Symbols for type cells.

src/ia32/code-stubs-ia32.cc

 // Copyright 2012 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 2405 matching lines @@
   __ pop(edx);
   __ pop(ebx);
   __ pop(edi);
 
   __ bind(&done);
 }
 
 
 void CallFunctionStub::Generate(MacroAssembler* masm) {
   // ebx : feedback vector
-  // edx : (only if ebx is not undefined) slot in feedback vector (Smi)
+  // edx : (only if ebx is not the megamorphic symbol) slot in feedback
+  //       vector (Smi)
   // edi : the function to call
   Isolate* isolate = masm->isolate();
   Label slow, non_function, wrap, cont;
 
   if (NeedsChecks()) {
     // Check that the function really is a JavaScript function.
     __ JumpIfSmi(edi, &non_function);
 
     // Goto slow case if we do not have a function.
     __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
@@ skipping 37 matching lines @@
   }
 
   __ InvokeFunction(edi, actual, JUMP_FUNCTION, NullCallWrapper());
 
   if (NeedsChecks()) {
     // Slow-case: Non-function called.
     __ bind(&slow);
     if (RecordCallTarget()) {
       // If there is a call target cache, mark it megamorphic in the
       // non-function case.  MegamorphicSentinel is an immortal immovable
-      // object (undefined) so no write barrier is needed.
+      // object (megamorphic symbol) so no write barrier is needed.
       __ mov(FieldOperand(ebx, edx, times_half_pointer_size,
                           FixedArray::kHeaderSize),
              Immediate(TypeFeedbackInfo::MegamorphicSentinel(isolate)));
     }
     // Check for function proxy.
     __ CmpInstanceType(ecx, JS_FUNCTION_PROXY_TYPE);
     __ j(not_equal, &non_function);
     __ pop(ecx);
     __ push(edi);  // put proxy as additional argument under return address
     __ push(ecx);
@@ skipping 27 matching lines @@
     }
     __ mov(Operand(esp, (argc_ + 1) * kPointerSize), eax);
     __ jmp(&cont);
   }
 }
 
 
 void CallConstructStub::Generate(MacroAssembler* masm) {
   // eax : number of arguments
   // ebx : feedback vector
-  // edx : (only if ebx is not undefined) slot in feedback vector (Smi)
+  // edx : (only if ebx is not the megamorphic symbol) slot in feedback
+  //       vector (Smi)
   // edi : constructor function
   Label slow, non_function_call;
 
   // Check that function is not a smi.
   __ JumpIfSmi(edi, &non_function_call);
   // Check that function is a JSFunction.
   __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
   __ j(not_equal, &slow);
 
   if (RecordCallTarget()) {
@@ skipping 2602 matching lines @@
     CreateArrayDispatch<ArrayNArgumentsConstructorStub>(masm, mode);
   } else {
     UNREACHABLE();
   }
 }
 
 
 void ArrayConstructorStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- eax : argc (only if argument_count_ == ANY)
-  //  -- ebx : feedback vector (fixed array or undefined)
+  //  -- ebx : feedback vector (fixed array or megamorphic symbol)
   //  -- edx : slot index (if ebx is fixed array)
   //  -- edi : constructor
   //  -- esp[0] : return address
   //  -- esp[4] : last argument
   // -----------------------------------
-  Handle<Object> undefined_sentinel(
-      masm->isolate()->heap()->undefined_value(),
-      masm->isolate());
+  Handle<Object> megamorphic_sentinel =
+      TypeFeedbackInfo::MegamorphicSentinel(masm->isolate());
 
   if (FLAG_debug_code) {
     // The array construct code is only set for the global and natives
     // builtin Array functions which always have maps.
 
     // Initial map for the builtin Array function should be a map.
     __ mov(ecx, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
     // Will both indicate a NULL and a Smi.
     __ test(ecx, Immediate(kSmiTagMask));
     __ Assert(not_zero, kUnexpectedInitialMapForArrayFunction);
     __ CmpObjectType(ecx, MAP_TYPE, ecx);
     __ Assert(equal, kUnexpectedInitialMapForArrayFunction);
 
-    // We should either have undefined in ebx or a valid fixed array.
+    // We should either have the megamorphic symbol in ebx or a valid
+    // fixed array.
     Label okay_here;
     Handle<Map> fixed_array_map = masm->isolate()->factory()->fixed_array_map();
-    __ cmp(ebx, Immediate(undefined_sentinel));
+    __ cmp(ebx, Immediate(megamorphic_sentinel));
     __ j(equal, &okay_here);
     __ cmp(FieldOperand(ebx, 0), Immediate(fixed_array_map));
     __ Assert(equal, kExpectedFixedArrayInRegisterEbx);
 
-    // edx should be a smi if we don't have undefined in ebx.
+    // edx should be a smi if we don't have the megamorphic symbol in ebx.
     __ AssertSmi(edx);
 
     __ bind(&okay_here);
   }
 
   Label no_info;
-  // If the feedback vector is undefined, or contains anything other than an
-  // AllocationSite, call an array constructor that doesn't use AllocationSites.
-  __ cmp(ebx, Immediate(undefined_sentinel));
+  // If the feedback vector is the megamorphic sentinel, or contains anything
+  // other than an AllocationSite, call an array constructor that doesn't use
+  // AllocationSites.
+  __ cmp(ebx, Immediate(megamorphic_sentinel));
   __ j(equal, &no_info);
   __ mov(ebx, FieldOperand(ebx, edx, times_half_pointer_size,
                            FixedArray::kHeaderSize));
   __ cmp(FieldOperand(ebx, 0), Immediate(
       masm->isolate()->factory()->allocation_site_map()));
   __ j(not_equal, &no_info);
 
   // Only look at the lower 16 bits of the transition info.
   __ mov(edx, FieldOperand(ebx, AllocationSite::kTransitionInfoOffset));
   __ SmiUntag(edx);
@@ skipping 250 matching lines @@
                               Operand(ebp, 7 * kPointerSize),
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32