Add a smi-check instruction for arithmetic smi operations.

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/hash_map.h"
 #include "vm/il_printer.h"
@@ skipping 16 matching lines @@
 
 
 void FlowGraphOptimizer::OptimizeComputations() {
   for (intptr_t i = 0; i < block_order_.length(); ++i) {
     BlockEntryInstr* entry = block_order_[i];
     entry->Accept(this);
     for (ForwardInstructionIterator it(entry); !it.Done(); it.Advance()) {
       BindInstr* instr = it.Current()->AsBind();
       if (instr != NULL) {
         Definition* result = instr->computation()->TryReplace(instr);
-        if (result != NULL) {
-          // Replace uses and remove the current instructions via the iterator.
-          instr->ReplaceUsesWith(result);
+        if (result != instr) {
+          if (result != NULL) {
+            instr->ReplaceUsesWith(result);
+            if (FLAG_trace_optimization) {
+              OS::Print("Replacing v%d with v%d\n",
+                        instr->ssa_temp_index(),
+                        result->ssa_temp_index());
+            }
+          } else if (FLAG_trace_optimization) {
+              OS::Print("Removing v%d.\n", instr->ssa_temp_index());
+          }
           it.RemoveCurrentFromGraph();
-          if (FLAG_trace_optimization) {
-            OS::Print("Replacing v%d with v%d\n",
-                      instr->ssa_temp_index(),
-                      result->ssa_temp_index());
-          }
         }
       }
     }
   }
 }
 
 
 static bool ICDataHasReceiverClassId(const ICData& ic_data, intptr_t class_id) {
   ASSERT(ic_data.num_args_tested() > 0);
   for (intptr_t i = 0; i < ic_data.NumberOfChecks(); i++) {
@@ skipping 131 matching lines @@
   if (ic_data.NumberOfChecks() != 1) return kIllegalCid;
   ASSERT(HasOneTarget(ic_data));
 
   Function& target = Function::Handle();
   intptr_t class_id;
   ic_data.GetOneClassCheckAt(0, &class_id, &target);
   return class_id;
 }
 
 
+// Insert a check computation before an instruction and set the environment
+// of the check to the same as the instruction.
+static void InsertCheckBefore(BindInstr* instr,
+                              Computation* check,
+                              Environment* env) {
+  BindInstr* check_instr = new BindInstr(BindInstr::kUnused, check);
+  check_instr->InsertBefore(instr);
+  ASSERT(env != NULL);
+  // Attach an environment to the check instruction.
+  check_instr->set_env(env);
+}
+
+
 static void AddCheckClass(BindInstr* instr,
                           InstanceCallComp* comp,
                           Value* value) {
   // Type propagation has not run yet, we cannot eliminate the check.
   CheckClassComp* check = new CheckClassComp(value, comp);
   const ICData& unary_checks =
       ICData::ZoneHandle(comp->ic_data()->AsUnaryClassChecks());
   check->set_ic_data(&unary_checks);
-  BindInstr* check_instr = new BindInstr(BindInstr::kUnused, check);
-  ASSERT(instr->env() != NULL);  // Always the case with SSA.
-  // Attach the original environment to the check instruction.
-  check_instr->set_env(instr->env());
-  check_instr->InsertBefore(instr);
+  InsertCheckBefore(instr, check, instr->env());
+  // Detach environment from the original instruction because it can't
+  // deoptimize.
+  instr->set_env(NULL);
 }
 
 
 bool FlowGraphOptimizer::TryReplaceWithArrayOp(BindInstr* instr,
                                                InstanceCallComp* comp,
                                                Token::Kind op_kind) {
   // TODO(fschneider): Optimize []= operator in checked mode as well.
   if (op_kind == Token::kASSIGN_INDEX && FLAG_enable_type_checks) return false;
 
   const intptr_t class_id = ReceiverClassId(comp);
@@ skipping 90 matching lines @@
                                                     comp,
                                                     left,
                                                     right);
     bin_op->set_ic_data(comp->ic_data());
     instr->set_computation(bin_op);
     RemovePushArguments(comp);
   } else {
     ASSERT(operands_type == kSmiCid);
     Value* left = comp->ArgumentAt(0)->value();
     Value* right = comp->ArgumentAt(1)->value();
+    // Insert two smi checks and attach a copy of the original
+    // environment because the smi operation can still deoptimize.
+    InsertCheckBefore(instr,
+                      new CheckSmiComp(left, comp),
+                      instr->env()->Copy());
+    InsertCheckBefore(instr,
+                      new CheckSmiComp(right, comp),
+                      instr->env()->Copy());
     BinarySmiOpComp* bin_op = new BinarySmiOpComp(op_kind,
                                                   comp,
                                                   left,
                                                   right);
     bin_op->set_ic_data(comp->ic_data());
     instr->set_computation(bin_op);
     RemovePushArguments(comp);
   }
   return true;
 }
@@ skipping 54 matching lines @@
   if (target.kind() == RawFunction::kImplicitGetter) {
     if (!HasOneTarget(ic_data)) {
       // TODO(srdjan): Implement for mutiple targets.
       return false;
     }
     // Inline implicit instance getter.
     const String& field_name =
         String::Handle(Field::NameFromGetter(comp->function_name()));
     const Field& field = Field::Handle(GetField(class_ids[0], field_name));
     ASSERT(!field.IsNull());
+
     AddCheckClass(instr, comp, comp->ArgumentAt(0)->value());
-    instr->set_env(NULL);
     LoadInstanceFieldComp* load =
         new LoadInstanceFieldComp(field,
                                   comp->ArgumentAt(0)->value(),
                                   NULL);  // Can not deoptimize.
     instr->set_computation(load);
     RemovePushArguments(comp);
     return true;
   }
 
   // Not an implicit getter.
@@ skipping 160 matching lines @@
     // TODO(srdjan): Inline special setters.
     return false;
   }
   // Inline implicit instance setter.
   const String& field_name =
       String::Handle(Field::NameFromSetter(comp->function_name()));
   const Field& field = Field::Handle(GetField(class_id, field_name));
   ASSERT(!field.IsNull());
 
   AddCheckClass(instr, comp, comp->ArgumentAt(0)->value());
-  instr->set_env(NULL);
   StoreInstanceFieldComp* store = new StoreInstanceFieldComp(
       field,
       comp->ArgumentAt(0)->value(),
       comp->ArgumentAt(1)->value(),
       NULL);  // Can not deoptimize.
   instr->set_computation(store);
   RemovePushArguments(comp);
   return true;
 }
 
@@ skipping 366 matching lines @@
         OS::Print("Replacing v%d with v%d\n",
                   instr->ssa_temp_index(),
                   result->ssa_temp_index());
       }
     }
   }
 }
 
 
 }  // namespace dart