Remove unused byte from Map::instance_sizes field.

src/arm/builtins-arm.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 "src/v8.h"
 
 #if V8_TARGET_ARCH_ARM
 
 #include "src/codegen.h"
 #include "src/debug.h"
@@ skipping 367 matching lines @@
     __ b(eq, &normal_new);
 
     // Original constructor and function are different.
     Generate_Runtime_NewObject(masm, create_memento, r3, &count_incremented,
                                &allocated);
     __ bind(&normal_new);
 
     // Try to allocate the object without transitioning into C code. If any of
     // the preconditions is not met, the code bails out to the runtime call.
     if (FLAG_inline_new) {
-      Label undo_allocation;
       ExternalReference debug_step_in_fp =
           ExternalReference::debug_step_in_fp_address(isolate);
       __ mov(r2, Operand(debug_step_in_fp));
       __ ldr(r2, MemOperand(r2));
       __ tst(r2, r2);
       __ b(ne, &rt_call);
 
       // Load the initial map and verify that it is in fact a map.
       // r1: constructor function
       __ ldr(r2, FieldMemOperand(r1, JSFunction::kPrototypeOrInitialMapOffset));
@@ skipping 72 matching lines @@
         Label no_inobject_slack_tracking;
 
         // Check if slack tracking is enabled.
         __ ldr(ip, FieldMemOperand(r2, Map::kBitField3Offset));
         __ DecodeField<Map::Counter>(ip);
         __ cmp(ip, Operand(Map::kSlackTrackingCounterEnd));
         __ b(lt, &no_inobject_slack_tracking);
 
         // Allocate object with a slack.
         __ ldr(r0, FieldMemOperand(r2, Map::kInstanceSizesOffset));
-        __ Ubfx(r0, r0, Map::kPreAllocatedPropertyFieldsByte * kBitsPerByte,
+        __ Ubfx(r0, r0, Map::kInObjectPropertiesByte * kBitsPerByte,
                 kBitsPerByte);
+        __ ldr(r2, FieldMemOperand(r2, Map::kInstanceAttributesOffset));
+        __ Ubfx(r2, r2, Map::kUnusedPropertyFieldsByte * kBitsPerByte,
+                kBitsPerByte);
+        __ sub(r0, r0, Operand(r2));
         __ add(r0, r5, Operand(r0, LSL, kPointerSizeLog2));
         // r0: offset of first field after pre-allocated fields
         if (FLAG_debug_code) {
           __ add(ip, r4, Operand(r3, LSL, kPointerSizeLog2));  // End of object.
           __ cmp(r0, ip);
           __ Assert(le, kUnexpectedNumberOfPreAllocatedPropertyFields);
         }
         __ InitializeFieldsWithFiller(r5, r0, r6);
         // To allow for truncation.
         __ LoadRoot(r6, Heap::kOnePointerFillerMapRootIndex);
@@ skipping 15 matching lines @@
         // Load the AllocationSite
         __ ldr(r6, MemOperand(sp, 2 * kPointerSize));
         DCHECK_EQ(1 * kPointerSize, AllocationMemento::kAllocationSiteOffset);
         __ str(r6, MemOperand(r5, kPointerSize, PostIndex));
       } else {
         __ add(r0, r4, Operand(r3, LSL, kPointerSizeLog2));  // End of object.
         __ InitializeFieldsWithFiller(r5, r0, r6);
       }
 
       // Add the object tag to make the JSObject real, so that we can continue
-      // and jump into the continuation code at any time from now on. Any
-      // failures need to undo the allocation, so that the heap is in a
-      // consistent state and verifiable.
+      // and jump into the continuation code at any time from now on.
       __ add(r4, r4, Operand(kHeapObjectTag));
 
