[runtime] Introduce FastNewStrictArgumentsStub to optimize strict arguments.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index d440ae8c3b7b79bf29ea64039e7cc3f959be35e8..28ed7fb1230c4673ce9e4081808fbcb1a6b74b5b 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -262,27 +262,31 @@ void FullCodeGenerator::Generate() {
     // Arguments object must be allocated after the context object, in
     // case the "arguments" or ".arguments" variables are in the context.
     Comment cmnt(masm_, "[ Allocate arguments object");
-    DCHECK(rdi.is(ArgumentsAccessNewDescriptor::function()));
     if (!function_in_register) {
       __ movp(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
     }
-    // The receiver is just before the parameters on the caller's stack.
-    int num_parameters = info->scope()->num_parameters();
-    int offset = num_parameters * kPointerSize;
-    __ Move(ArgumentsAccessNewDescriptor::parameter_count(),
-            Smi::FromInt(num_parameters));
-    __ leap(ArgumentsAccessNewDescriptor::parameter_pointer(),
-            Operand(rbp, StandardFrameConstants::kCallerSPOffset + offset));
-
-    // Arguments to ArgumentsAccessStub:
-    //   function, parameter pointer, parameter count.
-    // The stub will rewrite parameter pointer and parameter count if the
-    // previous stack frame was an arguments adapter frame.
-    bool is_unmapped = is_strict(language_mode()) || !has_simple_parameters();
-    ArgumentsAccessStub::Type type = ArgumentsAccessStub::ComputeType(
-        is_unmapped, literal()->has_duplicate_parameters());
-    ArgumentsAccessStub stub(isolate(), type);
-    __ CallStub(&stub);
+    if (is_strict(language_mode()) || !has_simple_parameters()) {
+      FastNewStrictArgumentsStub stub(isolate());
+      __ CallStub(&stub);
+    } else {
+      DCHECK(rdi.is(ArgumentsAccessNewDescriptor::function()));
+      // The receiver is just before the parameters on the caller's stack.
+      int num_parameters = info->scope()->num_parameters();
+      int offset = num_parameters * kPointerSize;
+      __ Move(ArgumentsAccessNewDescriptor::parameter_count(),
+              Smi::FromInt(num_parameters));
+      __ leap(ArgumentsAccessNewDescriptor::parameter_pointer(),
+              Operand(rbp, StandardFrameConstants::kCallerSPOffset + offset));
+
+      // Arguments to ArgumentsAccessStub:
+      //   function, parameter pointer, parameter count.
+      // The stub will rewrite parameter pointer and parameter count if the
+      // previous stack frame was an arguments adapter frame.
+      ArgumentsAccessStub::Type type = ArgumentsAccessStub::ComputeType(
+          literal()->has_duplicate_parameters());
+      ArgumentsAccessStub stub(isolate(), type);
+      __ CallStub(&stub);
+    }
 
     SetVar(arguments, rax, rbx, rdx);
   }