misched preparation: modularize schedule emission.

ScheduleDAG has nothing to do with how the instructions are scheduled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152206 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/PostRASchedulerList.cpp

@@ -145,6 +145,8 @@ namespace {
     ///
     void Schedule();
 
+    void EmitSchedule();
+
     /// Observe - Update liveness information to account for the current
     /// instruction, which will not be scheduled.
     ///
@@ -730,3 +732,37 @@ void SchedulePostRATDList::ListScheduleTopDown() {
          "The number of nodes scheduled doesn't match the expected number!");
 #endif // NDEBUG
 }
+
+// EmitSchedule - Emit the machine code in scheduled order.
+void SchedulePostRATDList::EmitSchedule() {
+  Begin = InsertPos;
+
+  // If first instruction was a DBG_VALUE then put it back.
+  if (FirstDbgValue)
+    BB->splice(InsertPos, BB, FirstDbgValue);
+
+  // Then re-insert them according to the given schedule.
+  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
+    if (SUnit *SU = Sequence[i])
+      BB->splice(InsertPos, BB, SU->getInstr());
+    else
+      // Null SUnit* is a noop.
+      TII->insertNoop(*BB, InsertPos);
+
+    // Update the Begin iterator, as the first instruction in the block
+    // may have been scheduled later.
+    if (i == 0)
+      Begin = prior(InsertPos);
+  }
+
+  // Reinsert any remaining debug_values.
+  for (std::vector<std::pair<MachineInstr *, MachineInstr *> >::iterator
+         DI = DbgValues.end(), DE = DbgValues.begin(); DI != DE; --DI) {
+    std::pair<MachineInstr *, MachineInstr *> P = *prior(DI);
+    MachineInstr *DbgValue = P.first;
+    MachineBasicBlock::iterator OrigPrivMI = P.second;
+    BB->splice(++OrigPrivMI, BB, DbgValue);
+  }
+  DbgValues.clear();
+  FirstDbgValue = NULL;
+}