Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/Support/Threading.h b/linux-x64/clang/include/llvm/Support/Threading.h
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+//===-- llvm/Support/Threading.h - Control multithreading mode --*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares helper functions for running LLVM in a multi-threaded
+// environment.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_THREADING_H
+#define LLVM_SUPPORT_THREADING_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX
+#include "llvm/Support/Compiler.h"
+#include <ciso646> // So we can check the C++ standard lib macros.
+#include <functional>
+
+#if defined(_MSC_VER)
+// MSVC's call_once implementation worked since VS 2015, which is the minimum
+// supported version as of this writing.
+#define LLVM_THREADING_USE_STD_CALL_ONCE 1
+#elif defined(LLVM_ON_UNIX) && \
+ (defined(_LIBCPP_VERSION) || \
+ !(defined(__NetBSD__) || defined(__OpenBSD__) || defined(__ppc__)))
+// std::call_once from libc++ is used on all Unix platforms. Other
+// implementations like libstdc++ are known to have problems on NetBSD,
+// OpenBSD and PowerPC.
+#define LLVM_THREADING_USE_STD_CALL_ONCE 1
+#else
+#define LLVM_THREADING_USE_STD_CALL_ONCE 0
+#endif
+
+#if LLVM_THREADING_USE_STD_CALL_ONCE
+#include <mutex>
+#else
+#include "llvm/Support/Atomic.h"
+#endif
+
+namespace llvm {
+class Twine;
+
+/// Returns true if LLVM is compiled with support for multi-threading, and
+/// false otherwise.
+bool llvm_is_multithreaded();
+
+/// llvm_execute_on_thread - Execute the given \p UserFn on a separate
+/// thread, passing it the provided \p UserData and waits for thread
+/// completion.
+///
+/// This function does not guarantee that the code will actually be executed
+/// on a separate thread or honoring the requested stack size, but tries to do
+/// so where system support is available.
+///
+/// \param UserFn - The callback to execute.
+/// \param UserData - An argument to pass to the callback function.
+/// \param RequestedStackSize - If non-zero, a requested size (in bytes) for
+/// the thread stack.
+void llvm_execute_on_thread(void (*UserFn)(void *), void *UserData,
+ unsigned RequestedStackSize = 0);
+
+#if LLVM_THREADING_USE_STD_CALL_ONCE
+
+ typedef std::once_flag once_flag;
+
+#else
+
+ enum InitStatus { Uninitialized = 0, Wait = 1, Done = 2 };
+
+ /// \brief The llvm::once_flag structure
+ ///
+ /// This type is modeled after std::once_flag to use with llvm::call_once.
+ /// This structure must be used as an opaque object. It is a struct to force
+ /// autoinitialization and behave like std::once_flag.
+ struct once_flag {
+ volatile sys::cas_flag status = Uninitialized;
+ };
+
+#endif
+
+ /// \brief Execute the function specified as a parameter once.
+ ///
+ /// Typical usage:
+ /// \code
+ /// void foo() {...};
+ /// ...
+ /// static once_flag flag;
+ /// call_once(flag, foo);
+ /// \endcode
+ ///
+ /// \param flag Flag used for tracking whether or not this has run.
+ /// \param F Function to call once.
+ template <typename Function, typename... Args>
+ void call_once(once_flag &flag, Function &&F, Args &&... ArgList) {
+#if LLVM_THREADING_USE_STD_CALL_ONCE
+ std::call_once(flag, std::forward<Function>(F),
+ std::forward<Args>(ArgList)...);
+#else
+ // For other platforms we use a generic (if brittle) version based on our
+ // atomics.
+ sys::cas_flag old_val = sys::CompareAndSwap(&flag.status, Wait, Uninitialized);
+ if (old_val == Uninitialized) {
+ std::forward<Function>(F)(std::forward<Args>(ArgList)...);
+ sys::MemoryFence();
+ TsanIgnoreWritesBegin();
+ TsanHappensBefore(&flag.status);
+ flag.status = Done;
+ TsanIgnoreWritesEnd();
+ } else {
+ // Wait until any thread doing the call has finished.
+ sys::cas_flag tmp = flag.status;
+ sys::MemoryFence();
+ while (tmp != Done) {
+ tmp = flag.status;
+ sys::MemoryFence();
+ }
+ }
+ TsanHappensAfter(&flag.status);
+#endif
+ }
+
+ /// Get the amount of currency to use for tasks requiring significant
+ /// memory or other resources. Currently based on physical cores, if
+ /// available for the host system, otherwise falls back to
+ /// thread::hardware_concurrency().
+ /// Returns 1 when LLVM is configured with LLVM_ENABLE_THREADS=OFF
+ unsigned heavyweight_hardware_concurrency();
+
+ /// Get the number of threads that the current program can execute
+ /// concurrently. On some systems std::thread::hardware_concurrency() returns
+ /// the total number of cores, without taking affinity into consideration.
+ /// Returns 1 when LLVM is configured with LLVM_ENABLE_THREADS=OFF.
+ /// Fallback to std::thread::hardware_concurrency() if sched_getaffinity is
+ /// not available.
+ unsigned hardware_concurrency();
+
+ /// \brief Return the current thread id, as used in various OS system calls.
+ /// Note that not all platforms guarantee that the value returned will be
+ /// unique across the entire system, so portable code should not assume
+ /// this.
+ uint64_t get_threadid();
+
+ /// \brief Get the maximum length of a thread name on this platform.
+ /// A value of 0 means there is no limit.
+ uint32_t get_max_thread_name_length();
+
+ /// \brief Set the name of the current thread. Setting a thread's name can
+ /// be helpful for enabling useful diagnostics under a debugger or when
+ /// logging. The level of support for setting a thread's name varies
+ /// wildly across operating systems, and we only make a best effort to
+ /// perform the operation on supported platforms. No indication of success
+ /// or failure is returned.
+ void set_thread_name(const Twine &Name);
+
+ /// \brief Get the name of the current thread. The level of support for
+ /// getting a thread's name varies wildly across operating systems, and it
+ /// is not even guaranteed that if you can successfully set a thread's name
+ /// that you can later get it back. This function is intended for diagnostic
+ /// purposes, and as with setting a thread's name no indication of whether
+ /// the operation succeeded or failed is returned.
+ void get_thread_name(SmallVectorImpl<char> &Name);
+}
+
+#endif