[WASM] Create WasmTypeLayout in a way that is compatible with modular…

… compilation.

PiperOrigin-RevId: 562760101

build_defs/internal_do_not_use/j2wasm_common.bzl

@@ -23,7 +23,15 @@ def _compile(
         exported_plugins = exported_plugins,
         backend = "WASM_MODULAR",
         output_jar = output_jar,
-        javac_opts = javac_opts,
+        javac_opts = javac_opts + [
+            # Preserve the private fields in turbine compilation. In order to create wasm structs for
+            # Java classes, all the fields from the super classes need to be seen even if compiling
+            # in a different library.
+            "-XDturbine.emitPrivateFields",
+            # Disable analysis for thread safety since it does not expect to see
+            # private fields from dependencies.
+            "-Xep:ThreadSafe:OFF",
+        ],
         artifact_suffix = artifact_suffix,
     )
 

transpiler/java/com/google/j2cl/transpiler/ast/DeclaredTypeDescriptor.java

@@ -451,6 +451,23 @@ public MethodDescriptor getCopyMethodDescriptor() {
         .build();
   }
 
+  /** Returns the FieldDescriptor corresponding to the enclosing class instance. */
+  public FieldDescriptor getFieldDescriptorForEnclosingInstance() {
+    return FieldDescriptor.newBuilder()
+        .setEnclosingTypeDescriptor(toUnparameterizedTypeDescriptor())
+        .setName("this")
+        .setTypeDescriptor(
+            getEnclosingTypeDescriptor()
+                // Consider the outer instance type to be nullable to be make the type consistent
+                // across all places where it is used (backing field and constructor parameters).
+                .toNullable())
+        .setSynthetic(true)
+        .setFinal(true)
+        .setSynthetic(true)
+        .setOrigin(FieldOrigin.SYNTHETIC_OUTER_FIELD)
+        .build();
+  }
+
   @Memoized
   @Override
   public String getUniqueId() {

transpiler/java/com/google/j2cl/transpiler/backend/wasm/WasmGenerationEnvironment.java

@@ -17,6 +17,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 import static java.lang.String.format;
 import static java.util.Comparator.comparingInt;
 
@@ -364,21 +365,39 @@ public JsMethodImport getJsMethodImport(MethodDescriptor methodDescriptor) {
         .sorted(comparingInt(t -> t.getDeclaration().getClassHierarchyDepth()))
         .forEach(
             t -> {
-              WasmTypeLayout superTypeLayout = null;
-              if (t.getSuperTypeDescriptor() != null) {
-                superTypeLayout =
-                    wasmTypeLayoutByTypeDeclaration.get(
-                        t.getSuperTypeDescriptor().getTypeDeclaration());
-              }
-              wasmTypeLayoutByTypeDeclaration.put(
-                  t.getDeclaration(), WasmTypeLayout.create(t, superTypeLayout));
+              TypeDeclaration typeDeclaration = t.getDeclaration();
+              WasmTypeLayout superWasmLayout =
+                  getWasmLayout(typeDeclaration.getSuperTypeDeclaration());
+              var previous =
+                  wasmTypeLayoutByTypeDeclaration.put(
+                      typeDeclaration, WasmTypeLayout.createFromType(t, superWasmLayout));
+              // Since the layout is for a type in the AST, it is expected that the
+              // layout was not already created from the descriptor.
+              checkState(previous == null);
             });
 
     assignInterfaceSlots(library);
 
     this.jsImports = jsImports;
   }
 
+  private WasmTypeLayout getWasmLayout(TypeDeclaration typeDeclaration) {
+    if (typeDeclaration == null) {
+      return null;
+    }
+    if (!wasmTypeLayoutByTypeDeclaration.containsKey(typeDeclaration)) {
+      WasmTypeLayout wasmTypeLayout =
+          WasmTypeLayout.createFromTypeDeclaration(
+              typeDeclaration, getWasmTypeLayout(typeDeclaration.getSuperTypeDeclaration()));
+      // If the supertype layout was not created by the type it is requested here,
+      // it means that the type is from a different library and is ok to
+      // create its layout from the type model.
+      wasmTypeLayoutByTypeDeclaration.put(typeDeclaration, wasmTypeLayout);
+      return wasmTypeLayout;
+    }
+    return wasmTypeLayoutByTypeDeclaration.get(typeDeclaration);
+  }
+
   /**
    * Assigns a slot number (i.e. an index in the itable array) for each interface in the itable.
    *

