1 files changed, 39 insertions, 28 deletions

diff --git a/llvm/lib/Support/Threading.cpp b/llvm/lib/Support/Threading.cpp
index 48750cef5ec2..61f8ee5be5b3 100644
--- a/llvm/lib/Support/Threading.cpp
+++ b/llvm/lib/Support/Threading.cpp
@@ -45,10 +45,6 @@ void llvm::llvm_execute_on_thread(void (*Fn)(void *), void *UserData,
   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; }
@@ -57,6 +53,13 @@ void llvm::set_thread_name(const Twine &Name) {}
 
 void llvm::get_thread_name(SmallVectorImpl<char> &Name) { Name.clear(); }
 
+llvm::BitVector llvm::get_thread_affinity_mask() { return {}; }
+
+unsigned llvm::ThreadPoolStrategy::compute_thread_count() const {
+  // When threads are disabled, ensure clients will loop at least once.
+  return 1;
+}
+
 #if LLVM_ENABLE_THREADS == 0
 void llvm::llvm_execute_on_thread_async(
     llvm::unique_function<void()> Func,
@@ -78,30 +81,18 @@ void llvm::llvm_execute_on_thread_async(
 
 #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;
+int computeHostNumHardwareThreads();
+
+unsigned llvm::ThreadPoolStrategy::compute_thread_count() const {
+  int MaxThreadCount = UseHyperThreads ? computeHostNumHardwareThreads()
+                                       : sys::getHostNumPhysicalCores();
+  if (MaxThreadCount <= 0)
+    MaxThreadCount = 1;
+  if (ThreadsRequested == 0)
+    return MaxThreadCount;
+  if (!Limit)
+    return ThreadsRequested;
+  return std::min((unsigned)MaxThreadCount, ThreadsRequested);
 }
 
 namespace {
@@ -140,3 +131,23 @@ void llvm::llvm_execute_on_thread_async(
 }
 
 #endif
+
+Optional<ThreadPoolStrategy>
+llvm::get_threadpool_strategy(StringRef Num, ThreadPoolStrategy Default) {
+  if (Num == "all")
+    return llvm::hardware_concurrency();
+  if (Num.empty())
+    return Default;
+  unsigned V;
+  if (Num.getAsInteger(10, V))
+    return None; // malformed 'Num' value
+  if (V == 0)
+    return Default;
+
+  // Do not take the Default into account. This effectively disables
+  // heavyweight_hardware_concurrency() if the user asks for any number of
+  // threads on the cmd-line.
+  ThreadPoolStrategy S = llvm::hardware_concurrency();
+  S.ThreadsRequested = V;
+  return S;
+}