[Clang importer] Refactor and centralize name mapping

include/swift/AST/Identifier.h

@@ -438,34 +438,6 @@ class ObjCSelector {
   /// \param scratch Scratch space to use.
   StringRef getString(llvm::SmallVectorImpl<char> &scratch) const;
 
-  /// Ask whether this selector is a nullary selector (taking no
-  /// arguments) whose name matches the given piece.
-  bool isNullarySelector(StringRef piece) const {
-    if (Storage.isSimpleName()) {
-      return Storage.getBaseName().str() == piece;
-    } else {
-      return false;
-    }
-  }
-
-  /// Ask whether this selector is a non-nullary selector matching the
-  /// given literal pieces.
-  bool isNonNullarySelector(ArrayRef<StringRef> pieces) const {
-    if (Storage.isSimpleName()) {
-      return false;
-    }
-
-    ArrayRef<Identifier> args = Storage.getArgumentNames();
-    if (args.size() != pieces.size())
-      return false;
-
-    for (size_t i = 0, e = args.size(); i != e; ++i) {
-      if (args[i].str() != pieces[i])
-        return false;
-    }
-    return true;
-  }
-
   void *getOpaqueValue() const { return Storage.getOpaqueValue(); }
   static ObjCSelector getFromOpaqueValue(void *p) {
     return ObjCSelector(DeclName::getFromOpaqueValue(p));

include/swift/Basic/StringExtras.h

@@ -51,6 +51,14 @@ namespace swift {
   /// Determine the part of speech for the given word.
   PartOfSpeech getPartOfSpeech(StringRef word);
 
+  /// Scratch space used for returning a set of StringRefs.
+  class StringScratchSpace {
+    llvm::BumpPtrAllocator Allocator;
+
+  public:
+    StringRef copyString(StringRef string);
+  };
+
   namespace camel_case {
     class WordIterator;
 
@@ -219,6 +227,16 @@ namespace swift {
     /// unchanged.
     StringRef toLowercaseWord(StringRef string, SmallVectorImpl<char> &scratch);
 
+    /// Lowercase the first word within the given camelCase string.
+    ///
+    /// \param string The string to lowercase.
+    /// \param scratch Scratch buffer used to form the resulting string.
+    ///
+    /// \returns the string with the first word lowercased. When the
+    /// first word is an acronym, the string will be returned
+    /// unchanged.
+    StringRef toLowercaseWord(StringRef string, StringScratchSpace &scratch);
+
     /// Sentence-case the given camelCase string by turning the first
     /// letter into an uppercase letter.
     ///
@@ -358,14 +376,6 @@ struct OmissionTypeName {
 /// would produce "ByAppendingString".
 StringRef matchLeadingTypeName(StringRef name, OmissionTypeName typeName);
 
-/// Scratch space used for returning a set of StringRefs.
-class StringScratchSpace {
-  llvm::BumpPtrAllocator Allocator;
-
-public:
-  StringRef copyString(StringRef string);
-};
-
 /// Describes a set of names with an inheritance relationship.
 class InheritedNameSet {
   const InheritedNameSet *Parent;

include/swift/ClangImporter/ClangImporter.h

@@ -259,6 +259,9 @@ class ClangImporter final : public ClangModuleLoader {
   // Print statistics from the Clang AST reader.
   void printStatistics() const override;
 
+  /// Dump Swift lookup tables.
+  void dumpSwiftLookupTables();
+
   /// Given the path of a Clang module, collect the names of all its submodules
   /// and their corresponding visibility. Calling this function does not load the
   /// module.

include/swift/ClangImporter/ClangImporterOptions.h

@@ -73,6 +73,10 @@ class ClangImporterOptions {
   // If true, infer default arguments for nullable pointers (nil) and
   // option sets ([]).
   bool InferDefaultArguments = false;
+
+  /// If true, we should use the Swift name lookup tables rather than
+  /// Clang's name lookup facilities.
+  bool UseSwiftLookupTables = false;
 };
 
 } // end namespace swift

lib/Basic/StringExtras.cpp

@@ -309,12 +309,18 @@ static bool isKeyword(StringRef identifier) {
 static Optional<StringRef> skipTypeSuffix(StringRef typeName) {
   if (typeName.empty()) return None;
 
+  auto lastWord = camel_case::getLastWord(typeName);
+
   // "Type" suffix.
-  if (camel_case::getLastWord(typeName) == "Type" &&
-      typeName.size() > 4) {
+  if (lastWord == "Type" && typeName.size() > 4) {
     return typeName.drop_back(4);
   }
 
+  // "Ref" suffix.
+  if (lastWord == "Ref" && typeName.size() > 3) {
+    return typeName.drop_back(3);
+  }
+
   // \d+D for dimensionality.
   if (typeName.back() == 'D' && typeName.size() > 1) {
     unsigned firstDigit = typeName.size() - 1;
@@ -436,9 +442,10 @@ bool InheritedNameSet::contains(StringRef name) const {
 }
 
 /// Wrapper for camel_case::toLowercaseWord that uses string scratch space.
-static StringRef toLowercaseWord(StringRef string, StringScratchSpace &scratch){
+StringRef camel_case::toLowercaseWord(StringRef string,
+                                      StringScratchSpace &scratch){
   llvm::SmallString<32> scratchStr;
-  StringRef result = camel_case::toLowercaseWord(string, scratchStr);
+  StringRef result = toLowercaseWord(string, scratchStr);
   if (string == result)
     return string;
 

lib/ClangImporter/CMakeLists.txt

@@ -14,6 +14,7 @@ add_swift_library(swiftClangImporter
   ImportDecl.cpp
   ImportMacro.cpp
   ImportType.cpp
+  SwiftLookupTable.cpp
   LINK_LIBRARIES
     swiftAST
 )