clang  10.0.0svn
ModuleDependencyCollector.cpp
Go to the documentation of this file.
1 //===--- ModuleDependencyCollector.cpp - Collect module dependencies ------===//
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 // Collect the dependencies of a set of modules.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/Basic/CharInfo.h"
14 #include "clang/Frontend/Utils.h"
15 #include "clang/Lex/Preprocessor.h"
17 #include "llvm/ADT/iterator_range.h"
18 #include "llvm/Config/llvm-config.h"
19 #include "llvm/Support/FileSystem.h"
20 #include "llvm/Support/Path.h"
21 #include "llvm/Support/raw_ostream.h"
22 
23 using namespace clang;
24 
25 namespace {
26 /// Private implementations for ModuleDependencyCollector
27 class ModuleDependencyListener : public ASTReaderListener {
28  ModuleDependencyCollector &Collector;
29 public:
30  ModuleDependencyListener(ModuleDependencyCollector &Collector)
31  : Collector(Collector) {}
32  bool needsInputFileVisitation() override { return true; }
33  bool needsSystemInputFileVisitation() override { return true; }
34  bool visitInputFile(StringRef Filename, bool IsSystem, bool IsOverridden,
35  bool IsExplicitModule) override {
36  Collector.addFile(Filename);
37  return true;
38  }
39 };
40 
41 struct ModuleDependencyPPCallbacks : public PPCallbacks {
42  ModuleDependencyCollector &Collector;
44  ModuleDependencyPPCallbacks(ModuleDependencyCollector &Collector,
45  SourceManager &SM)
46  : Collector(Collector), SM(SM) {}
47 
48  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
49  StringRef FileName, bool IsAngled,
50  CharSourceRange FilenameRange, const FileEntry *File,
51  StringRef SearchPath, StringRef RelativePath,
52  const Module *Imported,
53  SrcMgr::CharacteristicKind FileType) override {
54  if (!File)
55  return;
56  Collector.addFile(File->getName());
57  }
58 };
59 
60 struct ModuleDependencyMMCallbacks : public ModuleMapCallbacks {
61  ModuleDependencyCollector &Collector;
62  ModuleDependencyMMCallbacks(ModuleDependencyCollector &Collector)
63  : Collector(Collector) {}
64 
65  void moduleMapAddHeader(StringRef HeaderPath) override {
66  if (llvm::sys::path::is_absolute(HeaderPath))
67  Collector.addFile(HeaderPath);
68  }
69  void moduleMapAddUmbrellaHeader(FileManager *FileMgr,
70  const FileEntry *Header) override {
71  StringRef HeaderFilename = Header->getName();
72  moduleMapAddHeader(HeaderFilename);
73  // The FileManager can find and cache the symbolic link for a framework
74  // header before its real path, this means a module can have some of its
75  // headers to use other paths. Although this is usually not a problem, it's
76  // inconsistent, and not collecting the original path header leads to
77  // umbrella clashes while rebuilding modules in the crash reproducer. For
78  // example:
79  // ApplicationServices.framework/Frameworks/ImageIO.framework/ImageIO.h
80  // instead of:
81  // ImageIO.framework/ImageIO.h
82  //
83  // FIXME: this shouldn't be necessary once we have FileName instances
84  // around instead of FileEntry ones. For now, make sure we collect all
85  // that we need for the reproducer to work correctly.
86  StringRef UmbreallDirFromHeader =
87  llvm::sys::path::parent_path(HeaderFilename);
88  StringRef UmbrellaDir = Header->getDir()->getName();
89  if (!UmbrellaDir.equals(UmbreallDirFromHeader)) {
90  SmallString<128> AltHeaderFilename;
91  llvm::sys::path::append(AltHeaderFilename, UmbrellaDir,
92  llvm::sys::path::filename(HeaderFilename));
93  if (FileMgr->getFile(AltHeaderFilename))
94  moduleMapAddHeader(AltHeaderFilename);
95  }
96  }
97 };
98 
99 }
100 
102  R.addListener(std::make_unique<ModuleDependencyListener>(*this));
103 }
104 
106  PP.addPPCallbacks(std::make_unique<ModuleDependencyPPCallbacks>(
107  *this, PP.getSourceManager()));
109  std::make_unique<ModuleDependencyMMCallbacks>(*this));
110 }
111 
112 static bool isCaseSensitivePath(StringRef Path) {
113  SmallString<256> TmpDest = Path, UpperDest, RealDest;
114  // Remove component traversals, links, etc.
