RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 18:37:35 +00:00
Code Issues Activity Actions

LibJS: Add a finalization pass to the garbage collector

Browse source 
Doing things in the destructor of a GC-allocated object isn't always
safe, in case it involves accessing other GC-allocated objects.
If they were already swept by GC, we'd be poking into freed memory.

This patch adds a separate finalization pass where GC calls finalize()
on every unmarked cell that's about to be deleted.

It's safe to access other GC objects in finalize(), even if they're
also unmarked.
This commit is contained in:
Andreas Kling 2022-10-20 18:35:19 +02:00
parent 6d830e6335
commit 07a36c8f80
3 changed files with 16 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

12
Userland/Libraries/LibJS/Heap/Heap.cpp
View file

@ -106,6 +106,7 @@ void Heap::collect_garbage(CollectionType collection_type, bool print_report)
gather_roots(roots);
mark_live_cells(roots);
}
finalize_unmarked_cells();
sweep_dead_cells(print_report, collection_measurement_timer);
}
@ -231,6 +232,17 @@ void Heap::mark_live_cells(HashTable<Cell*> const& roots)
m_uprooted_cells.clear();
}
void Heap::finalize_unmarked_cells()
{
for_each_block([&](auto& block) {
block.template for_each_cell_in_state<Cell::State::Live>([](Cell* cell) {
if (!cell->is_marked())
cell->finalize();
});
return IterationDecision::Continue;
});
}
void Heap::sweep_dead_cells(bool print_report, Core::ElapsedTimer const& measurement_timer)
{
dbgln_if(HEAP_DEBUG, "sweep_dead_cells:");