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::{CachedModuleCodegen, CrateInfo, MemFlags, ModuleCodegen, ModuleKind};
17 use crate::back::write::{
18 OngoingCodegen, start_async_codegen, submit_pre_lto_module_to_llvm,
19 submit_post_lto_module_to_llvm,
21 use crate::common::{RealPredicate, TypeKind, IntPredicate};
24 use crate::mir::operand::OperandValue;
25 use crate::mir::place::PlaceRef;
28 use rustc::dep_graph::cgu_reuse_tracker::CguReuse;
30 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
31 use rustc::middle::cstore::EncodedMetadata;
32 use rustc::middle::lang_items::StartFnLangItem;
33 use rustc::middle::weak_lang_items;
34 use rustc::mir::mono::{CodegenUnitNameBuilder, CodegenUnit, MonoItem};
35 use rustc::ty::{self, Ty, TyCtxt, Instance};
36 use rustc::ty::layout::{self, Align, TyLayout, LayoutOf, VariantIdx, HasTyCtxt};
37 use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
38 use rustc::ty::query::Providers;
39 use rustc::middle::cstore::{self, LinkagePreference};
40 use rustc::util::common::{time, print_time_passes_entry, set_time_depth, time_depth};
41 use rustc::session::config::{self, EntryFnType, Lto};
42 use rustc::session::Session;
43 use rustc::util::nodemap::FxHashMap;
44 use rustc_index::vec::Idx;
45 use rustc_codegen_utils::{symbol_names_test, check_for_rustc_errors_attr};
50 use std::ops::{Deref, DerefMut};
51 use std::time::{Instant, Duration};
53 pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind,
57 hir::BinOpKind::Eq => IntPredicate::IntEQ,
58 hir::BinOpKind::Ne => IntPredicate::IntNE,
59 hir::BinOpKind::Lt => if signed { IntPredicate::IntSLT } else { IntPredicate::IntULT },
60 hir::BinOpKind::Le => if signed { IntPredicate::IntSLE } else { IntPredicate::IntULE },
61 hir::BinOpKind::Gt => if signed { IntPredicate::IntSGT } else { IntPredicate::IntUGT },
62 hir::BinOpKind::Ge => if signed { IntPredicate::IntSGE } else { IntPredicate::IntUGE },
64 bug!("comparison_op_to_icmp_predicate: expected comparison operator, \
71 pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> RealPredicate {
73 hir::BinOpKind::Eq => RealPredicate::RealOEQ,
74 hir::BinOpKind::Ne => RealPredicate::RealUNE,
75 hir::BinOpKind::Lt => RealPredicate::RealOLT,
76 hir::BinOpKind::Le => RealPredicate::RealOLE,
77 hir::BinOpKind::Gt => RealPredicate::RealOGT,
78 hir::BinOpKind::Ge => RealPredicate::RealOGE,
80 bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \
87 pub fn compare_simd_types<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
95 let signed = match t.kind {
97 let cmp = bin_op_to_fcmp_predicate(op);
98 let cmp = bx.fcmp(cmp, lhs, rhs);
99 return bx.sext(cmp, ret_ty);
101 ty::Uint(_) => false,
103 _ => bug!("compare_simd_types: invalid SIMD type"),
106 let cmp = bin_op_to_icmp_predicate(op, signed);
107 let cmp = bx.icmp(cmp, lhs, rhs);
108 // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
109 // to get the correctly sized type. This will compile to a single instruction
110 // once the IR is converted to assembly if the SIMD instruction is supported
111 // by the target architecture.
115 /// Retrieves the information we are losing (making dynamic) in an unsizing
118 /// The `old_info` argument is a bit odd. It is intended for use in an upcast,
119 /// where the new vtable for an object will be derived from the old one.
120 pub fn unsized_info<'tcx, Cx: CodegenMethods<'tcx>>(
124 old_info: Option<Cx::Value>,
126 let (source, target) =
127 cx.tcx().struct_lockstep_tails_erasing_lifetimes(source, target, cx.param_env());
128 match (&source.kind, &target.kind) {
129 (&ty::Array(_, len), &ty::Slice(_)) => {
130 cx.const_usize(len.eval_usize(cx.tcx(), ty::ParamEnv::reveal_all()))
132 (&ty::Dynamic(..), &ty::Dynamic(..)) => {
133 // For now, upcasts are limited to changes in marker
134 // traits, and hence never actually require an actual
135 // change to the vtable.
136 old_info.expect("unsized_info: missing old info for trait upcast")
138 (_, &ty::Dynamic(ref data, ..)) => {
139 let vtable_ptr = cx.layout_of(cx.tcx().mk_mut_ptr(target))
140 .field(cx, FAT_PTR_EXTRA);
142 meth::get_vtable(cx, source, data.principal()),
143 cx.backend_type(vtable_ptr),
147 "unsized_info: invalid unsizing {:?} -> {:?}",
153 /// Coerces `src` to `dst_ty`. `src_ty` must be a thin pointer.
154 pub fn unsize_thin_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
159 ) -> (Bx::Value, Bx::Value) {
160 debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
161 match (&src_ty.kind, &dst_ty.kind) {
165 &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) |
166 (&ty::RawPtr(ty::TypeAndMut { ty: a, .. }),
167 &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => {
168 assert!(bx.cx().type_is_sized(a));
169 let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
170 (bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
172 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
173 assert_eq!(def_a, def_b);
175 let src_layout = bx.cx().layout_of(src_ty);
176 let dst_layout = bx.cx().layout_of(dst_ty);
177 let mut result = None;
178 for i in 0..src_layout.fields.count() {
179 let src_f = src_layout.field(bx.cx(), i);
180 assert_eq!(src_layout.fields.offset(i).bytes(), 0);
181 assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
185 assert_eq!(src_layout.size, src_f.size);
187 let dst_f = dst_layout.field(bx.cx(), i);
188 assert_ne!(src_f.ty, dst_f.ty);
189 assert_eq!(result, None);
190 result = Some(unsize_thin_ptr(bx, src, src_f.ty, dst_f.ty));
192 let (lldata, llextra) = result.unwrap();
193 // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
194 // FIXME(eddyb) move these out of this `match` arm, so they're always
195 // applied, uniformly, no matter the source/destination types.
196 (bx.bitcast(lldata, bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true)),
197 bx.bitcast(llextra, bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true)))
199 _ => bug!("unsize_thin_ptr: called on bad types"),
203 /// Coerces `src`, which is a reference to a value of type `src_ty`,
204 /// to a value of type `dst_ty`, and stores the result in `dst`.
205 pub fn coerce_unsized_into<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
207 src: PlaceRef<'tcx, Bx::Value>,
208 dst: PlaceRef<'tcx, Bx::Value>,
210 let src_ty = src.layout.ty;
211 let dst_ty = dst.layout.ty;
212 match (&src_ty.kind, &dst_ty.kind) {
213 (&ty::Ref(..), &ty::Ref(..)) |
214 (&ty::Ref(..), &ty::RawPtr(..)) |
215 (&ty::RawPtr(..), &ty::RawPtr(..)) => {
216 let (base, info) = match bx.load_operand(src).val {
217 OperandValue::Pair(base, info) => {
218 // fat-ptr to fat-ptr unsize preserves the vtable
219 // i.e., &'a fmt::Debug+Send => &'a fmt::Debug
220 // So we need to pointercast the base to ensure
221 // the types match up.
222 // FIXME(eddyb) use `scalar_pair_element_backend_type` here,
223 // like `unsize_thin_ptr` does.
224 let thin_ptr = dst.layout.field(bx.cx(), FAT_PTR_ADDR);
225 (bx.pointercast(base, bx.cx().backend_type(thin_ptr)), info)
227 OperandValue::Immediate(base) => {
228 unsize_thin_ptr(bx, base, src_ty, dst_ty)
230 OperandValue::Ref(..) => bug!()
232 OperandValue::Pair(base, info).store(bx, dst);
235 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
236 assert_eq!(def_a, def_b);
238 for i in 0..def_a.variants[VariantIdx::new(0)].fields.len() {
239 let src_f = src.project_field(bx, i);
240 let dst_f = dst.project_field(bx, i);
242 if dst_f.layout.is_zst() {
246 if src_f.layout.ty == dst_f.layout.ty {
247 memcpy_ty(bx, dst_f.llval, dst_f.align, src_f.llval, src_f.align,
248 src_f.layout, MemFlags::empty());
250 coerce_unsized_into(bx, src_f, dst_f);
255 "coerce_unsized_into: invalid coercion {:?} -> {:?}",
262 pub fn cast_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
268 cast_shift_rhs(bx, op, lhs, rhs)
271 fn cast_shift_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
277 // Shifts may have any size int on the rhs
279 let mut rhs_llty = bx.cx().val_ty(rhs);
280 let mut lhs_llty = bx.cx().val_ty(lhs);
281 if bx.cx().type_kind(rhs_llty) == TypeKind::Vector {
282 rhs_llty = bx.cx().element_type(rhs_llty)
284 if bx.cx().type_kind(lhs_llty) == TypeKind::Vector {
285 lhs_llty = bx.cx().element_type(lhs_llty)
287 let rhs_sz = bx.cx().int_width(rhs_llty);
288 let lhs_sz = bx.cx().int_width(lhs_llty);
290 bx.trunc(rhs, lhs_llty)
291 } else if lhs_sz > rhs_sz {
292 // FIXME (#1877: If in the future shifting by negative
293 // values is no longer undefined then this is wrong.
294 bx.zext(rhs, lhs_llty)
303 /// Returns `true` if this session's target will use SEH-based unwinding.
305 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
306 /// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
307 /// 64-bit MinGW) instead of "full SEH".
308 pub fn wants_msvc_seh(sess: &Session) -> bool {
309 sess.target.target.options.is_like_msvc
312 pub fn from_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
316 if bx.cx().val_ty(val) == bx.cx().type_i1() {
317 bx.zext(val, bx.cx().type_i8())
323 pub fn to_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
326 layout: layout::TyLayout<'_>,
328 if let layout::Abi::Scalar(ref scalar) = layout.abi {
329 return to_immediate_scalar(bx, val, scalar);
334 pub fn to_immediate_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
337 scalar: &layout::Scalar,
339 if scalar.is_bool() {
340 return bx.trunc(val, bx.cx().type_i1());
345 pub fn memcpy_ty<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
351 layout: TyLayout<'tcx>,
354 let size = layout.size.bytes();
359 bx.memcpy(dst, dst_align, src, src_align, bx.cx().const_usize(size), flags);
362 pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
363 cx: &'a Bx::CodegenCx,
364 instance: Instance<'tcx>,
366 // this is an info! to allow collecting monomorphization statistics
367 // and to allow finding the last function before LLVM aborts from
369 info!("codegen_instance({})", instance);
371 let sig = instance.fn_sig(cx.tcx());
372 let sig = cx.tcx().normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
374 let lldecl = cx.get_fn(instance);
376 let mir = cx.tcx().instance_mir(instance.def);
377 mir::codegen_mir::<Bx>(cx, lldecl, &mir, instance, sig);
380 /// Creates the `main` function which will initialize the rust runtime and call
381 /// users main function.
382 pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(cx: &'a Bx::CodegenCx) {
383 let (main_def_id, span) = match cx.tcx().entry_fn(LOCAL_CRATE) {
384 Some((def_id, _)) => { (def_id, cx.tcx().def_span(def_id)) },
388 let instance = Instance::mono(cx.tcx(), main_def_id);
390 if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) {
391 // We want to create the wrapper in the same codegen unit as Rust's main
396 let main_llfn = cx.get_fn_addr(instance);
398 let et = cx.tcx().entry_fn(LOCAL_CRATE).map(|e| e.1);
400 Some(EntryFnType::Main) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, true),
401 Some(EntryFnType::Start) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, false),
402 None => {} // Do nothing.
405 fn create_entry_fn<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
406 cx: &'a Bx::CodegenCx,
408 rust_main: Bx::Value,
409 rust_main_def_id: DefId,
410 use_start_lang_item: bool,
412 // The entry function is either `int main(void)` or `int main(int argc, char **argv)`,
413 // depending on whether the target needs `argc` and `argv` to be passed in.
414 let llfty = if cx.sess().target.target.options.main_needs_argc_argv {
415 cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int())
417 cx.type_func(&[], cx.type_int())
420 let main_ret_ty = cx.tcx().fn_sig(rust_main_def_id).output();
421 // Given that `main()` has no arguments,
422 // then its return type cannot have
423 // late-bound regions, since late-bound
424 // regions must appear in the argument
426 let main_ret_ty = cx.tcx().erase_regions(
427 &main_ret_ty.no_bound_vars().unwrap(),
430 if cx.get_defined_value("main").is_some() {
431 // FIXME: We should be smart and show a better diagnostic here.
432 cx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
433 .help("did you use `#[no_mangle]` on `fn main`? Use `#[start]` instead")
435 cx.sess().abort_if_errors();
438 let llfn = cx.declare_cfn("main", llfty);
440 // `main` should respect same config for frame pointer elimination as rest of code
441 cx.set_frame_pointer_elimination(llfn);
442 cx.apply_target_cpu_attr(llfn);
444 let mut bx = Bx::new_block(&cx, llfn, "top");
446 bx.insert_reference_to_gdb_debug_scripts_section_global();
448 let (arg_argc, arg_argv) = get_argc_argv(cx, &mut bx);
450 let (start_fn, args) = if use_start_lang_item {
451 let start_def_id = cx.tcx().require_lang_item(StartFnLangItem, None);
452 let start_fn = cx.get_fn_addr(
453 ty::Instance::resolve(
455 ty::ParamEnv::reveal_all(),
457 cx.tcx().intern_substs(&[main_ret_ty.into()]),
460 (start_fn, vec![bx.pointercast(rust_main, cx.type_ptr_to(cx.type_i8p())),
463 debug!("using user-defined start fn");
464 (rust_main, vec![arg_argc, arg_argv])
467 let result = bx.call(start_fn, &args, None);
468 let cast = bx.intcast(result, cx.type_int(), true);
473 /// Obtain the `argc` and `argv` values to pass to the rust start function.
474 fn get_argc_argv<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
475 cx: &'a Bx::CodegenCx,
477 ) -> (Bx::Value, Bx::Value)
479 if cx.sess().target.target.options.main_needs_argc_argv {
480 // Params from native `main()` used as args for rust start function
481 let param_argc = bx.get_param(0);
482 let param_argv = bx.get_param(1);
483 let arg_argc = bx.intcast(param_argc, cx.type_isize(), true);
484 let arg_argv = param_argv;
487 // The Rust start function doesn't need `argc` and `argv`, so just pass zeros.
488 let arg_argc = bx.const_int(cx.type_int(), 0);
489 let arg_argv = bx.const_null(cx.type_ptr_to(cx.type_i8p()));
494 pub const CODEGEN_WORKER_ID: usize = ::std::usize::MAX;
496 pub fn codegen_crate<B: ExtraBackendMethods>(
499 metadata: EncodedMetadata,
500 need_metadata_module: bool,
501 ) -> OngoingCodegen<B> {
502 check_for_rustc_errors_attr(tcx);
504 // Skip crate items and just output metadata in -Z no-codegen mode.
505 if tcx.sess.opts.debugging_opts.no_codegen ||
506 !tcx.sess.opts.output_types.should_codegen() {
507 let ongoing_codegen = start_async_codegen(backend, tcx, metadata, 1);
509 ongoing_codegen.codegen_finished(tcx);
511 assert_and_save_dep_graph(tcx);
513 ongoing_codegen.check_for_errors(tcx.sess);
515 return ongoing_codegen;
518 let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
520 // Run the monomorphization collector and partition the collected items into
522 let codegen_units = tcx.collect_and_partition_mono_items(LOCAL_CRATE).1;
523 let codegen_units = (*codegen_units).clone();
525 // Force all codegen_unit queries so they are already either red or green
526 // when compile_codegen_unit accesses them. We are not able to re-execute
527 // the codegen_unit query from just the DepNode, so an unknown color would
528 // lead to having to re-execute compile_codegen_unit, possibly
530 if tcx.dep_graph.is_fully_enabled() {
531 for cgu in &codegen_units {
532 tcx.codegen_unit(cgu.name());
536 let ongoing_codegen = start_async_codegen(backend.clone(), tcx, metadata, codegen_units.len());
537 let ongoing_codegen = AbortCodegenOnDrop::<B>(Some(ongoing_codegen));
539 // Codegen an allocator shim, if necessary.
541 // If the crate doesn't have an `allocator_kind` set then there's definitely
542 // no shim to generate. Otherwise we also check our dependency graph for all
543 // our output crate types. If anything there looks like its a `Dynamic`
544 // linkage, then it's already got an allocator shim and we'll be using that
545 // one instead. If nothing exists then it's our job to generate the
547 let any_dynamic_crate = tcx.dependency_formats(LOCAL_CRATE)
550 use rustc::middle::dependency_format::Linkage;
551 list.iter().any(|&linkage| linkage == Linkage::Dynamic)
553 let allocator_module = if any_dynamic_crate {
555 } else if let Some(kind) = tcx.allocator_kind() {
556 let llmod_id = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
558 Some("allocator")).to_string();
559 let mut modules = backend.new_metadata(tcx, &llmod_id);
560 time(tcx.sess, "write allocator module", || {
561 backend.codegen_allocator(tcx, &mut modules, kind)
566 module_llvm: modules,
567 kind: ModuleKind::Allocator,
573 if let Some(allocator_module) = allocator_module {
574 ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module);
577 if need_metadata_module {
578 // Codegen the encoded metadata.
579 let metadata_cgu_name = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
581 Some("metadata")).to_string();
582 let mut metadata_llvm_module = backend.new_metadata(tcx, &metadata_cgu_name);
583 time(tcx.sess, "write compressed metadata", || {
584 backend.write_compressed_metadata(tcx, &ongoing_codegen.metadata,
585 &mut metadata_llvm_module);
588 let metadata_module = ModuleCodegen {
589 name: metadata_cgu_name,
590 module_llvm: metadata_llvm_module,
591 kind: ModuleKind::Metadata,
593 ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module);
596 // We sort the codegen units by size. This way we can schedule work for LLVM
597 // a bit more efficiently.
598 let codegen_units = {
599 let mut codegen_units = codegen_units;
600 codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
604 let mut total_codegen_time = Duration::new(0, 0);
606 for cgu in codegen_units.into_iter() {
607 ongoing_codegen.wait_for_signal_to_codegen_item();
608 ongoing_codegen.check_for_errors(tcx.sess);
610 let cgu_reuse = determine_cgu_reuse(tcx, &cgu);
611 tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
615 let start_time = Instant::now();
616 backend.compile_codegen_unit(tcx, cgu.name(), &ongoing_codegen.coordinator_send);
617 total_codegen_time += start_time.elapsed();
620 CguReuse::PreLto => {
621 submit_pre_lto_module_to_llvm(&backend, tcx, &ongoing_codegen.coordinator_send,
622 CachedModuleCodegen {
623 name: cgu.name().to_string(),
624 source: cgu.work_product(tcx),
628 CguReuse::PostLto => {
629 submit_post_lto_module_to_llvm(&backend, &ongoing_codegen.coordinator_send,
630 CachedModuleCodegen {
631 name: cgu.name().to_string(),
632 source: cgu.work_product(tcx),
639 ongoing_codegen.codegen_finished(tcx);
641 // Since the main thread is sometimes blocked during codegen, we keep track
642 // -Ztime-passes output manually.
