Check that environments assigned via AssignEnvironment are actually used.

src/arm64/lithium-arm64.cc

 // Copyright 2013 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 497 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 572 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 = instr->CanTruncateToInt32() ? NULL : FixedTemp(d24);
         LInstruction* result =
             DefineAsRegister(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();
       LNumberTagD* result = new(zone()) LNumberTagD(value, temp1, temp2);
@@ skipping 63 matching lines @@
 LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
   LOperand* value = NULL;
   LOperand* temp = NULL;
   if (!instr->CanOmitMapChecks()) {
     value = UseRegisterAtStart(instr->value());
     temp = TempRegister();
     if (instr->has_migration_target()) info()->MarkAsDeferredCalling();
   }
   LInstruction* result = new(zone()) LCheckMaps(value, temp);
   if (!instr->CanOmitMapChecks()) {
-    // Note: Only deopts in deferred code.
     result = AssignEnvironment(result);
-    if (instr->has_migration_target()) return AssignPointerMap(result);
+    if (instr->has_migration_target()) result = AssignPointerMap(result);
   }
   return result;
 }
 
 
 LInstruction* LChunkBuilder::DoCheckHeapObject(HCheckHeapObject* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   return AssignEnvironment(new(zone()) LCheckNonSmi(value));
 }
 
@@ skipping 1215 matching lines @@
       if (r.IsTagged()) {
         // The tagged case might need to allocate a HeapNumber for the result,
         // so it is handled by a separate LInstruction.
         LOperand* context = UseFixed(instr->context(), cp);
         LOperand* input = UseRegister(instr->value());
         LOperand* temp1 = TempRegister();
         LOperand* temp2 = TempRegister();
         LOperand* temp3 = TempRegister();
         LInstruction* result = DefineAsRegister(
             new(zone()) LMathAbsTagged(context, input, temp1, temp2, temp3));
-        // Note: Only deopts in deferred code.
         return AssignEnvironment(AssignPointerMap(result));
       } else {
         LOperand* input = UseRegisterAtStart(instr->value());
         LInstruction* result = DefineAsRegister(new(zone()) LMathAbs(input));
         if (!r.IsDouble()) result = AssignEnvironment(result);
         return result;
       }
     }
     case kMathExp: {
       ASSERT(instr->representation().IsDouble());
@@ skipping 118 matching lines @@
 
 LInstruction* LChunkBuilder::DoWrapReceiver(HWrapReceiver* instr) {
   LOperand* receiver = UseRegister(instr->receiver());
   LOperand* function = UseRegister(instr->function());
   LWrapReceiver* result = new(zone()) LWrapReceiver(receiver, function);
   return AssignEnvironment(DefineAsRegister(result));
 }
 
 
 } }  // namespace v8::internal