[Sema] Make BreakContinueFinder handle nested loops.

We don't care about break or continue statements that aren't
associated with the current loop, so make sure the visitor
doesn't find them.

Fixes https://bugs.llvm.org/show_bug.cgi?id=32648 .

Differential Revision: https://reviews.llvm.org/D34568

llvm-svn: 307051

1 files changed, 61 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index eed10b077eb..2a38a1f8e1d 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -1544,23 +1544,78 @@ namespace {
 
   // A visitor to determine if a continue or break statement is a
   // subexpression.
-  class BreakContinueFinder : public EvaluatedExprVisitor<BreakContinueFinder> {
+  class BreakContinueFinder : public ConstEvaluatedExprVisitor<BreakContinueFinder> {
     SourceLocation BreakLoc;
     SourceLocation ContinueLoc;
+    bool InSwitch = false;
+
   public:
-    BreakContinueFinder(Sema &S, Stmt* Body) :
+    BreakContinueFinder(Sema &S, const Stmt* Body) :
         Inherited(S.Context) {
       Visit(Body);
     }
 
-    typedef EvaluatedExprVisitor<BreakContinueFinder> Inherited;
+    typedef ConstEvaluatedExprVisitor<BreakContinueFinder> Inherited;
 
-    void VisitContinueStmt(ContinueStmt* E) {
+    void VisitContinueStmt(const ContinueStmt* E) {
       ContinueLoc = E->getContinueLoc();
     }
 
-    void VisitBreakStmt(BreakStmt* E) {
-      BreakLoc = E->getBreakLoc();
+    void VisitBreakStmt(const BreakStmt* E) {
+      if (!InSwitch)
+        BreakLoc = E->getBreakLoc();
+    }
+
+    void VisitSwitchStmt(const SwitchStmt* S) {
+      if (const Stmt *Init = S->getInit())
+        Visit(Init);
+      if (const Stmt *CondVar = S->getConditionVariableDeclStmt())
+        Visit(CondVar);
+      if (const Stmt *Cond = S->getCond())
+        Visit(Cond);
+
+      // Don't return break statements from the body of a switch.
+      InSwitch = true;
+      if (const Stmt *Body = S->getBody())
+        Visit(Body);
+      InSwitch = false;
+    }
+
+    void VisitForStmt(const ForStmt *S) {
+      // Only visit the init statement of a for loop; the body
+      // has a different break/continue scope.
+      if (const Stmt *Init = S->getInit())
+        Visit(Init);
+    }
+
+    void VisitWhileStmt(const WhileStmt *) {
+      // Do nothing; the children of a while loop have a different
+      // break/continue scope.
+    }
+
+    void VisitDoStmt(const DoStmt *) {
+      // Do nothing; the children of a while loop have a different
+      // break/continue scope.
+    }
+
+    void VisitCXXForRangeStmt(const CXXForRangeStmt *S) {
+      // Only visit the initialization of a for loop; the body
+      // has a different break/continue scope.
+      if (const Stmt *Range = S->getRangeStmt())
+        Visit(Range);
+      if (const Stmt *Begin = S->getBeginStmt())
+        Visit(Begin);
+      if (const Stmt *End = S->getEndStmt())
+        Visit(End);
+    }
+
+    void VisitObjCForCollectionStmt(const ObjCForCollectionStmt *S) {
+      // Only visit the initialization of a for loop; the body
+      // has a different break/continue scope.
+      if (const Stmt *Element = S->getElement())
+        Visit(Element);
+      if (const Stmt *Collection = S->getCollection())
+        Visit(Collection);
     }
 
     bool ContinueFound() { return ContinueLoc.isValid(); }