Expands the use of Immediate and Operand wrappers.

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
===================================================================
--- runtime/vm/assembler_x64.h	(revision 40903)
+++ runtime/vm/assembler_x64.h	(working copy)
@@ -185,6 +185,9 @@
     }
   }
 
+  // This addressing mode does not exist.
+  Address(Register base, Register r);
+
   Address(Register index, ScaleFactor scale, int32_t disp) {
     ASSERT(index != RSP);  // Illegal addressing mode.
     SetModRM(0, RSP);
@@ -192,6 +195,9 @@
     SetDisp32(disp);
   }
 
+  // This addressing mode does not exist.
+  Address(Register index, ScaleFactor scale, Register r);
+
   Address(Register base, Register index, ScaleFactor scale, int32_t disp) {
     ASSERT(index != RSP);  // Illegal addressing mode.
     if ((disp == 0) && ((base & 7) != RBP)) {
@@ -208,6 +214,9 @@
     }
   }
 
+  // This addressing mode does not exist.
+  Address(Register base, Register index, ScaleFactor scale, Register r);
+
   Address(const Address& other) : Operand(other) { }
 
   Address& operator=(const Address& other) {
@@ -219,6 +228,9 @@
     return Address(base, disp, true);
   }
 
+  // This addressing mode does not exist.
+  static Address AddressBaseImm32(Register base, Register r);
+
  private:
   Address(Register base, int32_t disp, bool fixed) {
     ASSERT(fixed);
@@ -236,9 +248,15 @@
   FieldAddress(Register base, int32_t disp)
       : Address(base, disp - kHeapObjectTag) { }
 
+  // This addressing mode does not exist.
+  FieldAddress(Register base, Register r);
+
   FieldAddress(Register base, Register index, ScaleFactor scale, int32_t disp)
       : Address(base, index, scale, disp - kHeapObjectTag) { }
 
+  // This addressing mode does not exist.
+  FieldAddress(Register base, Register index, ScaleFactor scale, Register r);
+
   FieldAddress(const FieldAddress& other) : Address(other) { }
 
   FieldAddress& operator=(const FieldAddress& other) {