runtime/vm/compiler/ffi/frame_rebase.h

// 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_