Fixes for stored property initializers

lib/AST/Decl.cpp

@@ -8682,10 +8682,23 @@ ActorIsolation swift::getActorIsolationOfContext(DeclContext *dc) {
   if (auto *vd = dyn_cast_or_null<ValueDecl>(dc->getAsDecl()))
     return getActorIsolation(vd);
 
+  // In the context of the initializing or default-value expression of a
+  // stored property, the isolation varies between global and type members:
+  //   - For a static stored property, the isolation matches the VarDecl.
+  //   - For a field of a nominal type, the expression is not isolated.
+  // Without this distinction, a nominal can have non-async initializers
+  // with various kinds of isolation, so an impossible constraint can be
+  // created. See SE-0327 for details.
   if (auto *init = dyn_cast<PatternBindingInitializer>(dc)) {
-    if (auto *var = init->getBinding()->getAnchoringVarDecl(
-            init->getBindingIndex()))
+    if (auto *var =
+          init->getBinding()->getAnchoringVarDecl(init->getBindingIndex())) {
+
+      if (var->isInstanceMember() &&
+          !var->getAttrs().hasAttribute<LazyAttr>())
+        return ActorIsolation::forUnspecified();
+
       return getActorIsolation(var);
+    }
   }
 
   if (auto *closure = dyn_cast<AbstractClosureExpr>(dc)) {

lib/SILGen/SILGenFunction.h

@@ -704,7 +704,9 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// Generate an ObjC-compatible destructor (-dealloc).
   void emitObjCDestructor(SILDeclRef dtor);
 
-  ManagedValue emitGlobalVariableRef(SILLocation loc, VarDecl *var);
+  /// Generate code to obtain the address of the given global variable.
+  ManagedValue emitGlobalVariableRef(SILLocation loc, VarDecl *var,
+                                     Optional<ActorIsolation> actorIso);
 
   /// Generate a lazy global initializer.
   void emitLazyGlobalInitializer(PatternBindingDecl *binding,

lib/SILGen/SILGenGlobalVariable.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "SILGenFunction.h"
+#include "ExecutorBreadcrumb.h"
 #include "ManagedValue.h"
 #include "Scope.h"
 #include "swift/AST/ASTMangler.h"
@@ -66,7 +67,8 @@ SILGlobalVariable *SILGenModule::getSILGlobalVariable(VarDecl *gDecl,
 }
 
 ManagedValue
-SILGenFunction::emitGlobalVariableRef(SILLocation loc, VarDecl *var) {
+SILGenFunction::emitGlobalVariableRef(SILLocation loc, VarDecl *var,
+                                      Optional<ActorIsolation> actorIso) {
   assert(!VarLocs.count(var));
 
   if (var->isLazilyInitializedGlobal()) {
@@ -75,7 +77,21 @@ SILGenFunction::emitGlobalVariableRef(SILLocation loc, VarDecl *var) {
                             SILDeclRef(var, SILDeclRef::Kind::GlobalAccessor),
                                                   NotForDefinition);
     SILValue accessor = B.createFunctionRefFor(loc, accessorFn);
+
+    // The accessor to obtain a global's address may need to initialize the
+    // variable first. So, we must call this accessor with the same
+    // isolation that the variable itself requires during access.
+    ExecutorBreadcrumb prevExecutor = emitHopToTargetActor(loc, actorIso,
+                                                                /*base=*/None);
+
     SILValue addr = B.createApply(loc, accessor, SubstitutionMap(), {});
+
+    // FIXME: often right after this, we will again hop to the actor to
+    // read from this address. it would be better to merge these two hops
+    // pairs of hops together. Alternatively, teaching optimizations to
+    // expand the scope of two nearly-adjacent pairs would be good.
+    prevExecutor.emit(*this, loc); // hop back after call.
+
     // FIXME: It'd be nice if the result of the accessor was natively an
     // address.
     addr = B.createPointerToAddress(

lib/SILGen/SILGenLValue.cpp

@@ -2813,7 +2813,7 @@ void LValue::addNonMemberVarComponent(SILGenFunction &SGF, SILLocation loc,
 
