1 //===- Tooling.cpp - Running clang standalone tools -----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 //  This file implements functions to run clang tools standalone instead
10 //  of running them as a plugin.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Tooling/Tooling.h"
15 #include "clang/Basic/Diagnostic.h"
16 #include "clang/Basic/DiagnosticIDs.h"
17 #include "clang/Basic/DiagnosticOptions.h"
18 #include "clang/Basic/FileManager.h"
19 #include "clang/Basic/FileSystemOptions.h"
20 #include "clang/Basic/LLVM.h"
21 #include "clang/Driver/Compilation.h"
22 #include "clang/Driver/Driver.h"
23 #include "clang/Driver/Job.h"
24 #include "clang/Driver/Options.h"
25 #include "clang/Driver/Tool.h"
26 #include "clang/Driver/ToolChain.h"
27 #include "clang/Frontend/ASTUnit.h"
28 #include "clang/Frontend/CompilerInstance.h"
29 #include "clang/Frontend/CompilerInvocation.h"
30 #include "clang/Frontend/FrontendDiagnostic.h"
31 #include "clang/Frontend/FrontendOptions.h"
32 #include "clang/Frontend/TextDiagnosticPrinter.h"
33 #include "clang/Lex/HeaderSearchOptions.h"
34 #include "clang/Lex/PreprocessorOptions.h"
35 #include "clang/Tooling/ArgumentsAdjusters.h"
36 #include "clang/Tooling/CompilationDatabase.h"
37 #include "llvm/ADT/ArrayRef.h"
38 #include "llvm/ADT/IntrusiveRefCntPtr.h"
39 #include "llvm/ADT/SmallString.h"
40 #include "llvm/ADT/StringRef.h"
41 #include "llvm/ADT/Twine.h"
42 #include "llvm/Option/ArgList.h"
43 #include "llvm/Option/OptTable.h"
44 #include "llvm/Option/Option.h"
45 #include "llvm/Support/Casting.h"
46 #include "llvm/Support/Debug.h"
47 #include "llvm/Support/ErrorHandling.h"
48 #include "llvm/Support/FileSystem.h"
49 #include "llvm/Support/Host.h"
50 #include "llvm/Support/MemoryBuffer.h"
51 #include "llvm/Support/Path.h"
52 #include "llvm/Support/VirtualFileSystem.h"
53 #include "llvm/Support/raw_ostream.h"
54 #include <cassert>
55 #include <cstring>
56 #include <memory>
57 #include <string>
58 #include <system_error>
59 #include <utility>
60 #include <vector>
61 
62 #define DEBUG_TYPE "clang-tooling"
63 
64 using namespace clang;
65 using namespace tooling;
66 
67 ToolAction::~ToolAction() = default;
68 
69 FrontendActionFactory::~FrontendActionFactory() = default;
70 
71 // FIXME: This file contains structural duplication with other parts of the
72 // code that sets up a compiler to run tools on it, and we should refactor
73 // it to be based on the same framework.
74 
75 /// Builds a clang driver initialized for running clang tools.
76 static driver::Driver *
77 newDriver(DiagnosticsEngine *Diagnostics, const char *BinaryName,
78           IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
79   driver::Driver *CompilerDriver =
80       new driver::Driver(BinaryName, llvm::sys::getDefaultTargetTriple(),
81                          *Diagnostics, "clang LLVM compiler", std::move(VFS));
82   CompilerDriver->setTitle("clang_based_tool");
83   return CompilerDriver;
84 }
85 
86 /// Decide whether extra compiler frontend commands can be ignored.
87 static bool ignoreExtraCC1Commands(const driver::Compilation *Compilation) {
88   const driver::JobList &Jobs = Compilation->getJobs();
89   const driver::ActionList &Actions = Compilation->getActions();
90 
91   bool OffloadCompilation = false;
92 
93   // Jobs and Actions look very different depending on whether the Clang tool
94   // injected -fsyntax-only or not. Try to handle both cases here.
95 
96   for (const auto &Job : Jobs)
97     if (StringRef(Job.getExecutable()) == "clang-offload-bundler")
98       OffloadCompilation = true;
99 
100   if (Jobs.size() > 1) {
101     for (auto *A : Actions){
102       // On MacOSX real actions may end up being wrapped in BindArchAction
103       if (isa<driver::BindArchAction>(A))
104         A = *A->input_begin();
105       if (isa<driver::OffloadAction>(A)) {
106         // Offload compilation has 2 top-level actions, one (at the front) is
107         // the original host compilation and the other is offload action
108         // composed of at least one device compilation. For such case, general
109         // tooling will consider host-compilation only. For tooling on device
110         // compilation, device compilation only option, such as
111         // `--cuda-device-only`, needs specifying.
112         assert(Actions.size() > 1);
113         assert(
114             isa<driver::CompileJobAction>(Actions.front()) ||
115             // On MacOSX real actions may end up being wrapped in
116             // BindArchAction.
117             (isa<driver::BindArchAction>(Actions.front()) &&
118              isa<driver::CompileJobAction>(*Actions.front()->input_begin())));
119         OffloadCompilation = true;
120         break;
121       }
122     }
123   }
124 
125   return OffloadCompilation;
126 }
127 
128 namespace clang {
129 namespace tooling {
130 
131 const llvm::opt::ArgStringList *
132 getCC1Arguments(DiagnosticsEngine *Diagnostics,
133                 driver::Compilation *Compilation) {
134   const driver::JobList &Jobs = Compilation->getJobs();
135 
136   auto IsCC1Command = [](const driver::Command &Cmd) {
137     return StringRef(Cmd.getCreator().getName()) == "clang";
138   };
139 
140   auto IsSrcFile = [](const driver::InputInfo &II) {
141     return isSrcFile(II.getType());
142   };
143 
144   llvm::SmallVector<const driver::Command *, 1> CC1Jobs;
145   for (const driver::Command &Job : Jobs)
146     if (IsCC1Command(Job) && llvm::all_of(Job.getInputInfos(), IsSrcFile))
147       CC1Jobs.push_back(&Job);
148 
149   if (CC1Jobs.empty() ||
150       (CC1Jobs.size() > 1 && !ignoreExtraCC1Commands(Compilation))) {
151     SmallString<256> error_msg;
152     llvm::raw_svector_ostream error_stream(error_msg);
153     Jobs.Print(error_stream, "; ", true);
154     Diagnostics->Report(diag::err_fe_expected_compiler_job)
155         << error_stream.str();
156     return nullptr;
157   }
158 
159   return &CC1Jobs[0]->getArguments();
160 }
161 
162 /// Returns a clang build invocation initialized from the CC1 flags.
163 CompilerInvocation *newInvocation(DiagnosticsEngine *Diagnostics,
164                                   ArrayRef<const char *> CC1Args,
165                                   const char *const BinaryName) {
166   assert(!CC1Args.empty() && "Must at least contain the program name!");
167   CompilerInvocation *Invocation = new CompilerInvocation;
168   CompilerInvocation::CreateFromArgs(*Invocation, CC1Args, *Diagnostics,
169                                      BinaryName);
170   Invocation->getFrontendOpts().DisableFree = false;
171   Invocation->getCodeGenOpts().DisableFree = false;
172   return Invocation;
173 }
174 
175 bool runToolOnCode(std::unique_ptr<FrontendAction> ToolAction,
176                    const Twine &Code, const Twine &FileName,
177                    std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
178   return runToolOnCodeWithArgs(std::move(ToolAction), Code,
179                                std::vector<std::string>(), FileName,
180                                "clang-tool", std::move(PCHContainerOps));
181 }
182 
183 } // namespace tooling
184 } // namespace clang
185 
186 static std::vector<std::string>
187 getSyntaxOnlyToolArgs(const Twine &ToolName,
188                       const std::vector<std::string> &ExtraArgs,
189                       StringRef FileName) {
190   std::vector<std::string> Args;
191   Args.push_back(ToolName.str());
