compiler/optimizing/stack_map_stream.cc - LeafOS-Project/android_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"

 #include <memory>

 #include "art_method-inl.h"
 #include "base/stl_util.h"
 #include "dex/dex_file_types.h"
 #include "optimizing/optimizing_compiler.h"
 #include "runtime.h"
 #include "scoped_thread_state_change-inl.h"
 #include "stack_map.h"

 namespace art {

 constexpr static bool kVerifyStackMaps = kIsDebugBuild;

 uint32_t StackMapStream::GetStackMapNativePcOffset(size_t i) {
   return StackMap::UnpackNativePc(stack_maps_[i][StackMap::kPackedNativePc], instruction_set_);
 }

 void StackMapStream::SetStackMapNativePcOffset(size_t i, uint32_t native_pc_offset) {
   stack_maps_[i][StackMap::kPackedNativePc] =
       StackMap::PackNativePc(native_pc_offset, instruction_set_);
 }

 void StackMapStream::BeginMethod(size_t frame_size_in_bytes,
                                  size_t core_spill_mask,
                                  size_t fp_spill_mask,
                                  uint32_t num_dex_registers) {
   DCHECK(!in_method_) << "Mismatched Begin/End calls";
   in_method_ = true;
   DCHECK_EQ(packed_frame_size_, 0u) << "BeginMethod was already called";

   DCHECK_ALIGNED(frame_size_in_bytes, kStackAlignment);
   packed_frame_size_ = frame_size_in_bytes / kStackAlignment;
   core_spill_mask_ = core_spill_mask;
   fp_spill_mask_ = fp_spill_mask;
   num_dex_registers_ = num_dex_registers;

   if (kVerifyStackMaps) {
     dchecks_.emplace_back([=](const CodeInfo& code_info) {
       DCHECK_EQ(code_info.packed_frame_size_, frame_size_in_bytes / kStackAlignment);
       DCHECK_EQ(code_info.core_spill_mask_, core_spill_mask);
       DCHECK_EQ(code_info.fp_spill_mask_, fp_spill_mask);
       DCHECK_EQ(code_info.number_of_dex_registers_, num_dex_registers);
     });
   }
 }

 void StackMapStream::EndMethod() {
   DCHECK(in_method_) << "Mismatched Begin/End calls";
   in_method_ = false;

   // Read the stack masks now. The compiler might have updated them.
   for (size_t i = 0; i < lazy_stack_masks_.size(); i++) {
     BitVector* stack_mask = lazy_stack_masks_[i];
     if (stack_mask != nullptr && stack_mask->GetNumberOfBits() != 0) {
       stack_maps_[i][StackMap::kStackMaskIndex] =
           stack_masks_.Dedup(stack_mask->GetRawStorage(), stack_mask->GetNumberOfBits());
     }
   }
 }

 void StackMapStream::BeginStackMapEntry(uint32_t dex_pc,
                                         uint32_t native_pc_offset,
                                         uint32_t register_mask,
                                         BitVector* stack_mask,
                                         StackMap::Kind kind,
                                         bool needs_vreg_info) {
   DCHECK(in_method_) << "Call BeginMethod first";
   DCHECK(!in_stack_map_) << "Mismatched Begin/End calls";
   in_stack_map_ = true;

   current_stack_map_ = BitTableBuilder<StackMap>::Entry();
   current_stack_map_[StackMap::kKind] = static_cast<uint32_t>(kind);
   current_stack_map_[StackMap::kPackedNativePc] =
       StackMap::PackNativePc(native_pc_offset, instruction_set_);
   current_stack_map_[StackMap::kDexPc] = dex_pc;
   if (stack_maps_.size() > 0) {
     // Check that non-catch stack maps are sorted by pc.
     // Catch stack maps are at the end and may be unordered.
     if (stack_maps_.back()[StackMap::kKind] == StackMap::Kind::Catch) {
       DCHECK(current_stack_map_[StackMap::kKind] == StackMap::Kind::Catch);
     } else if (current_stack_map_[StackMap::kKind] != StackMap::Kind::Catch) {
       DCHECK_LE(stack_maps_.back()[StackMap::kPackedNativePc],
                 current_stack_map_[StackMap::kPackedNativePc]);
     }
   }
   if (register_mask != 0) {
     uint32_t shift = LeastSignificantBit(register_mask);
     BitTableBuilder<RegisterMask>::Entry entry;
     entry[RegisterMask::kValue] = register_mask >> shift;
     entry[RegisterMask::kShift] = shift;
     current_stack_map_[StackMap::kRegisterMaskIndex] = register_masks_.Dedup(&entry);
   }
   // The compiler assumes the bit vector will be read during PrepareForFillIn(),
   // and it might modify the data before that. Therefore, just store the pointer.
   // See ClearSpillSlotsFromLoopPhisInStackMap in code_generator.h.
   lazy_stack_masks_.push_back(stack_mask);
   current_inline_infos_.clear();
   current_dex_registers_.clear();
   expected_num_dex_registers_ = needs_vreg_info  ? num_dex_registers_ : 0u;

   if (kVerifyStackMaps) {
     size_t stack_map_index = stack_maps_.size();
     // Create lambda method, which will be executed at the very end to verify data.
     // Parameters and local variables will be captured(stored) by the lambda "[=]".
     dchecks_.emplace_back([=](const CodeInfo& code_info) {
       if (kind == StackMap::Kind::Default || kind == StackMap::Kind::OSR) {
         StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset,
                                                                     instruction_set_);
         CHECK_EQ(stack_map.Row(), stack_map_index);
       } else if (kind == StackMap::Kind::Catch) {
         StackMap stack_map = code_info.GetCatchStackMapForDexPc(dex_pc);
         CHECK_EQ(stack_map.Row(), stack_map_index);
       }
       StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
       CHECK_EQ(stack_map.GetNativePcOffset(instruction_set_), native_pc_offset);
       CHECK_EQ(stack_map.GetKind(), static_cast<uint32_t>(kind));
       CHECK_EQ(stack_map.GetDexPc(), dex_pc);
       CHECK_EQ(code_info.GetRegisterMaskOf(stack_map), register_mask);
       BitMemoryRegion seen_stack_mask = code_info.GetStackMaskOf(stack_map);
       CHECK_GE(seen_stack_mask.size_in_bits(), stack_mask ? stack_mask->GetNumberOfBits() : 0);
       for (size_t b = 0; b < seen_stack_mask.size_in_bits(); b++) {
         CHECK_EQ(seen_stack_mask.LoadBit(b), stack_mask != nullptr && stack_mask->IsBitSet(b));
       }
     });
   }
 }

 void StackMapStream::EndStackMapEntry() {
   DCHECK(in_stack_map_) << "Mismatched Begin/End calls";
   in_stack_map_ = false;

   // Generate index into the InlineInfo table.
   size_t inlining_depth = current_inline_infos_.size();
   if (!current_inline_infos_.empty()) {
     current_inline_infos_.back()[InlineInfo::kIsLast] = InlineInfo::kLast;
     current_stack_map_[StackMap::kInlineInfoIndex] =
         inline_infos_.Dedup(current_inline_infos_.data(), current_inline_infos_.size());
   }

   // Generate delta-compressed dex register map.
   size_t num_dex_registers = current_dex_registers_.size();
   if (!current_dex_registers_.empty()) {
     DCHECK_EQ(expected_num_dex_registers_, current_dex_registers_.size());
     CreateDexRegisterMap();
   }

   stack_maps_.Add(current_stack_map_);

   if (kVerifyStackMaps) {
     size_t stack_map_index = stack_maps_.size() - 1;
     dchecks_.emplace_back([=](const CodeInfo& code_info) {
       StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
       CHECK_EQ(stack_map.HasDexRegisterMap(), (num_dex_registers != 0));
       CHECK_EQ(stack_map.HasInlineInfo(), (inlining_depth != 0));
       CHECK_EQ(code_info.GetInlineInfosOf(stack_map).size(), inlining_depth);
     });
   }
 }

 void StackMapStream::BeginInlineInfoEntry(ArtMethod* method,
                                           uint32_t dex_pc,
                                           uint32_t num_dex_registers,
                                           const DexFile* outer_dex_file) {
   DCHECK(in_stack_map_) << "Call BeginStackMapEntry first";
   DCHECK(!in_inline_info_) << "Mismatched Begin/End calls";
   in_inline_info_ = true;
   DCHECK_EQ(expected_num_dex_registers_, current_dex_registers_.size());

   expected_num_dex_registers_ += num_dex_registers;

   BitTableBuilder<InlineInfo>::Entry entry;
   entry[InlineInfo::kIsLast] = InlineInfo::kMore;
   entry[InlineInfo::kDexPc] = dex_pc;
   entry[InlineInfo::kNumberOfDexRegisters] = static_cast<uint32_t>(expected_num_dex_registers_);
   if (EncodeArtMethodInInlineInfo(method)) {
     entry[InlineInfo::kArtMethodHi] = High32Bits(reinterpret_cast<uintptr_t>(method));
     entry[InlineInfo::kArtMethodLo] = Low32Bits(reinterpret_cast<uintptr_t>(method));
   } else {
     if (dex_pc != static_cast<uint32_t>(-1) && kIsDebugBuild) {
       ScopedObjectAccess soa(Thread::Current());
       DCHECK(IsSameDexFile(*outer_dex_file, *method->GetDexFile()));
     }
     uint32_t dex_method_index = method->GetDexMethodIndex();
     entry[InlineInfo::kMethodInfoIndex] = method_infos_.Dedup({dex_method_index});
   }
   current_inline_infos_.push_back(entry);

   if (kVerifyStackMaps) {
     size_t stack_map_index = stack_maps_.size();
     size_t depth = current_inline_infos_.size() - 1;
     dchecks_.emplace_back([=](const CodeInfo& code_info) {
       StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
       InlineInfo inline_info = code_info.GetInlineInfosOf(stack_map)[depth];
       CHECK_EQ(inline_info.GetDexPc(), dex_pc);
       bool encode_art_method = EncodeArtMethodInInlineInfo(method);
       CHECK_EQ(inline_info.EncodesArtMethod(), encode_art_method);
       if (encode_art_method) {
         CHECK_EQ(inline_info.GetArtMethod(), method);
       } else {
         CHECK_EQ(code_info.GetMethodIndexOf(inline_info), method->GetDexMethodIndex());
       }
     });
   }
 }

 void StackMapStream::EndInlineInfoEntry() {
   DCHECK(in_inline_info_) << "Mismatched Begin/End calls";
   in_inline_info_ = false;
   DCHECK_EQ(expected_num_dex_registers_, current_dex_registers_.size());
 }

 // Create delta-compressed dex register map based on the current list of DexRegisterLocations.
 // All dex registers for a stack map are concatenated - inlined registers are just appended.
 void StackMapStream::CreateDexRegisterMap() {
   // These are fields rather than local variables so that we can reuse the reserved memory.
   temp_dex_register_mask_.ClearAllBits();
   temp_dex_register_map_.clear();

   // Ensure that the arrays that hold previous state are big enough to be safely indexed below.
   if (previous_dex_registers_.size() < current_dex_registers_.size()) {
     previous_dex_registers_.resize(current_dex_registers_.size(), DexRegisterLocation::None());
     dex_register_timestamp_.resize(current_dex_registers_.size(), 0u);
   }

   // Set bit in the mask for each register that has been changed since the previous stack map.
   // Modified registers are stored in the catalogue and the catalogue index added to the list.
   for (size_t i = 0; i < current_dex_registers_.size(); i++) {
     DexRegisterLocation reg = current_dex_registers_[i];
     // Distance is difference between this index and the index of last modification.
     uint32_t distance = stack_maps_.size() - dex_register_timestamp_[i];
     if (previous_dex_registers_[i] != reg || distance > kMaxDexRegisterMapSearchDistance) {
       BitTableBuilder<DexRegisterInfo>::Entry entry;
       entry[DexRegisterInfo::kKind] = static_cast<uint32_t>(reg.GetKind());
       entry[DexRegisterInfo::kPackedValue] =
           DexRegisterInfo::PackValue(reg.GetKind(), reg.GetValue());
       uint32_t index = reg.IsLive() ? dex_register_catalog_.Dedup(&entry) : kNoValue;
       temp_dex_register_mask_.SetBit(i);
       temp_dex_register_map_.push_back({index});
       previous_dex_registers_[i] = reg;
       dex_register_timestamp_[i] = stack_maps_.size();
     }
   }

   // Set the mask and map for the current StackMap (which includes inlined registers).
   if (temp_dex_register_mask_.GetNumberOfBits() != 0) {
     current_stack_map_[StackMap::kDexRegisterMaskIndex] =
         dex_register_masks_.Dedup(temp_dex_register_mask_.GetRawStorage(),
                                   temp_dex_register_mask_.GetNumberOfBits());
   }
   if (!current_dex_registers_.empty()) {
     current_stack_map_[StackMap::kDexRegisterMapIndex] =
         dex_register_maps_.Dedup(temp_dex_register_map_.data(),
                                  temp_dex_register_map_.size());
   }

   if (kVerifyStackMaps) {
     size_t stack_map_index = stack_maps_.size();
     // We need to make copy of the current registers for later (when the check is run).
     auto expected_dex_registers = std::make_shared<dchecked_vector<DexRegisterLocation>>(
         current_dex_registers_.begin(), current_dex_registers_.end());
     dchecks_.emplace_back([=](const CodeInfo& code_info) {
       StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
       uint32_t expected_reg = 0;
       for (DexRegisterLocation reg : code_info.GetDexRegisterMapOf(stack_map)) {
         CHECK_EQ((*expected_dex_registers)[expected_reg++], reg);
       }
       for (InlineInfo inline_info : code_info.GetInlineInfosOf(stack_map)) {
         DexRegisterMap map = code_info.GetInlineDexRegisterMapOf(stack_map, inline_info);
         for (DexRegisterLocation reg : map) {
           CHECK_EQ((*expected_dex_registers)[expected_reg++], reg);
         }
       }
       CHECK_EQ(expected_reg, expected_dex_registers->size());
     });
   }
 }

 ScopedArenaVector<uint8_t> StackMapStream::Encode() {
   DCHECK(in_stack_map_ == false) << "Mismatched Begin/End calls";
   DCHECK(in_inline_info_ == false) << "Mismatched Begin/End calls";

   uint32_t flags = (inline_infos_.size() > 0) ? CodeInfo::kHasInlineInfo : 0;
   uint32_t bit_table_flags = 0;
   ForEachBitTable([&bit_table_flags](size_t i, auto bit_table) {
     if (bit_table->size() != 0) {  // Record which bit-tables are stored.
       bit_table_flags |= 1 << i;
     }
   });

   ScopedArenaVector<uint8_t> buffer(allocator_->Adapter(kArenaAllocStackMapStream));
   BitMemoryWriter<ScopedArenaVector<uint8_t>> out(&buffer);
   out.WriteInterleavedVarints(std::array<uint32_t, CodeInfo::kNumHeaders>{
     flags,
     packed_frame_size_,
     core_spill_mask_,
     fp_spill_mask_,
     num_dex_registers_,
     bit_table_flags,
   });
   ForEachBitTable([&out](size_t, auto bit_table) {
     if (bit_table->size() != 0) {  // Skip empty bit-tables.
       bit_table->Encode(out);
     }
   });

   // Verify that we can load the CodeInfo and check some essentials.
   size_t number_of_read_bits;
   CodeInfo code_info(buffer.data(), &number_of_read_bits);
   CHECK_EQ(number_of_read_bits, out.NumberOfWrittenBits());
   CHECK_EQ(code_info.GetNumberOfStackMaps(), stack_maps_.size());

   // Verify all written data (usually only in debug builds).
   if (kVerifyStackMaps) {
     for (const auto& dcheck : dchecks_) {
       dcheck(code_info);
     }
   }

   return buffer;
 }

 }  // 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"

	#include <memory>

	#include "art_method-inl.h"
	#include "base/stl_util.h"
	#include "dex/dex_file_types.h"
	#include "optimizing/optimizing_compiler.h"
	#include "runtime.h"
	#include "scoped_thread_state_change-inl.h"
	#include "stack_map.h"

	namespace art {

	constexpr static bool kVerifyStackMaps = kIsDebugBuild;

	uint32_t StackMapStream::GetStackMapNativePcOffset(size_t i) {
	return StackMap::UnpackNativePc(stack_maps_[i][StackMap::kPackedNativePc], instruction_set_);
	}

	void StackMapStream::SetStackMapNativePcOffset(size_t i, uint32_t native_pc_offset) {
	stack_maps_[i][StackMap::kPackedNativePc] =
	StackMap::PackNativePc(native_pc_offset, instruction_set_);
	}

	void StackMapStream::BeginMethod(size_t frame_size_in_bytes,
	size_t core_spill_mask,
	size_t fp_spill_mask,
	uint32_t num_dex_registers) {
	DCHECK(!in_method_) << "Mismatched Begin/End calls";
	in_method_ = true;
	DCHECK_EQ(packed_frame_size_, 0u) << "BeginMethod was already called";

	DCHECK_ALIGNED(frame_size_in_bytes, kStackAlignment);
	packed_frame_size_ = frame_size_in_bytes / kStackAlignment;
	core_spill_mask_ = core_spill_mask;
	fp_spill_mask_ = fp_spill_mask;
	num_dex_registers_ = num_dex_registers;

	if (kVerifyStackMaps) {
	dchecks_.emplace_back([=](const CodeInfo& code_info) {
	DCHECK_EQ(code_info.packed_frame_size_, frame_size_in_bytes / kStackAlignment);
	DCHECK_EQ(code_info.core_spill_mask_, core_spill_mask);
	DCHECK_EQ(code_info.fp_spill_mask_, fp_spill_mask);
	DCHECK_EQ(code_info.number_of_dex_registers_, num_dex_registers);
	});
	}
	}

	void StackMapStream::EndMethod() {
	DCHECK(in_method_) << "Mismatched Begin/End calls";
	in_method_ = false;

	// Read the stack masks now. The compiler might have updated them.
	for (size_t i = 0; i < lazy_stack_masks_.size(); i++) {
	BitVector* stack_mask = lazy_stack_masks_[i];
	if (stack_mask != nullptr && stack_mask->GetNumberOfBits() != 0) {
	stack_maps_[i][StackMap::kStackMaskIndex] =
	stack_masks_.Dedup(stack_mask->GetRawStorage(), stack_mask->GetNumberOfBits());
	}
	}
	}

	void StackMapStream::BeginStackMapEntry(uint32_t dex_pc,
	uint32_t native_pc_offset,
	uint32_t register_mask,
	BitVector* stack_mask,
	StackMap::Kind kind,
	bool needs_vreg_info) {
	DCHECK(in_method_) << "Call BeginMethod first";
	DCHECK(!in_stack_map_) << "Mismatched Begin/End calls";
	in_stack_map_ = true;

	current_stack_map_ = BitTableBuilder<StackMap>::Entry();
	current_stack_map_[StackMap::kKind] = static_cast<uint32_t>(kind);
	current_stack_map_[StackMap::kPackedNativePc] =
	StackMap::PackNativePc(native_pc_offset, instruction_set_);
	current_stack_map_[StackMap::kDexPc] = dex_pc;
	if (stack_maps_.size() > 0) {
	// Check that non-catch stack maps are sorted by pc.
	// Catch stack maps are at the end and may be unordered.
	if (stack_maps_.back()[StackMap::kKind] == StackMap::Kind::Catch) {
	DCHECK(current_stack_map_[StackMap::kKind] == StackMap::Kind::Catch);
	} else if (current_stack_map_[StackMap::kKind] != StackMap::Kind::Catch) {
	DCHECK_LE(stack_maps_.back()[StackMap::kPackedNativePc],
	current_stack_map_[StackMap::kPackedNativePc]);
	}
	}
	if (register_mask != 0) {
	uint32_t shift = LeastSignificantBit(register_mask);
	BitTableBuilder<RegisterMask>::Entry entry;
	entry[RegisterMask::kValue] = register_mask >> shift;
	entry[RegisterMask::kShift] = shift;
	current_stack_map_[StackMap::kRegisterMaskIndex] = register_masks_.Dedup(&entry);
	}
	// The compiler assumes the bit vector will be read during PrepareForFillIn(),
	// and it might modify the data before that. Therefore, just store the pointer.
	// See ClearSpillSlotsFromLoopPhisInStackMap in code_generator.h.
	lazy_stack_masks_.push_back(stack_mask);
	current_inline_infos_.clear();
	current_dex_registers_.clear();
	expected_num_dex_registers_ = needs_vreg_info ? num_dex_registers_ : 0u;

	if (kVerifyStackMaps) {
	size_t stack_map_index = stack_maps_.size();
	// Create lambda method, which will be executed at the very end to verify data.
	// Parameters and local variables will be captured(stored) by the lambda "[=]".
	dchecks_.emplace_back([=](const CodeInfo& code_info) {
	if (kind == StackMap::Kind::Default \|\| kind == StackMap::Kind::OSR) {
	StackMap stack_map = code_info.GetStackMapForNativePcOffset(native_pc_offset,
	instruction_set_);
	CHECK_EQ(stack_map.Row(), stack_map_index);
	} else if (kind == StackMap::Kind::Catch) {
	StackMap stack_map = code_info.GetCatchStackMapForDexPc(dex_pc);
	CHECK_EQ(stack_map.Row(), stack_map_index);
	}
	StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
	CHECK_EQ(stack_map.GetNativePcOffset(instruction_set_), native_pc_offset);
	CHECK_EQ(stack_map.GetKind(), static_cast<uint32_t>(kind));
	CHECK_EQ(stack_map.GetDexPc(), dex_pc);
	CHECK_EQ(code_info.GetRegisterMaskOf(stack_map), register_mask);
	BitMemoryRegion seen_stack_mask = code_info.GetStackMaskOf(stack_map);
	CHECK_GE(seen_stack_mask.size_in_bits(), stack_mask ? stack_mask->GetNumberOfBits() : 0);
	for (size_t b = 0; b < seen_stack_mask.size_in_bits(); b++) {
	CHECK_EQ(seen_stack_mask.LoadBit(b), stack_mask != nullptr && stack_mask->IsBitSet(b));
	}
	});
	}
	}

	void StackMapStream::EndStackMapEntry() {
	DCHECK(in_stack_map_) << "Mismatched Begin/End calls";
	in_stack_map_ = false;

	// Generate index into the InlineInfo table.
	size_t inlining_depth = current_inline_infos_.size();
	if (!current_inline_infos_.empty()) {
	current_inline_infos_.back()[InlineInfo::kIsLast] = InlineInfo::kLast;
	current_stack_map_[StackMap::kInlineInfoIndex] =
	inline_infos_.Dedup(current_inline_infos_.data(), current_inline_infos_.size());
	}

	// Generate delta-compressed dex register map.
	size_t num_dex_registers = current_dex_registers_.size();
	if (!current_dex_registers_.empty()) {
	DCHECK_EQ(expected_num_dex_registers_, current_dex_registers_.size());
	CreateDexRegisterMap();
	}

	stack_maps_.Add(current_stack_map_);

	if (kVerifyStackMaps) {
	size_t stack_map_index = stack_maps_.size() - 1;
	dchecks_.emplace_back([=](const CodeInfo& code_info) {
	StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
	CHECK_EQ(stack_map.HasDexRegisterMap(), (num_dex_registers != 0));
	CHECK_EQ(stack_map.HasInlineInfo(), (inlining_depth != 0));
	CHECK_EQ(code_info.GetInlineInfosOf(stack_map).size(), inlining_depth);
	});
	}
	}

	void StackMapStream::BeginInlineInfoEntry(ArtMethod* method,
	uint32_t dex_pc,
	uint32_t num_dex_registers,
	const DexFile* outer_dex_file) {
	DCHECK(in_stack_map_) << "Call BeginStackMapEntry first";
	DCHECK(!in_inline_info_) << "Mismatched Begin/End calls";
	in_inline_info_ = true;
	DCHECK_EQ(expected_num_dex_registers_, current_dex_registers_.size());

	expected_num_dex_registers_ += num_dex_registers;

	BitTableBuilder<InlineInfo>::Entry entry;
	entry[InlineInfo::kIsLast] = InlineInfo::kMore;
	entry[InlineInfo::kDexPc] = dex_pc;
	entry[InlineInfo::kNumberOfDexRegisters] = static_cast<uint32_t>(expected_num_dex_registers_);
	if (EncodeArtMethodInInlineInfo(method)) {
	entry[InlineInfo::kArtMethodHi] = High32Bits(reinterpret_cast<uintptr_t>(method));
	entry[InlineInfo::kArtMethodLo] = Low32Bits(reinterpret_cast<uintptr_t>(method));
	} else {
	if (dex_pc != static_cast<uint32_t>(-1) && kIsDebugBuild) {
	ScopedObjectAccess soa(Thread::Current());
	DCHECK(IsSameDexFile(outer_dex_file, method->GetDexFile()));
	}
	uint32_t dex_method_index = method->GetDexMethodIndex();
	entry[InlineInfo::kMethodInfoIndex] = method_infos_.Dedup({dex_method_index});
	}
	current_inline_infos_.push_back(entry);

	if (kVerifyStackMaps) {
	size_t stack_map_index = stack_maps_.size();
	size_t depth = current_inline_infos_.size() - 1;
	dchecks_.emplace_back([=](const CodeInfo& code_info) {
	StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
	InlineInfo inline_info = code_info.GetInlineInfosOf(stack_map)[depth];
	CHECK_EQ(inline_info.GetDexPc(), dex_pc);
	bool encode_art_method = EncodeArtMethodInInlineInfo(method);
	CHECK_EQ(inline_info.EncodesArtMethod(), encode_art_method);
	if (encode_art_method) {
	CHECK_EQ(inline_info.GetArtMethod(), method);
	} else {
	CHECK_EQ(code_info.GetMethodIndexOf(inline_info), method->GetDexMethodIndex());
	}
	});
	}
	}

	void StackMapStream::EndInlineInfoEntry() {
	DCHECK(in_inline_info_) << "Mismatched Begin/End calls";
	in_inline_info_ = false;
	DCHECK_EQ(expected_num_dex_registers_, current_dex_registers_.size());
	}

	// Create delta-compressed dex register map based on the current list of DexRegisterLocations.
	// All dex registers for a stack map are concatenated - inlined registers are just appended.
	void StackMapStream::CreateDexRegisterMap() {
	// These are fields rather than local variables so that we can reuse the reserved memory.
	temp_dex_register_mask_.ClearAllBits();
	temp_dex_register_map_.clear();

	// Ensure that the arrays that hold previous state are big enough to be safely indexed below.
	if (previous_dex_registers_.size() < current_dex_registers_.size()) {
	previous_dex_registers_.resize(current_dex_registers_.size(), DexRegisterLocation::None());
	dex_register_timestamp_.resize(current_dex_registers_.size(), 0u);
	}

	// Set bit in the mask for each register that has been changed since the previous stack map.
	// Modified registers are stored in the catalogue and the catalogue index added to the list.
	for (size_t i = 0; i < current_dex_registers_.size(); i++) {
	DexRegisterLocation reg = current_dex_registers_[i];
	// Distance is difference between this index and the index of last modification.
	uint32_t distance = stack_maps_.size() - dex_register_timestamp_[i];
	if (previous_dex_registers_[i] != reg \|\| distance > kMaxDexRegisterMapSearchDistance) {
	BitTableBuilder<DexRegisterInfo>::Entry entry;
	entry[DexRegisterInfo::kKind] = static_cast<uint32_t>(reg.GetKind());
	entry[DexRegisterInfo::kPackedValue] =
	DexRegisterInfo::PackValue(reg.GetKind(), reg.GetValue());
	uint32_t index = reg.IsLive() ? dex_register_catalog_.Dedup(&entry) : kNoValue;
	temp_dex_register_mask_.SetBit(i);
	temp_dex_register_map_.push_back({index});
	previous_dex_registers_[i] = reg;
	dex_register_timestamp_[i] = stack_maps_.size();
	}
	}

