Add MachineBasicBlock::getName, and use it in place of getBasicBlock()->getName.

Fix debug code that assumes getBasicBlock never returns NULL.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89428 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp
index c836286..10c8066 100644
--- a/lib/CodeGen/VirtRegRewriter.cpp
+++ b/lib/CodeGen/VirtRegRewriter.cpp
@@ -1600,7 +1600,7 @@
                   std::vector<MachineOperand*> &KillOps) {
 
     DEBUG(errs() << "\n**** Local spiller rewriting MBB '"
-          << MBB.getBasicBlock()->getName() << "':\n");
+          << MBB.getName() << "':\n");
 
     MachineFunction &MF = *MBB.getParent();