[MBFI] Move BranchFolding::MBFIWrapper to its own files. NFC.

Summary:
To avoid header file circular dependency issues in passing updated MBFI (in
MBFIWrapper) to the interface of profile guided size optimizations.

A prep step for (and split off of) D73381.

Reviewers: davidxl

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73494
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index a38c4f3..eb4e076 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -129,7 +129,7 @@
   // HW that requires structurized CFG.
   bool EnableTailMerge = !MF.getTarget().requiresStructuredCFG() &&
                          PassConfig->getEnableTailMerge();
-  BranchFolder::MBFIWrapper MBBFreqInfo(
+  MBFIWrapper MBBFreqInfo(
       getAnalysis<MachineBlockFrequencyInfo>());
   BranchFolder Folder(EnableTailMerge, /*CommonHoist=*/true, MBBFreqInfo,
                       getAnalysis<MachineBranchProbabilityInfo>(),
@@ -501,42 +501,6 @@
 #endif
 }
 
-BlockFrequency
-BranchFolder::MBFIWrapper::getBlockFreq(const MachineBasicBlock *MBB) const {
-  auto I = MergedBBFreq.find(MBB);
-
-  if (I != MergedBBFreq.end())
-    return I->second;
-
-  return MBFI.getBlockFreq(MBB);
-}
-
-void BranchFolder::MBFIWrapper::setBlockFreq(const MachineBasicBlock *MBB,
-                                             BlockFrequency F) {
-  MergedBBFreq[MBB] = F;
-}
-
-raw_ostream &
-BranchFolder::MBFIWrapper::printBlockFreq(raw_ostream &OS,
-                                          const MachineBasicBlock *MBB) const {
-  return MBFI.printBlockFreq(OS, getBlockFreq(MBB));
-}
-
-raw_ostream &
-BranchFolder::MBFIWrapper::printBlockFreq(raw_ostream &OS,
-                                          const BlockFrequency Freq) const {
-  return MBFI.printBlockFreq(OS, Freq);
-}
-
-void BranchFolder::MBFIWrapper::view(const Twine &Name, bool isSimple) {
-  MBFI.view(Name, isSimple);
-}
-
-uint64_t
-BranchFolder::MBFIWrapper::getEntryFreq() const {
-  return MBFI.getEntryFreq();
-}
-
 /// CountTerminators - Count the number of terminators in the given
 /// block and set I to the position of the first non-terminator, if there
 /// is one, or MBB->end() otherwise.
@@ -591,7 +555,7 @@
                   MachineBasicBlock *PredBB,
                   DenseMap<const MachineBasicBlock *, int> &EHScopeMembership,
                   bool AfterPlacement,
-                  BranchFolder::MBFIWrapper &MBBFreqInfo,
+                  MBFIWrapper &MBBFreqInfo,
                   ProfileSummaryInfo *PSI) {
   // It is never profitable to tail-merge blocks from two different EH scopes.
   if (!EHScopeMembership.empty()) {