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"
16 #include "clang/Serialization/ASTReader.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:
ModuleDependencyListener(ModuleDependencyCollector & Collector)30 ModuleDependencyListener(ModuleDependencyCollector &Collector)
31 : Collector(Collector) {}
needsInputFileVisitation()32 bool needsInputFileVisitation() override { return true; }
needsSystemInputFileVisitation()33 bool needsSystemInputFileVisitation() override { return true; }
visitInputFile(StringRef Filename,bool IsSystem,bool IsOverridden,bool IsExplicitModule)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;
43 SourceManager &SM;
ModuleDependencyPPCallbacks__anonc493ebcc0111::ModuleDependencyPPCallbacks44 ModuleDependencyPPCallbacks(ModuleDependencyCollector &Collector,
45 SourceManager &SM)
46 : Collector(Collector), SM(SM) {}
47
InclusionDirective__anonc493ebcc0111::ModuleDependencyPPCallbacks48 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;
ModuleDependencyMMCallbacks__anonc493ebcc0111::ModuleDependencyMMCallbacks62 ModuleDependencyMMCallbacks(ModuleDependencyCollector &Collector)
63 : Collector(Collector) {}
64
moduleMapAddHeader__anonc493ebcc0111::ModuleDependencyMMCallbacks65 void moduleMapAddHeader(StringRef HeaderPath) override {
66 if (llvm::sys::path::is_absolute(HeaderPath))
67 Collector.addFile(HeaderPath);
68 }
moduleMapAddUmbrellaHeader__anonc493ebcc0111::ModuleDependencyMMCallbacks69 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
attachToASTReader(ASTReader & R)101 void ModuleDependencyCollector::attachToASTReader(ASTReader &R) {
102 R.addListener(std::make_unique<ModuleDependencyListener>(*this));
103 }
104
attachToPreprocessor(Preprocessor & PP)105 void ModuleDependencyCollector::attachToPreprocessor(Preprocessor &PP) {
106 PP.addPPCallbacks(std::make_unique<ModuleDependencyPPCallbacks>(
107 *this, PP.getSourceManager()));
108 PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
109 std::make_unique<ModuleDependencyMMCallbacks>(*this));
110 }
111
isCaseSensitivePath(StringRef Path)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
writeFileMap()130 void ModuleDependencyCollector::writeFileMap() {
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
getRealPath(StringRef SrcPath,SmallVectorImpl<char> & Result)159 bool ModuleDependencyCollector::getRealPath(StringRef SrcPath,
160 SmallVectorImpl<char> &Result) {
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] = std::string(RealPath.str());
174 } else {
175 RealPath = DirWithSymLink->second;
176 }
177
178 path::append(RealPath, FileName);
179 Result.swap(RealPath);
180 return true;
181 }
182
copyToRoot(StringRef Src,StringRef Dst)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
addFile(StringRef Filename,StringRef FileDst)236 void ModuleDependencyCollector::addFile(StringRef Filename, StringRef FileDst) {
237 if (insertSeen(Filename))
238 if (copyToRoot(Filename, FileDst))
239 HasErrors = true;
240 }
241