test: TEMP forensics — static libc++ exit-abort matrix on macos (remove before merge)

Author: Sunrisepeak

.github/workflows/ci-macos.yml

@@ -327,6 +327,29 @@ jobs:
           "$MCPP" self config --mirror GLOBAL
           "$MCPP" test
 
+      - name: "TEMP forensics: static libc++ exit-abort matrix (remove before merge)"
+        if: always()
+        run: |
+          set +e
+          LLVM="$LLVM_ROOT"
+          SDK=$(xcrun --show-sdk-path)
+          cat > /tmp/probe.cpp <<'PEOF'
+          #include <iostream>
+          int main() { std::cout << "hi" << std::endl; return 0; }
+          PEOF
+          run_mode() {
+            echo "=== mode: $1 ==="
+            shift
+            "$LLVM/bin/clang++" --no-default-config -std=c++17 -nostdinc++               -isystem "$LLVM/include/c++/v1" --sysroot="$SDK"               -mmacosx-version-min=11.0 -fuse-ld=lld /tmp/probe.cpp -o /tmp/probe "$@" 2>&1 | head -5
+            otool -L /tmp/probe | grep -E "libc|probe" | head -4
+            /tmp/probe
+            echo "exit=$?"
+          }
+          run_mode dylib    -stdlib=libc++
+          run_mode direct   -nostdlib++ "$LLVM/lib/libc++.a" "$LLVM/lib/libc++abi.a"
+          run_mode hidden   -nostdlib++ -L"$LLVM/lib" -Wl,-hidden-lc++ -Wl,-hidden-lc++abi
+          exit 0
+
       - name: E2E suite
         # See ci-linux.yml — fail-fast on hung tests instead of burning the
         # whole job budget. Per-test 600s timeout lives in run_all.sh.