Implement tracking and optimizations of packed arrays

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 2c2445b4c78dce6810639eac3b1c14b521b435b8..6cd5e97f62a61252299cbddd4755dff7e8fedccb 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -3341,33 +3341,39 @@ void MacroAssembler::InitializeFieldsWithFiller(Register start_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));
 }
 
 
@@ -3469,22 +3475,17 @@ void MacroAssembler::CompareMapAndBranch(Register obj,
   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));
+      }
     }
   }
 
@@ -4443,27 +4444,37 @@ void MacroAssembler::LoadTransitionedArrayMapConditional(
   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);