1 files changed, 207 insertions, 0 deletions
diff --git a/contrib/llvm-project/clang/lib/Frontend/ModuleDependencyCollector.cpp b/contrib/llvm-project/clang/lib/Frontend/ModuleDependencyCollector.cpp
new file mode 100644
index 000000000000..b4b312bc93b9
--- /dev/null
+++ b/contrib/llvm-project/clang/lib/Frontend/ModuleDependencyCollector.cpp
@@ -0,0 +1,207 @@
+//===--- ModuleDependencyCollector.cpp - Collect module dependencies ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Collect the dependencies of a set of modules.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/CharInfo.h"
+#include "clang/Frontend/Utils.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Serialization/ASTReader.h"
+#include "llvm/ADT/iterator_range.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+
+namespace {
+/// Private implementations for ModuleDependencyCollector
+class ModuleDependencyListener : public ASTReaderListener {
+  ModuleDependencyCollector &Collector;
+  FileManager &FileMgr;
+public:
+  ModuleDependencyListener(ModuleDependencyCollector &Collector,
+                           FileManager &FileMgr)
+      : Collector(Collector), FileMgr(FileMgr) {}
+  bool needsInputFileVisitation() override { return true; }
+  bool needsSystemInputFileVisitation() override { return true; }
+  bool visitInputFile(StringRef Filename, bool IsSystem, bool IsOverridden,
+                      bool IsExplicitModule) override {
+    // Run this through the FileManager in order to respect 'use-external-name'
+    // in case we have a VFS overlay.
+    if (auto FE = FileMgr.getOptionalFileRef(Filename))
+      Filename = FE->getName();
+    Collector.addFile(Filename);
+    return true;
+  }
+};
+
+struct ModuleDependencyPPCallbacks : public PPCallbacks {
+  ModuleDependencyCollector &Collector;
+  SourceManager &SM;
+  ModuleDependencyPPCallbacks(ModuleDependencyCollector &Collector,
+                              SourceManager &SM)
+      : Collector(Collector), SM(SM) {}
+
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange,
+                          OptionalFileEntryRef File, StringRef SearchPath,
+                          StringRef RelativePath, const Module *Imported,
+                          SrcMgr::CharacteristicKind FileType) override {
+    if (!File)
+      return;
+    Collector.addFile(File->getName());
+  }
+};
+
+struct ModuleDependencyMMCallbacks : public ModuleMapCallbacks {
+  ModuleDependencyCollector &Collector;
+  ModuleDependencyMMCallbacks(ModuleDependencyCollector &Collector)
+      : Collector(Collector) {}
+
+  void moduleMapAddHeader(StringRef HeaderPath) override {
+    if (llvm::sys::path::is_absolute(HeaderPath))
+      Collector.addFile(HeaderPath);
+  }
+  void moduleMapAddUmbrellaHeader(FileManager *FileMgr,
+                                  const FileEntry *Header) override {
+    StringRef HeaderFilename = Header->getName();
+    moduleMapAddHeader(HeaderFilename);
+    // The FileManager can find and cache the symbolic link for a framework
+    // header before its real path, this means a module can have some of its
+    // headers to use other paths. Although this is usually not a problem, it's
+    // inconsistent, and not collecting the original path header leads to
+    // umbrella clashes while rebuilding modules in the crash reproducer. For
+    // example:
+    //    ApplicationServices.framework/Frameworks/ImageIO.framework/ImageIO.h
+    // instead of:
+    //    ImageIO.framework/ImageIO.h
+    //
+    // FIXME: this shouldn't be necessary once we have FileName instances
+    // around instead of FileEntry ones. For now, make sure we collect all
+    // that we need for the reproducer to work correctly.
+    StringRef UmbreallDirFromHeader =
+        llvm::sys::path::parent_path(HeaderFilename);
+    StringRef UmbrellaDir = Header->getDir()->getName();
+    if (!UmbrellaDir.equals(UmbreallDirFromHeader)) {
+      SmallString<128> AltHeaderFilename;
+      llvm::sys::path::append(AltHeaderFilename, UmbrellaDir,
+                              llvm::sys::path::filename(HeaderFilename));
+      if (FileMgr->getFile(AltHeaderFilename))
+        moduleMapAddHeader(AltHeaderFilename);
+    }
+  }
+};
+
+}
+
+void ModuleDependencyCollector::attachToASTReader(ASTReader &R) {
+  R.addListener(
+      std::make_unique<ModuleDependencyListener>(*this, R.getFileManager()));
+}
+
+void ModuleDependencyCollector::attachToPreprocessor(Preprocessor &PP) {
+  PP.addPPCallbacks(std::make_unique<ModuleDependencyPPCallbacks>(
+      *this, PP.getSourceManager()));
+  PP.getHeaderSearchInfo().getModuleMap().addModuleMapCallbacks(
+      std::make_unique<ModuleDependencyMMCallbacks>(*this));
+}
+
+static bool isCaseSensitivePath(StringRef Path) {
+  SmallString<256> TmpDest = Path, UpperDest, RealDest;
+  // Remove component traversals, links, etc.
+  if (llvm::sys::fs::real_path(Path, TmpDest))
+    return true; // Current default value in vfs.yaml
+  Path = TmpDest;
+
+  // Change path to all upper case and ask for its real path, if the latter
+  // exists and is equal to Path, it's not case sensitive. Default to case
+  // sensitive in the absence of realpath, since this is what the VFSWriter
+  // already expects when sensitivity isn't setup.
+  for (auto &C : Path)
+    UpperDest.push_back(toUppercase(C));
+  if (!llvm::sys::fs::real_path(UpperDest, RealDest) && Path.equals(RealDest))
+    return false;
+  return true;
+}
+
+void ModuleDependencyCollector::writeFileMap() {
+  if (Seen.empty())
+    return;
+
+  StringRef VFSDir = getDest();
+
+  // Default to use relative overlay directories in the VFS yaml file. This
+  // allows crash reproducer scripts to work across machines.
+  VFSWriter.setOverlayDir(VFSDir);
+
+  // Explicitly set case sensitivity for the YAML writer. For that, find out
+  // the sensitivity at the path where the headers all collected to.
+  VFSWriter.setCaseSensitivity(isCaseSensitivePath(VFSDir));
+
+  // Do not rely on real path names when executing the crash reproducer scripts
+  // since we only want to actually use the files we have on the VFS cache.
+  VFSWriter.setUseExternalNames(false);
+
+  std::error_code EC;
+  SmallString<256> YAMLPath = VFSDir;
+  llvm::sys::path::append(YAMLPath, "vfs.yaml");
+  llvm::raw_fd_ostream OS(YAMLPath, EC, llvm::sys::fs::OF_TextWithCRLF);
+  if (EC) {
+    HasErrors = true;
+    return;
+  }
+  VFSWriter.write(OS);
+}
+
+std::error_code ModuleDependencyCollector::copyToRoot(StringRef Src,
+                                                      StringRef Dst) {
+  using namespace llvm::sys;
+  llvm::FileCollector::PathCanonicalizer::PathStorage Paths =
+      Canonicalizer.canonicalize(Src);
+
+  SmallString<256> CacheDst = getDest();
+
+  if (Dst.empty()) {
+    // The common case is to map the virtual path to the same path inside the
+    // cache.
+    path::append(CacheDst, path::relative_path(Paths.CopyFrom));
+  } else {
+    // When collecting entries from input vfsoverlays, copy the external
+    // contents into the cache but still map from the source.
+    if (!fs::exists(Dst))
+      return std::error_code();
+    path::append(CacheDst, Dst);
+    Paths.CopyFrom = Dst;
+  }
+
+  // Copy the file into place.
+  if (std::error_code EC = fs::create_directories(path::parent_path(CacheDst),
+                                                  /*IgnoreExisting=*/true))
+    return EC;
+  if (std::error_code EC = fs::copy_file(Paths.CopyFrom, CacheDst))
+    return EC;
+
+  // Always map a canonical src path to its real path into the YAML, by doing
+  // this we map different virtual src paths to the same entry in the VFS
+  // overlay, which is a way to emulate symlink inside the VFS; this is also
+  // needed for correctness, not doing that can lead to module redefinition
+  // errors.
+  addFileMapping(Paths.VirtualPath, CacheDst);
+  return std::error_code();
+}
+
+void ModuleDependencyCollector::addFile(StringRef Filename, StringRef FileDst) {
+  if (insertSeen(Filename))
+    if (copyToRoot(Filename, FileDst))
+      HasErrors = true;
+}