Add Marker attribute to LLVMBitCodes.h and BitcodeReader.cpp***

***Add encoding for Marker attribute in BitcodeWriter.cpp

Author: gmh5225

llvm/include/llvm/Bitcode/LLVMBitCodes.h

@@ -732,6 +732,7 @@ enum AttributeKindCodes {
   ATTR_KIND_WRITABLE = 97,
   ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE = 98,
   ATTR_KIND_DEAD_ON_UNWIND = 99,
+  ATTR_KIND_MARKER = 100,
 };
 
 enum ComdatSelectionKindCodes {

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -2092,6 +2092,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
     return Attribute::Hot;
   case bitc::ATTR_KIND_PRESPLIT_COROUTINE:
     return Attribute::PresplitCoroutine;
+  case bitc::ATTR_KIND_MARKER:
+    return Attribute::Marker;
   case bitc::ATTR_KIND_VOLATILE_FUNCTION:
     return Attribute::IsVolatileFunction;
   case bitc::ATTR_KIND_DISABLE_BLOCK_PLACEMENT_PASS:

llvm/lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -834,6 +834,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
   case Attribute::EmptyKey:
   case Attribute::TombstoneKey:
     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
+  case Attribute::Marker:
+    return bitc::ATTR_KIND_MARKER;
   case Attribute::IsVolatileFunction:
     return bitc::ATTR_KIND_VOLATILE_FUNCTION;
   case Attribute::DisableBlockPlacementPass: