[interpreter, debugger] abstraction for source position calculation.

src/debug/debug-frames.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/debug/debug-frames.h"
 
 #include "src/frames-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 51 matching lines @@
       frame_->function()->shared()->asm_function() &&
       !FLAG_turbo_asm_deoptimization) {
     return isolate_->heap()->undefined_value();
   }
   return is_optimized_ ? deoptimized_frame_->GetExpression(index)
                        : frame_->GetExpression(index);
 }
 
 
 int FrameInspector::GetSourcePosition() {
-  return is_optimized_ ? deoptimized_frame_->GetSourcePosition()
-                       : frame_->LookupCode()->SourcePosition(frame_->pc());
+  if (is_optimized_) {
+    return deoptimized_frame_->GetSourcePosition();
+  } else {
+    Code* code = frame_->LookupCode();
+    int offset = static_cast<int>(frame_->pc() - code->instruction_start());
+    return code->SourcePosition(offset);
+  }
 }
 
 
 bool FrameInspector::IsConstructor() {
   return is_optimized_ && !is_bottommost_
              ? deoptimized_frame_->HasConstructStub()
              : frame_->IsConstructor();
 }
 
 
@@ skipping 122 matching lines @@
       if (!frames[i].function()->shared()->IsSubjectToDebugging()) continue;
       if (++count == index) return i;
     }
   }
   return -1;
 }
 
 
 }  // namespace internal
 }  // namespace v8