[memprof] Move Frame::hash and hashCallStack to IndexedMemProfData (NFC)

[kazutakahirata]

Now that IndexedMemProfData::{addFrame,addCallStack} are the only
callers of Frame::hash and hashCallStack, respectively, this patch
moves those functions into IndexedMemProfData and makes them private.
With this patch, we can obtain FrameId and CallStackId only through
addFrame and addCallStack, respectively.

[llvmbot]

@llvm/pr-subscribers-pgo

Author: Kazu Hirata (kazutakahirata)

Changes

Now that IndexedMemProfData::{addFrame,addCallStack} are the only
callers of Frame::hash and hashCallStack, respectively, this patch
moves those functions into IndexedMemProfData and makes them private.
With this patch, we can obtain FrameId and CallStackId only through
addFrame and addCallStack, respectively.

---

Full diff: https://github.com/llvm/llvm-project/pull/120365.diff

2 Files Affected:

• (modified) llvm/include/llvm/ProfileData/MemProf.h (+20-19)
• (modified) llvm/lib/ProfileData/MemProf.cpp (+1-1)

diff --git a/llvm/include/llvm/ProfileData/MemProf.h b/llvm/include/llvm/ProfileData/MemProf.h
index ef96b74c9d400c..883e24d7186152 100644
--- a/llvm/include/llvm/ProfileData/MemProf.h
+++ b/llvm/include/llvm/ProfileData/MemProf.h
@@ -323,21 +323,6 @@ struct Frame {
        << "        Column: " << Column << "\n"
        << "        Inline: " << IsInlineFrame << "\n";
   }
-
-  // Return a hash value based on the contents of the frame. Here we use a
-  // cryptographic hash function to minimize the chance of hash collisions.  We
-  // do persist FrameIds as part of memprof formats up to Version 2, inclusive.
-  // However, the deserializer never calls this function; it uses FrameIds
-  // merely as keys to look up Frames proper.
-  inline FrameId hash() const {
-    llvm::HashBuilder<llvm::TruncatedBLAKE3<8>, llvm::endianness::little>
-        HashBuilder;
-    HashBuilder.add(Function, LineOffset, Column, IsInlineFrame);
-    llvm::BLAKE3Result<8> Hash = HashBuilder.final();
-    FrameId Id;
-    std::memcpy(&Id, Hash.data(), sizeof(Hash));
-    return Id;
-  }
 };
 
 // A type representing the index into the table of call stacks.
@@ -775,9 +760,6 @@ class CallStackLookupTrait {
   }
 };
 
-// Compute a CallStackId for a given call stack.
-CallStackId hashCallStack(ArrayRef<FrameId> CS);
-
 namespace detail {
 // "Dereference" the iterator from DenseMap or OnDiskChainedHashTable.  We have
 // to do so in one of two different ways depending on the type of the hash
@@ -1011,7 +993,7 @@ struct IndexedMemProfData {
   llvm::MapVector<CallStackId, llvm::SmallVector<FrameId>> CallStacks;
 
   FrameId addFrame(const Frame &F) {
-    const FrameId Id = F.hash();
+    const FrameId Id = hashFrame(F);
     Frames.try_emplace(Id, F);
     return Id;
   }
@@ -1027,6 +1009,25 @@ struct IndexedMemProfData {
     CallStacks.try_emplace(CSId, std::move(CS));
     return CSId;
   }
+
+private:
+  // Return a hash value based on the contents of the frame. Here we use a
+  // cryptographic hash function to minimize the chance of hash collisions.  We
+  // do persist FrameIds as part of memprof formats up to Version 2, inclusive.
+  // However, the deserializer never calls this function; it uses FrameIds
+  // merely as keys to look up Frames proper.
+  FrameId hashFrame(const Frame &F) const {
+    llvm::HashBuilder<llvm::TruncatedBLAKE3<8>, llvm::endianness::little>
+        HashBuilder;
+    HashBuilder.add(F.Function, F.LineOffset, F.Column, F.IsInlineFrame);
+    llvm::BLAKE3Result<8> Hash = HashBuilder.final();
+    FrameId Id;
+    std::memcpy(&Id, Hash.data(), sizeof(Hash));
+    return Id;
+  }
+
+  // Compute a CallStackId for a given call stack.
+  CallStackId hashCallStack(ArrayRef<FrameId> CS) const;
 };
 
 struct FrameStat {
diff --git a/llvm/lib/ProfileData/MemProf.cpp b/llvm/lib/ProfileData/MemProf.cpp
index 1c240c3858cc76..15ab44934bbf0b 100644
--- a/llvm/lib/ProfileData/MemProf.cpp
+++ b/llvm/lib/ProfileData/MemProf.cpp
@@ -290,7 +290,7 @@ Expected<MemProfSchema> readMemProfSchema(const unsigned char *&Buffer) {
   return Result;
 }
 
-CallStackId hashCallStack(ArrayRef<FrameId> CS) {
+CallStackId IndexedMemProfData::hashCallStack(ArrayRef<FrameId> CS) const {
   llvm::HashBuilder<llvm::TruncatedBLAKE3<8>, llvm::endianness::little>
       HashBuilder;
   for (FrameId F : CS)