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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_RUNTIME_UTILS_DEX_CACHE_ARRAYS_LAYOUT_INL_H_
     18 #define ART_RUNTIME_UTILS_DEX_CACHE_ARRAYS_LAYOUT_INL_H_
     19 
     20 #include "dex_cache_arrays_layout.h"
     21 
     22 #include "base/bit_utils.h"
     23 #include "base/logging.h"
     24 #include "gc_root.h"
     25 #include "globals.h"
     26 #include "primitive.h"
     27 
     28 namespace art {
     29 
     30 inline DexCacheArraysLayout::DexCacheArraysLayout(size_t pointer_size,
     31                                                   const DexFile::Header& header)
     32     : pointer_size_(pointer_size),
     33       /* types_offset_ is always 0u, so it's constexpr */
     34       methods_offset_(
     35           RoundUp(types_offset_ + TypesSize(header.type_ids_size_), MethodsAlignment())),
     36       strings_offset_(
     37           RoundUp(methods_offset_ + MethodsSize(header.method_ids_size_), StringsAlignment())),
     38       fields_offset_(
     39           RoundUp(strings_offset_ + StringsSize(header.string_ids_size_), FieldsAlignment())),
     40       size_(
     41           RoundUp(fields_offset_ + FieldsSize(header.field_ids_size_), Alignment())) {
     42   DCHECK(ValidPointerSize(pointer_size)) << pointer_size;
     43 }
     44 
     45 inline DexCacheArraysLayout::DexCacheArraysLayout(size_t pointer_size, const DexFile* dex_file)
     46     : DexCacheArraysLayout(pointer_size, dex_file->GetHeader()) {
     47 }
     48 
     49 inline size_t DexCacheArraysLayout::Alignment() const {
     50   // GcRoot<> alignment is 4, i.e. lower than or equal to the pointer alignment.
     51   static_assert(alignof(GcRoot<mirror::Class>) == 4, "Expecting alignof(GcRoot<>) == 4");
     52   static_assert(alignof(GcRoot<mirror::String>) == 4, "Expecting alignof(GcRoot<>) == 4");
     53   DCHECK(pointer_size_ == 4u || pointer_size_ == 8u);
     54   // Pointer alignment is the same as pointer size.
     55   return pointer_size_;
     56 }
     57 
     58 inline size_t DexCacheArraysLayout::TypeOffset(uint32_t type_idx) const {
     59   return types_offset_ + ElementOffset(sizeof(GcRoot<mirror::Class>), type_idx);
     60 }
     61 
     62 inline size_t DexCacheArraysLayout::TypesSize(size_t num_elements) const {
     63   // App image patching relies on having enough room for a forwarding pointer in the types array.
     64   // See FixupArtMethodArrayVisitor and ClassLinker::AddImageSpace.
     65   return std::max(ArraySize(sizeof(GcRoot<mirror::Class>), num_elements), pointer_size_);
     66 }
     67 
     68 inline size_t DexCacheArraysLayout::TypesAlignment() const {
     69   return alignof(GcRoot<mirror::Class>);
     70 }
     71 
     72 inline size_t DexCacheArraysLayout::MethodOffset(uint32_t method_idx) const {
     73   return methods_offset_ + ElementOffset(pointer_size_, method_idx);
     74 }
     75 
     76 inline size_t DexCacheArraysLayout::MethodsSize(size_t num_elements) const {
     77   // App image patching relies on having enough room for a forwarding pointer in the methods array.
     78   return std::max(ArraySize(pointer_size_, num_elements), pointer_size_);
     79 }
     80 
     81 inline size_t DexCacheArraysLayout::MethodsAlignment() const {
     82   return pointer_size_;
     83 }
     84 
     85 inline size_t DexCacheArraysLayout::StringOffset(uint32_t string_idx) const {
     86   return strings_offset_ + ElementOffset(sizeof(GcRoot<mirror::String>), string_idx);
     87 }
     88 
     89 inline size_t DexCacheArraysLayout::StringsSize(size_t num_elements) const {
     90   return ArraySize(sizeof(GcRoot<mirror::String>), num_elements);
     91 }
     92 
     93 inline size_t DexCacheArraysLayout::StringsAlignment() const {
     94   return alignof(GcRoot<mirror::String>);
     95 }
     96 
     97 inline size_t DexCacheArraysLayout::FieldOffset(uint32_t field_idx) const {
     98   return fields_offset_ + ElementOffset(pointer_size_, field_idx);
     99 }
    100 
    101 inline size_t DexCacheArraysLayout::FieldsSize(size_t num_elements) const {
    102   return ArraySize(pointer_size_, num_elements);
    103 }
    104 
    105 inline size_t DexCacheArraysLayout::FieldsAlignment() const {
    106   return pointer_size_;
    107 }
    108 
    109 inline size_t DexCacheArraysLayout::ElementOffset(size_t element_size, uint32_t idx) {
    110   return element_size * idx;
    111 }
    112 
    113 inline size_t DexCacheArraysLayout::ArraySize(size_t element_size, uint32_t num_elements) {
    114   return element_size * num_elements;
    115 }
    116 
    117 }  // namespace art
    118 
    119 #endif  // ART_RUNTIME_UTILS_DEX_CACHE_ARRAYS_LAYOUT_INL_H_
    120