fix PR6034, a crash on invalid where the switch stack would get

unbalanced.

llvm-svn: 94347

clang/include/clang/Parse/Action.h

@@ -808,6 +808,11 @@ public:
     return StmtEmpty();
   }
 
+  /// ActOnSwitchBodyError - This is called if there is an error parsing the
+  /// body of the switch stmt instead of ActOnFinishSwitchStmt.
+  virtual void ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch,
+                                    StmtArg Body) {}
+  
   virtual OwningStmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                                  StmtArg Switch, StmtArg Body) {
     return StmtEmpty();

clang/lib/Parse/ParseStmt.cpp

@@ -741,19 +741,19 @@ Parser::OwningStmtResult Parser::ParseSwitchStatement(AttributeList *Attr) {
   // Read the body statement.
   OwningStmtResult Body(ParseStatement());
 
-  // Pop the body scope if needed.
+  // Pop the scopes.
   InnerScope.Exit();
-
-  if (Body.isInvalid()) {
-    Body = Actions.ActOnNullStmt(Tok.getLocation());
-    // FIXME: Remove the case statement list from the Switch statement.
-  }
-
   SwitchScope.Exit();
 
-  if (Cond.isInvalid() && !CondVar.get())
+  if (Cond.isInvalid() && !CondVar.get()) {
+    Actions.ActOnSwitchBodyError(SwitchLoc, move(Switch), move(Body));
     return StmtError();
+  }
 
+  if (Body.isInvalid())
+    // FIXME: Remove the case statement list from the Switch statement.
+    Body = Actions.ActOnNullStmt(Tok.getLocation());
+  
   return Actions.ActOnFinishSwitchStmt(SwitchLoc, move(Switch), move(Body));
 }
 

clang/lib/Sema/Sema.h

@@ -1373,6 +1373,8 @@ public:
                                        SourceLocation ElseLoc, StmtArg ElseVal);
   virtual OwningStmtResult ActOnStartOfSwitchStmt(FullExprArg Cond, 
                                                   DeclPtrTy CondVar);
+  virtual void ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch,
+                                    StmtArg Body);
   virtual OwningStmtResult ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
                                                  StmtArg Switch, StmtArg Body);
   virtual OwningStmtResult ActOnWhileStmt(SourceLocation WhileLoc,

clang/lib/Sema/SemaStmt.cpp

@@ -482,6 +482,16 @@ static bool CheckCXXSwitchCondition(Sema &S, SourceLocation SwitchLoc,
   return false;
 }
 
+/// ActOnSwitchBodyError - This is called if there is an error parsing the
+/// body of the switch stmt instead of ActOnFinishSwitchStmt.
+void Sema::ActOnSwitchBodyError(SourceLocation SwitchLoc, StmtArg Switch,
+                                StmtArg Body) {
+  // Keep the switch stack balanced.
+  assert(getSwitchStack().back() == (SwitchStmt*)Switch.get() &&
+         "switch stack missing push/pop!");
+  getSwitchStack().pop_back();
+}
+
 Action::OwningStmtResult
 Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, StmtArg Switch,
                             StmtArg Body) {

clang/test/Sema/statements.c

@@ -33,3 +33,11 @@ void *test10() {
 bar:
   return &&bar;  // expected-warning {{returning address of label, which is local}}
 }
+
+// PR6034
+void test11(int bit) {
+  switch (bit)
+  switch (env->fpscr)  // expected-error {{use of undeclared identifier 'env'}}
+  {
+  }
+}