Filter out recorded slots of deoptimized code objects directly after deoptimization.

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index 878efd639e192c04147f8c583e045c90999b4fa7..71290f192da172f1f9d948f60341c3cd56af67ed 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -293,8 +293,6 @@ void MarkCompactCollector::ClearInvalidSlotsBufferEntries(PagedSpace* space) {
 void MarkCompactCollector::ClearInvalidStoreAndSlotsBufferEntries() {
   heap_->store_buffer()->ClearInvalidStoreBufferEntries();
 
-  RemoveDeoptimizedCodeSlots();
-
   ClearInvalidSlotsBufferEntries(heap_->old_space());
   ClearInvalidSlotsBufferEntries(heap_->code_space());
   ClearInvalidSlotsBufferEntries(heap_->map_space());
@@ -769,7 +767,6 @@ void MarkCompactCollector::AbortCompaction() {
     }
     compacting_ = false;
     evacuation_candidates_.Rewind(0);
-    invalidated_code_.Rewind(0);
   }
   DCHECK_EQ(0, evacuation_candidates_.length());
 }
@@ -3593,7 +3590,11 @@ void MarkCompactCollector::InvalidateCode(Code* code) {
     MarkBit mark_bit = Marking::MarkBitFrom(code);
     if (Marking::IsWhite(mark_bit)) return;
 
-    invalidated_code_.Add(code);
+    // Ignore all slots that might have been recorded in the body of the
+    // deoptimized code object. Assumption: no slots will be recorded for
+    // this object after invalidating it.
+    RemoveObjectSlots(code->instruction_start(),
+                      code->address() + code->Size());
   }
 }
 
@@ -3604,42 +3605,6 @@ bool MarkCompactCollector::WillBeDeoptimized(Code* code) {
 }
 
 
-void MarkCompactCollector::RemoveDeoptimizedCodeSlots() {
-  int length = invalidated_code_.length();
-  for (int i = 0; i < length; i++) {
-    Code* code = invalidated_code_[i];
-    Page* p = Page::FromAddress(code->address());
-    if (!p->IsEvacuationCandidate() &&
-        !p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) {
-      // Ignore all slots that might have been recorded in the body of the
-      // deoptimized code object.
-      RemoveObjectSlots(code->instruction_start(),
-                        code->address() + code->Size());
-    }
-  }
-}
-
-
-void MarkCompactCollector::RemoveDeadInvalidatedCode() {
-  int length = invalidated_code_.length();
-  for (int i = 0; i < length; i++) {
-    if (!IsMarked(invalidated_code_[i])) invalidated_code_[i] = NULL;
-  }
-}
-
-
-void MarkCompactCollector::ProcessInvalidatedCode(ObjectVisitor* visitor) {
-  int length = invalidated_code_.length();
-  for (int i = 0; i < length; i++) {
-    Code* code = invalidated_code_[i];
-    if (code != NULL) {
-      code->Iterate(visitor);
-    }
-  }
-  invalidated_code_.Rewind(0);
-}
-
-
 void MarkCompactCollector::RemoveObjectSlots(Address start_slot,
                                              Address end_slot) {
   // Remove entries by replacing them with an old-space slot containing a smi
@@ -3647,9 +3612,8 @@ void MarkCompactCollector::RemoveObjectSlots(Address start_slot,
   int npages = evacuation_candidates_.length();
   for (int i = 0; i < npages; i++) {
     Page* p = evacuation_candidates_[i];
-    DCHECK(p->IsEvacuationCandidate() ||
-           p->IsFlagSet(Page::RESCAN_ON_EVACUATION));
-    if (p->IsEvacuationCandidate()) {
+    if (!p->IsEvacuationCandidate() &&

[Michael Starzinger, 2015/08/04 07:45:57]

As discussed offline: This change looks bogus, the body of the condition seem to
be unreachable now. This looks like it slipped in.

[Hannes Payer (out of office), 2015/08/10 12:04:55]

Done.

+        !p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) {
       SlotsBuffer::RemoveObjectSlots(heap_, p->slots_buffer(), start_slot,
                                      end_slot);
     }
@@ -3801,10 +3765,6 @@ void MarkCompactCollector::EvacuateNewSpaceAndCandidates() {
   EvacuationWeakObjectRetainer evacuation_object_retainer;
   heap()->ProcessAllWeakReferences(&evacuation_object_retainer);
 
-  // Visit invalidated code (we ignored all slots on it) and clear mark-bits
-  // under it.
-  ProcessInvalidatedCode(&updating_visitor);
-
   heap_->isolate()->inner_pointer_to_code_cache()->Flush();
 
   slots_buffer_allocator_.DeallocateChain(&migration_slots_buffer_);
@@ -4434,8 +4394,6 @@ void MarkCompactCollector::SweepSpaces() {
     }
   }
 
-  RemoveDeadInvalidatedCode();
-
   EvacuateNewSpaceAndCandidates();
 
   heap()->FreeDeadArrayBuffers(false);