DROPME Add a CI workflow to test cross compilers

This CI workflow is not intended to be merged on the main branch as is.
Its purpose is to help review the cross compiler.

If it is deemed interesting to keep it for special cases (to run the
test from time to time, rather less regularly), it could be triggered on
explicit `workflow_dispatch` or on a specific label. In that case, it
might make sense to amend it, in particular the tests for the new cases
in `sak` could be dropped.

.gitattributes

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 /.github/**              typo.missing-header typo.long-line=may typo.very-long-line=may
+/.github/workflows/build-cross.yml typo.non-ascii
 
 /.mailmap                typo.long-line typo.missing-header typo.non-ascii
 /CONTRIBUTING.md         typo.non-ascii=may

.github/workflows/build-cross.yml

@@ -0,0 +1,301 @@
+name: Cross compilers
+
+on:
+  push:
+    branches:
+      - '4.**'
+      - '5.**'
+      - 'trunk'
+  pull_request:
+
+# Restrict the GITHUB_TOKEN
+permissions: {}
+
+# See build.yml
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name == 'pull_request' || github.sha }}
+  cancel-in-progress: true
+
+env:
+  TESTDIR: >-
+    C:\Бактріан🐫
+  STR_UTF8: >-
+    "C:\\Бактріан🐫"
+  STR_UTF16: >-
+    L"C:\\\x0411\x0430\x043a\x0442\x0440\x0456\x0430\x043d\xd83d\xdc2b"
+  STR_UTF8_ENC: >-
+    "C:\\\xd0\x91\xd0\xb0\xd0\xba\xd1\x82\xd1\x80\xd1\x96\xd0\xb0\xd0\xbd\xf0\x9f\x90\xab"
+  EXAMPLE_PROGRAM: |
+    let _ =
+      Printf.printf "Version: %s\nOS: %s\nUnix: %b\nWin: %b\nCygwin: %b\n"
+        Sys.ocaml_version Sys.os_type Sys.unix Sys.win32 Sys.cygwin
+  COMPLIBS_PROG_X86_64: |
+    let _ =
+      Printf.printf "allow_unaligned_access = %b\n" Arch.allow_unaligned_access;
+      Printf.printf "win64 = %b\n" Arch.win64
+  COMPLIBS_PROG_AARCH64: |
+    let _ =
+      Printf.printf "allow_unaligned_access = %b\n" Arch.allow_unaligned_access;
+      Printf.printf "macosx = %b\n" Arch.macosx
+
+jobs:
+  non-cross:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout OCaml
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Configure, build and install OCaml
+        run: |
+          PREFIX="$HOME/.local"
+          echo "$PREFIX/bin" >> "$GITHUB_PATH"
+          set -x
+          if ! ./configure --disable-warn-error --disable-ocamldoc \
+                   --disable-ocamltest --disable-stdlib-manpages \
+                   --disable-dependency-generation --prefix="$PREFIX" ; then
+            cat config.log
+            exit 1
+          fi
+          make -j
+          make install
+          cd "$HOME"
+          tar caf /tmp/ocaml.tar.zst .local
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: non-cross-ocaml
+          path: /tmp/ocaml.tar.zst
+          retention-days: 1
+
+  cross-windows:
+    runs-on: ubuntu-latest
+    needs: non-cross
+    steps:
+      - name: Download Artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: non-cross-ocaml
+      - name: Install non-cross OCaml and set up environment
+        run: |
+          set -x
+          tar xaf ocaml.tar.zst -C "$HOME"
+          rm -f ocaml.tar.zst
+          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+          sudo apt-get install -y gcc-mingw-w64-x86-64
+      - name: Checkout OCaml
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+          persist-credentials: false
+      - name: Configure, build and install Linux-to-Windows OCaml
+        run: |
+          set -x
+          if ! ./configure --prefix="$HOME/cross" --target=x86_64-w64-mingw32 \
+                   --with-target-libdir="$TESTDIR"; then
+            cat config.log
+            exit 1
+          fi
+          make crossopt -j$(nproc)
+          make installcross
+          ln -sr "$HOME/cross/bin/flexlink.opt.exe" "$HOME/.local/bin/flexlink"
+      - name: Show opt.opt configuration
+        run: |
+          $HOME/cross/bin/ocamlopt.opt.exe -config
+      - name: Cross compile a small program
+        run: |
+          printf %s "$EXAMPLE_PROGRAM$COMPLIBS_PROG_X86_64" > example.ml
+          set -x
+          cat example.ml
+          $HOME/cross/bin/ocamlopt.opt.exe -I $HOME/cross/lib/ocaml/compiler-libs/ ocamlcommon.cmxa ocamloptcomp.cmxa example.ml -o example.exe -verbose
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: windows-executable
+          path: example.exe
+          retention-days: 1
+      - name: Test cross sak
+        run: |
+          printf %s "$STR_UTF16" > utf16.ref
+          printf %s "$STR_UTF8" > utf8.ref
+          set -x
+          runtime/sak.exe encode-C-utf16-literal "$TESTDIR" > utf16
+          git diff --no-index utf16.ref utf16
+          runtime/sak.exe encode-C-utf8-literal "$TESTDIR" > utf8
+          git diff --no-index utf8.ref utf8
+
+  run-windows:
+    runs-on: windows-latest
+    needs: cross-windows
+    steps:
+      - name: Download Artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: windows-executable
+      - name: Run example program
+        run: |
+          .\example.exe
+      - name: Set up MSVC
+        uses: ilammy/msvc-dev-cmd@v1
+        with:
+          arch: x64
+      - name: Fetch OCaml
+        uses: actions/checkout@v4
+      - name: Generate a dummy misc.h and result files to test sak
+        shell: bash
+        run: |
+          echo '#include <stdlib.h>' > runtime/caml/misc.h
+          echo 'typedef wchar_t char_os;' >> runtime/caml/misc.h
+          echo '#define T(x) L ## x' >> runtime/caml/misc.h
+          echo '#define main_os wmain' >> runtime/caml/misc.h
+          echo '#define strcmp_os wcscmp' >> runtime/caml/misc.h
+          printf %s "$STR_UTF16" > utf16.ref
+          printf %s "$STR_UTF8_ENC" > utf8.ref
+      - name: Build sak
+        run: >
+          cl -std:c11 -experimental:c11atomics -I runtime
+          -D__USE_MINGW_ANSI_STDIO=0 -DUNICODE -D_UNICODE -DWINDOWS_UNICODE=1
+          /Fesak.exe runtime\sak.c
+      - name: Test cross sak
+        run: |
+          .\sak.exe encode-C-utf16-literal "${env:TESTDIR}" > utf16
+          git diff --no-index utf16.ref utf16
+          .\sak.exe encode-C-utf8-literal "${env:TESTDIR}" > utf8
+          git diff --no-index utf8.ref utf8
+
+  cross-arm-linux:
+    runs-on: ubuntu-latest
+    needs: non-cross
+    steps:
+      - name: Download Artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: non-cross-ocaml
+      - name: Install non-cross OCaml and set up environment
+        run: |
+          set -x
+          tar xaf ocaml.tar.zst -C "$HOME"
+          rm -f ocaml.tar.zst
+          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+          sudo apt-get install -y gcc-aarch64-linux-gnu qemu-user
+      - name: Checkout OCaml
+        uses: actions/checkout@v4
+        with:
+          submodules: true
+          persist-credentials: false
+      - name: Configure, build and install Linux-to-Windows OCaml
+        run: |
+          set -x
+          if ! ./configure --prefix="$HOME/cross" --target=aarch64-linux-gnu ;
+          then
+            cat config.log
+            exit 1
+          fi
+          make crossopt -j
+          make installcross
+      - name: Show opt.opt configuration
+        run: |
+          $HOME/cross/bin/ocamlopt.opt -config
+      - name: Cross compile a small program
+        run: |
+          printf %s "$EXAMPLE_PROGRAM$COMPLIBS_PROG_AARCH64" > example.ml
+          set -x
+          cat example.ml
+          $HOME/cross/bin/ocamlopt.opt -I $HOME/cross/lib/ocaml/compiler-libs/ ocamlcommon.cmxa ocamloptcomp.cmxa example.ml -o example -verbose
+      - name: Run the small example program
+        run: |
+          set -x
+          qemu-aarch64 -L /usr/aarch64-linux-gnu example
+      - name: Test cross sak
+        run: |
+          printf %s "$STR_UTF16" > utf16.ref
+          printf %s "$STR_UTF8" > utf8.ref
+          set -x
+          runtime/sak encode-C-utf16-literal "$TESTDIR" > utf16
+          git diff --no-index utf16.ref utf16
+          runtime/sak encode-C-utf8-literal "$TESTDIR" > utf8
+          git diff --no-index utf8.ref utf8
+
+  cross-android:
+    runs-on: ubuntu-latest
+    needs: non-cross
+    steps:
+      - name: Download Artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: non-cross-ocaml
+      - name: Install non-cross OCaml
+        run: |
+          set -x
+          tar xaf ocaml.tar.zst -C "$HOME"
+          rm -f ocaml.tar.zst
+          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+      - name: Restore the Android NDK from cache
+        uses: actions/cache/restore@v4
+        id: cache
+        with:
+          path: |
+            /home/runner/android
+          key: android-ndk
+      - name: Download the Android NDK
+        run: |
+          set -x
+          mkdir -p "$HOME/android"
+          cd "$HOME/android"
+          wget --no-verbose https://dl.google.com/android/repository/android-ndk-r27b-linux.zip
+          unzip android-ndk-r27b-linux.zip
+          rm android-ndk-r27b-linux.zip
+        if: steps.cache.outputs.cache-hit != 'true'
+      - name: Save the Android NDK to cache
+        uses: actions/cache/save@v4
+        with:
+          path: |
+            /home/runner/android
+          key: android-ndk
+        if: steps.cache.outputs.cache-hit != 'true'
+      - name: Checkout OCaml
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Configure, build and install Linux-to-Android OCaml
+        env:
+          TARGET: x86_64-linux-android21
+          TOOLDIR: android-ndk-r27b/toolchains/llvm/prebuilt/linux-x86_64/bin
+        run: |
+          DIR="$HOME/android/$TOOLDIR"
+          set -x
+          # Hack around the fact that pthread_cancel isn't available on Android
+          # So the result program should _not_ be run with cleanup on exit
+          # (so no `c=1` in `OCAMLRUNPARAM`)
+          if ! ./configure --prefix="$HOME/cross" --target=$TARGET \
+                   --with-target-libdir="/dummy/directory" \
+                   CC="$DIR/clang --target=$TARGET" \
+                   CPPFLAGS='-Dpthread_cancel=assert' \
+                   AR="$DIR/llvm-ar" \
+                   PARTIALLD="$DIR/ld -r" \
+                   RANLIB="$DIR/llvm-ranlib" \
+                   STRIP="$DIR/llvm-strip" ; then
+            cat config.log
+            exit 1
+          fi
+          make crossopt -j
+          make installcross
+      - name: Show opt.opt configuration
+        run: |
+          $HOME/cross/bin/ocamlopt.opt -config
+      - name: Cross compile a small program
+        run: |
+          printf %s "$EXAMPLE_PROGRAM" > example.ml
+          set -x
+          cat example.ml
+          $HOME/cross/bin/ocamlopt.opt example.ml -o example -verbose
+          file example
+      - name: Run example
+        uses: reactivecircus/android-emulator-runner@v2
+        with:
+          api-level: 21
+          arch: x86_64
+          disable-animations: true
+          script: |
+            adb push example /data/local/tmp/example
+            adb shell /data/local/tmp/example