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/CommandLine.h"
47 #include "llvm/Support/Debug.h"
48 #include "llvm/Support/ErrorHandling.h"
49 #include "llvm/Support/FileSystem.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 "llvm/TargetParser/Host.h"
55 #include <cassert>
56 #include <cstring>
57 #include <memory>
58 #include <string>
59 #include <system_error>
60 #include <utility>
61 #include <vector>
62 
63 #define DEBUG_TYPE "clang-tooling"
64 
65 using namespace clang;
66 using namespace tooling;
67 
68 ToolAction::~ToolAction() = default;
69 
70 FrontendActionFactory::~FrontendActionFactory() = default;
71 
72 // FIXME: This file contains structural duplication with other parts of the
73 // code that sets up a compiler to run tools on it, and we should refactor
74 // it to be based on the same framework.
75 
76 /// Builds a clang driver initialized for running clang tools.
77 static driver::Driver *
78 newDriver(DiagnosticsEngine *Diagnostics, const char *BinaryName,
79           IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
80   driver::Driver *CompilerDriver =
81       new driver::Driver(BinaryName, llvm::sys::getDefaultTargetTriple(),
82                          *Diagnostics, "clang LLVM compiler", std::move(VFS));
83   CompilerDriver->setTitle("clang_based_tool");
84   return CompilerDriver;
85 }
86 
87 /// Decide whether extra compiler frontend commands can be ignored.
88 static bool ignoreExtraCC1Commands(const driver::Compilation *Compilation) {
89   const driver::JobList &Jobs = Compilation->getJobs();
90   const driver::ActionList &Actions = Compilation->getActions();
91 
92   bool OffloadCompilation = false;
93 
94   // Jobs and Actions look very different depending on whether the Clang tool
95   // injected -fsyntax-only or not. Try to handle both cases here.
96 
97   for (const auto &Job : Jobs)
98     if (StringRef(Job.getExecutable()) == "clang-offload-bundler")
99       OffloadCompilation = true;
100 
101   if (Jobs.size() > 1) {
102     for (auto *A : Actions){
103       // On MacOSX real actions may end up being wrapped in BindArchAction
104       if (isa<driver::BindArchAction>(A))
105         A = *A->input_begin();
106       if (isa<driver::OffloadAction>(A)) {
107         // Offload compilation has 2 top-level actions, one (at the front) is
108         // the original host compilation and the other is offload action
109         // composed of at least one device compilation. For such case, general
110         // tooling will consider host-compilation only. For tooling on device
111         // compilation, device compilation only option, such as
112         // `--cuda-device-only`, needs specifying.
113         assert(Actions.size() > 1);
114         assert(
115             isa<driver::CompileJobAction>(Actions.front()) ||
116             // On MacOSX real actions may end up being wrapped in
117             // BindArchAction.
118             (isa<driver::BindArchAction>(Actions.front()) &&
119              isa<driver::CompileJobAction>(*Actions.front()->input_begin())));
120         OffloadCompilation = true;
121         break;
122       }
123     }
124   }
125 
126   return OffloadCompilation;
127 }
128 
129 namespace clang {
130 namespace tooling {
131 
132 const llvm::opt::ArgStringList *
133 getCC1Arguments(DiagnosticsEngine *Diagnostics,
134                 driver::Compilation *Compilation) {
135   const driver::JobList &Jobs = Compilation->getJobs();
136 
137   auto IsCC1Command = [](const driver::Command &Cmd) {
138     return StringRef(Cmd.getCreator().getName()) == "clang";
139   };
140 
141   auto IsSrcFile = [](const driver::InputInfo &II) {
142     return isSrcFile(II.getType());
143   };
144 
145   llvm::SmallVector<const driver::Command *, 1> CC1Jobs;
146   for (const driver::Command &Job : Jobs)
147     if (IsCC1Command(Job) && llvm::all_of(Job.getInputInfos(), IsSrcFile))
148       CC1Jobs.push_back(&Job);
149 
150   // If there are no jobs for source files, try checking again for a single job
151   // with any file type. This accepts a preprocessed file as input.
