[4.1] Sema: Request the layout for generic parameters if there is a body

Cherry-picked: "Merge pull request #14411 from
aschwaighofer/sema_require_layout_generic_params"

Generic parameters can become sources of metadata types and
conformances. To access them the layout needs to be available to IRGen.

rdar://37086144
SR-6879

* Explanation: With swift-4.1-branch we made requiring the layout of nominal
types more lazy. Too lazy, in the case of parameters that are nominal and
dependent because such parameters can be used to recover the bound generic
type variables (and their conformances) by IRGen which requires their
layout.

* Scope: Introduced with swift-4.1-branch (see above). Causes runtime
crash because type metadata / conformances are loaded from wrong
offsets.

* Testing: Swift CI tests added. The project from the bug report
executes successfully after patch.

* Risk: Low. We add a requirement to typecheck the nominal layout (which
we did pre swift-4.1 lazyness.

* Reviewed: Doug G

Author: aschwaighofer

lib/Sema/CSApply.cpp

@@ -7441,6 +7441,10 @@ namespace {
         if (tc.coerceParameterListToType(params, closure, fnType))
           return { false, nullptr };
 
+        // Require layout of dependent types that could be used to materialize
+        // metadata types/conformances during IRGen.
+        tc.requestRequiredNominalTypeLayoutForParameters(params);
+
         // If this is a single-expression closure, convert the expression
         // in the body to the result type of the closure.
         if (closure->hasSingleExpressionBody()) {

lib/Sema/TypeCheckPattern.cpp

@@ -755,6 +755,25 @@ static bool validateParameterType(ParamDecl *decl, DeclContext *DC,
   return hadError;
 }
 
+/// Request nominal layout for any types that could be sources of typemetadata
+/// or conformances.
+void TypeChecker::requestRequiredNominalTypeLayoutForParameters(
+    ParameterList *PL) {
+  for (auto param : *PL) {
+    if (!param->hasType())
+      continue;
+
+    // Generic types are sources for typemetadata and conformances. If a
+    // parameter is of dependent type then the body of a function with said
+    // parameter could potentially require the generic type's layout to
+    // recover them.
+    if (auto *nominalDecl = dyn_cast_or_null<NominalTypeDecl>(
+            param->getType()->getAnyGeneric())) {
+      requestNominalLayout(nominalDecl);
+    }
+  }
+}
+
 /// Type check a parameter list.
 bool TypeChecker::typeCheckParameterList(ParameterList *PL, DeclContext *DC,
                                          TypeResolutionOptions options,

lib/Sema/TypeCheckStmt.cpp

@@ -1361,6 +1361,9 @@ bool TypeChecker::typeCheckAbstractFunctionBody(AbstractFunctionDecl *AFD) {
   if (DebugTimeFunctionBodies || WarnLongFunctionBodies)
     timer.emplace(AFD, DebugTimeFunctionBodies, WarnLongFunctionBodies);
 
+  for (auto paramList : AFD->getParameterLists())
+    requestRequiredNominalTypeLayoutForParameters(paramList);
+
   if (typeCheckAbstractFunctionBodyUntil(AFD, SourceLoc()))
     return true;
 

lib/Sema/TypeChecker.h

@@ -1824,11 +1824,15 @@ class TypeChecker final : public LazyResolver {
 
   bool typeCheckCatchPattern(CatchStmt *S, DeclContext *dc);
 
+  /// Request nominal layout for any types that could be sources of typemetadata
+  /// or conformances.
+  void requestRequiredNominalTypeLayoutForParameters(ParameterList *PL);
+
   /// Type check a parameter list.
   bool typeCheckParameterList(ParameterList *PL, DeclContext *dc,
                               TypeResolutionOptions options,
                               GenericTypeResolver &resolver);
-  
+
   /// Coerce a pattern to the given type.
   ///
   /// \param P The pattern, which may be modified by this coercion.

test/multifile/Inputs/require-layout-generic-class.swift

@@ -0,0 +1,13 @@
+public class Base<T> {
+  var t: T
+  init(_ a: T) {
+    t = a
+  }
+}
+
+public class Sub<T> : Base<T> {
+}
+
+public func requestTypeThrough<T>(closure: (Sub<T>) -> (), arg: T) {
+  closure(Sub(arg))
+}

test/multifile/require-layout-generic-arg-closure.swift

@@ -0,0 +1,29 @@
+// RUN: %target-swift-frontend -module-name test -emit-ir -verify -primary-file %s %S/Inputs/require-layout-generic-class.swift | %FileCheck --check-prefix=FILE1 %s
+// RUN: %target-swift-frontend -module-name test -emit-ir -verify %s -primary-file %S/Inputs/require-layout-generic-class.swift | %FileCheck --check-prefix=FILE2 %s
+
+// REQUIRES: CPU=x86_64
+
+// The offset of the typemetadata in the class typemetadata must match.
+
+// FILE1-LABEL: define internal swiftcc void @{{.*}}S4test12requestType{{.*}}(%T4test3SubC*)
+// FILE1: entry:
+// FILE1:   [[T1:%.*]] = bitcast %T4test3SubC* %0 to %swift.type**
+// FILE1:   [[TYPEMETADATA:%.*]] = load %swift.type*, %swift.type** [[T1]]
+// FILE1:   [[T2:%.*]] = bitcast %swift.type* [[TYPEMETADATA]] to %swift.type**
+// This offset of T needs to be the same as the offset below.
+// FILE1:   [[T_PTR:%.*]] = getelementptr inbounds %swift.type*, %swift.type** [[T2]], i64 16
+// FILE1:   [[T:%.*]] = load %swift.type*, %swift.type** [[T_PTR]]
+// FILE1:   call %swift.type* @{{.*}}S4test3SubCMa{{.*}}(%swift.type* [[T]])
+
+public func requestType2<T>(x: T) {
+  requestTypeThrough(closure: { x in print(x) }, arg: x)
+}
+// FILE2-LABEL: define private %swift.type* @create_generic_metadata_Sub(%swift.type_pattern*, i8**)
+// FILE2:   [[T_ADDR:%.*]] = bitcast i8** %1 to %swift.type**
+// FILE2:   [[T:%.*]] = load %swift.type*, %swift.type** %2
+// FILE2:   [[CLASSMETADATA:%.*]] = call %swift.type* @swift_allocateGenericClassMetadata
+// FILE2:   [[ADDR:%.*]] = bitcast %swift.type* [[CLASSMETADATA]] to i8**
+// This offset of T here needs to be the same as the offset above.
+// FILE2:   [[T_IN_CLASSMETADATA:%.*]] = getelementptr inbounds i8*, i8** [[ADDR]], i64 16
+// FILE2:   [[T2:%.*]] = bitcast %swift.type* [[T]] to i8*
+// FILE2:   store i8* [[T2]], i8** [[T_IN_CLASSMETADATA]]

test/multifile/require-layout-generic-arg-subscript.swift

@@ -0,0 +1,33 @@
+// RUN: %target-swift-frontend -module-name test -emit-ir -verify -primary-file %s %S/Inputs/require-layout-generic-class.swift | %FileCheck --check-prefix=FILE1 %s
+// RUN: %target-swift-frontend -module-name test -emit-ir -verify %s -primary-file %S/Inputs/require-layout-generic-class.swift | %FileCheck --check-prefix=FILE2 %s
+
+// REQUIRES: CPU=x86_64
+
+// The offset of the typemetadata in the class typemetadata must match.
+
+// FILE1: define hidden swiftcc i64 @{{.*}}S4test12AccessorTestCySiAA3Sub{{.*}}(%T4test3SubC*, %T4test12AccessorTestC* swiftself)
+// FILE1:   [[T1:%.*]] = bitcast %T4test3SubC* %0 to %swift.type**
+// FILE1:   [[TYPEMETADATA:%.*]] = load %swift.type*, %swift.type** [[T1]]
+// FILE1:   [[T2:%.*]] = bitcast %swift.type* [[TYPEMETADATA]] to %swift.type**
+// This offset must match the offset below.
+// FILE1:   [[T_IN_CLASSMETADATA:%.*]] = getelementptr inbounds %swift.type*, %swift.type** [[T2]], i64 16
+// FILE1:   [[T:%.*]] = load %swift.type*, %swift.type** [[T_IN_CLASSMETADATA]]
+// FILE1:   call %swift.type* @swift_getMetatypeMetadata(%swift.type* [[T]])
+public class AccessorTest {
+  subscript<T>(_ a: Sub<T>) -> Int {
+    get {
+      print(T.self)
+      return 1
+    }
+  }
+}
+
+// FILE2-LABEL: define private %swift.type* @create_generic_metadata_Sub(%swift.type_pattern*, i8**)
+// FILE2:   [[T_ADDR:%.*]] = bitcast i8** %1 to %swift.type**
+// FILE2:   [[T:%.*]] = load %swift.type*, %swift.type** %2
+// FILE2:   [[CLASSMETADATA:%.*]] = call %swift.type* @swift_allocateGenericClassMetadata
+// FILE2:   [[ADDR:%.*]] = bitcast %swift.type* [[CLASSMETADATA]] to i8**
+// This offset must match the offset above.
+// FILE2:   [[T_IN_CLASSMETADATA:%.*]] = getelementptr inbounds i8*, i8** [[ADDR]], i64 16
+// FILE2:   [[T2:%.*]] = bitcast %swift.type* [[T]] to i8*
+// FILE2:   store i8* [[T2]], i8** [[T_IN_CLASSMETADATA]]

