Store pointer instead of reference to LocalVariable in ast and flow graph.

runtime/vm/flow_graph_builder.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_builder.h"
 
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
@@ skipping 188 matching lines @@
 }
 
 
 PushArgumentInstr* EffectGraphVisitor::PushArgument(Value* value) {
   PushArgumentInstr* result = new PushArgumentInstr(value);
   AddInstruction(result);
   return result;
 }
 
 
-Computation* EffectGraphVisitor::BuildStoreLocal(
-    const LocalVariable& local, Value* value) {
-  if (local.is_captured()) {
+Computation* EffectGraphVisitor::BuildStoreLocal(const LocalVariable* local,
+                                                 Value* value) {
+  if (local->is_captured()) {
     intptr_t delta = owner()->context_level() -
-                     local.owner()->context_level();
+                     local->owner()->context_level();
     ASSERT(delta >= 0);
     Value* context = Bind(new CurrentContextComp());
     while (delta-- > 0) {
       context = Bind(new LoadVMFieldComp(
           context, Context::parent_offset(), Type::ZoneHandle()));
     }
     return new StoreVMFieldComp(
         context,
-        Context::variable_offset(local.index()),
+        Context::variable_offset(local->index()),
         value,
-        local.type());
+        local->type());
   } else {
     return new StoreLocalComp(local, value, owner()->context_level());
   }
 }
 
 
-Computation* EffectGraphVisitor::BuildLoadLocal(const LocalVariable& local) {
-  if (local.is_captured()) {
+Computation* EffectGraphVisitor::BuildLoadLocal(const LocalVariable* local) {
+  if (local->is_captured()) {
     intptr_t delta = owner()->context_level() -
-                     local.owner()->context_level();
+                     local->owner()->context_level();
     ASSERT(delta >= 0);
     Value* context = Bind(new CurrentContextComp());
     while (delta-- > 0) {
       context = Bind(new LoadVMFieldComp(
           context, Context::parent_offset(), Type::ZoneHandle()));
     }
     return new LoadVMFieldComp(context,
-                               Context::variable_offset(local.index()),
-                               local.type());
+                               Context::variable_offset(local->index()),
+                               local->type());
   } else {
     return new LoadLocalComp(local, owner()->context_level());
   }
 }
 
 
 // Stores current context into the 'variable'
-void EffectGraphVisitor::BuildStoreContext(const LocalVariable& variable) {
+void EffectGraphVisitor::BuildStoreContext(const LocalVariable* variable) {
   Value* context = Bind(new CurrentContextComp());
   Do(BuildStoreLocal(variable, context));
 }
 
 
 // Loads context saved in 'context_variable' into the current context.
-void EffectGraphVisitor::BuildLoadContext(const LocalVariable& variable) {
+void EffectGraphVisitor::BuildLoadContext(const LocalVariable* variable) {
   Value* load_saved_context = Bind(BuildLoadLocal(variable));
   Do(new StoreContextComp(load_saved_context));
 }
 
 
 void TestGraphVisitor::ReturnValue(Value* value) {
   if (FLAG_enable_type_checks) {
     value = Bind(new AssertBooleanComp(condition_token_pos(),
                                        owner()->try_index(),
                                        value));
@@ skipping 98 matching lines @@
                                           return_value,
                                           dst_type,
                                           dst_name);
     }
   }
 
   intptr_t current_context_level = owner()->context_level();
   ASSERT(current_context_level >= 0);
   if (owner()->parsed_function().saved_context_var() != NULL) {
     // CTX on entry was saved, but not linked as context parent.
-    BuildLoadContext(*owner()->parsed_function().saved_context_var());
+    BuildLoadContext(owner()->parsed_function().saved_context_var());
   } else {
     while (current_context_level-- > 0) {
       UnchainContext();
     }
   }
 
   AddInstruction(new ReturnInstr(node->token_pos(), return_value));
   CloseFragment();
 }
 
@@ skipping 152 matching lines @@
           for_right.Bind(new AssertBooleanComp(node->right()->token_pos(),
                                                owner()->try_index(),
                                                right_value));
     }
     Value* constant_true = for_right.Bind(new ConstantVal(bool_true));
     Value* compare =
         for_right.Bind(new StrictCompareComp(Token::kEQ_STRICT,
                                              right_value,
                                              constant_true));
     for_right.Do(BuildStoreLocal(
-        *owner()->parsed_function().expression_temp_var(),
+        owner()->parsed_function().expression_temp_var(),
         compare));
 
     if (node->kind() == Token::kAND) {
       ValueGraphVisitor for_false(owner(), temp_index());
       Value* constant_false = for_false.Bind(new ConstantVal(bool_false));
       for_false.Do(BuildStoreLocal(
-          *owner()->parsed_function().expression_temp_var(),
+          owner()->parsed_function().expression_temp_var(),
           constant_false));
       Join(for_test, for_right, for_false);
     } else {
       ASSERT(node->kind() == Token::kOR);
       ValueGraphVisitor for_true(owner(), temp_index());
       Value* constant_true = for_true.Bind(new ConstantVal(bool_true));
       for_true.Do(BuildStoreLocal(
-          *owner()->parsed_function().expression_temp_var(),
+          owner()->parsed_function().expression_temp_var(),
           constant_true));
       Join(for_test, for_true, for_right);
     }
     ReturnComputation(
-        BuildLoadLocal(*owner()->parsed_function().expression_temp_var()));
+        BuildLoadLocal(owner()->parsed_function().expression_temp_var()));
     return;
   }
   EffectGraphVisitor::VisitBinaryOpNode(node);
 }
 
 
 void EffectGraphVisitor::BuildTypecheckArguments(
     intptr_t token_pos,
     Value** instantiator_result,
     Value** instantiator_type_arguments_result) {
   Value* instantiator = NULL;
   Value* instantiator_type_arguments = NULL;
   const Class& instantiator_class = Class::Handle(
       owner()->parsed_function().function().owner());
   // Since called only when type tested against is not instantiated.
   ASSERT(instantiator_class.NumTypeParameters() > 0);
   instantiator = BuildInstantiator();
   if (instantiator == NULL) {
     // No instantiator when inside factory.
     instantiator = BuildNullValue();
     instantiator_type_arguments =
         BuildInstantiatorTypeArguments(token_pos, NULL);
   } else {
     // Preserve instantiator.
-    const LocalVariable& expr_temp =
-        *owner()->parsed_function().expression_temp_var();
+    const LocalVariable* expr_temp =
+        owner()->parsed_function().expression_temp_var();
     instantiator = Bind(BuildStoreLocal(expr_temp, instantiator));
     Value* loaded = Bind(BuildLoadLocal(expr_temp));
     instantiator_type_arguments =
         BuildInstantiatorTypeArguments(token_pos, loaded);
   }
   *instantiator_result = instantiator;
   *instantiator_type_arguments_result = instantiator_type_arguments;
 }
 
 
@@ skipping 273 matching lines @@
 void ValueGraphVisitor::VisitConditionalExprNode(ConditionalExprNode* node) {
   TestGraphVisitor for_test(owner(),
                             temp_index(),
                             node->condition()->token_pos());
   node->condition()->Visit(&for_test);
 
   ValueGraphVisitor for_true(owner(), temp_index());
   node->true_expr()->Visit(&for_true);
   ASSERT(for_true.is_open());
   for_true.Do(BuildStoreLocal(
-      *owner()->parsed_function().expression_temp_var(), for_true.value()));
+      owner()->parsed_function().expression_temp_var(), for_true.value()));
 
   ValueGraphVisitor for_false(owner(), temp_index());
   node->false_expr()->Visit(&for_false);
   ASSERT(for_false.is_open());
   for_false.Do(BuildStoreLocal(
-      *owner()->parsed_function().expression_temp_var(), for_false.value()));
+      owner()->parsed_function().expression_temp_var(), for_false.value()));
 
   Join(for_test, for_true, for_false);
   ReturnComputation(
-      BuildLoadLocal(*owner()->parsed_function().expression_temp_var()));
+      BuildLoadLocal(owner()->parsed_function().expression_temp_var()));
 }
 
 
 // <Statement> ::= If { condition: <Expression>
 //                      true_branch: <Sequence>
 //                      false_branch: <Sequence> }
 void EffectGraphVisitor::VisitIfNode(IfNode* node) {
   TestGraphVisitor for_test(owner(),
                             temp_index(),
                             node->condition()->token_pos());
@@ skipping 494 matching lines @@
   node->closure()->Visit(&for_closure);
   Append(for_closure);
   PushArgumentInstr* push_closure = PushArgument(for_closure.value());
 
   ZoneGrowableArray<PushArgumentInstr*>* arguments =
       new ZoneGrowableArray<PushArgumentInstr*>(node->arguments()->length());
   arguments->Add(push_closure);
   BuildPushArguments(*node->arguments(), arguments);
 
   // Save context around the call.
-  BuildStoreContext(*owner()->parsed_function().expression_temp_var());
+  BuildStoreContext(owner()->parsed_function().expression_temp_var());
   return new ClosureCallComp(node, owner()->try_index(), arguments);
 }
 
 
 void EffectGraphVisitor::VisitClosureCallNode(ClosureCallNode* node) {
   Do(BuildClosureCall(node));
   // Restore context from saved location.
-  BuildLoadContext(*owner()->parsed_function().expression_temp_var());
+  BuildLoadContext(owner()->parsed_function().expression_temp_var());
 }
 
 
 void ValueGraphVisitor::VisitClosureCallNode(ClosureCallNode* node) {
   Value* result = Bind(BuildClosureCall(node));
   // Restore context from temp.
-  BuildLoadContext(*owner()->parsed_function().expression_temp_var());
+  BuildLoadContext(owner()->parsed_function().expression_temp_var());
   ReturnValue(result);
 }
 
 
 void EffectGraphVisitor::VisitCloneContextNode(CloneContextNode* node) {
   Value* context = Bind(new CurrentContextComp());
   Value* clone = Bind(new CloneContextComp(node->token_pos(),
                                            owner()->try_index(),
                                            context));
   ReturnComputation(new StoreContextComp(clone));
@@ skipping 196 matching lines @@
   }
   // The type arguments are uninstantiated. The generated pseudo code:
   //   t1 = InstantiatorTypeArguments();
   //   t2 = ExtractConstructorTypeArguments(t1);
   //   t1 = ExtractConstructorInstantiator(t1);
   //   t_n   <- t2
   //   t_n+1 <- t1
   // Use expression_temp_var and node->allocated_object_var() locals to keep
   // intermediate results around (t1 and t2 above).
   ASSERT(owner()->parsed_function().expression_temp_var() != NULL);
-  const LocalVariable& t1 = *owner()->parsed_function().expression_temp_var();
-  const LocalVariable& t2 = node->allocated_object_var();
+  const LocalVariable* t1 = owner()->parsed_function().expression_temp_var();
+  const LocalVariable* t2 = node->allocated_object_var();
   Value* instantiator_type_arguments = BuildInstantiatorTypeArguments(
       node->token_pos(), NULL);
   ASSERT(instantiator_type_arguments->IsUse());
   Value* stored_instantiator =
       Bind(BuildStoreLocal(t1, instantiator_type_arguments));
   // t1: instantiator type arguments.
 
