Try Rust PGO with wain project

pgo.sh

#!/bin/bash

set -e
set -x

cargo --version
rustc --version

executable=wain

llvm_profdata="${LLVM_PROFDATA_BIN:="llvm-profdata"}"
pgodir="${PROF_DIR:="$(pwd)/pgo-data"}"

rm -rf "$pgodir"
mkdir -p "$pgodir"

cargo clean

# `cargo rustc` only passes options to target crate but we want to pass options to all dependant crates
#   $ cargo rustc --verbose --release -- -Cprofile-generate="$pgodir"
CARGO_BUILD_RUSTFLAGS="-Cprofile-generate=${pgodir}" cargo build --verbose --release

wasm_files=(examples/*.{wasm,wat})

id=$((0))
for file in "${wasm_files[@]}"; do
    if [[ "$file" =~ guessing_game ]]; then
        # Skip because it requires interaction
        continue
    fi
    "./target/release/${executable}" "$file"
    ((id++))
done

$llvm_profdata merge -o "${pgodir}/merged.profdata" "$pgodir"

rm -f "${executable}-pgo" "${executable}-orig"

cargo clean

# `cargo rustc` only passes options to target crate but we want to pass options to all dependant crates
CARGO_BUILD_RUSTFLAGS="-Cprofile-use=${pgodir}/merged.profdata" cargo build --verbose --release
cp "./target/release/${executable}" "${executable}-pgo"

# For comparison
cargo clean
cargo build --verbose --release
cp "./target/release/${executable}" "${executable}-orig"

rm -f pgo_results.md
touch pgo_results.md
for file in "${wasm_files[@]}"; do
    if [[ "$file" =~ guessing_game ]]; then
        # Skip because it requires interaction
        continue
    fi
    hyperfine --export-markdown tmp.md "./${executable}-orig $file" "./${executable}-pgo $file"

    printf '\n### %s\n\n' "${file}" >> pgo_results.md
    cat tmp.md >> pgo_results.md
    rm -f tmp.md
done