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> I suppose this is the end of the dive, unless someone knows some tools to get more insight into .rodata data. I suppose in theory it should be possible to tra

> I suppose this is the end of the dive, unless someone knows some tools to get more insight into .rodata data. I suppose in theory it should be possible to track down where in the code each bit of .rodata is accessed from, but that seems bit of a stretch. My tool Bloaty (https://github.com/google/bloaty https://github.com/google/bloaty) attempts to do exactly this. It even disassembles the binary looking for instructions that reference other sections like .rodata. It doesn't currently know anything about Rust's name mangling scheme. I'd be happy to add this, though I suppose Rust's mangling is probably written in Rust and Bloaty is written in C++.

Serow225 9y ago
That looks like a very cool tool, thanks for sharing! Bookmarked :)
mnemonik 9y ago
GNU libiberty includes a Rust symbol demangler that you can link: https://github.com/gcc-mirror/gcc/blob/master/libiberty/rust-demangle.c https://github.com/gcc-mirror/gcc/blob/master/libiberty/rust...
zokier 9y ago
Cool. So I ran bloaty (with -d sections,segments,rawsymbols) on tinyrocket and used rustfilt[1] to demangle the symbols, and we have numbers for .rodata: demangled Filesize (KiB) idna::uts46::find_char 89.25 unicode_normalization::normalize::d 69.52 [384 Others] 43.48 rocket::config::RocketConfig::override_from_env 23.59 unicode_bidi::char_data::bidi_class 15.16 idna::uts46::decode_slice 12.23 unicode_normalization::normalize::compose 10.29 core::num::dec2flt::algorithm::power_of_ten 5.97 unicode_normalization::tables::normalization::canonical_comb 3.91 [section .rodata] 1.99 idna::uts46::validate 1.95 <hyper::status::StatusCode as core::fmt::Debug>::fmt 1.79 tinyrocket::main 1.46 core::num::flt2dec::strategy::grisu::CACHED_POW10 1.27 rocket::config::config::Config::set_raw 1.15 time::display::parse_type 0.99 hyper::server::listener::spawn_with::{{closure}} 0.96 percent_encoding::percent_encode_byte 0.76 <hyper::status::StatusCode as core::fmt::Display>::fmt 0.71 rocket::catcher::defaults::get::handle_431 0.66 rocket::config::init::{{closure}} 0.65 Lots of unicode and idna stuff there. I think the binary size would be reduced significantly if we could drop those somehow. Most likely those embedded HTML (error) pages are accounted in "rocket::config::RocketConfig::override_from_env", which sort of makes sense. > It doesn't currently know anything about Rust's name mangling scheme. I'd be happy to add this, though I suppose Rust's mangling is probably written in Rust and Bloaty is written in C++. I suppose you don't want to have a (optional) dependency to Rust code? It should be pretty easy to provide C interface to rustc-demangle[2] which would be usable from Bloaty. [1] https://github.com/luser/rustfilt https://github.com/luser/rustfilt [2] https://github.com/alexcrichton/rustc-demangle https://github.com/alexcrichton/rustc-demangle
- mbrubeck 9y ago
  And if you are willing to depend on Rust code, there's also a C++ symbol demangler written in Rust... :) http://fitzgeraldnick.com/2017/02/22/cpp-demangle.html http://fitzgeraldnick.com/2017/02/22/cpp-demangle.html
- zokier 9y ago
  This was easier than I thought: https://github.com/google/bloaty/compare/master...zokier:rust_demangle?expand=1 https://github.com/google/bloaty/compare/master...zokier:rus... and here is the wrapper for rustc-demangle: https://github.com/zokier/rust-demangle-clib https://github.com/zokier/rust-demangle-clib Seems to work just fine for my simple use at least: [zokier@zarch bloaty]$ ./bloaty -d sections,segments,symbols -C rust /tmp/tinyrocket/target/release/tinyrocket VM SIZE FILE SIZE -------------- -------------- 52.0% 506Ki .text 506Ki 24.8% 100.0% 506Ki LOAD [RX] 506Ki 100.0% 65.6% 332Ki [967 Others] 332Ki 65.6% 5.1% 25.7Ki hyper::server::listener::spawn_with::{{closure}} 25.7Ki 5.1% 3.6% 18.3Ki <yansi::Paint<T> as core::fmt::Display>::fmt 18.3Ki 3.6% 2.9% 14.5Ki rocket::ignite 14.5Ki 2.9% 2.5% 12.8Ki rocket::config::config::Config::set_raw 12.8Ki 2.5% 2.1% 10.7Ki core::ptr::drop_in_place 10.7Ki 2.1% 1.9% 9.78Ki std::sys_common::backtrace::output 9.78Ki 1.9% 1.9% 9.62Ki tinyrocket::main 9.62Ki 1.9% 1.6% 8.16Ki <alloc::raw_vec::RawVec<T, A>>::double 8.16Ki 1.6% ... I can try to clean it up bit more etc if you want a proper pull request for this?
  - haberman 9y ago

