tools/ftrace_proto_gen/ftrace_proto_gen.cc - platform/external/perfetto - Gitiles

 /*
  * Copyright (C) 2018 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 "tools/ftrace_proto_gen/ftrace_proto_gen.h"

 #include <algorithm>
 #include <fstream>
 #include <regex>

 #include "perfetto/base/logging.h"
 #include "perfetto/base/string_splitter.h"

 namespace perfetto {

 namespace {

 bool StartsWith(const std::string& str, const std::string& prefix) {
   return str.compare(0, prefix.length(), prefix) == 0;
 }

 bool Contains(const std::string& haystack, const std::string& needle) {
   return haystack.find(needle) != std::string::npos;
 }

 }  // namespace

 FtraceEventName::FtraceEventName(const std::string& full_name) {
   if (full_name == "removed") {
     valid_ = false;
     return;
   }
   name_ = full_name.substr(full_name.find('/') + 1, std::string::npos);
   group_ = full_name.substr(0, full_name.find('/'));
   valid_ = true;
 }

 bool FtraceEventName::valid() const {
   return valid_;
 }

 const std::string& FtraceEventName::name() const {
   PERFETTO_CHECK(valid_);
   return name_;
 }

 const std::string& FtraceEventName::group() const {
   PERFETTO_CHECK(valid_);
   return group_;
 }

 std::string ToCamelCase(const std::string& s) {
   std::string result;
   result.reserve(s.size());
   bool upperCaseNextChar = true;
   for (size_t i = 0; i < s.size(); i++) {
     char c = s[i];
     if (c == '_') {
       upperCaseNextChar = true;
       continue;
     }
     if (upperCaseNextChar) {
       upperCaseNextChar = false;
       c = static_cast<char>(toupper(c));
     }
     result.push_back(c);
   }
   return result;
 }

 ProtoType ProtoType::GetSigned() const {
   PERFETTO_CHECK(type == NUMERIC);
   if (is_signed)
     return *this;

   if (size == 64) {
     return Numeric(64, true);
   }

   return Numeric(2 * size, true);
 }

 std::string ProtoType::ToString() const {
   switch (type) {
     case INVALID:
       PERFETTO_CHECK(false);
     case STRING:
       return "string";
     case NUMERIC: {
       std::string s;
       if (!is_signed)
         s += "u";
       s += "int";
       s += std::to_string(size);
       return s;
     }
   }
   PERFETTO_CHECK(false);  // for GCC.
 }

 // static
 ProtoType ProtoType::String() {
   return {STRING, 0, false};
 }

 // static
 ProtoType ProtoType::Invalid() {
   return {INVALID, 0, false};
 }

 // static
 ProtoType ProtoType::Numeric(uint16_t size, bool is_signed) {
   PERFETTO_CHECK(size == 32 || size == 64);
   return {NUMERIC, size, is_signed};
 }

 // static
 ProtoType ProtoType::FromDescriptor(
     google::protobuf::FieldDescriptor::Type type) {
   if (type == google::protobuf::FieldDescriptor::Type::TYPE_UINT64)
     return Numeric(64, false);

   if (type == google::protobuf::FieldDescriptor::Type::TYPE_INT64)
     return Numeric(64, true);

   if (type == google::protobuf::FieldDescriptor::Type::TYPE_UINT32)
     return Numeric(32, false);

   if (type == google::protobuf::FieldDescriptor::Type::TYPE_INT32)
     return Numeric(32, true);

   if (type == google::protobuf::FieldDescriptor::Type::TYPE_STRING)
     return String();

   return Invalid();
 }

 ProtoType GetCommon(ProtoType one, ProtoType other) {
   // Always need to prefer the LHS as it is the one already present
   // in the proto.
   if (one.type == ProtoType::STRING)
     return ProtoType::String();

   if (one.is_signed || other.is_signed) {
     one = one.GetSigned();
     other = other.GetSigned();
   }

   return ProtoType::Numeric(std::max(one.size, other.size), one.is_signed);
 }

 std::vector<FtraceEventName> ReadWhitelist(const std::string& filename) {
   std::string line;
   std::vector<FtraceEventName> lines;

   std::ifstream fin(filename, std::ios::in);
   if (!fin) {
     fprintf(stderr, "failed to open whitelist %s\n", filename.c_str());
     return lines;
   }
   while (std::getline(fin, line)) {
     if (!StartsWith(line, "#"))
       lines.emplace_back(FtraceEventName(line));
   }
   return lines;
 }

 ProtoType InferProtoType(const FtraceEvent::Field& field) {
   // Fixed length strings: "char foo[16]"
   if (std::regex_match(field.type_and_name, std::regex(R"(char \w+\[\d+\])")))
     return ProtoType::String();

   // String pointers: "__data_loc char[] foo" (as in
   // 'cpufreq_interactive_boost').
   if (Contains(field.type_and_name, "char[] "))
     return ProtoType::String();
   if (Contains(field.type_and_name, "char * "))
     return ProtoType::String();

   // Variable length strings: "char* foo"
   if (StartsWith(field.type_and_name, "char *"))
     return ProtoType::String();

   // Variable length strings: "char foo" + size: 0 (as in 'print').
   if (StartsWith(field.type_and_name, "char ") && field.size == 0)
     return ProtoType::String();

   // ino_t, i_ino and dev_t are 32bit on some devices 64bit on others. For the
   // protos we need to choose the largest possible size.
   if (StartsWith(field.type_and_name, "ino_t ") ||
       StartsWith(field.type_and_name, "i_ino ") ||
       StartsWith(field.type_and_name, "dev_t ")) {
     return ProtoType::Numeric(64, /* is_signed= */ false);
   }

   // Ints of various sizes:
   if (field.size <= 4)
     return ProtoType::Numeric(32, field.is_signed);
   if (field.size <= 8)
     return ProtoType::Numeric(64, field.is_signed);
   return ProtoType::Invalid();
 }

 void PrintEventFormatterMain(const std::set<std::string>& events) {
   printf(
       "\nAdd output to FormatEventText in "
       "tools/ftrace_proto_gen/ftrace_event_formatter.cc\n");
   for (auto event : events) {
     printf(
         "else if (event.has_%s()) {\nconst auto& inner = event.%s();\nline = "
         "Format%s(inner);\n} ",
         event.c_str(), event.c_str(), ToCamelCase(event).c_str());
   }
 }

 // Add output to ParseInode in ftrace_inode_handler
 void PrintInodeHandlerMain(const std::string& event_name,
                            const perfetto::Proto& proto) {
   for (const auto& p : proto.fields) {
     const Proto::Field& field = p.second;
     if (Contains(field.name, "ino") && !Contains(field.name, "minor"))
       printf(
           "else if (event.has_%s() && event.%s().%s()) {\n*inode = "
           "static_cast<uint64_t>(event.%s().%s());\n return true;\n} ",
           event_name.c_str(), event_name.c_str(), field.name.c_str(),
           event_name.c_str(), field.name.c_str());
   }
 }

 void PrintEventFormatterUsingStatements(const std::set<std::string>& events) {
   printf("\nAdd output to tools/ftrace_proto_gen/ftrace_event_formatter.cc\n");
   for (auto event : events) {
     printf("using protos::%sFtraceEvent;\n", ToCamelCase(event).c_str());
   }
 }

 void PrintEventFormatterFunctions(const std::set<std::string>& events) {
   printf(
       "\nAdd output to tools/ftrace_proto_gen/ftrace_event_formatter.cc and "
       "then manually go through format files to match fields\n");
   for (auto event : events) {
     printf(
         "std::string Format%s(const %sFtraceEvent& event) {"
         "\nchar line[2048];"
         "\nsprintf(line,\"%s: );\nreturn std::string(line);\n}\n",
         ToCamelCase(event).c_str(), ToCamelCase(event).c_str(), event.c_str());
   }
 }

