Use unique_ptr in BlockFrequencyAnalysis

[dblaikie]

Generally looks good. A couple of optional comments (feel free to commit with or without those changes, without further review)

lib/Analysis/InlineCost.cpp

1580

Use "= default" perhaps? (no big reason, if you particularly prefer "{}", that's OK)

1585–1595

This function does an extra map lookup (2, could use 1 - assuming that the code to build the BFI doesn't cause other BFIs to be constructed (invalidating access to the entry in the map))

& I'd consider rewriting it as something like:

auto &BFI = BFM[F]
if (!BFI) {
  DominatorTree DT;
  DT.recalculate(*F);
  LoopInfo LI(DT);
  BranchProbabilityInfo BPI(*F, LI);
  BFI = llvm::make_unique<BlockFrequencyInfo>(*F, BPI, LI);
}
return BFI.get();

include/llvm/Analysis/InlineCost.h

namespace InlineConstants {
   const unsigned TotalAllocaSizeRecursiveCaller = 1024;
 }
 
 /// \brief Block frequency analysis for multiple functions.
 /// This class mimics block frequency analysis on CGSCC level. Block frequency
 /// info is computed on demand and cached unless they are invalidated.
 class BlockFrequencyAnalysis {
 private:
-  DenseMap<Function *, BlockFrequencyInfo *> BFM;
+  DenseMap<Function *, std::unique_ptr<BlockFrequencyInfo>> BFM;
 
 public:
+  // Make the constructor and destructor out-of-line to avoid including
+  // BlockFrerquencyInfo.h
+  BlockFrequencyAnalysis();
   ~BlockFrequencyAnalysis();
   /// \brief Returns BlockFrequencyInfo for a function.
   BlockFrequencyInfo *getBlockFrequencyInfo(Function *);
   /// \brief Invalidates block frequency info for a function.
   void invalidateBlockFrequencyInfo(Function *);
 };
 
 /// \brief Represents the cost of inlining a function.

lib/Analysis/InlineCost.cpp

if (!EntryCount)
     return None;
   BlockFrequencyInfo *BFI = BFA->getBlockFrequencyInfo(F);
   uint64_t BBFreq = BFI->getBlockFreq(BB).getFrequency();
   uint64_t FunctionEntryFreq = BFI->getEntryFreq();
   uint64_t BBCount = EntryCount.getValue() * BBFreq / FunctionEntryFreq;
   return BBCount;
 }
 
-BlockFrequencyAnalysis::~BlockFrequencyAnalysis() {
-  for (auto &Entry : BFM) {
-    delete Entry.second;
-  }
-}
+BlockFrequencyAnalysis::BlockFrequencyAnalysis() {}
+BlockFrequencyAnalysis::~BlockFrequencyAnalysis() {}
 
 /// \brief Get BlockFrequencyInfo for a function.
 BlockFrequencyInfo *BlockFrequencyAnalysis::getBlockFrequencyInfo(Function *F) {
   auto Iter = BFM.find(F);
   if (Iter != BFM.end())
-    return Iter->second;
+    return Iter->second.get();
   // We need to create a BlockFrequencyInfo object for F and store it.
   DominatorTree DT;
   DT.recalculate(*F);
   LoopInfo LI(DT);
   BranchProbabilityInfo BPI(*F, LI);
   BlockFrequencyInfo *BFI = new BlockFrequencyInfo(*F, BPI, LI);
-  BFM[F] = BFI;
+  BFM[F].reset(BFI);
   return BFI;
 }
 
 /// \brief Invalidate BlockFrequencyInfo for a function.
 void BlockFrequencyAnalysis::invalidateBlockFrequencyInfo(Function *F) {
-  if (BFM.count(F)) {
-    delete BFM[F];
-    BFM.erase(F);
-  }
-}