[MC] Reduce size of MCDataFragment by 8 bytes

Due to alignment, MCFragment was 1 byte over the 8 byte boundary, so
folding to bools into bitfields gives a nice space reduction.

Author: aengelke

llvm/include/llvm/MC/MCFragment.h

@@ -73,8 +73,8 @@ class MCFragment {
   FragmentType Kind;
 
 protected:
-  bool HasInstructions;
-  bool LinkerRelaxable = false;
+  bool HasInstructions : 1;
+  bool LinkerRelaxable : 1;
 
   MCFragment(FragmentType Kind, bool HasInstructions,
              MCSection *Parent = nullptr);

llvm/lib/MC/MCFragment.cpp

@@ -200,7 +200,7 @@ uint64_t llvm::computeBundlePadding(const MCAssembler &Assembler,
 MCFragment::MCFragment(FragmentType Kind, bool HasInstructions,
                        MCSection *Parent)
     : Parent(Parent), Atom(nullptr), Offset(~UINT64_C(0)), LayoutOrder(0),
-      Kind(Kind), HasInstructions(HasInstructions) {
+      Kind(Kind), HasInstructions(HasInstructions), LinkerRelaxable(false) {
   if (Parent && !isa<MCDummyFragment>(*this))
     Parent->addFragment(*this);
 }