/*
* Copyright (C) 2008 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 "reference_table.h"
#include "base/mutex.h"
#include "indirect_reference_table.h"
#include "mirror/array.h"
#include "mirror/array-inl.h"
#include "mirror/class.h"
#include "mirror/class-inl.h"
#include "mirror/object-inl.h"
#include "mirror/string-inl.h"
#include "thread.h"
#include "utils.h"
namespace art {
ReferenceTable::ReferenceTable(const char* name, size_t initial_size, size_t max_size)
: name_(name), max_size_(max_size) {
CHECK_LE(initial_size, max_size);
entries_.reserve(initial_size);
}
ReferenceTable::~ReferenceTable() {
}
void ReferenceTable::Add(mirror::Object* obj) {
DCHECK(obj != NULL);
VerifyObject(obj);
if (entries_.size() >= max_size_) {
LOG(FATAL) << "ReferenceTable '" << name_ << "' "
<< "overflowed (" << max_size_ << " entries)";
}
entries_.push_back(GcRoot<mirror::Object>(obj));
}
void ReferenceTable::Remove(mirror::Object* obj) {
// We iterate backwards on the assumption that references are LIFO.
for (int i = entries_.size() - 1; i >= 0; --i) {
mirror::Object* entry = entries_[i].Read();
if (entry == obj) {
entries_.erase(entries_.begin() + i);
return;
}
}
}
// If "obj" is an array, return the number of elements in the array.
// Otherwise, return zero.
static size_t GetElementCount(mirror::Object* obj) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (obj == NULL || obj == kClearedJniWeakGlobal || !obj->IsArrayInstance()) {
return 0;
}
return obj->AsArray()->GetLength();
}
struct ObjectComparator {
bool operator()(GcRoot<mirror::Object> root1, GcRoot<mirror::Object> root2)
// TODO: enable analysis when analysis can work with the STL.
NO_THREAD_SAFETY_ANALYSIS {
Locks::mutator_lock_->AssertSharedHeld(Thread::Current());
mirror::Object* obj1 = root1.Read<kWithoutReadBarrier>();
mirror::Object* obj2 = root2.Read<kWithoutReadBarrier>();
// Ensure null references and cleared jweaks appear at the end.
if (obj1 == NULL) {
return true;
} else if (obj2 == NULL) {
return false;
}
if (obj1 == kClearedJniWeakGlobal) {
return true;
} else if (obj2 == kClearedJniWeakGlobal) {
return false;
}
// Sort by class...
if (obj1->GetClass() != obj2->GetClass()) {
return obj1->GetClass()->IdentityHashCode() < obj2->IdentityHashCode();
} else {
// ...then by size...
size_t count1 = obj1->SizeOf();
size_t count2 = obj2->SizeOf();
if (count1 != count2) {
return count1 < count2;
} else {
// ...and finally by identity hash code.
return obj1->IdentityHashCode() < obj2->IdentityHashCode();
}
}
}
};
// Log an object with some additional info.
//
// Pass in the number of elements in the array (or 0 if this is not an
// array object), and the number of additional objects that are identical
// or equivalent to the original.
static void DumpSummaryLine(std::ostream& os, mirror::Object* obj, size_t element_count,
int identical, int equiv)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (obj == NULL) {
os << " NULL reference (count=" << equiv << ")\n";
return;
}
if (obj == kClearedJniWeakGlobal) {
os << " cleared jweak (count=" << equiv << ")\n";
return;
}
std::string className(PrettyTypeOf(obj));
if (obj->IsClass()) {
// We're summarizing multiple instances, so using the exemplar
// Class' type parameter here would be misleading.
