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                                   const llvm::opt::ArgStringList &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   std::vector<const char*> Argv;
343   for (const std::string &Str : CommandLine)
344     Argv.push_back(Str.c_str());
345   const char *const BinaryName = Argv[0];
346   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
347   unsigned MissingArgIndex, MissingArgCount;
348   llvm::opt::InputArgList ParsedArgs = driver::getDriverOptTable().ParseArgs(
349       ArrayRef<const char *>(Argv).slice(1), MissingArgIndex, MissingArgCount);
350   ParseDiagnosticArgs(*DiagOpts, ParsedArgs);
351   TextDiagnosticPrinter DiagnosticPrinter(
352       llvm::errs(), &*DiagOpts);
353   DiagnosticsEngine Diagnostics(
354       IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
355       DiagConsumer ? DiagConsumer : &DiagnosticPrinter, false);
356   // Although `Diagnostics` are used only for command-line parsing, the custom
357   // `DiagConsumer` might expect a `SourceManager` to be present.
358   SourceManager SrcMgr(Diagnostics, *Files);
359   Diagnostics.setSourceManager(&SrcMgr);
360 
361   const std::unique_ptr<driver::Driver> Driver(
362       newDriver(&Diagnostics, BinaryName, &Files->getVirtualFileSystem()));
363   // The "input file not found" diagnostics from the driver are useful.
364   // The driver is only aware of the VFS working directory, but some clients
365   // change this at the FileManager level instead.
366   // In this case the checks have false positives, so skip them.
367   if (!Files->getFileSystemOpts().WorkingDir.empty())
368     Driver->setCheckInputsExist(false);
369   const std::unique_ptr<driver::Compilation> Compilation(
370       Driver->BuildCompilation(llvm::makeArrayRef(Argv)));
371   if (!Compilation)
372     return false;
373   const llvm::opt::ArgStringList *const CC1Args = getCC1Arguments(
374       &Diagnostics, Compilation.get());
375   if (!CC1Args)
376     return false;
377   std::unique_ptr<CompilerInvocation> Invocation(
378       newInvocation(&Diagnostics, *CC1Args, BinaryName));
379   return runInvocation(BinaryName, Compilation.get(), std::move(Invocation),
380                        std::move(PCHContainerOps));
381 }
382 
383 bool ToolInvocation::runInvocation(
384     const char *BinaryName, driver::Compilation *Compilation,
385     std::shared_ptr<CompilerInvocation> Invocation,
386     std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
387   // Show the invocation, with -v.
388   if (Invocation->getHeaderSearchOpts().Verbose) {
389     llvm::errs() << "clang Invocation:\n";
390     Compilation->getJobs().Print(llvm::errs(), "\n", true);
391     llvm::errs() << "\n";
392   }
393 
394   return Action->runInvocation(std::move(Invocation), Files,
395                                std::move(PCHContainerOps), DiagConsumer);
396 }
397 
398 bool FrontendActionFactory::runInvocation(
399     std::shared_ptr<CompilerInvocation> Invocation, FileManager *Files,
400     std::shared_ptr<PCHContainerOperations> PCHContainerOps,
401     DiagnosticConsumer *DiagConsumer) {
402   // Create a compiler instance to handle the actual work.
403   CompilerInstance Compiler(std::move(PCHContainerOps));
404   Compiler.setInvocation(std::move(Invocation));
405   Compiler.setFileManager(Files);
406 
407   // The FrontendAction can have lifetime requirements for Compiler or its
408   // members, and we need to ensure it's deleted earlier than Compiler. So we
409   // pass it to an std::unique_ptr declared after the Compiler variable.
410   std::unique_ptr<FrontendAction> ScopedToolAction(create());
411 
412   // Create the compiler's actual diagnostics engine.
413   Compiler.createDiagnostics(DiagConsumer, /*ShouldOwnClient=*/false);
414   if (!Compiler.hasDiagnostics())
415     return false;
416 
417   Compiler.createSourceManager(*Files);
418 
419   const bool Success = Compiler.ExecuteAction(*ScopedToolAction);
420 
421   Files->clearStatCache();
422   return Success;
423 }
424 
425 ClangTool::ClangTool(const CompilationDatabase &Compilations,
426                      ArrayRef<std::string> SourcePaths,
427                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
428                      IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS,
429                      IntrusiveRefCntPtr<FileManager> Files)
430     : Compilations(Compilations), SourcePaths(SourcePaths),
431       PCHContainerOps(std::move(PCHContainerOps)),
432       OverlayFileSystem(new llvm::vfs::OverlayFileSystem(std::move(BaseFS))),
433       InMemoryFileSystem(new llvm::vfs::InMemoryFileSystem),
434       Files(Files ? Files
435                   : new FileManager(FileSystemOptions(), OverlayFileSystem)) {
436   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
437   appendArgumentsAdjuster(getClangStripOutputAdjuster());
438   appendArgumentsAdjuster(getClangSyntaxOnlyAdjuster());
439   appendArgumentsAdjuster(getClangStripDependencyFileAdjuster());
440   if (Files)
441     Files->setVirtualFileSystem(OverlayFileSystem);
442 }
443 
444 ClangTool::~ClangTool() = default;
445 
446 void ClangTool::mapVirtualFile(StringRef FilePath, StringRef Content) {
447   MappedFileContents.push_back(std::make_pair(FilePath, Content));
448 }
449 
450 void ClangTool::appendArgumentsAdjuster(ArgumentsAdjuster Adjuster) {
451   ArgsAdjuster = combineAdjusters(std::move(ArgsAdjuster), std::move(Adjuster));
452 }
453 
454 void ClangTool::clearArgumentsAdjusters() {
455   ArgsAdjuster = nullptr;
456 }
457 
458 static void injectResourceDir(CommandLineArguments &Args, const char *Argv0,
459                               void *MainAddr) {
460   // Allow users to override the resource dir.
461   for (StringRef Arg : Args)
462     if (Arg.startswith("-resource-dir"))
463       return;
464 
465   // If there's no override in place add our resource dir.
466   Args = getInsertArgumentAdjuster(
467       ("-resource-dir=" + CompilerInvocation::GetResourcesPath(Argv0, MainAddr))
468           .c_str())(Args, "");
469 }
470 
471 int ClangTool::run(ToolAction *Action) {
472   // Exists solely for the purpose of lookup of the resource path.
473   // This just needs to be some symbol in the binary.
474   static int StaticSymbol;
475 
476   // First insert all absolute paths into the in-memory VFS. These are global
477   // for all compile commands.
478   if (SeenWorkingDirectories.insert("/").second)
479     for (const auto &MappedFile : MappedFileContents)
480       if (llvm::sys::path::is_absolute(MappedFile.first))
481         InMemoryFileSystem->addFile(
482             MappedFile.first, 0,
483             llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
484 
485   bool ProcessingFailed = false;
486   bool FileSkipped = false;
487   // Compute all absolute paths before we run any actions, as those will change
488   // the working directory.
489   std::vector<std::string> AbsolutePaths;
490   AbsolutePaths.reserve(SourcePaths.size());
491   for (const auto &SourcePath : SourcePaths) {
492     auto AbsPath = getAbsolutePath(*OverlayFileSystem, SourcePath);
493     if (!AbsPath) {
494       llvm::errs() << "Skipping " << SourcePath
495                    << ". Error while getting an absolute path: "
496                    << llvm::toString(AbsPath.takeError()) << "\n";
497       continue;
498     }
499     AbsolutePaths.push_back(std::move(*AbsPath));
500   }
501 
502   // Remember the working directory in case we need to restore it.
503   std::string InitialWorkingDir;
504   if (RestoreCWD) {
505     if (auto CWD = OverlayFileSystem->getCurrentWorkingDirectory()) {
506       InitialWorkingDir = std::move(*CWD);
507     } else {
508       llvm::errs() << "Could not get working directory: "
509                    << CWD.getError().message() << "\n";
510     }
511   }
512 
513   for (llvm::StringRef File : AbsolutePaths) {
514     // Currently implementations of CompilationDatabase::getCompileCommands can
515     // change the state of the file system (e.g.  prepare generated headers), so
516     // this method needs to run right before we invoke the tool, as the next
517     // file may require a different (incompatible) state of the file system.
518     //
519     // FIXME: Make the compilation database interface more explicit about the
520     // requirements to the order of invocation of its members.
521     std::vector<CompileCommand> CompileCommandsForFile =
522         Compilations.getCompileCommands(File);
523     if (CompileCommandsForFile.empty()) {
524       llvm::errs() << "Skipping " << File << ". Compile command not found.\n";
525       FileSkipped = true;
526       continue;
527     }
528     for (CompileCommand &CompileCommand : CompileCommandsForFile) {
529       // FIXME: chdir is thread hostile; on the other hand, creating the same
530       // behavior as chdir is complex: chdir resolves the path once, thus
531       // guaranteeing that all subsequent relative path operations work
532       // on the same path the original chdir resulted in. This makes a
533       // difference for example on network filesystems, where symlinks might be
534       // switched during runtime of the tool. Fixing this depends on having a
535       // file system abstraction that allows openat() style interactions.
536       if (OverlayFileSystem->setCurrentWorkingDirectory(
537               CompileCommand.Directory))
538         llvm::report_fatal_error("Cannot chdir into \"" +
539                                  Twine(CompileCommand.Directory) + "\"!");
540 
541       // Now fill the in-memory VFS with the relative file mappings so it will
542       // have the correct relative paths. We never remove mappings but that
543       // should be fine.
544       if (SeenWorkingDirectories.insert(CompileCommand.Directory).second)
545         for (const auto &MappedFile : MappedFileContents)
546           if (!llvm::sys::path::is_absolute(MappedFile.first))
547             InMemoryFileSystem->addFile(
548                 MappedFile.first, 0,
549                 llvm::MemoryBuffer::getMemBuffer(MappedFile.second));
550 
551       std::vector<std::string> CommandLine = CompileCommand.CommandLine;
552       if (ArgsAdjuster)
553         CommandLine = ArgsAdjuster(CommandLine, CompileCommand.Filename);
554       assert(!CommandLine.empty());
555 
556       // Add the resource dir based on the binary of this tool. argv[0] in the
557       // compilation database may refer to a different compiler and we want to
558       // pick up the very same standard library that compiler is using. The
559       // builtin headers in the resource dir need to match the exact clang
560       // version the tool is using.
561       // FIXME: On linux, GetMainExecutable is independent of the value of the
562       // first argument, thus allowing ClangTool and runToolOnCode to just
563       // pass in made-up names here. Make sure this works on other platforms.
564       injectResourceDir(CommandLine, "clang_tool", &StaticSymbol);
565 
566       // FIXME: We need a callback mechanism for the tool writer to output a
567       // customized message for each file.
568       LLVM_DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
569       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
570                                 PCHContainerOps);
571       Invocation.setDiagnosticConsumer(DiagConsumer);
572 
573       if (!Invocation.run()) {
574         // FIXME: Diagnostics should be used instead.
