Add support for cross-compiling for s390x platform

buildscripts/build_docker.sh

@@ -2,4 +2,6 @@
 set -eu -o pipefail
 
 readonly buildscripts_dir="$(dirname "$(readlink -f "$0")")"
-docker build -t grpc-java-artifacts "$buildscripts_dir"/grpc-java-artifacts
+docker build -t grpc-java-artifacts-x86 "$buildscripts_dir"/grpc-java-artifacts
+docker build -t grpc-java-artifacts-multiarch -f "$buildscripts_dir"/grpc-java-artifacts/Dockerfile.multiarch.base "$buildscripts_dir"/grpc-java-artifacts
+

buildscripts/build_s390x_artifacts_in_docker.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+set -exu -o pipefail
+
+# first we need to install the prerequisites required for s390x cross compilation
+apt-get update && apt-get install -y g++-s390x-linux-gnu
+
+# now kick off the build for the mvn artifacts for s390x
+# mvn artifacts are stored in grpc-java/mvn-artifacts/
+SKIP_TESTS=true ARCH=s390_64 "$(dirname $0)"/kokoro/unix.sh
+

buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base

@@ -0,0 +1,15 @@
+FROM ubuntu:22.04
+
+# make sure apt-get works in unattended mode
+ENV DEBIAN_FRONTEND=noninteractive
+
+# install the OS-level prerequisites for building protobuf and running the gradle build
+RUN apt-get update && \
+    apt-get upgrade -y && \
+    apt-get install -y --no-install-recommends ca-certificates build-essential wget curl openjdk-8-jdk && \
+    apt-get autoclean -y && \
+    apt-get autoremove -y && \
+    rm -rf /var/lib/apt/lists/*
+
+ENV JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
+

buildscripts/kokoro/linux_artifacts.sh

@@ -11,7 +11,7 @@ readonly GRPC_JAVA_DIR="$(cd "$(dirname "$0")"/../.. && pwd)"
 trap spongify_logs EXIT
 
 "$GRPC_JAVA_DIR"/buildscripts/build_docker.sh
-"$GRPC_JAVA_DIR"/buildscripts/run_in_docker.sh /grpc-java/buildscripts/build_artifacts_in_docker.sh
+"$GRPC_JAVA_DIR"/buildscripts/run_in_docker.sh grpc-java-artifacts-x86 /grpc-java/buildscripts/build_artifacts_in_docker.sh
 
 # grpc-android, grpc-cronet and grpc-binder require the Android SDK, so build outside of Docker and
 # use --include-build for its grpc-core dependency
@@ -53,3 +53,9 @@ SKIP_TESTS=true ARCH=aarch_64 "$GRPC_JAVA_DIR"/buildscripts/kokoro/unix.sh
 # for ppc64le platform
 sudo apt-get install -y g++-powerpc64le-linux-gnu
 SKIP_TESTS=true ARCH=ppcle_64 "$GRPC_JAVA_DIR"/buildscripts/kokoro/unix.sh
+
+# for s390x platform
+# building these artifacts inside a Docker container as we have specific requirements
+# for GCC (version 11.x needed) which in turn requires Ubuntu 22.04 LTS
+"$GRPC_JAVA_DIR"/buildscripts/run_in_docker.sh grpc-java-artifacts-multiarch /grpc-java/buildscripts/build_s390x_artifacts_in_docker.sh
+

buildscripts/kokoro/unix.sh

@@ -11,6 +11,8 @@
 #  ARCH=aarch_64 ./buildscripts/kokoro/unix.sh
 # For ppc64le arch:
 #  ARCH=ppcle_64 ./buildscripts/kokoro/unix.sh
+# For s390x arch:
+#  ARCH=s390_64 ./buildscripts/kokoro/unix.sh
 
 # This script assumes `set -e`. Removing it may lead to undefined behavior.
 set -exu -o pipefail
@@ -91,7 +93,7 @@ fi
 LOCAL_MVN_TEMP=$(mktemp -d)
 # Note that this disables parallel=true from GRADLE_FLAGS
 if [[ -z "${ALL_ARTIFACTS:-}" ]]; then
-  if [[ "$ARCH" = "aarch_64" || "$ARCH" = "ppcle_64" ]]; then
+  if [[ "$ARCH" = "aarch_64" || "$ARCH" = "ppcle_64" || "$ARCH" = "s390_64" ]]; then
     GRADLE_FLAGS+=" -x grpc-compiler:generateTestProto -x grpc-compiler:generateTestLiteProto"
     GRADLE_FLAGS+=" -x grpc-compiler:testGolden -x grpc-compiler:testLiteGolden"
     GRADLE_FLAGS+=" -x grpc-compiler:testDeprecatedGolden -x grpc-compiler:testDeprecatedLiteGolden"

buildscripts/kokoro/upload_artifacts.sh

@@ -37,6 +37,9 @@ LOCAL_OTHER_ARTIFACTS="$KOKORO_GFILE_DIR"/github/grpc-java/artifacts/
 # for linux ppc64le platform
 [[ "$(find "$LOCAL_MVN_ARTIFACTS" -type f -iname 'protoc-gen-grpc-java-*-linux-ppcle_64.exe' | wc -l)" != '0' ]]
 
