diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/base.rs')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/base.rs | 961 |
1 files changed, 961 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs new file mode 100644 index 000000000..a840b2709 --- /dev/null +++ b/compiler/rustc_codegen_ssa/src/base.rs @@ -0,0 +1,961 @@ +use crate::back::metadata::create_compressed_metadata_file; +use crate::back::write::{ + compute_per_cgu_lto_type, start_async_codegen, submit_codegened_module_to_llvm, + submit_post_lto_module_to_llvm, submit_pre_lto_module_to_llvm, ComputedLtoType, OngoingCodegen, +}; +use crate::common::{IntPredicate, RealPredicate, TypeKind}; +use crate::meth; +use crate::mir; +use crate::mir::operand::OperandValue; +use crate::mir::place::PlaceRef; +use crate::traits::*; +use crate::{CachedModuleCodegen, CompiledModule, CrateInfo, MemFlags, ModuleCodegen, ModuleKind}; + +use rustc_attr as attr; +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry}; + +use rustc_data_structures::sync::par_iter; +#[cfg(parallel_compiler)] +use rustc_data_structures::sync::ParallelIterator; +use rustc_hir as hir; +use rustc_hir::def_id::{DefId, LOCAL_CRATE}; +use rustc_hir::lang_items::LangItem; +use rustc_index::vec::Idx; +use rustc_metadata::EncodedMetadata; +use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs; +use rustc_middle::middle::exported_symbols; +use rustc_middle::middle::lang_items; +use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, MonoItem}; +use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout}; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; +use rustc_session::cgu_reuse_tracker::CguReuse; +use rustc_session::config::{self, CrateType, EntryFnType, OutputType}; +use rustc_session::Session; +use rustc_span::symbol::sym; +use rustc_span::{DebuggerVisualizerFile, DebuggerVisualizerType}; +use rustc_target::abi::{Align, VariantIdx}; + +use std::collections::BTreeSet; +use std::convert::TryFrom; +use std::time::{Duration, Instant}; + +use itertools::Itertools; + +pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind, signed: bool) -> IntPredicate { + match op { + hir::BinOpKind::Eq => IntPredicate::IntEQ, + hir::BinOpKind::Ne => IntPredicate::IntNE, + hir::BinOpKind::Lt => { + if signed { + IntPredicate::IntSLT + } else { + IntPredicate::IntULT + } + } + hir::BinOpKind::Le => { + if signed { + IntPredicate::IntSLE + } else { + IntPredicate::IntULE + } + } + hir::BinOpKind::Gt => { + if signed { + IntPredicate::IntSGT + } else { + IntPredicate::IntUGT + } + } + hir::BinOpKind::Ge => { + if signed { + IntPredicate::IntSGE + } else { + IntPredicate::IntUGE + } + } + op => bug!( + "comparison_op_to_icmp_predicate: expected comparison operator, \ + found {:?}", + op + ), + } +} + +pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> RealPredicate { + match op { + hir::BinOpKind::Eq => RealPredicate::RealOEQ, + hir::BinOpKind::Ne => RealPredicate::RealUNE, + hir::BinOpKind::Lt => RealPredicate::RealOLT, + hir::BinOpKind::Le => RealPredicate::RealOLE, + hir::BinOpKind::Gt => RealPredicate::RealOGT, + hir::BinOpKind::Ge => RealPredicate::RealOGE, + op => { + bug!( + "comparison_op_to_fcmp_predicate: expected comparison operator, \ + found {:?}", + op + ); + } + } +} + +pub fn compare_simd_types<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + lhs: Bx::Value, + rhs: Bx::Value, + t: Ty<'tcx>, + ret_ty: Bx::Type, + op: hir::BinOpKind, +) -> Bx::Value { + let signed = match t.kind() { + ty::Float(_) => { + let cmp = bin_op_to_fcmp_predicate(op); + let cmp = bx.fcmp(cmp, lhs, rhs); + return bx.sext(cmp, ret_ty); + } + ty::Uint(_) => false, + ty::Int(_) => true, + _ => bug!("compare_simd_types: invalid SIMD type"), + }; + + let cmp = bin_op_to_icmp_predicate(op, signed); + let cmp = bx.icmp(cmp, lhs, rhs); + // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension + // to get the correctly sized type. This will compile to a single instruction + // once the IR is converted to assembly if the SIMD instruction is supported + // by the target architecture. + bx.sext(cmp, ret_ty) +} + +/// Retrieves the information we are losing (making dynamic) in an unsizing +/// adjustment. +/// +/// The `old_info` argument is a bit odd. It is intended for use in an upcast, +/// where the new vtable for an object will be derived from the old one. +pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + source: Ty<'tcx>, + target: Ty<'tcx>, + old_info: Option<Bx::Value>, +) -> Bx::Value { + let cx = bx.cx(); + let (source, target) = + cx.tcx().struct_lockstep_tails_erasing_lifetimes(source, target, bx.param_env()); + match (source.kind(), target.kind()) { + (&ty::Array(_, len), &ty::Slice(_)) => { + cx.const_usize(len.eval_usize(cx.tcx(), ty::ParamEnv::reveal_all())) + } + (&ty::Dynamic(ref data_a, ..), &ty::Dynamic(ref data_b, ..)) => { + let old_info = + old_info.expect("unsized_info: missing old info for trait upcasting coercion"); + if data_a.principal_def_id() == data_b.principal_def_id() { + return old_info; + } + + // trait upcasting coercion + + let vptr_entry_idx = + cx.tcx().vtable_trait_upcasting_coercion_new_vptr_slot((source, target)); + + if let Some(entry_idx) = vptr_entry_idx { + let ptr_ty = cx.type_i8p(); + let ptr_align = cx.tcx().data_layout.pointer_align.abi; + let llvtable = bx.pointercast(old_info, bx.type_ptr_to(ptr_ty)); + let gep = bx.inbounds_gep( + ptr_ty, + llvtable, + &[bx.const_usize(u64::try_from(entry_idx).unwrap())], + ); + let new_vptr = bx.load(ptr_ty, gep, ptr_align); + bx.nonnull_metadata(new_vptr); + // VTable loads are invariant. + bx.set_invariant_load(new_vptr); + new_vptr + } else { + old_info + } + } + (_, &ty::Dynamic(ref data, ..)) => { + let vtable_ptr_ty = cx.scalar_pair_element_backend_type( + cx.layout_of(cx.tcx().mk_mut_ptr(target)), + 1, + true, + ); + cx.const_ptrcast(meth::get_vtable(cx, source, data.principal()), vtable_ptr_ty) + } + _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target), + } +} + +/// Coerces `src` to `dst_ty`. `src_ty` must be a pointer. +pub fn unsize_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + src: Bx::Value, + src_ty: Ty<'tcx>, + dst_ty: Ty<'tcx>, + old_info: Option<Bx::Value>, +) -> (Bx::Value, Bx::Value) { + debug!("unsize_ptr: {:?} => {:?}", src_ty, dst_ty); + match (src_ty.kind(), dst_ty.kind()) { + (&ty::Ref(_, a, _), &ty::Ref(_, b, _) | &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) + | (&ty::RawPtr(ty::TypeAndMut { ty: a, .. }), &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => { + assert_eq!(bx.cx().type_is_sized(a), old_info.is_none()); + let ptr_ty = bx.cx().type_ptr_to(bx.cx().backend_type(bx.cx().layout_of(b))); + (bx.pointercast(src, ptr_ty), unsized_info(bx, a, b, old_info)) + } + (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => { + assert_eq!(def_a, def_b); + let src_layout = bx.cx().layout_of(src_ty); + let dst_layout = bx.cx().layout_of(dst_ty); + if src_ty == dst_ty { + return (src, old_info.unwrap()); + } + let mut result = None; + for i in 0..src_layout.fields.count() { + let src_f = src_layout.field(bx.cx(), i); + if src_f.is_zst() { + continue; + } + + assert_eq!(src_layout.fields.offset(i).bytes(), 0); + assert_eq!(dst_layout.fields.offset(i).bytes(), 0); + assert_eq!(src_layout.size, src_f.size); + + let dst_f = dst_layout.field(bx.cx(), i); + assert_ne!(src_f.ty, dst_f.ty); + assert_eq!(result, None); + result = Some(unsize_ptr(bx, src, src_f.ty, dst_f.ty, old_info)); + } + let (lldata, llextra) = result.unwrap(); + let lldata_ty = bx.cx().scalar_pair_element_backend_type(dst_layout, 0, true); + let llextra_ty = bx.cx().scalar_pair_element_backend_type(dst_layout, 1, true); + // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types. + (bx.bitcast(lldata, lldata_ty), bx.bitcast(llextra, llextra_ty)) + } + _ => bug!("unsize_ptr: called on bad types"), + } +} + +/// Coerces `src`, which is a reference to a value of type `src_ty`, +/// to a value of type `dst_ty`, and stores the result in `dst`. +pub fn coerce_unsized_into<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + src: PlaceRef<'tcx, Bx::Value>, + dst: PlaceRef<'tcx, Bx::Value>, +) { + let src_ty = src.layout.ty; + let dst_ty = dst.layout.ty; + match (src_ty.kind(), dst_ty.kind()) { + (&ty::Ref(..), &ty::Ref(..) | &ty::RawPtr(..)) | (&ty::RawPtr(..), &ty::RawPtr(..)) => { + let (base, info) = match bx.load_operand(src).val { + OperandValue::Pair(base, info) => unsize_ptr(bx, base, src_ty, dst_ty, Some(info)), + OperandValue::Immediate(base) => unsize_ptr(bx, base, src_ty, dst_ty, None), + OperandValue::Ref(..) => bug!(), + }; + OperandValue::Pair(base, info).store(bx, dst); + } + + (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => { + assert_eq!(def_a, def_b); + + for i in 0..def_a.variant(VariantIdx::new(0)).fields.len() { + let src_f = src.project_field(bx, i); + let dst_f = dst.project_field(bx, i); + + if dst_f.layout.is_zst() { + continue; + } + + if src_f.layout.ty == dst_f.layout.ty { + memcpy_ty( + bx, + dst_f.llval, + dst_f.align, + src_f.llval, + src_f.align, + src_f.layout, + MemFlags::empty(), + ); + } else { + coerce_unsized_into(bx, src_f, dst_f); + } + } + } + _ => bug!("coerce_unsized_into: invalid coercion {:?} -> {:?}", src_ty, dst_ty,), + } +} + +pub fn cast_shift_expr_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + op: hir::BinOpKind, + lhs: Bx::Value, + rhs: Bx::Value, +) -> Bx::Value { + cast_shift_rhs(bx, op, lhs, rhs) +} + +fn cast_shift_rhs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + op: hir::BinOpKind, + lhs: Bx::Value, + rhs: Bx::Value, +) -> Bx::Value { + // Shifts may have any size int on the rhs + if op.is_shift() { + let mut rhs_llty = bx.cx().val_ty(rhs); + let mut lhs_llty = bx.cx().val_ty(lhs); + if bx.cx().type_kind(rhs_llty) == TypeKind::Vector { + rhs_llty = bx.cx().element_type(rhs_llty) + } + if bx.cx().type_kind(lhs_llty) == TypeKind::Vector { + lhs_llty = bx.cx().element_type(lhs_llty) + } + let rhs_sz = bx.cx().int_width(rhs_llty); + let lhs_sz = bx.cx().int_width(lhs_llty); + if lhs_sz < rhs_sz { + bx.trunc(rhs, lhs_llty) + } else if lhs_sz > rhs_sz { + // FIXME (#1877: If in the future shifting by negative + // values is no longer undefined then this is wrong. + bx.zext(rhs, lhs_llty) + } else { + rhs + } + } else { + rhs + } +} + +/// Returns `true` if this session's target will use SEH-based unwinding. +/// +/// This is only true for MSVC targets, and even then the 64-bit MSVC target +/// currently uses SEH-ish unwinding with DWARF info tables to the side (same as +/// 64-bit MinGW) instead of "full SEH". +pub fn wants_msvc_seh(sess: &Session) -> bool { + sess.target.is_like_msvc +} + +pub fn memcpy_ty<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + bx: &mut Bx, + dst: Bx::Value, + dst_align: Align, + src: Bx::Value, + src_align: Align, + layout: TyAndLayout<'tcx>, + flags: MemFlags, +) { + let size = layout.size.bytes(); + if size == 0 { + return; + } + + bx.memcpy(dst, dst_align, src, src_align, bx.cx().const_usize(size), flags); +} + +pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, + instance: Instance<'tcx>, +) { + // this is an info! to allow collecting monomorphization statistics + // and to allow finding the last function before LLVM aborts from + // release builds. + info!("codegen_instance({})", instance); + + mir::codegen_mir::<Bx>(cx, instance); +} + +/// Creates the `main` function which will initialize the rust runtime and call +/// users main function. +pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, +) -> Option<Bx::Function> { + let (main_def_id, entry_type) = cx.tcx().entry_fn(())?; + let main_is_local = main_def_id.is_local(); + let instance = Instance::mono(cx.tcx(), main_def_id); + + if main_is_local { + // We want to create the wrapper in the same codegen unit as Rust's main + // function. + if !cx.codegen_unit().contains_item(&MonoItem::Fn(instance)) { + return None; + } + } else if !cx.codegen_unit().is_primary() { + // We want to create the wrapper only when the codegen unit is the primary one + return None; + } + + let main_llfn = cx.get_fn_addr(instance); + + let use_start_lang_item = EntryFnType::Start != entry_type; + let entry_fn = create_entry_fn::<Bx>(cx, main_llfn, main_def_id, use_start_lang_item); + return Some(entry_fn); + + fn create_entry_fn<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, + rust_main: Bx::Value, + rust_main_def_id: DefId, + use_start_lang_item: bool, + ) -> Bx::Function { + // The entry function is either `int main(void)` or `int main(int argc, char **argv)`, + // depending on whether the target needs `argc` and `argv` to be passed in. + let llfty = if cx.sess().target.main_needs_argc_argv { + cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int()) + } else { + cx.type_func(&[], cx.type_int()) + }; + + let main_ret_ty = cx.tcx().fn_sig(rust_main_def_id).output(); + // Given that `main()` has no arguments, + // then its return type cannot have + // late-bound regions, since late-bound + // regions must appear in the argument + // listing. + let main_ret_ty = cx.tcx().normalize_erasing_regions( + ty::ParamEnv::reveal_all(), + main_ret_ty.no_bound_vars().unwrap(), + ); + + let Some(llfn) = cx.declare_c_main(llfty) else { + // FIXME: We should be smart and show a better diagnostic here. + let span = cx.tcx().def_span(rust_main_def_id); + cx.sess() + .struct_span_err(span, "entry symbol `main` declared multiple times") + .help("did you use `#[no_mangle]` on `fn main`? Use `#[start]` instead") + .emit(); + cx.sess().abort_if_errors(); + bug!(); + }; + + // `main` should respect same config for frame pointer elimination as rest of code + cx.set_frame_pointer_type(llfn); + cx.apply_target_cpu_attr(llfn); + + let llbb = Bx::append_block(&cx, llfn, "top"); + let mut bx = Bx::build(&cx, llbb); + + bx.insert_reference_to_gdb_debug_scripts_section_global(); + + let isize_ty = cx.type_isize(); + let i8pp_ty = cx.type_ptr_to(cx.type_i8p()); + let (arg_argc, arg_argv) = get_argc_argv(cx, &mut bx); + + let (start_fn, start_ty, args) = if use_start_lang_item { + let start_def_id = cx.tcx().require_lang_item(LangItem::Start, None); + let start_fn = cx.get_fn_addr( + ty::Instance::resolve( + cx.tcx(), + ty::ParamEnv::reveal_all(), + start_def_id, + cx.tcx().intern_substs(&[main_ret_ty.into()]), + ) + .unwrap() + .unwrap(), + ); + let start_ty = cx.type_func(&[cx.val_ty(rust_main), isize_ty, i8pp_ty], isize_ty); + (start_fn, start_ty, vec![rust_main, arg_argc, arg_argv]) + } else { + debug!("using user-defined start fn"); + let start_ty = cx.type_func(&[isize_ty, i8pp_ty], isize_ty); + (rust_main, start_ty, vec![arg_argc, arg_argv]) + }; + + let result = bx.call(start_ty, start_fn, &args, None); + let cast = bx.intcast(result, cx.type_int(), true); + bx.ret(cast); + + llfn + } +} + +/// Obtain the `argc` and `argv` values to pass to the rust start function. +fn get_argc_argv<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, + bx: &mut Bx, +) -> (Bx::Value, Bx::Value) { + if cx.sess().target.main_needs_argc_argv { + // Params from native `main()` used as args for rust start function + let param_argc = bx.get_param(0); + let param_argv = bx.get_param(1); + let arg_argc = bx.intcast(param_argc, cx.type_isize(), true); + let arg_argv = param_argv; + (arg_argc, arg_argv) + } else { + // The Rust start function doesn't need `argc` and `argv`, so just pass zeros. + let arg_argc = bx.const_int(cx.type_int(), 0); + let arg_argv = bx.const_null(cx.type_ptr_to(cx.type_i8p())); + (arg_argc, arg_argv) + } +} + +/// This function returns all of the debugger visualizers specified for the +/// current crate as well as all upstream crates transitively that match the +/// `visualizer_type` specified. +pub fn collect_debugger_visualizers_transitive( + tcx: TyCtxt<'_>, + visualizer_type: DebuggerVisualizerType, +) -> BTreeSet<DebuggerVisualizerFile> { + tcx.debugger_visualizers(LOCAL_CRATE) + .iter() + .chain( + tcx.crates(()) + .iter() + .filter(|&cnum| { + let used_crate_source = tcx.used_crate_source(*cnum); + used_crate_source.rlib.is_some() || used_crate_source.rmeta.is_some() + }) + .flat_map(|&cnum| tcx.debugger_visualizers(cnum)), + ) + .filter(|visualizer| visualizer.visualizer_type == visualizer_type) + .cloned() + .collect::<BTreeSet<_>>() +} + +pub fn codegen_crate<B: ExtraBackendMethods>( + backend: B, + tcx: TyCtxt<'_>, + target_cpu: String, + metadata: EncodedMetadata, + need_metadata_module: bool, +) -> OngoingCodegen<B> { + // Skip crate items and just output metadata in -Z no-codegen mode. + if tcx.sess.opts.unstable_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() { + let ongoing_codegen = start_async_codegen(backend, tcx, target_cpu, metadata, None, 1); + + ongoing_codegen.codegen_finished(tcx); + + ongoing_codegen.check_for_errors(tcx.sess); + + return ongoing_codegen; + } + + let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx); + + // Run the monomorphization collector and partition the collected items into + // codegen units. + let codegen_units = tcx.collect_and_partition_mono_items(()).1; + + // Force all codegen_unit queries so they are already either red or green + // when compile_codegen_unit accesses them. We are not able to re-execute + // the codegen_unit query from just the DepNode, so an unknown color would + // lead to having to re-execute compile_codegen_unit, possibly + // unnecessarily. + if tcx.dep_graph.is_fully_enabled() { + for cgu in codegen_units { + tcx.ensure().codegen_unit(cgu.name()); + } + } + + let metadata_module = if need_metadata_module { + // Emit compressed metadata object. + let metadata_cgu_name = + cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata")).to_string(); + tcx.sess.time("write_compressed_metadata", || { + let file_name = + tcx.output_filenames(()).temp_path(OutputType::Metadata, Some(&metadata_cgu_name)); + let data = create_compressed_metadata_file( + tcx.sess, + &metadata, + &exported_symbols::metadata_symbol_name(tcx), + ); + if let Err(err) = std::fs::write(&file_name, data) { + tcx.sess.fatal(&format!("error writing metadata object file: {}", err)); + } + Some(CompiledModule { + name: metadata_cgu_name, + kind: ModuleKind::Metadata, + object: Some(file_name), + dwarf_object: None, + bytecode: None, + }) + }) + } else { + None + }; + + let ongoing_codegen = start_async_codegen( + backend.clone(), + tcx, + target_cpu, + metadata, + metadata_module, + codegen_units.len(), + ); + + // Codegen an allocator shim, if necessary. + // + // If the crate doesn't have an `allocator_kind` set then there's definitely + // no shim to generate. Otherwise we also check our dependency graph for all + // our output crate types. If anything there looks like its a `Dynamic` + // linkage, then it's already got an allocator shim and we'll be using that + // one instead. If nothing exists then it's our job to generate the + // allocator! + let any_dynamic_crate = tcx.dependency_formats(()).iter().any(|(_, list)| { + use rustc_middle::middle::dependency_format::Linkage; + list.iter().any(|&linkage| linkage == Linkage::Dynamic) + }); + let allocator_module = if any_dynamic_crate { + None + } else if let Some(kind) = tcx.allocator_kind(()) { + let llmod_id = + cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).to_string(); + let module_llvm = tcx.sess.time("write_allocator_module", || { + backend.codegen_allocator(tcx, &llmod_id, kind, tcx.lang_items().oom().is_some()) + }); + + Some(ModuleCodegen { name: llmod_id, module_llvm, kind: ModuleKind::Allocator }) + } else { + None + }; + + if let Some(allocator_module) = allocator_module { + ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module); + } + + // For better throughput during parallel processing by LLVM, we used to sort + // CGUs largest to smallest. This would lead to better thread utilization + // by, for example, preventing a large CGU from being processed last and + // having only one LLVM thread working while the rest remained idle. + // + // However, this strategy would lead to high memory usage, as it meant the + // LLVM-IR for all of the largest CGUs would be resident in memory at once. + // + // Instead, we can compromise by ordering CGUs such that the largest and + // smallest are first, second largest and smallest are next, etc. If there + // are large size variations, this can reduce memory usage significantly. + let codegen_units: Vec<_> = { + let mut sorted_cgus = codegen_units.iter().collect::<Vec<_>>(); + sorted_cgus.sort_by_cached_key(|cgu| cgu.size_estimate()); + + let (first_half, second_half) = sorted_cgus.split_at(sorted_cgus.len() / 2); + second_half.iter().rev().interleave(first_half).copied().collect() + }; + + // Calculate the CGU reuse + let cgu_reuse = tcx.sess.time("find_cgu_reuse", || { + codegen_units.iter().map(|cgu| determine_cgu_reuse(tcx, &cgu)).collect::<Vec<_>>() + }); + + let mut total_codegen_time = Duration::new(0, 0); + let start_rss = tcx.sess.time_passes().then(|| get_resident_set_size()); + + // The non-parallel compiler can only translate codegen units to LLVM IR + // on a single thread, leading to a staircase effect where the N LLVM + // threads have to wait on the single codegen threads to generate work + // for them. The parallel compiler does not have this restriction, so + // we can pre-load the LLVM queue in parallel before handing off + // coordination to the OnGoingCodegen scheduler. + // + // This likely is a temporary measure. Once we don't have to support the + // non-parallel compiler anymore, we can compile CGUs end-to-end in + // parallel and get rid of the complicated scheduling logic. + let mut pre_compiled_cgus = if cfg!(parallel_compiler) { + tcx.sess.time("compile_first_CGU_batch", || { + // Try to find one CGU to compile per thread. + let cgus: Vec<_> = cgu_reuse + .iter() + .enumerate() + .filter(|&(_, reuse)| reuse == &CguReuse::No) + .take(tcx.sess.threads()) + .collect(); + + // Compile the found CGUs in parallel. + let start_time = Instant::now(); + + let pre_compiled_cgus = par_iter(cgus) + .map(|(i, _)| { + let module = backend.compile_codegen_unit(tcx, codegen_units[i].name()); + (i, module) + }) + .collect(); + + total_codegen_time += start_time.elapsed(); + + pre_compiled_cgus + }) + } else { + FxHashMap::default() + }; + + for (i, cgu) in codegen_units.iter().enumerate() { + ongoing_codegen.wait_for_signal_to_codegen_item(); + ongoing_codegen.check_for_errors(tcx.sess); + + let cgu_reuse = cgu_reuse[i]; + tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse); + + match cgu_reuse { + CguReuse::No => { + let (module, cost) = if let Some(cgu) = pre_compiled_cgus.remove(&i) { + cgu + } else { + let start_time = Instant::now(); + let module = backend.compile_codegen_unit(tcx, cgu.name()); + total_codegen_time += start_time.elapsed(); + module + }; + // This will unwind if there are errors, which triggers our `AbortCodegenOnDrop` + // guard. Unfortunately, just skipping the `submit_codegened_module_to_llvm` makes + // compilation hang on post-monomorphization errors. + tcx.sess.abort_if_errors(); + + submit_codegened_module_to_llvm( + &backend, + &ongoing_codegen.coordinator.sender, + module, + cost, + ); + false + } + CguReuse::PreLto => { + submit_pre_lto_module_to_llvm( + &backend, + tcx, + &ongoing_codegen.coordinator.sender, + CachedModuleCodegen { + name: cgu.name().to_string(), + source: cgu.previous_work_product(tcx), + }, + ); + true + } + CguReuse::PostLto => { + submit_post_lto_module_to_llvm( + &backend, + &ongoing_codegen.coordinator.sender, + CachedModuleCodegen { + name: cgu.name().to_string(), + source: cgu.previous_work_product(tcx), + }, + ); + true + } + }; + } + + ongoing_codegen.codegen_finished(tcx); + + // Since the main thread is sometimes blocked during codegen, we keep track + // -Ztime-passes output manually. + if tcx.sess.time_passes() { + let end_rss = get_resident_set_size(); + + print_time_passes_entry( + "codegen_to_LLVM_IR", + total_codegen_time, + start_rss.unwrap(), + end_rss, + ); + } + + ongoing_codegen.check_for_errors(tcx.sess); + ongoing_codegen +} + +impl CrateInfo { + pub fn new(tcx: TyCtxt<'_>, target_cpu: String) -> CrateInfo { + let exported_symbols = tcx + .sess + .crate_types() + .iter() + .map(|&c| (c, crate::back::linker::exported_symbols(tcx, c))) + .collect(); + let linked_symbols = tcx + .sess + .crate_types() + .iter() + .map(|&c| (c, crate::back::linker::linked_symbols(tcx, c))) + .collect(); + let local_crate_name = tcx.crate_name(LOCAL_CRATE); + let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID); + let subsystem = tcx.sess.first_attr_value_str_by_name(crate_attrs, sym::windows_subsystem); + let windows_subsystem = subsystem.map(|subsystem| { + if subsystem != sym::windows && subsystem != sym::console { + tcx.sess.fatal(&format!( + "invalid windows subsystem `{}`, only \ + `windows` and `console` are allowed", + subsystem + )); + } + subsystem.to_string() + }); + + // This list is used when generating the command line to pass through to + // system linker. The linker expects undefined symbols on the left of the + // command line to be defined in libraries on the right, not the other way + // around. For more info, see some comments in the add_used_library function + // below. + // + // In order to get this left-to-right dependency ordering, we use the reverse + // postorder of all crates putting the leaves at the right-most positions. + let used_crates = tcx + .postorder_cnums(()) + .iter() + .rev() + .copied() + .filter(|&cnum| !tcx.dep_kind(cnum).macros_only()) + .collect(); + + let mut info = CrateInfo { + target_cpu, + exported_symbols, + linked_symbols, + local_crate_name, + compiler_builtins: None, + profiler_runtime: None, + is_no_builtins: Default::default(), + native_libraries: Default::default(), + used_libraries: tcx.native_libraries(LOCAL_CRATE).iter().map(Into::into).collect(), + crate_name: Default::default(), + used_crates, + used_crate_source: Default::default(), + lang_item_to_crate: Default::default(), + missing_lang_items: Default::default(), + dependency_formats: tcx.dependency_formats(()).clone(), + windows_subsystem, + natvis_debugger_visualizers: Default::default(), + }; + let lang_items = tcx.lang_items(); + + let crates = tcx.crates(()); + + let n_crates = crates.len(); + info.native_libraries.reserve(n_crates); + info.crate_name.reserve(n_crates); + info.used_crate_source.reserve(n_crates); + info.missing_lang_items.reserve(n_crates); + + for &cnum in crates.iter() { + info.native_libraries + .insert(cnum, tcx.native_libraries(cnum).iter().map(Into::into).collect()); + info.crate_name.insert(cnum, tcx.crate_name(cnum)); + + let used_crate_source = tcx.used_crate_source(cnum); + info.used_crate_source.insert(cnum, used_crate_source.clone()); + if tcx.is_compiler_builtins(cnum) { + info.compiler_builtins = Some(cnum); + } + if tcx.is_profiler_runtime(cnum) { + info.profiler_runtime = Some(cnum); + } + if tcx.is_no_builtins(cnum) { + info.is_no_builtins.insert(cnum); + } + let missing = tcx.missing_lang_items(cnum); + for &item in missing.iter() { + if let Ok(id) = lang_items.require(item) { + info.lang_item_to_crate.insert(item, id.krate); + } + } + + // No need to look for lang items that don't actually need to exist. + let missing = + missing.iter().cloned().filter(|&l| lang_items::required(tcx, l)).collect(); + info.missing_lang_items.insert(cnum, missing); + } + + let embed_visualizers = tcx.sess.crate_types().iter().any(|&crate_type| match crate_type { + CrateType::Executable | CrateType::Dylib | CrateType::Cdylib => { + // These are crate types for which we invoke the linker and can embed + // NatVis visualizers. + true + } + CrateType::ProcMacro => { + // We could embed NatVis for proc macro crates too (to improve the debugging + // experience for them) but it does not seem like a good default, since + // this is a rare use case and we don't want to slow down the common case. + false + } + CrateType::Staticlib | CrateType::Rlib => { + // We don't invoke the linker for these, so we don't need to collect the NatVis for them. + false + } + }); + + if tcx.sess.target.is_like_msvc && embed_visualizers { + info.natvis_debugger_visualizers = + collect_debugger_visualizers_transitive(tcx, DebuggerVisualizerType::Natvis); + } + + info + } +} + +pub fn provide(providers: &mut Providers) { + providers.backend_optimization_level = |tcx, cratenum| { + let for_speed = match tcx.sess.opts.optimize { + // If globally no optimisation is done, #[optimize] has no effect. + // + // This is done because if we ended up "upgrading" to `-O2` here, we’d populate the + // pass manager and it is likely that some module-wide passes (such as inliner or + // cross-function constant propagation) would ignore the `optnone` annotation we put + // on the functions, thus necessarily involving these functions into optimisations. + config::OptLevel::No => return config::OptLevel::No, + // If globally optimise-speed is already specified, just use that level. + config::OptLevel::Less => return config::OptLevel::Less, + config::OptLevel::Default => return config::OptLevel::Default, + config::OptLevel::Aggressive => return config::OptLevel::Aggressive, + // If globally optimize-for-size has been requested, use -O2 instead (if optimize(size) + // are present). + config::OptLevel::Size => config::OptLevel::Default, + config::OptLevel::SizeMin => config::OptLevel::Default, + }; + + let (defids, _) = tcx.collect_and_partition_mono_items(cratenum); + for id in &*defids { + let CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id); + match optimize { + attr::OptimizeAttr::None => continue, + attr::OptimizeAttr::Size => continue, + attr::OptimizeAttr::Speed => { + return for_speed; + } + } + } + tcx.sess.opts.optimize + }; +} + +fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse { + if !tcx.dep_graph.is_fully_enabled() { + return CguReuse::No; + } + + let work_product_id = &cgu.work_product_id(); + if tcx.dep_graph.previous_work_product(work_product_id).is_none() { + // We don't have anything cached for this CGU. This can happen + // if the CGU did not exist in the previous session. + return CguReuse::No; + } + + // Try to mark the CGU as green. If it we can do so, it means that nothing + // affecting the LLVM module has changed and we can re-use a cached version. + // If we compile with any kind of LTO, this means we can re-use the bitcode + // of the Pre-LTO stage (possibly also the Post-LTO version but we'll only + // know that later). If we are not doing LTO, there is only one optimized + // version of each module, so we re-use that. + let dep_node = cgu.codegen_dep_node(tcx); + assert!( + !tcx.dep_graph.dep_node_exists(&dep_node), + "CompileCodegenUnit dep-node for CGU `{}` already exists before marking.", + cgu.name() + ); + + if tcx.try_mark_green(&dep_node) { + // We can re-use either the pre- or the post-thinlto state. If no LTO is + // being performed then we can use post-LTO artifacts, otherwise we must + // reuse pre-LTO artifacts + match compute_per_cgu_lto_type( + &tcx.sess.lto(), + &tcx.sess.opts, + &tcx.sess.crate_types(), + ModuleKind::Regular, + ) { + ComputedLtoType::No => CguReuse::PostLto, + _ => CguReuse::PreLto, + } + } else { + CguReuse::No + } +} |