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::Substs;
45 use middle::ty::{self, Ty, TypeFoldable};
46 use rustc::dep_graph::DepNode;
47 use rustc::front::map as hir_map;
48 use rustc::util::common::time;
49 use rustc_mir::mir_map::MirMap;
50 use session::config::{self, NoDebugInfo, FullDebugInfo};
54 use trans::assert_dep_graph;
55 use trans::attributes;
57 use trans::builder::{Builder, noname};
59 use trans::cleanup::{self, CleanupMethods, DropHint};
61 use trans::common::{Block, C_bool, C_bytes_in_context, C_i32, C_int, C_uint, C_integral};
62 use trans::common::{C_null, C_struct_in_context, C_u64, C_u8, C_undef};
63 use trans::common::{CrateContext, DropFlagHintsMap, Field, FunctionContext};
64 use trans::common::{Result, NodeIdAndSpan, VariantInfo};
65 use trans::common::{node_id_type, return_type_is_void};
66 use trans::common::{type_is_immediate, type_is_zero_size, val_ty};
69 use trans::context::SharedCrateContext;
70 use trans::controlflow;
72 use trans::debuginfo::{self, DebugLoc, ToDebugLoc};
79 use trans::machine::{llsize_of, llsize_of_real};
82 use trans::monomorphize;
84 use trans::type_::Type;
86 use trans::type_of::*;
87 use trans::value::Value;
88 use util::common::indenter;
89 use util::sha2::Sha256;
90 use util::nodemap::{NodeMap, NodeSet};
92 use arena::TypedArena;
94 use std::ffi::{CStr, CString};
95 use std::cell::{Cell, RefCell};
96 use std::collections::{HashMap, HashSet};
98 use std::{i8, i16, i32, i64};
99 use syntax::abi::{Rust, RustCall, RustIntrinsic, PlatformIntrinsic, Abi};
100 use syntax::codemap::Span;
101 use syntax::parse::token::InternedString;
102 use syntax::attr::AttrMetaMethods;
105 use rustc_front::intravisit::{self, Visitor};
106 use rustc_front::hir;
110 static TASK_LOCAL_INSN_KEY: RefCell<Option<Vec<&'static str>>> = {
115 pub fn with_insn_ctxt<F>(blk: F)
116 where F: FnOnce(&[&'static str])
118 TASK_LOCAL_INSN_KEY.with(move |slot| {
119 slot.borrow().as_ref().map(move |s| blk(s));
123 pub fn init_insn_ctxt() {
124 TASK_LOCAL_INSN_KEY.with(|slot| {
125 *slot.borrow_mut() = Some(Vec::new());
129 pub struct _InsnCtxt {
130 _cannot_construct_outside_of_this_module: (),
133 impl Drop for _InsnCtxt {
135 TASK_LOCAL_INSN_KEY.with(|slot| {
136 match slot.borrow_mut().as_mut() {
146 pub fn push_ctxt(s: &'static str) -> _InsnCtxt {
147 debug!("new InsnCtxt: {}", s);
148 TASK_LOCAL_INSN_KEY.with(|slot| {
149 match slot.borrow_mut().as_mut() {
150 Some(ctx) => ctx.push(s),
155 _cannot_construct_outside_of_this_module: (),
159 pub struct StatRecorder<'a, 'tcx: 'a> {
160 ccx: &'a CrateContext<'a, 'tcx>,
161 name: Option<String>,
165 impl<'a, 'tcx> StatRecorder<'a, 'tcx> {
166 pub fn new(ccx: &'a CrateContext<'a, 'tcx>, name: String) -> StatRecorder<'a, 'tcx> {
167 let istart = ccx.stats().n_llvm_insns.get();
176 impl<'a, 'tcx> Drop for StatRecorder<'a, 'tcx> {
178 if self.ccx.sess().trans_stats() {
179 let iend = self.ccx.stats().n_llvm_insns.get();
184 .push((self.name.take().unwrap(), iend - self.istart));
185 self.ccx.stats().n_fns.set(self.ccx.stats().n_fns.get() + 1);
186 // Reset LLVM insn count to avoid compound costs.
187 self.ccx.stats().n_llvm_insns.set(self.istart);
192 fn get_extern_rust_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
197 match ccx.externs().borrow().get(name) {
198 Some(n) => return *n,
202 let f = declare::declare_rust_fn(ccx, name, fn_ty);
204 let attrs = ccx.sess().cstore.item_attrs(did);
205 attributes::from_fn_attrs(ccx, &attrs[..], f);
207 ccx.externs().borrow_mut().insert(name.to_string(), f);
211 pub fn self_type_for_closure<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
215 let closure_kind = ccx.tcx().closure_kind(closure_id);
217 ty::FnClosureKind => {
218 ccx.tcx().mk_imm_ref(ccx.tcx().mk_region(ty::ReStatic), fn_ty)
220 ty::FnMutClosureKind => {
221 ccx.tcx().mk_mut_ref(ccx.tcx().mk_region(ty::ReStatic), fn_ty)
223 ty::FnOnceClosureKind => fn_ty,
227 pub fn kind_for_closure(ccx: &CrateContext, closure_id: DefId) -> ty::ClosureKind {
228 *ccx.tcx().tables.borrow().closure_kinds.get(&closure_id).unwrap()
231 pub fn get_extern_const<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
235 let name = ccx.sess().cstore.item_symbol(did);
236 let ty = type_of(ccx, t);
237 match ccx.externs().borrow_mut().get(&name) {
238 Some(n) => return *n,
241 // FIXME(nagisa): perhaps the map of externs could be offloaded to llvm somehow?
242 // FIXME(nagisa): investigate whether it can be changed into define_global
243 let c = declare::declare_global(ccx, &name[..], ty);
244 // Thread-local statics in some other crate need to *always* be linked
245 // against in a thread-local fashion, so we need to be sure to apply the
246 // thread-local attribute locally if it was present remotely. If we
247 // don't do this then linker errors can be generated where the linker
248 // complains that one object files has a thread local version of the
249 // symbol and another one doesn't.
250 for attr in ccx.tcx().get_attrs(did).iter() {
251 if attr.check_name("thread_local") {
252 llvm::set_thread_local(c, true);
255 if ccx.use_dll_storage_attrs() {
256 llvm::SetDLLStorageClass(c, llvm::DLLImportStorageClass);
258 ccx.externs().borrow_mut().insert(name.to_string(), c);
262 fn require_alloc_fn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, info_ty: Ty<'tcx>, it: LangItem) -> DefId {
263 match bcx.tcx().lang_items.require(it) {
266 bcx.sess().fatal(&format!("allocation of `{}` {}", info_ty, s));
271 // The following malloc_raw_dyn* functions allocate a box to contain
272 // a given type, but with a potentially dynamic size.
274 pub fn malloc_raw_dyn<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
280 -> Result<'blk, 'tcx> {
281 let _icx = push_ctxt("malloc_raw_exchange");
284 let r = callee::trans_lang_call(bcx,
285 require_alloc_fn(bcx, info_ty, ExchangeMallocFnLangItem),
290 Result::new(r.bcx, PointerCast(r.bcx, r.val, llty_ptr))
294 pub fn bin_op_to_icmp_predicate(ccx: &CrateContext,
297 -> llvm::IntPredicate {
299 hir::BiEq => llvm::IntEQ,
300 hir::BiNe => llvm::IntNE,
301 hir::BiLt => if signed { llvm::IntSLT } else { llvm::IntULT },
302 hir::BiLe => if signed { llvm::IntSLE } else { llvm::IntULE },
303 hir::BiGt => if signed { llvm::IntSGT } else { llvm::IntUGT },
304 hir::BiGe => if signed { llvm::IntSGE } else { llvm::IntUGE },
307 .bug(&format!("comparison_op_to_icmp_predicate: expected comparison operator, \
314 pub fn bin_op_to_fcmp_predicate(ccx: &CrateContext, op: hir::BinOp_) -> llvm::RealPredicate {
316 hir::BiEq => llvm::RealOEQ,
317 hir::BiNe => llvm::RealUNE,
318 hir::BiLt => llvm::RealOLT,
319 hir::BiLe => llvm::RealOLE,
320 hir::BiGt => llvm::RealOGT,
321 hir::BiGe => llvm::RealOGE,
324 .bug(&format!("comparison_op_to_fcmp_predicate: expected comparison operator, \
331 pub fn compare_fat_ptrs<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
342 let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
343 let extra_eq = ICmp(bcx, llvm::IntEQ, lhs_extra, rhs_extra, debug_loc);
344 And(bcx, addr_eq, extra_eq, debug_loc)
347 let addr_eq = ICmp(bcx, llvm::IntNE, lhs_addr, rhs_addr, debug_loc);
348 let extra_eq = ICmp(bcx, llvm::IntNE, lhs_extra, rhs_extra, debug_loc);
349 Or(bcx, addr_eq, extra_eq, debug_loc)
351 hir::BiLe | hir::BiLt | hir::BiGe | hir::BiGt => {
352 // a OP b ~ a.0 STRICT(OP) b.0 | (a.0 == b.0 && a.1 OP a.1)
353 let (op, strict_op) = match op {
354 hir::BiLt => (llvm::IntULT, llvm::IntULT),
355 hir::BiLe => (llvm::IntULE, llvm::IntULT),
356 hir::BiGt => (llvm::IntUGT, llvm::IntUGT),
357 hir::BiGe => (llvm::IntUGE, llvm::IntUGT),
361 let addr_eq = ICmp(bcx, llvm::IntEQ, lhs_addr, rhs_addr, debug_loc);
362 let extra_op = ICmp(bcx, op, lhs_extra, rhs_extra, debug_loc);
363 let addr_eq_extra_op = And(bcx, addr_eq, extra_op, debug_loc);
365 let addr_strict = ICmp(bcx, strict_op, lhs_addr, rhs_addr, debug_loc);
366 Or(bcx, addr_strict, addr_eq_extra_op, debug_loc)
369 bcx.tcx().sess.bug("unexpected fat ptr binop");
374 pub fn compare_scalar_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
382 ty::TyTuple(ref tys) if tys.is_empty() => {
383 // We don't need to do actual comparisons for nil.
384 // () == () holds but () < () does not.
386 hir::BiEq | hir::BiLe | hir::BiGe => return C_bool(bcx.ccx(), true),
387 hir::BiNe | hir::BiLt | hir::BiGt => return C_bool(bcx.ccx(), false),
388 // refinements would be nice
389 _ => bcx.sess().bug("compare_scalar_types: must be a comparison operator"),
392 ty::TyBareFn(..) | ty::TyBool | ty::TyUint(_) | ty::TyChar => {
394 bin_op_to_icmp_predicate(bcx.ccx(), op, false),
399 ty::TyRawPtr(mt) if common::type_is_sized(bcx.tcx(), mt.ty) => {
401 bin_op_to_icmp_predicate(bcx.ccx(), op, false),
407 let lhs_addr = Load(bcx, GEPi(bcx, lhs, &[0, abi::FAT_PTR_ADDR]));
408 let lhs_extra = Load(bcx, GEPi(bcx, lhs, &[0, abi::FAT_PTR_EXTRA]));
410 let rhs_addr = Load(bcx, GEPi(bcx, rhs, &[0, abi::FAT_PTR_ADDR]));
411 let rhs_extra = Load(bcx, GEPi(bcx, rhs, &[0, abi::FAT_PTR_EXTRA]));
412 compare_fat_ptrs(bcx,
423 bin_op_to_icmp_predicate(bcx.ccx(), op, true),
430 bin_op_to_fcmp_predicate(bcx.ccx(), op),
435 // Should never get here, because t is scalar.
436 _ => bcx.sess().bug("non-scalar type passed to compare_scalar_types"),
440 pub fn compare_simd_types<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
448 let signed = match t.sty {
450 let cmp = bin_op_to_fcmp_predicate(bcx.ccx(), op);
451 return SExt(bcx, FCmp(bcx, cmp, lhs, rhs, debug_loc), ret_ty);
453 ty::TyUint(_) => false,
454 ty::TyInt(_) => true,
455 _ => bcx.sess().bug("compare_simd_types: invalid SIMD type"),
458 let cmp = bin_op_to_icmp_predicate(bcx.ccx(), op, signed);
459 // LLVM outputs an `< size x i1 >`, so we need to perform a sign extension
460 // to get the correctly sized type. This will compile to a single instruction
461 // once the IR is converted to assembly if the SIMD instruction is supported
462 // by the target architecture.
463 SExt(bcx, ICmp(bcx, cmp, lhs, rhs, debug_loc), ret_ty)
466 // Iterates through the elements of a structural type.
467 pub fn iter_structural_ty<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>,
472 where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>
474 let _icx = push_ctxt("iter_structural_ty");
476 fn iter_variant<'blk, 'tcx, F>(cx: Block<'blk, 'tcx>,
477 repr: &adt::Repr<'tcx>,
478 av: adt::MaybeSizedValue,
479 variant: ty::VariantDef<'tcx>,
480 substs: &Substs<'tcx>,
483 where F: FnMut(Block<'blk, 'tcx>, ValueRef, Ty<'tcx>) -> Block<'blk, 'tcx>
485 let _icx = push_ctxt("iter_variant");
489 for (i, field) in variant.fields.iter().enumerate() {
490 let arg = monomorphize::field_ty(tcx, substs, field);
492 adt::trans_field_ptr(cx, repr, av, variant.disr_val, i),
498 let value = if common::type_is_sized(cx.tcx(), t) {
499 adt::MaybeSizedValue::sized(av)
501 let data = Load(cx, expr::get_dataptr(cx, av));
502 let info = Load(cx, expr::get_meta(cx, av));
503 adt::MaybeSizedValue::unsized_(data, info)
508 ty::TyStruct(..) => {
509 let repr = adt::represent_type(cx.ccx(), t);
510 let VariantInfo { fields, discr } = VariantInfo::from_ty(cx.tcx(), t, None);
511 for (i, &Field(_, field_ty)) in fields.iter().enumerate() {
512 let llfld_a = adt::trans_field_ptr(cx, &*repr, value, discr, i);
514 let val = if common::type_is_sized(cx.tcx(), field_ty) {
517 let scratch = datum::rvalue_scratch_datum(cx, field_ty, "__fat_ptr_iter");
518 Store(cx, llfld_a, expr::get_dataptr(cx, scratch.val));
519 Store(cx, value.meta, expr::get_meta(cx, scratch.val));
522 cx = f(cx, val, field_ty);
525 ty::TyClosure(_, ref substs) => {
526 let repr = adt::represent_type(cx.ccx(), t);
527 for (i, upvar_ty) in substs.upvar_tys.iter().enumerate() {
528 let llupvar = adt::trans_field_ptr(cx, &*repr, value, 0, i);
529 cx = f(cx, llupvar, upvar_ty);
532 ty::TyArray(_, n) => {
533 let (base, len) = tvec::get_fixed_base_and_len(cx, value.value, n);
534 let unit_ty = t.sequence_element_type(cx.tcx());
535 cx = tvec::iter_vec_raw(cx, base, unit_ty, len, f);
537 ty::TySlice(_) | ty::TyStr => {
538 let unit_ty = t.sequence_element_type(cx.tcx());
539 cx = tvec::iter_vec_raw(cx, value.value, unit_ty, value.meta, f);
541 ty::TyTuple(ref args) => {
542 let repr = adt::represent_type(cx.ccx(), t);
543 for (i, arg) in args.iter().enumerate() {
544 let llfld_a = adt::trans_field_ptr(cx, &*repr, value, 0, i);
545 cx = f(cx, llfld_a, *arg);
548 ty::TyEnum(en, substs) => {
552 let repr = adt::represent_type(ccx, t);
553 let n_variants = en.variants.len();
555 // NB: we must hit the discriminant first so that structural
556 // comparison know not to proceed when the discriminants differ.
558 match adt::trans_switch(cx, &*repr, av) {
559 (_match::Single, None) => {
561 assert!(n_variants == 1);
562 cx = iter_variant(cx, &*repr, adt::MaybeSizedValue::sized(av),
563 &en.variants[0], substs, &mut f);
566 (_match::Switch, Some(lldiscrim_a)) => {
567 cx = f(cx, lldiscrim_a, cx.tcx().types.isize);
569 // Create a fall-through basic block for the "else" case of
570 // the switch instruction we're about to generate. Note that
571 // we do **not** use an Unreachable instruction here, even
572 // though most of the time this basic block will never be hit.
574 // When an enum is dropped it's contents are currently
575 // overwritten to DTOR_DONE, which means the discriminant
576 // could have changed value to something not within the actual
577 // range of the discriminant. Currently this function is only
578 // used for drop glue so in this case we just return quickly
579 // from the outer function, and any other use case will only
580 // call this for an already-valid enum in which case the `ret
581 // void` will never be hit.
582 let ret_void_cx = fcx.new_temp_block("enum-iter-ret-void");
583 RetVoid(ret_void_cx, DebugLoc::None);
584 let llswitch = Switch(cx, lldiscrim_a, ret_void_cx.llbb, n_variants);
585 let next_cx = fcx.new_temp_block("enum-iter-next");
587 for variant in &en.variants {
588 let variant_cx = fcx.new_temp_block(&format!("enum-iter-variant-{}",
591 let case_val = adt::trans_case(cx, &*repr, variant.disr_val);
592 AddCase(llswitch, case_val, variant_cx.llbb);
593 let variant_cx = iter_variant(variant_cx,
599 Br(variant_cx, next_cx.llbb, DebugLoc::None);
603 _ => ccx.sess().unimpl("value from adt::trans_switch in iter_structural_ty"),
607 cx.sess().unimpl(&format!("type in iter_structural_ty: {}", t))
614 /// Retrieve the information we are losing (making dynamic) in an unsizing
617 /// The `old_info` argument is a bit funny. It is intended for use
618 /// in an upcast, where the new vtable for an object will be drived
619 /// from the old one.
620 pub fn unsized_info<'ccx, 'tcx>(ccx: &CrateContext<'ccx, 'tcx>,
623 old_info: Option<ValueRef>,
624 param_substs: &'tcx Substs<'tcx>)
626 let (source, target) = ccx.tcx().struct_lockstep_tails(source, target);
627 match (&source.sty, &target.sty) {
628 (&ty::TyArray(_, len), &ty::TySlice(_)) => C_uint(ccx, len),
629 (&ty::TyTrait(_), &ty::TyTrait(_)) => {
630 // For now, upcasts are limited to changes in marker
631 // traits, and hence never actually require an actual
632 // change to the vtable.
633 old_info.expect("unsized_info: missing old info for trait upcast")
635 (_, &ty::TyTrait(box ty::TraitTy { ref principal, .. })) => {
636 // Note that we preserve binding levels here:
637 let substs = principal.0.substs.with_self_ty(source).erase_regions();
638 let substs = ccx.tcx().mk_substs(substs);
639 let trait_ref = ty::Binder(ty::TraitRef {
640 def_id: principal.def_id(),
643 consts::ptrcast(meth::get_vtable(ccx, trait_ref, param_substs),
644 Type::vtable_ptr(ccx))
646 _ => ccx.sess().bug(&format!("unsized_info: invalid unsizing {:?} -> {:?}",
652 /// Coerce `src` to `dst_ty`. `src_ty` must be a thin pointer.
653 pub fn unsize_thin_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
657 -> (ValueRef, ValueRef) {
658 debug!("unsize_thin_ptr: {:?} => {:?}", src_ty, dst_ty);
659 match (&src_ty.sty, &dst_ty.sty) {
660 (&ty::TyBox(a), &ty::TyBox(b)) |
661 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
662 &ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) |
663 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
664 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
665 (&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
666 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
667 assert!(common::type_is_sized(bcx.tcx(), a));
668 let ptr_ty = type_of::in_memory_type_of(bcx.ccx(), b).ptr_to();
669 (PointerCast(bcx, src, ptr_ty),
670 unsized_info(bcx.ccx(), a, b, None, bcx.fcx.param_substs))
672 _ => bcx.sess().bug("unsize_thin_ptr: called on bad types"),
676 /// Coerce `src`, which is a reference to a value of type `src_ty`,
677 /// to a value of type `dst_ty` and store the result in `dst`
678 pub fn coerce_unsized_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
683 match (&src_ty.sty, &dst_ty.sty) {
684 (&ty::TyBox(..), &ty::TyBox(..)) |
685 (&ty::TyRef(..), &ty::TyRef(..)) |
686 (&ty::TyRef(..), &ty::TyRawPtr(..)) |
687 (&ty::TyRawPtr(..), &ty::TyRawPtr(..)) => {
688 let (base, info) = if common::type_is_fat_ptr(bcx.tcx(), src_ty) {
689 // fat-ptr to fat-ptr unsize preserves the vtable
690 load_fat_ptr(bcx, src, src_ty)
692 let base = load_ty(bcx, src, src_ty);
693 unsize_thin_ptr(bcx, base, src_ty, dst_ty)
695 store_fat_ptr(bcx, base, info, dst, dst_ty);
698 // This can be extended to enums and tuples in the future.
699 // (&ty::TyEnum(def_id_a, _), &ty::TyEnum(def_id_b, _)) |
700 (&ty::TyStruct(def_a, _), &ty::TyStruct(def_b, _)) => {
701 assert_eq!(def_a, def_b);
703 let src_repr = adt::represent_type(bcx.ccx(), src_ty);
704 let src_fields = match &*src_repr {
705 &adt::Repr::Univariant(ref s, _) => &s.fields,
706 _ => bcx.sess().bug("struct has non-univariant repr"),
708 let dst_repr = adt::represent_type(bcx.ccx(), dst_ty);
709 let dst_fields = match &*dst_repr {
710 &adt::Repr::Univariant(ref s, _) => &s.fields,
711 _ => bcx.sess().bug("struct has non-univariant repr"),
714 let src = adt::MaybeSizedValue::sized(src);
715 let dst = adt::MaybeSizedValue::sized(dst);
717 let iter = src_fields.iter().zip(dst_fields).enumerate();
718 for (i, (src_fty, dst_fty)) in iter {
719 if type_is_zero_size(bcx.ccx(), dst_fty) {
723 let src_f = adt::trans_field_ptr(bcx, &src_repr, src, 0, i);
724 let dst_f = adt::trans_field_ptr(bcx, &dst_repr, dst, 0, i);
725 if src_fty == dst_fty {
726 memcpy_ty(bcx, dst_f, src_f, src_fty);
728 coerce_unsized_into(bcx, src_f, src_fty, dst_f, dst_fty);
732 _ => bcx.sess().bug(&format!("coerce_unsized_into: invalid coercion {:?} -> {:?}",
738 pub fn cast_shift_expr_rhs(cx: Block, op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef {
739 cast_shift_rhs(op, lhs, rhs, |a, b| Trunc(cx, a, b), |a, b| ZExt(cx, a, b))
742 pub fn cast_shift_const_rhs(op: hir::BinOp_, lhs: ValueRef, rhs: ValueRef) -> ValueRef {
746 |a, b| unsafe { llvm::LLVMConstTrunc(a, b.to_ref()) },
747 |a, b| unsafe { llvm::LLVMConstZExt(a, b.to_ref()) })
750 fn cast_shift_rhs<F, G>(op: hir::BinOp_,
756 where F: FnOnce(ValueRef, Type) -> ValueRef,
757 G: FnOnce(ValueRef, Type) -> ValueRef
759 // Shifts may have any size int on the rhs
760 if rustc_front::util::is_shift_binop(op) {
761 let mut rhs_llty = val_ty(rhs);
762 let mut lhs_llty = val_ty(lhs);
763 if rhs_llty.kind() == Vector {
764 rhs_llty = rhs_llty.element_type()
766 if lhs_llty.kind() == Vector {
767 lhs_llty = lhs_llty.element_type()
769 let rhs_sz = rhs_llty.int_width();
770 let lhs_sz = lhs_llty.int_width();
773 } else if lhs_sz > rhs_sz {
774 // FIXME (#1877: If shifting by negative
775 // values becomes not undefined then this is wrong.
785 pub fn llty_and_min_for_signed_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
790 let llty = Type::int_from_ty(cx.ccx(), t);
792 ast::TyIs if llty == Type::i32(cx.ccx()) => i32::MIN as u64,
793 ast::TyIs => i64::MIN as u64,
794 ast::TyI8 => i8::MIN as u64,
795 ast::TyI16 => i16::MIN as u64,
796 ast::TyI32 => i32::MIN as u64,
797 ast::TyI64 => i64::MIN as u64,
805 pub fn fail_if_zero_or_overflows<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
806 call_info: NodeIdAndSpan,
811 -> Block<'blk, 'tcx> {
812 let (zero_text, overflow_text) = if divrem.node == hir::BiDiv {
813 ("attempted to divide by zero",
814 "attempted to divide with overflow")
816 ("attempted remainder with a divisor of zero",
817 "attempted remainder with overflow")
819 let debug_loc = call_info.debug_loc();
821 let (is_zero, is_signed) = match rhs_t.sty {
823 let zero = C_integral(Type::int_from_ty(cx.ccx(), t), 0, false);
824 (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), true)
827 let zero = C_integral(Type::uint_from_ty(cx.ccx(), t), 0, false);
828 (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), false)
830 ty::TyStruct(def, _) if def.is_simd() => {
831 let mut res = C_bool(cx.ccx(), false);
832 for i in 0..rhs_t.simd_size(cx.tcx()) {
835 IsNull(cx, ExtractElement(cx, rhs, C_int(cx.ccx(), i as i64))),
841 cx.sess().bug(&format!("fail-if-zero on unexpected type: {}", rhs_t));
844 let bcx = with_cond(cx, is_zero, |bcx| {
845 controlflow::trans_fail(bcx, call_info, InternedString::new(zero_text))
848 // To quote LLVM's documentation for the sdiv instruction:
850 // Division by zero leads to undefined behavior. Overflow also leads
851 // to undefined behavior; this is a rare case, but can occur, for
852 // example, by doing a 32-bit division of -2147483648 by -1.
854 // In order to avoid undefined behavior, we perform runtime checks for
855 // signed division/remainder which would trigger overflow. For unsigned
856 // integers, no action beyond checking for zero need be taken.
858 let (llty, min) = llty_and_min_for_signed_ty(cx, rhs_t);
859 let minus_one = ICmp(bcx,
862 C_integral(llty, !0, false),
864 with_cond(bcx, minus_one, |bcx| {
865 let is_min = ICmp(bcx,
868 C_integral(llty, min, true),
870 with_cond(bcx, is_min, |bcx| {
871 controlflow::trans_fail(bcx, call_info, InternedString::new(overflow_text))
879 pub fn trans_external_path<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
883 let name = ccx.sess().cstore.item_symbol(did);
885 ty::TyBareFn(_, ref fn_ty) => {
886 match ccx.sess().target.target.adjust_abi(fn_ty.abi) {
888 get_extern_rust_fn(ccx, t, &name[..], did)
890 RustIntrinsic | PlatformIntrinsic => {
891 ccx.sess().bug("unexpected intrinsic in trans_external_path")
894 let attrs = ccx.sess().cstore.item_attrs(did);
895 foreign::register_foreign_item_fn(ccx, fn_ty.abi, t, &name, &attrs)
900 get_extern_const(ccx, did, t)
905 pub fn invoke<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
910 -> (ValueRef, Block<'blk, 'tcx>) {
911 let _icx = push_ctxt("invoke_");
912 if bcx.unreachable.get() {
913 return (C_null(Type::i8(bcx.ccx())), bcx);
916 let attributes = attributes::from_fn_type(bcx.ccx(), fn_ty);
918 match bcx.opt_node_id {
920 debug!("invoke at ???");
923 debug!("invoke at {}", bcx.tcx().map.node_to_string(id));
927 if need_invoke(bcx) {
928 debug!("invoking {} at {:?}", bcx.val_to_string(llfn), bcx.llbb);
929 for &llarg in llargs {
930 debug!("arg: {}", bcx.val_to_string(llarg));
932 let normal_bcx = bcx.fcx.new_temp_block("normal-return");
933 let landing_pad = bcx.fcx.get_landing_pad();
935 let llresult = Invoke(bcx,
942 return (llresult, normal_bcx);
944 debug!("calling {} at {:?}", bcx.val_to_string(llfn), bcx.llbb);
945 for &llarg in llargs {
946 debug!("arg: {}", bcx.val_to_string(llarg));
949 let llresult = Call(bcx, llfn, &llargs[..], Some(attributes), debug_loc);
950 return (llresult, bcx);
954 /// Returns whether this session's target will use SEH-based unwinding.
956 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
957 /// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
958 /// 64-bit MinGW) instead of "full SEH".
959 pub fn wants_msvc_seh(sess: &Session) -> bool {
960 sess.target.target.options.is_like_msvc && sess.target.target.arch == "x86"
963 pub fn avoid_invoke(bcx: Block) -> bool {
964 // FIXME(#25869) currently SEH-based unwinding is pretty buggy in LLVM and
965 // is being overhauled as this is being written. Until that
966 // time such that upstream LLVM's implementation is more solid
967 // and we start binding it we need to skip invokes for any
968 // target which wants SEH-based unwinding.
969 if bcx.sess().no_landing_pads() || wants_msvc_seh(bcx.sess()) {
971 } else if bcx.is_lpad {
972 // Avoid using invoke if we are already inside a landing pad.
979 pub fn need_invoke(bcx: Block) -> bool {
980 if avoid_invoke(bcx) {
983 bcx.fcx.needs_invoke()
987 pub fn load_if_immediate<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, t: Ty<'tcx>) -> ValueRef {
988 let _icx = push_ctxt("load_if_immediate");
989 if type_is_immediate(cx.ccx(), t) {
990 return load_ty(cx, v, t);
995 /// Helper for loading values from memory. Does the necessary conversion if the in-memory type
996 /// differs from the type used for SSA values. Also handles various special cases where the type
997 /// gives us better information about what we are loading.
998 pub fn load_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ptr: ValueRef, t: Ty<'tcx>) -> ValueRef {
999 if cx.unreachable.get() || type_is_zero_size(cx.ccx(), t) {
1000 return C_undef(type_of::type_of(cx.ccx(), t));
1003 let ptr = to_arg_ty_ptr(cx, ptr, t);
1004 let align = type_of::align_of(cx.ccx(), t);
1006 if type_is_immediate(cx.ccx(), t) && type_of::type_of(cx.ccx(), t).is_aggregate() {
1007 let load = Load(cx, ptr);
1009 llvm::LLVMSetAlignment(load, align);
1015 let global = llvm::LLVMIsAGlobalVariable(ptr);
1016 if !global.is_null() && llvm::LLVMIsGlobalConstant(global) == llvm::True {
1017 let val = llvm::LLVMGetInitializer(global);
1019 return to_arg_ty(cx, val, t);
1024 let val = if t.is_bool() {
1025 LoadRangeAssert(cx, ptr, 0, 2, llvm::False)
1026 } else if t.is_char() {
1027 // a char is a Unicode codepoint, and so takes values from 0
1028 // to 0x10FFFF inclusive only.
1029 LoadRangeAssert(cx, ptr, 0, 0x10FFFF + 1, llvm::False)
1030 } else if (t.is_region_ptr() || t.is_unique()) && !common::type_is_fat_ptr(cx.tcx(), t) {
1031 LoadNonNull(cx, ptr)
1037 llvm::LLVMSetAlignment(val, align);
1040 to_arg_ty(cx, val, t)
1043 /// Helper for storing values in memory. Does the necessary conversion if the in-memory type
1044 /// differs from the type used for SSA values.
1045 pub fn store_ty<'blk, 'tcx>(cx: Block<'blk, 'tcx>, v: ValueRef, dst: ValueRef, t: Ty<'tcx>) {
1046 if cx.unreachable.get() {
1050 debug!("store_ty: {} : {:?} <- {}",
1051 cx.val_to_string(dst),
1053 cx.val_to_string(v));
1055 if common::type_is_fat_ptr(cx.tcx(), t) {
1057 ExtractValue(cx, v, abi::FAT_PTR_ADDR),
1058 expr::get_dataptr(cx, dst));
1060 ExtractValue(cx, v, abi::FAT_PTR_EXTRA),
1061 expr::get_meta(cx, dst));
1063 let store = Store(cx, from_arg_ty(cx, v, t), to_arg_ty_ptr(cx, dst, t));
1065 llvm::LLVMSetAlignment(store, type_of::align_of(cx.ccx(), t));
1070 pub fn store_fat_ptr<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
1075 // FIXME: emit metadata
1076 Store(cx, data, expr::get_dataptr(cx, dst));
1077 Store(cx, extra, expr::get_meta(cx, dst));
1080 pub fn load_fat_ptr<'blk, 'tcx>(cx: Block<'blk, 'tcx>,
1083 -> (ValueRef, ValueRef) {
1084 // FIXME: emit metadata
1085 (Load(cx, expr::get_dataptr(cx, src)),
1086 Load(cx, expr::get_meta(cx, src)))
1089 pub fn from_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef {
1091 ZExt(bcx, val, Type::i8(bcx.ccx()))
1097 pub fn to_arg_ty(bcx: Block, val: ValueRef, ty: Ty) -> ValueRef {
1099 Trunc(bcx, val, Type::i1(bcx.ccx()))
1105 pub fn to_arg_ty_ptr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ptr: ValueRef, ty: Ty<'tcx>) -> ValueRef {
1106 if type_is_immediate(bcx.ccx(), ty) && type_of::type_of(bcx.ccx(), ty).is_aggregate() {
1107 // We want to pass small aggregates as immediate values, but using an aggregate LLVM type
1108 // for this leads to bad optimizations, so its arg type is an appropriately sized integer
1109 // and we have to convert it
1110 BitCast(bcx, ptr, type_of::arg_type_of(bcx.ccx(), ty).ptr_to())
1116 pub fn init_local<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, local: &hir::Local) -> Block<'blk, 'tcx> {
1117 debug!("init_local(bcx={}, local.id={})", bcx.to_str(), local.id);
1118 let _indenter = indenter();
1119 let _icx = push_ctxt("init_local");
1120 _match::store_local(bcx, local)
1123 pub fn raw_block<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>,
1125 llbb: BasicBlockRef)
1126 -> Block<'blk, 'tcx> {
1127 common::BlockS::new(llbb, is_lpad, None, fcx)
1130 pub fn with_cond<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>, val: ValueRef, f: F) -> Block<'blk, 'tcx>
1131 where F: FnOnce(Block<'blk, 'tcx>) -> Block<'blk, 'tcx>
1133 let _icx = push_ctxt("with_cond");
1135 if bcx.unreachable.get() || common::const_to_opt_uint(val) == Some(0) {
1140 let next_cx = fcx.new_temp_block("next");
1141 let cond_cx = fcx.new_temp_block("cond");
1142 CondBr(bcx, val, cond_cx.llbb, next_cx.llbb, DebugLoc::None);
1143 let after_cx = f(cond_cx);
1144 if !after_cx.terminated.get() {
1145 Br(after_cx, next_cx.llbb, DebugLoc::None);
1150 enum Lifetime { Start, End }
1152 // If LLVM lifetime intrinsic support is enabled (i.e. optimizations
1153 // on), and `ptr` is nonzero-sized, then extracts the size of `ptr`
1154 // and the intrinsic for `lt` and passes them to `emit`, which is in
1155 // charge of generating code to call the passed intrinsic on whatever
1156 // block of generated code is targetted for the intrinsic.
1158 // If LLVM lifetime intrinsic support is disabled (i.e. optimizations
1159 // off) or `ptr` is zero-sized, then no-op (does not call `emit`).
1160 fn core_lifetime_emit<'blk, 'tcx, F>(ccx: &'blk CrateContext<'blk, 'tcx>,
1164 where F: FnOnce(&'blk CrateContext<'blk, 'tcx>, machine::llsize, ValueRef)
1166 if ccx.sess().opts.optimize == config::No {
1170 let _icx = push_ctxt(match lt {
1171 Lifetime::Start => "lifetime_start",
1172 Lifetime::End => "lifetime_end"
1175 let size = machine::llsize_of_alloc(ccx, val_ty(ptr).element_type());
1180 let lifetime_intrinsic = ccx.get_intrinsic(match lt {
1181 Lifetime::Start => "llvm.lifetime.start",
1182 Lifetime::End => "llvm.lifetime.end"
1184 emit(ccx, size, lifetime_intrinsic)
1187 pub fn call_lifetime_start(cx: Block, ptr: ValueRef) {
1188 core_lifetime_emit(cx.ccx(), ptr, Lifetime::Start, |ccx, size, lifetime_start| {
1189 let ptr = PointerCast(cx, ptr, Type::i8p(ccx));
1192 &[C_u64(ccx, size), ptr],
1198 pub fn call_lifetime_end(cx: Block, ptr: ValueRef) {
1199 core_lifetime_emit(cx.ccx(), ptr, Lifetime::End, |ccx, size, lifetime_end| {
1200 let ptr = PointerCast(cx, ptr, Type::i8p(ccx));
1203 &[C_u64(ccx, size), ptr],
1209 // Generates code for resumption of unwind at the end of a landing pad.
1210 pub fn trans_unwind_resume(bcx: Block, lpval: ValueRef) {
1211 if !bcx.sess().target.target.options.custom_unwind_resume {
1214 let exc_ptr = ExtractValue(bcx, lpval, 0);
1215 let llunwresume = bcx.fcx.eh_unwind_resume();
1216 Call(bcx, llunwresume, &[exc_ptr], None, DebugLoc::None);
1222 pub fn call_memcpy(cx: Block, dst: ValueRef, src: ValueRef, n_bytes: ValueRef, align: u32) {
1223 let _icx = push_ctxt("call_memcpy");
1225 let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
1226 let key = format!("llvm.memcpy.p0i8.p0i8.i{}", ptr_width);
1227 let memcpy = ccx.get_intrinsic(&key);
1228 let src_ptr = PointerCast(cx, src, Type::i8p(ccx));
1229 let dst_ptr = PointerCast(cx, dst, Type::i8p(ccx));
1230 let size = IntCast(cx, n_bytes, ccx.int_type());
1231 let align = C_i32(ccx, align as i32);
1232 let volatile = C_bool(ccx, false);
1235 &[dst_ptr, src_ptr, size, align, volatile],
1240 pub fn memcpy_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, dst: ValueRef, src: ValueRef, t: Ty<'tcx>) {
1241 let _icx = push_ctxt("memcpy_ty");
1242 let ccx = bcx.ccx();
1244 if type_is_zero_size(ccx, t) {
1248 if t.is_structural() {
1249 let llty = type_of::type_of(ccx, t);
1250 let llsz = llsize_of(ccx, llty);
1251 let llalign = type_of::align_of(ccx, t);
1252 call_memcpy(bcx, dst, src, llsz, llalign as u32);
1253 } else if common::type_is_fat_ptr(bcx.tcx(), t) {
1254 let (data, extra) = load_fat_ptr(bcx, src, t);
1255 store_fat_ptr(bcx, data, extra, dst, t);
1257 store_ty(bcx, load_ty(bcx, src, t), dst, t);
1261 pub fn drop_done_fill_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) {
1262 if cx.unreachable.get() {
1265 let _icx = push_ctxt("drop_done_fill_mem");
1267 memfill(&B(bcx), llptr, t, adt::DTOR_DONE);
1270 pub fn init_zero_mem<'blk, 'tcx>(cx: Block<'blk, 'tcx>, llptr: ValueRef, t: Ty<'tcx>) {
1271 if cx.unreachable.get() {
1274 let _icx = push_ctxt("init_zero_mem");
1276 memfill(&B(bcx), llptr, t, 0);
1279 // Always use this function instead of storing a constant byte to the memory
1280 // in question. e.g. if you store a zero constant, LLVM will drown in vreg
1281 // allocation for large data structures, and the generated code will be
1282 // awful. (A telltale sign of this is large quantities of
1283 // `mov [byte ptr foo],0` in the generated code.)
1284 fn memfill<'a, 'tcx>(b: &Builder<'a, 'tcx>, llptr: ValueRef, ty: Ty<'tcx>, byte: u8) {
1285 let _icx = push_ctxt("memfill");
1288 let llty = type_of::type_of(ccx, ty);
1289 let ptr_width = &ccx.sess().target.target.target_pointer_width[..];
1290 let intrinsic_key = format!("llvm.memset.p0i8.i{}", ptr_width);
1292 let llintrinsicfn = ccx.get_intrinsic(&intrinsic_key);
1293 let llptr = b.pointercast(llptr, Type::i8(ccx).ptr_to());
1294 let llzeroval = C_u8(ccx, byte);
1295 let size = machine::llsize_of(ccx, llty);
1296 let align = C_i32(ccx, type_of::align_of(ccx, ty) as i32);
1297 let volatile = C_bool(ccx, false);
1298 b.call(llintrinsicfn,
1299 &[llptr, llzeroval, size, align, volatile],
1303 /// In general, when we create an scratch value in an alloca, the
1304 /// creator may not know if the block (that initializes the scratch
1305 /// with the desired value) actually dominates the cleanup associated
1306 /// with the scratch value.
1308 /// To deal with this, when we do an alloca (at the *start* of whole
1309 /// function body), we optionally can also set the associated
1310 /// dropped-flag state of the alloca to "dropped."
1311 #[derive(Copy, Clone, Debug)]
1312 pub enum InitAlloca {
1313 /// Indicates that the state should have its associated drop flag
1314 /// set to "dropped" at the point of allocation.
1316 /// Indicates the value of the associated drop flag is irrelevant.
1317 /// The embedded string literal is a programmer provided argument
1318 /// for why. This is a safeguard forcing compiler devs to
1319 /// document; it might be a good idea to also emit this as a
1320 /// comment with the alloca itself when emitting LLVM output.ll.
1321 Uninit(&'static str),
1325 pub fn alloc_ty<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1327 name: &str) -> ValueRef {
1328 // pnkfelix: I do not know why alloc_ty meets the assumptions for
1329 // passing Uninit, but it was never needed (even back when we had
1330 // the original boolean `zero` flag on `lvalue_scratch_datum`).
1331 alloc_ty_init(bcx, t, InitAlloca::Uninit("all alloc_ty are uninit"), name)
1334 /// This variant of `fn alloc_ty` does not necessarily assume that the
1335 /// alloca should be created with no initial value. Instead the caller
1336 /// controls that assumption via the `init` flag.
1338 /// Note that if the alloca *is* initialized via `init`, then we will
1339 /// also inject an `llvm.lifetime.start` before that initialization
1340 /// occurs, and thus callers should not call_lifetime_start
1341 /// themselves. But if `init` says "uninitialized", then callers are
1342 /// in charge of choosing where to call_lifetime_start and
1343 /// subsequently populate the alloca.
1345 /// (See related discussion on PR #30823.)
1346 pub fn alloc_ty_init<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1349 name: &str) -> ValueRef {
1350 let _icx = push_ctxt("alloc_ty");
1351 let ccx = bcx.ccx();
1352 let ty = type_of::type_of(ccx, t);
1353 assert!(!t.has_param_types());
1355 InitAlloca::Dropped => alloca_dropped(bcx, t, name),
1356 InitAlloca::Uninit(_) => alloca(bcx, ty, name),
1360 pub fn alloca_dropped<'blk, 'tcx>(cx: Block<'blk, 'tcx>, ty: Ty<'tcx>, name: &str) -> ValueRef {
1361 let _icx = push_ctxt("alloca_dropped");
1362 let llty = type_of::type_of(cx.ccx(), ty);
1363 if cx.unreachable.get() {
1364 unsafe { return llvm::LLVMGetUndef(llty.ptr_to().to_ref()); }
1366 let p = alloca(cx, llty, name);
1367 let b = cx.fcx.ccx.builder();
1368 b.position_before(cx.fcx.alloca_insert_pt.get().unwrap());
1370 // This is just like `call_lifetime_start` (but latter expects a
1371 // Block, which we do not have for `alloca_insert_pt`).
1372 core_lifetime_emit(cx.ccx(), p, Lifetime::Start, |ccx, size, lifetime_start| {
1373 let ptr = b.pointercast(p, Type::i8p(ccx));
1374 b.call(lifetime_start, &[C_u64(ccx, size), ptr], None);
1376 memfill(&b, p, ty, adt::DTOR_DONE);
1380 pub fn alloca(cx: Block, ty: Type, name: &str) -> ValueRef {
1381 let _icx = push_ctxt("alloca");
1382 if cx.unreachable.get() {
1384 return llvm::LLVMGetUndef(ty.ptr_to().to_ref());
1387 debuginfo::clear_source_location(cx.fcx);
1388 Alloca(cx, ty, name)
1391 pub fn set_value_name(val: ValueRef, name: &str) {
1393 let name = CString::new(name).unwrap();
1394 llvm::LLVMSetValueName(val, name.as_ptr());
1398 // Creates the alloca slot which holds the pointer to the slot for the final return value
1399 pub fn make_return_slot_pointer<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
1400 output_type: Ty<'tcx>)
1402 let lloutputtype = type_of::type_of(fcx.ccx, output_type);
1404 // We create an alloca to hold a pointer of type `output_type`
1405 // which will hold the pointer to the right alloca which has the
1407 if fcx.needs_ret_allocas {
1408 // Let's create the stack slot
1409 let slot = AllocaFcx(fcx, lloutputtype.ptr_to(), "llretslotptr");
1411 // and if we're using an out pointer, then store that in our newly made slot
1412 if type_of::return_uses_outptr(fcx.ccx, output_type) {
1413 let outptr = get_param(fcx.llfn, 0);
1415 let b = fcx.ccx.builder();
1416 b.position_before(fcx.alloca_insert_pt.get().unwrap());
1417 b.store(outptr, slot);
1422 // But if there are no nested returns, we skip the indirection and have a single
1425 if type_of::return_uses_outptr(fcx.ccx, output_type) {
1426 get_param(fcx.llfn, 0)
1428 AllocaFcx(fcx, lloutputtype, "sret_slot")
1433 struct FindNestedReturn {
1437 impl FindNestedReturn {
1438 fn new() -> FindNestedReturn {
1445 impl<'v> Visitor<'v> for FindNestedReturn {
1446 fn visit_expr(&mut self, e: &hir::Expr) {
1448 hir::ExprRet(..) => {
1451 _ => intravisit::walk_expr(self, e),
1456 fn build_cfg(tcx: &ty::ctxt, id: ast::NodeId) -> (ast::NodeId, Option<cfg::CFG>) {
1457 let blk = match tcx.map.find(id) {
1458 Some(hir_map::NodeItem(i)) => {
1460 hir::ItemFn(_, _, _, _, _, ref blk) => {
1463 _ => tcx.sess.bug("unexpected item variant in has_nested_returns"),
1466 Some(hir_map::NodeTraitItem(trait_item)) => {
1467 match trait_item.node {
1468 hir::MethodTraitItem(_, Some(ref body)) => body,
1470 tcx.sess.bug("unexpected variant: trait item other than a provided method in \
1471 has_nested_returns")
1475 Some(hir_map::NodeImplItem(impl_item)) => {
1476 match impl_item.node {
1477 hir::ImplItemKind::Method(_, ref body) => body,
1479 tcx.sess.bug("unexpected variant: non-method impl item in has_nested_returns")
1483 Some(hir_map::NodeExpr(e)) => {
1485 hir::ExprClosure(_, _, ref blk) => blk,
1486 _ => tcx.sess.bug("unexpected expr variant in has_nested_returns"),
1489 Some(hir_map::NodeVariant(..)) |
1490 Some(hir_map::NodeStructCtor(..)) => return (ast::DUMMY_NODE_ID, None),
1493 None if id == ast::DUMMY_NODE_ID => return (ast::DUMMY_NODE_ID, None),
1495 _ => tcx.sess.bug(&format!("unexpected variant in has_nested_returns: {}",
1496 tcx.map.path_to_string(id))),
1499 (blk.id, Some(cfg::CFG::new(tcx, blk)))
1502 // Checks for the presence of "nested returns" in a function.
1503 // Nested returns are when the inner expression of a return expression
1504 // (the 'expr' in 'return expr') contains a return expression. Only cases
1505 // where the outer return is actually reachable are considered. Implicit
1506 // returns from the end of blocks are considered as well.
1508 // This check is needed to handle the case where the inner expression is
1509 // part of a larger expression that may have already partially-filled the
1510 // return slot alloca. This can cause errors related to clean-up due to
1511 // the clobbering of the existing value in the return slot.
1512 fn has_nested_returns(tcx: &ty::ctxt, cfg: &cfg::CFG, blk_id: ast::NodeId) -> bool {
1513 for index in cfg.graph.depth_traverse(cfg.entry) {
1514 let n = cfg.graph.node_data(index);
1515 match tcx.map.find(n.id()) {
1516 Some(hir_map::NodeExpr(ex)) => {
1517 if let hir::ExprRet(Some(ref ret_expr)) = ex.node {
1518 let mut visitor = FindNestedReturn::new();
1519 intravisit::walk_expr(&mut visitor, &**ret_expr);
1525 Some(hir_map::NodeBlock(blk)) if blk.id == blk_id => {
1526 let mut visitor = FindNestedReturn::new();
1527 walk_list!(&mut visitor, visit_expr, &blk.expr);
1539 // NB: must keep 4 fns in sync:
1542 // - create_datums_for_fn_args.
1546 // Be warned! You must call `init_function` before doing anything with the
1547 // returned function context.
1548 pub fn new_fn_ctxt<'a, 'tcx>(ccx: &'a CrateContext<'a, 'tcx>,
1552 output_type: ty::FnOutput<'tcx>,
1553 param_substs: &'tcx Substs<'tcx>,
1555 block_arena: &'a TypedArena<common::BlockS<'a, 'tcx>>)
1556 -> FunctionContext<'a, 'tcx> {
1557 common::validate_substs(param_substs);
1559 debug!("new_fn_ctxt(path={}, id={}, param_substs={:?})",
1563 ccx.tcx().map.path_to_string(id).to_string()
1568 let uses_outptr = match output_type {
1569 ty::FnConverging(output_type) => {
1570 let substd_output_type = monomorphize::apply_param_substs(ccx.tcx(),
1573 type_of::return_uses_outptr(ccx, substd_output_type)
1575 ty::FnDiverging => false,
1577 let debug_context = debuginfo::create_function_debug_context(ccx, id, param_substs, llfndecl);
1578 let (blk_id, cfg) = build_cfg(ccx.tcx(), id);
1579 let nested_returns = if let Some(ref cfg) = cfg {
1580 has_nested_returns(ccx.tcx(), cfg, blk_id)
1585 let mir = ccx.mir_map().get(&id);
1587 let mut fcx = FunctionContext {
1591 llretslotptr: Cell::new(None),
1592 param_env: ccx.tcx().empty_parameter_environment(),
1593 alloca_insert_pt: Cell::new(None),
1594 llreturn: Cell::new(None),
1595 needs_ret_allocas: nested_returns,
1596 personality: Cell::new(None),
1597 caller_expects_out_pointer: uses_outptr,
1598 lllocals: RefCell::new(NodeMap()),
1599 llupvars: RefCell::new(NodeMap()),
1600 lldropflag_hints: RefCell::new(DropFlagHintsMap::new()),
1602 param_substs: param_substs,
1604 block_arena: block_arena,
1606 debug_context: debug_context,
1607 scopes: RefCell::new(Vec::new()),
1612 fcx.llenv = Some(get_param(fcx.llfn, fcx.env_arg_pos() as c_uint))
1618 /// Performs setup on a newly created function, creating the entry scope block
1619 /// and allocating space for the return pointer.
1620 pub fn init_function<'a, 'tcx>(fcx: &'a FunctionContext<'a, 'tcx>,
1622 output: ty::FnOutput<'tcx>)
1623 -> Block<'a, 'tcx> {
1624 let entry_bcx = fcx.new_temp_block("entry-block");
1626 // Use a dummy instruction as the insertion point for all allocas.
1627 // This is later removed in FunctionContext::cleanup.
1628 fcx.alloca_insert_pt.set(Some(unsafe {
1629 Load(entry_bcx, C_null(Type::i8p(fcx.ccx)));
1630 llvm::LLVMGetFirstInstruction(entry_bcx.llbb)
1633 if let ty::FnConverging(output_type) = output {
1634 // This shouldn't need to recompute the return type,
1635 // as new_fn_ctxt did it already.
1636 let substd_output_type = fcx.monomorphize(&output_type);
1637 if !return_type_is_void(fcx.ccx, substd_output_type) {
1638 // If the function returns nil/bot, there is no real return
1639 // value, so do not set `llretslotptr`.
1640 if !skip_retptr || fcx.caller_expects_out_pointer {
1641 // Otherwise, we normally allocate the llretslotptr, unless we
1642 // have been instructed to skip it for immediate return
1644 fcx.llretslotptr.set(Some(make_return_slot_pointer(fcx, substd_output_type)));
1649 // Create the drop-flag hints for every unfragmented path in the function.
1650 let tcx = fcx.ccx.tcx();
1651 let fn_did = tcx.map.local_def_id(fcx.id);
1652 let tables = tcx.tables.borrow();
1653 let mut hints = fcx.lldropflag_hints.borrow_mut();
1654 let fragment_infos = tcx.fragment_infos.borrow();
1656 // Intern table for drop-flag hint datums.
1657 let mut seen = HashMap::new();
1659 if let Some(fragment_infos) = fragment_infos.get(&fn_did) {
1660 for &info in fragment_infos {
1662 let make_datum = |id| {
1663 let init_val = C_u8(fcx.ccx, adt::DTOR_NEEDED_HINT);
1664 let llname = &format!("dropflag_hint_{}", id);
1665 debug!("adding hint {}", llname);
1666 let ty = tcx.types.u8;
1667 let ptr = alloc_ty(entry_bcx, ty, llname);
1668 Store(entry_bcx, init_val, ptr);
1669 let flag = datum::Lvalue::new_dropflag_hint("base::init_function");
1670 datum::Datum::new(ptr, ty, flag)
1673 let (var, datum) = match info {
1674 ty::FragmentInfo::Moved { var, .. } |
1675 ty::FragmentInfo::Assigned { var, .. } => {
1676 let opt_datum = seen.get(&var).cloned().unwrap_or_else(|| {
1677 let ty = tables.node_types[&var];
1678 if fcx.type_needs_drop(ty) {
1679 let datum = make_datum(var);
1680 seen.insert(var, Some(datum.clone()));
1683 // No drop call needed, so we don't need a dropflag hint
1687 if let Some(datum) = opt_datum {
1695 ty::FragmentInfo::Moved { move_expr: expr_id, .. } => {
1696 debug!("FragmentInfo::Moved insert drop hint for {}", expr_id);
1697 hints.insert(expr_id, DropHint::new(var, datum));
1699 ty::FragmentInfo::Assigned { assignee_id: expr_id, .. } => {
1700 debug!("FragmentInfo::Assigned insert drop hint for {}", expr_id);
1701 hints.insert(expr_id, DropHint::new(var, datum));
1710 // NB: must keep 4 fns in sync:
1713 // - create_datums_for_fn_args.
1717 pub fn arg_kind<'a, 'tcx>(cx: &FunctionContext<'a, 'tcx>, t: Ty<'tcx>) -> datum::Rvalue {
1718 use trans::datum::{ByRef, ByValue};
1721 mode: if arg_is_indirect(cx.ccx, t) { ByRef } else { ByValue }
1725 // create_datums_for_fn_args: creates lvalue datums for each of the
1726 // incoming function arguments.
1727 pub fn create_datums_for_fn_args<'a, 'tcx>(mut bcx: Block<'a, 'tcx>,
1729 arg_tys: &[Ty<'tcx>],
1730 has_tupled_arg: bool,
1731 arg_scope: cleanup::CustomScopeIndex)
1732 -> Block<'a, 'tcx> {
1733 let _icx = push_ctxt("create_datums_for_fn_args");
1735 let arg_scope_id = cleanup::CustomScope(arg_scope);
1737 debug!("create_datums_for_fn_args");
1739 // Return an array wrapping the ValueRefs that we get from `get_param` for
1740 // each argument into datums.
1742 // For certain mode/type combinations, the raw llarg values are passed
1743 // by value. However, within the fn body itself, we want to always
1744 // have all locals and arguments be by-ref so that we can cancel the
1745 // cleanup and for better interaction with LLVM's debug info. So, if
1746 // the argument would be passed by value, we store it into an alloca.
1747 // This alloca should be optimized away by LLVM's mem-to-reg pass in
1748 // the event it's not truly needed.
1749 let mut idx = fcx.arg_offset() as c_uint;
1750 let uninit_reason = InitAlloca::Uninit("fn_arg populate dominates dtor");
1751 for (i, &arg_ty) in arg_tys.iter().enumerate() {
1752 let arg_datum = if !has_tupled_arg || i < arg_tys.len() - 1 {
1753 if type_of::arg_is_indirect(bcx.ccx(), arg_ty) &&
1754 bcx.sess().opts.debuginfo != FullDebugInfo {
1755 // Don't copy an indirect argument to an alloca, the caller
1756 // already put it in a temporary alloca and gave it up, unless
1757 // we emit extra-debug-info, which requires local allocas :(.
1758 let llarg = get_param(fcx.llfn, idx);
1760 bcx.fcx.schedule_lifetime_end(arg_scope_id, llarg);
1761 bcx.fcx.schedule_drop_mem(arg_scope_id, llarg, arg_ty, None);
1763 datum::Datum::new(llarg,
1765 datum::Lvalue::new("create_datum_for_fn_args"))
1766 } else if common::type_is_fat_ptr(bcx.tcx(), arg_ty) {
1767 let data = get_param(fcx.llfn, idx);
1768 let extra = get_param(fcx.llfn, idx + 1);
1770 unpack_datum!(bcx, datum::lvalue_scratch_datum(bcx, arg_ty, "", uninit_reason,
1771 arg_scope_id, (data, extra),
1772 |(data, extra), bcx, dst| {
1773 debug!("populate call for create_datum_for_fn_args \
1774 early fat arg, on arg[{}] ty={:?}", i, arg_ty);
1776 Store(bcx, data, expr::get_dataptr(bcx, dst));
1777 Store(bcx, extra, expr::get_meta(bcx, dst));
1781 let llarg = get_param(fcx.llfn, idx);
1783 let tmp = datum::Datum::new(llarg, arg_ty, arg_kind(fcx, arg_ty));
1785 datum::lvalue_scratch_datum(bcx,
1793 debug!("populate call for create_datum_for_fn_args \
1794 early thin arg, on arg[{}] ty={:?}", i, arg_ty);
1796 tmp.store_to(bcx, dst)
1800 // FIXME(pcwalton): Reduce the amount of code bloat this is responsible for.
1802 ty::TyTuple(ref tupled_arg_tys) => {
1804 datum::lvalue_scratch_datum(bcx,
1813 debug!("populate call for create_datum_for_fn_args \
1814 tupled_args, on arg[{}] ty={:?}", i, arg_ty);
1815 for (j, &tupled_arg_ty) in
1816 tupled_arg_tys.iter().enumerate() {
1817 let lldest = StructGEP(bcx, llval, j);
1818 if common::type_is_fat_ptr(bcx.tcx(), tupled_arg_ty) {
1819 let data = get_param(bcx.fcx.llfn, idx);
1820 let extra = get_param(bcx.fcx.llfn, idx + 1);
1821 Store(bcx, data, expr::get_dataptr(bcx, lldest));
1822 Store(bcx, extra, expr::get_meta(bcx, lldest));
1825 let datum = datum::Datum::new(
1826 get_param(bcx.fcx.llfn, idx),
1828 arg_kind(bcx.fcx, tupled_arg_ty));
1830 bcx = datum.store_to(bcx, lldest);
1839 .bug("last argument of a function with `rust-call` ABI isn't a tuple?!")
1844 let pat = &*args[i].pat;
1845 bcx = if let Some(name) = simple_name(pat) {
1846 // Generate nicer LLVM for the common case of fn a pattern
1848 set_value_name(arg_datum.val, &bcx.name(name));
1849 bcx.fcx.lllocals.borrow_mut().insert(pat.id, arg_datum);
1852 // General path. Copy out the values that are used in the
1854 _match::bind_irrefutable_pat(bcx, pat, arg_datum.match_input(), arg_scope_id)
1856 debuginfo::create_argument_metadata(bcx, &args[i]);
1862 // Ties up the llstaticallocas -> llloadenv -> lltop edges,
1863 // and builds the return block.
1864 pub fn finish_fn<'blk, 'tcx>(fcx: &'blk FunctionContext<'blk, 'tcx>,
1865 last_bcx: Block<'blk, 'tcx>,
1866 retty: ty::FnOutput<'tcx>,
1867 ret_debug_loc: DebugLoc) {
1868 let _icx = push_ctxt("finish_fn");
1870 let ret_cx = match fcx.llreturn.get() {
1872 if !last_bcx.terminated.get() {
1873 Br(last_bcx, llreturn, DebugLoc::None);
1875 raw_block(fcx, false, llreturn)
1880 // This shouldn't need to recompute the return type,
1881 // as new_fn_ctxt did it already.
1882 let substd_retty = fcx.monomorphize(&retty);
1883 build_return_block(fcx, ret_cx, substd_retty, ret_debug_loc);
1885 debuginfo::clear_source_location(fcx);
1889 // Builds the return block for a function.
1890 pub fn build_return_block<'blk, 'tcx>(fcx: &FunctionContext<'blk, 'tcx>,
1891 ret_cx: Block<'blk, 'tcx>,
1892 retty: ty::FnOutput<'tcx>,
1893 ret_debug_location: DebugLoc) {
1894 if fcx.llretslotptr.get().is_none() ||
1895 (!fcx.needs_ret_allocas && fcx.caller_expects_out_pointer) {
1896 return RetVoid(ret_cx, ret_debug_location);
1899 let retslot = if fcx.needs_ret_allocas {
1900 Load(ret_cx, fcx.llretslotptr.get().unwrap())
1902 fcx.llretslotptr.get().unwrap()
1904 let retptr = Value(retslot);
1905 match retptr.get_dominating_store(ret_cx) {
1906 // If there's only a single store to the ret slot, we can directly return
1907 // the value that was stored and omit the store and the alloca
1909 let retval = s.get_operand(0).unwrap().get();
1910 s.erase_from_parent();
1912 if retptr.has_no_uses() {
1913 retptr.erase_from_parent();
1916 let retval = if retty == ty::FnConverging(fcx.ccx.tcx().types.bool) {
1917 Trunc(ret_cx, retval, Type::i1(fcx.ccx))
1922 if fcx.caller_expects_out_pointer {
1923 if let ty::FnConverging(retty) = retty {
1924 store_ty(ret_cx, retval, get_param(fcx.llfn, 0), retty);
1926 RetVoid(ret_cx, ret_debug_location)
1928 Ret(ret_cx, retval, ret_debug_location)
1931 // Otherwise, copy the return value to the ret slot
1932 None => match retty {
1933 ty::FnConverging(retty) => {
1934 if fcx.caller_expects_out_pointer {
1935 memcpy_ty(ret_cx, get_param(fcx.llfn, 0), retslot, retty);
1936 RetVoid(ret_cx, ret_debug_location)
1938 Ret(ret_cx, load_ty(ret_cx, retslot, retty), ret_debug_location)
1941 ty::FnDiverging => {
1942 if fcx.caller_expects_out_pointer {
1943 RetVoid(ret_cx, ret_debug_location)
1945 Ret(ret_cx, C_undef(Type::nil(fcx.ccx)), ret_debug_location)
1952 /// Builds an LLVM function out of a source function.
1954 /// If the function closes over its environment a closure will be returned.
1955 pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1959 param_substs: &'tcx Substs<'tcx>,
1960 fn_ast_id: ast::NodeId,
1961 attributes: &[ast::Attribute],
1962 output_type: ty::FnOutput<'tcx>,
1964 closure_env: closure::ClosureEnv<'b>) {
1965 ccx.stats().n_closures.set(ccx.stats().n_closures.get() + 1);
1967 let _icx = push_ctxt("trans_closure");
1968 attributes::emit_uwtable(llfndecl, true);
1970 debug!("trans_closure(..., param_substs={:?})", param_substs);
1972 let has_env = match closure_env {
1973 closure::ClosureEnv::Closure(..) => true,
1974 closure::ClosureEnv::NotClosure => false,
1977 let (arena, fcx): (TypedArena<_>, FunctionContext);
1978 arena = TypedArena::new();
1979 fcx = new_fn_ctxt(ccx,
1987 let mut bcx = init_function(&fcx, false, output_type);
1989 if attributes.iter().any(|item| item.check_name("rustc_mir")) {
1990 mir::trans_mir(bcx);
1995 // cleanup scope for the incoming arguments
1996 let fn_cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(ccx,
2000 let arg_scope = fcx.push_custom_cleanup_scope_with_debug_loc(fn_cleanup_debug_loc);
2002 let block_ty = node_id_type(bcx, body.id);
2004 // Set up arguments to the function.
2005 let monomorphized_arg_types = decl.inputs
2007 .map(|arg| node_id_type(bcx, arg.id))
2008 .collect::<Vec<_>>();
2009 for monomorphized_arg_type in &monomorphized_arg_types {
2010 debug!("trans_closure: monomorphized_arg_type: {:?}",
2011 monomorphized_arg_type);
2013 debug!("trans_closure: function lltype: {}",
2014 bcx.fcx.ccx.tn().val_to_string(bcx.fcx.llfn));
2016 let has_tupled_arg = match closure_env {
2017 closure::ClosureEnv::NotClosure => abi == RustCall,
2021 bcx = create_datums_for_fn_args(bcx,
2023 &monomorphized_arg_types,
2027 bcx = closure_env.load(bcx, cleanup::CustomScope(arg_scope));
2029 // Up until here, IR instructions for this function have explicitly not been annotated with
2030 // source code location, so we don't step into call setup code. From here on, source location
2031 // emitting should be enabled.
2032 debuginfo::start_emitting_source_locations(&fcx);
2034 let dest = match fcx.llretslotptr.get() {
2035 Some(_) => expr::SaveIn(fcx.get_ret_slot(bcx, ty::FnConverging(block_ty), "iret_slot")),
2037 assert!(type_is_zero_size(bcx.ccx(), block_ty));
2042 // This call to trans_block is the place where we bridge between
2043 // translation calls that don't have a return value (trans_crate,
2044 // trans_mod, trans_item, et cetera) and those that do
2045 // (trans_block, trans_expr, et cetera).
2046 bcx = controlflow::trans_block(bcx, body, dest);
2049 expr::SaveIn(slot) if fcx.needs_ret_allocas => {
2050 Store(bcx, slot, fcx.llretslotptr.get().unwrap());
2055 match fcx.llreturn.get() {
2057 Br(bcx, fcx.return_exit_block(), DebugLoc::None);
2058 fcx.pop_custom_cleanup_scope(arg_scope);
2061 // Microoptimization writ large: avoid creating a separate
2062 // llreturn basic block
2063 bcx = fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_scope);
2067 // Put return block after all other blocks.
2068 // This somewhat improves single-stepping experience in debugger.
2070 let llreturn = fcx.llreturn.get();
2071 if let Some(llreturn) = llreturn {
2072 llvm::LLVMMoveBasicBlockAfter(llreturn, bcx.llbb);
2076 let ret_debug_loc = DebugLoc::At(fn_cleanup_debug_loc.id, fn_cleanup_debug_loc.span);
2078 // Insert the mandatory first few basic blocks before lltop.
2079 finish_fn(&fcx, bcx, output_type, ret_debug_loc);
2082 /// Creates an LLVM function corresponding to a source language function.
2083 pub fn trans_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2087 param_substs: &'tcx Substs<'tcx>,
2089 attrs: &[ast::Attribute]) {
2090 let _s = StatRecorder::new(ccx, ccx.tcx().map.path_to_string(id).to_string());
2091 debug!("trans_fn(param_substs={:?})", param_substs);
2092 let _icx = push_ctxt("trans_fn");
2093 let fn_ty = ccx.tcx().node_id_to_type(id);
2094 let fn_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &fn_ty);
2095 let sig = fn_ty.fn_sig();
2096 let sig = ccx.tcx().erase_late_bound_regions(&sig);
2097 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
2098 let output_type = sig.output;
2099 let abi = fn_ty.fn_abi();
2109 closure::ClosureEnv::NotClosure);
2112 pub fn trans_enum_variant<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2113 ctor_id: ast::NodeId,
2115 param_substs: &'tcx Substs<'tcx>,
2116 llfndecl: ValueRef) {
2117 let _icx = push_ctxt("trans_enum_variant");
2119 trans_enum_variant_or_tuple_like_struct(ccx, ctor_id, disr, param_substs, llfndecl);
2122 pub fn trans_named_tuple_constructor<'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
2125 args: callee::CallArgs,
2127 debug_loc: DebugLoc)
2128 -> Result<'blk, 'tcx> {
2130 let ccx = bcx.fcx.ccx;
2132 let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
2133 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
2134 let result_ty = sig.output.unwrap();
2136 // Get location to store the result. If the user does not care about
2137 // the result, just make a stack slot
2138 let llresult = match dest {
2139 expr::SaveIn(d) => d,
2141 if !type_is_zero_size(ccx, result_ty) {
2142 let llresult = alloc_ty(bcx, result_ty, "constructor_result");
2143 call_lifetime_start(bcx, llresult);
2146 C_undef(type_of::type_of(ccx, result_ty).ptr_to())
2151 if !type_is_zero_size(ccx, result_ty) {
2153 callee::ArgExprs(exprs) => {
2154 let fields = exprs.iter().map(|x| &**x).enumerate().collect::<Vec<_>>();
2155 bcx = expr::trans_adt(bcx,
2160 expr::SaveIn(llresult),
2163 _ => ccx.sess().bug("expected expr as arguments for variant/struct tuple constructor"),
2166 // Just eval all the expressions (if any). Since expressions in Rust can have arbitrary
2167 // contents, there could be side-effects we need from them.
2169 callee::ArgExprs(exprs) => {
2171 bcx = expr::trans_into(bcx, expr, expr::Ignore);
2178 // If the caller doesn't care about the result
2179 // drop the temporary we made
2180 let bcx = match dest {
2181 expr::SaveIn(_) => bcx,
2183 let bcx = glue::drop_ty(bcx, llresult, result_ty, debug_loc);
2184 if !type_is_zero_size(ccx, result_ty) {
2185 call_lifetime_end(bcx, llresult);
2191 Result::new(bcx, llresult)
2194 pub fn trans_tuple_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2195 ctor_id: ast::NodeId,
2196 param_substs: &'tcx Substs<'tcx>,
2197 llfndecl: ValueRef) {
2198 let _icx = push_ctxt("trans_tuple_struct");
2200 trans_enum_variant_or_tuple_like_struct(ccx, ctor_id, 0, param_substs, llfndecl);
2203 fn trans_enum_variant_or_tuple_like_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2204 ctor_id: ast::NodeId,
2206 param_substs: &'tcx Substs<'tcx>,
2207 llfndecl: ValueRef) {
2208 let ctor_ty = ccx.tcx().node_id_to_type(ctor_id);
2209 let ctor_ty = monomorphize::apply_param_substs(ccx.tcx(), param_substs, &ctor_ty);
2211 let sig = ccx.tcx().erase_late_bound_regions(&ctor_ty.fn_sig());
2212 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
2213 let arg_tys = sig.inputs;
2214 let result_ty = sig.output;
2216 let (arena, fcx): (TypedArena<_>, FunctionContext);
2217 arena = TypedArena::new();
2218 fcx = new_fn_ctxt(ccx,
2226 let bcx = init_function(&fcx, false, result_ty);
2228 assert!(!fcx.needs_ret_allocas);
2230 if !type_is_zero_size(fcx.ccx, result_ty.unwrap()) {
2231 let dest = fcx.get_ret_slot(bcx, result_ty, "eret_slot");
2232 let dest_val = adt::MaybeSizedValue::sized(dest); // Can return unsized value
2233 let repr = adt::represent_type(ccx, result_ty.unwrap());
2234 let mut llarg_idx = fcx.arg_offset() as c_uint;
2235 for (i, arg_ty) in arg_tys.into_iter().enumerate() {
2236 let lldestptr = adt::trans_field_ptr(bcx, &*repr, dest_val, disr, i);
2237 if common::type_is_fat_ptr(bcx.tcx(), arg_ty) {
2239 get_param(fcx.llfn, llarg_idx),
2240 expr::get_dataptr(bcx, lldestptr));
2242 get_param(fcx.llfn, llarg_idx + 1),
2243 expr::get_meta(bcx, lldestptr));
2246 let arg = get_param(fcx.llfn, llarg_idx);
2249 if arg_is_indirect(ccx, arg_ty) {
2250 memcpy_ty(bcx, lldestptr, arg, arg_ty);
2252 store_ty(bcx, arg, lldestptr, arg_ty);
2256 adt::trans_set_discr(bcx, &*repr, dest, disr);
2259 finish_fn(&fcx, bcx, result_ty, DebugLoc::None);
2262 fn enum_variant_size_lint(ccx: &CrateContext, enum_def: &hir::EnumDef, sp: Span, id: ast::NodeId) {
2263 let mut sizes = Vec::new(); // does no allocation if no pushes, thankfully
2265 let print_info = ccx.sess().print_enum_sizes();
2267 let levels = ccx.tcx().node_lint_levels.borrow();
2268 let lint_id = lint::LintId::of(lint::builtin::VARIANT_SIZE_DIFFERENCES);
2269 let lvlsrc = levels.get(&(id, lint_id));
2270 let is_allow = lvlsrc.map_or(true, |&(lvl, _)| lvl == lint::Allow);
2272 if is_allow && !print_info {
2273 // we're not interested in anything here
2277 let ty = ccx.tcx().node_id_to_type(id);
2278 let avar = adt::represent_type(ccx, ty);
2280 adt::General(_, ref variants, _) => {
2281 for var in variants {
2283 for field in var.fields.iter().skip(1) {
2284 // skip the discriminant
2285 size += llsize_of_real(ccx, sizing_type_of(ccx, *field));
2290 _ => { /* its size is either constant or unimportant */ }
2293 let (largest, slargest, largest_index) = sizes.iter().enumerate().fold((0, 0, 0),
2294 |(l, s, li), (idx, &size)|
2297 } else if size > s {
2304 // FIXME(#30505) Should use logging for this.
2306 let llty = type_of::sizing_type_of(ccx, ty);
2308 let sess = &ccx.tcx().sess;
2309 sess.span_note_without_error(sp,
2310 &*format!("total size: {} bytes", llsize_of_real(ccx, llty)));
2312 adt::General(..) => {
2313 for (i, var) in enum_def.variants.iter().enumerate() {
2316 .span_note_without_error(var.span,
2317 &*format!("variant data: {} bytes", sizes[i]));
2324 // we only warn if the largest variant is at least thrice as large as
2325 // the second-largest.
2326 if !is_allow && largest > slargest * 3 && slargest > 0 {
2327 // Use lint::raw_emit_lint rather than sess.add_lint because the lint-printing
2328 // pass for the latter already ran.
2329 lint::raw_struct_lint(&ccx.tcx().sess,
2330 &ccx.tcx().sess.lint_store.borrow(),
2331 lint::builtin::VARIANT_SIZE_DIFFERENCES,
2334 &format!("enum variant is more than three times larger ({} bytes) \
2335 than the next largest (ignoring padding)",
2337 .span_note(enum_def.variants[largest_index].span,
2338 "this variant is the largest")
2343 pub fn llvm_linkage_by_name(name: &str) -> Option<Linkage> {
2344 // Use the names from src/llvm/docs/LangRef.rst here. Most types are only
2345 // applicable to variable declarations and may not really make sense for
2346 // Rust code in the first place but whitelist them anyway and trust that
2347 // the user knows what s/he's doing. Who knows, unanticipated use cases
2348 // may pop up in the future.
2350 // ghost, dllimport, dllexport and linkonce_odr_autohide are not supported
2351 // and don't have to be, LLVM treats them as no-ops.
2353 "appending" => Some(llvm::AppendingLinkage),
2354 "available_externally" => Some(llvm::AvailableExternallyLinkage),
2355 "common" => Some(llvm::CommonLinkage),
2356 "extern_weak" => Some(llvm::ExternalWeakLinkage),
2357 "external" => Some(llvm::ExternalLinkage),
2358 "internal" => Some(llvm::InternalLinkage),
2359 "linkonce" => Some(llvm::LinkOnceAnyLinkage),
2360 "linkonce_odr" => Some(llvm::LinkOnceODRLinkage),
2361 "private" => Some(llvm::PrivateLinkage),
2362 "weak" => Some(llvm::WeakAnyLinkage),
2363 "weak_odr" => Some(llvm::WeakODRLinkage),
2369 /// Enum describing the origin of an LLVM `Value`, for linkage purposes.
2370 #[derive(Copy, Clone)]
2371 pub enum ValueOrigin {
2372 /// The LLVM `Value` is in this context because the corresponding item was
2373 /// assigned to the current compilation unit.
2374 OriginalTranslation,
2375 /// The `Value`'s corresponding item was assigned to some other compilation
2376 /// unit, but the `Value` was translated in this context anyway because the
2377 /// item is marked `#[inline]`.
2381 /// Set the appropriate linkage for an LLVM `ValueRef` (function or global).
2382 /// If the `llval` is the direct translation of a specific Rust item, `id`
2383 /// should be set to the `NodeId` of that item. (This mapping should be
2384 /// 1-to-1, so monomorphizations and drop/visit glue should have `id` set to
2385 /// `None`.) `llval_origin` indicates whether `llval` is the translation of an
2386 /// item assigned to `ccx`'s compilation unit or an inlined copy of an item
2387 /// assigned to a different compilation unit.
2388 pub fn update_linkage(ccx: &CrateContext,
2390 id: Option<ast::NodeId>,
2391 llval_origin: ValueOrigin) {
2392 match llval_origin {
2394 // `llval` is a translation of an item defined in a separate
2395 // compilation unit. This only makes sense if there are at least
2396 // two compilation units.
2397 assert!(ccx.sess().opts.cg.codegen_units > 1);
2398 // `llval` is a copy of something defined elsewhere, so use
2399 // `AvailableExternallyLinkage` to avoid duplicating code in the
2401 llvm::SetLinkage(llval, llvm::AvailableExternallyLinkage);
2404 OriginalTranslation => {},
2407 if let Some(id) = id {
2408 let item = ccx.tcx().map.get(id);
2409 if let hir_map::NodeItem(i) = item {
2410 if let Some(name) = attr::first_attr_value_str_by_name(&i.attrs, "linkage") {
2411 if let Some(linkage) = llvm_linkage_by_name(&name) {
2412 llvm::SetLinkage(llval, linkage);
2414 ccx.sess().span_fatal(i.span, "invalid linkage specified");
2422 Some(id) if ccx.reachable().contains(&id) => {
2423 llvm::SetLinkage(llval, llvm::ExternalLinkage);
2426 // `id` does not refer to an item in `ccx.reachable`.
2427 if ccx.sess().opts.cg.codegen_units > 1 {
2428 llvm::SetLinkage(llval, llvm::ExternalLinkage);
2430 llvm::SetLinkage(llval, llvm::InternalLinkage);
2436 fn set_global_section(ccx: &CrateContext, llval: ValueRef, i: &hir::Item) {
2437 match attr::first_attr_value_str_by_name(&i.attrs, "link_section") {
2439 if contains_null(§) {
2440 ccx.sess().fatal(&format!("Illegal null byte in link_section value: `{}`", §));
2443 let buf = CString::new(sect.as_bytes()).unwrap();
2444 llvm::LLVMSetSection(llval, buf.as_ptr());
2451 pub fn trans_item(ccx: &CrateContext, item: &hir::Item) {
2452 let _icx = push_ctxt("trans_item");
2454 let from_external = ccx.external_srcs().borrow().contains_key(&item.id);
2457 hir::ItemFn(ref decl, _, _, abi, ref generics, ref body) => {
2458 if !generics.is_type_parameterized() {
2459 let trans_everywhere = attr::requests_inline(&item.attrs);
2460 // Ignore `trans_everywhere` for cross-crate inlined items
2461 // (`from_external`). `trans_item` will be called once for each
2462 // compilation unit that references the item, so it will still get
2463 // translated everywhere it's needed.
2464 for (ref ccx, is_origin) in ccx.maybe_iter(!from_external && trans_everywhere) {
2465 let llfn = get_item_val(ccx, item.id);
2466 let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
2468 foreign::trans_rust_fn_with_foreign_abi(ccx,
2485 set_global_section(ccx, llfn, item);
2495 if is_entry_fn(ccx.sess(), item.id) {
2496 create_entry_wrapper(ccx, item.span, llfn);
2497 // check for the #[rustc_error] annotation, which forces an
2498 // error in trans. This is used to write compile-fail tests
2499 // that actually test that compilation succeeds without
2500 // reporting an error.
