1 //! Compilation of native dependencies like LLVM.
3 //! Native projects like LLVM unfortunately aren't suited just yet for
4 //! compilation in build scripts that Cargo has. This is because the
5 //! compilation takes a *very* long time but also because we don't want to
6 //! compile LLVM 3 times as part of a normal bootstrap (we want it cached).
8 //! LLVM and compiler-rt are essentially just wired up to everything else to
9 //! ensure that they're always in place if needed.
12 use std::ffi::OsString;
13 use std::fs::{self, File};
14 use std::path::{Path, PathBuf};
15 use std::process::Command;
17 use build_helper::{output, t};
19 use crate::builder::{Builder, RunConfig, ShouldRun, Step};
20 use crate::cache::Interned;
22 use crate::util::{self, exe};
24 use build_helper::up_to_date;
26 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
28 pub target: Interned<String>,
32 type Output = PathBuf; // path to llvm-config
34 const ONLY_HOSTS: bool = true;
36 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
37 run.path("src/llvm-project").path("src/llvm-project/llvm").path("src/llvm")
40 fn make_run(run: RunConfig<'_>) {
41 run.builder.ensure(Llvm { target: run.target });
44 /// Compile LLVM for `target`.
45 fn run(self, builder: &Builder<'_>) -> PathBuf {
46 let target = self.target;
48 // If we're using a custom LLVM bail out here, but we can only use a
49 // custom LLVM for the build triple.
50 if let Some(config) = builder.config.target_config.get(&target) {
51 if let Some(ref s) = config.llvm_config {
52 check_llvm_version(builder, s);
53 return s.to_path_buf();
57 let llvm_info = &builder.in_tree_llvm_info;
58 let root = "src/llvm-project/llvm";
59 let out_dir = builder.llvm_out(target);
60 let mut llvm_config_ret_dir = builder.llvm_out(builder.config.build);
61 if !builder.config.build.contains("msvc") || builder.config.ninja {
62 llvm_config_ret_dir.push("build");
64 llvm_config_ret_dir.push("bin");
66 let build_llvm_config =
67 llvm_config_ret_dir.join(exe("llvm-config", &*builder.config.build));
68 let done_stamp = out_dir.join("llvm-finished-building");
70 if done_stamp.exists() {
71 if builder.config.llvm_skip_rebuild {
74 Using a potentially stale build of LLVM; \
75 This may not behave well.",
77 return build_llvm_config;
80 if let Some(llvm_commit) = llvm_info.sha() {
81 let done_contents = t!(fs::read(&done_stamp));
83 // If LLVM was already built previously and the submodule's commit didn't change
84 // from the previous build, then no action is required.
85 if done_contents == llvm_commit.as_bytes() {
86 return build_llvm_config;
90 "Could not determine the LLVM submodule commit hash. \
91 Assuming that an LLVM rebuild is not necessary.",
93 builder.info(&format!(
94 "To force LLVM to rebuild, remove the file `{}`",
97 return build_llvm_config;
101 builder.info(&format!("Building LLVM for {}", target));
102 let _time = util::timeit(&builder);
103 t!(fs::create_dir_all(&out_dir));
105 // http://llvm.org/docs/CMake.html
106 let mut cfg = cmake::Config::new(builder.src.join(root));
108 let profile = match (builder.config.llvm_optimize, builder.config.llvm_release_debuginfo) {
109 (false, _) => "Debug",
110 (true, false) => "Release",
111 (true, true) => "RelWithDebInfo",
114 // NOTE: remember to also update `config.toml.example` when changing the
116 let llvm_targets = match &builder.config.llvm_targets {
119 "AArch64;ARM;Hexagon;MSP430;Mips;NVPTX;PowerPC;RISCV;\
120 Sparc;SystemZ;WebAssembly;X86"
124 let llvm_exp_targets = match builder.config.llvm_experimental_targets {
129 let assertions = if builder.config.llvm_assertions { "ON" } else { "OFF" };
131 cfg.out_dir(&out_dir)
133 .define("LLVM_ENABLE_ASSERTIONS", assertions)
134 .define("LLVM_TARGETS_TO_BUILD", llvm_targets)
135 .define("LLVM_EXPERIMENTAL_TARGETS_TO_BUILD", llvm_exp_targets)
136 .define("LLVM_INCLUDE_EXAMPLES", "OFF")
137 .define("LLVM_INCLUDE_TESTS", "OFF")
138 .define("LLVM_INCLUDE_DOCS", "OFF")
139 .define("LLVM_INCLUDE_BENCHMARKS", "OFF")
140 .define("LLVM_ENABLE_ZLIB", "OFF")
141 .define("WITH_POLLY", "OFF")
142 .define("LLVM_ENABLE_TERMINFO", "OFF")
143 .define("LLVM_ENABLE_LIBEDIT", "OFF")
144 .define("LLVM_ENABLE_BINDINGS", "OFF")
145 .define("LLVM_ENABLE_Z3_SOLVER", "OFF")
146 .define("LLVM_PARALLEL_COMPILE_JOBS", builder.jobs().to_string())
147 .define("LLVM_TARGET_ARCH", target.split('-').next().unwrap())
148 .define("LLVM_DEFAULT_TARGET_TRIPLE", target);
150 if builder.config.llvm_thin_lto {
151 cfg.define("LLVM_ENABLE_LTO", "Thin");
152 if !target.contains("apple") {
153 cfg.define("LLVM_ENABLE_LLD", "ON");
157 // This setting makes the LLVM tools link to the dynamic LLVM library,
158 // which saves both memory during parallel links and overall disk space
159 // for the tools. We don't do this on every platform as it doesn't work
160 // equally well everywhere.
161 if builder.llvm_link_tools_dynamically(target) {
162 cfg.define("LLVM_LINK_LLVM_DYLIB", "ON");
165 // For distribution we want the LLVM tools to be *statically* linked to libstdc++
166 if builder.config.llvm_tools_enabled || builder.config.lldb_enabled {
167 if !target.contains("msvc") {
168 if target.contains("apple") {
169 cfg.define("CMAKE_EXE_LINKER_FLAGS", "-static-libstdc++");
171 cfg.define("CMAKE_EXE_LINKER_FLAGS", "-Wl,-Bsymbolic -static-libstdc++");
176 if target.contains("msvc") {
177 cfg.define("LLVM_USE_CRT_DEBUG", "MT");
178 cfg.define("LLVM_USE_CRT_RELEASE", "MT");
179 cfg.define("LLVM_USE_CRT_RELWITHDEBINFO", "MT");
180 cfg.static_crt(true);
183 if target.starts_with("i686") {
184 cfg.define("LLVM_BUILD_32_BITS", "ON");
187 let mut enabled_llvm_projects = Vec::new();
189 if util::forcing_clang_based_tests() {
190 enabled_llvm_projects.push("clang");
191 enabled_llvm_projects.push("compiler-rt");
194 if builder.config.lldb_enabled {
195 enabled_llvm_projects.push("clang");
196 enabled_llvm_projects.push("lldb");
197 // For the time being, disable code signing.
198 cfg.define("LLDB_CODESIGN_IDENTITY", "");
199 cfg.define("LLDB_NO_DEBUGSERVER", "ON");
201 // LLDB requires libxml2; but otherwise we want it to be disabled.
202 // See https://github.com/rust-lang/rust/pull/50104
203 cfg.define("LLVM_ENABLE_LIBXML2", "OFF");
206 if !enabled_llvm_projects.is_empty() {
207 enabled_llvm_projects.sort();
208 enabled_llvm_projects.dedup();
209 cfg.define("LLVM_ENABLE_PROJECTS", enabled_llvm_projects.join(";"));
212 if let Some(num_linkers) = builder.config.llvm_link_jobs {
214 cfg.define("LLVM_PARALLEL_LINK_JOBS", num_linkers.to_string());
218 // http://llvm.org/docs/HowToCrossCompileLLVM.html
219 if target != builder.config.build {
220 builder.ensure(Llvm { target: builder.config.build });
221 // FIXME: if the llvm root for the build triple is overridden then we
222 // should use llvm-tblgen from there, also should verify that it
223 // actually exists most of the time in normal installs of LLVM.
