Merge pull request #10245 from slavapestov/local-generic-function-captures

SILGen: Fix problems with local generic functions

Author: slavapestov

lib/SILGen/SILGenApply.cpp

@@ -868,13 +868,17 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
 
     auto afd = dyn_cast<AbstractFunctionDecl>(e->getDecl());
 
+    CaptureInfo captureInfo;
+
     // Otherwise, we have a statically-dispatched call.
-    SubstitutionList subs;
-    if (e->getDeclRef().isSpecialized() &&
-        (!afd ||
-         !afd->getDeclContext()->isLocalContext() ||
-         afd->getCaptureInfo().hasGenericParamCaptures()))
-      subs = e->getDeclRef().getSubstitutions();
+    SubstitutionList subs = e->getDeclRef().getSubstitutions();
+
+    if (afd) {
+      captureInfo = SGF.SGM.Types.getLoweredLocalCaptures(afd);
+      if (afd->getDeclContext()->isLocalContext() &&
+          !captureInfo.hasGenericParamCaptures())
+        subs = SubstitutionList();
+    }
 
     // Enum case constructor references are open-coded.
     if (isa<EnumElementDecl>(e->getDecl()))
@@ -884,7 +888,7 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
 
     // If the decl ref requires captures, emit the capture params.
     if (afd) {
-      if (SGF.SGM.M.Types.hasLoweredLocalCaptures(afd)) {
+      if (!captureInfo.getCaptures().empty()) {
         SmallVector<ManagedValue, 4> captures;
         SGF.emitCaptures(e, afd, CaptureEmission::ImmediateApplication,
                          captures);
@@ -4900,6 +4904,15 @@ static Callee getBaseAccessorFunctionRef(SILGenFunction &SGF,
                                          SubstitutionList subs) {
   auto *decl = cast<AbstractFunctionDecl>(constant.getDecl());
 
+  // The accessor might be a local function that does not capture any
+  // generic parameters, in which case we don't want to pass in any
+  // substitutions.
+  auto captureInfo = SGF.SGM.Types.getLoweredLocalCaptures(decl);
+  if (decl->getDeclContext()->isLocalContext() &&
+      !captureInfo.hasGenericParamCaptures()) {
+    subs = SubstitutionList();
+  }
+
   // If this is a method in a protocol, generate it as a protocol call.
   if (isa<ProtocolDecl>(decl->getDeclContext())) {
     assert(!isDirectUse && "direct use of protocol accessor?");

lib/Sema/TypeCheckCaptures.cpp

@@ -229,10 +229,14 @@ class FindCapturedVars : public ASTWalker {
   std::pair<bool, Expr *> walkToDeclRefExpr(DeclRefExpr *DRE) {
     auto *D = DRE->getDecl();
 
-    // Capture the generic parameters of the decl.
-    if (!AFR.isObjC() || !D->isObjC() || isa<ConstructorDecl>(D)) {
-      for (auto sub : DRE->getDeclRef().getSubstitutions()) {
-        checkType(sub.getReplacement(), DRE->getLoc());
+    // Capture the generic parameters of the decl, unless it's a
+    // local declaration in which case we will pick up generic
+    // parameter references transitively.
+    if (!D->getDeclContext()->isLocalContext()) {
+      if (!AFR.isObjC() || !D->isObjC() || isa<ConstructorDecl>(D)) {
+        for (auto sub : DRE->getDeclRef().getSubstitutions()) {
+          checkType(sub.getReplacement(), DRE->getLoc());
+        }
       }
     }
 

test/SILGen/generic_closures.swift

@@ -8,14 +8,27 @@ var zero: Int
 func generic_nondependent_context<T>(_ x: T, y: Int) -> Int {
   func foo() -> Int { return y }
 
+  func bar() -> Int { return y }
+
   // CHECK: [[FOO:%.*]] = function_ref @_T016generic_closures0A21_nondependent_context{{.*}} : $@convention(thin) (Int) -> Int
   // CHECK: [[FOO_CLOSURE:%.*]] = partial_apply [[FOO]](%1)
   // CHECK: destroy_value [[FOO_CLOSURE]]
   let _ = foo
 
