llvm dev - Sep 2019 - Attribute C-interface since LLVM-4.0

I try to guess how the new Attribute C-interface since LLVM-3.9 works, but 
it seems I have not guessed correctly so far. See attached example. First 
file uses the API before LLVM-3.9 and second file uses the API starting 
with LLVM-3.9. Essentially I replaced

   LLVMAddInstrAttribute
     (call_exp, LLVMAttributeFunctionIndex, LLVMReadNoneAttribute);

by

   unsigned attrKind = LLVMGetEnumAttributeKindForName("readnone", 8);
   LLVMContextRef context = LLVMGetGlobalContext();
   LLVMAttributeRef attr = LLVMCreateEnumAttribute (context, attrKind, 0);
   LLVMAddAttributeAtIndex(call_exp, LLVMAttributeFunctionIndex, attr);

But in the generated Bitcode file no "readnone" attribute shows up.
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On Tue, 17 Sep 2019, Henning Thielemann wrote:
>  unsigned attrKind = LLVMGetEnumAttributeKindForName("readnone",
8);
>  LLVMContextRef context = LLVMGetGlobalContext();
>  LLVMAttributeRef attr = LLVMCreateEnumAttribute (context, attrKind, 0);
>  LLVMAddAttributeAtIndex(call_exp, LLVMAttributeFunctionIndex, attr);
>
> But in the generated Bitcode file no "readnone" attribute shows
up.
The solution is: It must be LLVMAddCallSiteAttribute instead of 
LLVMAddAttributeAtIndex.