Reject continue/break statements within members of local functions nested within

loop and switch statements, by teaching Scope that a function scope never has
a continue/break parent for the purposes of control flow. Remove the hack in
block and lambda expressions which worked around this by pretending that such
expressions were continue/break scopes.

Remove Scope::ControlParent, since it's unused.

In passing, teach default statements to recover properly from a missing ';', and
add a fixit for same to both default and case labels (the latter already
recovered correctly).

llvm-svn: 150776

4 files changed, 25 insertions, 16 deletions

diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 642fc2ac650..75510ad440a 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -2290,7 +2290,6 @@ ExprResult Parser::ParseBlockLiteralExpression() {
   // allows determining whether a variable reference inside the block is
   // within or outside of the block.
   ParseScope BlockScope(this, Scope::BlockScope | Scope::FnScope |
-                              Scope::BreakScope | Scope::ContinueScope |
                               Scope::DeclScope);
 
   // Inform sema that we are starting a block.
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index d09dba25856..76cc3928664 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -871,7 +871,6 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
   // FIXME: Rename BlockScope -> ClosureScope if we decide to continue using
   // it.
   ParseScope BodyScope(this, Scope::BlockScope | Scope::FnScope |
-                             Scope::BreakScope | Scope::ContinueScope |
                              Scope::DeclScope);
 
   Actions.ActOnStartOfLambdaDefinition(Intro, D, getCurScope());
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index 8af4da6a846..c256f7842de 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -596,7 +596,8 @@ StmtResult Parser::ParseCaseStatement(ParsedAttributes &attrs, bool MissingCase,
     // Nicely diagnose the common error "switch (X) { case 4: }", which is
     // not valid.
     SourceLocation AfterColonLoc = PP.getLocForEndOfToken(ColonLoc);
-    Diag(AfterColonLoc, diag::err_label_end_of_compound_statement);
+    Diag(AfterColonLoc, diag::err_label_end_of_compound_statement)
+      << FixItHint::CreateInsertion(AfterColonLoc, " ;");
     SubStmt = true;
   }
 
@@ -638,16 +639,22 @@ StmtResult Parser::ParseDefaultStatement(ParsedAttributes &attrs) {
     ColonLoc = ExpectedLoc;
   }
 
-  // Diagnose the common error "switch (X) {... default: }", which is not valid.
-  if (Tok.is(tok::r_brace)) {
+  StmtResult SubStmt;
+
+  if (Tok.isNot(tok::r_brace)) {
+    SubStmt = ParseStatement();
+  } else {
+    // Diagnose the common error "switch (X) {... default: }", which is
+    // not valid.
     SourceLocation AfterColonLoc = PP.getLocForEndOfToken(ColonLoc);
-    Diag(AfterColonLoc, diag::err_label_end_of_compound_statement);
-    return StmtError();
+    Diag(AfterColonLoc, diag::err_label_end_of_compound_statement)
+      << FixItHint::CreateInsertion(AfterColonLoc, " ;");
+    SubStmt = true;
   }
 
-  StmtResult SubStmt(ParseStatement());
+  // Broken sub-stmt shouldn't prevent forming the case statement properly.
   if (SubStmt.isInvalid())
-    return StmtError();
+    SubStmt = Actions.ActOnNullStmt(ColonLoc);
 
   return Actions.ActOnDefaultStmt(DefaultLoc, ColonLoc,
                                   SubStmt.get(), getCurScope());
diff --git a/clang/lib/Sema/Scope.cpp b/clang/lib/Sema/Scope.cpp
index 833a59fdcee..c76f61af6c7 100644
--- a/clang/lib/Sema/Scope.cpp
+++ b/clang/lib/Sema/Scope.cpp
@@ -19,23 +19,28 @@ using namespace clang;
 void Scope::Init(Scope *parent, unsigned flags) {
   AnyParent = parent;
   Flags = flags;
-    
+
+  if (parent && !(flags & FnScope)) {
+    BreakParent    = parent->BreakParent;
+    ContinueParent = parent->ContinueParent;
+  } else {
+    // Control scopes do not contain the contents of nested function scopes for
+    // control flow purposes.
+    BreakParent = ContinueParent = 0;
+  }
+
   if (parent) {
     Depth = parent->Depth + 1;
     PrototypeDepth = parent->PrototypeDepth;
     PrototypeIndex = 0;
     FnParent       = parent->FnParent;
-    BreakParent    = parent->BreakParent;
-    ContinueParent = parent->ContinueParent;
-    ControlParent  = parent->ControlParent;
     BlockParent    = parent->BlockParent;
     TemplateParamParent = parent->TemplateParamParent;
   } else {
     Depth = 0;
     PrototypeDepth = 0;
     PrototypeIndex = 0;
-    FnParent = BreakParent = ContinueParent = BlockParent = 0;
-    ControlParent = 0;
+    FnParent = BlockParent = 0;
     TemplateParamParent = 0;
   }
 
@@ -43,7 +48,6 @@ void Scope::Init(Scope *parent, unsigned flags) {
   if (flags & FnScope)            FnParent = this;
   if (flags & BreakScope)         BreakParent = this;
   if (flags & ContinueScope)      ContinueParent = this;
-  if (flags & ControlScope)       ControlParent = this;
   if (flags & BlockScope)         BlockParent = this;
   if (flags & TemplateParamScope) TemplateParamParent = this;