Introduce the notion of function addresses in Subzero.

crosstest/test_global_main.cpp

 //===- subzero/crosstest/test_global_main.cpp - Driver for tests ----------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Driver for crosstesting global variable access operations.
 //
 //===----------------------------------------------------------------------===//
 
 /* crosstest.py --test=test_global.cpp \
    --driver=test_global_main.cpp --prefix=Subzero_ --output=test_global */
 
 #include <stdint.h>
 #include <cstdlib>
 #include <iostream>
 
 #include "test_global.h"
 namespace Subzero_ {
 #include "test_global.h"
 }
 
+int ExternName1 = 36363;
+float ExternName2 = 357.05e-10;
+char ExternName3[] = {'a', 'b', 'c'};
+struct {
+  int a;
+  float b;
+  double d;
+} ExternName4 = {-111, 2.69, 55.19};
+double ExternName5 = 3.44e26;
+
 int main(int argc, char **argv) {
   size_t TotalTests = 0;
   size_t Passes = 0;
   size_t Failures = 0;
 
   const uint8_t *SzArray, *LlcArray;
   size_t SzArrayLen, LlcArrayLen;
 
   size_t NumArrays = getNumArrays();
   for (size_t i = 0; i < NumArrays; ++i) {
@@ skipping 20 matching lines @@
                   << ", SzArray[" << i << "] = " << (int)SzArray[i]
                   << "\n";
       }
     }
   }
 
   std::cout << "TotalTests=" << TotalTests << " Passes=" << Passes
             << " Failures=" << Failures << "\n";
   return Failures;
 }