Gitiles
Code Review Sign In
LeafOS / LeafOS-Project / android_art / 11c8959243751f7a8946bae40f4346bc8d00cea4 / . / openjdkjvmti / ti_heap.cc
blob: 80bfa0ff433c3e532fc4016559613862111d99d5 [file] [log] [blame]
/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "ti_heap.h"
#include <ios>
#include <unordered_map>
#include "android-base/logging.h"
#include "android-base/thread_annotations.h"
#include "arch/context.h"
#include "art_field-inl.h"
#include "art_jvmti.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/mutex.h"
#include "base/utils.h"
#include "class_linker.h"
#include "deopt_manager.h"
#include "dex/primitive.h"
#include "events-inl.h"
#include "gc/collector_type.h"
#include "gc/gc_cause.h"
#include "gc/heap-visit-objects-inl.h"
#include "gc/heap-inl.h"
#include "gc/scoped_gc_critical_section.h"
#include "gc_root-inl.h"
#include "handle.h"
#include "handle_scope.h"
#include "java_frame_root_info.h"
#include "jni/jni_env_ext.h"
#include "jni/jni_id_manager.h"
#include "jni/jni_internal.h"
#include "jvmti_weak_table-inl.h"
#include "mirror/array-inl.h"
#include "mirror/array.h"
#include "mirror/class.h"
#include "mirror/object-inl.h"
#include "mirror/object-refvisitor-inl.h"
#include "mirror/object_array-inl.h"
#include "mirror/object_array-alloc-inl.h"
#include "mirror/object_reference.h"
#include "obj_ptr-inl.h"
#include "object_callbacks.h"
#include "object_tagging.h"
#include "offsets.h"
#include "read_barrier.h"
#include "runtime.h"
#include "scoped_thread_state_change-inl.h"
#include "stack.h"
#include "thread-inl.h"
#include "thread_list.h"
#include "ti_logging.h"
#include "ti_stack.h"
#include "ti_thread.h"
#include "well_known_classes.h"
namespace openjdkjvmti {
EventHandler* HeapExtensions::gEventHandler = nullptr;
namespace {
struct IndexCache {
// The number of interface fields implemented by the class. This is a prefix to all assigned
// field indices.
size_t interface_fields;
// It would be nice to also cache the following, but it is complicated to wire up into the
// generic visit:
// The number of fields in interfaces and superclasses. This is the first index assigned to
// fields of the class.
// size_t superclass_fields;
};
using IndexCachingTable = JvmtiWeakTable<IndexCache>;
static IndexCachingTable gIndexCachingTable;
// Report the contents of a string, if a callback is set.
jint ReportString(art::ObjPtr<art::mirror::Object> obj,
jvmtiEnv* env,
ObjectTagTable* tag_table,
const jvmtiHeapCallbacks* cb,
const void* user_data) REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (UNLIKELY(cb->string_primitive_value_callback != nullptr) && obj->IsString()) {
art::ObjPtr<art::mirror::String> str = obj->AsString();
int32_t string_length = str->GetLength();
JvmtiUniquePtr<uint16_t[]> data;
if (string_length > 0) {
jvmtiError alloc_error;
data = AllocJvmtiUniquePtr<uint16_t[]>(env, string_length, &alloc_error);
if (data == nullptr) {
// TODO: Not really sure what to do here. Should we abort the iteration and go all the way
// back? For now just warn.
LOG(WARNING) << "Unable to allocate buffer for string reporting! Silently dropping value."
<< " >" << str->ToModifiedUtf8() << "<";
return 0;
}
if (str->IsCompressed()) {
uint8_t* compressed_data = str->GetValueCompressed();
for (int32_t i = 0; i != string_length; ++i) {
data[i] = compressed_data[i];
}
} else {
// Can copy directly.
memcpy(data.get(), str->GetValue(), string_length * sizeof(uint16_t));
}
}
const jlong class_tag = tag_table->GetTagOrZero(obj->GetClass());
jlong string_tag = tag_table->GetTagOrZero(obj.Ptr());
const jlong saved_string_tag = string_tag;
jint result = cb->string_primitive_value_callback(class_tag,
obj->SizeOf(),
&string_tag,
data.get(),
string_length,
const_cast<void*>(user_data));
if (string_tag != saved_string_tag) {
tag_table->Set(obj.Ptr(), string_tag);
}
return result;
}
return 0;
}
// Report the contents of a primitive array, if a callback is set.
jint ReportPrimitiveArray(art::ObjPtr<art::mirror::Object> obj,
jvmtiEnv* env,
ObjectTagTable* tag_table,
const jvmtiHeapCallbacks* cb,
const void* user_data) REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (UNLIKELY(cb->array_primitive_value_callback != nullptr) &&
obj->IsArrayInstance() &&
!obj->IsObjectArray()) {
art::ObjPtr<art::mirror::Array> array = obj->AsArray();
int32_t array_length = array->GetLength();
size_t component_size = array->GetClass()->GetComponentSize();
art::Primitive::Type art_prim_type = array->GetClass()->GetComponentType()->GetPrimitiveType();
jvmtiPrimitiveType prim_type =
static_cast<jvmtiPrimitiveType>(art::Primitive::Descriptor(art_prim_type)[0]);
DCHECK(prim_type == JVMTI_PRIMITIVE_TYPE_BOOLEAN ||
prim_type == JVMTI_PRIMITIVE_TYPE_BYTE ||
prim_type == JVMTI_PRIMITIVE_TYPE_CHAR ||
prim_type == JVMTI_PRIMITIVE_TYPE_SHORT ||
prim_type == JVMTI_PRIMITIVE_TYPE_INT ||
prim_type == JVMTI_PRIMITIVE_TYPE_LONG ||
prim_type == JVMTI_PRIMITIVE_TYPE_FLOAT ||
prim_type == JVMTI_PRIMITIVE_TYPE_DOUBLE);
const jlong class_tag = tag_table->GetTagOrZero(obj->GetClass());
jlong array_tag = tag_table->GetTagOrZero(obj.Ptr());
const jlong saved_array_tag = array_tag;
jint result;
if (array_length == 0) {
result = cb->array_primitive_value_callback(class_tag,
obj->SizeOf(),
&array_tag,
0,
prim_type,
nullptr,
const_cast<void*>(user_data));
} else {
jvmtiError alloc_error;
JvmtiUniquePtr<char[]> data = AllocJvmtiUniquePtr<char[]>(env,
array_length * component_size,
&alloc_error);
if (data == nullptr) {
// TODO: Not really sure what to do here. Should we abort the iteration and go all the way
// back? For now just warn.
LOG(WARNING) << "Unable to allocate buffer for array reporting! Silently dropping value.";
return 0;
}
memcpy(data.get(), array->GetRawData(component_size, 0), array_length * component_size);
result = cb->array_primitive_value_callback(class_tag,
obj->SizeOf(),
&array_tag,
array_length,
prim_type,
data.get(),
const_cast<void*>(user_data));
}
if (array_tag != saved_array_tag) {
tag_table->Set(obj.Ptr(), array_tag);
}
return result;
}
return 0;
}
template <typename UserData>
bool VisitorFalse([[maybe_unused]] art::ObjPtr<art::mirror::Object> obj,
[[maybe_unused]] art::ObjPtr<art::mirror::Class> klass,
[[maybe_unused]] art::ArtField& field,
[[maybe_unused]] size_t field_index,
[[maybe_unused]] UserData* user_data) {
return false;
}
template <typename UserData, bool kCallVisitorOnRecursion>
class FieldVisitor {
public:
// Report the contents of a primitive fields of the given object, if a callback is set.
template <typename StaticPrimitiveVisitor,
typename StaticReferenceVisitor,
typename InstancePrimitiveVisitor,
typename InstanceReferenceVisitor>
static bool ReportFields(art::ObjPtr<art::mirror::Object> obj,
UserData* user_data,
StaticPrimitiveVisitor& static_prim_visitor,
StaticReferenceVisitor& static_ref_visitor,
InstancePrimitiveVisitor& instance_prim_visitor,
InstanceReferenceVisitor& instance_ref_visitor)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
FieldVisitor fv(user_data);
if (obj->IsClass()) {
// When visiting a class, we only visit the static fields of the given class. No field of
// superclasses is visited.
art::ObjPtr<art::mirror::Class> klass = obj->AsClass();
// Only report fields on resolved classes. We need valid field data.
if (!klass->IsResolved()) {
return false;
}
return fv.ReportFieldsImpl(nullptr,
obj->AsClass(),
obj->AsClass()->IsInterface(),
static_prim_visitor,
static_ref_visitor,
instance_prim_visitor,
instance_ref_visitor);
} else {
// See comment above. Just double-checking here, but an instance *should* mean the class was
// resolved.
DCHECK(obj->GetClass()->IsResolved() || obj->GetClass()->IsErroneousResolved());
return fv.ReportFieldsImpl(obj,
obj->GetClass(),
false,
static_prim_visitor,
static_ref_visitor,
instance_prim_visitor,
instance_ref_visitor);
}
}
private:
explicit FieldVisitor(UserData* user_data) : user_data_(user_data) {}
// Report the contents of fields of the given object. If obj is null, report the static fields,
// otherwise the instance fields.
template <typename StaticPrimitiveVisitor,
typename StaticReferenceVisitor,
typename InstancePrimitiveVisitor,
typename InstanceReferenceVisitor>
bool ReportFieldsImpl(art::ObjPtr<art::mirror::Object> obj,
art::ObjPtr<art::mirror::Class> klass,
bool skip_java_lang_object,
StaticPrimitiveVisitor& static_prim_visitor,
StaticReferenceVisitor& static_ref_visitor,
InstancePrimitiveVisitor& instance_prim_visitor,
InstanceReferenceVisitor& instance_ref_visitor)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
// Compute the offset of field indices.
size_t interface_field_count = CountInterfaceFields(klass);
size_t tmp;
bool aborted = ReportFieldsRecursive(obj,
klass,
interface_field_count,
skip_java_lang_object,
static_prim_visitor,
static_ref_visitor,
instance_prim_visitor,
instance_ref_visitor,
&tmp);
return aborted;
}
// Visit primitive fields in an object (instance). Return true if the visit was aborted.
template <typename StaticPrimitiveVisitor,
typename StaticReferenceVisitor,
typename InstancePrimitiveVisitor,
typename InstanceReferenceVisitor>
bool ReportFieldsRecursive(art::ObjPtr<art::mirror::Object> obj,
art::ObjPtr<art::mirror::Class> klass,
size_t interface_fields,
bool skip_java_lang_object,
StaticPrimitiveVisitor& static_prim_visitor,
StaticReferenceVisitor& static_ref_visitor,
InstancePrimitiveVisitor& instance_prim_visitor,
InstanceReferenceVisitor& instance_ref_visitor,
size_t* field_index_out)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
DCHECK(klass != nullptr);
size_t field_index;
if (klass->GetSuperClass() == nullptr) {
// j.l.Object. Start with the fields from interfaces.
field_index = interface_fields;
if (skip_java_lang_object) {
*field_index_out = field_index;
return false;
}
} else {
// Report superclass fields.
if (kCallVisitorOnRecursion) {
if (ReportFieldsRecursive(obj,
klass->GetSuperClass(),
interface_fields,
skip_java_lang_object,
static_prim_visitor,
static_ref_visitor,
instance_prim_visitor,
instance_ref_visitor,
&field_index)) {
return true;
}
} else {
// Still call, but with empty visitor. This is required for correct counting.
ReportFieldsRecursive(obj,
klass->GetSuperClass(),
interface_fields,
skip_java_lang_object,
VisitorFalse<UserData>,
VisitorFalse<UserData>,
VisitorFalse<UserData>,
VisitorFalse<UserData>,
&field_index);
}
}
// Now visit fields for the current klass.
for (auto& static_field : klass->GetSFields()) {
if (static_field.IsPrimitiveType()) {
if (static_prim_visitor(obj,
klass,
static_field,
field_index,
user_data_)) {
return true;
}
} else {
if (static_ref_visitor(obj,
klass,
static_field,
field_index,
user_data_)) {
return true;
}
}
field_index++;
}
for (auto& instance_field : klass->GetIFields()) {
if (instance_field.IsPrimitiveType()) {
if (instance_prim_visitor(obj,
klass,
instance_field,
field_index,
user_data_)) {
return true;
}
} else {
if (instance_ref_visitor(obj,
klass,
instance_field,
field_index,
user_data_)) {
return true;
}
}
field_index++;
}
*field_index_out = field_index;
return false;
}
// Implements a visit of the implemented interfaces of a given class.
template <typename T>
struct RecursiveInterfaceVisit {
static void VisitStatic(art::Thread* self, art::ObjPtr<art::mirror::Class> klass, T& visitor)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
RecursiveInterfaceVisit rv;
rv.Visit(self, klass, visitor);
}
void Visit(art::Thread* self, art::ObjPtr<art::mirror::Class> klass, T& visitor)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
// First visit the parent, to get the order right.
// (We do this in preparation for actual visiting of interface fields.)
if (klass->GetSuperClass() != nullptr) {
Visit(self, klass->GetSuperClass(), visitor);
}
for (uint32_t i = 0; i != klass->NumDirectInterfaces(); ++i) {
art::ObjPtr<art::mirror::Class> inf_klass = klass->GetDirectInterface(i);
DCHECK(inf_klass != nullptr);
VisitInterface(self, inf_klass, visitor);
}
}
void VisitInterface(art::Thread* self, art::ObjPtr<art::mirror::Class> inf_klass, T& visitor)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
auto it = visited_interfaces.find(inf_klass.Ptr());
if (it != visited_interfaces.end()) {
return;
}
visited_interfaces.insert(inf_klass.Ptr());
// Let the visitor know about this one. Note that this order is acceptable, as the ordering
// of these fields never matters for known visitors.
visitor(inf_klass);
// Now visit the superinterfaces.
for (uint32_t i = 0; i != inf_klass->NumDirectInterfaces(); ++i) {
art::ObjPtr<art::mirror::Class> super_inf_klass = inf_klass->GetDirectInterface(i);
DCHECK(super_inf_klass != nullptr);
VisitInterface(self, super_inf_klass, visitor);
}
}
std::unordered_set<art::mirror::Class*> visited_interfaces;
};
// Counting interface fields. Note that we cannot use the interface table, as that only contains
// "non-marker" interfaces (= interfaces with methods).
static size_t CountInterfaceFields(art::ObjPtr<art::mirror::Class> klass)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
// Do we have a cached value?
IndexCache tmp;
if (gIndexCachingTable.GetTag(klass.Ptr(), &tmp)) {
return tmp.interface_fields;
}
size_t count = 0;
auto visitor = [&count](art::ObjPtr<art::mirror::Class> inf_klass)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
DCHECK(inf_klass->IsInterface());
DCHECK_EQ(0u, inf_klass->NumInstanceFields());
count += inf_klass->NumStaticFields();
};
RecursiveInterfaceVisit<decltype(visitor)>::VisitStatic(art::Thread::Current(), klass, visitor);
// Store this into the cache.
tmp.interface_fields = count;
gIndexCachingTable.Set(klass.Ptr(), tmp);
return count;
}
UserData* user_data_;
};
// Debug helper. Prints the structure of an object.
