Address some comments

Change-Id: I0262304cc720a0e93015955d0a7fb05dfebe213e
diff --git a/compiler/image_writer.cc b/compiler/image_writer.cc
index 4ce3129..a03ff75 100644
--- a/compiler/image_writer.cc
+++ b/compiler/image_writer.cc
@@ -972,8 +972,10 @@
   size_t& offset = bin_slot_sizes_[BinTypeForNativeRelocationType(image_method_type)];
   native_object_relocations_.emplace(&image_method_array_,
                                      NativeObjectRelocation { offset, image_method_type });
-  CHECK_EQ(sizeof(image_method_array_), 8u);
-  offset += sizeof(image_method_array_);
+  const size_t array_size = LengthPrefixedArray<ArtMethod>::ComputeSize(
+      0, ArtMethod::ObjectSize(target_ptr_size_));
+  CHECK_ALIGNED(array_size, 8u);
+  offset += array_size;
   for (auto* m : image_methods_) {
     CHECK(m != nullptr);
     CHECK(m->IsRuntimeMethod());
@@ -1203,7 +1205,7 @@
     if (elem != nullptr) {
       auto it = native_object_relocations_.find(elem);
       if (it == native_object_relocations_.end()) {
-        if (true) {
+        if (it->second.IsArtMethodRelocation()) {
           auto* method = reinterpret_cast<ArtMethod*>(elem);
           LOG(FATAL) << "No relocation entry for ArtMethod " << PrettyMethod(method) << " @ "
               << method << " idx=" << i << "/" << num_elements << " with declaring class "
@@ -1300,8 +1302,8 @@
     return nullptr;
   }
   auto it = native_object_relocations_.find(obj);
-  const NativeObjectRelocation& relocation = it->second;
   CHECK(it != native_object_relocations_.end()) << obj;
+  const NativeObjectRelocation& relocation = it->second;
   return reinterpret_cast<void*>(image_begin_ + relocation.offset);
 }
 
diff --git a/compiler/image_writer.h b/compiler/image_writer.h
index eb6aa6f..f4e10cc 100644
--- a/compiler/image_writer.h
+++ b/compiler/image_writer.h
@@ -381,7 +381,8 @@
 
   // Runtime ArtMethods which aren't reachable from any Class but need to be copied into the image.
   ArtMethod* image_methods_[ImageHeader::kImageMethodsCount];
-  // Fake length prefixed array for image methods.
+  // Fake length prefixed array for image methods. This array does not contain the actual
+  // ArtMethods. We only use it for the header and relocation addresses.
   LengthPrefixedArray<ArtMethod> image_method_array_;
 
   // Counters for measurements, used for logging only.