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      1 //===--- CompilationDatabase.cpp - ----------------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file contains implementations of the CompilationDatabase base class
     11 //  and the FixedCompilationDatabase.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "clang/Tooling/CompilationDatabase.h"
     16 #include "clang/Basic/Diagnostic.h"
     17 #include "clang/Basic/DiagnosticOptions.h"
     18 #include "clang/Driver/Action.h"
     19 #include "clang/Driver/Compilation.h"
     20 #include "clang/Driver/Driver.h"
     21 #include "clang/Driver/DriverDiagnostic.h"
     22 #include "clang/Driver/Job.h"
     23 #include "clang/Frontend/TextDiagnosticPrinter.h"
     24 #include "clang/Tooling/CompilationDatabasePluginRegistry.h"
     25 #include "clang/Tooling/Tooling.h"
     26 #include "llvm/ADT/SmallString.h"
     27 #include "llvm/Option/Arg.h"
     28 #include "llvm/Support/Host.h"
     29 #include "llvm/Support/Path.h"
     30 #include <sstream>
     31 #include <system_error>
     32 using namespace clang;
     33 using namespace tooling;
     34 
     35 CompilationDatabase::~CompilationDatabase() {}
     36 
     37 std::unique_ptr<CompilationDatabase>
     38 CompilationDatabase::loadFromDirectory(StringRef BuildDirectory,
     39                                        std::string &ErrorMessage) {
     40   std::stringstream ErrorStream;
     41   for (CompilationDatabasePluginRegistry::iterator
     42        It = CompilationDatabasePluginRegistry::begin(),
     43        Ie = CompilationDatabasePluginRegistry::end();
     44        It != Ie; ++It) {
     45     std::string DatabaseErrorMessage;
     46     std::unique_ptr<CompilationDatabasePlugin> Plugin(It->instantiate());
     47     if (std::unique_ptr<CompilationDatabase> DB =
     48             Plugin->loadFromDirectory(BuildDirectory, DatabaseErrorMessage))
     49       return DB;
     50     ErrorStream << It->getName() << ": " << DatabaseErrorMessage << "\n";
     51   }
     52   ErrorMessage = ErrorStream.str();
     53   return nullptr;
     54 }
     55 
     56 static std::unique_ptr<CompilationDatabase>
     57 findCompilationDatabaseFromDirectory(StringRef Directory,
     58                                      std::string &ErrorMessage) {
     59   std::stringstream ErrorStream;
     60   bool HasErrorMessage = false;
     61   while (!Directory.empty()) {
     62     std::string LoadErrorMessage;
     63 
     64     if (std::unique_ptr<CompilationDatabase> DB =
     65             CompilationDatabase::loadFromDirectory(Directory, LoadErrorMessage))
     66       return DB;
     67 
     68     if (!HasErrorMessage) {
     69       ErrorStream << "No compilation database found in " << Directory.str()
     70                   << " or any parent directory\n" << LoadErrorMessage;
     71       HasErrorMessage = true;
     72     }
     73 
     74     Directory = llvm::sys::path::parent_path(Directory);
     75   }
     76   ErrorMessage = ErrorStream.str();
     77   return nullptr;
     78 }
     79 
     80 std::unique_ptr<CompilationDatabase>
     81 CompilationDatabase::autoDetectFromSource(StringRef SourceFile,
     82                                           std::string &ErrorMessage) {
     83   SmallString<1024> AbsolutePath(getAbsolutePath(SourceFile));
     84   StringRef Directory = llvm::sys::path::parent_path(AbsolutePath);
     85 
     86   std::unique_ptr<CompilationDatabase> DB =
     87       findCompilationDatabaseFromDirectory(Directory, ErrorMessage);
     88 
     89   if (!DB)
     90     ErrorMessage = ("Could not auto-detect compilation database for file \"" +
     91                    SourceFile + "\"\n" + ErrorMessage).str();
     92   return DB;
     93 }
     94 
     95 std::unique_ptr<CompilationDatabase>
     96 CompilationDatabase::autoDetectFromDirectory(StringRef SourceDir,
     97                                              std::string &ErrorMessage) {
     98   SmallString<1024> AbsolutePath(getAbsolutePath(SourceDir));
     99 
    100   std::unique_ptr<CompilationDatabase> DB =
    101       findCompilationDatabaseFromDirectory(AbsolutePath, ErrorMessage);
    102 
    103   if (!DB)
    104     ErrorMessage = ("Could not auto-detect compilation database from directory \"" +
    105                    SourceDir + "\"\n" + ErrorMessage).str();
    106   return DB;
    107 }
    108 
    109 CompilationDatabasePlugin::~CompilationDatabasePlugin() {}
    110 
    111 namespace {
    112 // Helper for recursively searching through a chain of actions and collecting
    113 // all inputs, direct and indirect, of compile jobs.
    114 struct CompileJobAnalyzer {
    115   void run(const driver::Action *A) {
    116     runImpl(A, false);
    117   }
    118 
    119   SmallVector<std::string, 2> Inputs;
    120 
    121 private:
    122 
    123   void runImpl(const driver::Action *A, bool Collect) {
    124     bool CollectChildren = Collect;
    125     switch (A->getKind()) {
    126     case driver::Action::CompileJobClass:
    127       CollectChildren = true;
    128       break;
    129 
    130     case driver::Action::InputClass: {
    131       if (Collect) {
    132         const driver::InputAction *IA = cast<driver::InputAction>(A);
    133         Inputs.push_back(IA->getInputArg().getSpelling());
    134       }
    135     } break;
    136 
    137     default:
    138       // Don't care about others
    139       ;
    140     }
    141 
    142     for (driver::ActionList::const_iterator I = A->begin(), E = A->end();
    143          I != E; ++I)
    144       runImpl(*I, CollectChildren);
    145   }
    146 };
    147 
    148 // Special DiagnosticConsumer that looks for warn_drv_input_file_unused
    149 // diagnostics from the driver and collects the option strings for those unused
    150 // options.
    151 class UnusedInputDiagConsumer : public DiagnosticConsumer {
    152 public:
    153   UnusedInputDiagConsumer() : Other(nullptr) {}
    154 
    155   // Useful for debugging, chain diagnostics to another consumer after
    156   // recording for our own purposes.
    157   UnusedInputDiagConsumer(DiagnosticConsumer *Other) : Other(Other) {}
    158 
    159   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
    160                         const Diagnostic &Info) override {
    161     if (Info.getID() == clang::diag::warn_drv_input_file_unused) {
    162       // Arg 1 for this diagnostic is the option that didn't get used.
    163       UnusedInputs.push_back(Info.getArgStdStr(0));
    164     }
    165     if (Other)
    166       Other->HandleDiagnostic(DiagLevel, Info);
    167   }
    168 
    169   DiagnosticConsumer *Other;
    170   SmallVector<std::string, 2> UnusedInputs;
    171 };
    172 
    173 // Unary functor for asking "Given a StringRef S1, does there exist a string
    174 // S2 in Arr where S1 == S2?"
    175 struct MatchesAny {
    176   MatchesAny(ArrayRef<std::string> Arr) : Arr(Arr) {}
    177   bool operator() (StringRef S) {
    178     for (const std::string *I = Arr.begin(), *E = Arr.end(); I != E; ++I)
    179       if (*I == S)
    180         return true;
    181     return false;
    182   }
    183 private:
    184   ArrayRef<std::string> Arr;
    185 };
    186 } // namespace
    187 
    188 /// \brief Strips any positional args and possible argv[0] from a command-line
    189 /// provided by the user to construct a FixedCompilationDatabase.
    190 ///
    191 /// FixedCompilationDatabase requires a command line to be in this format as it
    192 /// constructs the command line for each file by appending the name of the file
    193 /// to be compiled. FixedCompilationDatabase also adds its own argv[0] to the
    194 /// start of the command line although its value is not important as it's just
    195 /// ignored by the Driver invoked by the ClangTool using the
    196 /// FixedCompilationDatabase.
    197 ///
    198 /// FIXME: This functionality should probably be made available by
    199 /// clang::driver::Driver although what the interface should look like is not
    200 /// clear.
    201 ///
    202 /// \param[in] Args Args as provided by the user.
    203 /// \return Resulting stripped command line.
    204 ///          \li true if successful.
    205 ///          \li false if \c Args cannot be used for compilation jobs (e.g.
    206 ///          contains an option like -E or -version).
    207 static bool stripPositionalArgs(std::vector<const char *> Args,
    208                                 std::vector<std::string> &Result) {
    209   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
    210   UnusedInputDiagConsumer DiagClient;
    211   DiagnosticsEngine Diagnostics(
    212       IntrusiveRefCntPtr<clang::DiagnosticIDs>(new DiagnosticIDs()),
    213       &*DiagOpts, &DiagClient, false);
    214 
    215   // The clang executable path isn't required since the jobs the driver builds
    216   // will not be executed.
    217   std::unique_ptr<driver::Driver> NewDriver(new driver::Driver(
    218       /* ClangExecutable= */ "", llvm::sys::getDefaultTargetTriple(),
    219       Diagnostics));
    220   NewDriver->setCheckInputsExist(false);
    221 
    222   // This becomes the new argv[0]. The value is actually not important as it
    223   // isn't used for invoking Tools.
    224   Args.insert(Args.begin(), "clang-tool");
    225 
    226   // By adding -c, we force the driver to treat compilation as the last phase.
    227   // It will then issue warnings via Diagnostics about un-used options that
    228   // would have been used for linking. If the user provided a compiler name as
    229   // the original argv[0], this will be treated as a linker input thanks to
    230   // insertng a new argv[0] above. All un-used options get collected by
    231   // UnusedInputdiagConsumer and get stripped out later.
    232   Args.push_back("-c");
    233 
    234   // Put a dummy C++ file on to ensure there's at least one compile job for the
    235   // driver to construct. If the user specified some other argument that
    236   // prevents compilation, e.g. -E or something like -version, we may still end
    237   // up with no jobs but then this is the user's fault.
    238   Args.push_back("placeholder.cpp");
    239 
    240   // Remove -no-integrated-as; it's not used for syntax checking,
    241   // and it confuses targets which don't support this option.
    242   Args.erase(std::remove_if(Args.begin(), Args.end(),
    243                             MatchesAny(std::string("-no-integrated-as"))),
    244              Args.end());
    245 
    246   const std::unique_ptr<driver::Compilation> Compilation(
    247       NewDriver->BuildCompilation(Args));
    248 
    249   const driver::JobList &Jobs = Compilation->getJobs();
    250 
    251   CompileJobAnalyzer CompileAnalyzer;
    252 
    253   for (const auto &Cmd : Jobs) {
    254     // Collect only for Assemble jobs. If we do all jobs we get duplicates
    255     // since Link jobs point to Assemble jobs as inputs.
    256     if (Cmd.getSource().getKind() == driver::Action::AssembleJobClass)
    257       CompileAnalyzer.run(&Cmd.getSource());
    258   }
    259 
    260   if (CompileAnalyzer.Inputs.empty()) {
    261     // No compile jobs found.
    262     // FIXME: Emit a warning of some kind?
    263     return false;
    264   }
    265 
    266   // Remove all compilation input files from the command line. This is
    267   // necessary so that getCompileCommands() can construct a command line for
    268   // each file.
    269   std::vector<const char *>::iterator End = std::remove_if(
    270       Args.begin(), Args.end(), MatchesAny(CompileAnalyzer.Inputs));
    271 
    272   // Remove all inputs deemed unused for compilation.
    273   End = std::remove_if(Args.begin(), End, MatchesAny(DiagClient.UnusedInputs));
    274 
    275   // Remove the -c add above as well. It will be at the end right now.
    276   assert(strcmp(*(End - 1), "-c") == 0);
    277   --End;
    278 
    279   Result = std::vector<std::string>(Args.begin() + 1, End);
    280   return true;
    281 }
    282 
    283 FixedCompilationDatabase *FixedCompilationDatabase::loadFromCommandLine(
    284     int &Argc, const char *const *Argv, Twine Directory) {
    285   const char *const *DoubleDash = std::find(Argv, Argv + Argc, StringRef("--"));
    286   if (DoubleDash == Argv + Argc)
    287     return nullptr;
    288   std::vector<const char *> CommandLine(DoubleDash + 1, Argv + Argc);
    289   Argc = DoubleDash - Argv;
    290 
    291   std::vector<std::string> StrippedArgs;
    292   if (!stripPositionalArgs(CommandLine, StrippedArgs))
    293     return nullptr;
    294   return new FixedCompilationDatabase(Directory, StrippedArgs);
    295 }
    296 
    297 FixedCompilationDatabase::
    298 FixedCompilationDatabase(Twine Directory, ArrayRef<std::string> CommandLine) {
    299   std::vector<std::string> ToolCommandLine(1, "clang-tool");
    300   ToolCommandLine.insert(ToolCommandLine.end(),
    301                          CommandLine.begin(), CommandLine.end());
    302   CompileCommands.emplace_back(Directory, StringRef(),
    303                                std::move(ToolCommandLine));
    304 }
    305 
    306 std::vector<CompileCommand>
    307 FixedCompilationDatabase::getCompileCommands(StringRef FilePath) const {
    308   std::vector<CompileCommand> Result(CompileCommands);
    309   Result[0].CommandLine.push_back(FilePath);
    310   Result[0].Filename = FilePath;
    311   return Result;
    312 }
    313 
    314 std::vector<std::string>
    315 FixedCompilationDatabase::getAllFiles() const {
    316   return std::vector<std::string>();
    317 }
    318 
    319 std::vector<CompileCommand>
    320 FixedCompilationDatabase::getAllCompileCommands() const {
    321   return std::vector<CompileCommand>();
    322 }
    323 
    324 namespace clang {
    325 namespace tooling {
    326 
    327 // This anchor is used to force the linker to link in the generated object file
    328 // and thus register the JSONCompilationDatabasePlugin.
    329 extern volatile int JSONAnchorSource;
    330 static int LLVM_ATTRIBUTE_UNUSED JSONAnchorDest = JSONAnchorSource;
    331 
    332 } // end namespace tooling
    333 } // end namespace clang
    334