template <bool kStatic, bool kRef>
struct DumpVisitor {
static bool Callback([[maybe_unused]] art::ObjPtr<art::mirror::Object> obj,
[[maybe_unused]] art::ObjPtr<art::mirror::Class> klass,
art::ArtField& field,
size_t field_index,
[[maybe_unused]] void* user_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
LOG(ERROR) << (kStatic ? "static " : "instance ")
<< (kRef ? "ref " : "primitive ")
<< field.PrettyField()
<< " @ "
<< field_index;
return false;
}
};
[[maybe_unused]] void DumpObjectFields(art::ObjPtr<art::mirror::Object> obj)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (obj->IsClass()) {
FieldVisitor<void, false>:: ReportFields(obj,
nullptr,
DumpVisitor<true, false>::Callback,
DumpVisitor<true, true>::Callback,
DumpVisitor<false, false>::Callback,
DumpVisitor<false, true>::Callback);
} else {
FieldVisitor<void, true>::ReportFields(obj,
nullptr,
DumpVisitor<true, false>::Callback,
DumpVisitor<true, true>::Callback,
DumpVisitor<false, false>::Callback,
DumpVisitor<false, true>::Callback);
}
}
class ReportPrimitiveField {
public:
static bool Report(art::ObjPtr<art::mirror::Object> obj,
ObjectTagTable* tag_table,
const jvmtiHeapCallbacks* cb,
const void* user_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (UNLIKELY(cb->primitive_field_callback != nullptr)) {
jlong class_tag = tag_table->GetTagOrZero(obj->GetClass());
ReportPrimitiveField rpf(tag_table, class_tag, cb, user_data);
if (obj->IsClass()) {
return FieldVisitor<ReportPrimitiveField, false>::ReportFields(
obj,
&rpf,
ReportPrimitiveFieldCallback<true>,
VisitorFalse<ReportPrimitiveField>,
VisitorFalse<ReportPrimitiveField>,
VisitorFalse<ReportPrimitiveField>);
} else {
return FieldVisitor<ReportPrimitiveField, true>::ReportFields(
obj,
&rpf,
VisitorFalse<ReportPrimitiveField>,
VisitorFalse<ReportPrimitiveField>,
ReportPrimitiveFieldCallback<false>,
VisitorFalse<ReportPrimitiveField>);
}
}
return false;
}
private:
ReportPrimitiveField(ObjectTagTable* tag_table,
jlong class_tag,
const jvmtiHeapCallbacks* cb,
const void* user_data)
: tag_table_(tag_table), class_tag_(class_tag), cb_(cb), user_data_(user_data) {}
template <bool kReportStatic>
static bool ReportPrimitiveFieldCallback(art::ObjPtr<art::mirror::Object> obj,
art::ObjPtr<art::mirror::Class> klass,
art::ArtField& field,
size_t field_index,
ReportPrimitiveField* user_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::Primitive::Type art_prim_type = field.GetTypeAsPrimitiveType();
jvmtiPrimitiveType prim_type =
static_cast<jvmtiPrimitiveType>(art::Primitive::Descriptor(art_prim_type)[0]);
DCHECK(prim_type == JVMTI_PRIMITIVE_TYPE_BOOLEAN ||
prim_type == JVMTI_PRIMITIVE_TYPE_BYTE ||
prim_type == JVMTI_PRIMITIVE_TYPE_CHAR ||
prim_type == JVMTI_PRIMITIVE_TYPE_SHORT ||
prim_type == JVMTI_PRIMITIVE_TYPE_INT ||
prim_type == JVMTI_PRIMITIVE_TYPE_LONG ||
prim_type == JVMTI_PRIMITIVE_TYPE_FLOAT ||
prim_type == JVMTI_PRIMITIVE_TYPE_DOUBLE);
jvmtiHeapReferenceInfo info;
info.field.index = field_index;
jvalue value;
memset(&value, 0, sizeof(jvalue));
art::ObjPtr<art::mirror::Object> src = kReportStatic ? klass : obj;
switch (art_prim_type) {
case art::Primitive::Type::kPrimBoolean:
value.z = field.GetBoolean(src) == 0 ? JNI_FALSE : JNI_TRUE;
break;
case art::Primitive::Type::kPrimByte:
value.b = field.GetByte(src);
break;
case art::Primitive::Type::kPrimChar:
value.c = field.GetChar(src);
break;
case art::Primitive::Type::kPrimShort:
value.s = field.GetShort(src);
break;
case art::Primitive::Type::kPrimInt:
value.i = field.GetInt(src);
break;
case art::Primitive::Type::kPrimLong:
value.j = field.GetLong(src);
break;
case art::Primitive::Type::kPrimFloat:
value.f = field.GetFloat(src);
break;
case art::Primitive::Type::kPrimDouble:
value.d = field.GetDouble(src);
break;
case art::Primitive::Type::kPrimVoid:
case art::Primitive::Type::kPrimNot: {
LOG(FATAL) << "Should not reach here";
UNREACHABLE();
}
}
jlong obj_tag = user_data->tag_table_->GetTagOrZero(src.Ptr());
const jlong saved_obj_tag = obj_tag;
jint ret = user_data->cb_->primitive_field_callback(kReportStatic
? JVMTI_HEAP_REFERENCE_STATIC_FIELD
: JVMTI_HEAP_REFERENCE_FIELD,
&info,
user_data->class_tag_,
&obj_tag,
value,
prim_type,
const_cast<void*>(user_data->user_data_));
if (saved_obj_tag != obj_tag) {
user_data->tag_table_->Set(src.Ptr(), obj_tag);
}
if ((ret & JVMTI_VISIT_ABORT) != 0) {
return true;
}
return false;
}
ObjectTagTable* tag_table_;
jlong class_tag_;
const jvmtiHeapCallbacks* cb_;
const void* user_data_;
};
struct HeapFilter {
explicit HeapFilter(jint heap_filter)
: filter_out_tagged((heap_filter & JVMTI_HEAP_FILTER_TAGGED) != 0),
filter_out_untagged((heap_filter & JVMTI_HEAP_FILTER_UNTAGGED) != 0),
filter_out_class_tagged((heap_filter & JVMTI_HEAP_FILTER_CLASS_TAGGED) != 0),
filter_out_class_untagged((heap_filter & JVMTI_HEAP_FILTER_CLASS_UNTAGGED) != 0),
any_filter(filter_out_tagged ||
filter_out_untagged ||
filter_out_class_tagged ||
filter_out_class_untagged) {
}
bool ShouldReportByHeapFilter(jlong tag, jlong class_tag) const {
if (!any_filter) {
return true;
}
if ((tag == 0 && filter_out_untagged) || (tag != 0 && filter_out_tagged)) {
return false;
}
if ((class_tag == 0 && filter_out_class_untagged) ||
(class_tag != 0 && filter_out_class_tagged)) {
return false;
}
return true;
}
const bool filter_out_tagged;
const bool filter_out_untagged;
const bool filter_out_class_tagged;
const bool filter_out_class_untagged;
const bool any_filter;
};
} // namespace
void HeapUtil::Register() {
art::Runtime::Current()->AddSystemWeakHolder(&gIndexCachingTable);
}
void HeapUtil::Unregister() {
art::Runtime::Current()->RemoveSystemWeakHolder(&gIndexCachingTable);
}
jvmtiError HeapUtil::IterateOverInstancesOfClass(jvmtiEnv* env,
jclass klass,
jvmtiHeapObjectFilter filter,
jvmtiHeapObjectCallback cb,
const void* user_data) {
if (cb == nullptr || klass == nullptr) {
return ERR(NULL_POINTER);
}
art::Thread* self = art::Thread::Current();
art::ScopedObjectAccess soa(self); // Now we know we have the shared lock.
art::StackHandleScope<1> hs(self);
art::ObjPtr<art::mirror::Object> klass_ptr(soa.Decode<art::mirror::Class>(klass));
if (!klass_ptr->IsClass()) {
return ERR(INVALID_CLASS);
}
art::Handle<art::mirror::Class> filter_klass(hs.NewHandle(klass_ptr->AsClass()));
ObjectTagTable* tag_table = ArtJvmTiEnv::AsArtJvmTiEnv(env)->object_tag_table.get();
bool stop_reports = false;
auto visitor = [&](art::mirror::Object* obj) REQUIRES_SHARED(art::Locks::mutator_lock_) {
// Early return, as we can't really stop visiting.
if (stop_reports) {
return;
}
art::ScopedAssertNoThreadSuspension no_suspension("IterateOverInstancesOfClass");
art::ObjPtr<art::mirror::Class> klass = obj->GetClass();
if (filter_klass != nullptr && !filter_klass->IsAssignableFrom(klass)) {
return;
}
jlong tag = 0;
tag_table->GetTag(obj, &tag);
if ((filter != JVMTI_HEAP_OBJECT_EITHER) &&
((tag == 0 && filter == JVMTI_HEAP_OBJECT_TAGGED) ||
(tag != 0 && filter == JVMTI_HEAP_OBJECT_UNTAGGED))) {
return;
}
jlong class_tag = 0;
tag_table->GetTag(klass.Ptr(), &class_tag);
jlong saved_tag = tag;
jint ret = cb(class_tag, obj->SizeOf(), &tag, const_cast<void*>(user_data));
stop_reports = (ret == JVMTI_ITERATION_ABORT);
if (tag != saved_tag) {
tag_table->Set(obj, tag);
}
};
art::Runtime::Current()->GetHeap()->VisitObjects(visitor);
return OK;
}
template <typename T>
static jvmtiError DoIterateThroughHeap(T fn,
jvmtiEnv* env,
ObjectTagTable* tag_table,
jint heap_filter_int,
jclass klass,
const jvmtiHeapCallbacks* callbacks,
const void* user_data) {
if (callbacks == nullptr) {
return ERR(NULL_POINTER);
}
art::Thread* self = art::Thread::Current();
art::ScopedObjectAccess soa(self); // Now we know we have the shared lock.
bool stop_reports = false;
const HeapFilter heap_filter(heap_filter_int);
art::StackHandleScope<1> hs(self);
art::Handle<art::mirror::Class> filter_klass(hs.NewHandle(soa.Decode<art::mirror::Class>(klass)));
auto visitor = [&](art::mirror::Object* obj) REQUIRES_SHARED(art::Locks::mutator_lock_) {
// Early return, as we can't really stop visiting.
if (stop_reports) {
return;
}
art::ScopedAssertNoThreadSuspension no_suspension("IterateThroughHeapCallback");
jlong tag = 0;
tag_table->GetTag(obj, &tag);
jlong class_tag = 0;
art::ObjPtr<art::mirror::Class> klass = obj->GetClass();
tag_table->GetTag(klass.Ptr(), &class_tag);
// For simplicity, even if we find a tag = 0, assume 0 = not tagged.
