Add ArrayRef<> interface to get the parameters of a FunctionDecl/ObjCMethodDecl.

This is an alternate interface to the separate iterator interfaces
provided by FunctionDecl and ObjCMethodDecl, which precede ArrayRef.

Providing this new interface is more convenient for some uses, and
likely the old interfaces should be removed.  I have not undertaken
that effort in this change because this API introduction may
solicit commentary and that was a larger change than I wanted
to introduce all at once to serve a direct purpose.

llvm-svn: 199466

clang/include/clang/AST/Decl.h

@@ -1851,6 +1851,12 @@ public:
     setParams(getASTContext(), NewParamInfo);
   }
 
+  // ArrayRef iterface to parameters.
+  // FIXME: Should one day replace iterator interface.
+  ArrayRef<ParmVarDecl*> parameters() const {
+    return llvm::makeArrayRef(ParamInfo, getNumParams());
+  }
+
   const ArrayRef<NamedDecl *> &getDeclsInPrototypeScope() const {
     return DeclsInPrototypeScope;
   }

clang/include/clang/AST/DeclObjC.h

@@ -314,8 +314,7 @@ public:
     if (hasStandardSelLocs())
       return getStandardSelectorLoc(Index, getSelector(),
                                    getSelLocsKind() == SelLoc_StandardWithSpace,
-                      llvm::makeArrayRef(const_cast<ParmVarDecl**>(getParams()),
-                                         NumParams),
+                                    parameters(),
                                    DeclEndLoc);
     return getStoredSelLocs()[Index];
   }
@@ -364,6 +363,13 @@ public:
     return param_begin() + getSelector().getNumArgs();
   }
 
+  // ArrayRef access to formal parameters.  This should eventually
+  // replace the iterator interface above.
+  ArrayRef<ParmVarDecl*> parameters() const {
+    return llvm::makeArrayRef(const_cast<ParmVarDecl**>(getParams()),
+                              NumParams);
+  }
+
   /// \brief Sets the method's parameters and selector source locations.
   /// If the method is implicit (not coming from source) \p SelLocs is
   /// ignored.