MIPS: Fix r21470 “Reland r21442 Inobject slack tracking is done on a per-closure basis instead of p…

src/mips/builtins-mips.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.
 
 
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
@@ skipping 361 matching lines @@
       __ Branch(&rt_call, ne, t4, Operand(MAP_TYPE));
 
       // Check that the constructor is not constructing a JSFunction (see
       // comments in Runtime_NewObject in runtime.cc). In which case the
       // initial map's instance type would be JS_FUNCTION_TYPE.
       // a1: constructor function
       // a2: initial map
       __ lbu(a3, FieldMemOperand(a2, Map::kInstanceTypeOffset));
       __ Branch(&rt_call, eq, a3, Operand(JS_FUNCTION_TYPE));
 
-      // Use t7 to hold undefined, which is used in several places below.
-      __ LoadRoot(t7, Heap::kUndefinedValueRootIndex);
-
       if (!is_api_function) {
         Label allocate;
         MemOperand bit_field3 = FieldMemOperand(a2, Map::kBitField3Offset);
         // Check if slack tracking is enabled.
         __ lw(t0, bit_field3);
         __ DecodeField<Map::ConstructionCount>(t2, t0);
         __ Branch(&allocate, eq, t2, Operand(JSFunction::kNoSlackTracking));
         // Decrease generous allocation count.
         __ Subu(t0, t0, Operand(1 << Map::ConstructionCount::kShift));
         __ Branch(USE_DELAY_SLOT,
             &allocate, ne, t2, Operand(JSFunction::kFinishSlackTracking));
         __ sw(t0, bit_field3);  // In delay slot.
 
         __ Push(a1, a2, a1);  // a1 = Constructor.
         __ CallRuntime(Runtime::kHiddenFinalizeInstanceSize, 1);
 
         __ Pop(a1, a2);
+        ASSERT(JSFunction::kNoSlackTracking == 0);
+        __ mov(t2, zero_reg);

[Paul Lind, 2014/05/23 19:18:05]

Can we add a comment here: // Slack tracking counter is 0 after runtime call.

[kilvadyb, 2014/05/23 19:30:38]

Done.

 
         __ bind(&allocate);
       }
 
       // Now allocate the JSObject on the heap.
       // a1: constructor function
       // a2: initial map
       __ lbu(a3, FieldMemOperand(a2, Map::kInstanceSizeOffset));
       if (create_memento) {
         __ Addu(a3, a3, Operand(AllocationMemento::kSize / kPointerSize));
@@ skipping 19 matching lines @@
 
       // Fill all the in-object properties with appropriate filler.
       // a1: constructor function
       // a2: initial map
       // a3: object size (in words, including memento if create_memento)
       // t4: JSObject (not tagged)
       // t5: First in-object property of JSObject (not tagged)
       // t2: slack tracking counter (non-API function case)
       ASSERT_EQ(3 * kPointerSize, JSObject::kHeaderSize);
 
+      // Use t7 to hold undefined, which is used in several places below.
+      __ LoadRoot(t7, Heap::kUndefinedValueRootIndex);
+
       if (!is_api_function) {
         Label no_inobject_slack_tracking;
 
         // Check if slack tracking is enabled.
         __ Branch(&no_inobject_slack_tracking,
             eq, t2, Operand(JSFunction::kNoSlackTracking));
 
         // Allocate object with a slack.
         __ lbu(a0, FieldMemOperand(a2, Map::kPreAllocatedPropertyFieldsOffset));
         __ sll(at, a0, kPointerSizeLog2);
@@ skipping 1117 matching lines @@
     __ break_(0xCC);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS