Subzero: Add rudimentary statistics on generated code.

src/IceInst.h

 //===- subzero/src/IceInst.h - High-level instructions ----------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the Inst class and its target-independent
@@ skipping 83 matching lines @@
 
   // Updates the status of the Variables contained within the
   // instruction.  In particular, it marks where the Dest variable is
   // first assigned, and it tracks whether variables are live across
   // basic blocks, i.e. used in a different block from their definition.
   void updateVars(CfgNode *Node);
 
   void livenessLightweight(llvm::BitVector &Live);
   void liveness(InstNumberT InstNumber, llvm::BitVector &Live,
                 Liveness *Liveness, const CfgNode *Node);
+
+  // Get the number of native instructions that this instruction
+  // ultimately emits.  By default, high-level instructions don't
+  // result in any native instructions, and a target-specific
+  // instruction results in a single native instruction.
+  virtual uint32_t getEmitInstCount() const { return 0; }
   virtual void emit(const Cfg *Func) const;
   virtual void dump(const Cfg *Func) const;
   virtual void dumpExtras(const Cfg *Func) const;
   void dumpDecorated(const Cfg *Func) const;
   void emitSources(const Cfg *Func) const;
   void dumpSources(const Cfg *Func) const;
   void dumpDest(const Cfg *Func) const;
   virtual bool isRedundantAssign() const { return false; }
 
   virtual ~Inst() {}
@@ skipping 623 matching lines @@
   virtual ~InstFakeKill() {}
 
   // This instruction is ignored if Linked->isDeleted() is true.
   const Inst *Linked;
 };
 
 // The Target instruction is the base class for all target-specific
 // instructions.
 class InstTarget : public Inst {
 public:
+  virtual uint32_t getEmitInstCount() const { return 1; }
   virtual void emit(const Cfg *Func) const = 0;
   virtual void dump(const Cfg *Func) const;
   virtual void dumpExtras(const Cfg *Func) const;
   static bool classof(const Inst *Inst) { return Inst->getKind() >= Target; }
 
 protected:
   InstTarget(Cfg *Func, InstKind Kind, SizeT MaxSrcs, Variable *Dest)
       : Inst(Func, Kind, MaxSrcs, Dest) {
     assert(Kind >= Target);
   }
   InstTarget(const InstTarget &) LLVM_DELETED_FUNCTION;
   InstTarget &operator=(const InstTarget &) LLVM_DELETED_FUNCTION;
   virtual ~InstTarget() {}
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINST_H