[turbofan] Add support for inlining accessors into try-blocks.

src/compiler/js-native-context-specialization.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-native-context-specialization.h"
 
 #include "src/accessors.h"
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
@@ skipping 727 matching lines @@
 
   // Compute property access infos for the receiver maps.
   AccessInfoFactory access_info_factory(dependencies(), native_context(),
                                         graph()->zone());
   ZoneVector<PropertyAccessInfo> access_infos(zone());
   if (!access_info_factory.ComputePropertyAccessInfos(
           receiver_maps, name, access_mode, &access_infos)) {
     return NoChange();
   }
 
-  // TODO(turbofan): Add support for inlining into try blocks.
-  bool is_exceptional = NodeProperties::IsExceptionalCall(node);
-  for (const auto& access_info : access_infos) {
-    if (access_info.IsAccessorConstant()) {
-      // Accessor in try-blocks are not supported yet.
-      if (is_exceptional || !(flags() & kAccessorInliningEnabled)) {
-        return NoChange();
-      }
-    }
-  }
-
   // Nothing to do if we have no non-deprecated maps.
   if (access_infos.empty()) {
     return ReduceSoftDeoptimize(
         node, DeoptimizeReason::kInsufficientTypeFeedbackForGenericNamedAccess);
   }
 
   // Ensure that {index} matches the specified {name} (if {index} is given).
   if (index != nullptr) {
     Node* check = graph()->NewNode(simplified()->ReferenceEqual(), index,
                                    jsgraph()->HeapConstant(name));
     effect = graph()->NewNode(simplified()->CheckIf(), check, effect, control);
   }
 
+  // Collect call nodes to rewire exception edges.
+  ZoneVector<Node*> if_exception_nodes(zone());
+  ZoneVector<Node*>* if_exceptions = nullptr;
+  Node* if_exception = nullptr;
+  if (NodeProperties::IsExceptionalCall(node, &if_exception)) {
+    if_exceptions = &if_exception_nodes;
+  }
+
   // Check for the monomorphic cases.
   if (access_infos.size() == 1) {
     PropertyAccessInfo access_info = access_infos.front();
     if (HasOnlyStringMaps(access_info.receiver_maps())) {
       // Monormorphic string access (ignoring the fact that there are multiple
       // String maps).
       receiver = effect = graph()->NewNode(simplified()->CheckString(),
                                            receiver, effect, control);
     } else if (HasOnlyNumberMaps(access_info.receiver_maps())) {
       // Monomorphic number access (we also deal with Smis here).
       receiver = effect = graph()->NewNode(simplified()->CheckNumber(),
                                            receiver, effect, control);
     } else {
       // Monomorphic property access.
       receiver = BuildCheckHeapObject(receiver, &effect, control);
       effect = BuildCheckMaps(receiver, effect, control,
                               access_info.receiver_maps());
     }
 
     // Generate the actual property access.
     ValueEffectControl continuation = BuildPropertyAccess(
         receiver, value, context, frame_state, effect, control, name,
-        access_info, access_mode, language_mode);
+        if_exceptions, access_info, access_mode, language_mode);
     value = continuation.value();
     effect = continuation.effect();
     control = continuation.control();
   } else {
     // The final states for every polymorphic branch. We join them with
     // Merge+Phi+EffectPhi at the bottom.
     ZoneVector<Node*> values(zone());
     ZoneVector<Node*> effects(zone());
     ZoneVector<Node*> controls(zone());
 
@@ skipping 82 matching lines @@
               graph()->NewNode(common()->Merge(this_control_count),
                                this_control_count, &this_controls.front());
           this_effects.push_back(this_control);
           this_effect =
               graph()->NewNode(common()->EffectPhi(this_control_count),
                                this_control_count + 1, &this_effects.front());
         }
       }
 
       // Generate the actual property access.
-      ValueEffectControl continuation = BuildPropertyAccess(
-          this_receiver, this_value, context, frame_state, this_effect,
-          this_control, name, access_info, access_mode, language_mode);
+      ValueEffectControl continuation =
+          BuildPropertyAccess(this_receiver, this_value, context, frame_state,
+                              this_effect, this_control, name, if_exceptions,
+                              access_info, access_mode, language_mode);
       values.push_back(continuation.value());
       effects.push_back(continuation.effect());
       controls.push_back(continuation.control());
     }
 
     DCHECK_NULL(fallthrough_control);
 
     // Generate the final merge point for all (polymorphic) branches.
     int const control_count = static_cast<int>(controls.size());
     if (control_count == 0) {
       value = effect = control = jsgraph()->Dead();
     } else if (control_count == 1) {
       value = values.front();
       effect = effects.front();
       control = controls.front();
     } else {
       control = graph()->NewNode(common()->Merge(control_count), control_count,
                                  &controls.front());
       values.push_back(control);
       value = graph()->NewNode(
           common()->Phi(MachineRepresentation::kTagged, control_count),
           control_count + 1, &values.front());
       effects.push_back(control);
       effect = graph()->NewNode(common()->EffectPhi(control_count),
                                 control_count + 1, &effects.front());
     }
   }
+
+  // Properly rewire IfException edges if {node} is inside a try-block.
+  if (!if_exception_nodes.empty()) {
+    DCHECK_NOT_NULL(if_exception);
+    DCHECK_NOT_NULL(if_exceptions);

[Jarin, 2017/05/22 20:23:37]

DCHECK(&if_exception_nodes == if_exceptions);

[Benedikt Meurer, 2017/05/23 11:06:25]

Done.

+    int const if_exception_count = static_cast<int>(if_exceptions->size());
+    Node* merge = graph()->NewNode(common()->Merge(if_exception_count),
+                                   if_exception_count, &if_exceptions->front());
+    if_exceptions->push_back(merge);
+    Node* ephi =
+        graph()->NewNode(common()->EffectPhi(if_exception_count),
+                         if_exception_count + 1, &if_exceptions->front());
+    Node* phi = graph()->NewNode(
+        common()->Phi(MachineRepresentation::kTagged, if_exception_count),
+        if_exception_count + 1, &if_exceptions->front());
+    ReplaceWithValue(if_exception, phi, ephi, merge);
+  }
+
   ReplaceWithValue(node, value, effect, control);
   return Replace(value);
 }
 
 Reduction JSNativeContextSpecialization::ReduceNamedAccessFromNexus(
     Node* node, Node* value, FeedbackNexus const& nexus, Handle<Name> name,
     AccessMode access_mode, LanguageMode language_mode) {
   DCHECK(node->opcode() == IrOpcode::kJSLoadNamed ||
          node->opcode() == IrOpcode::kJSStoreNamed ||
          node->opcode() == IrOpcode::kJSStoreNamedOwn);
@@ skipping 509 matching lines @@
   KeyedAccessStoreMode store_mode = nexus.GetKeyedAccessStoreMode();
 
   // Try to lower the keyed access based on the {nexus}.
   return ReduceKeyedAccess(node, index, value, nexus, AccessMode::kStore,
                            p.language_mode(), store_mode);
 }
 
 JSNativeContextSpecialization::ValueEffectControl
 JSNativeContextSpecialization::BuildPropertyAccess(
     Node* receiver, Node* value, Node* context, Node* frame_state, Node* effect,
-    Node* control, Handle<Name> name, PropertyAccessInfo const& access_info,
-    AccessMode access_mode, LanguageMode language_mode) {
+    Node* control, Handle<Name> name, ZoneVector<Node*>* if_exceptions,
+    PropertyAccessInfo const& access_info, AccessMode access_mode,
+    LanguageMode language_mode) {
   // Determine actual holder and perform prototype chain checks.
   Handle<JSObject> holder;
   if (access_info.holder().ToHandle(&holder)) {
     DCHECK_NE(AccessMode::kStoreInLiteral, access_mode);
     AssumePrototypesStable(access_info.receiver_maps(), holder);
   }
 
   // Generate the actual property access.
   if (access_info.IsNotFound()) {
     DCHECK_EQ(AccessMode::kLoad, access_mode);
     value = jsgraph()->UndefinedConstant();
   } else if (access_info.IsDataConstant()) {
     DCHECK(!FLAG_track_constant_fields);
     Node* constant_value = jsgraph()->Constant(access_info.constant());
     if (access_mode == AccessMode::kStore) {
       Node* check = graph()->NewNode(simplified()->ReferenceEqual(), value,
                                      constant_value);
       effect =
           graph()->NewNode(simplified()->CheckIf(), check, effect, control);
     }
     value = constant_value;
   } else if (access_info.IsAccessorConstant()) {
-    // TODO(bmeurer): Properly rewire the IfException edge here if there's any.
     Node* target = jsgraph()->Constant(access_info.constant());
     FrameStateInfo const& frame_info = OpParameter<FrameStateInfo>(frame_state);
     Handle<SharedFunctionInfo> shared_info =
         frame_info.shared_info().ToHandleChecked();
     switch (access_mode) {
       case AccessMode::kLoad: {
         // We need a FrameState for the getter stub to restore the correct
         // context before returning to fullcodegen.
         FrameStateFunctionInfo const* frame_info0 =
             common()->CreateFrameStateFunctionInfo(FrameStateType::kGetterStub,
@@ skipping 20 matching lines @@
           DCHECK(!function_template_info->call_code()->IsUndefined(isolate()));
           ValueEffectControl value_effect_control = InlineApiCall(
               receiver, context, target, frame_state0, nullptr, effect, control,
               shared_info, function_template_info);
           value = value_effect_control.value();
           effect = value_effect_control.effect();
           control = value_effect_control.control();
         }
         break;
       }
-      case AccessMode::kStoreInLiteral:
       case AccessMode::kStore: {
         // We need a FrameState for the setter stub to restore the correct
         // context and return the appropriate value to fullcodegen.
         FrameStateFunctionInfo const* frame_info0 =
             common()->CreateFrameStateFunctionInfo(FrameStateType::kSetterStub,
                                                    2, 0, shared_info);
         Node* frame_state0 = graph()->NewNode(
             common()->FrameState(BailoutId::None(),
                                  OutputFrameStateCombine::Ignore(),
                                  frame_info0),
@@ skipping 15 matching lines @@
           DCHECK(!function_template_info->call_code()->IsUndefined(isolate()));
           ValueEffectControl value_effect_control = InlineApiCall(
               receiver, context, target, frame_state0, value, effect, control,
               shared_info, function_template_info);
           value = value_effect_control.value();
           effect = value_effect_control.effect();
           control = value_effect_control.control();
         }
         break;
       }
+      case AccessMode::kStoreInLiteral: {
+        UNREACHABLE();
+        break;
+      }
+    }
+    // Remember to rewire the IfException edge if this is inside a try-block.
+    if (if_exceptions != nullptr) {
+      // Create the appropriate IfException/IfSuccess projections.
+      Node* const if_exception =
+          graph()->NewNode(common()->IfException(), control, effect);
+      Node* const if_success = graph()->NewNode(common()->IfSuccess(), control);
+      if_exceptions->push_back(if_exception);
+      control = if_success;
     }
   } else {
     DCHECK(access_info.IsDataField() || access_info.IsDataConstantField());
     FieldIndex const field_index = access_info.field_index();
     Type* const field_type = access_info.field_type();
     MachineRepresentation const field_representation =
         access_info.field_representation();
     if (access_mode == AccessMode::kLoad) {
       if (access_info.holder().ToHandle(&holder)) {
         receiver = jsgraph()->Constant(holder);
@@ skipping 299 matching lines @@
                                  jsgraph()->HeapConstant(cached_name));
   effect = graph()->NewNode(simplified()->CheckIf(), check, effect, control);
 
   Node* value = NodeProperties::GetValueInput(node, 2);
   Node* context = NodeProperties::GetContextInput(node);
   Node* frame_state_lazy = NodeProperties::GetFrameStateInput(node);
 
   // Generate the actual property access.
   ValueEffectControl continuation = BuildPropertyAccess(
       receiver, value, context, frame_state_lazy, effect, control, cached_name,
-      access_info, AccessMode::kStoreInLiteral, LanguageMode::SLOPPY);
+      nullptr, access_info, AccessMode::kStoreInLiteral, LanguageMode::SLOPPY);
   value = continuation.value();
   effect = continuation.effect();
   control = continuation.control();
 
   ReplaceWithValue(node, value, effect, control);
   return Replace(value);
 }
 
 namespace {
 
@@ skipping 683 matching lines @@
   return jsgraph()->javascript();
 }
 
 SimplifiedOperatorBuilder* JSNativeContextSpecialization::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8