if (!heap_filter.ShouldReportByHeapFilter(tag, class_tag)) {
return;
}
if (filter_klass != nullptr) {
if (filter_klass.Get() != klass) {
return;
}
}
jlong size = obj->SizeOf();
jint length = -1;
if (obj->IsArrayInstance()) {
length = obj->AsArray()->GetLength();
}
jlong saved_tag = tag;
jint ret = fn(obj, callbacks, class_tag, size, &tag, length, const_cast<void*>(user_data));
if (tag != saved_tag) {
tag_table->Set(obj, tag);
}
stop_reports = (ret & JVMTI_VISIT_ABORT) != 0;
if (!stop_reports) {
jint string_ret = ReportString(obj, env, tag_table, callbacks, user_data);
stop_reports = (string_ret & JVMTI_VISIT_ABORT) != 0;
}
if (!stop_reports) {
jint array_ret = ReportPrimitiveArray(obj, env, tag_table, callbacks, user_data);
stop_reports = (array_ret & JVMTI_VISIT_ABORT) != 0;
}
if (!stop_reports) {
stop_reports = ReportPrimitiveField::Report(obj, tag_table, callbacks, user_data);
}
};
art::Runtime::Current()->GetHeap()->VisitObjects(visitor);
return ERR(NONE);
}
jvmtiError HeapUtil::IterateThroughHeap(jvmtiEnv* env,
jint heap_filter,
jclass klass,
const jvmtiHeapCallbacks* callbacks,
const void* user_data) {
auto JvmtiIterateHeap = []([[maybe_unused]] art::mirror::Object* obj,
const jvmtiHeapCallbacks* cb_callbacks,
jlong class_tag,
jlong size,
jlong* tag,
jint length,
void* cb_user_data) REQUIRES_SHARED(art::Locks::mutator_lock_) {
return cb_callbacks->heap_iteration_callback(class_tag,
size,
tag,
length,
cb_user_data);
};
return DoIterateThroughHeap(JvmtiIterateHeap,
env,
ArtJvmTiEnv::AsArtJvmTiEnv(env)->object_tag_table.get(),
heap_filter,
klass,
callbacks,
user_data);
}
class FollowReferencesHelper final {
public:
FollowReferencesHelper(HeapUtil* h,
jvmtiEnv* jvmti_env,
art::ObjPtr<art::mirror::Object> initial_object,
const jvmtiHeapCallbacks* callbacks,
art::ObjPtr<art::mirror::Class> class_filter,
jint heap_filter,
const void* user_data)
: env(jvmti_env),
tag_table_(h->GetTags()),
initial_object_(initial_object),
callbacks_(callbacks),
class_filter_(class_filter),
heap_filter_(heap_filter),
user_data_(user_data),
start_(0),
stop_reports_(false) {
}
void Init()
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
if (initial_object_.IsNull()) {
CollectAndReportRootsVisitor carrv(this, tag_table_, &worklist_, &visited_);
// We need precise info (e.g., vregs).
constexpr art::VisitRootFlags kRootFlags = static_cast<art::VisitRootFlags>(
art::VisitRootFlags::kVisitRootFlagAllRoots | art::VisitRootFlags::kVisitRootFlagPrecise);
art::Runtime::Current()->VisitRoots(&carrv, kRootFlags);
art::Runtime::Current()->VisitImageRoots(&carrv);
stop_reports_ = carrv.IsStopReports();
if (stop_reports_) {
worklist_.clear();
}
} else {
visited_.insert(initial_object_.Ptr());
worklist_.push_back(initial_object_.Ptr());
}
}
void Work()
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
// Currently implemented as a BFS. To lower overhead, we don't erase elements immediately
// from the head of the work list, instead postponing until there's a gap that's "large."
//
// Alternatively, we can implement a DFS and use the work list as a stack.
while (start_ < worklist_.size()) {
art::mirror::Object* cur_obj = worklist_[start_];
start_++;
if (start_ >= kMaxStart) {
worklist_.erase(worklist_.begin(), worklist_.begin() + start_);
start_ = 0;
}
VisitObject(cur_obj);
if (stop_reports_) {
break;
}
}
}
private:
class CollectAndReportRootsVisitor final : public art::RootVisitor {
public:
CollectAndReportRootsVisitor(FollowReferencesHelper* helper,
ObjectTagTable* tag_table,
std::vector<art::mirror::Object*>* worklist,
std::unordered_set<art::mirror::Object*>* visited)
: helper_(helper),
tag_table_(tag_table),
worklist_(worklist),
visited_(visited),
stop_reports_(false) {}
void VisitRoots(art::mirror::Object*** roots, size_t count, const art::RootInfo& info)
override
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*helper_->tag_table_->GetAllowDisallowLock()) {
for (size_t i = 0; i != count; ++i) {
AddRoot(*roots[i], info);
}
}
void VisitRoots(art::mirror::CompressedReference<art::mirror::Object>** roots,
size_t count,
const art::RootInfo& info)
override REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*helper_->tag_table_->GetAllowDisallowLock()) {
for (size_t i = 0; i != count; ++i) {
AddRoot(roots[i]->AsMirrorPtr(), info);
}
}
bool IsStopReports() {
return stop_reports_;
}
private:
void AddRoot(art::mirror::Object* root_obj, const art::RootInfo& info)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
if (stop_reports_) {
return;
}
bool add_to_worklist = ReportRoot(root_obj, info);
// We use visited_ to mark roots already so we do not need another set.
if (visited_->find(root_obj) == visited_->end()) {
if (add_to_worklist) {
visited_->insert(root_obj);
worklist_->push_back(root_obj);
}
}
}
// Remove NO_THREAD_SAFETY_ANALYSIS once ASSERT_CAPABILITY works correctly.
art::Thread* FindThread(const art::RootInfo& info) NO_THREAD_SAFETY_ANALYSIS {
art::Locks::thread_list_lock_->AssertExclusiveHeld(art::Thread::Current());
return art::Runtime::Current()->GetThreadList()->FindThreadByThreadId(info.GetThreadId());
}
jvmtiHeapReferenceKind GetReferenceKind(const art::RootInfo& info,
jvmtiHeapReferenceInfo* ref_info)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
// We do not necessarily hold thread_list_lock_ here, but we may if we are called from
// VisitThreadRoots, which can happen from JVMTI FollowReferences. If it was acquired in
// ThreadList::VisitRoots, it's unsafe to temporarily release it. Thus we act as if we did
// not hold the thread_list_lock_ here, and relax CHECKs appropriately. If it does happen,
// we are in a SuspendAll situation with concurrent GC disabled, and should not need to run
// flip functions. TODO: Find a way to clean this up.
// TODO: Fill in ref_info.
memset(ref_info, 0, sizeof(jvmtiHeapReferenceInfo));
switch (info.GetType()) {
case art::RootType::kRootJNIGlobal:
return JVMTI_HEAP_REFERENCE_JNI_GLOBAL;
case art::RootType::kRootJNILocal:
{
uint32_t thread_id = info.GetThreadId();
ref_info->jni_local.thread_id = thread_id;
art::Thread* thread = FindThread(info);
if (thread != nullptr) {
art::mirror::Object* thread_obj;
if (thread->IsStillStarting()) {
thread_obj = nullptr;
} else {
thread_obj = thread->GetPeerFromOtherThread();
}
if (thread_obj != nullptr) {
ref_info->jni_local.thread_tag = tag_table_->GetTagOrZero(thread_obj);
}
}
// TODO: We don't have this info.
if (thread != nullptr) {
ref_info->jni_local.depth = 0;
art::ArtMethod* method = thread->GetCurrentMethod(nullptr,
/* check_suspended= */ true,
/* abort_on_error= */ false);
if (method != nullptr) {
ref_info->jni_local.method = art::jni::EncodeArtMethod(method);
}
}
return JVMTI_HEAP_REFERENCE_JNI_LOCAL;
}
case art::RootType::kRootJavaFrame:
{
uint32_t thread_id = info.GetThreadId();
ref_info->stack_local.thread_id = thread_id;
art::Thread* thread = FindThread(info);
if (thread != nullptr) {
art::mirror::Object* thread_obj;
if (thread->IsStillStarting()) {
thread_obj = nullptr;
} else {
thread_obj = thread->GetPeerFromOtherThread();
}
if (thread_obj != nullptr) {
ref_info->stack_local.thread_tag = tag_table_->GetTagOrZero(thread_obj);
}
}
auto& java_info = static_cast<const art::JavaFrameRootInfo&>(info);
size_t vreg = java_info.GetVReg();
ref_info->stack_local.slot = static_cast<jint>(
vreg <= art::JavaFrameRootInfo::kMaxVReg ? vreg : -1);
const art::StackVisitor* visitor = java_info.GetVisitor();
ref_info->stack_local.location =
static_cast<jlocation>(visitor->GetDexPc(/* abort_on_failure= */ false));
ref_info->stack_local.depth = static_cast<jint>(visitor->GetFrameDepth());
art::ArtMethod* method = visitor->GetMethod();
if (method != nullptr) {
ref_info->stack_local.method = art::jni::EncodeArtMethod(method);
}
return JVMTI_HEAP_REFERENCE_STACK_LOCAL;
}
case art::RootType::kRootNativeStack:
case art::RootType::kRootThreadBlock:
case art::RootType::kRootThreadObject:
return JVMTI_HEAP_REFERENCE_THREAD;
case art::RootType::kRootStickyClass:
case art::RootType::kRootInternedString:
// Note: this isn't a root in the RI.
