make the dataflow algorithm generic to avoid duplication

Author: usx95

clang/lib/Analysis/LifetimeSafety.cpp

@@ -737,7 +737,7 @@ class LifetimeDataflow {
 struct ExpiredLattice {
   LoanSet Expired;
 
-  ExpiredLattice() = default;
+  ExpiredLattice() : Expired(nullptr) {};
   explicit ExpiredLattice(LoanSet S) : Expired(S) {}
 
   bool operator==(const ExpiredLattice &Other) const {
@@ -814,10 +814,10 @@ class ExpiredLoansAnalysis {
       : Cfg(C), AC(AC), Xfer(FS, SetFactory) {}
 
   void run() {
-    llvm::TimeTraceScope TimeProfile("Expired Loans Analysis");
+    llvm::TimeTraceScope TimeProfile("ExpiredLoansAnalysis");
     ForwardDataflowWorklist Worklist(Cfg, AC);
     const CFGBlock *Entry = &Cfg.getEntry();
-    BlockEntryStates[Entry] = ExpiredLattice(SetFactory.getEmptySet());
+    BlockEntryStates[Entry] = ExpiredLattice{};
     Worklist.enqueueBlock(Entry);
     while (const CFGBlock *B = Worklist.dequeue()) {
       ExpiredLattice EntryState = getEntryState(B);
@@ -849,24 +849,16 @@ class ExpiredLoansAnalysis {
   }
 
   ExpiredLattice getEntryState(const CFGBlock *B) const {
-    auto It = BlockEntryStates.find(B);
-    if (It != BlockEntryStates.end()) {
-      return It->second;
-    }
-    return ExpiredLattice(SetFactory.getEmptySet());
+    return BlockEntryStates.lookup(B);
   }
 
   ExpiredLattice getExitState(const CFGBlock *B) const {
-    auto It = BlockExitStates.find(B);
-    if (It != BlockExitStates.end()) {
-      return It->second;
-    }
-    return ExpiredLattice(SetFactory.getEmptySet());
+    return BlockExitStates.lookup(B);
   }
 };
 
 // ========================================================================= //
-//  TODO: Analysing dataflow results and error reporting.
+//  TODO: Liveness analysis, analysing dataflow results and error reporting.
 // ========================================================================= //
 } // anonymous namespace
 
@@ -895,6 +887,6 @@ void runLifetimeSafetyAnalysis(const DeclContext &DC, const CFG &Cfg,
 
   ExpiredLoansAnalysis ExpiredAnalysis(Cfg, FactMgr, AC);
   ExpiredAnalysis.run();
-  DEBUG_WITH_TYPE("ExpiredLoans", ExpiredAnalysis.dump());
+  DEBUG_WITH_TYPE("LifetimeExpiredLoans", ExpiredAnalysis.dump());
 }
 } // namespace clang