frame_rebase.h

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// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
 
#ifndef RUNTIME_VM_COMPILER_FFI_FRAME_REBASE_H_
#define RUNTIME_VM_COMPILER_FFI_FRAME_REBASE_H_
 
#if defined(DART_PRECOMPILED_RUNTIME)
#error "AOT runtime should not use compiler sources (including header files)"
#endif  // defined(DART_PRECOMPILED_RUNTIME)
 
#include "vm/compiler/backend/locations.h"
#include "vm/compiler/ffi/native_location.h"
#include "vm/compiler/ffi/native_type.h"
#include "vm/compiler/runtime_api.h"
#include "vm/thread.h"
 
namespace dart {
 
namespace compiler {
 
namespace ffi {
 
// Describes a change of stack frame where the stack or base register or stack
// offset may change. This class allows easily rebasing stack locations across
// frame manipulations.
//
// If the stack offset register matches 'old_base', it is changed to 'new_base'
// and 'stack_delta_in_bytes' (# of bytes) is applied.
//
// This class can be used to rebase both Locations and NativeLocations.
class FrameRebase : public ValueObject {
 public:
  FrameRebase(Zone* zone,
              const Register old_base,
              const Register new_base,
              intptr_t stack_delta_in_bytes)
      : zone_(zone),
        old_base_(old_base),
        new_base_(new_base),
        stack_delta_in_bytes_(stack_delta_in_bytes) {}
 
  const NativeLocation& Rebase(const NativeLocation& loc) const;
 
  Location Rebase(const Location loc) const;
 
 private:
  Zone* zone_;
  const Register old_base_;
  const Register new_base_;
  const intptr_t stack_delta_in_bytes_;
};
 
}  // namespace ffi
 
}  // namespace compiler
 
}  // namespace dart
 
#endif  // RUNTIME_VM_COMPILER_FFI_FRAME_REBASE_H_