Subzero ARM: lowerArguments (GPR), basic legalize(), and lowerRet(i32, i64).

src/IceOperand.h

 //===- subzero/src/IceOperand.h - High-level operands -----------*- 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 Operand class and its target-independent
@@ skipping 28 matching lines @@
     kConstFloat,
     kConstDouble,
     kConstRelocatable,
     kConstUndef,
     kConst_Target, // leave space for target-specific constant kinds
     kConst_Num = kConst_Target + MaxTargetKinds,
     kVariable,
     kVariable_Target, // leave space for target-specific variable kinds
     kVariable_Num = kVariable_Target + MaxTargetKinds,
     // Target-specific operand classes use kTarget as the starting
-    // point for their Kind enum space.
+    // point for their Kind enum space. Note that the value-spaces are shared
+    // across targets. To avoid confusion over the definition of shared
+    // values, an object specific to one target should never be passed
+    // to a different target.
     kTarget
   };
   OperandKind getKind() const { return Kind; }
   Type getType() const { return Ty; }
 
   // Every Operand keeps an array of the Variables referenced in
   // the operand.  This is so that the liveness operations can get
   // quick access to the variables of interest, without having to dig
   // so far into the operand.
   SizeT getNumVars() const { return NumVars; }
@@ skipping 568 matching lines @@
 private:
   const Cfg *Func;
   MetadataKind Kind;
   std::vector<VariableTracking> Metadata;
   const static InstDefList NoDefinitions;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEOPERAND_H