Supporting AllocationSiteInfo for Nested arrays

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index a18f894b00c00bba1809f3e6407b66cf17d1a3f8..4ad819ab8b12ba5dc46f5d6c7a6b8331e7ff8181 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -5444,13 +5444,18 @@ void LCodeGen::DoArrayLiteral(LArrayLiteral* instr) {
     DeoptimizeIf(ne, instr->environment());
   }
 
+  int flags = allocation_site_mode == TRACK_ALLOCATION_SITE
+      ? ArrayLiteral::kAllocationSiteInfoAllowed
+      : ArrayLiteral::kNoFlags;
+
   // Set up the parameters to the stub/runtime call.
-  __ LoadHeapObject(r3, literals);
-  __ mov(r2, Operand(Smi::FromInt(instr->hydrogen()->literal_index())));
+  __ LoadHeapObject(r4, literals);
+  __ mov(r3, Operand(Smi::FromInt(instr->hydrogen()->literal_index())));
   // Boilerplate already exists, constant elements are never accessed.
   // Pass an empty fixed array.
-  __ mov(r1, Operand(isolate()->factory()->empty_fixed_array()));
-  __ Push(r3, r2, r1);
+  __ mov(r2, Operand(isolate()->factory()->empty_fixed_array()));
+  __ mov(r1, Operand(Smi::FromInt(flags)));
+  __ Push(r4, r3, r2, r1);
 
   // Pick the right runtime function or stub to call.
   int length = instr->hydrogen()->length();
@@ -5461,9 +5466,9 @@ void LCodeGen::DoArrayLiteral(LArrayLiteral* instr) {
     FastCloneShallowArrayStub stub(mode, DONT_TRACK_ALLOCATION_SITE, length);
     CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
   } else if (instr->hydrogen()->depth() > 1) {
-    CallRuntime(Runtime::kCreateArrayLiteral, 3, instr);
+    CallRuntime(Runtime::kCreateArrayLiteral, 4, instr);
   } else if (length > FastCloneShallowArrayStub::kMaximumClonedLength) {
-    CallRuntime(Runtime::kCreateArrayLiteralShallow, 3, instr);
+    CallRuntime(Runtime::kCreateArrayLiteralShallow, 4, instr);
   } else {
     FastCloneShallowArrayStub::Mode mode =
         boilerplate_elements_kind == FAST_DOUBLE_ELEMENTS
@@ -5476,6 +5481,7 @@ void LCodeGen::DoArrayLiteral(LArrayLiteral* instr) {
 
 
 void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
+                            Handle<JSObject> original_object,
                             Register result,
                             Register source,
                             int* offset,
@@ -5483,11 +5489,18 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
   ASSERT(!source.is(r2));
   ASSERT(!result.is(r2));
 
+  // Should we track allocation info for *this* object in the tree?
   bool create_allocation_site_info = mode == TRACK_ALLOCATION_SITE &&
       object->map()->CanTrackAllocationSite();
 
+  if (create_allocation_site_info && object->IsJSArray()) {
+    create_allocation_site_info = AllocationSiteInfo::GetMode(
+        object->GetElementsKind()) == TRACK_ALLOCATION_SITE;
+  }
+
   // Only elements backing stores for non-COW arrays need to be copied.
   Handle<FixedArrayBase> elements(object->elements());
+  Handle<FixedArrayBase> original_elements(original_object->elements());
   bool has_elements = elements->length() > 0 &&
       elements->map() != isolate()->heap()->fixed_cow_array_map();
 
@@ -5523,11 +5536,14 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
     Handle<Object> value = Handle<Object>(object->InObjectPropertyAt(i));
     if (value->IsJSObject()) {
       Handle<JSObject> value_object = Handle<JSObject>::cast(value);
+      Handle<JSObject> original_value_object = Handle<JSObject>::cast(
+          Handle<Object>(original_object->InObjectPropertyAt(i)));
+
       __ add(r2, result, Operand(*offset));
       __ str(r2, FieldMemOperand(result, total_offset));
       __ LoadHeapObject(source, value_object);
-      EmitDeepCopy(value_object, result, source, offset,
-                   DONT_TRACK_ALLOCATION_SITE);
+      EmitDeepCopy(value_object, original_value_object, result, source,
+                   offset, mode);
     } else if (value->IsHeapObject()) {
       __ LoadHeapObject(r2, Handle<HeapObject>::cast(value));
       __ str(r2, FieldMemOperand(result, total_offset));
@@ -5541,8 +5557,10 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
   if (create_allocation_site_info) {
     __ mov(r2, Operand(Handle<Map>(isolate()->heap()->
                                    allocation_site_info_map())));
-    __ str(r2, FieldMemOperand(result, object_size));
-    __ str(source, FieldMemOperand(result, object_size + kPointerSize));
+    __ str(r2, FieldMemOperand(result, object_size + object_offset));
+    __ LoadHeapObject(r2, original_object);
+    __ str(r2, FieldMemOperand(result,
+                               object_size + object_offset + kPointerSize));
   }
 
   if (has_elements) {
@@ -5572,16 +5590,26 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
       }
     } else if (elements->IsFixedArray()) {
       Handle<FixedArray> fast_elements = Handle<FixedArray>::cast(elements);
+      Handle<FixedArray> original_fast_elements =
+          Handle<FixedArray>::cast(original_elements);
       for (int i = 0; i < elements_length; i++) {
         int total_offset = elements_offset + FixedArray::OffsetOfElementAt(i);
         Handle<Object> value(fast_elements->get(i));
         if (value->IsJSObject()) {
           Handle<JSObject> value_object = Handle<JSObject>::cast(value);
+          Handle<JSObject> original_value_object = Handle<JSObject>::cast(
+              Handle<Object>(original_fast_elements->get(i)));
           __ add(r2, result, Operand(*offset));
           __ str(r2, FieldMemOperand(result, total_offset));
           __ LoadHeapObject(source, value_object);
-          EmitDeepCopy(value_object, result, source, offset,
-                       DONT_TRACK_ALLOCATION_SITE);
+
+          // TODO(mvstanton): do we have to worry that the original object
+          // changed from a fixed array to a fixeddoublearray? If that happened
+          // then the original_value_object expression might point to garbage
+          // memory, right?

[danno, 2013/02/08 13:44:38]

No, I don't think so, since if the array already contained objects at this
level, it must have already been FAST_ELEMENTS of some form, which would prevent
it from transition to double. You can add an assert above somewhere that
ASSERT(original_object->HasFastObjectElements()) and remove this comment.

[mvstanton, 2013/02/11 11:11:24]

Good point, thx.

+          ASSERT(!value_object.is_identical_to(original_value_object));
+          EmitDeepCopy(value_object, original_value_object, result, source,
+                       offset, mode);
         } else if (value->IsHeapObject()) {
           __ LoadHeapObject(r2, Handle<HeapObject>::cast(value));
           __ str(r2, FieldMemOperand(result, total_offset));
@@ -5599,26 +5627,7 @@ void LCodeGen::EmitDeepCopy(Handle<JSObject> object,
 
 void LCodeGen::DoFastLiteral(LFastLiteral* instr) {
   int size = instr->hydrogen()->total_size();
-  ElementsKind boilerplate_elements_kind =
-      instr->hydrogen()->boilerplate()->GetElementsKind();
-
-  // 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());
-  }
 
-  // Allocate all objects that are part of the literal in one big
   // allocation. This avoids multiple limit checks.
   Label allocated, runtime_allocate;
   __ AllocateInNewSpace(size, r0, r2, r3, &runtime_allocate, TAG_OBJECT);
@@ -5632,7 +5641,9 @@ void LCodeGen::DoFastLiteral(LFastLiteral* instr) {
   __ bind(&allocated);
   int offset = 0;
   __ LoadHeapObject(r1, instr->hydrogen()->boilerplate());
-  EmitDeepCopy(instr->hydrogen()->boilerplate(), r0, r1, &offset,
+  EmitDeepCopy(instr->hydrogen()->boilerplate(),
+               instr->hydrogen()->original_boilerplate(),
+               r0, r1, &offset,
                instr->hydrogen()->allocation_site_mode());
   ASSERT_EQ(size, offset);
 }
@@ -5650,6 +5661,11 @@ void LCodeGen::DoObjectLiteral(LObjectLiteral* instr) {
   int flags = instr->hydrogen()->fast_elements()
       ? ObjectLiteral::kFastElements
       : ObjectLiteral::kNoFlags;
+
+  if (instr->hydrogen()->allocation_site_mode() == TRACK_ALLOCATION_SITE) {
+    flags |= ObjectLiteral::kAllocationSiteInfoAllowed;
+  }
+
   __ mov(r1, Operand(Smi::FromInt(flags)));
   __ Push(r4, r3, r2, r1);