[PCH] Keep track of file-level declarations that are contained by files.

Introduce a FILE_SORTED_DECLS [de]serialization record that contains
a file sorted array of file-level DeclIDs in a PCH/Module.
The rationale is to allow "targeted" deserialization of decls inside
a range of a source file.

Cocoa PCH increased by 0.8%
Difference of creation time for Cocoa PCH is below the noise level.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143238 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 33 insertions, 1 deletions

diff --git a/include/clang/Serialization/ASTBitCodes.h b/include/clang/Serialization/ASTBitCodes.h
index 9301a833ba..982c31d293 100644
--- a/include/clang/Serialization/ASTBitCodes.h
+++ b/include/clang/Serialization/ASTBitCodes.h
@@ -436,7 +436,10 @@ namespace clang {
 
       /// \brief Record code for ObjC categories in a module that are chained to
       /// an interface.
-      OBJC_CHAINED_CATEGORIES
+      OBJC_CHAINED_CATEGORIES,
+
+      /// \brief Record code for a file sorted array of DeclIDs in a module.
+      FILE_SORTED_DECLS
     };
 
     /// \brief Record types used within a source manager block.
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index a463a280d3..f9ca9b2758 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -296,6 +296,9 @@ private:
   /// \brief Declarations that have been replaced in a later file in the chain.
   DeclReplacementMap ReplacedDecls;
 
+  /// \brief Map from a FileID to the file-level declarations that it contains.
+  llvm::DenseMap<FileID, ArrayRef<serialization::DeclID> > FileDeclIDs;
+
   // Updates for visible decls can occur for other contexts than just the
   // TU, and when we read those update records, the actual context will not
   // be available yet (unless it's the TU), so have this pending map using the
diff --git a/include/clang/Serialization/ASTWriter.h b/include/clang/Serialization/ASTWriter.h
index 184897fba9..52c80d1248 100644
--- a/include/clang/Serialization/ASTWriter.h
+++ b/include/clang/Serialization/ASTWriter.h
@@ -59,6 +59,8 @@ class SwitchCase;
 class TargetInfo;
 class VersionTuple;
 
+namespace SrcMgr { class SLocEntry; }
+
 /// \brief Writes an AST file containing the contents of a translation unit.
 ///
 /// The ASTWriter class produces a bitstream containing the serialized
@@ -144,6 +146,25 @@ private:
   /// the declaration's ID.
   std::vector<serialization::DeclOffset> DeclOffsets;
 
+  /// \brief Vector of pairs of raw location/DeclID.
+  typedef SmallVector<std::pair<unsigned, serialization::DeclID>, 64>
+    LocDeclIDsTy;
+  struct DeclIDInFileInfo {
+    LocDeclIDsTy DeclIDs;
+    /// \brief Set when the DeclIDs vectors from all files are joined, this
+    /// indicates the index that this particular vector has in the global one.
+    unsigned FirstDeclIndex;
+  };
+  typedef llvm::DenseMap<const SrcMgr::SLocEntry *,
+                         DeclIDInFileInfo *> FileDeclIDsTy;
+
+  /// \brief Map from file SLocEntries to info about the file-level declarations
+  /// that it contains.
+  FileDeclIDsTy FileDeclIDs;
+
+  void associateDeclWithFile(const Decl *D, serialization::DeclID,
+                             SourceLocation FileLoc);
+
   /// \brief The first ID number we can use for our own types.
   serialization::TypeID FirstTypeID;
 
@@ -354,6 +375,7 @@ private:
   uint64_t WriteDeclContextLexicalBlock(ASTContext &Context, DeclContext *DC);
   uint64_t WriteDeclContextVisibleBlock(ASTContext &Context, DeclContext *DC);
   void WriteTypeDeclOffsets();
+  void WriteFileDeclIDsMap();
   void WriteSelectors(Sema &SemaRef);
   void WriteReferencedSelectorsPool(Sema &SemaRef);
   void WriteIdentifierTable(Preprocessor &PP, IdentifierResolver &IdResolver,
@@ -393,6 +415,7 @@ public:
   /// \brief Create a new precompiled header writer that outputs to
   /// the given bitstream.
   ASTWriter(llvm::BitstreamWriter &Stream);
+  ~ASTWriter();
                     
   /// \brief Write a precompiled header for the given semantic analysis.
   ///
diff --git a/include/clang/Serialization/Module.h b/include/clang/Serialization/Module.h
index 5c0cc9d296..43687f46dd 100644
--- a/include/clang/Serialization/Module.h
+++ b/include/clang/Serialization/Module.h
@@ -271,6 +271,9 @@ public:
   /// Key is the ID of the interface.
   /// Value is a pair of linked category DeclIDs (head category, tail category).
   ChainedObjCCategoriesMap ChainedObjCCategories;
+
+  /// \brief Array of file-level DeclIDs sorted by file.
+  const serialization::DeclID *FileSortedDecls;
   
   // === Types ===