className = "java.lang.Class";
}
if (element_count != 0) {
StringAppendF(&className, " (%zd elements)", element_count);
}
size_t total = identical + equiv + 1;
std::string msg(StringPrintf("%5zd of %s", total, className.c_str()));
if (identical + equiv != 0) {
StringAppendF(&msg, " (%d unique instances)", equiv + 1);
}
os << " " << msg << "\n";
}
size_t ReferenceTable::Size() const {
return entries_.size();
}
void ReferenceTable::Dump(std::ostream& os) {
os << name_ << " reference table dump:\n";
Dump(os, entries_);
}
void ReferenceTable::Dump(std::ostream& os, Table& entries) {
if (entries.empty()) {
os << " (empty)\n";
return;
}
// Dump the most recent N entries.
const size_t kLast = 10;
size_t count = entries.size();
int first = count - kLast;
if (first < 0) {
first = 0;
}
os << " Last " << (count - first) << " entries (of " << count << "):\n";
for (int idx = count - 1; idx >= first; --idx) {
mirror::Object* ref = entries[idx].Read();
if (ref == NULL) {
continue;
}
if (ref == kClearedJniWeakGlobal) {
os << StringPrintf(" %5d: cleared jweak\n", idx);
continue;
}
if (ref->GetClass() == NULL) {
// should only be possible right after a plain dvmMalloc().
size_t size = ref->SizeOf();
os << StringPrintf(" %5d: %p (raw) (%zd bytes)\n", idx, ref, size);
continue;
}
std::string className(PrettyTypeOf(ref));
std::string extras;
size_t element_count = GetElementCount(ref);
if (element_count != 0) {
StringAppendF(&extras, " (%zd elements)", element_count);
} else if (ref->GetClass()->IsStringClass()) {
mirror::String* s = const_cast<mirror::Object*>(ref)->AsString();
std::string utf8(s->ToModifiedUtf8());
if (s->GetLength() <= 16) {
StringAppendF(&extras, " \"%s\"", utf8.c_str());
} else {
StringAppendF(&extras, " \"%.16s... (%d chars)", utf8.c_str(), s->GetLength());
}
}
os << StringPrintf(" %5d: ", idx) << ref << " " << className << extras << "\n";
}
// Make a copy of the table and sort it.
Table sorted_entries;
for (size_t i = 0; i < entries.size(); ++i) {
mirror::Object* entry = entries[i].Read();
sorted_entries.push_back(GcRoot<mirror::Object>(entry));
}
std::sort(sorted_entries.begin(), sorted_entries.end(), ObjectComparator());
// Remove any uninteresting stuff from the list. The sort moved them all to the end.
while (!sorted_entries.empty() && sorted_entries.back().IsNull()) {
sorted_entries.pop_back();
}
while (!sorted_entries.empty() &&
sorted_entries.back().Read<kWithoutReadBarrier>() == kClearedJniWeakGlobal) {
sorted_entries.pop_back();
}
if (sorted_entries.empty()) {
return;
}
// Dump a summary of the whole table.
os << " Summary:\n";
size_t equiv = 0;
size_t identical = 0;
for (size_t idx = 1; idx < count; idx++) {
mirror::Object* prev = sorted_entries[idx-1].Read<kWithoutReadBarrier>();
mirror::Object* current = sorted_entries[idx].Read<kWithoutReadBarrier>();
size_t element_count = GetElementCount(prev);
if (current == prev) {
// Same reference, added more than once.
identical++;
} else if (current->GetClass() == prev->GetClass() && GetElementCount(current) == element_count) {
// Same class / element count, different object.
equiv++;
} else {
// Different class.
DumpSummaryLine(os, prev, element_count, identical, equiv);
equiv = identical = 0;
}
}
// Handle the last entry.
DumpSummaryLine(os, sorted_entries.back().Read<kWithoutReadBarrier>(),
GetElementCount(sorted_entries.back().Read<kWithoutReadBarrier>()),
identical, equiv);
}
void ReferenceTable::VisitRoots(RootCallback* visitor, void* arg, uint32_t tid,
RootType root_type) {
for (GcRoot<mirror::Object>& root : entries_) {
root.VisitRoot(visitor, arg, tid, root_type);
}
}
} // namespace art