Enhance address mode recovery

unittest/AssemblerX8632/ControlFlow.cpp

 //===- subzero/unittest/AssemblerX8632/ControleFlow.cpp -------------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 #include "IceAssemblerX8632.h"
 #include "AssemblerX8632/TestUtil.h"
@@ skipping 115 matching lines @@
   __ hlt();
   __ hlt();
   __ hlt();
   __ hlt();
   __ hlt();
   __ hlt();
   __ hlt();
   __ hlt();
   __ hlt();
   __ mov(IceType_i32, GPRRegister::Encoded_Reg_eax, Immediate(0xf1f2f300));
-  __ call(Address(GPRRegister::Encoded_Reg_esp, 0));
+  static constexpr AssemblerFixup *Fixup = nullptr;

[Jim Stichnoth, 2015/10/27 22:19:52]

Is there some place you could put a single instance of:

  static constexpr AssemblerFixup *NoFixup = nullptr;

and then use NoFixup as the Address() arg?  Cutting down the repetition of the
NoFixup definitions.

I would be OK with a "#define NoFixup nullptr" if there isn't a common
superclass.

[sehr, 2015/10/27 23:24:05]

Added a NoFixup constexpr to the interface of AssemblerFixup.  Great suggestion.

+  __ call(Address(GPRRegister::Encoded_Reg_esp, 0, Fixup));
   __ popl(GPRRegister::Encoded_Reg_edx);
 
   AssembledTest test = assemble();
 
   test.run();
 
   EXPECT_EQ(0xf1f2f3f4, test.eax());
 }
 
 TEST_F(AssemblerX8632Test, Jmp) {
@@ skipping 88 matching lines @@
   TestImplReg(edi);
 
 #undef TestImplReg
 #undef TestImplAddr
 }
 
 } // end of anonymous namespace
 } // end of namespace Test
 } // end of namespace X8632
 } // end of namespace Ice