Implement tracking and optimizations of packed arrays

src/x64/lithium-codegen-x64.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 2306 matching lines @@
     __ j(equal, &done, Label::kNear);
     __ CompareRoot(FieldOperand(result, HeapObject::kMapOffset),
                    Heap::kFixedCOWArrayMapRootIndex);
     __ j(equal, &done, Label::kNear);
     Register temp((result.is(rax)) ? rbx : rax);
     __ push(temp);
     __ movq(temp, FieldOperand(result, HeapObject::kMapOffset));
     __ movzxbq(temp, FieldOperand(temp, Map::kBitField2Offset));
     __ and_(temp, Immediate(Map::kElementsKindMask));
     __ shr(temp, Immediate(Map::kElementsKindShift));
-    __ cmpl(temp, Immediate(FAST_ELEMENTS));
-    __ j(equal, &ok, Label::kNear);
+    __ cmpl(temp, Immediate(GetInitialFastElementsKind()));
+    __ j(less, &fail, Label::kNear);
+    __ cmpl(temp, Immediate(TERMINAL_FAST_ELEMENTS_KIND));
+    __ j(less_equal, &ok, Label::kNear);
     __ cmpl(temp, Immediate(FIRST_EXTERNAL_ARRAY_ELEMENTS_KIND));
     __ j(less, &fail, Label::kNear);
     __ cmpl(temp, Immediate(LAST_EXTERNAL_ARRAY_ELEMENTS_KIND));
     __ j(less_equal, &ok, Label::kNear);
     __ bind(&fail);
     __ Abort("Check for fast or external elements failed");
     __ bind(&ok);
     __ pop(temp);
     __ bind(&done);
   }
@@ skipping 41 matching lines @@
     __ CompareRoot(result, Heap::kTheHoleValueRootIndex);
     DeoptimizeIf(equal, instr->environment());
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFastDoubleElement(
     LLoadKeyedFastDoubleElement* instr) {
   XMMRegister result(ToDoubleRegister(instr->result()));
 
-  int offset = FixedDoubleArray::kHeaderSize - kHeapObjectTag +
-      sizeof(kHoleNanLower32);
-  Operand hole_check_operand = BuildFastArrayOperand(
-      instr->elements(),
-      instr->key(),
-      FAST_DOUBLE_ELEMENTS,
-      offset);
-  __ cmpl(hole_check_operand, Immediate(kHoleNanUpper32));
-  DeoptimizeIf(equal, instr->environment());
+  if (instr->hydrogen()->RequiresHoleCheck()) {
+    int offset = FixedDoubleArray::kHeaderSize - kHeapObjectTag +
+        sizeof(kHoleNanLower32);
+    Operand hole_check_operand = BuildFastArrayOperand(
+        instr->elements(),
+        instr->key(),
+        FAST_DOUBLE_ELEMENTS,
+        offset);
+    __ cmpl(hole_check_operand, Immediate(kHoleNanUpper32));
+    DeoptimizeIf(equal, instr->environment());
+  }
 
   Operand double_load_operand = BuildFastArrayOperand(
       instr->elements(), instr->key(), FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag);
   __ movsd(result, double_load_operand);
 }
 
 
 Operand LCodeGen::BuildFastArrayOperand(
     LOperand* elements_pointer,
@@ skipping 51 matching lines @@
         __ movl(result, operand);
         __ testl(result, result);
         // TODO(danno): we could be more clever here, perhaps having a special
         // version of the stub that detects if the overflow case actually
         // happens, and generate code that returns a double rather than int.
         DeoptimizeIf(negative, instr->environment());
         break;
       case EXTERNAL_FLOAT_ELEMENTS:
       case EXTERNAL_DOUBLE_ELEMENTS:
       case FAST_ELEMENTS:
-      case FAST_SMI_ONLY_ELEMENTS:
+      case FAST_SMI_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
+      case FAST_HOLEY_ELEMENTS:
+      case FAST_HOLEY_SMI_ELEMENTS:
+      case FAST_HOLEY_DOUBLE_ELEMENTS:
       case DICTIONARY_ELEMENTS:
       case NON_STRICT_ARGUMENTS_ELEMENTS:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoLoadKeyedGeneric(LLoadKeyedGeneric* instr) {
@@ skipping 869 matching lines @@
       case EXTERNAL_UNSIGNED_SHORT_ELEMENTS:
         __ movw(operand, value);
         break;
       case EXTERNAL_INT_ELEMENTS:
       case EXTERNAL_UNSIGNED_INT_ELEMENTS:
         __ movl(operand, value);
         break;
       case EXTERNAL_FLOAT_ELEMENTS:
       case EXTERNAL_DOUBLE_ELEMENTS:
       case FAST_ELEMENTS:
-      case FAST_SMI_ONLY_ELEMENTS:
+      case FAST_SMI_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
+      case FAST_HOLEY_ELEMENTS:
+      case FAST_HOLEY_SMI_ELEMENTS:
+      case FAST_HOLEY_DOUBLE_ELEMENTS:
       case DICTIONARY_ELEMENTS:
       case NON_STRICT_ARGUMENTS_ELEMENTS:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
@@ skipping 104 matching lines @@
 
   Handle<Map> from_map = instr->original_map();
   Handle<Map> to_map = instr->transitioned_map();
   ElementsKind from_kind = from_map->elements_kind();
   ElementsKind to_kind = to_map->elements_kind();
 
   Label not_applicable;
   __ Cmp(FieldOperand(object_reg, HeapObject::kMapOffset), from_map);
   __ j(not_equal, &not_applicable);
   __ movq(new_map_reg, to_map, RelocInfo::EMBEDDED_OBJECT);
-  if (from_kind == FAST_SMI_ONLY_ELEMENTS && to_kind == FAST_ELEMENTS) {
+  bool simple_map_change = (GetHoleyElementsKind(from_kind) == to_kind) ||
+      (IsFastSmiElementsKind(from_kind) &&
+       IsFastObjectElementsKind(to_kind));
+  if (simple_map_change) {
     __ movq(FieldOperand(object_reg, HeapObject::kMapOffset), new_map_reg);
     // Write barrier.
     ASSERT_NE(instr->temp_reg(), NULL);
     __ RecordWriteField(object_reg, HeapObject::kMapOffset, new_map_reg,
                         ToRegister(instr->temp_reg()), kDontSaveFPRegs);
-  } else if (from_kind == FAST_SMI_ONLY_ELEMENTS &&
-      to_kind == FAST_DOUBLE_ELEMENTS) {
+  } else if (IsFastSmiElementsKind(from_kind) &&
+             IsFastDoubleElementsKind(to_kind)) {
     Register fixed_object_reg = ToRegister(instr->temp_reg());
     ASSERT(fixed_object_reg.is(rdx));
     ASSERT(new_map_reg.is(rbx));
     __ movq(fixed_object_reg, object_reg);
     CallCode(isolate()->builtins()->TransitionElementsSmiToDouble(),
              RelocInfo::CODE_TARGET, instr);
-  } else if (from_kind == FAST_DOUBLE_ELEMENTS && to_kind == FAST_ELEMENTS) {
+  } else if (IsFastDoubleElementsKind(from_kind) &&
+             IsFastElementsKind(to_kind)) {

[Jakob Kummerow, 2012/05/22 17:36:49]

IsFastObjectElementsKind(to_kind) ?

[danno, 2012/05/23 14:25:36]

Done.

     Register fixed_object_reg = ToRegister(instr->temp_reg());
     ASSERT(fixed_object_reg.is(rdx));
     ASSERT(new_map_reg.is(rbx));
     __ movq(fixed_object_reg, object_reg);
     CallCode(isolate()->builtins()->TransitionElementsDoubleToObject(),
              RelocInfo::CODE_TARGET, instr);
   } else {
     UNREACHABLE();
   }
   __ bind(&not_applicable);
@@ skipping 653 matching lines @@
 }
 
 
 void LCodeGen::DoArrayLiteral(LArrayLiteral* instr) {
   Heap* heap = isolate()->heap();
   ElementsKind boilerplate_elements_kind =
       instr->hydrogen()->boilerplate_elements_kind();
 
   // Deopt if the array literal boilerplate ElementsKind is of a type different
   // than the expected one. The check isn't necessary if the boilerplate has
-  // already been converted to FAST_ELEMENTS.
-  if (boilerplate_elements_kind != FAST_ELEMENTS) {
+  // already been converted to TERMINAL_FAST_ELEMENTS_KIND.
+  if (CanTransitionToMoreGeneralFastElementsKind(
+          boilerplate_elements_kind, true)) {
     __ LoadHeapObject(rax, instr->hydrogen()->boilerplate_object());
     __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
     // Load the map's "bit field 2".
     __ movb(rbx, FieldOperand(rbx, Map::kBitField2Offset));
     // Retrieve elements_kind from bit field 2.
     __ and_(rbx, Immediate(Map::kElementsKindMask));
     __ cmpb(rbx, Immediate(boilerplate_elements_kind <<
                            Map::kElementsKindShift));
     DeoptimizeIf(not_equal, instr->environment());
   }
@@ skipping 125 matching lines @@
     }
   }
 }
 
 
 void LCodeGen::DoFastLiteral(LFastLiteral* instr) {
   int size = instr->hydrogen()->total_size();
   ElementsKind boilerplate_elements_kind =
       instr->hydrogen()->boilerplate()->GetElementsKind();
 
-  // Deopt if the literal boilerplate ElementsKind is of a type different than
-  // the expected one. The check isn't necessary if the boilerplate has already
-  // been converted to FAST_ELEMENTS.
-  if (boilerplate_elements_kind != FAST_ELEMENTS) {
+  // Deopt if the array literal boilerplate ElementsKind is of a type different
+  // than the expected one. The check isn't necessary if the boilerplate has
+  // already been converted to FAST_ELEMENTS.

[Jakob Kummerow, 2012/05/22 17:36:49]

nit: s/FAST_ELEMENTS/TERMINAL_FAST_ELEMENTS_KIND/

[danno, 2012/05/23 14:25:36]

Done.

+  if (CanTransitionToMoreGeneralFastElementsKind(
+          boilerplate_elements_kind, true)) {
     __ LoadHeapObject(rbx, instr->hydrogen()->boilerplate());
     __ movq(rcx, FieldOperand(rbx, HeapObject::kMapOffset));
     // Load the map's "bit field 2".
     __ movb(rcx, FieldOperand(rcx, Map::kBitField2Offset));
     // Retrieve elements_kind from bit field 2.
     __ and_(rcx, Immediate(Map::kElementsKindMask));
     __ cmpb(rcx, Immediate(boilerplate_elements_kind <<
                            Map::kElementsKindShift));
     DeoptimizeIf(not_equal, instr->environment());
   }
@@ skipping 475 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64