Add warning for falling off the end of a function that should return a

value.  This is on by default, and controlled by -Wreturn-type (-Wmost
-Wall).  I believe there should be very few false positives, though
the most interesting case would be:

  int() { bar(); }

when bar does:

  bar() { while (1) ; }

Here, we assume functions return, unless they are marked with the
noreturn attribute.  I can envision a fixit note for functions that
never return normally that don't have a noreturn attribute to add a
noreturn attribute.

If anyone spots other false positives, let me know!

llvm-svn: 76821

1 files changed, 5 insertions, 1 deletions

diff --git a/clang/lib/Sema/Sema.h b/clang/lib/Sema/Sema.h
index 78d64b53c09..3bb763a13f8 100644
--- a/clang/lib/Sema/Sema.h
+++ b/clang/lib/Sema/Sema.h
@@ -801,10 +801,14 @@ public:
                                       SourceLocation MemberLoc,
                                       IdentifierInfo &Member);
                
-  /// Helpers for dealing with function parameters.
+  /// Helpers for dealing with functions.
+  void CheckFallThroughForFunctionDef(Decl *D, Stmt *Body);
   bool CheckParmsForFunctionDef(FunctionDecl *FD);
   void CheckCXXDefaultArguments(FunctionDecl *FD);
   void CheckExtraCXXDefaultArguments(Declarator &D);
+  enum ControlFlowKind { NeverFallThrough = 0, MaybeFallThrough = 1,
+                         AlwaysFallThrough = 2 };
+  ControlFlowKind CheckFallThrough(Stmt *);
 
   Scope *getNonFieldDeclScope(Scope *S);