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::{CodegenUnitNameBuilder, CodegenUnit, MonoItem};
24 use rustc::ty::{self, Ty, TyCtxt, Instance};
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, set_time_depth, time_depth};
29 use rustc::session::config::{self, EntryFnType, Lto};
30 use rustc::session::Session;
31 use rustc::util::nodemap::FxHashMap;
32 use rustc_index::vec::Idx;
33 use rustc_codegen_utils::{symbol_names_test, check_for_rustc_errors_attr};
34 use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
35 use crate::mir::place::PlaceRef;
36 use crate::back::write::{OngoingCodegen, start_async_codegen, submit_pre_lto_module_to_llvm,
37 submit_post_lto_module_to_llvm};
38 use crate::{MemFlags, CrateInfo};
39 use crate::common::{RealPredicate, TypeKind, IntPredicate};
46 use std::ops::{Deref, DerefMut};
47 use std::time::{Instant, Duration};
52 use crate::mir::operand::OperandValue;
54 pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind,
58 hir::BinOpKind::Eq => IntPredicate::IntEQ,
59 hir::BinOpKind::Ne => IntPredicate::IntNE,
60 hir::BinOpKind::Lt => if signed { IntPredicate::IntSLT } else { IntPredicate::IntULT },
61 hir::BinOpKind::Le => if signed { IntPredicate::IntSLE } else { IntPredicate::IntULE },
62 hir::BinOpKind::Gt => if signed { IntPredicate::IntSGT } else { IntPredicate::IntUGT },
63 hir::BinOpKind::Ge => if signed { IntPredicate::IntSGE } else { IntPredicate::IntUGE },
65 bug!("comparison_op_to_icmp_predicate: expected comparison operator, \
72 pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> RealPredicate {
74 hir::BinOpKind::Eq => RealPredicate::RealOEQ,
75 hir::BinOpKind::Ne => RealPredicate::RealUNE,
76 hir::BinOpKind::Lt => RealPredicate::RealOLT,
77 hir::BinOpKind::Le => RealPredicate::RealOLE,
78 hir::BinOpKind::Gt => RealPredicate::RealOGT,
79 hir::BinOpKind::Ge => RealPredicate::RealOGE,
81 bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \
88 pub fn compare_simd_types<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
96 let signed = match t.kind {
98 let cmp = bin_op_to_fcmp_predicate(op);
99 let cmp = bx.fcmp(cmp, lhs, rhs);
100 return bx.sext(cmp, ret_ty);
102 ty::Uint(_) => false,
104 _ => bug!("compare_simd_types: invalid SIMD type"),
107 let cmp = bin_op_to_icmp_predicate(op, signed);
108 let cmp = bx.icmp(cmp, lhs, rhs);
109 // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
110 // to get the correctly sized type. This will compile to a single instruction
111 // once the IR is converted to assembly if the SIMD instruction is supported
112 // by the target architecture.
116 /// Retrieves the information we are losing (making dynamic) in an unsizing
119 /// The `old_info` argument is a bit funny. It is intended for use
120 /// in an upcast, where the new vtable for an object will be derived
121 /// from the old one.
122 pub fn unsized_info<'tcx, Cx: CodegenMethods<'tcx>>(
126 old_info: Option<Cx::Value>,
128 let (source, target) =
129 cx.tcx().struct_lockstep_tails_erasing_lifetimes(source, target, cx.param_env());
130 match (&source.kind, &target.kind) {
131 (&ty::Array(_, len), &ty::Slice(_)) => {
132 cx.const_usize(len.eval_usize(cx.tcx(), ty::ParamEnv::reveal_all()))
134 (&ty::Dynamic(..), &ty::Dynamic(..)) => {
135 // For now, upcasts are limited to changes in marker
136 // traits, and hence never actually require an actual
137 // change to the vtable.
