llvm-project.git/libc/src/__support/threads/thread.cpp, branch users/mingmingl-llvm/samplefdo-profile-format Unnamed repository; edit this file 'description' to name the repository. [libc] ensure tls dtors are called in main thread (#133641) 2025-09-03T13:02:03+00:00 Schrodinger ZHU Yifan yifanzhu@rochester.edu 2025-09-03T13:02:03+00:00 71641049a91253f7547f792ec2fcb6609794ea4f This is a part of allocator patch since I want to make sure the TLS for allocators are correctly handled. TLS dtors are not invoked on exit previously. This departures from major libc implementations. This PR fixes the issue by aligning the behavior with bionic. https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/bionic/exit.cpp I believe the finalization order is also consistent with glibc now: On main thread exiting: - pthread_key dtors are not called (unless exiting with `pthread_exit`) - `__cxa` based tls dtors are called - `::__cxa_atexit` and `::atexit` dtors are called - `.fini` dtors are called ![image](https://github.com/user-attachments/assets/737c4845-cab6-47a9-aa00-32997be141bd) 
This is a part of allocator patch since I want to make sure the TLS for
allocators are correctly handled.

TLS dtors are not invoked on exit previously. This departures from major
libc implementations.

This PR fixes the issue by aligning the behavior with bionic.


https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/bionic/exit.cpp

I believe the finalization order is also consistent with glibc now:

On main thread exiting:

- pthread_key dtors are not called (unless exiting with `pthread_exit`)
- `__cxa` based tls dtors are called
- `::__cxa_atexit` and `::atexit` dtors are called
- `.fini` dtors are called


![image](https://github.com/user-attachments/assets/737c4845-cab6-47a9-aa00-32997be141bd)
 [libc] Fix return value of __cxa_thread_atexit_impl function. (#122171) 2025-01-09T05:47:58+00:00 Alexey Samsonov vonosmas@gmail.com 2025-01-09T05:47:58+00:00 b30f9d74d6a0f735ef597b1acae73daac2d7df39 This has been added in 0071a79532e8d664b734956a431d8c8c942cc25e to support TLS destructors. Return value of __cxa_thread_atexit is supposed to be the same as std::atexit - zero on success, non-zero on failure. Update the code to do just that (also be consistent with llvm-libc's existing atexit / at_quick_exit implementations). 
This has been added in 0071a79532e8d664b734956a431d8c8c942cc25e to
support TLS destructors. Return value of __cxa_thread_atexit is supposed
to be the same as std::atexit - zero on success, non-zero on failure.
Update the code to do just that (also be consistent with llvm-libc's
existing atexit / at_quick_exit implementations).
 [libc] inline thread self (#101739) 2024-08-02T20:11:17+00:00 Schrodinger ZHU Yifan yifanzhu@rochester.edu 2024-08-02T20:11:17+00:00 4ac24b388a5d812c57d50ed8ce336f1d516450cc The codegen for non-inlined version is "quite ugly" as it emits some checks to make sure the initialization routine is properly executed because the compiler does not see how the TLS object is initialized. This leads to some `callq 0x0` junk in the final outputs. For codegen details, see https://godbolt.org/z/rb5qYj3vY. 
The codegen for non-inlined version is "quite ugly" as it emits some
checks to make sure the initialization routine is properly executed
because the compiler does not see how the TLS object is initialized.
This leads to some `callq 0x0` junk in the final outputs.

For codegen details, see https://godbolt.org/z/rb5qYj3vY.
 [libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98597) 2024-07-12T16:28:41+00:00 Petr Hosek phosek@google.com 2024-07-12T16:28:41+00:00 5ff3ff33ff930e4ec49da7910612d8a41eb068cb This is a part of #97655. 
This is a part of #97655.
 Revert "[libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration" (#98593) 2024-07-12T07:12:13+00:00 Mehdi Amini joker.eph@gmail.com 2024-07-12T07:12:13+00:00 ce9035f5bd3aa09cbd899489cdbc7f6c18acf1e3 Reverts llvm/llvm-project#98075 bots are broken 
Reverts llvm/llvm-project#98075

bots are broken
 [libc] Migrate to using LIBC_NAMESPACE_DECL for namespace declaration (#98075) 2024-07-11T19:35:22+00:00 Petr Hosek phosek@google.com 2024-07-11T19:35:22+00:00 3f30effe1bd81fa1b039218a9bfe79c3b03fafad This is a part of #97655. 
This is a part of #97655.
 [libc] rework mutex (#92168) 2024-06-01T01:57:18+00:00 Schrodinger ZHU Yifan yifanzhu@rochester.edu 2024-06-01T01:57:18+00:00 142afde0eba4940f2b331274e9a3535fee960f35 






[libc] Replace `MutexLock` with `cpp::lock_guard` (#89340)
2024-05-09T07:06:18+00:00

Vlad Mishel
43666597+vmishelcs@users.noreply.github.com

2024-05-09T07:06:18+00:00

c4a3d184db5fdffe798208b8281dfe944616f9ed

This PR address issue #89002.

#### Changes in this PR

* Added a simple implementation of `cpp::lock_guard` (an equivalent of
`std::lock_guard`) in libc/src/__support/CPP inspired by the libstdc++
implementation
* Added tests for `cpp::lock_guard` in
/libc/test/src/__support/CPP/mutex_test.cpp
* Replaced all references to `MutexLock` with `cpp::lock_guard`

---------

Co-authored-by: Guillaume Chatelet <gchatelet@google.com>




This PR address issue #89002.

#### Changes in this PR

* Added a simple implementation of `cpp::lock_guard` (an equivalent of
`std::lock_guard`) in libc/src/__support/CPP inspired by the libstdc++
implementation
* Added tests for `cpp::lock_guard` in
/libc/test/src/__support/CPP/mutex_test.cpp
* Replaced all references to `MutexLock` with `cpp::lock_guard`

---------

Co-authored-by: Guillaume Chatelet <gchatelet@google.com>






[libc] clean up futex usage (#91163)
2024-05-07T14:47:41+00:00

Schrodinger ZHU Yifan
yifanzhu@rochester.edu

2024-05-07T14:47:41+00:00

ab3a9e724d87a4272782f76b90fb0872a6a86939

# Motivation

Futex syscalls are widely used in our codebase as synchronization
mechanism. Hence, it may be worthy to abstract out the most common
routines (wait and wake). On the other hand, C++20 also provides
`std::atomic_notify_one/std::atomic_wait/std::atomic_notify_all` which
align with such functionalities. This PR introduces `Futex` as a subtype
of `cpp::Atomic<FutexWordType>` with additional
`notify_one/notify_all/wait` operations.

Providing such wrappers also make future porting easier. For example,
FreeBSD's `_umtx_op` and Darwin's `ulock` can be wrapped in a similar
manner.

### Similar Examples

1. [bionic
futex](https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/bionic/bionic_futex.cpp)
2. [futex in Rust's
std](https://github.com/rust-lang/rust/blob/8cef37dbb67e9c80702925f19cf298c4203991e4/library/std/src/sys/pal/unix/futex.rs#L21)




# Motivation

Futex syscalls are widely used in our codebase as synchronization
mechanism. Hence, it may be worthy to abstract out the most common
routines (wait and wake). On the other hand, C++20 also provides
`std::atomic_notify_one/std::atomic_wait/std::atomic_notify_all` which
align with such functionalities. This PR introduces `Futex` as a subtype
of `cpp::Atomic<FutexWordType>` with additional
`notify_one/notify_all/wait` operations.

Providing such wrappers also make future porting easier. For example,
FreeBSD's `_umtx_op` and Darwin's `ulock` can be wrapped in a similar
manner.

### Similar Examples

1. [bionic
futex](https://android.googlesource.com/platform/bionic/+/refs/heads/main/libc/bionic/bionic_futex.cpp)
2. [futex in Rust's
std](https://github.com/rust-lang/rust/blob/8cef37dbb67e9c80702925f19cf298c4203991e4/library/std/src/sys/pal/unix/futex.rs#L21)






[libc] Mass replace enclosing namespace (#67032)
2023-09-26T09:45:04+00:00

Guillaume Chatelet
gchatelet@google.com

2023-09-26T09:45:04+00:00

b6bc9d72f65a5086f310f321e969d96e9a559e75

This is step 4 of
https://discourse.llvm.org/t/rfc-customizable-namespace-to-allow-testing-the-libc-when-the-system-libc-is-also-llvms-libc/73079




This is step 4 of
https://discourse.llvm.org/t/rfc-customizable-namespace-to-allow-testing-the-libc-when-the-system-libc-is-also-llvms-libc/73079