nx_cc_equiv_gate.nx

nx_cc_equiv_gate.nx -- COMPILER DIFFERENTIAL-BEHAVIOR ORACLE: miscompile-detection for the sovereign toolchain (EMI-style baseline-vs-challenger build + stdout byte-equal + self-host stage). Team organ (Engineer-owned) born from the dom/licm dormant-paths discovery (ledger T#opt-dom-licm-dormant-paths, 2026-06-10): the deref-cast precedence bug had silently disabled 4 optimizer reads since they were written, and AWAKENING them broke the self-host at generation 3 -- a class of defect no single-binary test catches. This gate judges ANY compiler mutation by BEHAVIOR, not by asm: For each corpus row (deterministic, network-free modules): build with BASELINE cc -> run -> raw wait4 status + stdout bytes build with CHALLENGER cc -> run -> same row PASS iff both build, statuses EQUAL, stdout BYTE-EQUAL. (Different codegen/hoisting is fine; different BEHAVIOR is not.) SELF-HOST stage (the gen3-class catch): challenger compiles runtime/nx_compile_x86.nx -> gen2 binary; gen2 must then compile a probe module whose binary runs exit 0. This is exactly where the awakened-LICM breakage surfaced (gen3: "unknown type name 'nx_size'"). Usage: nx_cc_equiv_gate <challenger_elf> [feature_source.nx] challenger: REQUIRED (a stale default once produced ten confident FAIL rows about a leftover). baseline: _offc/nx_cc_sovereign.elf (the LIVE toolchain) unless knowledge/cc_equiv_baseline.conf names another compiler on its first line. A node names the HUB's promoted compiler there (pulled through nx_content_get, digest-verified) so a candidate that ADDS a language feature can still be judged DIFFERENTIALLY against a baseline that builds the whole corpus (2026-09-15: __size_of on struct types left 5 of 10 rows unbuildable by the live laptop compiler, and "both sides must build" could never pass any capability-adding release -- loosening the rule was the only other exit, and it is the wrong one). ⚠PATHS ARE RESOLVED AFTER THE BUILDROOT ANCHOR: from nxc2/ a relative `_build/x.elf` means buildroot/_build/x.elf. Measured 2026-09-15: a relative challenger path silently named a Sep-4 fossil in buildroot/_build instead of the candidate in nxc2/_build, and the gate printed the caller's path as if it were that binary. Pass an ABSOLUTE path; the gate prints the byte size of every compiler it will exec so the identity is checkable, and refuses a challenger byte-identical to the baseline (a self-comparison measures nothing). Run with CWD=nxc2/ or nishihost/ (it anchors into buildroot/). Exit 0 iff all rows + self-host PASS. Verdicts stream to stdout AND append to the durable log knowledge/status/cc_equiv_gate.log (Archivist rule).