Summary:
This patch is similar to the <list> fix but it has a few differences. This patch doesn't use a `__link_pointer` typedef because we don't need to change the linked list pointers because `forward_list` never stores a `__forward_begin_node` in the linked list itself.
The issue with `forward_list` is that the iterators store pointers to `__forward_list_node` and not `__forward_begin_node`. This is incorrect because `before_begin()` and `cbefore_begin()` return iterators that point to a `__forward_begin_node`. This means we incorrectly downcast the `__forward_begin_node` pointer to a `__node_pointer`. This downcast itself is sometimes UB but it cannot be safely removed until ABI v2. The more common cause of UB is when we deference the downcast pointer. (for example `__ptr_->__next_`). This can be fixed without an ABI break by upcasting `__ptr_` before accessing it.
The fix is as follows:
1. Introduce a `__iter_node_pointer` typedef that works similar to `__link_pointer` in the last patch. In ABI v2 it is always a typedef for `__begin_node_pointer`.
2. Change the `__before_begin()` method to return the correct pointer type (`__begin_node_pointer`),
Previously it incorrectly downcasted the `__forward_begin_node` to a `__node_pointer` so it could be used to constructor the iterator types.
3. Change `__forward_list_iterator` and `__forward_list_const_iterator` in the following way:
1. Change `__node_pointer __ptr_;` member to have the `__iter_node_pointer` type instead.
2. Add additional private constructors that accept `__begin_node_pointer` in addition to `__node_pointer` and then correctly cast them to the stored `__iter_node_pointer` type.
3. Add `__get_begin()` and `__get_node_unchecked()` accessor methods that correctly cast `__ptr_` to the expected pointer type. `__get_begin()` is always safe to use and should be
preferred. `__get_node_unchecked()` can only be used on a deferencible iterator.
4. Replace direct access to `__forward_list_iterator::__ptr_` with the safe accessor methods.
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D15836
llvm-svn: 258888
This patch makes it easier to support running the lit tests for new and
unusual platforms. It will break existing users that set
LIBCXX_TARGET_INFO to anything other than the default. I think this is
fine, because the old LIBCXX_TARGET_INFO wasn't terribly useful.
The old way of supporting the different test platforms was to have
conditional code scattered throughout config.py. New platforms would need
to add conditionals there. Alternatively, the new platform could set
no_default_flags to true, and reconstitue almost the entire compile and
link line, including things that don't vary across platforms.
The new way of supporting new platforms is to create a new target info
class, and have make_target_info return an instance of it. For platforms
supported in-tree, that will be done by modifying make_target_info. For
out-of-tree platforms, users can set LIBCXX_TARGET_INFO at cmake configure
time.
The target info sub-classes can provide fine-grained information back to
config.py. The hooks that will most commonly be provided will be
add_cxx_compile_flags and add_cxx_link_flags. These hooks can provide the
platform specific flags, while letting config.py handle all the invariant
flags.
Target info hooks were added for each area that the existing config.py had
platform specific behavior. config.py is now mostly free of platform
specific conditionals.
This patch was tested on Linux x86_64. I both targeted Linux x86_64, and
an out-of-tree platform with a custom target_info. In both cases I was
able to run libcxx and libcxxabi tests. I do not have access to FreeBSD,
Darwin, or Windows machines that are set up for lit testing.
llvm-svn: 256588
This patch goes through and enables C++11 and C++14 features for newer GCC's.
The main changes are:
1. Turn on variable templates. (Uses __cpp_variable_templates)
2. Assert atomic<Tp> is trivially copyable (Uses _GNUC_VER >= 501).
3. Turn on trailing return support for GCC. (Uses _GNUC_VER >= 404)
4. XFAIL void_t test for GCC 5.1 and 5.2. Fixed in GCC 6.
llvm-svn: 255585
Eric Fiselier