1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Simple backtrace functionality (to print on failure)
13 #![allow(non_camel_case_types)]
16 use collections::Collection;
17 use from_str::from_str;
18 use io::{IoResult, Writer};
20 use option::{Some, None};
22 use result::{Ok, Err};
26 pub use self::imp::write;
28 // For now logging is turned off by default, and this function checks to see
29 // whether the magical environment variable is present to see if it's turned on.
30 pub fn log_enabled() -> bool {
31 static mut ENABLED: atomics::AtomicInt = atomics::INIT_ATOMIC_INT;
33 match ENABLED.load(atomics::SeqCst) {
40 let val = match os::getenv("RUST_BACKTRACE") {
44 unsafe { ENABLED.store(val, atomics::SeqCst); }
48 #[cfg(target_word_size = "64")] static HEX_WIDTH: uint = 18;
49 #[cfg(target_word_size = "32")] static HEX_WIDTH: uint = 10;
51 // All rust symbols are in theory lists of "::"-separated identifiers. Some
52 // assemblers, however, can't handle these characters in symbol names. To get
53 // around this, we use C++-style mangling. The mangling method is:
55 // 1. Prefix the symbol with "_ZN"
56 // 2. For each element of the path, emit the length plus the element
57 // 3. End the path with "E"
59 // For example, "_ZN4testE" => "test" and "_ZN3foo3bar" => "foo::bar".
61 // We're the ones printing our backtraces, so we can't rely on anything else to
62 // demangle our symbols. It's *much* nicer to look at demangled symbols, so
63 // this function is implemented to give us nice pretty output.
65 // Note that this demangler isn't quite as fancy as it could be. We have lots
66 // of other information in our symbols like hashes, version, type information,
67 // etc. Additionally, this doesn't handle glue symbols at all.
68 fn demangle(writer: &mut Writer, s: &str) -> IoResult<()> {
69 // First validate the symbol. If it doesn't look like anything we're
70 // expecting, we just print it literally. Note that we must handle non-rust
71 // symbols because we could have any function in the backtrace.
73 if s.len() > 4 && s.starts_with("_ZN") && s.ends_with("E") {
74 let mut chars = s.slice(3, s.len() - 1).chars();
79 i = i * 10 + c as uint - '0' as uint;
85 valid = chars.next().is_none();
87 } else if chars.by_ref().take(i - 1).count() != i - 1 {
95 // Alright, let's do this.
97 try!(writer.write_str(s));
99 let mut s = s.slice_from(3);
100 let mut first = true;
103 try!(writer.write_str("::"));
108 while rest.char_at(0).is_digit() {
109 rest = rest.slice_from(1);
111 let i: uint = from_str(s.slice_to(s.len() - rest.len())).unwrap();
112 s = rest.slice_from(i);
113 rest = rest.slice_to(i);
114 while rest.len() > 0 {
115 if rest.starts_with("$") {
116 macro_rules! demangle(
117 ($($pat:expr => $demangled:expr),*) => ({
118 $(if rest.starts_with($pat) {
119 try!(writer.write_str($demangled));
120 rest = rest.slice_from($pat.len());
123 try!(writer.write_str(rest));
129 // see src/librustc/back/link.rs for these mappings
141 // in theory we can demangle any unicode code point, but
142 // for simplicity we just catch the common ones.
149 let idx = match rest.find('$') {
153 try!(writer.write_str(rest.slice_to(idx)));
154 rest = rest.slice_from(idx);
163 /// Backtrace support built on libgcc with some extra OS-specific support
165 /// Some methods of getting a backtrace:
167 /// * The backtrace() functions on unix. It turns out this doesn't work very
168 /// well for green threads on OSX, and the address to symbol portion of it
169 /// suffers problems that are described below.
171 /// * Using libunwind. This is more difficult than it sounds because libunwind
172 /// isn't installed everywhere by default. It's also a bit of a hefty library,
173 /// so possibly not the best option. When testing, libunwind was excellent at
174 /// getting both accurate backtraces and accurate symbols across platforms.
175 /// This route was not chosen in favor of the next option, however.
