Index: lib/profile/InstrProfilingWriter.c
===================================================================
--- lib/profile/InstrProfilingWriter.c
+++ lib/profile/InstrProfilingWriter.c
@@ -91,6 +91,15 @@
   return 0;
 }
 
+static int hasNoValueSites(const __llvm_profile_data *DataBegin,
+                           const __llvm_profile_data *DataEnd) {
+  for (; DataBegin != DataEnd; ++DataBegin)
+    for (int I = 0; I <= IPVK_Last; I++)
+      if (DataBegin->NumValueSites[I] != 0)
+        return 0;
+  return 1;
+}
+
 #define VP_BUFFER_SIZE 8 * 1024
 static int writeValueProfData(WriterCallback Writer, void *WriterCtx,
                               VPGatherHookType VPDataGatherer,
@@ -100,7 +109,10 @@
   uint32_t BufferSz;
   const __llvm_profile_data *DI = 0;
 
-  if (!VPDataGatherer)
+  /* Bail out early so that we don't attempt to call any memory allocation
+   * functions.
+   */
+  if (!VPDataGatherer || hasNoValueSites(DataBegin, DataEnd))
     return 0;
 
   BufferSz = VPBufferSize ? VPBufferSize : VP_BUFFER_SIZE;