# C/C++ kernel port (R7a) — the bug-for-bug checklist **Status:** survey COMPLETE; grammars VENDORED + suite-green (2026-07-17): tree-sitter-c v0.24.2 (`b780e47`, parser.c `f2883ff9…`) + tree-sitter-cpp v0.23.4 (`f41e1a0`, parser.c `2a35a43b…`, scanner.c `cf60387d…`), built with ts-cli 0.25.10 from checked-in parser.c, in `src/extraction/wasm/` + VENDORED_WASM_LANGS. The walker PR adds the SAME-version crates + kernel grammar registry (kernel-grammar-parity then pins the alignment). Walker + gates not started. This is §0a-recipe step 1's output for c/cpp: every TS-side branch the walker must mirror, with file:line anchors into the reference implementation. Read it WITH `docs/design/rust-kernel-migration-plan.md` (§0a recipe, §5 gates). Companion walkers to crib structure from: `codegraph-kernel/src/tsjs/` (multi- dialect module), `java.rs`, `go.rs` (receiver QNs), `python.rs`. ## Architecture decisions (already made by the plan) 1. **preParse stays TS-side and is HOISTED to the route point.** `tryKernelExtract(filePath, source, lang)` currently receives RAW source (`tree-sitter.ts:6707`); the wasm path applies `extractor.preParse` inside `TreeSitterExtractor` (`tree-sitter.ts:488`). For kernel-routed c/cpp, apply the SAME preParse before the kernel call so both arms parse identical blanked bytes — all seven blanking passes (`preParseCppSource` / `preParseCSource`, `languages/c-cpp.ts:698/750`) then need NO Rust port, and every offset survives (they're all equal-length-space replacements). 2. **Metal + CUDA ride the cpp route** (corrected from the first draft): `.metal`/`.cu` map to language `'cpp'` at detectLanguage (grammars.ts:135), so there is no separate routing decision — when cpp routes to the kernel, those files come along as blanked cpp. The preParse hoist MUST pass `filePath` (the extension gates Metal-attribute blanking) and the CUDA content gate rides for free. Their suite tests are the parity insurance. 3. **One walker module, dual language** (`codegraph-kernel/src/ccpp/`), flagged c vs cpp like `tsjs/` flags its four dialects. Grammars: tree-sitter-c + tree-sitter-cpp crates, wasm vendored from the SAME tags (sha-matched parser.c + scanner, ts-cli 0.25.10). Upgrade the production wasm FIRST and get the full suite green before the walker exists (isolate grammar-bump effects, as R2 did for TS/JS). ## Extractor configs (languages/c-cpp.ts — read the whole file when porting) **cExtractor (line 180):** functionTypes=[function_definition]; NO class/method/interface types; structTypes=[struct_specifier]; enumTypes=[enum_specifier]; enumMemberTypes=[enumerator]; typeAliasTypes=[type_definition]; importTypes=[preproc_include]; callTypes=[call_expression]; variableTypes=[declaration]; nameField=declarator; isConst = any child `type_qualifier` with text `const`; getReturnType = extractCppReturnType; resolveTypeAliasKind = typedef enum/struct with body → that kind (anon inner specifier takes the typedef's name); extractImport: `system_lib_string` → strip `<>`, else `string_literal>string_content`; signature = full `#include` line. recoverMangledName = recoverMangledCppName (post-parse salvage, PORT). **cppExtractor (line 755):** adds classTypes=[class_specifier] with **skipBodilessClass** (forward decls / elaborated refs mint no node, #1093); methodTypes=[function_definition] (method vs function decided by isInsideClassLikeNode); typeAliasTypes += alias_declaration (`using X = …`); resolveName = extractCppQualifiedMethodName (line 75: macro-recovered name first, else LAST `::` segment of the declarator's qualified_identifier — found by BFS that SKIPS parameter_list + trailing_return_type, line 13); getReceiverType = extractCppReceiverType (line 86: the qualifier prefix, `stripCppTemplateArgs`-normalized — multi-line template args must not leak newlines into qualifiedName, #1286/NAME_MAX); getReturnType = extractCppReturnType → normalizeCppReturnType (line 122: smart-ptr/optional unwrap to pointee, cv/template/ptr strip, last `::` segment, primitives → none — set CPP_NON_CLASS_RETURN line 108); getVisibility = nearest preceding `access_specifier` scan in the parent's children (line 785); isMisparsedFunction (line 811): name starts `namespace`, name ∈ {switch,if,for,while,do,case,return}, or isMacroMisparsedTypeDecl (line 261: bodyless class/struct specifier in `type` + non-function_declarator declarator → DROP the node). **Name-salvage helpers to port exactly:** recoverCppMacroDefinedName (line 49 — ALL-CAPS-with-underscore parsed name + first param a LONE lowercase type_identifier + ≥2 params + NO other lone-identifier param; gtest `TEST_F(Fixture, Name)` / `PYBIND11_MODULE(ext, m)` bail); recoverMangledCppName (line 406 — only already-mangled names, `Ret (name)` idiom left alone, last token before `(`, primitive/keyword guard); stripCppTemplateArgs (line 157 — depth-counted removal of every balanced `<…>`); cDeclaratorIdentifier (tree-sitter.ts:234 — declarator chain walk, function_declarator → null, 12-hop guard). ## tree-sitter.ts branches (anchors as of `705e501`) | Line | Mechanism | Must-mirror details | |---|---|---| | 962 | cpp namespace prefix stack (#1291) | named `namespace_definition` pushes its name (C++17 `a::b` as written) onto the QN prefix while walking children; anonymous falls through bare | | 2795 | C file-scope variables | only when NO function ancestor; iterate declarators; accept ONLY init_declarator / pointer_declarator / array_declarator — a BARE identifier declarator is a macro-prototype misparse, skip (loses uninit scalars by design); name via cDeclaratorIdentifier; signature `= `; kind constant/variable via isConst | | 4313 | explicit operator calls (#1247) | callee = `function` field + ERROR-wrapped `operator_name` sibling; compact symbolic spacing (`operator *`→`operator*`, word forms keep space); receiver `->`→`.`; DROP unless receiver is `this` (bare name) or simple identifier/member chain (silent miss over wrong edge) | | ~4340 | field_expression method calls | `recv.method`/`ptr->method` → `recv.method`; SKIP_RECEIVERS {self,this,cls,super} → bare name; LITERAL receiver → emit nothing (#1230) | | 4398 | call-result receivers (#645/#608) | receiver is call_expression → `().` re-encode (c AND cpp in the gate list) | | 4534 | template-arg strip on callees | callee contains `<` and NOT `operator` → stripCppTemplateArgs (CUDA launch sites post-blank take this shape) | | 4545 | local fn-ptr call fan-out (#932-adjacent) | bare-identifier callee found in cppLocalFnPtrs[callerId] → emit one `calls` ref PER recorded target, suppress the local name | | 5173 | stack construction (#1035) | cpp `declaration` where `type` ∈ {type_identifier, template_type, qualified_identifier} and any init_declarator has `value` ∈ {argument_list, initializer_list} → extractInstantiation | | 5183 | fn-ptr binding recording | inside a body: `declaration>init_declarator` (identifier declarator) or `assignment_expression` (identifier left); value must be pointer_expression whose child(0) is `&`; target ∈ {identifier, template_function, qualified_identifier}, template-stripped; per-callerId map of per-local Sets (branch reassignments accumulate) | | 5408 | base_class_clause → extends (#1043) | per base: type_identifier / qualified_identifier / template_type, stripCppTemplateArgs'd; access-specifier keywords skipped | | 4740 | static member refs — **cpp only** (c not in STATIC_MEMBER_LANGS, line 345) | `Foo::BAR` value reads → `references` edge; VERIFY the MEMBER_ACCESS_TYPES shapes for qualified_identifier + the call-callee skip during the port | | — | value-reference edges | **c: YES** (VALUE_REF_LANGS line 401), **cpp: NO**. Port the value-ref machinery for C only (crib go.rs / tsjs — shadow prune, scope stack, MAX_VALUE_REF_NODES cap, CODEGRAPH_VALUE_REFS=0 kill) | | — | fn-ref capture (#756) | function-ref.ts:376: `c: cFamilySpec()`, `cpp: cFamilySpec({ addressOfOnly: true })`; note line ~582: `&Cls::m` exemption from the bare-ids-are-free-functions rule — read cFamilySpec fully when porting | | 355 | INSTANTIATION_KINDS | includes new_expression → cpp `new Foo(...)` instantiates (verify the cpp entry list when porting) | **Generic paths c/cpp share with ported languages** (already mirrored by java.rs/python.rs/go.rs — re-verify each against c/cpp fixtures rather than re-deriving): extractFunction/Method QN via scope stack + receiverType (`Recv::name` like Go), struct/enum/enum_member extraction, typedef → type_alias (+ resolveTypeAliasKind kind override), imports, docstrings (preceding `comment` nodes — docstring.rs already handles C markers incl. the CRLF semantics from #1329), contains edges, signature truncation in UTF-16 units, MAX_FILE_SIZE / generated-file skips, `has_error()` → `defer:`. ## Gates (per plan §5, no exceptions) - Torture fixtures: `torture.c` (fn-ptr tables, typedef enum/struct, file-scope consts incl. multi-declarator, macro-prototype misparse shape, value-refs) + `torture.cpp`/`torture.hpp` (namespaces incl. C++17 nested, out-of-line `Cls::method` defs, templates + template bases, operators incl. spaced call sites, stack construction, local fn-ptrs, UE-macro shapes THROUGH the hoisted preParse, `using` aliases, anonymous namespace, access specifiers). - Parity sweeps + full-init dump-diffs byte-identical: redis + git (C), fmt + a protobuf-class repo (C++), plus a UE-macro-heavy spot-check (blanking-hoist parity) — then linux in cg1212 (expect parse 338s → ~120–180s at the 2c envelope; graph counts must stay 2,048,664/6,405,964). - Deferral-rate guard <10%; suite; changelog rides the existing kernel entry. - DEFAULT_ROUTED += c, cpp only after ALL of the above.