	// Set the mask and map for the current StackMap (which includes inlined registers).
	if (temp_dex_register_mask_.GetNumberOfBits() != 0) {
	current_stack_map_[StackMap::kDexRegisterMaskIndex] =
	dex_register_masks_.Dedup(temp_dex_register_mask_.GetRawStorage(),
	temp_dex_register_mask_.GetNumberOfBits());
	}
	if (!current_dex_registers_.empty()) {
	current_stack_map_[StackMap::kDexRegisterMapIndex] =
	dex_register_maps_.Dedup(temp_dex_register_map_.data(),
	temp_dex_register_map_.size());
	}

	if (kVerifyStackMaps) {
	size_t stack_map_index = stack_maps_.size();
	// We need to make copy of the current registers for later (when the check is run).
	auto expected_dex_registers = std::make_shared<dchecked_vector<DexRegisterLocation>>(
	current_dex_registers_.begin(), current_dex_registers_.end());
	dchecks_.emplace_back([=](const CodeInfo& code_info) {
	StackMap stack_map = code_info.GetStackMapAt(stack_map_index);
	uint32_t expected_reg = 0;
	for (DexRegisterLocation reg : code_info.GetDexRegisterMapOf(stack_map)) {
	CHECK_EQ((*expected_dex_registers)[expected_reg++], reg);
	}
	for (InlineInfo inline_info : code_info.GetInlineInfosOf(stack_map)) {
	DexRegisterMap map = code_info.GetInlineDexRegisterMapOf(stack_map, inline_info);
	for (DexRegisterLocation reg : map) {
	CHECK_EQ((*expected_dex_registers)[expected_reg++], reg);
	}
	}
	CHECK_EQ(expected_reg, expected_dex_registers->size());
	});
	}
	}

	ScopedArenaVector<uint8_t> StackMapStream::Encode() {
	DCHECK(in_stack_map_ == false) << "Mismatched Begin/End calls";
	DCHECK(in_inline_info_ == false) << "Mismatched Begin/End calls";

	uint32_t flags = (inline_infos_.size() > 0) ? CodeInfo::kHasInlineInfo : 0;
	uint32_t bit_table_flags = 0;
	ForEachBitTable([&bit_table_flags](size_t i, auto bit_table) {
	if (bit_table->size() != 0) { // Record which bit-tables are stored.
	bit_table_flags \|= 1 << i;
	}
	});

	ScopedArenaVector<uint8_t> buffer(allocator_->Adapter(kArenaAllocStackMapStream));
	BitMemoryWriter<ScopedArenaVector<uint8_t>> out(&buffer);
	out.WriteInterleavedVarints(std::array<uint32_t, CodeInfo::kNumHeaders>{
	flags,
	packed_frame_size_,
	core_spill_mask_,
	fp_spill_mask_,
	num_dex_registers_,
	bit_table_flags,
	});
	ForEachBitTable([&out](size_t, auto bit_table) {
	if (bit_table->size() != 0) { // Skip empty bit-tables.
	bit_table->Encode(out);
	}
	});

	// Verify that we can load the CodeInfo and check some essentials.
	size_t number_of_read_bits;
	CodeInfo code_info(buffer.data(), &number_of_read_bits);
	CHECK_EQ(number_of_read_bits, out.NumberOfWrittenBits());
	CHECK_EQ(code_info.GetNumberOfStackMaps(), stack_maps_.size());

	// Verify all written data (usually only in debug builds).
	if (kVerifyStackMaps) {
	for (const auto& dcheck : dchecks_) {
	dcheck(code_info);
	}
	}

	return buffer;
	}

	} // namespace art