Serow225 9y ago

That looks like a very cool tool, thanks for sharing! Bookmarked :)

mnemonik 9y ago

GNU libiberty includes a Rust symbol demangler that you can link: https://github.com/gcc-mirror/gcc/blob/master/libiberty/rust-demangle.c https://github.com/gcc-mirror/gcc/blob/master/libiberty/rust...

zokier 9y ago

Cool. So I ran bloaty (with -d sections,segments,rawsymbols) on tinyrocket and used rustfilt[1] to demangle the symbols, and we have numbers for .rodata: demangled Filesize (KiB) idna::uts46::find_char 89.25 unicode_normalization::normalize::d 69.52 [384 Others] 43.48 rocket::config::RocketConfig::override_from_env 23.59 unicode_bidi::char_data::bidi_class 15.16 idna::uts46::decode_slice 12.23 unicode_normalization::normalize::compose 10.29 core::num::dec2flt::algorithm::power_of_ten 5.97 unicode_normalization::tables::normalization::canonical_comb 3.91 [section .rodata] 1.99 idna::uts46::validate 1.95 <hyper::status::StatusCode as core::fmt::Debug>::fmt 1.79 tinyrocket::main 1.46 core::num::flt2dec::strategy::grisu::CACHED_POW10 1.27 rocket::config::config::Config::set_raw 1.15 time::display::parse_type 0.99 hyper::server::listener::spawn_with::{{closure}} 0.96 percent_encoding::percent_encode_byte 0.76 <hyper::status::StatusCode as core::fmt::Display>::fmt 0.71 rocket::catcher::defaults::get::handle_431 0.66 rocket::config::init::{{closure}} 0.65 Lots of unicode and idna stuff there. I think the binary size would be reduced significantly if we could drop those somehow. Most likely those embedded HTML (error) pages are accounted in "rocket::config::RocketConfig::override_from_env", which sort of makes sense. > It doesn't currently know anything about Rust's name mangling scheme. I'd be happy to add this, though I suppose Rust's mangling is probably written in Rust and Bloaty is written in C++. I suppose you don't want to have a (optional) dependency to Rust code? It should be pretty easy to provide C interface to rustc-demangle[2] which would be usable from Bloaty. [1] https://github.com/luser/rustfilt https://github.com/luser/rustfilt [2] https://github.com/alexcrichton/rustc-demangle https://github.com/alexcrichton/rustc-demangle

mbrubeck 9y ago
And if you are willing to depend on Rust code, there's also a C++ symbol demangler written in Rust... :) http://fitzgeraldnick.com/2017/02/22/cpp-demangle.html http://fitzgeraldnick.com/2017/02/22/cpp-demangle.html
zokier 9y ago
This was easier than I thought: https://github.com/google/bloaty/compare/master...zokier:rust_demangle?expand=1 https://github.com/google/bloaty/compare/master...zokier:rus... and here is the wrapper for rustc-demangle: https://github.com/zokier/rust-demangle-clib https://github.com/zokier/rust-demangle-clib Seems to work just fine for my simple use at least: [zokier@zarch bloaty]$ ./bloaty -d sections,segments,symbols -C rust /tmp/tinyrocket/target/release/tinyrocket VM SIZE FILE SIZE -------------- -------------- 52.0% 506Ki .text 506Ki 24.8% 100.0% 506Ki LOAD [RX] 506Ki 100.0% 65.6% 332Ki [967 Others] 332Ki 65.6% 5.1% 25.7Ki hyper::server::listener::spawn_with::{{closure}} 25.7Ki 5.1% 3.6% 18.3Ki <yansi::Paint<T> as core::fmt::Display>::fmt 18.3Ki 3.6% 2.9% 14.5Ki rocket::ignite 14.5Ki 2.9% 2.5% 12.8Ki rocket::config::config::Config::set_raw 12.8Ki 2.5% 2.1% 10.7Ki core::ptr::drop_in_place 10.7Ki 2.1% 1.9% 9.78Ki std::sys_common::backtrace::output 9.78Ki 1.9% 1.9% 9.62Ki tinyrocket::main 9.62Ki 1.9% 1.6% 8.16Ki <alloc::raw_vec::RawVec<T, A>>::double 8.16Ki 1.6% ... I can try to clean it up bit more etc if you want a proper pull request for this?
- haberman 9y ago