1 //! The AOT driver uses [`cranelift_object`] to write object files suitable for linking into a
2 //! standalone executable.
4 use std::path::PathBuf;
6 use rustc_codegen_ssa::back::linker::LinkerInfo;
7 use rustc_codegen_ssa::{CodegenResults, CompiledModule, CrateInfo, ModuleKind};
8 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
9 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
10 use rustc_middle::middle::cstore::EncodedMetadata;
11 use rustc_middle::mir::mono::{CodegenUnit, MonoItem};
12 use rustc_session::cgu_reuse_tracker::CguReuse;
13 use rustc_session::config::{DebugInfo, OutputType};
15 use cranelift_object::ObjectModule;
17 use crate::{prelude::*, BackendConfig};
19 fn new_module(tcx: TyCtxt<'_>, name: String) -> ObjectModule {
20 let module = crate::backend::make_module(tcx.sess, name);
21 assert_eq!(pointer_ty(tcx), module.target_config().pointer_type());
25 struct ModuleCodegenResult(CompiledModule, Option<(WorkProductId, WorkProduct)>);
27 impl<HCX> HashStable<HCX> for ModuleCodegenResult {
28 fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) {
38 debug: Option<DebugContext<'_>>,
39 unwind_context: UnwindContext<'_>,
40 ) -> ModuleCodegenResult {
41 let mut product = module.finish();
43 if let Some(mut debug) = debug {
44 debug.emit(&mut product);
47 unwind_context.emit(&mut product);
50 .output_filenames(LOCAL_CRATE)
51 .temp_path(OutputType::Object, Some(&name));
52 let obj = product.object.write().unwrap();
53 if let Err(err) = std::fs::write(&tmp_file, obj) {
55 .fatal(&format!("error writing object file: {}", err));
58 let work_product = if std::env::var("CG_CLIF_INCR_CACHE_DISABLED").is_ok() {
61 rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
64 &Some(tmp_file.clone()),
72 object: Some(tmp_file),
80 fn reuse_workproduct_for_cgu(
82 cgu: &CodegenUnit<'_>,
83 work_products: &mut FxHashMap<WorkProductId, WorkProduct>,
85 let incr_comp_session_dir = tcx.sess.incr_comp_session_dir();
86 let mut object = None;
87 let work_product = cgu.work_product(tcx);
88 if let Some(saved_file) = &work_product.saved_file {
90 .output_filenames(LOCAL_CRATE)
91 .temp_path(OutputType::Object, Some(&cgu.name().as_str()));
92 object = Some(obj_out.clone());
93 let source_file = rustc_incremental::in_incr_comp_dir(&incr_comp_session_dir, &saved_file);
94 if let Err(err) = rustc_fs_util::link_or_copy(&source_file, &obj_out) {
95 tcx.sess.err(&format!(
96 "unable to copy {} to {}: {}",
97 source_file.display(),
104 work_products.insert(cgu.work_product_id(), work_product);
107 name: cgu.name().to_string(),
108 kind: ModuleKind::Regular,
117 (backend_config, cgu_name): (BackendConfig, rustc_span::Symbol),
118 ) -> ModuleCodegenResult {
119 let cgu = tcx.codegen_unit(cgu_name);
120 let mono_items = cgu.items_in_deterministic_order(tcx);
122 let module = new_module(tcx, cgu_name.as_str().to_string());
124 let mut cx = crate::CodegenCx::new(
128 tcx.sess.opts.debuginfo != DebugInfo::None,
130 super::predefine_mono_items(&mut cx, &mono_items);
131 for (mono_item, (linkage, visibility)) in mono_items {
132 let linkage = crate::linkage::get_clif_linkage(mono_item, linkage, visibility);
134 MonoItem::Fn(inst) => {
135 cx.tcx.sess.time("codegen fn", || {
136 crate::base::codegen_fn(&mut cx, inst, linkage)
139 MonoItem::Static(def_id) => {
140 crate::constant::codegen_static(&mut cx.constants_cx, def_id)
142 MonoItem::GlobalAsm(hir_id) => {
143 let item = cx.tcx.hir().expect_item(hir_id);
144 if let rustc_hir::ItemKind::GlobalAsm(rustc_hir::GlobalAsm { asm }) = item.kind {
145 cx.global_asm.push_str(&*asm.as_str());
146 cx.global_asm.push_str("\n\n");
148 bug!("Expected GlobalAsm found {:?}", item);
153 let (mut module, global_asm, debug, mut unwind_context) =
154 tcx.sess.time("finalize CodegenCx", || cx.finalize());
155 crate::main_shim::maybe_create_entry_wrapper(tcx, &mut module, &mut unwind_context);
157 let codegen_result = emit_module(
159 cgu.name().as_str().to_string(),
166 codegen_global_asm(tcx, &cgu.name().as_str(), &global_asm);
171 pub(super) fn run_aot(
173 backend_config: BackendConfig,
174 metadata: EncodedMetadata,
175 need_metadata_module: bool,
176 ) -> Box<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>)> {
177 let mut work_products = FxHashMap::default();
179 let cgus = if tcx.sess.opts.output_types.should_codegen() {
180 tcx.collect_and_partition_mono_items(LOCAL_CRATE).1
182 // If only `--emit metadata` is used, we shouldn't perform any codegen.
183 // Also `tcx.collect_and_partition_mono_items` may panic in that case.
187 if tcx.dep_graph.is_fully_enabled() {
189 tcx.ensure().codegen_unit(cgu.name());
193 let modules = super::time(tcx, "codegen mono items", || {
196 let cgu_reuse = determine_cgu_reuse(tcx, cgu);
199 .set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
202 _ if std::env::var("CG_CLIF_INCR_CACHE_DISABLED").is_ok() => {}
204 CguReuse::PreLto => {
205 return reuse_workproduct_for_cgu(tcx, &*cgu, &mut work_products);
207 CguReuse::PostLto => unreachable!(),
210 let dep_node = cgu.codegen_dep_node(tcx);
211 let (ModuleCodegenResult(module, work_product), _) = tcx.dep_graph.with_task(
214 (backend_config, cgu.name()),
216 rustc_middle::dep_graph::hash_result,
219 if let Some((id, product)) = work_product {
220 work_products.insert(id, product);
228 tcx.sess.abort_if_errors();
230 let mut allocator_module = new_module(tcx, "allocator_shim".to_string());
231 let mut allocator_unwind_context = UnwindContext::new(tcx, allocator_module.isa(), true);
232 let created_alloc_shim =
233 crate::allocator::codegen(tcx, &mut allocator_module, &mut allocator_unwind_context);
235 let allocator_module = if created_alloc_shim {
236 let ModuleCodegenResult(module, work_product) = emit_module(
238 "allocator_shim".to_string(),
239 ModuleKind::Allocator,
242 allocator_unwind_context,
244 if let Some((id, product)) = work_product {
245 work_products.insert(id, product);
252 let metadata_module = if need_metadata_module {
253 let _timer = tcx.prof.generic_activity("codegen crate metadata");
254 let (metadata_cgu_name, tmp_file) = tcx.sess.time("write compressed metadata", || {
255 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
257 let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
258 let metadata_cgu_name = cgu_name_builder
259 .build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata"))
264 .output_filenames(LOCAL_CRATE)
265 .temp_path(OutputType::Metadata, Some(&metadata_cgu_name));
267 let obj = crate::backend::with_object(tcx.sess, &metadata_cgu_name, |object| {
268 crate::metadata::write_metadata(tcx, object);
271 if let Err(err) = std::fs::write(&tmp_file, obj) {
273 .fatal(&format!("error writing metadata object file: {}", err));
276 (metadata_cgu_name, tmp_file)
279 Some(CompiledModule {
280 name: metadata_cgu_name,
281 kind: ModuleKind::Metadata,
282 object: Some(tmp_file),
292 crate_name: tcx.crate_name(LOCAL_CRATE),
297 windows_subsystem: None, // Windows is not yet supported
298 linker_info: LinkerInfo::new(tcx),
299 crate_info: CrateInfo::new(tcx),
305 fn codegen_global_asm(tcx: TyCtxt<'_>, cgu_name: &str, global_asm: &str) {
307 use std::process::{Command, Stdio};
309 if global_asm.is_empty() {
313 if cfg!(not(feature = "inline_asm"))
314 || tcx.sess.target.is_like_osx
315 || tcx.sess.target.is_like_windows
317 if global_asm.contains("__rust_probestack") {
321 // FIXME fix linker error on macOS
322 if cfg!(not(feature = "inline_asm")) {
324 "asm! and global_asm! support is disabled while compiling rustc_codegen_cranelift",
328 .fatal("asm! and global_asm! are not yet supported on macOS and Windows");
332 let assembler = crate::toolchain::get_toolchain_binary(tcx.sess, "as");
333 let linker = crate::toolchain::get_toolchain_binary(tcx.sess, "ld");
335 // Remove all LLVM style comments
336 let global_asm = global_asm
339 if let Some(index) = line.find("//") {
348 let output_object_file = tcx
349 .output_filenames(LOCAL_CRATE)
350 .temp_path(OutputType::Object, Some(cgu_name));
352 // Assemble `global_asm`
353 let global_asm_object_file = add_file_stem_postfix(output_object_file.clone(), ".asm");
354 let mut child = Command::new(assembler)
356 .arg(&global_asm_object_file)
357 .stdin(Stdio::piped())
359 .expect("Failed to spawn `as`.");
364 .write_all(global_asm.as_bytes())
366 let status = child.wait().expect("Failed to wait for `as`.");
367 if !status.success() {
369 .fatal(&format!("Failed to assemble `{}`", global_asm));
372 // Link the global asm and main object file together
373 let main_object_file = add_file_stem_postfix(output_object_file.clone(), ".main");
374 std::fs::rename(&output_object_file, &main_object_file).unwrap();
375 let status = Command::new(linker)
376 .arg("-r") // Create a new object file
378 .arg(output_object_file)
379 .arg(&main_object_file)
380 .arg(&global_asm_object_file)
383 if !status.success() {
384 tcx.sess.fatal(&format!(
385 "Failed to link `{}` and `{}` together",
386 main_object_file.display(),
387 global_asm_object_file.display(),
391 std::fs::remove_file(global_asm_object_file).unwrap();
392 std::fs::remove_file(main_object_file).unwrap();
395 fn add_file_stem_postfix(mut path: PathBuf, postfix: &str) -> PathBuf {
396 let mut new_filename = path.file_stem().unwrap().to_owned();
397 new_filename.push(postfix);
398 if let Some(extension) = path.extension() {
399 new_filename.push(".");
400 new_filename.push(extension);
402 path.set_file_name(new_filename);
406 // Adapted from https://github.com/rust-lang/rust/blob/303d8aff6092709edd4dbd35b1c88e9aa40bf6d8/src/librustc_codegen_ssa/base.rs#L922-L953
407 fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
408 if !tcx.dep_graph.is_fully_enabled() {
412 let work_product_id = &cgu.work_product_id();
415 .previous_work_product(work_product_id)
418 // We don't have anything cached for this CGU. This can happen
419 // if the CGU did not exist in the previous session.
423 // Try to mark the CGU as green. If it we can do so, it means that nothing
424 // affecting the LLVM module has changed and we can re-use a cached version.
425 // If we compile with any kind of LTO, this means we can re-use the bitcode
426 // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
427 // know that later). If we are not doing LTO, there is only one optimized
428 // version of each module, so we re-use that.
429 let dep_node = cgu.codegen_dep_node(tcx);
431 !tcx.dep_graph.dep_node_exists(&dep_node),
432 "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
436 if tcx.dep_graph.try_mark_green(tcx, &dep_node).is_some() {