Check that environments assigned via AssignEnvironment are actually used.

src/arm/lithium-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 605 matching lines @@
 
   // If instruction does not have side-effects lazy deoptimization
   // after the call will try to deoptimize to the point before the call.
   // Thus we still need to attach environment to this call even if
   // call sequence can not deoptimize eagerly.
   bool needs_environment =
       (can_deoptimize == CAN_DEOPTIMIZE_EAGERLY) ||
       !hinstr->HasObservableSideEffects();
   if (needs_environment && !instr->HasEnvironment()) {
     instr = AssignEnvironment(instr);
+    // We can't really figure out if the environment is needed or not.
+    instr->environment()->set_has_been_used();
   }
 
   return instr;
 }
 
 
 LInstruction* LChunkBuilder::AssignPointerMap(LInstruction* instr) {
   ASSERT(!instr->HasPointerMap());
   instr->set_pointer_map(new(zone()) LPointerMap(zone()));
   return instr;
@@ skipping 1252 matching lines @@
       ASSERT(to.IsInteger32());
       if (val->type().IsSmi() || val->representation().IsSmi()) {
         LOperand* value = UseRegisterAtStart(val);
         return DefineAsRegister(new(zone()) LSmiUntag(value, false));
       } else {
         LOperand* value = UseRegister(val);
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = FixedTemp(d11);
         LInstruction* result =
             DefineSameAsFirst(new(zone()) LTaggedToI(value, temp1, temp2));
-        if (!val->representation().IsSmi()) {
-          // Note: Only deopts in deferred code.
-          result = AssignEnvironment(result);
-        }
+        if (!val->representation().IsSmi()) result = AssignEnvironment(result);
         return result;
       }
     }
   } else if (from.IsDouble()) {
     if (to.IsTagged()) {
       info()->MarkAsDeferredCalling();
       LOperand* value = UseRegister(val);
       LOperand* temp1 = TempRegister();
       LOperand* temp2 = TempRegister();
       LUnallocated* result_temp = TempRegister();
@@ skipping 74 matching lines @@
   return AssignEnvironment(new(zone()) LCheckValue(value));
 }
 
 
 LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
   LOperand* value = NULL;
   if (!instr->CanOmitMapChecks()) {
     value = UseRegisterAtStart(instr->value());
     if (instr->has_migration_target()) info()->MarkAsDeferredCalling();
   }
-  LCheckMaps* result = new(zone()) LCheckMaps(value);
+  LInstruction* result = new(zone()) LCheckMaps(value);
   if (!instr->CanOmitMapChecks()) {
-    // Note: Only deopts in deferred code.
-    AssignEnvironment(result);
-    if (instr->has_migration_target()) return AssignPointerMap(result);
+    result = AssignEnvironment(result);
+    if (instr->has_migration_target()) result = AssignPointerMap(result);
   }
   return result;
 }
 
 
 LInstruction* LChunkBuilder::DoClampToUint8(HClampToUint8* instr) {
   HValue* value = instr->value();
   Representation input_rep = value->representation();
   LOperand* reg = UseRegister(value);
   if (input_rep.IsDouble()) {
@@ skipping 560 matching lines @@
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 } }  // namespace v8::internal