       // The only other case that should get here is a global variable.
       if (!address) {
-        address = SGF.emitGlobalVariableRef(Loc, Storage);
+        address = SGF.emitGlobalVariableRef(Loc, Storage, ActorIso);
       } else {
         assert(!ActorIso && "local var should not be actor isolated!");
       }

test/Concurrency/Runtime/mainactor.swift

@@ -68,6 +68,22 @@ actor A {
   return await enterMainActor(0) + 1
 }
 
+@MainActor func mainActorFn() -> Int {
+  checkIfMainQueue(expectedAnswer: true)
+  return 10
+}
+
+@MainActor
+struct S {
+  static var bacteria: Int = mainActorFn()
+}
+
+@MainActor
+class C {
+  static var bacteria: Int = mainActorFn()
+  lazy var amoeba: Int = mainActorFn()
+  nonisolated init() {}
+}
 
 // CHECK: starting
 // CHECK-NOT: ERROR
@@ -115,5 +131,15 @@ actor A {
       }
     }
     _ = await task.value
+
+    // Check that initializers for stored properties are on the right actor
+    let t1 = Task.detached { () -> Int in
+      let c = C()
+      return await c.amoeba
+    }
+    let t2 = Task.detached { () -> Int in
+      return await S.bacteria + C.bacteria
+    }
+    _ = await t1.value + t2.value
   }
 }

test/Concurrency/property_initializers.swift

@@ -0,0 +1,18 @@
+// RUN: %target-typecheck-verify-swift -disable-availability-checking -warn-concurrency
+// REQUIRES: concurrency
+
+
+@MainActor
+func mainActorFn() -> Int { return 0 } // expected-note 2 {{calls to global function 'mainActorFn()' from outside of its actor context are implicitly asynchronous}}
+
+@MainActor
+class C {
+  var x: Int = mainActorFn() // expected-error {{call to main actor-isolated global function 'mainActorFn()' in a synchronous nonisolated context}}
+
+  lazy var y: Int = mainActorFn()
+
+  static var z: Int = mainActorFn()
+}
+
+@MainActor
+var x: Int = mainActorFn() // expected-error {{call to main actor-isolated global function 'mainActorFn()' in a synchronous nonisolated context}}

test/SILGen/hop_to_executor_async_prop.swift

@@ -488,6 +488,10 @@ struct Container {
     }
 
     // CHECK-LABEL: sil hidden [ossa] @$s4test9ContainerV12accessTuple3SfyYaF : $@convention(method) @async (@guaranteed Container) -> Float {
+    // CHECK:     [[ADDRESS_ACCESSOR:%[0-9]+]] = function_ref @$s4test9ContainerV12staticCircleSi_SitSg_Sftvau : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
+    // CHECK:     = apply [[ADDRESS_ACCESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $Optional<Builtin.Executor>
     // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
     // CHECK:     [[ACCESS:%[0-9]+]] = begin_access [read] [dynamic] {{%[0-9]+}} : $*(Optional<(Int, Int)>, Float)
     // CHECK:     [[ADDR:%[0-9]+]] = tuple_element_addr [[ACCESS]] : $*(Optional<(Int, Int)>, Float), 1
@@ -500,6 +504,10 @@ struct Container {
     }
 
     // CHECK-LABEL: sil hidden [ossa] @$s4test9ContainerV12accessTuple4SiSgyYaFZ : $@convention(method) @async (@thin Container.Type) -> Optional<Int> {
+    // CHECK:     [[ADDRESS_ACCESSOR:%[0-9]+]] = function_ref @$s4test9ContainerV12staticCircleSi_SitSg_Sftvau : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
+    // CHECK:     = apply [[ADDRESS_ACCESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $Optional<Builtin.Executor>
     // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
     // CHECK:     [[ACCESS:%[0-9]+]] = begin_access [read] [dynamic] {{%[0-9]+}} : $*(Optional<(Int, Int)>, Float)
     // CHECK:     [[ADDR:%[0-9]+]] = tuple_element_addr [[ACCESS]] : $*(Optional<(Int, Int)>, Float), 0
@@ -522,6 +530,10 @@ struct Container {
 
