1 //! The AOT driver uses [`cranelift_object`] to write object files suitable for linking into a
2 //! standalone executable.
5 use std::path::PathBuf;
7 use std::thread::JoinHandle;
9 use rustc_codegen_ssa::back::metadata::create_compressed_metadata_file;
10 use rustc_codegen_ssa::{CodegenResults, CompiledModule, CrateInfo, ModuleKind};
11 use rustc_data_structures::profiling::SelfProfilerRef;
12 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
13 use rustc_metadata::EncodedMetadata;
14 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
15 use rustc_middle::mir::mono::{CodegenUnit, MonoItem};
16 use rustc_session::cgu_reuse_tracker::CguReuse;
17 use rustc_session::config::{DebugInfo, OutputFilenames, OutputType};
18 use rustc_session::Session;
20 use cranelift_object::{ObjectBuilder, ObjectModule};
22 use crate::concurrency_limiter::{ConcurrencyLimiter, ConcurrencyLimiterToken};
23 use crate::global_asm::GlobalAsmConfig;
24 use crate::{prelude::*, BackendConfig};
26 struct ModuleCodegenResult {
27 module_regular: CompiledModule,
28 module_global_asm: Option<CompiledModule>,
29 existing_work_product: Option<(WorkProductId, WorkProduct)>,
32 enum OngoingModuleCodegen {
33 Sync(Result<ModuleCodegenResult, String>),
34 Async(JoinHandle<Result<ModuleCodegenResult, String>>),
37 impl<HCX> HashStable<HCX> for OngoingModuleCodegen {
38 fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) {
43 pub(crate) struct OngoingCodegen {
44 modules: Vec<OngoingModuleCodegen>,
45 allocator_module: Option<CompiledModule>,
46 metadata_module: Option<CompiledModule>,
47 metadata: EncodedMetadata,
48 crate_info: CrateInfo,
49 concurrency_limiter: ConcurrencyLimiter,
56 backend_config: &BackendConfig,
57 ) -> (CodegenResults, FxHashMap<WorkProductId, WorkProduct>) {
58 let mut work_products = FxHashMap::default();
59 let mut modules = vec![];
61 for module_codegen in self.modules {
62 let module_codegen_result = match module_codegen {
63 OngoingModuleCodegen::Sync(module_codegen_result) => module_codegen_result,
64 OngoingModuleCodegen::Async(join_handle) => match join_handle.join() {
65 Ok(module_codegen_result) => module_codegen_result,
66 Err(panic) => std::panic::resume_unwind(panic),
70 let module_codegen_result = match module_codegen_result {
71 Ok(module_codegen_result) => module_codegen_result,
72 Err(err) => sess.fatal(&err),
74 let ModuleCodegenResult { module_regular, module_global_asm, existing_work_product } =
75 module_codegen_result;
77 if let Some((work_product_id, work_product)) = existing_work_product {
78 work_products.insert(work_product_id, work_product);
80 let work_product = if backend_config.disable_incr_cache {
82 } else if let Some(module_global_asm) = &module_global_asm {
83 rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
87 ("o", &module_regular.object.as_ref().unwrap()),
88 ("asm.o", &module_global_asm.object.as_ref().unwrap()),
92 rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
95 &[("o", &module_regular.object.as_ref().unwrap())],
98 if let Some((work_product_id, work_product)) = work_product {
99 work_products.insert(work_product_id, work_product);
103 modules.push(module_regular);
104 if let Some(module_global_asm) = module_global_asm {
105 modules.push(module_global_asm);
109 drop(self.concurrency_limiter);
114 allocator_module: self.allocator_module,
115 metadata_module: self.metadata_module,
116 metadata: self.metadata,
117 crate_info: self.crate_info,
124 fn make_module(sess: &Session, backend_config: &BackendConfig, name: String) -> ObjectModule {
125 let isa = crate::build_isa(sess, backend_config);
128 ObjectBuilder::new(isa, name + ".o", cranelift_module::default_libcall_names()).unwrap();
129 // Unlike cg_llvm, cg_clif defaults to disabling -Zfunction-sections. For cg_llvm binary size
130 // is important, while cg_clif cares more about compilation times. Enabling -Zfunction-sections
131 // can easily double the amount of time necessary to perform linking.
132 builder.per_function_section(sess.opts.unstable_opts.function_sections.unwrap_or(false));
133 ObjectModule::new(builder)
137 output_filenames: &OutputFilenames,
138 prof: &SelfProfilerRef,
140 module: ObjectModule,
141 debug: Option<DebugContext>,
142 unwind_context: UnwindContext,
143 global_asm_object_file: Option<PathBuf>,
144 ) -> Result<ModuleCodegenResult, String> {
145 let mut product = module.finish();
147 if let Some(mut debug) = debug {
148 debug.emit(&mut product);
151 unwind_context.emit(&mut product);
154 emit_module(output_filenames, prof, product.object, ModuleKind::Regular, name.clone())?;
156 Ok(ModuleCodegenResult {
158 module_global_asm: global_asm_object_file.map(|global_asm_object_file| CompiledModule {
159 name: format!("{name}.asm"),
160 kind: ModuleKind::Regular,
161 object: Some(global_asm_object_file),
165 existing_work_product: None,
170 output_filenames: &OutputFilenames,
171 prof: &SelfProfilerRef,
172 object: cranelift_object::object::write::Object<'_>,
175 ) -> Result<CompiledModule, String> {
176 let tmp_file = output_filenames.temp_path(OutputType::Object, Some(&name));
177 let mut file = match File::create(&tmp_file) {
179 Err(err) => return Err(format!("error creating object file: {}", err)),
182 if let Err(err) = object.write_stream(&mut file) {
183 return Err(format!("error writing object file: {}", err));
186 prof.artifact_size("object_file", &*name, file.metadata().unwrap().len());
188 Ok(CompiledModule { name, kind, object: Some(tmp_file), dwarf_object: None, bytecode: None })
191 fn reuse_workproduct_for_cgu(
193 cgu: &CodegenUnit<'_>,
194 ) -> Result<ModuleCodegenResult, String> {
195 let work_product = cgu.previous_work_product(tcx);
196 let obj_out_regular =
197 tcx.output_filenames(()).temp_path(OutputType::Object, Some(cgu.name().as_str()));
198 let source_file_regular = rustc_incremental::in_incr_comp_dir_sess(
200 &work_product.saved_files.get("o").expect("no saved object file in work product"),
203 if let Err(err) = rustc_fs_util::link_or_copy(&source_file_regular, &obj_out_regular) {
205 "unable to copy {} to {}: {}",
206 source_file_regular.display(),
207 obj_out_regular.display(),
211 let obj_out_global_asm =
212 crate::global_asm::add_file_stem_postfix(obj_out_regular.clone(), ".asm");
213 let has_global_asm = if let Some(asm_o) = work_product.saved_files.get("asm.o") {
214 let source_file_global_asm = rustc_incremental::in_incr_comp_dir_sess(&tcx.sess, asm_o);
215 if let Err(err) = rustc_fs_util::link_or_copy(&source_file_global_asm, &obj_out_global_asm)
218 "unable to copy {} to {}: {}",
219 source_file_regular.display(),
220 obj_out_regular.display(),
229 Ok(ModuleCodegenResult {
230 module_regular: CompiledModule {
231 name: cgu.name().to_string(),
232 kind: ModuleKind::Regular,
233 object: Some(obj_out_regular),
237 module_global_asm: if has_global_asm {
238 Some(CompiledModule {
239 name: cgu.name().to_string(),
240 kind: ModuleKind::Regular,
241 object: Some(obj_out_global_asm),
248 existing_work_product: Some((cgu.work_product_id(), work_product)),
254 (backend_config, global_asm_config, cgu_name, token): (
256 Arc<GlobalAsmConfig>,
258 ConcurrencyLimiterToken,
260 ) -> OngoingModuleCodegen {
261 let (cgu_name, mut cx, mut module, codegened_functions) = tcx.sess.time("codegen cgu", || {
262 let cgu = tcx.codegen_unit(cgu_name);
263 let mono_items = cgu.items_in_deterministic_order(tcx);
265 let mut module = make_module(tcx.sess, &backend_config, cgu_name.as_str().to_string());
267 let mut cx = crate::CodegenCx::new(
269 backend_config.clone(),
271 tcx.sess.opts.debuginfo != DebugInfo::None,
274 super::predefine_mono_items(tcx, &mut module, &mono_items);
275 let mut codegened_functions = vec![];
276 for (mono_item, _) in mono_items {
278 MonoItem::Fn(inst) => {
279 tcx.sess.time("codegen fn", || {
280 let codegened_function = crate::base::codegen_fn(
287 codegened_functions.push(codegened_function);
290 MonoItem::Static(def_id) => {
291 crate::constant::codegen_static(tcx, &mut module, def_id)
293 MonoItem::GlobalAsm(item_id) => {
294 crate::global_asm::codegen_global_asm_item(tcx, &mut cx.global_asm, item_id);
298 crate::main_shim::maybe_create_entry_wrapper(
301 &mut cx.unwind_context,
306 let cgu_name = cgu.name().as_str().to_owned();
308 (cgu_name, cx, module, codegened_functions)
311 OngoingModuleCodegen::Async(std::thread::spawn(move || {
312 cx.profiler.clone().verbose_generic_activity("compile functions").run(|| {
313 let mut cached_context = Context::new();
314 for codegened_func in codegened_functions {
315 crate::base::compile_fn(&mut cx, &mut cached_context, &mut module, codegened_func);
319 let global_asm_object_file =
320 cx.profiler.verbose_generic_activity("compile assembly").run(|| {
321 crate::global_asm::compile_global_asm(&global_asm_config, &cgu_name, &cx.global_asm)
324 let codegen_result = cx.profiler.verbose_generic_activity("write object file").run(|| {
326 &global_asm_config.output_filenames,
332 global_asm_object_file,
335 std::mem::drop(token);
340 pub(crate) fn run_aot(
342 backend_config: BackendConfig,
343 metadata: EncodedMetadata,
344 need_metadata_module: bool,
345 ) -> Box<OngoingCodegen> {
346 let cgus = if tcx.sess.opts.output_types.should_codegen() {
347 tcx.collect_and_partition_mono_items(()).1
349 // If only `--emit metadata` is used, we shouldn't perform any codegen.
350 // Also `tcx.collect_and_partition_mono_items` may panic in that case.
354 if tcx.dep_graph.is_fully_enabled() {
356 tcx.ensure().codegen_unit(cgu.name());
360 let global_asm_config = Arc::new(crate::global_asm::GlobalAsmConfig::new(tcx));
362 let mut concurrency_limiter = ConcurrencyLimiter::new(tcx.sess, cgus.len());
364 let modules = super::time(tcx, backend_config.display_cg_time, "codegen mono items", || {
367 let cgu_reuse = if backend_config.disable_incr_cache {
370 determine_cgu_reuse(tcx, cgu)
372 tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);
376 let dep_node = cgu.codegen_dep_node(tcx);
382 backend_config.clone(),
383 global_asm_config.clone(),
385 concurrency_limiter.acquire(),
388 Some(rustc_middle::dep_graph::hash_result),
392 CguReuse::PreLto => unreachable!(),
393 CguReuse::PostLto => {
394 concurrency_limiter.job_already_done();
395 OngoingModuleCodegen::Sync(reuse_workproduct_for_cgu(tcx, &*cgu))
402 tcx.sess.abort_if_errors();
404 let mut allocator_module = make_module(tcx.sess, &backend_config, "allocator_shim".to_string());
405 let mut allocator_unwind_context = UnwindContext::new(allocator_module.isa(), true);
406 let created_alloc_shim =
407 crate::allocator::codegen(tcx, &mut allocator_module, &mut allocator_unwind_context);
409 let allocator_module = if created_alloc_shim {
410 let mut product = allocator_module.finish();
411 allocator_unwind_context.emit(&mut product);
414 tcx.output_filenames(()),
417 ModuleKind::Allocator,
418 "allocator_shim".to_owned(),
420 Ok(allocator_module) => Some(allocator_module),
421 Err(err) => tcx.sess.fatal(err),
427 let metadata_module = if need_metadata_module {
428 let _timer = tcx.prof.generic_activity("codegen crate metadata");
429 let (metadata_cgu_name, tmp_file) = tcx.sess.time("write compressed metadata", || {
430 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
432 let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
433 let metadata_cgu_name = cgu_name_builder
434 .build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata"))
439 tcx.output_filenames(()).temp_path(OutputType::Metadata, Some(&metadata_cgu_name));
441 let symbol_name = rustc_middle::middle::exported_symbols::metadata_symbol_name(tcx);
442 let obj = create_compressed_metadata_file(tcx.sess, &metadata, &symbol_name);
444 if let Err(err) = std::fs::write(&tmp_file, obj) {
445 tcx.sess.fatal(&format!("error writing metadata object file: {}", err));
448 (metadata_cgu_name, tmp_file)
451 Some(CompiledModule {
452 name: metadata_cgu_name,
453 kind: ModuleKind::Metadata,
454 object: Some(tmp_file),
462 // FIXME handle `-Ctarget-cpu=native`
463 let target_cpu = match tcx.sess.opts.cg.target_cpu {
464 Some(ref name) => name,
465 None => tcx.sess.target.cpu.as_ref(),
469 Box::new(OngoingCodegen {
474 crate_info: CrateInfo::new(tcx, target_cpu),
479 // Adapted from https://github.com/rust-lang/rust/blob/303d8aff6092709edd4dbd35b1c88e9aa40bf6d8/src/librustc_codegen_ssa/base.rs#L922-L953
480 fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
481 if !tcx.dep_graph.is_fully_enabled() {
485 let work_product_id = &cgu.work_product_id();
486 if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
487 // We don't have anything cached for this CGU. This can happen
488 // if the CGU did not exist in the previous session.
492 // Try to mark the CGU as green. If it we can do so, it means that nothing
493 // affecting the LLVM module has changed and we can re-use a cached version.
494 // If we compile with any kind of LTO, this means we can re-use the bitcode
495 // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
496 // know that later). If we are not doing LTO, there is only one optimized
497 // version of each module, so we re-use that.
498 let dep_node = cgu.codegen_dep_node(tcx);
500 !tcx.dep_graph.dep_node_exists(&dep_node),
501 "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
505 if tcx.try_mark_green(&dep_node) { CguReuse::PostLto } else { CguReuse::No }