X87: Remove receiver conversion from function prologue.

src/full-codegen/x87/full-codegen-x87.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.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
@@ skipping 87 matching lines @@
 
   ProfileEntryHookStub::MaybeCallEntryHook(masm_);
 
 #ifdef DEBUG
   if (strlen(FLAG_stop_at) > 0 &&
       literal()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
     __ int3();
   }
 #endif
 
-  // Sloppy mode functions and builtins need to replace the receiver with the
-  // global proxy when called as functions (without an explicit receiver
-  // object).
-  if (info->MustReplaceUndefinedReceiverWithGlobalProxy()) {
-    Label ok;
-    // +1 for return address.
+  if (FLAG_debug_code && info->ExpectsJSReceiverAsReceiver()) {
     int receiver_offset = (info->scope()->num_parameters() + 1) * kPointerSize;
     __ mov(ecx, Operand(esp, receiver_offset));
-
-    __ cmp(ecx, isolate()->factory()->undefined_value());
-    __ j(not_equal, &ok, Label::kNear);
-
-    __ mov(ecx, GlobalObjectOperand());
-    __ mov(ecx, FieldOperand(ecx, JSGlobalObject::kGlobalProxyOffset));
-
-    __ mov(Operand(esp, receiver_offset), ecx);
-
-    __ bind(&ok);
+    __ AssertNotSmi(ecx);
+    __ CmpObjectType(ecx, FIRST_SPEC_OBJECT_TYPE, ecx);
+    __ Assert(above_equal, kSloppyFunctionExpectsJSReceiverReceiver);
   }
 
   // Open a frame scope to indicate that there is a frame on the stack.  The
   // MANUAL indicates that the scope shouldn't actually generate code to set up
   // the frame (that is done below).
   FrameScope frame_scope(masm_, StackFrame::MANUAL);
 
   info->set_prologue_offset(masm_->pc_offset());
   __ Prologue(info->IsCodePreAgingActive());
 
@@ skipping 4825 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87