177 /// * We're already using libgcc_s for exceptions in rust (triggering task
178 /// unwinding and running destructors on the stack), and it turns out that it
179 /// conveniently comes with a function that also gives us a backtrace. All of
180 /// these functions look like _Unwind_*, but it's not quite the full
181 /// repertoire of the libunwind API. Due to it already being in use, this was
182 /// the chosen route of getting a backtrace.
184 /// After choosing libgcc_s for backtraces, the sad part is that it will only
185 /// give us a stack trace of instruction pointers. Thankfully these instruction
186 /// pointers are accurate (they work for green and native threads), but it's
187 /// then up to us again to figure out how to translate these addresses to
188 /// symbols. As with before, we have a few options. Before, that, a little bit
189 /// of an interlude about symbols. This is my very limited knowledge about
190 /// symbol tables, and this information is likely slightly wrong, but the
191 /// general idea should be correct.
193 /// When talking about symbols, it's helpful to know a few things about where
194 /// symbols are located. Some symbols are located in the dynamic symbol table
195 /// of the executable which in theory means that they're available for dynamic
196 /// linking and lookup. Other symbols end up only in the local symbol table of
197 /// the file. This loosely corresponds to pub and priv functions in Rust.
199 /// Armed with this knowledge, we know that our solution for address to symbol
200 /// translation will need to consult both the local and dynamic symbol tables.
201 /// With that in mind, here's our options of translating an address to
204 /// * Use dladdr(). The original backtrace()-based idea actually uses dladdr()
205 /// behind the scenes to translate, and this is why backtrace() was not used.
206 /// Conveniently, this method works fantastically on OSX. It appears dladdr()
207 /// uses magic to consult the local symbol table, or we're putting everything
208 /// in the dynamic symbol table anyway. Regardless, for OSX, this is the
209 /// method used for translation. It's provided by the system and easy to do.o
211 /// Sadly, all other systems have a dladdr() implementation that does not
212 /// consult the local symbol table. This means that most functions are blank
213 /// because they don't have symbols. This means that we need another solution.
215 /// * Use unw_get_proc_name(). This is part of the libunwind api (not the
216 /// libgcc_s version of the libunwind api), but involves taking a dependency
217 /// to libunwind. We may pursue this route in the future if we bundle
218 /// libunwind, but libunwind was unwieldy enough that it was not chosen at
219 /// this time to provide this functionality.
221 /// * Shell out to a utility like `readelf`. Crazy though it may sound, it's a
222 /// semi-reasonable solution. The stdlib already knows how to spawn processes,
223 /// so in theory it could invoke readelf, parse the output, and consult the
224 /// local/dynamic symbol tables from there. This ended up not getting chosen
225 /// due to the craziness of the idea plus the advent of the next option.
227 /// * Use `libbacktrace`. It turns out that this is a small library bundled in
228 /// the gcc repository which provides backtrace and symbol translation
229 /// functionality. All we really need from it is the backtrace functionality,
230 /// and we only really need this on everything that's not OSX, so this is the
231 /// chosen route for now.
233 /// In summary, the current situation uses libgcc_s to get a trace of stack
234 /// pointers, and we use dladdr() or libbacktrace to translate these addresses
235 /// to symbols. This is a bit of a hokey implementation as-is, but it works for
236 /// all unix platforms we support right now, so it at least gets the job done.
240 use io::{IoResult, IoError, Writer};
243 use option::{Some, None, Option};
244 use result::{Ok, Err};
245 use rt::mutex::{StaticNativeMutex, NATIVE_MUTEX_INIT};
249 writer: &'a mut Writer,
250 last_error: Option<IoError>,
253 #[inline(never)] // if we know this is a function call, we can skip it when
255 pub fn write(w: &mut Writer) -> IoResult<()> {
256 // When using libbacktrace, we use some necessary global state, so we
257 // need to prevent more than one thread from entering this block. This
258 // is semi-reasonable in terms of printing anyway, and we know that all
259 // I/O done here is blocking I/O, not green I/O, so we don't have to
260 // worry about this being a native vs green mutex.
261 static mut LOCK: StaticNativeMutex = NATIVE_MUTEX_INIT;
262 let _g = unsafe { LOCK.lock() };
264 try!(writeln!(w, "stack backtrace:"));
266 let mut cx = Context { writer: w, last_error: None, idx: 0 };
267 return match unsafe {
268 uw::_Unwind_Backtrace(trace_fn,
269 &mut cx as *mut Context as *libc::c_void)
271 uw::_URC_NO_REASON => {
272 match cx.last_error {
273 Some(err) => Err(err),
280 extern fn trace_fn(ctx: *uw::_Unwind_Context,
281 arg: *libc::c_void) -> uw::_Unwind_Reason_Code {
282 let cx: &mut Context = unsafe { mem::transmute(arg) };
283 let ip = unsafe { uw::_Unwind_GetIP(ctx) as *libc::c_void };
284 // dladdr() on osx gets whiny when we use FindEnclosingFunction, and
285 // it appears to work fine without it, so we only use
286 // FindEnclosingFunction on non-osx platforms. In doing so, we get a
287 // slightly more accurate stack trace in the process.
289 // This is often because failure involves the last instruction of a
290 // function being "call std::rt::begin_unwind", with no ret
291 // instructions after it. This means that the return instruction
292 // pointer points *outside* of the calling function, and by
293 // unwinding it we go back to the original function.
294 let ip = if cfg!(target_os = "macos") {
297 unsafe { uw::_Unwind_FindEnclosingFunction(ip) }
300 // Don't print out the first few frames (they're not user frames)
302 if cx.idx <= 0 { return uw::_URC_NO_REASON }
303 // Don't print ginormous backtraces
305 match write!(cx.writer, " ... <frames omitted>\n") {
307 Err(e) => { cx.last_error = Some(e); }
309 return uw::_URC_FAILURE
312 // Once we hit an error, stop trying to print more frames
313 if cx.last_error.is_some() { return uw::_URC_FAILURE }
315 match print(cx.writer, cx.idx, ip) {
317 Err(e) => { cx.last_error = Some(e); }
321 return uw::_URC_NO_REASON
325 #[cfg(target_os = "macos")]
326 fn print(w: &mut Writer, idx: int, addr: *libc::c_void) -> IoResult<()> {
330 dli_fname: *libc::c_char,
331 dli_fbase: *libc::c_void,
332 dli_sname: *libc::c_char,
333 dli_saddr: *libc::c_void,
336 fn dladdr(addr: *libc::c_void,
337 info: *mut Dl_info) -> libc::c_int;
340 let mut info: Dl_info = unsafe { intrinsics::init() };
341 if unsafe { dladdr(addr, &mut info) == 0 } {
342 output(w, idx,addr, None)
344 output(w, idx, addr, Some(unsafe {
345 CString::new(info.dli_sname, false)
350 #[cfg(not(target_os = "macos"))]
351 fn print(w: &mut Writer, idx: int, addr: *libc::c_void) -> IoResult<()> {
352 use collections::Collection;
355 use path::GenericPath;
358 use slice::{ImmutableVector, MutableVector};
360 ////////////////////////////////////////////////////////////////////////
361 // libbacktrace.h API
362 ////////////////////////////////////////////////////////////////////////
363 type backtrace_syminfo_callback =
364 extern "C" fn(data: *mut libc::c_void,
366 symname: *libc::c_char,
367 symval: libc::uintptr_t,
368 symsize: libc::uintptr_t);
369 type backtrace_error_callback =
370 extern "C" fn(data: *mut libc::c_void,
372 errnum: libc::c_int);
373 enum backtrace_state {}
374 #[link(name = "backtrace", kind = "static")]
376 fn backtrace_create_state(filename: *libc::c_char,
377 threaded: libc::c_int,
378 error: backtrace_error_callback,
379 data: *mut libc::c_void)
380 -> *mut backtrace_state;
381 fn backtrace_syminfo(state: *mut backtrace_state,
382 addr: libc::uintptr_t,
383 cb: backtrace_syminfo_callback,
384 error: backtrace_error_callback,
385 data: *mut libc::c_void) -> libc::c_int;
388 ////////////////////////////////////////////////////////////////////////
390 ////////////////////////////////////////////////////////////////////////
392 extern fn error_cb(_data: *mut libc::c_void, _msg: *libc::c_char,
393 _errnum: libc::c_int) {
394 // do nothing for now
396 extern fn syminfo_cb(data: *mut libc::c_void,
397 _pc: libc::uintptr_t,
398 symname: *libc::c_char,
399 _symval: libc::uintptr_t,
400 _symsize: libc::uintptr_t) {
401 let slot = data as *mut *libc::c_char;
402 unsafe { *slot = symname; }
405 // The libbacktrace API supports creating a state, but it does not
406 // support destroying a state. I personally take this to mean that a
407 // state is meant to be created and then live forever.
