Fix struct alignment for SIMD objects.

runtime/vm/raw_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 VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/globals.h"
@@ skipping 1978 matching lines @@
   }
 
 
   friend class SnapshotReader;
 };
 
 
 class RawFloat32x4 : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Float32x4);
 
-  float value_[4];
+  ALIGN8 float value_[4];
 
   friend class SnapshotReader;
  public:
   float x() const { return value_[0]; }
   float y() const { return value_[1]; }
   float z() const { return value_[2]; }
   float w() const { return value_[3]; }
 };
+COMPILE_ASSERT(sizeof(RawFloat32x4) == 24);
 
 
 class RawInt32x4 : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Int32x4);
 
-  int32_t value_[4];
+  ALIGN8 int32_t value_[4];
 
   friend class SnapshotReader;
  public:
   int32_t x() const { return value_[0]; }
   int32_t y() const { return value_[1]; }
   int32_t z() const { return value_[2]; }
   int32_t w() const { return value_[3]; }
 };
+COMPILE_ASSERT(sizeof(RawInt32x4) == 24);
 
 
 class RawFloat64x2 : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(Float64x2);
 
-  double value_[2];
+  ALIGN8 double value_[2];
 
   friend class SnapshotReader;
  public:
   double x() const { return value_[0]; }
   double y() const { return value_[1]; }
 };
+COMPILE_ASSERT(sizeof(RawFloat64x2) == 24);
 
 
 // Define an aliases for intptr_t.
 #if defined(ARCH_IS_32_BIT)
 #define kIntPtrCid kTypedDataInt32ArrayCid
 #define SetIntPtr SetInt32
 #elif defined(ARCH_IS_64_BIT)
 #define kIntPtrCid kTypedDataInt64ArrayCid
 #define SetIntPtr SetInt64
 #else
@@ skipping 385 matching lines @@
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_