Introduce the ability to insert IACA (Intel Architecture Code Analyzer) marks to

src/IceTargetLoweringX86Base.h

 //===- subzero/src/IceTargetLoweringX86Base.h - x86 lowering ----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 564 matching lines @@
     _set_dest_nonkillable();
     Context.insert(InstFakeUse::create(Func, Src));
   }
   void _xor(Variable *Dest, Operand *Src0) {
     Context.insert(Traits::Insts::Xor::create(Func, Dest, Src0));
   }
   void _xor_rmw(typename Traits::X86OperandMem *DestSrc0, Operand *Src1) {
     Context.insert(Traits::Insts::XorRMW::create(Func, DestSrc0, Src1));
   }
 
+  void _iaca_start() { Context.insert(Traits::Insts::IacaStart::create(Func)); }
+  void _iaca_end() { Context.insert(Traits::Insts::IacaEnd::create(Func)); }
+
+  /// This class helps wrap IACA markers around the code generated by the
+  /// current scope. It means you don't need to put an end before each return.
+  class ScopedIacaMark {
+    ScopedIacaMark(const ScopedIacaMark &) = delete;
+    ScopedIacaMark &operator=(const ScopedIacaMark &) = delete;
+
+  public:
+    ScopedIacaMark(TargetX86Base *Lowering) : Lowering(Lowering) {
+      Lowering->_iaca_start();
+    }
+    ~ScopedIacaMark() { end(); }
+    void end() {
+      if (!Lowering)
+        return;
+      Lowering->_iaca_end();
+      Lowering = nullptr;
+    }
+
+  private:
+    TargetX86Base *Lowering;
+  };
+
   bool optimizeScalarMul(Variable *Dest, Operand *Src0, int32_t Src1);
   void findRMW();
 
   typename Traits::InstructionSet InstructionSet =
       Traits::InstructionSet::Begin;
   bool IsEbpBasedFrame = false;
   bool NeedsStackAlignment = false;
   size_t SpillAreaSizeBytes = 0;
   llvm::SmallBitVector TypeToRegisterSet[IceType_NUM];
   llvm::SmallBitVector ScratchRegs;
@@ skipping 32 matching lines @@
   }
 
   BoolFolding FoldingInfo;
 };
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #include "IceTargetLoweringX86BaseImpl.h"
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASE_H