Reintroduce duplicate identifier detection in preparser.

src/conversions-inl.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 14 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_CONVERSIONS_INL_H_
 #define V8_CONVERSIONS_INL_H_
 
 #include <limits.h>        // Required for INT_MAX etc.
 #include <math.h>
 #include <float.h>         // Required for DBL_MAX and on Win32 for finite()
 #include <stdarg.h>
+#include "globals.h"       // Required for V8_INFINITY
 
 // ----------------------------------------------------------------------------
 // Extra POSIX/ANSI functions for Win32/MSVC.
 
 #include "conversions.h"
 #include "strtod.h"
 #include "platform.h"
+#include "double.h"
 
 namespace v8 {
 namespace internal {
 
 static inline double JunkStringValue() {
   return std::numeric_limits<double>::quiet_NaN();
 }
 
 
 // The fast double-to-unsigned-int conversion routine does not guarantee
@@ skipping 28 matching lines @@
 static inline double DoubleToInteger(double x) {
   if (isnan(x)) return 0;
   if (!isfinite(x) || x == 0) return x;
   return (x >= 0) ? floor(x) : ceil(x);
 }
 
 
 int32_t DoubleToInt32(double x) {
   int32_t i = FastD2I(x);
   if (FastI2D(i) == x) return i;
-  static const double two32 = 4294967296.0;
-  static const double two31 = 2147483648.0;
-  if (!isfinite(x) || x == 0) return 0;
-  if (x < 0 || x >= two32) x = modulo(x, two32);
-  x = (x >= 0) ? floor(x) : ceil(x) + two32;
-  return (int32_t) ((x >= two31) ? x - two32 : x);
+  Double d(x);
+  int exponent = d.Exponent();
+  if (exponent < 0) {
+    if (exponent <= -Double::kSignificandSize) return 0;
+    return d.Sign() * static_cast<int32_t>(d.Significand() >> -exponent);
+  } else {
+    if (exponent > 31) return 0;
+    return d.Sign() * static_cast<int32_t>(d.Significand() << exponent);
+  }
 }
 
 
 template <class Iterator, class EndMark>
 static bool SubStringEquals(Iterator* current,
                             EndMark end,
                             const char* substring) {
   ASSERT(**current == *substring);
   for (substring++; *substring != '\0'; substring++) {
     ++*current;
@@ skipping 549 matching lines @@
   ASSERT(buffer_pos < kBufferSize);
   buffer[buffer_pos] = '\0';
 
   double converted = Strtod(Vector<const char>(buffer, buffer_pos), exponent);
   return negative ? -converted : converted;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONVERSIONS_INL_H_