138 old_info.expect("unsized_info: missing old info for trait upcast")
140 (_, &ty::Dynamic(ref data, ..)) => {
141 let vtable_ptr = cx.layout_of(cx.tcx().mk_mut_ptr(target))
142 .field(cx, FAT_PTR_EXTRA);
143 cx.const_ptrcast(meth::get_vtable(cx, source, data.principal()),
144 cx.backend_type(vtable_ptr))
146 _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}",
152 /// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer.
153 pub fn unsize_thin_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
158 ) -> (Bx::Value, Bx::Value) {
159 debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
160 match (&src_ty.kind, &dst_ty.kind) {
164 &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) |
165 (&ty::RawPtr(ty::TypeAndMut { ty: a, .. }),
166 &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => {
167 assert!(bx.cx().type_is_sized(a));
168 let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b)));
169 (bx.pointercast(src, ptr_ty), unsized_info(bx.cx(), a, b, None))
171 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
172 assert_eq!(def_a, def_b);
174 let src_layout = bx.cx().layout_of(src_ty);
175 let dst_layout = bx.cx().layout_of(dst_ty);
176 let mut result = None;
177 for i in 0..src_layout.fields.count() {
178 let src_f = src_layout.field(bx.cx(), i);
179 assert_eq!(src_layout.fields.offset(i).bytes(), 0);
180 assert_eq!(dst_layout.fields.offset(i).bytes(), 0);
184 assert_eq!(src_layout.size, src_f.size);
186 let dst_f = dst_layout.field(bx.cx(), i);
187 assert_ne!(src_f.ty, dst_f.ty);
188 assert_eq!(result, None);
189 result = Some(unsize_thin_ptr(bx, src, src_f.ty, dst_f.ty));
191 let (lldata, llextra) = result.unwrap();
192 // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types.
193 // FIXME(eddyb) move these out of this `match` arm, so they're always
194 // applied, uniformly, no matter the source/destination types.
195 (bx.bitcast(lldata, bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true)),
196 bx.bitcast(llextra, bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true)))
198 _ => bug!("unsize_thin_ptr: called on bad types"),
202 /// Coerce `src`, which is a reference to a value of type `src_ty`,
203 /// to a value of type `dst_ty` and store the result in `dst`
204 pub fn coerce_unsized_into<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
206 src: PlaceRef<'tcx, Bx::Value>,
207 dst: PlaceRef<'tcx, Bx::Value>,
209 let src_ty = src.layout.ty;
210 let dst_ty = dst.layout.ty;
211 match (&src_ty.kind, &dst_ty.kind) {
212 (&ty::Ref(..), &ty::Ref(..)) |
213 (&ty::Ref(..), &ty::RawPtr(..)) |
214 (&ty::RawPtr(..), &ty::RawPtr(..)) => {
215 let (base, info) = match bx.load_operand(src).val {
216 OperandValue::Pair(base, info) => {
217 // fat-ptr to fat-ptr unsize preserves the vtable
218 // i.e., &'a fmt::Debug+Send => &'a fmt::Debug
219 // So we need to pointercast the base to ensure
220 // the types match up.
221 // FIXME(eddyb) use `scalar_pair_element_backend_type` here,
222 // like `unsize_thin_ptr` does.
