gperftools/cmake
Aliaksey Kandratsenka 6691226953 split and rewrite TLS access for thread caches
Logic was removed from thread_cache.{h,cc} into
thread_cache_ptr.{h,cc}.

Separation will help possible future evolution, and we already changed
the logic quite a bit:

* early access (when TLS isn't initialized yet) now uses global
ThreadCache instance. We therefore have ThreadCachePtr instances
managing required locking. This eliminates unnecessary complication of
PTHREADS_CRASHES_IF_RUN_TOO_EARLY logic, and any other danger of
touching TLS too early. BTW previous implementation actually leaked
initial early-initialized ThreadCache instance(!)

* old configure-time HAVE_TLS logic is amputated. Config-time part of
it made little sense as C++ 17 guarantees availability of
thread_local, but we have manually curated deny-list of "bad" OSes,
that we tested (via compile checks!) at configure time. Now this
is all compile time. There is now compile-time kHaveGoodTLS variable
and we're using it mostly via if constexpr.

* kHaveGoodTLS case of creating thread cache is simplified and made
more straightforward (no need to have in_setspecific logic).

* !kHaveGoodTLS case if fixed and improved too. We avoid
std:🧵:get_id, as it deadlocks on mingw. We use errno address as
a portable and (usually) async-signal safe 'my thread' identifier. We
also eliminate linear searching of thread's cache and replace it with
straightforward hash table lookup.
2024-02-03 15:57:14 -05:00
..
config.h.in split and rewrite TLS access for thread caches 2024-02-03 15:57:14 -05:00
DefineTargetVariables.cmake DefineTargetVariables.cmake: fix for macOS 2023-11-25 16:05:47 +08:00
pkgconfig.pc Update cmake 2020-12-19 18:52:40 -08:00
tcmalloc.h.in bump required c++ standard to c++-17 2024-01-30 15:54:24 -05:00