Micro-optimize code size of /proc/maps parsing code

The current code size is really wastefully large. Originally, it was
1500 lines of assembly in Godbolt, now I reduced it to just under 800.
The effect of `.text` size in hello world is from 297028 to 295453 which
is small but not completely irrelevant. It's just a small fish in the
bigger pond of DWARF parsing, but it's better than nothing.

I extracted the parsing of each component into a separate function to
allow for better sharing. I replaced the string methods with manual
iteration since that results in simpler code because it has to handle
fewer cases. I also had to use unsafe because the bounds checks were
sadly not optimized out and were really large.

I also made the parser less resilient against whitespace, now it no
longer handles Unicode whitespace (an obvious simplification) but also
no longer handles any whitespace except the normal SP. I think this is
fine, it seems highly unlikely that a system would suddenly use another
type of whitespace (but I guess not impossible?).
1 file changed
tree: 41d5512d244e40f1e2ab36e5b6f7a39b5fb8b205
  1. .github/
  2. benches/
  3. ci/
  4. crates/
  5. examples/
  6. src/
  7. tests/
  8. .gitignore
  9. bindings.txt
  10. Cargo.lock
  11. Cargo.toml
  12. LICENSE-APACHE
  13. LICENSE-MIT
  14. README.md
README.md

backtrace-rs

Documentation

A library for acquiring backtraces at runtime for Rust. This library aims to enhance the support of the standard library by providing a programmatic interface to work with, but it also supports simply easily printing the current backtrace like libstd's panics.

Install

[dependencies]
backtrace = "0.3"

Usage

To simply capture a backtrace and defer dealing with it until a later time, you can use the top-level Backtrace type.

use backtrace::Backtrace;

fn main() {
    let bt = Backtrace::new();

    // do_some_work();

    println!("{bt:?}");
}

If, however, you'd like more raw access to the actual tracing functionality, you can use the trace and resolve functions directly.

fn main() {
    backtrace::trace(|frame| {
        let ip = frame.ip();
        let symbol_address = frame.symbol_address();

        // Resolve this instruction pointer to a symbol name
        backtrace::resolve_frame(frame, |symbol| {
            if let Some(name) = symbol.name() {
                // ...
            }
            if let Some(filename) = symbol.filename() {
                // ...
            }
        });

        true // keep going to the next frame
    });
}

Supported Rust Versions

The backtrace crate is a core component of the standard library, and must at times keep up with the evolution of various platforms in order to serve the standard library's needs. This often means using recent libraries that provide unwinding and symbolication for various platforms. Thus backtrace is likely to use recent Rust features or depend on a library which itself uses them. Its minimum supported Rust version, by policy, is within a few versions of current stable, approximately “stable - 2”.

This policy takes precedence over versions written anywhere else in this repo.

License

This project is licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in backtrace-rs by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.