[PCH] Enhance InputFile to also include whether the file is out-of-date.

Previously we would return null for an out-of-date file. This inhibited ASTReader::ReadSLocEntry
from creating a FileID to recover gracefully in such a case.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176332 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Serialization/ASTReader.h

@@ -924,11 +924,10 @@ private:
   /// \brief Reads a statement from the specified cursor.
   Stmt *ReadStmtFromStream(ModuleFile &F);
 
-  typedef llvm::PointerIntPair<const FileEntry *, 1, bool> InputFile;
-
   /// \brief Retrieve the file entry and 'overridden' bit for an input
   /// file in the given module file.
-  InputFile getInputFile(ModuleFile &F, unsigned ID, bool Complain = true);
+  serialization::InputFile getInputFile(ModuleFile &F, unsigned ID,
+                                        bool Complain = true);
 
   /// \brief Get a FileEntry out of stored-in-PCH filename, making sure we take
   /// into account all the necessary relocations.

include/clang/Serialization/Module.h

@@ -55,6 +55,35 @@ struct DeclContextInfo {
   unsigned NumLexicalDecls;
 };
 
+/// \brief The input file that has been loaded from this AST file, along with
+/// bools indicating whether this was an overridden buffer or if it was
+/// out-of-date.
+class InputFile {
+  enum {
+    Overridden = 1,
+    OutOfDate = 2
+  };
+  llvm::PointerIntPair<const FileEntry *, 2, unsigned> Val;
+
+public:
+  InputFile() {}
+  InputFile(const FileEntry *File,
+            bool isOverridden = false, bool isOutOfDate = false) {
+    assert(!(isOverridden && isOutOfDate) &&
+           "an overridden cannot be out-of-date");
+    unsigned intVal = 0;
+    if (isOverridden)
+      intVal = Overridden;
+    else if (isOutOfDate)
+      intVal = OutOfDate;
+    Val.setPointerAndInt(File, intVal);
+  }
+
+  const FileEntry *getFile() const { return Val.getPointer(); }
+  bool isOverridden() const { return Val.getInt() == Overridden; }
+  bool isOutOfDate() const { return Val.getInt() == OutOfDate; }
+};
+
 /// \brief Information about a module that has been loaded by the ASTReader.
 ///
 /// Each instance of the Module class corresponds to a single AST file, which
@@ -145,10 +174,8 @@ public:
   /// \brief Offsets for all of the input file entries in the AST file.
   const uint32_t *InputFileOffsets;
 
-  /// \brief The input files that have been loaded from this AST file, along
-  /// with a bool indicating whether this was an overridden buffer.
-  std::vector<llvm::PointerIntPair<const FileEntry *, 1, bool> > 
-    InputFilesLoaded;
+  /// \brief The input files that have been loaded from this AST file.
+  std::vector<InputFile> InputFilesLoaded;
 
   // === Source Locations ===
 

lib/Serialization/ASTReader.cpp

@@ -917,10 +917,13 @@ bool ASTReader::ReadSLocEntry(int ID) {
     // we will also try to fail gracefully by setting up the SLocEntry.
     unsigned InputID = Record[4];
     InputFile IF = getInputFile(*F, InputID);
-    const FileEntry *File = IF.getPointer();
-    bool OverriddenBuffer = IF.getInt();
+    const FileEntry *File = IF.getFile();
+    bool OverriddenBuffer = IF.isOverridden();
 
-    if (!IF.getPointer())
+    // Note that we only check if a File was returned. If it was out-of-date
+    // we have complained but we will continue creating a FileID to recover
+    // gracefully.
+    if (!File)
       return true;
 
     SourceLocation IncludeLoc = ReadSourceLocation(*F, Record[1]);
@@ -1495,14 +1498,13 @@ void ASTReader::markIdentifierUpToDate(IdentifierInfo *II) {
     IdentifierGeneration[II] = CurrentGeneration;
 }
 
-llvm::PointerIntPair<const FileEntry *, 1, bool> 
-ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
+InputFile ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
   // If this ID is bogus, just return an empty input file.
   if (ID == 0 || ID > F.InputFilesLoaded.size())
     return InputFile();
 
   // If we've already loaded this input file, return it.
-  if (F.InputFilesLoaded[ID-1].getPointer())
+  if (F.InputFilesLoaded[ID-1].getFile())
     return F.InputFilesLoaded[ID-1];
 
   // Go find this input file.
@@ -1556,17 +1558,15 @@ ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
       }
       return InputFile();
     }
-    
-    // Note that we've loaded this input file.
-    F.InputFilesLoaded[ID-1] = InputFile(File, Overridden);
-    
+
     // Check if there was a request to override the contents of the file
     // that was part of the precompiled header. Overridding such a file
     // can lead to problems when lexing using the source locations from the
     // PCH.
     SourceManager &SM = getSourceManager();
     if (!Overridden && SM.isFileOverridden(File)) {
-      Error(diag::err_fe_pch_file_overridden, Filename);
+      if (Complain)
+        Error(diag::err_fe_pch_file_overridden, Filename);
       // After emitting the diagnostic, recover by disabling the override so
       // that the original file will be used.
       SM.disableFileContentsOverride(File);
@@ -1577,11 +1577,10 @@ ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
                               StoredSize, StoredTime);
     }
 
-    // For an overridden file, there is nothing to validate.
-    if (Overridden)
-      return InputFile(File, Overridden);
+    bool IsOutOfDate = false;
 
-    if ((StoredSize != File->getSize()
+    // For an overridden file, there is nothing to validate.
+    if (!Overridden && (StoredSize != File->getSize()
 #if !defined(LLVM_ON_WIN32)
          // In our regression testing, the Windows file system seems to
          // have inconsistent modification times that sometimes
@@ -1591,11 +1590,14 @@ ASTReader::getInputFile(ModuleFile &F, unsigned ID, bool Complain) {
          )) {
       if (Complain)
         Error(diag::err_fe_pch_file_modified, Filename);
-      
-      return InputFile();
+      IsOutOfDate = true;
     }
 
-    return InputFile(File, Overridden);
+    InputFile IF = InputFile(File, Overridden, IsOutOfDate);
+
+    // Note that we've loaded this input file.
+    F.InputFilesLoaded[ID-1] = IF;
+    return IF;
   }
   }
 
@@ -1668,9 +1670,11 @@ ASTReader::ReadControlBlock(ModuleFile &F,
       // Validate all of the input files.
       if (!DisableValidation) {
         bool Complain = (ClientLoadCapabilities & ARR_OutOfDate) == 0;
-        for (unsigned I = 0, N = Record[0]; I < N; ++I)
-          if (!getInputFile(F, I+1, Complain).getPointer())
+        for (unsigned I = 0, N = Record[0]; I < N; ++I) {
+          InputFile IF = getInputFile(F, I+1, Complain);
+          if (!IF.getFile() || IF.isOutOfDate())
             return OutOfDate;
+        }
       }
       return Success;