Fix data view accessors to throw execptions on offsets bigger than size_t.

src/v8conversions.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 37 matching lines @@
 
 // Converts a string into a double value according to ECMA-262 9.3.1
 double StringToDouble(UnicodeCache* unicode_cache,
                       String* str,
                       int flags,
                       double empty_string_val = 0);
 
 // Converts a string into an integer.
 double StringToInt(UnicodeCache* unicode_cache, String* str, int radix);
 
+inline bool TryNumberToSize(Isolate* isolate,
+                            Object* number, size_t* result) {
+  SealHandleScope shs(isolate);
+  if (number->IsSmi()) {
+    int value = Smi::cast(number)->value();
+    ASSERT(
+        static_cast<unsigned>(Smi::kMaxValue)
+          <= std::numeric_limits<size_t>::max());
+    if (value >= 0) {
+      *result = static_cast<size_t>(value);
+      return true;
+    }
+    return false;
+  } else {
+    ASSERT(number->IsHeapNumber());
+    double value = HeapNumber::cast(number)->value();
+    if (value >= 0 &&
+        value <= std::numeric_limits<size_t>::max()) {
+      *result = static_cast<size_t>(value);
+      return true;
+    } else {
+      return false;
+    }
+  }
+}
+
 // Converts a number into size_t.
 inline size_t NumberToSize(Isolate* isolate,
                            Object* number) {
-  SealHandleScope shs(isolate);
-  if (number->IsSmi()) {
-    int value = Smi::cast(number)->value();
-    CHECK_GE(value, 0);
-    ASSERT(
-      static_cast<unsigned>(Smi::kMaxValue)
-        <= std::numeric_limits<size_t>::max());
-    return static_cast<size_t>(value);
-  } else {
-    ASSERT(number->IsHeapNumber());
-    double value = HeapNumber::cast(number)->value();
-    CHECK(value >= 0 &&
-          value <= std::numeric_limits<size_t>::max());
-    return static_cast<size_t>(value);
-  }
+  size_t result;
+  bool is_valid = TryNumberToSize(isolate, number, &result);
+  CHECK(is_valid);
+  return result;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8CONVERSIONS_H_