Deletion barrier: Distinguish+verify field initialization in ia32 generated code.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 42713)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -3425,7 +3425,8 @@
         offset_in_bytes_(field.Offset()),
         emit_store_barrier_(emit_store_barrier),
         token_pos_(token_pos),
-        is_initialization_(false) {
+        is_potential_unboxed_initialization_(false),
+        is_object_reference_initialization_(false) {
     SetInputAt(kInstancePos, instance);
     SetInputAt(kValuePos, value);
   }
@@ -3439,7 +3440,8 @@
         offset_in_bytes_(offset_in_bytes),
         emit_store_barrier_(emit_store_barrier),
         token_pos_(token_pos),
-        is_initialization_(false) {
+        is_potential_unboxed_initialization_(false),
+        is_object_reference_initialization_(false) {
     SetInputAt(kInstancePos, instance);
     SetInputAt(kValuePos, value);
   }
@@ -3446,7 +3448,12 @@
 
   DECLARE_INSTRUCTION(StoreInstanceField)
 
-  void set_is_initialization(bool value) { is_initialization_ = value; }
+  void set_is_potential_unboxed_initialization(bool value) {
+    is_potential_unboxed_initialization_ = value;
+  }
+  void set_is_object_reference_initialization(bool value) {
+    is_object_reference_initialization_ = value;
+  }
 
   enum {
     kInstancePos = 0,
@@ -3455,7 +3462,12 @@
 
   Value* instance() const { return inputs_[kInstancePos]; }
   Value* value() const { return inputs_[kValuePos]; }
-  bool is_initialization() const { return is_initialization_; }
+  bool is_potential_unboxed_initialization() const {
+    return is_potential_unboxed_initialization_;
+  }
+  bool is_object_reference_initialization() const {
+    return is_object_reference_initialization_;
+  }
   virtual intptr_t token_pos() const { return token_pos_; }
 
   const Field& field() const { return field_; }
@@ -3500,7 +3512,11 @@
   intptr_t offset_in_bytes_;
   const StoreBarrierType emit_store_barrier_;
   const intptr_t token_pos_;
-  bool is_initialization_;  // Marks stores in the constructor.
+  // This may be the first store to an unboxed field.
+  bool is_potential_unboxed_initialization_;
+  // True if this store initializes an object reference field of an object that
+  // was allocated uninitialized; see AllocateUninitializedContext.
+  bool is_object_reference_initialization_;
 
   DISALLOW_COPY_AND_ASSIGN(StoreInstanceFieldInstr);
 };