[heap] Let caller figure out target space for evacuation when compacting.

src/heap/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/mark-compact.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 3158 matching lines @@
   while (it.has_next()) {
     NewSpacePage* p = it.next();
     survivors_size += DiscoverAndEvacuateBlackObjectsOnPage(new_space, p);
   }
 
   heap_->IncrementYoungSurvivorsCounter(survivors_size);
   new_space->set_age_mark(new_space->top());
 }
 
 
-void MarkCompactCollector::EvacuateLiveObjectsFromPage(Page* p) {
+void MarkCompactCollector::EvacuateLiveObjectsFromPage(Page* p,
+                                                       PagedSpace* to_space) {
   AlwaysAllocateScope always_allocate(isolate());
-  PagedSpace* space = static_cast<PagedSpace*>(p->owner());
   DCHECK(p->IsEvacuationCandidate() && !p->WasSwept());
   p->SetWasSwept();
 
   int offsets[16];
 
   for (MarkBitCellIterator it(p); !it.Done(); it.Advance()) {
     Address cell_base = it.CurrentCellBase();
     MarkBit::CellType* cell = it.CurrentCell();
 
     if (*cell == 0) continue;
 
     int live_objects = MarkWordToObjectStarts(*cell, offsets);
     for (int i = 0; i < live_objects; i++) {
       Address object_addr = cell_base + offsets[i] * kPointerSize;
       HeapObject* object = HeapObject::FromAddress(object_addr);
       DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object)));
 
       int size = object->Size();
       AllocationAlignment alignment = object->RequiredAlignment();
       HeapObject* target_object = nullptr;
-      AllocationResult allocation = space->AllocateRaw(size, alignment);
+      AllocationResult allocation = to_space->AllocateRaw(size, alignment);
       if (!allocation.To(&target_object)) {
         // If allocation failed, use emergency memory and re-try allocation.
-        CHECK(space->HasEmergencyMemory());
-        space->UseEmergencyMemory();
-        allocation = space->AllocateRaw(size, alignment);
+        CHECK(to_space->HasEmergencyMemory());
+        to_space->UseEmergencyMemory();
+        allocation = to_space->AllocateRaw(size, alignment);
       }
       if (!allocation.To(&target_object)) {
         // OS refused to give us memory.
         V8::FatalProcessOutOfMemory("Evacuation");
         return;
       }
 
-      MigrateObject(target_object, object, size, space->identity());
+      MigrateObject(target_object, object, size, to_space->identity());
       DCHECK(object->map_word().IsForwardingAddress());
     }
 
     // Clear marking bits for current cell.
     *cell = 0;
   }
   p->ResetLiveBytes();
 }
 
 
@@ skipping 23 matching lines @@
     // Allocate emergency memory for the case when compaction fails due to out
     // of memory.
     if (!space->HasEmergencyMemory()) {
       space->CreateEmergencyMemory();  // If the OS lets us.
     }
     if (p->IsEvacuationCandidate()) {
       // During compaction we might have to request a new page in order to free
       // up a page.  Check that we actually got an emergency page above so we
       // can guarantee that this succeeds.
       if (space->HasEmergencyMemory()) {
-        EvacuateLiveObjectsFromPage(p);
+        EvacuateLiveObjectsFromPage(p, static_cast<PagedSpace*>(p->owner()));
         // Unlink the page from the list of pages here. We must not iterate
         // over that page later (e.g. when scan on scavenge pages are
         // processed). The page itself will be freed later and is still
         // reachable from the evacuation candidates list.
         p->Unlink();
       } else {
         // Without room for expansion evacuation is not guaranteed to succeed.
         // Pessimistically abandon unevacuated pages.
         for (int j = i; j < npages; j++) {
           Page* page = evacuation_candidates_[j];
@@ skipping 1401 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }  // namespace internal
 }  // namespace v8