/// attribute sets are immutable, this returns a new set.
AttributeSet addAttribute(LLVMContext &C, unsigned Index,
StringRef Kind) const;
AttributeSet addAttribute(LLVMContext &C, unsigned Index,
StringRef Kind, StringRef Value) const;
/// attribute sets are immutable, this returns a new set.
AttributeSet addAttribute(LLVMContext &C, unsigned Index,
StringRef Kind) const;
AttributeSet addAttribute(LLVMContext &C, unsigned Index,
StringRef Kind, StringRef Value) const;