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Diffstat (limited to 'ctr-std/src/sys/horizon/backtrace/mod.rs')
| -rw-r--r-- | ctr-std/src/sys/horizon/backtrace/mod.rs | 119 |
1 files changed, 0 insertions, 119 deletions
diff --git a/ctr-std/src/sys/horizon/backtrace/mod.rs b/ctr-std/src/sys/horizon/backtrace/mod.rs deleted file mode 100644 index b5bf20c..0000000 --- a/ctr-std/src/sys/horizon/backtrace/mod.rs +++ /dev/null @@ -1,119 +0,0 @@ -// Copyright 2015 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or -// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license -// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -/// Backtrace support built on libgcc with some extra OS-specific support -/// -/// Some methods of getting a backtrace: -/// -/// * The backtrace() functions on unix. It turns out this doesn't work very -/// well for green threads on macOS, and the address to symbol portion of it -/// suffers problems that are described below. -/// -/// * Using libunwind. This is more difficult than it sounds because libunwind -/// isn't installed everywhere by default. It's also a bit of a hefty library, -/// so possibly not the best option. When testing, libunwind was excellent at -/// getting both accurate backtraces and accurate symbols across platforms. -/// This route was not chosen in favor of the next option, however. -/// -/// * We're already using libgcc_s for exceptions in rust (triggering thread -/// unwinding and running destructors on the stack), and it turns out that it -/// conveniently comes with a function that also gives us a backtrace. All of -/// these functions look like _Unwind_*, but it's not quite the full -/// repertoire of the libunwind API. Due to it already being in use, this was -/// the chosen route of getting a backtrace. -/// -/// After choosing libgcc_s for backtraces, the sad part is that it will only -/// give us a stack trace of instruction pointers. Thankfully these instruction -/// pointers are accurate (they work for green and native threads), but it's -/// then up to us again to figure out how to translate these addresses to -/// symbols. As with before, we have a few options. Before, that, a little bit -/// of an interlude about symbols. This is my very limited knowledge about -/// symbol tables, and this information is likely slightly wrong, but the -/// general idea should be correct. -/// -/// When talking about symbols, it's helpful to know a few things about where -/// symbols are located. Some symbols are located in the dynamic symbol table -/// of the executable which in theory means that they're available for dynamic -/// linking and lookup. Other symbols end up only in the local symbol table of -/// the file. This loosely corresponds to pub and priv functions in Rust. -/// -/// Armed with this knowledge, we know that our solution for address to symbol -/// translation will need to consult both the local and dynamic symbol tables. -/// With that in mind, here's our options of translating an address to -/// a symbol. -/// -/// * Use dladdr(). The original backtrace()-based idea actually uses dladdr() -/// behind the scenes to translate, and this is why backtrace() was not used. -/// Conveniently, this method works fantastically on macOS. It appears dladdr() -/// uses magic to consult the local symbol table, or we're putting everything -/// in the dynamic symbol table anyway. Regardless, for macOS, this is the -/// method used for translation. It's provided by the system and easy to do.o -/// -/// Sadly, all other systems have a dladdr() implementation that does not -/// consult the local symbol table. This means that most functions are blank -/// because they don't have symbols. This means that we need another solution. -/// -/// * Use unw_get_proc_name(). This is part of the libunwind api (not the -/// libgcc_s version of the libunwind api), but involves taking a dependency -/// to libunwind. We may pursue this route in the future if we bundle -/// libunwind, but libunwind was unwieldy enough that it was not chosen at -/// this time to provide this functionality. -/// -/// * Shell out to a utility like `readelf`. Crazy though it may sound, it's a -/// semi-reasonable solution. The stdlib already knows how to spawn processes, -/// so in theory it could invoke readelf, parse the output, and consult the -/// local/dynamic symbol tables from there. This ended up not getting chosen -/// due to the craziness of the idea plus the advent of the next option. -/// -/// * Use `libbacktrace`. It turns out that this is a small library bundled in -/// the gcc repository which provides backtrace and symbol translation -/// functionality. All we really need from it is the backtrace functionality, -/// and we only really need this on everything that's not macOS, so this is the -/// chosen route for now. -/// -/// In summary, the current situation uses libgcc_s to get a trace of stack -/// pointers, and we use dladdr() or libbacktrace to translate these addresses -/// to symbols. This is a bit of a hokey implementation as-is, but it works for -/// all unix platforms we support right now, so it at least gets the job done. - -pub use self::tracing::unwind_backtrace; -pub use self::printing::{foreach_symbol_fileline, resolve_symname}; - -// tracing impls: -mod tracing; -// symbol resolvers: -mod printing; - -#[cfg(not(target_os = "emscripten"))] -pub mod gnu { - use io; - use fs; - use libc::c_char; - - #[cfg(not(any(target_os = "macos", target_os = "ios")))] - pub fn get_executable_filename() -> io::Result<(Vec<c_char>, fs::File)> { - Err(io::Error::new(io::ErrorKind::Other, "Not implemented")) - } - - #[cfg(any(target_os = "macos", target_os = "ios"))] - pub fn get_executable_filename() -> io::Result<(Vec<c_char>, fs::File)> { - use env; - use os::unix::ffi::OsStrExt; - - let filename = env::current_exe()?; - let file = fs::File::open(&filename)?; - let mut filename_cstr: Vec<_> = filename.as_os_str().as_bytes().iter() - .map(|&x| x as c_char).collect(); - filename_cstr.push(0); // Null terminate - Ok((filename_cstr, file)) - } -} - -pub struct BacktraceContext; |