//===- JSONCompilationDatabase.cpp ----------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains the implementation of the JSONCompilationDatabase.
//
//===----------------------------------------------------------------------===//
#include "clang/Tooling/JSONCompilationDatabase.h"
#include "clang/Basic/LLVM.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "clang/Tooling/CompilationDatabasePluginRegistry.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/StringSaver.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/Support/YAMLParser.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <memory>
#include <string>
#include <system_error>
#include <tuple>
#include <utility>
#include <vector>
using namespace clang;
using namespace tooling;
namespace {
/// 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();
}
// This plugin locates a nearby compile_command.json file, and also infers
// compile commands for files not present in the database.
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");
auto Base = JSONCompilationDatabase::loadFromFile(
JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);
return Base ? inferTargetAndDriverMode(
inferMissingCompileCommands(expandResponseFiles(
std::move(Base), llvm::vfs::getRealFileSystem())))
: nullptr;
}
};
} // 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");
namespace clang {
namespace tooling {
// This anchor is used to force the linker to link in the generated object file
// and thus register the JSONCompilationDatabasePlugin.
volatile int JSONAnchorSource = 0;
} // namespace tooling
} // namespace clang
std::unique_ptr<JSONCompilationDatabase>
JSONCompilationDatabase::loadFromFile(StringRef FilePath,
std::string &ErrorMessage,
JSONCommandLineSyntax Syntax) {
// Don't mmap: if we're a long-lived process, the build system may overwrite.
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer =
llvm::MemoryBuffer::getFile(FilePath, /*IsText=*/false,
/*RequiresNullTerminator=*/true,
/*IsVolatile=*/true);
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::getMemBufferCopy(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 {};
const auto CommandsRefI = IndexByFile.find(Match);
if (CommandsRefI == IndexByFile.end())
return {};
std::vector<CompileCommand> Commands;
getCommands(CommandsRefI->getValue(), Commands);
return Commands;
}
std::vector<std::string>
JSONCompilationDatabase::getAllFiles() const {
std::vector<std::string> Result;
for (const auto &CommandRef : IndexByFile)
Result.push_back(CommandRef.first().str());
return Result;
}
std::vector<CompileCommand>
JSONCompilationDatabase::getAllCompileCommands() const {
std::vector<CompileCommand> Commands;
getCommands(AllCommands, Commands);
return Commands;
}
static llvm::StringRef stripExecutableExtension(llvm::StringRef Name) {
Name.consume_back(".exe");
return Name;
}
// There are compiler-wrappers (ccache, distcc, gomacc) that take the "real"
// compiler as an argument, e.g. distcc gcc -O3 foo.c.
// These end up in compile_commands.json when people set CC="distcc gcc".
// Clang's driver doesn't understand this, so we need to unwrap.
static bool unwrapCommand(std::vector<std::string> &Args) {
if (Args.size() < 2)
return false;
StringRef Wrapper =
stripExecutableExtension(llvm::sys::path::filename(Args.front()));
if (Wrapper == "distcc" || Wrapper == "gomacc" || Wrapper == "ccache" ||
Wrapper == "sccache") {
// Most of these wrappers support being invoked 3 ways:
// `distcc g++ file.c` This is the mode we're trying to match.
// We need to drop `distcc`.
// `distcc file.c` This acts like compiler is cc or similar.
// Clang's driver can handle this, no change needed.
// `g++ file.c` g++ is a symlink to distcc.
// We don't even notice this case, and all is well.
//
// We need to distinguish between the first and second case.
// The wrappers themselves don't take flags, so Args[1] is a compiler flag,
// an input file, or a compiler. Inputs have extensions, compilers don't.
bool HasCompiler =
(Args[1][0] != '-') &&
!llvm::sys::path::has_extension(stripExecutableExtension(Args[1]));
if (HasCompiler) {
Args.erase(Args.begin());
return true;
}
// If !HasCompiler, wrappers act like GCC. Fine: so do we.
}
return false;
}
static std::vector<std::string>
nodeToCommandLine(JSONCommandLineSyntax Syntax,
const std::vector<llvm::yaml::ScalarNode *> &Nodes) {
SmallString<1024> Storage;
std::vector<std::string> Arguments;
if (Nodes.size() == 1)
Arguments = unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage));
else
for (const auto *Node : Nodes)
Arguments.push_back(std::string(Node->getValue(Storage)));
// There may be multiple wrappers: using distcc and ccache together is common.
while (unwrapCommand(Arguments))
;
return Arguments;
}
void JSONCompilationDatabase::getCommands(
ArrayRef<CompileCommandRef> CommandsRef,
std::vector<CompileCommand> &Commands) const {
for (const auto &CommandRef : CommandsRef) {
SmallString<8> DirectoryStorage;
SmallString<32> FilenameStorage;
SmallString<32> OutputStorage;
auto Output = std::get<3>(CommandRef);
Commands.emplace_back(
std::get<0>(CommandRef)->getValue(DirectoryStorage),
std::get<1>(CommandRef)->getValue(FilenameStorage),
nodeToCommandLine(Syntax, std::get<2>(CommandRef)),
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;
}
auto *Array = dyn_cast<llvm::yaml::SequenceNode>(Root);
if (!Array) {
ErrorMessage = "Expected array.";
return false;
}
for (auto &NextObject : *Array) {
auto *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) {
auto *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;
}
auto *ValueString = dyn_cast<llvm::yaml::ScalarNode>(Value);
auto *SequenceString = dyn_cast<llvm::yaml::SequenceNode>(Value);
if (KeyValue == "arguments") {
if (!SequenceString) {
ErrorMessage = "Expected sequence as value.";
return false;
}
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 (!ValueString) {
ErrorMessage = "Expected string as value.";
return false;
}
if (KeyValue == "directory") {
Directory = ValueString;
} 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::remove_dots(AbsolutePath, /*remove_dot_dot=*/ true);
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;
}
