Add computeHostNumPhysicalCores() implementation for Darwin

Differential Revision: https://reviews.llvm.org/D25800

llvm-svn: 284656

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/lib/Support/Host.cpp b/llvm/lib/Support/Host.cpp
index e4a9b504a76..dd19eee15f6 100644
--- a/llvm/lib/Support/Host.cpp
+++ b/llvm/lib/Support/Host.cpp
@@ -1234,6 +1234,25 @@ static int computeHostNumPhysicalCores() {
   }
   return UniqueItems.size();
 }
+#elif defined(__APPLE__) && defined(__x86_64__)
+#include <sys/param.h>
+#include <sys/sysctl.h>
+
+// Gets the number of *physical cores* on the machine.
+static int computeHostNumPhysicalCores() {
+  uint32_t count;
+  size_t len = sizeof(count);
+  sysctlbyname("hw.physicalcpu", &count, &len, NULL, 0);
+  if (count < 1) {
+    int nm[2];
+    nm[0] = CTL_HW;
+    nm[1] = HW_AVAILCPU;
+    sysctl(nm, 2, &count, &len, NULL, 0);
+    if (count < 1)
+      return -1;
+  }
+  return count;
+}
 #else
 // On other systems, return -1 to indicate unknown.
 static int computeHostNumPhysicalCores() { return -1; }