Relocate suspended generator activations when enabling debug mode

R=yangguo@chromium.org
BUG=v8:3289
LOG=N

Review URL: https://codereview.chromium.org/260423002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@21141 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/debug.h

@@ -511,6 +511,10 @@ class Debug {
   Handle<Object> CheckBreakPoints(Handle<Object> break_point);
   bool CheckBreakPoint(Handle<Object> break_point_object);
 
+  void MaybeRecompileFunctionForDebugging(Handle<JSFunction> function);
+  void RecompileAndRelocateSuspendedGenerators(
+      const List<Handle<JSGeneratorObject> > &suspended_generators);
+
   // Global handle to debug context where all the debugger JavaScript code is
   // loaded.
   Handle<Context> debug_context_;

src/objects-inl.h

@@ -5711,6 +5711,11 @@ SMI_ACCESSORS(JSGeneratorObject, continuation, kContinuationOffset)
 ACCESSORS(JSGeneratorObject, operand_stack, FixedArray, kOperandStackOffset)
 SMI_ACCESSORS(JSGeneratorObject, stack_handler_index, kStackHandlerIndexOffset)
 
+bool JSGeneratorObject::is_suspended() {
+  ASSERT_LT(kGeneratorExecuting, kGeneratorClosed);
+  ASSERT_EQ(kGeneratorClosed, 0);
+  return continuation() > 0;
+}
 
 JSGeneratorObject* JSGeneratorObject::cast(Object* obj) {
   ASSERT(obj->IsJSGeneratorObject());

src/objects.h

@@ -7461,6 +7461,7 @@ class JSGeneratorObject: public JSObject {
   // cannot be resumed.
   inline int continuation();
   inline void set_continuation(int continuation);
+  inline bool is_suspended();
 
   // [operand_stack]: Saved operand stack.
   DECL_ACCESSORS(operand_stack, FixedArray)

test/mjsunit/harmony/generators-relocation.js

+// Copyright 2014 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.
+
+// Flags: --expose-debug-as debug --harmony-generators
+
+var Debug = debug.Debug;
+
+function assertIteratorResult(value, done, result) {
+  assertEquals({value: value, done: done}, result);
+}
+
+function RunTest(formals_and_body, args, value1, value2) {
+  // A null listener. It isn't important what the listener does.
+  function listener(event, exec_state, event_data, data) {
+  }
+
+  // Create the generator function outside a debugging context. It will probably
+  // be lazily compiled.
+  var gen = (function*(){}).constructor.apply(null, formals_and_body);
+
+  // Instantiate the generator object.
+  var obj = gen.apply(null, args);
+
+  // Advance to the first yield.
+  assertIteratorResult(value1, false, obj.next());
+
+  // Add a breakpoint on line 3 (the second yield).
+  var bp = Debug.setBreakPoint(gen, 3);
+
+  // Enable the debugger, which should force recompilation of the generator
+  // function and relocation of the suspended generator activation.
+  Debug.setListener(listener);
+
+  // Check that the generator resumes and suspends properly.
+  assertIteratorResult(value2, false, obj.next());
+
+  // Disable debugger -- should not force recompilation.
+  Debug.clearBreakPoint(bp);
+  Debug.setListener(null);
+
+  // Run to completion.
+  assertIteratorResult(undefined, true, obj.next());
+}
+
+function prog(a, b, c) {
+  return a + ';\n' + 'yield ' + b + ';\n' + 'yield ' + c;
+}
+
+// Simple empty local scope.
+RunTest([prog('', '1', '2')], [], 1, 2);
+
+RunTest([prog('for (;;) break', '1', '2')], [], 1, 2);
+
+RunTest([prog('while (0) foo()', '1', '2')], [], 1, 2);
+
+RunTest(['a', prog('var x = 3', 'a', 'x')], [1], 1, 3);
+
+RunTest(['a', prog('', '1', '2')], [42], 1, 2);
+
+RunTest(['a', prog('for (;;) break', '1', '2')], [42], 1, 2);