Initially submitted as r324356 and reverted in r324386.
This change additionally contains a fix to crashes of the buildbots.
The source of the crash was undefined behaviour caused by
std::future<> whose std::promise<> was destroyed without calling
set_value().
llvm-svn: 324575
Summary:
In the new threading model clangd creates one thread per file to manage
the AST and one thread to process each of the incoming requests.
The number of actively running threads is bounded by the semaphore to
avoid overloading the system.
Reviewers: sammccall
Reviewed By: sammccall
Subscribers: klimek, mgorny, jkorous-apple, ioeric, hintonda, cfe-commits
Differential Revision: https://reviews.llvm.org/D42573
llvm-svn: 324356
Summary:
Instead of passing Context explicitly around, we now have a thread-local
Context object `Context::current()` which is an implicit argument to
every function.
Most manipulation of this should use the WithContextValue helper, which
augments the current Context to add a single KV pair, and restores the
old context on destruction.
Advantages are:
- less boilerplate in functions that just propagate contexts
- reading most code doesn't require understanding context at all, and
using context as values in fewer places still
- fewer options to pass the "wrong" context when it changes within a
scope (e.g. when using Span)
- contexts pass through interfaces we can't modify, such as VFS
- propagating contexts across threads was slightly tricky (e.g.
copy vs move, no move-init in lambdas), and is now encapsulated in
the threadpool
Disadvantages are all the usual TLS stuff - hidden magic, and
potential for higher memory usage on threads that don't use the
context. (In practice, it's just one pointer)
Reviewers: ilya-biryukov
Subscribers: klimek, jkorous-apple, ioeric, cfe-commits
Differential Revision: https://reviews.llvm.org/D42517
llvm-svn: 323872
Summary:
We now provide an abstraction of Scheduler that abstracts threading
and resource management in ClangdServer.
No changes to behavior are intended with an exception of changed error
messages.
This patch is preliminary work to allow a revamped threading
implementation that will move the threading code out of CppFile.
Reviewers: sammccall, bkramer, jkorous-apple
Reviewed By: sammccall
Subscribers: hokein, mgorny, hintonda, ioeric, jkorous-apple, cfe-commits, klimek
Differential Revision: https://reviews.llvm.org/D42174
llvm-svn: 323851
Ilya Biryukov