/*
* Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "gc/shenandoah/shenandoahAsserts.hpp"
#include "gc/shenandoah/shenandoahForwarding.inline.hpp"
#include "gc/shenandoah/shenandoahPhaseTimings.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahRootProcessor.hpp"
#include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
#include "gc/shenandoah/shenandoahUtils.hpp"
#include "gc/shenandoah/shenandoahVerifier.hpp"
#include "memory/allocation.hpp"
#include "memory/iterator.inline.hpp"
#include "memory/resourceArea.hpp"
#include "oops/compressedOops.inline.hpp"
#include "runtime/atomic.hpp"
#include "utilities/align.hpp"
// Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
#ifdef verify_oop
#undef verify_oop
#endif
class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
private:
const char* _phase;
ShenandoahVerifier::VerifyOptions _options;
ShenandoahVerifierStack* _stack;
ShenandoahHeap* _heap;
MarkBitMap* _map;
ShenandoahLivenessData* _ld;
void* _interior_loc;
oop _loc;
public:
ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
const char* phase, ShenandoahVerifier::VerifyOptions options) :
_phase(phase),
_options(options),
_stack(stack),
_heap(ShenandoahHeap::heap()),
_map(map),
_ld(ld),
_interior_loc(NULL),
_loc(NULL) { }
private:
void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
if (!test) {
ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
}
}
template <class T>
void do_oop_work(T* p) {
T o = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(o)) {
oop obj = CompressedOops::decode_not_null(o);
// Single threaded verification can use faster non-atomic stack and bitmap
// methods.
//
// For performance reasons, only fully verify non-marked field values.
// We are here when the host object for *p is already marked.
HeapWord* addr = (HeapWord*) obj;
if (_map->par_mark(addr)) {
verify_oop_at(p, obj);
_stack->push(ShenandoahVerifierTask(obj));
}
}
}
void verify_oop(oop obj) {
// Perform consistency checks with gradually decreasing safety level. This guarantees
// that failure report would not try to touch something that was not yet verified to be
// safe to process.
check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
"oop must be in heap");
check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
"oop must be aligned");
ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
Klass* obj_klass = obj->klass_or_null();
// Verify that obj is not in dead space:
{
// Do this before touching obj->size()
check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
"Object klass pointer should not be NULL");
check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
"Object klass pointer must go to metaspace");
HeapWord *obj_addr = (HeapWord *) obj;
check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
"Object start should be within the region");
if (!obj_reg->is_humongous()) {
check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
"Object end should be within the region");
} else {
size_t humongous_start = obj_reg->region_number();
size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
"Humongous object is in continuation that fits it");
}
}
// ------------ obj is safe at this point --------------
check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
"Object should be in active region");
switch (_options._verify_liveness) {
case ShenandoahVerifier::_verify_liveness_disable:
// skip
break;
case ShenandoahVerifier::_verify_liveness_complete:
Atomic::add(&_ld[obj_reg->region_number()], (uint) obj->size());
// fallthrough for fast failure for un-live regions:
case ShenandoahVerifier::_verify_liveness_conservative:
check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
"Object must belong to region with live data");
break;
default:
assert(false, "Unhandled liveness verification");
}
}
oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
ShenandoahHeapRegion* fwd_reg = NULL;
if (obj != fwd) {
check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
"Forwardee must be in heap");
check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
"Forwardee is set");
check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
"Forwardee must be aligned");
// Do this before touching fwd->size()
Klass* fwd_klass = fwd->klass_or_null();
check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
"Forwardee klass pointer should not be NULL");
check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
"Forwardee klass pointer must go to metaspace");
check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
"Forwardee klass pointer must go to metaspace");
fwd_reg = _heap->heap_region_containing(fwd);
// Verify that forwardee is not in the dead space:
check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
"Should have no humongous forwardees");
HeapWord *fwd_addr = (HeapWord *) fwd;
check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
"Forwardee start should be within the region");
check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
"Forwardee end should be within the region");
oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
"Double forwarding");
} else {
fwd_reg = obj_reg;
}
// ------------ obj and fwd are safe at this point --------------
switch (_options._verify_marked) {
case ShenandoahVerifier::_verify_marked_disable:
// skip
break;
case ShenandoahVerifier::_verify_marked_incomplete:
check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
"Must be marked in incomplete bitmap");
break;
case ShenandoahVerifier::_verify_marked_complete:
check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
"Must be marked in complete bitmap");
break;
default:
assert(false, "Unhandled mark verification");
}
switch (_options._verify_forwarded) {
case ShenandoahVerifier::_verify_forwarded_disable:
// skip
break;
case ShenandoahVerifier::_verify_forwarded_none: {
check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
"Should not be forwarded");
break;
}
case ShenandoahVerifier::_verify_forwarded_allow: {
if (obj != fwd) {
check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
"Forwardee should be in another region");
}
break;
}
default:
assert(false, "Unhandled forwarding verification");
}
switch (_options._verify_cset) {
case ShenandoahVerifier::_verify_cset_disable:
// skip
break;
case ShenandoahVerifier::_verify_cset_none:
check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
"Should not have references to collection set");
break;
case ShenandoahVerifier::_verify_cset_forwarded:
if (_heap->in_collection_set(obj)) {
check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
"Object in collection set, should have forwardee");
}
break;
default:
assert(false, "Unhandled cset verification");
}
}
public:
/**
* Verify object with known interior reference.
* @param p interior reference where the object is referenced from; can be off-heap
* @param obj verified object
*/
template <class T>
void verify_oop_at(T* p, oop obj) {
_interior_loc = p;
verify_oop(obj);
_interior_loc = NULL;
}
/**
* Verify object without known interior reference.
* Useful when picking up the object at known offset in heap,
* but without knowing what objects reference it.
* @param obj verified object
*/
void verify_oop_standalone(oop obj) {
_interior_loc = NULL;
verify_oop(obj);
_interior_loc = NULL;
}
/**
* Verify oop fields from this object.
* @param obj host object for verified fields
*/
void verify_oops_from(oop obj) {
_loc = obj;
obj->oop_iterate(this);
_loc = NULL;
}
virtual void do_oop(oop* p) { do_oop_work(p); }
virtual void do_oop(narrowOop* p) { do_oop_work(p); }
};
class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
private:
size_t _used, _committed, _garbage;
public:
ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
void heap_region_do(ShenandoahHeapRegion* r) {
_used += r->used();
_garbage += r->garbage();
_committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
}
size_t used() { return _used; }
size_t committed() { return _committed; }
size_t garbage() { return _garbage; }
};
class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
private:
ShenandoahHeap* _heap;
const char* _phase;
ShenandoahVerifier::VerifyRegions _regions;
public:
ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
_heap(ShenandoahHeap::heap()),
_phase(phase),
_regions(regions) {};
void print_failure(ShenandoahHeapRegion* r, const char* label) {
ResourceMark rm;
ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
stringStream ss;
r->print_on(&ss);
msg.append("%s", ss.as_string());
report_vm_error(__FILE__, __LINE__, msg.buffer());
}
void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
if (!test) {
print_failure(r, msg);
}
}
void heap_region_do(ShenandoahHeapRegion* r) {
switch (_regions) {
case ShenandoahVerifier::_verify_regions_disable:
break;
case ShenandoahVerifier::_verify_regions_notrash:
verify(r, !r->is_trash(),
"Should not have trash regions");
break;
case ShenandoahVerifier::_verify_regions_nocset:
verify(r, !r->is_cset(),
"Should not have cset regions");
break;
case ShenandoahVerifier::_verify_regions_notrash_nocset:
verify(r, !r->is_trash(),
"Should not have trash regions");
verify(r, !r->is_cset(),
"Should not have cset regions");
break;
default:
ShouldNotReachHere();
}
verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
"Capacity should match region size");
verify(r, r->bottom() <= r->top(),
"Region top should not be less than bottom");
verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
"Region TAMS should not be less than bottom");
verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
"Complete TAMS should not be larger than top");
verify(r, r->get_live_data_bytes() <= r->capacity(),
"Live data cannot be larger than capacity");
verify(r, r->garbage() <= r->capacity(),
"Garbage cannot be larger than capacity");
verify(r, r->used() <= r->capacity(),
"Used cannot be larger than capacity");
verify(r, r->get_shared_allocs() <= r->capacity(),
"Shared alloc count should not be larger than capacity");
verify(r, r->get_tlab_allocs() <= r->capacity(),
"TLAB alloc count should not be larger than capacity");
verify(r, r->get_gclab_allocs() <= r->capacity(),
"GCLAB alloc count should not be larger than capacity");
verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
"Accurate accounting: shared + TLAB + GCLAB = used");
verify(r, !r->is_empty() || !r->has_live(),
"Empty regions should not have live data");
verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
"Transitional: region flags and collection set agree");
verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
"Non-empty regions should have first seqnum set");
verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
"Non-empty regions should have first seqnum set to either GC or mutator");
verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
"Non-empty regions should have last seqnum set");
verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
"Non-empty regions should have last seqnum set to either GC or mutator");
verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
"First seqnum should not be greater than last timestamp");
verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
"First mutator seqnum should not be greater than last seqnum");
verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
"First GC seqnum should not be greater than last seqnum");
}
};
class ShenandoahVerifierReachableTask : public AbstractGangTask {
private:
const char* _label;
ShenandoahRootVerifier* _verifier;
ShenandoahVerifier::VerifyOptions _options;
ShenandoahHeap* _heap;
ShenandoahLivenessData* _ld;
MarkBitMap* _bitmap;
volatile size_t _processed;
public:
ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
ShenandoahLivenessData* ld,
ShenandoahRootVerifier* verifier,
const char* label,
ShenandoahVerifier::VerifyOptions options) :
AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
_label(label),
_verifier(verifier),
_options(options),
_heap(ShenandoahHeap::heap()),
_ld(ld),
_bitmap(bitmap),
_processed(0) {};
size_t processed() {
return _processed;
}
virtual void work(uint worker_id) {
ResourceMark rm;
ShenandoahVerifierStack stack;
// On level 2, we need to only check the roots once.
// On level 3, we want to check the roots, and seed the local stack.
// It is a lesser evil to accept multiple root scans at level 3, because
// extended parallelism would buy us out.
if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
|| (ShenandoahVerifyLevel >= 3)) {
ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
ShenandoahMessageBuffer("%s, Roots", _label),
_options);
if (_heap->unload_classes()) {
_verifier->strong_roots_do(&cl);
} else {
_verifier->roots_do(&cl);
}
}
size_t processed = 0;
if (ShenandoahVerifyLevel >= 3) {
ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
ShenandoahMessageBuffer("%s, Reachable", _label),
_options);
while (!stack.is_empty()) {
processed++;
ShenandoahVerifierTask task = stack.pop();
cl.verify_oops_from(task.obj());
}
}
Atomic::add(&_processed, processed);
}
};
class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
private:
const char* _label;
ShenandoahVerifier::VerifyOptions _options;
ShenandoahHeap *_heap;
MarkBitMap* _bitmap;
ShenandoahLivenessData* _ld;
volatile size_t _claimed;
volatile size_t _processed;
public:
ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
ShenandoahLivenessData* ld,
const char* label,
ShenandoahVerifier::VerifyOptions options) :
AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
_label(label),
_options(options),
_heap(ShenandoahHeap::heap()),
_bitmap(bitmap),
_ld(ld),
_claimed(0),
_processed(0) {};
size_t processed() {
return _processed;
}
virtual void work(uint worker_id) {
ShenandoahVerifierStack stack;
ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
ShenandoahMessageBuffer("%s, Marked", _label),
_options);
while (true) {
size_t v = Atomic::add(&_claimed, 1u) - 1;
if (v < _heap->num_regions()) {
ShenandoahHeapRegion* r = _heap->get_region(v);
if (!r->is_humongous() && !r->is_trash()) {
work_regular(r, stack, cl);
} else if (r->is_humongous_start()) {
work_humongous(r, stack, cl);
}
} else {
break;
}
}
}
virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
size_t processed = 0;
HeapWord* obj = r->bottom();
if (_heap->complete_marking_context()->is_marked((oop)obj)) {
verify_and_follow(obj, stack, cl, &processed);
}
Atomic::add(&_processed, processed);
}
virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
size_t processed = 0;
MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
// Bitmaps, before TAMS
if (tams > r->bottom()) {
HeapWord* start = r->bottom();
HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
while (addr < tams) {
verify_and_follow(addr, stack, cl, &processed);
addr += 1;
if (addr < tams) {
addr = mark_bit_map->get_next_marked_addr(addr, tams);
}
}
}
// Size-based, after TAMS
{
HeapWord* limit = r->top();
HeapWord* addr = tams;
while (addr < limit) {
verify_and_follow(addr, stack, cl, &processed);
addr += oop(addr)->size();
}
}
Atomic::add(&_processed, processed);
}
void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
if (!_bitmap->par_mark(addr)) return;
// Verify the object itself:
oop obj = oop(addr);
cl.verify_oop_standalone(obj);
// Verify everything reachable from that object too, hopefully realizing
// everything was already marked, and never touching further:
cl.verify_oops_from(obj);
(*processed)++;
while (!stack.is_empty()) {
ShenandoahVerifierTask task = stack.pop();
cl.verify_oops_from(task.obj());
(*processed)++;
}
}
};
class VerifyThreadGCState : public ThreadClosure {
private:
const char* _label;
char _expected;
public:
VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
void do_thread(Thread* t) {
char actual = ShenandoahThreadLocalData::gc_state(t);
if (actual != _expected) {
fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
}
}
};
class ShenandoahGCStateResetter : public StackObj {
private:
ShenandoahHeap* const _heap;
char _gc_state;
public:
ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) {
_gc_state = _heap->gc_state();
_heap->_gc_state.clear();
}
~ShenandoahGCStateResetter() {
_heap->_gc_state.set(_gc_state);
assert(_heap->gc_state() == _gc_state, "Should be restored");
}
};
void ShenandoahVerifier::verify_at_safepoint(const char *label,
VerifyForwarded forwarded, VerifyMarked marked,
VerifyCollectionSet cset,
VerifyLiveness liveness, VerifyRegions regions,
VerifyGCState gcstate) {
guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
// Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
// GC state checks
{
char expected = -1;
bool enabled;
switch (gcstate) {
case _verify_gcstate_disable:
enabled = false;
break;
case _verify_gcstate_forwarded:
enabled = true;
expected = ShenandoahHeap::HAS_FORWARDED;
break;
case _verify_gcstate_evacuation:
enabled = true;
expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
break;
case _verify_gcstate_stable:
enabled = true;
expected = ShenandoahHeap::STABLE;
break;
default:
enabled = false;
assert(false, "Unhandled gc-state verification");
}
if (enabled) {
char actual = _heap->gc_state();
if (actual != expected) {
fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
}
VerifyThreadGCState vtgcs(label, expected);
Threads::java_threads_do(&vtgcs);
}
}
// Deactivate barriers temporarily: Verifier wants plain heap accesses
ShenandoahGCStateResetter resetter;
// Heap size checks
{
ShenandoahHeapLocker lock(_heap->lock());
ShenandoahCalculateRegionStatsClosure cl;
_heap->heap_region_iterate(&cl);
size_t heap_used = _heap->used();
guarantee(cl.used() == heap_used,
"%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
label,
byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
size_t heap_committed = _heap->committed();
guarantee(cl.committed() == heap_committed,
"%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
label,
byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
}
// Internal heap region checks
if (ShenandoahVerifyLevel >= 1) {
ShenandoahVerifyHeapRegionClosure cl(label, regions);
_heap->heap_region_iterate(&cl);
}
OrderAccess::fence();
_heap->make_parsable(false);
// Allocate temporary bitmap for storing marking wavefront:
_verification_bit_map->clear();
// Allocate temporary array for storing liveness data
ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
// Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
// This verifies what application can see, since it only cares about reachable objects.