   Value* extract_type_arguments = Bind(
       new ExtractConstructorTypeArgumentsComp(
           node->token_pos(),
@@ skipping 71 matching lines @@
   Append(for_receiver);
   arguments->Add(PushArgument(for_receiver.value()));
 
   ValueGraphVisitor for_value(owner(), temp_index());
   node->value()->Visit(&for_value);
   Append(for_value);
 
   Value* value = NULL;
   if (result_is_needed) {
     value = Bind(
-        BuildStoreLocal(*owner()->parsed_function().expression_temp_var(),
+        BuildStoreLocal(owner()->parsed_function().expression_temp_var(),
                         for_value.value()));
   } else {
     value = for_value.value();
   }
   arguments->Add(PushArgument(value));
 }
 
 
 void EffectGraphVisitor::VisitInstanceSetterNode(InstanceSetterNode* node) {
   ZoneGrowableArray<PushArgumentInstr*>* arguments =
@@ skipping 10 matching lines @@
 
 void ValueGraphVisitor::VisitInstanceSetterNode(InstanceSetterNode* node) {
   ZoneGrowableArray<PushArgumentInstr*>* arguments =
       new ZoneGrowableArray<PushArgumentInstr*>(2);
   BuildInstanceSetterArguments(node, arguments, true);  // Value used.
   Do(new InstanceSetterComp(node->token_pos(),
                             owner()->try_index(),
                             node->field_name(),
                             arguments));
   ReturnComputation(
-       BuildLoadLocal(*owner()->parsed_function().expression_temp_var()));
+       BuildLoadLocal(owner()->parsed_function().expression_temp_var()));
 }
 
 
 void EffectGraphVisitor::VisitStaticGetterNode(StaticGetterNode* node) {
   const String& getter_name =
       String::Handle(Field::GetterName(node->field_name()));
   const Function& getter_function =
       Function::ZoneHandle(node->cls().LookupStaticFunction(getter_name));
   ASSERT(!getter_function.IsNull());
   ZoneGrowableArray<PushArgumentInstr*>* arguments =
@@ skipping 57 matching lines @@
 // <Expression> ::= StoreLocal { local: LocalVariable
 //                               value: <Expression> }
 void EffectGraphVisitor::VisitStoreLocalNode(StoreLocalNode* node) {
   ValueGraphVisitor for_value(owner(), temp_index());
   node->value()->Visit(&for_value);
   Append(for_value);
   Value* store_value = for_value.value();
   if (FLAG_enable_type_checks) {
     store_value = BuildAssignableValue(node->value()->token_pos(),
                                        store_value,
-                                       node->local().type(),
-                                       node->local().name());
+                                       node->local()->type(),
+                                       node->local()->name());
   }
   Computation* store = BuildStoreLocal(node->local(), store_value);
   ReturnComputation(store);
 }
 
 
 void EffectGraphVisitor::VisitLoadInstanceFieldNode(
     LoadInstanceFieldNode* node) {
   ValueGraphVisitor for_instance(owner(), temp_index());
   node->instance()->Visit(&for_instance);
@@ skipping 102 matching lines @@
                                                  index,
                                                  value);
   ReturnComputation(store);
 }
 
 
 void ValueGraphVisitor::VisitStoreIndexedNode(StoreIndexedNode* node) {
   Value *array, *index, *value;
   BuildStoreIndexedValues(node, &array, &index, &value);
   Value* saved_value = Bind(
-      BuildStoreLocal(*owner()->parsed_function().expression_temp_var(),
+      BuildStoreLocal(owner()->parsed_function().expression_temp_var(),
                       value));
   Do(new StoreIndexedComp(node->token_pos(),
                           owner()->try_index(),
                           array,
                           index,
                           saved_value));
   ReturnComputation(
-       BuildLoadLocal(*owner()->parsed_function().expression_temp_var()));
+       BuildLoadLocal(owner()->parsed_function().expression_temp_var()));
 }
 
 
 bool EffectGraphVisitor::MustSaveRestoreContext(SequenceNode* node) const {
   return (node == owner()->parsed_function().node_sequence()) &&
          (owner()->parsed_function().saved_context_var() != NULL);
 }
 
 
 void EffectGraphVisitor::UnchainContext() {
@@ skipping 22 matching lines @@
         Bind(new AllocateContextComp(node->token_pos(),
                                      owner()->try_index(),
                                      num_context_variables));
 
     // If this node_sequence is the body of the function being compiled, and if
     // this function is not a closure, do not link the current context as the
     // parent of the newly allocated context, as it is not accessible. Instead,
     // save it in a pre-allocated variable and restore it on exit.
     if (MustSaveRestoreContext(node)) {
       Value* current_context = Bind(new CurrentContextComp());
-      Do(BuildStoreLocal(*owner()->parsed_function().saved_context_var(),
+      Do(BuildStoreLocal(owner()->parsed_function().saved_context_var(),
                          current_context));
       Value* null_context = Bind(new ConstantVal(Object::ZoneHandle()));
       Do(new StoreContextComp(null_context));
     }
 
     Do(new ChainContextComp(allocated_context));
     owner()->set_context_level(scope->context_level());
 
     // If this node_sequence is the body of the function being compiled, copy
     // the captured parameters from the frame into the context.
     if (node == owner()->parsed_function().node_sequence()) {
       ASSERT(scope->context_level() == 1);
       const Function& function = owner()->parsed_function().function();
       const int num_params = function.NumberOfParameters();
       int param_frame_index = (num_params == function.num_fixed_parameters()) ?
           (1 + num_params) : ParsedFunction::kFirstLocalSlotIndex;
       for (int pos = 0; pos < num_params; param_frame_index--, pos++) {
-        const LocalVariable& parameter = *scope->VariableAt(pos);
-        ASSERT(parameter.owner() == scope);
-        if (parameter.is_captured()) {
+        const LocalVariable* parameter = scope->VariableAt(pos);
+        ASSERT(parameter->owner() == scope);
+        if (parameter->is_captured()) {
           // Create a temporary local describing the original position.
           const String& temp_name = String::ZoneHandle(String::Concat(
-              parameter.name(), String::Handle(Symbols::New("-orig"))));
+              parameter->name(), String::Handle(Symbols::New("-orig"))));
           LocalVariable* temp_local = new LocalVariable(
               0,  // Token index.
               temp_name,
               Type::ZoneHandle(Type::DynamicType()));  // Type.
           temp_local->set_index(param_frame_index);
 
           // Copy parameter from local frame to current context.
-          Value* load = Bind(BuildLoadLocal(*temp_local));
+          Value* load = Bind(BuildLoadLocal(temp_local));
           Do(BuildStoreLocal(parameter, load));
           // Write NULL to the source location to detect buggy accesses and
           // allow GC of passed value if it gets overwritten by a new value in
           // the function.
           Value* null_constant = Bind(new ConstantVal(Object::ZoneHandle()));
-          Do(BuildStoreLocal(*temp_local, null_constant));
+          Do(BuildStoreLocal(temp_local, null_constant));
         }
       }
     }
   }
 
   if (FLAG_enable_type_checks &&
       (node == owner()->parsed_function().node_sequence())) {
     const Function& function = owner()->parsed_function().function();
     const int num_params = function.NumberOfParameters();
     int pos = 0;
     if (function.IsConstructor()) {
       // Skip type checking of receiver and phase for constructor functions.
       pos = 2;
     } else if (function.IsFactory() || function.IsDynamicFunction()) {
       // Skip type checking of type arguments for factory functions.
       // Skip type checking of receiver for instance functions.
       pos = 1;
     }
     while (pos < num_params) {
-      const LocalVariable& parameter = *scope->VariableAt(pos);
-      ASSERT(parameter.owner() == scope);
-      if (!CanSkipTypeCheck(parameter.token_pos(),
+      const LocalVariable* parameter = scope->VariableAt(pos);
+      ASSERT(parameter->owner() == scope);
+      if (!CanSkipTypeCheck(parameter->token_pos(),
                             NULL,
-                            parameter.type(),
-                            parameter.name())) {
+                            parameter->type(),
+                            parameter->name())) {
         Value* load = Bind(BuildLoadLocal(parameter));
-        Do(BuildAssertAssignable(parameter.token_pos(),
+        Do(BuildAssertAssignable(parameter->token_pos(),
                                  load,
-                                 parameter.type(),
-                                 parameter.name()));
+                                 parameter->type(),
+                                 parameter->name()));
       }
       pos++;
     }
   }
 
   intptr_t i = 0;
   while (is_open() && (i < node->length())) {
     EffectGraphVisitor for_effect(owner(), temp_index());
     node->NodeAt(i++)->Visit(&for_effect);
     Append(for_effect);
     if (!is_open()) {
       // E.g., because of a JumpNode.
       break;
     }
   }
 
   if (is_open()) {
     if (MustSaveRestoreContext(node)) {
       ASSERT(num_context_variables > 0);
-      BuildLoadContext(*owner()->parsed_function().saved_context_var());
+      BuildLoadContext(owner()->parsed_function().saved_context_var());
     } else if (num_context_variables > 0) {
       UnchainContext();
     }
   }
 
   // No continue on sequence allowed.
   ASSERT((node->label() == NULL) ||
          (node->label()->join_for_continue() == NULL));
   // If this node sequence is labeled, a break out of the sequence will have
   // taken care of unchaining the context.
@@ skipping 461 matching lines @@
     for (intptr_t i = 0; i < current->InputCount(); ++i) {
       Value* v = current->InputAt(i);
       if (!v->IsUse()) continue;
       // Update expression stack.
       ASSERT(env->length() > var_count);
       env->RemoveLast();
       BindInstr* as_bind = v->AsUse()->definition()->AsBind();
       if ((as_bind != NULL) && as_bind->computation()->IsLoadLocal()) {
         Computation* comp = as_bind->computation();
         intptr_t index =
-            comp->AsLoadLocal()->local().BitIndexIn(fixed_parameter_count);
+            comp->AsLoadLocal()->local()->BitIndexIn(fixed_parameter_count);
         current->SetInputAt(i, CopyValue((*env)[index]));
       }
       if ((as_bind != NULL) && as_bind->computation()->IsStoreLocal()) {
         // For each use of a StoreLocal: Replace it with the value from the
         // environment.
         Computation* comp = as_bind->computation();
         intptr_t index =
-            comp->AsStoreLocal()->local().BitIndexIn(fixed_parameter_count);
+            comp->AsStoreLocal()->local()->BitIndexIn(fixed_parameter_count);
         current->SetInputAt(i, CopyValue((*env)[index]));
       }
     }
 
     // Drop pushed arguments for calls.
     for (intptr_t j = 0; j < current->ArgumentCount(); j++) {
       env->RemoveLast();
     }
 
     // 2b. Handle LoadLocal and StoreLocal.
     // For each LoadLocal: Remove it from the graph.
     // For each StoreLocal: Remove it from the graph and update the environment.
     BindInstr* bind = current->AsBind();
     if (bind != NULL) {
       LoadLocalComp* load = bind->computation()->AsLoadLocal();
       StoreLocalComp* store = bind->computation()->AsStoreLocal();
       if ((load != NULL) || (store != NULL)) {
         intptr_t index;
         if (store != NULL) {
-          index = store->local().BitIndexIn(fixed_parameter_count);
+          index = store->local()->BitIndexIn(fixed_parameter_count);
           // Update renaming environment.
           (*env)[index] = store->value();
         } else {
           // The graph construction ensures we do not have an unused LoadLocal
           // computation.
           ASSERT(bind->is_used());
-          index = load->local().BitIndexIn(fixed_parameter_count);
+          index = load->local()->BitIndexIn(fixed_parameter_count);
         }
         // Update expression stack and remove from graph.
         if (bind->is_used()) {
           env->Add(CopyValue((*env)[index]));
         }
         it.RemoveCurrentFromGraph();
       } else {
         // Not a load or store.
         if (bind->is_used()) {
           // Assign fresh SSA temporary and update expression stack.
@@ skipping 49 matching lines @@
   char* chars = reinterpret_cast<char*>(
       Isolate::Current()->current_zone()->Allocate(len));
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart