src/trace_processor/util/profile_builder.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2022 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 "src/trace_processor/util/profile_builder.h"
 #include <algorithm>
 #include <cstdint>
 #include <deque>
 #include <iostream>
 #include <iterator>
 #include <optional>
 #include <vector>

 #include "perfetto/base/logging.h"
 #include "perfetto/ext/base/string_utils.h"
 #include "perfetto/ext/base/string_view.h"
 #include "perfetto/ext/trace_processor/demangle.h"
 #include "protos/third_party/pprof/profile.pbzero.h"
 #include "src/trace_processor/containers/null_term_string_view.h"
 #include "src/trace_processor/containers/string_pool.h"
 #include "src/trace_processor/storage/trace_storage.h"
 #include "src/trace_processor/types/trace_processor_context.h"
 #include "src/trace_processor/util/annotated_callsites.h"

 namespace perfetto {
 namespace trace_processor {
 namespace {

 using protos::pbzero::Stack;
 using third_party::perftools::profiles::pbzero::Profile;
 using third_party::perftools::profiles::pbzero::Sample;

 base::StringView ToString(CallsiteAnnotation annotation) {
   switch (annotation) {
     case CallsiteAnnotation::kNone:
       return "";
     case CallsiteAnnotation::kArtAot:
       return "aot";
     case CallsiteAnnotation::kArtInterpreted:
       return "interp";
     case CallsiteAnnotation::kArtJit:
       return "jit";
     case CallsiteAnnotation::kCommonFrame:
       return "common-frame";
     case CallsiteAnnotation::kCommonFrameInterp:
       return "common-frame-interp";
   }
   PERFETTO_FATAL("For GCC");
 }

 }  // namespace

 GProfileBuilder::StringTable::StringTable(
     protozero::HeapBuffered<third_party::perftools::profiles::pbzero::Profile>*
         result,
     const StringPool* string_pool)
     : string_pool_(*string_pool), result_(*result) {
   // String at index 0 of the string table must be the empty string (see
   // profile.proto)
   int64_t empty_index = WriteString("");
   PERFETTO_CHECK(empty_index == kEmptyStringIndex);
 }

 int64_t GProfileBuilder::StringTable::InternString(base::StringView str) {
   if (str.empty()) {
     return kEmptyStringIndex;
   }
   auto hash = str.Hash();
   auto it = seen_strings_.find(hash);
   if (it != seen_strings_.end()) {
     return it->second;
   }

   auto pool_id = string_pool_.GetId(str);
   int64_t index = pool_id ? InternString(*pool_id) : WriteString(str);

   seen_strings_.insert({hash, index});
   return index;
 }

 int64_t GProfileBuilder::StringTable::InternString(
     StringPool::Id string_pool_id) {
   auto it = seen_string_pool_ids_.find(string_pool_id);
   if (it != seen_string_pool_ids_.end()) {
     return it->second;
   }

   NullTermStringView str = string_pool_.Get(string_pool_id);

   int64_t index = str.empty() ? kEmptyStringIndex : WriteString(str);
   seen_string_pool_ids_.insert({string_pool_id, index});
   return index;
 }

 int64_t GProfileBuilder::StringTable::GetAnnotatedString(
     StringPool::Id str,
     CallsiteAnnotation annotation) {
   if (str.is_null() || annotation == CallsiteAnnotation::kNone) {
     return InternString(str);
   }
   return GetAnnotatedString(string_pool_.Get(str), annotation);
 }

 int64_t GProfileBuilder::StringTable::GetAnnotatedString(
     base::StringView str,
     CallsiteAnnotation annotation) {
   if (str.empty() || annotation == CallsiteAnnotation::kNone) {
     return InternString(str);
   }
   return InternString(base::StringView(
       str.ToStdString() + " [" + ToString(annotation).ToStdString() + "]"));
 }

 int64_t GProfileBuilder::StringTable::WriteString(base::StringView str) {
   result_->add_string_table(str.data(), str.size());
   return next_index_++;
 }

 GProfileBuilder::MappingKey::MappingKey(
     const tables::StackProfileMappingTable::ConstRowReference& mapping,
     StringTable& string_table) {
   size = static_cast<uint64_t>(mapping.end() - mapping.start());
   file_offset = static_cast<uint64_t>(mapping.exact_offset());
   build_id_or_filename = string_table.InternString(mapping.build_id());
   if (build_id_or_filename == kEmptyStringIndex) {
     build_id_or_filename = string_table.InternString(mapping.name());
   }
 }

 GProfileBuilder::Mapping::Mapping(
     const tables::StackProfileMappingTable::ConstRowReference& mapping,
     const StringPool& string_pool,
     StringTable& string_table)
     : memory_start(static_cast<uint64_t>(mapping.start())),
       memory_limit(static_cast<uint64_t>(mapping.end())),
       file_offset(static_cast<uint64_t>(mapping.exact_offset())),
       filename(string_table.InternString(mapping.name())),
       build_id(string_table.InternString(mapping.build_id())),
       filename_str(string_pool.Get(mapping.name()).ToStdString()) {}

