Consider module depedencies when checking a preamble in libclang

Add module dependencies (header files, module map files) to the list of
files to check when deciding whether to rebuild a preamble. That fixes
using preambles with module imports so long as they are in
non-overridden files.

My intent is to use to unify the existing dependency collectors to the
new “DependencyCollectory” interface from this commit, starting with the
DependencyFileGenerator.

llvm-svn: 212060

3 files changed, 114 insertions, 15 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index df50c407735..3c2b4235018 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1609,6 +1609,9 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   Clang->setSourceManager(new SourceManager(getDiagnostics(),
                                             Clang->getFileManager()));
 
+  auto PreambleDepCollector = std::make_shared<DependencyCollector>();
+  Clang->addDependencyCollector(PreambleDepCollector);
+
   std::unique_ptr<PrecompilePreambleAction> Act;
   Act.reset(new PrecompilePreambleAction(*this));
   if (!Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0])) {
@@ -1657,29 +1660,20 @@ llvm::MemoryBuffer *ASTUnit::getMainBufferWithPrecompiledPreamble(
   // so we can verify whether they have changed or not.
   FilesInPreamble.clear();
   SourceManager &SourceMgr = Clang->getSourceManager();
-  const llvm::MemoryBuffer *MainFileBuffer
-    = SourceMgr.getBuffer(SourceMgr.getMainFileID());
-  for (SourceManager::fileinfo_iterator F = SourceMgr.fileinfo_begin(),
-                                     FEnd = SourceMgr.fileinfo_end();
-       F != FEnd;
-       ++F) {
-    const FileEntry *File = F->second->OrigEntry;
-    if (!File)
-      continue;
-    const llvm::MemoryBuffer *Buffer = F->second->getRawBuffer();
-    if (Buffer == MainFileBuffer)
+  for (auto &Filename : PreambleDepCollector->getDependencies()) {
+    const FileEntry *File = Clang->getFileManager().getFile(Filename);
+    if (!File || File == SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()))
       continue;
-
     if (time_t ModTime = File->getModificationTime()) {
       FilesInPreamble[File->getName()] = PreambleFileHash::createForFile(
-          F->second->getSize(), ModTime);
+          File->getSize(), ModTime);
     } else {
-      assert(F->second->getSize() == Buffer->getBufferSize());
+      llvm::MemoryBuffer *Buffer = SourceMgr.getMemoryBufferForFile(File);
       FilesInPreamble[File->getName()] =
           PreambleFileHash::createForMemoryBuffer(Buffer);
     }
   }
-  
+
   PreambleRebuildCounter = 1;
   PreprocessorOpts.eraseRemappedFile(
                                PreprocessorOpts.remapped_file_buffer_end() - 1);
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index b5efb14dc2e..60f8ae8fdf0 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -288,6 +288,9 @@ void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
     AttachDependencyGraphGen(*PP, DepOpts.DOTOutputFile,
                              getHeaderSearchOpts().Sysroot);
 
+  for (auto &Listener : DependencyCollectors)
+    Listener->attachToPreprocessor(*PP);
+
   // If we don't have a collector, but we are collecting module dependencies,
   // then we're the top level compiler instance and need to create one.
   if (!ModuleDepCollector && !DepOpts.ModuleDependencyOutputDir.empty())
@@ -1233,6 +1236,9 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
     if (ModuleDepCollector)
       ModuleDepCollector->attachToASTReader(*ModuleManager);
 
