Merge pull request #4922 from jckarter/nsvalue-bridging-3.0

[3.0] SE-0139: NSValue bridging

Author: tkremenek

include/swift/AST/ASTContext.h

@@ -514,9 +514,9 @@ class ASTContext {
   ProtocolDecl *getProtocol(KnownProtocolKind kind) const;
 
   /// Determine whether the given nominal type is one of the standard
-  /// library types that is known a priori to be bridged to a
-  /// Foundation.
-  bool isStandardLibraryTypeBridgedInFoundation(NominalTypeDecl *nominal) const;
+  /// library or Cocoa framework types that is known to be bridged by another
+  /// module's overlay, for layering or implementation detail reasons.
+  bool isTypeBridgedInExternalModule(NominalTypeDecl *nominal) const;
 
   /// Get the Objective-C type that a Swift type bridges to, if any.
   /// 

include/swift/AST/Builtins.def

@@ -452,6 +452,9 @@ BUILTIN_MISC_OPERATION(UnsafeGuaranteed, "unsafeGuaranteed", "", Special)
 // unsafeGuaranteedEnd has type (Builtin.Int8) -> ()
 BUILTIN_MISC_OPERATION(UnsafeGuaranteedEnd, "unsafeGuaranteedEnd", "", Special)
 
+// getObjCTypeEncoding has type <T> T.Type -> RawPointer
+BUILTIN_MISC_OPERATION(GetObjCTypeEncoding, "getObjCTypeEncoding", "n", Special)
+
 #undef BUILTIN_MISC_OPERATION
 
 // BUILTIN_TYPE_TRAIT_OPERATION - Compile-time type trait operations.

include/swift/AST/KnownIdentifiers.def

@@ -29,6 +29,8 @@ IDENTIFIER(Any)
 IDENTIFIER(atIndexedSubscript)
 IDENTIFIER_(bridgeToObjectiveC)
 IDENTIFIER_WITH_NAME(code_, "_code")
+IDENTIFIER(CoreGraphics)
+IDENTIFIER(CoreMedia)
 IDENTIFIER(CGFloat)
 IDENTIFIER(CVarArg)
 IDENTIFIER(Darwin)

lib/AST/ASTContext.cpp

@@ -3982,7 +3982,7 @@ ASTContext::getForeignRepresentationInfo(NominalTypeDecl *nominal,
   }
 }
 
-bool ASTContext::isStandardLibraryTypeBridgedInFoundation(
+bool ASTContext::isTypeBridgedInExternalModule(
      NominalTypeDecl *nominal) const {
   return (nominal == getBoolDecl() ||
           nominal == getIntDecl() ||
@@ -3995,8 +3995,18 @@ bool ASTContext::isStandardLibraryTypeBridgedInFoundation(
           nominal == getStringDecl() ||
           nominal == getErrorDecl() ||
           nominal == getAnyHashableDecl() ||
-          // Weird one-off case where CGFloat is bridged to NSNumber.
-          nominal->getName() == Id_CGFloat);
+          // Foundation's overlay depends on the CoreGraphics overlay, but
+          // CoreGraphics value types bridge to Foundation objects such as
+          // NSValue and NSNumber, so to avoid circular dependencies, the
+          // bridging implementations of CG types appear in the Foundation
+          // module.
+          nominal->getParentModule()->getName() == Id_CoreGraphics ||
+          // CoreMedia is a dependency of AVFoundation, but the bridged
+          // NSValue implementations for CMTime, CMTimeRange, and
+          // CMTimeMapping are provided by AVFoundation, and AVFoundation
+          // gets upset if you don't use the NSValue subclasses its factory
+          // methods instantiate.
+          nominal->getParentModule()->getName() == Id_CoreMedia);
 }
 
 Optional<Type>
@@ -4018,7 +4028,7 @@ ASTContext::getBridgedToObjC(const DeclContext *dc, Type type,
   // optimizer will be guaranteed to see the conformance if it exists.
   bool knownBridgedToObjC = false;
   if (auto ntd = type->getAnyNominal())
-    knownBridgedToObjC = isStandardLibraryTypeBridgedInFoundation(ntd);
+    knownBridgedToObjC = isTypeBridgedInExternalModule(ntd);
 
   // TODO: Under id-as-any, container bridging is unconstrained. This check can
   // go away.

lib/AST/Builtins.cpp

@@ -847,6 +847,15 @@ static ValueDecl *getZeroInitializerOperation(ASTContext &Context,
   return builder.build(Id);
 }
 
