-
-// 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(writer: &mut dyn Write, mut s: &str, format: PrintFormat) -> io::Result<()> {
- // During ThinLTO LLVM may import and rename internal symbols, so strip out
- // those endings first as they're one of the last manglings applied to
- // symbol names.
- let llvm = ".llvm.";
- if let Some(i) = s.find(llvm) {
- let candidate = &s[i + llvm.len()..];
- let all_hex = candidate.chars().all(|c| {
- match c {
- 'A' ..= 'F' | '0' ..= '9' => true,
- _ => false,
- }
- });
-
- if all_hex {
- s = &s[..i];
- }
- }
-
- // 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 mut valid = true;
- let mut inner = s;
- if s.len() > 4 && s.starts_with("_ZN") && s.ends_with("E") {
- inner = &s[3 .. s.len() - 1];
- // On Windows, dbghelp strips leading underscores, so we accept "ZN...E" form too.
- } else if s.len() > 3 && s.starts_with("ZN") && s.ends_with("E") {
- inner = &s[2 .. s.len() - 1];
- } else {
- valid = false;
- }
-
- if valid {
- let mut chars = inner.chars();
- while valid {
- let mut i = 0;
- for c in chars.by_ref() {
- if c.is_numeric() {
- i = i * 10 + c as usize - '0' as usize;
- } else {
- break
- }
- }
- if i == 0 {
- valid = chars.next().is_none();
- break
- } else if chars.by_ref().take(i - 1).count() != i - 1 {
- valid = false;
- }
- }
- }
-
- // Alright, let's do this.
- if !valid {
- writer.write_all(s.as_bytes())?;
- } else {
- // remove the `::hfc2edb670e5eda97` part at the end of the symbol.
- if format == PrintFormat::Short {
- // The symbol in still mangled.
- let mut split = inner.rsplitn(2, "17h");
- match (split.next(), split.next()) {
- (Some(addr), rest) => {
- if addr.len() == 16 &&
- addr.chars().all(|c| c.is_digit(16))
- {
- inner = rest.unwrap_or("");
- }
- }
- _ => (),
- }
- }
-
- let mut first = true;
- while !inner.is_empty() {
- if !first {
- writer.write_all(b"::")?;
- } else {
- first = false;
- }
- let mut rest = inner;
- while rest.chars().next().unwrap().is_numeric() {
- rest = &rest[1..];
- }
- let i: usize = inner[.. (inner.len() - rest.len())].parse().unwrap();
- inner = &rest[i..];
- rest = &rest[..i];
- if rest.starts_with("_$") {
- rest = &rest[1..];
- }
- while !rest.is_empty() {
- if rest.starts_with(".") {
- if let Some('.') = rest[1..].chars().next() {
- writer.write_all(b"::")?;
- rest = &rest[2..];
- } else {
- writer.write_all(b".")?;
- rest = &rest[1..];
- }
- } else if rest.starts_with("$") {
- macro_rules! demangle {
- ($($pat:expr => $demangled:expr),*) => ({
- $(if rest.starts_with($pat) {
- writer.write_all($demangled)?;
- rest = &rest[$pat.len()..];
- } else)*
- {
- writer.write_all(rest.as_bytes())?;
- break;
- }
-
- })
- }
-
- // see src/librustc/back/link.rs for these mappings
- demangle! (
- "$SP$" => b"@",
- "$BP$" => b"*",
- "$RF$" => b"&",
- "$LT$" => b"<",
- "$GT$" => b">",
- "$LP$" => b"(",
- "$RP$" => b")",
- "$C$" => b",",
-
- // in theory we can demangle any Unicode code point, but
- // for simplicity we just catch the common ones.
- "$u7e$" => b"~",
- "$u20$" => b" ",
- "$u27$" => b"'",
- "$u5b$" => b"[",
- "$u5d$" => b"]",
- "$u7b$" => b"{",
- "$u7d$" => b"}",
- "$u3b$" => b";",
- "$u2b$" => b"+",
- "$u22$" => b"\""
- )
- } else {
- let idx = match rest.char_indices().find(|&(_, c)| c == '$' || c == '.') {
- None => rest.len(),
- Some((i, _)) => i,
- };
- writer.write_all(rest[..idx].as_bytes())?;
- rest = &rest[idx..];
- }
- }
- }
- }
-
- Ok(())
-}
-
-#[cfg(test)]
-mod tests {
- use sys_common;
- macro_rules! t { ($a:expr, $b:expr) => ({
- let mut m = Vec::new();
- sys_common::backtrace::demangle(&mut m,
- $a,
- super::PrintFormat::Full).unwrap();
- assert_eq!(String::from_utf8(m).unwrap(), $b);
- }) }
-
- #[test]
- fn demangle() {
- t!("test", "test");
- t!("_ZN4testE", "test");
- t!("_ZN4test", "_ZN4test");
- t!("_ZN4test1a2bcE", "test::a::bc");
- }
-
- #[test]
- fn demangle_dollars() {
- t!("_ZN4$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$$GT$E", "Bar<[u32; 4]>");
- }
-
- #[test]
- fn demangle_many_dollars() {
- t!("_ZN13test$u20$test4foobE", "test test::foob");
- t!("_ZN12test$BP$test4foobE", "test*test::foob");
- }
-
- #[test]
- fn demangle_windows() {
- t!("ZN4testE", "test");
- t!("ZN13test$u20$test4foobE", "test test::foob");
- t!("ZN12test$RF$test4foobE", "test&test::foob");
- }
-
- #[test]
- fn demangle_elements_beginning_with_underscore() {
- t!("_ZN13_$LT$test$GT$E", "<test>");
- t!("_ZN28_$u7b$$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");
- }
-}