[llvm] [MemProf] Constify a couple of methods used during cloning (PR #124994)

[Teresa Johnson via llvm-commits]

https://github.com/teresajohnson created https://github.com/llvm/llvm-project/pull/124994

This also helps ensure we don't inadvartently create map entries
by forcing use of at() instead of operator[].


>From 1908755e8e196eb8a873a6ed2c7268e4ecd65d10 Mon Sep 17 00:00:00 2001
From: Teresa Johnson <tejohnson at google.com>
Date: Wed, 29 Jan 2025 13:54:40 -0800
Subject: [PATCH] [MemProf] Constify a couple of methods used during cloning

This also helps ensure we don't inadvartently create map entries
by forcing use of at() instead of operator[].
---
 .../IPO/MemProfContextDisambiguation.cpp       | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp b/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
index 03e2e7089202ded..d83beae4d643333 100644
--- a/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
+++ b/llvm/lib/Transforms/IPO/MemProfContextDisambiguation.cpp
@@ -677,18 +677,18 @@ class CallsiteContextGraph {
 
   /// Computes the alloc type corresponding to the given context ids, by
   /// unioning their recorded alloc types.
-  uint8_t computeAllocType(DenseSet<uint32_t> &ContextIds);
+  uint8_t computeAllocType(DenseSet<uint32_t> &ContextIds) const;
 
   /// Returns the allocation type of the intersection of the contexts of two
   /// nodes (based on their provided context id sets), optimized for the case
   /// when Node1Ids is smaller than Node2Ids.
   uint8_t intersectAllocTypesImpl(const DenseSet<uint32_t> &Node1Ids,
-                                  const DenseSet<uint32_t> &Node2Ids);
+                                  const DenseSet<uint32_t> &Node2Ids) const;
 
   /// Returns the allocation type of the intersection of the contexts of two
   /// nodes (based on their provided context id sets).
   uint8_t intersectAllocTypes(const DenseSet<uint32_t> &Node1Ids,
-                              const DenseSet<uint32_t> &Node2Ids);
+                              const DenseSet<uint32_t> &Node2Ids) const;
 
   /// Create a clone of Edge's callee and move Edge to that new callee node,
   /// performing the necessary context id and allocation type updates.
@@ -1152,12 +1152,12 @@ void CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::ContextNode::
 
 template <typename DerivedCCG, typename FuncTy, typename CallTy>
 uint8_t CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::computeAllocType(
-    DenseSet<uint32_t> &ContextIds) {
+    DenseSet<uint32_t> &ContextIds) const {
   uint8_t BothTypes =
       (uint8_t)AllocationType::Cold | (uint8_t)AllocationType::NotCold;
   uint8_t AllocType = (uint8_t)AllocationType::None;
   for (auto Id : ContextIds) {
-    AllocType |= (uint8_t)ContextIdToAllocationType[Id];
+    AllocType |= (uint8_t)ContextIdToAllocationType.at(Id);
     // Bail early if alloc type reached both, no further refinement.
     if (AllocType == BothTypes)
       return AllocType;
@@ -1168,14 +1168,15 @@ uint8_t CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::computeAllocType(
 template <typename DerivedCCG, typename FuncTy, typename CallTy>
 uint8_t
 CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::intersectAllocTypesImpl(
-    const DenseSet<uint32_t> &Node1Ids, const DenseSet<uint32_t> &Node2Ids) {
+    const DenseSet<uint32_t> &Node1Ids,
+    const DenseSet<uint32_t> &Node2Ids) const {
   uint8_t BothTypes =
       (uint8_t)AllocationType::Cold | (uint8_t)AllocationType::NotCold;
   uint8_t AllocType = (uint8_t)AllocationType::None;
   for (auto Id : Node1Ids) {
     if (!Node2Ids.count(Id))
       continue;
-    AllocType |= (uint8_t)ContextIdToAllocationType[Id];
+    AllocType |= (uint8_t)ContextIdToAllocationType.at(Id);
     // Bail early if alloc type reached both, no further refinement.
     if (AllocType == BothTypes)
       return AllocType;
@@ -1185,7 +1186,8 @@ CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::intersectAllocTypesImpl(
 
 template <typename DerivedCCG, typename FuncTy, typename CallTy>
 uint8_t CallsiteContextGraph<DerivedCCG, FuncTy, CallTy>::intersectAllocTypes(
-    const DenseSet<uint32_t> &Node1Ids, const DenseSet<uint32_t> &Node2Ids) {
+    const DenseSet<uint32_t> &Node1Ids,
+    const DenseSet<uint32_t> &Node2Ids) const {
   if (Node1Ids.size() < Node2Ids.size())
     return intersectAllocTypesImpl(Node1Ids, Node2Ids);
   else