-      // Check if a non-empty properties array is needed. Continue with
-      // allocated object if not; allocate and initialize a FixedArray if yes.
-      // r1: constructor function
-      // r4: JSObject
-      // r5: start of next object (not tagged)
-      __ ldrb(r3, FieldMemOperand(r2, Map::kUnusedPropertyFieldsOffset));
-      // The field instance sizes contains both pre-allocated property fields
-      // and in-object properties.
-      __ ldr(r0, FieldMemOperand(r2, Map::kInstanceSizesOffset));
-      __ Ubfx(r6, r0, Map::kPreAllocatedPropertyFieldsByte * kBitsPerByte,
-              kBitsPerByte);
-      __ add(r3, r3, Operand(r6));
-      __ Ubfx(r6, r0, Map::kInObjectPropertiesByte * kBitsPerByte,
-              kBitsPerByte);
-      __ sub(r3, r3, Operand(r6), SetCC);
-
-      // Done if no extra properties are to be allocated.
-      __ b(eq, &allocated);
-      __ Assert(pl, kPropertyAllocationCountFailed);
-
-      // Scale the number of elements by pointer size and add the header for
-      // FixedArrays to the start of the next object calculation from above.
-      // r1: constructor
-      // r3: number of elements in properties array
-      // r4: JSObject
-      // r5: start of next object
-      __ add(r0, r3, Operand(FixedArray::kHeaderSize / kPointerSize));
-      __ Allocate(
-          r0,
-          r5,
-          r6,
-          r2,
-          &undo_allocation,
-          static_cast<AllocationFlags>(RESULT_CONTAINS_TOP | SIZE_IN_WORDS));
-
-      // Initialize the FixedArray.
-      // r1: constructor
-      // r3: number of elements in properties array
-      // r4: JSObject
-      // r5: FixedArray (not tagged)
-      __ LoadRoot(r6, Heap::kFixedArrayMapRootIndex);
-      __ mov(r2, r5);
-      DCHECK_EQ(0 * kPointerSize, JSObject::kMapOffset);
-      __ str(r6, MemOperand(r2, kPointerSize, PostIndex));
-      DCHECK_EQ(1 * kPointerSize, FixedArray::kLengthOffset);
-      __ SmiTag(r0, r3);
-      __ str(r0, MemOperand(r2, kPointerSize, PostIndex));
-
-      // Initialize the fields to undefined.
-      // r1: constructor function
-      // r2: First element of FixedArray (not tagged)
-      // r3: number of elements in properties array
-      // r4: JSObject
-      // r5: FixedArray (not tagged)
-      __ add(r6, r2, Operand(r3, LSL, kPointerSizeLog2));  // End of object.
-      DCHECK_EQ(2 * kPointerSize, FixedArray::kHeaderSize);
-      __ LoadRoot(r0, Heap::kUndefinedValueRootIndex);
-      __ InitializeFieldsWithFiller(r2, r6, r0);
-
-      // Store the initialized FixedArray into the properties field of
-      // the JSObject
-      // r1: constructor function
-      // r4: JSObject
-      // r5: FixedArray (not tagged)
-      __ add(r5, r5, Operand(kHeapObjectTag));  // Add the heap tag.
-      __ str(r5, FieldMemOperand(r4, JSObject::kPropertiesOffset));
-
       // Continue with JSObject being successfully allocated
-      // r1: constructor function
       // r4: JSObject
       __ jmp(&allocated);
-
-      // Undo the setting of the new top so that the heap is verifiable. For
-      // example, the map's unused properties potentially do not match the
-      // allocated objects unused properties.
-      // r4: JSObject (previous new top)
-      __ bind(&undo_allocation);
-      __ UndoAllocationInNewSpace(r4, r5);
     }
 
     // Allocate the new receiver object using the runtime call.
     // r1: constructor function
     __ bind(&rt_call);
     Generate_Runtime_NewObject(masm, create_memento, r1, &count_incremented,
                                &allocated);
 
     // Receiver for constructor call allocated.
     // r4: JSObject
@@ skipping 1202 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM