diff --git a/llvm/include/llvm/Transforms/IPO/HotColdSplitting.h b/llvm/include/llvm/Transforms/IPO/HotColdSplitting.h
--- a/llvm/include/llvm/Transforms/IPO/HotColdSplitting.h
+++ b/llvm/include/llvm/Transforms/IPO/HotColdSplitting.h
@@ -17,6 +17,42 @@
 namespace llvm {
 
 class Module;
+class ProfileSummaryInfo;
+class BlockFrequencyInfo;
+class TargetTransformInfo;
+class OptimizationRemarkEmitter;
+class AssumptionCache;
+class DominatorTree;
+
+/// A sequence of basic blocks.
+///
+/// A 0-sized SmallVector is slightly cheaper to move than a std::vector.
+using BlockSequence = SmallVector<BasicBlock *, 0>;
+
+class HotColdSplitting {
+public:
+  HotColdSplitting(ProfileSummaryInfo *ProfSI,
+                   function_ref<BlockFrequencyInfo *(Function &)> GBFI,
+                   function_ref<TargetTransformInfo &(Function &)> GTTI,
+                   std::function<OptimizationRemarkEmitter &(Function &)> *GORE,
+                   function_ref<AssumptionCache *(Function &)> LAC)
+      : PSI(ProfSI), GetBFI(GBFI), GetTTI(GTTI), GetORE(GORE), LookupAC(LAC) {}
+  bool run(Module &M);
+
+private:
+  bool isFunctionCold(const Function &F) const;
+  bool shouldOutlineFrom(const Function &F) const;
+  bool outlineColdRegions(Function &F, bool HasProfileSummary);
+  Function *extractColdRegion(const BlockSequence &Region, DominatorTree &DT,
+                              BlockFrequencyInfo *BFI, TargetTransformInfo &TTI,
+                              OptimizationRemarkEmitter &ORE,
+                              AssumptionCache *AC, unsigned Count);
+  ProfileSummaryInfo *PSI;
+  function_ref<BlockFrequencyInfo *(Function &)> GetBFI;
+  function_ref<TargetTransformInfo &(Function &)> GetTTI;
+  std::function<OptimizationRemarkEmitter &(Function &)> *GetORE;
+  function_ref<AssumptionCache *(Function &)> LookupAC;
+};
 
 /// Pass to outline cold regions.
 class HotColdSplittingPass : public PassInfoMixin<HotColdSplittingPass> {
diff --git a/llvm/lib/Transforms/IPO/HotColdSplitting.cpp b/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
--- a/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
+++ b/llvm/lib/Transforms/IPO/HotColdSplitting.cpp
@@ -85,12 +85,6 @@
                                 "multiple of TCC_Basic)"));
 
 namespace {
-
-/// A sequence of basic blocks.
-///
-/// A 0-sized SmallVector is slightly cheaper to move than a std::vector.
-using BlockSequence = SmallVector<BasicBlock *, 0>;
-
 // Same as blockEndsInUnreachable in CodeGen/BranchFolding.cpp. Do not modify
 // this function unless you modify the MBB version as well.
 //
@@ -169,31 +163,6 @@
   return Changed;
 }
 
-class HotColdSplitting {
-public:
-  HotColdSplitting(ProfileSummaryInfo *ProfSI,
-                   function_ref<BlockFrequencyInfo *(Function &)> GBFI,
-                   function_ref<TargetTransformInfo &(Function &)> GTTI,
-                   std::function<OptimizationRemarkEmitter &(Function &)> *GORE,
-                   function_ref<AssumptionCache *(Function &)> LAC)
-      : PSI(ProfSI), GetBFI(GBFI), GetTTI(GTTI), GetORE(GORE), LookupAC(LAC) {}
-  bool run(Module &M);
-
-private:
-  bool isFunctionCold(const Function &F) const;
-  bool shouldOutlineFrom(const Function &F) const;
-  bool outlineColdRegions(Function &F, bool HasProfileSummary);
-  Function *extractColdRegion(const BlockSequence &Region, DominatorTree &DT,
-                              BlockFrequencyInfo *BFI, TargetTransformInfo &TTI,
-                              OptimizationRemarkEmitter &ORE,
-                              AssumptionCache *AC, unsigned Count);
-  ProfileSummaryInfo *PSI;
-  function_ref<BlockFrequencyInfo *(Function &)> GetBFI;
-  function_ref<TargetTransformInfo &(Function &)> GetTTI;
-  std::function<OptimizationRemarkEmitter &(Function &)> *GetORE;
-  function_ref<AssumptionCache *(Function &)> LookupAC;
-};
-
 class HotColdSplittingLegacyPass : public ModulePass {
 public:
   static char ID;