[MemProf] Make hasSingleAllocType helper non-static

As suggested in D140908, make the hasSingleAllocType helper non-static
so that it can be used in other files. Add unit testing.

Differential Revision: https://reviews.llvm.org/D144318

llvm/include/llvm/Analysis/MemoryProfileInfo.h

@@ -37,6 +37,9 @@ MDNode *getMIBStackNode(const MDNode *MIB);
 /// Returns the allocation type from an MIB metadata node.
 AllocationType getMIBAllocType(const MDNode *MIB);
 
+/// True if the AllocTypes bitmask contains just a single type.
+bool hasSingleAllocType(uint8_t AllocTypes);
+
 /// Class to build a trie of call stack contexts for a particular profiled
 /// allocation call, along with their associated allocation types.
 /// The allocation will be at the root of the trie, which is then used to

llvm/lib/Analysis/MemoryProfileInfo.cpp

@@ -91,7 +91,7 @@ static void addAllocTypeAttribute(LLVMContext &Ctx, CallBase *CI,
   CI->addFnAttr(A);
 }
 
-static bool hasSingleAllocType(uint8_t AllocTypes) {
+bool llvm::memprof::hasSingleAllocType(uint8_t AllocTypes) {
   const unsigned NumAllocTypes = llvm::popcount(AllocTypes);
   assert(NumAllocTypes != 0);
   return NumAllocTypes == 1;

llvm/unittests/Analysis/MemoryProfileInfoTest.cpp

@@ -86,6 +86,15 @@ TEST_F(MemoryProfileInfoTest, GetAllocType) {
       AllocationType::NotCold);
 }
 
+// Test the hasSingleAllocType helper.
+TEST_F(MemoryProfileInfoTest, SingleAllocType) {
+  uint8_t NotCold = (uint8_t)AllocationType::NotCold;
+  uint8_t Cold = (uint8_t)AllocationType::Cold;
+  EXPECT_TRUE(hasSingleAllocType(NotCold));
+  EXPECT_TRUE(hasSingleAllocType(Cold));
+  EXPECT_FALSE(hasSingleAllocType(NotCold | Cold));
+}
+
 // Test buildCallstackMetadata helper.
 TEST_F(MemoryProfileInfoTest, BuildCallStackMD) {
   LLVMContext C;