$ cargo install cargo-show-asm

Show the code rustc generates for any function

Usage: [-p SPEC] [--lib | --test TEST | --bench BENCH | --example EXAMPLE | --bin BIN] [--release |
--dev | --profile PROFILE] [--target TRIPLE] -C FLAG... -Z FLAG... [--native | --target-cpu CPU]
[--rust] [--simplify] -M ARG... [--intel | --att | --llvm | --llvm-input | --mir | --wasm |
--mca-intel | --mca-att] [--everything | <ITEM_INDEX> | <FUNCTION> [<INDEX>]]

Usage:
  1. Focus on a single assembly producing target:
     % cargo asm -p isin --lib   # here we are targeting lib in isin crate
  2. Narrow down a function:
     % cargo asm -p isin --lib from_ # here "from_" is part of the function you are interested intel
  3. Get the full results:
     % cargo asm -p isin --lib isin::base36::from_alphanum

Available positional items:
    <ITEM_INDEX>  Dump name with this index
    <FUNCTION>    Dump function with that specific name / filter functions containing this string
    <INDEX>       Select specific function when there's several with the same name

Available options:
    -p, --package <SPEC>  Package to use, defaults to a current one, required for workspace projects,
                          can also point to a dependency
        --lib             Show results from library code
        --test <TEST>     Show results from an integration test
        --bench <BENCH>   Show results from a benchmark
        --example <EXAMPLE>  Show results from an example
        --bin <BIN>       Show results from a binary
        --manifest-path <PATH>  Path to Cargo.toml, defaults to one in current folder
        --target-dir <DIR>  [env:CARGO_TARGET_DIR: N/A]
                          Use custom target directory for generated artifacts, create if missing
        --dry             Produce a build plan instead of actually building
        --frozen          Requires Cargo.lock and cache are up to date
        --locked          Requires Cargo.lock is up to date
        --offline         Run without accessing the network
        --no-default-features  Do not activate `default` feature
        --all-features    Activate all available features
        --features <FEATURE>  A feature to activate, can be used multiple times
        --release         Compile in release mode (default)
        --dev             Compile in dev mode
        --profile <PROFILE>  Build for this specific profile
        --target <TRIPLE>  Build for the target triple
    -C <FLAG>             Codegen flags to rustc, see 'rustc -C help' for details
    -Z <FLAG>             Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details
        --native          Optimize for the CPU running the compiler
        --target-cpu <CPU>  Optimize code for a specific CPU, see 'rustc --print target-cpus'
        --rust            Print interleaved Rust code
        --color           Enable color highlighting
        --no-color        Disable color highlighting
        --full-name       Include full demangled name instead of just prefix
        --keep-labels     Keep all the original labels
    -v, --verbose         more verbose output, can be specified multiple times
        --simplify        Try to strip some of the non-assembly instruction information
    -M, --mca-arg <ARG>   Pass parameter to llvm-mca for mca targets
        --intel           Show assembly using Intel style
        --att             Show assembly using AT&T style
        --llvm            Show llvm-ir
        --llvm-input      Show llvm-ir before any LLVM passes
        --mir             Show MIR
        --wasm            Show WASM, needs wasm32-unknown-unknown target installed
        --mca-intel       Show llvm-mca analysis, Intel style asm
        --mca-att         Show llvm-mca analysis, AT&T style asm
        --everything      Dump the whole asm file
    -h, --help            Prints help information
    -V, --version         Prints version information

$ cargo asm --lib
Try one of those
"<&T as core::fmt::Display>::fmt" [17, 12, 12, 12, 12, 19, 19, 12]
"<&mut W as core::fmt::Write>::write_char" [20]
"<&mut W as core::fmt::Write>::write_fmt" [38]
"<&mut W as core::fmt::Write>::write_str" [90]
"<F as nom::internal::Parser<I,O,E>>::parse" [263]
# ...

$ cargo asm --lib "cargo_show_asm::opts::focus::{{closure}}"

$ cargo asm --lib "cargo_show_asm::opts::focus::{{closure}}" 2

$ cargo asm --lib --full-name
# ...
$ cargo asm --lib "once_cell::imp::OnceCell<T>::initialize::h9c5c7d5bd745000b"

$ cargo asm --lib Debug

$ cargo-asm --bpaf-complete-style-bash
$ cargo-asm --bpaf-complete-style-zsh
$ cargo-asm --bpaf-complete-style-fish
$ cargo-asm --bpaf-complete-style-elvish

cargo install cargo-show-asm -F bright-color
cargo install cargo-show-asm -F dull-color