More precise break points and stepping when debugging...

src/codegen.cc

Index: src/codegen.cc
===================================================================
--- src/codegen.cc	(revision 4816)
+++ src/codegen.cc	(working copy)
@@ -415,32 +415,41 @@
 }
 
 
-void CodeGenerator::RecordPositions(MacroAssembler* masm, int pos) {
+bool CodeGenerator::RecordPositions(MacroAssembler* masm,
+                                    int pos,
+                                    bool right_here) {
   if (pos != RelocInfo::kNoPosition) {
     masm->RecordStatementPosition(pos);
     masm->RecordPosition(pos);
+    if (right_here) {
+      return masm->WriteRecordedPositions();
+    }
   }
+  return false;
 }
 
 
 void CodeGenerator::CodeForFunctionPosition(FunctionLiteral* fun) {
-  if (FLAG_debug_info) RecordPositions(masm(), fun->start_position());
+  if (FLAG_debug_info) RecordPositions(masm(), fun->start_position(), false);
 }
 
 
 void CodeGenerator::CodeForReturnPosition(FunctionLiteral* fun) {
-  if (FLAG_debug_info) RecordPositions(masm(), fun->end_position());
+  if (FLAG_debug_info) RecordPositions(masm(), fun->end_position(), false);
 }
 
 
 void CodeGenerator::CodeForStatementPosition(Statement* stmt) {
-  if (FLAG_debug_info) RecordPositions(masm(), stmt->statement_pos());
+  if (FLAG_debug_info) RecordPositions(masm(), stmt->statement_pos(), false);
 }
 
+
 void CodeGenerator::CodeForDoWhileConditionPosition(DoWhileStatement* stmt) {
-  if (FLAG_debug_info) RecordPositions(masm(), stmt->condition_position());
+  if (FLAG_debug_info)
+    RecordPositions(masm(), stmt->condition_position(), false);
 }
 
+
 void CodeGenerator::CodeForSourcePosition(int pos) {
   if (FLAG_debug_info && pos != RelocInfo::kNoPosition) {
     masm()->RecordPosition(pos);