2501 let item_def_id = ccx.tcx().map.local_def_id(item.id);
2502 if ccx.tcx().has_attr(item_def_id, "rustc_error") {
2503 ccx.tcx().sess.span_fatal(item.span, "compilation successful");
2509 hir::ItemImpl(_, _, ref generics, _, _, ref impl_items) => {
2510 meth::trans_impl(ccx, item.name, impl_items, generics, item.id);
2512 hir::ItemMod(_) => {
2513 // modules have no equivalent at runtime, they just affect
2514 // the mangled names of things contained within
2516 hir::ItemEnum(ref enum_definition, ref gens) => {
2517 if gens.ty_params.is_empty() {
2518 // sizes only make sense for non-generic types
2520 enum_variant_size_lint(ccx, enum_definition, item.span, item.id);
2523 hir::ItemConst(..) => {}
2524 hir::ItemStatic(_, m, ref expr) => {
2525 let g = match consts::trans_static(ccx, m, expr, item.id, &item.attrs) {
2527 Err(err) => ccx.tcx().sess.span_fatal(expr.span, &err.description()),
2529 set_global_section(ccx, g, item);
2530 update_linkage(ccx, g, Some(item.id), OriginalTranslation);
2532 hir::ItemForeignMod(ref foreign_mod) => {
2533 foreign::trans_foreign_mod(ccx, foreign_mod);
2535 hir::ItemTrait(..) => {}
2542 // only use this for foreign function ABIs and glue, use `register_fn` for Rust functions
2543 pub fn register_fn_llvmty(ccx: &CrateContext,
2546 node_id: ast::NodeId,
2550 debug!("register_fn_llvmty id={} sym={}", node_id, sym);
2552 let llfn = declare::define_fn(ccx, &sym[..], cc, llfty,
2553 ty::FnConverging(ccx.tcx().mk_nil())).unwrap_or_else(||{
2554 ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym));
2556 finish_register_fn(ccx, sym, node_id);
2560 fn finish_register_fn(ccx: &CrateContext, sym: String, node_id: ast::NodeId) {
2561 ccx.item_symbols().borrow_mut().insert(node_id, sym);
2564 fn register_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2567 node_id: ast::NodeId,
2568 node_type: Ty<'tcx>)
2570 if let ty::TyBareFn(_, ref f) = node_type.sty {
2571 if f.abi != Rust && f.abi != RustCall {
2572 ccx.sess().span_bug(sp,
2573 &format!("only the `{}` or `{}` calling conventions are valid \
2574 for this function; `{}` was specified",
2580 ccx.sess().span_bug(sp, "expected bare rust function")
2583 let llfn = declare::define_rust_fn(ccx, &sym[..], node_type).unwrap_or_else(|| {
2584 ccx.sess().span_fatal(sp, &format!("symbol `{}` is already defined", sym));
2586 finish_register_fn(ccx, sym, node_id);
2590 pub fn is_entry_fn(sess: &Session, node_id: ast::NodeId) -> bool {
2591 match *sess.entry_fn.borrow() {
2592 Some((entry_id, _)) => node_id == entry_id,
2597 /// Create the `main` function which will initialise the rust runtime and call users’ main
2599 pub fn create_entry_wrapper(ccx: &CrateContext, sp: Span, main_llfn: ValueRef) {
2600 let et = ccx.sess().entry_type.get().unwrap();
2602 config::EntryMain => {
2603 create_entry_fn(ccx, sp, main_llfn, true);
2605 config::EntryStart => create_entry_fn(ccx, sp, main_llfn, false),
2606 config::EntryNone => {} // Do nothing.
2609 fn create_entry_fn(ccx: &CrateContext,
2611 rust_main: ValueRef,
2612 use_start_lang_item: bool) {
2613 let llfty = Type::func(&[ccx.int_type(), Type::i8p(ccx).ptr_to()], &ccx.int_type());
2615 let llfn = declare::define_cfn(ccx, "main", llfty, ccx.tcx().mk_nil()).unwrap_or_else(|| {
2616 // FIXME: We should be smart and show a better diagnostic here.
2617 ccx.sess().struct_span_err(sp, "entry symbol `main` defined multiple times")
2618 .help("did you use #[no_mangle] on `fn main`? Use #[start] instead")
2620 ccx.sess().abort_if_errors();
2625 llvm::LLVMAppendBasicBlockInContext(ccx.llcx(), llfn, "top\0".as_ptr() as *const _)
2627 let bld = ccx.raw_builder();
2629 llvm::LLVMPositionBuilderAtEnd(bld, llbb);
2631 debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx);
2633 let (start_fn, args) = if use_start_lang_item {
2634 let start_def_id = match ccx.tcx().lang_items.require(StartFnLangItem) {
2637 ccx.sess().fatal(&s[..]);
2640 let start_fn = if let Some(start_node_id) = ccx.tcx()
2642 .as_local_node_id(start_def_id) {
2643 get_item_val(ccx, start_node_id)
2645 let start_fn_type = ccx.tcx().lookup_item_type(start_def_id).ty;
2646 trans_external_path(ccx, start_def_id, start_fn_type)
2649 let opaque_rust_main =
2650 llvm::LLVMBuildPointerCast(bld,
2652 Type::i8p(ccx).to_ref(),
2653 "rust_main\0".as_ptr() as *const _);
2655 vec![opaque_rust_main, get_param(llfn, 0), get_param(llfn, 1)]
2659 debug!("using user-defined start fn");
2660 let args = vec![get_param(llfn, 0 as c_uint), get_param(llfn, 1 as c_uint)];
2665 let result = llvm::LLVMBuildCall(bld,
2668 args.len() as c_uint,
2671 llvm::LLVMBuildRet(bld, result);
2676 fn exported_name<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
2679 attrs: &[ast::Attribute])
2681 match ccx.external_srcs().borrow().get(&id) {
2683 let sym = ccx.sess().cstore.item_symbol(did);
2684 debug!("found item {} in other crate...", sym);
2690 match attr::find_export_name_attr(ccx.sess().diagnostic(), attrs) {
2691 // Use provided name
2692 Some(name) => name.to_string(),
2694 let path = ccx.tcx().map.def_path_from_id(id);
2695 if attr::contains_name(attrs, "no_mangle") {
2697 path.last().unwrap().data.to_string()
2699 match weak_lang_items::link_name(attrs) {
2700 Some(name) => name.to_string(),
2702 // Usual name mangling
2703 mangle_exported_name(ccx, path, ty, id)
2711 fn contains_null(s: &str) -> bool {
2712 s.bytes().any(|b| b == 0)
2715 pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
2716 debug!("get_item_val(id=`{}`)", id);
2718 match ccx.item_vals().borrow().get(&id).cloned() {
2719 Some(v) => return v,
2723 let item = ccx.tcx().map.get(id);
2724 debug!("get_item_val: id={} item={:?}", id, item);
2725 let val = match item {
2726 hir_map::NodeItem(i) => {
2727 let ty = ccx.tcx().node_id_to_type(i.id);
2728 let sym = || exported_name(ccx, id, ty, &i.attrs);
2730 let v = match i.node {
2731 hir::ItemStatic(..) => {
2732 // If this static came from an external crate, then
2733 // we need to get the symbol from metadata instead of
2734 // using the current crate's name/version
2735 // information in the hash of the symbol
2737 debug!("making {}", sym);
2739 // Create the global before evaluating the initializer;
2740 // this is necessary to allow recursive statics.
2741 let llty = type_of(ccx, ty);
2742 let g = declare::define_global(ccx, &sym[..], llty).unwrap_or_else(|| {
2744 .span_fatal(i.span, &format!("symbol `{}` is already defined", sym))
2747 ccx.item_symbols().borrow_mut().insert(i.id, sym);
2751 hir::ItemFn(_, _, _, abi, _, _) => {
2753 let llfn = if abi == Rust {
2754 register_fn(ccx, i.span, sym, i.id, ty)
2756 foreign::register_rust_fn_with_foreign_abi(ccx, i.span, sym, i.id)
2758 attributes::from_fn_attrs(ccx, &i.attrs, llfn);
2762 _ => ccx.sess().bug("get_item_val: weird result in table"),
2768 hir_map::NodeTraitItem(trait_item) => {
2769 debug!("get_item_val(): processing a NodeTraitItem");
2770 match trait_item.node {
2771 hir::MethodTraitItem(_, Some(_)) => {
2772 register_method(ccx, id, &trait_item.attrs, trait_item.span)
2775 ccx.sess().span_bug(trait_item.span,
2776 "unexpected variant: trait item other than a provided \
2777 method in get_item_val()");
2782 hir_map::NodeImplItem(impl_item) => {
2783 match impl_item.node {
2784 hir::ImplItemKind::Method(..) => {
2785 register_method(ccx, id, &impl_item.attrs, impl_item.span)
2788 ccx.sess().span_bug(impl_item.span,
2789 "unexpected variant: non-method impl item in \
2795 hir_map::NodeForeignItem(ni) => {
2797 hir::ForeignItemFn(..) => {
2798 let abi = ccx.tcx().map.get_foreign_abi(id);
2799 let ty = ccx.tcx().node_id_to_type(ni.id);
2800 let name = foreign::link_name(&*ni);
2801 foreign::register_foreign_item_fn(ccx, abi, ty, &name, &ni.attrs)
2803 hir::ForeignItemStatic(..) => {
2804 foreign::register_static(ccx, &*ni)
2809 hir_map::NodeVariant(ref v) => {
2811 let fields = if v.node.data.is_struct() {
2812 ccx.sess().bug("struct variant kind unexpected in get_item_val")
2814 v.node.data.fields()
2816 assert!(!fields.is_empty());
2817 let ty = ccx.tcx().node_id_to_type(id);
2818 let parent = ccx.tcx().map.get_parent(id);
2819 let enm = ccx.tcx().map.expect_item(parent);
2820 let sym = exported_name(ccx, id, ty, &enm.attrs);
2822 llfn = match enm.node {
2823 hir::ItemEnum(_, _) => {
2824 register_fn(ccx, (*v).span, sym, id, ty)
2826 _ => ccx.sess().bug("NodeVariant, shouldn't happen"),
2828 attributes::inline(llfn, attributes::InlineAttr::Hint);
2832 hir_map::NodeStructCtor(struct_def) => {
2833 // Only register the constructor if this is a tuple-like struct.
2834 let ctor_id = if struct_def.is_struct() {
2835 ccx.sess().bug("attempt to register a constructor of a non-tuple-like struct")
2839 let parent = ccx.tcx().map.get_parent(id);
2840 let struct_item = ccx.tcx().map.expect_item(parent);
2841 let ty = ccx.tcx().node_id_to_type(ctor_id);
2842 let sym = exported_name(ccx, id, ty, &struct_item.attrs);
2843 let llfn = register_fn(ccx, struct_item.span, sym, ctor_id, ty);
2844 attributes::inline(llfn, attributes::InlineAttr::Hint);
2849 ccx.sess().bug(&format!("get_item_val(): unexpected variant: {:?}", variant))
2853 // All LLVM globals and functions are initially created as external-linkage
2854 // declarations. If `trans_item`/`trans_fn` later turns the declaration
2855 // into a definition, it adjusts the linkage then (using `update_linkage`).
2857 // The exception is foreign items, which have their linkage set inside the
2858 // call to `foreign::register_*` above. We don't touch the linkage after
2859 // that (`foreign::trans_foreign_mod` doesn't adjust the linkage like the
2860 // other item translation functions do).
2862 ccx.item_vals().borrow_mut().insert(id, val);
2866 fn register_method(ccx: &CrateContext,
2868 attrs: &[ast::Attribute],
2871 let mty = ccx.tcx().node_id_to_type(id);
2873 let sym = exported_name(ccx, id, mty, &attrs);
2875 if let ty::TyBareFn(_, ref f) = mty.sty {
2876 let llfn = if f.abi == Rust || f.abi == RustCall {
2877 register_fn(ccx, span, sym, id, mty)
2879 foreign::register_rust_fn_with_foreign_abi(ccx, span, sym, id)
2881 attributes::from_fn_attrs(ccx, &attrs, llfn);
2884 ccx.sess().span_bug(span, "expected bare rust function");
2888 pub fn write_metadata<'a, 'tcx>(cx: &SharedCrateContext<'a, 'tcx>,
2890 reachable: &NodeSet,
2891 mir_map: &MirMap<'tcx>)
2895 let any_library = cx.sess()
2899 .any(|ty| *ty != config::CrateTypeExecutable);
2904 let cstore = &cx.tcx().sess.cstore;
2905 let metadata = cstore.encode_metadata(cx.tcx(),
2912 let mut compressed = cstore.metadata_encoding_version().to_vec();
2913 compressed.extend_from_slice(&flate::deflate_bytes(&metadata));
2915 let llmeta = C_bytes_in_context(cx.metadata_llcx(), &compressed[..]);
2916 let llconst = C_struct_in_context(cx.metadata_llcx(), &[llmeta], false);
2917 let name = format!("rust_metadata_{}_{}",
2918 cx.link_meta().crate_name,
2919 cx.link_meta().crate_hash);
2920 let buf = CString::new(name).unwrap();
2921 let llglobal = unsafe {
2922 llvm::LLVMAddGlobal(cx.metadata_llmod(), val_ty(llconst).to_ref(), buf.as_ptr())
2925 llvm::LLVMSetInitializer(llglobal, llconst);
2927 cx.tcx().sess.cstore.metadata_section_name(&cx.sess().target.target);
2928 let name = CString::new(name).unwrap();
2929 llvm::LLVMSetSection(llglobal, name.as_ptr())
2934 /// Find any symbols that are defined in one compilation unit, but not declared
2935 /// in any other compilation unit. Give these symbols internal linkage.
2936 fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet<&str>) {
2938 let mut declared = HashSet::new();
2940 // Collect all external declarations in all compilation units.
2941 for ccx in cx.iter() {
2942 for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) {
2943 let linkage = llvm::LLVMGetLinkage(val);
2944 // We only care about external declarations (not definitions)
2945 // and available_externally definitions.
2946 if !(linkage == llvm::ExternalLinkage as c_uint &&
2947 llvm::LLVMIsDeclaration(val) != 0) &&
2948 !(linkage == llvm::AvailableExternallyLinkage as c_uint) {
2952 let name = CStr::from_ptr(llvm::LLVMGetValueName(val))
2955 declared.insert(name);
2959 // Examine each external definition. If the definition is not used in
2960 // any other compilation unit, and is not reachable from other crates,
2961 // then give it internal linkage.
2962 for ccx in cx.iter() {
2963 for val in iter_globals(ccx.llmod()).chain(iter_functions(ccx.llmod())) {
2964 // We only care about external definitions.
2965 if !(llvm::LLVMGetLinkage(val) == llvm::ExternalLinkage as c_uint &&
2966 llvm::LLVMIsDeclaration(val) == 0) {
2970 let name = CStr::from_ptr(llvm::LLVMGetValueName(val))
2973 if !declared.contains(&name) &&
2974 !reachable.contains(str::from_utf8(&name).unwrap()) {
2975 llvm::SetLinkage(val, llvm::InternalLinkage);
2976 llvm::SetDLLStorageClass(val, llvm::DefaultStorageClass);
2983 // Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
2984 // This is required to satisfy `dllimport` references to static data in .rlibs
2985 // when using MSVC linker. We do this only for data, as linker can fix up
2986 // code references on its own.
2987 // See #26591, #27438
2988 fn create_imps(cx: &SharedCrateContext) {
2989 // The x86 ABI seems to require that leading underscores are added to symbol
2990 // names, so we need an extra underscore on 32-bit. There's also a leading
2991 // '\x01' here which disables LLVM's symbol mangling (e.g. no extra
2992 // underscores added in front).
2993 let prefix = if cx.sess().target.target.target_pointer_width == "32" {
2999 for ccx in cx.iter() {
3000 let exported: Vec<_> = iter_globals(ccx.llmod())
3002 llvm::LLVMGetLinkage(val) ==
3003 llvm::ExternalLinkage as c_uint &&
3004 llvm::LLVMIsDeclaration(val) == 0
3008 let i8p_ty = Type::i8p(&ccx);
3009 for val in exported {
3010 let name = CStr::from_ptr(llvm::LLVMGetValueName(val));
3011 let mut imp_name = prefix.as_bytes().to_vec();
3012 imp_name.extend(name.to_bytes());
3013 let imp_name = CString::new(imp_name).unwrap();
3014 let imp = llvm::LLVMAddGlobal(ccx.llmod(),
3016 imp_name.as_ptr() as *const _);
3017 let init = llvm::LLVMConstBitCast(val, i8p_ty.to_ref());
3018 llvm::LLVMSetInitializer(imp, init);
3019 llvm::SetLinkage(imp, llvm::ExternalLinkage);
3027 step: unsafe extern "C" fn(ValueRef) -> ValueRef,
3030 impl Iterator for ValueIter {
3031 type Item = ValueRef;
3033 fn next(&mut self) -> Option<ValueRef> {
3036 self.cur = unsafe { (self.step)(old) };
3044 fn iter_globals(llmod: llvm::ModuleRef) -> ValueIter {
3047 cur: llvm::LLVMGetFirstGlobal(llmod),
3048 step: llvm::LLVMGetNextGlobal,
3053 fn iter_functions(llmod: llvm::ModuleRef) -> ValueIter {
3056 cur: llvm::LLVMGetFirstFunction(llmod),
3057 step: llvm::LLVMGetNextFunction,
3062 /// The context provided lists a set of reachable ids as calculated by
3063 /// middle::reachable, but this contains far more ids and symbols than we're
3064 /// actually exposing from the object file. This function will filter the set in
3065 /// the context to the set of ids which correspond to symbols that are exposed
3066 /// from the object file being generated.
3068 /// This list is later used by linkers to determine the set of symbols needed to
3069 /// be exposed from a dynamic library and it's also encoded into the metadata.
3070 pub fn filter_reachable_ids(ccx: &SharedCrateContext) -> NodeSet {
3071 ccx.reachable().iter().map(|x| *x).filter(|id| {
3072 // First, only worry about nodes which have a symbol name
3073 ccx.item_symbols().borrow().contains_key(id)
3075 // Next, we want to ignore some FFI functions that are not exposed from
3076 // this crate. Reachable FFI functions can be lumped into two
3079 // 1. Those that are included statically via a static library
3080 // 2. Those included otherwise (e.g. dynamically or via a framework)
3082 // Although our LLVM module is not literally emitting code for the
3083 // statically included symbols, it's an export of our library which
3084 // needs to be passed on to the linker and encoded in the metadata.
3086 // As a result, if this id is an FFI item (foreign item) then we only
3087 // let it through if it's included statically.
3088 match ccx.tcx().map.get(id) {
3089 hir_map::NodeForeignItem(..) => {
3090 ccx.sess().cstore.is_statically_included_foreign_item(id)
3097 pub fn trans_crate<'tcx>(tcx: &ty::ctxt<'tcx>,
3098 mir_map: &MirMap<'tcx>,
3099 analysis: ty::CrateAnalysis)
3100 -> CrateTranslation {
3101 let _task = tcx.dep_graph.in_task(DepNode::TransCrate);
3103 // Be careful with this krate: obviously it gives access to the
3104 // entire contents of the krate. So if you push any subtasks of
3105 // `TransCrate`, you need to be careful to register "reads" of the
3106 // particular items that will be processed.
3107 let krate = tcx.map.krate();
3109 let ty::CrateAnalysis { export_map, reachable, name, .. } = analysis;
3111 let check_overflow = if let Some(v) = tcx.sess.opts.debugging_opts.force_overflow_checks {
3114 tcx.sess.opts.debug_assertions
3117 let check_dropflag = if let Some(v) = tcx.sess.opts.debugging_opts.force_dropflag_checks {
3120 tcx.sess.opts.debug_assertions
3123 // Before we touch LLVM, make sure that multithreading is enabled.
3125 use std::sync::Once;
3126 static INIT: Once = Once::new();
3127 static mut POISONED: bool = false;
3129 if llvm::LLVMStartMultithreaded() != 1 {
3130 // use an extra bool to make sure that all future usage of LLVM
3131 // cannot proceed despite the Once not running more than once.
3135 ::back::write::configure_llvm(&tcx.sess);
3139 tcx.sess.bug("couldn't enable multi-threaded LLVM");
3143 let link_meta = link::build_link_meta(&tcx.sess, krate, name);
3145 let codegen_units = tcx.sess.opts.cg.codegen_units;
3146 let shared_ccx = SharedCrateContext::new(&link_meta.crate_name,
3158 let ccx = shared_ccx.get_ccx(0);
3160 // First, verify intrinsics.
3161 intrinsic::check_intrinsics(&ccx);
3163 // Next, translate all items. See `TransModVisitor` for
3164 // details on why we walk in this particular way.
3166 let _icx = push_ctxt("text");
3167 intravisit::walk_mod(&mut TransItemsWithinModVisitor { ccx: &ccx }, &krate.module);
3168 krate.visit_all_items(&mut TransModVisitor { ccx: &ccx });
3172 for ccx in shared_ccx.iter() {
3173 if ccx.sess().opts.debuginfo != NoDebugInfo {
3174 debuginfo::finalize(&ccx);
3176 for &(old_g, new_g) in ccx.statics_to_rauw().borrow().iter() {
3178 let bitcast = llvm::LLVMConstPointerCast(new_g, llvm::LLVMTypeOf(old_g));
3179 llvm::LLVMReplaceAllUsesWith(old_g, bitcast);
3180 llvm::LLVMDeleteGlobal(old_g);
3185 let reachable_symbol_ids = filter_reachable_ids(&shared_ccx);
3187 // Translate the metadata.
3188 let metadata = time(tcx.sess.time_passes(), "write metadata", || {
3189 write_metadata(&shared_ccx, krate, &reachable_symbol_ids, mir_map)
3192 if shared_ccx.sess().trans_stats() {
3193 let stats = shared_ccx.stats();
3194 println!("--- trans stats ---");
3195 println!("n_glues_created: {}", stats.n_glues_created.get());
3196 println!("n_null_glues: {}", stats.n_null_glues.get());
3197 println!("n_real_glues: {}", stats.n_real_glues.get());
3199 println!("n_fns: {}", stats.n_fns.get());
3200 println!("n_monos: {}", stats.n_monos.get());
3201 println!("n_inlines: {}", stats.n_inlines.get());
3202 println!("n_closures: {}", stats.n_closures.get());
3203 println!("fn stats:");
3204 stats.fn_stats.borrow_mut().sort_by(|&(_, insns_a), &(_, insns_b)| {
3205 insns_b.cmp(&insns_a)
3207 for tuple in stats.fn_stats.borrow().iter() {
3209 (ref name, insns) => {
3210 println!("{} insns, {}", insns, *name);
3215 if shared_ccx.sess().count_llvm_insns() {
3216 for (k, v) in shared_ccx.stats().llvm_insns.borrow().iter() {
3217 println!("{:7} {}", *v, *k);
3221 let modules = shared_ccx.iter()
3222 .map(|ccx| ModuleTranslation { llcx: ccx.llcx(), llmod: ccx.llmod() })
3225 let sess = shared_ccx.sess();
3226 let mut reachable_symbols = reachable_symbol_ids.iter().map(|id| {
3227 shared_ccx.item_symbols().borrow()[id].to_string()
3228 }).collect::<Vec<_>>();
3229 if sess.entry_fn.borrow().is_some() {
3230 reachable_symbols.push("main".to_string());
3233 // For the purposes of LTO, we add to the reachable set all of the upstream
3234 // reachable extern fns. These functions are all part of the public ABI of
3235 // the final product, so LTO needs to preserve them.
3237 for cnum in sess.cstore.crates() {
3238 let syms = sess.cstore.reachable_ids(cnum);
3239 reachable_symbols.extend(syms.into_iter().filter(|did| {
3240 sess.cstore.is_extern_fn(shared_ccx.tcx(), *did) ||
3241 sess.cstore.is_static(*did)
3243 sess.cstore.item_symbol(did)
3248 if codegen_units > 1 {
3249 internalize_symbols(&shared_ccx,
3250 &reachable_symbols.iter().map(|x| &x[..]).collect());
3253 if sess.target.target.options.is_like_msvc &&
3254 sess.crate_types.borrow().iter().any(|ct| *ct == config::CrateTypeRlib) {
3255 create_imps(&shared_ccx);
3258 let metadata_module = ModuleTranslation {
3259 llcx: shared_ccx.metadata_llcx(),
3260 llmod: shared_ccx.metadata_llmod(),
3262 let no_builtins = attr::contains_name(&krate.attrs, "no_builtins");
3264 assert_dep_graph::assert_dep_graph(tcx);
3268 metadata_module: metadata_module,
3271 reachable: reachable_symbols,
3272 no_builtins: no_builtins,
3276 /// We visit all the items in the krate and translate them. We do
3277 /// this in two walks. The first walk just finds module items. It then
3278 /// walks the full contents of those module items and translates all
3279 /// the items within. Note that this entire process is O(n). The
3280 /// reason for this two phased walk is that each module is
3281 /// (potentially) placed into a distinct codegen-unit. This walk also
3282 /// ensures that the immediate contents of each module is processed
3283 /// entirely before we proceed to find more modules, helping to ensure
3284 /// an equitable distribution amongst codegen-units.
3285 pub struct TransModVisitor<'a, 'tcx: 'a> {
3286 pub ccx: &'a CrateContext<'a, 'tcx>,
3289 impl<'a, 'tcx, 'v> Visitor<'v> for TransModVisitor<'a, 'tcx> {
3290 fn visit_item(&mut self, i: &hir::Item) {
3292 hir::ItemMod(_) => {
3293 let item_ccx = self.ccx.rotate();
3294 intravisit::walk_item(&mut TransItemsWithinModVisitor { ccx: &item_ccx }, i);
3301 /// Translates all the items within a given module. Expects owner to
3302 /// invoke `walk_item` on a module item. Ignores nested modules.
3303 pub struct TransItemsWithinModVisitor<'a, 'tcx: 'a> {
3304 pub ccx: &'a CrateContext<'a, 'tcx>,
3307 impl<'a, 'tcx, 'v> Visitor<'v> for TransItemsWithinModVisitor<'a, 'tcx> {
3308 fn visit_nested_item(&mut self, item_id: hir::ItemId) {
3309 self.visit_item(self.ccx.tcx().map.expect_item(item_id.id));
3312 fn visit_item(&mut self, i: &hir::Item) {
3314 hir::ItemMod(..) => {
3315 // skip modules, they will be uncovered by the TransModVisitor
3318 let def_id = self.ccx.tcx().map.local_def_id(i.id);
3319 let tcx = self.ccx.tcx();
3321 // Create a subtask for trans'ing a particular item. We are
3322 // giving `trans_item` access to this item, so also record a read.
3323 tcx.dep_graph.with_task(DepNode::TransCrateItem(def_id), || {
3324 tcx.dep_graph.read(DepNode::Hir(def_id));
3325 trans_item(self.ccx, i);
3328 intravisit::walk_item(self, i);