Provide an invalidate method in ProfileSummaryInfo that returns false

[eraman]

Missed adding llvm-commits as a subscriber when I created this. I added soon after, but I suspect phabricator doesn't send an email then. Hopefully this commit triggers an email.

[chandlerc]

LGTM

llvm/trunk/include/llvm/Analysis/ProfileSummaryInfo.h

private:
   void computeThresholds();
   // Count thresholds to answer isHotCount and isColdCount queries.
   Optional<uint64_t> HotCountThreshold, ColdCountThreshold;
 
 public:
   ProfileSummaryInfo(Module &M) : M(M) {}
   ProfileSummaryInfo(ProfileSummaryInfo &&Arg)
       : M(Arg.M), Summary(std::move(Arg.Summary)) {}
+
+  /// Handle the invalidation of this information.
+  ///
+  /// When used as a result of \c ProfileSummaryAnalysis this method will be
+  /// called when the module this was computed for changes. Since profile
+  /// summary is immutable after it is annotated on the module, we return false
+  /// here.
+  bool invalidate(Module &, const PreservedAnalyses &,
+                  ModuleAnalysisManager::Invalidator &) {
+    return false;
+  }
+
   /// Returns the profile count for \p CallInst.
   static Optional<uint64_t> getProfileCount(const Instruction *CallInst,
                                             BlockFrequencyInfo *BFI);
   /// \brief Returns true if \p F has hot function entry.
   bool isFunctionEntryHot(const Function *F);
   /// Returns true if \p F has hot function entry or hot call edge.
   bool isFunctionHotInCallGraph(const Function *F);
   /// \brief Returns true if \p F has cold function entry.