409 // I would love to register an at_exit() handler which cleans up this
410 // state, but libbacktrace provides no way to do so.
412 // With these constraints, this function has a statically cached state
413 // that is calculated the first time this is requested. Remember that
414 // backtracing all happens serially (one global lock).
416 // An additionally oddity in this function is that we initialize the
417 // filename via self_exe_name() to pass to libbacktrace. It turns out
418 // that on linux libbacktrace seamlessly gets the filename of the
419 // current executable, but this fails on freebsd. by always providing
420 // it, we make sure that libbacktrace never has a reason to not look up
421 // the symbols. The libbacktrace API also states that the filename must
422 // be in "permanent memory", so we copy it to a static and then use the
423 // static as the pointer.
424 unsafe fn init_state() -> *mut backtrace_state {
425 static mut STATE: *mut backtrace_state = 0 as *mut backtrace_state;
426 static mut LAST_FILENAME: [libc::c_char, ..256] = [0, ..256];
427 if !STATE.is_null() { return STATE }
428 let selfname = if cfg!(target_os = "freebsd") {
433 let filename = match selfname {
435 let bytes = path.as_vec();
436 if bytes.len() < LAST_FILENAME.len() {
437 let i = bytes.iter();
438 for (slot, val) in LAST_FILENAME.mut_iter().zip(i) {
439 *slot = *val as libc::c_char;
441 LAST_FILENAME.as_ptr()
448 STATE = backtrace_create_state(filename, 0, error_cb,
453 ////////////////////////////////////////////////////////////////////////
455 ////////////////////////////////////////////////////////////////////////
457 // backtrace errors are currently swept under the rug, only I/O
458 // errors are reported
459 let state = unsafe { init_state() };
461 return output(w, idx, addr, None)
463 let mut data = 0 as *libc::c_char;
464 let data_addr = &mut data as *mut *libc::c_char;
466 backtrace_syminfo(state, addr as libc::uintptr_t,
467 syminfo_cb, error_cb,
468 data_addr as *mut libc::c_void)
470 if ret == 0 || data.is_null() {
471 output(w, idx, addr, None)
473 output(w, idx, addr, Some(unsafe { CString::new(data, false) }))
477 // Finally, after all that work above, we can emit a symbol.
478 fn output(w: &mut Writer, idx: int, addr: *libc::c_void,
479 s: Option<CString>) -> IoResult<()> {
480 try!(write!(w, " {:2}: {:2$} - ", idx, addr, super::HEX_WIDTH));
481 match s.as_ref().and_then(|c| c.as_str()) {
482 Some(string) => try!(super::demangle(w, string)),
483 None => try!(write!(w, "<unknown>")),
485 w.write(['\n' as u8])
488 /// Unwind library interface used for backtraces
490 /// Note that the native libraries come from librustrt, not this module.
491 #[allow(non_camel_case_types)]
492 #[allow(non_snake_case_functions)]
497 pub enum _Unwind_Reason_Code {
499 _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
500 _URC_FATAL_PHASE2_ERROR = 2,
501 _URC_FATAL_PHASE1_ERROR = 3,
502 _URC_NORMAL_STOP = 4,
503 _URC_END_OF_STACK = 5,
504 _URC_HANDLER_FOUND = 6,
505 _URC_INSTALL_CONTEXT = 7,
506 _URC_CONTINUE_UNWIND = 8,
507 _URC_FAILURE = 9, // used only by ARM EABI
510 pub enum _Unwind_Context {}
512 pub type _Unwind_Trace_Fn =
513 extern fn(ctx: *_Unwind_Context,
514 arg: *libc::c_void) -> _Unwind_Reason_Code;
517 pub fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn,
518 trace_argument: *libc::c_void)
519 -> _Unwind_Reason_Code;
521 #[cfg(not(target_os = "android"),
522 not(target_os = "linux", target_arch = "arm"))]
523 pub fn _Unwind_GetIP(ctx: *_Unwind_Context) -> libc::uintptr_t;
524 #[cfg(not(target_os = "android"),
525 not(target_os = "linux", target_arch = "arm"))]
526 pub fn _Unwind_FindEnclosingFunction(pc: *libc::c_void)
530 // On android, the function _Unwind_GetIP is a macro, and this is the
531 // expansion of the macro. This is all copy/pasted directly from the
532 // header file with the definition of _Unwind_GetIP.
533 #[cfg(target_os = "android")]
534 #[cfg(target_os = "linux", target_arch = "arm")]
535 pub unsafe fn _Unwind_GetIP(ctx: *_Unwind_Context) -> libc::uintptr_t {
537 enum _Unwind_VRS_Result {
539 _UVRSR_NOT_IMPLEMENTED = 1,
543 enum _Unwind_VRS_RegClass {
551 enum _Unwind_VRS_DataRepresentation {
560 type _Unwind_Word = libc::c_uint;
562 fn _Unwind_VRS_Get(ctx: *_Unwind_Context,
563 klass: _Unwind_VRS_RegClass,
565 repr: _Unwind_VRS_DataRepresentation,
566 data: *mut libc::c_void)
567 -> _Unwind_VRS_Result;
570 let mut val: _Unwind_Word = 0;
571 let ptr = &mut val as *mut _Unwind_Word;
572 let _ = _Unwind_VRS_Get(ctx, _UVRSC_CORE, 15, _UVRSD_UINT32,
573 ptr as *mut libc::c_void);
574 (val & !1) as libc::uintptr_t
577 // This function also doesn't exist on android or arm/linux, so make it
579 #[cfg(target_os = "android")]
580 #[cfg(target_os = "linux", target_arch = "arm")]
581 pub unsafe fn _Unwind_FindEnclosingFunction(pc: *libc::c_void)
589 /// As always, windows has something very different than unix, we mainly want
590 /// to avoid having to depend too much on libunwind for windows.
592 /// If you google around, you'll find a fair bit of references to built-in
593 /// functions to get backtraces on windows. It turns out that most of these are
594 /// in an external library called dbghelp. I was unable to find this library
595 /// via `-ldbghelp`, but it is apparently normal to do the `dlopen` equivalent
598 /// You'll also find that there's a function called CaptureStackBackTrace
599 /// mentioned frequently (which is also easy to use), but sadly I didn't have a
600 /// copy of that function in my mingw install (maybe it was broken?). Instead,
601 /// this takes the route of using StackWalk64 in order to walk the stack.
603 #[allow(dead_code, uppercase_variables)]
606 use core_collections::Collection;
608 use io::{IoResult, Writer};
612 use option::{Some, None};
614 use result::{Ok, Err};
615 use rt::mutex::{StaticNativeMutex, NATIVE_MUTEX_INIT};
616 use slice::ImmutableVector;
618 use dynamic_lib::DynamicLibrary;
620 #[allow(non_snake_case_functions)]
622 fn GetCurrentProcess() -> libc::HANDLE;
623 fn GetCurrentThread() -> libc::HANDLE;
624 fn RtlCaptureContext(ctx: *mut arch::CONTEXT);
628 extern "system" fn(libc::HANDLE, u64, *mut u64,
629 *mut SYMBOL_INFO) -> libc::BOOL;
630 type SymInitializeFn =
631 extern "system" fn(libc::HANDLE, *libc::c_void,
632 libc::BOOL) -> libc::BOOL;
634 extern "system" fn(libc::HANDLE) -> libc::BOOL;
637 extern "system" fn(libc::DWORD, libc::HANDLE, libc::HANDLE,
638 *mut STACKFRAME64, *mut arch::CONTEXT,
639 *libc::c_void, *libc::c_void,
640 *libc::c_void, *libc::c_void) -> libc::BOOL;
642 static MAX_SYM_NAME: uint = 2000;
643 static IMAGE_FILE_MACHINE_I386: libc::DWORD = 0x014c;
644 static IMAGE_FILE_MACHINE_IA64: libc::DWORD = 0x0200;
645 static IMAGE_FILE_MACHINE_AMD64: libc::DWORD = 0x8664;
649 SizeOfStruct: libc::c_ulong,
650 TypeIndex: libc::c_ulong,
651 Reserved: [u64, ..2],
652 Index: libc::c_ulong,
655 Flags: libc::c_ulong,
658 Register: libc::c_ulong,
659 Scope: libc::c_ulong,
661 NameLen: libc::c_ulong,
662 MaxNameLen: libc::c_ulong,
663 // note that windows has this as 1, but it basically just means that
664 // the name is inline at the end of the struct. For us, we just bump
665 // the struct size up to MAX_SYM_NAME.
666 Name: [libc::c_char, ..MAX_SYM_NAME],
683 struct STACKFRAME64 {
685 AddrReturn: ADDRESS64,
686 AddrFrame: ADDRESS64,
687 AddrStack: ADDRESS64,
688 AddrBStore: ADDRESS64,
689 FuncTableEntry: *libc::c_void,
693 Reserved: [u64, ..3],
699 ThCallbackStack: libc::DWORD,
700 ThCallbackBStore: libc::DWORD,
701 NextCallback: libc::DWORD,
702 FramePointer: libc::DWORD,
704 KeUserCallbackDispatcher: u64,
705 SystemRangeStart: u64,
706 KiUserExceptionDispatcher: u64,
709 Reserved: [u64, ..5],
712 #[cfg(target_arch = "x86")]
716 static MAXIMUM_SUPPORTED_EXTENSION: uint = 512;
719 ContextFlags: libc::DWORD,
726 FloatSave: FLOATING_SAVE_AREA,
743 ExtendedRegisters: [u8, ..MAXIMUM_SUPPORTED_EXTENSION],
746 pub struct FLOATING_SAVE_AREA {
747 ControlWord: libc::DWORD,
748 StatusWord: libc::DWORD,
749 TagWord: libc::DWORD,
750 ErrorOffset: libc::DWORD,
751 ErrorSelector: libc::DWORD,
752 DataOffset: libc::DWORD,
753 DataSelector: libc::DWORD,
754 RegisterArea: [u8, ..80],
755 Cr0NpxState: libc::DWORD,
758 pub fn init_frame(frame: &mut super::STACKFRAME64,
759 ctx: &CONTEXT) -> libc::DWORD {
760 frame.AddrPC.Offset = ctx.Eip as u64;
761 frame.AddrPC.Mode = super::AddrModeFlat;
762 frame.AddrStack.Offset = ctx.Esp as u64;
763 frame.AddrStack.Mode = super::AddrModeFlat;
764 frame.AddrFrame.Offset = ctx.Ebp as u64;
765 frame.AddrFrame.Mode = super::AddrModeFlat;
766 super::IMAGE_FILE_MACHINE_I386
770 #[cfg(target_arch = "x86_64")]
772 use libc::{c_longlong, c_ulonglong};
773 use libc::types::os::arch::extra::{WORD, DWORD, DWORDLONG};
820 FltSave: FLOATING_SAVE_AREA,
822 VectorRegister: [M128A, .. 26],
823 VectorControl: DWORDLONG,
825 DebugControl: DWORDLONG,
826 LastBranchToRip: DWORDLONG,
827 LastBranchFromRip: DWORDLONG,
828 LastExceptionToRip: DWORDLONG,
829 LastExceptionFromRip: DWORDLONG,
837 pub struct FLOATING_SAVE_AREA {
838 _Dummy: [u8, ..512] // FIXME: Fill this out
841 pub fn init_frame(frame: &mut super::STACKFRAME64,
842 ctx: &CONTEXT) -> DWORD {
843 frame.AddrPC.Offset = ctx.Rip as u64;
844 frame.AddrPC.Mode = super::AddrModeFlat;
845 frame.AddrStack.Offset = ctx.Rsp as u64;
846 frame.AddrStack.Mode = super::AddrModeFlat;
847 frame.AddrFrame.Offset = ctx.Rbp as u64;
848 frame.AddrFrame.Mode = super::AddrModeFlat;
849 super::IMAGE_FILE_MACHINE_AMD64
854 handle: libc::HANDLE,
855 SymCleanup: SymCleanupFn,
858 impl Drop for Cleanup {
859 fn drop(&mut self) { (self.SymCleanup)(self.handle); }
862 pub fn write(w: &mut Writer) -> IoResult<()> {
863 // According to windows documentation, all dbghelp functions are
865 static mut LOCK: StaticNativeMutex = NATIVE_MUTEX_INIT;
866 let _g = unsafe { LOCK.lock() };
868 // Open up dbghelp.dll, we don't link to it explicitly because it can't
869 // always be found. Additionally, it's nice having fewer dependencies.
870 let path = Path::new("dbghelp.dll");
871 let lib = match DynamicLibrary::open(Some(&path)) {
873 Err(..) => return Ok(()),
876 macro_rules! sym( ($e:expr, $t:ident) => (
877 match unsafe { lib.symbol::<$t>($e) } {
879 Err(..) => return Ok(())
883 // Fetch the symbols necessary from dbghelp.dll
884 let SymFromAddr = sym!("SymFromAddr", SymFromAddrFn);
885 let SymInitialize = sym!("SymInitialize", SymInitializeFn);
886 let SymCleanup = sym!("SymCleanup", SymCleanupFn);
887 let StackWalk64 = sym!("StackWalk64", StackWalk64Fn);
889 // Allocate necessary structures for doing the stack walk
890 let process = unsafe { GetCurrentProcess() };
891 let thread = unsafe { GetCurrentThread() };
892 let mut context: arch::CONTEXT = unsafe { intrinsics::init() };
893 unsafe { RtlCaptureContext(&mut context); }
894 let mut frame: STACKFRAME64 = unsafe { intrinsics::init() };
895 let image = arch::init_frame(&mut frame, &context);
897 // Initialize this process's symbols
898 let ret = SymInitialize(process, 0 as *libc::c_void, libc::TRUE);
899 if ret != libc::TRUE { return Ok(()) }
900 let _c = Cleanup { handle: process, SymCleanup: SymCleanup };
902 // And now that we're done with all the setup, do the stack walking!
904 try!(write!(w, "stack backtrace:\n"));
905 while StackWalk64(image, process, thread, &mut frame, &mut context,
906 0 as *libc::c_void, 0 as *libc::c_void,
907 0 as *libc::c_void, 0 as *libc::c_void) == libc::TRUE{
908 let addr = frame.AddrPC.Offset;
909 if addr == frame.AddrReturn.Offset || addr == 0 ||
910 frame.AddrReturn.Offset == 0 { break }
913 try!(write!(w, " {:2}: {:#2$x}", i, addr, super::HEX_WIDTH));
914 let mut info: SYMBOL_INFO = unsafe { intrinsics::init() };
915 info.MaxNameLen = MAX_SYM_NAME as libc::c_ulong;
916 info.SizeOfStruct = (mem::size_of::<SYMBOL_INFO>() -
917 info.Name.len() + 1) as libc::c_ulong;
919 let mut displacement = 0u64;
920 let ret = SymFromAddr(process, addr as u64, &mut displacement,
923 if ret == libc::TRUE {
924 try!(write!(w, " - "));
925 let cstr = unsafe { CString::new(info.Name.as_ptr(), false) };
926 let bytes = cstr.as_bytes();
927 match cstr.as_str() {
928 Some(s) => try!(super::demangle(w, s)),
929 None => try!(w.write(bytes.slice_to(bytes.len() - 1))),
932 try!(w.write(['\n' as u8]));
945 macro_rules! t( ($a:expr, $b:expr) => ({
946 let mut m = MemWriter::new();
947 super::demangle(&mut m, $a).unwrap();
948 assert_eq!(str::from_utf8(m.unwrap().as_slice()).unwrap().to_owned(), $b.to_owned());
954 t!("_ZN4testE", "test");
955 t!("_ZN4test", "_ZN4test");
956 t!("_ZN4test1a2bcE", "test::a::bc");
960 fn demangle_dollars() {
961 t!("_ZN4$UP$E", "Box");
962 t!("_ZN8$UP$testE", "Boxtest");
963 t!("_ZN8$UP$test4foobE", "Boxtest::foob");
964 t!("_ZN8$x20test4foobE", " test::foob");
968 fn demangle_many_dollars() {
969 t!("_ZN12test$x20test4foobE", "test test::foob");
970 t!("_ZN12test$UP$test4foobE", "testBoxtest::foob");