transpiler/java/com/google/j2cl/transpiler/backend/wasm/WasmTypeLayout.java

@@ -26,41 +26,59 @@
 import com.google.j2cl.transpiler.ast.FieldDescriptor;
 import com.google.j2cl.transpiler.ast.MethodDescriptor;
 import com.google.j2cl.transpiler.ast.Type;
+import com.google.j2cl.transpiler.ast.TypeDeclaration;
 import com.google.j2cl.transpiler.ast.TypeDescriptors;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Comparator;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Stream;
 import javax.annotation.Nullable;
 
 /** Runtime representation of a Java class in Wasm. */
 @AutoValue
 abstract class WasmTypeLayout {
-  static WasmTypeLayout create(Type javaType, WasmTypeLayout wasmSupertypeLayout) {
-    return new AutoValue_WasmTypeLayout(javaType, wasmSupertypeLayout);
+  /** Create a layout for a type that is declared the library being compiled. */
+  static WasmTypeLayout createFromType(Type javaType, WasmTypeLayout wasmSupertypeLayout) {
+    return new AutoValue_WasmTypeLayout(
+        javaType, javaType.getTypeDescriptor(), wasmSupertypeLayout);
   }
 
-  /** The Java class represented by this Wasm type. */
+  /** Create a layout for a type that is declared in a different library. */
+  static WasmTypeLayout createFromTypeDeclaration(
+      TypeDeclaration typeDeclaration, WasmTypeLayout wasmSupertypeLayout) {
+    return new AutoValue_WasmTypeLayout(
+        null, typeDeclaration.toUnparameterizedTypeDescriptor(), wasmSupertypeLayout);
+  }
+
+  /**
+   * The Java class represented by this Wasm type if the type is in the current library, {@code
+   * null} if the type is from a different library.
+   */
+  @Nullable
   abstract Type getJavaType();
 
+  abstract DeclaredTypeDescriptor getTypeDescriptor();
+
   /** The wasm representation of the superclass for this Java class. */
   @Nullable
   abstract WasmTypeLayout getWasmSupertypeLayout();
 
   /** Returns all the fields that will be in the layout for struct for the Java class. */
   @Memoized
   Collection<FieldDescriptor> getAllInstanceFields() {
-    List<FieldDescriptor> instanceFields = new ArrayList<>();
 
-    if (getWasmSupertypeLayout() != null) {
-      instanceFields.addAll(getWasmSupertypeLayout().getAllInstanceFields());
+    WasmTypeLayout wasmSupertypeLayout = getWasmSupertypeLayout();
+    List<FieldDescriptor> instanceFields = new ArrayList<>();
+    if (wasmSupertypeLayout != null) {
+      instanceFields.addAll(wasmSupertypeLayout.getAllInstanceFields());
     }
-    ImmutableList<FieldDescriptor> declaredInstanceFields =
-        getJavaType().getInstanceFields().stream()
-            .map(Field::getDescriptor)
-            .collect(toImmutableList());
-    if (TypeDescriptors.isWasmArraySubtype(getJavaType().getTypeDescriptor())) {
+
+    ImmutableList<FieldDescriptor> declaredInstanceFields = getDeclaredInstanceFields();
+
+    if (TypeDescriptors.isWasmArraySubtype(getTypeDescriptor())) {
       // TODO(b/296475021): Remove the hack to treat the field as overriden by subclass' field.
       // Override the type of the elements field in Wasm arrays by replacing the WasmArray elements
       // field with that of their subtype.
@@ -72,9 +90,48 @@ Collection<FieldDescriptor> getAllInstanceFields() {
     }
 
     instanceFields.addAll(declaredInstanceFields);
+
     return instanceFields;
   }
 
