Allow unboxing enums with multidimensional arrays
Bug: 185182242
Change-Id: Ieac93b60bf0474c6f3f1ca1ecbb14c6db7c09465
diff --git a/src/main/java/com/android/tools/r8/graph/DexItemFactory.java b/src/main/java/com/android/tools/r8/graph/DexItemFactory.java
index 6d57a75..ceb543f 100644
--- a/src/main/java/com/android/tools/r8/graph/DexItemFactory.java
+++ b/src/main/java/com/android/tools/r8/graph/DexItemFactory.java
@@ -390,6 +390,8 @@
public final DexType stringBuilderType = createStaticallyKnownType(stringBuilderDescriptor);
public final DexType stringBufferType = createStaticallyKnownType(stringBufferDescriptor);
+ public final DexType javaLangReflectArrayType =
+ createStaticallyKnownType("Ljava/lang/reflect/Array;");
public final DexType javaLangSystemType = createStaticallyKnownType(javaLangSystemDescriptor);
public final DexType javaIoPrintStreamType = createStaticallyKnownType("Ljava/io/PrintStream;");
@@ -557,6 +559,8 @@
public final ClassMethods classMethods = new ClassMethods();
public final ConstructorMethods constructorMethods = new ConstructorMethods();
public final EnumMembers enumMembers = new EnumMembers();
+ public final JavaLangReflectArrayMembers javaLangReflectArrayMembers =
+ new JavaLangReflectArrayMembers();
public final JavaLangSystemMethods javaLangSystemMethods = new JavaLangSystemMethods();
public final NullPointerExceptionMethods npeMethods = new NullPointerExceptionMethods();
public final IllegalArgumentExceptionMethods illegalArgumentExceptionMethods =
@@ -1453,6 +1457,17 @@
}
}
+ public class JavaLangReflectArrayMembers {
+
+ public final DexMethod newInstanceMethodWithDimensions =
+ createMethod(
+ javaLangReflectArrayType,
+ createProto(objectType, classType, intArrayType),
+ "newInstance");
+
+ private JavaLangReflectArrayMembers() {}
+ }
+
public class JavaLangSystemMethods {
public final DexMethod identityHashCode;
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/enums/EnumUnboxer.java b/src/main/java/com/android/tools/r8/ir/optimize/enums/EnumUnboxer.java
index cc7c72d..dc34e88 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/enums/EnumUnboxer.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/enums/EnumUnboxer.java
@@ -285,6 +285,19 @@
}
private void analyzeCheckCast(CheckCast checkCast, Set<DexType> eligibleEnums) {
+ // Casts to enum array types are fine as long all enum array creations are valid and have valid
+ // usages. Since creations of enum arrays are rewritten to primitive int arrays, enum array
+ // casts will continue to work after rewriting to int[] casts. Casts that failed with
+ // ClassCastException: "T[] cannot be cast to MyEnum[]" will continue to fail, but with "T[]
+ // cannot be cast to int[]".
+ //
+ // Note that strictly speaking, the rewriting from MyEnum[] to int[] could change the semantics
+ // of code that would fail with "int[] cannot be cast to MyEnum[]" in the input. However, javac
+ // does not allow such code ("incompatible types"), so we should generally not see such code.
+ if (checkCast.getType().isArrayType()) {
+ return;
+ }
+
// We are doing a type check, which typically means the in-value is of an upper
// type and cannot be dealt with.
// If the cast is on a dynamically typed object, the checkCast can be simply removed.
@@ -311,6 +324,9 @@
ConstClass constClass, Set<DexType> eligibleEnums, ProgramMethod context) {
// We are using the ConstClass of an enum, which typically means the enum cannot be unboxed.
// We however allow unboxing if the ConstClass is used only:
+ // - as an argument to java.lang.reflect.Array#newInstance(java.lang.Class, int[]), to allow
+ // unboxing of:
+ // MyEnum[][] a = new MyEnum[x][y];
// - as an argument to Enum#valueOf, to allow unboxing of:
// MyEnum a = Enum.valueOf(MyEnum.class, "A");
// - as a receiver for a name method, to allow unboxing of:
@@ -335,11 +351,18 @@
}
if (user.isInvokeStatic()) {
DexClassAndMethod singleTarget = user.asInvokeStatic().lookupSingleTarget(appView, context);
- if (singleTarget != null && singleTarget.getReference() == factory.enumMembers.valueOf) {
- // The name data is required for the correct mapping from the enum name to the ordinal in
- // the valueOf utility method.
- addRequiredNameData(enumType);
- continue;
+ if (singleTarget != null) {
+ if (singleTarget.getReference() == factory.enumMembers.valueOf) {
+ // The name data is required for the correct mapping from the enum name to the ordinal
+ // in
+ // the valueOf utility method.
+ addRequiredNameData(enumType);
+ continue;
+ }
+ if (singleTarget.getReference()
+ == factory.javaLangReflectArrayMembers.newInstanceMethodWithDimensions) {
+ continue;
+ }
}
}
markEnumAsUnboxable(Reason.CONST_CLASS, enumClass);
diff --git a/src/test/java/com/android/tools/r8/enumunboxing/EnumUnboxingArrayTest.java b/src/test/java/com/android/tools/r8/enumunboxing/EnumUnboxingArrayTest.java
index 2d5ddc0..4776d5f 100644
--- a/src/test/java/com/android/tools/r8/enumunboxing/EnumUnboxingArrayTest.java
+++ b/src/test/java/com/android/tools/r8/enumunboxing/EnumUnboxingArrayTest.java
@@ -53,14 +53,12 @@
.addOptionsModification(opt -> enableEnumOptions(opt, enumValueOptimization))
.addEnumUnboxingInspector(
inspector ->
- inspector
- .assertUnboxed(
- EnumArrayNullRead.MyEnum.class,
- EnumArrayReadWrite.MyEnum.class,
- EnumArrayReadWriteNoEscape.MyEnum.class,
- EnumVarArgs.MyEnum.class)
- // TODO(b/185182242): Should always be unboxed.
- .assertNotUnboxed(Enum2DimArrayReadWrite.MyEnum.class))
+ inspector.assertUnboxed(
+ Enum2DimArrayReadWrite.MyEnum.class,
+ EnumArrayNullRead.MyEnum.class,
+ EnumArrayReadWrite.MyEnum.class,
+ EnumArrayReadWriteNoEscape.MyEnum.class,
+ EnumVarArgs.MyEnum.class))
.setMinApi(parameters.getApiLevel())
.compile();
for (Class<?> main : TESTS) {
