[libc-commits] [libc] [libc] Remove cross-entrypoint dependencies from pthread_create (PR #225383)

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llvmorg-github-actions[bot] wrote:


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@llvm/pr-subscribers-libc

Author: Pavel Labath (labath)

<details>
<summary>Changes</summary>

pthread_create was previously calling public entrypoints (pthread_attr_init, pthread_attr_destroy, pthread_attr_getstack, pthread_attr_getguardsize, pthread_attr_getdetachstate), which violates the rule against internal cross-entrypoint dependencies.

To fix this, I create an internal header (src/pthread/pthread_attr.h) defining DEFAULT_PTHREAD_ATTR, modeled after DEFAULT_MUTEXATTR in the mutex code.

pthread_create now defaults to &DEFAULT_PTHREAD_ATTR when the attr pointer is null, and accesses the struct members directly instead of going through getter functions. This also makes it clear that getting the values cannot fail. I also update pthread_attr_init to reuse DEFAULT_PTHREAD_ATTR to avoid duplicating the default values.

While in there, update the includes to use proxy headers instead of including <pthread.h> directly, and drop the dependency on errno since pthread_create returns errors directly rather than setting errno.

Assisted-by: Gemini

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Full diff: https://github.com/llvm/llvm-project/pull/225383.diff


4 Files Affected:

- (modified) libc/src/pthread/CMakeLists.txt (+21-10) 
- (added) libc/src/pthread/pthread_attr.h (+38) 
- (modified) libc/src/pthread/pthread_attr_init.cpp (+2-12) 
- (modified) libc/src/pthread/pthread_create.cpp (+18-43) 


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</details>


https://github.com/llvm/llvm-project/pull/225383