[llvm] [memprof] Remove const from the return type of toMemProfRecord (PR #93415)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/93415

"const" being removed in this patch prevents the move semantics from
being used in:

  AI.CallStack = Callback(IndexedAI.CSId);

With this patch on an indexed MemProf Version 2 profile, the cycle
count and instruction count go down by 13.3% and 26.3%, respectively,
with "llvm-profdata show" modified to deserialize all MemProfRecords.

>From 4f5fb908add38517138d2989992d1a54d130ab77 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sat, 25 May 2024 23:27:54 -0700
Subject: [PATCH] [memprof] Remove const from the return type of
 toMemProfRecord

"const" being removed in this patch prevents the move semantics from
being used in:

  AI.CallStack = Callback(IndexedAI.CSId);

With this patch on an indexed MemProf Version 2 profile, the cycle
count and instruction count go down by 13.3% and 26.3%, respectively,
with "llvm-profdata show" modified to deserialize all MemProfRecords.
---
 llvm/include/llvm/ProfileData/MemProf.h | 4 ++--
 llvm/lib/ProfileData/MemProf.cpp        | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/ProfileData/MemProf.h b/llvm/include/llvm/ProfileData/MemProf.h
index 66a99f16cdb63..17cef15344285 100644
--- a/llvm/include/llvm/ProfileData/MemProf.h
+++ b/llvm/include/llvm/ProfileData/MemProf.h
@@ -426,8 +426,8 @@ struct IndexedMemProfRecord {
   // Convert IndexedMemProfRecord to MemProfRecord.  Callback is used to
   // translate CallStackId to call stacks with frames inline.
   MemProfRecord toMemProfRecord(
-      llvm::function_ref<const llvm::SmallVector<Frame>(const CallStackId)>
-          Callback) const;
+      llvm::function_ref<llvm::SmallVector<Frame>(const CallStackId)> Callback)
+      const;
 
   // Returns the GUID for the function name after canonicalization. For
   // memprof, we remove any .llvm suffix added by LTO. MemProfRecords are
diff --git a/llvm/lib/ProfileData/MemProf.cpp b/llvm/lib/ProfileData/MemProf.cpp
index e5608644519db..89afe7c39027c 100644
--- a/llvm/lib/ProfileData/MemProf.cpp
+++ b/llvm/lib/ProfileData/MemProf.cpp
@@ -245,8 +245,8 @@ IndexedMemProfRecord::deserialize(const MemProfSchema &Schema,
 }
 
 MemProfRecord IndexedMemProfRecord::toMemProfRecord(
-    llvm::function_ref<const llvm::SmallVector<Frame>(const CallStackId)>
-        Callback) const {
+    llvm::function_ref<llvm::SmallVector<Frame>(const CallStackId)> Callback)
+    const {
   MemProfRecord Record;
 
   Record.AllocSites.reserve(AllocSites.size());