third_party/nix: introduce toolchain bundle
This introduces a nix derivation that builds a musl amd64/aarch64
toolchain sysroot.
Change-Id: Iba082edb8fd1f2ab580020bb1c7339a76487f3c8
Reviewed-on: https://review.monogon.dev/c/monogon/+/4006
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/build/toolchain/toolchain-bundle/toolchain.bzl b/build/toolchain/toolchain-bundle/toolchain.bzl
new file mode 100644
index 0000000..a2b7df2
--- /dev/null
+++ b/build/toolchain/toolchain-bundle/toolchain.bzl
@@ -0,0 +1,188 @@
+load("@rules_foreign_cc//toolchains/native_tools:native_tools_toolchain.bzl", "native_tool_toolchain")
+
+# Copied from bazel-contrib/rules_foreign_cc licensed under Apache-2.0
+def _current_toolchain_impl(ctx):
+ toolchain = ctx.toolchains[ctx.attr._toolchain]
+
+ if toolchain.data.target:
+ return [
+ toolchain,
+ platform_common.TemplateVariableInfo(toolchain.data.env),
+ DefaultInfo(
+ files = toolchain.data.target.files,
+ runfiles = toolchain.data.target.default_runfiles,
+ ),
+ ]
+ return [
+ toolchain,
+ platform_common.TemplateVariableInfo(toolchain.data.env),
+ DefaultInfo(),
+ ]
+
+def current_toolchain(name):
+ return rule(
+ implementation = _current_toolchain_impl,
+ attrs = {
+ "_toolchain": attr.string(default = "//build/toolchain/toolchain-bundle:%s_toolchain" % name),
+ },
+ toolchains = [
+ "//build/toolchain/toolchain-bundle:%s_toolchain" % name,
+ ],
+ )
+
+def toolchain_for(name, config):
+ native.toolchain_type(
+ name = "%s_toolchain" % name,
+ )
+
+ config.current_toolchain_func(
+ name = name,
+ )
+
+ native.toolchain(
+ name = "%s_linux_x86_64_toolchain" % name,
+ exec_compatible_with = [
+ "@platforms//os:linux",
+ "@platforms//cpu:x86_64",
+ ],
+ toolchain = ":%s_linux_x86_64" % name,
+ toolchain_type = ":%s_toolchain" % name,
+ )
+
+ native.toolchain(
+ name = "%s_linux_aarch64_toolchain" % name,
+ exec_compatible_with = [
+ "@platforms//os:linux",
+ "@platforms//cpu:aarch64",
+ ],
+ toolchain = ":%s_linux_aarch64" % name,
+ toolchain_type = ":%s_toolchain" % name,
+ )
+
+ native_tool_toolchain(
+ name = "%s_linux_aarch64" % name,
+ env = {
+ name.upper(): "$(execpath @toolchain-bundle-aarch64-unknown-linux-musl//:%s)" % config.target,
+ },
+ target = "@toolchain-bundle-aarch64-unknown-linux-musl//:%s" % config.target,
+ )
+
+ native_tool_toolchain(
+ name = "%s_linux_x86_64" % name,
+ env = {
+ name.upper(): "$(execpath @toolchain-bundle-x86_64-unknown-linux-musl//:%s)" % config.target,
+ },
+ target = "@toolchain-bundle-x86_64-unknown-linux-musl//:%s" % config.target,
+ )
+
+current_qemu_img_toolchain = current_toolchain("qemu-img")
+current_qemu_kvm_toolchain = current_toolchain("qemu-kvm")
+current_make_toolchain = current_toolchain("make")
+current_strace_toolchain = current_toolchain("strace")
+current_nasm_toolchain = current_toolchain("nasm")
+current_bison_toolchain = current_toolchain("bison")
+current_flex_toolchain = current_toolchain("flex")
+current_m4_toolchain = current_toolchain("m4")
+current_bc_toolchain = current_toolchain("bc")
