In background compilation make a copy of Field in order to freeze its state

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
diff --git a/runtime/vm/intermediate_language_mips.cc b/runtime/vm/intermediate_language_mips.cc
index 9055cccac6860e39bb5b86b93b96740038a6f72e..b018c9f2ad0f79d54e5fe2c0c8e2d15a11df47d9 100644
--- a/runtime/vm/intermediate_language_mips.cc
+++ b/runtime/vm/intermediate_language_mips.cc
@@ -1641,7 +1641,7 @@ void GuardFieldClassInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Label* fail = (deopt != NULL) ? deopt : &fail_label;
 
   if (emit_full_guard) {
-    __ LoadObject(field_reg, Field::ZoneHandle(field().raw()));
+    __ LoadObject(field_reg, Field::ZoneHandle(field().Original()));
 
     FieldAddress field_cid_operand(field_reg, Field::guarded_cid_offset());
     FieldAddress field_nullability_operand(
@@ -1786,7 +1786,7 @@ void GuardFieldLengthInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 
     Label ok;
 
-    __ LoadObject(field_reg, Field::ZoneHandle(field().raw()));
+    __ LoadObject(field_reg, Field::ZoneHandle(field().Original()));
 
     __ lb(CMPRES1, FieldAddress(field_reg,
         Field::guarded_list_length_in_object_offset_offset()));
@@ -2001,7 +2001,7 @@ void StoreInstanceFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     Label store_pointer;
     Label store_double;
 
-    __ LoadObject(temp, Field::ZoneHandle(field().raw()));
+    __ LoadObject(temp, *field().OriginalAsHandle(compiler->zone()));

[siva, 2016/02/25 23:38:33]

Ditto.

 
     __ lhu(temp2, FieldAddress(temp, Field::is_nullable_offset()));
     __ BranchEqual(temp2, Immediate(kNullCid), &store_pointer);
@@ -2107,7 +2107,7 @@ void StoreStaticFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register value = locs()->in(0).reg();
   Register temp = locs()->temp(0).reg();
 
-  __ LoadObject(temp, field());
+  __ LoadObject(temp, *field().OriginalAsHandle(compiler->zone()));

[siva, 2016/02/25 23:38:33]

Ditto.

   if (this->value()->NeedsStoreBuffer()) {
     __ StoreIntoObject(temp,
                        FieldAddress(temp, Field::static_value_offset()),
@@ -2317,7 +2317,7 @@ void LoadFieldInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     Label load_pointer;
     Label load_double;
 
-    __ LoadObject(result_reg, Field::ZoneHandle(field()->raw()));
+    __ LoadObject(result_reg, Field::ZoneHandle(field()->Original()));
 
     FieldAddress field_cid_operand(result_reg, Field::guarded_cid_offset());
     FieldAddress field_nullability_operand(result_reg,