152   if (CC1Jobs.empty())
153     for (const driver::Command &Job : Jobs)
154       if (IsCC1Command(Job))
155         CC1Jobs.push_back(&Job);
156 
157   if (CC1Jobs.empty() ||
158       (CC1Jobs.size() > 1 && !ignoreExtraCC1Commands(Compilation))) {
159     SmallString<256> error_msg;
160     llvm::raw_svector_ostream error_stream(error_msg);
161     Jobs.Print(error_stream, "; ", true);
162     Diagnostics->Report(diag::err_fe_expected_compiler_job)
163         << error_stream.str();
164     return nullptr;
165   }
166 
167   return &CC1Jobs[0]->getArguments();
168 }
169 
170 /// Returns a clang build invocation initialized from the CC1 flags.
171 CompilerInvocation *newInvocation(DiagnosticsEngine *Diagnostics,
172                                   ArrayRef<const char *> CC1Args,
173                                   const char *const BinaryName) {
174   assert(!CC1Args.empty() && "Must at least contain the program name!");
175   CompilerInvocation *Invocation = new CompilerInvocation;
176   CompilerInvocation::CreateFromArgs(*Invocation, CC1Args, *Diagnostics,
177                                      BinaryName);
178   Invocation->getFrontendOpts().DisableFree = false;
179   Invocation->getCodeGenOpts().DisableFree = false;
180   return Invocation;
181 }
182 
183 bool runToolOnCode(std::unique_ptr<FrontendAction> ToolAction,
184                    const Twine &Code, const Twine &FileName,
185                    std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
186   return runToolOnCodeWithArgs(std::move(ToolAction), Code,
187                                std::vector<std::string>(), FileName,
188                                "clang-tool", std::move(PCHContainerOps));
189 }
190 
191 } // namespace tooling
192 } // namespace clang
193 
194 static std::vector<std::string>
195 getSyntaxOnlyToolArgs(const Twine &ToolName,
196                       const std::vector<std::string> &ExtraArgs,
197                       StringRef FileName) {
198   std::vector<std::string> Args;
199   Args.push_back(ToolName.str());
200   Args.push_back("-fsyntax-only");
201   Args.insert(Args.end(), ExtraArgs.begin(), ExtraArgs.end());
202   Args.push_back(FileName.str());
203   return Args;
204 }
205 
206 namespace clang {
207 namespace tooling {
208 
209 bool runToolOnCodeWithArgs(
210     std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
211     llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
212     const std::vector<std::string> &Args, const Twine &FileName,
213     const Twine &ToolName,
214     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
215   SmallString<16> FileNameStorage;
216   StringRef FileNameRef = FileName.toNullTerminatedStringRef(FileNameStorage);
217 
218   llvm::IntrusiveRefCntPtr<FileManager> Files(
219       new FileManager(FileSystemOptions(), VFS));
220   ArgumentsAdjuster Adjuster = getClangStripDependencyFileAdjuster();
221   ToolInvocation Invocation(
222       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileNameRef), FileNameRef),
223       std::move(ToolAction), Files.get(), std::move(PCHContainerOps));
224   return Invocation.run();
225 }
226 
227 bool runToolOnCodeWithArgs(
228     std::unique_ptr<FrontendAction> ToolAction, const Twine &Code,
229     const std::vector<std::string> &Args, const Twine &FileName,
230     const Twine &ToolName,
231     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
232     const FileContentMappings &VirtualMappedFiles) {
233   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
234       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
235   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
236       new llvm::vfs::InMemoryFileSystem);
237   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
238 
239   SmallString<1024> CodeStorage;
240   InMemoryFileSystem->addFile(FileName, 0,
241                               llvm::MemoryBuffer::getMemBuffer(
242                                   Code.toNullTerminatedStringRef(CodeStorage)));
243 
244   for (auto &FilenameWithContent : VirtualMappedFiles) {
245     InMemoryFileSystem->addFile(
246         FilenameWithContent.first, 0,
247         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
248   }
249 
250   return runToolOnCodeWithArgs(std::move(ToolAction), Code, OverlayFileSystem,
251                                Args, FileName, ToolName);
252 }
253 
254 llvm::Expected<std::string> getAbsolutePath(llvm::vfs::FileSystem &FS,
255                                             StringRef File) {
256   StringRef RelativePath(File);
257   // FIXME: Should '.\\' be accepted on Win32?
