1 //===--- Tooling.cpp - Running clang standalone tools ---------------------===//
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 implements functions to run clang tools standalone instead
11 //  of running them as a plugin.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Tooling/Tooling.h"
16 #include "clang/Driver/Compilation.h"
17 #include "clang/Driver/Driver.h"
18 #include "clang/Driver/Options.h"
19 #include "clang/Driver/Tool.h"
20 #include "clang/Driver/ToolChain.h"
21 #include "clang/Frontend/ASTUnit.h"
22 #include "clang/Frontend/CompilerInstance.h"
23 #include "clang/Frontend/FrontendDiagnostic.h"
24 #include "clang/Frontend/TextDiagnosticPrinter.h"
25 #include "clang/Lex/PreprocessorOptions.h"
26 #include "clang/Tooling/ArgumentsAdjusters.h"
27 #include "clang/Tooling/CompilationDatabase.h"
28 #include "llvm/ADT/STLExtras.h"
29 #include "llvm/Config/llvm-config.h"
30 #include "llvm/Option/ArgList.h"
31 #include "llvm/Option/Option.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/FileSystem.h"
34 #include "llvm/Support/Host.h"
35 #include "llvm/Support/Path.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include <utility>
38 
39 #define DEBUG_TYPE "clang-tooling"
40 
41 namespace clang {
42 namespace tooling {
43 
44 ToolAction::~ToolAction() {}
45 
46 FrontendActionFactory::~FrontendActionFactory() {}
47 
48 // FIXME: This file contains structural duplication with other parts of the
49 // code that sets up a compiler to run tools on it, and we should refactor
50 // it to be based on the same framework.
51 
52 /// \brief Builds a clang driver initialized for running clang tools.
53 static clang::driver::Driver *newDriver(
54     clang::DiagnosticsEngine *Diagnostics, const char *BinaryName,
55     IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
56   clang::driver::Driver *CompilerDriver =
57       new clang::driver::Driver(BinaryName, llvm::sys::getDefaultTargetTriple(),
58                                 *Diagnostics, std::move(VFS));
59   CompilerDriver->setTitle("clang_based_tool");
60   return CompilerDriver;
61 }
62 
63 /// \brief Retrieves the clang CC1 specific flags out of the compilation's jobs.
64 ///
65 /// Returns NULL on error.
66 static const llvm::opt::ArgStringList *getCC1Arguments(
67     clang::DiagnosticsEngine *Diagnostics,
68     clang::driver::Compilation *Compilation) {
69   // We expect to get back exactly one Command job, if we didn't something
70   // failed. Extract that job from the Compilation.
71   const clang::driver::JobList &Jobs = Compilation->getJobs();
72   if (Jobs.size() != 1 || !isa<clang::driver::Command>(*Jobs.begin())) {
73     SmallString<256> error_msg;
74     llvm::raw_svector_ostream error_stream(error_msg);
75     Jobs.Print(error_stream, "; ", true);
76     Diagnostics->Report(clang::diag::err_fe_expected_compiler_job)
77         << error_stream.str();
78     return nullptr;
79   }
80 
81   // The one job we find should be to invoke clang again.
82   const clang::driver::Command &Cmd =
83       cast<clang::driver::Command>(*Jobs.begin());
84   if (StringRef(Cmd.getCreator().getName()) != "clang") {
85     Diagnostics->Report(clang::diag::err_fe_expected_clang_command);
86     return nullptr;
87   }
88 
89   return &Cmd.getArguments();
90 }
91 
92 /// \brief Returns a clang build invocation initialized from the CC1 flags.
93 clang::CompilerInvocation *newInvocation(
94     clang::DiagnosticsEngine *Diagnostics,
95     const llvm::opt::ArgStringList &CC1Args) {
96   assert(!CC1Args.empty() && "Must at least contain the program name!");
97   clang::CompilerInvocation *Invocation = new clang::CompilerInvocation;
98   clang::CompilerInvocation::CreateFromArgs(
99       *Invocation, CC1Args.data() + 1, CC1Args.data() + CC1Args.size(),
100       *Diagnostics);
101   Invocation->getFrontendOpts().DisableFree = false;
102   Invocation->getCodeGenOpts().DisableFree = false;
103   return Invocation;
104 }
105 
106 bool runToolOnCode(clang::FrontendAction *ToolAction, const Twine &Code,
107                    const Twine &FileName,
108                    std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
109   return runToolOnCodeWithArgs(ToolAction, Code, std::vector<std::string>(),
110                                FileName, "clang-tool",
111                                std::move(PCHContainerOps));
112 }
113 
114 static std::vector<std::string>
115 getSyntaxOnlyToolArgs(const Twine &ToolName,
116                       const std::vector<std::string> &ExtraArgs,
117                       StringRef FileName) {
118   std::vector<std::string> Args;
119   Args.push_back(ToolName.str());
120   Args.push_back("-fsyntax-only");
121   Args.insert(Args.end(), ExtraArgs.begin(), ExtraArgs.end());
122   Args.push_back(FileName.str());
123   return Args;
124 }
125 
126 bool runToolOnCodeWithArgs(
127     clang::FrontendAction *ToolAction, const Twine &Code,
128     const std::vector<std::string> &Args, const Twine &FileName,
129     const Twine &ToolName,
130     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
131     const FileContentMappings &VirtualMappedFiles) {
132 
133   SmallString<16> FileNameStorage;
134   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
135   llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
136       new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
137   llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
138       new vfs::InMemoryFileSystem);
139   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
140   llvm::IntrusiveRefCntPtr<FileManager> Files(
141       new FileManager(FileSystemOptions(), OverlayFileSystem));
142   ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster();
143   ToolInvocation Invocation(
144       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
145       ToolAction, Files.get(),
146       std::move(PCHContainerOps));
147 
148   SmallString<1024> CodeStorage;
149   InMemoryFileSystem->addFile(FileNameRef, 0,
150                               llvm::MemoryBuffer::getMemBuffer(
151                                   Code.toNullTerminatedStringRef(CodeStorage)));
152 
153   for (auto &FilenameWithContent : VirtualMappedFiles) {
154     InMemoryFileSystem->addFile(
155         FilenameWithContent.first, 0,
156         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
157   }
158 
159   return Invocation.run();
160 }
161 
162 std::string getAbsolutePath(StringRef File) {
163   StringRef RelativePath(File);
164   // FIXME: Should '.\\' be accepted on Win32?
165   if (RelativePath.startswith("./")) {
166     RelativePath = RelativePath.substr(strlen("./"));
167   }
168 
169   SmallString<1024> AbsolutePath = RelativePath;
170   std::error_code EC = llvm::sys::fs::make_absolute(AbsolutePath);
171   assert(!EC);
172   (void)EC;
173   llvm::sys::path::native(AbsolutePath);
174   return AbsolutePath.str();
175 }
176 
177 void addTargetAndModeForProgramName(std::vector<std::string> &CommandLine,
178                                     StringRef InvokedAs) {
179   if (!CommandLine.empty() && !InvokedAs.empty()) {
180     bool AlreadyHasTarget = false;
181     bool AlreadyHasMode = false;
182     // Skip CommandLine[0].
183     for (auto Token = ++CommandLine.begin(); Token != CommandLine.end();
184          ++Token) {
185       StringRef TokenRef(*Token);
186       AlreadyHasTarget |=
187           (TokenRef == "-target" || TokenRef.startswith("-target="));
188       AlreadyHasMode |= (TokenRef == "--driver-mode" ||
189                          TokenRef.startswith("--driver-mode="));
190     }
191     auto TargetMode =
192         clang::driver::ToolChain::getTargetAndModeFromProgramName(InvokedAs);
193     if (!AlreadyHasMode && TargetMode.DriverMode) {
194       CommandLine.insert(++CommandLine.begin(), TargetMode.DriverMode);
195     }
196     if (!AlreadyHasTarget && TargetMode.TargetIsValid) {
197       CommandLine.insert(++CommandLine.begin(), {"-target",
198                                                  TargetMode.TargetPrefix});
199     }
200   }
201 }
202 
203 namespace {
204 
205 class SingleFrontendActionFactory : public FrontendActionFactory {
206   FrontendAction *Action;
207 
208 public:
209   SingleFrontendActionFactory(FrontendAction *Action) : Action(Action) {}
210 
211   FrontendAction *create() override { return Action; }
212 };
213 
214 }
215 
216 ToolInvocation::ToolInvocation(
217     std::vector<std::string> CommandLine, ToolAction *Action,
218     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
219     : CommandLine(std::move(CommandLine)), Action(Action), OwnsAction(false),
220       Files(Files), PCHContainerOps(std::move(PCHContainerOps)),
221       DiagConsumer(nullptr) {}
222 
223 ToolInvocation::ToolInvocation(
224     std::vector<std::string> CommandLine, FrontendAction *FAction,
225     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
226     : CommandLine(std::move(CommandLine)),
227       Action(new SingleFrontendActionFactory(FAction)), OwnsAction(true),
228       Files(Files), PCHContainerOps(std::move(PCHContainerOps)),
229       DiagConsumer(nullptr) {}
230 
231 ToolInvocation::~ToolInvocation() {
232   if (OwnsAction)
233     delete Action;
234 }
235 
236 void ToolInvocation::mapVirtualFile(StringRef FilePath, StringRef Content) {
237   SmallString<1024> PathStorage;
238   llvm::sys::path::native(FilePath, PathStorage);
239   MappedFileContents[PathStorage] = Content;
240 }
241 
242 bool ToolInvocation::run() {
243   std::vector<const char*> Argv;
244   for (const std::string &Str : CommandLine)
245     Argv.push_back(Str.c_str());
246   const char *const BinaryName = Argv[0];
247   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
248   unsigned MissingArgIndex, MissingArgCount;
249   std::unique_ptr<llvm::opt::OptTable> Opts = driver::createDriverOptTable();
250   llvm::opt::InputArgList ParsedArgs = Opts->ParseArgs(
251       ArrayRef<const char *>(Argv).slice(1), MissingArgIndex, MissingArgCount);
252   ParseDiagnosticArgs(*DiagOpts, ParsedArgs);
253   TextDiagnosticPrinter DiagnosticPrinter(
254       llvm::errs(), &*DiagOpts);
255   DiagnosticsEngine Diagnostics(
256       IntrusiveRefCntPtr<clang::DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
257       DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
258 
259   const std::unique_ptr<clang::driver::Driver> Driver(
260       newDriver(&Diagnostics, BinaryName, Files->getVirtualFileSystem()));
261   // Since the input might only be virtual, don't check whether it exists.
262   Driver->setCheckInputsExist(false);
263   const std::unique_ptr<clang::driver::Compilation> Compilation(
264       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
265   if (!Compilation)
266     return false;
267   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
268       &Diagnostics, Compilation.get());
269   if (!CC1Args) {
270     return false;
271   }
272   std::unique_ptr<clang::CompilerInvocation> Invocation(
273       newInvocation(&Diagnostics, *CC1Args));
274   // FIXME: remove this when all users have migrated!
275   for (const auto &It : MappedFileContents) {
276     // Inject the code as the given file name into the preprocessor options.
277     std::unique_ptr<llvm::MemoryBuffer> Input =
278         llvm::MemoryBuffer::getMemBuffer(It.getValue());
279     Invocation->getPreprocessorOpts().addRemappedFile(It.getKey(),
280                                                       Input.release());
281   }
282   return runInvocation(BinaryName, Compilation.get(), std::move(Invocation),
283                        std::move(PCHContainerOps));
284 }
285 
286 bool ToolInvocation::runInvocation(
287     const char *BinaryName, clang::driver::Compilation *Compilation,
288     std::shared_ptr<clang::CompilerInvocation> Invocation,
289     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
290   // Show the invocation, with -v.
291   if (Invocation->getHeaderSearchOpts().Verbose) {
292     llvm::errs() << "clang Invocation:\n";
293     Compilation->getJobs().Print(llvm::errs(), "\n", true);
294     llvm::errs() << "\n";
295   }
296 
297   return Action->runInvocation(std::move(Invocation), Files,
298                                std::move(PCHContainerOps), DiagConsumer);
299 }
300 
301 bool FrontendActionFactory::runInvocation(
302     std::shared_ptr<CompilerInvocation> Invocation, FileManager *Files,
303     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
304     DiagnosticConsumer *DiagConsumer) {
305   // Create a compiler instance to handle the actual work.
306   clang::CompilerInstance Compiler(std::move(PCHContainerOps));
307   Compiler.setInvocation(std::move(Invocation));
308   Compiler.setFileManager(Files);
309 
310   // The FrontendAction can have lifetime requirements for Compiler or its
311   // members, and we need to ensure it's deleted earlier than Compiler. So we
312   // pass it to an std::unique_ptr declared after the Compiler variable.
313   std::unique_ptr<FrontendAction> ScopedToolAction(create());
314 
315   // Create the compiler's actual diagnostics engine.
316   Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
317   if (!Compiler.hasDiagnostics())
318     return false;
319 
320   Compiler.createSourceManager(*Files);
321 
322   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
323 
324   Files->clearStatCaches();
325   return Success;
326 }
327 
328 ClangTool::ClangTool(const CompilationDatabase &Compilations,
329                      ArrayRef<std::string> SourcePaths,
330                      std::shared_ptr<PCHContainerOperations> PCHContainerOps)
331     : Compilations(Compilations), SourcePaths(SourcePaths),
332       PCHContainerOps(std::move(PCHContainerOps)),
333       OverlayFileSystem(new vfs::OverlayFileSystem(vfs::getRealFileSystem())),
334       InMemoryFileSystem(new vfs::InMemoryFileSystem),
335       Files(new FileManager(FileSystemOptions(), OverlayFileSystem)),
336       DiagConsumer(nullptr) {
337   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
338   appendArgumentsAdjuster(getClangStripOutputAdjuster());
339   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
340   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
341 }
342 
343 ClangTool::~ClangTool() {}
344 
345 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
346   MappedFileContents.push_back(std::make_pair(FilePath, Content));
347 }
348 
349 void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
350   if (ArgsAdjuster)
351     ArgsAdjuster =
352         combineAdjusters(std::move(ArgsAdjuster), std::move(Adjuster));
353   else
354     ArgsAdjuster = std::move(Adjuster);
355 }
356 
357 void ClangTool::clearArgumentsAdjusters() {
358   ArgsAdjuster = nullptr;
359 }
360 
361 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
362                               void *MainAddr) {
363   // Allow users to override the resource dir.
364   for (StringRef Arg : Args)
365     if (Arg.startswith("-resource-dir"))
366       return;
367 
368   // If there's no override in place add our resource dir.
369   Args.push_back("-resource-dir=" +
370                  CompilerInvocation::GetResourcesPath(Argv0, MainAddr));
371 }
372 
373 int ClangTool::run(ToolAction *Action) {
374   // Exists solely for the purpose of lookup of the resource path.
375   // This just needs to be some symbol in the binary.
376   static int StaticSymbol;
377 
378   llvm::SmallString<128> InitialDirectory;
379   if (std::error_code EC = llvm::sys::fs::current_path(InitialDirectory))
380     llvm::report_fatal_error("Cannot detect current path: " +
381                              Twine(EC.message()));
382 
383   // First insert all absolute paths into the in-memory VFS. These are global
384   // for all compile commands.
385   if (SeenWorkingDirectories.insert("/").second)
386     for (const auto &MappedFile : MappedFileContents)
387       if (llvm::sys::path::is_absolute(MappedFile.first))
388         InMemoryFileSystem->addFile(
389             MappedFile.first, 0,
390             llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
391 
392   bool ProcessingFailed = false;
393   for (const auto &SourcePath : SourcePaths) {
394     std::string File(getAbsolutePath(SourcePath));
395 
396     // Currently implementations of CompilationDatabase::getCompileCommands can
397     // change the state of the file system (e.g.  prepare generated headers), so
398     // this method needs to run right before we invoke the tool, as the next
399     // file may require a different (incompatible) state of the file system.
400     //
401     // FIXME: Make the compilation database interface more explicit about the
402     // requirements to the order of invocation of its members.
403     std::vector<CompileCommand> CompileCommandsForFile =
404         Compilations.getCompileCommands(File);
405     if (CompileCommandsForFile.empty()) {
406       // FIXME: There are two use cases here: doing a fuzzy
407       // "find . -name '*.cc' |xargs tool" match, where as a user I don't care
408       // about the .cc files that were not found, and the use case where I
409       // specify all files I want to run over explicitly, where this should
410       // be an error. We'll want to add an option for this.
411       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
412       continue;
413     }
414     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
415       // FIXME: chdir is thread hostile; on the other hand, creating the same
416       // behavior as chdir is complex: chdir resolves the path once, thus
417       // guaranteeing that all subsequent relative path operations work
418       // on the same path the original chdir resulted in. This makes a
419       // difference for example on network filesystems, where symlinks might be
420       // switched during runtime of the tool. Fixing this depends on having a
421       // file system abstraction that allows openat() style interactions.
422       if (OverlayFileSystem->setCurrentWorkingDirectory(
423               CompileCommand.Directory))
424         llvm::report_fatal_error("Cannot chdir into \"" +
425                                  Twine(CompileCommand.Directory) + "\n!");
426 
427       // Now fill the in-memory VFS with the relative file mappings so it will
428       // have the correct relative paths. We never remove mappings but that
429       // should be fine.
430       if (SeenWorkingDirectories.insert(CompileCommand.Directory).second)
431         for (const auto &MappedFile : MappedFileContents)
432           if (!llvm::sys::path::is_absolute(MappedFile.first))
433             InMemoryFileSystem->addFile(
434                 MappedFile.first, 0,
435                 llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
436 
437       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
438       if (ArgsAdjuster)
439         CommandLine = ArgsAdjuster(CommandLine, CompileCommand.Filename);
440       assert(!CommandLine.empty());
441 
442       // Add the resource dir based on the binary of this tool. argv[0] in the
443       // compilation database may refer to a different compiler and we want to
444       // pick up the very same standard library that compiler is using. The
445       // builtin headers in the resource dir need to match the exact clang
446       // version the tool is using.
447       // FIXME: On linux, GetMainExecutable is independent of the value of the
448       // first argument, thus allowing ClangTool and runToolOnCode to just
449       // pass in made-up names here. Make sure this works on other platforms.
450       injectResourceDir(CommandLine, "clang_tool", &StaticSymbol);
451 
452       // FIXME: We need a callback mechanism for the tool writer to output a
453       // customized message for each file.
454       DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
455       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
456                                 PCHContainerOps);
457       Invocation.setDiagnosticConsumer(DiagConsumer);
458 
459       if (!Invocation.run()) {
460         // FIXME: Diagnostics should be used instead.
461         llvm::errs() << "Error while processing " << File << ".\n";
462         ProcessingFailed = true;
463       }
464       // Return to the initial directory to correctly resolve next file by
465       // relative path.
466       if (OverlayFileSystem->setCurrentWorkingDirectory(InitialDirectory.c_str()))
467         llvm::report_fatal_error("Cannot chdir into \"" +
468                                  Twine(InitialDirectory) + "\n!");
469     }
470   }
471   return ProcessingFailed ? 1 : 0;
472 }
473 
474 namespace {
475 
476 class ASTBuilderAction : public ToolAction {
477   std::vector<std::unique_ptr<ASTUnit>> &ASTs;
478 
479 public:
480   ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}
481 
482   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
483                      FileManager *Files,
484                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
485                      DiagnosticConsumer *DiagConsumer) override {
486     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
487         Invocation, std::move(PCHContainerOps),
488         CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
489                                             DiagConsumer,
490                                             /*ShouldOwnClient=*/false),
491         Files);
492     if (!AST)
493       return false;
494 
495     ASTs.push_back(std::move(AST));
496     return true;
497   }
498 };
499 }
500 
501 int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
502   ASTBuilderAction Action(ASTs);
503   return run(&Action);
504 }
505 
506 std::unique_ptr<ASTUnit>
507 buildASTFromCode(const Twine &Code, const Twine &FileName,
508                  std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
509   return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName,
510                                   "clang-tool", std::move(PCHContainerOps));
511 }
512 
513 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
514     const Twine &Code, const std::vector<std::string> &Args,
515     const Twine &FileName, const Twine &ToolName,
516     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
517     ArgumentsAdjuster Adjuster) {
518   SmallString<16> FileNameStorage;
519   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
520 
521   std::vector<std::unique_ptr<ASTUnit>> ASTs;
522   ASTBuilderAction Action(ASTs);
523   llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
524       new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
525   llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
526       new vfs::InMemoryFileSystem);
527   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
528   llvm::IntrusiveRefCntPtr<FileManager> Files(
529       new FileManager(FileSystemOptions(), OverlayFileSystem));
530 
531   ToolInvocation Invocation(
532       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
533       &Action, Files.get(), std::move(PCHContainerOps));
534 
535   SmallString<1024> CodeStorage;
536   InMemoryFileSystem->addFile(FileNameRef, 0,
537                               llvm::MemoryBuffer::getMemBuffer(
538                                   Code.toNullTerminatedStringRef(CodeStorage)));
539   if (!Invocation.run())
540     return nullptr;
541 
542   assert(ASTs.size() == 1);
543   return std::move(ASTs[0]);
544 }
545 
546 } // end namespace tooling
547 } // end namespace clang
548