+static ValueDecl *getGetObjCTypeEncodingOperation(ASTContext &Context,
+                                                  Identifier Id) {
+  // <T> T.Type -> RawPointer
+  GenericSignatureBuilder builder(Context);
+  builder.addParameter(makeMetatype(makeGenericParam()));
+  builder.setResult(makeConcrete(Context.TheRawPointerType));
+  return builder.build(Id);
+}
+
 static ValueDecl *getAddressOfOperation(ASTContext &Context, Identifier Id) {
   // <T> (@inout T) -> RawPointer
   GenericSignatureBuilder builder(Context);
@@ -1626,6 +1635,9 @@ ValueDecl *swift::getBuiltinValueDecl(ASTContext &Context, Identifier Id) {
   case BuiltinValueKind::IntToFPWithOverflow:
     if (Types.size() != 2) return nullptr;
     return getIntToFPWithOverflowOperation(Context, Id, Types[0], Types[1]);
+
+  case BuiltinValueKind::GetObjCTypeEncoding:
+    return getGetObjCTypeEncodingOperation(Context, Id);
   }
 
   llvm_unreachable("bad builtin value!");

lib/IRGen/GenBuiltin.cpp

@@ -22,6 +22,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "swift/AST/Types.h"
 #include "swift/SIL/SILModule.h"
+#include "clang/AST/ASTContext.h"
 
 #include "Explosion.h"
 #include "GenCall.h"
@@ -852,5 +853,18 @@ if (Builtin.ID == BuiltinValueKind::id) { \
     return;
   }
 
+  if (Builtin.ID == BuiltinValueKind::GetObjCTypeEncoding) {
+    args.claimAll();
+    Type valueTy = substitutions[0].getReplacement();
+    // Get the type encoding for the associated clang type.
+    auto clangTy = IGF.IGM.getClangType(valueTy->getCanonicalType());
+    std::string encoding;
+    IGF.IGM.getClangASTContext().getObjCEncodingForType(clangTy, encoding);
+    
+    auto globalString = IGF.IGM.getAddrOfGlobalString(encoding);
+    out.add(globalString);
+    return;
+  }
+  
   llvm_unreachable("IRGen unimplemented for this builtin!");
 }

lib/SIL/DynamicCasts.cpp

@@ -55,10 +55,11 @@ mustBridgeToSwiftValueBox(Module *M, CanType T) {
   if (T->isAnyExistentialType())
     return false;
 
-  // getBridgedToObjC() might return a null-type for bridged foundation types
-  // during compiling the standard library. Exclude this case here.
+  // getBridgedToObjC() might return a null-type for some types
+  // whose bridging implementation is allowed to live elsewhere. Exclude this
+  // case here.
   if (auto N = T->getAnyNominal())
-    if (M->getASTContext().isStandardLibraryTypeBridgedInFoundation(N))
+    if (M->getASTContext().isTypeBridgedInExternalModule(N))
       return false;
 
   auto bridgeTy  = M->getASTContext().getBridgedToObjC(M, T, nullptr);

lib/Sema/TypeCheckProtocol.cpp

@@ -3904,7 +3904,7 @@ void ConformanceChecker::checkConformance() {
   // between an imported Objective-C module and its overlay.
   if (Proto->isSpecificProtocol(KnownProtocolKind::ObjectiveCBridgeable)) {
     if (auto nominal = Adoptee->getAnyNominal()) {
-      if (!TC.Context.isStandardLibraryTypeBridgedInFoundation(nominal)) {
+      if (!TC.Context.isTypeBridgedInExternalModule(nominal)) {
         auto nominalModule = nominal->getParentModule();
         auto conformanceModule = DC->getParentModule();
         if (nominalModule->getName() != conformanceModule->getName()) {

stdlib/private/StdlibUnittestFoundationExtras/CMakeLists.txt

@@ -4,6 +4,6 @@ add_swift_library(swiftStdlibUnittestFoundationExtras ${SWIFT_STDLIB_LIBRARY_BUI
   StdlibUnittestFoundationExtras.swift
   UnavailableFoundationMethodThunks.mm
 
-  SWIFT_MODULE_DEPENDS Foundation
+  SWIFT_MODULE_DEPENDS Foundation StdlibUnittest
   INSTALL_IN_COMPONENT stdlib-experimental)
 

stdlib/private/StdlibUnittestFoundationExtras/StdlibUnittestFoundationExtras.swift

@@ -12,6 +12,7 @@
 
 import ObjectiveC
 import Foundation
+import StdlibUnittest
 
 internal var _temporaryLocaleCurrentLocale: NSLocale? = nil
 
@@ -111,3 +112,20 @@ extension NSDictionary {
       andKeys: keys)
   }
 }
+
+public func expectBridgeToNSValue<T>(_ value: T,
+                                     nsValueInitializer: ((T) -> NSValue)? = nil,
+                                     nsValueGetter: ((NSValue) -> T)? = nil,
+                                     equal: (T, T) -> Bool) {
+  let object = value as AnyObject
+  let nsValue = object as! NSValue
+  if let nsValueInitializer = nsValueInitializer {
+    expectEqual(nsValueInitializer(value), nsValue)
+  }
+  if let nsValueGetter = nsValueGetter {
+    expectTrue(equal(value, nsValueGetter(nsValue)))
+  }
+  expectTrue(equal(value, object as! T))
+
+}
+