Remove V8_HOST_CAN_READ_UNALIGNED and its uses.

src/deoptimizer.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_DEOPTIMIZER_H_
 #define V8_DEOPTIMIZER_H_
 
 #include "src/v8.h"
 
 #include "src/allocation.h"
 #include "src/macro-assembler.h"
 #include "src/zone-inl.h"
 
 
 namespace v8 {
 namespace internal {
 
 
 static inline double read_double_value(Address p) {
-#ifdef V8_HOST_CAN_READ_UNALIGNED
-  return Memory::double_at(p);
-#else  // V8_HOST_CAN_READ_UNALIGNED
   // Prevent gcc from using load-double (mips ldc1) on (possibly)
   // non-64-bit aligned address.
   union conversion {
     double d;
     uint32_t u[2];
   } c;
-  c.u[0] = *reinterpret_cast<uint32_t*>(p);
-  c.u[1] = *reinterpret_cast<uint32_t*>(p + 4);
+  c.u[0] = Memory::uint32_at(p);

[Jakob Kummerow, 2014/09/12 11:08:44]

Since Memory::uint32_at does a reinterpret_cast<uint32_t*>, this is only safe
when p is 4-byte aligned. I understand that this is guaranteed by current
callers, but please add a comment and/or DCHECK to make it explicit.

[Sven Panne, 2014/09/12 13:12:08]

Even simpler: Just use memcpy...

+  c.u[1] = Memory::uint32_at(p + 4);
   return c.d;
-#endif  // V8_HOST_CAN_READ_UNALIGNED
 }
 
 
 class FrameDescription;
 class TranslationIterator;
 class DeoptimizedFrameInfo;
 
 template<typename T>
 class HeapNumberMaterializationDescriptor BASE_EMBEDDED {
  public:
@@ skipping 925 matching lines @@
   Object** parameters_;
   Object** expression_stack_;
   int source_position_;
 
   friend class Deoptimizer;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEOPTIMIZER_H_