+    for (auto &Listener : DependencyCollectors)
+      Listener->attachToASTReader(*ModuleManager);
+
     // Try to load the module file.
     unsigned ARRFlags = ASTReader::ARR_OutOfDate | ASTReader::ARR_Missing;
     switch (ModuleManager->ReadAST(ModuleFileName, serialization::MK_Module,
diff --git a/clang/lib/Frontend/DependencyFile.cpp b/clang/lib/Frontend/DependencyFile.cpp
index e72be89b4e9..0b9c0d47dc3 100644
--- a/clang/lib/Frontend/DependencyFile.cpp
+++ b/clang/lib/Frontend/DependencyFile.cpp
@@ -29,6 +29,105 @@
 using namespace clang;
 
 namespace {
+struct DepCollectorPPCallbacks : public PPCallbacks {
+  DependencyCollector &DepCollector;
+  SourceManager &SM;
+  DepCollectorPPCallbacks(DependencyCollector &L, SourceManager &SM)
+      : DepCollector(L), SM(SM) { }
+
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override {
+    if (Reason != PPCallbacks::EnterFile)
+      return;
+
+    // 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!
+    const FileEntry *FE =
+        SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(Loc)));
+    if (!FE)
+      return;
+
+    StringRef Filename = FE->getName();
+
+    // Remove leading "./" (or ".//" or "././" etc.)
+    while (Filename.size() > 2 && Filename[0] == '.' &&
+           llvm::sys::path::is_separator(Filename[1])) {
+      Filename = Filename.substr(1);
+      while (llvm::sys::path::is_separator(Filename[0]))
+        Filename = Filename.substr(1);
+    }
+
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
+                                   FileType != SrcMgr::C_User,
+                                   /*IsModuleFile*/false, /*IsMissing*/false);
+  }
+
+  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
+                          StringRef FileName, bool IsAngled,
+                          CharSourceRange FilenameRange, const FileEntry *File,
+                          StringRef SearchPath, StringRef RelativePath,
+                          const Module *Imported) override {
+    if (!File)
+      DepCollector.maybeAddDependency(FileName, /*FromModule*/false,
+                                     /*IsSystem*/false, /*IsModuleFile*/false,
+                                     /*IsMissing*/true);
+    // Files that actually exist are handled by FileChanged.
+  }
+
+  void EndOfMainFile() override {
+    DepCollector.finishedMainFile();
+  }
+};
+
+struct DepCollectorASTListener : public ASTReaderListener {
+  DependencyCollector &DepCollector;
+  DepCollectorASTListener(DependencyCollector &L) : DepCollector(L) { }
+  bool needsInputFileVisitation() override { return true; }
+  bool needsSystemInputFileVisitation() override {
+    return DepCollector.needSystemDependencies();
+  }
+  void visitModuleFile(StringRef Filename) override {
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/true,
+                                   /*IsSystem*/false, /*IsModuleFile*/true,
+                                   /*IsMissing*/false);
+  }
+  bool visitInputFile(StringRef Filename, bool IsSystem,
+                      bool IsOverridden) override {
+    if (IsOverridden)
+      return true;
+
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/true, IsSystem,
+                                   /*IsModuleFile*/false, /*IsMissing*/false);
+    return true;
+  }
+};
+} // end anonymous namespace
+
+void DependencyCollector::maybeAddDependency(StringRef Filename, bool FromModule,
+                                            bool IsSystem, bool IsModuleFile,
+                                            bool IsMissing) {
+  if (Seen.insert(Filename) &&
+      sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
+    Dependencies.push_back(Filename);
+}
+
+bool DependencyCollector::sawDependency(StringRef Filename, bool FromModule,
+                                       bool IsSystem, bool IsModuleFile,
+                                       bool IsMissing) {
+  return Filename != "<built-in>" && (needSystemDependencies() || !IsSystem);
+}
+
+DependencyCollector::~DependencyCollector() { }
+void DependencyCollector::attachToPreprocessor(Preprocessor &PP) {
+  PP.addPPCallbacks(new DepCollectorPPCallbacks(*this, PP.getSourceManager()));
+}
+void DependencyCollector::attachToASTReader(ASTReader &R) {
+  R.addListener(new DepCollectorASTListener(*this));
+}
+
+namespace {
 /// Private implementation for DependencyFileGenerator
 class DFGImpl : public PPCallbacks {
   std::vector<std::string> Files;