Make the strict-mode calling convention for contextual calls the default one.

src/x64/stub-cache-x64.cc

Index: src/x64/stub-cache-x64.cc
diff --git a/src/x64/stub-cache-x64.cc b/src/x64/stub-cache-x64.cc
index 49c46f9d3418130c6b91aa772b22d0668a471155..0d163017840fbff29e521b3524301123a1b592c9 100644
--- a/src/x64/stub-cache-x64.cc
+++ b/src/x64/stub-cache-x64.cc
@@ -2375,21 +2375,10 @@ void StubCompiler::GenerateBooleanCheck(Register object, Label* miss) {
 }
 
 
-void CallStubCompiler::PatchGlobalProxy(Handle<Object> object,
-                                        Handle<JSFunction> function) {
+void CallStubCompiler::PatchImplicitReceiver(Handle<Object> object) {
   if (object->IsGlobalObject()) {
     StackArgumentsAccessor args(rsp, arguments());
-    __ MoveHeapObject(rdx, handle(function->context()->global_proxy()));
-    __ movq(args.GetReceiverOperand(), rdx);
-  }
-}
-
-
-void CallStubCompiler::PatchGlobalProxy(Handle<Object> object,
-                                        Register function) {
-  if (object->IsGlobalObject()) {
-    FetchGlobalProxy(masm(), rdx, function);
-    StackArgumentsAccessor args(rsp, arguments().immediate());
+    __ LoadRoot(rdx, Heap::kUndefinedValueRootIndex);
     __ movq(args.GetReceiverOperand(), rdx);
   }
 }
@@ -2483,7 +2472,7 @@ void CallStubCompiler::GenerateJumpFunction(Handle<Object> object,
   GenerateFunctionCheck(function, rbx, miss);
 
   if (!function.is(rdi)) __ movq(rdi, function);
-  PatchGlobalProxy(object, function);
+  PatchImplicitReceiver(object);
 
   // Invoke the function.
   __ InvokeFunction(rdi, arguments(), JUMP_FUNCTION,
@@ -2596,15 +2585,6 @@ Handle<Code> StoreStubCompiler::CompileStoreCallback(
 #define __ ACCESS_MASM(masm)
 
 
-void CallStubCompiler::FetchGlobalProxy(MacroAssembler* masm,
-                                        Register target,
-                                        Register function) {
-  __ movq(target, FieldOperand(function, JSFunction::kContextOffset));
-  __ movq(target, ContextOperand(target, Context::GLOBAL_OBJECT_INDEX));
-  __ movq(target, FieldOperand(target, GlobalObject::kGlobalReceiverOffset));
-}
-
-
 void StoreStubCompiler::GenerateStoreViaSetter(
     MacroAssembler* masm,
     Handle<JSFunction> setter) {