[builtins] Migrate Math.log to TurboFan.

src/builtins.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/builtins.h"
 
 #include "src/api-arguments.h"
 #include "src/api-natives.h"
 #include "src/api.h"
 #include "src/base/once.h"
@@ skipping 2446 matching lines @@
   HandleScope scope(isolate);
   DCHECK_EQ(3, args.length());
   Handle<Object> x = args.at<Object>(1);
   Handle<Object> y = args.at<Object>(2);
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, x, Object::ToNumber(x));
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, y, Object::ToNumber(y));
   int product = static_cast<int>(NumberToUint32(*x) * NumberToUint32(*y));
   return *isolate->factory()->NewNumberFromInt(product);
 }
 
+// ES6 section 20.2.2.20 Math.log ( x )
+void Builtins::Generate_MathLog(CodeStubAssembler* assembler) {
+  using compiler::Node;
+
+  Node* x = assembler->Parameter(1);
+  Node* context = assembler->Parameter(4);
+  Node* x_value = assembler->TruncateTaggedToFloat64(context, x);
+  Node* value = assembler->Float64Log(x_value);
+  Node* result = assembler->ChangeFloat64ToTagged(value);
+  assembler->Return(result);
+}
+
 // ES6 section 20.2.2.28 Math.round ( x )
 void Builtins::Generate_MathRound(CodeStubAssembler* assembler) {
   Generate_MathRoundingOperation(assembler, &CodeStubAssembler::Float64Round);
 }
 
 // ES6 section 20.2.2.32 Math.sqrt ( x )
 void Builtins::Generate_MathSqrt(CodeStubAssembler* assembler) {
   using compiler::Node;
 
   Node* x = assembler->Parameter(1);
@@ skipping 3316 matching lines @@
 BUILTIN_LIST_T(DEFINE_BUILTIN_ACCESSOR_T)
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 #undef DEFINE_BUILTIN_ACCESSOR_T
 #undef DEFINE_BUILTIN_ACCESSOR_H
 
 }  // namespace internal
 }  // namespace v8