115  if (llvm::sys::fs::real_path(Path, TmpDest))
116  return true; // Current default value in vfs.yaml
117  Path = TmpDest;
118 
119  // Change path to all upper case and ask for its real path, if the latter
120  // exists and is equal to Path, it's not case sensitive. Default to case
121  // sensitive in the absence of realpath, since this is what the VFSWriter
122  // already expects when sensitivity isn't setup.
123  for (auto &C : Path)
124  UpperDest.push_back(toUppercase(C));
125  if (!llvm::sys::fs::real_path(UpperDest, RealDest) && Path.equals(RealDest))
126  return false;
127  return true;
128 }
129 
131  if (Seen.empty())
132  return;
133 
134  StringRef VFSDir = getDest();
135 
136  // Default to use relative overlay directories in the VFS yaml file. This
137  // allows crash reproducer scripts to work across machines.
138  VFSWriter.setOverlayDir(VFSDir);
139 
140  // Explicitly set case sensitivity for the YAML writer. For that, find out
141  // the sensitivity at the path where the headers all collected to.
142  VFSWriter.setCaseSensitivity(isCaseSensitivePath(VFSDir));
143 
144  // Do not rely on real path names when executing the crash reproducer scripts
145  // since we only want to actually use the files we have on the VFS cache.
146  VFSWriter.setUseExternalNames(false);
147 
148  std::error_code EC;
149  SmallString<256> YAMLPath = VFSDir;
150  llvm::sys::path::append(YAMLPath, "vfs.yaml");
151  llvm::raw_fd_ostream OS(YAMLPath, EC, llvm::sys::fs::OF_Text);
152  if (EC) {
153  HasErrors = true;
154  return;
155  }
156  VFSWriter.write(OS);
157 }
158 
159 bool ModuleDependencyCollector::getRealPath(StringRef SrcPath,
161  using namespace llvm::sys;
162  SmallString<256> RealPath;
163  StringRef FileName = path::filename(SrcPath);
164  std::string Dir = path::parent_path(SrcPath).str();
165  auto DirWithSymLink = SymLinkMap.find(Dir);
166 
167  // Use real_path to fix any symbolic link component present in a path.
168  // Computing the real path is expensive, cache the search through the
169  // parent path directory.
170  if (DirWithSymLink == SymLinkMap.end()) {
171  if (llvm::sys::fs::real_path(Dir, RealPath))
172  return false;
173  SymLinkMap[Dir] = RealPath.str();
174  } else {
175  RealPath = DirWithSymLink->second;
176  }
177 
178  path::append(RealPath, FileName);
179  Result.swap(RealPath);
180  return true;
181 }
182 
183 std::error_code ModuleDependencyCollector::copyToRoot(StringRef Src,
184  StringRef Dst) {
185  using namespace llvm::sys;
186 
187  // We need an absolute src path to append to the root.
188  SmallString<256> AbsoluteSrc = Src;
189  fs::make_absolute(AbsoluteSrc);
190  // Canonicalize src to a native path to avoid mixed separator styles.
191  path::native(AbsoluteSrc);
192  // Remove redundant leading "./" pieces and consecutive separators.
193  AbsoluteSrc = path::remove_leading_dotslash(AbsoluteSrc);
194 
195  // Canonicalize the source path by removing "..", "." components.
196  SmallString<256> VirtualPath = AbsoluteSrc;
197  path::remove_dots(VirtualPath, /*remove_dot_dot=*/true);
198 
199  // If a ".." component is present after a symlink component, remove_dots may
200  // lead to the wrong real destination path. Let the source be canonicalized
201  // like that but make sure we always use the real path for the destination.
202  SmallString<256> CopyFrom;
203  if (!getRealPath(AbsoluteSrc, CopyFrom))
204  CopyFrom = VirtualPath;
205  SmallString<256> CacheDst = getDest();
206 
207  if (Dst.empty()) {
208  // The common case is to map the virtual path to the same path inside the
209  // cache.
210  path::append(CacheDst, path::relative_path(CopyFrom));
211  } else {
212  // When collecting entries from input vfsoverlays, copy the external
213  // contents into the cache but still map from the source.
214  if (!fs::exists(Dst))
215  return std::error_code();
216  path::append(CacheDst, Dst);
217  CopyFrom = Dst;
218  }
219 
220  // Copy the file into place.
221  if (std::error_code EC = fs::create_directories(path::parent_path(CacheDst),
222  /*IgnoreExisting=*/true))
223  return EC;
224  if (std::error_code EC = fs::copy_file(CopyFrom, CacheDst))
225  return EC;
226 
227  // Always map a canonical src path to its real path into the YAML, by doing
228  // this we map different virtual src paths to the same entry in the VFS
229  // overlay, which is a way to emulate symlink inside the VFS; this is also
230  // needed for correctness, not doing that can lead to module redefinition
231  // errors.
232  addFileMapping(VirtualPath, CacheDst);
233  return std::error_code();
234 }
235 
236 void ModuleDependencyCollector::addFile(StringRef Filename, StringRef FileDst) {
237  if (insertSeen(Filename))
238  if (copyToRoot(Filename, FileDst))
239  HasErrors = true;
240 }
Implements support for file system lookup, file system caching, and directory search management...
Definition: FileManager.h:171
void attachToASTReader(ASTReader &R) override
CharacteristicKind
Indicates whether a file or directory holds normal user code, system code, or system code which is im...
Definition: SourceManager.h:77
ModuleMap & getModuleMap()
Retrieve the module map.
Definition: HeaderSearch.h:652
This interface provides a way to observe the actions of the preprocessor as it does its thing...
Definition: PPCallbacks.h:35
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
Describes a module or submodule.
Definition: Module.h:64
HeaderSearch & getHeaderSearchInfo() const
Definition: Preprocessor.h:909
void attachToPreprocessor(Preprocessor &PP) override
void addModuleMapCallbacks(std::unique_ptr< ModuleMapCallbacks > Callback)
Add a module map callback.
Definition: ModuleMap.h:413
StringRef Filename
Definition: Format.cpp:1807
Represents a character-granular source range.
Defines the clang::Preprocessor interface.
A mechanism to observe the actions of the module map parser as it reads module map files...
Definition: ModuleMap.h:46
Record the location of an inclusion directive, such as an #include or #import statement.
Collects the dependencies for imported modules into a directory.
Definition: Utils.h:154
The result type of a method or function.
const SourceManager & SM
Definition: Format.cpp:1667
SourceManager & getSourceManager() const
Definition: Preprocessor.h:908
const DirectoryEntry * getDir() const
Return the directory the file lives in.
Definition: FileManager.h:111
void addListener(std::unique_ptr< ASTReaderListener > L)
Add an AST callback listener.
Definition: ASTReader.h:1587
Encodes a location in the source.
StringRef getName() const
Definition: FileManager.h:102
Cached information about one file (either on disk or in the virtual file system). ...
Definition: FileManager.h:78
virtual void addFile(StringRef Filename, StringRef FileDst={})
Dataflow Directional Tag Classes.
static bool isCaseSensitivePath(StringRef Path)
Reads an AST files chain containing the contents of a translation unit.
Definition: ASTReader.h:354
llvm::ErrorOr< const FileEntry * > getFile(StringRef Filename, bool OpenFile=false, bool CacheFailure=true)
Lookup, cache, and verify the specified file (real or virtual).
Abstract interface for callback invocations by the ASTReader.
Definition: ASTReader.h:126
LLVM_READONLY char toUppercase(char c)
Converts the given ASCII character to its uppercase equivalent.
Definition: CharInfo.h:173
void addPPCallbacks(std::unique_ptr< PPCallbacks > C)
Definition: Preprocessor.h:996
This class handles loading and caching of source files into memory.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:125
StringRef getName() const
Definition: FileManager.h:52