Restore GraalVM image support for older CPUs (#4150)

Author: Gedochao

.github/scripts/verify_old_cpus.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+set -e
+
+# Verifies that the native launcher runs on older x86_64 CPUs (without AVX/AVX2/FMA).
+# Uses QEMU user-mode emulation with a Westmere CPU model (2010, SSE4.2 but no AVX).
+
+LAUNCHER_GZ="${1:?Usage: $0 <launcher.gz>}"
+
+sudo apt-get update -qq && sudo apt-get install -y -qq qemu-user > /dev/null
+
+LAUNCHER="/tmp/scala-cli-compat-test"
+gunzip -c "$LAUNCHER_GZ" > "$LAUNCHER"
+chmod +x "$LAUNCHER"
+
+echo "Running native launcher under QEMU with Westmere CPU (no AVX/AVX2/FMA)..."
+qemu-x86_64 -cpu Westmere "$LAUNCHER" version
+echo "CPU compatibility check passed."

.github/workflows/ci.yml

@@ -269,6 +269,8 @@ jobs:
       run: .github/scripts/generate-os-packages.sh
     - name: Copy artifacts
       run: ./mill -i copyDefaultLauncher --directory artifacts/
+    - name: Verify native launcher CPU compatibility
+      run: .github/scripts/verify_old_cpus.sh artifacts/scala-cli-x86_64-pc-linux.gz
     - uses: actions/upload-artifact@v6
       with:
         name: linux-launchers

project/settings/package.mill

@@ -172,6 +172,7 @@ trait CliLaunchers extends SbtModule { self =>
         else staticLibDir().path.toString
       super.nativeImageOptions() ++ Seq(
         "--no-fallback",
+        "-march=compatibility",
         s"-H:IncludeResources=$localRepoResourcePath",
         s"-H:IncludeResources=$launcherTypeResourcePath",
         s"-H:IncludeResources=$defaultFilesResourcePath/.*",