experiment with macOS M1 runners

Author: RalfJung

.github/workflows/ci.yml

@@ -24,8 +24,8 @@ jobs:
         include:
           - os: ubuntu-latest
             host_target: x86_64-unknown-linux-gnu
-          - os: macos-latest
-            host_target: x86_64-apple-darwin
+          - os: macos-14
+            host_target: aarch64-apple-darwin
           - os: windows-latest
             host_target: i686-pc-windows-msvc
     runs-on: ${{ matrix.os }}

ci/ci.sh

@@ -128,7 +128,7 @@ case $HOST_TARGET in
   x86_64-unknown-linux-gnu)
     MIRI_TEST_TARGET=i686-unknown-linux-gnu run_tests
     MIRI_TEST_TARGET=aarch64-unknown-linux-gnu run_tests
-    MIRI_TEST_TARGET=aarch64-apple-darwin run_tests
+    MIRI_TEST_TARGET=x86_64-apple-darwin run_tests
     MIRI_TEST_TARGET=i686-pc-windows-gnu run_tests
     # Some targets are only partially supported.
     MIRI_TEST_TARGET=x86_64-unknown-freebsd run_tests_minimal hello integer vec panic/panic concurrency/simple pthread-threadname libc-getentropy libc-getrandom libc-misc libc-fs atomic env align num_cpus
@@ -140,7 +140,7 @@ case $HOST_TARGET in
     MIRI_TEST_TARGET=thumbv7em-none-eabihf run_tests_minimal no_std # no_std embedded architecture
     MIRI_TEST_TARGET=tests/avr.json MIRI_NO_STD=1 run_tests_minimal no_std # JSON target file
     ;;
-  x86_64-apple-darwin)
+  aarch64-apple-darwin)
     MIRI_TEST_TARGET=s390x-unknown-linux-gnu run_tests # big-endian architecture
     MIRI_TEST_TARGET=x86_64-pc-windows-msvc run_tests
     ;;