[generators] Implement %GeneratorGetSourcePosition.

src/interpreter/interpreter.cc

 // Copyright 2015 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/interpreter/interpreter.h"
 
 #include <fstream>
 
 #include "src/ast/prettyprinter.h"
 #include "src/code-factory.h"
@@ skipping 1773 matching lines @@
 }
 
 // Nop
 //
 // No operation.
 void Interpreter::DoNop(InterpreterAssembler* assembler) { __ Dispatch(); }
 
 // SuspendGenerator <generator>
 //
 // Exports the register file and stores it into the generator.  Also stores the
-// current context and the state given in the accumulator into the generator.
+// current context, the state given in the accumulator, and the current bytecode
+// offset (for debugging purposes) into the generator.
 void Interpreter::DoSuspendGenerator(InterpreterAssembler* assembler) {
   Node* generator_reg = __ BytecodeOperandReg(0);
   Node* generator = __ LoadRegister(generator_reg);
 
   Label if_stepping(assembler, Label::kDeferred), ok(assembler);
   Node* step_action_address = __ ExternalConstant(
       ExternalReference::debug_last_step_action_address(isolate_));
   Node* step_action = __ Load(MachineType::Int8(), step_action_address);
   STATIC_ASSERT(StepIn > StepNext);
   STATIC_ASSERT(StepFrame > StepNext);
   STATIC_ASSERT(LastStepAction == StepFrame);
   Node* step_next = __ Int32Constant(StepNext);
   __ BranchIfInt32LessThanOrEqual(step_next, step_action, &if_stepping, &ok);
   __ Bind(&ok);
 
   Node* array =
       __ LoadObjectField(generator, JSGeneratorObject::kOperandStackOffset);
   Node* context = __ GetContext();
   Node* state = __ GetAccumulator();
 
   __ ExportRegisterFile(array);
   __ StoreObjectField(generator, JSGeneratorObject::kContextOffset, context);
   __ StoreObjectField(generator, JSGeneratorObject::kContinuationOffset, state);
 
+  Node* offset = __ SmiTag(__ BytecodeOffset());
+  __ StoreObjectField(generator, JSGeneratorObject::kInputOrDebugPosOffset,
+                      offset);
+
   __ Dispatch();
 
   __ Bind(&if_stepping);
   {
     Node* context = __ GetContext();
     __ CallRuntime(Runtime::kDebugRecordAsyncFunction, context, generator);
     __ Goto(&ok);
   }
 }
 
@@ skipping 15 matching lines @@
   __ StoreObjectField(generator, JSGeneratorObject::kContinuationOffset,
       __ SmiTag(new_state));
   __ SetAccumulator(old_state);
 
   __ Dispatch();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8