[GR-32865] Automatic initialization of classes must use devirtualized callee.

PullRequest: graal/9452

Author: Christian Wimmer

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/classinitialization/TypeInitializerGraph.java

@@ -217,8 +217,19 @@ private boolean updateMethodSafety(AnalysisMethod m) {
      * Invoke becomes unsafe if it calls other unsafe methods.
      */
     private boolean isInvokeUnsafeIterative(InvokeTypeFlow i) {
-        assert i.getTargetMethod() != null : "All methods can be statically bound.";
-        return methodSafety.get(i.getTargetMethod()) == Safety.UNSAFE;
+        /*
+         * Note that even though (for now) we only process invokes that can be statically bound, we
+         * cannot just take the target method of the type flow: the static analysis can
+         * de-virtualize the target method to a method overridden in a subclass. So we must look at
+         * the actual callees of the type flow, even though we know that there is at most one callee
+         * returned.
+         */
+        for (AnalysisMethod callee : i.getCallees()) {
+            if (methodSafety.get(callee) == Safety.UNSAFE) {
+                return true;
+            }
+        }
+        return false;
     }
 
     private void addInitializer(AnalysisType t) {

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/clinit/TestClassInitializationMustBeSafeEarly.java

@@ -404,6 +404,47 @@ class ForNameMustBeDelayed {
     int field;
 }
 
+class DevirtualizedCallMustBeDelayed {
+    static {
+        System.out.println("Delaying " + DevirtualizedCallMustBeDelayed.class);
+    }
+
+    static final Object value = 42;
+}
+
+class DevirtualizedCallSuperMustBeSafeEarly {
+    Object foo() {
+        return -1;
+    }
+}
+
+class DevirtualizedCallSubMustBeSafeEarly extends DevirtualizedCallSuperMustBeSafeEarly {
+    @Override
+    Object foo() {
+        return DevirtualizedCallMustBeDelayed.value;
+    }
+}
+
+class DevirtualizedCallUsageMustBeDelayed {
+    static final Object value = computeValue();
+
+    private static Object computeValue() {
+        DevirtualizedCallSuperMustBeSafeEarly provider = createProvider();
+
+        /*
+         * The static analysis can prove that DevirtualizedCallSubMustBeDelayed.foo is the only
+         * callee and de-virtualize this call. So the original target method of the call site and
+         * the actually invoked method are different - and the analysis that automatically
+         * initializes classes must properly pick up this dependency.
+         */
+        return provider.foo();
+    }
+
+    private static DevirtualizedCallSuperMustBeSafeEarly createProvider() {
+        return new DevirtualizedCallSubMustBeSafeEarly();
+    }
+}
+
 class TestClassInitializationMustBeSafeEarlyFeature implements Feature {
 
     static final Class<?>[] checkedClasses = new Class<?>[]{
@@ -435,7 +476,8 @@ class TestClassInitializationMustBeSafeEarlyFeature implements Feature {
                     NativeMethodMustBeDelayed.class,
                     ReferencesOtherPureClassMustBeSafeEarly.class, HelperClassMustBeSafeEarly.class,
                     CycleMustBeSafeLate.class, HelperClassMustBeSafeLate.class,
-                    ReflectionMustBeSafeEarly.class, ForNameMustBeSafeEarly.class, ForNameMustBeDelayed.class
+                    ReflectionMustBeSafeEarly.class, ForNameMustBeSafeEarly.class, ForNameMustBeDelayed.class,
+                    DevirtualizedCallMustBeDelayed.class, DevirtualizedCallSuperMustBeSafeEarly.class, DevirtualizedCallSubMustBeSafeEarly.class, DevirtualizedCallUsageMustBeDelayed.class
     };
 
     private static void checkClasses(boolean checkSafeEarly, boolean checkSafeLate) {
@@ -611,6 +653,8 @@ public static void main(String[] args) {
         assertSame(ForNameMustBeDelayed.class, ReflectionMustBeSafeEarly.c2);
         assertSame("foo", ReflectionMustBeSafeEarly.m1.getName());
         assertSame("field", ReflectionMustBeSafeEarly.f2.getName());
+
+        System.out.println(DevirtualizedCallUsageMustBeDelayed.value);
     }
 
     private static void assertSame(Object expected, Object actual) {