Sometimes avoid checking whether the receiver is an object in generated code.

src/x64/full-codegen-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2038 matching lines @@
       ISOLATE->stub_cache()->ComputeKeyedCallInitialize(arg_count, in_loop);
   __ movq(rcx, Operand(rsp, (arg_count + 1) * kPointerSize));  // Key.
   EmitCallIC(ic, mode, expr->id());
   RecordJSReturnSite(expr);
   // Restore context register.
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, rax);  // Drop the key still on the stack.
 }
 
 
-void FullCodeGenerator::EmitCallWithStub(Call* expr) {
+void FullCodeGenerator::EmitCallWithStub(Call* expr, CallFunctionFlags flags) {
   // Code common for calls using the call stub.
   ZoneList<Expression*>* args = expr->arguments();
   int arg_count = args->length();
   { PreservePositionScope scope(masm()->positions_recorder());
     for (int i = 0; i < arg_count; i++) {
       VisitForStackValue(args->at(i));
     }
   }
   // Record source position for debugger.
   SetSourcePosition(expr->position());
   InLoopFlag in_loop = (loop_depth() > 0) ? IN_LOOP : NOT_IN_LOOP;
-  CallFunctionStub stub(arg_count, in_loop, RECEIVER_MIGHT_BE_VALUE);
+  CallFunctionStub stub(arg_count, in_loop, flags);
   __ CallStub(&stub);
   RecordJSReturnSite(expr);
   // Restore context register.
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   // Discard the function left on TOS.
   context()->DropAndPlug(1, rax);
 }
 
 
 void FullCodeGenerator::EmitResolvePossiblyDirectEval(ResolveEvalFlag flag,
@@ skipping 114 matching lines @@
     // If fast case code has been generated, emit code to push the
     // function and receiver and have the slow path jump around this
     // code.
     if (done.is_linked()) {
       NearLabel call;
       __ jmp(&call);
       __ bind(&done);
       // Push function.
       __ push(rax);
       // Push global receiver.
-        __ movq(rbx, GlobalObjectOperand());
-        __ push(FieldOperand(rbx, GlobalObject::kGlobalReceiverOffset));
-        __ bind(&call);
+      __ movq(rbx, GlobalObjectOperand());
+      __ push(FieldOperand(rbx, GlobalObject::kGlobalReceiverOffset));
+      __ bind(&call);
     }
 
-    EmitCallWithStub(expr);
+    // The receiver is either the global receiver or a JSObject found by
+    // LoadContextSlot.
+    EmitCallWithStub(expr, NO_CALL_FUNCTION_FLAGS);
   } else if (fun->AsProperty() != NULL) {
     // Call to an object property.
     Property* prop = fun->AsProperty();
     Literal* key = prop->key()->AsLiteral();
     if (key != NULL && key->handle()->IsSymbol()) {
       // Call to a named property, use call IC.
       { PreservePositionScope scope(masm()->positions_recorder());
         VisitForStackValue(prop->obj());
       }
       EmitCallWithIC(expr, key->handle(), RelocInfo::CODE_TARGET);
@@ skipping 17 matching lines @@
         // Record source code position for IC call.
         SetSourcePosition(prop->position());
 
         Handle<Code> ic = isolate()->builtins()->KeyedLoadIC_Initialize();
         EmitCallIC(ic, RelocInfo::CODE_TARGET, GetPropertyId(prop));
         // Push result (function).
         __ push(rax);
         // Push Global receiver.
         __ movq(rcx, GlobalObjectOperand());
         __ push(FieldOperand(rcx, GlobalObject::kGlobalReceiverOffset));
-        EmitCallWithStub(expr);
+        EmitCallWithStub(expr, NO_CALL_FUNCTION_FLAGS);
       } else {
         { PreservePositionScope scope(masm()->positions_recorder());
           VisitForStackValue(prop->obj());
         }
         EmitKeyedCallWithIC(expr, prop->key(), RelocInfo::CODE_TARGET);
       }
     }
   } else {
     { PreservePositionScope scope(masm()->positions_recorder());
       VisitForStackValue(fun);
     }
     // Load global receiver object.
     __ movq(rbx, GlobalObjectOperand());
     __ push(FieldOperand(rbx, GlobalObject::kGlobalReceiverOffset));
     // Emit function call.
-    EmitCallWithStub(expr);
+    EmitCallWithStub(expr, NO_CALL_FUNCTION_FLAGS);
   }
 
 #ifdef DEBUG
   // RecordJSReturnSite should have been called.
   ASSERT(expr->return_is_recorded_);
 #endif
 }
 
 
 void FullCodeGenerator::VisitCallNew(CallNew* expr) {
@@ skipping 2041 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64