1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10 //! Translate the completed AST to the LLVM IR.
12 //! Some functions here, such as trans_block and trans_expr, return a value --
13 //! the result of the translation to LLVM -- while others, such as trans_fn,
14 //! trans_impl, and trans_item, are called only for the side effect of adding a
15 //! particular definition to the LLVM IR output we're producing.
17 //! Hopefully useful general knowledge about trans:
19 //! * There's no way to find out the Ty type of a ValueRef. Doing so
20 //! would be "trying to get the eggs out of an omelette" (credit:
21 //! pcwalton). You can, instead, find out its TypeRef by calling val_ty,
22 //! but one TypeRef corresponds to many `Ty`s; for instance, tup(int, int,
23 //! int) and rec(x=int, y=int, z=int) will have the same TypeRef.
25 #![allow(non_camel_case_types)]
27 pub use self::ValueOrigin::*;
29 use super::CrateTranslation;
30 use super::ModuleTranslation;
32 use back::link::mangle_exported_name;
33 use back::{link, abi};
35 use llvm::{BasicBlockRef, Linkage, ValueRef, Vector, get_param};
38 use middle::cstore::CrateStore;
39 use middle::def_id::DefId;
41 use middle::lang_items::{LangItem, ExchangeMallocFnLangItem, StartFnLangItem};
42 use middle::weak_lang_items;
43 use middle::pat_util::simple_name;
44 use middle::subst::{self, Substs};
46 use middle::ty::{self, Ty, TypeFoldable};
47 use middle::ty::adjustment::CustomCoerceUnsized;
48 use rustc::dep_graph::DepNode;
49 use rustc::front::map as hir_map;
50 use rustc::util::common::time;
51 use rustc_mir::mir_map::MirMap;
52 use session::config::{self, NoDebugInfo, FullDebugInfo};
56 use trans::assert_dep_graph;
57 use trans::attributes;
59 use trans::builder::{Builder, noname};
61 use trans::cleanup::{self, CleanupMethods, DropHint};
63 use trans::common::{Block, C_bool, C_bytes_in_context, C_i32, C_int, C_uint, C_integral};
64 use trans::collector::{self, TransItem, TransItemState, TransItemCollectionMode};
65 use trans::common::{C_null, C_struct_in_context, C_u64, C_u8, C_undef};
66 use trans::common::{CrateContext, DropFlagHintsMap, Field, FunctionContext};
67 use trans::common::{Result, NodeIdAndSpan, VariantInfo};
68 use trans::common::{node_id_type, return_type_is_void, fulfill_obligation};
69 use trans::common::{type_is_immediate, type_is_zero_size, val_ty};
72 use trans::context::SharedCrateContext;
73 use trans::controlflow;
75 use trans::debuginfo::{self, DebugLoc, ToDebugLoc};
82 use trans::machine::{llsize_of, llsize_of_real};
85 use trans::monomorphize;
87 use trans::type_::Type;
89 use trans::type_of::*;
90 use trans::value::Value;
92 use util::common::indenter;
93 use util::sha2::Sha256;
94 use util::nodemap::{NodeMap, NodeSet};
96 use arena::TypedArena;
98 use std::ffi::{CStr, CString};
99 use std::cell::{Cell, RefCell};
100 use std::collections::{HashMap, HashSet};
102 use std::{i8, i16, i32, i64};
103 use syntax::abi::{Rust, RustCall, RustIntrinsic, PlatformIntrinsic, Abi};
104 use syntax::codemap::{Span, DUMMY_SP};
105 use syntax::parse::token::InternedString;
106 use syntax::attr::AttrMetaMethods;
109 use rustc_front::intravisit::{self, Visitor};
110 use rustc_front::hir;
114 static TASK_LOCAL_INSN_KEY: RefCell<Option<Vec<&'static str>>> = {
119 pub fn with_insn_ctxt<F>(blk: F)
120 where F: FnOnce(&[&'static str])
122 TASK_LOCAL_INSN_KEY.with(move |slot| {
123 slot.borrow().as_ref().map(move |s| blk(s));
127 pub fn init_insn_ctxt() {
128 TASK_LOCAL_INSN_KEY.with(|slot| {
129 *slot.borrow_mut() = Some(Vec::new());
133 pub struct _InsnCtxt {
134 _cannot_construct_outside_of_this_module: (),
137 impl Drop for _InsnCtxt {
139 TASK_LOCAL_INSN_KEY.with(|slot| {
140 match slot.borrow_mut().as_mut() {
150 pub fn push_ctxt(s: &'static str) -> _InsnCtxt {
151 debug!("new InsnCtxt: {}", s);
152 TASK_LOCAL_INSN_KEY.with(|slot| {
153 match slot.borrow_mut().as_mut() {
154 Some(ctx) => ctx.push(s),
159 _cannot_construct_outside_of_this_module: (),
163 pub struct StatRecorder<'a, 'tcx: 'a> {
164 ccx: &'a CrateContext<'a, 'tcx>,
165 name: Option<String>,
169 impl<'a, 'tcx> StatRecorder<'a, 'tcx> {
170 pub fn new(ccx: &'a CrateContext<'a, 'tcx>, name: String) -> StatRecorder<'a, 'tcx> {
171 let istart = ccx.stats().n_llvm_insns.get();
180 impl<'a, 'tcx> Drop for StatRecorder<'a, 'tcx> {
182 if self.ccx.sess().trans_stats() {
183 let iend = self.ccx.stats().n_llvm_insns.get();
188 .push((self.name.take().unwrap(), iend - self.istart));
189 self.ccx.stats().n_fns.set(self.ccx.stats().n_fns.get() + 1);
190 // Reset LLVM insn count to avoid compound costs.
191 self.ccx.stats().n_llvm_insns.set(self.istart);
196 fn get_extern_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
201 match ccx.externs().borrow().get(name) {
202 Some(n) => return *n,
206 let f = declare::declare_rust_fn(ccx, name, fn_ty);
208 let attrs = ccx.sess().cstore.item_attrs(did);
209 attributes::from_fn_attrs(ccx, &attrs[..], f);
211 ccx.externs().borrow_mut().insert(name.to_string(), f);
215 pub fn self_type_for_closure<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
219 let closure_kind = ccx.tcx().closure_kind(closure_id);
221 ty::FnClosureKind => {
222 ccx.tcx().mk_imm_ref(ccx.tcx().mk_region(ty::ReStatic), fn_ty)
224 ty::FnMutClosureKind => {
225 ccx.tcx().mk_mut_ref(ccx.tcx().mk_region(ty::ReStatic), fn_ty)
227 ty::FnOnceClosureKind => fn_ty,
231 pub fn kind_for_closure(ccx: &CrateContext, closure_id: DefId) -> ty::ClosureKind {
232 *ccx.tcx().tables.borrow().closure_kinds.get(&closure_id).unwrap()
235 pub fn get_extern_const<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
239 let name = ccx.sess().cstore.item_symbol(did);
240 let ty = type_of(ccx, t);
241 match ccx.externs().borrow_mut().get(&name) {
242 Some(n) => return *n,
245 // FIXME(nagisa): perhaps the map of externs could be offloaded to llvm somehow?
246 // FIXME(nagisa): investigate whether it can be changed into define_global
247 let c = declare::declare_global(ccx, &name[..], ty);
248 // Thread-local statics in some other crate need to *always* be linked
249 // against in a thread-local fashion, so we need to be sure to apply the
250 // thread-local attribute locally if it was present remotely. If we
251 // don't do this then linker errors can be generated where the linker
252 // complains that one object files has a thread local version of the
253 // symbol and another one doesn't.
254 for attr in ccx.tcx().get_attrs(did).iter() {
255 if attr.check_name("thread_local") {
256 llvm::set_thread_local(c, true);
259 if ccx.use_dll_storage_attrs() {
260 llvm::SetDLLStorageClass(c, llvm::DLLImportStorageClass);
262 ccx.externs().borrow_mut().insert(name.to_string(), c);
266 fn require_alloc_fn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, info_ty: Ty<'tcx>, it: LangItem) -> DefId {
267 match bcx.tcx().lang_items.require(it) {
270 bcx.sess().fatal(&format!("allocation of `{}` {}", info_ty, s));
275 // The following malloc_raw_dyn* functions allocate a box to contain
276 // a given type, but with a potentially dynamic size.
278 pub fn malloc_raw_dyn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
284 -> Result<'blk, 'tcx> {
285 let _icx = push_ctxt("malloc_raw_exchange");
288 let r = callee::trans_lang_call(bcx,
289 require_alloc_fn(bcx, info_ty, ExchangeMallocFnLangItem),
294 Result::new(r.bcx, PointerCast(r.bcx, r.val, llty_ptr))
298 pub fn bin_op_to_icmp_predicate(ccx: &CrateContext,
301 -> llvm::IntPredicate {
303 hir::BiEq => llvm::IntEQ,
304 hir::BiNe => llvm::IntNE,
305 hir::BiLt => if signed { llvm::IntSLT } else { llvm::IntULT },
306 hir::BiLe => if signed { llvm::IntSLE } else { llvm::IntULE },
307 hir::BiGt => if signed { llvm::IntSGT } else { llvm::IntUGT },
308 hir::BiGe => if signed { llvm::IntSGE } else { llvm::IntUGE },
311 .bug(&format!("comparison_op_to_icmp_predicate: expected comparison operator, \
318 pub fn bin_op_to_fcmp_predicate(ccx: &CrateContext, op: hir::BinOp_) -> llvm::RealPredicate {
320 hir::BiEq => llvm::RealOEQ,
321 hir::BiNe => llvm::RealUNE,
322 hir::BiLt => llvm::RealOLT,
323 hir::BiLe => llvm::RealOLE,
324 hir::BiGt => llvm::RealOGT,
325 hir::BiGe => llvm::RealOGE,
328 .bug(&format!("comparison_op_to_fcmp_predicate: expected comparison operator, \
335 pub fn compare_fat_ptrs<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
346 let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
347 let extra_eq = ICmp(bcx, llvm::IntEQ, lhs_extra, rhs_extra, debug_loc);
348 And(bcx, addr_eq, extra_eq, debug_loc)
351 let addr_eq = ICmp(bcx, llvm::IntNE, lhs_addr, rhs_addr, debug_loc);
352 let extra_eq = ICmp(bcx, llvm::IntNE, lhs_extra, rhs_extra, debug_loc);
353 Or(bcx, addr_eq, extra_eq, debug_loc)
355 hir::BiLe | hir::BiLt | hir::BiGe | hir::BiGt => {
356 // a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1)
357 let (op, strict_op) = match op {
358 hir::BiLt => (llvm::IntULT, llvm::IntULT),
359 hir::BiLe => (llvm::IntULE, llvm::IntULT),
360 hir::BiGt => (llvm::IntUGT, llvm::IntUGT),
361 hir::BiGe => (llvm::IntUGE, llvm::IntUGT),
365 let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
366 let extra_op = ICmp(bcx, op, lhs_extra, rhs_extra, debug_loc);
367 let addr_eq_extra_op = And(bcx, addr_eq, extra_op, debug_loc);
369 let addr_strict = ICmp(bcx, strict_op, lhs_addr, rhs_addr, debug_loc);
370 Or(bcx, addr_strict, addr_eq_extra_op, debug_loc)
373 bcx.tcx().sess.bug("unexpected fat ptr binop");
378 pub fn compare_scalar_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
386 ty::TyTuple(ref tys) if tys.is_empty() => {
387 // We don't need to do actual comparisons for nil.
388 // () == () holds but () < () does not.
390 hir::BiEq | hir::BiLe | hir::BiGe => return C_bool(bcx.ccx(), true),
391 hir::BiNe | hir::BiLt | hir::BiGt => return C_bool(bcx.ccx(), false),
392 // refinements would be nice
393 _ => bcx.sess().bug("compare_scalar_types: must be a comparison operator"),
396 ty::TyBareFn(..) | ty::TyBool | ty::TyUint(_) | ty::TyChar => {
398 bin_op_to_icmp_predicate(bcx.ccx(), op, false),
403 ty::TyRawPtr(mt) if common::type_is_sized(bcx.tcx(), mt.ty) => {
405 bin_op_to_icmp_predicate(bcx.ccx(), op, false),
411 let lhs_addr = Load(bcx, GEPi(bcx, lhs, &[0, abi::FAT_PTR_ADDR]));
412 let lhs_extra = Load(bcx, GEPi(bcx, lhs, &[0, abi::FAT_PTR_EXTRA]));
414 let rhs_addr = Load(bcx, GEPi(bcx, rhs, &[0, abi::FAT_PTR_ADDR]));
415 let rhs_extra = Load(bcx, GEPi(bcx, rhs, &[0, abi::FAT_PTR_EXTRA]));
416 compare_fat_ptrs(bcx,
427 bin_op_to_icmp_predicate(bcx.ccx(), op, true),
434 bin_op_to_fcmp_predicate(bcx.ccx(), op),
439 // Should never get here, because t is scalar.
440 _ => bcx.sess().bug("non-scalar type passed to compare_scalar_types"),
444 pub fn compare_simd_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
452 let signed = match t.sty {
454 let cmp = bin_op_to_fcmp_predicate(bcx.ccx(), op);
455 return SExt(bcx, FCmp(bcx, cmp, lhs, rhs, debug_loc), ret_ty);
457 ty::TyUint(_) => false,
458 ty::TyInt(_) => true,
459 _ => bcx.sess().bug("compare_simd_types: invalid SIMD type"),
462 let cmp = bin_op_to_icmp_predicate(bcx.ccx(), op, signed);
463 // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
464 // to get the correctly sized type. This will compile to a single instruction
465 // once the IR is converted to assembly if the SIMD instruction is supported
466 // by the target architecture.
467 SExt(bcx, ICmp(bcx, cmp, lhs, rhs, debug_loc), ret_ty)
470 // Iterates through the elements of a structural type.
471 pub fn iter_structural_ty<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>,
476 where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>
478 let _icx = push_ctxt("iter_structural_ty");
480 fn iter_variant<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>,
481 repr: &adt::Repr<'tcx>,
482 av: adt::MaybeSizedValue,
483 variant: ty::VariantDef<'tcx>,
484 substs: &Substs<'tcx>,
487 where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>
489 let _icx = push_ctxt("iter_variant");
493 for (i, field) in variant.fields.iter().enumerate() {
494 let arg = monomorphize::field_ty(tcx, substs, field);
496 adt::trans_field_ptr(cx, repr, av, Disr::from(variant.disr_val), i),
502 let value = if common::type_is_sized(cx.tcx(), t) {
503 adt::MaybeSizedValue::sized(av)
505 let data = Load(cx, expr::get_dataptr(cx, av));
506 let info = Load(cx, expr::get_meta(cx, av));
507 adt::MaybeSizedValue::unsized_(data, info)
512 ty::TyStruct(..) => {
513 let repr = adt::represent_type(cx.ccx(), t);
514 let VariantInfo { fields, discr } = VariantInfo::from_ty(cx.tcx(), t, None);
515 for (i, &Field(_, field_ty)) in fields.iter().enumerate() {
516 let llfld_a = adt::trans_field_ptr(cx, &*repr, value, Disr::from(discr), i);
518 let val = if common::type_is_sized(cx.tcx(), field_ty) {
521 let scratch = datum::rvalue_scratch_datum(cx, field_ty, "__fat_ptr_iter");
522 Store(cx, llfld_a, expr::get_dataptr(cx, scratch.val));
523 Store(cx, value.meta, expr::get_meta(cx, scratch.val));
526 cx = f(cx, val, field_ty);
529 ty::TyClosure(_, ref substs) => {
530 let repr = adt::represent_type(cx.ccx(), t);
531 for (i, upvar_ty) in substs.upvar_tys.iter().enumerate() {
532 let llupvar = adt::trans_field_ptr(cx, &*repr, value, Disr(0), i);
533 cx = f(cx, llupvar, upvar_ty);
536 ty::TyArray(_, n) => {
537 let (base, len) = tvec::get_fixed_base_and_len(cx, value.value, n);
538 let unit_ty = t.sequence_element_type(cx.tcx());
539 cx = tvec::iter_vec_raw(cx, base, unit_ty, len, f);
541 ty::TySlice(_) | ty::TyStr => {
542 let unit_ty = t.sequence_element_type(cx.tcx());
543 cx = tvec::iter_vec_raw(cx, value.value, unit_ty, value.meta, f);
545 ty::TyTuple(ref args) => {
546 let repr = adt::represent_type(cx.ccx(), t);
547 for (i, arg) in args.iter().enumerate() {
548 let llfld_a = adt::trans_field_ptr(cx, &*repr, value, Disr(0), i);
549 cx = f(cx, llfld_a, *arg);
552 ty::TyEnum(en, substs) => {
556 let repr = adt::represent_type(ccx, t);
557 let n_variants = en.variants.len();
559 // NB: we must hit the discriminant first so that structural
560 // comparison know not to proceed when the discriminants differ.
562 match adt::trans_switch(cx, &*repr, av) {
563 (_match::Single, None) => {
565 assert!(n_variants == 1);
566 cx = iter_variant(cx, &*repr, adt::MaybeSizedValue::sized(av),
567 &en.variants[0], substs, &mut f);
570 (_match::Switch, Some(lldiscrim_a)) => {
571 cx = f(cx, lldiscrim_a, cx.tcx().types.isize);
573 // Create a fall-through basic block for the "else" case of
574 // the switch instruction we're about to generate. Note that
575 // we do **not** use an Unreachable instruction here, even
576 // though most of the time this basic block will never be hit.
578 // When an enum is dropped it's contents are currently
579 // overwritten to DTOR_DONE, which means the discriminant
580 // could have changed value to something not within the actual
581 // range of the discriminant. Currently this function is only
582 // used for drop glue so in this case we just return quickly
583 // from the outer function, and any other use case will only
584 // call this for an already-valid enum in which case the `ret
585 // void` will never be hit.
586 let ret_void_cx = fcx.new_temp_block("enum-iter-ret-void");
587 RetVoid(ret_void_cx, DebugLoc::None);
588 let llswitch = Switch(cx, lldiscrim_a, ret_void_cx.llbb, n_variants);
589 let next_cx = fcx.new_temp_block("enum-iter-next");
591 for variant in &en.variants {
592 let variant_cx = fcx.new_temp_block(&format!("enum-iter-variant-{}",
595 let case_val = adt::trans_case(cx, &*repr, Disr::from(variant.disr_val));
596 AddCase(llswitch, case_val, variant_cx.llbb);
597 let variant_cx = iter_variant(variant_cx,
603 Br(variant_cx, next_cx.llbb, DebugLoc::None);
607 _ => ccx.sess().unimpl("value from adt::trans_switch in iter_structural_ty"),
611 cx.sess().unimpl(&format!("type in iter_structural_ty: {}", t))
618 /// Retrieve the information we are losing (making dynamic) in an unsizing
621 /// The `old_info` argument is a bit funny. It is intended for use
622 /// in an upcast, where the new vtable for an object will be drived
623 /// from the old one.
624 pub fn unsized_info<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>,
627 old_info: Option<ValueRef>,
628 param_substs: &'tcx Substs<'tcx>)
630 let (source, target) = ccx.tcx().struct_lockstep_tails(source, target);
631 match (&source.sty, &target.sty) {
632 (&ty::TyArray(_, len), &ty::TySlice(_)) => C_uint(ccx, len),
633 (&ty::TyTrait(_), &ty::TyTrait(_)) => {
634 // For now, upcasts are limited to changes in marker
635 // traits, and hence never actually require an actual
636 // change to the vtable.
637 old_info.expect("unsized_info: missing old info for trait upcast")
639 (_, &ty::TyTrait(box ty::TraitTy { ref principal, .. })) => {
640 // Note that we preserve binding levels here:
641 let substs = principal.0.substs.with_self_ty(source).erase_regions();
642 let substs = ccx.tcx().mk_substs(substs);
643 let trait_ref = ty::Binder(ty::TraitRef {
644 def_id: principal.def_id(),
647 consts::ptrcast(meth::get_vtable(ccx, trait_ref, param_substs),
648 Type::vtable_ptr(ccx))
650 _ => ccx.sess().bug(&format!("unsized_info: invalid unsizing {:?} -> {:?}",
656 /// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer.
657 pub fn unsize_thin_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
661 -> (ValueRef, ValueRef) {
662 debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
663 match (&src_ty.sty, &dst_ty.sty) {
664 (&ty::TyBox(a), &ty::TyBox(b)) |
665 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
666 &ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) |
667 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
668 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
669 (&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
670 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
671 assert!(common::type_is_sized(bcx.tcx(), a));
672 let ptr_ty = type_of::in_memory_type_of(bcx.ccx(), b).ptr_to();
673 (PointerCast(bcx, src, ptr_ty),
674 unsized_info(bcx.ccx(), a, b, None, bcx.fcx.param_substs))
676 _ => bcx.sess().bug("unsize_thin_ptr: called on bad types"),
680 /// Coerce `src`, which is a reference to a value of type `src_ty`,
681 /// to a value of type `dst_ty` and store the result in `dst`
682 pub fn coerce_unsized_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
687 match (&src_ty.sty, &dst_ty.sty) {
688 (&ty::TyBox(..), &ty::TyBox(..)) |
689 (&ty::TyRef(..), &ty::TyRef(..)) |
690 (&ty::TyRef(..), &ty::TyRawPtr(..)) |
691 (&ty::TyRawPtr(..), &ty::TyRawPtr(..)) => {
692 let (base, info) = if common::type_is_fat_ptr(bcx.tcx(), src_ty) {
693 // fat-ptr to fat-ptr unsize preserves the vtable
694 load_fat_ptr(bcx, src, src_ty)
696 let base = load_ty(bcx, src, src_ty);
697 unsize_thin_ptr(bcx, base, src_ty, dst_ty)
699 store_fat_ptr(bcx, base, info, dst, dst_ty);
702 // This can be extended to enums and tuples in the future.
703 // (&ty::TyEnum(def_id_a, _), &ty::TyEnum(def_id_b, _)) |
704 (&ty::TyStruct(def_a, _), &ty::TyStruct(def_b, _)) => {
705 assert_eq!(def_a, def_b);
707 let src_repr = adt::represent_type(bcx.ccx(), src_ty);
708 let src_fields = match &*src_repr {
709 &adt::Repr::Univariant(ref s, _) => &s.fields,
710 _ => bcx.sess().bug("struct has non-univariant repr"),
712 let dst_repr = adt::represent_type(bcx.ccx(), dst_ty);
713 let dst_fields = match &*dst_repr {
714 &adt::Repr::Univariant(ref s, _) => &s.fields,
715 _ => bcx.sess().bug("struct has non-univariant repr"),
718 let src = adt::MaybeSizedValue::sized(src);
719 let dst = adt::MaybeSizedValue::sized(dst);
721 let iter = src_fields.iter().zip(dst_fields).enumerate();
722 for (i, (src_fty, dst_fty)) in iter {
723 if type_is_zero_size(bcx.ccx(), dst_fty) {
727 let src_f = adt::trans_field_ptr(bcx, &src_repr, src, Disr(0), i);
728 let dst_f = adt::trans_field_ptr(bcx, &dst_repr, dst, Disr(0), i);
729 if src_fty == dst_fty {
730 memcpy_ty(bcx, dst_f, src_f, src_fty);
732 coerce_unsized_into(bcx, src_f, src_fty, dst_f, dst_fty);
736 _ => bcx.sess().bug(&format!("coerce_unsized_into: invalid coercion {:?} -> {:?}",
742 pub fn custom_coerce_unsize_info<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>,
745 -> CustomCoerceUnsized {
746 let trait_substs = Substs::erased(subst::VecPerParamSpace::new(vec![target_ty],
749 let trait_ref = ty::Binder(ty::TraitRef {
750 def_id: ccx.tcx().lang_items.coerce_unsized_trait().unwrap(),
751 substs: ccx.tcx().mk_substs(trait_substs)
754 match fulfill_obligation(ccx, DUMMY_SP, trait_ref) {
755 traits::VtableImpl(traits::VtableImplData { impl_def_id, .. }) => {
756 ccx.tcx().custom_coerce_unsized_kind(impl_def_id)
759 ccx.sess().bug(&format!("invalid CoerceUnsized vtable: {:?}",
765 pub fn cast_shift_expr_rhs(cx: Block, op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef {
766 cast_shift_rhs(op, lhs, rhs, |a, b| Trunc(cx, a, b), |a, b| ZExt(cx, a, b))
769 pub fn cast_shift_const_rhs(op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef {
773 |a, b| unsafe { llvm::LLVMConstTrunc(a, b.to_ref()) },
774 |a, b| unsafe { llvm::LLVMConstZExt(a, b.to_ref()) })
777 fn cast_shift_rhs<F, G>(op: hir::BinOp_,
783 where F: FnOnce(ValueRef, Type) -> ValueRef,
784 G: FnOnce(ValueRef, Type) -> ValueRef
786 // Shifts may have any size int on the rhs
787 if rustc_front::util::is_shift_binop(op) {
788 let mut rhs_llty = val_ty(rhs);
789 let mut lhs_llty = val_ty(lhs);
790 if rhs_llty.kind() == Vector {
791 rhs_llty = rhs_llty.element_type()
793 if lhs_llty.kind() == Vector {
794 lhs_llty = lhs_llty.element_type()
796 let rhs_sz = rhs_llty.int_width();
797 let lhs_sz = lhs_llty.int_width();
800 } else if lhs_sz > rhs_sz {
801 // FIXME (#1877: If shifting by negative
802 // values becomes not undefined then this is wrong.
812 pub fn llty_and_min_for_signed_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
817 let llty = Type::int_from_ty(cx.ccx(), t);
819 ast::TyIs if llty == Type::i32(cx.ccx()) => i32::MIN as u64,
820 ast::TyIs => i64::MIN as u64,
821 ast::TyI8 => i8::MIN as u64,
822 ast::TyI16 => i16::MIN as u64,
823 ast::TyI32 => i32::MIN as u64,
824 ast::TyI64 => i64::MIN as u64,
832 pub fn fail_if_zero_or_overflows<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
833 call_info: NodeIdAndSpan,
838 -> Block<'blk, 'tcx> {
839 let (zero_text, overflow_text) = if divrem.node == hir::BiDiv {
840 ("attempted to divide by zero",
841 "attempted to divide with overflow")
843 ("attempted remainder with a divisor of zero",
844 "attempted remainder with overflow")
846 let debug_loc = call_info.debug_loc();
848 let (is_zero, is_signed) = match rhs_t.sty {
850 let zero = C_integral(Type::int_from_ty(cx.ccx(), t), 0, false);
851 (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), true)
854 let zero = C_integral(Type::uint_from_ty(cx.ccx(), t), 0, false);
855 (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), false)
857 ty::TyStruct(def, _) if def.is_simd() => {
858 let mut res = C_bool(cx.ccx(), false);
859 for i in 0..rhs_t.simd_size(cx.tcx()) {
862 IsNull(cx, ExtractElement(cx, rhs, C_int(cx.ccx(), i as i64))),
868 cx.sess().bug(&format!("fail-if-zero on unexpected type: {}", rhs_t));
871 let bcx = with_cond(cx, is_zero, |bcx| {
872 controlflow::trans_fail(bcx, call_info, InternedString::new(zero_text))
875 // To quote LLVM's documentation for the sdiv instruction:
877 // Division by zero leads to undefined behavior. Overflow also leads
878 // to undefined behavior; this is a rare case, but can occur, for
879 // example, by doing a 32-bit division of -2147483648 by -1.
881 // In order to avoid undefined behavior, we perform runtime checks for
882 // signed division/remainder which would trigger overflow. For unsigned
883 // integers, no action beyond checking for zero need be taken.
885 let (llty, min) = llty_and_min_for_signed_ty(cx, rhs_t);
886 let minus_one = ICmp(bcx,
889 C_integral(llty, !0, false),
891 with_cond(bcx, minus_one, |bcx| {
892 let is_min = ICmp(bcx,
895 C_integral(llty, min, true),
897 with_cond(bcx, is_min, |bcx| {
898 controlflow::trans_fail(bcx, call_info, InternedString::new(overflow_text))
906 pub fn trans_external_path<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
910 let name = ccx.sess().cstore.item_symbol(did);
912 ty::TyBareFn(_, ref fn_ty) => {
913 match ccx.sess().target.target.adjust_abi(fn_ty.abi) {
915 get_extern_rust_fn(ccx, t, &name[..], did)
917 RustIntrinsic | PlatformIntrinsic => {
918 ccx.sess().bug("unexpected intrinsic in trans_external_path")
921 let attrs = ccx.sess().cstore.item_attrs(did);
922 foreign::register_foreign_item_fn(ccx, fn_ty.abi, t, &name, &attrs)
927 get_extern_const(ccx, did, t)
932 pub fn invoke<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
937 -> (ValueRef, Block<'blk, 'tcx>) {
938 let _icx = push_ctxt("invoke_");
939 if bcx.unreachable.get() {
940 return (C_null(Type::i8(bcx.ccx())), bcx);
943 let attributes = attributes::from_fn_type(bcx.ccx(), fn_ty);
945 match bcx.opt_node_id {
947 debug!("invoke at ???");
950 debug!("invoke at {}", bcx.tcx().map.node_to_string(id));
954 if need_invoke(bcx) {
955 debug!("invoking {} at {:?}", bcx.val_to_string(llfn), bcx.llbb);
956 for &llarg in llargs {
957 debug!("arg: {}", bcx.val_to_string(llarg));
959 let normal_bcx = bcx.fcx.new_temp_block("normal-return");
960 let landing_pad = bcx.fcx.get_landing_pad();
962 let llresult = Invoke(bcx,
969 return (llresult, normal_bcx);
971 debug!("calling {} at {:?}", bcx.val_to_string(llfn), bcx.llbb);
972 for &llarg in llargs {
973 debug!("arg: {}", bcx.val_to_string(llarg));
976 let llresult = Call(bcx, llfn, &llargs[..], Some(attributes), debug_loc);
977 return (llresult, bcx);
981 /// Returns whether this session's target will use SEH-based unwinding.
983 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
984 /// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
985 /// 64-bit MinGW) instead of "full SEH".
986 pub fn wants_msvc_seh(sess: &Session) -> bool {
987 sess.target.target.options.is_like_msvc && sess.target.target.arch == "x86"
990 pub fn avoid_invoke(bcx: Block) -> bool {
991 // FIXME(#25869) currently SEH-based unwinding is pretty buggy in LLVM and
992 // is being overhauled as this is being written. Until that
993 // time such that upstream LLVM's implementation is more solid
994 // and we start binding it we need to skip invokes for any
995 // target which wants SEH-based unwinding.
996 if bcx.sess().no_landing_pads() || wants_msvc_seh(bcx.sess()) {
998 } else if bcx.is_lpad {
999 // Avoid using invoke if we are already inside a landing pad.
1006 pub fn need_invoke(bcx: Block) -> bool {
1007 if avoid_invoke(bcx) {
1010 bcx.fcx.needs_invoke()
1014 pub fn load_if_immediate<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, t: Ty<'tcx>) -> ValueRef {
1015 let _icx = push_ctxt("load_if_immediate");
1016 if type_is_immediate(cx.ccx(), t) {
1017 return load_ty(cx, v, t);
1022 /// Helper for loading values from memory. Does the necessary conversion if the in-memory type
1023 /// differs from the type used for SSA values. Also handles various special cases where the type
1024 /// gives us better information about what we are loading.
1025 pub fn load_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ptr: ValueRef, t: Ty<'tcx>) -> ValueRef {
1026 if cx.unreachable.get() || type_is_zero_size(cx.ccx(), t) {
1027 return C_undef(type_of::type_of(cx.ccx(), t));
1030 let ptr = to_arg_ty_ptr(cx, ptr, t);
1031 let align = type_of::align_of(cx.ccx(), t);
1033 if type_is_immediate(cx.ccx(), t) && type_of::type_of(cx.ccx(), t).is_aggregate() {
1034 let load = Load(cx, ptr);
1036 llvm::LLVMSetAlignment(load, align);
1042 let global = llvm::LLVMIsAGlobalVariable(ptr);
1043 if !global.is_null() && llvm::LLVMIsGlobalConstant(global) == llvm::True {
1044 let val = llvm::LLVMGetInitializer(global);
1046 return to_arg_ty(cx, val, t);
1051 let val = if t.is_bool() {
1052 LoadRangeAssert(cx, ptr, 0, 2, llvm::False)
1053 } else if t.is_char() {
1054 // a char is a Unicode codepoint, and so takes values from 0
1055 // to 0x10FFFF inclusive only.
1056 LoadRangeAssert(cx, ptr, 0, 0x10FFFF + 1, llvm::False)
1057 } else if (t.is_region_ptr() || t.is_unique()) && !common::type_is_fat_ptr(cx.tcx(), t) {
1058 LoadNonNull(cx, ptr)
1064 llvm::LLVMSetAlignment(val, align);
1067 to_arg_ty(cx, val, t)
1070 /// Helper for storing values in memory. Does the necessary conversion if the in-memory type
1071 /// differs from the type used for SSA values.
1072 pub fn store_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, dst: ValueRef, t: Ty<'tcx>) {
1073 if cx.unreachable.get() {
1077 debug!("store_ty: {} : {:?} <- {}",
1078 cx.val_to_string(dst),
1080 cx.val_to_string(v));
1082 if common::type_is_fat_ptr(cx.tcx(), t) {
1084 ExtractValue(cx, v, abi::FAT_PTR_ADDR),
1085 expr::get_dataptr(cx, dst));
1087 ExtractValue(cx, v, abi::FAT_PTR_EXTRA),
1088 expr::get_meta(cx, dst));
1090 let store = Store(cx, from_arg_ty(cx, v, t), to_arg_ty_ptr(cx, dst, t));
1092 llvm::LLVMSetAlignment(store, type_of::align_of(cx.ccx(), t));
1097 pub fn store_fat_ptr<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
1102 // FIXME: emit metadata
1103 Store(cx, data, expr::get_dataptr(cx, dst));
1104 Store(cx, extra, expr::get_meta(cx, dst));
1107 pub fn load_fat_ptr<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
1110 -> (ValueRef, ValueRef) {
1111 // FIXME: emit metadata
1112 (Load(cx, expr::get_dataptr(cx, src)),
1113 Load(cx, expr::get_meta(cx, src)))
1116 pub fn from_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef {
1118 ZExt(bcx, val, Type::i8(bcx.ccx()))
1124 pub fn to_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef {
1126 Trunc(bcx, val, Type::i1(bcx.ccx()))
1132 pub fn to_arg_ty_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ptr: ValueRef, ty: Ty<'tcx>) -> ValueRef {
1133 if type_is_immediate(bcx.ccx(), ty) && type_of::type_of(bcx.ccx(), ty).is_aggregate() {
1134 // We want to pass small aggregates as immediate values, but using an aggregate LLVM type
1135 // for this leads to bad optimizations, so its arg type is an appropriately sized integer
1136 // and we have to convert it
1137 BitCast(bcx, ptr, type_of::arg_type_of(bcx.ccx(), ty).ptr_to())
1143 pub fn init_local<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, local: &hir::Local) -> Block<'blk, 'tcx> {
1144 debug!("init_local(bcx={}, local.id={})", bcx.to_str(), local.id);
1145 let _indenter = indenter();
1146 let _icx = push_ctxt("init_local");
1147 _match::store_local(bcx, local)
1150 pub fn raw_block<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>,
1152 llbb: BasicBlockRef)
1153 -> Block<'blk, 'tcx> {
1154 common::BlockS::new(llbb, is_lpad, None, fcx)
1157 pub fn with_cond<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>, val: ValueRef, f: F) -> Block<'blk, 'tcx>
1158 where F: FnOnce(Block<'blk, 'tcx>) -> Block<'blk, 'tcx>
1160 let _icx = push_ctxt("with_cond");
1162 if bcx.unreachable.get() || common::const_to_opt_uint(val) == Some(0) {
1167 let next_cx = fcx.new_temp_block("next");
1168 let cond_cx = fcx.new_temp_block("cond");
1169 CondBr(bcx, val, cond_cx.llbb, next_cx.llbb, DebugLoc::None);
1170 let after_cx = f(cond_cx);
1171 if !after_cx.terminated.get() {
1172 Br(after_cx, next_cx.llbb, DebugLoc::None);
1177 enum Lifetime { Start, End }
1179 // If LLVM lifetime intrinsic support is enabled (i.e. optimizations
1180 // on), and `ptr` is nonzero-sized, then extracts the size of `ptr`
1181 // and the intrinsic for `lt` and passes them to `emit`, which is in
1182 // charge of generating code to call the passed intrinsic on whatever
1183 // block of generated code is targetted for the intrinsic.
1185 // If LLVM lifetime intrinsic support is disabled (i.e. optimizations
1186 // off) or `ptr` is zero-sized, then no-op (does not call `emit`).
1187 fn core_lifetime_emit<'blk, 'tcx, F>(ccx: &'blk CrateContext<'blk, 'tcx>,
1191 where F: FnOnce(&'blk CrateContext<'blk, 'tcx>, machine::llsize, ValueRef)
1193 if ccx.sess().opts.optimize == config::OptLevel::No {
1197 let _icx = push_ctxt(match lt {
1198 Lifetime::Start => "lifetime_start",
1199 Lifetime::End => "lifetime_end"
1202 let size = machine::llsize_of_alloc(ccx, val_ty(ptr).element_type());
1207 let lifetime_intrinsic = ccx.get_intrinsic(match lt {
1208 Lifetime::Start => "llvm.lifetime.start",
1209 Lifetime::End => "llvm.lifetime.end"
1211 emit(ccx, size, lifetime_intrinsic)
1214 pub fn call_lifetime_start(cx: Block, ptr: ValueRef) {
1215 core_lifetime_emit(cx.ccx(), ptr, Lifetime::Start, |ccx, size, lifetime_start| {
1216 let ptr = PointerCast(cx, ptr, Type::i8p(ccx));
1219 &[C_u64(ccx, size), ptr],
1225 pub fn call_lifetime_end(cx: Block, ptr: ValueRef) {
1226 core_lifetime_emit(cx.ccx(), ptr, Lifetime::End, |ccx, size, lifetime_end| {
1227 let ptr = PointerCast(cx, ptr, Type::i8p(ccx));
1230 &[C_u64(ccx, size), ptr],
1236 // Generates code for resumption of unwind at the end of a landing pad.
1237 pub fn trans_unwind_resume(bcx: Block, lpval: ValueRef) {
1238 if !bcx.sess().target.target.options.custom_unwind_resume {
1241 let exc_ptr = ExtractValue(bcx, lpval, 0);
1242 let llunwresume = bcx.fcx.eh_unwind_resume();
1243 Call(bcx, llunwresume, &[exc_ptr], None, DebugLoc::None);
1249 pub fn call_memcpy(cx: Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) {
1250 let _icx = push_ctxt("call_memcpy");
1252 let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
1253 let key = format!("llvm.memcpy.p0i8.p0i8.i{}", ptr_width);
1254 let memcpy = ccx.get_intrinsic(&key);
1255 let src_ptr = PointerCast(cx, src, Type::i8p(ccx));
1256 let dst_ptr = PointerCast(cx, dst, Type::i8p(ccx));
1257 let size = IntCast(cx, n_bytes, ccx.int_type());
1258 let align = C_i32(ccx, align as i32);
1259 let volatile = C_bool(ccx, false);
1262 &[dst_ptr, src_ptr, size, align, volatile],
1267 pub fn memcpy_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, dst: ValueRef, src: ValueRef, t: Ty<'tcx>) {
1268 let _icx = push_ctxt("memcpy_ty");
1269 let ccx = bcx.ccx();
1271 if type_is_zero_size(ccx, t) {
1275 if t.is_structural() {
1276 let llty = type_of::type_of(ccx, t);
1277 let llsz = llsize_of(ccx, llty);
1278 let llalign = type_of::align_of(ccx, t);
1279 call_memcpy(bcx, dst, src, llsz, llalign as u32);
1280 } else if common::type_is_fat_ptr(bcx.tcx(), t) {
1281 let (data, extra) = load_fat_ptr(bcx, src, t);
1282 store_fat_ptr(bcx, data, extra, dst, t);
1284 store_ty(bcx, load_ty(bcx, src, t), dst, t);
1288 pub fn drop_done_fill_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) {
1289 if cx.unreachable.get() {
1292 let _icx = push_ctxt("drop_done_fill_mem");
1294 memfill(&B(bcx), llptr, t, adt::DTOR_DONE);
1297 pub fn init_zero_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) {
1298 if cx.unreachable.get() {
1301 let _icx = push_ctxt("init_zero_mem");
1303 memfill(&B(bcx), llptr, t, 0);
1306 // Always use this function instead of storing a constant byte to the memory
1307 // in question. e.g. if you store a zero constant, LLVM will drown in vreg
1308 // allocation for large data structures, and the generated code will be
1309 // awful. (A telltale sign of this is large quantities of
1310 // `mov [byte ptr foo],0` in the generated code.)
