From 1fbec40a7fd156f097e700e638df6cdc3fdb8eb4 Mon Sep 17 00:00:00 2001
From: "fschneider@google.com" <fschneider@google.com>
Date: Tue, 4 Mar 2014 11:53:16 +0000
Subject: [PATCH] Change deoptimization description for materialized objects.

Use field offset instead of fields as arguments in the deoptimization
instructions for materialization of objects. This is to prepare for
materializing contexts and fixed-size arrays when doing allocation sinking.

R=johnmccutchan@google.com

Review URL: https://codereview.chromium.org//183683013

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@33267 260f80e4-7a28-3924-810f-c04153c831b5
---
 runtime/vm/deferred_objects.cc     | 14 ++++++++++++--
 runtime/vm/deferred_objects.h      |  6 +++---
 runtime/vm/deopt_instructions.cc   |  5 +++--
 runtime/vm/intermediate_language.h |  4 ++--
 runtime/vm/object.h                |  1 +
 5 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/runtime/vm/deferred_objects.cc b/runtime/vm/deferred_objects.cc
index ab9e6cdc61a..3632b92b877 100644
--- a/runtime/vm/deferred_objects.cc
+++ b/runtime/vm/deferred_objects.cc
@@ -116,12 +116,22 @@ void DeferredObject::Materialize() {
 
   const Instance& obj = Instance::ZoneHandle(Instance::New(cls));
 
+  Smi& offset = Smi::Handle();
   Field& field = Field::Handle();
   Object& value = Object::Handle();
+  const Array& offset_map = Array::Handle(cls.OffsetToFieldMap());
+
   for (intptr_t i = 0; i < field_count_; i++) {
-    field ^= GetField(i);
+    offset ^= GetFieldOffset(i);
+    field ^= offset_map.At(offset.Value() / kWordSize);
     value = GetValue(i);
-    obj.SetField(field, value);
+    if (!field.IsNull()) {
+      obj.SetField(field, value);
+    } else {
+      ASSERT(cls.IsSignatureClass() ||
+             (offset.Value() == cls.type_arguments_field_offset()));
+      obj.SetFieldAtOffset(offset.Value(), value);
+    }
 
     if (FLAG_trace_deoptimization_verbose) {
       OS::PrintErr("    %s <- %s\n",
diff --git a/runtime/vm/deferred_objects.h b/runtime/vm/deferred_objects.h
index 2e0733c4c9a..9619d16e5ab 100644
--- a/runtime/vm/deferred_objects.h
+++ b/runtime/vm/deferred_objects.h
@@ -164,7 +164,7 @@ class DeferredObject {
   };
 
   enum {
-    kFieldIndex = 0,
+    kOffsetIndex = 0,
     kValueIndex,
     kFieldEntrySize,
   };
@@ -178,8 +178,8 @@ class DeferredObject {
     return args_[kClassIndex];
   }
 
-  RawObject* GetField(intptr_t index) const {
-    return args_[kFieldsStartIndex + kFieldEntrySize * index + kFieldIndex];
+  RawObject* GetFieldOffset(intptr_t index) const {
+    return args_[kFieldsStartIndex + kFieldEntrySize * index + kOffsetIndex];
   }
 
   RawObject* GetValue(intptr_t index) const {
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index 9dca795b39a..14ca863d449 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -1377,8 +1377,9 @@ intptr_t DeoptInfoBuilder::EmitMaterializationArguments(intptr_t dest_index) {
     AddConstant(mat->cls(), dest_index++);
     for (intptr_t i = 0; i < mat->InputCount(); i++) {
       if (!mat->InputAt(i)->BindsToConstantNull()) {
-        // Emit field-value pair.
-        AddConstant(mat->FieldAt(i), dest_index++);
+        // Emit offset-value pair.
+        AddConstant(Smi::Handle(Smi::New(mat->FieldOffsetAt(i))),
+                    dest_index++);
         AddCopy(mat->InputAt(i), mat->LocationAt(i), dest_index++);
       }
     }
diff --git a/runtime/vm/intermediate_language.h b/runtime/vm/intermediate_language.h
index 880408840b1..117a816eb86 100644
--- a/runtime/vm/intermediate_language.h
+++ b/runtime/vm/intermediate_language.h
@@ -4073,8 +4073,8 @@ class MaterializeObjectInstr : public Definition {
   }
 
   const Class& cls() const { return cls_; }
-  const Field& FieldAt(intptr_t i) const {
-    return *fields_[i];
+  intptr_t FieldOffsetAt(intptr_t i) const {
+    return fields_[i]->Offset();
   }
   const Location& LocationAt(intptr_t i) {
     return locations_[i];
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index ddd5ce162d0..3747a39664b 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -4060,6 +4060,7 @@ class Instance : public Object {
   friend class SnapshotWriter;
   friend class StubCode;
   friend class TypedDataView;
+  friend class DeferredObject;
 };