cargo-llvm-lines

Count the number of lines of LLVM IR across all instantiations of a generic function. Based on a suggestion from @eddyb on how to count monomorphized functions in order to debug compiler memory usage, executable size and compile time.

<eddyb> unoptimized LLVM IR <eddyb> first used grep '^define' to get only the lines defining function bodies <eddyb> then regex replace in my editor to remove everything before @ and everything after ( <eddyb> then sort | uniq -c

Installation

Install with cargo install cargo-llvm-lines.

Output

One line per function with five columns of output:

1. Total number of lines of LLVM IR generated across all instantiations of the function (and the percentage of the total).
2. Number of instantiations of the function. For a generic function, roughly the number of distinct combinations of generic type parameters it is called with (and the percentage of the total).
3. Name of the function.

$ cargo llvm-lines | head -20

  Lines        Copies         Function name
  -----        ------         -------------
  30737 (100%)   1107 (100%)  (TOTAL)
   1395 (4.5%)     83 (7.5%)  core::ptr::drop_in_place
    760 (2.5%)      2 (0.2%)  alloc::slice::merge_sort
    734 (2.4%)      2 (0.2%)  alloc::raw_vec::RawVec<T,A>::reserve_internal
    666 (2.2%)      1 (0.1%)  cargo_llvm_lines::count_lines
    490 (1.6%)      1 (0.1%)  <std::process::Command as cargo_llvm_lines::PipeTo>::pipe_to
    476 (1.5%)      6 (0.5%)  core::result::Result<T,E>::map
    440 (1.4%)      1 (0.1%)  cargo_llvm_lines::read_llvm_ir
    422 (1.4%)      2 (0.2%)  alloc::slice::merge
    399 (1.3%)      4 (0.4%)  alloc::vec::Vec<T>::extend_desugared
    388 (1.3%)      2 (0.2%)  alloc::slice::insert_head
    366 (1.2%)      5 (0.5%)  core::option::Option<T>::map
    304 (1.0%)      6 (0.5%)  alloc::alloc::box_free
    296 (1.0%)      4 (0.4%)  core::result::Result<T,E>::map_err
    295 (1.0%)      1 (0.1%)  cargo_llvm_lines::wrap_args
    291 (0.9%)      1 (0.1%)  core::char::methods::<impl char>::encode_utf8
    286 (0.9%)      1 (0.1%)  cargo_llvm_lines::run_cargo_rustc
    284 (0.9%)      4 (0.4%)  core::option::Option<T>::ok_or_else

License