Add range accessors for captures of a LambdaExpr.

[jdennett]

Summary

This adds LambdaExpr::captures(), LambdaExpr::explicit_captures()
and LambdaExpr::implicit_captures() as simple wrappers over the underlying
*_begin()/*_end() functions.

[jdennett]

Closed by commit rL209679 (authored by @jdennett).

include/clang/AST/ExprCXX.h

public:
   SourceLocation getCaptureDefaultLoc() const {
     return CaptureDefaultLoc;
   }
 
   /// \brief An iterator that walks over the captures of the lambda,
   /// both implicit and explicit.
   typedef const Capture *capture_iterator;
 
+  /// \brief An iterator over a range of lambda captures.
+  typedef llvm::iterator_range<capture_iterator> capture_range;
+
+  /// \brief Retrieve this lambda's captures.
+  capture_range captures() const;
+  
   /// \brief Retrieve an iterator pointing to the first lambda capture.
   capture_iterator capture_begin() const;
 
   /// \brief Retrieve an iterator pointing past the end of the
   /// sequence of lambda captures.
   capture_iterator capture_end() const;
 
   /// \brief Determine the number of captures in this lambda.
   unsigned capture_size() const { return NumCaptures; }
-  
+  /// \brief Retrieve this lambda's explicit captures.
+  capture_range explicit_captures() const;
+  
   /// \brief Retrieve an iterator pointing to the first explicit
   /// lambda capture.
   capture_iterator explicit_capture_begin() const;
 
   /// \brief Retrieve an iterator pointing past the end of the sequence of
   /// explicit lambda captures.
   capture_iterator explicit_capture_end() const;
 
+  /// \brief Retrieve this lambda's implicit captures.
+  capture_range implicit_captures() const;
+
   /// \brief Retrieve an iterator pointing to the first implicit
   /// lambda capture.
   capture_iterator implicit_capture_begin() const;
 
   /// \brief Retrieve an iterator pointing past the end of the sequence of
   /// implicit lambda captures.
   capture_iterator implicit_capture_end() const;
 

lib/AST/ExprCXX.cpp

 LambdaExpr::capture_iterator LambdaExpr::capture_begin() const {
   return getLambdaClass()->getLambdaData().Captures;
 }
 
 LambdaExpr::capture_iterator LambdaExpr::capture_end() const {
   return capture_begin() + NumCaptures;
 }
 
+LambdaExpr::capture_range LambdaExpr::captures() const {
+  return capture_range(capture_begin(), capture_end());
+}
+
 LambdaExpr::capture_iterator LambdaExpr::explicit_capture_begin() const {
   return capture_begin();
 }
 
 LambdaExpr::capture_iterator LambdaExpr::explicit_capture_end() const {
   struct CXXRecordDecl::LambdaDefinitionData &Data
     = getLambdaClass()->getLambdaData();
   return Data.Captures + Data.NumExplicitCaptures;
 }
 
+LambdaExpr::capture_range LambdaExpr::explicit_captures() const {
+  return capture_range(explicit_capture_begin(), explicit_capture_end());
+}
+
 LambdaExpr::capture_iterator LambdaExpr::implicit_capture_begin() const {
   return explicit_capture_end();
 }
 
 LambdaExpr::capture_iterator LambdaExpr::implicit_capture_end() const {
   return capture_end();
 }
 
+LambdaExpr::capture_range LambdaExpr::implicit_captures() const {
+  return capture_range(implicit_capture_begin(), implicit_capture_end());
+}
+
 ArrayRef<VarDecl *> 
 LambdaExpr::getCaptureInitIndexVars(capture_init_iterator Iter) const {
   assert(HasArrayIndexVars && "No array index-var data?");
   
   unsigned Index = Iter - capture_init_begin();
   assert(Index < getLambdaClass()->getLambdaData().NumCaptures &&
          "Capture index out-of-range");
   VarDecl **IndexVars = getArrayIndexVars();