 bool GenerateProto(const FtraceEvent& format, Proto* proto_out) {
   proto_out->name = ToCamelCase(format.name) + "FtraceEvent";
   proto_out->event_name = format.name;
   std::set<std::string> seen;
   // TODO(hjd): We should be cleverer about id assignment.
   uint32_t i = 1;
   for (const FtraceEvent::Field& field : format.fields) {
     std::string name = GetNameFromTypeAndName(field.type_and_name);
     // TODO(hjd): Handle dup names.
     if (name == "" || seen.count(name))
       continue;
     seen.insert(name);
     ProtoType type = InferProtoType(field);
     // Check we managed to infer a type.
     if (type.type == ProtoType::INVALID)
       continue;
     Proto::Field protofield{std::move(type), name, i};
     proto_out->AddField(std::move(protofield));
     i++;
   }

   return true;
 }

 void GenerateFtraceEventProto(
     const std::vector<FtraceEventName>& raw_whitelist) {
   std::string output_path = "protos/perfetto/trace/ftrace/ftrace_event.proto";
   std::ofstream fout(output_path.c_str(), std::ios::out);
   fout << "// Autogenerated by:\n";
   fout << std::string("// ") + __FILE__ + "\n";
   fout << "// Do not edit.\n\n";
   fout << R"(syntax = "proto2";)"
        << "\n";
   fout << "option optimize_for = LITE_RUNTIME;\n\n";
   for (const FtraceEventName& event : raw_whitelist) {
     if (!event.valid())
       continue;

     fout << R"(import "perfetto/trace/ftrace/)" << event.name() << R"(.proto";)"
          << "\n";
   }

   fout << "\n";
   fout << "package perfetto.protos;\n\n";
   fout << R"(message FtraceEvent {
   // Nanoseconds since an epoch.
   // Epoch is configurable by writing into trace_clock.
   // By default this timestamp is CPU local.
   // TODO: Figure out a story for reconciling the various clocks.
   optional uint64 timestamp = 1;

   optional uint32 pid = 2;

   oneof event {
 )";

   int i = 3;
   for (const FtraceEventName& event : raw_whitelist) {
     if (!event.valid()) {
       fout << "    // removed field with id " << i << ";\n";
       ++i;
       continue;
     }

     fout << "    " << ToCamelCase(event.name()) << "FtraceEvent "
          << event.name() << " = " << i << ";\n";
     ++i;
   }
   fout << "  }\n";
   fout << "}\n";
 }

 // Generates section of event_info.cc for a single event.
 std::string SingleEventInfo(perfetto::Proto proto,
                             const std::string& group,
                             const uint32_t proto_field_id) {
   std::string s = "";
   s += "    event->name = \"" + proto.event_name + "\";\n";
   s += "    event->group = \"" + group + "\";\n";
   s += "    event->proto_field_id = " + std::to_string(proto_field_id) + ";\n";

   for (const auto& field : proto.SortedFields()) {
     s += "    event->fields.push_back(MakeField(\"" + field->name + "\", " +
          std::to_string(field->number) + ", kProto" +
          ToCamelCase(field->type.ToString()) + "));\n";
   }
   return s;
 }

 // This will generate the event_info.cc file for the whitelisted protos.
 void GenerateEventInfo(const std::vector<std::string>& events_info) {
   std::string output_path = "src/ftrace_reader/event_info.cc";
   std::ofstream fout(output_path.c_str(), std::ios::out);
   if (!fout) {
     fprintf(stderr, "Failed to open %s\n", output_path.c_str());
     return;
   }

   std::string s = "// Autogenerated by:\n";
   s += std::string("// ") + __FILE__ + "\n";
   s += "// Do not edit.\n";
   s += R"(
 #include "src/ftrace_reader/event_info.h"

 namespace perfetto {

 std::vector<Event> GetStaticEventInfo() {
   std::vector<Event> events;
 )";

   for (const auto& event : events_info) {
     s += "\n";
     s += "  {\n";
     s += "    events.emplace_back(Event{});\n";
     s += "    Event* event = &events.back();\n";
     s += event;
     s += "  }\n";
   }

   s += R"(
   return events;
 }

 }  // namespace perfetto
 )";

