[builtins] Introduce proper Float64Log2 and Float64Log10 operators.

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 75bdde6e2943d5c1dde0067f333c76e1fa50893b..3181477700b9ef53ecbe4b9f14466ae07265d2de 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -2503,6 +2503,30 @@ void Builtins::Generate_MathLog1p(CodeStubAssembler* assembler) {
   assembler->Return(result);
 }
 
+// ES6 section 20.2.2.23 Math.log2 ( x )
+void Builtins::Generate_MathLog2(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->Float64Log2(x_value);
+  Node* result = assembler->ChangeFloat64ToTagged(value);
+  assembler->Return(result);
+}
+
+// ES6 section 20.2.2.22 Math.log10 ( x )
+void Builtins::Generate_MathLog10(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->Float64Log10(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);