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Diffstat (limited to 'vendor/rustc-demangle/src/legacy.rs')
| -rw-r--r-- | vendor/rustc-demangle/src/legacy.rs | 392 |
1 files changed, 392 insertions, 0 deletions
diff --git a/vendor/rustc-demangle/src/legacy.rs b/vendor/rustc-demangle/src/legacy.rs new file mode 100644 index 000000000..d55f3a1fd --- /dev/null +++ b/vendor/rustc-demangle/src/legacy.rs @@ -0,0 +1,392 @@ +use core::char; +use core::fmt; + +/// Representation of a demangled symbol name. +pub struct Demangle<'a> { + inner: &'a str, + /// The number of ::-separated elements in the original name. + elements: usize, +} + +/// De-mangles a Rust symbol into a more readable version +/// +/// All Rust symbols by default are mangled as they contain characters that +/// cannot be represented in all object files. The mangling mechanism is similar +/// to C++'s, but Rust has a few specifics to handle items like lifetimes in +/// symbols. +/// +/// This function will take a **mangled** symbol and return a value. When printed, +/// the de-mangled version will be written. If the symbol does not look like +/// a mangled symbol, the original value will be written instead. +/// +/// # Examples +/// +/// ``` +/// use rustc_demangle::demangle; +/// +/// assert_eq!(demangle("_ZN4testE").to_string(), "test"); +/// assert_eq!(demangle("_ZN3foo3barE").to_string(), "foo::bar"); +/// assert_eq!(demangle("foo").to_string(), "foo"); +/// ``` + +// All Rust symbols are in theory lists of "::"-separated identifiers. Some +// assemblers, however, can't handle these characters in symbol names. To get +// around this, we use C++-style mangling. The mangling method is: +// +// 1. Prefix the symbol with "_ZN" +// 2. For each element of the path, emit the length plus the element +// 3. End the path with "E" +// +// For example, "_ZN4testE" => "test" and "_ZN3foo3barE" => "foo::bar". +// +// We're the ones printing our backtraces, so we can't rely on anything else to +// demangle our symbols. It's *much* nicer to look at demangled symbols, so +// this function is implemented to give us nice pretty output. +// +// Note that this demangler isn't quite as fancy as it could be. We have lots +// of other information in our symbols like hashes, version, type information, +// etc. Additionally, this doesn't handle glue symbols at all. +pub fn demangle(s: &str) -> Result<(Demangle, &str), ()> { + // First validate the symbol. If it doesn't look like anything we're + // expecting, we just print it literally. Note that we must handle non-Rust + // symbols because we could have any function in the backtrace. + let inner = if s.starts_with("_ZN") { + &s[3..] + } else if s.starts_with("ZN") { + // On Windows, dbghelp strips leading underscores, so we accept "ZN...E" + // form too. + &s[2..] + } else if s.starts_with("__ZN") { + // On OSX, symbols are prefixed with an extra _ + &s[4..] + } else { + return Err(()); + }; + + // only work with ascii text + if inner.bytes().any(|c| c & 0x80 != 0) { + return Err(()); + } + + let mut elements = 0; + let mut chars = inner.chars(); + let mut c = chars.next().ok_or(())?; + while c != 'E' { + // Decode an identifier element's length. + if !c.is_digit(10) { + return Err(()); + } + let mut len = 0usize; + while let Some(d) = c.to_digit(10) { + len = len + .checked_mul(10) + .and_then(|len| len.checked_add(d as usize)) + .ok_or(())?; + c = chars.next().ok_or(())?; + } + + // `c` already contains the first character of this identifier, skip it and + // all the other characters of this identifier, to reach the next element. + for _ in 0..len { + c = chars.next().ok_or(())?; + } + + elements += 1; + } + + Ok((Demangle { inner, elements }, chars.as_str())) +} + +// Rust hashes are hex digits with an `h` prepended. +fn is_rust_hash(s: &str) -> bool { + s.starts_with('h') && s[1..].chars().all(|c| c.is_digit(16)) +} + +impl<'a> fmt::Display for Demangle<'a> { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + // Alright, let's do this. + let mut inner = self.inner; + for element in 0..self.elements { + let mut rest = inner; + while rest.chars().next().unwrap().is_digit(10) { + rest = &rest[1..]; + } + let i: usize = inner[..(inner.len() - rest.len())].parse().unwrap(); + inner = &rest[i..]; + rest = &rest[..i]; + // Skip printing the hash if alternate formatting + // was requested. + if f.alternate() && element + 1 == self.elements && is_rust_hash(&rest) { + break; + } + if element != 0 { + f.write_str("::")?; + } + if rest.starts_with("_$") { + rest = &rest[1..]; + } + loop { + if rest.starts_with('.') { + if let Some('.') = rest[1..].chars().next() { + f.write_str("::")?; + rest = &rest[2..]; + } else { + f.write_str(".")?; + rest = &rest[1..]; + } + } else if rest.starts_with('$') { + let (escape, after_escape) = if let Some(end) = rest[1..].find('$') { + (&rest[1..=end], &rest[end + 2..]) + } else { + break; + }; + + // see src/librustc_codegen_utils/symbol_names/legacy.rs for these mappings + let unescaped = match escape { + "SP" => "@", + "BP" => "*", + "RF" => "&", + "LT" => "<", + "GT" => ">", + "LP" => "(", + "RP" => ")", + "C" => ",", + + _ => { + if escape.starts_with('u') { + let digits = &escape[1..]; + let all_lower_hex = digits.chars().all(|c| match c { + '0'..='9' | 'a'..='f' => true, + _ => false, + }); + let c = u32::from_str_radix(digits, 16) + .ok() + .and_then(char::from_u32); + if let (true, Some(c)) = (all_lower_hex, c) { + // FIXME(eddyb) do we need to filter out control codepoints? + if !c.is_control() { + c.fmt(f)?; + rest = after_escape; + continue; + } + } + } + break; + } + }; + f.write_str(unescaped)?; + rest = after_escape; + } else if let Some(i) = rest.find(|c| c == '$' || c == '.') { + f.write_str(&rest[..i])?; + rest = &rest[i..]; + } else { + break; + } + } + f.write_str(rest)?; + } + + Ok(()) + } +} + +#[cfg(test)] +mod tests { + use std::prelude::v1::*; + + macro_rules! t { + ($a:expr, $b:expr) => { + assert!(ok($a, $b)) + }; + } + + macro_rules! t_err { + ($a:expr) => { + assert!(ok_err($a)) + }; + } + + macro_rules! t_nohash { + ($a:expr, $b:expr) => {{ + assert_eq!(format!("{:#}", ::demangle($a)), $b); + }}; + } + + fn ok(sym: &str, expected: &str) -> bool { + match ::try_demangle(sym) { + Ok(s) => { + if s.to_string() == expected { + true + } else { + println!("\n{}\n!=\n{}\n", s, expected); + false + } + } + Err(_) => { + println!("error demangling"); + false + } + } + } + + fn ok_err(sym: &str) -> bool { + match ::try_demangle(sym) { + Ok(_) => { + println!("succeeded in demangling"); + false + } + Err(_) => ::demangle(sym).to_string() == sym, + } + } + + #[test] + fn demangle() { + t_err!("test"); + t!("_ZN4testE", "test"); + t_err!("_ZN4test"); + t!("_ZN4test1a2bcE", "test::a::bc"); + } + + #[test] + fn demangle_dollars() { + t!("_ZN4$RP$E", ")"); + t!("_ZN8$RF$testE", "&test"); + t!("_ZN8$BP$test4foobE", "*test::foob"); + t!("_ZN9$u20$test4foobE", " test::foob"); + t!("_ZN35Bar$LT$$u5b$u32$u3b$$u20$4$u5d$$GT$E", "Bar<[u32; 4]>"); + } + + #[test] + fn demangle_many_dollars() { + t!("_ZN13test$u20$test4foobE", "test test::foob"); + t!("_ZN12test$BP$test4foobE", "test*test::foob"); + } + + #[test] + fn demangle_osx() { + t!( + "__ZN5alloc9allocator6Layout9for_value17h02a996811f781011E", + "alloc::allocator::Layout::for_value::h02a996811f781011" + ); + t!("__ZN38_$LT$core..option..Option$LT$T$GT$$GT$6unwrap18_MSG_FILE_LINE_COL17haf7cb8d5824ee659E", "<core::option::Option<T>>::unwrap::_MSG_FILE_LINE_COL::haf7cb8d5824ee659"); + t!("__ZN4core5slice89_$LT$impl$u20$core..iter..traits..IntoIterator$u20$for$u20$$RF$$u27$a$u20$$u5b$T$u5d$$GT$9into_iter17h450e234d27262170E", "core::slice::<impl core::iter::traits::IntoIterator for &'a [T]>::into_iter::h450e234d27262170"); + } + + #[test] + fn demangle_windows() { + t!("ZN4testE", "test"); + t!("ZN13test$u20$test4foobE", "test test::foob"); + t!("ZN12test$RF$test4foobE", "test&test::foob"); + } + + #[test] + fn demangle_elements_beginning_with_underscore() { + t!("_ZN13_$LT$test$GT$E", "<test>"); + t!("_ZN28_$u7b$$u7b$closure$u7d$$u7d$E", "{{closure}}"); + t!("_ZN15__STATIC_FMTSTRE", "__STATIC_FMTSTR"); + } + + #[test] + fn demangle_trait_impls() { + t!( + "_ZN71_$LT$Test$u20$$u2b$$u20$$u27$static$u20$as$u20$foo..Bar$LT$Test$GT$$GT$3barE", + "<Test + 'static as foo::Bar<Test>>::bar" + ); + } + + #[test] + fn demangle_without_hash() { + let s = "_ZN3foo17h05af221e174051e9E"; + t!(s, "foo::h05af221e174051e9"); + t_nohash!(s, "foo"); + } + + #[test] + fn demangle_without_hash_edgecases() { + // One element, no hash. + t_nohash!("_ZN3fooE", "foo"); + // Two elements, no hash. + t_nohash!("_ZN3foo3barE", "foo::bar"); + // Longer-than-normal hash. + t_nohash!("_ZN3foo20h05af221e174051e9abcE", "foo"); + // Shorter-than-normal hash. + t_nohash!("_ZN3foo5h05afE", "foo"); + // Valid hash, but not at the end. + t_nohash!("_ZN17h05af221e174051e93fooE", "h05af221e174051e9::foo"); + // Not a valid hash, missing the 'h'. + t_nohash!("_ZN3foo16ffaf221e174051e9E", "foo::ffaf221e174051e9"); + // Not a valid hash, has a non-hex-digit. + t_nohash!("_ZN3foo17hg5af221e174051e9E", "foo::hg5af221e174051e9"); + } + + #[test] + fn demangle_thinlto() { + // One element, no hash. + t!("_ZN3fooE.llvm.9D1C9369", "foo"); + t!("_ZN3fooE.llvm.9D1C9369@@16", "foo"); + t_nohash!( + "_ZN9backtrace3foo17hbb467fcdaea5d79bE.llvm.A5310EB9", + "backtrace::foo" + ); + } + + #[test] + fn demangle_llvm_ir_branch_labels() { + t!("_ZN4core5slice77_$LT$impl$u20$core..ops..index..IndexMut$LT$I$GT$$u20$for$u20$$u5b$T$u5d$$GT$9index_mut17haf9727c2edfbc47bE.exit.i.i", "core::slice::<impl core::ops::index::IndexMut<I> for [T]>::index_mut::haf9727c2edfbc47b.exit.i.i"); + t_nohash!("_ZN4core5slice77_$LT$impl$u20$core..ops..index..IndexMut$LT$I$GT$$u20$for$u20$$u5b$T$u5d$$GT$9index_mut17haf9727c2edfbc47bE.exit.i.i", "core::slice::<impl core::ops::index::IndexMut<I> for [T]>::index_mut.exit.i.i"); + } + + #[test] + fn demangle_ignores_suffix_that_doesnt_look_like_a_symbol() { + t_err!("_ZN3fooE.llvm moocow"); + } + + #[test] + fn dont_panic() { + ::demangle("_ZN2222222222222222222222EE").to_string(); + ::demangle("_ZN5*70527e27.ll34csaғE").to_string(); + ::demangle("_ZN5*70527a54.ll34_$b.1E").to_string(); + ::demangle( + "\ + _ZN5~saäb4e\n\ + 2734cOsbE\n\ + 5usage20h)3\0\0\0\0\0\0\07e2734cOsbE\ + ", + ) + .to_string(); + } + + #[test] + fn invalid_no_chop() { + t_err!("_ZNfooE"); + } + + #[test] + fn handle_assoc_types() { + t!("_ZN151_$LT$alloc..boxed..Box$LT$alloc..boxed..FnBox$LT$A$C$$u20$Output$u3d$R$GT$$u20$$u2b$$u20$$u27$a$GT$$u20$as$u20$core..ops..function..FnOnce$LT$A$GT$$GT$9call_once17h69e8f44b3723e1caE", "<alloc::boxed::Box<alloc::boxed::FnBox<A, Output=R> + 'a> as core::ops::function::FnOnce<A>>::call_once::h69e8f44b3723e1ca"); + } + + #[test] + fn handle_bang() { + t!( + "_ZN88_$LT$core..result..Result$LT$$u21$$C$$u20$E$GT$$u20$as$u20$std..process..Termination$GT$6report17hfc41d0da4a40b3e8E", + "<core::result::Result<!, E> as std::process::Termination>::report::hfc41d0da4a40b3e8" + ); + } + + #[test] + fn demangle_utf8_idents() { + t_nohash!( + "_ZN11utf8_idents157_$u10e1$$u10d0$$u10ed$$u10db$$u10d4$$u10da$$u10d0$$u10d3$_$u10d2$$u10d4$$u10db$$u10e0$$u10d8$$u10d4$$u10da$$u10d8$_$u10e1$$u10d0$$u10d3$$u10d8$$u10da$$u10d8$17h21634fd5714000aaE", + "utf8_idents::საჭმელად_გემრიელი_სადილი" + ); + } + + #[test] + fn demangle_issue_60925() { + t_nohash!( + "_ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo17h059a991a004536adE", + "issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo" + ); + } +} |