Index: include/llvm-c/Core.h
===================================================================
--- include/llvm-c/Core.h
+++ include/llvm-c/Core.h
@@ -490,6 +490,11 @@
 unsigned LLVMGetAttrKindID(const char *Name, size_t SLen);
 
 /**
+ * Create an attribute without argument.
+ */
+LLVMAttributeRef LLVMCreateAttribute(LLVMContextRef C, unsigned KindID);
+
+/**
  * @}
  */
 
@@ -1977,6 +1982,21 @@
 void LLVMRemoveFunctionAttr(LLVMValueRef Fn, LLVMAttribute PA);
 
 /**
+ * Add a return attribute to a function.
+ */
+void LLVMAddReturnAttr(LLVMValueRef Fn, LLVMAttributeRef A);
+
+/**
+ * Remove a return attribute from a function.
+ */
+void LLVMRemoveReturnAttr(LLVMValueRef Fn, unsigned KindID);
+
+/**
+ * Check if a function's return has an attribute.
+ */
+LLVMAttributeRef LLVMGetReturnAttr(LLVMValueRef Fn, unsigned KindID);
+
+/**
  * @defgroup LLVMCCoreValueFunctionParameters Function Parameters
  *
  * Functions in this group relate to arguments/parameters on functions.
Index: include/llvm-c/Types.h
===================================================================
--- include/llvm-c/Types.h
+++ include/llvm-c/Types.h
@@ -109,6 +109,13 @@
 typedef struct LLVMOpaqueUse *LLVMUseRef;
 
 /**
+ * Used to represent an attributes.
+ *
+ * @see llvm::Attribute
+ */
+typedef struct LLVMOpaqueAttributeRef *LLVMAttributeRef;
+
+/**
  * @see llvm::DiagnosticInfo
  */
 typedef struct LLVMOpaqueDiagnosticInfo *LLVMDiagnosticInfoRef;
Index: include/llvm/IR/Attributes.h
===================================================================
--- include/llvm/IR/Attributes.h
+++ include/llvm/IR/Attributes.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/Optional.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/PointerLikeTypeTraits.h"
+#include "llvm-c/Types.h"
 #include <bitset>
 #include <cassert>
 #include <map>
@@ -169,8 +170,28 @@
   void Profile(FoldingSetNodeID &ID) const {
     ID.AddPointer(pImpl);
   }
+
+  /// \brief Return a raw pointer that uniquely identifies this attribute.
+  void *getRawPointer() const {
+    return pImpl;
+  }
+
+  /// \brief Get an attribute from a raw pointer created by getRawPointer.
+  static Attribute fromRawPointer(void *RawPtr) {
+    return Attribute(reinterpret_cast<AttributeImpl*>(RawPtr));
+  }
 };
 
+// Specialized opaque value conversions.
+inline LLVMAttributeRef wrap(Attribute Attr) {
+  return reinterpret_cast<LLVMAttributeRef>(Attr.getRawPointer());
+}
+
+// Specialized opaque value conversions.
+inline Attribute unwrap(LLVMAttributeRef Attr) {
+  return Attribute::fromRawPointer(Attr);
+}
+
 //===----------------------------------------------------------------------===//
 /// \class
 /// \brief This class holds the attributes for a function, its return value, and
Index: include/llvm/IR/Function.h
===================================================================
--- include/llvm/IR/Function.h
+++ include/llvm/IR/Function.h
@@ -237,6 +237,9 @@
   /// @brief adds the attribute to the list of attributes.
   void addAttribute(unsigned i, Attribute::AttrKind attr);
 
+  /// @brief adds the attribute to the list of attributes.
+  void addAttribute(unsigned i, Attribute Attr);
+
   /// @brief adds the attributes to the list of attributes.
   void addAttributes(unsigned i, AttributeSet attrs);
 
Index: lib/IR/Core.cpp
===================================================================
--- lib/IR/Core.cpp
+++ lib/IR/Core.cpp
@@ -125,12 +125,11 @@
 #include "AttributesCompatFunc.inc"
 
 unsigned LLVMGetAttrKindID(const char *Name, size_t SLen) {
-  auto K = getAttrKindFromName(StringRef(Name, SLen));
-  if (K == Attribute::None) {
-    return 0;
-  }
+  return getAttrKindFromName(StringRef(Name, SLen));
+}
 
-  return AttributeImpl::getAttrMask(K);
+LLVMAttributeRef LLVMCreateAttribute(LLVMContextRef C, unsigned KindID) {
+  return wrap(Attribute::get(*unwrap(C), (Attribute::AttrKind)KindID));
 }
 
 char *LLVMGetDiagInfoDescription(LLVMDiagnosticInfoRef DI) {
@@ -1821,6 +1820,19 @@
   return (LLVMAttribute)PAL.Raw(AttributeSet::FunctionIndex);
 }
 
+void LLVMAddReturnAttr(LLVMValueRef Fn, LLVMAttributeRef A) {
+  unwrap<Function>(Fn)->addAttribute(AttributeSet::ReturnIndex, unwrap(A));
+}
+
+void LLVMRemoveReturnAttr(LLVMValueRef Fn, unsigned KindID) {
+  unwrap<Function>(Fn)->removeAttribute(AttributeSet::ReturnIndex,
+                                        (Attribute::AttrKind)KindID);
+}
+
+LLVMAttributeRef LLVMGetReturnAttr(LLVMValueRef Fn, unsigned KindID) {
+  return wrap(unwrap<Function>(Fn)->getFnAttribute((Attribute::AttrKind)KindID));
+}
+
 /*--.. Operations on parameters ............................................--*/
 
 unsigned LLVMCountParams(LLVMValueRef FnRef) {
Index: lib/IR/Function.cpp
===================================================================
--- lib/IR/Function.cpp
+++ lib/IR/Function.cpp
@@ -370,6 +370,12 @@
   setAttributes(PAL);
 }
 
+void Function::addAttribute(unsigned i, Attribute Attr) {
+  AttributeSet PAL = getAttributes();
+  PAL = PAL.addAttribute(getContext(), i, Attr);
+  setAttributes(PAL);
+}
+
 void Function::addAttributes(unsigned i, AttributeSet attrs) {
   AttributeSet PAL = getAttributes();
   PAL = PAL.addAttributes(getContext(), i, attrs);