Make it possible to assert that certain instance types are compatible wrt HAllocate.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 4dd24fd871552456a10bb77ab8f6a0e4b4b25138..0e9cf42382754fb5a7f24e9d7bc4a72169fff96c 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -5428,6 +5428,49 @@ class HLoadGlobalGeneric V8_FINAL : public HTemplateInstruction<2> {
 
 class HAllocate V8_FINAL : public HTemplateInstruction<2> {
  public:
+  enum Flags {
+    ALLOCATE_IN_NEW_SPACE = 1 << 0,
+    ALLOCATE_IN_OLD_DATA_SPACE = 1 << 1,
+    ALLOCATE_IN_OLD_POINTER_SPACE = 1 << 2,
+    ALLOCATE_DOUBLE_ALIGNED = 1 << 3,
+    PREFILL_WITH_FILLER = 1 << 4,
+    CLEAR_NEXT_MAP_WORD = 1 << 5
+  };
+
+  static Flags ComputeFlags(PretenureFlag pretenure_flag,
+                            InstanceType instance_type) {
+    Flags flags = pretenure_flag == TENURED
+        ? (Heap::TargetSpaceId(instance_type) == OLD_POINTER_SPACE
+            ? ALLOCATE_IN_OLD_POINTER_SPACE : ALLOCATE_IN_OLD_DATA_SPACE)
+        : ALLOCATE_IN_NEW_SPACE;
+    if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
+      flags = static_cast<Flags>(flags | ALLOCATE_DOUBLE_ALIGNED);
+    }
+    // We have to fill the allocated object with one word fillers if we do
+    // not use allocation folding since some allocations may depend on each
+    // other, i.e., have a pointer to each other. A GC in between these
+    // allocations may leave such objects behind in a not completely initialized
+    // state.
+    if (!FLAG_use_gvn || !FLAG_use_allocation_folding) {
+      flags = static_cast<Flags>(flags | PREFILL_WITH_FILLER);
+    }
+    if (pretenure_flag == NOT_TENURED &&
+        AllocationSite::CanTrack(instance_type)) {
+      flags = static_cast<Flags>(flags | CLEAR_NEXT_MAP_WORD);
+    }
+    return flags;
+  }
+
+  static HAllocate* New(Zone* zone,
+                        HValue* context,
+                        HValue* size,
+                        HType type,
+                        Flags flags,
+                        Handle<AllocationSite> allocation_site =
+                            Handle<AllocationSite>::null()) {
+    return new(zone) HAllocate(context, size, type, flags, allocation_site);
+  }
+
   static HAllocate* New(Zone* zone,
                         HValue* context,
                         HValue* size,
@@ -5436,8 +5479,8 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
                         InstanceType instance_type,
                         Handle<AllocationSite> allocation_site =
                             Handle<AllocationSite>::null()) {
-    return new(zone) HAllocate(context, size, type, pretenure_flag,
-        instance_type, allocation_site);
+    Flags flags = ComputeFlags(pretenure_flag, instance_type);
+    return New(zone, context, size, type, flags, allocation_site);
   }
 
   // Maximum instance size for which allocations will be inlined.
@@ -5486,6 +5529,10 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
     flags_ = static_cast<HAllocate::Flags>(flags_ | PREFILL_WITH_FILLER);
   }
 
+  bool MustClearNextMapWord() const {
+    return (flags_ & CLEAR_NEXT_MAP_WORD) != 0;
+  }
+
   void MakeDoubleAligned() {
     flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
   }
@@ -5498,55 +5545,28 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
   DECLARE_CONCRETE_INSTRUCTION(Allocate)
 
  private:
-  enum Flags {
-    ALLOCATE_IN_NEW_SPACE = 1 << 0,
-    ALLOCATE_IN_OLD_DATA_SPACE = 1 << 1,
-    ALLOCATE_IN_OLD_POINTER_SPACE = 1 << 2,
-    ALLOCATE_DOUBLE_ALIGNED = 1 << 3,
-    PREFILL_WITH_FILLER = 1 << 4
-  };
-
   HAllocate(HValue* context,
             HValue* size,
             HType type,
-            PretenureFlag pretenure_flag,
-            InstanceType instance_type,
-            Handle<AllocationSite> allocation_site =
-                Handle<AllocationSite>::null())
+            Flags flags,
+            Handle<AllocationSite> allocation_site)
       : HTemplateInstruction<2>(type),
+        flags_(flags),
         dominating_allocate_(NULL),
-        filler_free_space_size_(NULL),
-        clear_next_map_word_(false) {
+        filler_free_space_size_(NULL) {
     SetOperandAt(0, context);
     SetOperandAt(1, size);
     set_representation(Representation::Tagged());
     SetFlag(kTrackSideEffectDominators);
     SetGVNFlag(kChangesNewSpacePromotion);
     SetGVNFlag(kDependsOnNewSpacePromotion);
-    flags_ = pretenure_flag == TENURED
-        ? (Heap::TargetSpaceId(instance_type) == OLD_POINTER_SPACE
-            ? ALLOCATE_IN_OLD_POINTER_SPACE : ALLOCATE_IN_OLD_DATA_SPACE)
-        : ALLOCATE_IN_NEW_SPACE;
-    if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
-      flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
-    }
-    // We have to fill the allocated object with one word fillers if we do
-    // not use allocation folding since some allocations may depend on each
-    // other, i.e., have a pointer to each other. A GC in between these
-    // allocations may leave such objects behind in a not completely initialized
-    // state.
-    if (!FLAG_use_gvn || !FLAG_use_allocation_folding) {
-      flags_ = static_cast<HAllocate::Flags>(flags_ | PREFILL_WITH_FILLER);
-    }
-    clear_next_map_word_ = pretenure_flag == NOT_TENURED &&
-        AllocationSite::CanTrack(instance_type);
 
     if (FLAG_trace_pretenuring) {
       PrintF("HAllocate with AllocationSite %p %s\n",
              allocation_site.is_null()
                  ? static_cast<void*>(NULL)
                  : static_cast<void*>(*allocation_site),
-             pretenure_flag == TENURED ? "tenured" : "not tenured");
+             IsNewSpaceAllocation() ? "not tenured" : "tenured");
     }
   }
 
@@ -5573,7 +5593,6 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
   Handle<Map> known_initial_map_;
   HAllocate* dominating_allocate_;
   HStoreNamedField* filler_free_space_size_;
-  bool clear_next_map_word_;
 };