192   Args.push_back("-fsyntax-only");
193   Args.insert(Args.end(), ExtraArgs.begin(), ExtraArgs.end());
194   Args.push_back(FileName.str());
195   return Args;
196 }
197 
198 namespace clang {
199 namespace tooling {
200 
201 bool runToolOnCodeWithArgs(
202     std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
203     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
204     const std::vector<std::string> &Args, const Twine &FileName,
205     const Twine &ToolName,
206     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
207   SmallString<16> FileNameStorage;
208   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
209 
210   llvm::IntrusiveRefCntPtr<FileManager> Files(
211       new FileManager(FileSystemOptions(), VFS));
212   ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster();
213   ToolInvocation Invocation(
214       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
215       std::move(ToolAction), Files.get(), std::move(PCHContainerOps));
216   return Invocation.run();
217 }
218 
219 bool runToolOnCodeWithArgs(
220     std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
221     const std::vector<std::string> &Args, const Twine &FileName,
222     const Twine &ToolName,
223     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
224     const FileContentMappings &VirtualMappedFiles) {
225   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
226       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
227   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
228       new llvm::vfs::InMemoryFileSystem);
229   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
230 
231   SmallString<1024> CodeStorage;
232   InMemoryFileSystem->addFile(FileName, 0,
233                               llvm::MemoryBuffer::getMemBuffer(
234                                   Code.toNullTerminatedStringRef(CodeStorage)));
235 
236   for (auto &FilenameWithContent : VirtualMappedFiles) {
237     InMemoryFileSystem->addFile(
238         FilenameWithContent.first, 0,
239         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
240   }
241 
242   return runToolOnCodeWithArgs(std::move(ToolAction), Code, OverlayFileSystem,
243                                Args, FileName, ToolName);
244 }
245 
246 llvm::Expected<std::string> getAbsolutePath(llvm::vfs::FileSystem &FS,
247                                             StringRef File) {
248   StringRef RelativePath(File);
249   // FIXME: Should '.\\' be accepted on Win32?
250   if (RelativePath.startswith("./")) {
251     RelativePath = RelativePath.substr(strlen("./"));
252   }
253 
254   SmallString<1024> AbsolutePath = RelativePath;
255   if (auto EC = FS.makeAbsolute(AbsolutePath))
256     return llvm::errorCodeToError(EC);
257   llvm::sys::path::native(AbsolutePath);
258   return std::string(AbsolutePath.str());
259 }
260 
261 std::string getAbsolutePath(StringRef File) {
262   return llvm::cantFail(getAbsolutePath(*llvm::vfs::getRealFileSystem(), File));
263 }
264 
265 void addTargetAndModeForProgramName(std::vector<std::string> &CommandLine,
266                                     StringRef InvokedAs) {
267   if (CommandLine.empty() || InvokedAs.empty())
268     return;
269   const auto &Table = driver::getDriverOptTable();
270   // --target=X
271   const std::string TargetOPT =
272       Table.getOption(driver::options::OPT_target).getPrefixedName();
273   // -target X
274   const std::string TargetOPTLegacy =
275       Table.getOption(driver::options::OPT_target_legacy_spelling)
276           .getPrefixedName();
277   // --driver-mode=X
278   const std::string DriverModeOPT =
279       Table.getOption(driver::options::OPT_driver_mode).getPrefixedName();
280   auto TargetMode =
281       driver::ToolChain::getTargetAndModeFromProgramName(InvokedAs);
282   // No need to search for target args if we don't have a target/mode to insert.
283   bool ShouldAddTarget = TargetMode.TargetIsValid;
284   bool ShouldAddMode = TargetMode.DriverMode != nullptr;
285   // Skip CommandLine[0].