575         if (PrintErrorMessage)
576           llvm::errs() << "Error while processing " << File << ".\n";
577         ProcessingFailed = true;
578       }
579     }
580   }
581 
582   if (!InitialWorkingDir.empty()) {
583     if (auto EC =
584             OverlayFileSystem->setCurrentWorkingDirectory(InitialWorkingDir))
585       llvm::errs() << "Error when trying to restore working dir: "
586                    << EC.message() << "\n";
587   }
588   return ProcessingFailed ? 1 : (FileSkipped ? 2 : 0);
589 }
590 
591 namespace {
592 
593 class ASTBuilderAction : public ToolAction {
594   std::vector<std::unique_ptr<ASTUnit>> &ASTs;
595 
596 public:
597   ASTBuilderAction(std::vector<std::unique_ptr<ASTUnit>> &ASTs) : ASTs(ASTs) {}
598 
599   bool runInvocation(std::shared_ptr<CompilerInvocation> Invocation,
600                      FileManager *Files,
601                      std::shared_ptr<PCHContainerOperations> PCHContainerOps,
602                      DiagnosticConsumer *DiagConsumer) override {
603     std::unique_ptr<ASTUnit> AST = ASTUnit::LoadFromCompilerInvocation(
604         Invocation, std::move(PCHContainerOps),
605         CompilerInstance::createDiagnostics(&Invocation->getDiagnosticOpts(),
606                                             DiagConsumer,
607                                             /*ShouldOwnClient=*/false),
608         Files);
609     if (!AST)
610       return false;
611 
612     ASTs.push_back(std::move(AST));
613     return true;
614   }
615 };
616 
617 } // namespace
618 
619 int ClangTool::buildASTs(std::vector<std::unique_ptr<ASTUnit>> &ASTs) {
620   ASTBuilderAction Action(ASTs);
621   return run(&Action);
622 }
623 
624 void ClangTool::setRestoreWorkingDir(bool RestoreCWD) {
625   this->RestoreCWD = RestoreCWD;
626 }
627 
628 void ClangTool::setPrintErrorMessage(bool PrintErrorMessage) {
629   this->PrintErrorMessage = PrintErrorMessage;
630 }
631 
632 namespace clang {
633 namespace tooling {
634 
635 std::unique_ptr<ASTUnit>
636 buildASTFromCode(StringRef Code, StringRef FileName,
637                  std::shared_ptr<PCHContainerOperations> PCHContainerOps) {
638   return buildASTFromCodeWithArgs(Code, std::vector<std::string>(), FileName,
639                                   "clang-tool", std::move(PCHContainerOps));
640 }
641 
642 std::unique_ptr<ASTUnit> buildASTFromCodeWithArgs(
643     StringRef Code, const std::vector<std::string> &Args, StringRef FileName,
644     StringRef ToolName, std::shared_ptr<PCHContainerOperations> PCHContainerOps,
645     ArgumentsAdjuster Adjuster, const FileContentMappings &VirtualMappedFiles,
646     DiagnosticConsumer *DiagConsumer) {
647   std::vector<std::unique_ptr<ASTUnit>> ASTs;
648   ASTBuilderAction Action(ASTs);
649   llvm::IntrusiveRefCntPtr<llvm::vfs::OverlayFileSystem> OverlayFileSystem(
650       new llvm::vfs::OverlayFileSystem(llvm::vfs::getRealFileSystem()));
651   llvm::IntrusiveRefCntPtr<llvm::vfs::InMemoryFileSystem> InMemoryFileSystem(
652       new llvm::vfs::InMemoryFileSystem);
653   OverlayFileSystem->pushOverlay(InMemoryFileSystem);
654   llvm::IntrusiveRefCntPtr<FileManager> Files(
655       new FileManager(FileSystemOptions(), OverlayFileSystem));
656 
657   ToolInvocation Invocation(
658       getSyntaxOnlyToolArgs(ToolName, Adjuster(Args, FileName), FileName),
659       &Action, Files.get(), std::move(PCHContainerOps));
660   Invocation.setDiagnosticConsumer(DiagConsumer);
661 
662   InMemoryFileSystem->addFile(FileName, 0,
663                               llvm::MemoryBuffer::getMemBufferCopy(Code));
664   for (auto &FilenameWithContent : VirtualMappedFiles) {
665     InMemoryFileSystem->addFile(
666         FilenameWithContent.first, 0,
667         llvm::MemoryBuffer::getMemBuffer(FilenameWithContent.second));
668   }
669 
670   if (!Invocation.run())
671     return nullptr;
672 
673   assert(ASTs.size() == 1);
674   return std::move(ASTs[0]);
675 }
676 
677 } // namespace tooling
678 } // namespace clang
679