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// Copyright 2014 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.
use prelude::v1::*;
use io::prelude::*;
use io;
#[cfg(target_pointer_width = "64")]
pub const HEX_WIDTH: usize = 18;
#[cfg(target_pointer_width = "32")]
pub const HEX_WIDTH: usize = 10;
// 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 "_ZN3foo3bar" => "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 Write, s: &str) -> io::Result<()> {
// 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 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 {
try!(writer.write_all(s.as_bytes()));
} else {
let mut first = true;
while inner.len() > 0 {
if !first {
try!(writer.write_all(b"::"));
} else {
first = false;
}
let mut rest = inner;
while rest.char_at(0).is_numeric() {
rest = &rest[1..];
}
let i: usize = inner[.. (inner.len() - rest.len())].parse().unwrap();
inner = &rest[i..];
rest = &rest[..i];
while rest.len() > 0 {
if rest.starts_with("$") {
macro_rules! demangle {
($($pat:expr, => $demangled:expr),*) => ({
$(if rest.starts_with($pat) {
try!(writer.write_all($demangled));
rest = &rest[$pat.len()..];
} else)*
{
try!(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"]"
)
} else {
let idx = match rest.find('$') {
None => rest.len(),
Some(i) => i,
};
try!(writer.write_all(rest[..idx].as_bytes()));
rest = &rest[idx..];
}
}
}
}
Ok(())
}
|
