Allocation Info Tracking, continued.

src/ia32/builtins-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 1457 matching lines @@
   __ bind(&generic_array_code);
   Handle<Code> array_code =
       masm->isolate()->builtins()->ArrayCodeGeneric();
   __ jmp(array_code, RelocInfo::CODE_TARGET);
 }
 
 
 void Builtins::Generate_ArrayConstructCode(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- eax : argc
+  //  -- ebx : type info cell
+  //  -- edi : constructor
+  //  -- esp[0] : return address
+  //  -- esp[4] : last argument
+  // -----------------------------------
+  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, "Unexpected initial map for Array function");
+    __ CmpObjectType(ecx, MAP_TYPE, ecx);
+    __ Assert(equal, "Unexpected initial map for Array function");
+
+    // We should either have undefined in ebx or a valid jsglobalpropertycell
+    Label okay_here;
+    Handle<Object> undefined_sentinel(
+        masm->isolate()->heap()->undefined_value());
+    Handle<Map> global_property_cell_map(
+        masm->isolate()->heap()->global_property_cell_map());
+    __ cmp(ebx, Immediate(undefined_sentinel));
+    __ j(equal, &okay_here);
+    __ cmp(FieldOperand(ebx, 0), Immediate(global_property_cell_map));
+    __ Assert(equal, "Expected property cell in register ebx");
+    __ bind(&okay_here);
+  }
+
+  if (FLAG_optimize_constructed_arrays) {

[Toon Verwaest, 2013/02/13 15:14:51]

Given that the 2 blocks of code are entirely independent, I'd split up this
function into 2 functions; and move the if to wherever this function is being
called.

[mvstanton, 2013/02/19 11:04:08]

Actually I'd like to keep it this way because in the following checkin, the
FLAG_optimize_constructed_arrays will be removed...it just exists for this
checkin to hide the (not yet performant) feature. This function is exactly the
bottleneck for that feature.

Also, I would have to make a new built-in, because this function isn't called
directly, it's called under a kArrayConstructCode key.

+    Label not_zero_case, not_one_case;
+    __ test(eax, eax);
+    __ j(not_zero, &not_zero_case);
+    ArrayNoArgumentConstructorStub no_argument_stub;
+    __ TailCallStub(&no_argument_stub);
+
+    __ bind(&not_zero_case);
+    __ cmp(eax, 1);
+    __ j(greater, &not_one_case);
+    ArraySingleArgumentConstructorStub single_argument_stub;
+    __ TailCallStub(&single_argument_stub);
+
+    __ bind(&not_one_case);
+    ArrayNArgumentsConstructorStub n_argument_stub;
+    __ TailCallStub(&n_argument_stub);
+  } else {
+    Label generic_constructor;
+    // Run the native code for the Array function called as constructor.
+    ArrayNativeCode(masm, true, &generic_constructor);
+
+    // Jump to the generic construct code in case the specialized code cannot
+    // handle the construction.
+    __ bind(&generic_constructor);
+    Handle<Code> generic_construct_stub =
+        masm->isolate()->builtins()->JSConstructStubGeneric();
+    __ jmp(generic_construct_stub, RelocInfo::CODE_TARGET);
+  }
+}
+
+
+void Builtins::Generate_InternalArrayConstructCode(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- eax : argc
   //  -- edi : constructor
   //  -- esp[0] : return address
   //  -- esp[4] : last argument
   // -----------------------------------
   Label generic_constructor;
 
   if (FLAG_debug_code) {
     // The array construct code is only set for the global and natives
     // builtin Array functions which always have maps.
 
@@ skipping 336 matching lines @@
   Deoptimizer::EntryGenerator generator(masm, Deoptimizer::OSR);
   generator.Generate();
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32