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/*
* Copyright (C) 2014-2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "HeapVerifier.h"
#include "CodeBlock.h"
#include "HeapIterationScope.h"
#include "JSCInlines.h"
#include "JSObject.h"
#include "MarkedSpaceInlines.h"
#include "VMInspector.h"
#include "ValueProfile.h"
#include <wtf/ProcessID.h>
namespace JSC {
HeapVerifier::HeapVerifier(Heap* heap, unsigned numberOfGCCyclesToRecord)
: m_heap(heap)
, m_currentCycle(0)
, m_numberOfCycles(numberOfGCCyclesToRecord)
{
RELEASE_ASSERT(m_numberOfCycles > 0);
m_cycles = std::make_unique<GCCycle[]>(m_numberOfCycles);
}
const char* HeapVerifier::phaseName(HeapVerifier::Phase phase)
{
switch (phase) {
case Phase::BeforeGC:
return "BeforeGC";
case Phase::BeforeMarking:
return "BeforeMarking";
case Phase::AfterMarking:
return "AfterMarking";
case Phase::AfterGC:
return "AfterGC";
}
RELEASE_ASSERT_NOT_REACHED();
return nullptr; // Silencing a compiler warning.
}
void HeapVerifier::startGC()
{
Heap* heap = m_heap;
incrementCycle();
currentCycle().reset();
currentCycle().scope = *heap->collectionScope();
currentCycle().timestamp = MonotonicTime::now();
ASSERT(!m_didPrintLogs);
}
void HeapVerifier::endGC()
{
if (m_didPrintLogs) {
dataLog("END ");
printVerificationHeader();
dataLog("\n\n");
m_didPrintLogs = false;
}
}
void HeapVerifier::gatherLiveCells(HeapVerifier::Phase phase)
{
Heap* heap = m_heap;
CellList& list = *cellListForGathering(phase);
list.reset();
heap->m_objectSpace.forEachLiveCell([&list] (HeapCell* cell, HeapCell::Kind kind) {
list.add({ cell, kind, CellProfile::Live });
return IterationStatus::Continue;
});
}
CellList* HeapVerifier::cellListForGathering(HeapVerifier::Phase phase)
{
switch (phase) {
case Phase::BeforeMarking:
return ¤tCycle().before;
case Phase::AfterMarking:
return ¤tCycle().after;
case Phase::BeforeGC:
case Phase::AfterGC:
// We should not be gathering live cells during these phases.
break;
}
RELEASE_ASSERT_NOT_REACHED();
return nullptr; // Silencing a compiler warning.
}
static void trimDeadCellsFromList(CellList& knownLiveSet, CellList& list)
{
if (!list.size())
return;
for (auto& cellProfile : list.cells()) {
if (cellProfile.isDead())
continue; // Don't "resurrect" known dead cells.
if (!knownLiveSet.find(cellProfile.cell())) {
cellProfile.setIsDead();
continue;
}
cellProfile.setIsLive();
}
}
void HeapVerifier::trimDeadCells()
{
CellList& knownLiveSet = currentCycle().after;
trimDeadCellsFromList(knownLiveSet, currentCycle().before);
for (int i = -1; i > -m_numberOfCycles; i--) {
trimDeadCellsFromList(knownLiveSet, cycleForIndex(i).before);
trimDeadCellsFromList(knownLiveSet, cycleForIndex(i).after);
}
}
void HeapVerifier::printVerificationHeader()
{
RELEASE_ASSERT(m_heap->collectionScope());
CollectionScope scope = currentCycle().scope;
MonotonicTime gcCycleTimestamp = currentCycle().timestamp;
dataLog("Verifying heap in [p", getCurrentProcessID(), ", ", Thread::current(), "] vm ",
RawPointer(m_heap->vm()), " on ", scope, " GC @ ", gcCycleTimestamp, "\n");
}
bool HeapVerifier::verifyCellList(Phase phase, CellList& list)
{
VM& vm = *m_heap->vm();
auto& liveCells = list.cells();
bool listNamePrinted = false;
auto printHeaderIfNeeded = [&] () {
if (listNamePrinted)
return;
printVerificationHeader();
dataLog(" @ phase ", phaseName(phase), ": FAILED in cell list '", list.name(), "' (size ", liveCells.size(), ")\n");
listNamePrinted = true;
m_didPrintLogs = true;
};
bool success = true;
for (size_t i = 0; i < liveCells.size(); i++) {
CellProfile& profile = liveCells[i];
if (!profile.isLive())
continue;
if (!profile.isJSCell())
continue;
JSCell* cell = profile.jsCell();
success |= validateJSCell(&vm, cell, &profile, &list, printHeaderIfNeeded, " ");
}
return success;
}
bool HeapVerifier::validateCell(HeapCell* cell, VM* expectedVM)
{
auto printNothing = [] () { };
if (cell->isZapped()) {
dataLog(" cell ", RawPointer(cell), " is ZAPPED\n");
return false;
}
if (cell->cellKind() != HeapCell::JSCell)
return true; // Nothing more to validate.
JSCell* jsCell = static_cast<JSCell*>(cell);
return validateJSCell(expectedVM, jsCell, nullptr, nullptr, printNothing);
}
bool HeapVerifier::validateJSCell(VM* expectedVM, JSCell* cell, CellProfile* profile, CellList* list, std::function<void()> printHeaderIfNeeded, const char* prefix)
{
auto printHeaderAndCell = [cell, profile, printHeaderIfNeeded, prefix] () {
printHeaderIfNeeded();
dataLog(prefix, "cell ", RawPointer(cell));
if (profile)
dataLog(" [", profile->className(), "]");
};
// 1. Validate the cell.
if (cell->isZapped()) {
printHeaderAndCell();
dataLog(" is zapped\n");
return false;
}
StructureID structureID = cell->structureID();
if (!structureID) {
printHeaderAndCell();
dataLog(" has NULL structureID\n");
return false;
}
if (expectedVM) {
VM& vm = *expectedVM;
VM* cellVM = cell->vm();
if (cellVM != expectedVM) {
printHeaderAndCell();
dataLog(" is from a different VM: expected:", RawPointer(expectedVM), " actual:", RawPointer(cellVM), "\n");
return false;
}
// 2. Validate the cell's structure
Structure* structure = vm.getStructure(structureID);
if (!structure) {
printHeaderAndCell();
#if USE(JSVALUE64)
uint32_t structureIDAsUint32 = structureID;
#else
uint32_t structureIDAsUint32 = reinterpret_cast<uint32_t>(structureID);
#endif
dataLog(" with structureID ", structureIDAsUint32, " maps to a NULL Structure pointer\n");
return false;
}
if (structure->isZapped()) {
printHeaderAndCell();
dataLog(" has ZAPPED structure ", RawPointer(structure), "\n");
return false;
}
if (!structure->structureID()) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structureID is NULL\n");
return false;
}
VM* structureVM = structure->vm();
if (structureVM != expectedVM) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " from a different VM: expected:", RawPointer(expectedVM), " actual:", RawPointer(structureVM), "\n");
return false;
}
if (list) {
auto* structureProfile = list->find(structure);
if (!structureProfile) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " NOT found in the live cell list\n");
return false;
}
if (!structureProfile->isLive()) {
printHeaderAndCell();
dataLog(" has DEAD structure ", RawPointer(structure), "\n");
return false;
}
}
StructureID structureStructureID = structure->structureID();
if (!structureStructureID) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " with a NULL structureID\n");
return false;
}
// 3. Validate the cell's structure's structure.
Structure* structureStructure = vm.getStructure(structureID);
if (!structureStructure) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structure is NULL\n");
return false;
}
if (structureStructure->isZapped()) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structure ", RawPointer(structureStructure), " is ZAPPED\n");
return false;
}
if (!structureStructure->structureID()) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structure ", RawPointer(structureStructure), " has a NULL structureID\n");
return false;
}
VM* structureStructureVM = structureStructure->vm();
if (structureStructureVM != expectedVM) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structure ", RawPointer(structureStructure), " is from a different VM: expected:", RawPointer(expectedVM), " actual:", RawPointer(structureStructureVM), "\n");
return false;
}
if (list) {
auto* structureStructureProfile = list->find(structureStructure);
if (!structureStructureProfile) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structure ", RawPointer(structureStructure), " is NOT found in the live cell list\n");
return false;
}
if (!structureStructureProfile->isLive()) {
printHeaderAndCell();
dataLog(" has structure ", RawPointer(structure), " whose structure ", RawPointer(structureStructure), " is DEAD\n");
return false;
}
}
CodeBlock* codeBlock = jsDynamicCast<CodeBlock*>(vm, cell);
if (UNLIKELY(codeBlock)) {