   fout << s;
   fout.close();
 }

 Proto::Proto(std::string evt_name, const google::protobuf::Descriptor& desc)
     : name(desc.name()), event_name(evt_name) {
   for (int i = 0; i < desc.field_count(); ++i) {
     const google::protobuf::FieldDescriptor* field = desc.field(i);
     PERFETTO_CHECK(field);
     AddField(Field{ProtoType::FromDescriptor(field->type()), field->name(),
                    uint32_t(field->number())});
   }
 }

 std::vector<const Proto::Field*> Proto::SortedFields() {
   std::vector<const Proto::Field*> sorted_fields;

   for (const auto& p : fields) {
     sorted_fields.emplace_back(&p.second);
   }
   std::sort(sorted_fields.begin(), sorted_fields.end(),
             [](const Proto::Field* a, const Proto::Field* b) {
               return a->number < b->number;
             });
   return sorted_fields;
 }

 std::string Proto::ToString() {
   std::string s = "// Autogenerated by:\n";
   s += std::string("// ") + __FILE__ + "\n";
   s += "// Do not edit.\n";

   s += R"(
 syntax = "proto2";
 option optimize_for = LITE_RUNTIME;
 package perfetto.protos;

 )";

   s += "message " + name + " {\n";
   for (const auto field : SortedFields()) {
     s += "  optional " + field->type.ToString() + " " + field->name + " = " +
          std::to_string(field->number) + ";\n";
   }
   s += "}\n";
   return s;
 }

 void Proto::MergeFrom(const Proto& other) {
   // Always keep number from the left hand side.
   PERFETTO_CHECK(name == other.name);
   for (const auto& p : other.fields) {
     auto it = fields.find(p.first);
     if (it == fields.end()) {
       Proto::Field field = p.second;
       field.number = ++max_id;
       AddField(std::move(field));
     } else {
       it->second.type = GetCommon(it->second.type, p.second.type);
     }
   }
 }

 void Proto::AddField(Proto::Field other) {
   max_id = std::max(max_id, other.number);
   fields.emplace(other.name, std::move(other));
 }

 }  // namespace perfetto
	/*
	* Copyright (C) 2018 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 "tools/ftrace_proto_gen/ftrace_proto_gen.h"

	#include <algorithm>
	#include <fstream>
	#include <regex>

	#include "perfetto/base/logging.h"
	#include "perfetto/base/string_splitter.h"

	namespace perfetto {

	namespace {

	bool StartsWith(const std::string& str, const std::string& prefix) {
	return str.compare(0, prefix.length(), prefix) == 0;
	}

	bool Contains(const std::string& haystack, const std::string& needle) {
	return haystack.find(needle) != std::string::npos;
	}

	} // namespace

	FtraceEventName::FtraceEventName(const std::string& full_name) {
	if (full_name == "removed") {
	valid_ = false;
	return;
	}
	name_ = full_name.substr(full_name.find('/') + 1, std::string::npos);
	group_ = full_name.substr(0, full_name.find('/'));
	valid_ = true;
	}

	bool FtraceEventName::valid() const {
	return valid_;
	}

	const std::string& FtraceEventName::name() const {
	PERFETTO_CHECK(valid_);
	return name_;
	}

	const std::string& FtraceEventName::group() const {
	PERFETTO_CHECK(valid_);
	return group_;
	}

	std::string ToCamelCase(const std::string& s) {
	std::string result;
	result.reserve(s.size());
	bool upperCaseNextChar = true;
	for (size_t i = 0; i < s.size(); i++) {
	char c = s[i];
	if (c == '_') {
	upperCaseNextChar = true;
	continue;
	}
	if (upperCaseNextChar) {
	upperCaseNextChar = false;
	c = static_cast<char>(toupper(c));
	}
	result.push_back(c);
	}
	return result;
	}

	ProtoType ProtoType::GetSigned() const {
	PERFETTO_CHECK(type == NUMERIC);
	if (is_signed)
	return *this;

	if (size == 64) {
	return Numeric(64, true);
	}

	return Numeric(2 * size, true);
	}

	std::string ProtoType::ToString() const {
	switch (type) {
	case INVALID:
	PERFETTO_CHECK(false);
	case STRING:
	return "string";
	case NUMERIC: {
	std::string s;
	if (!is_signed)
	s += "u";
	s += "int";
	s += std::to_string(size);
	return s;
	}
	}
	PERFETTO_CHECK(false); // for GCC.
	}

	// static
	ProtoType ProtoType::String() {
	return {STRING, 0, false};
	}

	// static
	ProtoType ProtoType::Invalid() {
	return {INVALID, 0, false};
	}

	// static
	ProtoType ProtoType::Numeric(uint16_t size, bool is_signed) {
	PERFETTO_CHECK(size == 32 \|\| size == 64);
	return {NUMERIC, size, is_signed};
	}

	// static
	ProtoType ProtoType::FromDescriptor(
	google::protobuf::FieldDescriptor::Type type) {
	if (type == google::protobuf::FieldDescriptor::Type::TYPE_UINT64)
	return Numeric(64, false);

	if (type == google::protobuf::FieldDescriptor::Type::TYPE_INT64)
	return Numeric(64, true);

	if (type == google::protobuf::FieldDescriptor::Type::TYPE_UINT32)
	return Numeric(32, false);

	if (type == google::protobuf::FieldDescriptor::Type::TYPE_INT32)
	return Numeric(32, true);

	if (type == google::protobuf::FieldDescriptor::Type::TYPE_STRING)
	return String();

	return Invalid();
	}

	ProtoType GetCommon(ProtoType one, ProtoType other) {
	// Always need to prefer the LHS as it is the one already present
	// in the proto.
	if (one.type == ProtoType::STRING)
	return ProtoType::String();

	if (one.is_signed \|\| other.is_signed) {
	one = one.GetSigned();
	other = other.GetSigned();
	}

	return ProtoType::Numeric(std::max(one.size, other.size), one.is_signed);
	}

	std::vector<FtraceEventName> ReadWhitelist(const std::string& filename) {
	std::string line;
	std::vector<FtraceEventName> lines;

	std::ifstream fin(filename, std::ios::in);
	if (!fin) {
	fprintf(stderr, "failed to open whitelist %s\n", filename.c_str());
	return lines;
	}
	while (std::getline(fin, line)) {
	if (!StartsWith(line, "#"))
	lines.emplace_back(FtraceEventName(line));
	}
	return lines;
	}

	ProtoType InferProtoType(const FtraceEvent::Field& field) {
	// Fixed length strings: "char foo[16]"
	if (std::regex_match(field.type_and_name, std::regex(R"(char \w+\[\d+\])")))
	return ProtoType::String();

	// String pointers: "__data_loc char[] foo" (as in
	// 'cpufreq_interactive_boost').
	if (Contains(field.type_and_name, "char[] "))
	return ProtoType::String();
	if (Contains(field.type_and_name, "char * "))
	return ProtoType::String();

	// Variable length strings: "char* foo"
	if (StartsWith(field.type_and_name, "char *"))
	return ProtoType::String();

	// Variable length strings: "char foo" + size: 0 (as in 'print').
	if (StartsWith(field.type_and_name, "char ") && field.size == 0)
	return ProtoType::String();

	// ino_t, i_ino and dev_t are 32bit on some devices 64bit on others. For the
	// protos we need to choose the largest possible size.
	if (StartsWith(field.type_and_name, "ino_t ") \|\|
	StartsWith(field.type_and_name, "i_ino ") \|\|
	StartsWith(field.type_and_name, "dev_t ")) {
	return ProtoType::Numeric(64, /* is_signed= */ false);
	}

	// Ints of various sizes:
	if (field.size <= 4)
	return ProtoType::Numeric(32, field.is_signed);
	if (field.size <= 8)
	return ProtoType::Numeric(64, field.is_signed);
	return ProtoType::Invalid();
	}

	void PrintEventFormatterMain(const std::set<std::string>& events) {
	printf(
	"\nAdd output to FormatEventText in "
	"tools/ftrace_proto_gen/ftrace_event_formatter.cc\n");
	for (auto event : events) {
	printf(
	"else if (event.has_%s()) {\nconst auto& inner = event.%s();\nline = "
	"Format%s(inner);\n} ",
	event.c_str(), event.c_str(), ToCamelCase(event).c_str());
	}
	}

	// Add output to ParseInode in ftrace_inode_handler
	void PrintInodeHandlerMain(const std::string& event_name,
	const perfetto::Proto& proto) {
	for (const auto& p : proto.fields) {
	const Proto::Field& field = p.second;
	if (Contains(field.name, "ino") && !Contains(field.name, "minor"))
	printf(
	"else if (event.has_%s() && event.%s().%s()) {\n*inode = "
	"static_cast<uint64_t>(event.%s().%s());\n return true;\n} ",
	event_name.c_str(), event_name.c_str(), field.name.c_str(),
	event_name.c_str(), field.name.c_str());
	}
	}

	void PrintEventFormatterUsingStatements(const std::set<std::string>& events) {
	printf("\nAdd output to tools/ftrace_proto_gen/ftrace_event_formatter.cc\n");
	for (auto event : events) {
	printf("using protos::%sFtraceEvent;\n", ToCamelCase(event).c_str());
	}
	}

	void PrintEventFormatterFunctions(const std::set<std::string>& events) {
	printf(
	"\nAdd output to tools/ftrace_proto_gen/ftrace_event_formatter.cc and "
	"then manually go through format files to match fields\n");
	for (auto event : events) {
	printf(
	"std::string Format%s(const %sFtraceEvent& event) {"
	"\nchar line[2048];"
	"\nsprintf(line,\"%s: );\nreturn std::string(line);\n}\n",
	ToCamelCase(event).c_str(), ToCamelCase(event).c_str(), event.c_str());
	}
	}

	bool GenerateProto(const FtraceEvent& format, Proto* proto_out) {
	proto_out->name = ToCamelCase(format.name) + "FtraceEvent";
	proto_out->event_name = format.name;
	std::set<std::string> seen;
	// TODO(hjd): We should be cleverer about id assignment.
	uint32_t i = 1;
	for (const FtraceEvent::Field& field : format.fields) {
	std::string name = GetNameFromTypeAndName(field.type_and_name);
	// TODO(hjd): Handle dup names.
	if (name == "" \|\| seen.count(name))
	continue;
	seen.insert(name);
	ProtoType type = InferProtoType(field);
	// Check we managed to infer a type.
	if (type.type == ProtoType::INVALID)
	continue;
	Proto::Field protofield{std::move(type), name, i};
	proto_out->AddField(std::move(protofield));
	i++;
	}

	return true;
	}

	void GenerateFtraceEventProto(
	const std::vector<FtraceEventName>& raw_whitelist) {
	std::string output_path = "protos/perfetto/trace/ftrace/ftrace_event.proto";
	std::ofstream fout(output_path.c_str(), std::ios::out);
	fout << "// Autogenerated by:\n";
	fout << std::string("// ") + __FILE__ + "\n";
	fout << "// Do not edit.\n\n";
	fout << R"(syntax = "proto2";)"
	<< "\n";
	fout << "option optimize_for = LITE_RUNTIME;\n\n";
	for (const FtraceEventName& event : raw_whitelist) {
	if (!event.valid())
	continue;

	fout << R"(import "perfetto/trace/ftrace/)" << event.name() << R"(.proto";)"
	<< "\n";
	}

	fout << "\n";
	fout << "package perfetto.protos;\n\n";
	fout << R"(message FtraceEvent {
	// Nanoseconds since an epoch.
	// Epoch is configurable by writing into trace_clock.
	// By default this timestamp is CPU local.
	// TODO: Figure out a story for reconciling the various clocks.
	optional uint64 timestamp = 1;

	optional uint32 pid = 2;

	oneof event {
	)";

	int i = 3;
	for (const FtraceEventName& event : raw_whitelist) {
	if (!event.valid()) {
	fout << " // removed field with id " << i << ";\n";
	++i;
	continue;
	}

	fout << " " << ToCamelCase(event.name()) << "FtraceEvent "
	<< event.name() << " = " << i << ";\n";
	++i;
	}
	fout << " }\n";
	fout << "}\n";
	}

	// Generates section of event_info.cc for a single event.
	std::string SingleEventInfo(perfetto::Proto proto,
	const std::string& group,
	const uint32_t proto_field_id) {
	std::string s = "";
	s += " event->name = \"" + proto.event_name + "\";\n";
	s += " event->group = \"" + group + "\";\n";
	s += " event->proto_field_id = " + std::to_string(proto_field_id) + ";\n";

	for (const auto& field : proto.SortedFields()) {
	s += " event->fields.push_back(MakeField(\"" + field->name + "\", " +
	std::to_string(field->number) + ", kProto" +
	ToCamelCase(field->type.ToString()) + "));\n";
	}
	return s;
	}

	// This will generate the event_info.cc file for the whitelisted protos.
	void GenerateEventInfo(const std::vector<std::string>& events_info) {
	std::string output_path = "src/ftrace_reader/event_info.cc";
	std::ofstream fout(output_path.c_str(), std::ios::out);
	if (!fout) {
	fprintf(stderr, "Failed to open %s\n", output_path.c_str());
	return;
	}

	std::string s = "// Autogenerated by:\n";
	s += std::string("// ") + __FILE__ + "\n";
	s += "// Do not edit.\n";
	s += R"(
	#include "src/ftrace_reader/event_info.h"

	namespace perfetto {

	std::vector<Event> GetStaticEventInfo() {
	std::vector<Event> events;
	)";

	for (const auto& event : events_info) {
	s += "\n";
	s += " {\n";
	s += " events.emplace_back(Event{});\n";
	s += " Event* event = &events.back();\n";
	s += event;
	s += " }\n";
	}

	s += R"(
	return events;
	}

	} // namespace perfetto
	)";

	fout << s;
	fout.close();
	}

	Proto::Proto(std::string evt_name, const google::protobuf::Descriptor& desc)
	: name(desc.name()), event_name(evt_name) {
	for (int i = 0; i < desc.field_count(); ++i) {
	const google::protobuf::FieldDescriptor* field = desc.field(i);
	PERFETTO_CHECK(field);
	AddField(Field{ProtoType::FromDescriptor(field->type()), field->name(),
	uint32_t(field->number())});
	}
	}

	std::vector<const Proto::Field*> Proto::SortedFields() {
	std::vector<const Proto::Field*> sorted_fields;

	for (const auto& p : fields) {
	sorted_fields.emplace_back(&p.second);
	}
	std::sort(sorted_fields.begin(), sorted_fields.end(),
	[](const Proto::Field* a, const Proto::Field* b) {
	return a->number < b->number;
	});
	return sorted_fields;
	}

	std::string Proto::ToString() {
	std::string s = "// Autogenerated by:\n";
	s += std::string("// ") + __FILE__ + "\n";
	s += "// Do not edit.\n";

	s += R"(
	syntax = "proto2";
	option optimize_for = LITE_RUNTIME;
	package perfetto.protos;

	)";

	s += "message " + name + " {\n";
	for (const auto field : SortedFields()) {
	s += " optional " + field->type.ToString() + " " + field->name + " = " +
	std::to_string(field->number) + ";\n";
	}
	s += "}\n";
	return s;
	}

	void Proto::MergeFrom(const Proto& other) {
	// Always keep number from the left hand side.
	PERFETTO_CHECK(name == other.name);
	for (const auto& p : other.fields) {
	auto it = fields.find(p.first);
	if (it == fields.end()) {
	Proto::Field field = p.second;
	field.number = ++max_id;
	AddField(std::move(field));
	} else {
	it->second.type = GetCommon(it->second.type, p.second.type);
	}
	}
	}

	void Proto::AddField(Proto::Field other) {
	max_id = std::max(max_id, other.number);
	fields.emplace(other.name, std::move(other));
	}

	} // namespace perfetto