I'm introducing a new machine model to simultaneously allow simple
subtarget CPU descriptions and support new features of
MachineScheduler.

MachineModel has three categories of data:
1) Basic properties for coarse grained instruction cost model.
2) Scheduler Read/Write resources for simple per-opcode and operand cost model (TBD).
3) Instruction itineraties for detailed per-cycle reservation tables.

These will all live side-by-side. Any subtarget can use any
combination of them. Instruction itineraries will not change in the
near term. In the long run, I expect them to only be relevant for
in-order VLIW machines that have complex contraints and require a
precise scheduling/bundling model. Once itineraries are only actively
used by VLIW-ish targets, they could be replaced by something more
appropriate for those targets.

This tablegen backend rewrite sets things up for introducing
MachineModel type #2: per opcode/operand cost model.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159891 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/CodeGenTarget.h b/utils/TableGen/CodeGenTarget.h
index 85463da..2f8cee4 100644
--- a/utils/TableGen/CodeGenTarget.h
+++ b/utils/TableGen/CodeGenTarget.h
@@ -26,6 +26,7 @@
 namespace llvm {
 
 struct CodeGenRegister;
+class CodeGenSchedModels;
 class CodeGenTarget;
 
 // SelectionDAG node properties.
@@ -72,9 +73,12 @@
   void ReadInstructions() const;
   void ReadLegalValueTypes() const;
 
+  mutable CodeGenSchedModels *SchedModels;
+
   mutable std::vector<const CodeGenInstruction*> InstrsByEnum;
 public:
   CodeGenTarget(RecordKeeper &Records);
+  ~CodeGenTarget();
 
   Record *getTargetRecord() const { return TargetRec; }
   const std::string &getName() const;
@@ -96,7 +100,7 @@
   ///
   Record *getAsmParserVariant(unsigned i) const;
 
-  /// getAsmParserVariantCount - Return the AssmblyParserVariant definition 
+  /// getAsmParserVariantCount - Return the AssmblyParserVariant definition
   /// available for this target.
   ///
   unsigned getAsmParserVariantCount() const;
@@ -139,6 +143,8 @@
     return false;
   }
 
+  CodeGenSchedModels &getSchedModels() const;
+
 private:
   DenseMap<const Record*, CodeGenInstruction*> &getInstructions() const {
     if (Instructions.empty()) ReadInstructions();