = "0.0.0"
+edition = "2021"
+publish = false
+license = "Apache-2.0 WITH LLVM-exception"
+description = "Tool for testing regalloc2"
+repository = "https://github.com/bytecodealliance/regalloc2"
+
+[dependencies]
+bincode = "1.3.3"
+clap = { version = "4.3.11", features = ["derive"] }
+pretty_env_logger = "0.5.0"
+regalloc2 = { path = "..", features = ["trace-log", "enable-serde"] }

regalloc2-tool/src/main.rs

@@ -0,0 +1,95 @@
+use std::path::PathBuf;
+
+use clap::Parser;
+use regalloc2::{
+    checker::Checker, serialize::SerializableFunction, Block, Edit, Function, InstOrEdit, Output,
+    RegallocOptions,
+};
+
+#[derive(Parser)]
+/// Tool for testing regalloc2.
+struct Args {
+    /// Print the input function and the result of register allocation.
+    #[clap(short = 'v')]
+    verbose: bool,
+
+    /// Input file containing a bincode-encoded SerializedFunction.
+    input: PathBuf,
+}
+
+fn main() {
+    pretty_env_logger::init();
+    let args = Args::parse();
+
+    let input = std::fs::read(&args.input).expect("could not read input file");
+    let function: SerializableFunction =
+        bincode::deserialize(&input).expect("could not deserialize input file");
+
+    if args.verbose {
+        println!("Input function: {function:?}");
+    }
+
+    let options = RegallocOptions {
+        verbose_log: true,
+        validate_ssa: true,
+    };
+    let output = match regalloc2::run(&function, function.machine_env(), &options) {
+        Ok(output) => output,
+        Err(e) => {
+            panic!("Register allocation failed: {e:#?}");
+        }
+    };
+
+    if args.verbose {
+        print_output(&function, &output);
+    }
+
+    let mut checker = Checker::new(&function, function.machine_env());
+    checker.prepare(&output);
+    if let Err(e) = checker.run() {
+        panic!("Regsiter allocation checker failed: {e:#?}");
+    }
+}
+
+fn print_output(func: &SerializableFunction, output: &Output) {
+    print!("Register allocation result: {{\n");
+    for i in 0..func.num_blocks() {
+        let block = Block::new(i);
+        let succs = func
+            .block_succs(block)
+            .iter()
+            .map(|b| b.index())
+            .collect::<Vec<_>>();
+        let preds = func
+            .block_preds(block)
+            .iter()
+            .map(|b| b.index())
+            .collect::<Vec<_>>();
+        print!("  block{}: # succs:{:?} preds:{:?}\n", i, succs, preds);
+        for inst_or_edit in output.block_insts_and_edits(func, block) {
+            match inst_or_edit {
+                InstOrEdit::Inst(inst) => {
+                    let op = if func.is_ret(inst) {
+                        "ret"
+                    } else if func.is_branch(inst) {
+                        "branch"
+                    } else {
+                        "op"
+                    };
+                    let ops: Vec<_> = func
+                        .inst_operands(inst)
+                        .iter()
+                        .zip(output.inst_allocs(inst))
+                        .map(|(op, alloc)| format!("{op} => {alloc}"))
+                        .collect();
+                    let ops = ops.join(", ");
+                    print!("    inst{}: {op} {ops}\n", inst.index(),);
+                }
+                InstOrEdit::Edit(Edit::Move { from, to }) => {
+                    print!("    edit: move {to} <- {from}\n");
+                }
+            }
+        }
+    }
+    print!("}}\n");
+}

src/index.rs

@@ -137,6 +137,10 @@ define_index!(Inst);
 define_index!(Block);
 
 #[derive(Clone, Copy, Debug)]
+#[cfg_attr(
+    feature = "enable-serde",
+    derive(::serde::Serialize, ::serde::Deserialize)
+)]
 pub struct InstRange(Inst, Inst, bool);
 
 impl InstRange {

src/lib.rs

@@ -58,6 +58,9 @@ pub mod checker;
 #[cfg(feature = "fuzzing")]
 pub mod fuzzing;
 
+#[cfg(feature = "enable-serde")]
+pub mod serialize;
+
 #[cfg(feature = "enable-serde")]
 use serde::{Deserialize, Serialize};