Move a few containers out of ScheduleDAGInstrs::BuildSchedGraph
and into the ScheduleDAGInstrs class, so that they don't get
destructed and re-constructed for each block. This fixes a
compile-time hot spot in the post-pass scheduler.

To help facilitate this, tidy and do some minor reorganization
in the scheduler constructor functions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62275 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAGPrinter.cpp b/lib/CodeGen/ScheduleDAGPrinter.cpp
index 2553960..e2ae5a0 100644
--- a/lib/CodeGen/ScheduleDAGPrinter.cpp
+++ b/lib/CodeGen/ScheduleDAGPrinter.cpp
@@ -34,7 +34,7 @@
   template<>
   struct DOTGraphTraits<ScheduleDAG*> : public DefaultDOTGraphTraits {
     static std::string getGraphName(const ScheduleDAG *G) {
-      return G->MF->getFunction()->getName();
+      return G->MF.getFunction()->getName();
     }
 
     static bool renderGraphFromBottomUp() {
@@ -83,8 +83,8 @@
 void ScheduleDAG::viewGraph() {
 // This code is only for debugging!
 #ifndef NDEBUG
-  ViewGraph(this, "dag." + MF->getFunction()->getName(),
-            "Scheduling-Units Graph for " + MF->getFunction()->getName() + ':' +
+  ViewGraph(this, "dag." + MF.getFunction()->getName(),
+            "Scheduling-Units Graph for " + MF.getFunction()->getName() + ':' +
             BB->getBasicBlock()->getName());
 #else
   cerr << "ScheduleDAG::viewGraph is only available in debug builds on "