Adds LintContext::Tokens() and friends, backed by clang_tokenize, as the
substrate the rules will move onto. Nothing consumes it yet.
libclang is dlopen'd rather than linked: -lclang would break the mingw and
MSVC cross-builds at link time and would put a libclang.so.NN runtime
dependency into the otherwise self-contained release tarballs. The clang-c
header is used for its declarations only, and the function-pointer table is
typed with decltype so the signatures cannot drift from the real API.
Three properties this buys that the hand-rolled scanners could not have:
- a raw string literal or block comment is ONE token, so the documented
"raw string literals are not recognized" limitation goes away;
- `//` inside a literal is not a comment, so LineHasComment() replaces the
Line(n).contains("//") probes that false-positive on it;
- tokens cover preprocessor branches that are inactive for the host, since
clang_tokenize lexes rather than evaluates #if. Token rules therefore
keep seeing every platform's code, which an AST could not offer.
The parse backing the tokenizer is expected to fail on module units — no
PCMs, no build flags — and that is fine, because lexing has no semantic
prerequisites. Verified in the new tests.
LintSummary::Clean() now counts `errors`. It previously ignored them, so an
infrastructure failure that produced no findings reported clean and exited
0; a missing libclang would have been exactly that.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
