cl compileFunc: cPubName, lookup manglingName

[xushiwei]

No description provided.

[fennoai]

Review: //go:linkname-based function binding generation

This PR wires up NameLookup to skip functions absent from archives, emits //go:linkname directives, adds the cPubName public-name rewriter and forceImportUnsafe, and removes large blocks of legacy commented-out code. The direction is clean and the legacy-code removal is a real readability win. A few robustness and portability items below.

Main themes

• Robustness: nameLookup and two string operations (cPubName's name[0], manglingName[1:]) can panic or misbehave on nil/empty inputs. Inline comments flag the specific spots.
• Portability: the unconditional manglingName[1:] underscore strip assumes the Darwin/Mach-O leading-underscore convention; on Linux/ELF it can drop a real symbol character. See inline.
• Minor / non-blocking:
  • New helpers cPubName, getPubName, forceImportUnsafe (cl/blockctx.go) lack doc comments; cPubName in particular encodes a user-observable naming rule (F, X_g, Xprintf) worth a one-line doc.
  • lib/clang/clang.go receives hand-reflowed doxygen comments. This file looks generated by llcppg's own binding generator (verbatim libclang docs + //go:linkname///llgo:type directives); if so, these cosmetic edits will be overwritten on regeneration and are best reverted.
  • Performance (low, codegen path): fn.Mangling() (a cgo round-trip + string copy) now runs for every function declaration before the nameLookup skip filter, so it's paid even for the many system-header functions that get skipped. If nameLookup could key on the cheaper spelling, Mangling() could be deferred past the filter. m.Dispose() is correctly called on all paths — no leak.

[fennoai]

[P1] nil NameLookup panics compileFunc for callers that omit it

ctx.nameLookup(manglingName) is called unconditionally, but nameLookup is copied verbatim from the exported Config.NameLookup field (compile.go:134), which has no default and is not validated in NewPackage/loadFile. The doc comment (compile.go:83-85) doesn't state the field is required. Any caller constructing a Config without setting NameLookup will hit a nil-function call and panic on the first FunctionDecl. Only the test mock sets it today. Suggest either guarding (if ctx.nameLookup == nil { ... }, treating nil as "always found" or skip), validating in NewPackage with a clear error, or at minimum documenting that NameLookup is mandatory.

[fennoai]

[P1] manglingName[1:] assumes a leading underscore (not portable to ELF)

"C." + manglingName[1:] unconditionally strips the first byte of the mangling name. This is correct only where clang prepends a leading underscore (Darwin/Mach-O, e.g. _g -> mangling __g -> C._g, matching the expected out.go). On Linux/ELF, C symbols typically have no leading underscore, so [1:] drops a real, significant character (e.g. xprintf -> printf), producing an incorrect linkname target. It also silently truncates single-char symbols. Suggest stripping the underscore conditionally (strings.TrimPrefix / check the prefix) or gating on the target object format, and guarding the empty-string case. A short comment explaining the convention would also prevent a future regression.

[fennoai]

[P2] cPubName indexes name[0] with no empty-string guard

cPubName reads name[0] without checking for an empty string; name == "" panics with index-out-of-range. fnName originates from clang.String(fn) on parsed headers, so an anonymous/empty name (or an unexpected clang result) triggers the panic via getPubName. Cheap to guard: if name == "" { return name } at the top. (The ASCII byte-arithmetic uppercasing and the X prefix for leading _ are otherwise correct and match the expected output.)