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

lib/CodeGen/CodePlacementOpt.cpp

@@ -39,9 +39,6 @@ namespace {
     CodePlacementOpt() : MachineFunctionPass(ID) {}
 
     virtual bool runOnMachineFunction(MachineFunction &MF);
-    virtual const char *getPassName() const {
-      return "Code Placement Optimizer";
-    }
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.addRequired<MachineLoopInfo>();
@@ -69,9 +66,9 @@ namespace {
   char CodePlacementOpt::ID = 0;
 } // end anonymous namespace
 
-FunctionPass *llvm::createCodePlacementOptPass() {
-  return new CodePlacementOpt();
-}
+char &llvm::CodePlacementOptID = CodePlacementOpt::ID;
+INITIALIZE_PASS(CodePlacementOpt, "code-placement",
+                "Code Placement Optimizer", false, false)
 
 /// HasFallthrough - Test whether the given branch has a fallthrough, either as
 /// a plain fallthrough or as a fallthrough case of a conditional branch.