Separate DexIr building from constructors.

Move all the construction from DexFile out of the constructors of the
basic IR.

Bug: 29921113
Change-Id: I3f79c104ce7183ddde73f143c047061416009a54
Test: test-art-host-gtest
diff --git a/dexlayout/dex_ir_builder.cc b/dexlayout/dex_ir_builder.cc
new file mode 100644
index 0000000..38f35e7
--- /dev/null
+++ b/dexlayout/dex_ir_builder.cc
@@ -0,0 +1,507 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Header file of an in-memory representation of DEX files.
+ */
+
+#include <stdint.h>
+#include <vector>
+
+#include "dex_ir_builder.h"
+
+namespace art {
+namespace dex_ir {
+
+namespace {
+
+static uint64_t ReadVarWidth(const uint8_t** data, uint8_t length, bool sign_extend) {
+  uint64_t value = 0;
+  for (uint32_t i = 0; i <= length; i++) {
+    value |= static_cast<uint64_t>(*(*data)++) << (i * 8);
+  }
+  if (sign_extend) {
+    int shift = (7 - length) * 8;
+    return (static_cast<int64_t>(value) << shift) >> shift;
+  }
+  return value;
+}
+
+// Prototype to break cyclic dependency.
+void ReadPayloadUnion(Header& header,
+                      const uint8_t** data,
+                      uint8_t type,
+                      uint8_t length,
+                      ArrayItem::PayloadUnion* item);
+
+ArrayItem* ReadArrayItem(Header& header, const uint8_t** data, uint8_t type, uint8_t length) {
+  ArrayItem* item = new ArrayItem(type);
+  ReadPayloadUnion(header, data, type, length, item->GetPayloadUnion());
+  return item;
+}
+
+ArrayItem* ReadArrayItem(Header& header, const uint8_t** data) {
+  const uint8_t encoded_value = *(*data)++;
+  const uint8_t type = encoded_value & 0x1f;
+  ArrayItem* item = new ArrayItem(type);
+  ReadPayloadUnion(header, data, type, encoded_value >> 5, item->GetPayloadUnion());
+  return item;
+}
+
+void ReadPayloadUnion(Header& header,
+                      const uint8_t** data,
+                      uint8_t type,
+                      uint8_t length,
+                      ArrayItem::PayloadUnion* item) {
+  switch (type) {
+    case DexFile::kDexAnnotationByte:
+      item->byte_val_ = static_cast<int8_t>(ReadVarWidth(data, length, false));
+      break;
+    case DexFile::kDexAnnotationShort:
+      item->short_val_ = static_cast<int16_t>(ReadVarWidth(data, length, true));
+      break;
+    case DexFile::kDexAnnotationChar:
+      item->char_val_ = static_cast<uint16_t>(ReadVarWidth(data, length, false));
+      break;
+    case DexFile::kDexAnnotationInt:
+      item->int_val_ = static_cast<int32_t>(ReadVarWidth(data, length, true));
+      break;
+    case DexFile::kDexAnnotationLong:
+      item->long_val_ = static_cast<int64_t>(ReadVarWidth(data, length, true));
+      break;
+    case DexFile::kDexAnnotationFloat: {
+      // Fill on right.
+      union {
+        float f;
+        uint32_t data;
+      } conv;
+      conv.data = static_cast<uint32_t>(ReadVarWidth(data, length, false)) << (3 - length) * 8;
+      item->float_val_ = conv.f;
+      break;
+    }
+    case DexFile::kDexAnnotationDouble: {
+      // Fill on right.
+      union {
+        double d;
+        uint64_t data;
+      } conv;
+      conv.data = ReadVarWidth(data, length, false) << (7 - length) * 8;
+      item->double_val_ = conv.d;
+      break;
+    }
+    case DexFile::kDexAnnotationString: {
+      const uint32_t string_index = static_cast<uint32_t>(ReadVarWidth(data, length, false));
+      item->string_val_ = header.StringIds()[string_index].get();
+      break;
+    }
+    case DexFile::kDexAnnotationType: {
+      const uint32_t string_index = static_cast<uint32_t>(ReadVarWidth(data, length, false));
+      item->string_val_ = header.TypeIds()[string_index]->GetStringId();
+      break;
+    }
+    case DexFile::kDexAnnotationField:
+    case DexFile::kDexAnnotationEnum: {
+      const uint32_t field_index = static_cast<uint32_t>(ReadVarWidth(data, length, false));
+      item->field_val_ = header.FieldIds()[field_index].get();
+      break;
+    }
+    case DexFile::kDexAnnotationMethod: {
+      const uint32_t method_index = static_cast<uint32_t>(ReadVarWidth(data, length, false));
+      item->method_val_ = header.MethodIds()[method_index].get();
+      break;
+    }
+    case DexFile::kDexAnnotationArray: {
+      item->annotation_array_val_ = new ArrayItemVector();
+      // Decode all elements.
+      const uint32_t size = DecodeUnsignedLeb128(data);
+      for (uint32_t i = 0; i < size; i++) {
+        item->annotation_array_val_->push_back(
+            std::unique_ptr<ArrayItem>(ReadArrayItem(header, data)));
+      }
+      break;
+    }
+    case DexFile::kDexAnnotationAnnotation: {
+      const uint32_t type_idx = DecodeUnsignedLeb128(data);
+      item->annotation_annotation_val_.string_ = header.TypeIds()[type_idx]->GetStringId();
+      item->annotation_annotation_val_.array_ =
+          new std::vector<std::unique_ptr<ArrayItem::NameValuePair>>();
+      // Decode all name=value pairs.
+      const uint32_t size = DecodeUnsignedLeb128(data);
+      for (uint32_t i = 0; i < size; i++) {
+        const uint32_t name_index = DecodeUnsignedLeb128(data);
+        item->annotation_annotation_val_.array_->push_back(
+            std::unique_ptr<ArrayItem::NameValuePair>(
+                new ArrayItem::NameValuePair(header.StringIds()[name_index].get(),
+                                             ReadArrayItem(header, data))));
+      }
+      break;
+    }
+    case DexFile::kDexAnnotationNull:
+      break;
+    case DexFile::kDexAnnotationBoolean:
+      item->bool_val_ = (length != 0);
+      break;
+    default:
+      break;
+  }
+}
+
+static bool GetPositionsCb(void* context, const DexFile::PositionInfo& entry) {
+  DebugInfoItem* debug_info = reinterpret_cast<DebugInfoItem*>(context);
+  PositionInfoVector& positions = debug_info->GetPositionInfo();
+  positions.push_back(std::unique_ptr<PositionInfo>(new PositionInfo(entry.address_, entry.line_)));
+  return false;
+}
+
+static void GetLocalsCb(void* context, const DexFile::LocalInfo& entry) {
+  DebugInfoItem* debug_info = reinterpret_cast<DebugInfoItem*>(context);
+  LocalInfoVector& locals = debug_info->GetLocalInfo();
+  const char* name = entry.name_ != nullptr ? entry.name_ : "(null)";
+  const char* signature = entry.signature_ != nullptr ? entry.signature_ : "";
+  locals.push_back(std::unique_ptr<LocalInfo>(
+      new LocalInfo(name, entry.descriptor_, signature, entry.start_address_,
+                    entry.end_address_, entry.reg_)));
+}
+
+CodeItem* ReadCodeItem(const DexFile& dex_file,
+                       const DexFile::CodeItem& disk_code_item,
+                       Header& header) {
+  uint16_t registers_size = disk_code_item.registers_size_;
+  uint16_t ins_size = disk_code_item.ins_size_;
+  uint16_t outs_size = disk_code_item.outs_size_;
+  uint32_t tries_size = disk_code_item.tries_size_;
+
+  const uint8_t* debug_info_stream = dex_file.GetDebugInfoStream(&disk_code_item);
+  DebugInfoItem* debug_info = nullptr;
+  if (debug_info_stream != nullptr) {
+    debug_info = new DebugInfoItem();
+  }
+
+  uint32_t insns_size = disk_code_item.insns_size_in_code_units_;
+  uint16_t* insns = new uint16_t[insns_size];
+  memcpy(insns, disk_code_item.insns_, insns_size * sizeof(uint16_t));
+
+  TryItemVector* tries = nullptr;
+  if (tries_size > 0) {
+    tries = new TryItemVector();
+    for (uint32_t i = 0; i < tries_size; ++i) {
+      const DexFile::TryItem* disk_try_item = dex_file.GetTryItems(disk_code_item, i);
+      uint32_t start_addr = disk_try_item->start_addr_;
+      uint16_t insn_count = disk_try_item->insn_count_;
+      CatchHandlerVector* handlers = new CatchHandlerVector();
+      for (CatchHandlerIterator it(disk_code_item, *disk_try_item); it.HasNext(); it.Next()) {
+        const uint16_t type_index = it.GetHandlerTypeIndex();
+        const TypeId* type_id = header.GetTypeIdOrNullPtr(type_index);
+        handlers->push_back(std::unique_ptr<const CatchHandler>(
+            new CatchHandler(type_id, it.GetHandlerAddress())));
+      }
+      TryItem* try_item = new TryItem(start_addr, insn_count, handlers);
+      tries->push_back(std::unique_ptr<const TryItem>(try_item));
+    }
+  }
+  return new CodeItem(registers_size, ins_size, outs_size, debug_info, insns_size, insns, tries);
+}
+
+MethodItem* GenerateMethodItem(const DexFile& dex_file,
+                               dex_ir::Header& header,
+                               ClassDataItemIterator& cdii) {
+  MethodId* method_item = header.MethodIds()[cdii.GetMemberIndex()].get();
+  uint32_t access_flags = cdii.GetRawMemberAccessFlags();
+  const DexFile::CodeItem* disk_code_item = cdii.GetMethodCodeItem();
+  CodeItem* code_item = nullptr;
+  DebugInfoItem* debug_info = nullptr;
+  if (disk_code_item != nullptr) {
+    code_item = ReadCodeItem(dex_file, *disk_code_item, header);
+    code_item->SetOffset(cdii.GetMethodCodeItemOffset());
+    debug_info = code_item->DebugInfo();
+  }
+  if (debug_info != nullptr) {
+    bool is_static = (access_flags & kAccStatic) != 0;
+    dex_file.DecodeDebugLocalInfo(
+        disk_code_item, is_static, cdii.GetMemberIndex(), GetLocalsCb, debug_info);
+    dex_file.DecodeDebugPositionInfo(disk_code_item, GetPositionsCb, debug_info);
+  }
+  return new MethodItem(access_flags, method_item, code_item);
+}
+
+AnnotationSetItem* ReadAnnotationSetItem(const DexFile& dex_file,
+                                         const DexFile::AnnotationSetItem& disk_annotations_item,
+                                         Header& header) {
+  if (disk_annotations_item.size_ == 0) {
+    return nullptr;
+  }
+  AnnotationItemVector* items = new AnnotationItemVector();
+  for (uint32_t i = 0; i < disk_annotations_item.size_; ++i) {
+    const DexFile::AnnotationItem* annotation =
+        dex_file.GetAnnotationItem(&disk_annotations_item, i);
+    if (annotation == nullptr) {
+      continue;
+    }
+    uint8_t visibility = annotation->visibility_;
+    const uint8_t* annotation_data = annotation->annotation_;
+    ArrayItem* array_item =
+        ReadArrayItem(header, &annotation_data, DexFile::kDexAnnotationAnnotation, 0);
+    items->push_back(std::unique_ptr<AnnotationItem>(new AnnotationItem(visibility, array_item)));
+  }
+  return new AnnotationSetItem(items);
+}
+
+ParameterAnnotation* ReadParameterAnnotation(
+    const DexFile& dex_file,
+    MethodId* method_id,
+    const DexFile::AnnotationSetRefList* annotation_set_ref_list,
+    Header& header) {
+  AnnotationSetItemVector* annotations = new AnnotationSetItemVector();
+  for (uint32_t i = 0; i < annotation_set_ref_list->size_; ++i) {
+    const DexFile::AnnotationSetItem* annotation_set_item =
+        dex_file.GetSetRefItemItem(&annotation_set_ref_list->list_[i]);
+    annotations->push_back(std::unique_ptr<AnnotationSetItem>(
+        ReadAnnotationSetItem(dex_file, *annotation_set_item, header)));
+  }
+  return new ParameterAnnotation(method_id, annotations);
+}
+
+AnnotationsDirectoryItem* ReadAnnotationsDirectoryItem(
+    const DexFile& dex_file,
+    const DexFile::AnnotationsDirectoryItem* disk_annotations_item,
+    Header& header) {
+  const DexFile::AnnotationSetItem* class_set_item =
+      dex_file.GetClassAnnotationSet(disk_annotations_item);
+  AnnotationSetItem* class_annotation = nullptr;
+  if (class_set_item != nullptr) {
+    class_annotation = ReadAnnotationSetItem(dex_file, *class_set_item, header);
+  }
+  const DexFile::FieldAnnotationsItem* fields =
+      dex_file.GetFieldAnnotations(disk_annotations_item);
+  FieldAnnotationVector* field_annotations = nullptr;
+  if (fields != nullptr) {
+    field_annotations = new FieldAnnotationVector();
+    for (uint32_t i = 0; i < disk_annotations_item->fields_size_; ++i) {
+      FieldId* field_id = header.FieldIds()[fields[i].field_idx_].get();
+      const DexFile::AnnotationSetItem* field_set_item =
+          dex_file.GetFieldAnnotationSetItem(fields[i]);
+      AnnotationSetItem* annotation_set_item =
+          ReadAnnotationSetItem(dex_file, *field_set_item, header);
+      field_annotations->push_back(std::unique_ptr<FieldAnnotation>(
+          new FieldAnnotation(field_id, annotation_set_item)));
+    }
+  }
+  const DexFile::MethodAnnotationsItem* methods =
+      dex_file.GetMethodAnnotations(disk_annotations_item);
+  MethodAnnotationVector* method_annotations = nullptr;
+  if (methods != nullptr) {
+    method_annotations = new MethodAnnotationVector();
+    for (uint32_t i = 0; i < disk_annotations_item->methods_size_; ++i) {
+      MethodId* method_id = header.MethodIds()[methods[i].method_idx_].get();
+      const DexFile::AnnotationSetItem* method_set_item =
+          dex_file.GetMethodAnnotationSetItem(methods[i]);
+      AnnotationSetItem* annotation_set_item =
+          ReadAnnotationSetItem(dex_file, *method_set_item, header);
+      method_annotations->push_back(std::unique_ptr<MethodAnnotation>(
+          new MethodAnnotation(method_id, annotation_set_item)));
+    }
+  }
+  const DexFile::ParameterAnnotationsItem* parameters =
+      dex_file.GetParameterAnnotations(disk_annotations_item);
+  ParameterAnnotationVector* parameter_annotations = nullptr;
+  if (parameters != nullptr) {
+    parameter_annotations = new ParameterAnnotationVector();
+    for (uint32_t i = 0; i < disk_annotations_item->parameters_size_; ++i) {
+      MethodId* method_id = header.MethodIds()[parameters[i].method_idx_].get();
+      const DexFile::AnnotationSetRefList* list =
+          dex_file.GetParameterAnnotationSetRefList(&parameters[i]);
+      parameter_annotations->push_back(std::unique_ptr<ParameterAnnotation>(
+          ReadParameterAnnotation(dex_file, method_id, list, header)));
+    }
+  }
+
+  return new AnnotationsDirectoryItem(class_annotation,
+                                      field_annotations,
+                                      method_annotations,
+                                      parameter_annotations);
+}
+
+ClassDef* ReadClassDef(const DexFile& dex_file,
+                       const DexFile::ClassDef& disk_class_def,
+                       Header& header) {
+  const TypeId* class_type = header.TypeIds()[disk_class_def.class_idx_].get();
+  uint32_t access_flags = disk_class_def.access_flags_;
+  const TypeId* superclass = header.GetTypeIdOrNullPtr(disk_class_def.superclass_idx_);
+
+  TypeIdVector* interfaces = nullptr;
+  const DexFile::TypeList* type_list = dex_file.GetInterfacesList(disk_class_def);
+  uint32_t interfaces_offset = disk_class_def.interfaces_off_;
+  if (type_list != nullptr) {
+    interfaces = new TypeIdVector();
+    for (uint32_t index = 0; index < type_list->Size(); ++index) {
+      interfaces->push_back(header.TypeIds()[type_list->GetTypeItem(index).type_idx_].get());
+    }
+  }
+  const StringId* source_file = header.GetStringIdOrNullPtr(disk_class_def.source_file_idx_);
+  // Annotations.
+  AnnotationsDirectoryItem* annotations = nullptr;
+  const DexFile::AnnotationsDirectoryItem* disk_annotations_directory_item =
+      dex_file.GetAnnotationsDirectory(disk_class_def);
+  if (disk_annotations_directory_item != nullptr) {
+    annotations = ReadAnnotationsDirectoryItem(dex_file, disk_annotations_directory_item, header);
+    annotations->SetOffset(disk_class_def.annotations_off_);
+  }
+  // Static field initializers.
+  ArrayItemVector* static_values = nullptr;
+  const uint8_t* static_data = dex_file.GetEncodedStaticFieldValuesArray(disk_class_def);
+  if (static_data != nullptr) {
+    uint32_t static_value_count = static_data == nullptr ? 0 : DecodeUnsignedLeb128(&static_data);
+    if (static_value_count > 0) {
+      static_values = new ArrayItemVector();
+      for (uint32_t i = 0; i < static_value_count; ++i) {
+        static_values->push_back(std::unique_ptr<ArrayItem>(ReadArrayItem(header, &static_data)));
+      }
+    }
+  }
+  // Read the fields and methods defined by the class, resolving the circular reference from those
+  // to classes by setting class at the same time.
+  const uint8_t* encoded_data = dex_file.GetClassData(disk_class_def);
+  ClassData* class_data = nullptr;
+  if (encoded_data != nullptr) {
+    uint32_t offset = disk_class_def.class_data_off_;
+    ClassDataItemIterator cdii(dex_file, encoded_data);
+    // Static fields.
+    FieldItemVector* static_fields = new FieldItemVector();
+    for (uint32_t i = 0; cdii.HasNextStaticField(); i++, cdii.Next()) {
+      FieldId* field_item = header.FieldIds()[cdii.GetMemberIndex()].get();
+      uint32_t access_flags = cdii.GetRawMemberAccessFlags();
+      static_fields->push_back(std::unique_ptr<FieldItem>(new FieldItem(access_flags, field_item)));
+    }
+    // Instance fields.
+    FieldItemVector* instance_fields = new FieldItemVector();
+    for (uint32_t i = 0; cdii.HasNextInstanceField(); i++, cdii.Next()) {
+      FieldId* field_item = header.FieldIds()[cdii.GetMemberIndex()].get();
+      uint32_t access_flags = cdii.GetRawMemberAccessFlags();
+      instance_fields->push_back(
+          std::unique_ptr<FieldItem>(new FieldItem(access_flags, field_item)));
+    }
+    // Direct methods.
+    MethodItemVector* direct_methods = new MethodItemVector();
+    for (uint32_t i = 0; cdii.HasNextDirectMethod(); i++, cdii.Next()) {
+      direct_methods->push_back(
+          std::unique_ptr<MethodItem>(GenerateMethodItem(dex_file, header, cdii)));
+    }
+    // Virtual methods.
+    MethodItemVector* virtual_methods = new MethodItemVector();
+    for (uint32_t i = 0; cdii.HasNextVirtualMethod(); i++, cdii.Next()) {
+      virtual_methods->push_back(
+          std::unique_ptr<MethodItem>(GenerateMethodItem(dex_file, header, cdii)));
+    }
+    class_data = new ClassData(static_fields, instance_fields, direct_methods, virtual_methods);
+    class_data->SetOffset(offset);
+  }
+  return new ClassDef(class_type,
+                      access_flags,
+                      superclass,
+                      interfaces,
+                      interfaces_offset,
+                      source_file,
+                      annotations,
+                      static_values,
+                      class_data);
+}
+
+}  // namespace
+
+Header* DexIrBuilder(const DexFile& dex_file) {
+  const DexFile::Header& disk_header = dex_file.GetHeader();
+  Header* header = new Header(disk_header.magic_,
+                              disk_header.checksum_,
+                              disk_header.signature_,
+                              disk_header.endian_tag_,
+                              disk_header.file_size_,
+                              disk_header.header_size_,
+                              disk_header.link_size_,
+                              disk_header.link_off_,
+                              disk_header.data_size_,
+                              disk_header.data_off_);
+  // Walk the rest of the header fields.
+  // StringId table.
+  std::vector<std::unique_ptr<StringId>>& string_ids = header->StringIds();
+  header->SetStringIdsOffset(disk_header.string_ids_off_);
+  for (uint32_t i = 0; i < dex_file.NumStringIds(); ++i) {
+    const DexFile::StringId& disk_string_id = dex_file.GetStringId(i);
+    StringId* string_id = new StringId(dex_file.GetStringData(disk_string_id));
+    string_id->SetOffset(i);
+    string_ids.push_back(std::unique_ptr<StringId>(string_id));
+  }
+  // TypeId table.
+  std::vector<std::unique_ptr<TypeId>>& type_ids = header->TypeIds();
+  header->SetTypeIdsOffset(disk_header.type_ids_off_);
+  for (uint32_t i = 0; i < dex_file.NumTypeIds(); ++i) {
+    const DexFile::TypeId& disk_type_id = dex_file.GetTypeId(i);
+    TypeId* type_id = new TypeId(header->StringIds()[disk_type_id.descriptor_idx_].get());
+    type_id->SetOffset(i);
+    type_ids.push_back(std::unique_ptr<TypeId>(type_id));
+  }
+  // ProtoId table.
+  std::vector<std::unique_ptr<ProtoId>>& proto_ids = header->ProtoIds();
+  header->SetProtoIdsOffset(disk_header.proto_ids_off_);
+  for (uint32_t i = 0; i < dex_file.NumProtoIds(); ++i) {
+    const DexFile::ProtoId& disk_proto_id = dex_file.GetProtoId(i);
+    // Build the parameter type vector.
+    TypeIdVector* parameters = new TypeIdVector();
+    DexFileParameterIterator dfpi(dex_file, disk_proto_id);
+    while (dfpi.HasNext()) {
+      parameters->push_back(header->TypeIds()[dfpi.GetTypeIdx()].get());
+      dfpi.Next();
+    }
+    ProtoId* proto_id = new ProtoId(header->StringIds()[disk_proto_id.shorty_idx_].get(),
+                                    header->TypeIds()[disk_proto_id.return_type_idx_].get(),
+                                    parameters);
+    proto_id->SetOffset(i);
+    proto_ids.push_back(std::unique_ptr<ProtoId>(proto_id));
+  }
+  // FieldId table.
+  std::vector<std::unique_ptr<FieldId>>& field_ids = header->FieldIds();
+  header->SetFieldIdsOffset(disk_header.field_ids_off_);
+  for (uint32_t i = 0; i < dex_file.NumFieldIds(); ++i) {
+    const DexFile::FieldId& disk_field_id = dex_file.GetFieldId(i);
+    FieldId* field_id = new FieldId(header->TypeIds()[disk_field_id.class_idx_].get(),
+                                    header->TypeIds()[disk_field_id.type_idx_].get(),
+                                    header->StringIds()[disk_field_id.name_idx_].get());
+    field_id->SetOffset(i);
+    field_ids.push_back(std::unique_ptr<FieldId>(field_id));
+  }
+  // MethodId table.
+  std::vector<std::unique_ptr<MethodId>>& method_ids = header->MethodIds();
+  header->SetMethodIdsOffset(disk_header.method_ids_off_);
+  for (uint32_t i = 0; i < dex_file.NumMethodIds(); ++i) {
+    const DexFile::MethodId& disk_method_id = dex_file.GetMethodId(i);
+    MethodId* method_id = new MethodId(header->TypeIds()[disk_method_id.class_idx_].get(),
+                                       header->ProtoIds()[disk_method_id.proto_idx_].get(),
+                                       header->StringIds()[disk_method_id.name_idx_].get());
+    method_id->SetOffset(i);
+    method_ids.push_back(std::unique_ptr<MethodId>(method_id));
+  }
+  // ClassDef table.
+  std::vector<std::unique_ptr<ClassDef>>& class_defs = header->ClassDefs();
+  header->SetClassDefsOffset(disk_header.class_defs_off_);
+  for (uint32_t i = 0; i < dex_file.NumClassDefs(); ++i) {
+    const DexFile::ClassDef& disk_class_def = dex_file.GetClassDef(i);
+    ClassDef* class_def = ReadClassDef(dex_file, disk_class_def, *header);
+    class_def->SetOffset(i);
+    class_defs.push_back(std::unique_ptr<ClassDef>(class_def));
+  }
+
+  return header;
+}
+
+}  // namespace dex_ir
+}  // namespace art