[ci] Add support for building on aarch64-darwin

This will fail for now. But allows us to add aarch64-darwin
machines to CI.

(cherry picked from commit a7d22795ed118abfe64f4fc55d96d8561007ce1e)

2 files changed, 77 insertions, 21 deletions

diff --git a/.gitlab/ci.sh b/.gitlab/ci.sh
index 66c52a7c94..db75cc1fef 100755
--- a/.gitlab/ci.sh
+++ b/.gitlab/ci.sh
@@ -3,9 +3,7 @@
 
 # This is the primary driver of the GitLab CI infrastructure.
 # Run `ci.sh usage` for usage information.
-
-
-set -e -o pipefail
+set -Eeuo pipefail
 
 # Configuration:
 HACKAGE_INDEX_STATE="2020-12-21T14:48:20Z" # TODO dedup with yaml's def
@@ -173,12 +171,18 @@ function show_tool() {
 
 function set_toolchain_paths() {
   needs_toolchain="1"
-  case "$(uname)" in
-    Linux) needs_toolchain="0" ;;
+  case "$(uname -m)-$(uname)" in
+    *-Linux) needs_toolchain="" ;;
     *) ;;
   esac
 
-  if [[ "$needs_toolchain" = "1" ]]; then
+  if [[ -n "${IN_NIX_SHELL:-}" ]]; then
+      needs_toolchain=""
+      GHC="$(which ghc)"
+      CABAL="$(which cabal)"
+      HAPPY="$(which happy)"
+      ALEX="$(which alex)"
+  elif [[ -n "$needs_toolchain" ]]; then
       # These are populated by setup_toolchain
       GHC="$toolchain/bin/ghc$exe"
       CABAL="$toolchain/bin/cabal$exe"
@@ -354,7 +358,7 @@ BUILD_SPHINX_HTML=$BUILD_SPHINX_HTML
 BUILD_SPHINX_PDF=$BUILD_SPHINX_PDF
 BeConservative=YES
 BIGNUM_BACKEND=$BIGNUM_BACKEND
-XZ_CMD=$XZ
+XZ_CMD=${XZ:-}
 
 BuildFlavour=$BUILD_FLAVOUR
 ifneq "\$(BuildFlavour)" ""
@@ -363,7 +367,7 @@ endif
 GhcLibHcOpts+=-haddock
 EOF
 
-  if [ -n "$HADDOCK_HYPERLINKED_SOURCES" ]; then
+  if [ -n "${HADDOCK_HYPERLINKED_SOURCES:-}" ]; then
     echo "EXTRA_HADDOCK_OPTS += --hyperlinked-source --quickjump" >> mk/build.mk
   fi
 
@@ -382,7 +386,7 @@ function configure() {
   end_section "booting"
 
   local target_args=""
-  if [[ -n "$target_triple" ]]; then
+  if [[ -n "${target_triple:-}" ]]; then
     target_args="--target=$target_triple"
   fi
 
@@ -403,7 +407,7 @@ function build_make() {
   if [[ -z "$BIN_DIST_PREP_TAR_COMP" ]]; then
     fail "BIN_DIST_PREP_TAR_COMP is not set"
   fi
-  if [[ -n "$VERBOSE" ]]; then
+  if [[ -n "${VERBOSE:-}" ]]; then
     MAKE_ARGS="$MAKE_ARGS V=1"
   else
     MAKE_ARGS="$MAKE_ARGS V=0"
@@ -422,7 +426,7 @@ function fetch_perf_notes() {
 }
 
 function push_perf_notes() {
-  if [ -n "$CROSS_TARGET" ]; then
+  if [ -n "${CROSS_TARGET:-}" ]; then
     info "Can't test cross-compiled build."
     return
   fi
@@ -439,16 +443,16 @@ function determine_metric_baseline() {
 }
 
 function test_make() {
-  if [ -n "$CROSS_TARGET" ]; then
+  if [ -n "${CROSS_TARGET:-}" ]; then
     info "Can't test cross-compiled build."
     return
   fi
 
   run "$MAKE" test_bindist TEST_PREP=YES
-  run "$MAKE" V=0 test \
+  run "$MAKE" V=0 VERBOSE=1 test \
     THREADS="$cores" \
     JUNIT_FILE=../../junit.xml \
-    EXTRA_RUNTEST_OPTS="$RUNTEST_ARGS"
+    EXTRA_RUNTEST_OPTS="${RUNTEST_ARGS:-}"
 }
 
 function build_hadrian() {
@@ -462,7 +466,7 @@ function build_hadrian() {
 }
 
 function test_hadrian() {
-  if [ -n "$CROSS_TARGET" ]; then
+  if [ -n "${CROSS_TARGET:-}" ]; then
     info "Can't test cross-compiled build."
     return
   fi
@@ -476,7 +480,7 @@ function test_hadrian() {
     test \
     --summary-junit=./junit.xml \
     --test-compiler="$TOP"/_build/install/bin/ghc \
-    "runtest.opts+=$RUNTEST_ARGS"
+    "runtest.opts+=${RUNTEST_ARGS:-}"
 }
 
 function cabal_test() {
@@ -517,14 +521,14 @@ function run_hadrian() {
   if [ -z "$BUILD_FLAVOUR" ]; then
     fail "BUILD_FLAVOUR not set"
   fi
-  if [ -z "$BIGNUM_BACKEND" ]; then BIGNUM_BACKEND="gmp"; fi
-  if [ -n "$VERBOSE" ]; then HADRIAN_ARGS="$HADRIAN_ARGS -V"; fi
+  if [ -z "${BIGNUM_BACKEND:-}" ]; then BIGNUM_BACKEND="gmp"; fi
+  if [ -n "${VERBOSE:-}" ]; then HADRIAN_ARGS="${HADRIAN_ARGS:-} -V"; fi
   run hadrian/build-cabal \
     --flavour="$BUILD_FLAVOUR" \
     -j"$cores" \
-    --broken-test="$BROKEN_TESTS" \
+    --broken-test="${BROKEN_TESTS:-}" \
     --bignum=$BIGNUM_BACKEND \
-    $HADRIAN_ARGS \
+    ${HADRIAN_ARGS:-} \
     $@
 }
 
@@ -560,7 +564,7 @@ case "$(uname)" in
   *) fail "uname $(uname) is not supported" ;;
 esac
 
-if [ -n "$CROSS_TARGET" ]; then
+if [ -n "${CROSS_TARGET:-}" ]; then
   info "Cross-compiling for $CROSS_TARGET..."
   target_triple="$CROSS_TARGET"
 fi
diff --git a/.gitlab/shell.nix b/.gitlab/shell.nix
new file mode 100644
index 0000000000..f5c691ffaa
--- /dev/null
+++ b/.gitlab/shell.nix
@@ -0,0 +1,52 @@
+{ system ? "aarch64-darwin"
+#, nixpkgs ? fetchTarball https://github.com/angerman/nixpkgs/archive/257cb120334.tar.gz #apple-silicon.tar.gz
+, pkgs ? import <nixpkgs> { inherit system; }
+, compiler ? if system == "aarch64-darwin" then "ghc8103Binary" else "ghc8103"
+}: pkgs.mkShell {
+  # this prevents nix from trying to write the env-vars file.
+  # we can't really, as NIX_BUILD_TOP/env-vars is not set.
+  noDumpEnvVars=1;
+
+  # we need to inject ncurses into --with-curses-libraries.
+  # the real fix is to teach terminfo to use libcurses on macOS.
+  CONFIGURE_ARGS = "--with-intree-gmp --with-curses-libraries=${pkgs.ncurses.out}/lib";
+
+  buildInputs = with pkgs; [
+    haskell.compiler.${compiler}
+    haskell.packages.${compiler}.cabal-install
+    haskell.packages.${compiler}.alex
+    haskell.packages.${compiler}.happy # _1_19_12 is needed for older GHCs.
+
+    clang_11
+    llvm_11
+
+    automake
+    autoconf
+    m4
+
+    gmp
+    ncurses
+    libiconv
+    zlib.out
+    zlib.dev
+    glibcLocales
+    # locale doesn't build yet :-/
+    # locale
+
+    git
+
+    python3
+    # python3Full
+    # python3Packages.sphinx
+    perl
+
+    which
+    wget
+    file
+
+    xz
+    xlibs.lndir
+
+    cacert
+  ];
+}