[debugger] fix break locations for assignments and return.

src/interpreter/bytecode-generator.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/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-register-allocator.h"
 #include "src/interpreter/control-flow-builders.h"
@@ skipping 555 matching lines @@
 
 Handle<BytecodeArray> BytecodeGenerator::MakeBytecode(CompilationInfo* info) {
   set_info(info);
   set_scope(info->scope());
 
   // Initialize bytecode array builder.
   set_builder(new (zone()) BytecodeArrayBuilder(
       isolate(), zone(), info->num_parameters_including_this(),
       scope()->MaxNestedContextChainLength(), scope()->num_stack_slots()));
 
+  builder()->InitializeReturnPosition(info->literal());
+
   // Initialize the incoming context.
   ContextScope incoming_context(this, scope(), false);
 
   // Initialize control scope.
   ControlScopeForTopLevel control(this);
 
   // Build function context only if there are context allocated variables.
   if (scope()->NeedsContext()) {
     // Push a new inner context scope for the function.
     VisitNewLocalFunctionContext();
@@ skipping 284 matching lines @@
   execution_control()->Continue(stmt->target());
 }
 
 
 void BytecodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
   execution_control()->Break(stmt->target());
 }
 
 
 void BytecodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
+  builder()->SetStatementPosition(stmt);

[vogelheim, 2016/02/29 17:43:30]

Just for my understanding: These switched lines is what sets the first
breakpoint, at (before) the return value evaluation?

[Yang, 2016/02/29 17:53:12]

Yes, correct.

   VisitForAccumulatorValue(stmt->expression());
-  builder()->SetStatementPosition(stmt);
   execution_control()->ReturnAccumulator();
 }
 
 
 void BytecodeGenerator::VisitWithStatement(WithStatement* stmt) {
   VisitForAccumulatorValue(stmt->expression());
   builder()->CastAccumulatorToJSObject();
   VisitNewLocalWithContext();
   VisitInScope(stmt->statement(), stmt->scope());
 }
@@ skipping 2245 matching lines @@
 }
 
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return info()->feedback_vector()->GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8