tools/jdk/java_toolchain_default.bzl

# Copyright 2020 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Bazel rules for creating Java toolchains."""

_DEFAULT_JAVACOPTS = [
    "-XDskipDuplicateBridges=true",
    "-g",
    "-parameters",
]

# JVM options, without patching java.compiler and jdk.compiler modules.
JDK9_JVM_OPTS = [
    # Allow JavaBuilder to access internal javac APIs.
    "--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED",
    "--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
    "--add-exports=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED",
    "--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
    "--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
    "--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
    "--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
    "--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",

    # quiet warnings from com.google.protobuf.UnsafeUtil,
    # see: https://github.com/google/protobuf/issues/3781
    # and: https://github.com/bazelbuild/bazel/issues/5599
    "--add-opens=java.base/java.nio=ALL-UNNAMED",
    "--add-opens=java.base/java.lang=ALL-UNNAMED",
]

# java_toolchain parameters without specifying javac, java.compiler,
# jdk.compiler module, and jvm_opts
_BASE_TOOLCHAIN_CONFIGURATION = dict(
    forcibly_disable_header_compilation = False,
    genclass = [":GenClass"],
    header_compiler = [":TurbineDirect"],
    header_compiler_direct = [":TurbineDirect"],
    ijar = [":ijar"],
    javabuilder = [":JavaBuilder"],
    javac_supports_workers = True,
    jacocorunner = ":jacoco_coverage_runner_filegroup",
    jvm_opts = JDK9_JVM_OPTS,
    misc = _DEFAULT_JAVACOPTS,
    singlejar = [":singlejar"],
    # Code to enumerate target JVM boot classpath uses host JVM. Because
    # java_runtime-s are involved, its implementation is in @bazel_tools.
    bootclasspath = ["@bazel_tools//tools/jdk:platformclasspath"],
    source_version = "8",
    target_version = "8",
)

def java_toolchain_default(name, **kwargs):
    """Defines a java_toolchain with appropriate defaults for Bazel."""

    toolchain_args = dict(_BASE_TOOLCHAIN_CONFIGURATION)
    toolchain_args.update(kwargs)
    native.java_toolchain(
        name = name,
        **toolchain_args
    )