1 //! Codegen the completed AST to the LLVM IR.
3 //! Some functions here, such as codegen_block and codegen_expr, return a value --
4 //! the result of the codegen to LLVM -- while others, such as codegen_fn
5 //! and mono_item, are called only for the side effect of adding a
6 //! particular definition to the LLVM IR output we're producing.
8 //! Hopefully useful general knowledge about codegen:
10 //! * There's no way to find out the `Ty` type of a Value. Doing so
11 //! would be "trying to get the eggs out of an omelette" (credit:
12 //! pcwalton). You can, instead, find out its `llvm::Type` by calling `val_ty`,
13 //! but one `llvm::Type` corresponds to many `Ty`s; for instance, `tup(int, int,
14 //! int)` and `rec(x=int, y=int, z=int)` will have the same `llvm::Type`.
16 use crate::{ModuleCodegen, ModuleKind, CachedModuleCodegen};
18 use rustc::dep_graph::cgu_reuse_tracker::CguReuse;
19 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
20 use rustc::middle::cstore::EncodedMetadata;
21 use rustc::middle::lang_items::StartFnLangItem;
22 use rustc::middle::weak_lang_items;
23 use rustc::mir::mono::{Stats, CodegenUnitNameBuilder};
24 use rustc::ty::{self, Ty, TyCtxt};
25 use rustc::ty::layout::{self, Align, TyLayout, LayoutOf, VariantIdx, HasTyCtxt};
26 use rustc::ty::query::Providers;
27 use rustc::middle::cstore::{self, LinkagePreference};
28 use rustc::util::common::{time, print_time_passes_entry};
29 use rustc::session::config::{self, EntryFnType, Lto};
30 use rustc::session::Session;
31 use rustc_mir::monomorphize::item::DefPathBasedNames;
32 use rustc_mir::monomorphize::Instance;
33 use rustc_mir::monomorphize::partitioning::{CodegenUnit, CodegenUnitExt};
34 use rustc::util::nodemap::FxHashMap;
35 use rustc_data_structures::indexed_vec::Idx;
36 use rustc_data_structures::sync::Lrc;
37 use rustc_codegen_utils::{symbol_names_test, check_for_rustc_errors_attr};
38 use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
39 use crate::mir::place::PlaceRef;
40 use crate::back::write::{OngoingCodegen, start_async_codegen, submit_pre_lto_module_to_llvm,
41 submit_post_lto_module_to_llvm};
42 use crate::{MemFlags, CrateInfo};
44 use crate::common::{RealPredicate, TypeKind, IntPredicate};
47 use crate::mono_item::MonoItem;
53 use std::ops::{Deref, DerefMut};
54 use std::time::{Instant, Duration};
60 use crate::mir::operand::OperandValue;
62 use std::marker::PhantomData;
64 pub struct StatRecorder<'a, 'tcx, Cx: 'a + CodegenMethods<'tcx>> {
68 _marker: PhantomData<&'tcx ()>,
71 impl<'a, 'tcx, Cx: CodegenMethods<'tcx>> StatRecorder<'a, 'tcx, Cx> {
72 pub fn new(cx: &'a Cx, name: String) -> Self {
73 let istart = cx.stats().borrow().n_llvm_insns;
83 impl<'a, 'tcx, Cx: CodegenMethods<'tcx>> Drop for StatRecorder<'a, 'tcx, Cx> {
85 if self.cx.sess().codegen_stats() {
86 let mut stats = self.cx.stats().borrow_mut();
87 let iend = stats.n_llvm_insns;
88 stats.fn_stats.push((self.name.take().unwrap(), iend - self.istart));
90 // Reset LLVM insn count to avoid compound costs.
91 stats.n_llvm_insns = self.istart;
96 pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind,
100 hir::BinOpKind::Eq => IntPredicate::IntEQ,
101 hir::BinOpKind::Ne => IntPredicate::IntNE,
102 hir::BinOpKind::Lt => if signed { IntPredicate::IntSLT } else { IntPredicate::IntULT },
103 hir::BinOpKind::Le => if signed { IntPredicate::IntSLE } else { IntPredicate::IntULE },
104 hir::BinOpKind::Gt => if signed { IntPredicate::IntSGT } else { IntPredicate::IntUGT },
105 hir::BinOpKind::Ge => if signed { IntPredicate::IntSGE } else { IntPredicate::IntUGE },
107 bug!("comparison_op_to_icmp_predicate: expected comparison operator, \
114 pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> RealPredicate {
116 hir::BinOpKind::Eq => RealPredicate::RealOEQ,
117 hir::BinOpKind::Ne => RealPredicate::RealUNE,
118 hir::BinOpKind::Lt => RealPredicate::RealOLT,
119 hir::BinOpKind::Le => RealPredicate::RealOLE,
120 hir::BinOpKind::Gt => RealPredicate::RealOGT,
121 hir::BinOpKind::Ge => RealPredicate::RealOGE,
123 bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \
130 pub fn compare_simd_types<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
138 let signed = match t.sty {
140 let cmp = bin_op_to_fcmp_predicate(op);
141 let cmp = bx.fcmp(cmp, lhs, rhs);
142 return bx.sext(cmp, ret_ty);
144 ty::Uint(_) => false,
146 _ => bug!("compare_simd_types: invalid SIMD type"),
149 let cmp = bin_op_to_icmp_predicate(op, signed);
150 let cmp = bx.icmp(cmp, lhs, rhs);
151 // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
152 // to get the correctly sized type. This will compile to a single instruction
153 // once the IR is converted to assembly if the SIMD instruction is supported
154 // by the target architecture.
158 /// Retrieves the information we are losing (making dynamic) in an unsizing
161 /// The `old_info` argument is a bit funny. It is intended for use
162 /// in an upcast, where the new vtable for an object will be derived
163 /// from the old one.
164 pub fn unsized_info<'tcx, Cx: CodegenMethods<'tcx>>(
168 old_info: Option<Cx::Value>,
170 let (source, target) = cx.tcx().struct_lockstep_tails(source, target);
171 match (&source.sty, &target.sty) {
172 (&ty::Array(_, len), &ty::Slice(_)) => {
173 cx.const_usize(len.unwrap_usize(cx.tcx()))
175 (&ty::Dynamic(..), &ty::Dynamic(..)) => {
176 // For now, upcasts are limited to changes in marker
177 // traits, and hence never actually require an actual
178 // change to the vtable.
179 old_info.expect("unsized_info: missing old info for trait upcast")
181 (_, &ty::Dynamic(ref data, ..)) => {
182 let vtable_ptr = cx.layout_of(cx.tcx().mk_mut_ptr(target))
183 .field(cx, FAT_PTR_EXTRA);
184 cx.const_ptrcast(meth::get_vtable(cx, source, data.principal()),
185 cx.backend_type(vtable_ptr))
187 _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}",
193 /// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer.
194 pub fn unsize_thin_ptr<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
199 ) -> (Bx::Value, Bx::Value) {
200 debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
201 match (&src_ty.sty, &dst_ty.sty) {
205 &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) |
206 (&ty::RawPtr(ty::TypeAndMut { ty: a, .. }),
207 &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => {
208 assert!(bx.cx().type_is_sized(a));
209 let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
210 (bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
212 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
213 let (a, b) = (src_ty.boxed_ty(), dst_ty.boxed_ty());
214 assert!(bx.cx().type_is_sized(a));
215 let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
216 (bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
218 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
219 assert_eq!(def_a, def_b);
221 let src_layout = bx.cx().layout_of(src_ty);
222 let dst_layout = bx.cx().layout_of(dst_ty);
223 let mut result = None;
224 for i in 0..src_layout.fields.count() {
225 let src_f = src_layout.field(bx.cx(), i);
226 assert_eq!(src_layout.fields.offset(i).bytes(), 0);
227 assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
231 assert_eq!(src_layout.size, src_f.size);
233 let dst_f = dst_layout.field(bx.cx(), i);
234 assert_ne!(src_f.ty, dst_f.ty);
235 assert_eq!(result, None);
236 result = Some(unsize_thin_ptr(bx, src, src_f.ty, dst_f.ty));
238 let (lldata, llextra) = result.unwrap();
239 // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
240 (bx.bitcast(lldata, bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true)),
241 bx.bitcast(llextra, bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true)))
243 _ => bug!("unsize_thin_ptr: called on bad types"),
247 /// Coerce `src`, which is a reference to a value of type `src_ty`,
248 /// to a value of type `dst_ty` and store the result in `dst`
249 pub fn coerce_unsized_into<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
251 src: PlaceRef<'tcx, Bx::Value>,
252 dst: PlaceRef<'tcx, Bx::Value>
254 let src_ty = src.layout.ty;
255 let dst_ty = dst.layout.ty;
256 let mut coerce_ptr = || {
257 let (base, info) = match bx.load_operand(src).val {
258 OperandValue::Pair(base, info) => {
259 // fat-ptr to fat-ptr unsize preserves the vtable
260 // i.e., &'a fmt::Debug+Send => &'a fmt::Debug
261 // So we need to pointercast the base to ensure
262 // the types match up.
263 let thin_ptr = dst.layout.field(bx.cx(), FAT_PTR_ADDR);
264 (bx.pointercast(base, bx.cx().backend_type(thin_ptr)), info)
266 OperandValue::Immediate(base) => {
267 unsize_thin_ptr(bx, base, src_ty, dst_ty)
269 OperandValue::Ref(..) => bug!()
271 OperandValue::Pair(base, info).store(bx, dst);
273 match (&src_ty.sty, &dst_ty.sty) {
274 (&ty::Ref(..), &ty::Ref(..)) |
275 (&ty::Ref(..), &ty::RawPtr(..)) |
276 (&ty::RawPtr(..), &ty::RawPtr(..)) => {
279 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => {
283 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
284 assert_eq!(def_a, def_b);
286 for i in 0..def_a.variants[VariantIdx::new(0)].fields.len() {
287 let src_f = src.project_field(bx, i);
288 let dst_f = dst.project_field(bx, i);
290 if dst_f.layout.is_zst() {
294 if src_f.layout.ty == dst_f.layout.ty {
295 memcpy_ty(bx, dst_f.llval, dst_f.align, src_f.llval, src_f.align,
296 src_f.layout, MemFlags::empty());
298 coerce_unsized_into(bx, src_f, dst_f);
302 _ => bug!("coerce_unsized_into: invalid coercion {:?} -> {:?}",
308 pub fn cast_shift_expr_rhs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
314 cast_shift_rhs(bx, op, lhs, rhs)
317 fn cast_shift_rhs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
323 // Shifts may have any size int on the rhs
325 let mut rhs_llty = bx.cx().val_ty(rhs);
326 let mut lhs_llty = bx.cx().val_ty(lhs);
327 if bx.cx().type_kind(rhs_llty) == TypeKind::Vector {
328 rhs_llty = bx.cx().element_type(rhs_llty)
330 if bx.cx().type_kind(lhs_llty) == TypeKind::Vector {
331 lhs_llty = bx.cx().element_type(lhs_llty)
333 let rhs_sz = bx.cx().int_width(rhs_llty);
334 let lhs_sz = bx.cx().int_width(lhs_llty);
336 bx.trunc(rhs, lhs_llty)
337 } else if lhs_sz > rhs_sz {
338 // FIXME (#1877: If in the future shifting by negative
339 // values is no longer undefined then this is wrong.
340 bx.zext(rhs, lhs_llty)
349 /// Returns `true` if this session's target will use SEH-based unwinding.
351 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
352 /// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
353 /// 64-bit MinGW) instead of "full SEH".
354 pub fn wants_msvc_seh(sess: &Session) -> bool {
355 sess.target.target.options.is_like_msvc
358 pub fn from_immediate<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
362 if bx.cx().val_ty(val) == bx.cx().type_i1() {
363 bx.zext(val, bx.cx().type_i8())
369 pub fn to_immediate<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
372 layout: layout::TyLayout<'_>,
374 if let layout::Abi::Scalar(ref scalar) = layout.abi {
375 return to_immediate_scalar(bx, val, scalar);
380 pub fn to_immediate_scalar<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
383 scalar: &layout::Scalar,
385 if scalar.is_bool() {
386 return bx.trunc(val, bx.cx().type_i1());
391 pub fn memcpy_ty<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
397 layout: TyLayout<'tcx>,
400 let size = layout.size.bytes();
405 bx.memcpy(dst, dst_align, src, src_align, bx.cx().const_usize(size), flags);
408 pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
409 cx: &'a Bx::CodegenCx,
410 instance: Instance<'tcx>,
412 let _s = if cx.sess().codegen_stats() {
413 let mut instance_name = String::new();
414 DefPathBasedNames::new(cx.tcx(), true, true)
415 .push_def_path(instance.def_id(), &mut instance_name);
416 Some(StatRecorder::new(cx, instance_name))
421 // this is an info! to allow collecting monomorphization statistics
422 // and to allow finding the last function before LLVM aborts from
424 info!("codegen_instance({})", instance);
426 let sig = instance.fn_sig(cx.tcx());
427 let sig = cx.tcx().normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
429 let lldecl = cx.instances().borrow().get(&instance).cloned().unwrap_or_else(||
430 bug!("Instance `{:?}` not already declared", instance));
432 cx.stats().borrow_mut().n_closures += 1;
434 let mir = cx.tcx().instance_mir(instance.def);
435 mir::codegen_mir::<Bx>(cx, lldecl, &mir, instance, sig);
438 /// Creates the `main` function which will initialize the rust runtime and call
439 /// users main function.
440 pub fn maybe_create_entry_wrapper<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
441 cx: &'a Bx::CodegenCx
443 let (main_def_id, span) = match cx.tcx().entry_fn(LOCAL_CRATE) {
444 Some((def_id, _)) => { (def_id, cx.tcx().def_span(def_id)) },
448 let instance = Instance::mono(cx.tcx(), main_def_id);
450 if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) {
451 // We want to create the wrapper in the same codegen unit as Rust's main
456 let main_llfn = cx.get_fn(instance);
458 let et = cx.tcx().entry_fn(LOCAL_CRATE).map(|e| e.1);
460 Some(EntryFnType::Main) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, true),
461 Some(EntryFnType::Start) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, false),
462 None => {} // Do nothing.
465 fn create_entry_fn<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
466 cx: &'a Bx::CodegenCx,
468 rust_main: Bx::Value,
469 rust_main_def_id: DefId,
470 use_start_lang_item: bool,
473 cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int());
475 let main_ret_ty = cx.tcx().fn_sig(rust_main_def_id).output();
476 // Given that `main()` has no arguments,
477 // then its return type cannot have
478 // late-bound regions, since late-bound
479 // regions must appear in the argument
481 let main_ret_ty = cx.tcx().erase_regions(
482 &main_ret_ty.no_bound_vars().unwrap(),
485 if cx.get_defined_value("main").is_some() {
486 // FIXME: We should be smart and show a better diagnostic here.
487 cx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
488 .help("did you use #[no_mangle] on `fn main`? Use #[start] instead")
490 cx.sess().abort_if_errors();
493 let llfn = cx.declare_cfn("main", llfty);
495 // `main` should respect same config for frame pointer elimination as rest of code
496 cx.set_frame_pointer_elimination(llfn);
497 cx.apply_target_cpu_attr(llfn);
499 let mut bx = Bx::new_block(&cx, llfn, "top");
501 bx.insert_reference_to_gdb_debug_scripts_section_global();
503 // Params from native main() used as args for rust start function
504 let param_argc = bx.get_param(0);
505 let param_argv = bx.get_param(1);
506 let arg_argc = bx.intcast(param_argc, cx.type_isize(), true);
507 let arg_argv = param_argv;
509 let (start_fn, args) = if use_start_lang_item {
510 let start_def_id = cx.tcx().require_lang_item(StartFnLangItem);
511 let start_fn = callee::resolve_and_get_fn(
514 cx.tcx().intern_substs(&[main_ret_ty.into()]),
516 (start_fn, vec![bx.pointercast(rust_main, cx.type_ptr_to(cx.type_i8p())),
519 debug!("using user-defined start fn");
520 (rust_main, vec![arg_argc, arg_argv])
523 let result = bx.call(start_fn, &args, None);
524 let cast = bx.intcast(result, cx.type_int(), true);
529 pub const CODEGEN_WORKER_ID: usize = ::std::usize::MAX;
531 pub fn codegen_crate<B: ExtraBackendMethods>(
533 tcx: TyCtxt<'a, 'tcx, 'tcx>,
534 metadata: EncodedMetadata,
535 need_metadata_module: bool,
536 rx: mpsc::Receiver<Box<dyn Any + Send>>
537 ) -> OngoingCodegen<B> {
539 check_for_rustc_errors_attr(tcx);
541 // Skip crate items and just output metadata in -Z no-codegen mode.
542 if tcx.sess.opts.debugging_opts.no_codegen ||
543 !tcx.sess.opts.output_types.should_codegen() {
544 let ongoing_codegen = start_async_codegen(
551 ongoing_codegen.codegen_finished(tcx);
553 assert_and_save_dep_graph(tcx);
555 ongoing_codegen.check_for_errors(tcx.sess);
557 return ongoing_codegen;
560 let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
562 // Run the monomorphization collector and partition the collected items into
564 let codegen_units = tcx.collect_and_partition_mono_items(LOCAL_CRATE).1;
565 let codegen_units = (*codegen_units).clone();
567 // Force all codegen_unit queries so they are already either red or green
568 // when compile_codegen_unit accesses them. We are not able to re-execute
569 // the codegen_unit query from just the DepNode, so an unknown color would
570 // lead to having to re-execute compile_codegen_unit, possibly
572 if tcx.dep_graph.is_fully_enabled() {
573 for cgu in &codegen_units {
574 tcx.codegen_unit(cgu.name().clone());
578 let ongoing_codegen = start_async_codegen(
583 codegen_units.len());
584 let ongoing_codegen = AbortCodegenOnDrop::<B>(Some(ongoing_codegen));
586 // Codegen an allocator shim, if necessary.
588 // If the crate doesn't have an `allocator_kind` set then there's definitely
589 // no shim to generate. Otherwise we also check our dependency graph for all
590 // our output crate types. If anything there looks like its a `Dynamic`
591 // linkage, then it's already got an allocator shim and we'll be using that
592 // one instead. If nothing exists then it's our job to generate the
594 let any_dynamic_crate = tcx.sess.dependency_formats.borrow()
597 use rustc::middle::dependency_format::Linkage;
598 list.iter().any(|&linkage| linkage == Linkage::Dynamic)
600 let allocator_module = if any_dynamic_crate {
602 } else if let Some(kind) = *tcx.sess.allocator_kind.get() {
603 let llmod_id = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
605 Some("allocator")).as_str()
607 let mut modules = backend.new_metadata(tcx, &llmod_id);
608 time(tcx.sess, "write allocator module", || {
609 backend.codegen_allocator(tcx, &mut modules, kind)
614 module_llvm: modules,
615 kind: ModuleKind::Allocator,
621 if let Some(allocator_module) = allocator_module {
622 ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module);
625 if need_metadata_module {
626 // Codegen the encoded metadata.
627 tcx.sess.profiler(|p| p.start_activity("codegen crate metadata"));
629 let metadata_cgu_name = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
631 Some("metadata")).as_str()
633 let mut metadata_llvm_module = backend.new_metadata(tcx, &metadata_cgu_name);
634 time(tcx.sess, "write compressed metadata", || {
635 backend.write_compressed_metadata(tcx, &ongoing_codegen.metadata,
636 &mut metadata_llvm_module);
638 tcx.sess.profiler(|p| p.end_activity("codegen crate metadata"));
640 let metadata_module = ModuleCodegen {
641 name: metadata_cgu_name,
642 module_llvm: metadata_llvm_module,
643 kind: ModuleKind::Metadata,
645 ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module);
648 // We sort the codegen units by size. This way we can schedule work for LLVM
649 // a bit more efficiently.
650 let codegen_units = {
651 let mut codegen_units = codegen_units;
652 codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
656 let mut total_codegen_time = Duration::new(0, 0);
657 let mut all_stats = Stats::default();
659 for cgu in codegen_units.into_iter() {
660 ongoing_codegen.wait_for_signal_to_codegen_item();
661 ongoing_codegen.check_for_errors(tcx.sess);
663 let cgu_reuse = determine_cgu_reuse(tcx, &cgu);
664 tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
668 tcx.sess.profiler(|p| p.start_activity(format!("codegen {}", cgu.name())));
669 let start_time = Instant::now();
670 let stats = backend.compile_codegen_unit(tcx, *cgu.name());
671 all_stats.extend(stats);
672 total_codegen_time += start_time.elapsed();
673 tcx.sess.profiler(|p| p.end_activity(format!("codegen {}", cgu.name())));
676 CguReuse::PreLto => {
677 submit_pre_lto_module_to_llvm(&backend, tcx, CachedModuleCodegen {
678 name: cgu.name().to_string(),
679 source: cgu.work_product(tcx),
683 CguReuse::PostLto => {
684 submit_post_lto_module_to_llvm(&backend, tcx, CachedModuleCodegen {
685 name: cgu.name().to_string(),
686 source: cgu.work_product(tcx),
693 ongoing_codegen.codegen_finished(tcx);
695 // Since the main thread is sometimes blocked during codegen, we keep track
696 // -Ztime-passes output manually.
