IR: Use a bitmask to access GlobalObject subclass data

Make room for more than just `Function::isMaterializable()` in the
`GlobalObject` subclass data bitfield.  Since we're treating it like a
bitfield, change `Function::Function()` to zero-out the whole thing.

llvm-svn: 235770

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/IR/Function.cpp b/llvm/lib/IR/Function.cpp
index d3a09348220..227dfef9e98 100644
--- a/llvm/lib/IR/Function.cpp
+++ b/llvm/lib/IR/Function.cpp
@@ -206,10 +206,12 @@ void Argument::removeAttr(AttributeSet AS) {
 //===----------------------------------------------------------------------===//
 
 bool Function::isMaterializable() const {
-  return getGlobalObjectSubClassData();
+  return getGlobalObjectSubClassData() & IsMaterializableBit;
 }
 
-void Function::setIsMaterializable(bool V) { setGlobalObjectSubClassData(V); }
+void Function::setIsMaterializable(bool V) {
+  setGlobalObjectBit(IsMaterializableBit, V);
+}
 
 LLVMContext &Function::getContext() const {
   return getType()->getContext();
@@ -244,7 +246,7 @@ Function::Function(FunctionType *Ty, LinkageTypes Linkage, const Twine &name,
       Ty(Ty) {
   assert(FunctionType::isValidReturnType(getReturnType()) &&
          "invalid return type");
-  setIsMaterializable(false);
+  setGlobalObjectSubClassData(0);
   SymTab = new ValueSymbolTable();
 
   // If the function has arguments, mark them as lazily built.