d87eea35fa
This is the first step in preparation for: https://discourse.llvm.org/t/rfc-make-clang-builtin-math-functions-constexpr-with-llvm-libc-to-support-c-23-constexpr-math-functions/86450
89 lines
2.8 KiB
C++
89 lines
2.8 KiB
C++
//===-- Linux implementation of the pthread_create function ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "pthread_create.h"
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#include "pthread_attr_destroy.h"
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#include "pthread_attr_init.h"
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#include "pthread_attr_getdetachstate.h"
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#include "pthread_attr_getguardsize.h"
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#include "pthread_attr_getstack.h"
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#include "src/__support/common.h"
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#include "src/__support/libc_errno.h"
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#include "src/__support/macros/config.h"
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#include "src/__support/macros/optimization.h"
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#include "src/__support/threads/thread.h"
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#include <pthread.h> // For pthread_* type definitions.
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namespace LIBC_NAMESPACE_DECL {
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static_assert(sizeof(pthread_t) == sizeof(LIBC_NAMESPACE::Thread),
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"Mismatch between pthread_t and internal Thread.");
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LLVM_LIBC_FUNCTION(int, pthread_create,
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(pthread_t *__restrict th,
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const pthread_attr_t *__restrict attr,
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__pthread_start_t func, void *arg)) {
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pthread_attr_t default_attr;
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if (attr == nullptr) {
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// We failed to initialize attributes (should be impossible)
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if (LIBC_UNLIKELY(LIBC_NAMESPACE::pthread_attr_init(&default_attr) != 0))
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return EINVAL;
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attr = &default_attr;
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}
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void *stack;
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size_t stacksize, guardsize;
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int detachstate;
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// As of writing this all the `pthread_attr_get*` functions always succeed.
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if (LIBC_UNLIKELY(
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LIBC_NAMESPACE::pthread_attr_getstack(attr, &stack, &stacksize) != 0))
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return EINVAL;
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if (LIBC_UNLIKELY(
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LIBC_NAMESPACE::pthread_attr_getguardsize(attr, &guardsize) != 0))
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return EINVAL;
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if (LIBC_UNLIKELY(
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LIBC_NAMESPACE::pthread_attr_getdetachstate(attr, &detachstate) != 0))
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return EINVAL;
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if (attr == &default_attr)
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// Should we fail here? Its non-issue as the moment as pthread_attr_destroy
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// can only succeed.
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if (LIBC_UNLIKELY(LIBC_NAMESPACE::pthread_attr_destroy(&default_attr) != 0))
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return EINVAL;
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if (stacksize && stacksize < PTHREAD_STACK_MIN)
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return EINVAL;
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if (guardsize % EXEC_PAGESIZE != 0)
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return EINVAL;
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if (detachstate != PTHREAD_CREATE_DETACHED &&
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detachstate != PTHREAD_CREATE_JOINABLE)
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return EINVAL;
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// Thread::run will check validity of the `stack` argument (stack alignment is
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// universal, not sure a pthread requirement).
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auto *thread = reinterpret_cast<LIBC_NAMESPACE::Thread *>(th);
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int result = thread->run(func, arg, stack, stacksize, guardsize,
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detachstate == PTHREAD_CREATE_DETACHED);
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if (result != 0 && result != EPERM && result != EINVAL)
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return EAGAIN;
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return result;
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}
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} // namespace LIBC_NAMESPACE_DECL
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