[ast] Simplify assignment of OSR entry ids.

R=verwaest@chromium.org

Change-Id: I39921052ddf0934f1a626f3e1e458280475ae265
Reviewed-on: https://chromium-review.googlesource.com/539515Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46083}

src/ast/ast-numbering.cc

@@ -50,9 +50,9 @@ class AstNumberingVisitor final : public AstVisitor<AstNumberingVisitor> {
   void VisitArguments(ZoneList<Expression*>* arguments);
   void VisitLiteralProperty(LiteralProperty* property);
 
-  int ReserveIdRange(int n) {
+  int ReserveId() {
     int tmp = next_id_;
-    next_id_ += n;
+    next_id_ += 1;
     return tmp;
   }
 
@@ -335,7 +335,7 @@ void AstNumberingVisitor::VisitWithStatement(WithStatement* node) {
 void AstNumberingVisitor::VisitDoWhileStatement(DoWhileStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
-  node->set_base_id(ReserveIdRange(DoWhileStatement::num_ids()));
+  node->set_osr_id(ReserveId());
   node->set_first_suspend_id(suspend_count_);
   Visit(node->body());
   Visit(node->cond());
@@ -346,7 +346,7 @@ void AstNumberingVisitor::VisitDoWhileStatement(DoWhileStatement* node) {
 void AstNumberingVisitor::VisitWhileStatement(WhileStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
-  node->set_base_id(ReserveIdRange(WhileStatement::num_ids()));
+  node->set_osr_id(ReserveId());
   node->set_first_suspend_id(suspend_count_);
   Visit(node->cond());
   Visit(node->body());
@@ -461,7 +461,7 @@ void AstNumberingVisitor::VisitImportCallExpression(
 void AstNumberingVisitor::VisitForInStatement(ForInStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
-  node->set_base_id(ReserveIdRange(ForInStatement::num_ids()));
+  node->set_osr_id(ReserveId());
   Visit(node->enumerable());  // Not part of loop.
   node->set_first_suspend_id(suspend_count_);
   Visit(node->each());
@@ -474,7 +474,7 @@ void AstNumberingVisitor::VisitForInStatement(ForInStatement* node) {
 void AstNumberingVisitor::VisitForOfStatement(ForOfStatement* node) {
   IncrementNodeCount();
   DisableFullCodegenAndCrankshaft(kForOfStatement);
-  node->set_base_id(ReserveIdRange(ForOfStatement::num_ids()));
+  node->set_osr_id(ReserveId());
   Visit(node->assign_iterator());  // Not part of loop.
   node->set_first_suspend_id(suspend_count_);
   Visit(node->next_result());
@@ -524,7 +524,7 @@ void AstNumberingVisitor::VisitCaseClause(CaseClause* node) {
 void AstNumberingVisitor::VisitForStatement(ForStatement* node) {
   IncrementNodeCount();
   DisableSelfOptimization();
-  node->set_base_id(ReserveIdRange(ForStatement::num_ids()));
+  node->set_osr_id(ReserveId());
   if (node->init() != NULL) Visit(node->init());  // Not part of loop.
   node->set_first_suspend_id(suspend_count_);
   if (node->cond() != NULL) Visit(node->cond());

src/ast/ast.h

@@ -390,7 +390,6 @@ class BreakableStatement : public Statement {
     DCHECK(labels == NULL || labels->length() > 0);
     bit_field_ |= BreakableTypeField::encode(breakable_type);
   }
-  static int parent_num_ids() { return 0; }
 
   static const uint8_t kNextBitFieldIndex = BreakableTypeField::kNext;
 };
@@ -517,9 +516,11 @@ class IterationStatement : public BreakableStatement {
     first_suspend_id_ = first_suspend_id;
   }
 
-  void set_base_id(int id) { base_id_ = id; }
-  static int num_ids() { return parent_num_ids() + 1; }
-  BailoutId OsrEntryId() const { return BailoutId(local_id(0)); }
+  void set_osr_id(int id) { osr_id_ = BailoutId(id); }
+  BailoutId OsrEntryId() const {
+    DCHECK(!osr_id_.IsNone());
+    return osr_id_;
+  }
 
   // Code generation
   Label* continue_target()  { return &continue_target_; }
@@ -528,11 +529,10 @@ class IterationStatement : public BreakableStatement {
   IterationStatement(ZoneList<const AstRawString*>* labels, int pos,
                      NodeType type)
       : BreakableStatement(labels, TARGET_FOR_ANONYMOUS, pos, type),
-        base_id_(BailoutId::None().ToInt()),
+        osr_id_(BailoutId::None()),
         body_(NULL),
         suspend_count_(0),
         first_suspend_id_(0) {}
-  static int parent_num_ids() { return 0; }
   void Initialize(Statement* body, const SourceRange& body_range = {}) {
     body_ = body;
     body_range_ = body_range;
@@ -542,13 +542,7 @@ class IterationStatement : public BreakableStatement {
       BreakableStatement::kNextBitFieldIndex;
 
  private:
-  int local_id(int n) const { return base_id() + parent_num_ids() + n; }
-  int base_id() const {
-    DCHECK(!BailoutId(base_id_).IsNone());
-    return base_id_;
-  }
-
-  int base_id_;
+  BailoutId osr_id_;
   Statement* body_;
   SourceRange body_range_;
   Label continue_target_;