Implement tracking and optimizations of packed arrays

src/arm/lithium-codegen-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 2678 matching lines @@
     __ LoadRoot(ip, Heap::kFixedArrayMapRootIndex);
     __ cmp(scratch, ip);
     __ b(eq, &done);
     __ LoadRoot(ip, Heap::kFixedCOWArrayMapRootIndex);
     __ cmp(scratch, ip);
     __ b(eq, &done);
     // |scratch| still contains |input|'s map.
     __ ldr(scratch, FieldMemOperand(scratch, Map::kBitField2Offset));
     __ ubfx(scratch, scratch, Map::kElementsKindShift,
             Map::kElementsKindBitCount);
-    __ cmp(scratch, Operand(FAST_ELEMENTS));
-    __ b(eq, &done);
+    __ cmp(scratch, Operand(GetInitialFastElementsKind()));
+    __ b(lt, &fail);
+    __ cmp(scratch, Operand(TERMINAL_FAST_ELEMENTS_KIND));
+    __ b(le, &done);
     __ cmp(scratch, Operand(FIRST_EXTERNAL_ARRAY_ELEMENTS_KIND));
     __ b(lt, &fail);
     __ cmp(scratch, Operand(LAST_EXTERNAL_ARRAY_ELEMENTS_KIND));
     __ b(le, &done);
     __ bind(&fail);
     __ Abort("Check for fast or external elements failed.");
     __ bind(&done);
   }
 }
 
@@ skipping 67 matching lines @@
   Operand operand = key_is_constant
       ? Operand(constant_key * (1 << shift_size) +
                 FixedDoubleArray::kHeaderSize - kHeapObjectTag)
       : Operand(key, LSL, shift_size);
   __ add(elements, elements, operand);
   if (!key_is_constant) {
     __ add(elements, elements,
            Operand(FixedDoubleArray::kHeaderSize - kHeapObjectTag));
   }
 
-  __ ldr(scratch, MemOperand(elements, sizeof(kHoleNanLower32)));
-  __ cmp(scratch, Operand(kHoleNanUpper32));
-  DeoptimizeIf(eq, instr->environment());
+  if (instr->hydrogen()->RequiresHoleCheck()) {
+    __ ldr(scratch, MemOperand(elements, sizeof(kHoleNanLower32)));
+    __ cmp(scratch, Operand(kHoleNanUpper32));
+    DeoptimizeIf(eq, instr->environment());
+  }
 
   __ vldr(result, elements, 0);
 }
 
 
 void LCodeGen::DoLoadKeyedSpecializedArrayElement(
     LLoadKeyedSpecializedArrayElement* instr) {
   Register external_pointer = ToRegister(instr->external_pointer());
   Register key = no_reg;
   ElementsKind elements_kind = instr->elements_kind();
@@ skipping 48 matching lines @@
       case EXTERNAL_UNSIGNED_INT_ELEMENTS:
         __ ldr(result, mem_operand);
         __ cmp(result, Operand(0x80000000));
         // 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(cs, instr->environment());
         break;
       case EXTERNAL_FLOAT_ELEMENTS:
       case EXTERNAL_DOUBLE_ELEMENTS:
+      case FAST_HOLEY_DOUBLE_ELEMENTS:
+      case FAST_HOLEY_ELEMENTS:
+      case FAST_HOLEY_SMI_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
       case FAST_ELEMENTS:
-      case FAST_SMI_ONLY_ELEMENTS:
+      case FAST_SMI_ELEMENTS:
       case DICTIONARY_ELEMENTS:
       case NON_STRICT_ARGUMENTS_ELEMENTS:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoLoadKeyedGeneric(LLoadKeyedGeneric* instr) {
@@ skipping 968 matching lines @@
         __ strh(value, mem_operand);
         break;
       case EXTERNAL_INT_ELEMENTS:
       case EXTERNAL_UNSIGNED_INT_ELEMENTS:
         __ str(value, mem_operand);
         break;
       case EXTERNAL_FLOAT_ELEMENTS:
       case EXTERNAL_DOUBLE_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
       case FAST_ELEMENTS:
-      case FAST_SMI_ONLY_ELEMENTS:
+      case FAST_SMI_ELEMENTS:
+      case FAST_HOLEY_DOUBLE_ELEMENTS:
+      case FAST_HOLEY_ELEMENTS:
+      case FAST_HOLEY_SMI_ELEMENTS:
       case DICTIONARY_ELEMENTS:
       case NON_STRICT_ARGUMENTS_ELEMENTS:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoStoreKeyedGeneric(LStoreKeyedGeneric* instr) {
@@ skipping 16 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;
   __ ldr(scratch, FieldMemOperand(object_reg, HeapObject::kMapOffset));
   __ cmp(scratch, Operand(from_map));
   __ b(ne, &not_applicable);
   __ mov(new_map_reg, Operand(to_map));
-  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) {
     __ str(new_map_reg, FieldMemOperand(object_reg, HeapObject::kMapOffset));
     // Write barrier.
     __ RecordWriteField(object_reg, HeapObject::kMapOffset, new_map_reg,
                         scratch, kLRHasBeenSaved, 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(r2));
     ASSERT(new_map_reg.is(r3));
     __ mov(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(r2));
     ASSERT(new_map_reg.is(r3));
     __ mov(fixed_object_reg, object_reg);
     CallCode(isolate()->builtins()->TransitionElementsDoubleToObject(),
              RelocInfo::CODE_TARGET, instr);
   } else {
     UNREACHABLE();
   }
   __ bind(&not_applicable);
@@ skipping 753 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(r1, instr->hydrogen()->boilerplate_object());
     // Load map into r2.
     __ ldr(r2, FieldMemOperand(r1, HeapObject::kMapOffset));
     // Load the map's "bit field 2".
     __ ldrb(r2, FieldMemOperand(r2, Map::kBitField2Offset));
     // Retrieve elements_kind from bit field 2.
     __ ubfx(r2, r2, Map::kElementsKindShift, Map::kElementsKindBitCount);
     __ cmp(r2, Operand(boilerplate_elements_kind));
     DeoptimizeIf(ne, instr->environment());
   }
@@ skipping 130 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 TERMINAL_FAST_ELEMENTS_KIND.
+  if (CanTransitionToMoreGeneralFastElementsKind(
+          boilerplate_elements_kind, true)) {
     __ LoadHeapObject(r1, instr->hydrogen()->boilerplate());
     // Load map into r2.
     __ ldr(r2, FieldMemOperand(r1, HeapObject::kMapOffset));
     // Load the map's "bit field 2".
     __ ldrb(r2, FieldMemOperand(r2, Map::kBitField2Offset));
     // Retrieve elements_kind from bit field 2.
     __ ubfx(r2, r2, Map::kElementsKindShift, Map::kElementsKindBitCount);
     __ cmp(r2, Operand(boilerplate_elements_kind));
     DeoptimizeIf(ne, instr->environment());
   }
@@ skipping 467 matching lines @@
   __ sub(scratch, result, Operand(index, LSL, kPointerSizeLog2 - kSmiTagSize));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal