compiler/optimizing/stack_map_stream.cc - platform/art - Gitiles

 /*
  * Copyright (C) 2015 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.
  */
 #include "stack_map_stream.h"

 namespace art {

 void StackMapStream::BeginStackMapEntry(uint32_t dex_pc,
                                         uint32_t native_pc_offset,
                                         uint32_t register_mask,
                                         BitVector* sp_mask,
                                         uint32_t num_dex_registers,
                                         uint8_t inlining_depth) {
   DCHECK_EQ(0u, current_entry_.dex_pc) << "EndStackMapEntry not called after BeginStackMapEntry";
   current_entry_.dex_pc = dex_pc;
   current_entry_.native_pc_offset = native_pc_offset;
   current_entry_.register_mask = register_mask;
   current_entry_.sp_mask = sp_mask;
   current_entry_.num_dex_registers = num_dex_registers;
   current_entry_.inlining_depth = inlining_depth;
   current_entry_.dex_register_locations_start_index = dex_register_locations_.Size();
   current_entry_.inline_infos_start_index = inline_infos_.Size();
   current_entry_.dex_register_map_hash = 0;
   current_entry_.same_dex_register_map_as_ = kNoSameDexMapFound;
   if (num_dex_registers != 0) {
     current_entry_.live_dex_registers_mask =
         new (allocator_) ArenaBitVector(allocator_, num_dex_registers, true);
   } else {
     current_entry_.live_dex_registers_mask = nullptr;
   }

   if (sp_mask != nullptr) {
     stack_mask_max_ = std::max(stack_mask_max_, sp_mask->GetHighestBitSet());
   }
   if (inlining_depth > 0) {
     number_of_stack_maps_with_inline_info_++;
   }

   dex_pc_max_ = std::max(dex_pc_max_, dex_pc);
   register_mask_max_ = std::max(register_mask_max_, register_mask);
   current_dex_register_ = 0;
 }

 void StackMapStream::EndStackMapEntry() {
   current_entry_.same_dex_register_map_as_ = FindEntryWithTheSameDexMap();
   stack_maps_.Add(current_entry_);
   current_entry_ = StackMapEntry();
 }

 void StackMapStream::AddDexRegisterEntry(DexRegisterLocation::Kind kind, int32_t value) {
   if (kind != DexRegisterLocation::Kind::kNone) {
     // Ensure we only use non-compressed location kind at this stage.
     DCHECK(DexRegisterLocation::IsShortLocationKind(kind))
         << DexRegisterLocation::PrettyDescriptor(kind);
     DexRegisterLocation location(kind, value);

     // Look for Dex register `location` in the location catalog (using the
     // companion hash map of locations to indices).  Use its index if it
     // is already in the location catalog.  If not, insert it (in the
     // location catalog and the hash map) and use the newly created index.
     auto it = location_catalog_entries_indices_.Find(location);
     if (it != location_catalog_entries_indices_.end()) {
       // Retrieve the index from the hash map.
       dex_register_locations_.Add(it->second);
     } else {
       // Create a new entry in the location catalog and the hash map.
       size_t index = location_catalog_entries_.Size();
       location_catalog_entries_.Add(location);
       dex_register_locations_.Add(index);
       location_catalog_entries_indices_.Insert(std::make_pair(location, index));
     }

     if (in_inline_frame_) {
       // TODO: Support sharing DexRegisterMap across InlineInfo.
       DCHECK_LT(current_dex_register_, current_inline_info_.num_dex_registers);
       current_inline_info_.live_dex_registers_mask->SetBit(current_dex_register_);
     } else {
       DCHECK_LT(current_dex_register_, current_entry_.num_dex_registers);
       current_entry_.live_dex_registers_mask->SetBit(current_dex_register_);
       current_entry_.dex_register_map_hash += (1 <<
           (current_dex_register_ % (sizeof(current_entry_.dex_register_map_hash) * kBitsPerByte)));
       current_entry_.dex_register_map_hash += static_cast<uint32_t>(value);
       current_entry_.dex_register_map_hash += static_cast<uint32_t>(kind);
     }
   }
   current_dex_register_++;
 }

 void StackMapStream::BeginInlineInfoEntry(uint32_t method_index,
                                           uint32_t dex_pc,
                                           InvokeType invoke_type,
                                           uint32_t num_dex_registers) {
   DCHECK(!in_inline_frame_);
   in_inline_frame_ = true;
   current_inline_info_.method_index = method_index;
   current_inline_info_.dex_pc = dex_pc;
   current_inline_info_.invoke_type = invoke_type;
   current_inline_info_.num_dex_registers = num_dex_registers;
   current_inline_info_.dex_register_locations_start_index = dex_register_locations_.Size();
   if (num_dex_registers != 0) {
     current_inline_info_.live_dex_registers_mask =
         new (allocator_) ArenaBitVector(allocator_, num_dex_registers, true);
   } else {
     current_inline_info_.live_dex_registers_mask = nullptr;
   }
   current_dex_register_ = 0;
 }

 void StackMapStream::EndInlineInfoEntry() {
   DCHECK(in_inline_frame_);
   DCHECK_EQ(current_dex_register_, current_inline_info_.num_dex_registers)
       << "Inline information contains less registers than expected";
   in_inline_frame_ = false;
   inline_infos_.Add(current_inline_info_);
   current_inline_info_ = InlineInfoEntry();
 }

 uint32_t StackMapStream::ComputeMaxNativePcOffset() const {
   uint32_t max_native_pc_offset = 0u;
   for (size_t i = 0, size = stack_maps_.Size(); i != size; ++i) {
     max_native_pc_offset = std::max(max_native_pc_offset, stack_maps_.Get(i).native_pc_offset);
   }
   return max_native_pc_offset;
 }

 size_t StackMapStream::PrepareForFillIn() {
   int stack_mask_number_of_bits = stack_mask_max_ + 1;  // Need room for max element too.
   stack_mask_size_ = RoundUp(stack_mask_number_of_bits, kBitsPerByte) / kBitsPerByte;
   inline_info_size_ = ComputeInlineInfoSize();
   dex_register_maps_size_ = ComputeDexRegisterMapsSize();
   uint32_t max_native_pc_offset = ComputeMaxNativePcOffset();
   stack_map_encoding_ = StackMapEncoding::CreateFromSizes(stack_mask_size_,
                                                           inline_info_size_,
                                                           dex_register_maps_size_,
                                                           dex_pc_max_,
                                                           max_native_pc_offset,
                                                           register_mask_max_);
   stack_maps_size_ = stack_maps_.Size() * stack_map_encoding_.ComputeStackMapSize();
   dex_register_location_catalog_size_ = ComputeDexRegisterLocationCatalogSize();

   // Note: use RoundUp to word-size here if you want CodeInfo objects to be word aligned.
   needed_size_ = CodeInfo::kFixedSize
       + stack_maps_size_
       + dex_register_location_catalog_size_
       + dex_register_maps_size_
       + inline_info_size_;

   stack_maps_start_ = CodeInfo::kFixedSize;
   // TODO: Move the catalog at the end. It is currently too expensive at runtime
   // to compute its size (note that we do not encode that size in the CodeInfo).
   dex_register_location_catalog_start_ = stack_maps_start_ + stack_maps_size_;
   dex_register_maps_start_ =
       dex_register_location_catalog_start_ + dex_register_location_catalog_size_;
   inline_infos_start_ = dex_register_maps_start_ + dex_register_maps_size_;

   return needed_size_;
 }

 size_t StackMapStream::ComputeDexRegisterLocationCatalogSize() const {
   size_t size = DexRegisterLocationCatalog::kFixedSize;
   for (size_t location_catalog_entry_index = 0;
        location_catalog_entry_index < location_catalog_entries_.Size();
        ++location_catalog_entry_index) {
     DexRegisterLocation dex_register_location =
         location_catalog_entries_.Get(location_catalog_entry_index);
     size += DexRegisterLocationCatalog::EntrySize(dex_register_location);
   }
   return size;
 }

 size_t StackMapStream::ComputeDexRegisterMapSize(uint32_t num_dex_registers,
                                                  const BitVector& live_dex_registers_mask) const {
   // Size of the map in bytes.
   size_t size = DexRegisterMap::kFixedSize;
   // Add the live bit mask for the Dex register liveness.
   size += DexRegisterMap::GetLiveBitMaskSize(num_dex_registers);
   // Compute the size of the set of live Dex register entries.
   size_t number_of_live_dex_registers = 0;
   for (size_t dex_register_number = 0;
        dex_register_number < num_dex_registers;
        ++dex_register_number) {
     if (live_dex_registers_mask.IsBitSet(dex_register_number)) {
       ++number_of_live_dex_registers;
     }
   }
   size_t map_entries_size_in_bits =
       DexRegisterMap::SingleEntrySizeInBits(location_catalog_entries_.Size())
       * number_of_live_dex_registers;
   size_t map_entries_size_in_bytes =
       RoundUp(map_entries_size_in_bits, kBitsPerByte) / kBitsPerByte;
   size += map_entries_size_in_bytes;
   return size;
 }

 size_t StackMapStream::ComputeDexRegisterMapsSize() const {
   size_t size = 0;
   size_t inline_info_index = 0;
   for (size_t i = 0; i < stack_maps_.Size(); ++i) {
     StackMapEntry entry = stack_maps_.Get(i);
     if (entry.same_dex_register_map_as_ == kNoSameDexMapFound) {
       size += ComputeDexRegisterMapSize(entry.num_dex_registers, *entry.live_dex_registers_mask);
     } else {
       // Entries with the same dex map will have the same offset.
     }
     for (size_t j = 0; j < entry.inlining_depth; ++j) {
       InlineInfoEntry inline_entry = inline_infos_.Get(inline_info_index++);
       size += ComputeDexRegisterMapSize(inline_entry.num_dex_registers,
                                         *inline_entry.live_dex_registers_mask);
     }
   }
   return size;
 }

 size_t StackMapStream::ComputeInlineInfoSize() const {
   return inline_infos_.Size() * InlineInfo::SingleEntrySize()
     // For encoding the depth.
     + (number_of_stack_maps_with_inline_info_ * InlineInfo::kFixedSize);
 }

 void StackMapStream::FillIn(MemoryRegion region) {
   DCHECK_EQ(0u, current_entry_.dex_pc) << "EndStackMapEntry not called after BeginStackMapEntry";
   DCHECK_NE(0u, needed_size_) << "PrepareForFillIn not called before FillIn";

   CodeInfo code_info(region);
   DCHECK_EQ(region.size(), needed_size_);
   code_info.SetOverallSize(region.size());

   MemoryRegion dex_register_locations_region = region.Subregion(
       dex_register_maps_start_, dex_register_maps_size_);

   MemoryRegion inline_infos_region = region.Subregion(
       inline_infos_start_, inline_info_size_);

   code_info.SetEncoding(stack_map_encoding_);
   code_info.SetNumberOfStackMaps(stack_maps_.Size());
   DCHECK_EQ(code_info.GetStackMapsSize(code_info.ExtractEncoding()), stack_maps_size_);

   // Set the Dex register location catalog.
   code_info.SetNumberOfLocationCatalogEntries(location_catalog_entries_.Size());
   MemoryRegion dex_register_location_catalog_region = region.Subregion(
       dex_register_location_catalog_start_, dex_register_location_catalog_size_);
   DexRegisterLocationCatalog dex_register_location_catalog(dex_register_location_catalog_region);
   // Offset in `dex_register_location_catalog` where to store the next
   // register location.
   size_t location_catalog_offset = DexRegisterLocationCatalog::kFixedSize;
   for (size_t i = 0, e = location_catalog_entries_.Size(); i < e; ++i) {
     DexRegisterLocation dex_register_location = location_catalog_entries_.Get(i);
     dex_register_location_catalog.SetRegisterInfo(location_catalog_offset, dex_register_location);
     location_catalog_offset += DexRegisterLocationCatalog::EntrySize(dex_register_location);
   }
   // Ensure we reached the end of the Dex registers location_catalog.
   DCHECK_EQ(location_catalog_offset, dex_register_location_catalog_region.size());

   uintptr_t next_dex_register_map_offset = 0;
   uintptr_t next_inline_info_offset = 0;
   for (size_t i = 0, e = stack_maps_.Size(); i < e; ++i) {
     StackMap stack_map = code_info.GetStackMapAt(i, stack_map_encoding_);
     StackMapEntry entry = stack_maps_.Get(i);

     stack_map.SetDexPc(stack_map_encoding_, entry.dex_pc);
     stack_map.SetNativePcOffset(stack_map_encoding_, entry.native_pc_offset);
     stack_map.SetRegisterMask(stack_map_encoding_, entry.register_mask);
     if (entry.sp_mask != nullptr) {
       stack_map.SetStackMask(stack_map_encoding_, *entry.sp_mask);
     }

     if (entry.num_dex_registers == 0) {
       // No dex map available.
       stack_map.SetDexRegisterMapOffset(stack_map_encoding_, StackMap::kNoDexRegisterMap);
     } else {
       // Search for an entry with the same dex map.
       if (entry.same_dex_register_map_as_ != kNoSameDexMapFound) {
         // If we have a hit reuse the offset.
         stack_map.SetDexRegisterMapOffset(
             stack_map_encoding_,
             code_info.GetStackMapAt(entry.same_dex_register_map_as_, stack_map_encoding_)
                      .GetDexRegisterMapOffset(stack_map_encoding_));
       } else {
         // New dex registers maps should be added to the stack map.
         MemoryRegion register_region = dex_register_locations_region.Subregion(
             next_dex_register_map_offset,
             ComputeDexRegisterMapSize(entry.num_dex_registers, *entry.live_dex_registers_mask));
         next_dex_register_map_offset += register_region.size();
         DexRegisterMap dex_register_map(register_region);
         stack_map.SetDexRegisterMapOffset(
             stack_map_encoding_, register_region.start() - dex_register_locations_region.start());

         // Set the dex register location.
         FillInDexRegisterMap(dex_register_map,
                              entry.num_dex_registers,
                              *entry.live_dex_registers_mask,
                              entry.dex_register_locations_start_index);
       }
     }

     // Set the inlining info.
     if (entry.inlining_depth != 0) {
       MemoryRegion inline_region = inline_infos_region.Subregion(
           next_inline_info_offset,
           InlineInfo::kFixedSize + entry.inlining_depth * InlineInfo::SingleEntrySize());
       next_inline_info_offset += inline_region.size();
       InlineInfo inline_info(inline_region);

       // Currently relative to the dex register map.
       stack_map.SetInlineDescriptorOffset(
           stack_map_encoding_, inline_region.start() - dex_register_locations_region.start());

       inline_info.SetDepth(entry.inlining_depth);
       for (size_t depth = 0; depth < entry.inlining_depth; ++depth) {
         InlineInfoEntry inline_entry = inline_infos_.Get(depth + entry.inline_infos_start_index);
         inline_info.SetMethodIndexAtDepth(depth, inline_entry.method_index);
         inline_info.SetDexPcAtDepth(depth, inline_entry.dex_pc);
         inline_info.SetInvokeTypeAtDepth(depth, inline_entry.invoke_type);
         if (inline_entry.num_dex_registers == 0) {
           // No dex map available.
           inline_info.SetDexRegisterMapOffsetAtDepth(depth, StackMap::kNoDexRegisterMap);
           DCHECK(inline_entry.live_dex_registers_mask == nullptr);
         } else {
           MemoryRegion register_region = dex_register_locations_region.Subregion(
               next_dex_register_map_offset,
               ComputeDexRegisterMapSize(inline_entry.num_dex_registers,
                                         *inline_entry.live_dex_registers_mask));
           next_dex_register_map_offset += register_region.size();
           DexRegisterMap dex_register_map(register_region);
           inline_info.SetDexRegisterMapOffsetAtDepth(
             depth, register_region.start() - dex_register_locations_region.start());

           FillInDexRegisterMap(dex_register_map,
                                inline_entry.num_dex_registers,
                                *inline_entry.live_dex_registers_mask,
                                inline_entry.dex_register_locations_start_index);
         }
       }
     } else {
       if (inline_info_size_ != 0) {
         stack_map.SetInlineDescriptorOffset(stack_map_encoding_, StackMap::kNoInlineInfo);
       }
     }
   }
 }

 void StackMapStream::FillInDexRegisterMap(DexRegisterMap dex_register_map,
                                           uint32_t num_dex_registers,
                                           const BitVector& live_dex_registers_mask,
                                           uint32_t start_index_in_dex_register_locations) const {
   dex_register_map.SetLiveBitMask(num_dex_registers, live_dex_registers_mask);
   // Set the dex register location mapping data.
   for (size_t dex_register_number = 0, index_in_dex_register_locations = 0;
        dex_register_number < num_dex_registers;
        ++dex_register_number) {
     if (live_dex_registers_mask.IsBitSet(dex_register_number)) {
       size_t location_catalog_entry_index = dex_register_locations_.Get(
           start_index_in_dex_register_locations + index_in_dex_register_locations);
       dex_register_map.SetLocationCatalogEntryIndex(
           index_in_dex_register_locations,
           location_catalog_entry_index,
           num_dex_registers,
           location_catalog_entries_.Size());
       ++index_in_dex_register_locations;
     }
   }
 }

 size_t StackMapStream::FindEntryWithTheSameDexMap() {
   size_t current_entry_index = stack_maps_.Size();
   auto entries_it = dex_map_hash_to_stack_map_indices_.find(current_entry_.dex_register_map_hash);
   if (entries_it == dex_map_hash_to_stack_map_indices_.end()) {
     // We don't have a perfect hash functions so we need a list to collect all stack maps
     // which might have the same dex register map.
     GrowableArray<uint32_t> stack_map_indices(allocator_, 1);
     stack_map_indices.Add(current_entry_index);
     dex_map_hash_to_stack_map_indices_.Put(current_entry_.dex_register_map_hash, stack_map_indices);
     return kNoSameDexMapFound;
   }

   // We might have collisions, so we need to check whether or not we really have a match.
   for (size_t i = 0; i < entries_it->second.Size(); i++) {
     size_t test_entry_index = entries_it->second.Get(i);
     if (HaveTheSameDexMaps(stack_maps_.Get(test_entry_index), current_entry_)) {
       return test_entry_index;
     }
   }
   entries_it->second.Add(current_entry_index);
   return kNoSameDexMapFound;
 }

 bool StackMapStream::HaveTheSameDexMaps(const StackMapEntry& a, const StackMapEntry& b) const {
   if (a.live_dex_registers_mask == nullptr && b.live_dex_registers_mask == nullptr) {
     return true;
   }
   if (a.live_dex_registers_mask == nullptr || b.live_dex_registers_mask == nullptr) {
     return false;
   }
   if (a.num_dex_registers != b.num_dex_registers) {
     return false;
   }

   int index_in_dex_register_locations = 0;
   for (uint32_t i = 0; i < a.num_dex_registers; i++) {
     if (a.live_dex_registers_mask->IsBitSet(i) != b.live_dex_registers_mask->IsBitSet(i)) {
       return false;
     }
     if (a.live_dex_registers_mask->IsBitSet(i)) {
       size_t a_loc = dex_register_locations_.Get(
           a.dex_register_locations_start_index + index_in_dex_register_locations);
       size_t b_loc = dex_register_locations_.Get(
           b.dex_register_locations_start_index + index_in_dex_register_locations);
       if (a_loc != b_loc) {
         return false;
       }
       ++index_in_dex_register_locations;
     }
   }
   return true;
 }

 }  // namespace art
	/*
	* Copyright (C) 2015 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.
	*/
	#include "stack_map_stream.h"

	namespace art {

	void StackMapStream::BeginStackMapEntry(uint32_t dex_pc,
	uint32_t native_pc_offset,
	uint32_t register_mask,
	BitVector* sp_mask,
	uint32_t num_dex_registers,
	uint8_t inlining_depth) {
	DCHECK_EQ(0u, current_entry_.dex_pc) << "EndStackMapEntry not called after BeginStackMapEntry";
	current_entry_.dex_pc = dex_pc;
	current_entry_.native_pc_offset = native_pc_offset;
	current_entry_.register_mask = register_mask;
	current_entry_.sp_mask = sp_mask;
	current_entry_.num_dex_registers = num_dex_registers;
	current_entry_.inlining_depth = inlining_depth;
	current_entry_.dex_register_locations_start_index = dex_register_locations_.Size();
	current_entry_.inline_infos_start_index = inline_infos_.Size();
	current_entry_.dex_register_map_hash = 0;
	current_entry_.same_dex_register_map_as_ = kNoSameDexMapFound;
	if (num_dex_registers != 0) {
	current_entry_.live_dex_registers_mask =
	new (allocator_) ArenaBitVector(allocator_, num_dex_registers, true);
	} else {
	current_entry_.live_dex_registers_mask = nullptr;
	}

	if (sp_mask != nullptr) {
	stack_mask_max_ = std::max(stack_mask_max_, sp_mask->GetHighestBitSet());
	}
	if (inlining_depth > 0) {
	number_of_stack_maps_with_inline_info_++;
	}

	dex_pc_max_ = std::max(dex_pc_max_, dex_pc);
	register_mask_max_ = std::max(register_mask_max_, register_mask);
	current_dex_register_ = 0;
	}

	void StackMapStream::EndStackMapEntry() {
	current_entry_.same_dex_register_map_as_ = FindEntryWithTheSameDexMap();
	stack_maps_.Add(current_entry_);
	current_entry_ = StackMapEntry();
	}

	void StackMapStream::AddDexRegisterEntry(DexRegisterLocation::Kind kind, int32_t value) {
	if (kind != DexRegisterLocation::Kind::kNone) {
	// Ensure we only use non-compressed location kind at this stage.
	DCHECK(DexRegisterLocation::IsShortLocationKind(kind))
	<< DexRegisterLocation::PrettyDescriptor(kind);
	DexRegisterLocation location(kind, value);

	// Look for Dex register `location` in the location catalog (using the
	// companion hash map of locations to indices). Use its index if it
	// is already in the location catalog. If not, insert it (in the
	// location catalog and the hash map) and use the newly created index.
	auto it = location_catalog_entries_indices_.Find(location);
	if (it != location_catalog_entries_indices_.end()) {
	// Retrieve the index from the hash map.
	dex_register_locations_.Add(it->second);
	} else {
	// Create a new entry in the location catalog and the hash map.
	size_t index = location_catalog_entries_.Size();
	location_catalog_entries_.Add(location);
	dex_register_locations_.Add(index);
	location_catalog_entries_indices_.Insert(std::make_pair(location, index));
	}

	if (in_inline_frame_) {
	// TODO: Support sharing DexRegisterMap across InlineInfo.
	DCHECK_LT(current_dex_register_, current_inline_info_.num_dex_registers);
	current_inline_info_.live_dex_registers_mask->SetBit(current_dex_register_);
	} else {
	DCHECK_LT(current_dex_register_, current_entry_.num_dex_registers);
	current_entry_.live_dex_registers_mask->SetBit(current_dex_register_);
	current_entry_.dex_register_map_hash += (1 <<
	(current_dex_register_ % (sizeof(current_entry_.dex_register_map_hash) * kBitsPerByte)));
	current_entry_.dex_register_map_hash += static_cast<uint32_t>(value);
	current_entry_.dex_register_map_hash += static_cast<uint32_t>(kind);
	}
	}
	current_dex_register_++;
	}

	void StackMapStream::BeginInlineInfoEntry(uint32_t method_index,
	uint32_t dex_pc,
	InvokeType invoke_type,
	uint32_t num_dex_registers) {
	DCHECK(!in_inline_frame_);
	in_inline_frame_ = true;
	current_inline_info_.method_index = method_index;
	current_inline_info_.dex_pc = dex_pc;
	current_inline_info_.invoke_type = invoke_type;
	current_inline_info_.num_dex_registers = num_dex_registers;
	current_inline_info_.dex_register_locations_start_index = dex_register_locations_.Size();
	if (num_dex_registers != 0) {
	current_inline_info_.live_dex_registers_mask =
	new (allocator_) ArenaBitVector(allocator_, num_dex_registers, true);
	} else {
	current_inline_info_.live_dex_registers_mask = nullptr;
	}
	current_dex_register_ = 0;
	}

	void StackMapStream::EndInlineInfoEntry() {
	DCHECK(in_inline_frame_);
	DCHECK_EQ(current_dex_register_, current_inline_info_.num_dex_registers)
	<< "Inline information contains less registers than expected";
	in_inline_frame_ = false;
	inline_infos_.Add(current_inline_info_);
	current_inline_info_ = InlineInfoEntry();
	}

	uint32_t StackMapStream::ComputeMaxNativePcOffset() const {
	uint32_t max_native_pc_offset = 0u;
	for (size_t i = 0, size = stack_maps_.Size(); i != size; ++i) {
	max_native_pc_offset = std::max(max_native_pc_offset, stack_maps_.Get(i).native_pc_offset);
	}
	return max_native_pc_offset;
	}

	size_t StackMapStream::PrepareForFillIn() {
	int stack_mask_number_of_bits = stack_mask_max_ + 1; // Need room for max element too.
	stack_mask_size_ = RoundUp(stack_mask_number_of_bits, kBitsPerByte) / kBitsPerByte;
	inline_info_size_ = ComputeInlineInfoSize();
	dex_register_maps_size_ = ComputeDexRegisterMapsSize();
	uint32_t max_native_pc_offset = ComputeMaxNativePcOffset();
	stack_map_encoding_ = StackMapEncoding::CreateFromSizes(stack_mask_size_,
	inline_info_size_,
	dex_register_maps_size_,
	dex_pc_max_,
	max_native_pc_offset,
	register_mask_max_);
	stack_maps_size_ = stack_maps_.Size() * stack_map_encoding_.ComputeStackMapSize();
	dex_register_location_catalog_size_ = ComputeDexRegisterLocationCatalogSize();

	// Note: use RoundUp to word-size here if you want CodeInfo objects to be word aligned.
	needed_size_ = CodeInfo::kFixedSize
	+ stack_maps_size_
	+ dex_register_location_catalog_size_
	+ dex_register_maps_size_
	+ inline_info_size_;

	stack_maps_start_ = CodeInfo::kFixedSize;
	// TODO: Move the catalog at the end. It is currently too expensive at runtime
	// to compute its size (note that we do not encode that size in the CodeInfo).
	dex_register_location_catalog_start_ = stack_maps_start_ + stack_maps_size_;
	dex_register_maps_start_ =
	dex_register_location_catalog_start_ + dex_register_location_catalog_size_;
	inline_infos_start_ = dex_register_maps_start_ + dex_register_maps_size_;

	return needed_size_;
	}

	size_t StackMapStream::ComputeDexRegisterLocationCatalogSize() const {
	size_t size = DexRegisterLocationCatalog::kFixedSize;
	for (size_t location_catalog_entry_index = 0;
	location_catalog_entry_index < location_catalog_entries_.Size();
	++location_catalog_entry_index) {
	DexRegisterLocation dex_register_location =
	location_catalog_entries_.Get(location_catalog_entry_index);
	size += DexRegisterLocationCatalog::EntrySize(dex_register_location);
	}
	return size;
	}

	size_t StackMapStream::ComputeDexRegisterMapSize(uint32_t num_dex_registers,
	const BitVector& live_dex_registers_mask) const {
	// Size of the map in bytes.
	size_t size = DexRegisterMap::kFixedSize;
	// Add the live bit mask for the Dex register liveness.
	size += DexRegisterMap::GetLiveBitMaskSize(num_dex_registers);
	// Compute the size of the set of live Dex register entries.
	size_t number_of_live_dex_registers = 0;
	for (size_t dex_register_number = 0;
	dex_register_number < num_dex_registers;
	++dex_register_number) {
	if (live_dex_registers_mask.IsBitSet(dex_register_number)) {
	++number_of_live_dex_registers;
	}
	}
	size_t map_entries_size_in_bits =
	DexRegisterMap::SingleEntrySizeInBits(location_catalog_entries_.Size())
	* number_of_live_dex_registers;
	size_t map_entries_size_in_bytes =
	RoundUp(map_entries_size_in_bits, kBitsPerByte) / kBitsPerByte;
	size += map_entries_size_in_bytes;
	return size;
	}

	size_t StackMapStream::ComputeDexRegisterMapsSize() const {
	size_t size = 0;
	size_t inline_info_index = 0;
	for (size_t i = 0; i < stack_maps_.Size(); ++i) {
	StackMapEntry entry = stack_maps_.Get(i);
	if (entry.same_dex_register_map_as_ == kNoSameDexMapFound) {
	size += ComputeDexRegisterMapSize(entry.num_dex_registers, *entry.live_dex_registers_mask);
	} else {
	// Entries with the same dex map will have the same offset.
	}
	for (size_t j = 0; j < entry.inlining_depth; ++j) {
	InlineInfoEntry inline_entry = inline_infos_.Get(inline_info_index++);
	size += ComputeDexRegisterMapSize(inline_entry.num_dex_registers,
	*inline_entry.live_dex_registers_mask);
	}
	}
	return size;
	}

	size_t StackMapStream::ComputeInlineInfoSize() const {
	return inline_infos_.Size() * InlineInfo::SingleEntrySize()
	// For encoding the depth.
	+ (number_of_stack_maps_with_inline_info_ * InlineInfo::kFixedSize);
	}

	void StackMapStream::FillIn(MemoryRegion region) {
	DCHECK_EQ(0u, current_entry_.dex_pc) << "EndStackMapEntry not called after BeginStackMapEntry";
	DCHECK_NE(0u, needed_size_) << "PrepareForFillIn not called before FillIn";

	CodeInfo code_info(region);
	DCHECK_EQ(region.size(), needed_size_);
	code_info.SetOverallSize(region.size());

	MemoryRegion dex_register_locations_region = region.Subregion(
	dex_register_maps_start_, dex_register_maps_size_);

	MemoryRegion inline_infos_region = region.Subregion(
	inline_infos_start_, inline_info_size_);

	code_info.SetEncoding(stack_map_encoding_);
	code_info.SetNumberOfStackMaps(stack_maps_.Size());
	DCHECK_EQ(code_info.GetStackMapsSize(code_info.ExtractEncoding()), stack_maps_size_);

	// Set the Dex register location catalog.
	code_info.SetNumberOfLocationCatalogEntries(location_catalog_entries_.Size());
	MemoryRegion dex_register_location_catalog_region = region.Subregion(
	dex_register_location_catalog_start_, dex_register_location_catalog_size_);
	DexRegisterLocationCatalog dex_register_location_catalog(dex_register_location_catalog_region);
	// Offset in `dex_register_location_catalog` where to store the next
	// register location.
	size_t location_catalog_offset = DexRegisterLocationCatalog::kFixedSize;
	for (size_t i = 0, e = location_catalog_entries_.Size(); i < e; ++i) {
	DexRegisterLocation dex_register_location = location_catalog_entries_.Get(i);
	dex_register_location_catalog.SetRegisterInfo(location_catalog_offset, dex_register_location);
	location_catalog_offset += DexRegisterLocationCatalog::EntrySize(dex_register_location);
	}
	// Ensure we reached the end of the Dex registers location_catalog.
	DCHECK_EQ(location_catalog_offset, dex_register_location_catalog_region.size());

	uintptr_t next_dex_register_map_offset = 0;
	uintptr_t next_inline_info_offset = 0;
	for (size_t i = 0, e = stack_maps_.Size(); i < e; ++i) {
	StackMap stack_map = code_info.GetStackMapAt(i, stack_map_encoding_);
	StackMapEntry entry = stack_maps_.Get(i);

	stack_map.SetDexPc(stack_map_encoding_, entry.dex_pc);
	stack_map.SetNativePcOffset(stack_map_encoding_, entry.native_pc_offset);
	stack_map.SetRegisterMask(stack_map_encoding_, entry.register_mask);
	if (entry.sp_mask != nullptr) {
	stack_map.SetStackMask(stack_map_encoding_, *entry.sp_mask);
	}

	if (entry.num_dex_registers == 0) {
	// No dex map available.
	stack_map.SetDexRegisterMapOffset(stack_map_encoding_, StackMap::kNoDexRegisterMap);
	} else {
	// Search for an entry with the same dex map.
	if (entry.same_dex_register_map_as_ != kNoSameDexMapFound) {
	// If we have a hit reuse the offset.
	stack_map.SetDexRegisterMapOffset(
	stack_map_encoding_,
	code_info.GetStackMapAt(entry.same_dex_register_map_as_, stack_map_encoding_)
	.GetDexRegisterMapOffset(stack_map_encoding_));
	} else {
	// New dex registers maps should be added to the stack map.
	MemoryRegion register_region = dex_register_locations_region.Subregion(
	next_dex_register_map_offset,
	ComputeDexRegisterMapSize(entry.num_dex_registers, *entry.live_dex_registers_mask));
	next_dex_register_map_offset += register_region.size();
	DexRegisterMap dex_register_map(register_region);
	stack_map.SetDexRegisterMapOffset(
	stack_map_encoding_, register_region.start() - dex_register_locations_region.start());

	// Set the dex register location.
	FillInDexRegisterMap(dex_register_map,
	entry.num_dex_registers,
	*entry.live_dex_registers_mask,
	entry.dex_register_locations_start_index);
	}
	}

	// Set the inlining info.
	if (entry.inlining_depth != 0) {
	MemoryRegion inline_region = inline_infos_region.Subregion(
	next_inline_info_offset,
	InlineInfo::kFixedSize + entry.inlining_depth * InlineInfo::SingleEntrySize());
	next_inline_info_offset += inline_region.size();
	InlineInfo inline_info(inline_region);

	// Currently relative to the dex register map.
	stack_map.SetInlineDescriptorOffset(
	stack_map_encoding_, inline_region.start() - dex_register_locations_region.start());

	inline_info.SetDepth(entry.inlining_depth);
	for (size_t depth = 0; depth < entry.inlining_depth; ++depth) {
	InlineInfoEntry inline_entry = inline_infos_.Get(depth + entry.inline_infos_start_index);
	inline_info.SetMethodIndexAtDepth(depth, inline_entry.method_index);
	inline_info.SetDexPcAtDepth(depth, inline_entry.dex_pc);
	inline_info.SetInvokeTypeAtDepth(depth, inline_entry.invoke_type);
	if (inline_entry.num_dex_registers == 0) {
	// No dex map available.
	inline_info.SetDexRegisterMapOffsetAtDepth(depth, StackMap::kNoDexRegisterMap);
	DCHECK(inline_entry.live_dex_registers_mask == nullptr);
	} else {
	MemoryRegion register_region = dex_register_locations_region.Subregion(
	next_dex_register_map_offset,
	ComputeDexRegisterMapSize(inline_entry.num_dex_registers,
	*inline_entry.live_dex_registers_mask));
	next_dex_register_map_offset += register_region.size();
	DexRegisterMap dex_register_map(register_region);
	inline_info.SetDexRegisterMapOffsetAtDepth(
	depth, register_region.start() - dex_register_locations_region.start());

	FillInDexRegisterMap(dex_register_map,
	inline_entry.num_dex_registers,
	*inline_entry.live_dex_registers_mask,
	inline_entry.dex_register_locations_start_index);
	}
	}
	} else {
	if (inline_info_size_ != 0) {
	stack_map.SetInlineDescriptorOffset(stack_map_encoding_, StackMap::kNoInlineInfo);
	}
	}
	}
	}

	void StackMapStream::FillInDexRegisterMap(DexRegisterMap dex_register_map,
	uint32_t num_dex_registers,
	const BitVector& live_dex_registers_mask,
	uint32_t start_index_in_dex_register_locations) const {
	dex_register_map.SetLiveBitMask(num_dex_registers, live_dex_registers_mask);
	// Set the dex register location mapping data.
	for (size_t dex_register_number = 0, index_in_dex_register_locations = 0;
	dex_register_number < num_dex_registers;
	++dex_register_number) {
	if (live_dex_registers_mask.IsBitSet(dex_register_number)) {
	size_t location_catalog_entry_index = dex_register_locations_.Get(
	start_index_in_dex_register_locations + index_in_dex_register_locations);
	dex_register_map.SetLocationCatalogEntryIndex(
	index_in_dex_register_locations,
	location_catalog_entry_index,
	num_dex_registers,
	location_catalog_entries_.Size());
	++index_in_dex_register_locations;
	}
	}
	}

	size_t StackMapStream::FindEntryWithTheSameDexMap() {
	size_t current_entry_index = stack_maps_.Size();
	auto entries_it = dex_map_hash_to_stack_map_indices_.find(current_entry_.dex_register_map_hash);
	if (entries_it == dex_map_hash_to_stack_map_indices_.end()) {
	// We don't have a perfect hash functions so we need a list to collect all stack maps
	// which might have the same dex register map.
	GrowableArray<uint32_t> stack_map_indices(allocator_, 1);
	stack_map_indices.Add(current_entry_index);
	dex_map_hash_to_stack_map_indices_.Put(current_entry_.dex_register_map_hash, stack_map_indices);
	return kNoSameDexMapFound;
	}

	// We might have collisions, so we need to check whether or not we really have a match.
	for (size_t i = 0; i < entries_it->second.Size(); i++) {
	size_t test_entry_index = entries_it->second.Get(i);
	if (HaveTheSameDexMaps(stack_maps_.Get(test_entry_index), current_entry_)) {
	return test_entry_index;
	}
	}
	entries_it->second.Add(current_entry_index);
	return kNoSameDexMapFound;
	}

	bool StackMapStream::HaveTheSameDexMaps(const StackMapEntry& a, const StackMapEntry& b) const {
	if (a.live_dex_registers_mask == nullptr && b.live_dex_registers_mask == nullptr) {
	return true;
	}
	if (a.live_dex_registers_mask == nullptr \|\| b.live_dex_registers_mask == nullptr) {
	return false;
	}
	if (a.num_dex_registers != b.num_dex_registers) {
	return false;
	}

	int index_in_dex_register_locations = 0;
	for (uint32_t i = 0; i < a.num_dex_registers; i++) {
	if (a.live_dex_registers_mask->IsBitSet(i) != b.live_dex_registers_mask->IsBitSet(i)) {
	return false;
	}
	if (a.live_dex_registers_mask->IsBitSet(i)) {
	size_t a_loc = dex_register_locations_.Get(
	a.dex_register_locations_start_index + index_in_dex_register_locations);
	size_t b_loc = dex_register_locations_.Get(
	b.dex_register_locations_start_index + index_in_dex_register_locations);
	if (a_loc != b_loc) {
	return false;
	}
	++index_in_dex_register_locations;
	}
	}
	return true;
	}

	} // namespace art