Add X32 port into V8

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 8840 matching lines @@
   MaybeObject* x;
   MaybeObject* y;
 };
 
 static inline ObjectPair MakePair(MaybeObject* x, MaybeObject* y) {
   ObjectPair result = {x, y};
   // Pointers x and y returned in rax and rdx, in AMD-x64-abi.
   // In Win64 they are assigned to a hidden first argument.
   return result;
 }
+#elif V8_TARGET_ARCH_X32
+// For x32 a 128-bit struct return is done as rax and rdx from the ObjectPair
+// are used in the full codegen and Crankshaft compiler. An alternative is
+// using uint64_t and modifying full codegen and Crankshaft compiler.
+struct ObjectPair {
+  MaybeObject* x;
+  uint32_t x_upper;
+  MaybeObject* y;
+  uint32_t y_upper;
+};
+
+static inline ObjectPair MakePair(MaybeObject* x, MaybeObject* y) {
+  ObjectPair result = {x, 0, y, 0};
+  // Pointers x and y returned in rax and rdx, in x32-abi.
+  return result;
+}
 #else
 typedef uint64_t ObjectPair;
 static inline ObjectPair MakePair(MaybeObject* x, MaybeObject* y) {
   return reinterpret_cast<uint32_t>(x) |
       (reinterpret_cast<ObjectPair>(y) << 32);
 }
 #endif
 
 
 static inline MaybeObject* Unhole(Heap* heap,
@@ skipping 5075 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal