[ast] Annotate some nodes with number of yields.

src/ast/ast-numbering.cc

 // Copyright 2012 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/ast/ast-numbering.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
 
 namespace v8 {
 namespace internal {
 
 class AstNumberingVisitor final : public AstVisitor {
  public:
   AstNumberingVisitor(Isolate* isolate, Zone* zone)
       : AstVisitor(),
         isolate_(isolate),
         zone_(zone),
         next_id_(BailoutId::FirstUsable().ToInt()),
+        yield_count_(0),
         properties_(zone),
         slot_cache_(zone),
         dont_optimize_reason_(kNoReason) {
     InitializeAstVisitor(isolate);
   }
 
   bool Renumber(FunctionLiteral* node);
 
  private:
 // AST node visitor interface.
 #define DEFINE_VISIT(type) void Visit##type(type* node) override;
   AST_NODE_LIST(DEFINE_VISIT)
 #undef DEFINE_VISIT
 
-  bool Finish(FunctionLiteral* node);
-
   void VisitVariableProxyReference(VariableProxy* node);
   void VisitPropertyReference(Property* node);
   void VisitReference(Expression* expr);
 
   void VisitStatements(ZoneList<Statement*>* statements) override;
   void VisitDeclarations(ZoneList<Declaration*>* declarations) override;
   void VisitArguments(ZoneList<Expression*>* arguments);
   void VisitObjectLiteralProperty(ObjectLiteralProperty* property);
 
   int ReserveIdRange(int n) {
@@ skipping 20 matching lines @@
   }
 
   template <typename Node>
   void ReserveFeedbackSlots(Node* node) {
     node->AssignFeedbackVectorSlots(isolate_, properties_.get_spec(),
                                     &slot_cache_);
   }
 
   BailoutReason dont_optimize_reason() const { return dont_optimize_reason_; }
 
+  int GetAndResetYieldCount() {
+    int old_yield_count = yield_count_;
+    yield_count_ = 0;
+    return old_yield_count;
+  }
+
+  void StoreAndUpdateYieldCount(IterationStatement* node, int old_yield_count) {
+    node->set_yield_count(yield_count_);
+    yield_count_ += old_yield_count;
+  }
+
   Isolate* isolate_;
   Zone* zone_;
   int next_id_;
+  int yield_count_;
   AstProperties properties_;
   // The slot cache allows us to reuse certain feedback vector slots.
   FeedbackVectorSlotCache slot_cache_;
   BailoutReason dont_optimize_reason_;
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
   DISALLOW_COPY_AND_ASSIGN(AstNumberingVisitor);
 };
 
 
@@ skipping 121 matching lines @@
 }
 
 
 void AstNumberingVisitor::VisitReturnStatement(ReturnStatement* node) {
   IncrementNodeCount();
   Visit(node->expression());
 }
 
 
 void AstNumberingVisitor::VisitYield(Yield* node) {
+  yield_count_++;
   IncrementNodeCount();
   DisableOptimization(kYield);
   ReserveFeedbackSlots(node);
   node->set_base_id(ReserveIdRange(Yield::num_ids()));
   Visit(node->generator_object());
   Visit(node->expression());
 }
 
 
 void AstNumberingVisitor::VisitThrow(Throw* node) {
@@ skipping 47 matching lines @@
   node->set_base_id(ReserveIdRange(WithStatement::num_ids()));
   Visit(node->expression());
   Visit(node->statement());
 }
 
 
 void AstNumberingVisitor::VisitDoWhileStatement(DoWhileStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
   node->set_base_id(ReserveIdRange(DoWhileStatement::num_ids()));
+  int old_yield_count = GetAndResetYieldCount();
   Visit(node->body());
   Visit(node->cond());
+  StoreAndUpdateYieldCount(node, old_yield_count);
 }
 
 
 void AstNumberingVisitor::VisitWhileStatement(WhileStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
   node->set_base_id(ReserveIdRange(WhileStatement::num_ids()));
+  int old_yield_count = GetAndResetYieldCount();
   Visit(node->cond());
   Visit(node->body());
+  StoreAndUpdateYieldCount(node, old_yield_count);
 }
 
 
 void AstNumberingVisitor::VisitTryCatchStatement(TryCatchStatement* node) {
   IncrementNodeCount();
   DisableCrankshaft(kTryCatchStatement);
   Visit(node->try_block());
   Visit(node->catch_block());
 }
 
@@ skipping 62 matching lines @@
 
 void AstNumberingVisitor::VisitEmptyParentheses(EmptyParentheses* node) {
   UNREACHABLE();
 }
 
 
 void AstNumberingVisitor::VisitForInStatement(ForInStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
   node->set_base_id(ReserveIdRange(ForInStatement::num_ids()));
+  Visit(node->enumerable());  // Not part of loop.

[neis, 2016/04/13 09:54:27]

Here I'm changing the order of visits, for convenience.  I'm assuming this is
fine.

+  int old_yield_count = GetAndResetYieldCount();
   Visit(node->each());
-  Visit(node->enumerable());
   Visit(node->body());
+  StoreAndUpdateYieldCount(node, old_yield_count);
   ReserveFeedbackSlots(node);
 }
 
 
 void AstNumberingVisitor::VisitForOfStatement(ForOfStatement* node) {
   IncrementNodeCount();
   DisableCrankshaft(kForOfStatement);
   node->set_base_id(ReserveIdRange(ForOfStatement::num_ids()));
-  Visit(node->assign_iterator());
+  Visit(node->assign_iterator());  // Not part of loop.
+  int old_yield_count = GetAndResetYieldCount();
   Visit(node->next_result());
   Visit(node->result_done());
   Visit(node->assign_each());
   Visit(node->body());
+  StoreAndUpdateYieldCount(node, old_yield_count);
   ReserveFeedbackSlots(node);
 }
 
 
 void AstNumberingVisitor::VisitConditional(Conditional* node) {
   IncrementNodeCount();
   node->set_base_id(ReserveIdRange(Conditional::num_ids()));
   Visit(node->condition());
   Visit(node->then_expression());
   Visit(node->else_expression());
@@ skipping 27 matching lines @@
   node->set_base_id(ReserveIdRange(CaseClause::num_ids()));
   if (!node->is_default()) Visit(node->label());
   VisitStatements(node->statements());
 }
 
 
 void AstNumberingVisitor::VisitForStatement(ForStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
   node->set_base_id(ReserveIdRange(ForStatement::num_ids()));
-  if (node->init() != NULL) Visit(node->init());
+  if (node->init() != NULL) Visit(node->init());  // Not part of loop.
+  int old_yield_count = GetAndResetYieldCount();
   if (node->cond() != NULL) Visit(node->cond());
   if (node->next() != NULL) Visit(node->next());
   Visit(node->body());
+  StoreAndUpdateYieldCount(node, old_yield_count);
 }
 
 
 void AstNumberingVisitor::VisitClassLiteral(ClassLiteral* node) {
   IncrementNodeCount();
   DisableCrankshaft(kClassLiteral);
   node->set_base_id(ReserveIdRange(node->num_ids()));
   if (node->extends()) Visit(node->extends());
   if (node->constructor()) Visit(node->constructor());
   if (node->class_variable_proxy()) {
@@ skipping 90 matching lines @@
 
 
 void AstNumberingVisitor::VisitRewritableExpression(
     RewritableExpression* node) {
   IncrementNodeCount();
   node->set_base_id(ReserveIdRange(RewritableExpression::num_ids()));
   Visit(node->expression());
 }
 
 
-bool AstNumberingVisitor::Finish(FunctionLiteral* node) {
-  node->set_ast_properties(&properties_);
-  node->set_dont_optimize_reason(dont_optimize_reason());
-  return !HasStackOverflow();
-}
-
-
 bool AstNumberingVisitor::Renumber(FunctionLiteral* node) {
   Scope* scope = node->scope();
   if (scope->new_target_var()) DisableCrankshaft(kSuperReference);
   if (scope->calls_eval()) DisableOptimization(kFunctionCallsEval);
   if (scope->arguments() != NULL && !scope->arguments()->IsStackAllocated()) {
     DisableCrankshaft(kContextAllocatedArguments);
   }
 
   int rest_index;
   if (scope->rest_parameter(&rest_index)) {
     DisableCrankshaft(kRestParameter);
   }
 
   VisitDeclarations(scope->declarations());
   VisitStatements(node->body());
 
-  return Finish(node);
+  node->set_ast_properties(&properties_);
+  node->set_dont_optimize_reason(dont_optimize_reason());
+  node->set_yield_count(yield_count_);
+  return !HasStackOverflow();
 }
 
 
 bool AstNumbering::Renumber(Isolate* isolate, Zone* zone,
                             FunctionLiteral* function) {
   AstNumberingVisitor visitor(isolate, zone);
   return visitor.Renumber(function);
 }
 }  // namespace internal
 }  // namespace v8