clang/lib/Tooling/JSONCompilationDatabase.cpp - external/github.com/llvm/llvm-project.git - Git at Google

 //===--- JSONCompilationDatabase.cpp - ------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file contains the implementation of the JSONCompilationDatabase.
 //
 //===----------------------------------------------------------------------===//

 #include "clang/Tooling/JSONCompilationDatabase.h"
 #include "clang/Tooling/CompilationDatabase.h"
 #include "clang/Tooling/CompilationDatabasePluginRegistry.h"
 #include "clang/Tooling/Tooling.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/StringSaver.h"
 #include <system_error>

 namespace clang {
 namespace tooling {

 namespace {

 /// \brief A parser for escaped strings of command line arguments.
 ///
 /// Assumes \-escaping for quoted arguments (see the documentation of
 /// unescapeCommandLine(...)).
 class CommandLineArgumentParser {
  public:
   CommandLineArgumentParser(StringRef CommandLine)
       : Input(CommandLine), Position(Input.begin()-1) {}

   std::vector<std::string> parse() {
     bool HasMoreInput = true;
     while (HasMoreInput && nextNonWhitespace()) {
       std::string Argument;
       HasMoreInput = parseStringInto(Argument);
       CommandLine.push_back(Argument);
     }
     return CommandLine;
   }

  private:
   // All private methods return true if there is more input available.

   bool parseStringInto(std::string &String) {
     do {
       if (*Position == '"') {
         if (!parseDoubleQuotedStringInto(String)) return false;
       } else if (*Position == '\'') {
         if (!parseSingleQuotedStringInto(String)) return false;
       } else {
         if (!parseFreeStringInto(String)) return false;
       }
     } while (*Position != ' ');
     return true;
   }

   bool parseDoubleQuotedStringInto(std::string &String) {
     if (!next()) return false;
     while (*Position != '"') {
       if (!skipEscapeCharacter()) return false;
       String.push_back(*Position);
       if (!next()) return false;
     }
     return next();
   }

   bool parseSingleQuotedStringInto(std::string &String) {
     if (!next()) return false;
     while (*Position != '\'') {
       String.push_back(*Position);
       if (!next()) return false;
     }
     return next();
   }

   bool parseFreeStringInto(std::string &String) {
     do {
       if (!skipEscapeCharacter()) return false;
       String.push_back(*Position);
       if (!next()) return false;
     } while (*Position != ' ' && *Position != '"' && *Position != '\'');
     return true;
   }

   bool skipEscapeCharacter() {
     if (*Position == '\\') {
       return next();
     }
     return true;
   }

   bool nextNonWhitespace() {
     do {
       if (!next()) return false;
     } while (*Position == ' ');
     return true;
   }

   bool next() {
     ++Position;
     return Position != Input.end();
   }

   const StringRef Input;
   StringRef::iterator Position;
   std::vector<std::string> CommandLine;
 };

 std::vector<std::string> unescapeCommandLine(JSONCommandLineSyntax Syntax,
                                              StringRef EscapedCommandLine) {
   if (Syntax == JSONCommandLineSyntax::AutoDetect) {
     Syntax = JSONCommandLineSyntax::Gnu;
     llvm::Triple Triple(llvm::sys::getProcessTriple());
     if (Triple.getOS() == llvm::Triple::OSType::Win32) {
       // Assume Windows command line parsing on Win32 unless the triple
       // explicitly tells us otherwise.
       if (!Triple.hasEnvironment() ||
           Triple.getEnvironment() == llvm::Triple::EnvironmentType::MSVC)
         Syntax = JSONCommandLineSyntax::Windows;
     }
   }

   if (Syntax == JSONCommandLineSyntax::Windows) {
     llvm::BumpPtrAllocator Alloc;
     llvm::StringSaver Saver(Alloc);
     llvm::SmallVector<const char *, 64> T;
     llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T);
     std::vector<std::string> Result(T.begin(), T.end());
     return Result;
   }
   assert(Syntax == JSONCommandLineSyntax::Gnu);
   CommandLineArgumentParser parser(EscapedCommandLine);
   return parser.parse();
 }

 class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin {
   std::unique_ptr<CompilationDatabase>
   loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override {
     SmallString<1024> JSONDatabasePath(Directory);
     llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");
     return JSONCompilationDatabase::loadFromFile(
         JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);
   }
 };