+  private ImmutableList<FieldDescriptor> getDeclaredInstanceFields() {
+    Type type = getJavaType();
+    Stream<FieldDescriptor> declaredFieldDescriptors;
+    if (type != null) {
+      // If the type is in the library, just look at the field instances in the AST of the Type.
+      // In this scenario we will see exactly the instance fields even the ones that are synthesized
+      // for captures.
+      declaredFieldDescriptors = type.getInstanceFields().stream().map(Field::getDescriptor);
+    } else {
+      // If the type is not in the library, look at the declared fields for the type in the type
+      // model; in this case we will only see the instance fields that were declared on the type,
+      // but not the synthetic ones.
+      declaredFieldDescriptors =
+          getTypeDescriptor().getDeclaredFieldDescriptors().stream()
+              .filter(FieldDescriptor::isInstanceMember);
+
+      // The only synthetic field we care for types that are not in the current library is the field
+      // to store the enclosing instance which we can add it explicitly here if needed. In Wasm
+      // declaring structures and initializing instances requires knowing the full structure of the
+      // type, which includes all the fields inherited from supertypes including private fields.
+      // Luckily in Java, types that have other captures can not be subclasses outside the library,
+      // and due to the fact that initialization is behind a factory method, the structures of these
+      // types are never leaked outside the compilation unit the type is defined in.
+      if (getTypeDescriptor().getTypeDeclaration().isCapturingEnclosingInstance()) {
+        declaredFieldDescriptors =
+            Stream.concat(
+                declaredFieldDescriptors,
+                Stream.of(getTypeDescriptor().getFieldDescriptorForEnclosingInstance()));
+      }
+    }
+
+    return declaredFieldDescriptors
+        // Declared fields are sorted by mangled name because they might not appear in the same
+        // order in the AST.
+        .sorted(Comparator.comparing(FieldDescriptor::getMangledName))
+        .collect(toImmutableList());
+  }
+
   /** Returns all the methods that will be part of the vtable for the Java class. */
   Collection<MethodDescriptor> getAllPolymorphicMethods() {
     return getAllPolymorphicMethodsByMangledName().values();
@@ -98,13 +155,13 @@ Map<String, MethodDescriptor> getAllPolymorphicMethodsByMangledName() {
       instanceMethodsByMangledName.putAll(
           getWasmSupertypeLayout().getAllPolymorphicMethodsByMangledName());
     }
-    DeclaredTypeDescriptor typeDescriptor = getJavaType().getTypeDescriptor();
+    DeclaredTypeDescriptor typeDescriptor = getTypeDescriptor();
     for (MethodDescriptor methodDescriptor : typeDescriptor.getPolymorphicMethods()) {
       instanceMethodsByMangledName.put(methodDescriptor.getMangledName(), methodDescriptor);
     }
     // Patch entry for $getClassImpl, since it is explicitly overridden in every class but does not
     // appear as overridden at the right target when calling getPolymorphicMethods().
-    if (!getJavaType().isInterface()) {
+    if (!typeDescriptor.isInterface()) {
       MethodDescriptor getClassMethodDescriptor = getGetClassMethodDescriptor(typeDescriptor);
       instanceMethodsByMangledName.put(
           getClassMethodDescriptor.getMangledName(), getClassMethodDescriptor);

transpiler/java/com/google/j2cl/transpiler/passes/ResolveCaptures.java

@@ -182,7 +182,8 @@ public boolean enterType(Type type) {
             if (type.getDeclaration().isCapturingEnclosingInstance()) {
               type.addMember(
                   0,
-                  Field.Builder.from(getFieldDescriptorForEnclosingInstance(type.getDeclaration()))
+                  Field.Builder.from(
+                          type.getTypeDescriptor().getFieldDescriptorForEnclosingInstance())
                       .setSourcePosition(type.getSourcePosition())
                       .build());
             }
@@ -276,7 +277,9 @@ public Method rewriteMethod(Method method) {
                     ? addParameterAndInitializeBackingField(
                         methodBuilder,
                         0,
-                        getFieldDescriptorForEnclosingInstance(typeDeclaration),
+                        getCurrentType()
+                            .getTypeDescriptor()
+                            .getFieldDescriptorForEnclosingInstance(),
                         isDelegatingConstructor,
                         getCurrentType().getSourcePosition())
                     : null;
@@ -397,9 +400,7 @@ public Expression rewriteThisReference(ThisReference thisReference) {
             do {
               outerFieldAccess =
                   FieldAccess.newBuilder()
-                      .setTarget(
-                          getFieldDescriptorForEnclosingInstance(
-                              currentTypeDescriptor.getTypeDeclaration()))
+                      .setTarget(currentTypeDescriptor.getFieldDescriptorForEnclosingInstance())
                       .setQualifier(outerFieldAccess)
                       .build();
               currentTypeDescriptor = currentTypeDescriptor.getEnclosingTypeDescriptor();
@@ -429,26 +430,6 @@ private static FieldDescriptor getFieldDescriptorForCapture(
         .build();
   }
 
