Unify and fix checkers for duplicate object literal properties.

src/scanner.h

 // Copyright 2011 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 16 matching lines @@
 
 // Features shared by parsing and pre-parsing scanners.
 
 #ifndef V8_SCANNER_H_
 #define V8_SCANNER_H_
 
 #include "allocation.h"
 #include "char-predicates.h"
 #include "checks.h"
 #include "globals.h"
+#include "hashmap.h"
+#include "list.h"
 #include "token.h"
 #include "unicode-inl.h"
 #include "utils.h"
 
 namespace v8 {
 namespace internal {
 
 
 // Returns the value (0 .. 15) of a hexadecimal character c.
 // If c is not a legal hexadecimal character, returns a value < 0.
@@ skipping 67 matching lines @@
   // are more code_units available, return true.
   virtual bool ReadBlock() = 0;
   virtual unsigned SlowSeekForward(unsigned code_unit_count) = 0;
 
   const uc16* buffer_cursor_;
   const uc16* buffer_end_;
   unsigned pos_;
 };
 
 
-class UnicodeCache {
 // ---------------------------------------------------------------------
 // Caching predicates used by scanners.
+
+class UnicodeCache {
  public:
   UnicodeCache() {}
   typedef unibrow::Utf8Decoder<512> Utf8Decoder;
 
   StaticResource<Utf8Decoder>* utf8_decoder() {
     return &utf8_decoder_;
   }
 
   bool IsIdentifierStart(unibrow::uchar c) { return kIsIdentifierStart.get(c); }
   bool IsIdentifierPart(unibrow::uchar c) { return kIsIdentifierPart.get(c); }
   bool IsLineTerminator(unibrow::uchar c) { return kIsLineTerminator.get(c); }
   bool IsWhiteSpace(unibrow::uchar c) { return kIsWhiteSpace.get(c); }
 
  private:
   unibrow::Predicate<IdentifierStart, 128> kIsIdentifierStart;
   unibrow::Predicate<IdentifierPart, 128> kIsIdentifierPart;
   unibrow::Predicate<unibrow::LineTerminator, 128> kIsLineTerminator;
   unibrow::Predicate<unibrow::WhiteSpace, 128> kIsWhiteSpace;
   StaticResource<Utf8Decoder> utf8_decoder_;
 
   DISALLOW_COPY_AND_ASSIGN(UnicodeCache);
 };
 
 
+// ---------------------------------------------------------------------
+// DuplicateFinder discovers duplicate symbols.
+
+class DuplicateFinder {
+ public:
+  explicit DuplicateFinder(UnicodeCache* constants)
+      : unicode_constants_(constants),
+        backing_store_(16),
+        map_(&Match) { }
+
+  int AddAsciiSymbol(Vector<const char> key, int value);
+  int AddUtf16Symbol(Vector<const uint16_t> key, int value);
+  // Add a a number literal by converting it (if necessary)
+  // to the string that ToString(ToNumber(literal)) would generate.
+  // and then adding that string with AddAsciiSymbol.
+  // This string is the actual value used as key in an object literal,
+  // and the one that must be different from the other keys.
+  int AddNumber(Vector<const char> key, int value);
+
+ private:
+  int AddSymbol(Vector<const byte> key, bool is_ascii, int value);
+  // Backs up the key and its length in the backing store.
+  // The backup is stored with a base 127 encoding of the
+  // length (plus a bit saying whether the string is ASCII),
+  // followed by the bytes of the key.
+  byte* BackupKey(Vector<const byte> key, bool is_ascii);
+
+  // Compare two encoded keys (both pointing into the backing store)
+  // for having the same base-127 encoded lengths and ASCII-ness,
+  // and then having the same 'length' bytes following.
+  static bool Match(void* first, void* second);
+  // Creates a hash from a sequence of bytes.
+  static uint32_t Hash(Vector<const byte> key, bool is_ascii);
+  // Checks whether a string containing a JS number is its canonical
+  // form.
+  static bool IsNumberCanonical(Vector<const char> key);
+
+  // Size of buffer. Sufficient for using it to call DoubleToCString in
+  // from conversions.h.
+  static const int kBufferSize = 100;
+
+  UnicodeCache* unicode_constants_;
+  // Backing store used to store strings used as hashmap keys.
+  SequenceCollector<unsigned char> backing_store_;
+  HashMap map_;
+  // Buffer used for string->number->canonical string conversions.
+  char number_buffer_[kBufferSize];
+};
+
+
 // ----------------------------------------------------------------------------
 // LiteralBuffer -  Collector of chars of literals.
 
 class LiteralBuffer {
  public:
   LiteralBuffer() : is_ascii_(true), position_(0), backing_store_() { }
 
   ~LiteralBuffer() {
     if (backing_store_.length() > 0) {
       backing_store_.Dispose();
@@ skipping 401 matching lines @@
   bool harmony_scoping_;
   // Whether we scan 'module', 'import', 'export' as keywords.
   bool harmony_modules_;
   // Whether we scan 0o777 and 0b111 as numbers.
   bool harmony_numeric_literals_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCANNER_H_