return JVMTI_HEAP_REFERENCE_SYSTEM_CLASS;
case art::RootType::kRootMonitorUsed:
case art::RootType::kRootJNIMonitor:
return JVMTI_HEAP_REFERENCE_MONITOR;
case art::RootType::kRootFinalizing:
case art::RootType::kRootDebugger:
case art::RootType::kRootReferenceCleanup:
case art::RootType::kRootVMInternal:
case art::RootType::kRootUnknown:
return JVMTI_HEAP_REFERENCE_OTHER;
}
LOG(FATAL) << "Unreachable";
UNREACHABLE();
}
bool ReportRoot(art::mirror::Object* root_obj, const art::RootInfo& info)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
jvmtiHeapReferenceInfo ref_info;
jvmtiHeapReferenceKind kind = GetReferenceKind(info, &ref_info);
jint result = helper_->ReportReference(kind, &ref_info, nullptr, root_obj);
if ((result & JVMTI_VISIT_ABORT) != 0) {
stop_reports_ = true;
}
return (result & JVMTI_VISIT_OBJECTS) != 0;
}
private:
FollowReferencesHelper* helper_;
ObjectTagTable* tag_table_;
std::vector<art::mirror::Object*>* worklist_;
std::unordered_set<art::mirror::Object*>* visited_;
bool stop_reports_;
};
void VisitObject(art::mirror::Object* obj)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
if (obj->IsClass()) {
VisitClass(obj->AsClass().Ptr());
return;
}
if (obj->IsArrayInstance()) {
VisitArray(obj);
return;
}
// All instance fields.
auto report_instance_field =
[&](art::ObjPtr<art::mirror::Object> src,
[[maybe_unused]] art::ObjPtr<art::mirror::Class> obj_klass,
art::ArtField& field,
size_t field_index,
[[maybe_unused]] void* user_data) REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
art::ObjPtr<art::mirror::Object> field_value = field.GetObject(src);
if (field_value != nullptr) {
jvmtiHeapReferenceInfo reference_info;
memset(&reference_info, 0, sizeof(reference_info));
reference_info.field.index = field_index;
jvmtiHeapReferenceKind kind =
field.GetOffset().Int32Value() ==
art::mirror::Object::ClassOffset().Int32Value() ?
JVMTI_HEAP_REFERENCE_CLASS :
JVMTI_HEAP_REFERENCE_FIELD;
const jvmtiHeapReferenceInfo* reference_info_ptr =
kind == JVMTI_HEAP_REFERENCE_CLASS ? nullptr : &reference_info;
return !ReportReferenceMaybeEnqueue(
kind, reference_info_ptr, src.Ptr(), field_value.Ptr());
}
return false;
};
stop_reports_ = FieldVisitor<void, true>::ReportFields(obj,
nullptr,
VisitorFalse<void>,
VisitorFalse<void>,
VisitorFalse<void>,
report_instance_field);
if (stop_reports_) {
return;
}
jint string_ret = ReportString(obj, env, tag_table_, callbacks_, user_data_);
stop_reports_ = (string_ret & JVMTI_VISIT_ABORT) != 0;
if (stop_reports_) {
return;
}
stop_reports_ = ReportPrimitiveField::Report(obj, tag_table_, callbacks_, user_data_);
}
void VisitArray(art::mirror::Object* array)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
stop_reports_ = !ReportReferenceMaybeEnqueue(JVMTI_HEAP_REFERENCE_CLASS,
nullptr,
array,
array->GetClass());
if (stop_reports_) {
return;
}
if (array->IsObjectArray()) {
art::ObjPtr<art::mirror::ObjectArray<art::mirror::Object>> obj_array =
array->AsObjectArray<art::mirror::Object>();
for (auto elem_pair : art::ZipCount(obj_array->Iterate())) {
if (elem_pair.first != nullptr) {
jvmtiHeapReferenceInfo reference_info;
reference_info.array.index = elem_pair.second;
stop_reports_ = !ReportReferenceMaybeEnqueue(JVMTI_HEAP_REFERENCE_ARRAY_ELEMENT,
&reference_info,
array,
elem_pair.first.Ptr());
if (stop_reports_) {
break;
}
}
}
} else {
if (!stop_reports_) {
jint array_ret = ReportPrimitiveArray(array, env, tag_table_, callbacks_, user_data_);
stop_reports_ = (array_ret & JVMTI_VISIT_ABORT) != 0;
}
}
}
void VisitClass(art::mirror::Class* klass)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
// TODO: Are erroneous classes reported? Are non-prepared ones? For now, just use resolved ones.
if (!klass->IsResolved()) {
return;
}
// Superclass.
stop_reports_ = !ReportReferenceMaybeEnqueue(JVMTI_HEAP_REFERENCE_SUPERCLASS,
nullptr,
klass,
klass->GetSuperClass().Ptr());
if (stop_reports_) {
return;
}
// Directly implemented or extended interfaces.
art::Thread* self = art::Thread::Current();
art::StackHandleScope<1> hs(self);
art::Handle<art::mirror::Class> h_klass(hs.NewHandle<art::mirror::Class>(klass));
for (size_t i = 0; i < h_klass->NumDirectInterfaces(); ++i) {
art::ObjPtr<art::mirror::Class> inf_klass =
art::mirror::Class::ResolveDirectInterface(self, h_klass, i);
if (inf_klass == nullptr) {
// TODO: With a resolved class this should not happen...
self->ClearException();
break;
}
stop_reports_ = !ReportReferenceMaybeEnqueue(JVMTI_HEAP_REFERENCE_INTERFACE,
nullptr,
klass,
inf_klass.Ptr());
if (stop_reports_) {
return;
}
}
// Classloader.
// TODO: What about the boot classpath loader? We'll skip for now, but do we have to find the
// fake BootClassLoader?
if (klass->GetClassLoader() != nullptr) {
stop_reports_ = !ReportReferenceMaybeEnqueue(JVMTI_HEAP_REFERENCE_CLASS_LOADER,
nullptr,
klass,
klass->GetClassLoader().Ptr());
if (stop_reports_) {
return;
}
}
DCHECK_EQ(h_klass.Get(), klass);
// Declared static fields.
auto report_static_field =
[&]([[maybe_unused]] art::ObjPtr<art::mirror::Object> obj,
art::ObjPtr<art::mirror::Class> obj_klass,
art::ArtField& field,
size_t field_index,
[[maybe_unused]] void* user_data) REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
art::ObjPtr<art::mirror::Object> field_value = field.GetObject(obj_klass);
if (field_value != nullptr) {
jvmtiHeapReferenceInfo reference_info;
memset(&reference_info, 0, sizeof(reference_info));
reference_info.field.index = static_cast<jint>(field_index);
return !ReportReferenceMaybeEnqueue(JVMTI_HEAP_REFERENCE_STATIC_FIELD,
&reference_info,
obj_klass.Ptr(),
field_value.Ptr());
}
return false;
};
stop_reports_ = FieldVisitor<void, false>::ReportFields(klass,
nullptr,
VisitorFalse<void>,
report_static_field,
VisitorFalse<void>,
VisitorFalse<void>);
if (stop_reports_) {
return;
}
stop_reports_ = ReportPrimitiveField::Report(klass, tag_table_, callbacks_, user_data_);
}
void MaybeEnqueue(art::mirror::Object* obj) REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (visited_.find(obj) == visited_.end()) {
worklist_.push_back(obj);
visited_.insert(obj);
}
}
bool ReportReferenceMaybeEnqueue(jvmtiHeapReferenceKind kind,
const jvmtiHeapReferenceInfo* reference_info,
art::mirror::Object* referree,
art::mirror::Object* referrer)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
jint result = ReportReference(kind, reference_info, referree, referrer);
if ((result & JVMTI_VISIT_ABORT) == 0) {
if ((result & JVMTI_VISIT_OBJECTS) != 0) {
MaybeEnqueue(referrer);
}
return true;
} else {
return false;
}
}
jint ReportReference(jvmtiHeapReferenceKind kind,
const jvmtiHeapReferenceInfo* reference_info,
art::mirror::Object* referrer,
art::mirror::Object* referree)
REQUIRES_SHARED(art::Locks::mutator_lock_)
REQUIRES(!*tag_table_->GetAllowDisallowLock()) {
if (referree == nullptr || stop_reports_) {
return 0;
}
if (UNLIKELY(class_filter_ != nullptr) && class_filter_ != referree->GetClass()) {
return JVMTI_VISIT_OBJECTS;
}
const jlong class_tag = tag_table_->GetTagOrZero(referree->GetClass());
jlong tag = tag_table_->GetTagOrZero(referree);
if (!heap_filter_.ShouldReportByHeapFilter(tag, class_tag)) {
return JVMTI_VISIT_OBJECTS;
}
const jlong referrer_class_tag =
referrer == nullptr ? 0 : tag_table_->GetTagOrZero(referrer->GetClass());
const jlong size = static_cast<jlong>(referree->SizeOf());
jlong saved_tag = tag;
jlong referrer_tag = 0;
jlong saved_referrer_tag = 0;
jlong* referrer_tag_ptr;
if (referrer == nullptr) {
referrer_tag_ptr = nullptr;
} else {
if (referrer == referree) {
referrer_tag_ptr = &tag;
} else {
referrer_tag = saved_referrer_tag = tag_table_->GetTagOrZero(referrer);
referrer_tag_ptr = &referrer_tag;
}
}
jint length = -1;
if (referree->IsArrayInstance()) {
length = referree->AsArray()->GetLength();
}
jint result = callbacks_->heap_reference_callback(kind,
reference_info,
class_tag,
referrer_class_tag,
size,
&tag,
referrer_tag_ptr,
length,
const_cast<void*>(user_data_));
if (tag != saved_tag) {
tag_table_->Set(referree, tag);
}
if (referrer_tag != saved_referrer_tag) {
tag_table_->Set(referrer, referrer_tag);
}
return result;
}
jvmtiEnv* env;
ObjectTagTable* tag_table_;
art::ObjPtr<art::mirror::Object> initial_object_;
const jvmtiHeapCallbacks* callbacks_;
art::ObjPtr<art::mirror::Class> class_filter_;
const HeapFilter heap_filter_;
const void* user_data_;
std::vector<art::mirror::Object*> worklist_;
size_t start_;
static constexpr size_t kMaxStart = 1000000U;
std::unordered_set<art::mirror::Object*> visited_;
bool stop_reports_;
friend class CollectAndReportRootsVisitor;
};
jvmtiError HeapUtil::FollowReferences(jvmtiEnv* env,
jint heap_filter,
jclass klass,
jobject initial_object,
const jvmtiHeapCallbacks* callbacks,
const void* user_data) {
if (callbacks == nullptr) {
return ERR(NULL_POINTER);
}
art::Thread* self = art::Thread::Current();
art::gc::Heap* heap = art::Runtime::Current()->GetHeap();
if (heap->IsGcConcurrentAndMoving()) {
// Need to take a heap dump while GC isn't running. See the
// comment in Heap::VisitObjects().
heap->IncrementDisableMovingGC(self);
}
{
art::ScopedObjectAccess soa(self); // Now we know we have the shared lock.
art::jni::ScopedEnableSuspendAllJniIdQueries sjni; // make sure we can get JNI ids.
art::ScopedThreadSuspension sts(self, art::ThreadState::kWaitingForVisitObjects);
art::ScopedSuspendAll ssa("FollowReferences");
art::ObjPtr<art::mirror::Class> class_filter = klass == nullptr
? nullptr
: art::ObjPtr<art::mirror::Class>::DownCast(self->DecodeJObject(klass));
FollowReferencesHelper frh(this,
env,
self->DecodeJObject(initial_object),
callbacks,
class_filter,
heap_filter,
user_data);
frh.Init();
frh.Work();
}
if (heap->IsGcConcurrentAndMoving()) {
heap->DecrementDisableMovingGC(self);
}
return ERR(NONE);
}
jvmtiError HeapUtil::GetLoadedClasses(jvmtiEnv* env,
jint* class_count_ptr,
jclass** classes_ptr) {
if (class_count_ptr == nullptr || classes_ptr == nullptr) {
return ERR(NULL_POINTER);
}
class ReportClassVisitor : public art::ClassVisitor {
public:
explicit ReportClassVisitor(art::Thread* self) : self_(self) {}
bool operator()(art::ObjPtr<art::mirror::Class> klass)
override REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (klass->IsLoaded() || klass->IsErroneous()) {
classes_.push_back(self_->GetJniEnv()->AddLocalReference<jclass>(klass));
}
return true;
}
art::Thread* self_;
std::vector<jclass> classes_;
};
art::Thread* self = art::Thread::Current();
ReportClassVisitor rcv(self);
{
art::ScopedObjectAccess soa(self);
art::Runtime::Current()->GetClassLinker()->VisitClasses(&rcv);
}
size_t size = rcv.classes_.size();
jclass* classes = nullptr;
jvmtiError alloc_ret = env->Allocate(static_cast<jlong>(size * sizeof(jclass)),
reinterpret_cast<unsigned char**>(&classes));
if (alloc_ret != ERR(NONE)) {
return alloc_ret;
}
for (size_t i = 0; i < size; ++i) {
classes[i] = rcv.classes_[i];
}
*classes_ptr = classes;
*class_count_ptr = static_cast<jint>(size);
return ERR(NONE);
}
jvmtiError HeapUtil::ForceGarbageCollection([[maybe_unused]] jvmtiEnv* env) {
art::Runtime::Current()->GetHeap()->CollectGarbage(/* clear_soft_references= */ false);
return ERR(NONE);
}
static constexpr jint kHeapIdDefault = 0;
static constexpr jint kHeapIdImage = 1;
static constexpr jint kHeapIdZygote = 2;
static constexpr jint kHeapIdApp = 3;
static jint GetHeapId(art::ObjPtr<art::mirror::Object> obj)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (obj == nullptr) {
return -1;
}
art::gc::Heap* const heap = art::Runtime::Current()->GetHeap();
const art::gc::space::ContinuousSpace* const space =
heap->FindContinuousSpaceFromObject(obj, true);
jint heap_type = kHeapIdApp;
if (space != nullptr) {
if (space->IsZygoteSpace()) {
heap_type = kHeapIdZygote;
} else if (space->IsImageSpace() && heap->ObjectIsInBootImageSpace(obj)) {
// Only count objects in the boot image as HPROF_HEAP_IMAGE, this leaves app image objects
// as HPROF_HEAP_APP. b/35762934
heap_type = kHeapIdImage;
}
} else {
const auto* los = heap->GetLargeObjectsSpace();
if (los->Contains(obj.Ptr()) && los->IsZygoteLargeObject(art::Thread::Current(), obj.Ptr())) {
heap_type = kHeapIdZygote;
}
}
return heap_type;
};
jvmtiError HeapExtensions::GetObjectHeapId(jvmtiEnv* env, jlong tag, jint* heap_id, ...) {
if (heap_id == nullptr) {
return ERR(NULL_POINTER);
}
art::Thread* self = art::Thread::Current();
auto work = [&]() REQUIRES_SHARED(art::Locks::mutator_lock_) {
ObjectTagTable* tag_table = ArtJvmTiEnv::AsArtJvmTiEnv(env)->object_tag_table.get();
art::ObjPtr<art::mirror::Object> obj = tag_table->Find(tag);
jint heap_type = GetHeapId(obj);
if (heap_type == -1) {
return ERR(NOT_FOUND);
}
*heap_id = heap_type;
return ERR(NONE);
};
if (!art::Locks::mutator_lock_->IsSharedHeld(self)) {
if (!self->IsThreadSuspensionAllowable()) {
return ERR(INTERNAL);
}
art::ScopedObjectAccess soa(self);
return work();
} else {
// We cannot use SOA in this case. We might be holding the lock, but may not be in the
// runnable state (e.g., during GC).
art::Locks::mutator_lock_->AssertSharedHeld(self);
// TODO: Investigate why ASSERT_SHARED_CAPABILITY doesn't work.
auto annotalysis_workaround = [&]() NO_THREAD_SAFETY_ANALYSIS {
return work();
};
return annotalysis_workaround();
}
}
static jvmtiError CopyStringAndReturn(jvmtiEnv* env, const char* in, char** out) {
jvmtiError error;
JvmtiUniquePtr<char[]> param_name = CopyString(env, in, &error);
if (param_name == nullptr) {
return error;
}
*out = param_name.release();
return ERR(NONE);
}
static constexpr const char* kHeapIdDefaultName = "default";
static constexpr const char* kHeapIdImageName = "image";
static constexpr const char* kHeapIdZygoteName = "zygote";
static constexpr const char* kHeapIdAppName = "app";
jvmtiError HeapExtensions::GetHeapName(jvmtiEnv* env, jint heap_id, char** heap_name, ...) {
switch (heap_id) {
case kHeapIdDefault:
return CopyStringAndReturn(env, kHeapIdDefaultName, heap_name);
case kHeapIdImage:
return CopyStringAndReturn(env, kHeapIdImageName, heap_name);
case kHeapIdZygote:
return CopyStringAndReturn(env, kHeapIdZygoteName, heap_name);
case kHeapIdApp:
return CopyStringAndReturn(env, kHeapIdAppName, heap_name);
default:
return ERR(ILLEGAL_ARGUMENT);
}
}
jvmtiError HeapExtensions::IterateThroughHeapExt(jvmtiEnv* env,
jint heap_filter,
jclass klass,
const jvmtiHeapCallbacks* callbacks,
const void* user_data) {
if (ArtJvmTiEnv::AsArtJvmTiEnv(env)->capabilities.can_tag_objects != 1) { \
return ERR(MUST_POSSESS_CAPABILITY); \
}
// ART extension API: Also pass the heap id.
auto ArtIterateHeap = [](art::mirror::Object* obj,
const jvmtiHeapCallbacks* cb_callbacks,
jlong class_tag,
jlong size,
jlong* tag,
jint length,
void* cb_user_data)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
jint heap_id = GetHeapId(obj);
using ArtExtensionAPI = jint (*)(jlong, jlong, jlong*, jint length, void*, jint);
return reinterpret_cast<ArtExtensionAPI>(cb_callbacks->heap_iteration_callback)(
class_tag, size, tag, length, cb_user_data, heap_id);
};
return DoIterateThroughHeap(ArtIterateHeap,
env,
ArtJvmTiEnv::AsArtJvmTiEnv(env)->object_tag_table.get(),
heap_filter,
klass,
callbacks,
user_data);
}
namespace {
using ObjectPtr = art::ObjPtr<art::mirror::Object>;
using ObjectMap = std::unordered_map<ObjectPtr, ObjectPtr, art::HashObjPtr>;
static void ReplaceObjectReferences(const ObjectMap& map)
REQUIRES(art::Locks::mutator_lock_,
art::Roles::uninterruptible_) {
art::Runtime::Current()->GetHeap()->VisitObjectsPaused(
[&](art::mirror::Object* ref) REQUIRES_SHARED(art::Locks::mutator_lock_) {
// Rewrite all references in the object if needed.
class ResizeReferenceVisitor {
public:
using CompressedObj = art::mirror::CompressedReference<art::mirror::Object>;
explicit ResizeReferenceVisitor(const ObjectMap& map, ObjectPtr ref)
: map_(map), ref_(ref) {}
// Ignore class roots.
void VisitRootIfNonNull(CompressedObj* root) const
REQUIRES_SHARED(art::Locks::mutator_lock_) {
if (root != nullptr) {
VisitRoot(root);
}
}
void VisitRoot(CompressedObj* root) const REQUIRES_SHARED(art::Locks::mutator_lock_) {
auto it = map_.find(root->AsMirrorPtr());
if (it != map_.end()) {
root->Assign(it->second);
art::WriteBarrier::ForEveryFieldWrite(ref_);
}
}
void operator()(art::ObjPtr<art::mirror::Object> obj,
art::MemberOffset off,
bool is_static) const
REQUIRES_SHARED(art::Locks::mutator_lock_) {
auto it = map_.find(obj->GetFieldObject<art::mirror::Object>(off));
if (it != map_.end()) {
UNUSED(is_static);
if (UNLIKELY(!is_static && off == art::mirror::Object::ClassOffset())) {
// We don't want to update the declaring class of any objects. They will be replaced
// in the heap and we need the declaring class to know its size.
return;
} else if (UNLIKELY(!is_static && off == art::mirror::Class::SuperClassOffset() &&
obj->IsClass())) {
// We don't want to be messing with the class hierarcy either.
return;
}
VLOG(plugin) << "Updating field at offset " << off.Uint32Value() << " of type "
<< obj->GetClass()->PrettyClass();
obj->SetFieldObject</*transaction*/ false>(off, it->second);
art::WriteBarrier::ForEveryFieldWrite(obj);
}
}
// java.lang.ref.Reference visitor.
void operator()([[maybe_unused]] art::ObjPtr<art::mirror::Class> klass,
art::ObjPtr<art::mirror::Reference> ref) const
REQUIRES_SHARED(art::Locks::mutator_lock_) {
operator()(ref, art::mirror::Reference::ReferentOffset(), /* is_static */ false);
}
private:
const ObjectMap& map_;
ObjectPtr ref_;
};
ResizeReferenceVisitor rrv(map, ref);
if (ref->IsClass()) {
// Class object native roots are the ArtField and ArtMethod 'declaring_class_' fields
// which we don't want to be messing with as it would break ref-visitor assumptions about
// what a class looks like. We want to keep the default behavior in other cases (such as
// dex-cache) though. Unfortunately there is no way to tell from the visitor where exactly
// the root came from.
// TODO It might be nice to have the visitors told where the reference came from.
ref->VisitReferences</*kVisitNativeRoots*/false>(rrv, rrv);
} else {
ref->VisitReferences</*kVisitNativeRoots*/true>(rrv, rrv);
}
});
}
static void ReplaceStrongRoots(art::Thread* self, const ObjectMap& map)
REQUIRES(art::Locks::mutator_lock_, art::Roles::uninterruptible_) {
// replace root references expcept java frames.
struct ResizeRootVisitor : public art::RootVisitor {
public:
explicit ResizeRootVisitor(const ObjectMap& map) : map_(map) {}
// TODO It's somewhat annoying to have to have this function implemented twice. It might be
// good/useful to implement operator= for CompressedReference to allow us to use a template to
// implement both of these.
void VisitRoots(art::mirror::Object*** roots, size_t count, const art::RootInfo& info) override
REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::mirror::Object*** end = roots + count;
for (art::mirror::Object** obj = *roots; roots != end; obj = *(++roots)) {
auto it = map_.find(*obj);
if (it != map_.end()) {
// Java frames might have the JIT doing optimizations (for example loop-unrolling or
// eliding bounds checks) so we need deopt them once we're done here.
if (info.GetType() == art::RootType::kRootJavaFrame) {
const art::JavaFrameRootInfo& jfri =
art::down_cast<const art::JavaFrameRootInfo&>(info);
if (jfri.GetVReg() == art::JavaFrameRootInfo::kMethodDeclaringClass) {
info.Describe(VLOG_STREAM(plugin) << "Not changing declaring-class during stack"
<< " walk. Found obsolete java frame id ");
continue;
} else {
info.Describe(VLOG_STREAM(plugin) << "Found java frame id ");
threads_with_roots_.insert(info.GetThreadId());
}
}
*obj = it->second.Ptr();
}
}
}
void VisitRoots(art::mirror::CompressedReference<art::mirror::Object>** roots,
size_t count,
const art::RootInfo& info) override REQUIRES_SHARED(art::Locks::mutator_lock_) {
art::mirror::CompressedReference<art::mirror::Object>** end = roots + count;
for (art::mirror::CompressedReference<art::mirror::Object>* obj = *roots; roots != end;
obj = *(++roots)) {
auto it = map_.find(obj->AsMirrorPtr());
if (it != map_.end()) {
// Java frames might have the JIT doing optimizations (for example loop-unrolling or
// eliding bounds checks) so we need deopt them once we're done here.
if (info.GetType() == art::RootType::kRootJavaFrame) {
const art::JavaFrameRootInfo& jfri =
art::down_cast<const art::JavaFrameRootInfo&>(info);
if (jfri.GetVReg() == art::JavaFrameRootInfo::kMethodDeclaringClass) {
info.Describe(VLOG_STREAM(plugin) << "Not changing declaring-class during stack"
<< " walk. Found obsolete java frame id ");
continue;
} else {
info.Describe(VLOG_STREAM(plugin) << "Found java frame id ");
threads_with_roots_.insert(info.GetThreadId());
}
}
obj->Assign(it->second);
}
}
}
const std::unordered_set<uint32_t>& GetThreadsWithJavaFrameRoots() const {
return threads_with_roots_;
}
private:
const ObjectMap& map_;
std::unordered_set<uint32_t> threads_with_roots_;
};
ResizeRootVisitor rrv(map);
art::Runtime::Current()->VisitRoots(&rrv, art::VisitRootFlags::kVisitRootFlagAllRoots);
// Handle java Frames. Annoyingly the JIT can embed information about the length of the array into
// the compiled code. By changing the length of the array we potentially invalidate these
// assumptions and so could cause (eg) OOB array access or other issues.
if (!rrv.GetThreadsWithJavaFrameRoots().empty()) {
art::MutexLock mu(self, *art::Locks::thread_list_lock_);
art::ThreadList* thread_list = art::Runtime::Current()->GetThreadList();
art::instrumentation::Instrumentation* instr = art::Runtime::Current()->GetInstrumentation();
for (uint32_t id : rrv.GetThreadsWithJavaFrameRoots()) {
art::Thread* t = thread_list->FindThreadByThreadId(id);
CHECK(t != nullptr) << "id " << id << " does not refer to a valid thread."
<< " Where did the roots come from?";
VLOG(plugin) << "Instrumenting thread stack of thread " << *t;
// TODO Use deopt manager. We need a version that doesn't acquire all the locks we
// already have.
// TODO We technically only need to do this if the frames are not already being interpreted.
// The cost for doing an extra stack walk is unlikely to be worth it though.
instr->InstrumentThreadStack(t, /* force_deopt= */ true);
}
}
}
static void ReplaceWeakRoots(art::Thread* self,
EventHandler* event_handler,
const ObjectMap& map)
REQUIRES(art::Locks::mutator_lock_, art::Roles::uninterruptible_) {
// Handle tags. We want to do this seprately from other weak-refs (handled below) because we need
// to send additional events and handle cases where the agent might have tagged the new
// replacement object during the VMObjectAlloc. We do this by removing all tags associated with
// both the obsolete and the new arrays. Then we send the ObsoleteObjectCreated event and cache
// the new tag values. We next update all the other weak-references (the tags have been removed)
// and finally update the tag table with the new values. Doing things in this way (1) keeps all
// code relating to updating weak-references together and (2) ensures we don't end up in strange
// situations where the order of weak-ref visiting affects the final tagging state. Since we have
// the mutator_lock_ and gc-paused throughout this whole process no threads should be able to see
// the interval where the objects are not tagged.
struct NewTagValue {
public:
ObjectPtr obsolete_obj_;
jlong obsolete_tag_;
ObjectPtr new_obj_;
jlong new_tag_;
};
// Map from the environment to the list of <obsolete_tag, new_tag> pairs that were changed.
std::unordered_map<ArtJvmTiEnv*, std::vector<NewTagValue>> changed_tags;
event_handler->ForEachEnv(self, [&](ArtJvmTiEnv* env) {
// Cannot have REQUIRES(art::Locks::mutator_lock_) since ForEachEnv doesn't require it.
art::Locks::mutator_lock_->AssertExclusiveHeld(self);
env->object_tag_table->Lock();
// Get the tags and clear them (so we don't need to special-case the normal weak-ref visitor)
for (auto it : map) {
jlong new_tag = 0;
jlong obsolete_tag = 0;
bool had_obsolete_tag = env->object_tag_table->RemoveLocked(it.first, &obsolete_tag);
bool had_new_tag = env->object_tag_table->RemoveLocked(it.second, &new_tag);
// Dispatch event.
if (had_obsolete_tag || had_new_tag) {
event_handler->DispatchEventOnEnv<ArtJvmtiEvent::kObsoleteObjectCreated>(
env, self, &obsolete_tag, &new_tag);
changed_tags.try_emplace(env).first->second.push_back(
{ it.first, obsolete_tag, it.second, new_tag });
}
}
// After weak-ref update we need to go back and re-add obsoletes. We wait to avoid having to
// deal with the visit-weaks overwriting the initial new_obj_ptr tag and generally making things
// difficult.
env->object_tag_table->Unlock();
});
// Handle weak-refs.
struct ReplaceWeaksVisitor : public art::IsMarkedVisitor {
public:
ReplaceWeaksVisitor(const ObjectMap& map) : map_(map) {}
art::mirror::Object* IsMarked(art::mirror::Object* obj)
REQUIRES_SHARED(art::Locks::mutator_lock_) {
auto it = map_.find(obj);
if (it != map_.end()) {
return it->second.Ptr();
} else {
return obj;
}
}
private:
const ObjectMap& map_;
};
ReplaceWeaksVisitor rwv(map);
art::Runtime* runtime = art::Runtime::Current();
runtime->SweepSystemWeaks(&rwv);
runtime->GetThreadList()->SweepInterpreterCaches(&rwv);
// Re-add the object tags. At this point all weak-references to the old_obj_ptr are gone.
event_handler->ForEachEnv(self, [&](ArtJvmTiEnv* env) {
// Cannot have REQUIRES(art::Locks::mutator_lock_) since ForEachEnv doesn't require it.
art::Locks::mutator_lock_->AssertExclusiveHeld(self);
env->object_tag_table->Lock();
auto it = changed_tags.find(env);
if (it != changed_tags.end()) {
for (const NewTagValue& v : it->second) {
env->object_tag_table->SetLocked(v.obsolete_obj_, v.obsolete_tag_);
env->object_tag_table->SetLocked(v.new_obj_, v.new_tag_);
}
}
env->object_tag_table->Unlock();
});
}
} // namespace
void HeapExtensions::ReplaceReference(art::Thread* self,
art::ObjPtr<art::mirror::Object> old_obj_ptr,
art::ObjPtr<art::mirror::Object> new_obj_ptr) {
ObjectMap map { { old_obj_ptr, new_obj_ptr } };
ReplaceReferences(self, map);
}
void HeapExtensions::ReplaceReferences(art::Thread* self, const ObjectMap& map) {
ReplaceObjectReferences(map);
ReplaceStrongRoots(self, map);
ReplaceWeakRoots(self, HeapExtensions::gEventHandler, map);
}
jvmtiError HeapExtensions::ChangeArraySize(jvmtiEnv* env, jobject arr, jsize new_size) {
if (ArtJvmTiEnv::AsArtJvmTiEnv(env)->capabilities.can_tag_objects != 1) {
return ERR(MUST_POSSESS_CAPABILITY);
}
art::Thread* self = art::Thread::Current();
ScopedNoUserCodeSuspension snucs(self);
art::ScopedObjectAccess soa(self);
if (arr == nullptr) {
JVMTI_LOG(INFO, env) << "Cannot resize a null object";
return ERR(NULL_POINTER);
}
art::ObjPtr<art::mirror::Class> klass(soa.Decode<art::mirror::Object>(arr)->GetClass());
if (!klass->IsArrayClass()) {
JVMTI_LOG(INFO, env) << klass->PrettyClass() << " is not an array class!";
return ERR(ILLEGAL_ARGUMENT);
}
if (new_size < 0) {
JVMTI_LOG(INFO, env) << "Cannot resize an array to a negative size";
return ERR(ILLEGAL_ARGUMENT);
}
// Allocate the new copy.
art::StackHandleScope<2> hs(self);
art::Handle<art::mirror::Array> old_arr(hs.NewHandle(soa.Decode<art::mirror::Array>(arr)));
art::MutableHandle<art::mirror::Array> new_arr(hs.NewHandle<art::mirror::Array>(nullptr));
if (klass->IsObjectArrayClass()) {
new_arr.Assign(
art::mirror::ObjectArray<art::mirror::Object>::Alloc(self, old_arr->GetClass(), new_size));
} else {
// NB This also copies the old array but since we aren't suspended we need to do this again to
// catch any concurrent modifications.
new_arr.Assign(art::mirror::Array::CopyOf(old_arr, self, new_size));
}
if (new_arr.IsNull()) {
self->AssertPendingOOMException();
JVMTI_LOG(INFO, env) << "Unable to allocate " << old_arr->GetClass()->PrettyClass()
<< " (length: " << new_size << ") due to OOME. Error was: "
<< self->GetException()->Dump();
self->ClearException();
return ERR(OUT_OF_MEMORY);
} else {
self->AssertNoPendingException();
}
// Suspend everything.
art::ScopedThreadSuspension sts(self, art::ThreadState::kSuspended);
art::gc::ScopedGCCriticalSection sgccs(
self, art::gc::GcCause::kGcCauseDebugger, art::gc::CollectorType::kCollectorTypeDebugger);
art::ScopedSuspendAll ssa("Resize array!");
// Replace internals.
new_arr->SetLockWord(old_arr->GetLockWord(false), false);
old_arr->SetLockWord(art::LockWord::Default(), false);
// Copy the contents now when everything is suspended.
int32_t size = std::min(old_arr->GetLength(), new_size);
switch (old_arr->GetClass()->GetComponentType()->GetPrimitiveType()) {
case art::Primitive::kPrimBoolean:
new_arr->AsBooleanArray()->Memcpy(0, old_arr->AsBooleanArray(), 0, size);
break;
case art::Primitive::kPrimByte:
new_arr->AsByteArray()->Memcpy(0, old_arr->AsByteArray(), 0, size);
break;
case art::Primitive::kPrimChar:
new_arr->AsCharArray()->Memcpy(0, old_arr->AsCharArray(), 0, size);
break;
case art::Primitive::kPrimShort:
new_arr->AsShortArray()->Memcpy(0, old_arr->AsShortArray(), 0, size);
break;
case art::Primitive::kPrimInt:
new_arr->AsIntArray()->Memcpy(0, old_arr->AsIntArray(), 0, size);
break;
case art::Primitive::kPrimLong:
new_arr->AsLongArray()->Memcpy(0, old_arr->AsLongArray(), 0, size);
break;
case art::Primitive::kPrimFloat:
new_arr->AsFloatArray()->Memcpy(0, old_arr->AsFloatArray(), 0, size);
break;
case art::Primitive::kPrimDouble:
new_arr->AsDoubleArray()->Memcpy(0, old_arr->AsDoubleArray(), 0, size);
break;
case art::Primitive::kPrimNot:
for (int32_t i = 0; i < size; i++) {
new_arr->AsObjectArray<art::mirror::Object>()->Set(
i, old_arr->AsObjectArray<art::mirror::Object>()->Get(i));
}
break;
case art::Primitive::kPrimVoid:
LOG(FATAL) << "void-array is not a legal type!";
UNREACHABLE();
}
// Actually replace all the pointers.
ReplaceReference(self, old_arr.Get(), new_arr.Get());
return OK;
}
void HeapExtensions::Register(EventHandler* eh) {
gEventHandler = eh;
}
} // namespace openjdkjvmti