Codegen pass definition cleanup. No functionality.

Moving toward a uniform style of pass definition to allow easier target configuration.
Globally declare Pass ID.
Globally declare pass initializer.
Use INITIALIZE_PASS consistently.
Add a call to the initializer from CodeGen.cpp.
Remove redundant "createPass" functions and "getPassName" methods.

While cleaning up declarations, cleaned up comments (sorry for large diff).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150100 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMTargetMachine.cpp b/lib/Target/ARM/ARMTargetMachine.cpp
index 35d18d3..44229ad 100644
--- a/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/lib/Target/ARM/ARMTargetMachine.cpp
@@ -170,7 +170,7 @@
 
   if (getOptLevel() != CodeGenOpt::None) {
     if (!getARMSubtarget().isThumb1Only())
-      PM.add(createIfConverterPass());
+      addPass(IfConverterID);
   }
   if (getARMSubtarget().isThumb2())
     PM.add(createThumb2ITBlockPass());
@@ -184,7 +184,7 @@
       PM.add(createThumb2SizeReductionPass());
 
     // Constant island pass work on unbundled instructions.
-    PM.add(createUnpackMachineBundlesPass());
+    addPass(UnpackMachineBundlesID);
   }
 
   PM.add(createARMConstantIslandPass());