test: verify native GCC mappings and retain ARM64 ELF link evidence

Author: speak-agent

.agents/docs/2026-10-08-llvm-2313-part2-execution-and-dependencies.md

@@ -242,3 +242,26 @@ GCC 16.1.0 对照验证：正常环境编译成功；显式不存在的 GCC_ROOT
 ARM64 消费门切换至 musl GCC 时同一测试变量造成的前端查找污染，
 但 Windows 与 ARM64 的最终通过状态仍须新头执行确认。引擎算法、
 编译器归档及镜像摘要不变，无须重新发布资源。
+
+## 12. 2026-10-08 Windows 回归通过与原生 GNU 单测证据
+
+提交 553861c4 的 [bare Windows job](https://github.com/mcpp-community/mcpp/actions/runs/37701315331/job/113069650755)
+通过首次 fallback、配置持久化、独立 exe 与显式选择验证；同头 Windows
+单测与打包亦通过。该结果验证第 11 节的 GCC_ROOT 根因修复，不能将
+此前失败继续作为基础设施豁免。测试抽象层的四项回归纳入 CI fixture
+门。Ubuntu GCC 13 不处理本次 GCC_ROOT 控制，而生态 GCC 16 处理；
+测试分别保持真实驱动的基线，显式选择生态驱动时要求负控制重现失败。
+
+同头 [原生候选消费门](https://github.com/mcpp-community/mcpp/actions/runs/37701961377)
+已通过 LLVM/GNU 冷安装、头文件隔离、std/std.compat、打包部署、
+GCC-musl 回归及 GNU 自举。完整单测为 145/147：工具链注册测试仍
+将非 x86 Linux 的原生 GCC 映射写成 gcc，现改按实际 musl-gcc
+载荷验证；ELF 测试发现静态 libunwind 的 32 个动态导出符号。
+GNU host helper、四个真实索引成员与 openkal 原生消费尚未执行。
+
+ARM64 与 x86_64 的 libunwind.a 都具有默认可见的全局符号。
+使用同一 ARM64 候选归档交叉链接的异常程序在 QEMU 下运行成功，
+静态归档组合导出零个 unwind 符号；额外链接 libunwind.so 则导出
+31 个并增加对应 DT_NEEDED。这是定位对照，不能替代原生消费证明。
+失败门补存实际测试 ELF、readelf 结果与 build.ninja，再根据链接
+闭包判断原因；尚不调整资产、不隐藏导出以替代动态依赖诊断。

.github/workflows/ci-aarch64-fresh-install.yml

@@ -326,6 +326,23 @@ jobs:
         run: |
           set -euo pipefail
           "$MCPP_NATIVE_GNU" test --toolchain llvm@23.1.3 --target aarch64-linux-gnu 2>&1 | tee "$MCPP_NATIVE_REPORT_DIR/gnu-tests.log"
+      - name: Preserve native ELF and link evidence when the suite fails
+        if: failure()
+        run: |
+          set -euo pipefail
+          evidence="$MCPP_NATIVE_REPORT_DIR/native-link-evidence"
+          mkdir -p "$evidence"
+          while IFS= read -r -d '' binary; do
+            relative="${binary#target/}"
+            mkdir -p "$evidence/$(dirname "$relative")"
+            cp "$binary" "$evidence/$relative"
+            readelf -aW "$binary" > "$evidence/$relative.readelf.txt"
+          done < <(find target/aarch64-linux-gnu -type f -path '*/bin/unit/test_elf_runtime' -print0)
+          while IFS= read -r -d '' plan; do
+            relative="${plan#target/}"
+            mkdir -p "$evidence/$(dirname "$relative")"
+            cp "$plan" "$evidence/$relative"
+          done < <(find target/aarch64-linux-gnu -type f -name build.ninja -print0)
       - name: GNU mcpp builds the LLVM path host helper (804 LLVM case only)
         env:
           MCPP: ${{ env.MCPP_NATIVE_GNU }}

.github/workflows/ci.yml

@@ -143,6 +143,7 @@ jobs:
           python3 tests/scripts/test_check_e2e_coverage.py
           python3 tests/scripts/test_check_default_toolchain_docs.py
           python3 tests/scripts/test_native_candidate_admission.py
+          python3 -m unittest discover -s tests/scripts -p test_toolchain_env.py
 
   build-linux:
     needs: changes

tests/scripts/test_toolchain_env.py

@@ -30,8 +30,13 @@ def test_real_gcc_compiles_after_helper_without_losing_user_prefix(self):
             # missing-cc1plus failure from the isolated Windows fixture.
             bad_env = dict(env, GCC_ROOT=str(root / 'missing-gcc-root'))
             bad = subprocess.run(args, env=bad_env, capture_output=True, text=True)
-            self.assertNotEqual(bad.returncode, 0)
-            self.assertIn('cc1plus', bad.stderr)
+            # Distro GCC 13 can ignore GCC_ROOT; the ecosystem GCC 16
+            # relocation build honors it. Preserve each real driver's
+            # baseline, and require the negative control when that payload
+            # was explicitly selected for this regression.
+            if os.environ.get('MCPP_E2E_GCC_DRIVER'):
+                self.assertNotEqual(bad.returncode, 0)
+                self.assertIn('cc1plus', bad.stderr)
             for context, expected in ((env, 0), (bad_env, bad.returncode)):
                 after = subprocess.run(
                     ['bash', '-c', 'source "$1"; shift; "$@"', 'bash', str(HELPER), *args],

tests/unit/test_toolchain_registry.cpp

@@ -46,10 +46,19 @@ TEST(ToolchainRegistry, MapsGccSpecToGccPackage) {
     // gcc family on a Windows host = MinGW-w64 (the GNU-env host toolchain).
     EXPECT_EQ(pkg.ximName, "mingw-gcc");
 #else
-    EXPECT_EQ(pkg.ximName, "gcc");
-    EXPECT_TRUE(pkg.needsGccPostInstallFixup);
     ASSERT_FALSE(pkg.frontendCandidates.empty());
-    EXPECT_EQ(pkg.frontendCandidates.front(), "g++");
+    if constexpr (mcpp::platform::is_linux
+                  && mcpp::platform::host_arch != std::string_view("x86_64")) {
+        // Non-x86 Linux native GCC payloads are musl-backed even when the host
+        // process uses glibc. Its driver needs no glibc specs fixup.
+        EXPECT_EQ(pkg.ximName, "musl-gcc");
+        EXPECT_FALSE(pkg.needsGccPostInstallFixup);
+        EXPECT_EQ(pkg.frontendCandidates.front(), host_musl() + "-g++");
+    } else {
+        EXPECT_EQ(pkg.ximName, "gcc");
+        EXPECT_TRUE(pkg.needsGccPostInstallFixup);
+        EXPECT_EQ(pkg.frontendCandidates.front(), "g++");
+    }
 #endif
     EXPECT_EQ(pkg.ximVersion, "16.1.0");
     EXPECT_EQ(pkg.display_spec(), "gcc@16.1.0");