+current_busybox_toolchain = current_toolchain("busybox")
+current_diff_toolchain = current_toolchain("diff")
+current_perl_toolchain = current_toolchain("perl")
+current_iasl_toolchain = current_toolchain("iasl")
+current_lz4_toolchain = current_toolchain("lz4")
+
+TOOLCHAINS = {
+ "qemu-img": struct(
+ target = "bin/qemu-img",
+ current_toolchain_func = current_qemu_img_toolchain,
+ ),
+ "qemu-kvm": struct(
+ target = "qemu-kvm",
+ current_toolchain_func = current_qemu_kvm_toolchain,
+ ),
+ "make": struct(
+ target = "bin/make",
+ current_toolchain_func = current_make_toolchain,
+ ),
+ "strace": struct(
+ target = "bin/strace",
+ current_toolchain_func = current_strace_toolchain,
+ ),
+ "nasm": struct(
+ target = "bin/nasm",
+ current_toolchain_func = current_nasm_toolchain,
+ ),
+ "bison": struct(
+ target = "bison",
+ current_toolchain_func = current_bison_toolchain,
+ ),
+ "flex": struct(
+ target = "bin/flex",
+ current_toolchain_func = current_flex_toolchain,
+ ),
+ "m4": struct(
+ target = "bin/m4",
+ current_toolchain_func = current_m4_toolchain,
+ ),
+ "bc": struct(
+ target = "bin/bc",
+ current_toolchain_func = current_bc_toolchain,
+ ),
+ "diff": struct(
+ target = "bin/diff",
+ current_toolchain_func = current_diff_toolchain,
+ ),
+ "iasl": struct(
+ target = "bin/iasl",
+ current_toolchain_func = current_iasl_toolchain,
+ ),
+ "busybox": struct(
+ target = "busybox",
+ current_toolchain_func = current_busybox_toolchain,
+ ),
+ "perl": struct(
+ target = "perl",
+ current_toolchain_func = current_perl_toolchain,
+ ),
+ "lz4": struct(
+ target = "bin/lz4",
+ current_toolchain_func = current_lz4_toolchain,
+ ),
+}
+
+def build_toolchain_env(ctx, toolchains):
+ toolchain_info = [ctx.toolchains[t] for t in toolchains]
+ env = dict([(k, v) for t in toolchain_info for k, v in t.data.env.items()])
+ env = env | {"TOOL_PATH": ":".join([t.data.target.files.to_list()[0].path.rsplit("/", 1)[0] for t in toolchain_info])}
+
+ inputs = depset(transitive = [
+ depset(transitive = [t.data.target.files, t.data.target.default_runfiles.files])
+ for t in toolchain_info
+ ])
+
+ return env, inputs
+
+TOOLCHAIN_ENV_SETUP = """
+set -e
+
+# Iterate over all environment variables and expand paths that are
+# either external or bazel-out.
+for name in $(env | cut -d= -f1); do
+ val="${!name}"
+ [[ "$val" != *external/* && "$val" != *bazel-out/* ]] && continue # Quick skip
+
+ sep=' '; [[ $name == "TOOL_PATH" ]] && sep=':' # Set separator: : for PATH, space otherwise
+ IFS=$sep read -r -a items <<< "$val" # Split value into array using correct separator
+
+ for i in "${!items[@]}"; do
+ key="${items[i]%%=*}"; v="${items[i]#*=}" # Handle 'key=val' and standalone paths
+ if [[ ( $v == external/* || $v == bazel-out/* ) && -e "$v" ]]; then
+ [ "$key" = "$v" ] && items[i]=$(realpath -s "$v") || items[i]="$key=$(realpath -s "$v")"
+ fi
+ done
+ export "$name=$(IFS=$sep; echo "${items[*]}")" # Re-export with correct separator
+done
+
+# Add our now expanded TOOL_PATH to PATH
+PATH="$PATH:$TOOL_PATH"
+
+"""