643 let time_depth = time_depth();
644 set_time_depth(time_depth + 1);
645 print_time_passes_entry(tcx.sess.time_passes(),
646 "codegen to LLVM IR",
648 set_time_depth(time_depth);
650 ::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
652 symbol_names_test::report_symbol_names(tcx);
654 ongoing_codegen.check_for_errors(tcx.sess);
656 assert_and_save_dep_graph(tcx);
657 ongoing_codegen.into_inner()
660 /// A curious wrapper structure whose only purpose is to call `codegen_aborted`
661 /// when it's dropped abnormally.
663 /// In the process of working on rust-lang/rust#55238 a mysterious segfault was
664 /// stumbled upon. The segfault was never reproduced locally, but it was
665 /// suspected to be related to the fact that codegen worker threads were
666 /// sticking around by the time the main thread was exiting, causing issues.
668 /// This structure is an attempt to fix that issue where the `codegen_aborted`
669 /// message will block until all workers have finished. This should ensure that
670 /// even if the main codegen thread panics we'll wait for pending work to
671 /// complete before returning from the main thread, hopefully avoiding
674 /// If you see this comment in the code, then it means that this workaround
675 /// worked! We may yet one day track down the mysterious cause of that
677 struct AbortCodegenOnDrop<B: ExtraBackendMethods>(Option<OngoingCodegen<B>>);
679 impl<B: ExtraBackendMethods> AbortCodegenOnDrop<B> {
680 fn into_inner(mut self) -> OngoingCodegen<B> {
681 self.0.take().unwrap()
685 impl<B: ExtraBackendMethods> Deref for AbortCodegenOnDrop<B> {
686 type Target = OngoingCodegen<B>;
688 fn deref(&self) -> &OngoingCodegen<B> {
689 self.0.as_ref().unwrap()
693 impl<B: ExtraBackendMethods> DerefMut for AbortCodegenOnDrop<B> {
694 fn deref_mut(&mut self) -> &mut OngoingCodegen<B> {
695 self.0.as_mut().unwrap()
699 impl<B: ExtraBackendMethods> Drop for AbortCodegenOnDrop<B> {
701 if let Some(codegen) = self.0.take() {
702 codegen.codegen_aborted();
707 fn assert_and_save_dep_graph(tcx: TyCtxt<'_>) {
710 || ::rustc_incremental::assert_dep_graph(tcx));
713 "serialize dep graph",
714 || ::rustc_incremental::save_dep_graph(tcx));
718 pub fn new(tcx: TyCtxt<'_>) -> CrateInfo {
719 let mut info = CrateInfo {
721 compiler_builtins: None,
722 profiler_runtime: None,
723 sanitizer_runtime: None,
724 is_no_builtins: Default::default(),
725 native_libraries: Default::default(),
726 used_libraries: tcx.native_libraries(LOCAL_CRATE),
727 link_args: tcx.link_args(LOCAL_CRATE),
728 crate_name: Default::default(),
729 used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic),
730 used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic),
731 used_crate_source: Default::default(),
732 lang_item_to_crate: Default::default(),
733 missing_lang_items: Default::default(),
734 dependency_formats: tcx.dependency_formats(LOCAL_CRATE),
736 let lang_items = tcx.lang_items();
738 let crates = tcx.crates();
740 let n_crates = crates.len();
741 info.native_libraries.reserve(n_crates);
742 info.crate_name.reserve(n_crates);
743 info.used_crate_source.reserve(n_crates);
744 info.missing_lang_items.reserve(n_crates);
746 for &cnum in crates.iter() {
747 info.native_libraries.insert(cnum, tcx.native_libraries(cnum));
748 info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string());
749 info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum));
750 if tcx.is_panic_runtime(cnum) {
751 info.panic_runtime = Some(cnum);
753 if tcx.is_compiler_builtins(cnum) {
754 info.compiler_builtins = Some(cnum);
756 if tcx.is_profiler_runtime(cnum) {
757 info.profiler_runtime = Some(cnum);
759 if tcx.is_sanitizer_runtime(cnum) {
760 info.sanitizer_runtime = Some(cnum);
762 if tcx.is_no_builtins(cnum) {
763 info.is_no_builtins.insert(cnum);
765 let missing = tcx.missing_lang_items(cnum);
766 for &item in missing.iter() {
767 if let Ok(id) = lang_items.require(item) {
768 info.lang_item_to_crate.insert(item, id.krate);
772 // No need to look for lang items that are whitelisted and don't
773 // actually need to exist.
774 let missing = missing.iter()
776 .filter(|&l| !weak_lang_items::whitelisted(tcx, l))
778 info.missing_lang_items.insert(cnum, missing);
785 pub fn provide_both(providers: &mut Providers<'_>) {
786 providers.backend_optimization_level = |tcx, cratenum| {
787 let for_speed = match tcx.sess.opts.optimize {
788 // If globally no optimisation is done, #[optimize] has no effect.
790 // This is done because if we ended up "upgrading" to `-O2` here, we’d populate the
791 // pass manager and it is likely that some module-wide passes (such as inliner or
792 // cross-function constant propagation) would ignore the `optnone` annotation we put
793 // on the functions, thus necessarily involving these functions into optimisations.
794 config::OptLevel::No => return config::OptLevel::No,
795 // If globally optimise-speed is already specified, just use that level.
796 config::OptLevel::Less => return config::OptLevel::Less,
797 config::OptLevel::Default => return config::OptLevel::Default,
798 config::OptLevel::Aggressive => return config::OptLevel::Aggressive,
799 // If globally optimize-for-size has been requested, use -O2 instead (if optimize(size)
801 config::OptLevel::Size => config::OptLevel::Default,
802 config::OptLevel::SizeMin => config::OptLevel::Default,
805 let (defids, _) = tcx.collect_and_partition_mono_items(cratenum);
807 let hir::CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
809 attr::OptimizeAttr::None => continue,
810 attr::OptimizeAttr::Size => continue,
811 attr::OptimizeAttr::Speed => {
816 return tcx.sess.opts.optimize;
819 providers.dllimport_foreign_items = |tcx, krate| {
820 let module_map = tcx.foreign_modules(krate);
821 let module_map = module_map.iter()
822 .map(|lib| (lib.def_id, lib))
823 .collect::<FxHashMap<_, _>>();
825 let dllimports = tcx.native_libraries(krate)
828 if lib.kind != cstore::NativeLibraryKind::NativeUnknown {
831 let cfg = match lib.cfg {
832 Some(ref cfg) => cfg,
835 attr::cfg_matches(cfg, &tcx.sess.parse_sess, None)
837 .filter_map(|lib| lib.foreign_module)
838 .map(|id| &module_map[&id])
839 .flat_map(|module| module.foreign_items.iter().cloned())
841 tcx.arena.alloc(dllimports)
844 providers.is_dllimport_foreign_item = |tcx, def_id| {
845 tcx.dllimport_foreign_items(def_id.krate).contains(&def_id)
849 fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
850 if !tcx.dep_graph.is_fully_enabled() {
854 let work_product_id = &cgu.work_product_id();
855 if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
856 // We don't have anything cached for this CGU. This can happen
857 // if the CGU did not exist in the previous session.
861 // Try to mark the CGU as green. If it we can do so, it means that nothing
862 // affecting the LLVM module has changed and we can re-use a cached version.
863 // If we compile with any kind of LTO, this means we can re-use the bitcode
864 // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
865 // know that later). If we are not doing LTO, there is only one optimized
866 // version of each module, so we re-use that.
867 let dep_node = cgu.codegen_dep_node(tcx);
868 assert!(!tcx.dep_graph.dep_node_exists(&dep_node),
869 "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
872 if tcx.dep_graph.try_mark_green(tcx, &dep_node).is_some() {
873 // We can re-use either the pre- or the post-thinlto state
874 if tcx.sess.lto() != Lto::No {