Access double fields in C++ as uint64_t fields to preserve signaling bit of a NaN.

src/heap/heap.cc

 // Copyright 2012 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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/context-slot-cache.h"
 #include "src/base/bits.h"
@@ skipping 2397 matching lines @@
     set_empty_fixed_##type##_array(obj);                                \
   }
 
     TYPED_ARRAYS(ALLOCATE_EMPTY_FIXED_TYPED_ARRAY)
 #undef ALLOCATE_EMPTY_FIXED_TYPED_ARRAY
   }
   DCHECK(!InNewSpace(empty_fixed_array()));
   return true;
 }
 
-
-AllocationResult Heap::AllocateHeapNumber(double value, MutableMode mode,
+AllocationResult Heap::AllocateHeapNumber(MutableMode mode,
                                           PretenureFlag pretenure) {
   // Statically ensure that it is safe to allocate heap numbers in paged
   // spaces.
   int size = HeapNumber::kSize;
   STATIC_ASSERT(HeapNumber::kSize <= kMaxRegularHeapObjectSize);
 
   AllocationSpace space = SelectSpace(pretenure);
 
   HeapObject* result = nullptr;
   {
     AllocationResult allocation = AllocateRaw(size, space, kDoubleUnaligned);
     if (!allocation.To(&result)) return allocation;
   }
 
   Map* map = mode == MUTABLE ? mutable_heap_number_map() : heap_number_map();
   HeapObject::cast(result)->set_map_no_write_barrier(map);
-  HeapNumber::cast(result)->set_value(value);
   return result;
 }
 
 #define SIMD_ALLOCATE_DEFINITION(TYPE, Type, type, lane_count, lane_type) \
   AllocationResult Heap::Allocate##Type(lane_type lanes[lane_count],      \
                                         PretenureFlag pretenure) {        \
     int size = Type::kSize;                                               \
     STATIC_ASSERT(Type::kSize <= kMaxRegularHeapObjectSize);              \
                                                                           \
     AllocationSpace space = SelectSpace(pretenure);                       \
@@ skipping 146 matching lines @@
 void Heap::CreateInitialObjects() {
   HandleScope scope(isolate());
   Factory* factory = isolate()->factory();
 
   // The -0 value must be set before NewNumber works.
   set_minus_zero_value(*factory->NewHeapNumber(-0.0, IMMUTABLE, TENURED));
   DCHECK(std::signbit(minus_zero_value()->Number()) != 0);
 
   set_nan_value(*factory->NewHeapNumber(
       std::numeric_limits<double>::quiet_NaN(), IMMUTABLE, TENURED));
-  set_hole_nan_value(*factory->NewHeapNumber(bit_cast<double>(kHoleNanInt64),
-                                             IMMUTABLE, TENURED));
+  set_hole_nan_value(
+      *factory->NewHeapNumberFromBits(kHoleNanInt64, IMMUTABLE, TENURED));
   set_infinity_value(*factory->NewHeapNumber(V8_INFINITY, IMMUTABLE, TENURED));
   set_minus_infinity_value(
       *factory->NewHeapNumber(-V8_INFINITY, IMMUTABLE, TENURED));
 
   // Allocate initial string table.
   set_string_table(*StringTable::New(isolate(), kInitialStringTableSize));
 
   // Allocate
 
   // Finish initializing oddballs after creating the string table.
@@ skipping 3993 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8