[SourceKit] Add a new request to translate from Objc names to Swift names and vice versa.

Extensive cross-language tooling support needs to bridge decl names between two different languages more freely. This SourceKit request is designed to translate Objc names to Swift names and vice versa. Working similarly to cursor-info requisition, the name translation request requires a Swift reference to a Swift/Clang decl, and the preferred name to translate from, and language kind that the given name belongs to. If the translation succeeds, SourceKit service responds with the corresponding name than belongs to the other kind of language.

Newly introduced keys:

“key.namekind": “source.lang.name.kind.objc” | "source.lang.name.kind.swift"
“key.basename”: “name"
“key.argnames”: [“name"]
“key.selectorpieces”: [“name[:]"]

This commit only implements translation from Objc to Swift.

Author: nkcsgexi

include/swift/ClangImporter/ClangImporter.h

@@ -38,10 +38,10 @@ namespace clang {
   class Sema;
   class TargetInfo;
   class VisibleDeclConsumer;
+  class DeclarationName;
 }
 
 namespace swift {
-
 class ASTContext;
 class ClangImporterOptions;
 class ClangModuleUnit;
@@ -267,13 +267,13 @@ class ClangImporter final : public ClangModuleLoader {
   void getMangledName(raw_ostream &os, const clang::NamedDecl *clangDecl) const;
 
   using ClangModuleLoader::addDependency;
-  
+
   // 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.
   /// Calling this function does not load the module.
   void collectSubModuleNames(
@@ -282,6 +282,9 @@ class ClangImporter final : public ClangModuleLoader {
 
   /// Given a Clang module, decide whether this module is imported already.
   static bool isModuleImported(const clang::Module *M);
+
+  DeclName importName(const clang::NamedDecl *D,
+                      clang::DeclarationName givenName);
 };
 
 ImportDecl *createImportDecl(ASTContext &Ctx, DeclContext *DC, ClangNode ClangN,

lib/ClangImporter/ClangImporter.cpp

@@ -2889,3 +2889,10 @@ void ClangImporter::Implementation::dumpSwiftLookupTables() {
   llvm::errs() << "<<Bridging header lookup table>>\n";
   BridgingHeaderLookupTable->dump();
 }
+
+DeclName ClangImporter::
+importName(const clang::NamedDecl *D,
+           clang::DeclarationName preferredName) {
+  return Impl.importFullName(D, Impl.CurrentVersion, preferredName).
+    getDeclName();
+}

lib/ClangImporter/ImportName.cpp

@@ -1073,7 +1073,8 @@ static bool suppressFactoryMethodAsInit(const clang::ObjCMethodDecl *method,
 }
 
 ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
-                                          ImportNameVersion version) {
+                                          ImportNameVersion version,
+                                          clang::DeclarationName givenName) {
   ImportedName result;
 
   /// Whether we want a Swift 3 or later name
@@ -1112,7 +1113,7 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
     SmallVector<const clang::ObjCMethodDecl *, 4> overriddenMethods;
     method->getOverriddenMethods(overriddenMethods);
     for (auto overridden : overriddenMethods) {
-      const auto overriddenName = importName(overridden, version);
+      const auto overriddenName = importName(overridden, version, givenName);
       if (overriddenName.getDeclName())
         overriddenNames.push_back({overridden, overriddenName});
     }
@@ -1144,7 +1145,8 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
         if (!knownProperties.insert(overriddenProperty).second)
           continue;
 
-        const auto overriddenName = importName(overriddenProperty, version);
+        const auto overriddenName = importName(overriddenProperty, version,
+                                               givenName);
         if (overriddenName.getDeclName())
           overriddenNames.push_back({overriddenProperty, overriddenName});
       }
@@ -1293,6 +1295,12 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
     // Map the identifier.
     baseName = D->getDeclName().getAsIdentifierInfo()->getName();
 
+    if (givenName) {
+      if (!givenName.isIdentifier())
+        return ImportedName();
+      baseName = givenName.getAsIdentifierInfo()->getName();
+    }
+
     // For Objective-C BOOL properties, use the name of the getter
     // which, conventionally, has an "is" prefix.
     if (swift3OrLaterName) {
@@ -1322,6 +1330,24 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
 
     // Map the Objective-C selector directly.
     auto selector = D->getDeclName().getObjCSelector();
+
+    // Respect the given name.
+    if (givenName) {
+      switch (givenName.getNameKind()) {
+      case clang::DeclarationName::ObjCOneArgSelector:
+      case clang::DeclarationName::ObjCMultiArgSelector:
+      case clang::DeclarationName::ObjCZeroArgSelector:
+
+        // Make sure the given name has the right count of arguments.
+        if (selector.getNumArgs() != givenName.getObjCSelector().getNumArgs())
+          return ImportedName();
+        selector = givenName.getObjCSelector();
+        break;
+      default:
+        return ImportedName();
+      }
+    }
+
     baseName = selector.getNameForSlot(0);
 