+# for linux s390x platform
+[[ "$(find "$LOCAL_MVN_ARTIFACTS" -type f -iname 'protoc-gen-grpc-java-*-linux-s390_64.exe' | wc -l)" != '0' ]]
+
 # from macos job:
 [[ "$(find "$LOCAL_MVN_ARTIFACTS" -type f -iname 'protoc-gen-grpc-java-*-osx-x86_64.exe' | wc -l)" != '0' ]]
 # copy all x86 artifacts to aarch until native artifacts are built

buildscripts/make_dependencies.sh

@@ -41,6 +41,8 @@ else
     ./configure --disable-shared --host=aarch64-linux-gnu --prefix="$INSTALL_DIR"
   elif [[ "$ARCH" == ppc* ]]; then
     ./configure --disable-shared --host=powerpc64le-linux-gnu --prefix="$INSTALL_DIR"
+  elif [[ "$ARCH" == s390* ]]; then
+    ./configure --disable-shared --host=s390x-linux-gnu --prefix="$INSTALL_DIR"
   fi
   # the same source dir is used for 32 and 64 bit builds, so we need to clean stale data first
   make clean

buildscripts/run_in_docker.sh

@@ -10,6 +10,8 @@ quote() {
   done
 }
 
+readonly docker_image=$1; shift
+
 readonly grpc_java_dir="$(dirname "$(readlink -f "$0")")/.."
 if [[ -t 0 ]]; then
   DOCKER_ARGS="-it"
@@ -21,5 +23,5 @@ fi
 # the original exit code. $DOCKER_ARGS can not be quoted, otherwise it becomes a '' which confuses
 # docker.
 exec docker run $DOCKER_ARGS --rm=true -v "${grpc_java_dir}":/grpc-java -w /grpc-java \
-  grpc-java-artifacts \
+  $docker_image \
   bash -c "function fixFiles() { chown -R $(id -u):$(id -g) /grpc-java; }; trap fixFiles EXIT; $(quote "$@")"

compiler/build.gradle

@@ -58,7 +58,10 @@ model {
                 cppCompiler.executable = 'aarch64-linux-gnu-g++'
                 linker.executable = 'aarch64-linux-gnu-g++'
             }
-            target("s390_64")
+            target("s390_64") {
+                cppCompiler.executable = 's390x-linux-gnu-g++'
+                linker.executable = 's390x-linux-gnu-g++'
+            }
             target("loongarch_64")
         }
         clang(Clang) {

compiler/check-artifact.sh

@@ -65,6 +65,10 @@ checkArch ()
         format="$(powerpc64le-linux-gnu-objdump -f "$1" | grep -o "file format .*$" | grep -o "[^ ]*$")"
         echo Format=$format
         assertEq "$format" "elf64-powerpcle" $LINENO
+      elif [[ "$ARCH" == s390_64 ]]; then
+        format="$(s390x-linux-gnu-objdump -f "$1" | grep -o "file format .*$" | grep -o "[^ ]*$")"
+        echo Format=$format
+        assertEq "$format" "elf64-s390" $LINENO
       else
         fail "Unsupported arch: $ARCH"
       fi
@@ -115,6 +119,9 @@ checkDependencies ()
     elif [[ "$ARCH" == ppcle_64 ]]; then
       dump_cmd='powerpc64le-linux-gnu-objdump -x '"$1"' |grep "NEEDED"'
       white_list="linux-vdso64\.so\.1\|libpthread\.so\.0\|libm\.so\.6\|libc\.so\.6\|ld64\.so\.2"
+    elif [[ "$ARCH" == s390_64 ]]; then
+      dump_cmd='s390x-linux-gnu-objdump -x '"$1"' |grep "NEEDED"'
+      white_list="linux-vdso64\.so\.1\|libpthread\.so\.0\|libm\.so\.6\|libc\.so\.6\|ld64\.so\.1"
     fi
   elif [[ "$OS" == osx ]]; then
     dump_cmd='otool -L '"$1"' | fgrep dylib'