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Chandler CarruthandGeoff Romer
f7e628562f
This is based on an idea suggested during review of the original type erasure PR. The type-erased check failure path lowers each check through `CheckFailFormat<Ts...>`, which builds one format adapter per value, down to the out-of-line `CheckFailImpl`, which takes an array of base-class `format_adapter*` pointers. Previously a separate variadic `CheckFailWithAdapters<Adapters...>` template sat in between: it existed only to bind the adapter temporaries to named parameters so that pointers to their base class could be collected into a `std::array` and outlive the call to `CheckFailImpl`. This removes that layer. `CheckFailFormat` now builds the pointer array directly, in the braced-init-list of the `CheckFailImpl` call, using a small `CheckFailFormatAdapterAddr<T>` helper to take the base-class address of each adapter. The adapter temporaries are materialized as named parameters of that helper within the same full-expression as the `CheckFailImpl` call, so they remain alive across the call without a dedicated function for that purpose. The win is in debug info, not code. `CheckFailWithAdapters<Adapters...>` was instantiated once per distinct adapter-type sequence in every translation unit that uses `CARBON_CHECK`, and each instantiation carried its own DWARF records -- type entries, string-table offsets, and range lists. Dropping it removes those records from every such translation unit. The generated machine code is unchanged. Measured impact (fastbuild, the inputs to the inner-loop links): - First-party object files shrink by 173,728 bytes (-0.233%) across the `carbon-busybox` link inputs; 232 of 270 objects get smaller and none grow. The largest reductions are in the check-densest translation units (`type_completion`, `type`, `import_ref`, `function_context`, `constant`, ...). - Per `bloaty`, the reduction is almost entirely DWARF (`.debug_info`, `.debug_str`, `.rela.debug_str_offsets`, `.debug_rnglists`); the loaded code (VM size) is unchanged. Assisted-by: Claude Code --------- Co-authored-by: Geoff Romer <gromer@google.com>