Lazily initialize fast_sqrt() and pass an Isolate parameter to it

src/x64/codegen-x64.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/x64/codegen-x64.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/codegen.h"
 #include "src/macro-assembler.h"
@@ skipping 46 matching lines @@
   CodeDesc desc;
   masm.GetCode(&desc);
   DCHECK(!RelocInfo::RequiresRelocation(desc));
 
   Assembler::FlushICache(isolate, buffer, actual_size);
   base::OS::ProtectCode(buffer, actual_size);
   return FUNCTION_CAST<UnaryMathFunctionWithIsolate>(buffer);
 }
 
 
-UnaryMathFunction CreateSqrtFunction() {
+UnaryMathFunctionWithIsolate CreateSqrtFunction(Isolate* isolate) {
   size_t actual_size;
   // Allocate buffer in executable space.
   byte* buffer =
       static_cast<byte*>(base::OS::Allocate(1 * KB, &actual_size, true));
-  if (buffer == NULL) return &std::sqrt;
+  if (buffer == nullptr) return nullptr;
 
-  MacroAssembler masm(NULL, buffer, static_cast<int>(actual_size),
+  MacroAssembler masm(isolate, buffer, static_cast<int>(actual_size),
                       CodeObjectRequired::kNo);
   // xmm0: raw double input.
   // Move double input into registers.
   __ Sqrtsd(xmm0, xmm0);
   __ Ret();
 
   CodeDesc desc;
   masm.GetCode(&desc);
   DCHECK(!RelocInfo::RequiresRelocation(desc));
 
-  Assembler::FlushICacheWithoutIsolate(buffer, actual_size);
+  Assembler::FlushICache(isolate, buffer, actual_size);
   base::OS::ProtectCode(buffer, actual_size);
-  return FUNCTION_CAST<UnaryMathFunction>(buffer);
+  return FUNCTION_CAST<UnaryMathFunctionWithIsolate>(buffer);
 }
 
 
 #ifdef _WIN64
 typedef double (*ModuloFunction)(double, double);
 // Define custom fmod implementation.
 ModuloFunction CreateModuloFunction() {
   size_t actual_size;
   byte* buffer = static_cast<byte*>(
       base::OS::Allocate(Assembler::kMinimalBufferSize, &actual_size, true));
@@ skipping 624 matching lines @@
     return Operand(base_reg_, argument_count_reg_, times_pointer_size,
         displacement_to_last_argument + (receiver - 1 - index) * kPointerSize);
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64