Hydrogen array constructor cleanup and improvements

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 6b6ba79b44680eb3a2e5e1636053743845ff44a5..82bdf421148bd97fe9eaa57562fe6b2183faf7a9 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -1735,14 +1735,16 @@ class TransitionElementsKindStub : public HydrogenCodeStub {
 
 class ArrayConstructorStubBase : public HydrogenCodeStub {
  public:
-  ArrayConstructorStubBase(ElementsKind kind, bool disable_allocation_sites) {
+  ArrayConstructorStubBase(ElementsKind kind, bool ensure_context,
+                           bool disable_allocation_sites) {
     // It only makes sense to override local allocation site behavior
     // if there is a difference between the global allocation site policy
     // for an ElementsKind and the desired usage of the stub.
     ASSERT(!disable_allocation_sites ||
            AllocationSiteInfo::GetMode(kind) == TRACK_ALLOCATION_SITE);
     bit_field_ = ElementsKindBits::encode(kind) |
-        DisableAllocationSitesBits::encode(disable_allocation_sites);
+        DisableAllocationSitesBits::encode(disable_allocation_sites) |
+        EnsureContextBits::encode(ensure_context);
   }
 
   ElementsKind elements_kind() const {
@@ -1753,7 +1755,15 @@ class ArrayConstructorStubBase : public HydrogenCodeStub {
     return DisableAllocationSitesBits::decode(bit_field_);
   }
 
-  virtual bool IsPregenerated() { return true; }
+  bool ensure_context() const {
+    return EnsureContextBits::decode(bit_field_);
+  }
+
+  virtual bool IsPregenerated() {
+    // We only pre-generate stubs that verify correct context
+    return ensure_context();
+  }
+
   static void GenerateStubsAheadOfTime(Isolate* isolate);
   static void InstallDescriptors(Isolate* isolate);
 
@@ -1766,6 +1776,7 @@ class ArrayConstructorStubBase : public HydrogenCodeStub {
 
   class ElementsKindBits: public BitField<ElementsKind, 0, 8> {};
   class DisableAllocationSitesBits: public BitField<bool, 8, 1> {};
+  class EnsureContextBits: public BitField<bool, 9, 1> {};
   uint32_t bit_field_;
 
   DISALLOW_COPY_AND_ASSIGN(ArrayConstructorStubBase);
@@ -1776,8 +1787,10 @@ class ArrayNoArgumentConstructorStub : public ArrayConstructorStubBase {
  public:
   ArrayNoArgumentConstructorStub(
       ElementsKind kind,
+      bool ensure_context = true,
       bool disable_allocation_sites = false)
-      : ArrayConstructorStubBase(kind, disable_allocation_sites) {
+      : ArrayConstructorStubBase(kind, ensure_context,
+                                 disable_allocation_sites) {
   }
 
   virtual Handle<Code> GenerateCode();
@@ -1797,8 +1810,10 @@ class ArraySingleArgumentConstructorStub : public ArrayConstructorStubBase {
  public:
   ArraySingleArgumentConstructorStub(
       ElementsKind kind,
+      bool ensure_context = true,
       bool disable_allocation_sites = false)
-      : ArrayConstructorStubBase(kind, disable_allocation_sites) {
+      : ArrayConstructorStubBase(kind, ensure_context,
+                                 disable_allocation_sites) {
   }
 
   virtual Handle<Code> GenerateCode();
@@ -1818,8 +1833,10 @@ class ArrayNArgumentsConstructorStub : public ArrayConstructorStubBase {
  public:
   ArrayNArgumentsConstructorStub(
       ElementsKind kind,
+      bool ensure_context = true,
       bool disable_allocation_sites = false)
-      : ArrayConstructorStubBase(kind, disable_allocation_sites) {
+      : ArrayConstructorStubBase(kind, ensure_context,
+                                 disable_allocation_sites) {
   }
 
   virtual Handle<Code> GenerateCode();