1 files changed, 95 insertions, 0 deletions
diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
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+++ b/llvm/lib/Support/Threading.cpp
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+//===-- llvm/Support/Threading.cpp- Control multithreading mode --*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines helper functions for running LLVM in a multi-threaded
+// environment.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Threading.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Host.h"
+
+#include <cassert>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
+
+bool llvm::llvm_is_multithreaded() {
+#if LLVM_ENABLE_THREADS != 0
+  return true;
+#else
+  return false;
+#endif
+}
+
+#if LLVM_ENABLE_THREADS == 0 ||                                                \
+    (!defined(_WIN32) && !defined(HAVE_PTHREAD_H))
+// Support for non-Win32, non-pthread implementation.
+void llvm::llvm_execute_on_thread(void (*Fn)(void *), void *UserData,
+                                  unsigned RequestedStackSize) {
+  (void)RequestedStackSize;
+  Fn(UserData);
+}
+
+unsigned llvm::heavyweight_hardware_concurrency() { return 1; }
+
+unsigned llvm::hardware_concurrency() { return 1; }
+
+uint64_t llvm::get_threadid() { return 0; }
+
+uint32_t llvm::get_max_thread_name_length() { return 0; }
+
+void llvm::set_thread_name(const Twine &Name) {}
+
+void llvm::get_thread_name(SmallVectorImpl<char> &Name) { Name.clear(); }
+
+#else
+
+#include <thread>
+unsigned llvm::heavyweight_hardware_concurrency() {
+  // Since we can't get here unless LLVM_ENABLE_THREADS == 1, it is safe to use
+  // `std::thread` directly instead of `llvm::thread` (and indeed, doing so
+  // allows us to not define `thread` in the llvm namespace, which conflicts
+  // with some platforms such as FreeBSD whose headers also define a struct
+  // called `thread` in the global namespace which can cause ambiguity due to
+  // ADL.
+  int NumPhysical = sys::getHostNumPhysicalCores();
+  if (NumPhysical == -1)
+    return std::thread::hardware_concurrency();
+  return NumPhysical;
+}
+
+unsigned llvm::hardware_concurrency() {
+#if defined(HAVE_SCHED_GETAFFINITY) && defined(HAVE_CPU_COUNT)
+  cpu_set_t Set;
+  if (sched_getaffinity(0, sizeof(Set), &Set))
+    return CPU_COUNT(&Set);
+#endif
+  // Guard against std::thread::hardware_concurrency() returning 0.
+  if (unsigned Val = std::thread::hardware_concurrency())
+    return Val;
+  return 1;
+}
+
+// Include the platform-specific parts of this class.
+#ifdef LLVM_ON_UNIX
+#include "Unix/Threading.inc"
+#endif
+#ifdef _WIN32
+#include "Windows/Threading.inc"
+#endif
+
+#endif