Convert fast smi-only to fast object in generated code for array push.

src/arm/stub-cache-arm.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 @@
   CheckPrototypes(Handle<JSObject>::cast(object), receiver, holder, r3, r0, r4,
                   name, &miss);
 
   if (argc == 0) {
     // Nothing to do, just return the length.
     __ ldr(r0, FieldMemOperand(receiver, JSArray::kLengthOffset));
     __ Drop(argc + 1);
     __ Ret();
   } else {
     Label call_builtin;
-    Register elements = r3;
-    Register end_elements = r5;
-    // Get the elements array of the object.
-    __ ldr(elements, FieldMemOperand(receiver, JSArray::kElementsOffset));
-
-    // Check that the elements are in fast mode and writable.
-    __ CheckMap(elements,
-                r0,
-                Heap::kFixedArrayMapRootIndex,
-                &call_builtin,
-                DONT_DO_SMI_CHECK);
 
     if (argc == 1) {  // Otherwise fall through to call the builtin.
       Label attempt_to_grow_elements;
 
+      Register elements = r6;
+      Register end_elements = r5;
+      // Get the elements array of the object.
+      __ ldr(elements, FieldMemOperand(receiver, JSArray::kElementsOffset));
+
+      // Check that the elements are in fast mode and writable.
+      __ CheckMap(elements,
+                  r0,
+                  Heap::kFixedArrayMapRootIndex,
+                  &call_builtin,
+                  DONT_DO_SMI_CHECK);
+
+
       // Get the array's length into r0 and calculate new length.
       __ ldr(r0, FieldMemOperand(receiver, JSArray::kLengthOffset));
       STATIC_ASSERT(kSmiTagSize == 1);
       STATIC_ASSERT(kSmiTag == 0);
       __ add(r0, r0, Operand(Smi::FromInt(argc)));
 
       // Get the element's length.
       __ ldr(r4, FieldMemOperand(elements, FixedArray::kLengthOffset));
 
       // Check if we could survive without allocation.
@@ skipping 16 matching lines @@
       const int kEndElementsOffset =
           FixedArray::kHeaderSize - kHeapObjectTag - argc * kPointerSize;
       __ str(r4, MemOperand(end_elements, kEndElementsOffset, PreIndex));
 
       // Check for a smi.
       __ Drop(argc + 1);
       __ Ret();
 
       __ bind(&with_write_barrier);
 
-      __ ldr(r6, FieldMemOperand(receiver, HeapObject::kMapOffset));
-      __ CheckFastObjectElements(r6, r6, &call_builtin);
+      __ ldr(r3, FieldMemOperand(receiver, HeapObject::kMapOffset));
+
+      if (FLAG_smi_only_arrays  && !FLAG_trace_elements_transitions) {
+        Label fast_object, not_fast_object;
+        __ CheckFastObjectElements(r3, r7, &not_fast_object);
+        __ jmp(&fast_object);
+        // In case of fast smi-only, convert to fast object, otherwise bail out.
+        __ bind(&not_fast_object);
+        __ CheckFastSmiOnlyElements(r3, r7, &call_builtin);
+        // edx: receiver
+        // r3: map
+        __ LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
+                                               FAST_ELEMENTS,
+                                               r3,
+                                               r7,
+                                               &call_builtin);
+        __ mov(r2, r1);

[Jakob Kummerow, 2012/02/08 16:24:55]

nit: s/r1/receiver/

+        ElementsTransitionGenerator::GenerateSmiOnlyToObject(masm());
+        __ bind(&fast_object);
+      } else {
+        __ CheckFastObjectElements(r3, r3, &call_builtin);
+      }
 
       // Save new length.
       __ str(r0, FieldMemOperand(receiver, JSArray::kLengthOffset));
 
       // Push the element.
       // We may need a register containing the address end_elements below,
       // so write back the value in end_elements.
       __ add(end_elements, elements,
              Operand(r0, LSL, kPointerSizeLog2 - kSmiTagSize));
       __ str(r4, MemOperand(end_elements, kEndElementsOffset, PreIndex));
@@ skipping 30 matching lines @@
           ExternalReference::new_space_allocation_top_address(isolate);
       ExternalReference new_space_allocation_limit =
           ExternalReference::new_space_allocation_limit_address(isolate);
 
       const int kAllocationDelta = 4;
       // Load top and check if it is the end of elements.
       __ add(end_elements, elements,
              Operand(r0, LSL, kPointerSizeLog2 - kSmiTagSize));
       __ add(end_elements, end_elements, Operand(kEndElementsOffset));
       __ mov(r7, Operand(new_space_allocation_top));
-      __ ldr(r6, MemOperand(r7));
-      __ cmp(end_elements, r6);
+      __ ldr(r3, MemOperand(r7));
+      __ cmp(end_elements, r3);
       __ b(ne, &call_builtin);
 
       __ mov(r9, Operand(new_space_allocation_limit));
       __ ldr(r9, MemOperand(r9));
-      __ add(r6, r6, Operand(kAllocationDelta * kPointerSize));
-      __ cmp(r6, r9);
+      __ add(r3, r3, Operand(kAllocationDelta * kPointerSize));
+      __ cmp(r3, r9);
       __ b(hi, &call_builtin);
 
       // We fit and could grow elements.
       // Update new_space_allocation_top.
-      __ str(r6, MemOperand(r7));
+      __ str(r3, MemOperand(r7));
       // Push the argument.
       __ str(r2, MemOperand(end_elements));
       // Fill the rest with holes.
-      __ LoadRoot(r6, Heap::kTheHoleValueRootIndex);
+      __ LoadRoot(r3, Heap::kTheHoleValueRootIndex);
       for (int i = 1; i < kAllocationDelta; i++) {
-        __ str(r6, MemOperand(end_elements, i * kPointerSize));
+        __ str(r3, MemOperand(end_elements, i * kPointerSize));
       }
 
       // Update elements' and array's sizes.
       __ str(r0, FieldMemOperand(receiver, JSArray::kLengthOffset));
       __ add(r4, r4, Operand(Smi::FromInt(kAllocationDelta)));
       __ str(r4, FieldMemOperand(elements, FixedArray::kLengthOffset));
 
       // Elements are in new space, so write barrier is not required.
       __ Drop(argc + 1);
       __ Ret();
@@ skipping 2636 matching lines @@
   Handle<Code> ic_miss = masm->isolate()->builtins()->KeyedStoreIC_Miss();
   __ Jump(ic_miss, RelocInfo::CODE_TARGET);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM