1.1 --- a/src/TypeManager.cpp	Mon Dec 24 02:49:20 2012 -0800
     1.2 +++ b/src/TypeManager.cpp	Mon Dec 24 02:56:02 2012 -0800
     1.3 @@ -43,6 +43,10 @@
     1.4      if (!uncheckedType_)
     1.5          return false;
     1.6  
     1.7 +    stringType_ = Type::NewString(zone_);
     1.8 +    if (!stringType_)
     1.9 +        return false;
    1.10 +
    1.11      if ((primitiveTypes_[PrimitiveType_Int32] = Type::NewPrimitive(zone_, PrimitiveType_Int32)) == NULL)
    1.12          return false;
    1.13      if ((primitiveTypes_[PrimitiveType_Float] = Type::NewPrimitive(zone_, PrimitiveType_Float)) == NULL)
    1.14 @@ -53,8 +57,6 @@
    1.15          return false;
    1.16      if ((primitiveTypes_[PrimitiveType_Bool] = Type::NewPrimitive(zone_, PrimitiveType_Bool)) == NULL)
    1.17          return false;
    1.18 -    if ((primitiveTypes_[PrimitiveType_String] = Type::NewPrimitive(zone_, PrimitiveType_String)) == NULL)
    1.19 -        return false;
    1.20  
    1.21      Local<Type> type(zone_);
    1.22      for (unsigned i = 0; i < PrimitiveTypes_Total; i++) {
    1.23 @@ -100,6 +102,7 @@
    1.24  {
    1.25      visitor->visit(voidType_.address());
    1.26      visitor->visit(uncheckedType_.address());
    1.27 +    visitor->visit(stringType_.address());
    1.28      for (unsigned i = 0; i < PrimitiveTypes_Total; i++) {
    1.29          visitor->visit(primitiveTypes_[i].address());
    1.30          visitor->visit(referenceTypes_[i].address());

     2.1 --- a/src/TypeManager.h	Mon Dec 24 02:49:20 2012 -0800
     2.2 +++ b/src/TypeManager.h	Mon Dec 24 02:56:02 2012 -0800
     2.3 @@ -33,6 +33,7 @@
     2.4  
     2.5      // Primitive type cache.
     2.6      Unbarriered<Type> voidType_;
     2.7 +    Unbarriered<Type> stringType_;
     2.8      Unbarriered<Type> uncheckedType_;
     2.9      Unbarriered<Type> primitiveTypes_[PrimitiveTypes_Total];
    2.10      Unbarriered<ReferenceType> referenceTypes_[PrimitiveTypes_Total];
    2.11 @@ -46,6 +47,9 @@
    2.12          return primitiveTypes_[type];
    2.13      }
    2.14  
    2.15 +    Type *getString() {
    2.16 +        return stringType_;
    2.17 +    }
    2.18      Type *getVoid() {
    2.19          return voidType_;
    2.20      }

     3.1 --- a/src/Types.cpp	Mon Dec 24 02:49:20 2012 -0800
     3.2 +++ b/src/Types.cpp	Mon Dec 24 02:56:02 2012 -0800
     3.3 @@ -37,6 +37,17 @@
     3.4  }
     3.5  
     3.6  Type *
     3.7 +Type::NewString(Zone *zone)
     3.8 +{
     3.9 +    Local<Type> type(zone, Type::cast(zone->allocate(MapKind_Type, sizeof(Type), Heap::Tenure_Old)));
    3.10 +    if (!type)
    3.11 +        return NULL;
    3.12 +
    3.13 +    type->kind_ = STRING;
    3.14 +    return type;
    3.15 +}
    3.16 +
    3.17 +Type *
    3.18  Type::NewUnchecked(Zone *zone)
    3.19  {
    3.20      Local<Type> type(zone, Type::cast(zone->allocate(MapKind_Type, sizeof(Type), Heap::Tenure_Old)));

     4.1 --- a/src/Types.h	Mon Dec 24 02:49:20 2012 -0800
     4.2 +++ b/src/Types.h	Mon Dec 24 02:56:02 2012 -0800
     4.3 @@ -57,9 +57,6 @@
     4.4      // on 64-bit systems), and does not exist in language semantics.
     4.5      PrimitiveType_Native,
     4.6  
     4.7 -    // Internal string object.
     4.8 -    PrimitiveType_String,
     4.9 -
    4.10      PrimitiveTypes_Total
    4.11  };
    4.12  
    4.13 @@ -70,6 +67,25 @@
    4.14          // A primitive is a plain-old-data type.
    4.15          PRIMITIVE,
    4.16  
    4.17 +        // Void is an internal type used to specify that a function returns no
    4.18 +        // value.
    4.19 +        VOID,
    4.20 +
    4.21 +        // Enums are plain-old-data with int32 storage. They allow for extra
    4.22 +        // type checking that would not be possible with integers.
    4.23 +        ENUM,
    4.24 +
    4.25 +        // Unchecked is a magic type that has implicit, bitwise coercion to
    4.26 +        // int32, float, bool, or an enum.
    4.27 +        UNCHECKED,
    4.28 +
    4.29 +        // ------ Add traceable types below -------
    4.30 +
    4.31 +        // An immutable type that is a primitive in terms of language
    4.32 +        // semantics, but gets a special type here to make internal
    4.33 +        // logic easier.
    4.34 +        STRING,
    4.35 +
    4.36          // An array is a fixed-length vector of any other type.
    4.37          ARRAY,
    4.38          EXTERNAL_ARRAY,
    4.39 @@ -81,21 +97,9 @@
    4.40          // A function type encapsulates a function signature.
    4.41          FUNCTION,
    4.42  
    4.43 -        // Void is an internal type used to specify that a function returns no
    4.44 -        // value.
    4.45 -        VOID,
    4.46 -
    4.47 -        // Enums are plain-old-data with int32 storage. They allow for extra
    4.48 -        // type checking that would not be possible with integers.
    4.49 -        ENUM,
    4.50 -
    4.51          // Structs are composite records that may contain primitives, arrays,
    4.52          // functions, enums, and other structs.
    4.53 -        STRUCT,
    4.54 -
    4.55 -        // Unchecked is a magic type that has implicit, bitwise coercion to
    4.56 -        // int32, float, bool, or an enum.
    4.57 -        UNCHECKED
    4.58 +        STRUCT
    4.59      };
    4.60  
    4.61    private:
    4.62 @@ -107,6 +111,7 @@
    4.63      static Type *NewVoid(Zone *zone);
    4.64      static Type *NewUnchecked(Zone *zone);
    4.65      static Type *NewPrimitive(Zone *zone, PrimitiveType type);
    4.66 +    static Type *NewString(Zone *zone);
    4.67  
    4.68      static bool Compare(Type *left, Type *right);
    4.69  
    4.70 @@ -173,17 +178,13 @@
    4.71          return isPrimitive() && primitive() == PrimitiveType_Bool;
    4.72      }
    4.73      bool isString() {
    4.74 -        return isPrimitive() && primitive() == PrimitiveType_String;
    4.75 +        return kind() == STRING;
    4.76      }
    4.77      bool isExternalArray() {
    4.78          return kind() == EXTERNAL_ARRAY;
    4.79      }
    4.80      bool isTraceable() {
    4.81 -        return (isPrimitive() && primitive() == PrimitiveType_String) ||
    4.82 -               isReference() ||
    4.83 -               isArray() ||
    4.84 -               isStruct() ||
    4.85 -               isFunction();
    4.86 +        return kind_ >= STRING;
    4.87      }
    4.88      bool isConst() {
    4.89          assert(isPrimitive() ||

     5.1 --- a/src/compiler/SemanticAnalysis.cpp	Mon Dec 24 02:49:20 2012 -0800
     5.2 +++ b/src/compiler/SemanticAnalysis.cpp	Mon Dec 24 02:56:02 2012 -0800
     5.3 @@ -619,7 +619,7 @@
     5.4  void
     5.5  SemanticAnalysis::visitStringLiteral(StringLiteral *node)
     5.6  {
     5.7 -    Type *type = zone_->types()->getPrimitive(PrimitiveType_String);
     5.8 +    Type *type = zone_->types()->getString();
     5.9      hir_ = new (pool_) HString(node, type, node->string());
    5.10  }
    5.11