test/multifile/require-layout-generic-arg.swift

@@ -0,0 +1,27 @@
+// RUN: %target-swift-frontend -module-name test -emit-ir -verify -primary-file %s %S/Inputs/require-layout-generic-class.swift | %FileCheck --check-prefix=FILE1 %s
+// RUN: %target-swift-frontend -module-name test -emit-ir -verify %s -primary-file %S/Inputs/require-layout-generic-class.swift | %FileCheck --check-prefix=FILE2 %s
+
+// REQUIRES: CPU=x86_64
+
+// The offset of the typemetadata in the class typemetadata must match.
+
+// FILE1-LABEL: define{{.*}} swiftcc void @{{.*}}S4test11requestTypeyyAA3Sub{{.*}}(%T4test3SubC*)
+// FILE1:  [[T1:%.*]] = bitcast %T4test3SubC* %0 to %swift.type**
+// FILE1:  [[TYPEMETADATA:%.*]] = load %swift.type*, %swift.type** [[T1]]
+// FILE1:  [[T2:%.*]] = bitcast %swift.type* [[TYPEMETADATA]] to %swift.type**
+// This offset must match the offset below.
+// FILE1:  [[T_PTR:%.*]] = getelementptr inbounds %swift.type*, %swift.type** [[T2]], i64 16
+// FILE1:  [[T:%.*]] = load %swift.type*, %swift.type** [[T_PTR]]
+public func requestType<T>(_ c: Sub<T>) {
+  print(T.self)
+}
+
+// FILE2-LABEL: define private %swift.type* @create_generic_metadata_Sub(%swift.type_pattern*, i8**)
+// FILE2:   [[T_ADDR:%.*]] = bitcast i8** %1 to %swift.type**
+// FILE2:   [[T:%.*]] = load %swift.type*, %swift.type** %2
+// FILE2:   [[CLASSMETADATA:%.*]] = call %swift.type* @swift_allocateGenericClassMetadata
+// FILE2:   [[ADDR:%.*]] = bitcast %swift.type* [[CLASSMETADATA]] to i8**
+// This offset must match the offset above.
+// FILE2:   [[T_IN_CLASSMETADATA:%.*]] = getelementptr inbounds i8*, i8** [[ADDR]], i64 16
+// FILE2:   [[T2:%.*]] = bitcast %swift.type* [[T]] to i8*
+// FILE2:   store i8* [[T2]], i8** [[T_IN_CLASSMETADATA]]

test/multifile/require-layout/main.swift

@@ -0,0 +1,12 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %S/../require-layout-generic-arg.swift %S/../Inputs/require-layout-generic-class.swift %s -o %t/test
+// RUN: %target-run %t/test | %FileCheck %s
+
+// REQUIRES: executable_test
+
+func test() {
+  requestType(Sub(1))
+}
+
+// CHECK: Int
+test()

test/multifile/require-layout2/main.swift

@@ -0,0 +1,12 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %S/../require-layout-generic-arg-closure.swift %S/../Inputs/require-layout-generic-class.swift %s -o %t/test
+// RUN: %target-run %t/test | %FileCheck %s
+
+// REQUIRES: executable_test
+
+func test() {
+  requestType2(x: 1)
+}
+
+// CHECK: test.Sub<Swift.Int>
+test()

test/multifile/require-layout3/main.swift

@@ -0,0 +1,12 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-build-swift %S/../require-layout-generic-arg-subscript.swift %S/../Inputs/require-layout-generic-class.swift %s -o %t/test
+// RUN: %target-run %t/test | %FileCheck %s
+
+// REQUIRES: executable_test
+
+func test() {
+  _ = AccessorTest()[Sub(1)]
+}
+
+// CHECK: Int
+test()