-  /** Returns the FieldDescriptor corresponding to the enclosing class instance. */
-  private FieldDescriptor getFieldDescriptorForEnclosingInstance(
-      TypeDeclaration innerTypeDescriptor) {
-    return FieldDescriptor.newBuilder()
-        .setEnclosingTypeDescriptor(innerTypeDescriptor.toUnparameterizedTypeDescriptor())
-        .setName("this")
-        .setTypeDescriptor(
-            innerTypeDescriptor
-                .getEnclosingTypeDeclaration()
-                .toUnparameterizedTypeDescriptor()
-                // Consider the outer instance type to be nullable to be make the type consistent
-                // across all places where it is used (backing field and constructor parameters).
-                .toNullable())
-        .setSynthetic(true)
-        .setFinal(true)
-        .setSynthetic(true)
-        .setOrigin(FieldOrigin.SYNTHETIC_OUTER_FIELD)
-        .build();
-  }
-
   /** Creates a variable that matches a field definition. */
   private static Variable createParameterMatchingField(FieldDescriptor fieldDescriptor) {
     return Variable.newBuilder()

transpiler/javatests/com/google/j2cl/readable/java/anonymousinnerclass/output_wasm/module.wat.txt

@@ -70,9 +70,9 @@
   (field $vtable (ref $anonymousinnerclass.AnonymousInnerClass.1C.vtable))
   (field $itable (ref $itable))
   (field $f_$systemIdentityHashCode__java_lang_Object (mut i32))
+  (field $$captured_arg__anonymousinnerclass_AnonymousInnerClass_1C (mut i32))
   (field $$outer_this__anonymousinnerclass_AnonymousInnerClass_1C (mut (ref null $anonymousinnerclass.AnonymousInnerClass)))
   (field $f_fInC__anonymousinnerclass_AnonymousInnerClass_1C (mut i32))
-  (field $$captured_arg__anonymousinnerclass_AnonymousInnerClass_1C (mut i32))
   ))
  )
  (type $anonymousinnerclass.AnonymousInnerClass.1C.vtable (sub $java.lang.Object.vtable (struct
@@ -108,8 +108,8 @@
   (field $itable (ref $itable))
   (field $f_$systemIdentityHashCode__java_lang_Object (mut i32))
   (field $$outer_this__anonymousinnerclass_A_B (mut (ref null $anonymousinnerclass.A)))
-  (field $$outer_this__anonymousinnerclass_AnonymousInnerClass_2 (mut (ref null $anonymousinnerclass.AnonymousInnerClass)))
   (field $$captured_a__anonymousinnerclass_AnonymousInnerClass_2 (mut (ref null $anonymousinnerclass.A)))
+  (field $$outer_this__anonymousinnerclass_AnonymousInnerClass_2 (mut (ref null $anonymousinnerclass.AnonymousInnerClass)))
   ))
  )
  (type $anonymousinnerclass.AnonymousInnerClass.2.vtable (sub $anonymousinnerclass.A.B.vtable (struct
@@ -126,11 +126,11 @@
   (field $vtable (ref $anonymousinnerclass.AnonymousInnerClass.3.vtable))
   (field $itable (ref $itable))
   (field $f_$systemIdentityHashCode__java_lang_Object (mut i32))
+  (field $$captured_arg__anonymousinnerclass_AnonymousInnerClass_1C (mut i32))
   (field $$outer_this__anonymousinnerclass_AnonymousInnerClass_1C (mut (ref null $anonymousinnerclass.AnonymousInnerClass)))
   (field $f_fInC__anonymousinnerclass_AnonymousInnerClass_1C (mut i32))
-  (field $$captured_arg__anonymousinnerclass_AnonymousInnerClass_1C (mut i32))
-  (field $$outer_this__anonymousinnerclass_AnonymousInnerClass_3 (mut (ref null $anonymousinnerclass.AnonymousInnerClass)))
   (field $$captured_arg__anonymousinnerclass_AnonymousInnerClass_3 (mut i32))
+  (field $$outer_this__anonymousinnerclass_AnonymousInnerClass_3 (mut (ref null $anonymousinnerclass.AnonymousInnerClass)))
   ))
  )
  (type $anonymousinnerclass.AnonymousInnerClass.3.vtable (sub $anonymousinnerclass.AnonymousInnerClass.1C.vtable (struct
@@ -659,7 +659,7 @@
  (local $$instance (ref null $anonymousinnerclass.AnonymousInnerClass.1C))
  (block
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:30:10
-  (local.set $$instance (struct.new $anonymousinnerclass.AnonymousInnerClass.1C (ref.as_non_null (global.get $anonymousinnerclass.AnonymousInnerClass.1C.vtable)) (ref.as_non_null (global.get $itable.empty)) (i32.const 0) (ref.null $anonymousinnerclass.AnonymousInnerClass) (i32.const 0) (i32.const 0)))
+  (local.set $$instance (struct.new $anonymousinnerclass.AnonymousInnerClass.1C (ref.as_non_null (global.get $anonymousinnerclass.AnonymousInnerClass.1C.vtable)) (ref.as_non_null (global.get $itable.empty)) (i32.const 0) (i32.const 0) (ref.null $anonymousinnerclass.AnonymousInnerClass) (i32.const 0)))
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:30:10
   (call $$ctor__anonymousinnerclass_AnonymousInnerClass__int__void_$p_anonymousinnerclass_AnonymousInnerClass_1C@anonymousinnerclass.AnonymousInnerClass.1C (ref.as_non_null (local.get $$instance))(local.get $$outer_this)(local.get $$captured_arg))
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:30:10
@@ -855,7 +855,7 @@
  (local $$instance (ref null $anonymousinnerclass.AnonymousInnerClass.2))
  (block
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:29:21
-  (local.set $$instance (struct.new $anonymousinnerclass.AnonymousInnerClass.2 (ref.as_non_null (global.get $anonymousinnerclass.AnonymousInnerClass.2.vtable)) (ref.as_non_null (global.get $itable.empty)) (i32.const 0) (ref.null $anonymousinnerclass.A) (ref.null $anonymousinnerclass.AnonymousInnerClass) (ref.null $anonymousinnerclass.A)))
+  (local.set $$instance (struct.new $anonymousinnerclass.AnonymousInnerClass.2 (ref.as_non_null (global.get $anonymousinnerclass.AnonymousInnerClass.2.vtable)) (ref.as_non_null (global.get $itable.empty)) (i32.const 0) (ref.null $anonymousinnerclass.A) (ref.null $anonymousinnerclass.A) (ref.null $anonymousinnerclass.AnonymousInnerClass)))
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:29:21
   (call $$ctor__anonymousinnerclass_AnonymousInnerClass__anonymousinnerclass_A__void_$p_anonymousinnerclass_AnonymousInnerClass_2@anonymousinnerclass.AnonymousInnerClass.2 (ref.as_non_null (local.get $$instance))(local.get $$outer_this)(local.get $$captured_a))
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:29:21
@@ -949,7 +949,7 @@
  (local $$instance (ref null $anonymousinnerclass.AnonymousInnerClass.3))
  (block
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:33:18
-  (local.set $$instance (struct.new $anonymousinnerclass.AnonymousInnerClass.3 (ref.as_non_null (global.get $anonymousinnerclass.AnonymousInnerClass.3.vtable)) (ref.as_non_null (global.get $itable.empty)) (i32.const 0) (ref.null $anonymousinnerclass.AnonymousInnerClass) (i32.const 0) (i32.const 0) (ref.null $anonymousinnerclass.AnonymousInnerClass) (i32.const 0)))
+  (local.set $$instance (struct.new $anonymousinnerclass.AnonymousInnerClass.3 (ref.as_non_null (global.get $anonymousinnerclass.AnonymousInnerClass.3.vtable)) (ref.as_non_null (global.get $itable.empty)) (i32.const 0) (i32.const 0) (ref.null $anonymousinnerclass.AnonymousInnerClass) (i32.const 0) (i32.const 0) (ref.null $anonymousinnerclass.AnonymousInnerClass)))
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:33:18
   (call $$ctor__anonymousinnerclass_AnonymousInnerClass__int__void_$p_anonymousinnerclass_AnonymousInnerClass_3@anonymousinnerclass.AnonymousInnerClass.3 (ref.as_non_null (local.get $$instance))(local.get $$outer_this)(local.get $$captured_arg))
   ;;@ anonymousinnerclass/AnonymousInnerClass.java:33:18