[turbofan] Use FrameStatesBeforeAndAfter to simplify handling of before/after frame states in AstGr…

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/js-type-feedback.h"
@@ skipping 366 matching lines @@
     control_->LeaveTry(token, value);
     return true;
   }
 
  private:
   DeferredCommands* commands_;
   TryFinallyBuilder* control_;
 };
 
 
+// Helper for generating before and after frame states.
+class AstGraphBuilder::FrameStateBeforeAndAfter {
+ public:
+  FrameStateBeforeAndAfter(AstGraphBuilder* builder, BailoutId id_before)
+      : builder_(builder), frame_state_before_(nullptr) {
+    ResetBefore(id_before);
+  }
+
+  void ResetBefore(BailoutId id_before) {
+    frame_state_before_ = id_before == BailoutId::None()
+                              ? builder_->jsgraph()->EmptyFrameState()
+                              : builder_->environment()->Checkpoint(id_before);
+  }
+
+  void AddToNode(Node* node, BailoutId id_after,
+                 OutputFrameStateCombine combine) {
+    int count = OperatorProperties::GetFrameStateInputCount(node->op());
+    DCHECK_LE(count, 2);
+
+    if (count >= 1) {
+      // Add the frame state for after the operation.
+      DCHECK_EQ(IrOpcode::kDead,
+                NodeProperties::GetFrameStateInput(node, 0)->opcode());
+
+      Node* frame_state_after =
+          id_after == BailoutId::None()
+              ? builder_->jsgraph()->EmptyFrameState()
+              : builder_->environment()->Checkpoint(id_after, combine);
+
+      NodeProperties::ReplaceFrameStateInput(node, 0, frame_state_after);
+    }
+
+    if (count >= 2) {
+      // Add the frame state for before the operation.
+      DCHECK_EQ(IrOpcode::kDead,
+                NodeProperties::GetFrameStateInput(node, 1)->opcode());
+      NodeProperties::ReplaceFrameStateInput(node, 1, frame_state_before_);
+    }
+  }
+
+ private:
+  AstGraphBuilder* builder_;
+  Node* frame_state_before_;
+};
+
+
 AstGraphBuilder::AstGraphBuilder(Zone* local_zone, CompilationInfo* info,
                                  JSGraph* jsgraph, LoopAssignmentAnalysis* loop,
                                  JSTypeFeedbackTable* js_type_feedback)
     : local_zone_(local_zone),
       info_(info),
       jsgraph_(jsgraph),
       environment_(nullptr),
       ast_context_(nullptr),
       globals_(0, local_zone),
       execution_control_(nullptr),
@@ skipping 900 matching lines @@
         javascript()->CallFunction(3, NO_CALL_FUNCTION_FLAGS, language_mode()),
         function, obj, value);
     PrepareFrameState(res, stmt->FilterId(), OutputFrameStateCombine::Push());
     Node* property_missing =
         NewNode(javascript()->StrictEqual(), res, jsgraph()->ZeroConstant());
     {
       IfBuilder is_property_missing(this);
       is_property_missing.If(property_missing);
       is_property_missing.Then();
       // Inc counter and continue.
-      Node* index_inc =
-          NewNode(javascript()->Add(LanguageMode::SLOPPY), index,
-                  jsgraph()->OneConstant());
-      // TODO(jarin): provide real bailout id.
-      PrepareFrameStateAfterAndBefore(index_inc, BailoutId::None(),
-                                      OutputFrameStateCombine::Ignore(),
-                                      jsgraph()->EmptyFrameState());
-      environment()->Poke(0, index_inc);
+      {
+        // TODO(jarin): provide real bailout id.
+        FrameStateBeforeAndAfter states(this, BailoutId::None());
+        Node* index_inc = NewNode(javascript()->Add(LanguageMode::SLOPPY),
+                                  index, jsgraph()->OneConstant());
+        states.AddToNode(index_inc, BailoutId::None(),
+                         OutputFrameStateCombine::Ignore());
+        environment()->Poke(0, index_inc);
+      }
       for_loop.Continue();
       is_property_missing.Else();
       is_property_missing.End();
     }
     // Replace 'value' in environment.
     environment()->Push(res);
     test_should_filter.Else();
     test_should_filter.End();
   }
   value = environment()->Pop();
   // Bind value and do loop body.
   VisitForInAssignment(stmt->each(), value, stmt->AssignmentId());
   VisitIterationBody(stmt, &for_loop);
   index = environment()->Peek(0);
   for_loop.EndBody();
 
   // Inc counter and continue.
   Node* index_inc =
       NewNode(javascript()->Add(LanguageMode::SLOPPY), index,
               jsgraph()->OneConstant());
-  // TODO(jarin): provide real bailout id.
-  PrepareFrameStateAfterAndBefore(index_inc, BailoutId::None(),
-                                  OutputFrameStateCombine::Ignore(),
-                                  jsgraph()->EmptyFrameState());
+  {
+    // TODO(jarin): provide real bailout ids.
+    FrameStateBeforeAndAfter states(this, BailoutId::None());
+    states.AddToNode(index_inc, BailoutId::None(),
+                     OutputFrameStateCombine::Ignore());
+  }
   environment()->Poke(0, index_inc);
   for_loop.EndLoop();
   environment()->Drop(5);
   // PrepareForBailoutForId(stmt->ExitId(), NO_REGISTERS);
 }
 
 
 void AstGraphBuilder::VisitForOfStatement(ForOfStatement* stmt) {
   LoopBuilder for_loop(this);
   VisitForEffect(stmt->assign_iterator());
@@ skipping 514 matching lines @@
   environment()->Push(literal);
   environment()->Push(literal_index);
 
   // Create nodes to evaluate all the non-constant subexpressions and to store
   // them into the newly cloned array.
   for (int i = 0; i < expr->values()->length(); i++) {
     Expression* subexpr = expr->values()->at(i);
     if (CompileTimeValue::IsCompileTimeValue(subexpr)) continue;
 
     VisitForValue(subexpr);
-    Node* frame_state_before = environment()->Checkpoint(
-        subexpr->id(), OutputFrameStateCombine::PokeAt(0));
-    Node* value = environment()->Pop();
-    Node* index = jsgraph()->Constant(i);
-    Node* store =
-        BuildKeyedStore(literal, index, value, TypeFeedbackId::None());
-    PrepareFrameStateAfterAndBefore(store, expr->GetIdForElement(i),
-                                    OutputFrameStateCombine::Ignore(),
-                                    frame_state_before);
+    {
+      FrameStateBeforeAndAfter states(this, subexpr->id());
+      Node* value = environment()->Pop();
+      Node* index = jsgraph()->Constant(i);
+      Node* store =
+          BuildKeyedStore(literal, index, value, TypeFeedbackId::None());
+      states.AddToNode(store, expr->GetIdForElement(i),
+                       OutputFrameStateCombine::Ignore());
+    }
   }
 
   environment()->Pop();  // Array literal index.
   ast_context()->ProduceValue(environment()->Pop());
 }
 
 
 void AstGraphBuilder::VisitForInAssignment(Expression* expr, Node* value,
                                            BailoutId bailout_id) {
   DCHECK(expr->IsValidReferenceExpression());
@@ skipping 17 matching lines @@
       Handle<Name> name = property->key()->AsLiteral()->AsPropertyName();
       Node* store =
           BuildNamedStore(object, name, value, TypeFeedbackId::None());
       PrepareFrameState(store, bailout_id);
       break;
     }
     case KEYED_PROPERTY: {
       environment()->Push(value);
       VisitForValue(property->obj());
       VisitForValue(property->key());
-      Node* key = environment()->Pop();
-      Node* object = environment()->Pop();
-      value = environment()->Pop();
-      Node* store = BuildKeyedStore(object, key, value, TypeFeedbackId::None());
-      // TODO(jarin) Provide a real frame state before.
-      PrepareFrameStateAfterAndBefore(store, bailout_id,
-                                      OutputFrameStateCombine::Ignore(),
-                                      jsgraph()->EmptyFrameState());
+      {
+        // TODO(jarin) Provide a real frame state before.
+        FrameStateBeforeAndAfter states(this, BailoutId::None());
+        Node* key = environment()->Pop();
+        Node* object = environment()->Pop();
+        value = environment()->Pop();
+        Node* store =
+            BuildKeyedStore(object, key, value, TypeFeedbackId::None());
+        states.AddToNode(store, bailout_id, OutputFrameStateCombine::Ignore());
+      }
       break;
     }
   }
 }
 
 
 void AstGraphBuilder::VisitAssignment(Assignment* expr) {
   DCHECK(expr->target()->IsValidReferenceExpression());
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->target()->AsProperty();
   LhsKind assign_type = DetermineLhsKind(expr->target());
+  bool needs_frame_state_before = true;
 
   // Evaluate LHS expression.
   switch (assign_type) {
-    case VARIABLE:
-      // Nothing to do here.
+    case VARIABLE: {
+      Variable* variable = expr->target()->AsVariableProxy()->var();
+      if (variable->location() == Variable::PARAMETER ||
+          variable->location() == Variable::LOCAL ||
+          variable->location() == Variable::CONTEXT) {
+        needs_frame_state_before = false;
+      }
       break;
+    }
     case NAMED_PROPERTY:
       VisitForValue(property->obj());
       break;
     case KEYED_PROPERTY: {
       VisitForValue(property->obj());
       VisitForValue(property->key());
       break;
     }
   }
 
+  FrameStateBeforeAndAfter store_states(this, BailoutId::None());
   // Evaluate the value and potentially handle compound assignments by loading
   // the left-hand side value and performing a binary operation.
-  Node* frame_state_before_store = nullptr;
-  bool needs_frame_state_before = (assign_type == KEYED_PROPERTY);
   if (expr->is_compound()) {
     Node* old_value = NULL;
     switch (assign_type) {
       case VARIABLE: {
         VariableProxy* proxy = expr->target()->AsVariableProxy();
         VectorSlotPair pair =
             CreateVectorSlotPair(proxy->VariableFeedbackSlot());
         old_value = BuildVariableLoad(proxy->var(), expr->target()->id(), pair);
         break;
       }
@@ skipping 15 matching lines @@
             CreateVectorSlotPair(property->PropertyFeedbackSlot());
         old_value =
             BuildKeyedLoad(object, key, pair, property->PropertyFeedbackId());
         PrepareFrameState(old_value, property->LoadId(),
                           OutputFrameStateCombine::Push());
         break;
       }
     }
     environment()->Push(old_value);
     VisitForValue(expr->value());
-    Node* frame_state_before = environment()->Checkpoint(expr->value()->id());
-    Node* right = environment()->Pop();
-    Node* left = environment()->Pop();
-    Node* value = BuildBinaryOp(left, right, expr->binary_op());
-    PrepareFrameStateAfterAndBefore(value, expr->binary_operation()->id(),
-                                    OutputFrameStateCombine::Push(),
-                                    frame_state_before);
+    Node* value;
+    {
+      FrameStateBeforeAndAfter states(this, expr->value()->id());
+      Node* right = environment()->Pop();
+      Node* left = environment()->Pop();
+      value = BuildBinaryOp(left, right, expr->binary_op());
+      states.AddToNode(value, expr->binary_operation()->id(),
+                       OutputFrameStateCombine::Push());
+    }
     environment()->Push(value);
     if (needs_frame_state_before) {
-      frame_state_before_store = environment()->Checkpoint(
-          expr->binary_operation()->id(), OutputFrameStateCombine::PokeAt(0));
+      store_states.ResetBefore(expr->binary_operation()->id());

[Jarin, 2015/05/12 08:15:33]

Can't we make the ResetBefore method private and just record the bailout id
here? (And instantiate store_states after the if statement with the recorded
bailout id.)

     }
   } else {
     VisitForValue(expr->value());
     if (needs_frame_state_before) {
       // This frame state can be used for lazy-deopting from a to-number
       // conversion if we are storing into a typed array. It is important
       // that the frame state is usable for such lazy deopt (i.e., it has
       // to specify how to override the value before the conversion, in this
       // case, it overwrites the stack top).
-      frame_state_before_store = environment()->Checkpoint(
-          expr->value()->id(), OutputFrameStateCombine::PokeAt(0));
+      store_states.ResetBefore(expr->value()->id());
     }
   }
 
   // Store the value.
   Node* value = environment()->Pop();
   switch (assign_type) {
     case VARIABLE: {
       Variable* variable = expr->target()->AsVariableProxy()->var();
       BuildVariableAssignment(variable, value, expr->op(), expr->id(),
                               ast_context()->GetStateCombine());
       break;
     }
     case NAMED_PROPERTY: {
       Node* object = environment()->Pop();
       Handle<Name> name = property->key()->AsLiteral()->AsPropertyName();
       Node* store =
           BuildNamedStore(object, name, value, expr->AssignmentFeedbackId());
-      PrepareFrameState(store, expr->id(), ast_context()->GetStateCombine());
+      store_states.AddToNode(store, expr->id(),
+                             ast_context()->GetStateCombine());
       break;
     }
     case KEYED_PROPERTY: {
       Node* key = environment()->Pop();
       Node* object = environment()->Pop();
       Node* store =
           BuildKeyedStore(object, key, value, expr->AssignmentFeedbackId());
-      PrepareFrameStateAfterAndBefore(store, expr->id(),
-                                      ast_context()->GetStateCombine(),
-                                      frame_state_before_store);
+      store_states.AddToNode(store, expr->id(),
+                             ast_context()->GetStateCombine());
       break;
     }
   }
 
   ast_context()->ProduceValue(value);
 }
 
 
 void AstGraphBuilder::VisitYield(Yield* expr) {
   // TODO(turbofan): Implement yield here.
@@ skipping 301 matching lines @@
       stack_depth = 2;
       break;
     }
   }
 
   // Convert old value into a number.
   old_value = NewNode(javascript()->ToNumber(), old_value);
   PrepareFrameState(old_value, expr->ToNumberId(),
                     OutputFrameStateCombine::Push());
 
-  Node* frame_state_before_store =
-      assign_type == KEYED_PROPERTY
-          ? environment()->Checkpoint(expr->ToNumberId())
-          : nullptr;
+  // TODO(titzer): combine this framestate with the above?
+  FrameStateBeforeAndAfter store_states(this, assign_type == KEYED_PROPERTY
+                                                  ? expr->ToNumberId()
+                                                  : BailoutId::None());
 
   // Save result for postfix expressions at correct stack depth.
   if (is_postfix) environment()->Poke(stack_depth, old_value);
 
   // Create node to perform +1/-1 operation.
-  Node* value =
-      BuildBinaryOp(old_value, jsgraph()->OneConstant(), expr->binary_op());
-  // This should never deoptimize because we have converted to number
-  // before.
-  PrepareFrameStateAfterAndBefore(value, BailoutId::None(),
-                                  OutputFrameStateCombine::Ignore(),
-                                  jsgraph()->EmptyFrameState());
+  Node* value;
+  {
+    FrameStateBeforeAndAfter states(this, BailoutId::None());
+    value =
+        BuildBinaryOp(old_value, jsgraph()->OneConstant(), expr->binary_op());
+    // This should never deoptimize because we have converted to number
+    // before.
+    states.AddToNode(value, BailoutId::None(),
+                     OutputFrameStateCombine::Ignore());
+  }
 
   // Store the value.
   switch (assign_type) {
     case VARIABLE: {
       Variable* variable = expr->expression()->AsVariableProxy()->var();
       environment()->Push(value);
       BuildVariableAssignment(variable, value, expr->op(),
                               expr->AssignmentId());
       environment()->Pop();
       break;
     }
     case NAMED_PROPERTY: {
       Node* object = environment()->Pop();
       Handle<Name> name = property->key()->AsLiteral()->AsPropertyName();
       Node* store =
           BuildNamedStore(object, name, value, expr->CountStoreFeedbackId());
       environment()->Push(value);
       PrepareFrameState(store, expr->AssignmentId());
       environment()->Pop();
       break;
     }
     case KEYED_PROPERTY: {
       Node* key = environment()->Pop();
       Node* object = environment()->Pop();
       Node* store =
           BuildKeyedStore(object, key, value, expr->CountStoreFeedbackId());
       environment()->Push(value);
-      PrepareFrameStateAfterAndBefore(store, expr->AssignmentId(),
-                                      OutputFrameStateCombine::Ignore(),
-                                      frame_state_before_store);
+      store_states.AddToNode(store, expr->AssignmentId(),
+                             OutputFrameStateCombine::Ignore());
       environment()->Pop();
       break;
     }
   }
 
   // Restore old value for postfix expressions.
   if (is_postfix) value = environment()->Pop();
 
   ast_context()->ProduceValue(value);
 }
 
 
 void AstGraphBuilder::VisitBinaryOperation(BinaryOperation* expr) {
   switch (expr->op()) {
     case Token::COMMA:
       return VisitComma(expr);
     case Token::OR:
     case Token::AND:
       return VisitLogicalExpression(expr);
     default: {
       VisitForValue(expr->left());
       VisitForValue(expr->right());
-      Node* frame_state_before = environment()->Checkpoint(expr->right()->id());
+      FrameStateBeforeAndAfter states(this, expr->right()->id());
       Node* right = environment()->Pop();
       Node* left = environment()->Pop();
       Node* value = BuildBinaryOp(left, right, expr->op());
-      PrepareFrameStateAfterAndBefore(value, expr->id(),
-                                      ast_context()->GetStateCombine(),
-                                      frame_state_before);
+      states.AddToNode(value, expr->id(), ast_context()->GetStateCombine());
       ast_context()->ProduceValue(value);
     }
   }
 }
 
 
 void AstGraphBuilder::VisitCompareOperation(CompareOperation* expr) {
   const Operator* op;
   switch (expr->op()) {
     case Token::EQ:
@@ skipping 842 matching lines @@
     DCHECK_EQ(1, OperatorProperties::GetFrameStateInputCount(node->op()));
 
     DCHECK_EQ(IrOpcode::kDead,
               NodeProperties::GetFrameStateInput(node, 0)->opcode());
     NodeProperties::ReplaceFrameStateInput(
         node, 0, environment()->Checkpoint(ast_id, combine));
   }
 }
 
 
-void AstGraphBuilder::PrepareFrameStateAfterAndBefore(
-    Node* node, BailoutId ast_id, OutputFrameStateCombine combine,
-    Node* frame_state_before) {
-  if (OperatorProperties::GetFrameStateInputCount(node->op()) > 0) {
-    DCHECK_EQ(2, OperatorProperties::GetFrameStateInputCount(node->op()));
-
-    DCHECK_EQ(IrOpcode::kDead,
-              NodeProperties::GetFrameStateInput(node, 0)->opcode());
-    NodeProperties::ReplaceFrameStateInput(
-        node, 0, environment()->Checkpoint(ast_id, combine));
-
-    DCHECK_EQ(IrOpcode::kDead,
-              NodeProperties::GetFrameStateInput(node, 1)->opcode());
-    NodeProperties::ReplaceFrameStateInput(node, 1, frame_state_before);
-  }
-}
-
-
 BitVector* AstGraphBuilder::GetVariablesAssignedInLoop(
     IterationStatement* stmt) {
   if (loop_assignment_analysis_ == NULL) return NULL;
   return loop_assignment_analysis_->GetVariablesAssignedInLoop(stmt);
 }
 
 
 Node** AstGraphBuilder::EnsureInputBufferSize(int size) {
   if (size > input_buffer_size_) {
     size = size + kInputBufferSizeIncrement + input_buffer_size_;
@@ skipping 277 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8