 // Do some very basic scoring.
 int64_t GProfileBuilder::Mapping::ComputeMainBinaryScore() const {
   constexpr const char* kBadSuffixes[] = {".so"};
   constexpr const char* kBadPrefixes[] = {"/apex", "/system", "/[", "["};

   int64_t score = 0;
   if (build_id != kEmptyStringIndex) {
     score += 10;
   }

   if (filename != kEmptyStringIndex) {
     score += 10;
   }

   if (debug_info.has_functions) {
     score += 10;
   }
   if (debug_info.has_filenames) {
     score += 10;
   }
   if (debug_info.has_line_numbers) {
     score += 10;
   }
   if (debug_info.has_inline_frames) {
     score += 10;
   }

   if (memory_limit == memory_start) {
     score -= 1000;
   }

   for (const char* suffix : kBadSuffixes) {
     if (base::EndsWith(filename_str, suffix)) {
       score -= 1000;
       break;
     }
   }

   for (const char* prefix : kBadPrefixes) {
     if (base::StartsWith(filename_str, prefix)) {
       score -= 1000;
       break;
     }
   }

   return score;
 }

 bool GProfileBuilder::SampleAggregator::AddSample(
     const protozero::PackedVarInt& location_ids,
     const std::vector<int64_t>& values) {
   SerializedLocationId key(location_ids.data(),
                            location_ids.data() + location_ids.size());
   std::vector<int64_t>* agg_values = samples_.Find(key);
   if (!agg_values) {
     samples_.Insert(std::move(key), values);
     return true;
   }
   // All samples must have the same number of values.
   if (values.size() != agg_values->size()) {
     return false;
   }
   std::transform(values.begin(), values.end(), agg_values->begin(),
                  agg_values->begin(), std::plus<int64_t>());
   return true;
 }

 void GProfileBuilder::SampleAggregator::WriteTo(Profile& profile) {
   protozero::PackedVarInt values;
   for (auto it = samples_.GetIterator(); it; ++it) {
     values.Reset();
     for (int64_t value : it.value()) {
       values.Append(value);
     }
     Sample* sample = profile.add_sample();
     sample->set_value(values);
     // Map key is the serialized varint. Just append the bytes.
     sample->AppendBytes(Sample::kLocationIdFieldNumber, it.key().data(),
                         it.key().size());
   }
 }

 GProfileBuilder::GProfileBuilder(const TraceProcessorContext* context,
                                  const std::vector<ValueType>& sample_types)
     : context_(*context),
       string_table_(&result_, &context->storage->string_pool()),
       annotations_(context) {
   // Make sure the empty function always gets id 0 which will be ignored
   // when writing the proto file.
   functions_.insert(
       {Function{kEmptyStringIndex, kEmptyStringIndex, kEmptyStringIndex},
        kNullFunctionId});
   WriteSampleTypes(sample_types);
 }

 GProfileBuilder::~GProfileBuilder() = default;

 void GProfileBuilder::WriteSampleTypes(
     const std::vector<ValueType>& sample_types) {
   for (const auto& value_type : sample_types) {
     // Write strings first
     int64_t type =
         string_table_.InternString(base::StringView(value_type.type));
     int64_t unit =
         string_table_.InternString(base::StringView(value_type.unit));
     // Add message later, remember protozero does not allow you to
     // interleave these write calls.
     auto* sample_type = result_->add_sample_type();
     sample_type->set_type(type);
     sample_type->set_unit(unit);
   }
 }

 bool GProfileBuilder::AddSample(const Stack::Decoder& stack,
                                 const std::vector<int64_t>& values) {
   PERFETTO_CHECK(!finalized_);

   auto it = stack.entries();
   if (!it) {
     return true;
   }

   auto next = it;
   ++next;
   if (!next) {
     Stack::Entry::Decoder entry(it->as_bytes());
     if (entry.has_callsite_id() || entry.has_annotated_callsite_id()) {
       bool annotated = entry.has_annotated_callsite_id();
       uint32_t callsite_id = entry.has_callsite_id()
                                  ? entry.callsite_id()
                                  : entry.annotated_callsite_id();
       return samples_.AddSample(
           GetLocationIdsForCallsite(CallsiteId(callsite_id), annotated),
           values);
     }
   }

   // Note pprof orders the stacks leafs first. That is also the ordering
   // StackBlob uses for entries
   protozero::PackedVarInt location_ids;
   for (; it; ++it) {
     Stack::Entry::Decoder entry(it->as_bytes());
     if (entry.has_name()) {
       location_ids.Append(
           WriteFakeLocationIfNeeded(entry.name().ToStdString()));
     } else if (entry.has_callsite_id() || entry.has_annotated_callsite_id()) {
       bool annotated = entry.has_annotated_callsite_id();
       uint32_t callsite_id = entry.has_callsite_id()
                                  ? entry.callsite_id()
                                  : entry.annotated_callsite_id();
       const protozero::PackedVarInt& ids =
           GetLocationIdsForCallsite(CallsiteId(callsite_id), annotated);
       for (auto* p = ids.data(); p < ids.data() + ids.size();) {
         uint64_t location_id;
         p = protozero::proto_utils::ParseVarInt(p, ids.data() + ids.size(),
                                                 &location_id);
         location_ids.Append(location_id);
       }
     } else if (entry.has_frame_id()) {
       location_ids.Append(WriteLocationIfNeeded(FrameId(entry.frame_id()),
                                                 CallsiteAnnotation::kNone));
     }
   }
   return samples_.AddSample(location_ids, values);
 }

 void GProfileBuilder::Finalize() {
   if (finalized_) {
     return;
   }
   WriteMappings();
   WriteFunctions();
   WriteLocations();
   samples_.WriteTo(*result_.get());
   finalized_ = true;
 }

 std::string GProfileBuilder::Build() {
   Finalize();
   return result_.SerializeAsString();
 }

 const protozero::PackedVarInt& GProfileBuilder::GetLocationIdsForCallsite(
     const CallsiteId& callsite_id,
     bool annotated) {
   auto it = cached_location_ids_.find({callsite_id, annotated});
   if (it != cached_location_ids_.end()) {
     return it->second;
   }

   protozero::PackedVarInt& location_ids =
       cached_location_ids_[{callsite_id, annotated}];

   const auto& cs_table = context_.storage->stack_profile_callsite_table();

   std::optional<tables::StackProfileCallsiteTable::ConstRowReference>
       start_ref = cs_table.FindById(callsite_id);
   if (!start_ref) {
     return location_ids;
   }

   location_ids.Append(WriteLocationIfNeeded(
       start_ref->frame_id(), annotated ? annotations_.GetAnnotation(*start_ref)
                                        : CallsiteAnnotation::kNone));

   std::optional<CallsiteId> parent_id = start_ref->parent_id();
   while (parent_id) {
     auto parent_ref = cs_table.FindById(*parent_id);
     location_ids.Append(WriteLocationIfNeeded(
         parent_ref->frame_id(), annotated
                                     ? annotations_.GetAnnotation(*parent_ref)
                                     : CallsiteAnnotation::kNone));
     parent_id = parent_ref->parent_id();
   }

   return location_ids;
 }

 uint64_t GProfileBuilder::WriteLocationIfNeeded(FrameId frame_id,
                                                 CallsiteAnnotation annotation) {
   AnnotatedFrameId key{frame_id, annotation};
   auto it = seen_locations_.find(key);
   if (it != seen_locations_.end()) {
     return it->second;
   }

   auto& frames = context_.storage->stack_profile_frame_table();
   auto frame = *frames.FindById(key.frame_id);

   const auto& mappings = context_.storage->stack_profile_mapping_table();
   auto mapping = *mappings.FindById(frame.mapping());
   uint64_t mapping_id = WriteMappingIfNeeded(mapping);

   uint64_t& id =
       locations_[Location{mapping_id, static_cast<uint64_t>(frame.rel_pc()),
                           GetLines(frame, key.annotation, mapping_id)}];

   if (id == 0) {
     id = locations_.size();
   }

   seen_locations_.insert({key, id});

   return id;
 }

 uint64_t GProfileBuilder::WriteFakeLocationIfNeeded(const std::string& name) {
   int64_t name_id = string_table_.InternString(base::StringView(name));
   auto it = seen_fake_locations_.find(name_id);
   if (it != seen_fake_locations_.end()) {
     return it->second;
   }

   uint64_t& id =
       locations_[Location{0, 0, {{WriteFakeFunctionIfNeeded(name_id), 0}}}];

   if (id == 0) {
     id = locations_.size();
   }

   seen_fake_locations_.insert({name_id, id});

   return id;
 }

 void GProfileBuilder::WriteLocations() {
   for (const auto& entry : locations_) {
     auto* location = result_->add_location();
     location->set_id(entry.second);
     location->set_mapping_id(entry.first.mapping_id);
     if (entry.first.mapping_id != 0) {
       location->set_address(entry.first.rel_pc +
                             GetMapping(entry.first.mapping_id).memory_start);
     }
     for (const Line& line : entry.first.lines) {
       auto* l = location->add_line();
       l->set_function_id(line.function_id);
       if (line.line != 0) {
         l->set_line(line.line);
       }
     }
   }
 }

 std::vector<GProfileBuilder::Line> GProfileBuilder::GetLines(
     const tables::StackProfileFrameTable::ConstRowReference& frame,
     CallsiteAnnotation annotation,
     uint64_t mapping_id) {
   std::vector<Line> lines =
       GetLinesForSymbolSetId(frame.symbol_set_id(), annotation, mapping_id);
   if (!lines.empty()) {
     return lines;
   }

   if (uint64_t function_id =
           WriteFunctionIfNeeded(frame, annotation, mapping_id);
       function_id != kNullFunctionId) {
     lines.push_back({function_id, 0});
   }

   return lines;
 }

 std::vector<GProfileBuilder::Line> GProfileBuilder::GetLinesForSymbolSetId(
     std::optional<uint32_t> symbol_set_id,
     CallsiteAnnotation annotation,
     uint64_t mapping_id) {
   if (!symbol_set_id) {
     return {};
   }

   auto& symbols = context_.storage->symbol_table();

   using RowRef =
       perfetto::trace_processor::tables::SymbolTable::ConstRowReference;
   std::vector<RowRef> symbol_set;
   Query q;
   q.constraints = {symbols.symbol_set_id().eq(*symbol_set_id)};
   for (auto it = symbols.FilterToIterator(q); it; ++it) {
     symbol_set.push_back(it.row_reference());
   }

   std::sort(symbol_set.begin(), symbol_set.end(),
             [](const RowRef& a, const RowRef& b) { return a.id() < b.id(); });

   std::vector<GProfileBuilder::Line> lines;
   for (const RowRef& symbol : symbol_set) {
     if (uint64_t function_id =
             WriteFunctionIfNeeded(symbol, annotation, mapping_id);
         function_id != kNullFunctionId) {
       lines.push_back({function_id, symbol.line_number().value_or(0)});
     }
   }

   GetMapping(mapping_id).debug_info.has_inline_frames = true;
   GetMapping(mapping_id).debug_info.has_line_numbers = true;

   return lines;
 }

 uint64_t GProfileBuilder::WriteFakeFunctionIfNeeded(int64_t name_id) {
   auto ins = functions_.insert(
       {Function{name_id, kEmptyStringIndex, kEmptyStringIndex},
        functions_.size() + 1});
   return ins.first->second;
 }

 uint64_t GProfileBuilder::WriteFunctionIfNeeded(
     const tables::SymbolTable::ConstRowReference& symbol,
     CallsiteAnnotation annotation,
     uint64_t mapping_id) {
   int64_t name = string_table_.GetAnnotatedString(symbol.name(), annotation);
   int64_t filename = symbol.source_file().has_value()
                          ? string_table_.InternString(*symbol.source_file())
                          : kEmptyStringIndex;

   auto ins = functions_.insert(
       {Function{name, kEmptyStringIndex, filename}, functions_.size() + 1});
   uint64_t id = ins.first->second;

   if (ins.second) {
     if (name != kEmptyStringIndex) {
       GetMapping(mapping_id).debug_info.has_functions = true;
     }
     if (filename != kEmptyStringIndex) {
       GetMapping(mapping_id).debug_info.has_filenames = true;
     }
   }

   return id;
 }

 int64_t GProfileBuilder::GetNameForFrame(
     const tables::StackProfileFrameTable::ConstRowReference& frame,
     CallsiteAnnotation annotation) {
   NullTermStringView system_name = context_.storage->GetString(frame.name());
   int64_t name = kEmptyStringIndex;
   if (frame.deobfuscated_name()) {
     name = string_table_.GetAnnotatedString(*frame.deobfuscated_name(),
                                             annotation);
   } else if (!system_name.empty()) {
     std::unique_ptr<char, base::FreeDeleter> demangled =
         demangle::Demangle(system_name.c_str());
     if (demangled) {
       name = string_table_.GetAnnotatedString(demangled.get(), annotation);
     } else {
       // demangling failed, expected if the name wasn't mangled. In any case
       // reuse the system_name as this is what UI will usually display.
       name = string_table_.GetAnnotatedString(frame.name(), annotation);
     }
   }
   return name;
 }

 int64_t GProfileBuilder::GetSystemNameForFrame(
     const tables::StackProfileFrameTable::ConstRowReference& frame) {
   return string_table_.InternString(frame.name());
 }

 uint64_t GProfileBuilder::WriteFunctionIfNeeded(
     const tables::StackProfileFrameTable::ConstRowReference& frame,
     CallsiteAnnotation annotation,
     uint64_t mapping_id) {
   AnnotatedFrameId key{frame.id(), annotation};
   auto it = seen_functions_.find(key);
   if (it != seen_functions_.end()) {
     return it->second;
   }

   auto ins = functions_.insert(
       {Function{GetNameForFrame(frame, annotation),
                 GetSystemNameForFrame(frame), kEmptyStringIndex},
        functions_.size() + 1});
   uint64_t id = ins.first->second;
   seen_functions_.insert({key, id});

   if (ins.second && (ins.first->first.name != kEmptyStringIndex ||
                      ins.first->first.system_name != kEmptyStringIndex)) {
     GetMapping(mapping_id).debug_info.has_functions = true;
   }

   return id;
 }

 void GProfileBuilder::WriteFunctions() {
   for (const auto& entry : functions_) {
     if (entry.second == kNullFunctionId) {
       continue;
     }
     auto* func = result_->add_function();
     func->set_id(entry.second);
     if (entry.first.name != 0) {
       func->set_name(entry.first.name);
     }
     if (entry.first.system_name != 0) {
       func->set_system_name(entry.first.system_name);
     }
     if (entry.first.filename != 0) {
       func->set_filename(entry.first.filename);
     }
   }
 }

 uint64_t GProfileBuilder::WriteMappingIfNeeded(
     const tables::StackProfileMappingTable::ConstRowReference& mapping_ref) {
   auto it = seen_mappings_.find(mapping_ref.id());
   if (it != seen_mappings_.end()) {
     return it->second;
   }

   auto ins = mapping_keys_.insert(
       {MappingKey(mapping_ref, string_table_), mapping_keys_.size() + 1});

   if (ins.second) {
     mappings_.push_back(
         Mapping(mapping_ref, context_.storage->string_pool(), string_table_));
   }

   return ins.first->second;
 }

 void GProfileBuilder::WriteMapping(uint64_t mapping_id) {
   const Mapping& mapping = GetMapping(mapping_id);
   auto m = result_->add_mapping();
   m->set_id(mapping_id);
   m->set_memory_start(mapping.memory_start);
   m->set_memory_limit(mapping.memory_limit);
   m->set_file_offset(mapping.file_offset);
   m->set_filename(mapping.filename);
   m->set_build_id(mapping.build_id);
   m->set_has_functions(mapping.debug_info.has_functions);
   m->set_has_filenames(mapping.debug_info.has_filenames);
   m->set_has_line_numbers(mapping.debug_info.has_line_numbers);
   m->set_has_inline_frames(mapping.debug_info.has_inline_frames);
 }

 void GProfileBuilder::WriteMappings() {
   // The convention in pprof files is to write the mapping for the main
   // binary first. So lets do just that.
   std::optional<uint64_t> main_mapping_id = GuessMainBinary();
   if (main_mapping_id) {
     WriteMapping(*main_mapping_id);
   }

   for (size_t i = 0; i < mappings_.size(); ++i) {
     uint64_t mapping_id = i + 1;
     if (main_mapping_id && *main_mapping_id == mapping_id) {
       continue;
     }
     WriteMapping(mapping_id);
   }
 }

 std::optional<uint64_t> GProfileBuilder::GuessMainBinary() const {
   std::vector<int64_t> mapping_scores;

   for (const auto& mapping : mappings_) {
     mapping_scores.push_back(mapping.ComputeMainBinaryScore());
   }

   auto it = std::max_element(mapping_scores.begin(), mapping_scores.end());

   if (it == mapping_scores.end()) {
     return std::nullopt;
   }

   return static_cast<uint64_t>(std::distance(mapping_scores.begin(), it) + 1);
 }

 }  // namespace trace_processor
 }  // namespace perfetto
	/*
	* Copyright (C) 2022 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 "src/trace_processor/util/profile_builder.h"
	#include <algorithm>
	#include <cstdint>
	#include <deque>
	#include <iostream>
	#include <iterator>
	#include <optional>
	#include <vector>

	#include "perfetto/base/logging.h"
	#include "perfetto/ext/base/string_utils.h"
	#include "perfetto/ext/base/string_view.h"
	#include "perfetto/ext/trace_processor/demangle.h"
	#include "protos/third_party/pprof/profile.pbzero.h"
	#include "src/trace_processor/containers/null_term_string_view.h"
	#include "src/trace_processor/containers/string_pool.h"
	#include "src/trace_processor/storage/trace_storage.h"
	#include "src/trace_processor/types/trace_processor_context.h"
	#include "src/trace_processor/util/annotated_callsites.h"

	namespace perfetto {
	namespace trace_processor {
	namespace {

	using protos::pbzero::Stack;
	using third_party::perftools::profiles::pbzero::Profile;
	using third_party::perftools::profiles::pbzero::Sample;

	base::StringView ToString(CallsiteAnnotation annotation) {
	switch (annotation) {
	case CallsiteAnnotation::kNone:
	return "";
	case CallsiteAnnotation::kArtAot:
	return "aot";
	case CallsiteAnnotation::kArtInterpreted:
	return "interp";
	case CallsiteAnnotation::kArtJit:
	return "jit";
	case CallsiteAnnotation::kCommonFrame:
	return "common-frame";
	case CallsiteAnnotation::kCommonFrameInterp:
	return "common-frame-interp";
	}
	PERFETTO_FATAL("For GCC");
	}

	} // namespace

	GProfileBuilder::StringTable::StringTable(
	protozero::HeapBuffered<third_party::perftools::profiles::pbzero::Profile>*
	result,
	const StringPool* string_pool)
	: string_pool_(string_pool), result_(result) {
	// String at index 0 of the string table must be the empty string (see
	// profile.proto)
	int64_t empty_index = WriteString("");
	PERFETTO_CHECK(empty_index == kEmptyStringIndex);
	}

	int64_t GProfileBuilder::StringTable::InternString(base::StringView str) {
	if (str.empty()) {
	return kEmptyStringIndex;
	}
	auto hash = str.Hash();
	auto it = seen_strings_.find(hash);
	if (it != seen_strings_.end()) {
	return it->second;
	}

	auto pool_id = string_pool_.GetId(str);
	int64_t index = pool_id ? InternString(*pool_id) : WriteString(str);

	seen_strings_.insert({hash, index});
	return index;
	}

	int64_t GProfileBuilder::StringTable::InternString(
	StringPool::Id string_pool_id) {
	auto it = seen_string_pool_ids_.find(string_pool_id);
	if (it != seen_string_pool_ids_.end()) {
	return it->second;
	}

	NullTermStringView str = string_pool_.Get(string_pool_id);

	int64_t index = str.empty() ? kEmptyStringIndex : WriteString(str);
	seen_string_pool_ids_.insert({string_pool_id, index});
	return index;
	}

	int64_t GProfileBuilder::StringTable::GetAnnotatedString(
	StringPool::Id str,
	CallsiteAnnotation annotation) {
	if (str.is_null() \|\| annotation == CallsiteAnnotation::kNone) {
	return InternString(str);
	}
	return GetAnnotatedString(string_pool_.Get(str), annotation);
	}

	int64_t GProfileBuilder::StringTable::GetAnnotatedString(
	base::StringView str,
	CallsiteAnnotation annotation) {
	if (str.empty() \|\| annotation == CallsiteAnnotation::kNone) {
	return InternString(str);
	}
	return InternString(base::StringView(
	str.ToStdString() + " [" + ToString(annotation).ToStdString() + "]"));
	}

	int64_t GProfileBuilder::StringTable::WriteString(base::StringView str) {
	result_->add_string_table(str.data(), str.size());
	return next_index_++;
	}

	GProfileBuilder::MappingKey::MappingKey(
	const tables::StackProfileMappingTable::ConstRowReference& mapping,
	StringTable& string_table) {
	size = static_cast<uint64_t>(mapping.end() - mapping.start());
	file_offset = static_cast<uint64_t>(mapping.exact_offset());
	build_id_or_filename = string_table.InternString(mapping.build_id());
	if (build_id_or_filename == kEmptyStringIndex) {
	build_id_or_filename = string_table.InternString(mapping.name());
	}
	}

	GProfileBuilder::Mapping::Mapping(
	const tables::StackProfileMappingTable::ConstRowReference& mapping,
	const StringPool& string_pool,
	StringTable& string_table)
	: memory_start(static_cast<uint64_t>(mapping.start())),
	memory_limit(static_cast<uint64_t>(mapping.end())),
	file_offset(static_cast<uint64_t>(mapping.exact_offset())),
	filename(string_table.InternString(mapping.name())),
	build_id(string_table.InternString(mapping.build_id())),
	filename_str(string_pool.Get(mapping.name()).ToStdString()) {}

