This function converts a single wide character into its multibyte
representation (UTF-8 in our case). It is called from libc++'s
`std::basic_ostream<wchar_t>::flush`, which gets called at program exit
from a global destructor in order to flush `std::wcout`.
Consider the situation where two shared libraries libA and libB, both
depending (as in having a NEEDED dtag) on libC. libA is first
dlopen()-ed, which produces libC to be mapped and linked. When libB is
dlopen()-ed the DynamicLinker would re-map and re-link libC though,
causing any previous references to its old location to be invalid. And
if libA's PLT has been patched to point to libC's symbols, then any
further invocations to libA will cause the code to jump to a virtual
address that isn't mapped anymore, therefore causing a crash. This
situation was reported in #10014, although the setup was more convolved
in the ticket.
This commit fixes the issue by distinguishing between a main program
loading being performed by Loader.so, and a dlopen() call. The main
difference between these two cases is that in the former the
s_globals_objects maps is always empty, while in the latter it might
already contain dependencies for the library being dlopen()-ed. Hence,
when collecting dependencies to map and link, dlopen() should skip those
that are present in the global map to avoid the issue described above.
With this patch the original issue seen in #10014 is gone, with all
python3 modules (so far) loading correctly.
A unit test reproducing a simplified issue is also included in this
commit. The unit test includes the building of two dynamic libraries A
and B with both depending on libline.so (and B also depending on A); the
test then dlopen()s libA, invokes one its function, then does the same
with libB.
Generate a sorted, compressed series of ranges in a match table for
character classes, and use a binary search to find the matches.
This is about a 3-4x speedup for character class match performance. :^)
The callback should be called as soon as the connection is established,
and if we actually set the callback when it already is, we expect it to
be called immediately.
See #10042 for details. In short: qemu doesn't seem to implement that
feature, therefore the test correctly fails. However, that does not help
us, so we skip that test.
This makes it so we don't need to specify the full path to all the
helper scripts we include() from different places in the codebase and
feels a lot cleaner.
