[es6] Fix tail Call nodes marking.

TBR=rossberg@chromium.org

Review URL: https://codereview.chromium.org/1666183002

Cr-Commit-Position: refs/heads/master@{#33761}

src/ast/ast.h

@@ -473,7 +473,10 @@ class Block final : public BreakableStatement {
   }
 
   void MarkTail() override {
-    if (!statements_.is_empty()) statements_.last()->MarkTail();
+    for (int i = 0; i < statements_.length(); i++) {
+      Statement* stmt = statements_.at(i);
+      stmt->MarkTail();
+    }
   }
 
   Scope* scope() const { return scope_; }
@@ -962,7 +965,6 @@ class ExpressionStatement final : public Statement {
   void set_expression(Expression* e) { expression_ = e; }
   Expression* expression() const { return expression_; }
   bool IsJump() const override { return expression_->IsThrow(); }
-  void MarkTail() override { expression_->MarkTail(); }
 
  protected:
   ExpressionStatement(Zone* zone, Expression* expression, int pos)
@@ -1020,6 +1022,8 @@ class ReturnStatement final : public JumpStatement {
 
   void set_expression(Expression* e) { expression_ = e; }
 
+  void MarkTail() override { expression_->MarkTail(); }
+
  protected:
   explicit ReturnStatement(Zone* zone, Expression* expression, int pos)
       : JumpStatement(zone, pos), expression_(expression) { }
@@ -1089,7 +1093,10 @@ class CaseClause final : public Expression {
   TypeFeedbackId CompareId() { return TypeFeedbackId(local_id(1)); }
 
   void MarkTail() override {
-    if (!statements_->is_empty()) statements_->last()->MarkTail();
+    for (int i = 0; i < statements_->length(); i++) {
+      Statement* stmt = statements_->at(i);
+      stmt->MarkTail();
+    }
   }
 
   Type* compare_type() { return compare_type_; }
@@ -1125,7 +1132,10 @@ class SwitchStatement final : public BreakableStatement {
   void set_tag(Expression* t) { tag_ = t; }
 
   void MarkTail() override {
-    if (!cases_->is_empty()) cases_->last()->MarkTail();
+    for (int i = 0; i < cases_->length(); i++) {
+      CaseClause* clause = cases_->at(i);
+      clause->MarkTail();
+    }
   }
 
  protected:

src/ast/prettyprinter.cc

@@ -1608,7 +1608,9 @@ void AstPrinter::VisitProperty(Property* node) {
 
 void AstPrinter::VisitCall(Call* node) {
   EmbeddedVector<char, 128> buf;
-  FormatSlotNode(&buf, node, "CALL", node->CallFeedbackICSlot());
+  const char* name =
+      node->tail_call_mode() == TailCallMode::kAllow ? "TAIL CALL" : "CALL";
+  FormatSlotNode(&buf, node, name, node->CallFeedbackICSlot());
   IndentedScope indent(this, buf.start());
 
   Visit(node->expression());

src/parsing/parser.cc

@@ -2792,11 +2792,6 @@ Statement* Parser::ParseReturnStatement(bool* ok) {
           is_undefined, ThisExpression(scope_, factory(), pos),
           is_object_conditional, pos);
     }
-
-    // ES6 14.6.1 Static Semantics: IsInTailPosition
-    if (FLAG_harmony_tailcalls && !is_sloppy(language_mode())) {
-      return_value->MarkTail();
-    }
   }
   ExpectSemicolon(CHECK_OK);
 
@@ -4750,6 +4745,13 @@ ZoneList<Statement*>* Parser::ParseEagerFunctionBody(
                     RelocInfo::kNoPosition));
   }
 
+  // ES6 14.6.1 Static Semantics: IsInTailPosition
+  if (FLAG_harmony_tailcalls && !is_sloppy(language_mode())) {
+    for (int i = 0; i < body->length(); i++) {
+      Statement* stmt = body->at(i);
+      stmt->MarkTail();
+    }
+  }
   return result;
 }