	// Do some very basic scoring.
	int64_t GProfileBuilder::Mapping::ComputeMainBinaryScore() const {
	constexpr const char* kBadSuffixes[] = {".so"};
	constexpr const char* kBadPrefixes[] = {"/apex", "/system", "/[", "["};

	int64_t score = 0;
	if (build_id != kEmptyStringIndex) {
	score += 10;
	}

	if (filename != kEmptyStringIndex) {
	score += 10;
	}

	if (debug_info.has_functions) {
	score += 10;
	}
	if (debug_info.has_filenames) {
	score += 10;
	}
	if (debug_info.has_line_numbers) {
	score += 10;
	}
	if (debug_info.has_inline_frames) {
	score += 10;
	}

	if (memory_limit == memory_start) {
	score -= 1000;
	}

	for (const char* suffix : kBadSuffixes) {
	if (base::EndsWith(filename_str, suffix)) {
	score -= 1000;
	break;
	}
	}

	for (const char* prefix : kBadPrefixes) {
	if (base::StartsWith(filename_str, prefix)) {
	score -= 1000;
	break;
	}
	}

	return score;
	}

	bool GProfileBuilder::SampleAggregator::AddSample(
	const protozero::PackedVarInt& location_ids,
	const std::vector<int64_t>& values) {
	SerializedLocationId key(location_ids.data(),
	location_ids.data() + location_ids.size());
	std::vector<int64_t>* agg_values = samples_.Find(key);
	if (!agg_values) {
	samples_.Insert(std::move(key), values);
	return true;
	}
	// All samples must have the same number of values.
	if (values.size() != agg_values->size()) {
	return false;
	}
	std::transform(values.begin(), values.end(), agg_values->begin(),
	agg_values->begin(), std::plus<int64_t>());
	return true;
	}

	void GProfileBuilder::SampleAggregator::WriteTo(Profile& profile) {
	protozero::PackedVarInt values;
	for (auto it = samples_.GetIterator(); it; ++it) {
	values.Reset();
	for (int64_t value : it.value()) {
	values.Append(value);
	}
	Sample* sample = profile.add_sample();
	sample->set_value(values);
	// Map key is the serialized varint. Just append the bytes.
	sample->AppendBytes(Sample::kLocationIdFieldNumber, it.key().data(),
	it.key().size());
	}
	}

	GProfileBuilder::GProfileBuilder(const TraceProcessorContext* context,
	const std::vector<ValueType>& sample_types)
	: context_(*context),
	string_table_(&result_, &context->storage->string_pool()),
	annotations_(context) {
	// Make sure the empty function always gets id 0 which will be ignored
	// when writing the proto file.
	functions_.insert(
	{Function{kEmptyStringIndex, kEmptyStringIndex, kEmptyStringIndex},
	kNullFunctionId});
	WriteSampleTypes(sample_types);
	}

	GProfileBuilder::~GProfileBuilder() = default;

	void GProfileBuilder::WriteSampleTypes(
	const std::vector<ValueType>& sample_types) {
	for (const auto& value_type : sample_types) {
	// Write strings first
	int64_t type =
	string_table_.InternString(base::StringView(value_type.type));
	int64_t unit =
	string_table_.InternString(base::StringView(value_type.unit));
	// Add message later, remember protozero does not allow you to
	// interleave these write calls.
	auto* sample_type = result_->add_sample_type();
	sample_type->set_type(type);
	sample_type->set_unit(unit);
	}
	}

	bool GProfileBuilder::AddSample(const Stack::Decoder& stack,
	const std::vector<int64_t>& values) {
	PERFETTO_CHECK(!finalized_);

	auto it = stack.entries();
	if (!it) {
	return true;
	}

	auto next = it;
	++next;
	if (!next) {
	Stack::Entry::Decoder entry(it->as_bytes());
	if (entry.has_callsite_id() \|\| entry.has_annotated_callsite_id()) {
	bool annotated = entry.has_annotated_callsite_id();
	uint32_t callsite_id = entry.has_callsite_id()
	? entry.callsite_id()
	: entry.annotated_callsite_id();
	return samples_.AddSample(
	GetLocationIdsForCallsite(CallsiteId(callsite_id), annotated),
	values);
	}
	}

	// Note pprof orders the stacks leafs first. That is also the ordering
	// StackBlob uses for entries
	protozero::PackedVarInt location_ids;
	for (; it; ++it) {
	Stack::Entry::Decoder entry(it->as_bytes());
	if (entry.has_name()) {
	location_ids.Append(
	WriteFakeLocationIfNeeded(entry.name().ToStdString()));
	} else if (entry.has_callsite_id() \|\| entry.has_annotated_callsite_id()) {
	bool annotated = entry.has_annotated_callsite_id();
	uint32_t callsite_id = entry.has_callsite_id()
	? entry.callsite_id()
	: entry.annotated_callsite_id();
	const protozero::PackedVarInt& ids =
	GetLocationIdsForCallsite(CallsiteId(callsite_id), annotated);
	for (auto* p = ids.data(); p < ids.data() + ids.size();) {
	uint64_t location_id;
	p = protozero::proto_utils::ParseVarInt(p, ids.data() + ids.size(),
	&location_id);
	location_ids.Append(location_id);
	}
	} else if (entry.has_frame_id()) {
	location_ids.Append(WriteLocationIfNeeded(FrameId(entry.frame_id()),
	CallsiteAnnotation::kNone));
	}
	}
	return samples_.AddSample(location_ids, values);
	}

	void GProfileBuilder::Finalize() {
	if (finalized_) {
	return;
	}
	WriteMappings();
	WriteFunctions();
	WriteLocations();
	samples_.WriteTo(*result_.get());
	finalized_ = true;
	}

	std::string GProfileBuilder::Build() {
	Finalize();
	return result_.SerializeAsString();
	}

	const protozero::PackedVarInt& GProfileBuilder::GetLocationIdsForCallsite(
	const CallsiteId& callsite_id,
	bool annotated) {
	auto it = cached_location_ids_.find({callsite_id, annotated});
	if (it != cached_location_ids_.end()) {
	return it->second;
	}

	protozero::PackedVarInt& location_ids =
	cached_location_ids_[{callsite_id, annotated}];

	const auto& cs_table = context_.storage->stack_profile_callsite_table();

	std::optional<tables::StackProfileCallsiteTable::ConstRowReference>
	start_ref = cs_table.FindById(callsite_id);
	if (!start_ref) {
	return location_ids;
	}

	location_ids.Append(WriteLocationIfNeeded(
	start_ref->frame_id(), annotated ? annotations_.GetAnnotation(*start_ref)
	: CallsiteAnnotation::kNone));

	std::optional<CallsiteId> parent_id = start_ref->parent_id();
	while (parent_id) {
	auto parent_ref = cs_table.FindById(*parent_id);
	location_ids.Append(WriteLocationIfNeeded(
	parent_ref->frame_id(), annotated
	? annotations_.GetAnnotation(*parent_ref)
	: CallsiteAnnotation::kNone));
	parent_id = parent_ref->parent_id();
	}

	return location_ids;
	}

	uint64_t GProfileBuilder::WriteLocationIfNeeded(FrameId frame_id,
	CallsiteAnnotation annotation) {
	AnnotatedFrameId key{frame_id, annotation};
	auto it = seen_locations_.find(key);
	if (it != seen_locations_.end()) {
	return it->second;
	}

	auto& frames = context_.storage->stack_profile_frame_table();
	auto frame = *frames.FindById(key.frame_id);

	const auto& mappings = context_.storage->stack_profile_mapping_table();
	auto mapping = *mappings.FindById(frame.mapping());
	uint64_t mapping_id = WriteMappingIfNeeded(mapping);

	uint64_t& id =
	locations_[Location{mapping_id, static_cast<uint64_t>(frame.rel_pc()),
	GetLines(frame, key.annotation, mapping_id)}];

	if (id == 0) {
	id = locations_.size();
	}

	seen_locations_.insert({key, id});

	return id;
	}

	uint64_t GProfileBuilder::WriteFakeLocationIfNeeded(const std::string& name) {
	int64_t name_id = string_table_.InternString(base::StringView(name));
	auto it = seen_fake_locations_.find(name_id);
	if (it != seen_fake_locations_.end()) {
	return it->second;
	}

	uint64_t& id =
	locations_[Location{0, 0, {{WriteFakeFunctionIfNeeded(name_id), 0}}}];

	if (id == 0) {
	id = locations_.size();
	}

	seen_fake_locations_.insert({name_id, id});

	return id;
	}

	void GProfileBuilder::WriteLocations() {
	for (const auto& entry : locations_) {
	auto* location = result_->add_location();
	location->set_id(entry.second);
	location->set_mapping_id(entry.first.mapping_id);
	if (entry.first.mapping_id != 0) {
	location->set_address(entry.first.rel_pc +
	GetMapping(entry.first.mapping_id).memory_start);
	}
	for (const Line& line : entry.first.lines) {
	auto* l = location->add_line();
	l->set_function_id(line.function_id);
	if (line.line != 0) {
	l->set_line(line.line);
	}
	}
	}
	}

	std::vector<GProfileBuilder::Line> GProfileBuilder::GetLines(
	const tables::StackProfileFrameTable::ConstRowReference& frame,
	CallsiteAnnotation annotation,
	uint64_t mapping_id) {
	std::vector<Line> lines =
	GetLinesForSymbolSetId(frame.symbol_set_id(), annotation, mapping_id);
	if (!lines.empty()) {
	return lines;
	}

	if (uint64_t function_id =
	WriteFunctionIfNeeded(frame, annotation, mapping_id);
	function_id != kNullFunctionId) {
	lines.push_back({function_id, 0});
	}

	return lines;
	}

	std::vector<GProfileBuilder::Line> GProfileBuilder::GetLinesForSymbolSetId(
	std::optional<uint32_t> symbol_set_id,
	CallsiteAnnotation annotation,
	uint64_t mapping_id) {
	if (!symbol_set_id) {
	return {};
	}

	auto& symbols = context_.storage->symbol_table();

	using RowRef =
	perfetto::trace_processor::tables::SymbolTable::ConstRowReference;
	std::vector<RowRef> symbol_set;
	Query q;
	q.constraints = {symbols.symbol_set_id().eq(*symbol_set_id)};
	for (auto it = symbols.FilterToIterator(q); it; ++it) {
	symbol_set.push_back(it.row_reference());
	}

	std::sort(symbol_set.begin(), symbol_set.end(),
	[](const RowRef& a, const RowRef& b) { return a.id() < b.id(); });

	std::vector<GProfileBuilder::Line> lines;
	for (const RowRef& symbol : symbol_set) {
	if (uint64_t function_id =
	WriteFunctionIfNeeded(symbol, annotation, mapping_id);
	function_id != kNullFunctionId) {
	lines.push_back({function_id, symbol.line_number().value_or(0)});
	}
	}

	GetMapping(mapping_id).debug_info.has_inline_frames = true;
	GetMapping(mapping_id).debug_info.has_line_numbers = true;

	return lines;
	}

	uint64_t GProfileBuilder::WriteFakeFunctionIfNeeded(int64_t name_id) {
	auto ins = functions_.insert(
	{Function{name_id, kEmptyStringIndex, kEmptyStringIndex},
	functions_.size() + 1});
	return ins.first->second;
	}

	uint64_t GProfileBuilder::WriteFunctionIfNeeded(
	const tables::SymbolTable::ConstRowReference& symbol,
	CallsiteAnnotation annotation,
	uint64_t mapping_id) {
	int64_t name = string_table_.GetAnnotatedString(symbol.name(), annotation);
	int64_t filename = symbol.source_file().has_value()
	? string_table_.InternString(*symbol.source_file())
	: kEmptyStringIndex;

	auto ins = functions_.insert(
	{Function{name, kEmptyStringIndex, filename}, functions_.size() + 1});
	uint64_t id = ins.first->second;

	if (ins.second) {
	if (name != kEmptyStringIndex) {
	GetMapping(mapping_id).debug_info.has_functions = true;
	}
	if (filename != kEmptyStringIndex) {
	GetMapping(mapping_id).debug_info.has_filenames = true;
	}
	}

	return id;
	}

	int64_t GProfileBuilder::GetNameForFrame(
	const tables::StackProfileFrameTable::ConstRowReference& frame,
	CallsiteAnnotation annotation) {
	NullTermStringView system_name = context_.storage->GetString(frame.name());
	int64_t name = kEmptyStringIndex;
	if (frame.deobfuscated_name()) {
	name = string_table_.GetAnnotatedString(*frame.deobfuscated_name(),
	annotation);
	} else if (!system_name.empty()) {
	std::unique_ptr<char, base::FreeDeleter> demangled =
	demangle::Demangle(system_name.c_str());
	if (demangled) {
	name = string_table_.GetAnnotatedString(demangled.get(), annotation);
	} else {
	// demangling failed, expected if the name wasn't mangled. In any case
	// reuse the system_name as this is what UI will usually display.
	name = string_table_.GetAnnotatedString(frame.name(), annotation);
	}
	}
	return name;
	}

	int64_t GProfileBuilder::GetSystemNameForFrame(
	const tables::StackProfileFrameTable::ConstRowReference& frame) {
	return string_table_.InternString(frame.name());
	}

	uint64_t GProfileBuilder::WriteFunctionIfNeeded(
	const tables::StackProfileFrameTable::ConstRowReference& frame,
	CallsiteAnnotation annotation,
	uint64_t mapping_id) {
	AnnotatedFrameId key{frame.id(), annotation};
	auto it = seen_functions_.find(key);
	if (it != seen_functions_.end()) {
	return it->second;
	}

	auto ins = functions_.insert(
	{Function{GetNameForFrame(frame, annotation),
	GetSystemNameForFrame(frame), kEmptyStringIndex},
	functions_.size() + 1});
	uint64_t id = ins.first->second;
	seen_functions_.insert({key, id});

	if (ins.second && (ins.first->first.name != kEmptyStringIndex \|\|
	ins.first->first.system_name != kEmptyStringIndex)) {
	GetMapping(mapping_id).debug_info.has_functions = true;
	}

	return id;
	}

	void GProfileBuilder::WriteFunctions() {
	for (const auto& entry : functions_) {
	if (entry.second == kNullFunctionId) {
	continue;
	}
	auto* func = result_->add_function();
	func->set_id(entry.second);
	if (entry.first.name != 0) {
	func->set_name(entry.first.name);
	}
	if (entry.first.system_name != 0) {
	func->set_system_name(entry.first.system_name);
	}
	if (entry.first.filename != 0) {
	func->set_filename(entry.first.filename);
	}
	}
	}

	uint64_t GProfileBuilder::WriteMappingIfNeeded(
	const tables::StackProfileMappingTable::ConstRowReference& mapping_ref) {
	auto it = seen_mappings_.find(mapping_ref.id());
	if (it != seen_mappings_.end()) {
	return it->second;
	}

	auto ins = mapping_keys_.insert(
	{MappingKey(mapping_ref, string_table_), mapping_keys_.size() + 1});

	if (ins.second) {
	mappings_.push_back(
	Mapping(mapping_ref, context_.storage->string_pool(), string_table_));
	}

	return ins.first->second;
	}

	void GProfileBuilder::WriteMapping(uint64_t mapping_id) {
	const Mapping& mapping = GetMapping(mapping_id);
	auto m = result_->add_mapping();
	m->set_id(mapping_id);
	m->set_memory_start(mapping.memory_start);
	m->set_memory_limit(mapping.memory_limit);
	m->set_file_offset(mapping.file_offset);
	m->set_filename(mapping.filename);
	m->set_build_id(mapping.build_id);
	m->set_has_functions(mapping.debug_info.has_functions);
	m->set_has_filenames(mapping.debug_info.has_filenames);
	m->set_has_line_numbers(mapping.debug_info.has_line_numbers);
	m->set_has_inline_frames(mapping.debug_info.has_inline_frames);
	}

	void GProfileBuilder::WriteMappings() {
	// The convention in pprof files is to write the mapping for the main
	// binary first. So lets do just that.
	std::optional<uint64_t> main_mapping_id = GuessMainBinary();
	if (main_mapping_id) {
	WriteMapping(*main_mapping_id);
	}

	for (size_t i = 0; i < mappings_.size(); ++i) {
	uint64_t mapping_id = i + 1;
	if (main_mapping_id && *main_mapping_id == mapping_id) {
	continue;
	}
	WriteMapping(mapping_id);
	}
	}

	std::optional<uint64_t> GProfileBuilder::GuessMainBinary() const {
	std::vector<int64_t> mapping_scores;

	for (const auto& mapping : mappings_) {
	mapping_scores.push_back(mapping.ComputeMainBinaryScore());
	}

	auto it = std::max_element(mapping_scores.begin(), mapping_scores.end());

	if (it == mapping_scores.end()) {
	return std::nullopt;
	}

	return static_cast<uint64_t>(std::distance(mapping_scores.begin(), it) + 1);
	}

	} // namespace trace_processor
	} // namespace perfetto