 
     // CHECK-LABEL: sil hidden [ossa] @$s4test9ContainerV8getCountSiyYaFZ : $@convention(method) @async (@thin Container.Type) -> Int {
+    // CHECK:     [[ADDRESS_ACCESSOR:%[0-9]+]] = function_ref @$s4test9ContainerV7counterSivau : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
+    // CHECK:     = apply [[ADDRESS_ACCESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $Optional<Builtin.Executor>
     // CHECK:   hop_to_executor {{%[0-9]+}} : $MainActor
     // CHECK:   {{%[0-9]+}} = begin_access [read] [dynamic] {{%[0-9]+}} : $*Int
     // CHECK:   {{%[0-9]+}} = load [trivial] {{%[0-9]+}} : $*Int
@@ -534,6 +546,10 @@ struct Container {
 
     // CHECK-LABEL: sil hidden [ossa] @$s4test9ContainerV8getValueSiSgyYaFZ : $@convention(method) @async (@thin Container.Type) -> Optional<Int> {
     // CHECK: bb0(%0 : $@thin Container.Type):
+    // CHECK:     [[ADDRESS_ACCESSOR:%[0-9]+]] = function_ref @$s4test9ContainerV4thisACSgvau : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
+    // CHECK:     = apply [[ADDRESS_ACCESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $Optional<Builtin.Executor>
     // CHECK:    [[MAIN:%[0-9]+]] = begin_borrow {{%[0-9]+}} : $MainActor
     // CHECK:    [[PREV:%[0-9]+]] = builtin "getCurrentExecutor"() : $Optional<Builtin.Executor>
     // CHECK:    hop_to_executor [[MAIN]] : $MainActor
@@ -556,19 +572,23 @@ struct Container {
 
     // CHECK-LABEL: sil hidden [ossa] @$s4test9ContainerV10getOrCrashSfyYaFZ : $@convention(method) @async (@thin Container.Type) -> Float {
     // CHECK: bb0({{%[0-9]+}} : $@thin Container.Type):
+    // CHECK:     [[ADDRESS_ACCESSOR:%[0-9]+]] = function_ref @$s4test9ContainerV4thisACSgvau : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
+    // CHECK:     = apply [[ADDRESS_ACCESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $Optional<Builtin.Executor>
     // CHECK:    [[MAIN:%[0-9]+]] = begin_borrow {{%[0-9]+}} : $MainActor
     // CHECK:    [[PREV:%[0-9]+]] = builtin "getCurrentExecutor"() : $Optional<Builtin.Executor>
     // CHECK:    hop_to_executor [[MAIN]] : $MainActor
     // CHECK:    [[ACCESS:%[0-9]+]] = begin_access [read] [dynamic] {{%[0-9]+}} : $*Optional<Container>
-    // CHECK:    switch_enum_addr %11 : $*Optional<Container>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[CRASH_BB:bb[0-9]+]]
+    // CHECK:    switch_enum_addr [[ACCESS]] : $*Optional<Container>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[CRASH_BB:bb[0-9]+]]
     //
     // CHECK: [[CRASH_BB]]:
     // CHECK-NOT:   hop_to_executor {{%[0-9]+}}
     // CHECK:       unreachable
     //
     // CHECK: [[SOME_BB]]:
-    // CHECK:       [[DATA_ADDR:%[0-9]+]] = unchecked_take_enum_data_addr %11 : $*Optional<Container>, #Optional.some!enumelt
-    // CHECK:       [[ELEM_ADDR:%[0-9]+]] = struct_element_addr %22 : $*Container, #Container.iso
+    // CHECK:       [[DATA_ADDR:%[0-9]+]] = unchecked_take_enum_data_addr [[ACCESS]] : $*Optional<Container>, #Optional.some!enumelt
+    // CHECK:       [[ELEM_ADDR:%[0-9]+]] = struct_element_addr [[DATA_ADDR]] : $*Container, #Container.iso
     // CHECK:       [[PREV_AGAIN:%[0-9]+]] = builtin "getCurrentExecutor"() : $Optional<Builtin.Executor>
     // CHECK:       hop_to_executor {{%[0-9]+}} : $Cat
     // CHECK:       {{%[0-9]+}} = load [trivial] [[ELEM_ADDR]] : $*Float
@@ -581,19 +601,22 @@ struct Container {
 
