Lowered kMaxVirtualRegisters (fixes v8 2139 and chrome 123822 and 128252).

src/lithium.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 115 matching lines @@
   }
 
   LUnallocated(Policy policy, Lifetime lifetime) : LOperand(UNALLOCATED, 0) {
     Initialize(policy, 0, lifetime);
   }
 
   // The superclass has a KindField.  Some policies have a signed fixed
   // index in the upper bits.
   static const int kPolicyWidth = 3;
   static const int kLifetimeWidth = 1;
-  static const int kVirtualRegisterWidth = 18;
+  static const int kVirtualRegisterWidth = 15;
 
   static const int kPolicyShift = kKindFieldWidth;
   static const int kLifetimeShift = kPolicyShift + kPolicyWidth;
   static const int kVirtualRegisterShift = kLifetimeShift + kLifetimeWidth;
   static const int kFixedIndexShift =
       kVirtualRegisterShift + kVirtualRegisterWidth;
+  static const int kFixedIndexWidth = 32 - kFixedIndexShift;
+  STATIC_ASSERT(kFixedIndexWidth > 5);
 
   class PolicyField : public BitField<Policy, kPolicyShift, kPolicyWidth> { };
 
   class LifetimeField
       : public BitField<Lifetime, kLifetimeShift, kLifetimeWidth> {
   };
 
   class VirtualRegisterField
       : public BitField<unsigned,
                         kVirtualRegisterShift,
                         kVirtualRegisterWidth> {
   };
 
   static const int kMaxVirtualRegisters = 1 << kVirtualRegisterWidth;
-  static const int kMaxFixedIndex = 63;
-  static const int kMinFixedIndex = -64;
+  static const int kMaxFixedIndex = (1 << kFixedIndexWidth) - 1;
+  static const int kMinFixedIndex = -(1 << kFixedIndexWidth);
 
   bool HasAnyPolicy() const {
     return policy() == ANY;
   }
   bool HasFixedPolicy() const {
     return policy() == FIXED_REGISTER ||
         policy() == FIXED_DOUBLE_REGISTER ||
         policy() == FIXED_SLOT;
   }
   bool HasRegisterPolicy() const {
@@ skipping 532 matching lines @@
   ZoneList<Handle<JSFunction> > inlined_closures_;
 };
 
 
 int ElementsKindToShiftSize(ElementsKind elements_kind);
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_H_