[WIP] Teach SourceKit name translation request to translate Swift names to ObjC ones (by using PrintAsObjC).

include/swift/AST/Decl.h

@@ -4116,11 +4116,13 @@ class AbstractStorageDecl : public ValueDecl {
 
   /// Given that this is an Objective-C property or subscript declaration,
   /// produce its getter selector.
-  ObjCSelector getObjCGetterSelector(LazyResolver *resolver = nullptr) const;
+  ObjCSelector getObjCGetterSelector(LazyResolver *resolver = nullptr,
+                                Identifier preferredName = Identifier()) const;
 
   /// Given that this is an Objective-C property or subscript declaration,
   /// produce its setter selector.
-  ObjCSelector getObjCSetterSelector(LazyResolver *resolver = nullptr) const;
+  ObjCSelector getObjCSetterSelector(LazyResolver *resolver = nullptr,
+                                Identifier preferredName = Identifier()) const;
 
   AbstractStorageDecl *getOverriddenDecl() const {
     return OverriddenDecl;
@@ -4844,7 +4846,8 @@ class AbstractFunctionDecl : public ValueDecl, public DeclContext {
   const CaptureInfo &getCaptureInfo() const { return Captures; }
 
   /// Retrieve the Objective-C selector that names this method.
-  ObjCSelector getObjCSelector(LazyResolver *resolver = nullptr) const;
+  ObjCSelector getObjCSelector(LazyResolver *resolver = nullptr,
+                               DeclName preferredName = DeclName()) const;
 
   /// Determine whether the given method would produce an Objective-C
   /// instance method.

include/swift/AST/Identifier.h

@@ -433,6 +433,12 @@ class ObjCSelector {
   /// pieces.
   ObjCSelector(ASTContext &ctx, unsigned numArgs, ArrayRef<Identifier> pieces);
 
+  /// Construct an invalid ObjCSelector.
+  ObjCSelector() : Storage() {};
+
+  /// Convert to true if the decl name is valid.
+  explicit operator bool() const { return (bool)Storage; }
+
   /// Determine the number of arguments in the selector.
   ///
   /// When this is zero, the number of selector pieces will be one. Otherwise,

include/swift/PrintAsObjC/PrintAsObjC.h

@@ -15,16 +15,26 @@
 
 #include "swift/Basic/LLVM.h"
 #include "swift/AST/AttrKind.h"
+#include "swift/AST/Identifier.h"
 
 namespace swift {
   class ModuleDecl;
+  class ValueDecl;
 
   /// Print the Objective-C-compatible declarations in a module as a Clang
   /// header.
   ///
   /// Returns true on error.
   bool printAsObjC(raw_ostream &out, ModuleDecl *M, StringRef bridgingHeader,
                    Accessibility minRequiredAccess);
+
+  /// Get the name for a value decl D if D is exported to ObjC, PreferredName is
+  /// specified to perform what-if analysis, shadowing D's original name during
+  /// computation.
+  ///
+  /// Returns a pair of Identifier and ObjCSelector, only one of which is valid.
+  std::pair<Identifier, ObjCSelector> getObjCNameForSwiftDecl(const ValueDecl *VD,
+    DeclName PreferredName);
 }
 
 #endif

lib/AST/Decl.cpp

@@ -3406,7 +3406,7 @@ void AbstractStorageDecl::setInvalidBracesRange(SourceRange BracesRange) {
 }
 
 ObjCSelector AbstractStorageDecl::getObjCGetterSelector(
-               LazyResolver *resolver) const {
+               LazyResolver *resolver, Identifier preferredName) const {
   // If the getter has an @objc attribute with a name, use that.
   if (auto getter = getGetter()) {
     if (auto objcAttr = getter->getAttrs().getAttribute<ObjCAttr>()) {
@@ -3430,11 +3430,16 @@ ObjCSelector AbstractStorageDecl::getObjCGetterSelector(
 
   // The getter selector is the property name itself.
   auto var = cast<VarDecl>(this);
-  return VarDecl::getDefaultObjCGetterSelector(ctx, var->getObjCPropertyName());
+  auto name = var->getObjCPropertyName();
+
+  // Use preferred name is specified.
+  if (!preferredName.empty())
+    name = preferredName;
+  return VarDecl::getDefaultObjCGetterSelector(ctx, name);
 }
 
 ObjCSelector AbstractStorageDecl::getObjCSetterSelector(
-               LazyResolver *resolver) const {
+               LazyResolver *resolver, Identifier preferredName) const {
   // If the setter has an @objc attribute with a name, use that.
   auto setter = getSetter();
   auto objcAttr = setter ? setter->getAttrs().getAttribute<ObjCAttr>()
@@ -3464,9 +3469,10 @@ ObjCSelector AbstractStorageDecl::getObjCSetterSelector(
   // The setter selector for, e.g., 'fooBar' is 'setFooBar:', with the
   // property name capitalized and preceded by 'set'.
   auto var = cast<VarDecl>(this);
-  auto result = VarDecl::getDefaultObjCSetterSelector(
-                  ctx, 
-                  var->getObjCPropertyName());
+  Identifier Name = var->getObjCPropertyName();
+  if (!preferredName.empty())
+    Name = preferredName;
+  auto result = VarDecl::getDefaultObjCSetterSelector(ctx, Name);
 
   // Cache the result, so we don't perform string manipulation again.
   if (objcAttr)
@@ -4320,7 +4326,7 @@ SourceRange AbstractFunctionDecl::getSignatureSourceRange() const {
 }
 
 ObjCSelector AbstractFunctionDecl::getObjCSelector(
-               LazyResolver *resolver) const {
+               LazyResolver *resolver, DeclName preferredName) const {
   // If there is an @objc attribute with a name, use that name.
   auto objc = getAttrs().getAttribute<ObjCAttr>();
   if (objc) {
@@ -4329,15 +4335,27 @@ ObjCSelector AbstractFunctionDecl::getObjCSelector(
   }
 
   auto &ctx = getASTContext();
+  auto baseName = getName();
   auto argNames = getFullName().getArgumentNames();
 
+  // Use the preferred name if specified
+  if (preferredName) {
+    // Return invalid selector if argument count doesn't match.
+    if (argNames.size() != preferredName.getArgumentNames().size()) {
+      return ObjCSelector();
+    }
+    baseName = preferredName.getBaseName();
+    argNames = preferredName.getArgumentNames();
+  }
+
   auto func = dyn_cast<FuncDecl>(this);
   if (func) {
     // For a getter or setter, go through the variable or subscript decl.
     if (func->isGetterOrSetter()) {
       auto asd = cast<AbstractStorageDecl>(func->getAccessorStorageDecl());
-      return func->isGetter() ? asd->getObjCGetterSelector(resolver)
-                              : asd->getObjCSetterSelector(resolver);
+      return func->isGetter() ?
+        asd->getObjCGetterSelector(resolver, baseName) :
+        asd->getObjCSetterSelector(resolver, baseName);
     }
   }
 
@@ -4373,12 +4391,12 @@ ObjCSelector AbstractFunctionDecl::getObjCSelector(
 
   // If we have no arguments, it's a nullary selector.
   if (numSelectorPieces == 0) {
-    return ObjCSelector(ctx, 0, getName());
+    return ObjCSelector(ctx, 0, baseName);
   }
 
  // If it's a unary selector with no name for the first argument, we're done.
   if (numSelectorPieces == 1 && argNames.size() == 1 && argNames[0].empty()) {
-    return ObjCSelector(ctx, 1, getName());
+    return ObjCSelector(ctx, 1, baseName);
   }
 
   /// Collect the selector pieces.
@@ -4403,7 +4421,7 @@ ObjCSelector AbstractFunctionDecl::getObjCSelector(
 
     // For the first selector piece, attach either the first parameter
     // or "AndReturnError" to the base name, if appropriate.
-    auto firstPiece = getName();
+    auto firstPiece = baseName;
     llvm::SmallString<32> scratch;
     scratch += firstPiece.str();
     if (errorConvention && piece == errorConvention->getErrorParameterIndex()) {

lib/PrintAsObjC/PrintAsObjC.cpp

@@ -2633,3 +2633,34 @@ bool swift::printAsObjC(llvm::raw_ostream &os, ModuleDecl *M,
   llvm::PrettyStackTraceString trace("While generating Objective-C header");
   return ModuleWriter(*M, bridgingHeader, minRequiredAccess).writeToStream(os);
 }
+
+std::pair<Identifier, ObjCSelector> swift::
+getObjCNameForSwiftDecl(const ValueDecl *VD, DeclName PreferredName){
+  ASTContext &Ctx = VD->getASTContext();
+  LazyResolver *Resolver = Ctx.getLazyResolver();
+  if (auto *FD = dyn_cast<AbstractFunctionDecl>(VD)) {
+    return {Identifier(), FD->getObjCSelector(Resolver, PreferredName)};
+  } else if (auto *VAD = dyn_cast<VarDecl>(VD)) {
+    if (PreferredName)
+      return {PreferredName.getBaseName(), ObjCSelector()};
+    return {VAD->getObjCPropertyName(), ObjCSelector()};
+  } else if (auto *SD = dyn_cast<SubscriptDecl>(VD)) {
+    return getObjCNameForSwiftDecl(SD->getGetter(), PreferredName);
+  } else if (auto *EL = dyn_cast<EnumElementDecl>(VD)) {
+    EnumDecl* ED = EL->getDeclContext()->getAsEnumOrEnumExtensionContext();
+    SmallString<64> Buffer;
+    {
+      llvm::raw_svector_ostream OS(Buffer);
+      OS << getNameForObjC(ED).str();
+      SmallString<64> Scratch;
+      OS << camel_case::toSentencecase(PreferredName.getBaseName().str(),
+                                       Scratch);
+    }
+    return {Ctx.getIdentifier(Buffer.str()), ObjCSelector()};
+  } else {
+    auto Name = getNameForObjC(VD, CustomNamesOnly);
+    if (!Name.empty())
+      return {Ctx.getIdentifier(Name), ObjCSelector()};
+    return {PreferredName.getBaseName(), ObjCSelector()};
+  }
+}

test/SourceKit/NameTranslation/swiftnames.swift

@@ -0,0 +1,83 @@
+class C1 : NSObject {
+  func foo(a : Int, b: Int, c : Int) {}
+  func foo1(a : Int, _: Int, c : Int) {}
+  func foo2(_ : Int, _: Int, c : Int) {}
+  func foo3() {}
+  init(a : Int, b :Int) {}
+  init(_ : Int) {}
+}
+func takeC1(a : Int, b: Int, c :Int) -> C1 {
+  let C1Ins = C1(a: a, b: b)
+  C1Ins.foo(a: a, b: b, c: c)
+  C1Ins.foo1(a: a, b, c: c)
+  C1Ins.foo2(a, b, c: c)
+  C1Ins.foo3()
+  let C1Ins2 = C1(a)
+  return C1Ins2
+}
+
+@objc public enum CommonFix : Int {
+  case A1
+  case B1
+  case C1
+}
+
+func takeCommonFix(_ f: CommonFix) -> Int {
+  switch(f) {
+  case .A1: break
+  case .B1: break
+  case .C1: break
+    return 1
+  }
+  return 0
+}
+
+@objc public enum CustomError: Int, Error {
+    case a1, b1
+}
+
+func takeError(_ e : CustomError) {
+  switch(e) {
+  case .a1: break
+  case .b1: break
+    return
+  }
+}
+
+// REQUIRES: objc_interop
+// RUN: %sourcekitd-test -req=translate -swift-name "foo(a:b:c:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK1 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo(a1:b1:c1:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK2 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo(_:b1:c1:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK3 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo1(_:_:c2:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK4 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo1(_:_:_:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK5 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo2(a:b:c:)" -pos=12:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK6 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo2(_:_:_:)" -pos=12:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK7 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo1()" -pos=14:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK8 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo1(a:b:c:)" -pos=14:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
+// RUN: %sourcekitd-test -req=translate -swift-name "C11" -pos=1:8 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK9 %s
+
+// RUN: %sourcekitd-test -req=translate -swift-name "init(a1:b2:)" -pos=10:16 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK10 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "init(_:_:)" -pos=10:16 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK11 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo(a1:_:)" -pos=10:16 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK12 %s
+
+// RUN: %sourcekitd-test -req=translate -swift-name "A2" -pos=27:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK13 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "a2" -pos=27:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK13 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "a2" -pos=41:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK14 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "A2" -pos=41:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK14 %s
+
+// CHECK-NONE: <empty name translation info>
+// CHECK1: fooWithA:b:c:
+// CHECK2: fooWithA1:b1:c1:
+// CHECK3: foo:b1:c1:
+// CHECK4: foo1::c2:
+// CHECK5: foo1:::
+// CHECK6: foo2WithA:b:c:
+// CHECK7: foo2:::
+// CHECK8: foo1
+// CHECK9: C11
+
+// CHECK10: initWithA1:b2:
+// CHECK11: init::
+// CHECK12: fooWithA1::
+// CHECK13: CommonFixA2
+// CHECK14: CustomErrorA2

tools/SourceKit/lib/SwiftLang/CMakeLists.txt

@@ -10,7 +10,7 @@ add_sourcekit_library(SourceKitSwiftLang
   SwiftSourceDocInfo.cpp
   DEPENDS SourceKitCore swiftDriver swiftFrontend swiftClangImporter swiftIndex swiftIDE
           swiftAST swiftMarkup swiftParse swiftSIL swiftSILGen swiftSILOptimizer
-          swiftIRGen swiftSema swiftBasic swiftSerialization
+          swiftIRGen swiftSema swiftBasic swiftSerialization swiftPrintAsObjC
           swiftOption libcmark_static
     # Clang dependencies.
       clangIndex

tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp

@@ -27,6 +27,7 @@
 #include "swift/IDE/ModuleInterfacePrinting.h"
 #include "swift/IDE/Utils.h"
 #include "swift/Markup/XMLUtils.h"
+#include "swift/PrintAsObjC/PrintAsObjC.h"
 #include "swift/Sema/IDETypeChecking.h"
 
 #include "clang/AST/ASTContext.h"
@@ -877,14 +878,47 @@ getClangDeclarationName(clang::ASTContext &Ctx, NameTranslatingInfo &Info) {
   }
 }
 
+static DeclName
+getSwiftDeclName(ASTContext &Ctx, NameTranslatingInfo &Info) {
+  assert(SwiftLangSupport::getNameKindForUID(Info.NameKind) == NameKind::Swift);
+  std::vector<Identifier> Args(Info.ArgNames.size(), Identifier());
+  std::transform(Info.ArgNames.begin(), Info.ArgNames.end(), Args.begin(),
+                 [&](StringRef T) { return Ctx.getIdentifier(T); });
+  return DeclName(Ctx, Ctx.getIdentifier(Info.BaseName),
+                  llvm::makeArrayRef(Args));
+}
+
 /// Returns true for failure to resolve.
 static bool passNameInfoForDecl(const ValueDecl *VD, NameTranslatingInfo &Info,
                     std::function<void(const NameTranslatingInfo &)> Receiver) {
   switch (SwiftLangSupport::getNameKindForUID(Info.NameKind)) {
   case NameKind::Swift: {
-
-    // FIXME: Implement the swift to objc name translation.
-    return true;
+    NameTranslatingInfo Result;
+    auto &Ctx = VD->getDeclContext()->getASTContext();
+    auto ResultPair = getObjCNameForSwiftDecl(VD, getSwiftDeclName(Ctx, Info));
+    Identifier Name = ResultPair.first;
+    if (!Name.empty()) {
+      Result.NameKind = SwiftLangSupport::getUIDForNameKind(NameKind::ObjC);
+      Result.BaseName = Name.str();
+    } else if (ObjCSelector Selector = ResultPair.second) {
+      Result.NameKind = SwiftLangSupport::getUIDForNameKind(NameKind::ObjC);
+      SmallString<64> Buffer;
+      StringRef Total = Selector.getString(Buffer);
+      SmallVector<StringRef, 4> Pieces;
+      Total.split(Pieces, ":");
+      if (Selector.getNumArgs()) {
+        assert(Pieces.back().empty());
+        Pieces.pop_back();
+        std::transform(Pieces.begin(), Pieces.end(), Pieces.begin(),
+          [](StringRef P) { return StringRef(P.data(), P.size() + 1); });
+      }
+      Result.ArgNames = llvm::makeArrayRef(Pieces);
+    } else {
+      Receiver(Result);
+      return true;
+    }
+    Receiver(Result);
+    return false;
   }
   case NameKind::ObjC: {
     ClangImporter *Importer = static_cast<ClangImporter *>(VD->getDeclContext()->

tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp

@@ -593,7 +593,7 @@ static int handleTestInvocation(ArrayRef<const char *> Args,
       } else {
         BaseName = Text.substr(0, ArgStart);
         auto ArgEnd = Text.find_last_of(')');
-        if (ArgEnd != StringRef::npos) {
+        if (ArgEnd == StringRef::npos) {
           llvm::errs() << "Swift name is malformed.\n";
           return 1;
         }
@@ -1160,9 +1160,6 @@ static void printNameTranslationInfo(sourcekitd_variant_t Info,
   }
   for (auto S : Selectors) {
     OS << S;
-    if (S != Selectors.back()) {
-      OS << ":";
-    }
   }
   OS << '\n';
 }

tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp

@@ -801,7 +801,10 @@ handleSemanticRequest(RequestDict Req,
     }
     Input.ArgNames.resize(ArgParts.size() + Selectors.size());
     std::transform(ArgParts.begin(), ArgParts.end(), Input.ArgNames.begin(),
-                   [](const char *C) { return StringRef(C); });
+      [](const char *C) {
+        StringRef Original(C);
+        return Original == "_" ? StringRef() : Original;
+      });
     std::transform(Selectors.begin(), Selectors.end(), Input.ArgNames.begin(),
                    [](const char *C) { return StringRef(C); });
     return Lang.getNameInfo(*SourceFile, Offset, Input, Args,