Create a new InstrEmitter class for translating SelectionDAG nodes
into MachineInstrs. This is mostly just moving the code from
ScheduleDAGSDNodesEmit.cpp into a new class. This decouples MachineInstr
emitting from scheduling.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83699 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
index 9ca6d22..d53de34 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
@@ -14,6 +14,7 @@
 
 #define DEBUG_TYPE "pre-RA-sched"
 #include "ScheduleDAGSDNodes.h"
+#include "InstrEmitter.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetInstrInfo.h"
@@ -181,7 +182,7 @@
       if (N->isMachineOpcode() &&
           TII->get(N->getMachineOpcode()).getImplicitDefs()) {
         SU->hasPhysRegClobbers = true;
-        unsigned NumUsed = CountResults(N);
+        unsigned NumUsed = InstrEmitter::CountResults(N);
         while (NumUsed != 0 && !N->hasAnyUseOfValue(NumUsed - 1))
           --NumUsed;    // Skip over unused values at the end.
         if (NumUsed > TII->get(N->getMachineOpcode()).getNumDefs())
@@ -250,31 +251,6 @@
     }
 }
 
-/// CountResults - The results of target nodes have register or immediate
-/// operands first, then an optional chain, and optional flag operands (which do
-/// not go into the resulting MachineInstr).
-unsigned ScheduleDAGSDNodes::CountResults(SDNode *Node) {
-  unsigned N = Node->getNumValues();
-  while (N && Node->getValueType(N - 1) == MVT::Flag)
-    --N;
-  if (N && Node->getValueType(N - 1) == MVT::Other)
-    --N;    // Skip over chain result.
-  return N;
-}
-
-/// CountOperands - The inputs to target nodes have any actual inputs first,
-/// followed by an optional chain operand, then an optional flag operand.
-/// Compute the number of actual operands that will go into the resulting
-/// MachineInstr.
-unsigned ScheduleDAGSDNodes::CountOperands(SDNode *Node) {
-  unsigned N = Node->getNumOperands();
-  while (N && Node->getOperand(N - 1).getValueType() == MVT::Flag)
-    --N;
-  if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
-    --N; // Ignore chain if it exists.
-  return N;
-}
-
 void ScheduleDAGSDNodes::dumpNode(const SUnit *SU) const {
   if (!SU->getNode()) {
     errs() << "PHYS REG COPY\n";
@@ -293,3 +269,43 @@
     FlaggedNodes.pop_back();
   }
 }
+
+/// EmitSchedule - Emit the machine code in scheduled order.
+MachineBasicBlock *ScheduleDAGSDNodes::
+EmitSchedule(DenseMap<MachineBasicBlock*, MachineBasicBlock*> *EM) {
+  InstrEmitter Emitter(BB, InsertPos);
+  DenseMap<SDValue, unsigned> VRBaseMap;
+  DenseMap<SUnit*, unsigned> CopyVRBaseMap;
+  for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
+    SUnit *SU = Sequence[i];
+    if (!SU) {
+      // Null SUnit* is a noop.
+      EmitNoop();
+      continue;
+    }
+
+    // For pre-regalloc scheduling, create instructions corresponding to the
+    // SDNode and any flagged SDNodes and append them to the block.
+    if (!SU->getNode()) {
+      // Emit a copy.
+      EmitPhysRegCopy(SU, CopyVRBaseMap);
+      continue;
+    }
+
+    SmallVector<SDNode *, 4> FlaggedNodes;
+    for (SDNode *N = SU->getNode()->getFlaggedNode(); N;
+         N = N->getFlaggedNode())
+      FlaggedNodes.push_back(N);
+    while (!FlaggedNodes.empty()) {
+      Emitter.EmitNode(FlaggedNodes.back(), SU->OrigNode != SU, SU->isCloned,
+                       VRBaseMap, EM);
+      FlaggedNodes.pop_back();
+    }
+    Emitter.EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned,
+                     VRBaseMap, EM);
+  }
+
+  BB = Emitter.getBlock();
+  InsertPos = Emitter.getInsertPos();
+  return BB;
+}