286   for (auto Token = ++CommandLine.begin(); Token != CommandLine.end();
287        ++Token) {
288     StringRef TokenRef(*Token);
289     ShouldAddTarget = ShouldAddTarget && !TokenRef.startswith(TargetOPT) &&
290                       !TokenRef.equals(TargetOPTLegacy);
291     ShouldAddMode = ShouldAddMode && !TokenRef.startswith(DriverModeOPT);
292   }
293   if (ShouldAddMode) {
294     CommandLine.insert(++CommandLine.begin(), TargetMode.DriverMode);
295   }
296   if (ShouldAddTarget) {
297     CommandLine.insert(++CommandLine.begin(),
298                        TargetOPT + TargetMode.TargetPrefix);
299   }
300 }
301 
302 } // namespace tooling
303 } // namespace clang
304 
305 namespace {
306 
307 class SingleFrontendActionFactory : public FrontendActionFactory {
308   std::unique_ptr<FrontendAction> Action;
309 
310 public:
311   SingleFrontendActionFactory(std::unique_ptr<FrontendAction> Action)
312       : Action(std::move(Action)) {}
313 
314   std::unique_ptr<FrontendAction> create() override {
315     return std::move(Action);
316   }
317 };
318 
319 } // namespace
320 
321 ToolInvocation::ToolInvocation(
322     std::vector<std::string> CommandLine, ToolAction *Action,
323     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
324     : CommandLine(std::move(CommandLine)), Action(Action), OwnsAction(false),
325       Files(Files), PCHContainerOps(std::move(PCHContainerOps)) {}
326 
327 ToolInvocation::ToolInvocation(
328     std::vector<std::string> CommandLine,
329     std::unique_ptr<FrontendAction> FAction, FileManager *Files,
330     std::shared_ptr<PCHContainerOperations> PCHContainerOps)
331     : CommandLine(std::move(CommandLine)),
332       Action(new SingleFrontendActionFactory(std::move(FAction))),
333       OwnsAction(true), Files(Files),
334       PCHContainerOps(std::move(PCHContainerOps)) {}
335 
336 ToolInvocation::~ToolInvocation() {
337   if (OwnsAction)
338     delete Action;
339 }
340 
341 bool ToolInvocation::run() {
342   llvm::opt::ArgStringList Argv;
343   for (const std::string &Str : CommandLine)
344     Argv.push_back(Str.c_str());
345   const char *const BinaryName = Argv[0];
346 
347   // Parse diagnostic options from the driver command-line only if none were
348   // explicitly set.
349   IntrusiveRefCntPtr<DiagnosticOptions> ParsedDiagOpts;
350   DiagnosticOptions *DiagOpts = this->DiagOpts;
351   if (!DiagOpts) {
352     ParsedDiagOpts = CreateAndPopulateDiagOpts(Argv);
353     DiagOpts = &*ParsedDiagOpts;
354   }
355 
356   TextDiagnosticPrinter DiagnosticPrinter(llvm::errs(), DiagOpts);
357   IntrusiveRefCntPtr<DiagnosticsEngine> Diagnostics =
358       CompilerInstance::createDiagnostics(
359           &*DiagOpts, DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
360   // Although `Diagnostics` are used only for command-line parsing, the custom
361   // `DiagConsumer` might expect a `SourceManager` to be present.
362   SourceManager SrcMgr(*Diagnostics, *Files);
363   Diagnostics->setSourceManager(&SrcMgr);
364 
365   // We already have a cc1, just create an invocation.
366   if (CommandLine.size() >= 2 && CommandLine[1] == "-cc1") {
367     ArrayRef<const char *> CC1Args = ArrayRef(Argv).drop_front();
368     std::unique_ptr<CompilerInvocation> Invocation(
369         newInvocation(&*Diagnostics, CC1Args, BinaryName));
370     if (Diagnostics->hasErrorOccurred())
371       return false;
372     return Action->runInvocation(std::move(Invocation), Files,
373                                  std::move(PCHContainerOps), DiagConsumer);
374   }
375 
376   const std::unique_ptr<driver::Driver> Driver(
377       newDriver(&*Diagnostics, BinaryName, &Files->getVirtualFileSystem()));
378   // The "input file not found" diagnostics from the driver are useful.
379   // The driver is only aware of the VFS working directory, but some clients
380   // change this at the FileManager level instead.
381   // In this case the checks have false positives, so skip them.