 } // end namespace

 // Register the JSONCompilationDatabasePlugin with the
 // CompilationDatabasePluginRegistry using this statically initialized variable.
 static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin>
 X("json-compilation-database", "Reads JSON formatted compilation databases");

 // This anchor is used to force the linker to link in the generated object file
 // and thus register the JSONCompilationDatabasePlugin.
 volatile int JSONAnchorSource = 0;

 std::unique_ptr<JSONCompilationDatabase>
 JSONCompilationDatabase::loadFromFile(StringRef FilePath,
                                       std::string &ErrorMessage,
                                       JSONCommandLineSyntax Syntax) {
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer =
       llvm::MemoryBuffer::getFile(FilePath);
   if (std::error_code Result = DatabaseBuffer.getError()) {
     ErrorMessage = "Error while opening JSON database: " + Result.message();
     return nullptr;
   }
   std::unique_ptr<JSONCompilationDatabase> Database(
       new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax));
   if (!Database->parse(ErrorMessage))
     return nullptr;
   return Database;
 }

 std::unique_ptr<JSONCompilationDatabase>
 JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,
                                         std::string &ErrorMessage,
                                         JSONCommandLineSyntax Syntax) {
   std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer(
       llvm::MemoryBuffer::getMemBuffer(DatabaseString));
   std::unique_ptr<JSONCompilationDatabase> Database(
       new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax));
   if (!Database->parse(ErrorMessage))
     return nullptr;
   return Database;
 }

 std::vector<CompileCommand>
 JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {
   SmallString<128> NativeFilePath;
   llvm::sys::path::native(FilePath, NativeFilePath);

   std::string Error;
   llvm::raw_string_ostream ES(Error);
   StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES);
   if (Match.empty())
     return std::vector<CompileCommand>();
   llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
     CommandsRefI = IndexByFile.find(Match);
   if (CommandsRefI == IndexByFile.end())
     return std::vector<CompileCommand>();
   std::vector<CompileCommand> Commands;
   getCommands(CommandsRefI->getValue(), Commands);
   return Commands;
 }

 std::vector<std::string>
 JSONCompilationDatabase::getAllFiles() const {
   std::vector<std::string> Result;

   llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
     CommandsRefI = IndexByFile.begin();
   const llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
     CommandsRefEnd = IndexByFile.end();
   for (; CommandsRefI != CommandsRefEnd; ++CommandsRefI) {
     Result.push_back(CommandsRefI->first().str());
   }

   return Result;
 }

 std::vector<CompileCommand>
 JSONCompilationDatabase::getAllCompileCommands() const {
   std::vector<CompileCommand> Commands;
   getCommands(AllCommands, Commands);
   return Commands;
 }

 static std::vector<std::string>
 nodeToCommandLine(JSONCommandLineSyntax Syntax,
                   const std::vector<llvm::yaml::ScalarNode *> &Nodes) {
   SmallString<1024> Storage;
   if (Nodes.size() == 1) {
     return unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage));
   }
   std::vector<std::string> Arguments;
   for (auto *Node : Nodes) {
     Arguments.push_back(Node->getValue(Storage));
   }
   return Arguments;
 }

 void JSONCompilationDatabase::getCommands(
     ArrayRef<CompileCommandRef> CommandsRef,
     std::vector<CompileCommand> &Commands) const {
   for (int I = 0, E = CommandsRef.size(); I != E; ++I) {
     SmallString<8> DirectoryStorage;
     SmallString<32> FilenameStorage;
     SmallString<32> OutputStorage;
     auto Output = std::get<3>(CommandsRef[I]);
     Commands.emplace_back(
         std::get<0>(CommandsRef[I])->getValue(DirectoryStorage),
         std::get<1>(CommandsRef[I])->getValue(FilenameStorage),
         nodeToCommandLine(Syntax, std::get<2>(CommandsRef[I])),
         Output ? Output->getValue(OutputStorage) : "");
   }
 }

 bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {
   llvm::yaml::document_iterator I = YAMLStream.begin();
   if (I == YAMLStream.end()) {
     ErrorMessage = "Error while parsing YAML.";
     return false;
   }
   llvm::yaml::Node *Root = I->getRoot();
   if (!Root) {
     ErrorMessage = "Error while parsing YAML.";
     return false;
   }
   llvm::yaml::SequenceNode *Array = dyn_cast<llvm::yaml::SequenceNode>(Root);
   if (!Array) {
     ErrorMessage = "Expected array.";
     return false;
   }
   for (auto& NextObject : *Array) {
     llvm::yaml::MappingNode *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject);
     if (!Object) {
       ErrorMessage = "Expected object.";
       return false;
     }
     llvm::yaml::ScalarNode *Directory = nullptr;
     llvm::Optional<std::vector<llvm::yaml::ScalarNode *>> Command;
     llvm::yaml::ScalarNode *File = nullptr;
     llvm::yaml::ScalarNode *Output = nullptr;
     for (auto& NextKeyValue : *Object) {
       llvm::yaml::ScalarNode *KeyString =
           dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
       if (!KeyString) {
         ErrorMessage = "Expected strings as key.";
         return false;
       }
       SmallString<10> KeyStorage;
       StringRef KeyValue = KeyString->getValue(KeyStorage);
       llvm::yaml::Node *Value = NextKeyValue.getValue();
       if (!Value) {
         ErrorMessage = "Expected value.";
         return false;
       }
       llvm::yaml::ScalarNode *ValueString =
           dyn_cast<llvm::yaml::ScalarNode>(Value);
       llvm::yaml::SequenceNode *SequenceString =
           dyn_cast<llvm::yaml::SequenceNode>(Value);
       if (KeyValue == "arguments" && !SequenceString) {
         ErrorMessage = "Expected sequence as value.";
         return false;
       } else if (KeyValue != "arguments" && !ValueString) {
         ErrorMessage = "Expected string as value.";
         return false;
       }
       if (KeyValue == "directory") {
         Directory = ValueString;
       } else if (KeyValue == "arguments") {
         Command = std::vector<llvm::yaml::ScalarNode *>();
         for (auto &Argument : *SequenceString) {
           auto Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument);
           if (!Scalar) {
             ErrorMessage = "Only strings are allowed in 'arguments'.";
             return false;
           }
           Command->push_back(Scalar);
         }
       } else if (KeyValue == "command") {
         if (!Command)
           Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString);
       } else if (KeyValue == "file") {
         File = ValueString;
       } else if (KeyValue == "output") {
         Output = ValueString;
       } else {
         ErrorMessage = ("Unknown key: \"" +
                         KeyString->getRawValue() + "\"").str();
         return false;
       }
     }
     if (!File) {
       ErrorMessage = "Missing key: \"file\".";
       return false;
     }
     if (!Command) {
       ErrorMessage = "Missing key: \"command\" or \"arguments\".";
       return false;
     }
     if (!Directory) {
       ErrorMessage = "Missing key: \"directory\".";
       return false;
     }
     SmallString<8> FileStorage;
     StringRef FileName = File->getValue(FileStorage);
     SmallString<128> NativeFilePath;
     if (llvm::sys::path::is_relative(FileName)) {
       SmallString<8> DirectoryStorage;
       SmallString<128> AbsolutePath(
           Directory->getValue(DirectoryStorage));
       llvm::sys::path::append(AbsolutePath, FileName);
       llvm::sys::path::native(AbsolutePath, NativeFilePath);
     } else {
       llvm::sys::path::native(FileName, NativeFilePath);
     }
     auto Cmd = CompileCommandRef(Directory, File, *Command, Output);
     IndexByFile[NativeFilePath].push_back(Cmd);
     AllCommands.push_back(Cmd);
     MatchTrie.insert(NativeFilePath);
   }
   return true;
 }

 } // end namespace tooling
 } // end namespace clang
	//===--- JSONCompilationDatabase.cpp - ------------------------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file contains the implementation of the JSONCompilationDatabase.
	//
	//===----------------------------------------------------------------------===//

	#include "clang/Tooling/JSONCompilationDatabase.h"
	#include "clang/Tooling/CompilationDatabase.h"
	#include "clang/Tooling/CompilationDatabasePluginRegistry.h"
	#include "clang/Tooling/Tooling.h"
	#include "llvm/ADT/SmallString.h"
	#include "llvm/Support/Allocator.h"
	#include "llvm/Support/CommandLine.h"
	#include "llvm/Support/Path.h"
	#include "llvm/Support/StringSaver.h"
	#include <system_error>

	namespace clang {
	namespace tooling {

	namespace {

	/// \brief A parser for escaped strings of command line arguments.
	///
	/// Assumes \-escaping for quoted arguments (see the documentation of
	/// unescapeCommandLine(...)).
	class CommandLineArgumentParser {
	public:
	CommandLineArgumentParser(StringRef CommandLine)
	: Input(CommandLine), Position(Input.begin()-1) {}

	std::vector<std::string> parse() {
	bool HasMoreInput = true;
	while (HasMoreInput && nextNonWhitespace()) {
	std::string Argument;
	HasMoreInput = parseStringInto(Argument);
	CommandLine.push_back(Argument);
	}
	return CommandLine;
	}

	private:
	// All private methods return true if there is more input available.

	bool parseStringInto(std::string &String) {
	do {
	if (*Position == '"') {
	if (!parseDoubleQuotedStringInto(String)) return false;
	} else if (*Position == '\'') {
	if (!parseSingleQuotedStringInto(String)) return false;
	} else {
	if (!parseFreeStringInto(String)) return false;
	}
	} while (*Position != ' ');
	return true;
	}

	bool parseDoubleQuotedStringInto(std::string &String) {
	if (!next()) return false;
	while (*Position != '"') {
	if (!skipEscapeCharacter()) return false;
	String.push_back(*Position);
	if (!next()) return false;
	}
	return next();
	}

	bool parseSingleQuotedStringInto(std::string &String) {
	if (!next()) return false;
	while (*Position != '\'') {
	String.push_back(*Position);
	if (!next()) return false;
	}
	return next();
	}

	bool parseFreeStringInto(std::string &String) {
	do {
	if (!skipEscapeCharacter()) return false;
	String.push_back(*Position);
	if (!next()) return false;
	} while (Position != ' ' && Position != '"' && *Position != '\'');
	return true;
	}

	bool skipEscapeCharacter() {
	if (*Position == '\\') {
	return next();
	}
	return true;
	}

	bool nextNonWhitespace() {
	do {
	if (!next()) return false;
	} while (*Position == ' ');
	return true;
	}

	bool next() {
	++Position;
	return Position != Input.end();
	}

	const StringRef Input;
	StringRef::iterator Position;
	std::vector<std::string> CommandLine;
	};

	std::vector<std::string> unescapeCommandLine(JSONCommandLineSyntax Syntax,
	StringRef EscapedCommandLine) {
	if (Syntax == JSONCommandLineSyntax::AutoDetect) {
	Syntax = JSONCommandLineSyntax::Gnu;
	llvm::Triple Triple(llvm::sys::getProcessTriple());
	if (Triple.getOS() == llvm::Triple::OSType::Win32) {
	// Assume Windows command line parsing on Win32 unless the triple
	// explicitly tells us otherwise.
	if (!Triple.hasEnvironment() \|\|
	Triple.getEnvironment() == llvm::Triple::EnvironmentType::MSVC)
	Syntax = JSONCommandLineSyntax::Windows;
	}
	}

	if (Syntax == JSONCommandLineSyntax::Windows) {
	llvm::BumpPtrAllocator Alloc;
	llvm::StringSaver Saver(Alloc);
	llvm::SmallVector<const char *, 64> T;
	llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T);
	std::vector<std::string> Result(T.begin(), T.end());
	return Result;
	}
	assert(Syntax == JSONCommandLineSyntax::Gnu);
	CommandLineArgumentParser parser(EscapedCommandLine);
	return parser.parse();
	}

	class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin {
	std::unique_ptr<CompilationDatabase>
	loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override {
	SmallString<1024> JSONDatabasePath(Directory);
	llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");
	return JSONCompilationDatabase::loadFromFile(
	JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);
	}
	};

