Fix unaligned access to TypedData from native code.

runtime/vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_OBJECT_H_
 #define RUNTIME_VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 7915 matching lines @@
     return reinterpret_cast<void*>(
         UnsafeMutableNonPointer(raw_ptr()->data()) + byte_offset);
   }
 
   virtual bool CanonicalizeEquals(const Instance& other) const;
   virtual uword ComputeCanonicalTableHash() const;
 
 #define TYPED_GETTER_SETTER(name, type)                                        \
   type Get##name(intptr_t byte_offset) const {                                 \
     NoSafepointScope no_safepoint;                                             \
-    return *reinterpret_cast<type*>(DataAddr(byte_offset));                    \
+    type result;                                                               \
+    memmove(&result, DataAddr(byte_offset), sizeof(type));                     \

[zra, 2016/11/01 21:46:01]

Should we specialize this by architecture?

[Cutch, 2016/11/01 21:48:21]

+1 We should avoid calling memmove on architectures that don't need it.

+    return result;                                                             \
   }                                                                            \
   void Set##name(intptr_t byte_offset, type value) const {                     \
     NoSafepointScope no_safepoint;                                             \
-    *reinterpret_cast<type*>(DataAddr(byte_offset)) = value;                   \
+    memmove(DataAddr(byte_offset), &value, sizeof(type));                      \
   }
   TYPED_GETTER_SETTER(Int8, int8_t)
   TYPED_GETTER_SETTER(Uint8, uint8_t)
   TYPED_GETTER_SETTER(Int16, int16_t)
   TYPED_GETTER_SETTER(Uint16, uint16_t)
   TYPED_GETTER_SETTER(Int32, int32_t)
   TYPED_GETTER_SETTER(Uint32, uint32_t)
   TYPED_GETTER_SETTER(Int64, int64_t)
   TYPED_GETTER_SETTER(Uint64, uint64_t)
   TYPED_GETTER_SETTER(Float32, float)
@@ skipping 1060 matching lines @@
 
 inline void TypeArguments::SetHash(intptr_t value) const {
   // This is only safe because we create a new Smi, which does not cause
   // heap allocation.
   StoreSmi(&raw_ptr()->hash_, Smi::New(value));
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_OBJECT_H_