382   if (!Files->getFileSystemOpts().WorkingDir.empty())
383     Driver->setCheckInputsExist(false);
384   const std::unique_ptr<driver::Compilation> Compilation(
385       Driver->BuildCompilation(llvm::ArrayRef(Argv)));
386   if (!Compilation)
387     return false;
388   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
389       &*Diagnostics, Compilation.get());
390   if (!CC1Args)
391     return false;
392   std::unique_ptr<CompilerInvocation> Invocation(
393       newInvocation(&*Diagnostics, *CC1Args, BinaryName));
394   return runInvocation(BinaryName, Compilation.get(), std::move(Invocation),
395                        std::move(PCHContainerOps));
396 }
397 
398 bool ToolInvocation::runInvocation(
399     const char *BinaryName, driver::Compilation *Compilation,
400     std::shared_ptr<CompilerInvocation> Invocation,
401     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
402   // Show the invocation, with -v.
403   if (Invocation->getHeaderSearchOpts().Verbose) {
404     llvm::errs() << "clang Invocation:\n";
405     Compilation->getJobs().Print(llvm::errs(), "\n", true);
406     llvm::errs() << "\n";
407   }
408 
409   return Action->runInvocation(std::move(Invocation), Files,
410                                std::move(PCHContainerOps), DiagConsumer);
411 }
412 
413 bool FrontendActionFactory::runInvocation(
414     std::shared_ptr<CompilerInvocation> Invocation, FileManager *Files,
415     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
416     DiagnosticConsumer *DiagConsumer) {
417   // Create a compiler instance to handle the actual work.
418   CompilerInstance Compiler(std::move(PCHContainerOps));
419   Compiler.setInvocation(std::move(Invocation));
420   Compiler.setFileManager(Files);
421 
422   // The FrontendAction can have lifetime requirements for Compiler or its
423   // members, and we need to ensure it's deleted earlier than Compiler. So we
424   // pass it to an std::unique_ptr declared after the Compiler variable.
425   std::unique_ptr<FrontendAction> ScopedToolAction(create());
426 
427   // Create the compiler's actual diagnostics engine.
428   Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
429   if (!Compiler.hasDiagnostics())
430     return false;
431 
432   Compiler.createSourceManager(*Files);
433 
434   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
435 
436   Files->clearStatCache();
437   return Success;
438 }
439 
440 ClangTool::ClangTool(const CompilationDatabase &Compilations,
441                      ArrayRef<std::string> SourcePaths,
442                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
443                      IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
444                      IntrusiveRefCntPtr<FileManager> Files)
445     : Compilations(Compilations), SourcePaths(SourcePaths),
446       PCHContainerOps(std::move(PCHContainerOps)),
447       OverlayFileSystem(new llvm::vfs::OverlayFileSystem(std::move(BaseFS))),
448       InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
449       Files(Files ? Files
450                   : new FileManager(FileSystemOptions(), OverlayFileSystem)) {
451   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
452   appendArgumentsAdjuster(getClangStripOutputAdjuster());
453   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
454   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
455   if (Files)
456     Files->setVirtualFileSystem(OverlayFileSystem);
457 }
458 
459 ClangTool::~ClangTool() = default;
460 
461 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
462   MappedFileContents.push_back(std::make_pair(FilePath, Content));
463 }
464 
465 void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
466   ArgsAdjuster = combineAdjusters(std::move(ArgsAdjuster), std::move(Adjuster));
467 }
468 
469 void ClangTool::clearArgumentsAdjusters() {
470   ArgsAdjuster = nullptr;
471 }
472 
473 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
474                               void *MainAddr) {
475   // Allow users to override the resource dir.
476   for (StringRef Arg : Args)
477     if (Arg.startswith("-resource-dir"))
478       return;
479 
480   // If there's no override in place add our resource dir.
481   Args = getInsertArgumentAdjuster(
482       ("-resource-dir=" + CompilerInvocation::GetResourcesPath(Argv0, MainAddr))
483           .c_str())(Args, "");
484 }
485 
486 int ClangTool::run(ToolAction *Action) {
487   // Exists solely for the purpose of lookup of the resource path.
488   // This just needs to be some symbol in the binary.
489   static int StaticSymbol;
490 
491   // First insert all absolute paths into the in-memory VFS. These are global
492   // for all compile commands.
493   if (SeenWorkingDirectories.insert("/").second)
494     for (const auto &MappedFile : MappedFileContents)
495       if (llvm::sys::path::is_absolute(MappedFile.first))
496         InMemoryFileSystem->addFile(
497             MappedFile.first, 0,
498             llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
499 
500   bool ProcessingFailed = false;
501   bool FileSkipped = false;
502   // Compute all absolute paths before we run any actions, as those will change
503   // the working directory.
504   std::vector<std::string> AbsolutePaths;
505   AbsolutePaths.reserve(SourcePaths.size());
506   for (const auto &SourcePath : SourcePaths) {
507     auto AbsPath = getAbsolutePath(*OverlayFileSystem, SourcePath);
508     if (!AbsPath) {
509       llvm::errs() << "Skipping " << SourcePath
510                    << ". Error while getting an absolute path: "
511                    << llvm::toString(AbsPath.takeError()) << "\n";
512       continue;
513     }
514     AbsolutePaths.push_back(std::move(*AbsPath));
515   }
516 
517   // Remember the working directory in case we need to restore it.
518   std::string InitialWorkingDir;
519   if (RestoreCWD) {
520     if (auto CWD = OverlayFileSystem->getCurrentWorkingDirectory()) {
521       InitialWorkingDir = std::move(*CWD);
522     } else {
523       llvm::errs() << "Could not get working directory: "
524                    << CWD.getError().message() << "\n";
525     }
526   }
527 
528   for (llvm::StringRef File : AbsolutePaths) {
529     // Currently implementations of CompilationDatabase::getCompileCommands can
530     // change the state of the file system (e.g.  prepare generated headers), so
531     // this method needs to run right before we invoke the tool, as the next
532     // file may require a different (incompatible) state of the file system.
533     //
534     // FIXME: Make the compilation database interface more explicit about the
535     // requirements to the order of invocation of its members.
536     std::vector<CompileCommand> CompileCommandsForFile =
537         Compilations.getCompileCommands(File);
538     if (CompileCommandsForFile.empty()) {
539       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
540       FileSkipped = true;
541       continue;
542     }
543     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
544       // FIXME: chdir is thread hostile; on the other hand, creating the same
545       // behavior as chdir is complex: chdir resolves the path once, thus
546       // guaranteeing that all subsequent relative path operations work
547       // on the same path the original chdir resulted in. This makes a
548       // difference for example on network filesystems, where symlinks might be
549       // switched during runtime of the tool. Fixing this depends on having a
550       // file system abstraction that allows openat() style interactions.
551       if (OverlayFileSystem->setCurrentWorkingDirectory(
552               CompileCommand.Directory))
553         llvm::report_fatal_error("Cannot chdir into \"" +
554                                  Twine(CompileCommand.Directory) + "\"!");
555 
556       // Now fill the in-memory VFS with the relative file mappings so it will
557       // have the correct relative paths. We never remove mappings but that
558       // should be fine.
559       if (SeenWorkingDirectories.insert(CompileCommand.Directory).second)
560         for (const auto &MappedFile : MappedFileContents)
561           if (!llvm::sys::path::is_absolute(MappedFile.first))
562             InMemoryFileSystem->addFile(
563                 MappedFile.first, 0,
564                 llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
565 
566       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
567       if (ArgsAdjuster)
568         CommandLine = ArgsAdjuster(CommandLine, CompileCommand.Filename);
569       assert(!CommandLine.empty());
570 
571       // Add the resource dir based on the binary of this tool. argv[0] in the
572       // compilation database may refer to a different compiler and we want to
573       // pick up the very same standard library that compiler is using. The
574       // builtin headers in the resource dir need to match the exact clang
575       // version the tool is using.
576       // FIXME: On linux, GetMainExecutable is independent of the value of the
577       // first argument, thus allowing ClangTool and runToolOnCode to just
578       // pass in made-up names here. Make sure this works on other platforms.
579       injectResourceDir(CommandLine, "clang_tool", &StaticSymbol);
580 
581       // FIXME: We need a callback mechanism for the tool writer to output a
582       // customized message for each file.
583       LLVM_DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
584       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
585                                 PCHContainerOps);
586       Invocation.setDiagnosticConsumer(DiagConsumer);
587 
588       if (!Invocation.run()) {
589         // FIXME: Diagnostics should be used instead.
590         if (PrintErrorMessage)
591           llvm::errs() << "Error while processing " << File << ".\n";
592         ProcessingFailed = true;
593       }
594     }
595   }
596 
597   if (!InitialWorkingDir.empty()) {
598     if (auto EC =
599             OverlayFileSystem->setCurrentWorkingDirectory(InitialWorkingDir))
600       llvm::errs() << "Error when trying to restore working dir: "
601                    << EC.message() << "\n";
602   }
603   return ProcessingFailed ? 1 : (FileSkipped ? 2 : 0);
604 }
605 
606 namespace {
607 
608 class ASTBuilderAction : public ToolAction {
609   std::vector<std::unique_ptr<ASTUnit>> &ASTs;
610 
611 public:
612   ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}
613 
614   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
615                      FileManager *Files,
616                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
617                      DiagnosticConsumer *DiagConsumer) override {
618     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
619         Invocation, std::move(PCHContainerOps),
620         CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
621                                             DiagConsumer,
622                                             /*ShouldOwnClient=*/false),
623         Files);
624     if (!AST)
625       return false;
626 
627     ASTs.push_back(std::move(AST));
628     return true;
629   }
630 };
631 
632 } // namespace
633 
634 int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
635   ASTBuilderAction Action(ASTs);
636   return run(&Action);
637 }
638 
639 void ClangTool::setRestoreWorkingDir(bool RestoreCWD) {
640   this->RestoreCWD = RestoreCWD;
641 }
642 
643 void ClangTool::setPrintErrorMessage(bool PrintErrorMessage) {
644   this->PrintErrorMessage = PrintErrorMessage;
645 }
646 
647 namespace clang {
648 namespace tooling {
649 
650 std::unique_ptr<ASTUnit>
651 buildASTFromCode(StringRef Code, StringRef FileName,
652                  std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
653   return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName,
654                                   "clang-tool", std::move(PCHContainerOps));
655 }
656 
657 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
658     StringRef Code, const std::vector<std::string> &Args, StringRef FileName,
659     StringRef ToolName, std::shared_ptr<PCHContainerOperations> PCHContainerOps,
660     ArgumentsAdjuster Adjuster, const FileContentMappings &VirtualMappedFiles,
661     DiagnosticConsumer *DiagConsumer) {
662   std::vector<std::unique_ptr<ASTUnit>> ASTs;
663   ASTBuilderAction Action(ASTs);
664   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
665       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
666   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
667       new llvm::vfs::InMemoryFileSystem);
668   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
669   llvm::IntrusiveRefCntPtr<FileManager> Files(
670       new FileManager(FileSystemOptions(), OverlayFileSystem));
671 
672   ToolInvocation Invocation(
673       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileName), FileName),
674       &Action, Files.get(), std::move(PCHContainerOps));
675   Invocation.setDiagnosticConsumer(DiagConsumer);
676 
677   InMemoryFileSystem->addFile(FileName, 0,
678                               llvm::MemoryBuffer::getMemBufferCopy(Code));
679   for (auto &FilenameWithContent : VirtualMappedFiles) {
680     InMemoryFileSystem->addFile(
681         FilenameWithContent.first, 0,
682         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
683   }
684 
685   if (!Invocation.run())
686     return nullptr;
687 
688   assert(ASTs.size() == 1);
689   return std::move(ASTs[0]);
690 }
691 
692 } // namespace tooling
693 } // namespace clang
694