[interpreter] Switch context during stack unwinding.

src/frames.h

 // Copyright 2012 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.
 
 #ifndef V8_FRAMES_H_
 #define V8_FRAMES_H_
 
 #include "src/allocation.h"
 #include "src/handles.h"
 #include "src/safepoint-table.h"
@@ skipping 172 matching lines @@
       StandardFrameConstants::kFixedFrameSizeFromFp + 2 * kPointerSize;
 
   // FP-relative.
   static const int kBytecodeOffsetFromFp =
       -StandardFrameConstants::kFixedFrameSizeFromFp - 2 * kPointerSize;
   static const int kRegisterFilePointerFromFp =
       -StandardFrameConstants::kFixedFrameSizeFromFp - 3 * kPointerSize;
 
   // Expression index for {StandardFrame::GetExpressionAddress}.
   static const int kBytecodeOffsetExpressionIndex = 1;
+  static const int kRegisterFileExpressionIndex = 2;
 
   // Register file pointer relative.
   static const int kLastParamFromRegisterPointer =
       StandardFrameConstants::kFixedFrameSize + 3 * kPointerSize;
 
   static const int kBytecodeOffsetFromRegisterPointer = 1 * kPointerSize;
   static const int kNewTargetFromRegisterPointer = 2 * kPointerSize;
   static const int kFunctionFromRegisterPointer = 3 * kPointerSize;
   static const int kContextFromRegisterPointer = 4 * kPointerSize;
 };
@@ skipping 522 matching lines @@
   int LookupExceptionHandlerInTable(
       int* stack_slots, HandlerTable::CatchPrediction* prediction) override;
 
   // Returns the current offset into the bytecode stream.
   int GetBytecodeOffset() const;
 
   // Updates the current offset into the bytecode stream, mainly used for stack
   // unwinding to continue execution at a different bytecode offset.
   void PatchBytecodeOffset(int new_offset);
 
+  // Access to the interpreter register file for this frame.
+  Object* GetInterpreterRegister(int register_index) const;
+
   // Build a list with summaries for this frame including all inlined frames.
   void Summarize(List<FrameSummary>* frames) override;
 
  protected:
   inline explicit InterpretedFrame(StackFrameIteratorBase* iterator);
 
  private:
   friend class StackFrameIteratorBase;
 };
 
@@ skipping 242 matching lines @@
 
 
 // Reads all frames on the current stack and copies them into the current
 // zone memory.
 Vector<StackFrame*> CreateStackMap(Isolate* isolate, Zone* zone);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_FRAMES_H_