Statically initialize ExternalReference constants

Make values which are referenced via ExternalReference constexpr, and
initialize them statically. This avoids dynamic initialization and
protects them against being overwritten from generated code.

R=neis@chromium.org

Bug: v8:7570
Change-Id: I1c6c10fbffea12dc1f5bf726313bf8388e6530a1
Reviewed-on: https://chromium-review.googlesource.com/1013518Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52633}

src/external-reference.cc

@@ -54,38 +54,35 @@ namespace internal {
 // -----------------------------------------------------------------------------
 // Common double constants.
 
-struct DoubleConstant BASE_EMBEDDED {
-  double min_int;
-  double one_half;
-  double minus_one_half;
-  double negative_infinity;
-  uint64_t the_hole_nan;
-  double uint32_bias;
-};
-
-static DoubleConstant double_constants;
-
-static struct V8_ALIGNED(16) {
+constexpr double double_min_int_constant = kMinInt;
+constexpr double double_one_half_constant = 0.5;
+constexpr double double_minus_one_half_constant = -0.5;
+constexpr double double_negative_infinity_constant = -V8_INFINITY;
+constexpr uint64_t double_the_hole_nan_constant = kHoleNanInt64;
+constexpr double double_uint32_bias_constant =
+    static_cast<double>(kMaxUInt32) + 1;
+
+constexpr struct V8_ALIGNED(16) {
   uint32_t a;
   uint32_t b;
   uint32_t c;
   uint32_t d;
 } float_absolute_constant = {0x7FFFFFFF, 0x7FFFFFFF, 0x7FFFFFFF, 0x7FFFFFFF};
 
-static struct V8_ALIGNED(16) {
+constexpr struct V8_ALIGNED(16) {
   uint32_t a;
   uint32_t b;
   uint32_t c;
   uint32_t d;
 } float_negate_constant = {0x80000000, 0x80000000, 0x80000000, 0x80000000};
 
-static struct V8_ALIGNED(16) {
+constexpr struct V8_ALIGNED(16) {
   uint64_t a;
   uint64_t b;
 } double_absolute_constant = {uint64_t{0x7FFFFFFFFFFFFFFF},
                               uint64_t{0x7FFFFFFFFFFFFFFF}};
 
-static struct V8_ALIGNED(16) {
+constexpr struct V8_ALIGNED(16) {
   uint64_t a;
   uint64_t b;
 } double_negate_constant = {uint64_t{0x8000000000000000},
@@ -103,16 +100,6 @@ static ExternalReference::Type BuiltinCallTypeForResultSize(int result_size) {
   UNREACHABLE();
 }
 
-void ExternalReference::SetUp() {
-  double_constants.min_int = kMinInt;
-  double_constants.one_half = 0.5;
-  double_constants.minus_one_half = -0.5;
-  double_constants.the_hole_nan = kHoleNanInt64;
-  double_constants.negative_infinity = -V8_INFINITY;
-  double_constants.uint32_bias =
-      static_cast<double>(static_cast<uint32_t>(0xFFFFFFFF)) + 1;
-}
-
 ExternalReference::ExternalReference(Address address, Isolate* isolate)
     : address_(Redirect(isolate, address)) {}
 
@@ -505,53 +492,55 @@ ExternalReference ExternalReference::address_of_pending_message_obj(
 }
 
 ExternalReference ExternalReference::address_of_min_int(Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<void*>(&double_constants.min_int));
+  return ExternalReference(reinterpret_cast<Address>(&double_min_int_constant));
 }
 
 ExternalReference ExternalReference::address_of_one_half(Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<void*>(&double_constants.one_half));
+  return ExternalReference(
+      reinterpret_cast<Address>(&double_one_half_constant));
 }
 
 ExternalReference ExternalReference::address_of_minus_one_half(
     Isolate* isolate) {
   return ExternalReference(
-      reinterpret_cast<void*>(&double_constants.minus_one_half));
+      reinterpret_cast<Address>(&double_minus_one_half_constant));
 }
 
 ExternalReference ExternalReference::address_of_negative_infinity(
     Isolate* isolate) {
   return ExternalReference(
-      reinterpret_cast<void*>(&double_constants.negative_infinity));
+      reinterpret_cast<Address>(&double_negative_infinity_constant));
 }
 
 ExternalReference ExternalReference::address_of_the_hole_nan(Isolate* isolate) {
   return ExternalReference(
-      reinterpret_cast<void*>(&double_constants.the_hole_nan));
+      reinterpret_cast<Address>(&double_the_hole_nan_constant));
 }
 
 ExternalReference ExternalReference::address_of_uint32_bias(Isolate* isolate) {
   return ExternalReference(
-      reinterpret_cast<void*>(&double_constants.uint32_bias));
+      reinterpret_cast<Address>(&double_uint32_bias_constant));
 }
 
 ExternalReference ExternalReference::address_of_float_abs_constant(
     Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<void*>(&float_absolute_constant));
+  return ExternalReference(reinterpret_cast<Address>(&float_absolute_constant));
 }
 
 ExternalReference ExternalReference::address_of_float_neg_constant(
     Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<void*>(&float_negate_constant));
+  return ExternalReference(reinterpret_cast<Address>(&float_negate_constant));
 }
 
 ExternalReference ExternalReference::address_of_double_abs_constant(
     Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<void*>(&double_absolute_constant));
+  return ExternalReference(
+      reinterpret_cast<Address>(&double_absolute_constant));
 }
 
 ExternalReference ExternalReference::address_of_double_neg_constant(
     Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<void*>(&double_negate_constant));
+  return ExternalReference(reinterpret_cast<Address>(&double_negate_constant));
 }
 
 ExternalReference ExternalReference::is_profiling_address(Isolate* isolate) {

src/external-reference.h

@@ -248,8 +248,6 @@ class ExternalReference BASE_EMBEDDED {
       EXTERNAL_REFERENCE_LIST(COUNT_EXTERNAL_REFERENCE);
 #undef COUNT_EXTERNAL_REFERENCE
 
-  static void SetUp();
-
   typedef Address ExternalReferenceRedirector(Address original, Type type);
 
   ExternalReference() : address_(kNullAddress) {}

src/v8.cc

@@ -81,7 +81,6 @@ void V8::InitializeOncePerProcessImpl() {
   sampler::Sampler::SetUp();
   CpuFeatures::Probe(false);
   ElementsAccessor::InitializeOncePerProcess();
-  ExternalReference::SetUp();
   Bootstrapper::InitializeOncePerProcess();
 }