Improve our uniquing of file entries when files are re-saved or are

overridden via remapping. Thus, when we create a "virtual" file in the
file manager, we still stat() the real file that lives behind it so
that we can provide proper uniquing based on inodes. This helps keep
the file manager much more consistent.

To take advantage of this when reparsing files in libclang, we disable
the use of the stat() cache when reparsing or performing code
completion, since the stat() cache is very likely to be out of date in
this use case.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124971 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 91 insertions, 45 deletions

diff --git a/include/clang/Frontend/CompilerInstance.h b/include/clang/Frontend/CompilerInstance.h
index fd6224bd3c..430cc603c7 100644
--- a/include/clang/Frontend/CompilerInstance.h
+++ b/include/clang/Frontend/CompilerInstance.h
@@ -537,6 +537,7 @@ public:
   /// context.
   void createPCHExternalASTSource(llvm::StringRef Path,
                                   bool DisablePCHValidation,
+                                  bool DisableStatCache,
                                   void *DeserializationListener);
 
   /// Create an external AST source to read a PCH file.
@@ -545,6 +546,7 @@ public:
   static ExternalASTSource *
   createPCHExternalASTSource(llvm::StringRef Path, const std::string &Sysroot,
                              bool DisablePCHValidation,
+                             bool DisableStatCache,
                              Preprocessor &PP, ASTContext &Context,
                              void *DeserializationListener, bool Preamble);
 
diff --git a/include/clang/Frontend/PreprocessorOptions.h b/include/clang/Frontend/PreprocessorOptions.h
index 2a540b61df..0d52e53ea1 100644
--- a/include/clang/Frontend/PreprocessorOptions.h
+++ b/include/clang/Frontend/PreprocessorOptions.h
@@ -48,6 +48,10 @@ public:
   /// precompiled headers.
   bool DisablePCHValidation;
 
+  /// \brief When true, disables the use of the stat cache within a
+  /// precompiled header or AST file.
+  bool DisableStatCache;
+
   /// \brief Dump declarations that are deserialized from PCH, for testing.
   bool DumpDeserializedPCHDecls;
 
@@ -125,7 +129,7 @@ public:
   
 public:
   PreprocessorOptions() : UsePredefines(true), DetailedRecord(false),
-                          DisablePCHValidation(false),
+                          DisablePCHValidation(false), DisableStatCache(false),
                           DumpDeserializedPCHDecls(false),
                           PrecompiledPreambleBytes(0, true),
                           RetainRemappedFileBuffers(false) { }
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index 38b0c57d22..b9bf5f60b6 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -590,6 +590,9 @@ private:
   /// headers when they are loaded.
   bool DisableValidation;
       
+  /// \brief Whether to disable the use of stat caches in AST files.
+  bool DisableStatCache;
+
   /// \brief Mapping from switch-case IDs in the chain to switch-case statements
   ///
   /// Statements usually don't have IDs, but switch cases need them, so that the
@@ -783,8 +786,14 @@ public:
   /// \param DisableValidation If true, the AST reader will suppress most
   /// of its regular consistency checking, allowing the use of precompiled
   /// headers that cannot be determined to be compatible.
+  ///
+  /// \param DisableStatCache If true, the AST reader will ignore the
+  /// stat cache in the AST files. This performance pessimization can
+  /// help when an AST file is being used in cases where the
+  /// underlying files in the file system may have changed, but
+  /// parsing should still continue.
   ASTReader(Preprocessor &PP, ASTContext *Context, const char *isysroot = 0,
-            bool DisableValidation = false);
+            bool DisableValidation = false, bool DisableStatCache = false);
 
   /// \brief Load the AST file without using any pre-initialized Preprocessor.
   ///
@@ -805,9 +814,15 @@ public:
   /// \param DisableValidation If true, the AST reader will suppress most
   /// of its regular consistency checking, allowing the use of precompiled
   /// headers that cannot be determined to be compatible.
+  ///
+  /// \param DisableStatCache If true, the AST reader will ignore the
+  /// stat cache in the AST files. This performance pessimization can
+  /// help when an AST file is being used in cases where the
+  /// underlying files in the file system may have changed, but
+  /// parsing should still continue.
   ASTReader(SourceManager &SourceMgr, FileManager &FileMgr,
             Diagnostic &Diags, const char *isysroot = 0,
-            bool DisableValidation = false);
+            bool DisableValidation = false, bool DisableStatCache = false);
   ~ASTReader();
 
   /// \brief Load the precompiled header designated by the given file
diff --git a/lib/Basic/FileManager.cpp b/lib/Basic/FileManager.cpp
index cbe90bfdc1..138b54cc08 100644
--- a/lib/Basic/FileManager.cpp
+++ b/lib/Basic/FileManager.cpp
@@ -359,12 +359,43 @@ FileManager::getVirtualFile(llvm::StringRef Filename, off_t Size,
   NamedFileEnt.setValue(NON_EXISTENT_FILE);
 
