[memprof] Add a new constructor to MemProfReader (NFC) (#116918)

This patch adds a new constructor to MemProfReader that takes
IndexedMemProfData, a complete package of MemProf profile.  To
showcase its usage, I'm updating one of the unit tests to use the new
constructor.

Because of type mismatches between DenseMap and MapVector, I'm copying
Frames and CallStacks for now.  Once we remove the methods and old
constructors that take or return individual components (frames, call
stacks, and records), we will drop the copying, and the new
constructor will collapse down to:

  MemProfReader(IndexedMemProfData MemProfData)
    : MemProfData(std::move(MemProfData)) {}

Since nobody in the LLVM codebase uses the constructor that takes the
three indivdual components, I'm deprecating the old constructor.

Author: kazutakahirata

llvm/include/llvm/ProfileData/MemProfReader.h

@@ -120,13 +120,24 @@ class MemProfReader {
 
   // Initialize the MemProfReader with the frame mappings, call stack mappings,
   // and profile contents.
+  LLVM_DEPRECATED("Construct MemProfReader with IndexedMemProfData",
+                  "MemProfReader")
   MemProfReader(
       llvm::DenseMap<FrameId, Frame> FrameIdMap,
       llvm::DenseMap<CallStackId, llvm::SmallVector<FrameId>> CSIdMap,
       llvm::MapVector<GlobalValue::GUID, IndexedMemProfRecord> ProfData)
       : IdToFrame(std::move(FrameIdMap)), CSIdToCallStack(std::move(CSIdMap)),
         FunctionProfileData(std::move(ProfData)) {}
 
+  // Initialize the MemProfReader with the given MemProf profile.
+  MemProfReader(IndexedMemProfData MemProfData) {
+    for (const auto &[FrameId, F] : MemProfData.Frames)
+      IdToFrame.try_emplace(FrameId, F);
+    for (const auto &[CSId, CS] : MemProfData.CallStacks)
+      CSIdToCallStack.try_emplace(CSId, CS);
+    FunctionProfileData = std::move(MemProfData.Records);
+  }
+
 protected:
   // A helper method to extract the frame from the IdToFrame map.
   const Frame &idToFrame(const FrameId Id) const {

llvm/unittests/ProfileData/MemProfTest.cpp

@@ -490,30 +490,28 @@ TEST(MemProf, BaseMemProfReader) {
 }
 
 TEST(MemProf, BaseMemProfReaderWithCSIdMap) {
-  llvm::DenseMap<FrameId, Frame> FrameIdMap;
+  llvm::memprof::IndexedMemProfData MemProfData;
   Frame F1(/*Hash=*/IndexedMemProfRecord::getGUID("foo"), /*LineOffset=*/20,
            /*Column=*/5, /*IsInlineFrame=*/true);
   Frame F2(/*Hash=*/IndexedMemProfRecord::getGUID("bar"), /*LineOffset=*/10,
            /*Column=*/2, /*IsInlineFrame=*/false);
-  FrameIdMap.insert({F1.hash(), F1});
-  FrameIdMap.insert({F2.hash(), F2});
+  MemProfData.Frames.insert({F1.hash(), F1});
+  MemProfData.Frames.insert({F2.hash(), F2});
 
-  llvm::DenseMap<CallStackId, llvm::SmallVector<FrameId>> CSIdMap;
   llvm::SmallVector<FrameId> CallStack = {F1.hash(), F2.hash()};
   CallStackId CSId = llvm::memprof::hashCallStack(CallStack);
-  CSIdMap.insert({CSId, CallStack});
+  MemProfData.CallStacks.insert({CSId, CallStack});
 
-  llvm::MapVector<llvm::GlobalValue::GUID, IndexedMemProfRecord> ProfData;
   IndexedMemProfRecord FakeRecord;
   MemInfoBlock Block;
   Block.AllocCount = 1U, Block.TotalAccessDensity = 4,
   Block.TotalLifetime = 200001;
   FakeRecord.AllocSites.emplace_back(
       /*CSId=*/llvm::memprof::hashCallStack(CallStack),
       /*MB=*/Block);
-  ProfData.insert({F1.hash(), FakeRecord});
+  MemProfData.Records.insert({F1.hash(), FakeRecord});
 
-  MemProfReader Reader(FrameIdMap, CSIdMap, ProfData);
+  MemProfReader Reader(MemProfData);
 
   llvm::SmallVector<MemProfRecord, 1> Records;
   for (const auto &KeyRecordPair : Reader) {