Parser: Delay internalizing strings and values.

src/ast-string-table.h

+// Copyright 2014 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
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+//       contributors may be used to endorse or promote products derived
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+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_AST_STRING_TABLE_H_

[rossberg, 2014/06/11 14:58:12]

How about renaming this module to AstValue, since strings are just one facet
now.

[marja, 2014/06/12 09:57:53]

Done (as discussed, renamed AstStringTable to AstValueFactory, and it takes care
of both AstStrings and AstValues).

+#define V8_AST_STRING_TABLE_H_
+
+#include "api.h"
+#include "hashmap.h"
+#include "utils.h"
+
+// AstString, AstValue and AstStringTable are for storing strings and values
+// independent of the V8 heap and internalizing them later. During parsing,
+// AstStrings and AstValues are created and stored outside the heap, in
+// AstStringTable. After parsing, the strings and values are internalized (moved
+// into the V8 heap).
+namespace v8 {
+namespace internal {
+
+class AstString {
+ public:
+  AstString(bool i, Vector<const byte> lb, int h)
+      : is_one_byte_(i),
+        literal_bytes_(lb),
+        hash_(h) {}
+
+  AstString()
+      : is_one_byte_(true),
+        hash_(0) {}
+
+  bool AsArrayIndex(uint32_t* index) const;
+
+  // The string is not NULL-terminated, use length() to find out the length.

[rossberg, 2014/06/11 14:58:12]

Nit: null-terminated, since it's not NULL the pointer.

[marja, 2014/06/12 09:57:53]

Done.

+  const unsigned char* raw_data() const { return literal_bytes_.start(); }
+  int length() const { return literal_bytes_.length(); }
+  bool is_one_byte() const { return is_one_byte_; }
+  bool IsOneByteEqualTo(const char* data) const;
+
+  // Puts the string into the V8 heap.
+  void Internalize(Isolate* isolate);
+
+  // This function can be called after internalizing.
+  V8_INLINE Handle<String> string() const {
+    ASSERT(!string_.is_null());
+    return string_;
+  }
+
+  // For storing AstStrings in a hash map.
+  int hash() const { return hash_; }
+  static bool Compare(void* a, void* b);
+
+ private:
+  friend class AstStringTable;
+
+  bool is_one_byte_;
+  // Weak. Points to memory owned by AstStringTable.
+  Vector<const byte> literal_bytes_;
+  int hash_;
+
+  // This is null until the string is internalized.
+  Handle<String> string_;
+};
+
+
+// AstValue is either a string, a number, a string array, a boolean, or a
+// special value (null, undefined, the hole).
+class AstValue : public ZoneObject {
+ public:
+  enum Type {

[rossberg, 2014/06/11 14:58:12]

Can we add the missing New* constructors below and make this enum private?

[marja, 2014/06/12 09:57:53]

Done.

+    STRING,
+    NUMBER,
+    SMI,
+    BOOLEAN,
+    STRING_ARRAY,
+    NULL_TYPE,
+    UNDEFINED,
+    THE_HOLE
+  };
+
+  bool IsString() const {
+    return type_ == STRING;
+  }
+
+  bool IsNumber() const {
+    return type_ == NUMBER || type_ == SMI;
+  }
+
+  const AstString* AsString() const {
+    if (type_ == STRING)
+      return string_;
+    UNREACHABLE();
+    return 0;
+  }
+
+  double AsNumber() const {
+    if (type_ == NUMBER)
+      return number_;
+    if (type_ == SMI)
+      return smi_;
+    UNREACHABLE();
+    return 0;
+  }
+
+  bool EqualsString(const AstString* string) const {
+    return type_ == STRING && string_ == string;
+  }
+
+  bool IsPropertyName() const;
+
+  bool BooleanValue() const;
+
+  void Internalize(Isolate* isolate);
+
+  // Can be called after Internalize has been called.
+  V8_INLINE Handle<Object> value() const {
+    if (type_ == STRING) {
+      return string_->string();
+    }
+    ASSERT(!value_.is_null());
+    return value_;
+  }
+
+ private:
+  friend class AstStringTable;
+
+  explicit AstValue(const AstString* s) :
+      type_(STRING) {
+    string_ = s;
+  }
+
+  explicit AstValue(double n) :
+      type_(NUMBER) {
+    number_ = n;
+  }
+
+  AstValue(Type t, int i) :
+      type_(t) {
+    ASSERT(type_ == SMI);
+    smi_ = i;
+  }
+
+  explicit AstValue(bool b) :
+      type_(BOOLEAN) {
+    bool_ = b;
+  }
+
+  explicit AstValue(ZoneList<const AstString*>* s) :
+      type_(STRING_ARRAY) {
+    strings_ = s;
+  }
+
+  explicit AstValue(Type t) :

[rossberg, 2014/06/11 14:58:12]

...and get rid of this one.

[marja, 2014/06/12 09:57:53]

No, I still need this one to be able to construct them. It'll be only used by
AstValueFactory::NewUndefined() etc., so not visible to outside (Parser or
such).

+      type_(t) {}
+
+  Type type_;
+
+  // Uninternalized value.
+  union {
+    const AstString* string_;
+    double number_;
+    int smi_;
+    bool bool_;
+    ZoneList<const AstString*>* strings_;
+  };
+
+  // Internalized value (empty before internalized).
+  Handle<Object> value_;
+};
+
+
+// For generating string constants.
+#define STRING_CONSTANTS(F) \
+  F(anonymous_function, "(anonymous function)") \
+  F(arguments, "arguments") \
+  F(done, "done") \
+  F(dot_for, ".for") \
+  F(dot_generator, ".generator") \
+  F(dot_generator_object, ".generator_object") \
+  F(dot_iterator, ".iterator") \
+  F(dot_module, ".module") \
+  F(dot_result, ".result") \
+  F(empty, "") \
+  F(eval, "eval") \
+  F(initialize_const_global, "initializeConstGlobal") \
+  F(initialize_var_global, "initializeVarGlobal") \
+  F(make_reference_error, "MakeReferenceError") \
+  F(make_syntax_error, "MakeSyntaxError") \
+  F(make_type_error, "MakeTypeError") \
+  F(module, "module") \
+  F(native, "native") \
+  F(next, "next") \
+  F(proto, "__proto__") \
+  F(prototype, "prototype") \
+  F(this, "this") \
+  F(use_strict, "use strict") \
+  F(value, "value")
+
+class AstStringTable {
+ public:
+  explicit AstStringTable(Zone* zone)
+      : literal_chars_(0),
+        string_table_keys_(0),
+        string_table_(AstString::Compare),
+        zone_(zone),
+        isolate_(NULL) {
+#define F(name, str) {      \
+      const char* data = str;          \
+      name##_string_ = GetOneByteString(                              \
+          Vector<const uint8_t>(reinterpret_cast<const uint8_t*>(data), \
+                                strlen(data)));                         \
+    }
+    STRING_CONSTANTS(F)
+#undef F
+  }
+
+  const AstString* GetOneByteString(Vector<const uint8_t> literal);
+  const AstString* GetTwoByteString(Vector<const uint16_t> literal);
+  const AstString* GetString(Handle<String> literal);
+
+  void Internalize(Isolate* isolate);
+
+#define F(name, str) \
+  const AstString* name##_string() const { return name##_string_; }
+  STRING_CONSTANTS(F)
+#undef F
+
+  const AstValue* NewValue(const AstString* string);

[rossberg, 2014/06/11 14:58:12]

It's weird that these functions are all members of AstStringTable. Rename this
to AstValueFactory or s.th like that?

Also, I'd prefer to name all these NewSomething consistently, for Something in
String, Number, Boolean, Undefined, etc. The Value suffix seems redundant once
these functions are in a proper place.

[marja, 2014/06/12 09:57:53]

Done.

+  const AstValue* NewNumberValue(double number);
+  const AstValue* NewSmiValue(int number);
+  const AstValue* NewValue(bool b);
+  const AstValue* NewValue(ZoneList<const AstString*>* strings);
+  const AstValue* NewValue(AstValue::Type t);
+
+ private:
+  const AstString* GetString(int hash, bool is_one_byte,
+                             Vector<const byte> literal_bytes);
+
+  // All strings are copied here, one after another (no NULLs inbetween).
+  Collector<byte> literal_chars_;
+  // List of all AstStrings we have created; keys of string_table_ are pointers
+  // into AstStrings in string_table_keys_.
+  Collector<AstString> string_table_keys_;
+  HashMap string_table_;
+  // For keeping track of all AstValues we've created (so that they can be
+  // internalized later).
+  List<AstValue*> values_;
+  Zone* zone_;
+  Isolate* isolate_;
+
+#define F(name, str) \
+  const AstString* name##_string_;
+  STRING_CONSTANTS(F)
+#undef F
+};
+
+} }  // namespace v8::internal
+
+#undef STRING_CONSTANTS
+
+#endif  // V8_AST_STRING_TABLE_H_