     // We don't support methods with empty first selector pieces.
@@ -1435,9 +1461,24 @@ ImportedName NameImporter::importNameImpl(const clang::NamedDecl *D,
     auto enumInfo = getEnumInfo(enumDecl);
 
     StringRef removePrefix = enumInfo.getConstantNamePrefix();
-    if (!removePrefix.empty() && baseName.startswith(removePrefix)) {
-      baseName = baseName.substr(removePrefix.size());
-      strippedPrefix = true;
+    if (!removePrefix.empty()) {
+      if (baseName.startswith(removePrefix)) {
+        baseName = baseName.substr(removePrefix.size());
+        strippedPrefix = true;
+      } else if (givenName) {
+        // Calculate the new prefix.
+        // What if the preferred name causes longer prefix?
+        StringRef subPrefix = [](StringRef LHS, StringRef RHS) {
+          if(LHS.size() > RHS.size())
+            std::swap(LHS, RHS) ;
+          return StringRef(LHS.data(), std::mismatch(LHS.begin(), LHS.end(),
+            RHS.begin()).first - LHS.begin());
+        }(removePrefix, baseName);
+        if (!subPrefix.empty()) {
+          baseName = baseName.substr(subPrefix.size());
+          strippedPrefix = true;
+        }
+      }
     }
   }
 
@@ -1611,15 +1652,17 @@ NameImporter::importMacroName(const clang::IdentifierInfo *clangIdentifier,
 }
 
 ImportedName NameImporter::importName(const clang::NamedDecl *decl,
-                                      ImportNameVersion version) {
+                                      ImportNameVersion version,
+                                      clang::DeclarationName givenName) {
   CacheKeyType key(decl, version);
-  if (importNameCache.count(key)) {
+  if (importNameCache.count(key) && !givenName) {
     ++ImportNameNumCacheHits;
     return importNameCache[key];
   }
   ++ImportNameNumCacheMisses;
-  auto res = importNameImpl(decl, version);
+  auto res = importNameImpl(decl, version, givenName);
   res.setVersion(version);
-  importNameCache[key] = res;
+  if (!givenName)
+    importNameCache[key] = res;
   return res;
 }

lib/ClangImporter/ImportName.h

@@ -212,7 +212,7 @@ class ImportedName {
     case ImportedAccessorKind::SubscriptSetter:
       return true;
     }
-    
+
     llvm_unreachable("Invalid ImportedAccessorKind.");
   }
 };
@@ -250,7 +250,9 @@ class NameImporter {
 
   /// Determine the Swift name for a Clang decl
   ImportedName importName(const clang::NamedDecl *decl,
-                          ImportNameVersion version);
+                          ImportNameVersion version,
+                          clang::DeclarationName preferredName =
+                            clang::DeclarationName());
 
   /// Imports the name of the given Clang macro into Swift.
   Identifier importMacroName(const clang::IdentifierInfo *clangIdentifier,
@@ -313,7 +315,8 @@ class NameImporter {
                                                   ImportNameVersion version);
 
   ImportedName importNameImpl(const clang::NamedDecl *,
-                              ImportNameVersion version);
+                              ImportNameVersion version,
+                              clang::DeclarationName);
 };
 
 }

lib/ClangImporter/ImporterImpl.h

@@ -607,8 +607,10 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   ///
   /// \param D The Clang declaration whose name should be imported.
   importer::ImportedName importFullName(const clang::NamedDecl *D,
-                                        Version version) {
-    return getNameImporter().importName(D, version);
+                                        Version version,
+                                        clang::DeclarationName givenName =
+                                          clang::DeclarationName()) {
+    return getNameImporter().importName(D, version, givenName);
   }
 
   /// Print an imported name as a string suitable for the swift_name attribute,

test/SourceKit/NameTranslation/Inputs/mock-sdk/Foo.framework/Frameworks/FooSub.framework/Headers/FooSub.h

@@ -0,0 +1,15 @@
+#if !defined(__FOOSUB_H__)
+#define __FOOSUB_H__ 1
+
+int fooSubFunc1(int a);
+
+enum FooSubEnum1 {
+  FooSubEnum1X,
+  FooSubEnum1Y
+};
+
+enum {
+  FooSubUnnamedEnumeratorA1
+};
+
+#endif /* ! __FOOSUB_H__ */