224 let host = builder.llvm_out(builder.config.build).join("bin/llvm-tblgen");
225 cfg.define("CMAKE_CROSSCOMPILING", "True").define("LLVM_TABLEGEN", &host);
227 if target.contains("netbsd") {
228 cfg.define("CMAKE_SYSTEM_NAME", "NetBSD");
229 } else if target.contains("freebsd") {
230 cfg.define("CMAKE_SYSTEM_NAME", "FreeBSD");
231 } else if target.contains("windows") {
232 cfg.define("CMAKE_SYSTEM_NAME", "Windows");
235 cfg.define("LLVM_NATIVE_BUILD", builder.llvm_out(builder.config.build).join("build"));
238 if let Some(ref suffix) = builder.config.llvm_version_suffix {
239 // Allow version-suffix="" to not define a version suffix at all.
240 if !suffix.is_empty() {
241 cfg.define("LLVM_VERSION_SUFFIX", suffix);
245 format!("-rust-{}-{}", channel::CFG_RELEASE_NUM, builder.config.channel);
246 cfg.define("LLVM_VERSION_SUFFIX", default_suffix);
249 if let Some(ref linker) = builder.config.llvm_use_linker {
250 cfg.define("LLVM_USE_LINKER", linker);
253 if let Some(true) = builder.config.llvm_allow_old_toolchain {
254 cfg.define("LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN", "YES");
257 if let Some(ref python) = builder.config.python {
258 cfg.define("PYTHON_EXECUTABLE", python);
261 configure_cmake(builder, target, &mut cfg, true);
263 // FIXME: we don't actually need to build all LLVM tools and all LLVM
264 // libraries here, e.g., we just want a few components and a few
265 // tools. Figure out how to filter them down and only build the right
266 // tools and libs on all platforms.
268 if builder.config.dry_run {
269 return build_llvm_config;
274 t!(fs::write(&done_stamp, llvm_info.sha().unwrap_or("")));
280 fn check_llvm_version(builder: &Builder<'_>, llvm_config: &Path) {
281 if !builder.config.llvm_version_check {
285 if builder.config.dry_run {
289 let mut cmd = Command::new(llvm_config);
290 let version = output(cmd.arg("--version"));
291 let mut parts = version.split('.').take(2).filter_map(|s| s.parse::<u32>().ok());
292 if let (Some(major), Some(_minor)) = (parts.next(), parts.next()) {
297 panic!("\n\nbad LLVM version: {}, need >=7.0\n\n", version)
301 builder: &Builder<'_>,
302 target: Interned<String>,
303 cfg: &mut cmake::Config,
304 use_compiler_launcher: bool,
306 // Do not print installation messages for up-to-date files.
307 // LLVM and LLD builds can produce a lot of those and hit CI limits on log size.
308 cfg.define("CMAKE_INSTALL_MESSAGE", "LAZY");
310 if builder.config.ninja {
311 cfg.generator("Ninja");
313 cfg.target(&target).host(&builder.config.build);
315 let sanitize_cc = |cc: &Path| {
316 if target.contains("msvc") {
317 OsString::from(cc.to_str().unwrap().replace("\\", "/"))
319 cc.as_os_str().to_owned()
323 // MSVC with CMake uses msbuild by default which doesn't respect these
324 // vars that we'd otherwise configure. In that case we just skip this
326 if target.contains("msvc") && !builder.config.ninja {
330 let (cc, cxx) = match builder.config.llvm_clang_cl {
331 Some(ref cl) => (cl.as_ref(), cl.as_ref()),
332 None => (builder.cc(target), builder.cxx(target).unwrap()),
335 // Handle msvc + ninja + ccache specially (this is what the bots use)
336 if target.contains("msvc") && builder.config.ninja && builder.config.ccache.is_some() {
337 let mut wrap_cc = env::current_exe().expect("failed to get cwd");
338 wrap_cc.set_file_name("sccache-plus-cl.exe");
340 cfg.define("CMAKE_C_COMPILER", sanitize_cc(&wrap_cc))
341 .define("CMAKE_CXX_COMPILER", sanitize_cc(&wrap_cc));
342 cfg.env("SCCACHE_PATH", builder.config.ccache.as_ref().unwrap())
343 .env("SCCACHE_TARGET", target)
344 .env("SCCACHE_CC", &cc)
345 .env("SCCACHE_CXX", &cxx);
347 // Building LLVM on MSVC can be a little ludicrous at times. We're so far
348 // off the beaten path here that I'm not really sure this is even half
349 // supported any more. Here we're trying to:
351 // * Build LLVM on MSVC
352 // * Build LLVM with `clang-cl` instead of `cl.exe`
353 // * Build a project with `sccache`
354 // * Build for 32-bit as well
355 // * Build with Ninja
357 // For `cl.exe` there are different binaries to compile 32/64 bit which
358 // we use but for `clang-cl` there's only one which internally
359 // multiplexes via flags. As a result it appears that CMake's detection
360 // of a compiler's architecture and such on MSVC **doesn't** pass any
361 // custom flags we pass in CMAKE_CXX_FLAGS below. This means that if we
362 // use `clang-cl.exe` it's always diagnosed as a 64-bit compiler which
363 // definitely causes problems since all the env vars are pointing to
366 // To hack around this... again... we pass an argument that's
367 // unconditionally passed in the sccache shim. This'll get CMake to
368 // correctly diagnose it's doing a 32-bit compilation and LLVM will
369 // internally configure itself appropriately.
