This commit changes the libc++ frame recognizer to hide implementation
details of libc++ more aggressively. The applied heuristic is rather
straightforward: We consider every function name starting with `__` as
an implementation detail.
This works pretty neatly for `std::invoke`, `std::function`,
`std::sort`, `std::map::emplace` and many others. Also, this should
align quite nicely with libc++'s general coding convention of using the
`__` for their implementation details, thereby keeping the future
maintenance effort low.
However, this heuristic by itself does not work in 100% of the cases:
E.g., `std::ranges::sort` is not a function, but an object with an
overloaded `operator()`, which means that there is no actual call
`std::ranges::sort` in the call stack. Instead, there is a
`std::ranges::__sort::operator()` call. To make sure that we don't hide
this stack frame, we never hide the frame which represents the entry
point from user code into libc++ code
Works towards P0619R4 / #99985.
The use of `std::get_temporary_buffer` and `std::return_temporary_buffer`
are replaced with `unique_ptr`-based RAII buffer holder.
Escape hatches:
- `_LIBCPP_ENABLE_CXX20_REMOVED_TEMPORARY_BUFFER` restores
`std::get_temporary_buffer` and `std::return_temporary_buffer`.
Drive-by changes:
- In `<syncstream>`, states that `get_temporary_buffer` is now removed,
because `<syncstream>` is added in C++20.
We waited before supporting std::jthread fully because we wanted to
investigate other implementation strategies (in particular one involving
std::mutex). Since then, we did some benchmarking and decided that we
wouldn't be moving forward with std::mutex. Hence, there is no real
reason to punt on making std::jthread & friends non-experimental.
Works towards P0619R4/#99985.
- std::uncaught_exception was not previously deprecated. This patch
deprecates it since C++17 as per N4259. std::uncaught_exceptions is
used instead as libc++ unconditionally provides this function.
- _LIBCPP_ENABLE_CXX20_REMOVED_UNCAUGHT_EXCEPTION restores
std::uncaught_exception.
- As a drive-by, this patch updates the C++20 status page to
explain that D.11 is already done, since it was done in
578d09c1b195d859ca7e62840ff6bb83421a77b5.
- Landing page: add link to the libc++ Discord channel
- Landing page: reorder "Getting Involved" above "Design documents"
- Landing page: remove "Notes and Known Issues" which was completely outdated
- Rename "Using Libc++" to "User Documentation" and update contents
- Rename "Building Libc++" to "Vendor Documentation" and update contents
The "BuildingLibcxx" and "UsingLibcxx" pages have basically been used for
vendor and user documentation respectively. However, they were named in
a way that doesn't really make that clear. Renaming the pages now gives
us a location to clearly document what we target at vendors and what we
target at users, and to do that separately.
