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.second.empty()) {
194       CommandLine.insert(++CommandLine.begin(), TargetMode.second);
195     }
196     if (!AlreadyHasTarget && !TargetMode.first.empty()) {
197       CommandLine.insert(++CommandLine.begin(), {"-target", TargetMode.first});
198     }
199   }
200 }
201 
202 namespace {
203 
204 class SingleFrontendActionFactory : public FrontendActionFactory {
205   FrontendAction *Action;
206 
207 public:
208   SingleFrontendActionFactory(FrontendAction *Action) : Action(Action) {}
209 
210   FrontendAction *create() override { return Action; }
211 };
212 
213 }
214 
215 ToolInvocation::ToolInvocation(
216     std::vector<std::string> CommandLine, ToolAction *Action,
217     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
218     : CommandLine(std::move(CommandLine)), Action(Action), OwnsAction(false),
219       Files(Files), PCHContainerOps(std::move(PCHContainerOps)),
220       DiagConsumer(nullptr) {}
221 
222 ToolInvocation::ToolInvocation(
223     std::vector<std::string> CommandLine, FrontendAction *FAction,
224     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
225     : CommandLine(std::move(CommandLine)),
226       Action(new SingleFrontendActionFactory(FAction)), OwnsAction(true),
227       Files(Files), PCHContainerOps(std::move(PCHContainerOps)),
228       DiagConsumer(nullptr) {}
229 
230 ToolInvocation::~ToolInvocation() {
231   if (OwnsAction)
232     delete Action;
233 }
234 
235 void ToolInvocation::mapVirtualFile(StringRef FilePath, StringRef Content) {
236   SmallString<1024> PathStorage;
237   llvm::sys::path::native(FilePath, PathStorage);
238   MappedFileContents[PathStorage] = Content;
239 }
240 
241 bool ToolInvocation::run() {
242   std::vector<const char*> Argv;
243   for (const std::string &Str : CommandLine)
244     Argv.push_back(Str.c_str());
245   const char *const BinaryName = Argv[0];
246   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
247   unsigned MissingArgIndex, MissingArgCount;
248   std::unique_ptr<llvm::opt::OptTable> Opts = driver::createDriverOptTable();
249   llvm::opt::InputArgList ParsedArgs = Opts->ParseArgs(
250       ArrayRef<const char *>(Argv).slice(1), MissingArgIndex, MissingArgCount);
251   ParseDiagnosticArgs(*DiagOpts, ParsedArgs);
252   TextDiagnosticPrinter DiagnosticPrinter(
253       llvm::errs(), &*DiagOpts);
254   DiagnosticsEngine Diagnostics(
255       IntrusiveRefCntPtr<clang::DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
256       DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
257 
258   const std::unique_ptr<clang::driver::Driver> Driver(
259       newDriver(&Diagnostics, BinaryName, Files->getVirtualFileSystem()));
260   // Since the input might only be virtual, don't check whether it exists.
261   Driver->setCheckInputsExist(false);
262   const std::unique_ptr<clang::driver::Compilation> Compilation(
263       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
264   if (!Compilation)
265     return false;
266   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
267       &Diagnostics, Compilation.get());
268   if (!CC1Args) {
269     return false;
270   }
271   std::unique_ptr<clang::CompilerInvocation> Invocation(
272       newInvocation(&Diagnostics, *CC1Args));
273   // FIXME: remove this when all users have migrated!
274   for (const auto &It : MappedFileContents) {
275     // Inject the code as the given file name into the preprocessor options.
276     std::unique_ptr<llvm::MemoryBuffer> Input =
277         llvm::MemoryBuffer::getMemBuffer(It.getValue());
278     Invocation->getPreprocessorOpts().addRemappedFile(It.getKey(),
279                                                       Input.release());
280   }
281   return runInvocation(BinaryName, Compilation.get(), std::move(Invocation),
282                        std::move(PCHContainerOps));
283 }
284 
285 bool ToolInvocation::runInvocation(
286     const char *BinaryName, clang::driver::Compilation *Compilation,
287     std::shared_ptr<clang::CompilerInvocation> Invocation,
288     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
289   // Show the invocation, with -v.
290   if (Invocation->getHeaderSearchOpts().Verbose) {
291     llvm::errs() << "clang Invocation:\n";
292     Compilation->getJobs().Print(llvm::errs(), "\n", true);
293     llvm::errs() << "\n";
294   }
295 
296   return Action->runInvocation(std::move(Invocation), Files,
297                                std::move(PCHContainerOps), DiagConsumer);
298 }
299 
300 bool FrontendActionFactory::runInvocation(
301     std::shared_ptr<CompilerInvocation> Invocation, FileManager *Files,
302     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
303     DiagnosticConsumer *DiagConsumer) {
304   // Create a compiler instance to handle the actual work.
305   clang::CompilerInstance Compiler(std::move(PCHContainerOps));
306   Compiler.setInvocation(std::move(Invocation));
307   Compiler.setFileManager(Files);
308 
309   // The FrontendAction can have lifetime requirements for Compiler or its
310   // members, and we need to ensure it's deleted earlier than Compiler. So we
311   // pass it to an std::unique_ptr declared after the Compiler variable.
312   std::unique_ptr<FrontendAction> ScopedToolAction(create());
313 
314   // Create the compiler's actual diagnostics engine.
315   Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
316   if (!Compiler.hasDiagnostics())
317     return false;
318 
319   Compiler.createSourceManager(*Files);
320 
321   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
322 
323   Files->clearStatCaches();
324   return Success;
325 }
326 
327 ClangTool::ClangTool(const CompilationDatabase &Compilations,
328                      ArrayRef<std::string> SourcePaths,
329                      std::shared_ptr<PCHContainerOperations> PCHContainerOps)
330     : Compilations(Compilations), SourcePaths(SourcePaths),
331       PCHContainerOps(std::move(PCHContainerOps)),
332       OverlayFileSystem(new vfs::OverlayFileSystem(vfs::getRealFileSystem())),
333       InMemoryFileSystem(new vfs::InMemoryFileSystem),
334       Files(new FileManager(FileSystemOptions(), OverlayFileSystem)),
335       DiagConsumer(nullptr) {
336   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
337   appendArgumentsAdjuster(getClangStripOutputAdjuster());
338   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
339   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
340 }
341 
342 ClangTool::~ClangTool() {}
343 
344 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
345   MappedFileContents.push_back(std::make_pair(FilePath, Content));
346 }
347 
348 void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
349   if (ArgsAdjuster)
350     ArgsAdjuster =
351         combineAdjusters(std::move(ArgsAdjuster), std::move(Adjuster));
352   else
353     ArgsAdjuster = std::move(Adjuster);
354 }
355 
356 void ClangTool::clearArgumentsAdjusters() {
357   ArgsAdjuster = nullptr;
358 }
359 
360 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
361                               void *MainAddr) {
362   // Allow users to override the resource dir.
363   for (StringRef Arg : Args)
364     if (Arg.startswith("-resource-dir"))
365       return;
366 
367   // If there's no override in place add our resource dir.
368   Args.push_back("-resource-dir=" +
369                  CompilerInvocation::GetResourcesPath(Argv0, MainAddr));
370 }
371 
372 int ClangTool::run(ToolAction *Action) {
373   // Exists solely for the purpose of lookup of the resource path.
374   // This just needs to be some symbol in the binary.
375   static int StaticSymbol;
376 
377   llvm::SmallString<128> InitialDirectory;
378   if (std::error_code EC = llvm::sys::fs::current_path(InitialDirectory))
379     llvm::report_fatal_error("Cannot detect current path: " +
380                              Twine(EC.message()));
381 
382   // First insert all absolute paths into the in-memory VFS. These are global
383   // for all compile commands.
384   if (SeenWorkingDirectories.insert("/").second)
385     for (const auto &MappedFile : MappedFileContents)
386       if (llvm::sys::path::is_absolute(MappedFile.first))
387         InMemoryFileSystem->addFile(
388             MappedFile.first, 0,
389             llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
390 
391   bool ProcessingFailed = false;
392   for (const auto &SourcePath : SourcePaths) {
393     std::string File(getAbsolutePath(SourcePath));
394 
395     // Currently implementations of CompilationDatabase::getCompileCommands can
396     // change the state of the file system (e.g.  prepare generated headers), so
397     // this method needs to run right before we invoke the tool, as the next
398     // file may require a different (incompatible) state of the file system.
399     //
400     // FIXME: Make the compilation database interface more explicit about the
401     // requirements to the order of invocation of its members.
402     std::vector<CompileCommand> CompileCommandsForFile =
403         Compilations.getCompileCommands(File);
404     if (CompileCommandsForFile.empty()) {
405       // FIXME: There are two use cases here: doing a fuzzy
406       // "find . -name '*.cc' |xargs tool" match, where as a user I don't care
407       // about the .cc files that were not found, and the use case where I
408       // specify all files I want to run over explicitly, where this should
409       // be an error. We'll want to add an option for this.
410       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
411       continue;
412     }
413     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
414       // FIXME: chdir is thread hostile; on the other hand, creating the same
415       // behavior as chdir is complex: chdir resolves the path once, thus
416       // guaranteeing that all subsequent relative path operations work
417       // on the same path the original chdir resulted in. This makes a
418       // difference for example on network filesystems, where symlinks might be
419       // switched during runtime of the tool. Fixing this depends on having a
420       // file system abstraction that allows openat() style interactions.
421       if (OverlayFileSystem->setCurrentWorkingDirectory(
422               CompileCommand.Directory))
423         llvm::report_fatal_error("Cannot chdir into \"" +
424                                  Twine(CompileCommand.Directory) + "\n!");
425 
426       // Now fill the in-memory VFS with the relative file mappings so it will
427       // have the correct relative paths. We never remove mappings but that
428       // should be fine.
429       if (SeenWorkingDirectories.insert(CompileCommand.Directory).second)
430         for (const auto &MappedFile : MappedFileContents)
431           if (!llvm::sys::path::is_absolute(MappedFile.first))
432             InMemoryFileSystem->addFile(
433                 MappedFile.first, 0,
434                 llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
435 
436       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
437       if (ArgsAdjuster)
438         CommandLine = ArgsAdjuster(CommandLine, CompileCommand.Filename);
439       assert(!CommandLine.empty());
440 
441       // Add the resource dir based on the binary of this tool. argv[0] in the
442       // compilation database may refer to a different compiler and we want to
443       // pick up the very same standard library that compiler is using. The
444       // builtin headers in the resource dir need to match the exact clang
445       // version the tool is using.
446       // FIXME: On linux, GetMainExecutable is independent of the value of the
447       // first argument, thus allowing ClangTool and runToolOnCode to just
448       // pass in made-up names here. Make sure this works on other platforms.
449       injectResourceDir(CommandLine, "clang_tool", &StaticSymbol);
450 
451       // FIXME: We need a callback mechanism for the tool writer to output a
452       // customized message for each file.
453       DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
454       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
455                                 PCHContainerOps);
456       Invocation.setDiagnosticConsumer(DiagConsumer);
457 
458       if (!Invocation.run()) {
459         // FIXME: Diagnostics should be used instead.
460         llvm::errs() << "Error while processing " << File << ".\n";
461         ProcessingFailed = true;
462       }
463       // Return to the initial directory to correctly resolve next file by
464       // relative path.
465       if (OverlayFileSystem->setCurrentWorkingDirectory(InitialDirectory.c_str()))
466         llvm::report_fatal_error("Cannot chdir into \"" +
467                                  Twine(InitialDirectory) + "\n!");
468     }
469   }
470   return ProcessingFailed ? 1 : 0;
471 }
472 
473 namespace {
474 
475 class ASTBuilderAction : public ToolAction {
476   std::vector<std::unique_ptr<ASTUnit>> &ASTs;
477 
478 public:
479   ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}
480 
481   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
482                      FileManager *Files,
483                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
484                      DiagnosticConsumer *DiagConsumer) override {
485     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
486         Invocation, std::move(PCHContainerOps),
487         CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
488                                             DiagConsumer,
489                                             /*ShouldOwnClient=*/false),
490         Files);
491     if (!AST)
492       return false;
493 
494     ASTs.push_back(std::move(AST));
495     return true;
496   }
497 };
498 }
499 
500 int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
501   ASTBuilderAction Action(ASTs);
502   return run(&Action);
503 }
504 
505 std::unique_ptr<ASTUnit>
506 buildASTFromCode(const Twine &Code, const Twine &FileName,
507                  std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
508   return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName,
509                                   "clang-tool", std::move(PCHContainerOps));
510 }
511 
512 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
513     const Twine &Code, const std::vector<std::string> &Args,
514     const Twine &FileName, const Twine &ToolName,
515     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
516     ArgumentsAdjuster Adjuster) {
517   SmallString<16> FileNameStorage;
518   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
519 
520   std::vector<std::unique_ptr<ASTUnit>> ASTs;
521   ASTBuilderAction Action(ASTs);
522   llvm::IntrusiveRefCntPtr<vfs::OverlayFileSystem> OverlayFileSystem(
523       new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
524   llvm::IntrusiveRefCntPtr<vfs::InMemoryFileSystem> InMemoryFileSystem(
525       new vfs::InMemoryFileSystem);
526   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
527   llvm::IntrusiveRefCntPtr<FileManager> Files(
528       new FileManager(FileSystemOptions(), OverlayFileSystem));
529 
530   ToolInvocation Invocation(
531       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
532       &Action, Files.get(), std::move(PCHContainerOps));
533 
534   SmallString<1024> CodeStorage;
535   InMemoryFileSystem->addFile(FileNameRef, 0,
536                               llvm::MemoryBuffer::getMemBuffer(
537                                   Code.toNullTerminatedStringRef(CodeStorage)));
538   if (!Invocation.run())
539     return nullptr;
540 
541   assert(ASTs.size() == 1);
542   return std::move(ASTs[0]);
543 }
544 
545 } // end namespace tooling
546 } // end namespace clang
547