Implement ES6 Template Literals

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 740 matching lines @@
       pre_parse_timer_(NULL) {
   DCHECK(!script().is_null() || info->source_stream() != NULL);
   set_allow_harmony_scoping(!info->is_native() && FLAG_harmony_scoping);
   set_allow_modules(!info->is_native() && FLAG_harmony_modules);
   set_allow_natives_syntax(FLAG_allow_natives_syntax || info->is_native());
   set_allow_lazy(false);  // Must be explicitly enabled.
   set_allow_arrow_functions(FLAG_harmony_arrow_functions);
   set_allow_harmony_numeric_literals(FLAG_harmony_numeric_literals);
   set_allow_classes(FLAG_harmony_classes);
   set_allow_harmony_object_literals(FLAG_harmony_object_literals);
+  set_allow_harmony_templates(FLAG_harmony_templates);
   for (int feature = 0; feature < v8::Isolate::kUseCounterFeatureCount;
        ++feature) {
     use_counts_[feature] = 0;
   }
   if (info->ast_value_factory() == NULL) {
     // info takes ownership of AstValueFactory.
     info->SetAstValueFactory(
         new AstValueFactory(zone(), parse_info->hash_seed));
   }
 }
@@ skipping 4189 matching lines @@
   info()->SetFunction(result);
 
   // We cannot internalize on a background thread; a foreground task will take
   // care of calling Parser::Internalize just before compilation.
 
   if (compile_options() == ScriptCompiler::kProduceParserCache) {
     if (result != NULL) *info_->cached_data() = recorder.GetScriptData();
     log_ = NULL;
   }
 }
+
+
+ParserTraits::TemplateLiteralState Parser::OpenTemplateLiteral(int pos) {
+  return factory()->NewTemplateLiteral(pos);
+}
+
+
+void Parser::AddTemplateSpan(TemplateLiteralState* state) {
+  int pos = scanner()->location().beg_pos;
+  const AstRawString* tv = scanner()->CurrentSymbol(ast_value_factory());
+  const AstRawString* trv = scanner()->CurrentRawSymbol(ast_value_factory());
+  Literal* cooked = factory()->NewStringLiteral(tv, pos);
+  Literal* raw = factory()->NewStringLiteral(trv, pos);
+  (*state)->AddTemplateSpan(cooked, raw, zone());
+}
+
+
+void Parser::AddTemplateExpression(TemplateLiteralState* state,
+                                   Expression* expression) {
+  (*state)->AddExpression(expression, zone());
+}
+
+
+Expression* Parser::CloseTemplateLiteral(TemplateLiteralState* state,
+                                         int start, Expression* tag) {
+#define COOKED_STRING(i) cookedStrings->at(i)
+#define POS(i) cookedStrings->at(i)->position()
+#define EXPR(i) expressions->at(i)
+  TemplateLiteral* lit = *state;
+  int pos = lit->position();
+  const ZoneList<Expression*>* cookedStrings = lit->cooked();
+  const ZoneList<Expression*>* expressions = lit->expressions();
+  CHECK(cookedStrings->length() == (expressions->length() + 1));
+
+  if (!tag) {
+    // Build tree of BinaryOps to simplify code-generation
+    Expression* expr = NULL;
+
+    if (!expressions->length()) {
+      // Simple case: treat as string literal
+      expr = COOKED_STRING(0);
+    } else {
+      int i;
+      expr = factory()->NewBinaryOperation(Token::ADD,
+          COOKED_STRING(0), EXPR(0), POS(0));
+      for (i = 1; i < expressions->length(); ++i) {
+        expr = factory()->NewBinaryOperation(Token::ADD,
+            expr, factory()->NewBinaryOperation(Token::ADD, COOKED_STRING(i),
+            EXPR(i), POS(i)), POS(i));
+      }
+      expr = factory()->NewBinaryOperation(Token::ADD, expr, COOKED_STRING(i),
+          POS(i));
+    }
+    return expr;
+  } else {
+    const ZoneList<Expression*>* rawStrings = lit->raw();
+    int cooked_idx = function_state_->NextMaterializedLiteralIndex();
+    int raw_idx = function_state_->NextMaterializedLiteralIndex();
+

[caitp (gmail), 2014/11/03 20:30:09]

So when it comes to caching the callSiteObj, something that I've tried to do
here is create a new INTERNAL mode variable with scope_->NewInternal(), attach
it to a VariableProxy, and pass the VariableProxy as a third argument to
GetTemplateCallSite() --- and finally, assign the result of
GetTemplateCallSite() to the INTERNAL variable.

I've tried a couple of different approaches, but weirdly I can't seem to get a
real assignment happening, and the internal variable is always undefined.

I think this is the simplest caching mechanism until there's a better way for
this to work, but I might need some pointers on getting it to actually "work".

+    // GetTemplateCallSite
+    ZoneList<Expression*>* args = new (zone()) ZoneList<Expression*>(4, zone());
+    args->Add(factory()->NewArrayLiteral(
+        const_cast<ZoneList<Expression*>*>(cookedStrings), cooked_idx, pos),
+        zone());
+    args->Add(factory()->NewArrayLiteral(
+        const_cast<ZoneList<Expression*>*>(rawStrings), raw_idx, pos), zone());
+    this->CheckPossibleEvalCall(tag, scope_);
+    Expression* expr = factory()->NewCallRuntime(
+        ast_value_factory()->GetTemplateCallSite_string(), NULL, args, start);
+
+    // Call TagFn
+    ZoneList<Expression*>* callArgs = new (zone()) ZoneList<Expression*>(
+        expressions->length() + 1, zone());
+    callArgs->Add(expr, zone());
+    callArgs->AddAll(*expressions, zone());
+    expr = factory()->NewCall(tag, callArgs, pos);
+    if (fni_ != NULL) fni_->RemoveLastFunction();
+    return expr;
+  }
+#undef COOKED_STRING
+#undef POS
+#undef EXPR
+}
+
 } }  // namespace v8::internal