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Migrate aig_manager to use smart pointer.

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To decide whether `m_aig_manager` should be a `std::unique_ptr`, `std::shared_ptr`, or `std::weak_ptr`, let's analyze the ownership semantics and usage pattern of `m_aig_manager` in the `aig_tactic` class.

Analysis of Ownership:

1. **Single Ownership**:
   - `m_aig_manager` is allocated within the `mk_aig_manager` struct's constructor, where it calls `alloc(aig_manager, ...)`, and deallocated within the `mk_aig_manager` destructor using `dealloc(m_owner.m_aig_manager);`.
   - `m_aig_manager` is not shared or referenced by any other part of the code outside of `aig_tactic` and `mk_aig_manager`. This suggests that `aig_manager` is owned exclusively by the `aig_tactic` class.

2. **Lifespan Management**:
   - `m_aig_manager` is created within `mk_aig_manager` and is automatically destroyed when `mk_aig_manager` goes out of scope (which happens after the tactic is applied).
   - This indicates that `m_aig_manager`'s lifespan is tightly coupled with the `aig_tactic` class or its method execution.

3. **No Sharing Needed**:
   - There is no indication that `m_aig_manager` needs to be shared across multiple owners or instances. Therefore, there’s no need for `std::shared_ptr`.
   - Since there’s no sharing, `std::weak_ptr` is also unnecessary.

Conclusion:

Given the analysis, **`std::unique_ptr`** is the most appropriate choice for managing `m_aig_manager`. It ensures that the memory is properly managed (automatically deleted when the pointer goes out of scope), and it enforces the exclusive ownership semantics that are currently implied by the code.
This commit is contained in:
Saikat Chakraborty 2024-08-23 18:13:08 +00:00
parent d831ce1161
commit c6032949c8
1 changed files with 4 additions and 7 deletions
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11
src/tactic/aig/aig_tactic.cpp
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@ -27,24 +27,21 @@ class aig_manager;
class aig_tactic : public tactic {
unsigned long long m_max_memory;
bool m_aig_gate_encoding;
aig_manager * m_aig_manager;
std::unique_ptr<aig_manager> m_aig_manager;
struct mk_aig_manager {
aig_tactic & m_owner;
mk_aig_manager(aig_tactic & o, ast_manager & m):m_owner(o) {
aig_manager * mng = alloc(aig_manager, m, o.m_max_memory, o.m_aig_gate_encoding);
m_owner.m_aig_manager = mng;
m_owner.m_aig_manager.reset(mng);
}
~mk_aig_manager() {
dealloc(m_owner.m_aig_manager);
m_owner.m_aig_manager = nullptr;
}
~mk_aig_manager() {}
};
public:
aig_tactic(params_ref const & p = params_ref()):m_aig_manager(nullptr) {
aig_tactic(params_ref const & p = params_ref()) {
updt_params(p);
}