// 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. //! Translate the completed AST to the LLVM IR. //! //! Some functions here, such as trans_block and trans_expr, return a value -- //! the result of the translation to LLVM -- while others, such as trans_fn //! and trans_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 trans: //! //! * There's no way to find out the Ty type of a ValueRef. Doing so //! would be "trying to get the eggs out of an omelette" (credit: //! pcwalton). You can, instead, find out its TypeRef by calling val_ty, //! but one TypeRef corresponds to many `Ty`s; for instance, tup(int, int, //! int) and rec(x=int, y=int, z=int) will have the same TypeRef. use super::ModuleLlvm; use super::ModuleSource; use super::ModuleTranslation; use super::ModuleKind; use assert_module_sources; use back::link; use back::symbol_export; use back::write::{self, OngoingCrateTranslation, create_target_machine}; use llvm::{ContextRef, ModuleRef, ValueRef, Vector, get_param}; use llvm; use metadata; use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE}; use rustc::middle::lang_items::StartFnLangItem; use rustc::middle::trans::{Linkage, Visibility, Stats}; use rustc::middle::cstore::{EncodedMetadata, EncodedMetadataHashes}; use rustc::ty::{self, Ty, TyCtxt}; use rustc::ty::maps::Providers; use rustc::dep_graph::{DepNode, DepKind, DepConstructor}; use rustc::middle::cstore::{self, LinkMeta, LinkagePreference}; use rustc::util::common::{time, print_time_passes_entry}; use rustc::session::config::{self, NoDebugInfo}; use rustc::session::Session; use rustc_incremental; use abi; use allocator; use mir::lvalue::LvalueRef; use attributes; use builder::Builder; use callee; use common::{C_bool, C_bytes_in_context, C_i32, C_usize}; use collector::{self, TransItemCollectionMode}; use common::{C_struct_in_context, C_u64, C_undef, C_array}; use common::CrateContext; use common::{type_is_zero_size, val_ty}; use common; use consts; use context::{self, LocalCrateContext, SharedCrateContext}; use debuginfo; use declare; use machine; use meth; use mir; use monomorphize::{self, Instance}; use partitioning::{self, PartitioningStrategy, CodegenUnit, CodegenUnitExt}; use symbol_names_test; use time_graph; use trans_item::{TransItem, BaseTransItemExt, TransItemExt, DefPathBasedNames}; use type_::Type; use type_of; use value::Value; use rustc::util::nodemap::{NodeSet, FxHashMap, FxHashSet, DefIdSet}; use CrateInfo; use std::any::Any; use std::ffi::CString; use std::str; use std::sync::Arc; use std::time::{Instant, Duration}; use std::i32; use std::sync::mpsc; use syntax_pos::Span; use syntax_pos::symbol::InternedString; use syntax::attr; use rustc::hir; use syntax::ast; use mir::lvalue::Alignment; pub use rustc_trans_utils::{find_exported_symbols, check_for_rustc_errors_attr}; pub use rustc_trans_utils::trans_item::linkage_by_name; pub struct StatRecorder<'a, 'tcx: 'a> { ccx: &'a CrateContext<'a, 'tcx>, name: Option, istart: usize, } impl<'a, 'tcx> StatRecorder<'a, 'tcx> { pub fn new(ccx: &'a CrateContext<'a, 'tcx>, name: String) -> StatRecorder<'a, 'tcx> { let istart = ccx.stats().borrow().n_llvm_insns; StatRecorder { ccx, name: Some(name), istart, } } } impl<'a, 'tcx> Drop for StatRecorder<'a, 'tcx> { fn drop(&mut self) { if self.ccx.sess().trans_stats() { let mut stats = self.ccx.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 get_meta(bcx: &Builder, fat_ptr: ValueRef) -> ValueRef { bcx.struct_gep(fat_ptr, abi::FAT_PTR_EXTRA) } pub fn get_dataptr(bcx: &Builder, fat_ptr: ValueRef) -> ValueRef { bcx.struct_gep(fat_ptr, abi::FAT_PTR_ADDR) } pub fn bin_op_to_icmp_predicate(op: hir::BinOp_, signed: bool) -> llvm::IntPredicate { match op { hir::BiEq => llvm::IntEQ, hir::BiNe => llvm::IntNE, hir::BiLt => if signed { llvm::IntSLT } else { llvm::IntULT }, hir::BiLe => if signed { llvm::IntSLE } else { llvm::IntULE }, hir::BiGt => if signed { llvm::IntSGT } else { llvm::IntUGT }, hir::BiGe => 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::BinOp_) -> llvm::RealPredicate { match op { hir::BiEq => llvm::RealOEQ, hir::BiNe => llvm::RealUNE, hir::BiLt => llvm::RealOLT, hir::BiLe => llvm::RealOLE, hir::BiGt => llvm::RealOGT, hir::BiGe => llvm::RealOGE, op => { bug!("comparison_op_to_fcmp_predicate: expected comparison operator, \ found {:?}", op); } } } pub fn compare_simd_types<'a, 'tcx>( bcx: &Builder<'a, 'tcx>, lhs: ValueRef, rhs: ValueRef, t: Ty<'tcx>, ret_ty: Type, op: hir::BinOp_ ) -> ValueRef { let signed = match t.sty { ty::TyFloat(_) => { let cmp = bin_op_to_fcmp_predicate(op); return bcx.sext(bcx.fcmp(cmp, lhs, rhs), ret_ty); }, ty::TyUint(_) => false, ty::TyInt(_) => 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. bcx.sext(bcx.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<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>, source: Ty<'tcx>, target: Ty<'tcx>, old_info: Option) -> ValueRef { let (source, target) = ccx.tcx().struct_lockstep_tails(source, target); match (&source.sty, &target.sty) { (&ty::TyArray(_, len), &ty::TySlice(_)) => { C_usize(ccx, len.val.to_const_int().unwrap().to_u64().unwrap()) } (&ty::TyDynamic(..), &ty::TyDynamic(..)) => { // 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::TyDynamic(ref data, ..)) => { consts::ptrcast(meth::get_vtable(ccx, source, data.principal()), Type::vtable_ptr(ccx)) } _ => bug!("unsized_info: invalid unsizing {:?} -> {:?}", source, target), } } /// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer. pub fn unsize_thin_ptr<'a, 'tcx>( bcx: &Builder<'a, 'tcx>, src: ValueRef, src_ty: Ty<'tcx>, dst_ty: Ty<'tcx> ) -> (ValueRef, ValueRef) { debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty); match (&src_ty.sty, &dst_ty.sty) { (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }), &ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) | (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }), &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) | (&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }), &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => { assert!(bcx.ccx.shared().type_is_sized(a)); let ptr_ty = type_of::in_memory_type_of(bcx.ccx, b).ptr_to(); (bcx.pointercast(src, ptr_ty), unsized_info(bcx.ccx, a, b, None)) } (&ty::TyAdt(def_a, _), &ty::TyAdt(def_b, _)) if def_a.is_box() && def_b.is_box() => { let (a, b) = (src_ty.boxed_ty(), dst_ty.boxed_ty()); assert!(bcx.ccx.shared().type_is_sized(a)); let ptr_ty = type_of::in_memory_type_of(bcx.ccx, b).ptr_to(); (bcx.pointercast(src, ptr_ty), unsized_info(bcx.ccx, a, b, None)) } _ => 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<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, src: &LvalueRef<'tcx>, dst: &LvalueRef<'tcx>) { let src_ty = src.ty.to_ty(bcx.tcx()); let dst_ty = dst.ty.to_ty(bcx.tcx()); let coerce_ptr = || { let (base, info) = if common::type_is_fat_ptr(bcx.ccx, src_ty) { // 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 (base, info) = load_fat_ptr(bcx, src.llval, src.alignment, src_ty); let llcast_ty = type_of::fat_ptr_base_ty(bcx.ccx, dst_ty); let base = bcx.pointercast(base, llcast_ty); (base, info) } else { let base = load_ty(bcx, src.llval, src.alignment, src_ty); unsize_thin_ptr(bcx, base, src_ty, dst_ty) }; store_fat_ptr(bcx, base, info, dst.llval, dst.alignment, dst_ty); }; match (&src_ty.sty, &dst_ty.sty) { (&ty::TyRef(..), &ty::TyRef(..)) | (&ty::TyRef(..), &ty::TyRawPtr(..)) | (&ty::TyRawPtr(..), &ty::TyRawPtr(..)) => { coerce_ptr() } (&ty::TyAdt(def_a, _), &ty::TyAdt(def_b, _)) if def_a.is_box() && def_b.is_box() => { coerce_ptr() } (&ty::TyAdt(def_a, substs_a), &ty::TyAdt(def_b, substs_b)) => { assert_eq!(def_a, def_b); let src_fields = def_a.variants[0].fields.iter().map(|f| { monomorphize::field_ty(bcx.tcx(), substs_a, f) }); let dst_fields = def_b.variants[0].fields.iter().map(|f| { monomorphize::field_ty(bcx.tcx(), substs_b, f) }); let iter = src_fields.zip(dst_fields).enumerate(); for (i, (src_fty, dst_fty)) in iter { if type_is_zero_size(bcx.ccx, dst_fty) { continue; } let (src_f, src_f_align) = src.trans_field_ptr(bcx, i); let (dst_f, dst_f_align) = dst.trans_field_ptr(bcx, i); if src_fty == dst_fty { memcpy_ty(bcx, dst_f, src_f, src_fty, None); } else { coerce_unsized_into( bcx, &LvalueRef::new_sized_ty(src_f, src_fty, src_f_align), &LvalueRef::new_sized_ty(dst_f, dst_fty, dst_f_align) ); } } } _ => bug!("coerce_unsized_into: invalid coercion {:?} -> {:?}", src_ty, dst_ty), } } pub fn cast_shift_expr_rhs( cx: &Builder, op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef ) -> ValueRef { cast_shift_rhs(op, lhs, rhs, |a, b| cx.trunc(a, b), |a, b| cx.zext(a, b)) } pub fn cast_shift_const_rhs(op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef { cast_shift_rhs(op, lhs, rhs, |a, b| unsafe { llvm::LLVMConstTrunc(a, b.to_ref()) }, |a, b| unsafe { llvm::LLVMConstZExt(a, b.to_ref()) }) } fn cast_shift_rhs(op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef, trunc: F, zext: G) -> ValueRef where F: FnOnce(ValueRef, Type) -> ValueRef, G: FnOnce(ValueRef, Type) -> ValueRef { // 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() == Vector { rhs_llty = rhs_llty.element_type() } if lhs_llty.kind() == 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 shifting by negative // values becomes not 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<'a, 'tcx>(b: &Builder<'a, 'tcx>, val: ValueRef) { let assume_intrinsic = b.ccx.get_intrinsic("llvm.assume"); b.call(assume_intrinsic, &[val], None); } /// Helper for loading values from memory. Does the necessary conversion if the in-memory type /// differs from the type used for SSA values. Also handles various special cases where the type /// gives us better information about what we are loading. pub fn load_ty<'a, 'tcx>(b: &Builder<'a, 'tcx>, ptr: ValueRef, alignment: Alignment, t: Ty<'tcx>) -> ValueRef { let ccx = b.ccx; if type_is_zero_size(ccx, t) { return C_undef(type_of::type_of(ccx, t)); } unsafe { let global = llvm::LLVMIsAGlobalVariable(ptr); if !global.is_null() && llvm::LLVMIsGlobalConstant(global) == llvm::True { let val = llvm::LLVMGetInitializer(global); if !val.is_null() { if t.is_bool() { return llvm::LLVMConstTrunc(val, Type::i1(ccx).to_ref()); } return val; } } } if t.is_bool() { b.trunc(b.load_range_assert(ptr, 0, 2, llvm::False, alignment.to_align()), Type::i1(ccx)) } else if t.is_char() { // a char is a Unicode codepoint, and so takes values from 0 // to 0x10FFFF inclusive only. b.load_range_assert(ptr, 0, 0x10FFFF + 1, llvm::False, alignment.to_align()) } else if (t.is_region_ptr() || t.is_box() || t.is_fn()) && !common::type_is_fat_ptr(ccx, t) { b.load_nonnull(ptr, alignment.to_align()) } else { b.load(ptr, alignment.to_align()) } } /// Helper for storing values in memory. Does the necessary conversion if the in-memory type /// differs from the type used for SSA values. pub fn store_ty<'a, 'tcx>(cx: &Builder<'a, 'tcx>, v: ValueRef, dst: ValueRef, dst_align: Alignment, t: Ty<'tcx>) { debug!("store_ty: {:?} : {:?} <- {:?}", Value(dst), t, Value(v)); if common::type_is_fat_ptr(cx.ccx, t) { let lladdr = cx.extract_value(v, abi::FAT_PTR_ADDR); let llextra = cx.extract_value(v, abi::FAT_PTR_EXTRA); store_fat_ptr(cx, lladdr, llextra, dst, dst_align, t); } else { cx.store(from_immediate(cx, v), dst, dst_align.to_align()); } } pub fn store_fat_ptr<'a, 'tcx>(cx: &Builder<'a, 'tcx>, data: ValueRef, extra: ValueRef, dst: ValueRef, dst_align: Alignment, _ty: Ty<'tcx>) { // FIXME: emit metadata cx.store(data, get_dataptr(cx, dst), dst_align.to_align()); cx.store(extra, get_meta(cx, dst), dst_align.to_align()); } pub fn load_fat_ptr<'a, 'tcx>( b: &Builder<'a, 'tcx>, src: ValueRef, alignment: Alignment, t: Ty<'tcx> ) -> (ValueRef, ValueRef) { let ptr = get_dataptr(b, src); let ptr = if t.is_region_ptr() || t.is_box() { b.load_nonnull(ptr, alignment.to_align()) } else { b.load(ptr, alignment.to_align()) }; let meta = get_meta(b, src); let meta_ty = val_ty(meta); // If the 'meta' field is a pointer, it's a vtable, so use load_nonnull // instead let meta = if meta_ty.element_type().kind() == llvm::TypeKind::Pointer { b.load_nonnull(meta, None) } else { b.load(meta, None) }; (ptr, meta) } pub fn from_immediate(bcx: &Builder, val: ValueRef) -> ValueRef { if val_ty(val) == Type::i1(bcx.ccx) { bcx.zext(val, Type::i8(bcx.ccx)) } else { val } } pub fn to_immediate(bcx: &Builder, val: ValueRef, ty: Ty) -> ValueRef { if ty.is_bool() { bcx.trunc(val, Type::i1(bcx.ccx)) } else { val } } pub enum Lifetime { Start, End } impl Lifetime { // If LLVM lifetime intrinsic support is enabled (i.e. optimizations // on), and `ptr` is nonzero-sized, then extracts the size of `ptr` // and the intrinsic for `lt` and passes them to `emit`, which is in // charge of generating code to call the passed intrinsic on whatever // block of generated code is targeted for the intrinsic. // // If LLVM lifetime intrinsic support is disabled (i.e. optimizations // off) or `ptr` is zero-sized, then no-op (does not call `emit`). pub fn call(self, b: &Builder, ptr: ValueRef) { if b.ccx.sess().opts.optimize == config::OptLevel::No { return; } let size = machine::llsize_of_alloc(b.ccx, val_ty(ptr).element_type()); if size == 0 { return; } let lifetime_intrinsic = b.ccx.get_intrinsic(match self { Lifetime::Start => "llvm.lifetime.start", Lifetime::End => "llvm.lifetime.end" }); let ptr = b.pointercast(ptr, Type::i8p(b.ccx)); b.call(lifetime_intrinsic, &[C_u64(b.ccx, size), ptr], None); } } pub fn call_memcpy<'a, 'tcx>(b: &Builder<'a, 'tcx>, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) { let ccx = b.ccx; let ptr_width = &ccx.sess().target.target.target_pointer_width; let key = format!("llvm.memcpy.p0i8.p0i8.i{}", ptr_width); let memcpy = ccx.get_intrinsic(&key); let src_ptr = b.pointercast(src, Type::i8p(ccx)); let dst_ptr = b.pointercast(dst, Type::i8p(ccx)); let size = b.intcast(n_bytes, ccx.isize_ty(), false); let align = C_i32(ccx, align as i32); let volatile = C_bool(ccx, false); b.call(memcpy, &[dst_ptr, src_ptr, size, align, volatile], None); } pub fn memcpy_ty<'a, 'tcx>( bcx: &Builder<'a, 'tcx>, dst: ValueRef, src: ValueRef, t: Ty<'tcx>, align: Option, ) { let ccx = bcx.ccx; let size = ccx.size_of(t); if size == 0 { return; } let align = align.unwrap_or_else(|| ccx.align_of(t)); call_memcpy(bcx, dst, src, C_usize(ccx, size), align); } pub fn call_memset<'a, 'tcx>(b: &Builder<'a, 'tcx>, ptr: ValueRef, fill_byte: ValueRef, size: ValueRef, align: ValueRef, volatile: bool) -> ValueRef { let ptr_width = &b.ccx.sess().target.target.target_pointer_width; let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width); let llintrinsicfn = b.ccx.get_intrinsic(&intrinsic_key); let volatile = C_bool(b.ccx, volatile); b.call(llintrinsicfn, &[ptr, fill_byte, size, align, volatile], None) } pub fn trans_instance<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, instance: Instance<'tcx>) { let _s = if ccx.sess().trans_stats() { let mut instance_name = String::new(); DefPathBasedNames::new(ccx.tcx(), true, true) .push_def_path(instance.def_id(), &mut instance_name); Some(StatRecorder::new(ccx, 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!("trans_instance({})", instance); let fn_ty = common::instance_ty(ccx.tcx(), &instance); let sig = common::ty_fn_sig(ccx, fn_ty); let sig = ccx.tcx().erase_late_bound_regions_and_normalize(&sig); let lldecl = match ccx.instances().borrow().get(&instance) { Some(&val) => val, None => bug!("Instance `{:?}` not already declared", instance) }; ccx.stats().borrow_mut().n_closures += 1; // The `uwtable` attribute according to LLVM is: // // This attribute indicates that the ABI being targeted requires that an // unwind table entry be produced for this function even if we can show // that no exceptions passes by it. This is normally the case for the // ELF x86-64 abi, but it can be disabled for some compilation units. // // Typically when we're compiling with `-C panic=abort` (which implies this // `no_landing_pads` check) we don't need `uwtable` because we can't // generate any exceptions! On Windows, however, exceptions include other // events such as illegal instructions, segfaults, etc. This means that on // Windows we end up still needing the `uwtable` attribute even if the `-C // panic=abort` flag is passed. // // You can also find more info on why Windows is whitelisted here in: // https://bugzilla.mozilla.org/show_bug.cgi?id=1302078 if !ccx.sess().no_landing_pads() || ccx.sess().target.target.options.is_like_windows { attributes::emit_uwtable(lldecl, true); } let mir = ccx.tcx().instance_mir(instance.def); mir::trans_mir(ccx, lldecl, &mir, instance, sig); } pub fn set_link_section(ccx: &CrateContext, llval: ValueRef, attrs: &[ast::Attribute]) { if let Some(sect) = attr::first_attr_value_str_by_name(attrs, "link_section") { if contains_null(§.as_str()) { ccx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", §)); } unsafe { let buf = CString::new(sect.as_str().as_bytes()).unwrap(); 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(ccx: &CrateContext) { let (main_def_id, span) = match *ccx.sess().entry_fn.borrow() { Some((id, span)) => { (ccx.tcx().hir.local_def_id(id), span) } None => return, }; let instance = Instance::mono(ccx.tcx(), main_def_id); if !ccx.codegen_unit().contains_item(&TransItem::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(ccx, instance); let et = ccx.sess().entry_type.get().unwrap(); match et { config::EntryMain => create_entry_fn(ccx, span, main_llfn, true), config::EntryStart => create_entry_fn(ccx, span, main_llfn, false), config::EntryNone => {} // Do nothing. } fn create_entry_fn(ccx: &CrateContext, sp: Span, rust_main: ValueRef, use_start_lang_item: bool) { // Signature of native main(), corresponding to C's `int main(int, char **)` let llfty = Type::func(&[Type::c_int(ccx), Type::i8p(ccx).ptr_to()], &Type::c_int(ccx)); if declare::get_defined_value(ccx, "main").is_some() { // FIXME: We should be smart and show a better diagnostic here. ccx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times") .help("did you use #[no_mangle] on `fn main`? Use #[start] instead") .emit(); ccx.sess().abort_if_errors(); bug!(); } let llfn = declare::declare_cfn(ccx, "main", llfty); // `main` should respect same config for frame pointer elimination as rest of code attributes::set_frame_pointer_elimination(ccx, llfn); let bld = Builder::new_block(ccx, llfn, "top"); debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx, &bld); // 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 = bld.intcast(param_argc, ccx.isize_ty(), true); let arg_argv = param_argv; let (start_fn, args) = if use_start_lang_item { let start_def_id = ccx.tcx().require_lang_item(StartFnLangItem); let start_instance = Instance::mono(ccx.tcx(), start_def_id); let start_fn = callee::get_fn(ccx, start_instance); (start_fn, vec![bld.pointercast(rust_main, Type::i8p(ccx).ptr_to()), arg_argc, arg_argv]) } else { debug!("using user-defined start fn"); (rust_main, vec![arg_argc, arg_argv]) }; let result = bld.call(start_fn, &args, None); // Return rust start function's result from native main() bld.ret(bld.intcast(result, Type::c_int(ccx), true)); } } fn contains_null(s: &str) -> bool { s.bytes().any(|b| b == 0) } fn write_metadata<'a, 'gcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, llmod_id: &str, link_meta: &LinkMeta, exported_symbols: &NodeSet) -> (ContextRef, ModuleRef, EncodedMetadata, EncodedMetadataHashes) { use std::io::Write; use flate2::Compression; use flate2::write::DeflateEncoder; let (metadata_llcx, metadata_llmod) = unsafe { context::create_context_and_module(tcx.sess, llmod_id) }; #[derive(PartialEq, Eq, PartialOrd, Ord)] enum MetadataKind { None, Uncompressed, Compressed } let kind = tcx.sess.crate_types.borrow().iter().map(|ty| { match *ty { config::CrateTypeExecutable | config::CrateTypeStaticlib | config::CrateTypeCdylib => MetadataKind::None, config::CrateTypeRlib => MetadataKind::Uncompressed, config::CrateTypeDylib | config::CrateTypeProcMacro => MetadataKind::Compressed, } }).max().unwrap(); if kind == MetadataKind::None { return (metadata_llcx, metadata_llmod, EncodedMetadata::new(), EncodedMetadataHashes::new()); } let (metadata, hashes) = tcx.encode_metadata(link_meta, exported_symbols); if kind == MetadataKind::Uncompressed { return (metadata_llcx, metadata_llmod, metadata, hashes); } 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 = symbol_export::metadata_symbol_name(tcx); let buf = CString::new(name).unwrap(); let llglobal = unsafe { llvm::LLVMAddGlobal(metadata_llmod, val_ty(llconst).to_ref(), buf.as_ptr()) }; unsafe { llvm::LLVMSetInitializer(llglobal, llconst); let section_name = metadata::metadata_section_name(&tcx.sess.target.target); let name = CString::new(section_name).unwrap(); 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_llcx, metadata_llmod, metadata, hashes); } pub struct ValueIter { cur: ValueRef, step: unsafe extern "C" fn(ValueRef) -> ValueRef, } impl Iterator for ValueIter { type Item = ValueRef; fn next(&mut self) -> Option { let old = self.cur; if !old.is_null() { self.cur = unsafe { (self.step)(old) }; Some(old) } else { None } } } pub fn iter_globals(llmod: llvm::ModuleRef) -> ValueIter { unsafe { ValueIter { cur: llvm::LLVMGetFirstGlobal(llmod), step: llvm::LLVMGetNextGlobal, } } } pub fn trans_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, rx: mpsc::Receiver>) -> OngoingCrateTranslation { check_for_rustc_errors_attr(tcx); if tcx.sess.opts.debugging_opts.thinlto { if unsafe { !llvm::LLVMRustThinLTOAvailable() } { tcx.sess.fatal("this compiler's LLVM does not support ThinLTO"); } } let crate_hash = tcx.dep_graph .fingerprint_of(&DepNode::new_no_params(DepKind::Krate)); let link_meta = link::build_link_meta(crate_hash); let exported_symbol_node_ids = find_exported_symbols(tcx); let shared_ccx = SharedCrateContext::new(tcx); // Translate the metadata. let llmod_id = "metadata"; let (metadata_llcx, metadata_llmod, metadata, metadata_incr_hashes) = time(tcx.sess.time_passes(), "write metadata", || { write_metadata(tcx, llmod_id, &link_meta, &exported_symbol_node_ids) }); let metadata_module = ModuleTranslation { name: link::METADATA_MODULE_NAME.to_string(), llmod_id: llmod_id.to_string(), source: ModuleSource::Translated(ModuleLlvm { llcx: metadata_llcx, llmod: metadata_llmod, tm: create_target_machine(tcx.sess), }), kind: ModuleKind::Metadata, }; let time_graph = if tcx.sess.opts.debugging_opts.trans_time_graph { Some(time_graph::TimeGraph::new()) } else { None }; // Skip crate items and just output metadata in -Z no-trans mode. if tcx.sess.opts.debugging_opts.no_trans || !tcx.sess.opts.output_types.should_trans() { let ongoing_translation = write::start_async_translation( tcx, time_graph.clone(), link_meta, metadata, rx, 1); ongoing_translation.submit_pre_translated_module_to_llvm(tcx, metadata_module); ongoing_translation.translation_finished(tcx); assert_and_save_dep_graph(tcx, metadata_incr_hashes, link_meta); ongoing_translation.check_for_errors(tcx.sess); return ongoing_translation; } // Run the translation item collector and partition the collected items into // codegen units. let codegen_units = shared_ccx.tcx().collect_and_partition_translation_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_translation = write::start_async_translation( tcx, time_graph.clone(), link_meta, metadata, rx, codegen_units.len()); // Translate an allocator shim, if any let allocator_module = if let Some(kind) = tcx.sess.allocator_kind.get() { unsafe { let llmod_id = "allocator"; let (llcx, llmod) = context::create_context_and_module(tcx.sess, llmod_id); let modules = ModuleLlvm { llmod, llcx, tm: create_target_machine(tcx.sess), }; time(tcx.sess.time_passes(), "write allocator module", || { allocator::trans(tcx, &modules, kind) }); Some(ModuleTranslation { name: link::ALLOCATOR_MODULE_NAME.to_string(), llmod_id: llmod_id.to_string(), source: ModuleSource::Translated(modules), kind: ModuleKind::Allocator, }) } } else { None }; if let Some(allocator_module) = allocator_module { ongoing_translation.submit_pre_translated_module_to_llvm(tcx, allocator_module); } ongoing_translation.submit_pre_translated_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. Note that "size" is defined rather crudely at the // moment as it is just the number of TransItems in the CGU, not taking into // account the size of each TransItem. let codegen_units = { let mut codegen_units = codegen_units; codegen_units.sort_by_key(|cgu| -(cgu.items().len() as isize)); codegen_units }; let mut total_trans_time = Duration::new(0, 0); let mut all_stats = Stats::default(); for cgu in codegen_units.into_iter() { ongoing_translation.wait_for_signal_to_translate_item(); ongoing_translation.check_for_errors(tcx.sess); // First, if incremental compilation is enabled, we try to re-use the // codegen unit from the cache. if tcx.dep_graph.is_fully_enabled() { let cgu_id = cgu.work_product_id(); // Check whether there is a previous work-product we can // re-use. Not only must the file exist, and the inputs not // be dirty, but the hash of the symbols we will generate must // be the same. if let Some(buf) = tcx.dep_graph.previous_work_product(&cgu_id) { let dep_node = &DepNode::new(tcx, DepConstructor::CompileCodegenUnit(cgu.name().clone())); // We try to mark the DepNode::CompileCodegenUnit green. If we // succeed it means that none of the dependencies has changed // and we can safely re-use. if let Some(dep_node_index) = tcx.dep_graph.try_mark_green(tcx, dep_node) { // Append ".rs" to LLVM module identifier. // // LLVM code generator emits a ".file filename" directive // for ELF backends. Value of the "filename" is set as the // LLVM module identifier. Due to a LLVM MC bug[1], LLVM // crashes if the module identifier is same as other symbols // such as a function name in the module. // 1. http://llvm.org/bugs/show_bug.cgi?id=11479 let llmod_id = format!("{}.rs", cgu.name()); let module = ModuleTranslation { name: cgu.name().to_string(), source: ModuleSource::Preexisting(buf), kind: ModuleKind::Regular, llmod_id, }; tcx.dep_graph.mark_loaded_from_cache(dep_node_index, true); write::submit_translated_module_to_llvm(tcx, module, 0); // Continue to next cgu, this one is done. continue } } else { // This can happen if files were deleted from the cache // directory for some reason. We just re-compile then. } } let _timing_guard = time_graph.as_ref().map(|time_graph| { time_graph.start(write::TRANS_WORKER_TIMELINE, write::TRANS_WORK_PACKAGE_KIND, &format!("codegen {}", cgu.name())) }); let start_time = Instant::now(); all_stats.extend(tcx.compile_codegen_unit(*cgu.name())); total_trans_time += start_time.elapsed(); ongoing_translation.check_for_errors(tcx.sess); } ongoing_translation.translation_finished(tcx); // Since the main thread is sometimes blocked during trans, we keep track // -Ztime-passes output manually. print_time_passes_entry(tcx.sess.time_passes(), "translate to LLVM IR", total_trans_time); if tcx.sess.opts.incremental.is_some() { assert_module_sources::assert_module_sources(tcx); } symbol_names_test::report_symbol_names(tcx); if shared_ccx.sess().trans_stats() { println!("--- trans 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 shared_ccx.sess().count_llvm_insns() { for (k, v) in all_stats.llvm_insns.iter() { println!("{:7} {}", *v, *k); } } ongoing_translation.check_for_errors(tcx.sess); assert_and_save_dep_graph(tcx, metadata_incr_hashes, link_meta); ongoing_translation } fn assert_and_save_dep_graph<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, metadata_incr_hashes: EncodedMetadataHashes, link_meta: LinkMeta) { time(tcx.sess.time_passes(), "assert dep graph", || rustc_incremental::assert_dep_graph(tcx)); time(tcx.sess.time_passes(), "serialize dep graph", || rustc_incremental::save_dep_graph(tcx, &metadata_incr_hashes, link_meta.crate_hash)); } #[inline(never)] // give this a place in the profiler fn assert_symbols_are_distinct<'a, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>, trans_items: I) where I: Iterator> { let mut symbols: Vec<_> = trans_items.map(|trans_item| { (trans_item, trans_item.symbol_name(tcx)) }).collect(); (&mut symbols[..]).sort_by(|&(_, ref sym1), &(_, ref sym2)|{ sym1.cmp(sym2) }); for pair in (&symbols[..]).windows(2) { let sym1 = &pair[0].1; let sym2 = &pair[1].1; if *sym1 == *sym2 { let trans_item1 = pair[0].0; let trans_item2 = pair[1].0; let span1 = trans_item1.local_span(tcx); let span2 = trans_item2.local_span(tcx); // Deterministically select one of the spans for error reporting let span = match (span1, span2) { (Some(span1), Some(span2)) => { Some(if span1.lo().0 > span2.lo().0 { span1 } else { span2 }) } (Some(span), None) | (None, Some(span)) => Some(span), _ => None }; let error_message = format!("symbol `{}` is already defined", sym1); if let Some(span) = span { tcx.sess.span_fatal(span, &error_message) } else { tcx.sess.fatal(&error_message) } } } } fn collect_and_partition_translation_items<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, cnum: CrateNum, ) -> (Arc, Arc>>>) { assert_eq!(cnum, LOCAL_CRATE); let time_passes = tcx.sess.time_passes(); let collection_mode = match tcx.sess.opts.debugging_opts.print_trans_items { Some(ref s) => { let mode_string = s.to_lowercase(); let mode_string = mode_string.trim(); if mode_string == "eager" { TransItemCollectionMode::Eager } else { if mode_string != "lazy" { let message = format!("Unknown codegen-item collection mode '{}'. \ Falling back to 'lazy' mode.", mode_string); tcx.sess.warn(&message); } TransItemCollectionMode::Lazy } } None => TransItemCollectionMode::Lazy }; let (items, inlining_map) = time(time_passes, "translation item collection", || { collector::collect_crate_translation_items(tcx, collection_mode) }); assert_symbols_are_distinct(tcx, items.iter()); let strategy = if tcx.sess.opts.debugging_opts.incremental.is_some() { PartitioningStrategy::PerModule } else { PartitioningStrategy::FixedUnitCount(tcx.sess.codegen_units()) }; let codegen_units = time(time_passes, "codegen unit partitioning", || { partitioning::partition(tcx, items.iter().cloned(), strategy, &inlining_map) .into_iter() .map(Arc::new) .collect::>() }); let translation_items: DefIdSet = items.iter().filter_map(|trans_item| { match *trans_item { TransItem::Fn(ref instance) => Some(instance.def_id()), _ => None, } }).collect(); if tcx.sess.opts.debugging_opts.print_trans_items.is_some() { let mut item_to_cgus = FxHashMap(); for cgu in &codegen_units { for (&trans_item, &linkage) in cgu.items() { item_to_cgus.entry(trans_item) .or_insert(Vec::new()) .push((cgu.name().clone(), linkage)); } } let mut item_keys: Vec<_> = items .iter() .map(|i| { let mut output = i.to_string(tcx); output.push_str(" @@"); let mut empty = Vec::new(); let cgus = item_to_cgus.get_mut(i).unwrap_or(&mut empty); cgus.as_mut_slice().sort_by_key(|&(ref name, _)| name.clone()); cgus.dedup(); for &(ref cgu_name, (linkage, _)) in cgus.iter() { output.push_str(" "); output.push_str(&cgu_name); let linkage_abbrev = match linkage { Linkage::External => "External", Linkage::AvailableExternally => "Available", Linkage::LinkOnceAny => "OnceAny", Linkage::LinkOnceODR => "OnceODR", Linkage::WeakAny => "WeakAny", Linkage::WeakODR => "WeakODR", Linkage::Appending => "Appending", Linkage::Internal => "Internal", Linkage::Private => "Private", Linkage::ExternalWeak => "ExternalWeak", Linkage::Common => "Common", }; output.push_str("["); output.push_str(linkage_abbrev); output.push_str("]"); } output }) .collect(); item_keys.sort(); for item in item_keys { println!("TRANS_ITEM {}", item); } } (Arc::new(translation_items), Arc::new(codegen_units)) } 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: FxHashSet(), native_libraries: FxHashMap(), used_libraries: tcx.native_libraries(LOCAL_CRATE), link_args: tcx.link_args(LOCAL_CRATE), crate_name: FxHashMap(), used_crates_dynamic: cstore::used_crates(tcx, LinkagePreference::RequireDynamic), used_crates_static: cstore::used_crates(tcx, LinkagePreference::RequireStatic), used_crate_source: FxHashMap(), }; for &cnum in tcx.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); } } return info } } fn is_translated_function(tcx: TyCtxt, id: DefId) -> bool { let (all_trans_items, _) = tcx.collect_and_partition_translation_items(LOCAL_CRATE); all_trans_items.contains(&id) } fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, cgu: InternedString) -> Stats { let cgu = tcx.codegen_unit(cgu); let start_time = Instant::now(); let (stats, module) = module_translation(tcx, cgu); let time_to_translate = start_time.elapsed(); // We assume that the cost to run LLVM on a CGU is proportional to // the time we needed for translating it. let cost = time_to_translate.as_secs() * 1_000_000_000 + time_to_translate.subsec_nanos() as u64; write::submit_translated_module_to_llvm(tcx, module, cost); return stats; fn module_translation<'a, 'tcx>( tcx: TyCtxt<'a, 'tcx, 'tcx>, cgu: Arc>) -> (Stats, ModuleTranslation) { let cgu_name = cgu.name().to_string(); // Append ".rs" to LLVM module identifier. // // LLVM code generator emits a ".file filename" directive // for ELF backends. Value of the "filename" is set as the // LLVM module identifier. Due to a LLVM MC bug[1], LLVM // crashes if the module identifier is same as other symbols // such as a function name in the module. // 1. http://llvm.org/bugs/show_bug.cgi?id=11479 let llmod_id = format!("{}-{}.rs", cgu.name(), tcx.crate_disambiguator(LOCAL_CRATE) .to_fingerprint().to_hex()); // Instantiate translation items without filling out definitions yet... let scx = SharedCrateContext::new(tcx); let lcx = LocalCrateContext::new(&scx, cgu, &llmod_id); let module = { let ccx = CrateContext::new(&scx, &lcx); let trans_items = ccx.codegen_unit() .items_in_deterministic_order(ccx.tcx()); for &(trans_item, (linkage, visibility)) in &trans_items { trans_item.predefine(&ccx, linkage, visibility); } // ... and now that we have everything pre-defined, fill out those definitions. for &(trans_item, _) in &trans_items { trans_item.define(&ccx); } // If this codegen unit contains the main function, also create the // wrapper here maybe_create_entry_wrapper(&ccx); // Run replace-all-uses-with for statics that need it for &(old_g, new_g) in ccx.statics_to_rauw().borrow().iter() { unsafe { let bitcast = llvm::LLVMConstPointerCast(new_g, llvm::LLVMTypeOf(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 !ccx.used_statics().borrow().is_empty() { let name = CString::new("llvm.used").unwrap(); let section = CString::new("llvm.metadata").unwrap(); let array = C_array(Type::i8(&ccx).ptr_to(), &*ccx.used_statics().borrow()); unsafe { let g = llvm::LLVMAddGlobal(ccx.llmod(), val_ty(array).to_ref(), name.as_ptr()); llvm::LLVMSetInitializer(g, array); llvm::LLVMRustSetLinkage(g, llvm::Linkage::AppendingLinkage); llvm::LLVMSetSection(g, section.as_ptr()); } } // Finalize debuginfo if ccx.sess().opts.debuginfo != NoDebugInfo { debuginfo::finalize(&ccx); } let llvm_module = ModuleLlvm { llcx: ccx.llcx(), llmod: ccx.llmod(), tm: create_target_machine(ccx.sess()), }; ModuleTranslation { name: cgu_name, source: ModuleSource::Translated(llvm_module), kind: ModuleKind::Regular, llmod_id, } }; (lcx.into_stats(), module) } } pub fn provide(providers: &mut Providers) { providers.collect_and_partition_translation_items = collect_and_partition_translation_items; providers.is_translated_function = is_translated_function; providers.codegen_unit = |tcx, name| { let (_, all) = tcx.collect_and_partition_translation_items(LOCAL_CRATE); all.iter() .find(|cgu| *cgu.name() == name) .cloned() .expect(&format!("failed to find cgu with name {:?}", name)) }; providers.compile_codegen_unit = compile_codegen_unit; } 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 ModuleTranslation; impl HashStable for ModuleTranslation { fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) { // do nothing } } }