Revert "Merge old data and pointer space."

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index a3436ed94d771602947fade2df9eacdca9237e82..245c7c040369af136046ab87e44c2ac748fe1c86 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -3729,12 +3729,8 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
     return false;
   }
 
-
-  if (!IsFoldable(dominator_allocate)) {
-    if (FLAG_trace_allocation_folding) {
-      PrintF("#%d (%s) cannot fold into #%d (%s), different spaces\n", id(),
-             Mnemonic(), dominator->id(), dominator->Mnemonic());
-    }
+  dominator_allocate = GetFoldableDominator(dominator_allocate);
+  if (dominator_allocate == NULL) {
     return false;
   }
 
@@ -3766,7 +3762,10 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
 
   DCHECK(
       (IsNewSpaceAllocation() && dominator_allocate->IsNewSpaceAllocation()) ||
-      (IsOldSpaceAllocation() && dominator_allocate->IsOldSpaceAllocation()));
+      (IsOldDataSpaceAllocation() &&
+       dominator_allocate->IsOldDataSpaceAllocation()) ||
+      (IsOldPointerSpaceAllocation() &&
+       dominator_allocate->IsOldPointerSpaceAllocation()));
 
   // First update the size of the dominator allocate instruction.
   dominator_size = dominator_allocate->size();
@@ -3857,6 +3856,70 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
 }
 
 
+HAllocate* HAllocate::GetFoldableDominator(HAllocate* dominator) {
+  if (!IsFoldable(dominator)) {
+    // We cannot hoist old space allocations over new space allocations.
+    if (IsNewSpaceAllocation() || dominator->IsNewSpaceAllocation()) {
+      if (FLAG_trace_allocation_folding) {
+        PrintF("#%d (%s) cannot fold into #%d (%s), new space hoisting\n", id(),
+               Mnemonic(), dominator->id(), dominator->Mnemonic());
+      }
+      return NULL;
+    }
+
+    HAllocate* dominator_dominator = dominator->dominating_allocate_;
+
+    // We can hoist old data space allocations over an old pointer space
+    // allocation and vice versa. For that we have to check the dominator
+    // of the dominator allocate instruction.
+    if (dominator_dominator == NULL) {
+      dominating_allocate_ = dominator;
+      if (FLAG_trace_allocation_folding) {
+        PrintF("#%d (%s) cannot fold into #%d (%s), different spaces\n", id(),
+               Mnemonic(), dominator->id(), dominator->Mnemonic());
+      }
+      return NULL;
+    }
+
+    // We can just fold old space allocations that are in the same basic block,
+    // since it is not guaranteed that we fill up the whole allocated old
+    // space memory.
+    // TODO(hpayer): Remove this limitation and add filler maps for each each
+    // allocation as soon as we have store elimination.
+    if (block()->block_id() != dominator_dominator->block()->block_id()) {
+      if (FLAG_trace_allocation_folding) {
+        PrintF("#%d (%s) cannot fold into #%d (%s), different basic blocks\n",
+               id(), Mnemonic(), dominator_dominator->id(),
+               dominator_dominator->Mnemonic());
+      }
+      return NULL;
+    }
+
+    DCHECK((IsOldDataSpaceAllocation() &&
+            dominator_dominator->IsOldDataSpaceAllocation()) ||
+           (IsOldPointerSpaceAllocation() &&
+            dominator_dominator->IsOldPointerSpaceAllocation()));
+
+    int32_t current_size = HConstant::cast(size())->GetInteger32Constant();
+    HStoreNamedField* dominator_free_space_size =
+        dominator->filler_free_space_size_;
+    if (dominator_free_space_size != NULL) {
+      // We already hoisted one old space allocation, i.e., we already installed
+      // a filler map. Hence, we just have to update the free space size.
+      dominator->UpdateFreeSpaceFiller(current_size);
+    } else {
+      // This is the first old space allocation that gets hoisted. We have to
+      // install a filler map since the follwing allocation may cause a GC.
+      dominator->CreateFreeSpaceFiller(current_size);
+    }
+
+    // We can hoist the old space allocation over the actual dominator.
+    return dominator_dominator;
+  }
+  return dominator;
+}
+
+
 void HAllocate::UpdateFreeSpaceFiller(int32_t free_space_size) {
   DCHECK(filler_free_space_size_ != NULL);
   Zone* zone = block()->zone();
@@ -3924,7 +3987,8 @@ void HAllocate::ClearNextMapWord(int offset) {
 std::ostream& HAllocate::PrintDataTo(std::ostream& os) const {  // NOLINT
   os << NameOf(size()) << " (";
   if (IsNewSpaceAllocation()) os << "N";
-  if (IsOldSpaceAllocation()) os << "P";
+  if (IsOldPointerSpaceAllocation()) os << "P";
+  if (IsOldDataSpaceAllocation()) os << "D";
   if (MustAllocateDoubleAligned()) os << "A";
   if (MustPrefillWithFiller()) os << "F";
   return os << ")";