258   if (RelativePath.starts_with("./")) {
259     RelativePath = RelativePath.substr(strlen("./"));
260   }
261 
262   SmallString<1024> AbsolutePath = RelativePath;
263   if (auto EC = FS.makeAbsolute(AbsolutePath))
264     return llvm::errorCodeToError(EC);
265   llvm::sys::path::native(AbsolutePath);
266   return std::string(AbsolutePath.str());
267 }
268 
269 std::string getAbsolutePath(StringRef File) {
270   return llvm::cantFail(getAbsolutePath(*llvm::vfs::getRealFileSystem(), File));
271 }
272 
273 void addTargetAndModeForProgramName(std::vector<std::string> &CommandLine,
274                                     StringRef InvokedAs) {
275   if (CommandLine.empty() || InvokedAs.empty())
276     return;
277   const auto &Table = driver::getDriverOptTable();
278   // --target=X
279   StringRef TargetOPT =
280       Table.getOption(driver::options::OPT_target).getPrefixedName();
281   // -target X
282   StringRef TargetOPTLegacy =
283       Table.getOption(driver::options::OPT_target_legacy_spelling)
284           .getPrefixedName();
285   // --driver-mode=X
286   StringRef DriverModeOPT =
287       Table.getOption(driver::options::OPT_driver_mode).getPrefixedName();
288   auto TargetMode =
289       driver::ToolChain::getTargetAndModeFromProgramName(InvokedAs);
290   // No need to search for target args if we don't have a target/mode to insert.
291   bool ShouldAddTarget = TargetMode.TargetIsValid;
292   bool ShouldAddMode = TargetMode.DriverMode != nullptr;
293   // Skip CommandLine[0].
294   for (auto Token = ++CommandLine.begin(); Token != CommandLine.end();
295        ++Token) {
296     StringRef TokenRef(*Token);
297     ShouldAddTarget = ShouldAddTarget && !TokenRef.starts_with(TargetOPT) &&
298                       !TokenRef.equals(TargetOPTLegacy);
299     ShouldAddMode = ShouldAddMode && !TokenRef.starts_with(DriverModeOPT);
300   }
301   if (ShouldAddMode) {
302     CommandLine.insert(++CommandLine.begin(), TargetMode.DriverMode);
303   }
304   if (ShouldAddTarget) {
305     CommandLine.insert(++CommandLine.begin(),
306                        (TargetOPT + TargetMode.TargetPrefix).str());
307   }
308 }
309 
310 void addExpandedResponseFiles(std::vector<std::string> &CommandLine,
311                               llvm::StringRef WorkingDir,
312                               llvm::cl::TokenizerCallback Tokenizer,
313                               llvm::vfs::FileSystem &FS) {
314   bool SeenRSPFile = false;
315   llvm::SmallVector<const char *, 20> Argv;
316   Argv.reserve(CommandLine.size());
317   for (auto &Arg : CommandLine) {
318     Argv.push_back(Arg.c_str());
319     if (!Arg.empty())
320       SeenRSPFile |= Arg.front() == '@';
321   }
322   if (!SeenRSPFile)
323     return;
324   llvm::BumpPtrAllocator Alloc;
325   llvm::cl::ExpansionContext ECtx(Alloc, Tokenizer);
326   llvm::Error Err =
327       ECtx.setVFS(&FS).setCurrentDir(WorkingDir).expandResponseFiles(Argv);
328   if (Err)
329     llvm::errs() << Err;
330   // Don't assign directly, Argv aliases CommandLine.
