Merge "Avoid that class merging affects field resolution"
diff --git a/src/main/java/com/android/tools/r8/shaking/VerticalClassMerger.java b/src/main/java/com/android/tools/r8/shaking/VerticalClassMerger.java
index 5da6f06..4b57209 100644
--- a/src/main/java/com/android/tools/r8/shaking/VerticalClassMerger.java
+++ b/src/main/java/com/android/tools/r8/shaking/VerticalClassMerger.java
@@ -320,6 +320,11 @@
}
continue;
}
+ // Field resolution first considers the direct interfaces of [targetClass] before it proceeds
+ // to the super class.
+ if (fieldResolutionMayChange(clazz, targetClass)) {
+ continue;
+ }
// Guard against the case where we have two methods that may get the same signature
// if we replace types. This is rare, so we approximate and err on the safe side here.
if (new CollisionDetector(clazz.type, targetClass.type, getInvokes(), mergedClasses)
@@ -365,6 +370,35 @@
return renamedMembersLense.build(graphLense);
}
+ private boolean fieldResolutionMayChange(DexClass source, DexClass target) {
+ if (source.type == target.superType) {
+ // If there is a "iget Target.f" or "iput Target.f" instruction in target, and the class
+ // Target implements an interface that declares a static final field f, this should yield an
+ // IncompatibleClassChangeError.
+ // TODO(christofferqa): In the following we only check if a static field from an interface
+ // shadows an instance field from [source]. We could actually check if there is an iget/iput
+ // instruction whose resolution would be affected by the merge. The situation where a static
+ // field shadows an instance field is probably not widespread in practice, though.
+ FieldSignatureEquivalence equivalence = FieldSignatureEquivalence.get();
+ Set<Wrapper<DexField>> staticFieldsInInterfacesOfTarget = new HashSet<>();
+ for (DexType interfaceType : target.interfaces.values) {
+ DexClass clazz = appInfo.definitionFor(interfaceType);
+ for (DexEncodedField staticField : clazz.staticFields()) {
+ staticFieldsInInterfacesOfTarget.add(equivalence.wrap(staticField.field));
+ }
+ }
+ for (DexEncodedField instanceField : source.instanceFields()) {
+ if (staticFieldsInInterfacesOfTarget.contains(equivalence.wrap(instanceField.field))) {
+ // An instruction "iget Target.f" or "iput Target.f" that used to hit a static field in an
+ // interface would now hit an instance field from [source], so that an IncompatibleClass-
+ // ChangeError would no longer be thrown. Abort merge.
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
private class ClassMerger {
private static final String CONSTRUCTOR_NAME = "constructor";