1311 fn memfill<'a, 'tcx>(b: &Builder<'a, 'tcx>, llptr: ValueRef, ty: Ty<'tcx>, byte: u8) {
1312 let _icx = push_ctxt("memfill");
1315 let llty = type_of::type_of(ccx, ty);
1316 let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
1317 let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width);
1319 let llintrinsicfn = ccx.get_intrinsic(&intrinsic_key);
1320 let llptr = b.pointercast(llptr, Type::i8(ccx).ptr_to());
1321 let llzeroval = C_u8(ccx, byte);
1322 let size = machine::llsize_of(ccx, llty);
1323 let align = C_i32(ccx, type_of::align_of(ccx, ty) as i32);
1324 let volatile = C_bool(ccx, false);
1325 b.call(llintrinsicfn,
1326 &[llptr, llzeroval, size, align, volatile],
1330 /// In general, when we create an scratch value in an alloca, the
1331 /// creator may not know if the block (that initializes the scratch
1332 /// with the desired value) actually dominates the cleanup associated
1333 /// with the scratch value.
1335 /// To deal with this, when we do an alloca (at the *start* of whole
1336 /// function body), we optionally can also set the associated
1337 /// dropped-flag state of the alloca to "dropped."
1338 #[derive(Copy, Clone, Debug)]
1339 pub enum InitAlloca {
1340 /// Indicates that the state should have its associated drop flag
1341 /// set to "dropped" at the point of allocation.
1343 /// Indicates the value of the associated drop flag is irrelevant.
1344 /// The embedded string literal is a programmer provided argument
1345 /// for why. This is a safeguard forcing compiler devs to
1346 /// document; it might be a good idea to also emit this as a
1347 /// comment with the alloca itself when emitting LLVM output.ll.
1348 Uninit(&'static str),
1352 pub fn alloc_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1354 name: &str) -> ValueRef {
1355 // pnkfelix: I do not know why alloc_ty meets the assumptions for
1356 // passing Uninit, but it was never needed (even back when we had
1357 // the original boolean `zero` flag on `lvalue_scratch_datum`).
1358 alloc_ty_init(bcx, t, InitAlloca::Uninit("all alloc_ty are uninit"), name)
1361 /// This variant of `fn alloc_ty` does not necessarily assume that the
1362 /// alloca should be created with no initial value. Instead the caller
1363 /// controls that assumption via the `init` flag.
1365 /// Note that if the alloca *is* initialized via `init`, then we will
1366 /// also inject an `llvm.lifetime.start` before that initialization
1367 /// occurs, and thus callers should not call_lifetime_start
1368 /// themselves. But if `init` says "uninitialized", then callers are
1369 /// in charge of choosing where to call_lifetime_start and
1370 /// subsequently populate the alloca.
1372 /// (See related discussion on PR #30823.)
1373 pub fn alloc_ty_init<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1376 name: &str) -> ValueRef {
1377 let _icx = push_ctxt("alloc_ty");
1378 let ccx = bcx.ccx();
1379 let ty = type_of::type_of(ccx, t);
1380 assert!(!t.has_param_types());
1382 InitAlloca::Dropped => alloca_dropped(bcx, t, name),
1383 InitAlloca::Uninit(_) => alloca(bcx, ty, name),
1387 pub fn alloca_dropped<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ty: Ty<'tcx>, name: &str) -> ValueRef {
1388 let _icx = push_ctxt("alloca_dropped");
1389 let llty = type_of::type_of(cx.ccx(), ty);
1390 if cx.unreachable.get() {
1391 unsafe { return llvm::LLVMGetUndef(llty.ptr_to().to_ref()); }
1393 let p = alloca(cx, llty, name);
1394 let b = cx.fcx.ccx.builder();
1395 b.position_before(cx.fcx.alloca_insert_pt.get().unwrap());
1397 // This is just like `call_lifetime_start` (but latter expects a
1398 // Block, which we do not have for `alloca_insert_pt`).
1399 core_lifetime_emit(cx.ccx(), p, Lifetime::Start, |ccx, size, lifetime_start| {
1400 let ptr = b.pointercast(p, Type::i8p(ccx));
1401 b.call(lifetime_start, &[C_u64(ccx, size), ptr], None);
1403 memfill(&b, p, ty, adt::DTOR_DONE);
1407 pub fn alloca(cx: Block, ty: Type, name: &str) -> ValueRef {
1408 let _icx = push_ctxt("alloca");
1409 if cx.unreachable.get() {
1411 return llvm::LLVMGetUndef(ty.ptr_to().to_ref());
1414 debuginfo::clear_source_location(cx.fcx);
1415 Alloca(cx, ty, name)
1418 pub fn set_value_name(val: ValueRef, name: &str) {
1420 let name = CString::new(name).unwrap();
1421 llvm::LLVMSetValueName(val, name.as_ptr());
1425 // Creates the alloca slot which holds the pointer to the slot for the final return value
1426 pub fn make_return_slot_pointer<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
1427 output_type: Ty<'tcx>)
1429 let lloutputtype = type_of::type_of(fcx.ccx, output_type);
1431 // We create an alloca to hold a pointer of type `output_type`
1432 // which will hold the pointer to the right alloca which has the
1434 if fcx.needs_ret_allocas {
1435 // Let's create the stack slot
1436 let slot = AllocaFcx(fcx, lloutputtype.ptr_to(), "llretslotptr");
1438 // and if we're using an out pointer, then store that in our newly made slot
1439 if type_of::return_uses_outptr(fcx.ccx, output_type) {
1440 let outptr = get_param(fcx.llfn, 0);
1442 let b = fcx.ccx.builder();
1443 b.position_before(fcx.alloca_insert_pt.get().unwrap());
1444 b.store(outptr, slot);
1449 // But if there are no nested returns, we skip the indirection and have a single
1452 if type_of::return_uses_outptr(fcx.ccx, output_type) {
1453 get_param(fcx.llfn, 0)
1455 AllocaFcx(fcx, lloutputtype, "sret_slot")
1460 struct FindNestedReturn {
1464 impl FindNestedReturn {
1465 fn new() -> FindNestedReturn {
1472 impl<'v> Visitor<'v> for FindNestedReturn {
1473 fn visit_expr(&mut self, e: &hir::Expr) {
1475 hir::ExprRet(..) => {
1478 _ => intravisit::walk_expr(self, e),
1483 fn build_cfg(tcx: &ty::ctxt, id: ast::NodeId) -> (ast::NodeId, Option<cfg::CFG>) {
1484 let blk = match tcx.map.find(id) {
1485 Some(hir_map::NodeItem(i)) => {
1487 hir::ItemFn(_, _, _, _, _, ref blk) => {
1490 _ => tcx.sess.bug("unexpected item variant in has_nested_returns"),
1493 Some(hir_map::NodeTraitItem(trait_item)) => {
1494 match trait_item.node {
1495 hir::MethodTraitItem(_, Some(ref body)) => body,
1497 tcx.sess.bug("unexpected variant: trait item other than a provided method in \
1498 has_nested_returns")
1502 Some(hir_map::NodeImplItem(impl_item)) => {
1503 match impl_item.node {
1504 hir::ImplItemKind::Method(_, ref body) => body,
1506 tcx.sess.bug("unexpected variant: non-method impl item in has_nested_returns")
1510 Some(hir_map::NodeExpr(e)) => {
1512 hir::ExprClosure(_, _, ref blk) => blk,
1513 _ => tcx.sess.bug("unexpected expr variant in has_nested_returns"),
1516 Some(hir_map::NodeVariant(..)) |
1517 Some(hir_map::NodeStructCtor(..)) => return (ast::DUMMY_NODE_ID, None),
1520 None if id == ast::DUMMY_NODE_ID => return (ast::DUMMY_NODE_ID, None),
1522 _ => tcx.sess.bug(&format!("unexpected variant in has_nested_returns: {}",
1523 tcx.map.path_to_string(id))),
1526 (blk.id, Some(cfg::CFG::new(tcx, blk)))
1529 // Checks for the presence of "nested returns" in a function.
1530 // Nested returns are when the inner expression of a return expression
1531 // (the 'expr' in 'return expr') contains a return expression. Only cases
1532 // where the outer return is actually reachable are considered. Implicit
1533 // returns from the end of blocks are considered as well.
1535 // This check is needed to handle the case where the inner expression is
1536 // part of a larger expression that may have already partially-filled the
1537 // return slot alloca. This can cause errors related to clean-up due to
1538 // the clobbering of the existing value in the return slot.
1539 fn has_nested_returns(tcx: &ty::ctxt, cfg: &cfg::CFG, blk_id: ast::NodeId) -> bool {
1540 for index in cfg.graph.depth_traverse(cfg.entry) {
1541 let n = cfg.graph.node_data(index);
1542 match tcx.map.find(n.id()) {
1543 Some(hir_map::NodeExpr(ex)) => {
1544 if let hir::ExprRet(Some(ref ret_expr)) = ex.node {
1545 let mut visitor = FindNestedReturn::new();
1546 intravisit::walk_expr(&mut visitor, &**ret_expr);
1552 Some(hir_map::NodeBlock(blk)) if blk.id == blk_id => {
1553 let mut visitor = FindNestedReturn::new();
1554 walk_list!(&mut visitor, visit_expr, &blk.expr);
1566 // NB: must keep 4 fns in sync:
1569 // - create_datums_for_fn_args.
1573 // Be warned! You must call `init_function` before doing anything with the
1574 // returned function context.
1575 pub fn new_fn_ctxt<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>,
1579 output_type: ty::FnOutput<'tcx>,
1580 param_substs: &'tcx Substs<'tcx>,
1582 block_arena: &'a TypedArena<common::BlockS<'a, 'tcx>>)
1583 -> FunctionContext<'a, 'tcx> {
1584 common::validate_substs(param_substs);
1586 debug!("new_fn_ctxt(path={}, id={}, param_substs={:?})",
1590 ccx.tcx().map.path_to_string(id).to_string()
1595 let uses_outptr = match output_type {
1596 ty::FnConverging(output_type) => {
1597 let substd_output_type = monomorphize::apply_param_substs(ccx.tcx(),
1600 type_of::return_uses_outptr(ccx, substd_output_type)
1602 ty::FnDiverging => false,
1604 let debug_context = debuginfo::create_function_debug_context(ccx, id, param_substs, llfndecl);
1605 let (blk_id, cfg) = build_cfg(ccx.tcx(), id);
1606 let nested_returns = if let Some(ref cfg) = cfg {
1607 has_nested_returns(ccx.tcx(), cfg, blk_id)
1612 let mir = ccx.mir_map().get(&id);
1614 let mut fcx = FunctionContext {
1618 llretslotptr: Cell::new(None),
1619 param_env: ccx.tcx().empty_parameter_environment(),
1620 alloca_insert_pt: Cell::new(None),
1621 llreturn: Cell::new(None),
1622 needs_ret_allocas: nested_returns,
1623 personality: Cell::new(None),
1624 caller_expects_out_pointer: uses_outptr,
1625 lllocals: RefCell::new(NodeMap()),
1626 llupvars: RefCell::new(NodeMap()),
1627 lldropflag_hints: RefCell::new(DropFlagHintsMap::new()),
1629 param_substs: param_substs,
1631 block_arena: block_arena,
1633 debug_context: debug_context,
1634 scopes: RefCell::new(Vec::new()),
1639 fcx.llenv = Some(get_param(fcx.llfn, fcx.env_arg_pos() as c_uint))
1645 /// Performs setup on a newly created function, creating the entry scope block
1646 /// and allocating space for the return pointer.
1647 pub fn init_function<'a, 'tcx>(fcx: &'a FunctionContext<'a, 'tcx>,
1649 output: ty::FnOutput<'tcx>)
1650 -> Block<'a, 'tcx> {
1651 let entry_bcx = fcx.new_temp_block("entry-block");
1653 // Use a dummy instruction as the insertion point for all allocas.
1654 // This is later removed in FunctionContext::cleanup.
1655 fcx.alloca_insert_pt.set(Some(unsafe {
1656 Load(entry_bcx, C_null(Type::i8p(fcx.ccx)));
1657 llvm::LLVMGetFirstInstruction(entry_bcx.llbb)
1660 if let ty::FnConverging(output_type) = output {
1661 // This shouldn't need to recompute the return type,
1662 // as new_fn_ctxt did it already.
1663 let substd_output_type = fcx.monomorphize(&output_type);
1664 if !return_type_is_void(fcx.ccx, substd_output_type) {
1665 // If the function returns nil/bot, there is no real return
1666 // value, so do not set `llretslotptr`.
1667 if !skip_retptr || fcx.caller_expects_out_pointer {
1668 // Otherwise, we normally allocate the llretslotptr, unless we
1669 // have been instructed to skip it for immediate return
1671 fcx.llretslotptr.set(Some(make_return_slot_pointer(fcx, substd_output_type)));
1676 // Create the drop-flag hints for every unfragmented path in the function.
1677 let tcx = fcx.ccx.tcx();
1678 let fn_did = tcx.map.local_def_id(fcx.id);
1679 let tables = tcx.tables.borrow();
1680 let mut hints = fcx.lldropflag_hints.borrow_mut();
1681 let fragment_infos = tcx.fragment_infos.borrow();
1683 // Intern table for drop-flag hint datums.
1684 let mut seen = HashMap::new();
1686 if let Some(fragment_infos) = fragment_infos.get(&fn_did) {
1687 for &info in fragment_infos {
1689 let make_datum = |id| {
1690 let init_val = C_u8(fcx.ccx, adt::DTOR_NEEDED_HINT);
1691 let llname = &format!("dropflag_hint_{}", id);
1692 debug!("adding hint {}", llname);
1693 let ty = tcx.types.u8;
1694 let ptr = alloc_ty(entry_bcx, ty, llname);
1695 Store(entry_bcx, init_val, ptr);
1696 let flag = datum::Lvalue::new_dropflag_hint("base::init_function");
1697 datum::Datum::new(ptr, ty, flag)
1700 let (var, datum) = match info {
1701 ty::FragmentInfo::Moved { var, .. } |
1702 ty::FragmentInfo::Assigned { var, .. } => {
1703 let opt_datum = seen.get(&var).cloned().unwrap_or_else(|| {
1704 let ty = tables.node_types[&var];
1705 if fcx.type_needs_drop(ty) {
1706 let datum = make_datum(var);
1707 seen.insert(var, Some(datum.clone()));
1710 // No drop call needed, so we don't need a dropflag hint
1714 if let Some(datum) = opt_datum {
1722 ty::FragmentInfo::Moved { move_expr: expr_id, .. } => {
1723 debug!("FragmentInfo::Moved insert drop hint for {}", expr_id);
1724 hints.insert(expr_id, DropHint::new(var, datum));
1726 ty::FragmentInfo::Assigned { assignee_id: expr_id, .. } => {
1727 debug!("FragmentInfo::Assigned insert drop hint for {}", expr_id);
1728 hints.insert(expr_id, DropHint::new(var, datum));
1737 // NB: must keep 4 fns in sync:
1740 // - create_datums_for_fn_args.
1744 pub fn arg_kind<'a, 'tcx>(cx: &FunctionContext<'a, 'tcx>, t: Ty<'tcx>) -> datum::Rvalue {
1745 use trans::datum::{ByRef, ByValue};
1748 mode: if arg_is_indirect(cx.ccx, t) { ByRef } else { ByValue }
1752 // create_datums_for_fn_args: creates lvalue datums for each of the
1753 // incoming function arguments.
1754 pub fn create_datums_for_fn_args<'a, 'tcx>(mut bcx: Block<'a, 'tcx>,
1756 arg_tys: &[Ty<'tcx>],
1757 has_tupled_arg: bool,
1758 arg_scope: cleanup::CustomScopeIndex)
1759 -> Block<'a, 'tcx> {
1760 let _icx = push_ctxt("create_datums_for_fn_args");
1762 let arg_scope_id = cleanup::CustomScope(arg_scope);
1764 debug!("create_datums_for_fn_args");
1766 // Return an array wrapping the ValueRefs that we get from `get_param` for
1767 // each argument into datums.
1769 // For certain mode/type combinations, the raw llarg values are passed
1770 // by value. However, within the fn body itself, we want to always
1771 // have all locals and arguments be by-ref so that we can cancel the
1772 // cleanup and for better interaction with LLVM's debug info. So, if
1773 // the argument would be passed by value, we store it into an alloca.
1774 // This alloca should be optimized away by LLVM's mem-to-reg pass in
1775 // the event it's not truly needed.
1776 let mut idx = fcx.arg_offset() as c_uint;
1777 let uninit_reason = InitAlloca::Uninit("fn_arg populate dominates dtor");
1778 for (i, &arg_ty) in arg_tys.iter().enumerate() {
1779 let arg_datum = if !has_tupled_arg || i < arg_tys.len() - 1 {
1780 if type_of::arg_is_indirect(bcx.ccx(), arg_ty) &&
1781 bcx.sess().opts.debuginfo != FullDebugInfo {
1782 // Don't copy an indirect argument to an alloca, the caller
1783 // already put it in a temporary alloca and gave it up, unless
1784 // we emit extra-debug-info, which requires local allocas :(.
1785 let llarg = get_param(fcx.llfn, idx);
1787 bcx.fcx.schedule_lifetime_end(arg_scope_id, llarg);
1788 bcx.fcx.schedule_drop_mem(arg_scope_id, llarg, arg_ty, None);
1790 datum::Datum::new(llarg,
1792 datum::Lvalue::new("create_datum_for_fn_args"))
1793 } else if common::type_is_fat_ptr(bcx.tcx(), arg_ty) {
1794 let data = get_param(fcx.llfn, idx);
1795 let extra = get_param(fcx.llfn, idx + 1);
1797 unpack_datum!(bcx, datum::lvalue_scratch_datum(bcx, arg_ty, "", uninit_reason,
1798 arg_scope_id, (data, extra),
1799 |(data, extra), bcx, dst| {
1800 debug!("populate call for create_datum_for_fn_args \
1801 early fat arg, on arg[{}] ty={:?}", i, arg_ty);
1803 Store(bcx, data, expr::get_dataptr(bcx, dst));
1804 Store(bcx, extra, expr::get_meta(bcx, dst));
1808 let llarg = get_param(fcx.llfn, idx);
1810 let tmp = datum::Datum::new(llarg, arg_ty, arg_kind(fcx, arg_ty));
1812 datum::lvalue_scratch_datum(bcx,
1820 debug!("populate call for create_datum_for_fn_args \
1821 early thin arg, on arg[{}] ty={:?}", i, arg_ty);
1823 tmp.store_to(bcx, dst)
1827 // FIXME(pcwalton): Reduce the amount of code bloat this is responsible for.
1829 ty::TyTuple(ref tupled_arg_tys) => {
1831 datum::lvalue_scratch_datum(bcx,
1840 debug!("populate call for create_datum_for_fn_args \
1841 tupled_args, on arg[{}] ty={:?}", i, arg_ty);
1842 for (j, &tupled_arg_ty) in
1843 tupled_arg_tys.iter().enumerate() {
1844 let lldest = StructGEP(bcx, llval, j);
1845 if common::type_is_fat_ptr(bcx.tcx(), tupled_arg_ty) {
1846 let data = get_param(bcx.fcx.llfn, idx);
1847 let extra = get_param(bcx.fcx.llfn, idx + 1);
1848 Store(bcx, data, expr::get_dataptr(bcx, lldest));
1849 Store(bcx, extra, expr::get_meta(bcx, lldest));
1852 let datum = datum::Datum::new(
1853 get_param(bcx.fcx.llfn, idx),
1855 arg_kind(bcx.fcx, tupled_arg_ty));
1857 bcx = datum.store_to(bcx, lldest);
1866 .bug("last argument of a function with `rust-call` ABI isn't a tuple?!")
1871 let pat = &*args[i].pat;
1872 bcx = if let Some(name) = simple_name(pat) {
1873 // Generate nicer LLVM for the common case of fn a pattern
1875 set_value_name(arg_datum.val, &bcx.name(name));
1876 bcx.fcx.lllocals.borrow_mut().insert(pat.id, arg_datum);
1879 // General path. Copy out the values that are used in the
1881 _match::bind_irrefutable_pat(bcx, pat, arg_datum.match_input(), arg_scope_id)
1883 debuginfo::create_argument_metadata(bcx, &args[i]);
1889 // Ties up the llstaticallocas -> llloadenv -> lltop edges,
1890 // and builds the return block.
1891 pub fn finish_fn<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>,
1892 last_bcx: Block<'blk, 'tcx>,
1893 retty: ty::FnOutput<'tcx>,
1894 ret_debug_loc: DebugLoc) {
1895 let _icx = push_ctxt("finish_fn");
1897 let ret_cx = match fcx.llreturn.get() {
1899 if !last_bcx.terminated.get() {
1900 Br(last_bcx, llreturn, DebugLoc::None);
1902 raw_block(fcx, false, llreturn)
1907 // This shouldn't need to recompute the return type,
1908 // as new_fn_ctxt did it already.
1909 let substd_retty = fcx.monomorphize(&retty);
1910 build_return_block(fcx, ret_cx, substd_retty, ret_debug_loc);
1912 debuginfo::clear_source_location(fcx);
1916 // Builds the return block for a function.
1917 pub fn build_return_block<'blk, 'tcx>(fcx: &FunctionContext<'blk, 'tcx>,
1918 ret_cx: Block<'blk, 'tcx>,
1919 retty: ty::FnOutput<'tcx>,
1920 ret_debug_location: DebugLoc) {
1921 if fcx.llretslotptr.get().is_none() ||
1922 (!fcx.needs_ret_allocas && fcx.caller_expects_out_pointer) {
1923 return RetVoid(ret_cx, ret_debug_location);
1926 let retslot = if fcx.needs_ret_allocas {
1927 Load(ret_cx, fcx.llretslotptr.get().unwrap())
1929 fcx.llretslotptr.get().unwrap()
1931 let retptr = Value(retslot);
1932 match retptr.get_dominating_store(ret_cx) {
1933 // If there's only a single store to the ret slot, we can directly return
1934 // the value that was stored and omit the store and the alloca
1936 let retval = s.get_operand(0).unwrap().get();
1937 s.erase_from_parent();
1939 if retptr.has_no_uses() {
1940 retptr.erase_from_parent();
1943 let retval = if retty == ty::FnConverging(fcx.ccx.tcx().types.bool) {
1944 Trunc(ret_cx, retval, Type::i1(fcx.ccx))
1949 if fcx.caller_expects_out_pointer {
1950 if let ty::FnConverging(retty) = retty {
1951 store_ty(ret_cx, retval, get_param(fcx.llfn, 0), retty);
1953 RetVoid(ret_cx, ret_debug_location)
1955 Ret(ret_cx, retval, ret_debug_location)
1958 // Otherwise, copy the return value to the ret slot
1959 None => match retty {
1960 ty::FnConverging(retty) => {
1961 if fcx.caller_expects_out_pointer {
1962 memcpy_ty(ret_cx, get_param(fcx.llfn, 0), retslot, retty);
1963 RetVoid(ret_cx, ret_debug_location)
1965 Ret(ret_cx, load_ty(ret_cx, retslot, retty), ret_debug_location)
1968 ty::FnDiverging => {
1969 if fcx.caller_expects_out_pointer {
1970 RetVoid(ret_cx, ret_debug_location)
1972 Ret(ret_cx, C_undef(Type::nil(fcx.ccx)), ret_debug_location)
1979 /// Builds an LLVM function out of a source function.
1981 /// If the function closes over its environment a closure will be returned.
1982 pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1986 param_substs: &'tcx Substs<'tcx>,
1987 fn_ast_id: ast::NodeId,
1988 attributes: &[ast::Attribute],
1989 output_type: ty::FnOutput<'tcx>,
1991 closure_env: closure::ClosureEnv<'b>) {
1992 ccx.stats().n_closures.set(ccx.stats().n_closures.get() + 1);
1994 record_translation_item_as_generated(ccx, fn_ast_id, param_substs);
1996 let _icx = push_ctxt("trans_closure");
1997 attributes::emit_uwtable(llfndecl, true);
1999 debug!("trans_closure(..., param_substs={:?})", param_substs);
2001 let has_env = match closure_env {
2002 closure::ClosureEnv::Closure(..) => true,
2003 closure::ClosureEnv::NotClosure => false,
2006 let (arena, fcx): (TypedArena<_>, FunctionContext);
2007 arena = TypedArena::new();
2008 fcx = new_fn_ctxt(ccx,
2016 let mut bcx = init_function(&fcx, false, output_type);
2018 if attributes.iter().any(|item| item.check_name("rustc_mir")) {
2019 mir::trans_mir(bcx);
2024 // cleanup scope for the incoming arguments
2025 let fn_cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(ccx,
2029 let arg_scope = fcx.push_custom_cleanup_scope_with_debug_loc(fn_cleanup_debug_loc);
2031 let block_ty = node_id_type(bcx, body.id);
2033 // Set up arguments to the function.
2034 let monomorphized_arg_types = decl.inputs
2036 .map(|arg| node_id_type(bcx, arg.id))
2037 .collect::<Vec<_>>();
2038 for monomorphized_arg_type in &monomorphized_arg_types {
2039 debug!("trans_closure: monomorphized_arg_type: {:?}",
2040 monomorphized_arg_type);
2042 debug!("trans_closure: function lltype: {}",
2043 bcx.fcx.ccx.tn().val_to_string(bcx.fcx.llfn));
2045 let has_tupled_arg = match closure_env {
2046 closure::ClosureEnv::NotClosure => abi == RustCall,
2050 bcx = create_datums_for_fn_args(bcx,
2052 &monomorphized_arg_types,
2056 bcx = closure_env.load(bcx, cleanup::CustomScope(arg_scope));
2058 // Up until here, IR instructions for this function have explicitly not been annotated with
2059 // source code location, so we don't step into call setup code. From here on, source location
2060 // emitting should be enabled.
2061 debuginfo::start_emitting_source_locations(&fcx);
2063 let dest = match fcx.llretslotptr.get() {
2064 Some(_) => expr::SaveIn(fcx.get_ret_slot(bcx, ty::FnConverging(block_ty), "iret_slot")),
2066 assert!(type_is_zero_size(bcx.ccx(), block_ty));
2071 // This call to trans_block is the place where we bridge between
2072 // translation calls that don't have a return value (trans_crate,
2073 // trans_mod, trans_item, et cetera) and those that do
2074 // (trans_block, trans_expr, et cetera).
2075 bcx = controlflow::trans_block(bcx, body, dest);
2078 expr::SaveIn(slot) if fcx.needs_ret_allocas => {
2079 Store(bcx, slot, fcx.llretslotptr.get().unwrap());
2084 match fcx.llreturn.get() {
2086 Br(bcx, fcx.return_exit_block(), DebugLoc::None);
2087 fcx.pop_custom_cleanup_scope(arg_scope);
2090 // Microoptimization writ large: avoid creating a separate
2091 // llreturn basic block
2092 bcx = fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_scope);
2096 // Put return block after all other blocks.
2097 // This somewhat improves single-stepping experience in debugger.
2099 let llreturn = fcx.llreturn.get();
2100 if let Some(llreturn) = llreturn {
2101 llvm::LLVMMoveBasicBlockAfter(llreturn, bcx.llbb);
2105 let ret_debug_loc = DebugLoc::At(fn_cleanup_debug_loc.id, fn_cleanup_debug_loc.span);
2107 // Insert the mandatory first few basic blocks before lltop.
2108 finish_fn(&fcx, bcx, output_type, ret_debug_loc);
2110 fn record_translation_item_as_generated<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2111 node_id: ast::NodeId,
2112 param_substs: &'tcx Substs<'tcx>) {
2113 if !collector::collecting_debug_information(ccx) {
2117 let def_id = match ccx.tcx().node_id_to_type(node_id).sty {
2118 ty::TyClosure(def_id, _) => def_id,
2119 _ => ccx.external_srcs()
2123 .unwrap_or_else(|| ccx.tcx().map.local_def_id(node_id)),
2126 ccx.record_translation_item_as_generated(TransItem::Fn{
2128 substs: ccx.tcx().mk_substs(ccx.tcx().erase_regions(param_substs)),
2133 /// Creates an LLVM function corresponding to a source language function.
2134 pub fn trans_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2138 param_substs: &'tcx Substs<'tcx>,
2140 attrs: &[ast::Attribute]) {
2141 let _s = StatRecorder::new(ccx, ccx.tcx().map.path_to_string(id).to_string());
2142 debug!("trans_fn(param_substs={:?})", param_substs);
2143 let _icx = push_ctxt("trans_fn");
2144 let fn_ty = ccx.tcx().node_id_to_type(id);
2145 let fn_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &fn_ty);
2146 let sig = fn_ty.fn_sig();
2147 let sig = ccx.tcx().erase_late_bound_regions(&sig);
2148 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
2149 let output_type = sig.output;
2150 let abi = fn_ty.fn_abi();
2160 closure::ClosureEnv::NotClosure);
2163 pub fn trans_enum_variant<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2164 ctor_id: ast::NodeId,
2166 param_substs: &'tcx Substs<'tcx>,
2167 llfndecl: ValueRef) {
2168 let _icx = push_ctxt("trans_enum_variant");
2170 trans_enum_variant_or_tuple_like_struct(ccx, ctor_id, disr, param_substs, llfndecl);
2173 pub fn trans_named_tuple_constructor<'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
2176 args: callee::CallArgs,
2178 debug_loc: DebugLoc)
2179 -> Result<'blk, 'tcx> {
2181 let ccx = bcx.fcx.ccx;
2183 let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
2184 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
2185 let result_ty = sig.output.unwrap();
2187 // Get location to store the result. If the user does not care about
2188 // the result, just make a stack slot
2189 let llresult = match dest {
2190 expr::SaveIn(d) => d,
2192 if !type_is_zero_size(ccx, result_ty) {
2193 let llresult = alloc_ty(bcx, result_ty, "constructor_result");
2194 call_lifetime_start(bcx, llresult);
2197 C_undef(type_of::type_of(ccx, result_ty).ptr_to())
2202 if !type_is_zero_size(ccx, result_ty) {
2204 callee::ArgExprs(exprs) => {
2205 let fields = exprs.iter().map(|x| &**x).enumerate().collect::<Vec<_>>();
2206 bcx = expr::trans_adt(bcx,
2211 expr::SaveIn(llresult),
2214 _ => ccx.sess().bug("expected expr as arguments for variant/struct tuple constructor"),
2217 // Just eval all the expressions (if any). Since expressions in Rust can have arbitrary
2218 // contents, there could be side-effects we need from them.
2220 callee::ArgExprs(exprs) => {
2222 bcx = expr::trans_into(bcx, expr, expr::Ignore);
2229 // If the caller doesn't care about the result
2230 // drop the temporary we made
2231 let bcx = match dest {
2232 expr::SaveIn(_) => bcx,
2234 let bcx = glue::drop_ty(bcx, llresult, result_ty, debug_loc);
2235 if !type_is_zero_size(ccx, result_ty) {
2236 call_lifetime_end(bcx, llresult);
2242 Result::new(bcx, llresult)
2245 pub fn trans_tuple_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2246 ctor_id: ast::NodeId,
2247 param_substs: &'tcx Substs<'tcx>,
2248 llfndecl: ValueRef) {
2249 let _icx = push_ctxt("trans_tuple_struct");
2251 trans_enum_variant_or_tuple_like_struct(ccx, ctor_id, Disr(0), param_substs, llfndecl);
2254 fn trans_enum_variant_or_tuple_like_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2255 ctor_id: ast::NodeId,
2257 param_substs: &'tcx Substs<'tcx>,
2258 llfndecl: ValueRef) {
2259 let ctor_ty = ccx.tcx().node_id_to_type(ctor_id);
2260 let ctor_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &ctor_ty);
2262 let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
2263 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
2264 let arg_tys = sig.inputs;
2265 let result_ty = sig.output;
2267 let (arena, fcx): (TypedArena<_>, FunctionContext);
2268 arena = TypedArena::new();
2269 fcx = new_fn_ctxt(ccx,
2277 let bcx = init_function(&fcx, false, result_ty);
2279 assert!(!fcx.needs_ret_allocas);
2281 if !type_is_zero_size(fcx.ccx, result_ty.unwrap()) {
2282 let dest = fcx.get_ret_slot(bcx, result_ty, "eret_slot");
2283 let dest_val = adt::MaybeSizedValue::sized(dest); // Can return unsized value
2284 let repr = adt::represent_type(ccx, result_ty.unwrap());
2285 let mut llarg_idx = fcx.arg_offset() as c_uint;
2286 for (i, arg_ty) in arg_tys.into_iter().enumerate() {
2287 let lldestptr = adt::trans_field_ptr(bcx, &*repr, dest_val, Disr::from(disr), i);
2288 if common::type_is_fat_ptr(bcx.tcx(), arg_ty) {
2290 get_param(fcx.llfn, llarg_idx),
2291 expr::get_dataptr(bcx, lldestptr));
2293 get_param(fcx.llfn, llarg_idx + 1),
2294 expr::get_meta(bcx, lldestptr));
2297 let arg = get_param(fcx.llfn, llarg_idx);
2300 if arg_is_indirect(ccx, arg_ty) {
2301 memcpy_ty(bcx, lldestptr, arg, arg_ty);
2303 store_ty(bcx, arg, lldestptr, arg_ty);
2307 adt::trans_set_discr(bcx, &*repr, dest, disr);
2310 finish_fn(&fcx, bcx, result_ty, DebugLoc::None);
2313 fn enum_variant_size_lint(ccx: &CrateContext, enum_def: &hir::EnumDef, sp: Span, id: ast::NodeId) {
2314 let mut sizes = Vec::new(); // does no allocation if no pushes, thankfully
2316 let print_info = ccx.sess().print_enum_sizes();
2318 let levels = ccx.tcx().node_lint_levels.borrow();
2319 let lint_id = lint::LintId::of(lint::builtin::VARIANT_SIZE_DIFFERENCES);
2320 let lvlsrc = levels.get(&(id, lint_id));
2321 let is_allow = lvlsrc.map_or(true, |&(lvl, _)| lvl == lint::Allow);
2323 if is_allow && !print_info {
2324 // we're not interested in anything here
2328 let ty = ccx.tcx().node_id_to_type(id);
2329 let avar = adt::represent_type(ccx, ty);
2331 adt::General(_, ref variants, _) => {
2332 for var in variants {
2334 for field in var.fields.iter().skip(1) {
2335 // skip the discriminant
2336 size += llsize_of_real(ccx, sizing_type_of(ccx, *field));
2341 _ => { /* its size is either constant or unimportant */ }
2344 let (largest, slargest, largest_index) = sizes.iter().enumerate().fold((0, 0, 0),
2345 |(l, s, li), (idx, &size)|
2348 } else if size > s {
2355 // FIXME(#30505) Should use logging for this.
2357 let llty = type_of::sizing_type_of(ccx, ty);
2359 let sess = &ccx.tcx().sess;
2360 sess.span_note_without_error(sp,
2361 &*format!("total size: {} bytes", llsize_of_real(ccx, llty)));
2363 adt::General(..) => {
2364 for (i, var) in enum_def.variants.iter().enumerate() {
2367 .span_note_without_error(var.span,
2368 &*format!("variant data: {} bytes", sizes[i]));
2375 // we only warn if the largest variant is at least thrice as large as
2376 // the second-largest.
2377 if !is_allow && largest > slargest * 3 && slargest > 0 {
2378 // Use lint::raw_emit_lint rather than sess.add_lint because the lint-printing
2379 // pass for the latter already ran.
2380 lint::raw_struct_lint(&ccx.tcx().sess,
2381 &ccx.tcx().sess.lint_store.borrow(),
2382 lint::builtin::VARIANT_SIZE_DIFFERENCES,
2385 &format!("enum variant is more than three times larger ({} bytes) \
2386 than the next largest (ignoring padding)",
2388 .span_note(enum_def.variants[largest_index].span,
2389 "this variant is the largest")
2394 pub fn llvm_linkage_by_name(name: &str) -> Option<Linkage> {
2395 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2396 // applicable to variable declarations and may not really make sense for
2397 // Rust code in the first place but whitelist them anyway and trust that
2398 // the user knows what s/he's doing. Who knows, unanticipated use cases
2399 // may pop up in the future.
2401 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2402 // and don't have to be, LLVM treats them as no-ops.
2404 "appending" => Some(llvm::AppendingLinkage),
2405 "available_externally" => Some(llvm::AvailableExternallyLinkage),
2406 "common" => Some(llvm::CommonLinkage),
2407 "extern_weak" => Some(llvm::ExternalWeakLinkage),
2408 "external" => Some(llvm::ExternalLinkage),
2409 "internal" => Some(llvm::InternalLinkage),
2410 "linkonce" => Some(llvm::LinkOnceAnyLinkage),
2411 "linkonce_odr" => Some(llvm::LinkOnceODRLinkage),
2412 "private" => Some(llvm::PrivateLinkage),
2413 "weak" => Some(llvm::WeakAnyLinkage),
2414 "weak_odr" => Some(llvm::WeakODRLinkage),
2420 /// Enum describing the origin of an LLVM `Value`, for linkage purposes.
2421 #[derive(Copy, Clone)]
2422 pub enum ValueOrigin {
2423 /// The LLVM `Value` is in this context because the corresponding item was
2424 /// assigned to the current compilation unit.
2425 OriginalTranslation,
2426 /// The `Value`'s corresponding item was assigned to some other compilation
2427 /// unit, but the `Value` was translated in this context anyway because the
2428 /// item is marked `#[inline]`.
2432 /// Set the appropriate linkage for an LLVM `ValueRef` (function or global).
2433 /// If the `llval` is the direct translation of a specific Rust item, `id`
2434 /// should be set to the `NodeId` of that item. (This mapping should be
2435 /// 1-to-1, so monomorphizations and drop/visit glue should have `id` set to
2436 /// `None`.) `llval_origin` indicates whether `llval` is the translation of an
2437 /// item assigned to `ccx`'s compilation unit or an inlined copy of an item
2438 /// assigned to a different compilation unit.
2439 pub fn update_linkage(ccx: &CrateContext,
2441 id: Option<ast::NodeId>,
2442 llval_origin: ValueOrigin) {
2443 match llval_origin {
2445 // `llval` is a translation of an item defined in a separate
2446 // compilation unit. This only makes sense if there are at least
2447 // two compilation units.
2448 assert!(ccx.sess().opts.cg.codegen_units > 1);
2449 // `llval` is a copy of something defined elsewhere, so use
2450 // `AvailableExternallyLinkage` to avoid duplicating code in the
2452 llvm::SetLinkage(llval, llvm::AvailableExternallyLinkage);
2455 OriginalTranslation => {},
2458 if let Some(id) = id {
2459 let item = ccx.tcx().map.get(id);
2460 if let hir_map::NodeItem(i) = item {
2461 if let Some(name) = attr::first_attr_value_str_by_name(&i.attrs, "linkage") {
2462 if let Some(linkage) = llvm_linkage_by_name(&name) {
2463 llvm::SetLinkage(llval, linkage);
2465 ccx.sess().span_fatal(i.span, "invalid linkage specified");
2473 Some(id) if ccx.reachable().contains(&id) => {
2474 llvm::SetLinkage(llval, llvm::ExternalLinkage);
2477 // `id` does not refer to an item in `ccx.reachable`.
2478 if ccx.sess().opts.cg.codegen_units > 1 {
2479 llvm::SetLinkage(llval, llvm::ExternalLinkage);
2481 llvm::SetLinkage(llval, llvm::InternalLinkage);
2487 fn set_global_section(ccx: &CrateContext, llval: ValueRef, i: &hir::Item) {
2488 match attr::first_attr_value_str_by_name(&i.attrs, "link_section") {
2490 if contains_null(§) {
2491 ccx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", §));
2494 let buf = CString::new(sect.as_bytes()).unwrap();
2495 llvm::LLVMSetSection(llval, buf.as_ptr());
2502 pub fn trans_item(ccx: &CrateContext, item: &hir::Item) {
2503 let _icx = push_ctxt("trans_item");
2505 let from_external = ccx.external_srcs().borrow().contains_key(&item.id);
2508 hir::ItemFn(ref decl, _, _, abi, ref generics, ref body) => {
2509 if !generics.is_type_parameterized() {
2510 let trans_everywhere = attr::requests_inline(&item.attrs);
2511 // Ignore `trans_everywhere` for cross-crate inlined items
2512 // (`from_external`). `trans_item` will be called once for each
2513 // compilation unit that references the item, so it will still get
2514 // translated everywhere it's needed.
2515 for (ref ccx, is_origin) in ccx.maybe_iter(!from_external && trans_everywhere) {
2516 let llfn = get_item_val(ccx, item.id);
2517 let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
2519 foreign::trans_rust_fn_with_foreign_abi(ccx,
2536 set_global_section(ccx, llfn, item);
2546 if is_entry_fn(ccx.sess(), item.id) {
2547 create_entry_wrapper(ccx, item.span, llfn);
2548 // check for the #[rustc_error] annotation, which forces an
2549 // error in trans. This is used to write compile-fail tests
2550 // that actually test that compilation succeeds without
2551 // reporting an error.
2552 let item_def_id = ccx.tcx().map.local_def_id(item.id);
2553 if ccx.tcx().has_attr(item_def_id, "rustc_error") {
2554 ccx.tcx().sess.span_fatal(item.span, "compilation successful");
2560 hir::ItemImpl(_, _, ref generics, _, _, ref impl_items) => {
2561 meth::trans_impl(ccx, item.name, impl_items, generics, item.id);
2563 hir::ItemMod(_) => {
2564 // modules have no equivalent at runtime, they just affect
2565 // the mangled names of things contained within
2567 hir::ItemEnum(ref enum_definition, ref gens) => {
2568 if gens.ty_params.is_empty() {
2569 // sizes only make sense for non-generic types
2571 enum_variant_size_lint(ccx, enum_definition, item.span, item.id);
2574 hir::ItemConst(..) => {}
2575 hir::ItemStatic(_, m, ref expr) => {
2576 let g = match consts::trans_static(ccx, m, expr, item.id, &item.attrs) {
2578 Err(err) => ccx.tcx().sess.span_fatal(expr.span, &err.description()),
2580 set_global_section(ccx, g, item);
2581 update_linkage(ccx, g, Some(item.id), OriginalTranslation);
2583 hir::ItemForeignMod(ref foreign_mod) => {
2584 foreign::trans_foreign_mod(ccx, foreign_mod);
2586 hir::ItemTrait(..) => {}
2593 // only use this for foreign function ABIs and glue, use `register_fn` for Rust functions
2594 pub fn register_fn_llvmty(ccx: &CrateContext,
2597 node_id: ast::NodeId,
2601 debug!("register_fn_llvmty id={} sym={}", node_id, sym);
2603 let llfn = declare::define_fn(ccx, &sym[..], cc, llfty,
2604 ty::FnConverging(ccx.tcx().mk_nil())).unwrap_or_else(||{
2605 ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym));
2607 finish_register_fn(ccx, sym, node_id);
2611 fn finish_register_fn(ccx: &CrateContext, sym: String, node_id: ast::NodeId) {
2612 ccx.item_symbols().borrow_mut().insert(node_id, sym);
2615 fn register_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2618 node_id: ast::NodeId,
2619 node_type: Ty<'tcx>)
2621 if let ty::TyBareFn(_, ref f) = node_type.sty {
2622 if f.abi != Rust && f.abi != RustCall {
2623 ccx.sess().span_bug(sp,
2624 &format!("only the `{}` or `{}` calling conventions are valid \
2625 for this function; `{}` was specified",
2631 ccx.sess().span_bug(sp, "expected bare rust function")
2634 let llfn = declare::define_rust_fn(ccx, &sym[..], node_type).unwrap_or_else(|| {
2635 ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym));
2637 finish_register_fn(ccx, sym, node_id);
2641 pub fn is_entry_fn(sess: &Session, node_id: ast::NodeId) -> bool {
2642 match *sess.entry_fn.borrow() {
2643 Some((entry_id, _)) => node_id == entry_id,
2648 /// Create the `main` function which will initialise the rust runtime and call users’ main
2650 pub fn create_entry_wrapper(ccx: &CrateContext, sp: Span, main_llfn: ValueRef) {
2651 let et = ccx.sess().entry_type.get().unwrap();
2653 config::EntryMain => {
2654 create_entry_fn(ccx, sp, main_llfn, true);
2656 config::EntryStart => create_entry_fn(ccx, sp, main_llfn, false),
2657 config::EntryNone => {} // Do nothing.
2660 fn create_entry_fn(ccx: &CrateContext,
2662 rust_main: ValueRef,
2663 use_start_lang_item: bool) {
2664 let llfty = Type::func(&[ccx.int_type(), Type::i8p(ccx).ptr_to()], &ccx.int_type());
2666 let llfn = declare::define_cfn(ccx, "main", llfty, ccx.tcx().mk_nil()).unwrap_or_else(|| {
2667 // FIXME: We should be smart and show a better diagnostic here.
2668 ccx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
2669 .help("did you use #[no_mangle] on `fn main`? Use #[start] instead")
2671 ccx.sess().abort_if_errors();
2676 llvm::LLVMAppendBasicBlockInContext(ccx.llcx(), llfn, "top\0".as_ptr() as *const _)
2678 let bld = ccx.raw_builder();
2680 llvm::LLVMPositionBuilderAtEnd(bld, llbb);
2682 debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx);
2684 let (start_fn, args) = if use_start_lang_item {
2685 let start_def_id = match ccx.tcx().lang_items.require(StartFnLangItem) {
2688 ccx.sess().fatal(&s[..]);
2691 let start_fn = if let Some(start_node_id) = ccx.tcx()
2693 .as_local_node_id(start_def_id) {
2694 get_item_val(ccx, start_node_id)
2696 let start_fn_type = ccx.tcx().lookup_item_type(start_def_id).ty;
2697 trans_external_path(ccx, start_def_id, start_fn_type)
2700 let opaque_rust_main =
2701 llvm::LLVMBuildPointerCast(bld,
2703 Type::i8p(ccx).to_ref(),
2704 "rust_main\0".as_ptr() as *const _);
2706 vec![opaque_rust_main, get_param(llfn, 0), get_param(llfn, 1)]
2710 debug!("using user-defined start fn");
2711 let args = vec![get_param(llfn, 0 as c_uint), get_param(llfn, 1 as c_uint)];
2716 let result = llvm::LLVMBuildCall(bld,
2719 args.len() as c_uint,
2722 llvm::LLVMBuildRet(bld, result);
2727 fn exported_name<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2730 attrs: &[ast::Attribute])
2732 match ccx.external_srcs().borrow().get(&id) {
2734 let sym = ccx.sess().cstore.item_symbol(did);
2735 debug!("found item {} in other crate...", sym);
2741 match attr::find_export_name_attr(ccx.sess().diagnostic(), attrs) {
2742 // Use provided name
2743 Some(name) => name.to_string(),
2745 let path = ccx.tcx().map.def_path_from_id(id);
2746 if attr::contains_name(attrs, "no_mangle") {
2748 path.last().unwrap().data.to_string()
2750 match weak_lang_items::link_name(attrs) {
2751 Some(name) => name.to_string(),
2753 // Usual name mangling
2754 mangle_exported_name(ccx, path, ty, id)
2762 fn contains_null(s: &str) -> bool {
2763 s.bytes().any(|b| b == 0)
2766 pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
2767 debug!("get_item_val(id=`{}`)", id);
2769 match ccx.item_vals().borrow().get(&id).cloned() {
2770 Some(v) => return v,
2774 let item = ccx.tcx().map.get(id);
2775 debug!("get_item_val: id={} item={:?}", id, item);
2776 let val = match item {
2777 hir_map::NodeItem(i) => {
2778 let ty = ccx.tcx().node_id_to_type(i.id);
2779 let sym = || exported_name(ccx, id, ty, &i.attrs);
2781 let v = match i.node {
2782 hir::ItemStatic(..) => {
2783 // If this static came from an external crate, then
2784 // we need to get the symbol from metadata instead of
2785 // using the current crate's name/version
2786 // information in the hash of the symbol
2788 debug!("making {}", sym);
2790 // Create the global before evaluating the initializer;
2791 // this is necessary to allow recursive statics.
2792 let llty = type_of(ccx, ty);
2793 let g = declare::define_global(ccx, &sym[..], llty).unwrap_or_else(|| {
2795 .span_fatal(i.span, &format!("symbol `{}` is already defined", sym))
2798 ccx.item_symbols().borrow_mut().insert(i.id, sym);
2802 hir::ItemFn(_, _, _, abi, _, _) => {
2804 let llfn = if abi == Rust {
2805 register_fn(ccx, i.span, sym, i.id, ty)
2807 foreign::register_rust_fn_with_foreign_abi(ccx, i.span, sym, i.id)
2809 attributes::from_fn_attrs(ccx, &i.attrs, llfn);
2813 _ => ccx.sess().bug("get_item_val: weird result in table"),
2819 hir_map::NodeTraitItem(trait_item) => {
2820 debug!("get_item_val(): processing a NodeTraitItem");
2821 match trait_item.node {
2822 hir::MethodTraitItem(_, Some(_)) => {
2823 register_method(ccx, id, &trait_item.attrs, trait_item.span)
2826 ccx.sess().span_bug(trait_item.span,
2827 "unexpected variant: trait item other than a provided \
2828 method in get_item_val()");
2833 hir_map::NodeImplItem(impl_item) => {
2834 match impl_item.node {
2835 hir::ImplItemKind::Method(..) => {
2836 register_method(ccx, id, &impl_item.attrs, impl_item.span)
2839 ccx.sess().span_bug(impl_item.span,
2840 "unexpected variant: non-method impl item in \
2846 hir_map::NodeForeignItem(ni) => {
2848 hir::ForeignItemFn(..) => {
2849 let abi = ccx.tcx().map.get_foreign_abi(id);
2850 let ty = ccx.tcx().node_id_to_type(ni.id);
2851 let name = foreign::link_name(&*ni);
2852 foreign::register_foreign_item_fn(ccx, abi, ty, &name, &ni.attrs)
2854 hir::ForeignItemStatic(..) => {
2855 foreign::register_static(ccx, &*ni)
2860 hir_map::NodeVariant(ref v) => {
2862 let fields = if v.node.data.is_struct() {
2863 ccx.sess().bug("struct variant kind unexpected in get_item_val")
2865 v.node.data.fields()
2867 assert!(!fields.is_empty());
2868 let ty = ccx.tcx().node_id_to_type(id);
2869 let parent = ccx.tcx().map.get_parent(id);
2870 let enm = ccx.tcx().map.expect_item(parent);
2871 let sym = exported_name(ccx, id, ty, &enm.attrs);
2873 llfn = match enm.node {
2874 hir::ItemEnum(_, _) => {
2875 register_fn(ccx, (*v).span, sym, id, ty)
2877 _ => ccx.sess().bug("NodeVariant, shouldn't happen"),
2879 attributes::inline(llfn, attributes::InlineAttr::Hint);
2883 hir_map::NodeStructCtor(struct_def) => {
2884 // Only register the constructor if this is a tuple-like struct.
2885 let ctor_id = if struct_def.is_struct() {
2886 ccx.sess().bug("attempt to register a constructor of a non-tuple-like struct")
2890 let parent = ccx.tcx().map.get_parent(id);
2891 let struct_item = ccx.tcx().map.expect_item(parent);
2892 let ty = ccx.tcx().node_id_to_type(ctor_id);
2893 let sym = exported_name(ccx, id, ty, &struct_item.attrs);
2894 let llfn = register_fn(ccx, struct_item.span, sym, ctor_id, ty);
2895 attributes::inline(llfn, attributes::InlineAttr::Hint);
2900 ccx.sess().bug(&format!("get_item_val(): unexpected variant: {:?}", variant))
2904 // All LLVM globals and functions are initially created as external-linkage
2905 // declarations. If `trans_item`/`trans_fn` later turns the declaration
2906 // into a definition, it adjusts the linkage then (using `update_linkage`).
2908 // The exception is foreign items, which have their linkage set inside the
2909 // call to `foreign::register_*` above. We don't touch the linkage after
2910 // that (`foreign::trans_foreign_mod` doesn't adjust the linkage like the
2911 // other item translation functions do).
2913 ccx.item_vals().borrow_mut().insert(id, val);
2917 fn register_method(ccx: &CrateContext,
2919 attrs: &[ast::Attribute],
2922 let mty = ccx.tcx().node_id_to_type(id);
2924 let sym = exported_name(ccx, id, mty, &attrs);
2926 if let ty::TyBareFn(_, ref f) = mty.sty {
2927 let llfn = if f.abi == Rust || f.abi == RustCall {
2928 register_fn(ccx, span, sym, id, mty)
2930 foreign::register_rust_fn_with_foreign_abi(ccx, span, sym, id)
2932 attributes::from_fn_attrs(ccx, &attrs, llfn);
2935 ccx.sess().span_bug(span, "expected bare rust function");
2939 pub fn write_metadata<'a, 'tcx>(cx: &SharedCrateContext<'a, 'tcx>,
2941 reachable: &NodeSet,
2942 mir_map: &MirMap<'tcx>)
2946 let any_library = cx.sess()
2950 .any(|ty| *ty != config::CrateTypeExecutable);
2955 let cstore = &cx.tcx().sess.cstore;
2956 let metadata = cstore.encode_metadata(cx.tcx(),
2963 let mut compressed = cstore.metadata_encoding_version().to_vec();
2964 compressed.extend_from_slice(&flate::deflate_bytes(&metadata));
2966 let llmeta = C_bytes_in_context(cx.metadata_llcx(), &compressed[..]);
2967 let llconst = C_struct_in_context(cx.metadata_llcx(), &[llmeta], false);
2968 let name = format!("rust_metadata_{}_{}",
2969 cx.link_meta().crate_name,
2970 cx.link_meta().crate_hash);
2971 let buf = CString::new(name).unwrap();
2972 let llglobal = unsafe {
2973 llvm::LLVMAddGlobal(cx.metadata_llmod(), val_ty(llconst).to_ref(), buf.as_ptr())
2976 llvm::LLVMSetInitializer(llglobal, llconst);
2978 cx.tcx().sess.cstore.metadata_section_name(&cx.sess().target.target);
2979 let name = CString::new(name).unwrap();
2980 llvm::LLVMSetSection(llglobal, name.as_ptr())
2985 /// Find any symbols that are defined in one compilation unit, but not declared
2986 /// in any other compilation unit. Give these symbols internal linkage.
2987 fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet<&str>) {
2989 let mut declared = HashSet::new();
2991 // Collect all external declarations in all compilation units.
2992 for ccx in cx.iter() {
2993 for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) {
2994 let linkage = llvm::LLVMGetLinkage(val);
2995 // We only care about external declarations (not definitions)
2996 // and available_externally definitions.
2997 if !(linkage == llvm::ExternalLinkage as c_uint &&
2998 llvm::LLVMIsDeclaration(val) != 0) &&
2999 !(linkage == llvm::AvailableExternallyLinkage as c_uint) {
3003 let name = CStr::from_ptr(llvm::LLVMGetValueName(val))
3006 declared.insert(name);
3010 // Examine each external definition. If the definition is not used in
3011 // any other compilation unit, and is not reachable from other crates,
3012 // then give it internal linkage.
3013 for ccx in cx.iter() {
3014 for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) {
3015 // We only care about external definitions.
3016 if !(llvm::LLVMGetLinkage(val) == llvm::ExternalLinkage as c_uint &&
3017 llvm::LLVMIsDeclaration(val) == 0) {
3021 let name = CStr::from_ptr(llvm::LLVMGetValueName(val))
3024 if !declared.contains(&name) &&
3025 !reachable.contains(str::from_utf8(&name).unwrap()) {
3026 llvm::SetLinkage(val, llvm::InternalLinkage);
3027 llvm::SetDLLStorageClass(val, llvm::DefaultStorageClass);
3034 // Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
3035 // This is required to satisfy `dllimport` references to static data in .rlibs
3036 // when using MSVC linker. We do this only for data, as linker can fix up
3037 // code references on its own.
3038 // See #26591, #27438
3039 fn create_imps(cx: &SharedCrateContext) {
3040 // The x86 ABI seems to require that leading underscores are added to symbol
3041 // names, so we need an extra underscore on 32-bit. There's also a leading
3042 // '\x01' here which disables LLVM's symbol mangling (e.g. no extra
3043 // underscores added in front).
3044 let prefix = if cx.sess().target.target.target_pointer_width == "32" {
3050 for ccx in cx.iter() {
3051 let exported: Vec<_> = iter_globals(ccx.llmod())
3053 llvm::LLVMGetLinkage(val) ==
3054 llvm::ExternalLinkage as c_uint &&
3055 llvm::LLVMIsDeclaration(val) == 0
3059 let i8p_ty = Type::i8p(&ccx);
3060 for val in exported {
3061 let name = CStr::from_ptr(llvm::LLVMGetValueName(val));
3062 let mut imp_name = prefix.as_bytes().to_vec();
3063 imp_name.extend(name.to_bytes());
3064 let imp_name = CString::new(imp_name).unwrap();
3065 let imp = llvm::LLVMAddGlobal(ccx.llmod(),
3067 imp_name.as_ptr() as *const _);
3068 let init = llvm::LLVMConstBitCast(val, i8p_ty.to_ref());
3069 llvm::LLVMSetInitializer(imp, init);
3070 llvm::SetLinkage(imp, llvm::ExternalLinkage);
3078 step: unsafe extern "C" fn(ValueRef) -> ValueRef,
3081 impl Iterator for ValueIter {
3082 type Item = ValueRef;
3084 fn next(&mut self) -> Option<ValueRef> {
3087 self.cur = unsafe { (self.step)(old) };
3095 fn iter_globals(llmod: llvm::ModuleRef) -> ValueIter {
3098 cur: llvm::LLVMGetFirstGlobal(llmod),
3099 step: llvm::LLVMGetNextGlobal,
3104 fn iter_functions(llmod: llvm::ModuleRef) -> ValueIter {
3107 cur: llvm::LLVMGetFirstFunction(llmod),
3108 step: llvm::LLVMGetNextFunction,
3113 /// The context provided lists a set of reachable ids as calculated by
3114 /// middle::reachable, but this contains far more ids and symbols than we're
3115 /// actually exposing from the object file. This function will filter the set in
3116 /// the context to the set of ids which correspond to symbols that are exposed
3117 /// from the object file being generated.
3119 /// This list is later used by linkers to determine the set of symbols needed to
3120 /// be exposed from a dynamic library and it's also encoded into the metadata.
3121 pub fn filter_reachable_ids(ccx: &SharedCrateContext) -> NodeSet {
3122 ccx.reachable().iter().map(|x| *x).filter(|id| {
3123 // First, only worry about nodes which have a symbol name
3124 ccx.item_symbols().borrow().contains_key(id)
3126 // Next, we want to ignore some FFI functions that are not exposed from
3127 // this crate. Reachable FFI functions can be lumped into two
3130 // 1. Those that are included statically via a static library
3131 // 2. Those included otherwise (e.g. dynamically or via a framework)
3133 // Although our LLVM module is not literally emitting code for the
3134 // statically included symbols, it's an export of our library which
3135 // needs to be passed on to the linker and encoded in the metadata.
3137 // As a result, if this id is an FFI item (foreign item) then we only
3138 // let it through if it's included statically.
3139 match ccx.tcx().map.get(id) {
3140 hir_map::NodeForeignItem(..) => {
3141 ccx.sess().cstore.is_statically_included_foreign_item(id)
3148 pub fn trans_crate<'tcx>(tcx: &ty::ctxt<'tcx>,
3149 mir_map: &MirMap<'tcx>,
3150 analysis: ty::CrateAnalysis)
3151 -> CrateTranslation {
3152 let _task = tcx.dep_graph.in_task(DepNode::TransCrate);
3154 // Be careful with this krate: obviously it gives access to the
3155 // entire contents of the krate. So if you push any subtasks of
3156 // `TransCrate`, you need to be careful to register "reads" of the
3157 // particular items that will be processed.
3158 let krate = tcx.map.krate();
3160 let ty::CrateAnalysis { export_map, reachable, name, .. } = analysis;
3162 let check_overflow = if let Some(v) = tcx.sess.opts.debugging_opts.force_overflow_checks {
3165 tcx.sess.opts.debug_assertions
3168 let check_dropflag = if let Some(v) = tcx.sess.opts.debugging_opts.force_dropflag_checks {
3171 tcx.sess.opts.debug_assertions
3174 // Before we touch LLVM, make sure that multithreading is enabled.
3176 use std::sync::Once;
3177 static INIT: Once = Once::new();
3178 static mut POISONED: bool = false;
3180 if llvm::LLVMStartMultithreaded() != 1 {
3181 // use an extra bool to make sure that all future usage of LLVM
3182 // cannot proceed despite the Once not running more than once.
3186 ::back::write::configure_llvm(&tcx.sess);
3190 tcx.sess.bug("couldn't enable multi-threaded LLVM");
3194 let link_meta = link::build_link_meta(&tcx.sess, krate, name);
3196 let codegen_units = tcx.sess.opts.cg.codegen_units;
3197 let shared_ccx = SharedCrateContext::new(&link_meta.crate_name,
3209 let ccx = shared_ccx.get_ccx(0);
3211 // First, verify intrinsics.
3212 intrinsic::check_intrinsics(&ccx);
3214 collect_translation_items(&ccx);
3216 // Next, translate all items. See `TransModVisitor` for
3217 // details on why we walk in this particular way.
3219 let _icx = push_ctxt("text");
3220 intravisit::walk_mod(&mut TransItemsWithinModVisitor { ccx: &ccx }, &krate.module);
3221 krate.visit_all_items(&mut TransModVisitor { ccx: &ccx });
3224 collector::print_collection_results(&ccx);
3227 for ccx in shared_ccx.iter() {
3228 if ccx.sess().opts.debuginfo != NoDebugInfo {
3229 debuginfo::finalize(&ccx);
3231 for &(old_g, new_g) in ccx.statics_to_rauw().borrow().iter() {
3233 let bitcast = llvm::LLVMConstPointerCast(new_g, llvm::LLVMTypeOf(old_g));
3234 llvm::LLVMReplaceAllUsesWith(old_g, bitcast);
3235 llvm::LLVMDeleteGlobal(old_g);
3240 let reachable_symbol_ids = filter_reachable_ids(&shared_ccx);
3242 // Translate the metadata.
3243 let metadata = time(tcx.sess.time_passes(), "write metadata", || {
3244 write_metadata(&shared_ccx, krate, &reachable_symbol_ids, mir_map)
3247 if shared_ccx.sess().trans_stats() {
3248 let stats = shared_ccx.stats();
3249 println!("--- trans stats ---");
3250 println!("n_glues_created: {}", stats.n_glues_created.get());
3251 println!("n_null_glues: {}", stats.n_null_glues.get());
3252 println!("n_real_glues: {}", stats.n_real_glues.get());
3254 println!("n_fns: {}", stats.n_fns.get());
3255 println!("n_monos: {}", stats.n_monos.get());
3256 println!("n_inlines: {}", stats.n_inlines.get());
3257 println!("n_closures: {}", stats.n_closures.get());
3258 println!("fn stats:");
3259 stats.fn_stats.borrow_mut().sort_by(|&(_, insns_a), &(_, insns_b)| {
3260 insns_b.cmp(&insns_a)
3262 for tuple in stats.fn_stats.borrow().iter() {
3264 (ref name, insns) => {
3265 println!("{} insns, {}", insns, *name);
3270 if shared_ccx.sess().count_llvm_insns() {
3271 for (k, v) in shared_ccx.stats().llvm_insns.borrow().iter() {
3272 println!("{:7} {}", *v, *k);
3276 let modules = shared_ccx.iter()
3277 .map(|ccx| ModuleTranslation { llcx: ccx.llcx(), llmod: ccx.llmod() })
3280 let sess = shared_ccx.sess();
3281 let mut reachable_symbols = reachable_symbol_ids.iter().map(|id| {
3282 shared_ccx.item_symbols().borrow()[id].to_string()
3283 }).collect::<Vec<_>>();
3284 if sess.entry_fn.borrow().is_some() {
3285 reachable_symbols.push("main".to_string());
3288 // For the purposes of LTO, we add to the reachable set all of the upstream
3289 // reachable extern fns. These functions are all part of the public ABI of
3290 // the final product, so LTO needs to preserve them.
3292 for cnum in sess.cstore.crates() {
3293 let syms = sess.cstore.reachable_ids(cnum);
3294 reachable_symbols.extend(syms.into_iter().filter(|did| {
3295 sess.cstore.is_extern_fn(shared_ccx.tcx(), *did) ||
3296 sess.cstore.is_static(*did)
3298 sess.cstore.item_symbol(did)
3303 if codegen_units > 1 {
3304 internalize_symbols(&shared_ccx,
3305 &reachable_symbols.iter().map(|x| &x[..]).collect());
3308 if sess.target.target.options.is_like_msvc &&
3309 sess.crate_types.borrow().iter().any(|ct| *ct == config::CrateTypeRlib) {
3310 create_imps(&shared_ccx);
3313 let metadata_module = ModuleTranslation {
3314 llcx: shared_ccx.metadata_llcx(),
3315 llmod: shared_ccx.metadata_llmod(),
3317 let no_builtins = attr::contains_name(&krate.attrs, "no_builtins");
3319 assert_dep_graph::assert_dep_graph(tcx);
3323 metadata_module: metadata_module,
3326 reachable: reachable_symbols,
3327 no_builtins: no_builtins,
3331 /// We visit all the items in the krate and translate them. We do
3332 /// this in two walks. The first walk just finds module items. It then
3333 /// walks the full contents of those module items and translates all
3334 /// the items within. Note that this entire process is O(n). The
3335 /// reason for this two phased walk is that each module is
3336 /// (potentially) placed into a distinct codegen-unit. This walk also
3337 /// ensures that the immediate contents of each module is processed
3338 /// entirely before we proceed to find more modules, helping to ensure
3339 /// an equitable distribution amongst codegen-units.
3340 pub struct TransModVisitor<'a, 'tcx: 'a> {
3341 pub ccx: &'a CrateContext<'a, 'tcx>,
3344 impl<'a, 'tcx, 'v> Visitor<'v> for TransModVisitor<'a, 'tcx> {
3345 fn visit_item(&mut self, i: &hir::Item) {
3347 hir::ItemMod(_) => {
3348 let item_ccx = self.ccx.rotate();
3349 intravisit::walk_item(&mut TransItemsWithinModVisitor { ccx: &item_ccx }, i);
3356 /// Translates all the items within a given module. Expects owner to
3357 /// invoke `walk_item` on a module item. Ignores nested modules.
3358 pub struct TransItemsWithinModVisitor<'a, 'tcx: 'a> {
3359 pub ccx: &'a CrateContext<'a, 'tcx>,
3362 impl<'a, 'tcx, 'v> Visitor<'v> for TransItemsWithinModVisitor<'a, 'tcx> {
3363 fn visit_nested_item(&mut self, item_id: hir::ItemId) {
3364 self.visit_item(self.ccx.tcx().map.expect_item(item_id.id));
3367 fn visit_item(&mut self, i: &hir::Item) {
3369 hir::ItemMod(..) => {
3370 // skip modules, they will be uncovered by the TransModVisitor
3373 let def_id = self.ccx.tcx().map.local_def_id(i.id);
3374 let tcx = self.ccx.tcx();
3376 // Create a subtask for trans'ing a particular item. We are
3377 // giving `trans_item` access to this item, so also record a read.
3378 tcx.dep_graph.with_task(DepNode::TransCrateItem(def_id), || {
3379 tcx.dep_graph.read(DepNode::Hir(def_id));
3381 // We are going to be accessing various tables
3382 // generated by TypeckItemBody; we also assume
3383 // that the body passes type check. These tables
3384 // are not individually tracked, so just register
3386 tcx.dep_graph.read(DepNode::TypeckItemBody(def_id));
3388 trans_item(self.ccx, i);
3391 intravisit::walk_item(self, i);
3397 fn collect_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
3398 let time_passes = ccx.sess().time_passes();
3400 let collection_mode = match ccx.sess().opts.debugging_opts.print_trans_items {
3402 let mode_string = s.to_lowercase();
3403 let mode_string = mode_string.trim();
3404 if mode_string == "eager" {
3405 TransItemCollectionMode::Eager
3407 if mode_string != "lazy" {
3408 let message = format!("Unknown codegen-item collection mode '{}'. \
3409 Falling back to 'lazy' mode.",
3411 ccx.sess().warn(&message);
3414 TransItemCollectionMode::Lazy
3417 None => TransItemCollectionMode::Lazy
3420 let items = time(time_passes, "translation item collection", || {
3421 collector::collect_crate_translation_items(&ccx, collection_mode)
3424 if ccx.sess().opts.debugging_opts.print_trans_items.is_some() {
3425 let mut item_keys: Vec<_> = items.iter()
3426 .map(|i| i.to_string(ccx))
3430 for item in item_keys {
3431 println!("TRANS_ITEM {}", item);
3434 let mut ccx_map = ccx.translation_items().borrow_mut();
3437 ccx_map.insert(cgi, TransItemState::PredictedButNotGenerated);