Implement tracking and optimizations of packed arrays

src/mips/macro-assembler-mips.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 3323 matching lines @@
   sw(filler, MemOperand(start_offset));
   Addu(start_offset, start_offset, kPointerSize);
   bind(&entry);
   Branch(&loop, lt, start_offset, Operand(end_offset));
 }
 
 
 void MacroAssembler::CheckFastElements(Register map,
                                        Register scratch,
                                        Label* fail) {
-  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
-  STATIC_ASSERT(FAST_ELEMENTS == 1);
+  STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
+  STATIC_ASSERT(FAST_ELEMENTS == 2);
+  STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
   lbu(scratch, FieldMemOperand(map, Map::kBitField2Offset));
-  Branch(fail, hi, scratch, Operand(Map::kMaximumBitField2FastElementValue));
+  Branch(fail, hi, scratch,
+         Operand(Map::kMaximumBitField2FastHoleyElementValue));
 }
 
 
 void MacroAssembler::CheckFastObjectElements(Register map,
                                              Register scratch,
                                              Label* fail) {
-  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
-  STATIC_ASSERT(FAST_ELEMENTS == 1);
+  STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
+  STATIC_ASSERT(FAST_ELEMENTS == 2);
+  STATIC_ASSERT(FAST_HOLEY_ELEMENTS == 3);
   lbu(scratch, FieldMemOperand(map, Map::kBitField2Offset));
   Branch(fail, ls, scratch,
-         Operand(Map::kMaximumBitField2FastSmiOnlyElementValue));
+         Operand(Map::kMaximumBitField2FastHoleySmiElementValue));
   Branch(fail, hi, scratch,
-         Operand(Map::kMaximumBitField2FastElementValue));
+         Operand(Map::kMaximumBitField2FastHoleyElementValue));
 }
 
 
-void MacroAssembler::CheckFastSmiOnlyElements(Register map,
-                                              Register scratch,
-                                              Label* fail) {
-  STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
+void MacroAssembler::CheckFastSmiElements(Register map,
+                                          Register scratch,
+                                          Label* fail) {
+  STATIC_ASSERT(FAST_SMI_ELEMENTS == 0);
+  STATIC_ASSERT(FAST_HOLEY_SMI_ELEMENTS == 1);
   lbu(scratch, FieldMemOperand(map, Map::kBitField2Offset));
   Branch(fail, hi, scratch,
-         Operand(Map::kMaximumBitField2FastSmiOnlyElementValue));
+         Operand(Map::kMaximumBitField2FastHoleySmiElementValue));
 }
 
 
 void MacroAssembler::StoreNumberToDoubleElements(Register value_reg,
                                                  Register key_reg,
                                                  Register receiver_reg,
                                                  Register elements_reg,
                                                  Register scratch1,
                                                  Register scratch2,
                                                  Register scratch3,
@@ skipping 81 matching lines @@
 void MacroAssembler::CompareMapAndBranch(Register obj,
                                          Register scratch,
                                          Handle<Map> map,
                                          Label* early_success,
                                          Condition cond,
                                          Label* branch_to,
                                          CompareMapMode mode) {
   lw(scratch, FieldMemOperand(obj, HeapObject::kMapOffset));
   Operand right = Operand(map);
   if (mode == ALLOW_ELEMENT_TRANSITION_MAPS) {
-    Map* transitioned_fast_element_map(
-        map->LookupElementsTransitionMap(FAST_ELEMENTS, NULL));
-    ASSERT(transitioned_fast_element_map == NULL ||
-           map->elements_kind() != FAST_ELEMENTS);
-    if (transitioned_fast_element_map != NULL) {
-      Branch(early_success, eq, scratch, right);
-      right = Operand(Handle<Map>(transitioned_fast_element_map));
-    }
-
-    Map* transitioned_double_map(
-        map->LookupElementsTransitionMap(FAST_DOUBLE_ELEMENTS, NULL));
-    ASSERT(transitioned_double_map == NULL ||
-           map->elements_kind() == FAST_SMI_ONLY_ELEMENTS);
-    if (transitioned_double_map != NULL) {
-      Branch(early_success, eq, scratch, right);
-      right = Operand(Handle<Map>(transitioned_double_map));
+    ElementsKind kind = map->elements_kind();
+    if (IsFastElementsKind(kind)) {
+      bool packed = IsFastPackedElementsKind(kind);
+      Map* current_map = *map;
+      while (CanTransitionToMoreGeneralFastElementsKind(kind, packed)) {
+        kind = GetNextMoreGeneralFastElementsKind(kind, packed);
+        current_map = current_map->LookupElementsTransitionMap(kind, NULL);
+        if (!current_map) break;
+        Branch(early_success, eq, scratch, right);
+        right = Operand(Handle<Map>(current_map));
+      }
     }
   }
 
   Branch(branch_to, cond, scratch, right);
 }
 
 
 void MacroAssembler::CheckMap(Register obj,
                               Register scratch,
                               Handle<Map> map,
@@ skipping 938 matching lines @@
     ElementsKind expected_kind,
     ElementsKind transitioned_kind,
     Register map_in_out,
     Register scratch,
     Label* no_map_match) {
   // Load the global or builtins object from the current context.
   lw(scratch, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
   lw(scratch, FieldMemOperand(scratch, GlobalObject::kGlobalContextOffset));
 
   // Check that the function's map is the same as the expected cached map.
-  int expected_index =
-      Context::GetContextMapIndexFromElementsKind(expected_kind);
-  lw(at, MemOperand(scratch, Context::SlotOffset(expected_index)));
-  Branch(no_map_match, ne, map_in_out, Operand(at));
+  lw(scratch,
+     MemOperand(scratch,
+                Context::SlotOffset(Context::JS_ARRAY_MAPS_INDEX)));
+  size_t offset = expected_kind * kPointerSize +
+      FixedArrayBase::kHeaderSize;
+  Branch(no_map_match, ne, map_in_out, Operand(scratch));
 
   // Use the transitioned cached map.
-  int trans_index =
-      Context::GetContextMapIndexFromElementsKind(transitioned_kind);
-  lw(map_in_out, MemOperand(scratch, Context::SlotOffset(trans_index)));
+  offset = transitioned_kind * kPointerSize +
+      FixedArrayBase::kHeaderSize;
+  lw(map_in_out, FieldMemOperand(scratch, offset));
 }
 
 
 void MacroAssembler::LoadInitialArrayMap(
-    Register function_in, Register scratch, Register map_out) {
+    Register function_in, Register scratch,
+    Register map_out, bool can_have_holes) {
   ASSERT(!function_in.is(map_out));
   Label done;
   lw(map_out, FieldMemOperand(function_in,
                               JSFunction::kPrototypeOrInitialMapOffset));
   if (!FLAG_smi_only_arrays) {
-    LoadTransitionedArrayMapConditional(FAST_SMI_ONLY_ELEMENTS,
-                                        FAST_ELEMENTS,
+    ElementsKind kind = can_have_holes ? FAST_HOLEY_ELEMENTS : FAST_ELEMENTS;
+    LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS,
+                                        kind,
                                         map_out,
                                         scratch,
                                         &done);
+  } else if (can_have_holes) {
+    LoadTransitionedArrayMapConditional(FAST_SMI_ELEMENTS,
+                                        FAST_HOLEY_SMI_ELEMENTS,
+                                        map_out,
+                                        scratch,
+                                        &done);
   }
   bind(&done);
 }
 
 
 void MacroAssembler::LoadGlobalFunction(int index, Register function) {
   // Load the global or builtins object from the current context.
   lw(function, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
   // Load the global context from the global or builtins object.
   lw(function, FieldMemOperand(function,
@@ skipping 944 matching lines @@
        opcode == BGTZL);
   opcode = (cond == eq) ? BEQ : BNE;
   instr = (instr & ~kOpcodeMask) | opcode;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS