diff --git a/llvm/lib/ProfileData/SampleProfReader.cpp b/llvm/lib/ProfileData/SampleProfReader.cpp
--- a/llvm/lib/ProfileData/SampleProfReader.cpp
+++ b/llvm/lib/ProfileData/SampleProfReader.cpp
@@ -765,9 +765,8 @@
   // If profile is CS, the function offset section is expected to consist of
   // sequences of contexts in pre-order layout
   // (e.g. [A, A:1 @ B, A:1 @ B:2.3 @ C] [D, D:1 @ E]), so that when a matched
-  // context in the module is found, the profiles of all its prefix contexts (
-  // all callers on the call stack) are loaded. A list is needed since the order
-  // of profiles matters.
+  // context in the module is found, the profiles of all its callees are
+  // recursively loaded. A list is needed since the order of profiles matters.
   if (ProfileIsCS)
     return true;
 
@@ -861,6 +860,7 @@
     }
 
     if (ProfileIsCS) {
+      assert(useFuncOffsetList());
       DenseSet<uint64_t> FuncGuidsToUse;
       if (useMD5()) {
         for (auto Name : FuncsToUse)
@@ -898,6 +898,7 @@
         }
       }
     } else if (useMD5()) {
+      assert(!useFuncOffsetList());
       for (auto Name : FuncsToUse) {
         auto GUID = std::to_string(MD5Hash(Name));
         auto iter = FuncOffsetTable.find(StringRef(GUID));
@@ -908,6 +909,7 @@
           return EC;
       }
     } else if (Remapper) {
+      assert(useFuncOffsetList());
       for (auto NameOffset : FuncOffsetList) {
         SampleContext FContext(NameOffset.first);
         auto FuncName = FContext.getName();
@@ -918,6 +920,7 @@
           return EC;
       }
     } else {
+      assert(!useFuncOffsetList());
       for (auto Name : FuncsToUse) {
         auto iter = FuncOffsetTable.find(Name);
         if (iter == FuncOffsetTable.end())