[CFG] NFC: Remove implicit conversion from CFGTerminator to Stmt *.

Turn it into a variant class instead. This conversion does indeed save some code
but there's a plan to add support for more kinds of terminators that aren't
necessarily based on statements, and with those in mind it becomes more and more
confusing to have CFGTerminators implicitly convertible to a Stmt *.

Differential Revision: https://reviews.llvm.org/D61814

llvm-svn: 361586

8 files changed, 36 insertions, 28 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index 0928fa27866..915e5cc222f 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -1956,7 +1956,7 @@ void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk,
     = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C);
   for (LocalScope::const_iterator I = B; I != E; ++I)
     InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I,
-                                            Blk->getTerminator());
+                                            Blk->getTerminatorStmt());
 }
 
 /// prependAutomaticObjLifetimeWithTerminator - Prepend lifetime CFGElements for
@@ -1971,8 +1971,10 @@ void CFGBuilder::prependAutomaticObjLifetimeWithTerminator(
   BumpVectorContext &C = cfg->getBumpVectorContext();
   CFGBlock::iterator InsertPos =
       Blk->beginLifetimeEndsInsert(Blk->end(), B.distance(E), C);
-  for (LocalScope::const_iterator I = B; I != E; ++I)
-    InsertPos = Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminator());
+  for (LocalScope::const_iterator I = B; I != E; ++I) {
+    InsertPos =
+        Blk->insertLifetimeEnds(InsertPos, *I, Blk->getTerminatorStmt());
+  }
 }
 
 /// prependAutomaticObjScopeEndWithTerminator - Prepend scope end CFGElements for
@@ -1991,7 +1993,7 @@ CFGBuilder::prependAutomaticObjScopeEndWithTerminator(
   LocalScope::const_iterator PlaceToInsert = B;
   for (LocalScope::const_iterator I = B; I != E; ++I)
     PlaceToInsert = I;
-  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminator());
+  Blk->insertScopeEnd(InsertPos, *PlaceToInsert, Blk->getTerminatorStmt());
   return *PlaceToInsert;
 }
 
@@ -4612,7 +4614,8 @@ void CFGBuilder::InsertTempDtorDecisionBlock(const TempDtorContext &Context,
   }
   assert(Context.TerminatorExpr);
   CFGBlock *Decision = createBlock(false);
-  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr, true));
+  Decision->setTerminator(CFGTerminator(Context.TerminatorExpr,
+                                        CFGTerminator::TemporaryDtorsBranch));
   addSuccessor(Decision, Block, !Context.KnownExecuted.isFalse());
   addSuccessor(Decision, FalseSucc ? FalseSucc : Context.Succ,
                !Context.KnownExecuted.isTrue());
@@ -4820,7 +4823,7 @@ bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F,
     // If the 'To' has no label or is labeled but the label isn't a
     // CaseStmt then filter this edge.
     if (const SwitchStmt *S =
-        dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) {
+        dyn_cast_or_null<SwitchStmt>(From->getTerminatorStmt())) {
       if (S->isAllEnumCasesCovered()) {
         const Stmt *L = To->getLabel();
         if (!L || !isa<CaseStmt>(L))
@@ -5055,9 +5058,15 @@ public:
 
 public:
   void print(CFGTerminator T) {
-    if (T.isTemporaryDtorsBranch())
+    switch (T.getKind()) {
+    case CFGTerminator::StmtBranch:
+      Visit(T.getStmt());
+      break;
+    case CFGTerminator::TemporaryDtorsBranch:
       OS << "(Temp Dtor) ";
-    Visit(T.getStmt());
+      Visit(T.getStmt());
+      break;
+    }
   }
 };
 
@@ -5366,7 +5375,7 @@ static void print_block(raw_ostream &OS, const CFG* cfg,
   }
 
   // Print the terminator of this block.
-  if (B.getTerminator()) {
+  if (B.getTerminator().isValid()) {
     if (ShowColors)
       OS.changeColor(raw_ostream::GREEN);
 
@@ -5519,7 +5528,7 @@ void CFGBlock::printTerminator(raw_ostream &OS,
 }
 
 Stmt *CFGBlock::getTerminatorCondition(bool StripParens) {
-  Stmt *Terminator = this->Terminator;
+  Stmt *Terminator = getTerminatorStmt();
   if (!Terminator)
     return nullptr;
 
diff --git a/clang/lib/Analysis/CFGStmtMap.cpp b/clang/lib/Analysis/CFGStmtMap.cpp
index eab2fafb546..d1c23e3c879 100644
--- a/clang/lib/Analysis/CFGStmtMap.cpp
+++ b/clang/lib/Analysis/CFGStmtMap.cpp
@@ -70,7 +70,7 @@ static void Accumulate(SMap &SM, CFGBlock *B) {
   // Finally, look at the terminator.  If the terminator was already added
   // because it is a block-level expression in another block, overwrite
   // that mapping.
-  if (Stmt *Term = B->getTerminator())
+  if (Stmt *Term = B->getTerminatorStmt())
     SM[Term] = B;
 }
 
diff --git a/clang/lib/Analysis/Consumed.cpp b/clang/lib/Analysis/Consumed.cpp
index 112ef5f91f3..eee36d9caf7 100644
--- a/clang/lib/Analysis/Consumed.cpp
+++ b/clang/lib/Analysis/Consumed.cpp
@@ -76,7 +76,7 @@ static SourceLocation getFirstStmtLoc(const CFGBlock *Block) {
 static SourceLocation getLastStmtLoc(const CFGBlock *Block) {
   // Find the source location of the last statement in the block, if the block
   // is not empty.
-  if (const Stmt *StmtNode = Block->getTerminator()) {
+  if (const Stmt *StmtNode = Block->getTerminatorStmt()) {
     return StmtNode->getBeginLoc();
   } else {
     for (CFGBlock::const_reverse_iterator BI = Block->rbegin(),
diff --git a/clang/lib/Analysis/LiveVariables.cpp b/clang/lib/Analysis/LiveVariables.cpp
index e435ff2ee17..2cd607d8a49 100644
--- a/clang/lib/Analysis/LiveVariables.cpp
+++ b/clang/lib/Analysis/LiveVariables.cpp
@@ -501,7 +501,7 @@ LiveVariablesImpl::runOnBlock(const CFGBlock *block,
   TransferFunctions TF(*this, val, obs, block);
 
   // Visit the terminator (if any).
-  if (const Stmt *term = block->getTerminator())
+  if (const Stmt *term = block->getTerminatorStmt())
     TF.Visit(const_cast<Stmt*>(term));
 
   // Apply the transfer function for all Stmts in the block.
diff --git a/clang/lib/Analysis/ProgramPoint.cpp b/clang/lib/Analysis/ProgramPoint.cpp
index 828388716ea..697d2e57ced 100644
--- a/clang/lib/Analysis/ProgramPoint.cpp
+++ b/clang/lib/Analysis/ProgramPoint.cpp
@@ -144,7 +144,7 @@ void ProgramPoint::print(StringRef CR, llvm::raw_ostream &Out) const {
     Out << "Edge: (B" << E.getSrc()->getBlockID() << ", B"
         << E.getDst()->getBlockID() << ')';
 
-    if (const Stmt *T = E.getSrc()->getTerminator()) {
+    if (const Stmt *T = E.getSrc()->getTerminatorStmt()) {
       SourceLocation SLoc = T->getBeginLoc();
 
       Out << "\\|Terminator: ";
diff --git a/clang/lib/Analysis/ReachableCode.cpp b/clang/lib/Analysis/ReachableCode.cpp
index f3bc0c7d8a5..2fea88ea2ef 100644
--- a/clang/lib/Analysis/ReachableCode.cpp
+++ b/clang/lib/Analysis/ReachableCode.cpp
@@ -48,7 +48,7 @@ static bool isTrivialExpression(const Expr *Ex) {
 static bool isTrivialDoWhile(const CFGBlock *B, const Stmt *S) {
   // Check if the block ends with a do...while() and see if 'S' is the
   // condition.
-  if (const Stmt *Term = B->getTerminator()) {
+  if (const Stmt *Term = B->getTerminatorStmt()) {
     if (const DoStmt *DS = dyn_cast<DoStmt>(Term)) {
       const Expr *Cond = DS->getCond()->IgnoreParenCasts();
       return Cond == S && isTrivialExpression(Cond);
@@ -116,7 +116,7 @@ static bool isDeadReturn(const CFGBlock *B, const Stmt *S) {
       // the call to the destructor.
       assert(Current->succ_size() == 2);
       Current = *(Current->succ_begin() + 1);
-    } else if (!Current->getTerminator() && Current->succ_size() == 1) {
+    } else if (!Current->getTerminatorStmt() && Current->succ_size() == 1) {
       // If there is only one successor, we're not dealing with outgoing control
       // flow. Thus, look into the next block.
       Current = *Current->succ_begin();
@@ -292,7 +292,7 @@ static bool isConfigurationValue(const ValueDecl *D, Preprocessor &PP) {
 /// Returns true if we should always explore all successors of a block.
 static bool shouldTreatSuccessorsAsReachable(const CFGBlock *B,
                                              Preprocessor &PP) {
-  if (const Stmt *Term = B->getTerminator()) {
+  if (const Stmt *Term = B->getTerminatorStmt()) {
     if (isa<SwitchStmt>(Term))
       return true;
     // Specially handle '||' and '&&'.
@@ -461,12 +461,11 @@ const Stmt *DeadCodeScan::findDeadCode(const clang::CFGBlock *Block) {
         return S;
     }
 
-  if (CFGTerminator T = Block->getTerminator()) {
-    if (!T.isTemporaryDtorsBranch()) {
-      const Stmt *S = T.getStmt();
-      if (isValidDeadStmt(S))
-        return S;
-    }
+  CFGTerminator T = Block->getTerminator();
+  if (T.isStmtBranch()) {
+    const Stmt *S = T.getStmt();
+    if (S && isValidDeadStmt(S))
+      return S;
   }
 
   return nullptr;
diff --git a/clang/lib/Analysis/ThreadSafety.cpp b/clang/lib/Analysis/ThreadSafety.cpp
index bd65ea711b9..c7b4c445566 100644
--- a/clang/lib/Analysis/ThreadSafety.cpp
+++ b/clang/lib/Analysis/ThreadSafety.cpp
@@ -815,7 +815,7 @@ static void findBlockLocations(CFG *CFGraph,
 
     // Find the source location of the last statement in the block, if the
     // block is not empty.
-    if (const Stmt *S = CurrBlock->getTerminator()) {
+    if (const Stmt *S = CurrBlock->getTerminatorStmt()) {
       CurrBlockInfo->EntryLoc = CurrBlockInfo->ExitLoc = S->getBeginLoc();
     } else {
       for (CFGBlock::const_reverse_iterator BI = CurrBlock->rbegin(),
@@ -1499,7 +1499,7 @@ void ThreadSafetyAnalyzer::getEdgeLockset(FactSet& Result,
 
   const Stmt *Cond = PredBlock->getTerminatorCondition();
   // We don't acquire try-locks on ?: branches, only when its result is used.
-  if (!Cond || isa<ConditionalOperator>(PredBlock->getTerminator()))
+  if (!Cond || isa<ConditionalOperator>(PredBlock->getTerminatorStmt()))
     return;
 
   bool Negate = false;
@@ -2402,7 +2402,7 @@ void ThreadSafetyAnalyzer::runAnalysis(AnalysisDeclContext &AC) {
       // a difference in locksets is probably due to a bug in that block, rather
       // than in some other predecessor. In that case, keep the other
       // predecessor's lockset.
-      if (const Stmt *Terminator = (*PI)->getTerminator()) {
+      if (const Stmt *Terminator = (*PI)->getTerminatorStmt()) {
         if (isa<ContinueStmt>(Terminator) || isa<BreakStmt>(Terminator)) {
           SpecialBlocks.push_back(*PI);
           continue;
@@ -2441,7 +2441,7 @@ void ThreadSafetyAnalyzer::runAnalysis(AnalysisDeclContext &AC) {
         // it might also be part of a switch. Also, a subsequent destructor
         // might add to the lockset, in which case the real issue might be a
         // double lock on the other path.
-        const Stmt *Terminator = PrevBlock->getTerminator();
+        const Stmt *Terminator = PrevBlock->getTerminatorStmt();
         bool IsLoop = Terminator && isa<ContinueStmt>(Terminator);
 
         FactSet PrevLockset;
diff --git a/clang/lib/Analysis/UninitializedValues.cpp b/clang/lib/Analysis/UninitializedValues.cpp
index 96f4cc51b7a..cea401ab5c3 100644
--- a/clang/lib/Analysis/UninitializedValues.cpp
+++ b/clang/lib/Analysis/UninitializedValues.cpp
@@ -651,7 +651,7 @@ public:
     // uninitialized.
     for (const auto *Block : cfg) {
       unsigned BlockID = Block->getBlockID();
-      const Stmt *Term = Block->getTerminator();
+      const Stmt *Term = Block->getTerminatorStmt();
       if (SuccsVisited[BlockID] && SuccsVisited[BlockID] < Block->succ_size() &&
           Term) {
         // This block inevitably leads to the use. If we have an edge from here