370 if builder.config.llvm_clang_cl.is_some() && target.contains("i686") {
371 cfg.env("SCCACHE_EXTRA_ARGS", "-m32");
374 // If ccache is configured we inform the build a little differently how
375 // to invoke ccache while also invoking our compilers.
376 if use_compiler_launcher {
377 if let Some(ref ccache) = builder.config.ccache {
378 cfg.define("CMAKE_C_COMPILER_LAUNCHER", ccache)
379 .define("CMAKE_CXX_COMPILER_LAUNCHER", ccache);
382 cfg.define("CMAKE_C_COMPILER", sanitize_cc(cc))
383 .define("CMAKE_CXX_COMPILER", sanitize_cc(cxx));
386 cfg.build_arg("-j").build_arg(builder.jobs().to_string());
387 let mut cflags = builder.cflags(target, GitRepo::Llvm).join(" ");
388 if let Some(ref s) = builder.config.llvm_cflags {
389 cflags.push_str(&format!(" {}", s));
391 cfg.define("CMAKE_C_FLAGS", cflags);
392 let mut cxxflags = builder.cflags(target, GitRepo::Llvm).join(" ");
393 if builder.config.llvm_static_stdcpp && !target.contains("msvc") && !target.contains("netbsd") {
394 cxxflags.push_str(" -static-libstdc++");
396 if let Some(ref s) = builder.config.llvm_cxxflags {
397 cxxflags.push_str(&format!(" {}", s));
399 cfg.define("CMAKE_CXX_FLAGS", cxxflags);
400 if let Some(ar) = builder.ar(target) {
401 if ar.is_absolute() {
402 // LLVM build breaks if `CMAKE_AR` is a relative path, for some reason it
403 // tries to resolve this path in the LLVM build directory.
404 cfg.define("CMAKE_AR", sanitize_cc(ar));
408 if let Some(ranlib) = builder.ranlib(target) {
409 if ranlib.is_absolute() {
410 // LLVM build breaks if `CMAKE_RANLIB` is a relative path, for some reason it
411 // tries to resolve this path in the LLVM build directory.
412 cfg.define("CMAKE_RANLIB", sanitize_cc(ranlib));
416 if let Some(ref s) = builder.config.llvm_ldflags {
417 cfg.define("CMAKE_SHARED_LINKER_FLAGS", s);
418 cfg.define("CMAKE_MODULE_LINKER_FLAGS", s);
419 cfg.define("CMAKE_EXE_LINKER_FLAGS", s);
422 if env::var_os("SCCACHE_ERROR_LOG").is_some() {
423 cfg.env("RUSTC_LOG", "sccache=warn");
427 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
429 pub target: Interned<String>,
433 type Output = PathBuf;
434 const ONLY_HOSTS: bool = true;
436 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
437 run.path("src/llvm-project/lld").path("src/tools/lld")
440 fn make_run(run: RunConfig<'_>) {
441 run.builder.ensure(Lld { target: run.target });
444 /// Compile LLVM for `target`.
445 fn run(self, builder: &Builder<'_>) -> PathBuf {
446 if builder.config.dry_run {
447 return PathBuf::from("lld-out-dir-test-gen");
449 let target = self.target;
451 let llvm_config = builder.ensure(Llvm { target: self.target });
453 let out_dir = builder.lld_out(target);
454 let done_stamp = out_dir.join("lld-finished-building");
455 if done_stamp.exists() {
459 builder.info(&format!("Building LLD for {}", target));
460 let _time = util::timeit(&builder);
461 t!(fs::create_dir_all(&out_dir));
463 let mut cfg = cmake::Config::new(builder.src.join("src/llvm-project/lld"));
464 configure_cmake(builder, target, &mut cfg, true);
466 // This is an awful, awful hack. Discovered when we migrated to using
467 // clang-cl to compile LLVM/LLD it turns out that LLD, when built out of
468 // tree, will execute `llvm-config --cmakedir` and then tell CMake about
469 // that directory for later processing. Unfortunately if this path has
470 // forward slashes in it (which it basically always does on Windows)
471 // then CMake will hit a syntax error later on as... something isn't
474 // Instead of attempting to fix this problem in upstream CMake and/or
475 // LLVM/LLD we just hack around it here. This thin wrapper will take the
476 // output from llvm-config and replace all instances of `\` with `/` to
477 // ensure we don't hit the same bugs with escaping. It means that you
478 // can't build on a system where your paths require `\` on Windows, but
479 // there's probably a lot of reasons you can't do that other than this.
480 let llvm_config_shim = env::current_exe().unwrap().with_file_name("llvm-config-wrapper");
481 cfg.out_dir(&out_dir)
483 .env("LLVM_CONFIG_REAL", llvm_config)
484 .define("LLVM_CONFIG_PATH", llvm_config_shim)
485 .define("LLVM_INCLUDE_TESTS", "OFF");
489 t!(File::create(&done_stamp));
494 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
495 pub struct TestHelpers {
496 pub target: Interned<String>,
499 impl Step for TestHelpers {
502 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
503 run.path("src/test/auxiliary/rust_test_helpers.c")
506 fn make_run(run: RunConfig<'_>) {
507 run.builder.ensure(TestHelpers { target: run.target })
510 /// Compiles the `rust_test_helpers.c` library which we used in various
511 /// `run-pass` tests for ABI testing.
512 fn run(self, builder: &Builder<'_>) {
513 if builder.config.dry_run {
516 let target = self.target;
517 let dst = builder.test_helpers_out(target);
518 let src = builder.src.join("src/test/auxiliary/rust_test_helpers.c");
519 if up_to_date(&src, &dst.join("librust_test_helpers.a")) {
523 builder.info("Building test helpers");
524 t!(fs::create_dir_all(&dst));
525 let mut cfg = cc::Build::new();
526 // FIXME: Workaround for https://github.com/emscripten-core/emscripten/issues/9013
527 if target.contains("emscripten") {
531 // We may have found various cross-compilers a little differently due to our
532 // extra configuration, so inform gcc of these compilers. Note, though, that
533 // on MSVC we still need gcc's detection of env vars (ugh).
534 if !target.contains("msvc") {
535 if let Some(ar) = builder.ar(target) {
538 cfg.compiler(builder.cc(target));
541 cfg.cargo_metadata(false)
544 .host(&builder.config.build)
548 .file(builder.src.join("src/test/auxiliary/rust_test_helpers.c"))
549 .compile("rust_test_helpers");
553 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
554 pub struct Sanitizers {
555 pub target: Interned<String>,
558 impl Step for Sanitizers {
559 type Output = Vec<SanitizerRuntime>;
561 fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
562 run.path("src/llvm-project/compiler-rt").path("src/sanitizers")
565 fn make_run(run: RunConfig<'_>) {
566 run.builder.ensure(Sanitizers { target: run.target });
569 /// Builds sanitizer runtime libraries.
570 fn run(self, builder: &Builder<'_>) -> Self::Output {
571 let compiler_rt_dir = builder.src.join("src/llvm-project/compiler-rt");
572 if !compiler_rt_dir.exists() {
576 let out_dir = builder.native_dir(self.target).join("sanitizers");
577 let runtimes = supported_sanitizers(&out_dir, self.target, &builder.config.channel);
578 if runtimes.is_empty() {
582 let llvm_config = builder.ensure(Llvm { target: builder.config.build });
583 if builder.config.dry_run {
587 let done_stamp = out_dir.join("sanitizers-finished-building");
588 if done_stamp.exists() {
589 builder.info(&format!(
590 "Assuming that sanitizers rebuild is not necessary. \
591 To force a rebuild, remove the file `{}`",
597 builder.info(&format!("Building sanitizers for {}", self.target));
598 let _time = util::timeit(&builder);
600 let mut cfg = cmake::Config::new(&compiler_rt_dir);
601 cfg.profile("Release");
602 cfg.define("CMAKE_C_COMPILER_TARGET", self.target);
603 cfg.define("COMPILER_RT_BUILD_BUILTINS", "OFF");
604 cfg.define("COMPILER_RT_BUILD_CRT", "OFF");
605 cfg.define("COMPILER_RT_BUILD_LIBFUZZER", "OFF");
606 cfg.define("COMPILER_RT_BUILD_PROFILE", "OFF");
607 cfg.define("COMPILER_RT_BUILD_SANITIZERS", "ON");
608 cfg.define("COMPILER_RT_BUILD_XRAY", "OFF");
609 cfg.define("COMPILER_RT_DEFAULT_TARGET_ONLY", "ON");
610 cfg.define("COMPILER_RT_USE_LIBCXX", "OFF");
611 cfg.define("LLVM_CONFIG_PATH", &llvm_config);
613 // On Darwin targets the sanitizer runtimes are build as universal binaries.
614 // Unfortunately sccache currently lacks support to build them successfully.
615 // Disable compiler launcher on Darwin targets to avoid potential issues.
616 let use_compiler_launcher = !self.target.contains("apple-darwin");
617 configure_cmake(builder, self.target, &mut cfg, use_compiler_launcher);
619 t!(fs::create_dir_all(&out_dir));
620 cfg.out_dir(out_dir);
622 for runtime in &runtimes {
623 cfg.build_target(&runtime.cmake_target);
627 t!(fs::write(&done_stamp, b""));
633 #[derive(Clone, Debug)]
634 pub struct SanitizerRuntime {
635 /// CMake target used to build the runtime.
636 pub cmake_target: String,
637 /// Path to the built runtime library.
639 /// Library filename that will be used rustc.
643 /// Returns sanitizers available on a given target.
644 fn supported_sanitizers(
646 target: Interned<String>,
648 ) -> Vec<SanitizerRuntime> {
649 let mut result = Vec::new();
651 "x86_64-apple-darwin" => {
652 for s in &["asan", "lsan", "tsan"] {
653 result.push(SanitizerRuntime {
654 cmake_target: format!("clang_rt.{}_osx_dynamic", s),
656 .join(&format!("build/lib/darwin/libclang_rt.{}_osx_dynamic.dylib", s)),
657 name: format!("librustc-{}_rt.{}.dylib", channel, s),
661 "x86_64-unknown-linux-gnu" => {
662 for s in &["asan", "lsan", "msan", "tsan"] {
663 result.push(SanitizerRuntime {
664 cmake_target: format!("clang_rt.{}-x86_64", s),
665 path: out_dir.join(&format!("build/lib/linux/libclang_rt.{}-x86_64.a", s)),
666 name: format!("librustc-{}_rt.{}.a", channel, s),
670 "x86_64-fuchsia" => {
672 result.push(SanitizerRuntime {
673 cmake_target: format!("clang_rt.{}-x86_64", s),
674 path: out_dir.join(&format!("build/lib/fuchsia/libclang_rt.{}-x86_64.a", s)),
675 name: format!("librustc-{}_rt.{}.a", channel, s),
679 "aarch64-fuchsia" => {
681 result.push(SanitizerRuntime {
682 cmake_target: format!("clang_rt.{}-aarch64", s),
683 path: out_dir.join(&format!("build/lib/fuchsia/libclang_rt.{}-aarch64.a", s)),
684 name: format!("librustc-{}_rt.{}.a", channel, s),