	} // end namespace

	// Register the JSONCompilationDatabasePlugin with the
	// CompilationDatabasePluginRegistry using this statically initialized variable.
	static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin>
	X("json-compilation-database", "Reads JSON formatted compilation databases");

	// This anchor is used to force the linker to link in the generated object file
	// and thus register the JSONCompilationDatabasePlugin.
	volatile int JSONAnchorSource = 0;

	std::unique_ptr<JSONCompilationDatabase>
	JSONCompilationDatabase::loadFromFile(StringRef FilePath,
	std::string &ErrorMessage,
	JSONCommandLineSyntax Syntax) {
	llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer =
	llvm::MemoryBuffer::getFile(FilePath);
	if (std::error_code Result = DatabaseBuffer.getError()) {
	ErrorMessage = "Error while opening JSON database: " + Result.message();
	return nullptr;
	}
	std::unique_ptr<JSONCompilationDatabase> Database(
	new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax));
	if (!Database->parse(ErrorMessage))
	return nullptr;
	return Database;
	}

	std::unique_ptr<JSONCompilationDatabase>
	JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,
	std::string &ErrorMessage,
	JSONCommandLineSyntax Syntax) {
	std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer(
	llvm::MemoryBuffer::getMemBuffer(DatabaseString));
	std::unique_ptr<JSONCompilationDatabase> Database(
	new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax));
	if (!Database->parse(ErrorMessage))
	return nullptr;
	return Database;
	}

	std::vector<CompileCommand>
	JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {
	SmallString<128> NativeFilePath;
	llvm::sys::path::native(FilePath, NativeFilePath);

	std::string Error;
	llvm::raw_string_ostream ES(Error);
	StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES);
	if (Match.empty())
	return std::vector<CompileCommand>();
	llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
	CommandsRefI = IndexByFile.find(Match);
	if (CommandsRefI == IndexByFile.end())
	return std::vector<CompileCommand>();
	std::vector<CompileCommand> Commands;
	getCommands(CommandsRefI->getValue(), Commands);
	return Commands;
	}

	std::vector<std::string>
	JSONCompilationDatabase::getAllFiles() const {
	std::vector<std::string> Result;

	llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
	CommandsRefI = IndexByFile.begin();
	const llvm::StringMap< std::vector<CompileCommandRef> >::const_iterator
	CommandsRefEnd = IndexByFile.end();
	for (; CommandsRefI != CommandsRefEnd; ++CommandsRefI) {
	Result.push_back(CommandsRefI->first().str());
	}

	return Result;
	}

	std::vector<CompileCommand>
	JSONCompilationDatabase::getAllCompileCommands() const {
	std::vector<CompileCommand> Commands;
	getCommands(AllCommands, Commands);
	return Commands;
	}

	static std::vector<std::string>
	nodeToCommandLine(JSONCommandLineSyntax Syntax,
	const std::vector<llvm::yaml::ScalarNode *> &Nodes) {
	SmallString<1024> Storage;
	if (Nodes.size() == 1) {
	return unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage));
	}
	std::vector<std::string> Arguments;
	for (auto *Node : Nodes) {
	Arguments.push_back(Node->getValue(Storage));
	}
	return Arguments;
	}

	void JSONCompilationDatabase::getCommands(
	ArrayRef<CompileCommandRef> CommandsRef,
	std::vector<CompileCommand> &Commands) const {
	for (int I = 0, E = CommandsRef.size(); I != E; ++I) {
	SmallString<8> DirectoryStorage;
	SmallString<32> FilenameStorage;
	SmallString<32> OutputStorage;
	auto Output = std::get<3>(CommandsRef[I]);
	Commands.emplace_back(
	std::get<0>(CommandsRef[I])->getValue(DirectoryStorage),
	std::get<1>(CommandsRef[I])->getValue(FilenameStorage),
	nodeToCommandLine(Syntax, std::get<2>(CommandsRef[I])),
	Output ? Output->getValue(OutputStorage) : "");
	}
	}

	bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {
	llvm::yaml::document_iterator I = YAMLStream.begin();
	if (I == YAMLStream.end()) {
	ErrorMessage = "Error while parsing YAML.";
	return false;
	}
	llvm::yaml::Node *Root = I->getRoot();
	if (!Root) {
	ErrorMessage = "Error while parsing YAML.";
	return false;
	}
	llvm::yaml::SequenceNode *Array = dyn_cast<llvm::yaml::SequenceNode>(Root);
	if (!Array) {
	ErrorMessage = "Expected array.";
	return false;
	}
	for (auto& NextObject : *Array) {
	llvm::yaml::MappingNode *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject);
	if (!Object) {
	ErrorMessage = "Expected object.";
	return false;
	}
	llvm::yaml::ScalarNode *Directory = nullptr;
	llvm::Optional<std::vector<llvm::yaml::ScalarNode *>> Command;
	llvm::yaml::ScalarNode *File = nullptr;
	llvm::yaml::ScalarNode *Output = nullptr;
	for (auto& NextKeyValue : *Object) {
	llvm::yaml::ScalarNode *KeyString =
	dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
	if (!KeyString) {
	ErrorMessage = "Expected strings as key.";
	return false;
	}
	SmallString<10> KeyStorage;
	StringRef KeyValue = KeyString->getValue(KeyStorage);
	llvm::yaml::Node *Value = NextKeyValue.getValue();
	if (!Value) {
	ErrorMessage = "Expected value.";
	return false;
	}
	llvm::yaml::ScalarNode *ValueString =
	dyn_cast<llvm::yaml::ScalarNode>(Value);
	llvm::yaml::SequenceNode *SequenceString =
	dyn_cast<llvm::yaml::SequenceNode>(Value);
	if (KeyValue == "arguments" && !SequenceString) {
	ErrorMessage = "Expected sequence as value.";
	return false;
	} else if (KeyValue != "arguments" && !ValueString) {
	ErrorMessage = "Expected string as value.";
	return false;
	}
	if (KeyValue == "directory") {
	Directory = ValueString;
	} else if (KeyValue == "arguments") {
	Command = std::vector<llvm::yaml::ScalarNode *>();
	for (auto &Argument : *SequenceString) {
	auto Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument);
	if (!Scalar) {
	ErrorMessage = "Only strings are allowed in 'arguments'.";
	return false;
	}
	Command->push_back(Scalar);
	}
	} else if (KeyValue == "command") {
	if (!Command)
	Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString);
	} else if (KeyValue == "file") {
	File = ValueString;
	} else if (KeyValue == "output") {
	Output = ValueString;
	} else {
	ErrorMessage = ("Unknown key: \"" +
	KeyString->getRawValue() + "\"").str();
	return false;
	}
	}
	if (!File) {
	ErrorMessage = "Missing key: \"file\".";
	return false;
	}
	if (!Command) {
	ErrorMessage = "Missing key: \"command\" or \"arguments\".";
	return false;
	}
	if (!Directory) {
	ErrorMessage = "Missing key: \"directory\".";
	return false;
	}
	SmallString<8> FileStorage;
	StringRef FileName = File->getValue(FileStorage);
	SmallString<128> NativeFilePath;
	if (llvm::sys::path::is_relative(FileName)) {
	SmallString<8> DirectoryStorage;
	SmallString<128> AbsolutePath(
	Directory->getValue(DirectoryStorage));
	llvm::sys::path::append(AbsolutePath, FileName);
	llvm::sys::path::native(AbsolutePath, NativeFilePath);
	} else {
	llvm::sys::path::native(FileName, NativeFilePath);
	}
	auto Cmd = CompileCommandRef(Directory, File, *Command, Output);
	IndexByFile[NativeFilePath].push_back(Cmd);
	AllCommands.push_back(Cmd);
	MatchTrie.insert(NativeFilePath);
	}
	return true;
	}

	} // end namespace tooling
	} // end namespace clang