bool success = true;
for (unsigned i = 0; i < codeBlock->totalNumberOfValueProfiles(); ++i) {
ValueProfile& valueProfile = codeBlock->getFromAllValueProfiles(i);
for (unsigned i = 0; i < ValueProfile::totalNumberOfBuckets; ++i) {
JSValue value = JSValue::decode(valueProfile.m_buckets[i]);
if (!value)
continue;
if (!value.isCell())
continue;
JSCell* valueCell = value.asCell();
if (valueCell->isZapped()) {
printHeaderIfNeeded();
dataLog(prefix, "CodeBlock ", RawPointer(codeBlock), " has ZAPPED ValueProfile cell ", RawPointer(valueCell), "\n");
success = false;
continue;
}
}
}
if (!success)
return false;
}
}
return true;
}
void HeapVerifier::verify(HeapVerifier::Phase phase)
{
if (phase == Phase::AfterGC) {
bool verified = verifyCellList(phase, currentCycle().after);
RELEASE_ASSERT(verified);
}
}
void HeapVerifier::reportCell(CellProfile& profile, int cycleIndex, HeapVerifier::GCCycle& cycle, CellList& list, const char* prefix)
{
HeapCell* cell = profile.cell();
VM* vm = m_heap->vm();
if (prefix)
dataLog(prefix);
dataLog("FOUND");
if (profile.isLive())
dataLog(" LIVE");
else if (profile.isDead())
dataLog(" DEAD");
if (!profile.isJSCell())
dataLog(" HeapCell ");
else
dataLog(" JSCell ");
dataLog(RawPointer(cell));
if (profile.className())
dataLog(" [", profile.className(), "]");
if (profile.isLive() && profile.isJSCell()) {
JSCell* jsCell = profile.jsCell();
Structure* structure = jsCell->structure();
dataLog(" structure:", RawPointer(structure));
if (jsCell->isObject()) {
JSObject* obj = static_cast<JSObject*>(cell);
Butterfly* butterfly = obj->butterfly();
void* butterflyBase = butterfly->base(structure);
dataLog(" butterfly:", RawPointer(butterfly), " (base:", RawPointer(butterflyBase), ")");
}
}
dataLog(" in ", cycle.scope, " GC[", cycleIndex, "] in '", list.name(), "' list in VM ",
RawPointer(vm), " recorded at time ", profile.timestamp(), "\n");
if (profile.stackTrace())
dataLog(*profile.stackTrace());
}
void HeapVerifier::checkIfRecorded(HeapCell* cell)
{
bool found = false;
const char* const prefix = " ";
static const bool verbose = true;
for (int cycleIndex = 0; cycleIndex > -m_numberOfCycles; cycleIndex--) {
GCCycle& cycle = cycleForIndex(cycleIndex);
CellList* lists[] = { &cycle.before, &cycle.after };
if (verbose)
dataLog("Checking ", cycle.scope, " GC<", cycle.timestamp, ">, cycle [", cycleIndex, "]:\n");
const char* resultPrefix = " ";
for (auto* list : lists) {
if (verbose)
dataLog(prefix, "Cycle [", cycleIndex, "] '", list->name(), "' list: ");
CellProfile* profile = list->find(cell);
if (profile) {
reportCell(*profile, cycleIndex, cycle, *list, resultPrefix);
found = true;
} else if (verbose)
dataLog(resultPrefix, "cell NOT found\n");
}
}
if (!found)
dataLog(prefix, "cell ", RawPointer(cell), " NOT FOUND\n");
}
// The following are slower but more robust versions of the corresponding functions of the same name.
// These robust versions are designed so that we can call them interactively from a C++ debugger
// to query if a candidate is recorded cell.
void HeapVerifier::checkIfRecorded(uintptr_t candidateCell)
{
HeapCell* candidateHeapCell = reinterpret_cast<HeapCell*>(candidateCell);
VMInspector& inspector = VMInspector::instance();
auto expectedLocker = inspector.lock(Seconds(2));
if (!expectedLocker) {
ASSERT(expectedLocker.error() == VMInspector::Error::TimedOut);
dataLog("ERROR: Timed out while waiting to iterate VMs.");
return;
}
auto& locker = expectedLocker.value();
inspector.iterate(locker, [&] (VM& vm) {
if (!vm.heap.m_verifier)
return VMInspector::FunctorStatus::Continue;
auto* verifier = vm.heap.m_verifier.get();
dataLog("Search for cell ", RawPointer(candidateHeapCell), " in VM ", RawPointer(&vm), ":\n");
verifier->checkIfRecorded(candidateHeapCell);
return VMInspector::FunctorStatus::Continue;
});
}
} // namespace JSC