697 print_time_passes_entry(tcx.sess.time_passes(),
698 "codegen to LLVM IR",
701 ::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
703 symbol_names_test::report_symbol_names(tcx);
705 if tcx.sess.codegen_stats() {
706 println!("--- codegen stats ---");
707 println!("n_glues_created: {}", all_stats.n_glues_created);
708 println!("n_null_glues: {}", all_stats.n_null_glues);
709 println!("n_real_glues: {}", all_stats.n_real_glues);
711 println!("n_fns: {}", all_stats.n_fns);
712 println!("n_inlines: {}", all_stats.n_inlines);
713 println!("n_closures: {}", all_stats.n_closures);
714 println!("fn stats:");
715 all_stats.fn_stats.sort_by_key(|&(_, insns)| insns);
716 for &(ref name, insns) in all_stats.fn_stats.iter() {
717 println!("{} insns, {}", insns, *name);
721 if tcx.sess.count_llvm_insns() {
722 for (k, v) in all_stats.llvm_insns.iter() {
723 println!("{:7} {}", *v, *k);
727 ongoing_codegen.check_for_errors(tcx.sess);
729 assert_and_save_dep_graph(tcx);
730 ongoing_codegen.into_inner()
733 /// A curious wrapper structure whose only purpose is to call `codegen_aborted`
734 /// when it's dropped abnormally.
736 /// In the process of working on rust-lang/rust#55238 a mysterious segfault was
737 /// stumbled upon. The segfault was never reproduced locally, but it was
738 /// suspected to be related to the fact that codegen worker threads were
739 /// sticking around by the time the main thread was exiting, causing issues.
741 /// This structure is an attempt to fix that issue where the `codegen_aborted`
742 /// message will block until all workers have finished. This should ensure that
743 /// even if the main codegen thread panics we'll wait for pending work to
744 /// complete before returning from the main thread, hopefully avoiding
747 /// If you see this comment in the code, then it means that this workaround
748 /// worked! We may yet one day track down the mysterious cause of that
750 struct AbortCodegenOnDrop<B: ExtraBackendMethods>(Option<OngoingCodegen<B>>);
752 impl<B: ExtraBackendMethods> AbortCodegenOnDrop<B> {
753 fn into_inner(mut self) -> OngoingCodegen<B> {
754 self.0.take().unwrap()
758 impl<B: ExtraBackendMethods> Deref for AbortCodegenOnDrop<B> {
759 type Target = OngoingCodegen<B>;
761 fn deref(&self) -> &OngoingCodegen<B> {
762 self.0.as_ref().unwrap()
766 impl<B: ExtraBackendMethods> DerefMut for AbortCodegenOnDrop<B> {
767 fn deref_mut(&mut self) -> &mut OngoingCodegen<B> {
768 self.0.as_mut().unwrap()
772 impl<B: ExtraBackendMethods> Drop for AbortCodegenOnDrop<B> {
774 if let Some(codegen) = self.0.take() {
775 codegen.codegen_aborted();
780 fn assert_and_save_dep_graph<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>) {
783 || ::rustc_incremental::assert_dep_graph(tcx));
786 "serialize dep graph",
787 || ::rustc_incremental::save_dep_graph(tcx));
791 pub fn new(tcx: TyCtxt<'_, '_, '_>) -> CrateInfo {
792 let mut info = CrateInfo {
794 compiler_builtins: None,
795 profiler_runtime: None,
796 sanitizer_runtime: None,
797 is_no_builtins: Default::default(),
798 native_libraries: Default::default(),
799 used_libraries: tcx.native_libraries(LOCAL_CRATE),
800 link_args: tcx.link_args(LOCAL_CRATE),
801 crate_name: Default::default(),
802 used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic),
803 used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic),
804 used_crate_source: Default::default(),
805 lang_item_to_crate: Default::default(),
806 missing_lang_items: Default::default(),
808 let lang_items = tcx.lang_items();
810 let crates = tcx.crates();
812 let n_crates = crates.len();
813 info.native_libraries.reserve(n_crates);
814 info.crate_name.reserve(n_crates);
815 info.used_crate_source.reserve(n_crates);
816 info.missing_lang_items.reserve(n_crates);
818 for &cnum in crates.iter() {
819 info.native_libraries.insert(cnum, tcx.native_libraries(cnum));
820 info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string());
821 info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum));
822 if tcx.is_panic_runtime(cnum) {
823 info.panic_runtime = Some(cnum);
825 if tcx.is_compiler_builtins(cnum) {
826 info.compiler_builtins = Some(cnum);
828 if tcx.is_profiler_runtime(cnum) {
829 info.profiler_runtime = Some(cnum);
831 if tcx.is_sanitizer_runtime(cnum) {
832 info.sanitizer_runtime = Some(cnum);
834 if tcx.is_no_builtins(cnum) {
835 info.is_no_builtins.insert(cnum);
837 let missing = tcx.missing_lang_items(cnum);
838 for &item in missing.iter() {
839 if let Ok(id) = lang_items.require(item) {
840 info.lang_item_to_crate.insert(item, id.krate);
844 // No need to look for lang items that are whitelisted and don't
845 // actually need to exist.
846 let missing = missing.iter()
848 .filter(|&l| !weak_lang_items::whitelisted(tcx, l))
850 info.missing_lang_items.insert(cnum, missing);
857 fn is_codegened_item(tcx: TyCtxt<'_, '_, '_>, id: DefId) -> bool {
858 let (all_mono_items, _) =
859 tcx.collect_and_partition_mono_items(LOCAL_CRATE);
860 all_mono_items.contains(&id)
863 pub fn provide_both(providers: &mut Providers<'_>) {
864 providers.backend_optimization_level = |tcx, cratenum| {
865 let for_speed = match tcx.sess.opts.optimize {
866 // If globally no optimisation is done, #[optimize] has no effect.
868 // This is done because if we ended up "upgrading" to `-O2` here, we’d populate the
869 // pass manager and it is likely that some module-wide passes (such as inliner or
870 // cross-function constant propagation) would ignore the `optnone` annotation we put
871 // on the functions, thus necessarily involving these functions into optimisations.
872 config::OptLevel::No => return config::OptLevel::No,
873 // If globally optimise-speed is already specified, just use that level.
874 config::OptLevel::Less => return config::OptLevel::Less,
875 config::OptLevel::Default => return config::OptLevel::Default,
876 config::OptLevel::Aggressive => return config::OptLevel::Aggressive,
877 // If globally optimize-for-size has been requested, use -O2 instead (if optimize(size)
879 config::OptLevel::Size => config::OptLevel::Default,
880 config::OptLevel::SizeMin => config::OptLevel::Default,
883 let (defids, _) = tcx.collect_and_partition_mono_items(cratenum);
885 let hir::CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
887 attr::OptimizeAttr::None => continue,
888 attr::OptimizeAttr::Size => continue,
889 attr::OptimizeAttr::Speed => {
894 return tcx.sess.opts.optimize;
897 providers.dllimport_foreign_items = |tcx, krate| {
898 let module_map = tcx.foreign_modules(krate);
899 let module_map = module_map.iter()
900 .map(|lib| (lib.def_id, lib))
901 .collect::<FxHashMap<_, _>>();
903 let dllimports = tcx.native_libraries(krate)
906 if lib.kind != cstore::NativeLibraryKind::NativeUnknown {
909 let cfg = match lib.cfg {
910 Some(ref cfg) => cfg,
913 attr::cfg_matches(cfg, &tcx.sess.parse_sess, None)
915 .filter_map(|lib| lib.foreign_module)
916 .map(|id| &module_map[&id])
917 .flat_map(|module| module.foreign_items.iter().cloned())
922 providers.is_dllimport_foreign_item = |tcx, def_id| {
923 tcx.dllimport_foreign_items(def_id.krate).contains(&def_id)
927 fn determine_cgu_reuse<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
928 cgu: &CodegenUnit<'tcx>)
930 if !tcx.dep_graph.is_fully_enabled() {
934 let work_product_id = &cgu.work_product_id();
935 if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
936 // We don't have anything cached for this CGU. This can happen
937 // if the CGU did not exist in the previous session.
941 // Try to mark the CGU as green. If it we can do so, it means that nothing
942 // affecting the LLVM module has changed and we can re-use a cached version.
943 // If we compile with any kind of LTO, this means we can re-use the bitcode
944 // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
945 // know that later). If we are not doing LTO, there is only one optimized
946 // version of each module, so we re-use that.
947 let dep_node = cgu.codegen_dep_node(tcx);
948 assert!(!tcx.dep_graph.dep_node_exists(&dep_node),
949 "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
952 if tcx.dep_graph.try_mark_green(tcx, &dep_node).is_some() {
953 // We can re-use either the pre- or the post-thinlto state
954 if tcx.sess.lto() != Lto::No {