Add bignum fall-back when the fast dtoa doesn't succeed. This removes Gay's d...

src/dtoa.cc

 // Copyright 2010 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 12 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <math.h>
 
 #include "v8.h"
 #include "dtoa.h"
 
+#include "bignum-dtoa.h"
 #include "double.h"
 #include "fast-dtoa.h"
 #include "fixed-dtoa.h"
 
 namespace v8 {
 namespace internal {
 
-bool DoubleToAscii(double v, DtoaMode mode, int requested_digits,
+static BignumDtoaMode DtoaToBignumDtoaMode(DtoaMode dtoa_mode) {
+  switch (dtoa_mode) {
+    case DTOA_SHORTEST:  return BIGNUM_DTOA_SHORTEST;
+    case DTOA_FIXED:     return BIGNUM_DTOA_FIXED;
+    case DTOA_PRECISION: return BIGNUM_DTOA_PRECISION;
+    default:
+      UNREACHABLE();
+      return BIGNUM_DTOA_SHORTEST;  // To silence compiler.
+  }
+}
+
+
+void DoubleToAscii(double v, DtoaMode mode, int requested_digits,
                    Vector<char> buffer, int* sign, int* length, int* point) {
   ASSERT(!Double(v).IsSpecial());
   ASSERT(mode == DTOA_SHORTEST || requested_digits >= 0);
 
   if (Double(v).Sign() < 0) {
     *sign = 1;
     v = -v;
   } else {
     *sign = 0;
   }
 
   if (v == 0) {
     buffer[0] = '0';
     buffer[1] = '\0';
     *length = 1;
     *point = 1;
-    return true;
+    return;
   }
 
   if (mode == DTOA_PRECISION && requested_digits == 0) {
     buffer[0] = '\0';
     *length = 0;
-    return true;
+    return;
   }
 
+  bool fast_worked;
   switch (mode) {
     case DTOA_SHORTEST:
-      return FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, length, point);
+      fast_worked = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, length, point);
+      break;
     case DTOA_FIXED:
-      return FastFixedDtoa(v, requested_digits, buffer, length, point);
+      fast_worked = FastFixedDtoa(v, requested_digits, buffer, length, point);
+      break;
     case DTOA_PRECISION:
-      return FastDtoa(v, FAST_DTOA_PRECISION, requested_digits,
-                      buffer, length, point);
+      fast_worked = FastDtoa(v, FAST_DTOA_PRECISION, requested_digits,
+                             buffer, length, point);
+      break;
+    default:
+      UNREACHABLE();
+      fast_worked = false;
   }
-  return false;
+  if (fast_worked) return;
+
+  // If the fast dtoa didn't succeed use the slower bignum version.
+  BignumDtoaMode bignum_mode = DtoaToBignumDtoaMode(mode);
+  BignumDtoa(v, bignum_mode, requested_digits, buffer, length, point);
+  buffer[*length] = '\0';
 }
 
 } }  // namespace v8::internal