223 let thin_ptr = dst.layout.field(bx.cx(), FAT_PTR_ADDR);
224 (bx.pointercast(base, bx.cx().backend_type(thin_ptr)), info)
226 OperandValue::Immediate(base) => {
227 unsize_thin_ptr(bx, base, src_ty, dst_ty)
229 OperandValue::Ref(..) => bug!()
231 OperandValue::Pair(base, info).store(bx, dst);
234 (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
235 assert_eq!(def_a, def_b);
237 for i in 0..def_a.variants[VariantIdx::new(0)].fields.len() {
238 let src_f = src.project_field(bx, i);
239 let dst_f = dst.project_field(bx, i);
241 if dst_f.layout.is_zst() {
245 if src_f.layout.ty == dst_f.layout.ty {
246 memcpy_ty(bx, dst_f.llval, dst_f.align, src_f.llval, src_f.align,
247 src_f.layout, MemFlags::empty());
249 coerce_unsized_into(bx, src_f, dst_f);
253 _ => bug!("coerce_unsized_into: invalid coercion {:?} -> {:?}",
259 pub fn cast_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
265 cast_shift_rhs(bx, op, lhs, rhs)
268 fn cast_shift_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
274 // Shifts may have any size int on the rhs
276 let mut rhs_llty = bx.cx().val_ty(rhs);
277 let mut lhs_llty = bx.cx().val_ty(lhs);
278 if bx.cx().type_kind(rhs_llty) == TypeKind::Vector {
279 rhs_llty = bx.cx().element_type(rhs_llty)
281 if bx.cx().type_kind(lhs_llty) == TypeKind::Vector {
282 lhs_llty = bx.cx().element_type(lhs_llty)
284 let rhs_sz = bx.cx().int_width(rhs_llty);
285 let lhs_sz = bx.cx().int_width(lhs_llty);
287 bx.trunc(rhs, lhs_llty)
288 } else if lhs_sz > rhs_sz {
289 // FIXME (#1877: If in the future shifting by negative
290 // values is no longer undefined then this is wrong.
291 bx.zext(rhs, lhs_llty)
300 /// Returns `true` if this session's target will use SEH-based unwinding.
302 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
303 /// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
304 /// 64-bit MinGW) instead of "full SEH".
305 pub fn wants_msvc_seh(sess: &Session) -> bool {
306 sess.target.target.options.is_like_msvc
309 pub fn from_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
313 if bx.cx().val_ty(val) == bx.cx().type_i1() {
314 bx.zext(val, bx.cx().type_i8())
320 pub fn to_immediate<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
323 layout: layout::TyLayout<'_>,
325 if let layout::Abi::Scalar(ref scalar) = layout.abi {
326 return to_immediate_scalar(bx, val, scalar);
331 pub fn to_immediate_scalar<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
334 scalar: &layout::Scalar,
336 if scalar.is_bool() {
337 return bx.trunc(val, bx.cx().type_i1());
342 pub fn memcpy_ty<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
348 layout: TyLayout<'tcx>,
351 let size = layout.size.bytes();
356 bx.memcpy(dst, dst_align, src, src_align, bx.cx().const_usize(size), flags);
359 pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
360 cx: &'a Bx::CodegenCx,
361 instance: Instance<'tcx>,
363 // this is an info! to allow collecting monomorphization statistics
364 // and to allow finding the last function before LLVM aborts from
366 info!("codegen_instance({})", instance);
368 let sig = instance.fn_sig(cx.tcx());
369 let sig = cx.tcx().normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
371 let lldecl = cx.get_fn(instance);
373 let mir = cx.tcx().instance_mir(instance.def);
374 mir::codegen_mir::<Bx>(cx, lldecl, &mir, instance, sig);
377 /// Creates the `main` function which will initialize the rust runtime and call
378 /// users main function.
379 pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(cx: &'a Bx::CodegenCx) {
380 let (main_def_id, span) = match cx.tcx().entry_fn(LOCAL_CRATE) {
381 Some((def_id, _)) => { (def_id, cx.tcx().def_span(def_id)) },
385 let instance = Instance::mono(cx.tcx(), main_def_id);
387 if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) {
388 // We want to create the wrapper in the same codegen unit as Rust's main
393 let main_llfn = cx.get_fn_addr(instance);
395 let et = cx.tcx().entry_fn(LOCAL_CRATE).map(|e| e.1);
397 Some(EntryFnType::Main) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, true),
398 Some(EntryFnType::Start) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, false),
399 None => {} // Do nothing.
402 fn create_entry_fn<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
403 cx: &'a Bx::CodegenCx,
405 rust_main: Bx::Value,
406 rust_main_def_id: DefId,
407 use_start_lang_item: bool,
409 // The entry function is either `int main(void)` or `int main(int argc, char **argv)`,
410 // depending on whether the target needs `argc` and `argv` to be passed in.
411 let llfty = if cx.sess().target.target.options.main_needs_argc_argv {
412 cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int())
414 cx.type_func(&[], cx.type_int())
417 let main_ret_ty = cx.tcx().fn_sig(rust_main_def_id).output();
418 // Given that `main()` has no arguments,
419 // then its return type cannot have
420 // late-bound regions, since late-bound
421 // regions must appear in the argument
423 let main_ret_ty = cx.tcx().erase_regions(
424 &main_ret_ty.no_bound_vars().unwrap(),
427 if cx.get_defined_value("main").is_some() {
428 // FIXME: We should be smart and show a better diagnostic here.
429 cx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
430 .help("did you use `#[no_mangle]` on `fn main`? Use `#[start]` instead")
432 cx.sess().abort_if_errors();
435 let llfn = cx.declare_cfn("main", llfty);
437 // `main` should respect same config for frame pointer elimination as rest of code
438 cx.set_frame_pointer_elimination(llfn);
439 cx.apply_target_cpu_attr(llfn);
441 let mut bx = Bx::new_block(&cx, llfn, "top");
443 bx.insert_reference_to_gdb_debug_scripts_section_global();
445 let (arg_argc, arg_argv) = get_argc_argv(cx, &mut bx);
447 let (start_fn, args) = if use_start_lang_item {
448 let start_def_id = cx.tcx().require_lang_item(StartFnLangItem, None);
449 let start_fn = cx.get_fn_addr(
450 ty::Instance::resolve(
452 ty::ParamEnv::reveal_all(),
454 cx.tcx().intern_substs(&[main_ret_ty.into()]),
457 (start_fn, vec![bx.pointercast(rust_main, cx.type_ptr_to(cx.type_i8p())),
460 debug!("using user-defined start fn");
461 (rust_main, vec![arg_argc, arg_argv])
464 let result = bx.call(start_fn, &args, None);
465 let cast = bx.intcast(result, cx.type_int(), true);
470 /// Obtain the `argc` and `argv` values to pass to the rust start function.
471 fn get_argc_argv<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
472 cx: &'a Bx::CodegenCx,
474 ) -> (Bx::Value, Bx::Value)
476 if cx.sess().target.target.options.main_needs_argc_argv {
477 // Params from native `main()` used as args for rust start function
478 let param_argc = bx.get_param(0);
479 let param_argv = bx.get_param(1);
480 let arg_argc = bx.intcast(param_argc, cx.type_isize(), true);
481 let arg_argv = param_argv;
484 // The Rust start function doesn't need `argc` and `argv`, so just pass zeros.
485 let arg_argc = bx.const_int(cx.type_int(), 0);
486 let arg_argv = bx.const_null(cx.type_ptr_to(cx.type_i8p()));
491 pub const CODEGEN_WORKER_ID: usize = ::std::usize::MAX;
493 pub fn codegen_crate<B: ExtraBackendMethods>(
496 metadata: EncodedMetadata,
497 need_metadata_module: bool,
498 ) -> OngoingCodegen<B> {
499 check_for_rustc_errors_attr(tcx);
501 // Skip crate items and just output metadata in -Z no-codegen mode.
502 if tcx.sess.opts.debugging_opts.no_codegen ||
503 !tcx.sess.opts.output_types.should_codegen() {
504 let ongoing_codegen = start_async_codegen(backend, tcx, metadata, 1);
506 ongoing_codegen.codegen_finished(tcx);
508 assert_and_save_dep_graph(tcx);
510 ongoing_codegen.check_for_errors(tcx.sess);
512 return ongoing_codegen;
515 let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
517 // Run the monomorphization collector and partition the collected items into
519 let codegen_units = tcx.collect_and_partition_mono_items(LOCAL_CRATE).1;
520 let codegen_units = (*codegen_units).clone();
522 // Force all codegen_unit queries so they are already either red or green
523 // when compile_codegen_unit accesses them. We are not able to re-execute
524 // the codegen_unit query from just the DepNode, so an unknown color would
525 // lead to having to re-execute compile_codegen_unit, possibly
527 if tcx.dep_graph.is_fully_enabled() {
528 for cgu in &codegen_units {
529 tcx.codegen_unit(cgu.name());
533 let ongoing_codegen = start_async_codegen(backend.clone(), tcx, metadata, codegen_units.len());
534 let ongoing_codegen = AbortCodegenOnDrop::<B>(Some(ongoing_codegen));
536 // Codegen an allocator shim, if necessary.
538 // If the crate doesn't have an `allocator_kind` set then there's definitely
539 // no shim to generate. Otherwise we also check our dependency graph for all
540 // our output crate types. If anything there looks like its a `Dynamic`
541 // linkage, then it's already got an allocator shim and we'll be using that
542 // one instead. If nothing exists then it's our job to generate the
544 let any_dynamic_crate = tcx.dependency_formats(LOCAL_CRATE)
547 use rustc::middle::dependency_format::Linkage;
548 list.iter().any(|&linkage| linkage == Linkage::Dynamic)
550 let allocator_module = if any_dynamic_crate {
552 } else if let Some(kind) = *tcx.sess.allocator_kind.get() {
553 let llmod_id = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
555 Some("allocator")).to_string();
556 let mut modules = backend.new_metadata(tcx, &llmod_id);
557 time(tcx.sess, "write allocator module", || {
558 backend.codegen_allocator(tcx, &mut modules, kind)
563 module_llvm: modules,
564 kind: ModuleKind::Allocator,
570 if let Some(allocator_module) = allocator_module {
571 ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module);
574 if need_metadata_module {
575 // Codegen the encoded metadata.
576 let metadata_cgu_name = cgu_name_builder.build_cgu_name(LOCAL_CRATE,
578 Some("metadata")).to_string();
579 let mut metadata_llvm_module = backend.new_metadata(tcx, &metadata_cgu_name);
580 time(tcx.sess, "write compressed metadata", || {
581 backend.write_compressed_metadata(tcx, &ongoing_codegen.metadata,
582 &mut metadata_llvm_module);
585 let metadata_module = ModuleCodegen {
586 name: metadata_cgu_name,
587 module_llvm: metadata_llvm_module,
588 kind: ModuleKind::Metadata,
590 ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module);
593 // We sort the codegen units by size. This way we can schedule work for LLVM
594 // a bit more efficiently.
595 let codegen_units = {
596 let mut codegen_units = codegen_units;
597 codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate()));
601 let mut total_codegen_time = Duration::new(0, 0);
603 for cgu in codegen_units.into_iter() {
604 ongoing_codegen.wait_for_signal_to_codegen_item();
605 ongoing_codegen.check_for_errors(tcx.sess);
607 let cgu_reuse = determine_cgu_reuse(tcx, &cgu);
608 tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
612 let start_time = Instant::now();
613 backend.compile_codegen_unit(tcx, cgu.name(), &ongoing_codegen.coordinator_send);
614 total_codegen_time += start_time.elapsed();
617 CguReuse::PreLto => {
618 submit_pre_lto_module_to_llvm(&backend, tcx, &ongoing_codegen.coordinator_send,
619 CachedModuleCodegen {
620 name: cgu.name().to_string(),
621 source: cgu.work_product(tcx),
625 CguReuse::PostLto => {
626 submit_post_lto_module_to_llvm(&backend, &ongoing_codegen.coordinator_send,
627 CachedModuleCodegen {
628 name: cgu.name().to_string(),
629 source: cgu.work_product(tcx),
636 ongoing_codegen.codegen_finished(tcx);
638 // Since the main thread is sometimes blocked during codegen, we keep track
639 // -Ztime-passes output manually.
