Add parser support for generators.

src/full-codegen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 214 matching lines @@
   if (prop != NULL || (proxy != NULL && proxy->var()->IsUnallocated())) {
     is_breakable_ = true;
     return;
   }
 
   // Otherwise the assignment is breakable if the assigned value is.
   Visit(expr->value());
 }
 
 
+void BreakableStatementChecker::VisitYield(Yield* expr) {
+  // Yield is breakable if the expression is.
+  Visit(expr->expression());
+}
+
+
 void BreakableStatementChecker::VisitThrow(Throw* expr) {
   // Throw is breakable if the expression is.
   Visit(expr->exception());
 }
 
 
 void BreakableStatementChecker::VisitProperty(Property* expr) {
   // Property load is breakable.
   is_breakable_ = true;
 }
@@ skipping 1285 matching lines @@
 }
 
 
 void FullCodeGenerator::VisitSharedFunctionInfoLiteral(
     SharedFunctionInfoLiteral* expr) {
   Comment cmnt(masm_, "[ SharedFunctionInfoLiteral");
   EmitNewClosure(expr->shared_function_info(), false);
 }
 
 
+void FullCodeGenerator::VisitYield(Yield* expr) {
+  if (expr->is_delegating_yield())
+    UNIMPLEMENTED();
+
+  Comment cmnt(masm_, "[ Yield");
+  VisitForAccumulatorValue(expr->expression());
+  // TODO(wingo): Assert that the operand stack depth is 0, at least while
+  // general yield expressions are unimplemented.
+
+  // TODO(wingo): What follows is as in VisitReturnStatement.  Replace it with a
+  // call to a builtin that will resume the generator.
+  NestedStatement* current = nesting_stack_;
+  int stack_depth = 0;
+  int context_length = 0;
+  while (current != NULL) {
+    current = current->Exit(&stack_depth, &context_length);
+  }
+  __ Drop(stack_depth);
+  EmitReturnSequence();
+}
+
+
 void FullCodeGenerator::VisitThrow(Throw* expr) {
   Comment cmnt(masm_, "[ Throw");
   VisitForStackValue(expr->exception());
   __ CallRuntime(Runtime::kThrow, 1);
   // Never returns here.
 }
 
 
 FullCodeGenerator::NestedStatement* FullCodeGenerator::TryCatch::Exit(
     int* stack_depth,
@@ skipping 25 matching lines @@
   }
 
   return false;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal