// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Codegen the completed AST to the LLVM IR. //! //! Some functions here, such as codegen_block and codegen_expr, return a value -- //! the result of the codegen to LLVM -- while others, such as codegen_fn //! and mono_item, are called only for the side effect of adding a //! particular definition to the LLVM IR output we're producing. //! //! Hopefully useful general knowledge about codegen: //! //! * There's no way to find out the Ty type of a Value. Doing so //! would be "trying to get the eggs out of an omelette" (credit: //! pcwalton). You can, instead, find out its llvm::Type by calling val_ty, //! but one llvm::Type corresponds to many `Ty`s; for instance, tup(int, int, //! int) and rec(x=int, y=int, z=int) will have the same llvm::Type. use super::ModuleLlvm; use super::ModuleCodegen; use super::ModuleKind; use super::CachedModuleCodegen; use abi; use back::write::{self, OngoingCodegen}; use llvm::{self, TypeKind, get_param}; use metadata; use rustc::dep_graph::cgu_reuse_tracker::CguReuse; use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE}; use rustc::middle::lang_items::StartFnLangItem; use rustc::middle::weak_lang_items; use rustc::mir::mono::{Linkage, Visibility, Stats, CodegenUnitNameBuilder}; use rustc::middle::cstore::{EncodedMetadata}; use rustc::ty::{self, Ty, TyCtxt}; use rustc::ty::layout::{self, Align, TyLayout, LayoutOf, VariantIdx}; use rustc::ty::query::Providers; use rustc::middle::cstore::{self, LinkagePreference}; use rustc::middle::exported_symbols; use rustc::util::common::{time, print_time_passes_entry}; use rustc::util::profiling::ProfileCategory; use rustc::session::config::{self, DebugInfo, EntryFnType, Lto}; use rustc::session::Session; use rustc_incremental; use allocator; use mir::place::PlaceRef; use attributes; use builder::{Builder, MemFlags}; use callee; use common::{C_bool, C_bytes_in_context, C_usize}; use rustc_mir::monomorphize::item::DefPathBasedNames; use common::{C_struct_in_context, C_array, val_ty}; use consts; use context::CodegenCx; use debuginfo; use declare; use meth; use mir; use monomorphize::Instance; use monomorphize::partitioning::{CodegenUnit, CodegenUnitExt}; use rustc_codegen_utils::symbol_names_test; use time_graph; use mono_item::{MonoItem, MonoItemExt}; use type_::Type; use type_of::LayoutLlvmExt; use rustc::util::nodemap::FxHashMap; use CrateInfo; use rustc_data_structures::small_c_str::SmallCStr; use rustc_data_structures::sync::Lrc; use rustc_data_structures::indexed_vec::Idx; use std::any::Any; use std::cmp; use std::ffi::CString; use std::ops::{Deref, DerefMut}; use std::sync::mpsc; use std::time::{Instant, Duration}; use syntax_pos::Span; use syntax_pos::symbol::InternedString; use syntax::attr; use rustc::hir::{self, CodegenFnAttrs}; use value::Value; use mir::operand::OperandValue; use rustc_codegen_utils::check_for_rustc_errors_attr; pub struct StatRecorder<'a, 'll: 'a, 'tcx: 'll> { cx: &'a CodegenCx<'ll, 'tcx>, name: Option, istart: usize, } impl StatRecorder<'a, 'll, 'tcx> { pub fn new(cx: &'a CodegenCx<'ll, 'tcx>, name: String) -> Self { let istart = cx.stats.borrow().n_llvm_insns; StatRecorder { cx, name: Some(name), istart, } } } impl Drop for StatRecorder<'a, 'll, 'tcx> { fn drop(&mut self) { if self.cx.sess().codegen_stats() { let mut stats = self.cx.stats.borrow_mut(); let iend = stats.n_llvm_insns; stats.fn_stats.push((self.name.take().unwrap(), iend - self.istart)); stats.n_fns += 1; // Reset LLVM insn count to avoid compound costs. stats.n_llvm_insns = self.istart; } } } pub fn bin_op_to_icmp_predicate(op: hir::BinOpKind, signed: bool) -> llvm::IntPredicate { match op { hir::BinOpKind::Eq => llvm::IntEQ, hir::BinOpKind::Ne => llvm::IntNE, hir::BinOpKind::Lt => if signed { llvm::IntSLT } else { llvm::IntULT }, hir::BinOpKind::Le => if signed { llvm::IntSLE } else { llvm::IntULE }, hir::BinOpKind::Gt => if signed { llvm::IntSGT } else { llvm::IntUGT }, hir::BinOpKind::Ge => if signed { llvm::IntSGE } else { llvm::IntUGE }, op => { bug!("comparison_op_to_icmp_predicate: expected comparison operator, \ found {:?}", op) } } } pub fn bin_op_to_fcmp_predicate(op: hir::BinOpKind) -> llvm::RealPredicate { match op { hir::BinOpKind::Eq => llvm::RealOEQ, hir::BinOpKind::Ne => llvm::RealUNE, hir::BinOpKind::Lt => llvm::RealOLT, hir::BinOpKind::Le => llvm::RealOLE, hir::BinOpKind::Gt => llvm::RealOGT, hir::BinOpKind::Ge => llvm::RealOGE, op => { bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \ found {:?}", op); } } } pub fn compare_simd_types( bx: &Builder<'a, 'll, 'tcx>, lhs: &'ll Value, rhs: &'ll Value, t: Ty<'tcx>, ret_ty: &'ll Type, op: hir::BinOpKind ) -> &'ll Value { let signed = match t.sty { ty::Float(_) => { let cmp = bin_op_to_fcmp_predicate(op); return bx.sext(bx.fcmp(cmp, lhs, rhs), ret_ty); }, ty::Uint(_) => false, ty::Int(_) => true, _ => bug!("compare_simd_types: invalid SIMD type"), }; let cmp = bin_op_to_icmp_predicate(op, signed); // 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(bx.icmp(cmp, lhs, rhs), ret_ty) } /// Retrieve the information we are losing (making dynamic) in an unsizing /// adjustment. /// /// The `old_info` argument is a bit funny. 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( cx: &CodegenCx<'ll, 'tcx>, source: Ty<'tcx>, target: Ty<'tcx>, old_info: Option<&'ll Value>, ) -> &'ll Value { let (source, target) = cx.tcx.struct_lockstep_tails(source, target); match (&source.sty, &target.sty) { (&ty::Array(_, len), &ty::Slice(_)) => { C_usize(cx, len.unwrap_usize(cx.tcx)) } (&ty::Dynamic(..), &ty::Dynamic(..)) => { // For now, upcasts are limited to changes in marker // traits, and hence never actually require an actual // change to the vtable. old_info.expect("unsized_info: missing old info for trait upcast") } (_, &ty::Dynamic(ref data, ..)) => { let vtable_ptr = cx.layout_of(cx.tcx.mk_mut_ptr(target)) .field(cx, abi::FAT_PTR_EXTRA); consts::ptrcast(meth::get_vtable(cx, source, data.principal()), vtable_ptr.llvm_type(cx)) } _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target), } } /// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer. pub fn unsize_thin_ptr( bx: &Builder<'a, 'll, 'tcx>, src: &'ll Value, src_ty: Ty<'tcx>, dst_ty: Ty<'tcx> ) -> (&'ll Value, &'ll Value) { debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty); match (&src_ty.sty, &dst_ty.sty) { (&ty::Ref(_, a, _), &ty::Ref(_, b, _)) | (&ty::Ref(_, a, _), &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) | (&ty::RawPtr(ty::TypeAndMut { ty: a, .. }), &ty::RawPtr(ty::TypeAndMut { ty: b, .. })) => { assert!(bx.cx.type_is_sized(a)); let ptr_ty = bx.cx.layout_of(b).llvm_type(bx.cx).ptr_to(); (bx.pointercast(src, ptr_ty), unsized_info(bx.cx, a, b, None)) } (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => { let (a, b) = (src_ty.boxed_ty(), dst_ty.boxed_ty()); assert!(bx.cx.type_is_sized(a)); let ptr_ty = bx.cx.layout_of(b).llvm_type(bx.cx).ptr_to(); (bx.pointercast(src, ptr_ty), unsized_info(bx.cx, a, b, None)) } (&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); let mut result = None; for i in 0..src_layout.fields.count() { let src_f = src_layout.field(bx.cx, i); assert_eq!(src_layout.fields.offset(i).bytes(), 0); assert_eq!(dst_layout.fields.offset(i).bytes(), 0); if src_f.is_zst() { continue; } 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_thin_ptr(bx, src, src_f.ty, dst_f.ty)); } let (lldata, llextra) = result.unwrap(); // HACK(eddyb) have to bitcast pointers until LLVM removes pointee types. (bx.bitcast(lldata, dst_layout.scalar_pair_element_llvm_type(bx.cx, 0, true)), bx.bitcast(llextra, dst_layout.scalar_pair_element_llvm_type(bx.cx, 1, true))) } _ => bug!("unsize_thin_ptr: called on bad types"), } } /// Coerce `src`, which is a reference to a value of type `src_ty`, /// to a value of type `dst_ty` and store the result in `dst` pub fn coerce_unsized_into( bx: &Builder<'a, 'll, 'tcx>, src: PlaceRef<'ll, 'tcx>, dst: PlaceRef<'ll, 'tcx> ) { let src_ty = src.layout.ty; let dst_ty = dst.layout.ty; let coerce_ptr = || { let (base, info) = match src.load(bx).val { OperandValue::Pair(base, info) => { // fat-ptr to fat-ptr unsize preserves the vtable // i.e. &'a fmt::Debug+Send => &'a fmt::Debug // So we need to pointercast the base to ensure // the types match up. let thin_ptr = dst.layout.field(bx.cx, abi::FAT_PTR_ADDR); (bx.pointercast(base, thin_ptr.llvm_type(bx.cx)), info) } OperandValue::Immediate(base) => { unsize_thin_ptr(bx, base, src_ty, dst_ty) } OperandValue::Ref(..) => bug!() }; OperandValue::Pair(base, info).store(bx, dst); }; match (&src_ty.sty, &dst_ty.sty) { (&ty::Ref(..), &ty::Ref(..)) | (&ty::Ref(..), &ty::RawPtr(..)) | (&ty::RawPtr(..), &ty::RawPtr(..)) => { coerce_ptr() } (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) if def_a.is_box() && def_b.is_box() => { coerce_ptr() } (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => { assert_eq!(def_a, def_b); for i in 0..def_a.variants[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( cx: &Builder<'_, 'll, '_>, op: hir::BinOpKind, lhs: &'ll Value, rhs: &'ll Value ) -> &'ll Value { cast_shift_rhs(op, lhs, rhs, |a, b| cx.trunc(a, b), |a, b| cx.zext(a, b)) } fn cast_shift_rhs<'ll, F, G>(op: hir::BinOpKind, lhs: &'ll Value, rhs: &'ll Value, trunc: F, zext: G) -> &'ll Value where F: FnOnce(&'ll Value, &'ll Type) -> &'ll Value, G: FnOnce(&'ll Value, &'ll Type) -> &'ll Value { // Shifts may have any size int on the rhs if op.is_shift() { let mut rhs_llty = val_ty(rhs); let mut lhs_llty = val_ty(lhs); if rhs_llty.kind() == TypeKind::Vector { rhs_llty = rhs_llty.element_type() } if lhs_llty.kind() == TypeKind::Vector { lhs_llty = lhs_llty.element_type() } let rhs_sz = rhs_llty.int_width(); let lhs_sz = lhs_llty.int_width(); if lhs_sz < rhs_sz { 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. zext(rhs, lhs_llty) } else { rhs } } else { rhs } } /// Returns whether 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.target.options.is_like_msvc } pub fn call_assume(bx: &Builder<'_, 'll, '_>, val: &'ll Value) { let assume_intrinsic = bx.cx.get_intrinsic("llvm.assume"); bx.call(assume_intrinsic, &[val], None); } pub fn from_immediate(bx: &Builder<'_, 'll, '_>, val: &'ll Value) -> &'ll Value { if val_ty(val) == Type::i1(bx.cx) { bx.zext(val, Type::i8(bx.cx)) } else { val } } pub fn to_immediate( bx: &Builder<'_, 'll, '_>, val: &'ll Value, layout: layout::TyLayout, ) -> &'ll Value { if let layout::Abi::Scalar(ref scalar) = layout.abi { return to_immediate_scalar(bx, val, scalar); } val } pub fn to_immediate_scalar( bx: &Builder<'_, 'll, '_>, val: &'ll Value, scalar: &layout::Scalar, ) -> &'ll Value { if scalar.is_bool() { return bx.trunc(val, Type::i1(bx.cx)); } val } pub fn call_memcpy( bx: &Builder<'_, 'll, '_>, dst: &'ll Value, dst_align: Align, src: &'ll Value, src_align: Align, n_bytes: &'ll Value, flags: MemFlags, ) { if flags.contains(MemFlags::NONTEMPORAL) { // HACK(nox): This is inefficient but there is no nontemporal memcpy. let val = bx.load(src, src_align); let ptr = bx.pointercast(dst, val_ty(val).ptr_to()); bx.store_with_flags(val, ptr, dst_align, flags); return; } let cx = bx.cx; let src_ptr = bx.pointercast(src, Type::i8p(cx)); let dst_ptr = bx.pointercast(dst, Type::i8p(cx)); let size = bx.intcast(n_bytes, cx.isize_ty, false); let volatile = flags.contains(MemFlags::VOLATILE); bx.memcpy(dst_ptr, dst_align.abi(), src_ptr, src_align.abi(), size, volatile); } pub fn memcpy_ty( bx: &Builder<'_, 'll, 'tcx>, dst: &'ll Value, dst_align: Align, src: &'ll Value, src_align: Align, layout: TyLayout<'tcx>, flags: MemFlags, ) { let size = layout.size.bytes(); if size == 0 { return; } call_memcpy(bx, dst, dst_align, src, src_align, C_usize(bx.cx, size), flags); } pub fn call_memset( bx: &Builder<'_, 'll, '_>, ptr: &'ll Value, fill_byte: &'ll Value, size: &'ll Value, align: &'ll Value, volatile: bool, ) -> &'ll Value { let ptr_width = &bx.cx.sess().target.target.target_pointer_width; let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width); let llintrinsicfn = bx.cx.get_intrinsic(&intrinsic_key); let volatile = C_bool(bx.cx, volatile); bx.call(llintrinsicfn, &[ptr, fill_byte, size, align, volatile], None) } pub fn codegen_instance<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>, instance: Instance<'tcx>) { let _s = if cx.sess().codegen_stats() { let mut instance_name = String::new(); DefPathBasedNames::new(cx.tcx, true, true) .push_def_path(instance.def_id(), &mut instance_name); Some(StatRecorder::new(cx, instance_name)) } else { None }; // 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); let sig = instance.fn_sig(cx.tcx); let sig = cx.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig); let lldecl = cx.instances.borrow().get(&instance).cloned().unwrap_or_else(|| bug!("Instance `{:?}` not already declared", instance)); cx.stats.borrow_mut().n_closures += 1; let mir = cx.tcx.instance_mir(instance.def); mir::codegen_mir(cx, lldecl, &mir, instance, sig); } pub fn set_link_section(llval: &Value, attrs: &CodegenFnAttrs) { let sect = match attrs.link_section { Some(name) => name, None => return, }; unsafe { let buf = SmallCStr::new(§.as_str()); llvm::LLVMSetSection(llval, buf.as_ptr()); } } /// Create the `main` function which will initialize the rust runtime and call /// users main function. fn maybe_create_entry_wrapper(cx: &CodegenCx) { let (main_def_id, span) = match *cx.sess().entry_fn.borrow() { Some((id, span, _)) => { (cx.tcx.hir.local_def_id(id), span) } None => return, }; let instance = Instance::mono(cx.tcx, main_def_id); if !cx.codegen_unit.contains_item(&MonoItem::Fn(instance)) { // We want to create the wrapper in the same codegen unit as Rust's main // function. return; } let main_llfn = callee::get_fn(cx, instance); let et = cx.sess().entry_fn.get().map(|e| e.2); match et { Some(EntryFnType::Main) => create_entry_fn(cx, span, main_llfn, main_def_id, true), Some(EntryFnType::Start) => create_entry_fn(cx, span, main_llfn, main_def_id, false), None => {} // Do nothing. } fn create_entry_fn( cx: &CodegenCx<'ll, '_>, sp: Span, rust_main: &'ll Value, rust_main_def_id: DefId, use_start_lang_item: bool, ) { let llfty = Type::func(&[Type::c_int(cx), Type::i8p(cx).ptr_to()], Type::c_int(cx)); 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.erase_regions( &main_ret_ty.no_bound_vars().unwrap(), ); if declare::get_defined_value(cx, "main").is_some() { // FIXME: We should be smart and show a better diagnostic here. cx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times") .help("did you use #[no_mangle] on `fn main`? Use #[start] instead") .emit(); cx.sess().abort_if_errors(); bug!(); } let llfn = declare::declare_cfn(cx, "main", llfty); // `main` should respect same config for frame pointer elimination as rest of code attributes::set_frame_pointer_elimination(cx, llfn); attributes::apply_target_cpu_attr(cx, llfn); let bx = Builder::new_block(cx, llfn, "top"); debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(&bx); // Params from native main() used as args for rust start function let param_argc = get_param(llfn, 0); let param_argv = get_param(llfn, 1); let arg_argc = bx.intcast(param_argc, cx.isize_ty, true); let arg_argv = param_argv; let (start_fn, args) = if use_start_lang_item { let start_def_id = cx.tcx.require_lang_item(StartFnLangItem); let start_fn = callee::resolve_and_get_fn( cx, start_def_id, cx.tcx.intern_substs(&[main_ret_ty.into()]), ); (start_fn, vec![bx.pointercast(rust_main, Type::i8p(cx).ptr_to()), arg_argc, arg_argv]) } else { debug!("using user-defined start fn"); (rust_main, vec![arg_argc, arg_argv]) }; let result = bx.call(start_fn, &args, None); bx.ret(bx.intcast(result, Type::c_int(cx), true)); } } fn write_metadata<'a, 'gcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, llvm_module: &ModuleLlvm) -> EncodedMetadata { use std::io::Write; use flate2::Compression; use flate2::write::DeflateEncoder; let (metadata_llcx, metadata_llmod) = (&*llvm_module.llcx, llvm_module.llmod()); #[derive(PartialEq, Eq, PartialOrd, Ord)] enum MetadataKind { None, Uncompressed, Compressed } let kind = tcx.sess.crate_types.borrow().iter().map(|ty| { match *ty { config::CrateType::Executable | config::CrateType::Staticlib | config::CrateType::Cdylib => MetadataKind::None, config::CrateType::Rlib => MetadataKind::Uncompressed, config::CrateType::Dylib | config::CrateType::ProcMacro => MetadataKind::Compressed, } }).max().unwrap_or(MetadataKind::None); if kind == MetadataKind::None { return EncodedMetadata::new(); } let metadata = tcx.encode_metadata(); if kind == MetadataKind::Uncompressed { return metadata; } assert!(kind == MetadataKind::Compressed); let mut compressed = tcx.metadata_encoding_version(); DeflateEncoder::new(&mut compressed, Compression::fast()) .write_all(&metadata.raw_data).unwrap(); let llmeta = C_bytes_in_context(metadata_llcx, &compressed); let llconst = C_struct_in_context(metadata_llcx, &[llmeta], false); let name = exported_symbols::metadata_symbol_name(tcx); let buf = CString::new(name).unwrap(); let llglobal = unsafe { llvm::LLVMAddGlobal(metadata_llmod, val_ty(llconst), buf.as_ptr()) }; unsafe { llvm::LLVMSetInitializer(llglobal, llconst); let section_name = metadata::metadata_section_name(&tcx.sess.target.target); let name = SmallCStr::new(section_name); llvm::LLVMSetSection(llglobal, name.as_ptr()); // Also generate a .section directive to force no // flags, at least for ELF outputs, so that the // metadata doesn't get loaded into memory. let directive = format!(".section {}", section_name); let directive = CString::new(directive).unwrap(); llvm::LLVMSetModuleInlineAsm(metadata_llmod, directive.as_ptr()) } return metadata; } pub struct ValueIter<'ll> { cur: Option<&'ll Value>, step: unsafe extern "C" fn(&'ll Value) -> Option<&'ll Value>, } impl Iterator for ValueIter<'ll> { type Item = &'ll Value; fn next(&mut self) -> Option<&'ll Value> { let old = self.cur; if let Some(old) = old { self.cur = unsafe { (self.step)(old) }; } old } } pub fn iter_globals(llmod: &'ll llvm::Module) -> ValueIter<'ll> { unsafe { ValueIter { cur: llvm::LLVMGetFirstGlobal(llmod), step: llvm::LLVMGetNextGlobal, } } } fn determine_cgu_reuse<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, '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.dep_graph.try_mark_green(tcx, &dep_node).is_some() { // We can re-use either the pre- or the post-thinlto state if tcx.sess.lto() != Lto::No { CguReuse::PreLto } else { CguReuse::PostLto } } else { CguReuse::No } } pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, rx: mpsc::Receiver>) -> OngoingCodegen { check_for_rustc_errors_attr(tcx); let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx); // Codegen the metadata. tcx.sess.profiler(|p| p.start_activity(ProfileCategory::Codegen)); let metadata_cgu_name = cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata")).as_str() .to_string(); let metadata_llvm_module = ModuleLlvm::new(tcx.sess, &metadata_cgu_name); let metadata = time(tcx.sess, "write metadata", || { write_metadata(tcx, &metadata_llvm_module) }); tcx.sess.profiler(|p| p.end_activity(ProfileCategory::Codegen)); let metadata_module = ModuleCodegen { name: metadata_cgu_name, module_llvm: metadata_llvm_module, kind: ModuleKind::Metadata, }; let time_graph = if tcx.sess.opts.debugging_opts.codegen_time_graph { Some(time_graph::TimeGraph::new()) } else { None }; // Skip crate items and just output metadata in -Z no-codegen mode. if tcx.sess.opts.debugging_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() { let ongoing_codegen = write::start_async_codegen( tcx, time_graph, metadata, rx, 1); ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module); ongoing_codegen.codegen_finished(tcx); assert_and_save_dep_graph(tcx); ongoing_codegen.check_for_errors(tcx.sess); return ongoing_codegen; } // Run the monomorphization collector and partition the collected items into // codegen units. let codegen_units = tcx.collect_and_partition_mono_items(LOCAL_CRATE).1; let codegen_units = (*codegen_units).clone(); // 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.codegen_unit(cgu.name().clone()); } } let ongoing_codegen = write::start_async_codegen( tcx, time_graph.clone(), metadata, rx, codegen_units.len()); let ongoing_codegen = AbortCodegenOnDrop(Some(ongoing_codegen)); // 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.sess.dependency_formats.borrow() .iter() .any(|(_, list)| { use rustc::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.sess.allocator_kind.get() { let llmod_id = cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).as_str() .to_string(); let modules = ModuleLlvm::new(tcx.sess, &llmod_id); time(tcx.sess, "write allocator module", || { unsafe { allocator::codegen(tcx, &modules, kind) } }); Some(ModuleCodegen { name: llmod_id, module_llvm: modules, kind: ModuleKind::Allocator, }) } else { None }; if let Some(allocator_module) = allocator_module { ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, allocator_module); } ongoing_codegen.submit_pre_codegened_module_to_llvm(tcx, metadata_module); // We sort the codegen units by size. This way we can schedule work for LLVM // a bit more efficiently. let codegen_units = { let mut codegen_units = codegen_units; codegen_units.sort_by_cached_key(|cgu| cmp::Reverse(cgu.size_estimate())); codegen_units }; let mut total_codegen_time = Duration::new(0, 0); let mut all_stats = Stats::default(); for cgu in codegen_units.into_iter() { ongoing_codegen.wait_for_signal_to_codegen_item(); ongoing_codegen.check_for_errors(tcx.sess); let cgu_reuse = determine_cgu_reuse(tcx, &cgu); tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse); match cgu_reuse { CguReuse::No => { let _timing_guard = time_graph.as_ref().map(|time_graph| { time_graph.start(write::CODEGEN_WORKER_TIMELINE, write::CODEGEN_WORK_PACKAGE_KIND, &format!("codegen {}", cgu.name())) }); let start_time = Instant::now(); let stats = compile_codegen_unit(tcx, *cgu.name()); all_stats.extend(stats); total_codegen_time += start_time.elapsed(); false } CguReuse::PreLto => { write::submit_pre_lto_module_to_llvm(tcx, CachedModuleCodegen { name: cgu.name().to_string(), source: cgu.work_product(tcx), }); true } CguReuse::PostLto => { write::submit_post_lto_module_to_llvm(tcx, CachedModuleCodegen { name: cgu.name().to_string(), source: cgu.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. print_time_passes_entry(tcx.sess.time_passes(), "codegen to LLVM IR", total_codegen_time); rustc_incremental::assert_module_sources::assert_module_sources(tcx); symbol_names_test::report_symbol_names(tcx); if tcx.sess.codegen_stats() { println!("--- codegen stats ---"); println!("n_glues_created: {}", all_stats.n_glues_created); println!("n_null_glues: {}", all_stats.n_null_glues); println!("n_real_glues: {}", all_stats.n_real_glues); println!("n_fns: {}", all_stats.n_fns); println!("n_inlines: {}", all_stats.n_inlines); println!("n_closures: {}", all_stats.n_closures); println!("fn stats:"); all_stats.fn_stats.sort_by_key(|&(_, insns)| insns); for &(ref name, insns) in all_stats.fn_stats.iter() { println!("{} insns, {}", insns, *name); } } if tcx.sess.count_llvm_insns() { for (k, v) in all_stats.llvm_insns.iter() { println!("{:7} {}", *v, *k); } } ongoing_codegen.check_for_errors(tcx.sess); assert_and_save_dep_graph(tcx); ongoing_codegen.into_inner() } /// A curious wrapper structure whose only purpose is to call `codegen_aborted` /// when it's dropped abnormally. /// /// In the process of working on rust-lang/rust#55238 a mysterious segfault was /// stumbled upon. The segfault was never reproduced locally, but it was /// suspected to be related to the fact that codegen worker threads were /// sticking around by the time the main thread was exiting, causing issues. /// /// This structure is an attempt to fix that issue where the `codegen_aborted` /// message will block until all workers have finished. This should ensure that /// even if the main codegen thread panics we'll wait for pending work to /// complete before returning from the main thread, hopefully avoiding /// segfaults. /// /// If you see this comment in the code, then it means that this workaround /// worked! We may yet one day track down the mysterious cause of that /// segfault... struct AbortCodegenOnDrop(Option); impl AbortCodegenOnDrop { fn into_inner(mut self) -> OngoingCodegen { self.0.take().unwrap() } } impl Deref for AbortCodegenOnDrop { type Target = OngoingCodegen; fn deref(&self) -> &OngoingCodegen { self.0.as_ref().unwrap() } } impl DerefMut for AbortCodegenOnDrop { fn deref_mut(&mut self) -> &mut OngoingCodegen { self.0.as_mut().unwrap() } } impl Drop for AbortCodegenOnDrop { fn drop(&mut self) { if let Some(codegen) = self.0.take() { codegen.codegen_aborted(); } } } fn assert_and_save_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) { time(tcx.sess, "assert dep graph", || rustc_incremental::assert_dep_graph(tcx)); time(tcx.sess, "serialize dep graph", || rustc_incremental::save_dep_graph(tcx)); } impl CrateInfo { pub fn new(tcx: TyCtxt) -> CrateInfo { let mut info = CrateInfo { panic_runtime: None, compiler_builtins: None, profiler_runtime: None, sanitizer_runtime: None, is_no_builtins: Default::default(), native_libraries: Default::default(), used_libraries: tcx.native_libraries(LOCAL_CRATE), link_args: tcx.link_args(LOCAL_CRATE), crate_name: Default::default(), used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic), used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic), used_crate_source: Default::default(), wasm_imports: Default::default(), lang_item_to_crate: Default::default(), missing_lang_items: Default::default(), }; let lang_items = tcx.lang_items(); let load_wasm_items = tcx.sess.crate_types.borrow() .iter() .any(|c| *c != config::CrateType::Rlib) && tcx.sess.opts.target_triple.triple() == "wasm32-unknown-unknown"; if load_wasm_items { info.load_wasm_imports(tcx, LOCAL_CRATE); } 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)); info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string()); info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum)); if tcx.is_panic_runtime(cnum) { info.panic_runtime = Some(cnum); } 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_sanitizer_runtime(cnum) { info.sanitizer_runtime = Some(cnum); } if tcx.is_no_builtins(cnum) { info.is_no_builtins.insert(cnum); } if load_wasm_items { info.load_wasm_imports(tcx, 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 are whitelisted and don't // actually need to exist. let missing = missing.iter() .cloned() .filter(|&l| !weak_lang_items::whitelisted(tcx, l)) .collect(); info.missing_lang_items.insert(cnum, missing); } return info } fn load_wasm_imports(&mut self, tcx: TyCtxt, cnum: CrateNum) { self.wasm_imports.extend(tcx.wasm_import_module_map(cnum).iter().map(|(&id, module)| { let instance = Instance::mono(tcx, id); let import_name = tcx.symbol_name(instance); (import_name.to_string(), module.clone()) })); } } fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, cgu_name: InternedString) -> Stats { let start_time = Instant::now(); let dep_node = tcx.codegen_unit(cgu_name).codegen_dep_node(tcx); let ((stats, module), _) = tcx.dep_graph.with_task(dep_node, tcx, cgu_name, module_codegen); let time_to_codegen = start_time.elapsed(); // We assume that the cost to run LLVM on a CGU is proportional to // the time we needed for codegenning it. let cost = time_to_codegen.as_secs() * 1_000_000_000 + time_to_codegen.subsec_nanos() as u64; write::submit_codegened_module_to_llvm(tcx, module, cost); return stats; fn module_codegen<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, cgu_name: InternedString) -> (Stats, ModuleCodegen) { let cgu = tcx.codegen_unit(cgu_name); // Instantiate monomorphizations without filling out definitions yet... let llvm_module = ModuleLlvm::new(tcx.sess, &cgu_name.as_str()); let stats = { let cx = CodegenCx::new(tcx, cgu, &llvm_module); let mono_items = cx.codegen_unit .items_in_deterministic_order(cx.tcx); for &(mono_item, (linkage, visibility)) in &mono_items { mono_item.predefine(&cx, linkage, visibility); } // ... and now that we have everything pre-defined, fill out those definitions. for &(mono_item, _) in &mono_items { mono_item.define(&cx); } // If this codegen unit contains the main function, also create the // wrapper here maybe_create_entry_wrapper(&cx); // Run replace-all-uses-with for statics that need it for &(old_g, new_g) in cx.statics_to_rauw.borrow().iter() { unsafe { let bitcast = llvm::LLVMConstPointerCast(new_g, val_ty(old_g)); llvm::LLVMReplaceAllUsesWith(old_g, bitcast); llvm::LLVMDeleteGlobal(old_g); } } // Create the llvm.used variable // This variable has type [N x i8*] and is stored in the llvm.metadata section if !cx.used_statics.borrow().is_empty() { let name = const_cstr!("llvm.used"); let section = const_cstr!("llvm.metadata"); let array = C_array(Type::i8(&cx).ptr_to(), &*cx.used_statics.borrow()); unsafe { let g = llvm::LLVMAddGlobal(cx.llmod, val_ty(array), name.as_ptr()); llvm::LLVMSetInitializer(g, array); llvm::LLVMRustSetLinkage(g, llvm::Linkage::AppendingLinkage); llvm::LLVMSetSection(g, section.as_ptr()); } } // Finalize debuginfo if cx.sess().opts.debuginfo != DebugInfo::None { debuginfo::finalize(&cx); } cx.stats.into_inner() }; (stats, ModuleCodegen { name: cgu_name.to_string(), module_llvm: llvm_module, kind: ModuleKind::Regular, }) } } pub fn provide_both(providers: &mut Providers) { providers.dllimport_foreign_items = |tcx, krate| { let module_map = tcx.foreign_modules(krate); let module_map = module_map.iter() .map(|lib| (lib.def_id, lib)) .collect::>(); let dllimports = tcx.native_libraries(krate) .iter() .filter(|lib| { if lib.kind != cstore::NativeLibraryKind::NativeUnknown { return false } let cfg = match lib.cfg { Some(ref cfg) => cfg, None => return true, }; attr::cfg_matches(cfg, &tcx.sess.parse_sess, None) }) .filter_map(|lib| lib.foreign_module) .map(|id| &module_map[&id]) .flat_map(|module| module.foreign_items.iter().cloned()) .collect(); Lrc::new(dllimports) }; providers.is_dllimport_foreign_item = |tcx, def_id| { tcx.dllimport_foreign_items(def_id.krate).contains(&def_id) }; } pub fn linkage_to_llvm(linkage: Linkage) -> llvm::Linkage { match linkage { Linkage::External => llvm::Linkage::ExternalLinkage, Linkage::AvailableExternally => llvm::Linkage::AvailableExternallyLinkage, Linkage::LinkOnceAny => llvm::Linkage::LinkOnceAnyLinkage, Linkage::LinkOnceODR => llvm::Linkage::LinkOnceODRLinkage, Linkage::WeakAny => llvm::Linkage::WeakAnyLinkage, Linkage::WeakODR => llvm::Linkage::WeakODRLinkage, Linkage::Appending => llvm::Linkage::AppendingLinkage, Linkage::Internal => llvm::Linkage::InternalLinkage, Linkage::Private => llvm::Linkage::PrivateLinkage, Linkage::ExternalWeak => llvm::Linkage::ExternalWeakLinkage, Linkage::Common => llvm::Linkage::CommonLinkage, } } pub fn visibility_to_llvm(linkage: Visibility) -> llvm::Visibility { match linkage { Visibility::Default => llvm::Visibility::Default, Visibility::Hidden => llvm::Visibility::Hidden, Visibility::Protected => llvm::Visibility::Protected, } } // FIXME(mw): Anything that is produced via DepGraph::with_task() must implement // the HashStable trait. Normally DepGraph::with_task() calls are // hidden behind queries, but CGU creation is a special case in two // ways: (1) it's not a query and (2) CGU are output nodes, so their // Fingerprints are not actually needed. It remains to be clarified // how exactly this case will be handled in the red/green system but // for now we content ourselves with providing a no-op HashStable // implementation for CGUs. mod temp_stable_hash_impls { use rustc_data_structures::stable_hasher::{StableHasherResult, StableHasher, HashStable}; use ModuleCodegen; impl HashStable for ModuleCodegen { fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) { // do nothing } } }