+  // CHECK: [[BAR:%.*]] = function_ref @_T016generic_closures0A21_nondependent_context{{.*}} : $@convention(thin) (Int) -> Int
+  // CHECK: [[BAR_CLOSURE:%.*]] = partial_apply [[BAR]](%1)
+  // CHECK: destroy_value [[BAR_CLOSURE]]
+  let _ = bar
+
   // CHECK: [[FOO:%.*]] = function_ref @_T016generic_closures0A21_nondependent_context{{.*}} : $@convention(thin) (Int) -> Int
   // CHECK: [[FOO_CLOSURE:%.*]] = apply [[FOO]]
-  return foo()
+  _ = foo()
+
+  // CHECK: [[BAR:%.*]] = function_ref @_T016generic_closures0A21_nondependent_context{{.*}} : $@convention(thin) (Int) -> Int
+  // CHECK: [[BAR_CLOSURE:%.*]] = apply [[BAR]]
+
+  // CHECK: [[BAR_CLOSURE]]
+  return bar()
 }
 
 // CHECK-LABEL: sil hidden @_T016generic_closures0A8_capture{{[_0-9a-zA-Z]*}}F
@@ -29,6 +42,8 @@ func generic_capture<T>(_ x: T) -> Any.Type {
 
   // CHECK: [[FOO:%.*]] = function_ref @_T016generic_closures0A8_capture{{.*}} : $@convention(thin) <τ_0_0> () -> @thick Any.Type
   // CHECK: [[FOO_CLOSURE:%.*]] = apply [[FOO]]<T>()
+
+  // CHECK: return [[FOO_CLOSURE]]
   return foo()
 }
 
@@ -43,6 +58,8 @@ func generic_capture_cast<T>(_ x: T, y: Any) -> Bool {
 
   // CHECK: [[FOO:%.*]] = function_ref @_T016generic_closures0A13_capture_cast{{.*}} : $@convention(thin) <τ_0_0> (@in Any) -> Bool
   // CHECK: [[FOO_CLOSURE:%.*]] = apply [[FOO]]<T>([[ARG:%.*]])
+
+  // CHECK: return [[FOO_CLOSURE]]
   return foo(y)
 }
 
@@ -61,6 +78,8 @@ func generic_nocapture_existential<T>(_ x: T, y: Concept) -> Bool {
 
   // CHECK: [[FOO:%.*]] = function_ref @_T016generic_closures0A22_nocapture_existential{{.*}} : $@convention(thin) (@in Concept) -> Bool
   // CHECK: [[FOO_CLOSURE:%.*]] = apply [[FOO]]([[ARG:%.*]])
+
+  // CHECK: return [[FOO_CLOSURE]]
   return foo(y)
 }
 
@@ -75,6 +94,8 @@ func generic_dependent_context<T>(_ x: T, y: Int) -> T {
 
   // CHECK: [[FOO:%.*]] = function_ref @_T016generic_closures0A18_dependent_context{{.*}} : $@convention(thin) <τ_0_0> (@owned <τ_0_0> { var τ_0_0 } <τ_0_0>) -> @out τ_0_0
   // CHECK: [[FOO_CLOSURE:%.*]] = apply [[FOO]]<T>
+
+  // CHECK: return
   return foo()
 }
 

test/SILGen/properties.swift

@@ -325,6 +325,25 @@ func logical_local_get(_ x: Int) -> Int {
 // CHECK-: sil private [[PROP_GET_CLOSURE]]
 // CHECK: bb0(%{{[0-9]+}} : $Int):
 
+func logical_generic_local_get<T>(_ x: Int, _: T) {
+  var prop1: Int {
+    get {
+      return x
+    }
+  }
+
+  _ = prop1
+
+  var prop2: Int {
+    get {
+      _ = T.self
+      return x
+    }
+  }
+
+  _ = prop2
+}
+
 // CHECK-LABEL: sil hidden @_T010properties26logical_local_captured_get{{[_0-9a-zA-Z]*}}F
 func logical_local_captured_get(_ x: Int) -> Int {
   var prop : Int {
@@ -654,7 +673,26 @@ func local_observing_property(_ arg: Int) {
 // CHECK: [[PB:%.*]] = project_box [[BOX]]
 // CHECK: store [[ARG]] to [trivial] [[PB]]
 
+func local_generic_observing_property<T>(_ arg: Int, _: T) {
+  var localproperty1: Int = arg {
+    didSet {
+      takeInt(localproperty1)
+    }
+  }
+  
+  takeInt(localproperty1)
+  localproperty1 = arg
 
+  var localproperty2: Int = arg {
+    didSet {
+      _ = T.self
+      takeInt(localproperty2)
+    }
+  }
+  
+  takeInt(localproperty2)
+  localproperty2 = arg
+}
 
 
 // <rdar://problem/16006333> observing properties don't work in @objc classes