1 // Copyright 2012-2014 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.
11 //! # Translation of Expressions
13 //! The expr module handles translation of expressions. The most general
14 //! translation routine is `trans()`, which will translate an expression
15 //! into a datum. `trans_into()` is also available, which will translate
16 //! an expression and write the result directly into memory, sometimes
17 //! avoiding the need for a temporary stack slot. Finally,
18 //! `trans_to_lvalue()` is available if you'd like to ensure that the
19 //! result has cleanup scheduled.
21 //! Internally, each of these functions dispatches to various other
22 //! expression functions depending on the kind of expression. We divide
23 //! up expressions into:
25 //! - **Datum expressions:** Those that most naturally yield values.
26 //! Examples would be `22`, `box x`, or `a + b` (when not overloaded).
27 //! - **DPS expressions:** Those that most naturally write into a location
28 //! in memory. Examples would be `foo()` or `Point { x: 3, y: 4 }`.
29 //! - **Statement expressions:** That that do not generate a meaningful
30 //! result. Examples would be `while { ... }` or `return 44`.
32 //! Public entry points:
34 //! - `trans_into(bcx, expr, dest) -> bcx`: evaluates an expression,
35 //! storing the result into `dest`. This is the preferred form, if you
38 //! - `trans(bcx, expr) -> DatumBlock`: evaluates an expression, yielding
39 //! `Datum` with the result. You can then store the datum, inspect
40 //! the value, etc. This may introduce temporaries if the datum is a
43 //! - `trans_to_lvalue(bcx, expr, "...") -> DatumBlock`: evaluates an
44 //! expression and ensures that the result has a cleanup associated with it,
45 //! creating a temporary stack slot if necessary.
47 //! - `trans_local_var -> Datum`: looks up a local variable or upvar.
49 #![allow(non_camel_case_types)]
51 pub use self::Dest::*;
52 use self::lazy_binop_ty::*;
55 use llvm::{self, ValueRef, TypeKind};
56 use middle::const_qualif::ConstQualif;
58 use middle::subst::Substs;
59 use trans::{_match, adt, asm, base, callee, closure, consts, controlflow};
62 use trans::cleanup::{self, CleanupMethods, DropHintMethods};
65 use trans::debuginfo::{self, DebugLoc, ToDebugLoc};
73 use middle::ty::adjustment::{AdjustDerefRef, AdjustReifyFnPointer};
74 use middle::ty::adjustment::{AdjustUnsafeFnPointer, AdjustMutToConstPointer};
75 use middle::ty::adjustment::CustomCoerceUnsized;
76 use middle::ty::{self, Ty, TyCtxt};
77 use middle::ty::MethodCall;
78 use middle::ty::cast::{CastKind, CastTy};
79 use util::common::indenter;
80 use trans::machine::{llsize_of, llsize_of_alloc};
81 use trans::type_::Type;
86 use syntax::{ast, codemap};
87 use syntax::parse::token::InternedString;
89 use syntax::parse::token;
94 // These are passed around by the code generating functions to track the
95 // destination of a computation's value.
97 #[derive(Copy, Clone, PartialEq)]
104 pub fn to_string(&self, ccx: &CrateContext) -> String {
106 SaveIn(v) => format!("SaveIn({})", ccx.tn().val_to_string(v)),
107 Ignore => "Ignore".to_string()
112 /// This function is equivalent to `trans(bcx, expr).store_to_dest(dest)` but it may generate
113 /// better optimized LLVM code.
114 pub fn trans_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
117 -> Block<'blk, 'tcx> {
120 debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
122 if adjustment_required(bcx, expr) {
123 // use trans, which may be less efficient but
124 // which will perform the adjustments:
125 let datum = unpack_datum!(bcx, trans(bcx, expr));
126 return datum.store_to_dest(bcx, dest, expr.id);
129 let qualif = *bcx.tcx().const_qualif_map.borrow().get(&expr.id).unwrap();
130 if !qualif.intersects(ConstQualif::NOT_CONST | ConstQualif::NEEDS_DROP) {
131 if !qualif.intersects(ConstQualif::PREFER_IN_PLACE) {
132 if let SaveIn(lldest) = dest {
133 match consts::get_const_expr_as_global(bcx.ccx(), expr, qualif,
134 bcx.fcx.param_substs,
135 consts::TrueConst::No) {
137 // Cast pointer to destination, because constants
138 // have different types.
139 let lldest = PointerCast(bcx, lldest, val_ty(global));
140 memcpy_ty(bcx, lldest, global, expr_ty_adjusted(bcx, expr));
143 Err(consts::ConstEvalFailure::Runtime(_)) => {
144 // in case const evaluation errors, translate normally
145 // debug assertions catch the same errors
148 Err(consts::ConstEvalFailure::Compiletime(_)) => {
154 // If we see a const here, that's because it evaluates to a type with zero size. We
155 // should be able to just discard it, since const expressions are guaranteed not to
156 // have side effects. This seems to be reached through tuple struct constructors being
157 // passed zero-size constants.
158 if let hir::ExprPath(..) = expr.node {
159 match bcx.def(expr.id) {
160 Def::Const(_) | Def::AssociatedConst(_) => {
161 assert!(type_is_zero_size(bcx.ccx(), bcx.tcx().node_id_to_type(expr.id)));
168 // Even if we don't have a value to emit, and the expression
169 // doesn't have any side-effects, we still have to translate the
170 // body of any closures.
171 // FIXME: Find a better way of handling this case.
173 // The only way we're going to see a `const` at this point is if
174 // it prefers in-place instantiation, likely because it contains
175 // `[x; N]` somewhere within.
177 hir::ExprPath(..) => {
178 match bcx.def(expr.id) {
179 Def::Const(did) | Def::AssociatedConst(did) => {
180 let empty_substs = bcx.tcx().mk_substs(Substs::trans_empty());
181 let const_expr = consts::get_const_expr(bcx.ccx(), did, expr,
183 // Temporarily get cleanup scopes out of the way,
184 // as they require sub-expressions to be contained
185 // inside the current AST scope.
186 // These should record no cleanups anyways, `const`
187 // can't have destructors.
188 let scopes = mem::replace(&mut *bcx.fcx.scopes.borrow_mut(),
190 // Lock emitted debug locations to the location of
191 // the constant reference expression.
192 debuginfo::with_source_location_override(bcx.fcx,
195 bcx = trans_into(bcx, const_expr, dest)
197 let scopes = mem::replace(&mut *bcx.fcx.scopes.borrow_mut(),
199 assert!(scopes.is_empty());
210 debug!("trans_into() expr={:?}", expr);
212 let cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
216 bcx.fcx.push_ast_cleanup_scope(cleanup_debug_loc);
218 let kind = expr_kind(bcx.tcx(), expr);
220 ExprKind::Lvalue | ExprKind::RvalueDatum => {
221 trans_unadjusted(bcx, expr).store_to_dest(dest, expr.id)
223 ExprKind::RvalueDps => {
224 trans_rvalue_dps_unadjusted(bcx, expr, dest)
226 ExprKind::RvalueStmt => {
227 trans_rvalue_stmt_unadjusted(bcx, expr)
231 bcx.fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id)
234 /// Translates an expression, returning a datum (and new block) encapsulating the result. When
235 /// possible, it is preferred to use `trans_into`, as that may avoid creating a temporary on the
237 pub fn trans<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
239 -> DatumBlock<'blk, 'tcx, Expr> {
240 debug!("trans(expr={:?})", expr);
244 let qualif = *bcx.tcx().const_qualif_map.borrow().get(&expr.id).unwrap();
245 let adjusted_global = !qualif.intersects(ConstQualif::NON_STATIC_BORROWS);
246 let global = if !qualif.intersects(ConstQualif::NOT_CONST | ConstQualif::NEEDS_DROP) {
247 match consts::get_const_expr_as_global(bcx.ccx(), expr, qualif,
248 bcx.fcx.param_substs,
249 consts::TrueConst::No) {
251 if qualif.intersects(ConstQualif::HAS_STATIC_BORROWS) {
252 // Is borrowed as 'static, must return lvalue.
254 // Cast pointer to global, because constants have different types.
