Add cc_check_undefined (static undefined-symbol check) - #63
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Ports Blade's cc_check_undefined (#1225): for each cc_library, every
undefined external symbol must be resolvable from the library's own
archive, a declared dep's archive, the system libraries a final link
pulls in, or a residual/allow-list regex -- anything left is a missing
dependency. No real link: one `nm -P -g` per archive, set arithmetic,
regex full-match.
New internal/ccundef package:
* nm -P -g external extraction (U undefined; w/v weak-undef ambient; u +
uppercase defined) -- ELF .so gets -D.
* system-symbol baseline: macOS reads the SDK's .tbd stubs
(libc++/libSystem, via xcrun --show-sdk-path -- the dylibs live in the
dyld shared cache, only the text stubs are on disk); Linux resolves
each of libstdc++/c/m/pthread/dl/rt/gcc_s via `cc -print-file-name`
then nm's it. Conservative: an over-broad system set only reduces
findings.
* the residual baseline regexes verbatim from Blade (C++ ABI
typeinfo/vtable/guard, operator new/delete, PIC/TLS bootstrap,
coverage + sanitizer runtimes).
Wiring: build.CheckUndefined runs it as a post-build pass in build/test
(archives must exist); severity from cc_library_config.check_undefined +
check_undefined_severity (default on/warning), plus per-target and global
allow_undefined; --cc-check-undefined / --no-cc-check-undefined force
on/off. gen.LinkArchives exposes a node's own + dep + vcpkg (incl.
protobuf) archives.
Verified on flare (macOS/clang): the whole repo is CLEAN (0 findings),
matching Python Blade. A missing-dep intermediate (packing's protobuf
symbols) surfaced and was fixed by including the protobuf archive in the
link closure -- proving the check isn't vacuous. Unit tests cover the
resolution/baseline/allow logic and severity mapping.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Ports Blade's
cc_check_undefined(#1225). For eachcc_library, every undefined external symbol must resolve to one of: the library's own archive, a declared dep's archive, a system library a final link would pull in, or a residual/allow-list regex. Anything left is a missing dependency — reported without a real link.How
internal/ccundef(new):nm -P -gexternal extraction, a system-symbol baseline (macOS reads the SDK.tbdtext stubs viaxcrun --show-sdk-path; Linux resolves libstdc++/c/m/pthread/dl/rt/gcc_s viacc -print-file-namethennm), and the residual baseline regexes verbatim from Blade (C++ ABI, operator new/delete, PIC/TLS bootstrap, coverage + sanitizer runtimes).build.CheckUndefinedruns as a post-build pass inbuild/test(archives must exist). Severity fromcc_library_config.check_undefined+check_undefined_severity(default on/warning), plus per-target and globalallow_undefined.--cc-check-undefined/--no-cc-check-undefinedforce on/off.gen.LinkArchivesexposes a node's own + dep + vcpkg (incl. protobuf) archives.Verification
On flare (macOS/clang) the whole repo is clean (0 findings), matching Python Blade. An intermediate missing-dep (
packing's protobuf symbols) surfaced and was fixed by including the protobuf archive in the link closure — proving the check isn't vacuous. Unit tests cover resolution/baseline/allow and severity mapping.