Make Fusion::io_alias_ an AliasInfoMap

[wujingyue]

NFC. Needed by #5229.

This way, I can pass round only the map without the containing fusion.

[wujingyue]

!test

[github-actions]

Review updated until commit a081662

Description

• Replace raw map with AliasInfoMap for better alias management

• Introduce OutputVisibility enum to replace boolean hide_output

• Update alias handling logic across multiple components

• Add helper methods for safer access to alias information

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Changes walkthrough 📝

	Relevant files
Enhancement	fusion.cpp Implement AliasInfoMap and update fusion logic                      csrc/fusion.cpp Replace direct map access with AliasInfoMap methods Use get() and mutable_at() for safer alias access Convert hide_output boolean to OutputVisibility enum Add operator<< for OutputVisibility and AliasInfoMap implementation +61/-26  fusion.h Define OutputVisibility and AliasInfoMap                                  csrc/fusion.h Add OutputVisibility enum Define AliasInfoMap class with proper interface Update AliasInfo to use OutputVisibility instead of bool Change io_alias_ type to AliasInfoMap +34/-5
Bug fix	fusion_executor_cache.cpp Update output visibility check                                                      csrc/runtime/fusion_executor_cache.cpp Update hide_output check to use OutputVisibility Replace boolean comparison with enum comparison +1/-1      validator_utils.cpp Update validation output filtering                                              csrc/validator_utils.cpp Replace hide_output check with OutputVisibility comparison Update lambda to use visibility enum +2/-1      distributed_tensor.cpp Update sharding output filtering                                                  python/python_common/distributed_tensor.cpp Replace hide_output check with OutputVisibility comparison Update conditional to use enum value +2/-1      python_translate.cpp Update Python translation output handling                                python/python_direct/python_translate.cpp Replace hide_output check with OutputVisibility comparison Update conditional logic for output handling +1/-1      translation.cpp Update frontend translation output handling                            python/python_frontend/translation.cpp Replace hide_output check with OutputVisibility comparison Update comment to reflect enum usage +3/-2

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PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🧪 PR contains tests

⚡ Recommended focus areas for review Possible Issue The new add method in AliasInfoMap uses try_emplace and expects insertion to succeed, but the error message uses aliases_.at(out) which may throw if the key is not present, creating a contradiction in error handling. auto [_, inserted] = aliases_.try_emplace( out, AliasInfo{.type = type, .aliased_io = in, .visibility = visibility}); NVF_ERROR( inserted, "The map already has an AliasInfo for ", out, ": ", aliases_.at(out).toString()); } Logic Consistency The get method in AliasInfoMap returns a static no_alias_info for missing entries, but mutable_at directly uses at which throws if the key is not present. This inconsistency could lead to undefined behavior if mutable_at is called on a non-existent key. const AliasInfo& AliasInfoMap::get(const Val* v) const { static AliasInfo no_alias_info{ .type = AllocationType::New, .aliased_io = nullptr, .visibility = OutputVisibility::kVisible}; if (auto search = aliases_.find(v); search != aliases_.end()) { return search->second; } return no_alias_info; }

[wujingyue]

!test

[Priya2698]

This way, I can pass round only the map without the containing fusion.

Even with the existing design, we can pass a map to lowerSegment. The change seems to be that instead of an unordered map, we pass AliasInfoMap. The changes look fine to me, but I don't understand the above motivation completely. I maybe missing something here.

[wujingyue]

Even with the existing design, we can pass a map to lowerSegment.

That's right. Currently, I'm just trying to hide implementation details like https://github.com/NVIDIA/Fuser/pull/5239/files#diff-2aba2455a2f4f8064111d33fb49a7416ffab0f013153f868e5fbaa5309dd5384R144-R151 behind the AliasInfoMap API and other methods of std::unordered_map

[wujingyue]

!test