640 let time_depth = time_depth();
641 set_time_depth(time_depth + 1);
642 print_time_passes_entry(tcx.sess.time_passes(),
643 "codegen to LLVM IR",
645 set_time_depth(time_depth);
647 ::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
649 symbol_names_test::report_symbol_names(tcx);
651 ongoing_codegen.check_for_errors(tcx.sess);
653 assert_and_save_dep_graph(tcx);
654 ongoing_codegen.into_inner()
657 /// A curious wrapper structure whose only purpose is to call `codegen_aborted`
658 /// when it's dropped abnormally.
660 /// In the process of working on rust-lang/rust#55238 a mysterious segfault was
661 /// stumbled upon. The segfault was never reproduced locally, but it was
662 /// suspected to be related to the fact that codegen worker threads were
663 /// sticking around by the time the main thread was exiting, causing issues.
665 /// This structure is an attempt to fix that issue where the `codegen_aborted`
666 /// message will block until all workers have finished. This should ensure that
667 /// even if the main codegen thread panics we'll wait for pending work to
668 /// complete before returning from the main thread, hopefully avoiding
671 /// If you see this comment in the code, then it means that this workaround
672 /// worked! We may yet one day track down the mysterious cause of that
674 struct AbortCodegenOnDrop<B: ExtraBackendMethods>(Option<OngoingCodegen<B>>);
676 impl<B: ExtraBackendMethods> AbortCodegenOnDrop<B> {
677 fn into_inner(mut self) -> OngoingCodegen<B> {
678 self.0.take().unwrap()
682 impl<B: ExtraBackendMethods> Deref for AbortCodegenOnDrop<B> {
683 type Target = OngoingCodegen<B>;
685 fn deref(&self) -> &OngoingCodegen<B> {
686 self.0.as_ref().unwrap()
690 impl<B: ExtraBackendMethods> DerefMut for AbortCodegenOnDrop<B> {
691 fn deref_mut(&mut self) -> &mut OngoingCodegen<B> {
692 self.0.as_mut().unwrap()
696 impl<B: ExtraBackendMethods> Drop for AbortCodegenOnDrop<B> {
698 if let Some(codegen) = self.0.take() {
699 codegen.codegen_aborted();
704 fn assert_and_save_dep_graph(tcx: TyCtxt<'_>) {
707 || ::rustc_incremental::assert_dep_graph(tcx));
710 "serialize dep graph",
711 || ::rustc_incremental::save_dep_graph(tcx));
715 pub fn new(tcx: TyCtxt<'_>) -> CrateInfo {
716 let mut info = CrateInfo {
718 compiler_builtins: None,
719 profiler_runtime: None,
720 sanitizer_runtime: None,
721 is_no_builtins: Default::default(),
722 native_libraries: Default::default(),
723 used_libraries: tcx.native_libraries(LOCAL_CRATE),
724 link_args: tcx.link_args(LOCAL_CRATE),
725 crate_name: Default::default(),
726 used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic),
727 used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic),
728 used_crate_source: Default::default(),
729 lang_item_to_crate: Default::default(),
730 missing_lang_items: Default::default(),
731 dependency_formats: tcx.dependency_formats(LOCAL_CRATE),
733 let lang_items = tcx.lang_items();
735 let crates = tcx.crates();
737 let n_crates = crates.len();
738 info.native_libraries.reserve(n_crates);
739 info.crate_name.reserve(n_crates);
740 info.used_crate_source.reserve(n_crates);
741 info.missing_lang_items.reserve(n_crates);
743 for &cnum in crates.iter() {
744 info.native_libraries.insert(cnum, tcx.native_libraries(cnum));
745 info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string());
746 info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum));
747 if tcx.is_panic_runtime(cnum) {
748 info.panic_runtime = Some(cnum);
750 if tcx.is_compiler_builtins(cnum) {
751 info.compiler_builtins = Some(cnum);
753 if tcx.is_profiler_runtime(cnum) {
754 info.profiler_runtime = Some(cnum);
756 if tcx.is_sanitizer_runtime(cnum) {
757 info.sanitizer_runtime = Some(cnum);
759 if tcx.is_no_builtins(cnum) {
760 info.is_no_builtins.insert(cnum);
762 let missing = tcx.missing_lang_items(cnum);
763 for &item in missing.iter() {
764 if let Ok(id) = lang_items.require(item) {
765 info.lang_item_to_crate.insert(item, id.krate);
769 // No need to look for lang items that are whitelisted and don't
770 // actually need to exist.
