llvm-6502/include/llvm/Support/Threading.h
2014-10-14 09:34:16 +00:00

70 lines
2.2 KiB
C++

//===-- 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
#if !defined(__MINGW__)
#include <mutex>
#endif
namespace llvm {
/// 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.
///
/// 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);
/// \brief Execute the function specified as a template parameter once.
///
/// Calls \p UserFn once ever. The call uniqueness is based on the address of
/// the function passed in via the template arguement. This means no matter how
/// many times you call llvm_call_once<foo>() in the same or different
/// locations, foo will only be called once.
///
/// Typical usage:
/// \code
/// void foo() {...};
/// ...
/// llvm_call_once<foo>();
/// \endcode
///
/// \tparam UserFn Function to call once.
template <void (*UserFn)(void)> void llvm_call_once() {
#if !defined(__MINGW__)
static std::once_flag flag;
std::call_once(flag, UserFn);
#else
struct InitOnceWrapper {
InitOnceWrapper() { UserFn(); }
};
static InitOnceWrapper InitOnceVar;
#endif
}
}
#endif