[infra] Add explicit gen_snapshot build target to macOS arm64 AOT builds

macOS arm64 builds only create the x64 gen_snapshot by default because
they are cross-compiled in Rosetta. Adding the gen_snapshot target
ensures that we have a gen_snapshot for arm64 as well.

These bots require clang which currently isn't provisioned on shards, so
they are running on the main bot.

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-mac-release-arm64-try
Change-Id: I842f37019a65dfb30e522d2d9bead5e62bb3ff79
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/204505
Reviewed-by: Siva Annamalai <asiva@google.com>
Reviewed-by: Jonas Termansen <sortie@google.com>

pkg/test_runner/lib/src/compiler_configuration.dart

@@ -844,6 +844,7 @@ class PrecompilerCompilerConfiguration extends CompilerConfiguration
   Command computeAssembleCommand(String tempDir, List arguments,
       Map<String, String> environmentOverrides) {
     String cc, shared, ldFlags;
+    List<String> target;
     if (_isAndroid) {
       cc = "$ndkPath/toolchains/$abiTriple-4.9/prebuilt/"
           "$host-x86_64/bin/$abiTriple-gcc";
@@ -862,6 +863,10 @@ class PrecompilerCompilerConfiguration extends CompilerConfiguration
       shared = '-dynamiclib';
       // Tell Mac linker to give up generating eh_frame from dwarf.
       ldFlags = '-Wl,-no_compact_unwind';
+      if ({Architecture.arm64, Architecture.arm64c}
+          .contains(_configuration.architecture)) {
+        target = ['-arch', 'arm64'];
+      }
     } else {
       throw "Platform not supported: ${Platform.operatingSystem}";
     }
@@ -887,6 +892,7 @@ class PrecompilerCompilerConfiguration extends CompilerConfiguration
     }
 
     var args = [
+      if (target != null) ...target,
       if (ccFlags != null) ccFlags,
       if (ldFlags != null) ldFlags,
       shared,

tools/bots/test_matrix.json

@@ -1318,6 +1318,56 @@
         }
       ]
     },
+    {
+      "builders": [
+        "vm-kernel-precomp-nnbd-mac-release-arm64"
+      ],
+      "meta": {
+        "description": "This configuration is for the macOS arm64 VM AOT nnbd builder group."
+      },
+      "steps": [
+        {
+          "name": "build dart",
+          "script": "tools/build.py",
+          "arguments": [
+            "runtime_kernel",
+            "dart_precompiled_runtime",
+            "gen_snapshot"
+          ]
+        },
+        {
+          "name": "vm nnbd tests in weak mode with asserts",
+          "arguments": [
+            "-ndartkp-weak-asserts-${system}-${mode}-${arch}",
+            "benchmark_smoke",
+            "corelib",
+            "ffi",
+            "language",
+            "lib",
+            "samples",
+            "service",
+            "standalone",
+            "utils",
+            "vm"
+          ]
+        },
+        {
+          "name": "vm nnbd tests in strong mode",
+          "arguments": [
+            "-ndartkp-strong-${system}-${mode}-${arch}",
+            "benchmark_smoke",
+            "corelib",
+            "ffi",
+            "language",
+            "lib",
+            "samples",
+            "standalone",
+            "utils",
+            "vm"
+          ]
+        }
+      ]
+    },
     {
       "builders": [
         "vm-kernel-precomp-nnbd-linux-debug-x64",
@@ -1325,7 +1375,6 @@
         "vm-kernel-precomp-nnbd-linux-release-simarm64c",
         "vm-kernel-precomp-nnbd-linux-release-x64",
         "vm-kernel-precomp-nnbd-linux-release-x64c",
-        "vm-kernel-precomp-nnbd-mac-release-arm64",
         "vm-kernel-precomp-nnbd-mac-release-simarm64",
         "vm-kernel-precomp-nnbd-mac-release-simarm64c",
         "vm-kernel-precomp-nnbd-win-release-x64",