Correctly pointer-align code cache payload.

src/serialize.cc

Index: src/serialize.cc
diff --git a/src/serialize.cc b/src/serialize.cc
index e2ff9f42f3d79a52c0301f43c164f4bbd91fa1a4..b8bf4205acdec8a6757d7c6a37d3232222d53648 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -2556,7 +2556,9 @@ SerializedCodeData::SerializedCodeData(const List<byte>& payload,
   int reservation_size = reservations.length() * kInt32Size;
   int num_stub_keys = stub_keys->length();
   int stub_keys_size = stub_keys->length() * kInt32Size;
-  int size = kHeaderSize + reservation_size + stub_keys_size + payload.length();
+  int payload_offset = kHeaderSize + reservation_size + stub_keys_size;
+  int padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
+  int size = kHeaderSize + padded_payload_offset + payload.length();
 
   // Allocate backing store and create result data.
   AllocateData(size);
@@ -2584,9 +2586,11 @@ SerializedCodeData::SerializedCodeData(const List<byte>& payload,
   CopyBytes(data_ + kHeaderSize + reservation_size,
             reinterpret_cast<byte*>(stub_keys->begin()), stub_keys_size);
 
+  memset(data_ + payload_offset, 0, padded_payload_offset - payload_offset);
+
   // Copy serialized data.
-  CopyBytes(data_ + kHeaderSize + reservation_size + stub_keys_size,
-            payload.begin(), static_cast<size_t>(payload.length()));
+  CopyBytes(data_ + padded_payload_offset, payload.begin(),
+            static_cast<size_t>(payload.length()));
 }
 
 
@@ -2623,8 +2627,10 @@ Vector<const SerializedData::Reservation> SerializedCodeData::Reservations()
 Vector<const byte> SerializedCodeData::Payload() const {
   int reservations_size = GetHeaderValue(kReservationsOffset) * kInt32Size;
   int code_stubs_size = GetHeaderValue(kNumCodeStubKeysOffset) * kInt32Size;
-  const byte* payload =
-      data_ + kHeaderSize + reservations_size + code_stubs_size;
+  int payload_offset = kHeaderSize + reservations_size + code_stubs_size;
+  int padded_payload_offset = POINTER_SIZE_ALIGN(payload_offset);
+  const byte* payload = data_ + padded_payload_offset;
+  DCHECK(IsAligned(reinterpret_cast<intptr_t>(payload), kPointerAlignment));
   int length = GetHeaderValue(kPayloadLengthOffset);
   DCHECK_EQ(data_ + size_, payload + length);
   return Vector<const byte>(payload, length);