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_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
7 use rustc_codegen_ssa::back::metadata::create_compressed_metadata_file;
8 use rustc_codegen_ssa::{CodegenResults, CompiledModule, CrateInfo, ModuleKind};
9 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
10 use rustc_metadata::EncodedMetadata;
11 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
12 use rustc_middle::mir::mono::{CodegenUnit, MonoItem};
13 use rustc_session::cgu_reuse_tracker::CguReuse;
14 use rustc_session::config::{DebugInfo, OutputType};
15 use rustc_session::Session;
17 use cranelift_codegen::isa::TargetIsa;
18 use cranelift_object::{ObjectBuilder, ObjectModule};
20 use crate::{prelude::*, BackendConfig};
22 struct ModuleCodegenResult(CompiledModule, Option<(WorkProductId, WorkProduct)>);
24 impl<HCX> HashStable<HCX> for ModuleCodegenResult {
25 fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) {
30 fn make_module(sess: &Session, isa: Box<dyn TargetIsa>, name: String) -> ObjectModule {
32 ObjectBuilder::new(isa, name + ".o", cranelift_module::default_libcall_names()).unwrap();
33 // Unlike cg_llvm, cg_clif defaults to disabling -Zfunction-sections. For cg_llvm binary size
34 // is important, while cg_clif cares more about compilation times. Enabling -Zfunction-sections
35 // can easily double the amount of time necessary to perform linking.
36 builder.per_function_section(sess.opts.debugging_opts.function_sections.unwrap_or(false));
37 ObjectModule::new(builder)
42 backend_config: &BackendConfig,
46 debug: Option<DebugContext<'_>>,
47 unwind_context: UnwindContext,
48 ) -> ModuleCodegenResult {
49 let mut product = module.finish();
51 if let Some(mut debug) = debug {
52 debug.emit(&mut product);
55 unwind_context.emit(&mut product);
57 let tmp_file = tcx.output_filenames(()).temp_path(OutputType::Object, Some(&name));
58 let obj = product.object.write().unwrap();
59 if let Err(err) = std::fs::write(&tmp_file, obj) {
60 tcx.sess.fatal(&format!("error writing object file: {}", err));
63 let work_product = if backend_config.disable_incr_cache {
66 rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
69 &Some(tmp_file.clone()),
74 CompiledModule { name, kind, object: Some(tmp_file), dwarf_object: None, bytecode: None },
79 fn reuse_workproduct_for_cgu(
81 cgu: &CodegenUnit<'_>,
82 work_products: &mut FxHashMap<WorkProductId, WorkProduct>,
84 let mut object = None;
85 let work_product = cgu.work_product(tcx);
86 if let Some(saved_file) = &work_product.saved_file {
88 tcx.output_filenames(()).temp_path(OutputType::Object, Some(&cgu.name().as_str()));
89 object = Some(obj_out.clone());
90 let source_file = rustc_incremental::in_incr_comp_dir_sess(&tcx.sess, &saved_file);
91 if let Err(err) = rustc_fs_util::link_or_copy(&source_file, &obj_out) {
92 tcx.sess.err(&format!(
93 "unable to copy {} to {}: {}",
94 source_file.display(),
101 work_products.insert(cgu.work_product_id(), work_product);
104 name: cgu.name().to_string(),
105 kind: ModuleKind::Regular,
114 (backend_config, cgu_name): (BackendConfig, rustc_span::Symbol),
115 ) -> ModuleCodegenResult {
116 let cgu = tcx.codegen_unit(cgu_name);
117 let mono_items = cgu.items_in_deterministic_order(tcx);
119 let isa = crate::build_isa(tcx.sess, &backend_config);
120 let mut module = make_module(tcx.sess, isa, cgu_name.as_str().to_string());
122 let mut cx = crate::CodegenCx::new(
124 backend_config.clone(),
126 tcx.sess.opts.debuginfo != DebugInfo::None,
129 super::predefine_mono_items(tcx, &mut module, &mono_items);
130 for (mono_item, _) in mono_items {
132 MonoItem::Fn(inst) => {
135 .time("codegen fn", || crate::base::codegen_fn(&mut cx, &mut module, inst));
137 MonoItem::Static(def_id) => crate::constant::codegen_static(tcx, &mut module, def_id),
138 MonoItem::GlobalAsm(item_id) => {
139 let item = cx.tcx.hir().item(item_id);
140 if let rustc_hir::ItemKind::GlobalAsm(asm) = item.kind {
141 if !asm.options.contains(InlineAsmOptions::ATT_SYNTAX) {
142 cx.global_asm.push_str("\n.intel_syntax noprefix\n");
144 cx.global_asm.push_str("\n.att_syntax\n");
146 for piece in asm.template {
148 InlineAsmTemplatePiece::String(ref s) => cx.global_asm.push_str(s),
149 InlineAsmTemplatePiece::Placeholder { .. } => todo!(),
152 cx.global_asm.push_str("\n.att_syntax\n\n");
154 bug!("Expected GlobalAsm found {:?}", item);
159 crate::main_shim::maybe_create_entry_wrapper(
162 &mut cx.unwind_context,
167 let debug_context = cx.debug_context;
168 let unwind_context = cx.unwind_context;
169 let codegen_result = tcx.sess.time("write object file", || {
173 cgu.name().as_str().to_string(),
181 codegen_global_asm(tcx, &cgu.name().as_str(), &cx.global_asm);
186 pub(crate) fn run_aot(
188 backend_config: BackendConfig,
189 metadata: EncodedMetadata,
190 need_metadata_module: bool,
191 ) -> Box<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>)> {
192 let mut work_products = FxHashMap::default();
194 let cgus = if tcx.sess.opts.output_types.should_codegen() {
195 tcx.collect_and_partition_mono_items(()).1
197 // If only `--emit metadata` is used, we shouldn't perform any codegen.
198 // Also `tcx.collect_and_partition_mono_items` may panic in that case.
202 if tcx.dep_graph.is_fully_enabled() {
204 tcx.ensure().codegen_unit(cgu.name());
208 let modules = super::time(tcx, backend_config.display_cg_time, "codegen mono items", || {
211 let cgu_reuse = determine_cgu_reuse(tcx, cgu);
212 tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
215 _ if backend_config.disable_incr_cache => {}
217 CguReuse::PreLto => {
218 return reuse_workproduct_for_cgu(tcx, &*cgu, &mut work_products);
220 CguReuse::PostLto => unreachable!(),
223 let dep_node = cgu.codegen_dep_node(tcx);
224 let (ModuleCodegenResult(module, work_product), _) = tcx.dep_graph.with_task(
227 (backend_config.clone(), cgu.name()),
229 Some(rustc_middle::dep_graph::hash_result),
232 if let Some((id, product)) = work_product {
233 work_products.insert(id, product);
241 tcx.sess.abort_if_errors();
243 let isa = crate::build_isa(tcx.sess, &backend_config);
244 let mut allocator_module = make_module(tcx.sess, isa, "allocator_shim".to_string());
245 assert_eq!(pointer_ty(tcx), allocator_module.target_config().pointer_type());
246 let mut allocator_unwind_context = UnwindContext::new(tcx, allocator_module.isa(), true);
247 let created_alloc_shim =
248 crate::allocator::codegen(tcx, &mut allocator_module, &mut allocator_unwind_context);
250 let allocator_module = if created_alloc_shim {
251 let ModuleCodegenResult(module, work_product) = emit_module(
254 "allocator_shim".to_string(),
255 ModuleKind::Allocator,
258 allocator_unwind_context,
260 if let Some((id, product)) = work_product {
261 work_products.insert(id, product);
268 let metadata_module = if need_metadata_module {
269 let _timer = tcx.prof.generic_activity("codegen crate metadata");
270 let (metadata_cgu_name, tmp_file) = tcx.sess.time("write compressed metadata", || {
271 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
273 let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
274 let metadata_cgu_name = cgu_name_builder
275 .build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata"))
280 tcx.output_filenames(()).temp_path(OutputType::Metadata, Some(&metadata_cgu_name));
282 let symbol_name = rustc_middle::middle::exported_symbols::metadata_symbol_name(tcx);
283 let obj = create_compressed_metadata_file(tcx.sess, &metadata, &symbol_name);
285 if let Err(err) = std::fs::write(&tmp_file, obj) {
286 tcx.sess.fatal(&format!("error writing metadata object file: {}", err));
289 (metadata_cgu_name, tmp_file)
292 Some(CompiledModule {
293 name: metadata_cgu_name,
294 kind: ModuleKind::Metadata,
295 object: Some(tmp_file),
303 // FIXME handle `-Ctarget-cpu=native`
305 tcx.sess.opts.cg.target_cpu.as_ref().unwrap_or(&tcx.sess.target.cpu).to_owned();
312 crate_info: CrateInfo::new(tcx, target_cpu),
318 fn codegen_global_asm(tcx: TyCtxt<'_>, cgu_name: &str, global_asm: &str) {
320 use std::process::{Command, Stdio};
322 if global_asm.is_empty() {
326 if cfg!(not(feature = "inline_asm"))
327 || tcx.sess.target.is_like_osx
328 || tcx.sess.target.is_like_windows
330 if global_asm.contains("__rust_probestack") {
334 // FIXME fix linker error on macOS
335 if cfg!(not(feature = "inline_asm")) {
337 "asm! and global_asm! support is disabled while compiling rustc_codegen_cranelift",
340 tcx.sess.fatal("asm! and global_asm! are not yet supported on macOS and Windows");
344 let assembler = crate::toolchain::get_toolchain_binary(tcx.sess, "as");
345 let linker = crate::toolchain::get_toolchain_binary(tcx.sess, "ld");
347 // Remove all LLVM style comments
348 let global_asm = global_asm
350 .map(|line| if let Some(index) = line.find("//") { &line[0..index] } else { line })
354 let output_object_file = tcx.output_filenames(()).temp_path(OutputType::Object, Some(cgu_name));
356 // Assemble `global_asm`
357 let global_asm_object_file = add_file_stem_postfix(output_object_file.clone(), ".asm");
358 let mut child = Command::new(assembler)
360 .arg(&global_asm_object_file)
361 .stdin(Stdio::piped())
363 .expect("Failed to spawn `as`.");
364 child.stdin.take().unwrap().write_all(global_asm.as_bytes()).unwrap();
365 let status = child.wait().expect("Failed to wait for `as`.");
366 if !status.success() {
367 tcx.sess.fatal(&format!("Failed to assemble `{}`", global_asm));
370 // Link the global asm and main object file together
371 let main_object_file = add_file_stem_postfix(output_object_file.clone(), ".main");
372 std::fs::rename(&output_object_file, &main_object_file).unwrap();
373 let status = Command::new(linker)
374 .arg("-r") // Create a new object file
376 .arg(output_object_file)
377 .arg(&main_object_file)
378 .arg(&global_asm_object_file)
381 if !status.success() {
382 tcx.sess.fatal(&format!(
383 "Failed to link `{}` and `{}` together",
384 main_object_file.display(),
385 global_asm_object_file.display(),
389 std::fs::remove_file(global_asm_object_file).unwrap();
390 std::fs::remove_file(main_object_file).unwrap();
393 fn add_file_stem_postfix(mut path: PathBuf, postfix: &str) -> PathBuf {
394 let mut new_filename = path.file_stem().unwrap().to_owned();
395 new_filename.push(postfix);
396 if let Some(extension) = path.extension() {
397 new_filename.push(".");
398 new_filename.push(extension);
400 path.set_file_name(new_filename);
404 // Adapted from https://github.com/rust-lang/rust/blob/303d8aff6092709edd4dbd35b1c88e9aa40bf6d8/src/librustc_codegen_ssa/base.rs#L922-L953
405 fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
406 if !tcx.dep_graph.is_fully_enabled() {
410 let work_product_id = &cgu.work_product_id();
411 if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
412 // We don't have anything cached for this CGU. This can happen
413 // if the CGU did not exist in the previous session.
417 // Try to mark the CGU as green. If it we can do so, it means that nothing
418 // affecting the LLVM module has changed and we can re-use a cached version.
419 // If we compile with any kind of LTO, this means we can re-use the bitcode
420 // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
421 // know that later). If we are not doing LTO, there is only one optimized
422 // version of each module, so we re-use that.
423 let dep_node = cgu.codegen_dep_node(tcx);
425 !tcx.dep_graph.dep_node_exists(&dep_node),
426 "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
430 if tcx.try_mark_green(&dep_node) { CguReuse::PreLto } else { CguReuse::No }