1 files changed, 18 insertions, 12 deletions

diff --git a/clang/lib/Frontend/DependencyFile.cpp b/clang/lib/Frontend/DependencyFile.cpp
index 06ddb0f0db20..fe4218b6e672 100644
--- a/clang/lib/Frontend/DependencyFile.cpp
+++ b/clang/lib/Frontend/DependencyFile.cpp
@@ -21,10 +21,10 @@
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/ADT/StringSet.h"
-#include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
+#include <optional>
 
 using namespace clang;
 
@@ -44,7 +44,7 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
     // Dependency generation really does want to go all the way to the
     // file entry for a source location to find out what is depended on.
     // We do not want #line markers to affect dependency generation!
-    if (Optional<StringRef> Filename =
+    if (std::optional<StringRef> Filename =
             PP.getSourceManager().getNonBuiltinFilenameForID(FID))
       DepCollector.maybeAddDependency(
           llvm::sys::path::remove_leading_dotslash(*Filename),
@@ -65,7 +65,7 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
   void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
                           StringRef FileName, bool IsAngled,
                           CharSourceRange FilenameRange,
-                          Optional<FileEntryRef> File, StringRef SearchPath,
+                          OptionalFileEntryRef File, StringRef SearchPath,
                           StringRef RelativePath, const Module *Imported,
                           SrcMgr::CharacteristicKind FileType) override {
     if (!File)
@@ -76,7 +76,7 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
   }
 
   void HasInclude(SourceLocation Loc, StringRef SpelledFilename, bool IsAngled,
-                  Optional<FileEntryRef> File,
+                  OptionalFileEntryRef File,
                   SrcMgr::CharacteristicKind FileType) override {
     if (!File)
       return;
@@ -109,7 +109,9 @@ struct DepCollectorMMCallbacks : public ModuleMapCallbacks {
 
 struct DepCollectorASTListener : public ASTReaderListener {
   DependencyCollector &DepCollector;
-  DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
+  FileManager &FileMgr;
+  DepCollectorASTListener(DependencyCollector &L, FileManager &FileMgr)
+      : DepCollector(L), FileMgr(FileMgr) {}
   bool needsInputFileVisitation() override { return true; }
   bool needsSystemInputFileVisitation() override {
     return DepCollector.needSystemDependencies();
@@ -125,6 +127,11 @@ struct DepCollectorASTListener : public ASTReaderListener {
     if (IsOverridden || IsExplicitModule)
       return true;
 
+    // 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();
+
     DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
                                    /*IsModuleFile*/false, /*IsMissing*/false);
     return true;
@@ -160,10 +167,7 @@ bool DependencyCollector::addDependency(StringRef Filename) {
 }
 
 static bool isSpecialFilename(StringRef Filename) {
-  return llvm::StringSwitch<bool>(Filename)
-      .Case("<built-in>", true)
-      .Case("<stdin>", true)
-      .Default(false);
+  return Filename == "<built-in>";
 }
 
 bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
@@ -180,7 +184,8 @@ void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
       std::make_unique<DepCollectorMMCallbacks>(*this));
 }
 void DependencyCollector::attachToASTReader(ASTReader &R) {
-  R.addListener(std::make_unique<DepCollectorASTListener>(*this));
+  R.addListener(
+      std::make_unique<DepCollectorASTListener>(*this, R.getFileManager()));
 }
 
 DependencyFileGenerator::DependencyFileGenerator(
@@ -329,7 +334,7 @@ void DependencyFileGenerator::outputDependencyFile(DiagnosticsEngine &Diags) {
 void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) {
   // Write out the dependency targets, trying to avoid overly long
   // lines when possible. We try our best to emit exactly the same
-  // dependency file as GCC (4.2), assuming the included files are the
+  // dependency file as GCC>=10, assuming the included files are the
   // same.
   const unsigned MaxColumns = 75;
   unsigned Columns = 0;
@@ -356,6 +361,8 @@ void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) {
   // duplicates.
   ArrayRef<std::string> Files = getDependencies();
   for (StringRef File : Files) {
+    if (File == "<stdin>")
+      continue;
     // Start a new line if this would exceed the column limit. Make
     // sure to leave space for a trailing " \" in case we need to
     // break the line on the next iteration.
@@ -376,7 +383,6 @@ void DependencyFileGenerator::outputDependencyFile(llvm::raw_ostream &OS) {
     for (auto I = Files.begin(), E = Files.end(); I != E; ++I) {
       if (Index++ == InputFileIndex)
         continue;
-      OS << '\n';
       PrintFilename(OS, *I, OutputFormat);
       OS << ":\n";
     }