Store RNG state on function context.

src/runtime/runtime-maths.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/assembler.h"
+#include "src/base/utils/random-number-generator.h"
 #include "src/codegen.h"
 #include "src/third_party/fdlibm/fdlibm.h"
 
 namespace v8 {
 namespace internal {
 
 #define RUNTIME_UNARY_MATH(Name, name)                       \
   RUNTIME_FUNCTION(Runtime_Math##Name) {                     \
     HandleScope scope(isolate);                              \
     DCHECK(args.length() == 1);                              \
@@ skipping 218 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_IsMinusZero) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(Object, obj, 0);
   if (!obj->IsHeapNumber()) return isolate->heap()->false_value();
   HeapNumber* number = HeapNumber::cast(obj);
   return isolate->heap()->ToBoolean(IsMinusZero(number->value()));
 }
+
+
+RUNTIME_FUNCTION(Runtime_InitializeRNG) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 0);
+  static const int kSize = 4;
+  Handle<FixedArray> array = isolate->factory()->NewFixedArray(kSize);
+  uint16_t seeds[kSize];
+  do {
+    isolate->random_number_generator()->NextBytes(seeds,
+                                                  kSize * sizeof(*seeds));
+  } while (!(seeds[0] && seeds[1] && seeds[2] && seeds[3]));
+  for (int i = 0; i < kSize; i++) array->set(i, Smi::FromInt(seeds[i]));
+  return *isolate->factory()->NewJSArrayWithElements(array);
+}
 }  // namespace internal
 }  // namespace v8