Extract renaming from D19181

[deadalnix]

Summary

This needs to get in before anything is released concerning attribute. If the old name gets in the wild, then we are stuck with it forever. Putting it in its own diff should getting that part at least in fast.

[Wallbraker]

Considering how long the other Attribute review is taking just remove the function all together, and put it in once we actually have the finished interface down.

Cheers, Jakob.

[whitequark]

LGTM.

[deadalnix]

@Walbraker as long as there is no date for the branch cut, I don't think we should make assumptions.

docs/ReleaseNotes.rst

 * The C API function LLVMLinkModules has been removed.
 
 * The C API function LLVMAddTargetData has been removed.
 
 * The C API function LLVMGetDataLayout is deprecated
   in favor of LLVMGetDataLayoutStr.
 
 * The C API enum LLVMAttribute is deprecated in favor of
-  LLVMGetAttrKindID.
+  LLVMGetAttributeKindForName.
 
 * ``TargetFrameLowering::eliminateCallFramePseudoInstr`` now returns an
   iterator to the next instruction instead of ``void``. Targets that previously
   did ``MBB.erase(I); return;`` now probably want ``return MBB.erase(I);``.
 
 * ``SelectionDAGISel::Select`` now returns ``void``. Out of tree targets will
   need to be updated to replace the argument node and remove any dead nodes in
   cases where they currently return an ``SDNode *`` from this interface.

include/llvm-c/Core.h

  *
  * See http://llvm.org/docs/LangRef.html#parameter-attributes
  * and http://llvm.org/docs/LangRef.html#function-attributes
  * for the list of available attributes.
  *
  * NB: Attribute names and/or id are subject to change without
  * going through the C API deprecation cycle.
  */
-unsigned LLVMGetAttrKindID(const char *Name, size_t SLen);
+unsigned LLVMGetAttributeKindForName(const char *Name, size_t SLen);
 
 /**
  * @}
  */
 
 /**
  * @defgroup LLVMCCoreModule Modules
  *

lib/IR/Core.cpp

 
 unsigned LLVMGetMDKindID(const char *Name, unsigned SLen) {
   return LLVMGetMDKindIDInContext(LLVMGetGlobalContext(), Name, SLen);
 }
 
 #define GET_ATTR_KIND_FROM_NAME
 #include "AttributesCompatFunc.inc"
 
-unsigned LLVMGetAttrKindID(const char *Name, size_t SLen) {
-  auto K = getAttrKindFromName(StringRef(Name, SLen));
-  if (K == Attribute::None) {
-    return 0;
-  }
-
-  return AttributeImpl::getAttrMask(K);
+unsigned LLVMGetAttributeKindForName(const char *Name, size_t SLen) {
+  return getAttrKindFromName(StringRef(Name, SLen));
 }
 
 char *LLVMGetDiagInfoDescription(LLVMDiagnosticInfoRef DI) {
   std::string MsgStorage;
   raw_string_ostream Stream(MsgStorage);
   DiagnosticPrinterRawOStream DP(Stream);
 
   unwrap(DI)->print(DP);