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8255578: [JVMCI] be more careful about reflective reads of Class.componentType.

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Reviewed-by: kvn, dlong
This commit is contained in:
Tom Rodriguez 2020-11-02 19:19:48 +00:00
parent 05bcd67e65
commit bc6085b06c
3 changed files with 25 additions and 0 deletions
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2
src/hotspot/share/classfile/javaClasses.hpp
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@ -322,6 +322,8 @@ class java_lang_Class : AllStatic {
static oop class_data(oop java_class); static oop class_data(oop java_class);
static void set_class_data(oop java_class, oop classData); static void set_class_data(oop java_class, oop classData);
static int component_mirror_offset() { return _component_mirror_offset; }
static oop class_loader(oop java_class); static oop class_loader(oop java_class);
static void set_module(oop java_class, oop module); static void set_module(oop java_class, oop module);
static oop module(oop java_class); static oop module(oop java_class);

15
src/hotspot/share/jvmci/jvmciCompilerToVM.cpp
View file

@ -1995,6 +1995,14 @@ C2V_VMENTRY_NULL(jobject, readFieldValue, (JNIEnv* env, jobject, jobject object,
JVMCI_THROW_MSG_NULL(IllegalArgumentException, JVMCI_THROW_MSG_NULL(IllegalArgumentException,
err_msg("Unexpected type: %s", JVMCIENV->klass_name(base))); err_msg("Unexpected type: %s", JVMCIENV->klass_name(base)));
} }
if (displacement == java_lang_Class::component_mirror_offset() && java_lang_Class::is_instance(obj()) &&
!java_lang_Class::as_Klass(obj())->is_array_klass()) {
// Class.componentType for non-array classes can transiently contain an int[] that's
// used for locking so always return null to mimic Class.getComponentType()
return JVMCIENV->get_jobject(JVMCIENV->get_JavaConstant_NULL_POINTER());
}
jlong value = 0; jlong value = 0;
JVMCIObject kind; JVMCIObject kind;
switch (constant_type) { switch (constant_type) {
@ -2220,6 +2228,13 @@ C2V_VMENTRY_NULL(jobject, getObject, (JNIEnv* env, jobject, jobject x, long disp
JVMCI_THROW_0(NullPointerException); JVMCI_THROW_0(NullPointerException);
} }
Handle xobj = JVMCIENV->asConstant(JVMCIENV->wrap(x), JVMCI_CHECK_0); Handle xobj = JVMCIENV->asConstant(JVMCIENV->wrap(x), JVMCI_CHECK_0);
if (displacement == java_lang_Class::component_mirror_offset() && java_lang_Class::is_instance(xobj()) &&
!java_lang_Class::as_Klass(xobj())->is_array_klass()) {
// Class.componentType for non-array classes can transiently contain an int[] that's
// used for locking so always return null to mimic Class.getComponentType()
return JVMCIENV->get_jobject(JVMCIENV->get_JavaConstant_NULL_POINTER());
}
oop res = xobj->obj_field(displacement); oop res = xobj->obj_field(displacement);
JVMCIObject result = JVMCIENV->get_object_constant(res); JVMCIObject result = JVMCIENV->get_object_constant(res);
return JVMCIENV->get_jobject(result); return JVMCIENV->get_jobject(result);

8
src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotJDKReflection.java
View file

@ -404,6 +404,14 @@ final class HotSpotJDKReflection extends HotSpotJVMCIReflection {
assert obj != null; assert obj != null;
assert !field.isStatic() || obj instanceof Class; assert !field.isStatic() || obj instanceof Class;
long displacement = field.getOffset(); long displacement = field.getOffset();
if (obj instanceof Class && field.getName().equals("componentType")) {
Class<?> clazz = (Class<?>) obj;
if (!clazz.isArray()) {
// Class.componentType for non-array classes can transiently contain an int[] that's
// used for locking so always return null to mimic Class.getComponentType()
return JavaConstant.NULL_POINTER;
}
}
assert checkRead(field.getJavaKind(), displacement, assert checkRead(field.getJavaKind(), displacement,
(HotSpotResolvedObjectType) runtime().getHostJVMCIBackend().getMetaAccess().lookupJavaType(field.isStatic() ? (Class<?>) obj : obj.getClass()), (HotSpotResolvedObjectType) runtime().getHostJVMCIBackend().getMetaAccess().lookupJavaType(field.isStatic() ? (Class<?>) obj : obj.getClass()),