This moves the definition of the internal helpers
`__Unwind_SjLj_GetTopOfFunctionStack` and
`__Unwind_SjLj_SetTopOfFunctionStack` into `Unwind-sjlj.c`. These are
not extra functions specific to Apple, but rather are internal
implementation details of SjLj support in the LLVM libunwind
implementation.
This allows us to remove the internal header unwind_ext.h, as these
functions are not meant to be used as SPI either. Because they are
static, they will be given implicit hidden visibility, but due to the
simplicity should get fully inlined into the actual use.
Use the C11 standard static TLS annotation (`_Thread_local`) if
possible, otherwise, use the Windows specific `__declspec(thread)` when
targeting Windows or the GNU `__thread` extension. In theory, it should
be possible for this implementation to use a `pthread_setspecific` and
`pthread_getspecific` on platforms with pthreads or `SetFlsValue` and
`GetFlsValue` on Windows for non-static TLS. However, static TLS tends
to be significantly faster, so we really should prefer that over the
dynamic TLS approach. On Apple environments, when not building for the
loader (dyld), use the pre-allocated TLS slot in the loader rather than
the local static TLS variable.
Note that the un-threaded support of libunwind is still present as
before, however, it is unsafe to use in a threaded environment as the
cleanup stack may be mutated incorrectly due to lack of locking across
threads. In the static TLS model, the lock is unneeded as each thread
of execution retains its own copy of the cleanup stack.
Take the opportunity to clean up the comment block, removing the iOS
specific note as the SjLj implementation can be used outside of the
context of iOS. Convert the rest of the explanation to a doxygen style
comment block.
llvm-svn: 314632
This makes it match the definition used within llvm and in libgcc,
we previously got the wrong layout in 64 bit environments.
Differential Revision: https://reviews.llvm.org/D38247
llvm-svn: 314196
Previously most messages included a newline in the string, but a few of
them were missing. Fix these and simplify by just adding the newline in
the _LIBUNWIND_LOG macro itself.
Differential Revision: https://reviews.llvm.org/D24026
llvm-svn: 280103
This moves the majority of the unwind sources into the new project layout for
libunwind. This was previously discussed on llvmdev at [1]. This is a
purely movement related change, with the build infrastructure currently still
residing in the libc++abi repository.
[1] http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-January/081507.html
llvm-svn: 235758
Martin Storsjo