   // We allow the directory to not exist. If it does exist we store it.
-  // 
+  FileEntry *UFE = 0;
   const DirectoryEntry *DirInfo = getDirectoryFromFile(*this, Filename);
+  if (DirInfo) {
+    // Check to see if the file exists. If so, drop the virtual file
+    int FileDescriptor = -1;
+    struct stat StatBuf;
+    const char *InterndFileName = NamedFileEnt.getKeyData();
+    if (getStatValue(InterndFileName, StatBuf, &FileDescriptor) == 0) {
+      // If the stat process opened the file, close it to avoid a FD leak.
+      if (FileDescriptor != -1)
+        close(FileDescriptor);
+
+      StatBuf.st_size = Size;
+      StatBuf.st_mtime = ModificationTime;
+      UFE = &UniqueFiles.getFile(InterndFileName, StatBuf);
+
+      NamedFileEnt.setValue(UFE);
+
+      // If we had already opened this file, close it now so we don't
+      // leak the descriptor. We're not going to use the file
+      // descriptor anyway, since this is a virtual file.
+      if (UFE->FD != -1) {
+        close(UFE->FD); 
+        UFE->FD = -1;
+      }
+
+      // If we already have an entry with this inode, return it.
+      if (UFE->getName()) 
+        return UFE;
+    }
+  }
 
-  FileEntry *UFE = new FileEntry();
-  VirtualFileEntries.push_back(UFE);
-  NamedFileEnt.setValue(UFE);
+  if (!UFE) {
+    UFE = new FileEntry();
+    VirtualFileEntries.push_back(UFE);
+    NamedFileEnt.setValue(UFE);
+  }
 
   // Get the null-terminated file name as stored as the key of the
   // FileEntries map.
@@ -375,23 +406,7 @@ FileManager::getVirtualFile(llvm::StringRef Filename, off_t Size,
   UFE->ModTime = ModificationTime;
   UFE->Dir     = DirInfo;
   UFE->UID     = NextFileUID++;
-  
-  // If this virtual file resolves to a file, also map that file to the 
-  // newly-created file entry.
-  int FileDescriptor = -1;
-  struct stat StatBuf;
-  if (getStatValue(InterndFileName, StatBuf, &FileDescriptor)) {
-    // If the stat process opened the file, close it to avoid a FD leak.
-    if (FileDescriptor != -1)
-      close(FileDescriptor);
-
-    return UFE;
-  }
-  
-  UFE->FD = FileDescriptor;
-  llvm::SmallString<128> FilePath(UFE->Name);
-  llvm::sys::fs::make_absolute(FilePath);
-  FileEntries[FilePath] = UFE;
+  UFE->FD      = -1;
   return UFE;
 }
 
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index 1db81cb13e..1138cd7db0 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -1580,6 +1580,7 @@ bool ASTUnit::Reparse(RemappedFile *RemappedFiles, unsigned NumRemappedFiles) {
 
   // Remap files.
   PreprocessorOptions &PPOpts = Invocation->getPreprocessorOpts();
+  PPOpts.DisableStatCache = true;
   for (PreprocessorOptions::remapped_file_buffer_iterator 
          R = PPOpts.remapped_file_buffer_begin(),
          REnd = PPOpts.remapped_file_buffer_end();
@@ -1948,6 +1949,7 @@ void ASTUnit::CodeComplete(llvm::StringRef File, unsigned Line, unsigned Column,
 
   // If the main file has been overridden due to the use of a preamble,
   // make that override happen and introduce the preamble.
+  PreprocessorOpts.DisableStatCache = true;
   StoredDiagnostics.insert(StoredDiagnostics.end(),
                            this->StoredDiagnostics.begin(),
              this->StoredDiagnostics.begin() + NumStoredDiagnosticsFromDriver);
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 92aed39b5c..412e7111e4 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -234,11 +234,13 @@ void CompilerInstance::createASTContext() {
 
 void CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path,
                                                   bool DisablePCHValidation,
+                                                  bool DisableStatCache,
                                                  void *DeserializationListener){
   llvm::OwningPtr<ExternalASTSource> Source;
   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
-                                          DisablePCHValidation,
+                                          DisablePCHValidation, 
+                                          DisableStatCache,
                                           getPreprocessor(), getASTContext(),
                                           DeserializationListener,
                                           Preamble));
@@ -249,6 +251,7 @@ ExternalASTSource *
 CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path,
                                              const std::string &Sysroot,
                                              bool DisablePCHValidation,
+                                             bool DisableStatCache,
                                              Preprocessor &PP,
                                              ASTContext &Context,
                                              void *DeserializationListener,
@@ -256,7 +259,7 @@ CompilerInstance::createPCHExternalASTSource(llvm::StringRef Path,
   llvm::OwningPtr<ASTReader> Reader;
   Reader.reset(new ASTReader(PP, &Context,
                              Sysroot.empty() ? 0 : Sysroot.c_str(),
-                             DisablePCHValidation));
+                             DisablePCHValidation, DisableStatCache));
 
