[MachineOutliner][NFC] Don't create outlined sequence from integer mapping

Some gardening/refactoring.

It's cleaner to copy the instructions into the MachineFunction using the first
candidate instead of going to the mapper.

Also, by doing this we can remove the Seq member from OutlinedFunction entirely.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348390 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineOutliner.h

@@ -179,10 +179,6 @@ public:
   /// This is initialized after we go through and create the actual function.
   MachineFunction *MF = nullptr;
 
-  /// The sequence of integers corresponding to the instructions in this
-  /// function.
-  std::vector<unsigned> Sequence;
-
   /// Represents the size of a sequence in bytes. (Some instructions vary
   /// widely in size, so just counting the instructions isn't very useful.)
   unsigned SequenceSize;
@@ -225,6 +221,9 @@ public:
                                             : NotOutlinedCost - OutlinedCost;
   }
 
+  /// Return the number of instructions in this sequence.
+  unsigned getNumInstrs() const { return Candidates[0]->getLength(); }
+
   OutlinedFunction(std::vector<Candidate> &Cands,
                    unsigned SequenceSize, unsigned FrameOverhead,
                    unsigned FrameConstructionID)

lib/CodeGen/MachineOutliner.cpp

@@ -1041,7 +1041,7 @@ void MachineOutliner::emitOutlinedFunctionRemark(OutlinedFunction &OF) {
   MachineOptimizationRemark R(DEBUG_TYPE, "OutlinedFunction",
                               MBB->findDebugLoc(MBB->begin()), MBB);
   R << "Saved " << NV("OutliningBenefit", OF.getBenefit()) << " bytes by "
-    << "outlining " << NV("Length", OF.Sequence.size()) << " instructions "
+    << "outlining " << NV("Length", OF.getNumInstrs()) << " instructions "
     << "from " << NV("NumOccurrences", OF.getOccurrenceCount())
     << " locations. "
     << "(Found at: ";
@@ -1139,12 +1139,6 @@ unsigned MachineOutliner::findCandidates(
     if (OF.Candidates.size() < 2)
       continue;
 
-    std::vector<unsigned> Seq;
-    unsigned StartIdx = RS.StartIndices[0]; // Grab any start index.
-    for (unsigned i = StartIdx; i < StartIdx + StringLen; i++)
-      Seq.push_back(ST.Str[i]);
-    OF.Sequence = Seq;
-
     // Is it better to outline this candidate than not?
     if (OF.getBenefit() < 1) {
       emitNotOutliningCheaperRemark(StringLen, CandidatesForRepeatedSeq, OF);
@@ -1342,7 +1336,8 @@ MachineOutliner::createOutlinedFunction(Module &M, const OutlinedFunction &OF,
   // function. This makes sure the outlined function knows what kinds of
   // instructions are going into it. This is fine, since all parent functions
   // must necessarily support the instructions that are in the outlined region.
-  const Function &ParentFn = OF.Candidates.front()->getMF()->getFunction();
+  Candidate &FirstCand = *OF.Candidates.front();
+  const Function &ParentFn = FirstCand.getMF()->getFunction();
   if (ParentFn.hasFnAttribute("target-features"))
     F->addFnAttr(ParentFn.getFnAttribute("target-features"));
 
@@ -1359,11 +1354,9 @@ MachineOutliner::createOutlinedFunction(Module &M, const OutlinedFunction &OF,
   // Insert the new function into the module.
   MF.insert(MF.begin(), &MBB);
 
-  // Copy over the instructions for the function using the integer mappings in
-  // its sequence.
-  for (unsigned Str : OF.Sequence) {
-    MachineInstr *NewMI =
-        MF.CloneMachineInstr(Mapper.IntegerInstructionMap.find(Str)->second);
+  for (auto I = FirstCand.front(), E = std::next(FirstCand.back()); I != E;
+       ++I) {
+    MachineInstr *NewMI = MF.CloneMachineInstr(&*I);
     NewMI->dropMemRefs(MF);
 
     // Don't keep debug information for outlined instructions.