size_t count_reachable = 0;
if (ShenandoahVerifyLevel >= 2) {
ShenandoahRootVerifier verifier;
ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options);
_heap->workers()->run_task(&task);
count_reachable = task.processed();
}
// Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
// not the application, can see during the region scans. There is no reason to process the objects
// that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
// before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
// what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
// version
size_t count_marked = 0;
if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
_heap->workers()->run_task(&task);
count_marked = task.processed();
} else {
guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
}
// Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
// marked objects.
if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
for (size_t i = 0; i < _heap->num_regions(); i++) {
ShenandoahHeapRegion* r = _heap->get_region(i);
juint verf_live = 0;
if (r->is_humongous()) {
// For humongous objects, test if start region is marked live, and if so,
// all humongous regions in that chain have live data equal to their "used".
juint start_live = Atomic::load_acquire(&ld[r->humongous_start_region()->region_number()]);
if (start_live > 0) {
verf_live = (juint)(r->used() / HeapWordSize);
}
} else {
verf_live = Atomic::load_acquire(&ld[r->region_number()]);
}
size_t reg_live = r->get_live_data_words();
if (reg_live != verf_live) {
ResourceMark rm;
stringStream ss;
r->print_on(&ss);
fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
label, reg_live, verf_live, ss.as_string());
}
}
}
log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
label, ShenandoahVerifyLevel, count_reachable, count_marked);
FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
}
void ShenandoahVerifier::verify_generic(VerifyOption vo) {
verify_at_safepoint(
"Generic Verification",
_verify_forwarded_allow, // conservatively allow forwarded
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_disable, // cset may be inconsistent
_verify_liveness_disable, // no reliable liveness data
_verify_regions_disable, // no reliable region data
_verify_gcstate_disable // no data about gcstate
);
}
void ShenandoahVerifier::verify_before_concmark() {
if (_heap->has_forwarded_objects()) {
verify_at_safepoint(
"Before Mark",
_verify_forwarded_allow, // may have forwarded references
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_forwarded, // allow forwarded references to cset
_verify_liveness_disable, // no reliable liveness data
_verify_regions_notrash, // no trash regions
_verify_gcstate_forwarded // there are forwarded objects
);
} else {
verify_at_safepoint(
"Before Mark",
_verify_forwarded_none, // UR should have fixed up
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_none, // UR should have fixed this
_verify_liveness_disable, // no reliable liveness data
_verify_regions_notrash, // no trash regions
_verify_gcstate_stable // there are no forwarded objects
);
}
}
void ShenandoahVerifier::verify_after_concmark() {
verify_at_safepoint(
"After Mark",
_verify_forwarded_none, // no forwarded references
_verify_marked_complete, // bitmaps as precise as we can get
_verify_cset_none, // no references to cset anymore
_verify_liveness_complete, // liveness data must be complete here
_verify_regions_disable, // trash regions not yet recycled
_verify_gcstate_stable // mark should have stabilized the heap
);
}
void ShenandoahVerifier::verify_before_evacuation() {
verify_at_safepoint(
"Before Evacuation",
_verify_forwarded_none, // no forwarded references
_verify_marked_complete, // walk over marked objects too
_verify_cset_disable, // non-forwarded references to cset expected
_verify_liveness_complete, // liveness data must be complete here
_verify_regions_disable, // trash regions not yet recycled
_verify_gcstate_stable // mark should have stabilized the heap
);
}
void ShenandoahVerifier::verify_during_evacuation() {
verify_at_safepoint(
"During Evacuation",
_verify_forwarded_allow, // some forwarded references are allowed
_verify_marked_disable, // walk only roots
_verify_cset_disable, // some cset references are not forwarded yet
_verify_liveness_disable, // liveness data might be already stale after pre-evacs
_verify_regions_disable, // trash regions not yet recycled
_verify_gcstate_evacuation // evacuation is in progress
);
}
void ShenandoahVerifier::verify_after_evacuation() {
verify_at_safepoint(
"After Evacuation",
_verify_forwarded_allow, // objects are still forwarded
_verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
_verify_cset_forwarded, // all cset refs are fully forwarded
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash, // trash regions have been recycled already
_verify_gcstate_forwarded // evacuation produced some forwarded objects
);
}
void ShenandoahVerifier::verify_before_updaterefs() {
verify_at_safepoint(
"Before Updating References",
_verify_forwarded_allow, // forwarded references allowed
_verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
_verify_cset_forwarded, // all cset refs are fully forwarded
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash, // trash regions have been recycled already
_verify_gcstate_forwarded // evacuation should have produced some forwarded objects
);
}
void ShenandoahVerifier::verify_after_updaterefs() {
verify_at_safepoint(
"After Updating References",
_verify_forwarded_none, // no forwarded references
_verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
_verify_cset_none, // no cset references, all updated
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_nocset, // no cset regions, trash regions have appeared
_verify_gcstate_stable // update refs had cleaned up forwarded objects
);
}
void ShenandoahVerifier::verify_after_degenerated() {
verify_at_safepoint(
"After Degenerated GC",
_verify_forwarded_none, // all objects are non-forwarded
_verify_marked_complete, // all objects are marked in complete bitmap
_verify_cset_none, // no cset references
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash_nocset, // no trash, no cset
_verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
);
}
void ShenandoahVerifier::verify_before_traversal() {
verify_at_safepoint(
"Before Traversal",
_verify_forwarded_none, // cannot have forwarded objects
_verify_marked_disable, // bitmaps are not relevant before traversal
_verify_cset_none, // no cset references before traversal
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash_nocset, // no trash and no cset regions
_verify_gcstate_stable // nothing forwarded before traversal
);
}
void ShenandoahVerifier::verify_after_traversal() {
verify_at_safepoint(
"After Traversal",
_verify_forwarded_none, // cannot have forwarded objects
_verify_marked_complete, // should have complete marking after traversal
_verify_cset_none, // no cset references left after traversal
_verify_liveness_disable, // liveness data is not collected for new allocations
_verify_regions_nocset, // no cset regions, trash regions allowed
_verify_gcstate_stable // nothing forwarded after traversal
);
}
void ShenandoahVerifier::verify_before_fullgc() {
verify_at_safepoint(
"Before Full GC",
_verify_forwarded_allow, // can have forwarded objects
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_disable, // cset might be foobared
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_disable, // no reliable region data here
_verify_gcstate_disable // no reliable gcstate data
);
}
void ShenandoahVerifier::verify_after_fullgc() {
verify_at_safepoint(
"After Full GC",
_verify_forwarded_none, // all objects are non-forwarded
_verify_marked_complete, // all objects are marked in complete bitmap
_verify_cset_none, // no cset references
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash_nocset, // no trash, no cset
_verify_gcstate_stable // full gc cleaned up everything
);
}
class ShenandoahVerifyNoForwared : public OopClosure {
private:
template <class T>
void do_oop_work(T* p) {
T o = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(o)) {
oop obj = CompressedOops::decode_not_null(o);
oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
if (obj != fwd) {
ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
"Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
}
}
}
public:
void do_oop(narrowOop* p) { do_oop_work(p); }
void do_oop(oop* p) { do_oop_work(p); }
};
class ShenandoahVerifyInToSpaceClosure : public OopClosure {
private:
template <class T>
void do_oop_work(T* p) {
T o = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(o)) {
oop obj = CompressedOops::decode_not_null(o);
ShenandoahHeap* heap = ShenandoahHeap::heap_no_check();
if (!heap->marking_context()->is_marked(obj)) {
ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
"Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
}
if (heap->in_collection_set(obj)) {
ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
"Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
}
oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
if (obj != fwd) {
ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
"Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
}
}
}
public:
void do_oop(narrowOop* p) { do_oop_work(p); }
void do_oop(oop* p) { do_oop_work(p); }
};
void ShenandoahVerifier::verify_roots_in_to_space() {
ShenandoahRootVerifier verifier;
ShenandoahVerifyInToSpaceClosure cl;
verifier.oops_do(&cl);
}
void ShenandoahVerifier::verify_roots_no_forwarded() {
ShenandoahRootVerifier verifier;
ShenandoahVerifyNoForwared cl;
verifier.oops_do(&cl);
}
void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) {
ShenandoahRootVerifier verifier;
verifier.excludes(types);
ShenandoahVerifyNoForwared cl;
verifier.oops_do(&cl);
}