Move register class name strings to a single array in MCRegisterInfo to reduce static table size and number of relocation entries.

Indices into the table are stored in each MCRegisterClass instead of a pointer. A new method, getRegClassName, is added to MCRegisterInfo and TargetRegisterInfo to lookup the string in the table.

llvm-svn: 222118
diff --git a/llvm/lib/CodeGen/ExecutionDepsFix.cpp b/llvm/lib/CodeGen/ExecutionDepsFix.cpp
index 7afef96..3680498 100644
--- a/llvm/lib/CodeGen/ExecutionDepsFix.cpp
+++ b/llvm/lib/CodeGen/ExecutionDepsFix.cpp
@@ -720,7 +720,7 @@
   assert(NumRegs == RC->getNumRegs() && "Bad regclass");
 
   DEBUG(dbgs() << "********** FIX EXECUTION DEPENDENCIES: "
-               << RC->getName() << " **********\n");
+               << TRI->getRegClassName(RC) << " **********\n");
 
   // If no relevant registers are used in the function, we can skip it
   // completely.