771 let missing = missing.iter()
773 .filter(|&l| !weak_lang_items::whitelisted(tcx, l))
775 info.missing_lang_items.insert(cnum, missing);
782 pub fn provide_both(providers: &mut Providers<'_>) {
783 providers.backend_optimization_level = |tcx, cratenum| {
784 let for_speed = match tcx.sess.opts.optimize {
785 // If globally no optimisation is done, #[optimize] has no effect.
787 // This is done because if we ended up "upgrading" to `-O2` here, we’d populate the
788 // pass manager and it is likely that some module-wide passes (such as inliner or
789 // cross-function constant propagation) would ignore the `optnone` annotation we put
790 // on the functions, thus necessarily involving these functions into optimisations.
791 config::OptLevel::No => return config::OptLevel::No,
792 // If globally optimise-speed is already specified, just use that level.
793 config::OptLevel::Less => return config::OptLevel::Less,
794 config::OptLevel::Default => return config::OptLevel::Default,
795 config::OptLevel::Aggressive => return config::OptLevel::Aggressive,
796 // If globally optimize-for-size has been requested, use -O2 instead (if optimize(size)
798 config::OptLevel::Size => config::OptLevel::Default,
799 config::OptLevel::SizeMin => config::OptLevel::Default,
802 let (defids, _) = tcx.collect_and_partition_mono_items(cratenum);
804 let hir::CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
806 attr::OptimizeAttr::None => continue,
807 attr::OptimizeAttr::Size => continue,
808 attr::OptimizeAttr::Speed => {
813 return tcx.sess.opts.optimize;
816 providers.dllimport_foreign_items = |tcx, krate| {
817 let module_map = tcx.foreign_modules(krate);
818 let module_map = module_map.iter()
819 .map(|lib| (lib.def_id, lib))
820 .collect::<FxHashMap<_, _>>();
822 let dllimports = tcx.native_libraries(krate)
825 if lib.kind != cstore::NativeLibraryKind::NativeUnknown {
828 let cfg = match lib.cfg {
829 Some(ref cfg) => cfg,
832 attr::cfg_matches(cfg, &tcx.sess.parse_sess, None)
834 .filter_map(|lib| lib.foreign_module)
835 .map(|id| &module_map[&id])
836 .flat_map(|module| module.foreign_items.iter().cloned())
838 tcx.arena.alloc(dllimports)
841 providers.is_dllimport_foreign_item = |tcx, def_id| {
842 tcx.dllimport_foreign_items(def_id.krate).contains(&def_id)
846 fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
847 if !tcx.dep_graph.is_fully_enabled() {
851 let work_product_id = &cgu.work_product_id();
852 if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
853 // We don't have anything cached for this CGU. This can happen
854 // if the CGU did not exist in the previous session.
858 // Try to mark the CGU as green. If it we can do so, it means that nothing
859 // affecting the LLVM module has changed and we can re-use a cached version.
860 // If we compile with any kind of LTO, this means we can re-use the bitcode
861 // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
862 // know that later). If we are not doing LTO, there is only one optimized
863 // version of each module, so we re-use that.
864 let dep_node = cgu.codegen_dep_node(tcx);
865 assert!(!tcx.dep_graph.dep_node_exists(&dep_node),
866 "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
869 if tcx.dep_graph.try_mark_green(tcx, &dep_node).is_some() {
870 // We can re-use either the pre- or the post-thinlto state
871 if tcx.sess.lto() != Lto::No {