     // CHECK-LABEL: sil hidden [ossa] @$s4test9ContainerV13getRefOrCrashAA6CatBoxCyYaFZ : $@convention(method) @async (@thin Container.Type) -> @owned CatBox {
     // CHECK: bb0({{%[0-9]+}} : $@thin Container.Type):
+    // CHECK:     [[ADDRESS_ACCESSOR:%[0-9]+]] = function_ref @$s4test9ContainerV4thisACSgvau : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $MainActor
+    // CHECK:     = apply [[ADDRESS_ACCESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+    // CHECK:     hop_to_executor {{%[0-9]+}} : $Optional<Builtin.Executor>
     // CHECK:    [[MAIN:%[0-9]+]] = begin_borrow {{%[0-9]+}} : $MainActor
     // CHECK:    [[PREV:%[0-9]+]] = builtin "getCurrentExecutor"() : $Optional<Builtin.Executor>
     // CHECK:    hop_to_executor [[MAIN]] : $MainActor
     // CHECK:    [[ACCESS:%[0-9]+]] = begin_access [read] [dynamic] {{%[0-9]+}} : $*Optional<Container>
-    // CHECK:    switch_enum_addr %11 : $*Optional<Container>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[CRASH_BB:bb[0-9]+]]
+    // CHECK:    switch_enum_addr [[ACCESS]] : $*Optional<Container>, case #Optional.some!enumelt: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[CRASH_BB:bb[0-9]+]]
     //
     // CHECK: [[CRASH_BB]]:
-    // CHECK-NOT:   hop_to_executor {{%[0-9]+}}
     // CHECK:       unreachable
     //
     // CHECK: [[SOME_BB]]:
-    // CHECK:       [[DATA_ADDR:%[0-9]+]] = unchecked_take_enum_data_addr %11 : $*Optional<Container>, #Optional.some!enumelt
-    // CHECK:       [[ELEM_ADDR:%[0-9]+]] = struct_element_addr %22 : $*Container, #Container.iso
+    // CHECK:       [[DATA_ADDR:%[0-9]+]] = unchecked_take_enum_data_addr [[ACCESS]] : $*Optional<Container>, #Optional.some!enumelt
+    // CHECK:       [[ELEM_ADDR:%[0-9]+]] = struct_element_addr [[DATA_ADDR]] : $*Container, #Container.iso
     // CHECK:       [[PREV_AGAIN:%[0-9]+]] = builtin "getCurrentExecutor"() : $Optional<Builtin.Executor>
     // CHECK:       hop_to_executor {{%[0-9]+}} : $Cat
     // CHECK:       {{%[0-9]+}} = load [copy] [[ELEM_ADDR]] : $*CatBox
@@ -644,3 +667,27 @@ struct Blah {
         }
     }
 }
+
+@MainActor
+func getTemperature() -> Int { return 0 }
+
+@MainActor
+class Polar {
+  static var temperature: Int = getTemperature()
+}
+
+
+// CHECK-LABEL: sil hidden{{.*}} @$s4test20accessStaticIsolatedSiyYaF : $@convention(thin) @async () -> Int {
+// CHECK:        [[ADDRESSOR:%[0-9]+]] = function_ref @$s4test5PolarC11temperatureSivau : $@convention(thin) () -> Builtin.RawPointer
+// CHECK:        hop_to_executor {{%.*}} : $MainActor
+// CHECK-NEXT:   [[RAW_ADDR:%[0-9]+]] = apply [[ADDRESSOR]]() : $@convention(thin) () -> Builtin.RawPointer
+// CHECK-NEXT:   hop_to_executor {{%.*}} : $Optional<Builtin.Executor>
+// CHECK:        [[ADDR:%[0-9]+]] = pointer_to_address [[RAW_ADDR]] : $Builtin.RawPointer to [strict] $*Int
+// CHECK:        hop_to_executor {{%.*}} : $MainActor
+// CHECK:        {{%.*}} = load [trivial] {{%.*}} : $*Int
+// CHECK:        hop_to_executor {{%.*}} : $Optional<Builtin.Executor>
+func accessStaticIsolated() async -> Int {
+  return await Polar.temperature
+}
+
+