[Bug sanitizer/80578] -fsanitize=undefined report yields memory leak

["marxin at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80578

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P5
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-05-02
     Ever confirmed|0                           |1

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed, it's caused by fact that the vptr ubsan error calls demangler to
display type name. That's the place where the memory is allocated and not
properly released.

If you take a look at
libsanitizer/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc, there's
comment that confirms it's a known issue:

const char *DemangleCXXABI(const char *name) {
  // FIXME: __cxa_demangle aggressively insists on allocating memory.
  // There's not much we can do about that, short of providing our
  // own demangler (libc++abi's implementation could be adapted so that
  // it does not allocate). For now, we just call it anyway, and we leak
  // the returned value.
  if (__cxxabiv1::__cxa_demangle)
    if (const char *demangled_name =
          __cxxabiv1::__cxa_demangle(name, 0, 0, 0))
      return demangled_name;

  return name;
}

I'm assigning that low priority.