| // 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_API_DEOPT_ID_H_ |
| #define RUNTIME_VM_COMPILER_API_DEOPT_ID_H_ |
| |
| #include "platform/allocation.h" |
| |
| namespace dart { |
| |
| // Deoptimization Id logic. |
| // |
| // Deoptimization ids are used to refer to deoptimization points, at which |
| // control can enter unoptimized code from the optimized version of the code. |
| // |
| // Note: any instruction that does a call has two deoptimization points, |
| // one before the call and one after the call - so that we could deoptimize |
| // to either before or after the call depending on whether the same call |
| // already occurred in the optimized code (and potentially produced |
| // observable side-effects) or not. |
| // |
| // To simplify implementation we always allocate two deopt ids (one for before |
| // point and one for the after point). |
| class DeoptId : public AllStatic { |
| public: |
| static constexpr intptr_t kNone = -1; |
| |
| static inline intptr_t Next(intptr_t deopt_id) { return deopt_id + kStep; } |
| |
| static inline intptr_t ToDeoptAfter(intptr_t deopt_id) { |
| ASSERT(IsDeoptBefore(deopt_id)); |
| return deopt_id + kAfterOffset; |
| } |
| |
| static inline bool IsDeoptBefore(intptr_t deopt_id) { |
| return (deopt_id % kStep) == kBeforeOffset; |
| } |
| |
| static inline bool IsDeoptAfter(intptr_t deopt_id) { |
| return (deopt_id % kStep) == kAfterOffset; |
| } |
| |
| private: |
| static constexpr intptr_t kStep = 2; |
| static constexpr intptr_t kBeforeOffset = 0; |
| static constexpr intptr_t kAfterOffset = 1; |
| }; |
| |
| } // namespace dart |
| |
| #endif // RUNTIME_VM_COMPILER_API_DEOPT_ID_H_ |