   Reader->setDeserializationListener(
             static_cast<ASTDeserializationListener *>(DeserializationListener));
diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 5f78fb1772..af23923002 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -224,6 +224,7 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
       CI.createPCHExternalASTSource(
                                 CI.getPreprocessorOpts().ImplicitPCHInclude,
                                 CI.getPreprocessorOpts().DisablePCHValidation,
+                                CI.getPreprocessorOpts().DisableStatCache,
                                 DeserialListener);
       if (!CI.getASTContext().getExternalSource())
         goto failure;
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index a1908126ef..9206b1bed6 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -505,8 +505,6 @@ static void maybeSynthesizeBlockSignature(TypeProcessingState &state,
         break;
       }
     }
-    assert(!isOnlyParens &&
-           "non-empty abstract-declarator contained only parens!");
   }
 #endif
 
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 68e2e79dde..d2d20bfdbd 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2034,12 +2034,14 @@ ASTReader::ReadASTBlock(PerFileData &F) {
       break;
 
     case STAT_CACHE: {
-      ASTStatCache *MyStatCache =
-        new ASTStatCache((const unsigned char *)BlobStart + Record[0],
-                         (const unsigned char *)BlobStart,
-                         NumStatHits, NumStatMisses);
-      FileMgr.addStatCache(MyStatCache);
-      F.StatCache = MyStatCache;
+      if (!DisableStatCache) {
+        ASTStatCache *MyStatCache =
+          new ASTStatCache((const unsigned char *)BlobStart + Record[0],
+                           (const unsigned char *)BlobStart,
+                           NumStatHits, NumStatMisses);
+        FileMgr.addStatCache(MyStatCache);
+        F.StatCache = MyStatCache;
+      }
       break;
     }
 
@@ -4668,28 +4670,32 @@ void ASTReader::FinishedDeserializing() {
 }
 
 ASTReader::ASTReader(Preprocessor &PP, ASTContext *Context,
-                     const char *isysroot, bool DisableValidation)
+                     const char *isysroot, bool DisableValidation,
+                     bool DisableStatCache)
   : Listener(new PCHValidator(PP, *this)), DeserializationListener(0),
     SourceMgr(PP.getSourceManager()), FileMgr(PP.getFileManager()),
     Diags(PP.getDiagnostics()), SemaObj(0), PP(&PP), Context(Context),
     Consumer(0), isysroot(isysroot), DisableValidation(DisableValidation),
-    NumStatHits(0), NumStatMisses(0), NumSLocEntriesRead(0),
-    TotalNumSLocEntries(0), NextSLocOffset(0), NumStatementsRead(0),
-    TotalNumStatements(0), NumMacrosRead(0), TotalNumMacros(0),
-    NumSelectorsRead(0), NumMethodPoolEntriesRead(0), NumMethodPoolMisses(0),
-    TotalNumMethodPoolEntries(0), NumLexicalDeclContextsRead(0),
-    TotalLexicalDeclContexts(0), NumVisibleDeclContextsRead(0),
-    TotalVisibleDeclContexts(0), NumCurrentElementsDeserializing(0) {
+    DisableStatCache(DisableStatCache), NumStatHits(0), NumStatMisses(0), 
+    NumSLocEntriesRead(0), TotalNumSLocEntries(0), NextSLocOffset(0), 
+    NumStatementsRead(0), TotalNumStatements(0), NumMacrosRead(0), 
+    TotalNumMacros(0), NumSelectorsRead(0), NumMethodPoolEntriesRead(0), 
+    NumMethodPoolMisses(0), TotalNumMethodPoolEntries(0), 
+    NumLexicalDeclContextsRead(0), TotalLexicalDeclContexts(0), 
+    NumVisibleDeclContextsRead(0), TotalVisibleDeclContexts(0), 
+    NumCurrentElementsDeserializing(0) 
+{
   RelocatablePCH = false;
 }
 
 ASTReader::ASTReader(SourceManager &SourceMgr, FileManager &FileMgr,
                      Diagnostic &Diags, const char *isysroot,
-                     bool DisableValidation)
+                     bool DisableValidation, bool DisableStatCache)
   : DeserializationListener(0), SourceMgr(SourceMgr), FileMgr(FileMgr),
     Diags(Diags), SemaObj(0), PP(0), Context(0), Consumer(0),
-    isysroot(isysroot), DisableValidation(DisableValidation), NumStatHits(0),
-    NumStatMisses(0), NumSLocEntriesRead(0), TotalNumSLocEntries(0),
+    isysroot(isysroot), DisableValidation(DisableValidation), 
+    DisableStatCache(DisableStatCache), NumStatHits(0), NumStatMisses(0), 
+    NumSLocEntriesRead(0), TotalNumSLocEntries(0),
     NextSLocOffset(0), NumStatementsRead(0), TotalNumStatements(0),
     NumMacrosRead(0), TotalNumMacros(0), NumSelectorsRead(0),
     NumMethodPoolEntriesRead(0), NumMethodPoolMisses(0),