[es6] call ToString() on template substitutions

src/parser.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/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 5460 matching lines @@
   TemplateLiteral* lit = *state;
   int pos = lit->position();
   const ZoneList<Expression*>* cooked_strings = lit->cooked();
   const ZoneList<Expression*>* raw_strings = lit->raw();
   const ZoneList<Expression*>* expressions = lit->expressions();
   DCHECK_EQ(cooked_strings->length(), raw_strings->length());
   DCHECK_EQ(cooked_strings->length(), expressions->length() + 1);
 
   if (!tag) {
     // Build tree of BinaryOps to simplify code-generation
-    Expression* expr = NULL;
+    Expression* expr = cooked_strings->at(0);
+    int i = 0;
+    while (i < expressions->length()) {
+      Expression* sub = expressions->at(i++);
+      Expression* cooked_str = cooked_strings->at(i);
 
-    if (expressions->length() == 0) {
-      // Simple case: treat as string literal
-      expr = cooked_strings->at(0);
-    } else {
-      int i;
-      Expression* cooked_str = cooked_strings->at(0);
+      // Let middle be ToString(sub).
+      ZoneList<Expression*>* args =
+          new (zone()) ZoneList<Expression*>(1, zone());
+      args->Add(sub, zone());
+      Expression* middle = factory()->NewCallRuntime(
+          ast_value_factory()->to_string_string(), NULL, args,
+          sub->position());
+
       expr = factory()->NewBinaryOperation(
-          Token::ADD, cooked_str, expressions->at(0), cooked_str->position());
-      for (i = 1; i < expressions->length(); ++i) {
-        cooked_str = cooked_strings->at(i);
-        expr = factory()->NewBinaryOperation(
-            Token::ADD, expr, factory()->NewBinaryOperation(
-                                  Token::ADD, cooked_str, expressions->at(i),
-                                  cooked_str->position()),
-            cooked_str->position());
-      }
-      cooked_str = cooked_strings->at(i);
-      expr = factory()->NewBinaryOperation(Token::ADD, expr, cooked_str,
-                                           cooked_str->position());
+          Token::ADD, factory()->NewBinaryOperation(
+                          Token::ADD, expr, middle, expr->position()),
+          cooked_str, sub->position());
     }
     return expr;
   } else {
     uint32_t hash = ComputeTemplateLiteralHash(lit);
 
     int cooked_idx = function_state_->NextMaterializedLiteralIndex();
     int raw_idx = function_state_->NextMaterializedLiteralIndex();
 
     // GetTemplateCallSite
     ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(4, zone());
@@ skipping 46 matching lines @@
     } else {
       const uc16* data = reinterpret_cast<const uc16*>(raw_string->raw_data());
       running_hash = StringHasher::ComputeRunningHash(running_hash, data,
                                                       raw_string->length());
     }
   }
 
   return running_hash;
 }
 } }  // namespace v8::internal