331   std::vector<std::string> ExpandedArgv(Argv.begin(), Argv.end());
332   CommandLine = std::move(ExpandedArgv);
333 }
334 
335 } // namespace tooling
336 } // namespace clang
337 
338 namespace {
339 
340 class SingleFrontendActionFactory : public FrontendActionFactory {
341   std::unique_ptr<FrontendAction> Action;
342 
343 public:
344   SingleFrontendActionFactory(std::unique_ptr<FrontendAction> Action)
345       : Action(std::move(Action)) {}
346 
347   std::unique_ptr<FrontendAction> create() override {
348     return std::move(Action);
349   }
350 };
351 
352 } // namespace
353 
354 ToolInvocation::ToolInvocation(
355     std::vector<std::string> CommandLine, ToolAction *Action,
356     FileManager *Files, std::shared_ptr<PCHContainerOperations> PCHContainerOps)
357     : CommandLine(std::move(CommandLine)), Action(Action), OwnsAction(false),
358       Files(Files), PCHContainerOps(std::move(PCHContainerOps)) {}
359 
360 ToolInvocation::ToolInvocation(
361     std::vector<std::string> CommandLine,
362     std::unique_ptr<FrontendAction> FAction, FileManager *Files,
363     std::shared_ptr<PCHContainerOperations> PCHContainerOps)
364     : CommandLine(std::move(CommandLine)),
365       Action(new SingleFrontendActionFactory(std::move(FAction))),
366       OwnsAction(true), Files(Files),
367       PCHContainerOps(std::move(PCHContainerOps)) {}
368 
369 ToolInvocation::~ToolInvocation() {
370   if (OwnsAction)
371     delete Action;
372 }
373 
374 bool ToolInvocation::run() {
375   llvm::opt::ArgStringList Argv;
376   for (const std::string &Str : CommandLine)
377     Argv.push_back(Str.c_str());
378   const char *const BinaryName = Argv[0];
379 
380   // Parse diagnostic options from the driver command-line only if none were
381   // explicitly set.
382   IntrusiveRefCntPtr<DiagnosticOptions> ParsedDiagOpts;
383   DiagnosticOptions *DiagOpts = this->DiagOpts;
384   if (!DiagOpts) {
385     ParsedDiagOpts = CreateAndPopulateDiagOpts(Argv);
386     DiagOpts = &*ParsedDiagOpts;
387   }
388 
389   TextDiagnosticPrinter DiagnosticPrinter(llvm::errs(), DiagOpts);
390   IntrusiveRefCntPtr<DiagnosticsEngine> Diagnostics =
391       CompilerInstance::createDiagnostics(
392           &*DiagOpts, DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
393   // Although `Diagnostics` are used only for command-line parsing, the custom
394   // `DiagConsumer` might expect a `SourceManager` to be present.
395   SourceManager SrcMgr(*Diagnostics, *Files);
396   Diagnostics->setSourceManager(&SrcMgr);
397 
398   // We already have a cc1, just create an invocation.
399   if (CommandLine.size() >= 2 && CommandLine[1] == "-cc1") {
400     ArrayRef<const char *> CC1Args = ArrayRef(Argv).drop_front();
401     std::unique_ptr<CompilerInvocation> Invocation(
402         newInvocation(&*Diagnostics, CC1Args, BinaryName));
403     if (Diagnostics->hasErrorOccurred())
404       return false;
405     return Action->runInvocation(std::move(Invocation), Files,
406                                  std::move(PCHContainerOps), DiagConsumer);
407   }
408 
409   const std::unique_ptr<driver::Driver> Driver(
410       newDriver(&*Diagnostics, BinaryName, &Files->getVirtualFileSystem()));
411   // The "input file not found" diagnostics from the driver are useful.
412   // The driver is only aware of the VFS working directory, but some clients
413   // change this at the FileManager level instead.
414   // In this case the checks have false positives, so skip them.
415   if (!Files->getFileSystemOpts().WorkingDir.empty())
416     Driver->setCheckInputsExist(false);
417   const std::unique_ptr<driver::Compilation> Compilation(
418       Driver->BuildCompilation(llvm::ArrayRef(Argv)));
419   if (!Compilation)
420     return false;
421   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
422       &*Diagnostics, Compilation.get());
423   if (!CC1Args)
424     return false;
425   std::unique_ptr<CompilerInvocation> Invocation(
426       newInvocation(&*Diagnostics, *CC1Args, BinaryName));
427   return runInvocation(BinaryName, Compilation.get(), std::move(Invocation),
428                        std::move(PCHContainerOps));
429 }
430 
431 bool ToolInvocation::runInvocation(
432     const char *BinaryName, driver::Compilation *Compilation,
433     std::shared_ptr<CompilerInvocation> Invocation,
434     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
435   // Show the invocation, with -v.
436   if (Invocation->getHeaderSearchOpts().Verbose) {
437     llvm::errs() << "clang Invocation:\n";
438     Compilation->getJobs().Print(llvm::errs(), "\n", true);
439     llvm::errs() << "\n";
440   }
441 
442   return Action->runInvocation(std::move(Invocation), Files,
443                                std::move(PCHContainerOps), DiagConsumer);
444 }
445 
446 bool FrontendActionFactory::runInvocation(
447     std::shared_ptr<CompilerInvocation> Invocation, FileManager *Files,
448     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
449     DiagnosticConsumer *DiagConsumer) {
450   // Create a compiler instance to handle the actual work.
451   CompilerInstance Compiler(std::move(PCHContainerOps));
452   Compiler.setInvocation(std::move(Invocation));
453   Compiler.setFileManager(Files);
454 
455   // The FrontendAction can have lifetime requirements for Compiler or its
456   // members, and we need to ensure it's deleted earlier than Compiler. So we
457   // pass it to an std::unique_ptr declared after the Compiler variable.
458   std::unique_ptr<FrontendAction> ScopedToolAction(create());
459 
460   // Create the compiler's actual diagnostics engine.
461   Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
462   if (!Compiler.hasDiagnostics())
463     return false;
464 
465   Compiler.createSourceManager(*Files);
466 
467   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
468 
469   Files->clearStatCache();
470   return Success;
471 }
472 
473 ClangTool::ClangTool(const CompilationDatabase &Compilations,
474                      ArrayRef<std::string> SourcePaths,
475                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
476                      IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
477                      IntrusiveRefCntPtr<FileManager> Files)
478     : Compilations(Compilations), SourcePaths(SourcePaths),
479       PCHContainerOps(std::move(PCHContainerOps)),
480       OverlayFileSystem(new llvm::vfs::OverlayFileSystem(std::move(BaseFS))),
481       InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
482       Files(Files ? Files
483                   : new FileManager(FileSystemOptions(), OverlayFileSystem)) {
484   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
485   appendArgumentsAdjuster(getClangStripOutputAdjuster());
486   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
487   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
488   if (Files)
489     Files->setVirtualFileSystem(OverlayFileSystem);
490 }
491 
492 ClangTool::~ClangTool() = default;
493 
494 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
495   MappedFileContents.push_back(std::make_pair(FilePath, Content));
496 }
497 
498 void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
499   ArgsAdjuster = combineAdjusters(std::move(ArgsAdjuster), std::move(Adjuster));
500 }
501 
502 void ClangTool::clearArgumentsAdjusters() {
503   ArgsAdjuster = nullptr;
504 }
505 
506 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
507                               void *MainAddr) {
508   // Allow users to override the resource dir.
509   for (StringRef Arg : Args)
510     if (Arg.starts_with("-resource-dir"))
511       return;
512 
513   // If there's no override in place add our resource dir.
514   Args = getInsertArgumentAdjuster(
515       ("-resource-dir=" + CompilerInvocation::GetResourcesPath(Argv0, MainAddr))
516           .c_str())(Args, "");
517 }
518 
519 int ClangTool::run(ToolAction *Action) {
520   // Exists solely for the purpose of lookup of the resource path.
521   // This just needs to be some symbol in the binary.
522   static int StaticSymbol;
523 
524   // First insert all absolute paths into the in-memory VFS. These are global
525   // for all compile commands.
526   if (SeenWorkingDirectories.insert("/").second)
527     for (const auto &MappedFile : MappedFileContents)
528       if (llvm::sys::path::is_absolute(MappedFile.first))
529         InMemoryFileSystem->addFile(
530             MappedFile.first, 0,
531             llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
532 
533   bool ProcessingFailed = false;
534   bool FileSkipped = false;
535   // Compute all absolute paths before we run any actions, as those will change
536   // the working directory.
537   std::vector<std::string> AbsolutePaths;
538   AbsolutePaths.reserve(SourcePaths.size());
539   for (const auto &SourcePath : SourcePaths) {
540     auto AbsPath = getAbsolutePath(*OverlayFileSystem, SourcePath);
541     if (!AbsPath) {
542       llvm::errs() << "Skipping " << SourcePath
543                    << ". Error while getting an absolute path: "
544                    << llvm::toString(AbsPath.takeError()) << "\n";
545       continue;
546     }
547     AbsolutePaths.push_back(std::move(*AbsPath));
548   }
549 
550   // Remember the working directory in case we need to restore it.
551   std::string InitialWorkingDir;
552   if (auto CWD = OverlayFileSystem->getCurrentWorkingDirectory()) {
553     InitialWorkingDir = std::move(*CWD);
554   } else {
555     llvm::errs() << "Could not get working directory: "
556                  << CWD.getError().message() << "\n";
557   }
558 
559   for (llvm::StringRef File : AbsolutePaths) {
560     // Currently implementations of CompilationDatabase::getCompileCommands can
561     // change the state of the file system (e.g.  prepare generated headers), so
562     // this method needs to run right before we invoke the tool, as the next
563     // file may require a different (incompatible) state of the file system.
564     //
565     // FIXME: Make the compilation database interface more explicit about the
566     // requirements to the order of invocation of its members.
567     std::vector<CompileCommand> CompileCommandsForFile =
568         Compilations.getCompileCommands(File);
569     if (CompileCommandsForFile.empty()) {
570       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
571       FileSkipped = true;
572       continue;
573     }
574     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
575       // FIXME: chdir is thread hostile; on the other hand, creating the same
576       // behavior as chdir is complex: chdir resolves the path once, thus
577       // guaranteeing that all subsequent relative path operations work
578       // on the same path the original chdir resulted in. This makes a
579       // difference for example on network filesystems, where symlinks might be
580       // switched during runtime of the tool. Fixing this depends on having a
581       // file system abstraction that allows openat() style interactions.
582       if (OverlayFileSystem->setCurrentWorkingDirectory(
583               CompileCommand.Directory))
584         llvm::report_fatal_error("Cannot chdir into \"" +
585                                  Twine(CompileCommand.Directory) + "\"!");
586 
587       // Now fill the in-memory VFS with the relative file mappings so it will
588       // have the correct relative paths. We never remove mappings but that
589       // should be fine.
590       if (SeenWorkingDirectories.insert(CompileCommand.Directory).second)
591         for (const auto &MappedFile : MappedFileContents)
592           if (!llvm::sys::path::is_absolute(MappedFile.first))
593             InMemoryFileSystem->addFile(
594                 MappedFile.first, 0,
595                 llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
596 
597       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
598       if (ArgsAdjuster)
599         CommandLine = ArgsAdjuster(CommandLine, CompileCommand.Filename);
600       assert(!CommandLine.empty());
601 
602       // Add the resource dir based on the binary of this tool. argv[0] in the
603       // compilation database may refer to a different compiler and we want to
604       // pick up the very same standard library that compiler is using. The
605       // builtin headers in the resource dir need to match the exact clang
606       // version the tool is using.
607       // FIXME: On linux, GetMainExecutable is independent of the value of the
608       // first argument, thus allowing ClangTool and runToolOnCode to just
609       // pass in made-up names here. Make sure this works on other platforms.
610       injectResourceDir(CommandLine, "clang_tool", &StaticSymbol);
611 
612       // FIXME: We need a callback mechanism for the tool writer to output a
613       // customized message for each file.
614       LLVM_DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
615       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
616                                 PCHContainerOps);
617       Invocation.setDiagnosticConsumer(DiagConsumer);
618 
619       if (!Invocation.run()) {
620         // FIXME: Diagnostics should be used instead.
621         if (PrintErrorMessage)
622           llvm::errs() << "Error while processing " << File << ".\n";
623         ProcessingFailed = true;
624       }
625     }
626   }
627 
628   if (!InitialWorkingDir.empty()) {
629     if (auto EC =
630             OverlayFileSystem->setCurrentWorkingDirectory(InitialWorkingDir))
631       llvm::errs() << "Error when trying to restore working dir: "
632                    << EC.message() << "\n";
633   }
634   return ProcessingFailed ? 1 : (FileSkipped ? 2 : 0);
635 }
636 
637 namespace {
638 
639 class ASTBuilderAction : public ToolAction {
640   std::vector<std::unique_ptr<ASTUnit>> &ASTs;
641 
642 public:
643   ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}
644 
645   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
646                      FileManager *Files,
647                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
648                      DiagnosticConsumer *DiagConsumer) override {
649     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
650         Invocation, std::move(PCHContainerOps),
651         CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
652                                             DiagConsumer,
653                                             /*ShouldOwnClient=*/false),
654         Files);
655     if (!AST)
656       return false;
657 
658     ASTs.push_back(std::move(AST));
659     return true;
660   }
661 };
662 
663 } // namespace
664 
665 int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
666   ASTBuilderAction Action(ASTs);
667   return run(&Action);
668 }
669 
670 void ClangTool::setPrintErrorMessage(bool PrintErrorMessage) {
671   this->PrintErrorMessage = PrintErrorMessage;
672 }
673 
674 namespace clang {
675 namespace tooling {
676 
677 std::unique_ptr<ASTUnit>
678 buildASTFromCode(StringRef Code, StringRef FileName,
679                  std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
680   return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName,
681                                   "clang-tool", std::move(PCHContainerOps));
682 }
683 
684 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
685     StringRef Code, const std::vector<std::string> &Args, StringRef FileName,
686     StringRef ToolName, std::shared_ptr<PCHContainerOperations> PCHContainerOps,
687     ArgumentsAdjuster Adjuster, const FileContentMappings &VirtualMappedFiles,
688     DiagnosticConsumer *DiagConsumer) {
689   std::vector<std::unique_ptr<ASTUnit>> ASTs;
690   ASTBuilderAction Action(ASTs);
691   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
692       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
693   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
694       new llvm::vfs::InMemoryFileSystem);
695   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
696   llvm::IntrusiveRefCntPtr<FileManager> Files(
697       new FileManager(FileSystemOptions(), OverlayFileSystem));
698 
699   ToolInvocation Invocation(
700       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileName), FileName),
701       &Action, Files.get(), std::move(PCHContainerOps));
702   Invocation.setDiagnosticConsumer(DiagConsumer);
703 
704   InMemoryFileSystem->addFile(FileName, 0,
705                               llvm::MemoryBuffer::getMemBufferCopy(Code));
706   for (auto &FilenameWithContent : VirtualMappedFiles) {
707     InMemoryFileSystem->addFile(
708         FilenameWithContent.first, 0,
709         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
710   }
711 
712   if (!Invocation.run())
713     return nullptr;
714 
715   assert(ASTs.size() == 1);
716   return std::move(ASTs[0]);
717 }
718 
719 } // namespace tooling
720 } // namespace clang
721