refactor BlockFrequencyInfo::view to take a title parameter

[david2050]

Summary

All a non-default title for the debugging this debugging aide

[twoh]

LGTM

llvm/trunk/include/llvm/Analysis/BlockFrequencyInfo.h

public:
   ~BlockFrequencyInfo();
 
   /// Handle invalidation explicitly.
   bool invalidate(Function &F, const PreservedAnalyses &PA,
                   FunctionAnalysisManager::Invalidator &);
 
   const Function *getFunction() const;
   const BranchProbabilityInfo *getBPI() const;
-  void view() const;
+  void view(StringRef = "BlockFrequencyDAGs") const;
 
   /// getblockFreq - Return block frequency. Return 0 if we don't have the
   /// information. Please note that initial frequency is equal to ENTRY_FREQ. It
   /// means that we should not rely on the value itself, but only on the
   /// comparison to the other block frequencies. We do this to avoid using of
   /// floating points.
   BlockFrequency getBlockFreq(const BasicBlock *BB) const;
 

llvm/trunk/lib/Analysis/BlockFrequencyInfo.cpp

for (auto *BB : BlocksToScale) {
     BBFreq = BBFreq.udiv(OldFreq);
     BFI->setBlockFreq(BB, BBFreq.getLimitedValue());
   }
   BFI->setBlockFreq(ReferenceBB, Freq);
 }
 
 /// Pop up a ghostview window with the current block frequency propagation
 /// rendered using dot.
-void BlockFrequencyInfo::view() const {
-  ViewGraph(const_cast<BlockFrequencyInfo *>(this), "BlockFrequencyDAGs");
+void BlockFrequencyInfo::view(StringRef title) const {
+  ViewGraph(const_cast<BlockFrequencyInfo *>(this), title);
 }
 
 const Function *BlockFrequencyInfo::getFunction() const {
   return BFI ? BFI->getFunction() : nullptr;
 }
 
 const BranchProbabilityInfo *BlockFrequencyInfo::getBPI() const {
   return BFI ? &BFI->getBPI() : nullptr;