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Clear StubCaches after shared GC

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StubCaches contain keys (internalized strings), which are stored in
shared space if the string table is shared.
After a GC, StubCaches are simply cleared to not contain pointers to
invalid objects (e.g a key was evacuated).
This CL clears the StubCaches also for shared GCs, as keys might not be
valid afterwards.

Clearing the caches is now done in GC directly instead of invoking
Callbacks. First, GC callbacks are not supported for shared GCs (and it
is preferred to not support them) and second, this way it is guaranteed
that the caches are cleared before any other callback might access the
stub caches.

Bug: v8:13537
Change-Id: I8c9782596e4a208b07a7273ebc59544f8095474f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4064259
Commit-Queue: Patrick Thier <pthier@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#84562}
This commit is contained in:
pthier 2022-11-29 16:55:29 +01:00 committed by V8 LUCI CQ
parent 140bebbba7
commit 723d14dce3
3 changed files with 20 additions and 23 deletions
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20
src/heap/heap.cc
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@ -2118,6 +2118,7 @@ void Heap::UpdateSurvivalStatistics(int start_new_space_size) {
}
namespace {
GCTracer::Scope::ScopeId CollectorScopeId(GarbageCollector collector) {
switch (collector) {
case GarbageCollector::MARK_COMPACTOR:
@ -2129,6 +2130,21 @@ GCTracer::Scope::ScopeId CollectorScopeId(GarbageCollector collector) {
}
UNREACHABLE();
}
void ClearStubCaches(Isolate* isolate) {
isolate->load_stub_cache()->Clear();
isolate->store_stub_cache()->Clear();
if (isolate->is_shared_heap_isolate()) {
isolate->global_safepoint()->IterateClientIsolates([](Isolate* client) {
if (client->is_shared_heap_isolate()) return;
client->load_stub_cache()->Clear();
client->store_stub_cache()->Clear();
});
}
}
} // namespace
size_t Heap::PerformGarbageCollection(GarbageCollector collector,
@ -2265,6 +2281,10 @@ size_t Heap::PerformGarbageCollection(GarbageCollector collector,
RecomputeLimits(collector);
if (collector == GarbageCollector::MARK_COMPACTOR) {
ClearStubCaches(isolate());
}
GarbageCollectionEpilogueInSafepoint(collector);
tracer()->StopInSafepoint();

19
src/ic/stub-cache.cc
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@ -14,29 +14,10 @@
namespace v8 {
namespace internal {
// static
void StubCache::ClearCallback(v8::Isolate* isolate, v8::GCType type,
v8::GCCallbackFlags flags, void* data) {
StubCache* cache = static_cast<StubCache*>(data);
cache->Clear();
}
StubCache::StubCache(Isolate* isolate) : isolate_(isolate) {
// Ensure the nullptr (aka Smi::zero()) which StubCache::Get() returns
// when the entry is not found is not considered as a handler.
DCHECK(!IC::IsHandler(MaybeObject()));
// The stub caches are not traversed during GC; clear them to force
// their lazy re-initialization. This must be done after the
// GC, because it relies on the new address of certain old space
// objects (empty string, illegal builtin).
isolate_->heap()->AddGCEpilogueCallback(ClearCallback,
kGCTypeMarkSweepCompact, this);
}
StubCache::~StubCache() {
isolate_->heap()->RemoveGCEpilogueCallback(ClearCallback, this);
}
void StubCache::Initialize() {

4
src/ic/stub-cache.h
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@ -98,12 +98,8 @@ class V8_EXPORT_PRIVATE StubCache {
static int PrimaryOffsetForTesting(Name name, Map map);
static int SecondaryOffsetForTesting(Name name, Map map);
static void ClearCallback(v8::Isolate* isolate, v8::GCType type,
v8::GCCallbackFlags flags, void* data);
// The constructor is made public only for the purposes of testing.
explicit StubCache(Isolate* isolate);
~StubCache();
StubCache(const StubCache&) = delete;
StubCache& operator=(const StubCache&) = delete;