Builtin.isbitwisetakable

include/swift/AST/Builtins.def

@@ -419,6 +419,9 @@ BUILTIN_MISC_OPERATION(Strideof, "strideof", "n", Special)
 /// IsPOD has type T.Type -> Bool
 BUILTIN_MISC_OPERATION(IsPOD, "ispod", "n", Special)
 
+/// IsBitwiseTakable has type T.Type -> Bool
+BUILTIN_MISC_OPERATION(IsBitwiseTakable, "isbitwisetakable", "n", Special)
+
 /// IsSameMetatype has type (Any.Type, Any.Type) -> Bool
 BUILTIN_MISC_OPERATION(IsSameMetatype, "is_same_metatype", "n", Special)
 

include/swift/Serialization/ModuleFormat.h

@@ -55,7 +55,7 @@ const uint16_t VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t VERSION_MINOR = 437; // Last change: remove pinning
+const uint16_t VERSION_MINOR = 438; // Last change: add isbitwisetakable
 
 using DeclIDField = BCFixed<31>;
 

lib/AST/Builtins.cpp

@@ -736,6 +736,13 @@ static ValueDecl *getIsPODOperation(ASTContext &Context, Identifier Id) {
   return builder.build(Id);
 }
 
+static ValueDecl *getIsBitwiseTakable(ASTContext &Context, Identifier Id) {
+  BuiltinGenericSignatureBuilder builder(Context);
+  builder.addParameter(makeMetatype(makeGenericParam()));
+  builder.setResult(makeConcrete(BuiltinIntegerType::get(1,Context)));
+  return builder.build(Id);
+}
+
 static ValueDecl *getIsOptionalOperation(ASTContext &Context, Identifier Id) {
   BuiltinGenericSignatureBuilder builder(Context);
   builder.addParameter(makeMetatype(makeGenericParam()));
@@ -1736,6 +1743,9 @@ ValueDecl *swift::getBuiltinValueDecl(ASTContext &Context, Identifier Id) {
   case BuiltinValueKind::IsPOD:
     return getIsPODOperation(Context, Id);
 
+  case BuiltinValueKind::IsBitwiseTakable:
+    return getIsBitwiseTakable(Context, Id);
+
   case BuiltinValueKind::IsOptionalType:
     return getIsOptionalOperation(Context, Id);
 

lib/IRGen/FixedTypeInfo.h

@@ -91,6 +91,7 @@ class FixedTypeInfo : public TypeInfo {
   llvm::Value *getAlignmentMask(IRGenFunction &IGF, SILType T) const override;
   llvm::Value *getStride(IRGenFunction &IGF, SILType T) const override;
   llvm::Value *getIsPOD(IRGenFunction &IGF, SILType T) const override;
+  llvm::Value *getIsBitwiseTakable(IRGenFunction &IGF, SILType T) const override;
   llvm::Value *isDynamicallyPackedInline(IRGenFunction &IGF,
                                          SILType T) const override;
 

lib/IRGen/GenBuiltin.cpp

@@ -178,6 +178,13 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
     return;
   }
 
+  if (Builtin.ID == BuiltinValueKind::IsBitwiseTakable) {
+    (void)args.claimAll();
+    auto valueTy = getLoweredTypeAndTypeInfo(IGF.IGM,
+                                             substitutions.getReplacementTypes()[0]);
+    out.add(valueTy.second.getIsBitwiseTakable(IGF, valueTy.first));
+    return;
+  }
 
   // addressof expects an lvalue argument.
   if (Builtin.ID == BuiltinValueKind::AddressOf) {

lib/IRGen/GenType.cpp

@@ -220,6 +220,10 @@ llvm::Value *FixedTypeInfo::getIsPOD(IRGenFunction &IGF, SILType T) const {
   return llvm::ConstantInt::get(IGF.IGM.Int1Ty,
                                 isPOD(ResilienceExpansion::Maximal) == IsPOD);
 }
+llvm::Value *FixedTypeInfo::getIsBitwiseTakable(IRGenFunction &IGF, SILType T) const {
+  return llvm::ConstantInt::get(IGF.IGM.Int1Ty,
+                                isBitwiseTakable(ResilienceExpansion::Maximal) == IsBitwiseTakable);
+}
 llvm::Constant *FixedTypeInfo::getStaticStride(IRGenModule &IGM) const {
   return asSizeConstant(IGM, getFixedStride());
 }

lib/IRGen/NonFixedTypeInfo.h

@@ -110,6 +110,10 @@ class WitnessSizedTypeInfo : public IndirectTypeInfo<Impl, TypeInfo> {
     return emitLoadOfIsPOD(IGF, T);
   }
 
+  llvm::Value *getIsBitwiseTakable(IRGenFunction &IGF, SILType T) const override {
+    return emitLoadOfIsBitwiseTakable(IGF, T);
+  }
+
   llvm::Value *isDynamicallyPackedInline(IRGenFunction &IGF,
                                          SILType T) const override {
     return emitLoadOfIsInline(IGF, T);

lib/IRGen/TypeInfo.h

@@ -287,6 +287,7 @@ class TypeInfo {
   virtual llvm::Value *getAlignmentMask(IRGenFunction &IGF, SILType T) const = 0;
   virtual llvm::Value *getStride(IRGenFunction &IGF, SILType T) const = 0;
   virtual llvm::Value *getIsPOD(IRGenFunction &IGF, SILType T) const = 0;
+  virtual llvm::Value *getIsBitwiseTakable(IRGenFunction &IGF, SILType T) const = 0;
   virtual llvm::Value *isDynamicallyPackedInline(IRGenFunction &IGF,
                                                  SILType T) const = 0;
 

lib/SIL/SILOwnershipVerifier.cpp

@@ -1234,6 +1234,7 @@ CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, IntToFPWithOverflow)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, IntToPtr)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, IsOptionalType)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, IsPOD)
+CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, IsBitwiseTakable)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, IsSameMetatype)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, LShr)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, MustBeLive, Mul)

lib/SIL/ValueOwnershipKindClassifier.cpp

@@ -471,6 +471,7 @@ CONSTANT_OWNERSHIP_BUILTIN(Trivial, Sizeof)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, Strideof)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, StringObjectOr)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, IsPOD)
+CONSTANT_OWNERSHIP_BUILTIN(Trivial, IsBitwiseTakable)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, IsSameMetatype)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, Alignof)
 CONSTANT_OWNERSHIP_BUILTIN(Trivial, AllocRaw)

stdlib/public/core/Builtin.swift

@@ -672,6 +672,14 @@ func _isPOD<T>(_ type: T.Type) -> Bool {
   return Bool(Builtin.ispod(type))
 }
 
+/// Returns `true` if type is a bitwise takable. A bitwise takable type can
+/// just be moved to a different address in memory.
+@_transparent
+public // @testable
+func _isBitwiseTakable<T>(_ type: T.Type) -> Bool {
+  return Bool(Builtin.isbitwisetakable(type))
+}
+
 /// Returns `true` if type is nominally an Optional type.
 @_transparent
 public // @testable

test/IRGen/builtins.swift

@@ -692,6 +692,31 @@ func ispod_test() {
   var f = Builtin.ispod(Builtin.NativeObject.self)
 }
 
+// CHECK-LABEL: define {{.*}} @{{.*}}generic_isbitwisetakable_test
+func generic_isbitwisetakable_test<T>(_: T) {
+  // CHECK:      [[T0:%.*]] = getelementptr inbounds i8*, i8** [[T:%.*]], i32 9
+  // CHECK-NEXT: [[T1:%.*]] = load i8*, i8** [[T0]]
+  // CHECK-NEXT: [[FLAGS:%.*]] = ptrtoint i8* [[T1]] to i64
+  // CHECK-NEXT: [[ISNOTBITWISETAKABLE:%.*]] = and i64 [[FLAGS]], 1048576
+  // CHECK-NEXT: [[ISBITWISETAKABLE:%.*]] = icmp eq i64 [[ISNOTBITWISETAKABLE]], 0
+  // CHECK-NEXT: store i1 [[ISBITWISETAKABLE]], i1* [[S:%.*]]
+  var s = Builtin.isbitwisetakable(T.self)
+}
+
+// CHECK-LABEL: define {{.*}} @{{.*}}isbitwisetakable_test
+func isbitwisetakable_test() {
+  // CHECK: store i1 true, i1*
+  // CHECK: store i1 true, i1*
+  // CHECK: store i1 true, i1*
+  // CHECK: store i1 true, i1*
+  // CHECK: store i1 false, i1*
+  var t1 = Builtin.isbitwisetakable(Int.self)
+  var t2 = Builtin.isbitwisetakable(C.self)
+  var t3 = Builtin.isbitwisetakable(Abc.self)
+  var t4 = Builtin.isbitwisetakable(Empty.self)
+  var f = Builtin.isbitwisetakable(W.self)
+}
+
 // CHECK-LABEL: define {{.*}} @{{.*}}is_same_metatype
 func is_same_metatype_test(_ t1: Any.Type, _ t2: Any.Type) {
   // CHECK: [[MT1_AS_PTR:%.*]] = bitcast %swift.type* %0 to i8*

test/stdlib/Builtins.swift

@@ -29,6 +29,10 @@ var tests = TestSuite("Builtins")
 
 class X {}
 
+struct W {
+    weak var weakX: X?
+}
+
 tests.test("_isUnique/NativeObject") {
   var a: Builtin.NativeObject = Builtin.castToNativeObject(X())
   expectNotEqual(false, _isUnique_native(&a))
@@ -273,6 +277,13 @@ tests.test("_isPOD") {
   expectFalse(_isPOD(P.self))
 }
 
+tests.test("_isBitwiseTakable") {
+  expectTrue(_isBitwiseTakable(Int.self))
+  expectTrue(_isBitwiseTakable(X.self))
+  expectTrue(_isBitwiseTakable(P.self))
+  expectFalse(_isBitwiseTakable(W.self))
+}
+
 tests.test("_isOptional") {
   expectTrue(_isOptional(Optional<Int>.self))
   expectTrue(_isOptional(Optional<X>.self))