255 let const_ty = expr_ty_adjusted(bcx, expr);
256 let llty = type_of::type_of(bcx.ccx(), const_ty);
257 let global = PointerCast(bcx, global, llty.ptr_to());
258 let datum = Datum::new(global, const_ty, Lvalue::new("expr::trans"));
259 return DatumBlock::new(bcx, datum.to_expr_datum());
262 // Otherwise, keep around and perform adjustments, if needed.
263 let const_ty = if adjusted_global {
264 expr_ty_adjusted(bcx, expr)
269 // This could use a better heuristic.
270 Some(if type_is_immediate(bcx.ccx(), const_ty) {
271 // Cast pointer to global, because constants have different types.
272 let llty = type_of::type_of(bcx.ccx(), const_ty);
273 let global = PointerCast(bcx, global, llty.ptr_to());
274 // Maybe just get the value directly, instead of loading it?
275 immediate_rvalue(load_ty(bcx, global, const_ty), const_ty)
277 let scratch = alloc_ty(bcx, const_ty, "const");
278 call_lifetime_start(bcx, scratch);
279 let lldest = if !const_ty.is_structural() {
280 // Cast pointer to slot, because constants have different types.
281 PointerCast(bcx, scratch, val_ty(global))
283 // In this case, memcpy_ty calls llvm.memcpy after casting both
284 // source and destination to i8*, so we don't need any casts.
287 memcpy_ty(bcx, lldest, global, const_ty);
288 Datum::new(scratch, const_ty, Rvalue::new(ByRef))
291 Err(consts::ConstEvalFailure::Runtime(_)) => {
292 // in case const evaluation errors, translate normally
293 // debug assertions catch the same errors
297 Err(consts::ConstEvalFailure::Compiletime(_)) => {
298 // generate a dummy llvm value
299 let const_ty = expr_ty(bcx, expr);
300 let llty = type_of::type_of(bcx.ccx(), const_ty);
301 let dummy = C_undef(llty.ptr_to());
302 Some(Datum::new(dummy, const_ty, Rvalue::new(ByRef)))
309 let cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
313 fcx.push_ast_cleanup_scope(cleanup_debug_loc);
314 let datum = match global {
315 Some(rvalue) => rvalue.to_expr_datum(),
316 None => unpack_datum!(bcx, trans_unadjusted(bcx, expr))
318 let datum = if adjusted_global {
319 datum // trans::consts already performed adjustments.
321 unpack_datum!(bcx, apply_adjustments(bcx, expr, datum))
323 bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id);
324 return DatumBlock::new(bcx, datum);
327 pub fn get_meta(bcx: Block, fat_ptr: ValueRef) -> ValueRef {
328 StructGEP(bcx, fat_ptr, abi::FAT_PTR_EXTRA)
331 pub fn get_dataptr(bcx: Block, fat_ptr: ValueRef) -> ValueRef {
332 StructGEP(bcx, fat_ptr, abi::FAT_PTR_ADDR)
335 pub fn copy_fat_ptr(bcx: Block, src_ptr: ValueRef, dst_ptr: ValueRef) {
336 Store(bcx, Load(bcx, get_dataptr(bcx, src_ptr)), get_dataptr(bcx, dst_ptr));
337 Store(bcx, Load(bcx, get_meta(bcx, src_ptr)), get_meta(bcx, dst_ptr));
340 fn adjustment_required<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
341 expr: &hir::Expr) -> bool {
342 let adjustment = match bcx.tcx().tables.borrow().adjustments.get(&expr.id).cloned() {
343 None => { return false; }
347 // Don't skip a conversion from Box<T> to &T, etc.
348 if bcx.tcx().is_overloaded_autoderef(expr.id, 0) {
353 AdjustReifyFnPointer => {
354 // FIXME(#19925) once fn item types are
355 // zero-sized, we'll need to return true here
358 AdjustUnsafeFnPointer | AdjustMutToConstPointer => {
359 // purely a type-level thing
362 AdjustDerefRef(ref adj) => {
363 // We are a bit paranoid about adjustments and thus might have a re-
364 // borrow here which merely derefs and then refs again (it might have
365 // a different region or mutability, but we don't care here).
366 !(adj.autoderefs == 1 && adj.autoref.is_some() && adj.unsize.is_none())
371 /// Helper for trans that apply adjustments from `expr` to `datum`, which should be the unadjusted
372 /// translation of `expr`.
373 fn apply_adjustments<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
375 datum: Datum<'tcx, Expr>)
376 -> DatumBlock<'blk, 'tcx, Expr>
379 let mut datum = datum;
380 let adjustment = match bcx.tcx().tables.borrow().adjustments.get(&expr.id).cloned() {
382 return DatumBlock::new(bcx, datum);
386 debug!("unadjusted datum for expr {:?}: {} adjustment={:?}",
388 datum.to_string(bcx.ccx()),
391 AdjustReifyFnPointer => {
392 // FIXME(#19925) once fn item types are
393 // zero-sized, we'll need to do something here
395 AdjustUnsafeFnPointer | AdjustMutToConstPointer => {
396 // purely a type-level thing
398 AdjustDerefRef(ref adj) => {
399 let skip_reborrows = if adj.autoderefs == 1 && adj.autoref.is_some() {
400 // We are a bit paranoid about adjustments and thus might have a re-
401 // borrow here which merely derefs and then refs again (it might have
402 // a different region or mutability, but we don't care here).
404 // Don't skip a conversion from Box<T> to &T, etc.
406 if bcx.tcx().is_overloaded_autoderef(expr.id, 0) {
407 // Don't skip an overloaded deref.
419 if adj.autoderefs > skip_reborrows {
421 let lval = unpack_datum!(bcx, datum.to_lvalue_datum(bcx, "auto_deref", expr.id));
422 datum = unpack_datum!(bcx, deref_multiple(bcx, expr,
423 lval.to_expr_datum(),
424 adj.autoderefs - skip_reborrows));
427 // (You might think there is a more elegant way to do this than a
428 // skip_reborrows bool, but then you remember that the borrow checker exists).
429 if skip_reborrows == 0 && adj.autoref.is_some() {
430 datum = unpack_datum!(bcx, auto_ref(bcx, datum, expr));
433 if let Some(target) = adj.unsize {
434 // We do not arrange cleanup ourselves; if we already are an
435 // L-value, then cleanup will have already been scheduled (and
436 // the `datum.to_rvalue_datum` call below will emit code to zero
437 // the drop flag when moving out of the L-value). If we are an
438 // R-value, then we do not need to schedule cleanup.
439 let source_datum = unpack_datum!(bcx,
440 datum.to_rvalue_datum(bcx, "__coerce_source"));
442 let target = bcx.monomorphize(&target);
444 let scratch = alloc_ty(bcx, target, "__coerce_target");
445 call_lifetime_start(bcx, scratch);
446 let target_datum = Datum::new(scratch, target,
448 bcx = coerce_unsized(bcx, expr.span, source_datum, target_datum);
449 datum = Datum::new(scratch, target,
450 RvalueExpr(Rvalue::new(ByRef)));
454 debug!("after adjustments, datum={}", datum.to_string(bcx.ccx()));
455 DatumBlock::new(bcx, datum)
458 fn coerce_unsized<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
460 source: Datum<'tcx, Rvalue>,
461 target: Datum<'tcx, Rvalue>)
462 -> Block<'blk, 'tcx> {
464 debug!("coerce_unsized({} -> {})",
465 source.to_string(bcx.ccx()),
466 target.to_string(bcx.ccx()));
468 match (&source.ty.sty, &target.ty.sty) {
469 (&ty::TyBox(a), &ty::TyBox(b)) |
470 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
471 &ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) |
472 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
473 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
474 (&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
475 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
476 let (inner_source, inner_target) = (a, b);
478 let (base, old_info) = if !type_is_sized(bcx.tcx(), inner_source) {
479 // Normally, the source is a thin pointer and we are
480 // adding extra info to make a fat pointer. The exception
481 // is when we are upcasting an existing object fat pointer
482 // to use a different vtable. In that case, we want to
483 // load out the original data pointer so we can repackage
485 (Load(bcx, get_dataptr(bcx, source.val)),
486 Some(Load(bcx, get_meta(bcx, source.val))))
488 let val = if source.kind.is_by_ref() {
489 load_ty(bcx, source.val, source.ty)
496 let info = unsized_info(bcx.ccx(), inner_source, inner_target,
497 old_info, bcx.fcx.param_substs);
499 // Compute the base pointer. This doesn't change the pointer value,
500 // but merely its type.
501 let ptr_ty = type_of::in_memory_type_of(bcx.ccx(), inner_target).ptr_to();
502 let base = PointerCast(bcx, base, ptr_ty);
504 Store(bcx, base, get_dataptr(bcx, target.val));
505 Store(bcx, info, get_meta(bcx, target.val));
508 // This can be extended to enums and tuples in the future.
509 // (&ty::TyEnum(def_id_a, _), &ty::TyEnum(def_id_b, _)) |
510 (&ty::TyStruct(def_id_a, _), &ty::TyStruct(def_id_b, _)) => {
511 assert_eq!(def_id_a, def_id_b);
513 // The target is already by-ref because it's to be written to.
514 let source = unpack_datum!(bcx, source.to_ref_datum(bcx));
515 assert!(target.kind.is_by_ref());
517 let kind = custom_coerce_unsize_info(bcx.ccx(), source.ty, target.ty);
519 let repr_source = adt::represent_type(bcx.ccx(), source.ty);
520 let src_fields = match &*repr_source {
521 &adt::Repr::Univariant(ref s, _) => &s.fields,
522 _ => bcx.sess().span_bug(span,
523 &format!("Non univariant struct? (repr_source: {:?})",
526 let repr_target = adt::represent_type(bcx.ccx(), target.ty);
527 let target_fields = match &*repr_target {
528 &adt::Repr::Univariant(ref s, _) => &s.fields,
529 _ => bcx.sess().span_bug(span,
530 &format!("Non univariant struct? (repr_target: {:?})",
534 let coerce_index = match kind {
535 CustomCoerceUnsized::Struct(i) => i
537 assert!(coerce_index < src_fields.len() && src_fields.len() == target_fields.len());
539 let source_val = adt::MaybeSizedValue::sized(source.val);
540 let target_val = adt::MaybeSizedValue::sized(target.val);
542 let iter = src_fields.iter().zip(target_fields).enumerate();
543 for (i, (src_ty, target_ty)) in iter {
544 let ll_source = adt::trans_field_ptr(bcx, &repr_source, source_val, Disr(0), i);
545 let ll_target = adt::trans_field_ptr(bcx, &repr_target, target_val, Disr(0), i);
547 // If this is the field we need to coerce, recurse on it.
548 if i == coerce_index {
549 coerce_unsized(bcx, span,
550 Datum::new(ll_source, src_ty,
552 Datum::new(ll_target, target_ty,
553 Rvalue::new(ByRef)));
555 // Otherwise, simply copy the data from the source.
556 assert!(src_ty.is_phantom_data() || src_ty == target_ty);
557 memcpy_ty(bcx, ll_target, ll_source, src_ty);
561 _ => bcx.sess().bug(&format!("coerce_unsized: invalid coercion {:?} -> {:?}",
568 /// Translates an expression in "lvalue" mode -- meaning that it returns a reference to the memory
569 /// that the expr represents.
571 /// If this expression is an rvalue, this implies introducing a temporary. In other words,
572 /// something like `x().f` is translated into roughly the equivalent of
574 /// { tmp = x(); tmp.f }
575 pub fn trans_to_lvalue<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
578 -> DatumBlock<'blk, 'tcx, Lvalue> {
580 let datum = unpack_datum!(bcx, trans(bcx, expr));
581 return datum.to_lvalue_datum(bcx, name, expr.id);
584 /// A version of `trans` that ignores adjustments. You almost certainly do not want to call this
586 fn trans_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
588 -> DatumBlock<'blk, 'tcx, Expr> {
591 debug!("trans_unadjusted(expr={:?})", expr);
592 let _indenter = indenter();
594 debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
596 return match expr_kind(bcx.tcx(), expr) {
597 ExprKind::Lvalue | ExprKind::RvalueDatum => {
598 let datum = unpack_datum!(bcx, {
599 trans_datum_unadjusted(bcx, expr)
602 DatumBlock {bcx: bcx, datum: datum}
605 ExprKind::RvalueStmt => {
606 bcx = trans_rvalue_stmt_unadjusted(bcx, expr);
607 nil(bcx, expr_ty(bcx, expr))
610 ExprKind::RvalueDps => {
611 let ty = expr_ty(bcx, expr);
612 if type_is_zero_size(bcx.ccx(), ty) {
613 bcx = trans_rvalue_dps_unadjusted(bcx, expr, Ignore);
616 let scratch = rvalue_scratch_datum(bcx, ty, "");
617 bcx = trans_rvalue_dps_unadjusted(
618 bcx, expr, SaveIn(scratch.val));
620 // Note: this is not obviously a good idea. It causes
621 // immediate values to be loaded immediately after a
622 // return from a call or other similar expression,
623 // which in turn leads to alloca's having shorter
624 // lifetimes and hence larger stack frames. However,
625 // in turn it can lead to more register pressure.
626 // Still, in practice it seems to increase
627 // performance, since we have fewer problems with
629 let scratch = unpack_datum!(
630 bcx, scratch.to_appropriate_datum(bcx));
632 DatumBlock::new(bcx, scratch.to_expr_datum())
637 fn nil<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ty: Ty<'tcx>)
638 -> DatumBlock<'blk, 'tcx, Expr> {
639 let llval = C_undef(type_of::type_of(bcx.ccx(), ty));
640 let datum = immediate_rvalue(llval, ty);
641 DatumBlock::new(bcx, datum.to_expr_datum())
645 fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
647 -> DatumBlock<'blk, 'tcx, Expr> {
650 let _icx = push_ctxt("trans_datum_unadjusted");
653 hir::ExprType(ref e, _) => {
656 hir::ExprPath(..) => {
657 trans_def(bcx, expr, bcx.def(expr.id))
659 hir::ExprField(ref base, name) => {
660 trans_rec_field(bcx, &base, name.node)
662 hir::ExprTupField(ref base, idx) => {
663 trans_rec_tup_field(bcx, &base, idx.node)
665 hir::ExprIndex(ref base, ref idx) => {
666 trans_index(bcx, expr, &base, &idx, MethodCall::expr(expr.id))
668 hir::ExprBox(ref contents) => {
669 // Special case for `Box<T>`
670 let box_ty = expr_ty(bcx, expr);
671 let contents_ty = expr_ty(bcx, &contents);
674 trans_uniq_expr(bcx, expr, box_ty, &contents, contents_ty)
676 _ => bcx.sess().span_bug(expr.span,
677 "expected unique box")
681 hir::ExprLit(ref lit) => trans_immediate_lit(bcx, expr, &lit),
682 hir::ExprBinary(op, ref lhs, ref rhs) => {
683 trans_binary(bcx, expr, op, &lhs, &rhs)
685 hir::ExprUnary(op, ref x) => {
686 trans_unary(bcx, expr, op, &x)
688 hir::ExprAddrOf(_, ref x) => {
690 hir::ExprRepeat(..) | hir::ExprVec(..) => {
691 // Special case for slices.
692 let cleanup_debug_loc =
693 debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
697 fcx.push_ast_cleanup_scope(cleanup_debug_loc);
698 let datum = unpack_datum!(
699 bcx, tvec::trans_slice_vec(bcx, expr, &x));
700 bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, x.id);
701 DatumBlock::new(bcx, datum)
704 trans_addr_of(bcx, expr, &x)
708 hir::ExprCast(ref val, _) => {
709 // Datum output mode means this is a scalar cast:
710 trans_imm_cast(bcx, &val, expr.id)
713 bcx.tcx().sess.span_bug(
715 &format!("trans_rvalue_datum_unadjusted reached \
716 fall-through case: {:?}",
722 fn trans_field<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>,
725 -> DatumBlock<'blk, 'tcx, Expr> where
726 F: FnOnce(&'blk TyCtxt<'tcx>, &VariantInfo<'tcx>) -> usize,
729 let _icx = push_ctxt("trans_rec_field");
731 let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, base, "field"));
732 let bare_ty = base_datum.ty;
733 let repr = adt::represent_type(bcx.ccx(), bare_ty);
734 let vinfo = VariantInfo::from_ty(bcx.tcx(), bare_ty, None);
736 let ix = get_idx(bcx.tcx(), &vinfo);
737 let d = base_datum.get_element(
741 adt::trans_field_ptr(bcx, &repr, srcval, vinfo.discr, ix)
744 if type_is_sized(bcx.tcx(), d.ty) {
745 DatumBlock { datum: d.to_expr_datum(), bcx: bcx }
747 let scratch = rvalue_scratch_datum(bcx, d.ty, "");
748 Store(bcx, d.val, get_dataptr(bcx, scratch.val));
749 let info = Load(bcx, get_meta(bcx, base_datum.val));
750 Store(bcx, info, get_meta(bcx, scratch.val));
752 // Always generate an lvalue datum, because this pointer doesn't own
753 // the data and cleanup is scheduled elsewhere.
754 DatumBlock::new(bcx, Datum::new(scratch.val, scratch.ty, LvalueExpr(d.kind)))
758 /// Translates `base.field`.
759 fn trans_rec_field<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
762 -> DatumBlock<'blk, 'tcx, Expr> {
763 trans_field(bcx, base, |_, vinfo| vinfo.field_index(field))
766 /// Translates `base.<idx>`.
767 fn trans_rec_tup_field<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
770 -> DatumBlock<'blk, 'tcx, Expr> {
771 trans_field(bcx, base, |_, _| idx)
774 fn trans_index<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
775 index_expr: &hir::Expr,
778 method_call: MethodCall)
779 -> DatumBlock<'blk, 'tcx, Expr> {
780 //! Translates `base[idx]`.
782 let _icx = push_ctxt("trans_index");
786 let index_expr_debug_loc = index_expr.debug_loc();
788 // Check for overloaded index.
789 let method_ty = ccx.tcx()
794 .map(|method| method.ty);
795 let elt_datum = match method_ty {
797 let method_ty = monomorphize_type(bcx, method_ty);
799 let base_datum = unpack_datum!(bcx, trans(bcx, base));
801 // Translate index expression.
802 let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
804 let ref_ty = // invoked methods have LB regions instantiated:
805 bcx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
806 let elt_ty = match ref_ty.builtin_deref(true, ty::NoPreference) {
808 bcx.tcx().sess.span_bug(index_expr.span,
809 "index method didn't return a \
810 dereferenceable type?!")
812 Some(elt_tm) => elt_tm.ty,
815 // Overloaded. Evaluate `trans_overloaded_op`, which will
816 // invoke the user's index() method, which basically yields
817 // a `&T` pointer. We can then proceed down the normal
818 // path (below) to dereference that `&T`.
819 let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_index_elt");
821 trans_overloaded_op(bcx,
825 Some((ix_datum, idx.id)),
826 Some(SaveIn(scratch.val)),
828 let datum = scratch.to_expr_datum();
829 let lval = Lvalue::new("expr::trans_index overload");
830 if type_is_sized(bcx.tcx(), elt_ty) {
831 Datum::new(datum.to_llscalarish(bcx), elt_ty, LvalueExpr(lval))
833 Datum::new(datum.val, elt_ty, LvalueExpr(lval))
837 let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx,
841 // Translate index expression and cast to a suitable LLVM integer.
842 // Rust is less strict than LLVM in this regard.
843 let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
844 let ix_val = ix_datum.to_llscalarish(bcx);
845 let ix_size = machine::llbitsize_of_real(bcx.ccx(),
847 let int_size = machine::llbitsize_of_real(bcx.ccx(),
850 if ix_size < int_size {
851 if expr_ty(bcx, idx).is_signed() {
852 SExt(bcx, ix_val, ccx.int_type())
853 } else { ZExt(bcx, ix_val, ccx.int_type()) }
854 } else if ix_size > int_size {
855 Trunc(bcx, ix_val, ccx.int_type())
861 let unit_ty = base_datum.ty.sequence_element_type(bcx.tcx());
863 let (base, len) = base_datum.get_vec_base_and_len(bcx);
865 debug!("trans_index: base {}", bcx.val_to_string(base));
866 debug!("trans_index: len {}", bcx.val_to_string(len));
868 let bounds_check = ICmp(bcx,
872 index_expr_debug_loc);
873 let expect = ccx.get_intrinsic(&("llvm.expect.i1"));
874 let expected = Call(bcx,
876 &[bounds_check, C_bool(ccx, false)],
878 index_expr_debug_loc);
879 bcx = with_cond(bcx, expected, |bcx| {
880 controlflow::trans_fail_bounds_check(bcx,
881 expr_info(index_expr),
885 let elt = InBoundsGEP(bcx, base, &[ix_val]);
886 let elt = PointerCast(bcx, elt, type_of::type_of(ccx, unit_ty).ptr_to());
887 let lval = Lvalue::new("expr::trans_index fallback");
888 Datum::new(elt, unit_ty, LvalueExpr(lval))
892 DatumBlock::new(bcx, elt_datum)
895 fn trans_def<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
896 ref_expr: &hir::Expr,
898 -> DatumBlock<'blk, 'tcx, Expr> {
899 //! Translates a reference to a path.
901 let _icx = push_ctxt("trans_def_lvalue");
903 Def::Fn(..) | Def::Method(..) |
904 Def::Struct(..) | Def::Variant(..) => {
905 let datum = trans_def_fn_unadjusted(bcx.ccx(), ref_expr, def,
906 bcx.fcx.param_substs);
907 DatumBlock::new(bcx, datum.to_expr_datum())
909 Def::Static(did, _) => {
910 let const_ty = expr_ty(bcx, ref_expr);
911 let val = get_static_val(bcx.ccx(), did, const_ty);
912 let lval = Lvalue::new("expr::trans_def");
913 DatumBlock::new(bcx, Datum::new(val, const_ty, LvalueExpr(lval)))
915 Def::Const(_) | Def::AssociatedConst(_) => {
916 bcx.sess().span_bug(ref_expr.span,
917 "constant expression should not reach expr::trans_def")
920 DatumBlock::new(bcx, trans_local_var(bcx, def).to_expr_datum())
925 fn trans_rvalue_stmt_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
927 -> Block<'blk, 'tcx> {
929 let _icx = push_ctxt("trans_rvalue_stmt");
931 if bcx.unreachable.get() {
935 debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
938 hir::ExprBreak(label_opt) => {
939 controlflow::trans_break(bcx, expr, label_opt.map(|l| l.node.name))
941 hir::ExprType(ref e, _) => {
942 trans_into(bcx, &e, Ignore)
944 hir::ExprAgain(label_opt) => {
945 controlflow::trans_cont(bcx, expr, label_opt.map(|l| l.node.name))
947 hir::ExprRet(ref ex) => {
948 // Check to see if the return expression itself is reachable.
949 // This can occur when the inner expression contains a return
950 let reachable = if let Some(ref cfg) = bcx.fcx.cfg {
951 cfg.node_is_reachable(expr.id)
957 controlflow::trans_ret(bcx, expr, ex.as_ref().map(|e| &**e))
959 // If it's not reachable, just translate the inner expression
960 // directly. This avoids having to manage a return slot when
961 // it won't actually be used anyway.
962 if let &Some(ref x) = ex {
963 bcx = trans_into(bcx, &x, Ignore);
965 // Mark the end of the block as unreachable. Once we get to
966 // a return expression, there's no more we should be doing
972 hir::ExprWhile(ref cond, ref body, _) => {
973 controlflow::trans_while(bcx, expr, &cond, &body)
975 hir::ExprLoop(ref body, _) => {
976 controlflow::trans_loop(bcx, expr, &body)
978 hir::ExprAssign(ref dst, ref src) => {
979 let src_datum = unpack_datum!(bcx, trans(bcx, &src));
980 let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, &dst, "assign"));
982 if bcx.fcx.type_needs_drop(dst_datum.ty) {
983 // If there are destructors involved, make sure we
984 // are copying from an rvalue, since that cannot possible
985 // alias an lvalue. We are concerned about code like:
993 // where e.g. a : Option<Foo> and a.b :
994 // Option<Foo>. In that case, freeing `a` before the
995 // assignment may also free `a.b`!
997 // We could avoid this intermediary with some analysis
998 // to determine whether `dst` may possibly own `src`.
999 debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
1000 let src_datum = unpack_datum!(
1001 bcx, src_datum.to_rvalue_datum(bcx, "ExprAssign"));
1002 let opt_hint_datum = dst_datum.kind.drop_flag_info.hint_datum(bcx);
1003 let opt_hint_val = opt_hint_datum.map(|d|d.to_value());
1005 // 1. Drop the data at the destination, passing the
1006 // drop-hint in case the lvalue has already been
1007 // dropped or moved.
1008 bcx = glue::drop_ty_core(bcx,
1015 // 2. We are overwriting the destination; ensure that
1016 // its drop-hint (if any) says "initialized."
1017 if let Some(hint_val) = opt_hint_val {
1018 let hint_llval = hint_val.value();
1019 let drop_needed = C_u8(bcx.fcx.ccx, adt::DTOR_NEEDED_HINT);
1020 Store(bcx, drop_needed, hint_llval);
1022 src_datum.store_to(bcx, dst_datum.val)
1024 src_datum.store_to(bcx, dst_datum.val)
1027 hir::ExprAssignOp(op, ref dst, ref src) => {
1028 let has_method_map = bcx.tcx()
1032 .contains_key(&MethodCall::expr(expr.id));
1035 let dst = unpack_datum!(bcx, trans(bcx, &dst));
1036 let src_datum = unpack_datum!(bcx, trans(bcx, &src));
1037 trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id), dst,
1038 Some((src_datum, src.id)), None, false).bcx
1040 trans_assign_op(bcx, expr, op, &dst, &src)
1043 hir::ExprInlineAsm(ref a) => {
1044 asm::trans_inline_asm(bcx, a)
1047 bcx.tcx().sess.span_bug(
1049 &format!("trans_rvalue_stmt_unadjusted reached \
1050 fall-through case: {:?}",
1056 fn trans_rvalue_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1059 -> Block<'blk, 'tcx> {
1060 let _icx = push_ctxt("trans_rvalue_dps_unadjusted");
1062 let tcx = bcx.tcx();
1064 debuginfo::set_source_location(bcx.fcx, expr.id, expr.span);
1067 hir::ExprType(ref e, _) => {
1068 trans_into(bcx, &e, dest)
1070 hir::ExprPath(..) => {
1071 trans_def_dps_unadjusted(bcx, expr, bcx.def(expr.id), dest)
1073 hir::ExprIf(ref cond, ref thn, ref els) => {
1074 controlflow::trans_if(bcx, expr.id, &cond, &thn, els.as_ref().map(|e| &**e), dest)
1076 hir::ExprMatch(ref discr, ref arms, _) => {
1077 _match::trans_match(bcx, expr, &discr, &arms[..], dest)
1079 hir::ExprBlock(ref blk) => {
1080 controlflow::trans_block(bcx, &blk, dest)
1082 hir::ExprStruct(_, ref fields, ref base) => {
1085 base.as_ref().map(|e| &**e),
1088 node_id_type(bcx, expr.id),
1091 hir::ExprRange(ref start, ref end) => {
1092 // FIXME it is just not right that we are synthesising ast nodes in
1094 fn make_field(field_name: &str, expr: P<hir::Expr>) -> hir::Field {
1096 name: codemap::dummy_spanned(token::intern(field_name)),
1098 span: codemap::DUMMY_SP,
1102 // A range just desugars into a struct.
1103 // Note that the type of the start and end may not be the same, but
1104 // they should only differ in their lifetime, which should not matter
1106 let (did, fields, ty_params) = match (start, end) {
1107 (&Some(ref start), &Some(ref end)) => {
1109 let fields = vec![make_field("start", start.clone()),
1110 make_field("end", end.clone())];
1111 (tcx.lang_items.range_struct(), fields, vec![node_id_type(bcx, start.id)])
1113 (&Some(ref start), &None) => {
1114 // Desugar to RangeFrom
1115 let fields = vec![make_field("start", start.clone())];
1116 (tcx.lang_items.range_from_struct(), fields, vec![node_id_type(bcx, start.id)])
1118 (&None, &Some(ref end)) => {
1119 // Desugar to RangeTo
1120 let fields = vec![make_field("end", end.clone())];
1121 (tcx.lang_items.range_to_struct(), fields, vec![node_id_type(bcx, end.id)])
1124 // Desugar to RangeFull
1125 (tcx.lang_items.range_full_struct(), vec![], vec![])
1129 if let Some(did) = did {
1130 let substs = Substs::new_type(ty_params, vec![]);
1136 tcx.mk_struct(tcx.lookup_adt_def(did),
1137 tcx.mk_substs(substs)),
1140 tcx.sess.span_bug(expr.span,
1141 "No lang item for ranges (how did we get this far?)")
1144 hir::ExprTup(ref args) => {
1145 let numbered_fields: Vec<(usize, &hir::Expr)> =
1146 args.iter().enumerate().map(|(i, arg)| (i, &**arg)).collect();
1150 &numbered_fields[..],
1155 hir::ExprLit(ref lit) => {
1157 ast::LitKind::Str(ref s, _) => {
1158 tvec::trans_lit_str(bcx, expr, (*s).clone(), dest)
1163 .span_bug(expr.span,
1164 "trans_rvalue_dps_unadjusted shouldn't be \
1165 translating this type of literal")
1169 hir::ExprVec(..) | hir::ExprRepeat(..) => {
1170 tvec::trans_fixed_vstore(bcx, expr, dest)
1172 hir::ExprClosure(_, ref decl, ref body) => {
1173 let dest = match dest {
1174 SaveIn(lldest) => closure::Dest::SaveIn(bcx, lldest),
1175 Ignore => closure::Dest::Ignore(bcx.ccx())
1178 // NB. To get the id of the closure, we don't use
1179 // `local_def_id(id)`, but rather we extract the closure
1180 // def-id from the expr's type. This is because this may
1181 // be an inlined expression from another crate, and we
1182 // want to get the ORIGINAL closure def-id, since that is
1183 // the key we need to find the closure-kind and
1184 // closure-type etc.
1185 let (def_id, substs) = match expr_ty(bcx, expr).sty {
1186 ty::TyClosure(def_id, ref substs) => (def_id, substs),
1188 bcx.tcx().sess.span_bug(
1190 &format!("closure expr without closure type: {:?}", t)),
1193 closure::trans_closure_expr(dest,
1199 &expr.attrs).unwrap_or(bcx)
1201 hir::ExprCall(ref f, ref args) => {
1202 if bcx.tcx().is_method_call(expr.id) {
1203 trans_overloaded_call(bcx,
1209 callee::trans_call(bcx,
1212 callee::ArgExprs(&args[..]),
1216 hir::ExprMethodCall(_, _, ref args) => {
1217 callee::trans_method_call(bcx,
1220 callee::ArgExprs(&args[..]),
1223 hir::ExprBinary(op, ref lhs, ref rhs) => {
1224 // if not overloaded, would be RvalueDatumExpr
1225 let lhs = unpack_datum!(bcx, trans(bcx, &lhs));
1226 let rhs_datum = unpack_datum!(bcx, trans(bcx, &rhs));
1227 trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id), lhs,
1228 Some((rhs_datum, rhs.id)), Some(dest),
1229 !rustc_front::util::is_by_value_binop(op.node)).bcx
1231 hir::ExprUnary(op, ref subexpr) => {
1232 // if not overloaded, would be RvalueDatumExpr
1233 let arg = unpack_datum!(bcx, trans(bcx, &subexpr));
1234 trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id),
1235 arg, None, Some(dest), !rustc_front::util::is_by_value_unop(op)).bcx
1237 hir::ExprIndex(ref base, ref idx) => {
1238 // if not overloaded, would be RvalueDatumExpr
1239 let base = unpack_datum!(bcx, trans(bcx, &base));
1240 let idx_datum = unpack_datum!(bcx, trans(bcx, &idx));
1241 trans_overloaded_op(bcx, expr, MethodCall::expr(expr.id), base,
1242 Some((idx_datum, idx.id)), Some(dest), true).bcx
1244 hir::ExprCast(..) => {
1245 // Trait casts used to come this way, now they should be coercions.
1246 bcx.tcx().sess.span_bug(expr.span, "DPS expr_cast (residual trait cast?)")
1248 hir::ExprAssignOp(op, _, _) => {
1249 bcx.tcx().sess.span_bug(
1251 &format!("augmented assignment `{}=` should always be a rvalue_stmt",
1252 rustc_front::util::binop_to_string(op.node)))
1255 bcx.tcx().sess.span_bug(
1257 &format!("trans_rvalue_dps_unadjusted reached fall-through \
1264 fn trans_def_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1265 ref_expr: &hir::Expr,
1268 -> Block<'blk, 'tcx> {
1269 let _icx = push_ctxt("trans_def_dps_unadjusted");
1271 let lldest = match dest {
1272 SaveIn(lldest) => lldest,
1273 Ignore => { return bcx; }
1277 Def::Variant(tid, vid) => {
1278 let variant = bcx.tcx().lookup_adt_def(tid).variant_with_id(vid);
1279 if let ty::VariantKind::Tuple = variant.kind() {
1281 let llfn = callee::trans_fn_ref(bcx.ccx(), vid,
1282 ExprId(ref_expr.id),
1283 bcx.fcx.param_substs).val;
1284 Store(bcx, llfn, lldest);
1288 let ty = expr_ty(bcx, ref_expr);
1289 let repr = adt::represent_type(bcx.ccx(), ty);
1290 adt::trans_set_discr(bcx, &repr, lldest, Disr::from(variant.disr_val));
1294 Def::Struct(..) => {
1295 let ty = expr_ty(bcx, ref_expr);
1297 ty::TyStruct(def, _) if def.has_dtor() => {
1298 let repr = adt::represent_type(bcx.ccx(), ty);
1299 adt::trans_set_discr(bcx, &repr, lldest, Disr(0));
1306 bcx.tcx().sess.span_bug(ref_expr.span, &format!(
1307 "Non-DPS def {:?} referened by {}",
1308 def, bcx.node_id_to_string(ref_expr.id)));
1313 pub fn trans_def_fn_unadjusted<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1314 ref_expr: &hir::Expr,
1316 param_substs: &'tcx Substs<'tcx>)
1317 -> Datum<'tcx, Rvalue> {
1318 let _icx = push_ctxt("trans_def_datum_unadjusted");
1322 Def::Struct(did) | Def::Variant(_, did) => {
1323 callee::trans_fn_ref(ccx, did, ExprId(ref_expr.id), param_substs)
1325 Def::Method(method_did) => {
1326 match ccx.tcx().impl_or_trait_item(method_did).container() {
1327 ty::ImplContainer(_) => {
1328 callee::trans_fn_ref(ccx, method_did,
1329 ExprId(ref_expr.id),
1332 ty::TraitContainer(trait_did) => {
1333 meth::trans_static_method_callee(ccx, method_did,
1334 trait_did, ref_expr.id,
1340 ccx.tcx().sess.span_bug(ref_expr.span, &format!(
1341 "trans_def_fn_unadjusted invoked on: {:?} for {:?}",
1348 /// Translates a reference to a local variable or argument. This always results in an lvalue datum.
1349 pub fn trans_local_var<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1351 -> Datum<'tcx, Lvalue> {
1352 let _icx = push_ctxt("trans_local_var");
1355 Def::Upvar(_, nid, _, _) => {
1356 // Can't move upvars, so this is never a ZeroMemLastUse.
1357 let local_ty = node_id_type(bcx, nid);
1358 let lval = Lvalue::new_with_hint("expr::trans_local_var (upvar)",
1359 bcx, nid, HintKind::ZeroAndMaintain);
1360 match bcx.fcx.llupvars.borrow().get(&nid) {
1361 Some(&val) => Datum::new(val, local_ty, lval),
1363 bcx.sess().bug(&format!(
1364 "trans_local_var: no llval for upvar {} found",
1369 Def::Local(_, nid) => {
1370 let datum = match bcx.fcx.lllocals.borrow().get(&nid) {
1373 bcx.sess().bug(&format!(
1374 "trans_local_var: no datum for local/arg {} found",
1378 debug!("take_local(nid={}, v={}, ty={})",
1379 nid, bcx.val_to_string(datum.val), datum.ty);
1383 bcx.sess().unimpl(&format!(
1384 "unsupported def type in trans_local_var: {:?}",
1390 fn trans_struct<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1391 fields: &[hir::Field],
1392 base: Option<&hir::Expr>,
1393 expr_span: codemap::Span,
1394 expr_id: ast::NodeId,
1396 dest: Dest) -> Block<'blk, 'tcx> {
1397 let _icx = push_ctxt("trans_rec");
1399 let tcx = bcx.tcx();
1400 let vinfo = VariantInfo::of_node(tcx, ty, expr_id);
1402 let mut need_base = vec![true; vinfo.fields.len()];
1404 let numbered_fields = fields.iter().map(|field| {
1405 let pos = vinfo.field_index(field.name.node);
1406 need_base[pos] = false;
1408 }).collect::<Vec<_>>();
1410 let optbase = match base {
1411 Some(base_expr) => {
1412 let mut leftovers = Vec::new();
1413 for (i, b) in need_base.iter().enumerate() {
1415 leftovers.push((i, vinfo.fields[i].1));
1418 Some(StructBaseInfo {expr: base_expr,
1419 fields: leftovers })
1422 if need_base.iter().any(|b| *b) {
1423 tcx.sess.span_bug(expr_span, "missing fields and no base expr")
1435 DebugLoc::At(expr_id, expr_span))
1438 /// Information that `trans_adt` needs in order to fill in the fields
1439 /// of a struct copied from a base struct (e.g., from an expression
1440 /// like `Foo { a: b, ..base }`.
1442 /// Note that `fields` may be empty; the base expression must always be
1443 /// evaluated for side-effects.
1444 pub struct StructBaseInfo<'a, 'tcx> {
1445 /// The base expression; will be evaluated after all explicit fields.
1446 expr: &'a hir::Expr,
1447 /// The indices of fields to copy paired with their types.
1448 fields: Vec<(usize, Ty<'tcx>)>
1451 /// Constructs an ADT instance:
1453 /// - `fields` should be a list of field indices paired with the
1454 /// expression to store into that field. The initializers will be
1455 /// evaluated in the order specified by `fields`.
1457 /// - `optbase` contains information on the base struct (if any) from
1458 /// which remaining fields are copied; see comments on `StructBaseInfo`.
1459 pub fn trans_adt<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
1462 fields: &[(usize, &hir::Expr)],
1463 optbase: Option<StructBaseInfo<'a, 'tcx>>,
1465 debug_location: DebugLoc)
1466 -> Block<'blk, 'tcx> {
1467 let _icx = push_ctxt("trans_adt");
1469 let repr = adt::represent_type(bcx.ccx(), ty);
1471 debug_location.apply(bcx.fcx);
1473 // If we don't care about the result, just make a
1474 // temporary stack slot
1475 let addr = match dest {
1478 let llresult = alloc_ty(bcx, ty, "temp");
1479 call_lifetime_start(bcx, llresult);
1484 debug!("trans_adt");
1486 // This scope holds intermediates that must be cleaned should
1487 // panic occur before the ADT as a whole is ready.
1488 let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
1491 // Issue 23112: The original logic appeared vulnerable to same
1492 // order-of-eval bug. But, SIMD values are tuple-structs;
1493 // i.e. functional record update (FRU) syntax is unavailable.
1495 // To be safe, double-check that we did not get here via FRU.
1496 assert!(optbase.is_none());
1498 // This is the constructor of a SIMD type, such types are
1499 // always primitive machine types and so do not have a
1500 // destructor or require any clean-up.
1501 let llty = type_of::type_of(bcx.ccx(), ty);
1503 // keep a vector as a register, and running through the field
1504 // `insertelement`ing them directly into that register
1505 // (i.e. avoid GEPi and `store`s to an alloca) .
1506 let mut vec_val = C_undef(llty);
1508 for &(i, ref e) in fields {
1509 let block_datum = trans(bcx, &e);
1510 bcx = block_datum.bcx;
1511 let position = C_uint(bcx.ccx(), i);
1512 let value = block_datum.datum.to_llscalarish(bcx);
1513 vec_val = InsertElement(bcx, vec_val, value, position);
1515 Store(bcx, vec_val, addr);
1516 } else if let Some(base) = optbase {
1517 // Issue 23112: If there is a base, then order-of-eval
1518 // requires field expressions eval'ed before base expression.
1520 // First, trans field expressions to temporary scratch values.
1521 let scratch_vals: Vec<_> = fields.iter().map(|&(i, ref e)| {
1522 let datum = unpack_datum!(bcx, trans(bcx, &e));
1526 debug_location.apply(bcx.fcx);
1528 // Second, trans the base to the dest.
1529 assert_eq!(discr, Disr(0));
1531 let addr = adt::MaybeSizedValue::sized(addr);
1532 match expr_kind(bcx.tcx(), &base.expr) {
1533 ExprKind::RvalueDps | ExprKind::RvalueDatum if !bcx.fcx.type_needs_drop(ty) => {
1534 bcx = trans_into(bcx, &base.expr, SaveIn(addr.value));
1536 ExprKind::RvalueStmt => {
1537 bcx.tcx().sess.bug("unexpected expr kind for struct base expr")
1540 let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, &base.expr, "base"));
1541 for &(i, t) in &base.fields {
1542 let datum = base_datum.get_element(
1543 bcx, t, |srcval| adt::trans_field_ptr(bcx, &repr, srcval, discr, i));
1544 assert!(type_is_sized(bcx.tcx(), datum.ty));
1545 let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
1546 bcx = datum.store_to(bcx, dest);
1551 // Finally, move scratch field values into actual field locations
1552 for (i, datum) in scratch_vals {
1553 let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
1554 bcx = datum.store_to(bcx, dest);
1557 // No base means we can write all fields directly in place.
1558 let addr = adt::MaybeSizedValue::sized(addr);
1559 for &(i, ref e) in fields {
1560 let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
1561 let e_ty = expr_ty_adjusted(bcx, &e);
1562 bcx = trans_into(bcx, &e, SaveIn(dest));
1563 let scope = cleanup::CustomScope(custom_cleanup_scope);
1564 fcx.schedule_lifetime_end(scope, dest);
1565 // FIXME: nonzeroing move should generalize to fields
1566 fcx.schedule_drop_mem(scope, dest, e_ty, None);
1570 adt::trans_set_discr(bcx, &repr, addr, discr);
1572 fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
1574 // If we don't care about the result drop the temporary we made
1578 bcx = glue::drop_ty(bcx, addr, ty, debug_location);
1579 base::call_lifetime_end(bcx, addr);
1586 fn trans_immediate_lit<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1589 -> DatumBlock<'blk, 'tcx, Expr> {
1590 // must not be a string constant, that is a RvalueDpsExpr
1591 let _icx = push_ctxt("trans_immediate_lit");
1592 let ty = expr_ty(bcx, expr);
1593 let v = consts::const_lit(bcx.ccx(), expr, lit);
1594 immediate_rvalue_bcx(bcx, v, ty).to_expr_datumblock()
1597 fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1600 sub_expr: &hir::Expr)
1601 -> DatumBlock<'blk, 'tcx, Expr> {
1602 let ccx = bcx.ccx();
1604 let _icx = push_ctxt("trans_unary_datum");
1606 let method_call = MethodCall::expr(expr.id);
1608 // The only overloaded operator that is translated to a datum
1609 // is an overloaded deref, since it is always yields a `&T`.
1610 // Otherwise, we should be in the RvalueDpsExpr path.
1611 assert!(op == hir::UnDeref || !ccx.tcx().is_method_call(expr.id));
1613 let un_ty = expr_ty(bcx, expr);
1615 let debug_loc = expr.debug_loc();
1619 let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
1620 let llresult = Not(bcx, datum.to_llscalarish(bcx), debug_loc);
1621 immediate_rvalue_bcx(bcx, llresult, un_ty).to_expr_datumblock()
1624 let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
1625 let val = datum.to_llscalarish(bcx);
1626 let (bcx, llneg) = {
1628 let result = FNeg(bcx, val, debug_loc);
1631 let is_signed = un_ty.is_signed();
1632 let result = Neg(bcx, val, debug_loc);
1633 let bcx = if bcx.ccx().check_overflow() && is_signed {
1634 let (llty, min) = base::llty_and_min_for_signed_ty(bcx, un_ty);
1635 let is_min = ICmp(bcx, llvm::IntEQ, val,
1636 C_integral(llty, min, true), debug_loc);
1637 with_cond(bcx, is_min, |bcx| {
1638 let msg = InternedString::new(
1639 "attempted to negate with overflow");
1640 controlflow::trans_fail(bcx, expr_info(expr), msg)
1648 immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
1651 let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
1652 deref_once(bcx, expr, datum, method_call)
1657 fn trans_uniq_expr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1658 box_expr: &hir::Expr,
1660 contents: &hir::Expr,
1661 contents_ty: Ty<'tcx>)
1662 -> DatumBlock<'blk, 'tcx, Expr> {
1663 let _icx = push_ctxt("trans_uniq_expr");
1665 assert!(type_is_sized(bcx.tcx(), contents_ty));
1666 let llty = type_of::type_of(bcx.ccx(), contents_ty);
1667 let size = llsize_of(bcx.ccx(), llty);
1668 let align = C_uint(bcx.ccx(), type_of::align_of(bcx.ccx(), contents_ty));
1669 let llty_ptr = llty.ptr_to();
1670 let Result { bcx, val } = malloc_raw_dyn(bcx,
1675 box_expr.debug_loc());
1676 // Unique boxes do not allocate for zero-size types. The standard library
1677 // may assume that `free` is never called on the pointer returned for
1678 // `Box<ZeroSizeType>`.
1679 let bcx = if llsize_of_alloc(bcx.ccx(), llty) == 0 {
1680 trans_into(bcx, contents, SaveIn(val))
1682 let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
1683 fcx.schedule_free_value(cleanup::CustomScope(custom_cleanup_scope),
1684 val, cleanup::HeapExchange, contents_ty);
1685 let bcx = trans_into(bcx, contents, SaveIn(val));
1686 fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
1689 immediate_rvalue_bcx(bcx, val, box_ty).to_expr_datumblock()
1692 fn trans_addr_of<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1694 subexpr: &hir::Expr)
1695 -> DatumBlock<'blk, 'tcx, Expr> {
1696 let _icx = push_ctxt("trans_addr_of");
1698 let sub_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, subexpr, "addr_of"));
1699 let ty = expr_ty(bcx, expr);
1700 if !type_is_sized(bcx.tcx(), sub_datum.ty) {
1701 // Always generate an lvalue datum, because this pointer doesn't own
1702 // the data and cleanup is scheduled elsewhere.
1703 DatumBlock::new(bcx, Datum::new(sub_datum.val, ty, LvalueExpr(sub_datum.kind)))
1705 // Sized value, ref to a thin pointer
1706 immediate_rvalue_bcx(bcx, sub_datum.val, ty).to_expr_datumblock()
1710 fn trans_scalar_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1711 binop_expr: &hir::Expr,
1714 lhs: Datum<'tcx, Rvalue>,
1715 rhs: Datum<'tcx, Rvalue>)
1716 -> DatumBlock<'blk, 'tcx, Expr>
1718 let _icx = push_ctxt("trans_scalar_binop");
1720 let tcx = bcx.tcx();
1722 assert!(!lhs_t.is_simd());
1723 let is_float = lhs_t.is_fp();
1724 let is_signed = lhs_t.is_signed();
1725 let info = expr_info(binop_expr);
1727 let binop_debug_loc = binop_expr.debug_loc();
1730 let lhs = lhs.to_llscalarish(bcx);
1731 let rhs = rhs.to_llscalarish(bcx);
1732 let val = match op.node {
1735 FAdd(bcx, lhs, rhs, binop_debug_loc)
1737 let (newbcx, res) = with_overflow_check(
1738 bcx, OverflowOp::Add, info, lhs_t, lhs, rhs, binop_debug_loc);
1745 FSub(bcx, lhs, rhs, binop_debug_loc)
1747 let (newbcx, res) = with_overflow_check(
1748 bcx, OverflowOp::Sub, info, lhs_t, lhs, rhs, binop_debug_loc);
1755 FMul(bcx, lhs, rhs, binop_debug_loc)
1757 let (newbcx, res) = with_overflow_check(
1758 bcx, OverflowOp::Mul, info, lhs_t, lhs, rhs, binop_debug_loc);
1765 FDiv(bcx, lhs, rhs, binop_debug_loc)
1767 // Only zero-check integers; fp /0 is NaN
1768 bcx = base::fail_if_zero_or_overflows(bcx,
1769 expr_info(binop_expr),
1775 SDiv(bcx, lhs, rhs, binop_debug_loc)
1777 UDiv(bcx, lhs, rhs, binop_debug_loc)
1783 // LLVM currently always lowers the `frem` instructions appropriate
1784 // library calls typically found in libm. Notably f64 gets wired up
1785 // to `fmod` and f32 gets wired up to `fmodf`. Inconveniently for
1786 // us, 32-bit MSVC does not actually have a `fmodf` symbol, it's
1787 // instead just an inline function in a header that goes up to a
1788 // f64, uses `fmod`, and then comes back down to a f32.
1790 // Although LLVM knows that `fmodf` doesn't exist on MSVC, it will
1791 // still unconditionally lower frem instructions over 32-bit floats
1792 // to a call to `fmodf`. To work around this we special case MSVC
1793 // 32-bit float rem instructions and instead do the call out to
1794 // `fmod` ourselves.
1796 // Note that this is currently duplicated with src/libcore/ops.rs
1797 // which does the same thing, and it would be nice to perhaps unify
1798 // these two implementations on day! Also note that we call `fmod`
1799 // for both 32 and 64-bit floats because if we emit any FRem
1800 // instruction at all then LLVM is capable of optimizing it into a
1801 // 32-bit FRem (which we're trying to avoid).
1802 let use_fmod = tcx.sess.target.target.options.is_like_msvc &&
1803 tcx.sess.target.target.arch == "x86";
1805 let f64t = Type::f64(bcx.ccx());
1806 let fty = Type::func(&[f64t, f64t], &f64t);
1807 let llfn = declare::declare_cfn(bcx.ccx(), "fmod", fty,
1809 if lhs_t == tcx.types.f32 {
1810 let lhs = FPExt(bcx, lhs, f64t);
1811 let rhs = FPExt(bcx, rhs, f64t);
1812 let res = Call(bcx, llfn, &[lhs, rhs], None, binop_debug_loc);
1813 FPTrunc(bcx, res, Type::f32(bcx.ccx()))
1815 Call(bcx, llfn, &[lhs, rhs], None, binop_debug_loc)
1818 FRem(bcx, lhs, rhs, binop_debug_loc)
1821 // Only zero-check integers; fp %0 is NaN
1822 bcx = base::fail_if_zero_or_overflows(bcx,
1823 expr_info(binop_expr),
1824 op, lhs, rhs, lhs_t);
1826 SRem(bcx, lhs, rhs, binop_debug_loc)
1828 URem(bcx, lhs, rhs, binop_debug_loc)
1832 hir::BiBitOr => Or(bcx, lhs, rhs, binop_debug_loc),
1833 hir::BiBitAnd => And(bcx, lhs, rhs, binop_debug_loc),
1834 hir::BiBitXor => Xor(bcx, lhs, rhs, binop_debug_loc),
1836 let (newbcx, res) = with_overflow_check(
1837 bcx, OverflowOp::Shl, info, lhs_t, lhs, rhs, binop_debug_loc);
1842 let (newbcx, res) = with_overflow_check(
1843 bcx, OverflowOp::Shr, info, lhs_t, lhs, rhs, binop_debug_loc);
1847 hir::BiEq | hir::BiNe | hir::BiLt | hir::BiGe | hir::BiLe | hir::BiGt => {
1848 base::compare_scalar_types(bcx, lhs, rhs, lhs_t, op.node, binop_debug_loc)
1851 bcx.tcx().sess.span_bug(binop_expr.span, "unexpected binop");
1855 immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
1858 // refinement types would obviate the need for this
1859 enum lazy_binop_ty {
1864 fn trans_lazy_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1865 binop_expr: &hir::Expr,
1869 -> DatumBlock<'blk, 'tcx, Expr> {
1870 let _icx = push_ctxt("trans_lazy_binop");
1871 let binop_ty = expr_ty(bcx, binop_expr);
1874 let DatumBlock {bcx: past_lhs, datum: lhs} = trans(bcx, a);
1875 let lhs = lhs.to_llscalarish(past_lhs);
1877 if past_lhs.unreachable.get() {
1878 return immediate_rvalue_bcx(past_lhs, lhs, binop_ty).to_expr_datumblock();
1881 let join = fcx.new_id_block("join", binop_expr.id);
1882 let before_rhs = fcx.new_id_block("before_rhs", b.id);
1885 lazy_and => CondBr(past_lhs, lhs, before_rhs.llbb, join.llbb, DebugLoc::None),
1886 lazy_or => CondBr(past_lhs, lhs, join.llbb, before_rhs.llbb, DebugLoc::None)
1889 let DatumBlock {bcx: past_rhs, datum: rhs} = trans(before_rhs, b);
1890 let rhs = rhs.to_llscalarish(past_rhs);
1892 if past_rhs.unreachable.get() {
1893 return immediate_rvalue_bcx(join, lhs, binop_ty).to_expr_datumblock();
1896 Br(past_rhs, join.llbb, DebugLoc::None);
1897 let phi = Phi(join, Type::i1(bcx.ccx()), &[lhs, rhs],
1898 &[past_lhs.llbb, past_rhs.llbb]);
1900 return immediate_rvalue_bcx(join, phi, binop_ty).to_expr_datumblock();
1903 fn trans_binary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1908 -> DatumBlock<'blk, 'tcx, Expr> {
1909 let _icx = push_ctxt("trans_binary");
1910 let ccx = bcx.ccx();
1912 // if overloaded, would be RvalueDpsExpr
1913 assert!(!ccx.tcx().is_method_call(expr.id));
1917 trans_lazy_binop(bcx, expr, lazy_and, lhs, rhs)
1920 trans_lazy_binop(bcx, expr, lazy_or, lhs, rhs)
1924 let binop_ty = expr_ty(bcx, expr);
1926 let lhs = unpack_datum!(bcx, trans(bcx, lhs));
1927 let lhs = unpack_datum!(bcx, lhs.to_rvalue_datum(bcx, "binop_lhs"));
1928 debug!("trans_binary (expr {}): lhs={}",
1929 expr.id, lhs.to_string(ccx));
1930 let rhs = unpack_datum!(bcx, trans(bcx, rhs));
1931 let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "binop_rhs"));
1932 debug!("trans_binary (expr {}): rhs={}",
1933 expr.id, rhs.to_string(ccx));
1935 if type_is_fat_ptr(ccx.tcx(), lhs.ty) {
1936 assert!(type_is_fat_ptr(ccx.tcx(), rhs.ty),
1937 "built-in binary operators on fat pointers are homogeneous");
1938 assert_eq!(binop_ty, bcx.tcx().types.bool);
1939 let val = base::compare_scalar_types(
1946 immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
1948 assert!(!type_is_fat_ptr(ccx.tcx(), rhs.ty),
1949 "built-in binary operators on fat pointers are homogeneous");
1950 trans_scalar_binop(bcx, expr, binop_ty, op, lhs, rhs)
1956 fn trans_overloaded_op<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1958 method_call: MethodCall,
1959 lhs: Datum<'tcx, Expr>,
1960 rhs: Option<(Datum<'tcx, Expr>, ast::NodeId)>,
1963 -> Result<'blk, 'tcx> {
1964 callee::trans_call_inner(bcx,
1966 |bcx, arg_cleanup_scope| {
1967 meth::trans_method_callee(bcx,
1972 callee::ArgOverloadedOp(lhs, rhs, autoref),
1976 fn trans_overloaded_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
1978 callee: &'a hir::Expr,
1979 args: &'a [P<hir::Expr>],
1981 -> Block<'blk, 'tcx> {
1982 debug!("trans_overloaded_call {}", expr.id);
1983 let method_call = MethodCall::expr(expr.id);
1984 let mut all_args = vec!(callee);
1985 all_args.extend(args.iter().map(|e| &**e));
1987 callee::trans_call_inner(bcx,
1989 |bcx, arg_cleanup_scope| {
1990 meth::trans_method_callee(
1996 callee::ArgOverloadedCall(all_args),
2001 pub fn cast_is_noop<'tcx>(tcx: &TyCtxt<'tcx>,
2006 if let Some(&CastKind::CoercionCast) = tcx.cast_kinds.borrow().get(&expr.id) {
2010 match (t_in.builtin_deref(true, ty::NoPreference),
2011 t_out.builtin_deref(true, ty::NoPreference)) {
2012 (Some(ty::TypeAndMut{ ty: t_in, .. }), Some(ty::TypeAndMut{ ty: t_out, .. })) => {
2016 // This condition isn't redundant with the check for CoercionCast:
2017 // different types can be substituted into the same type, and
2018 // == equality can be overconservative if there are regions.
2024 fn trans_imm_cast<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2027 -> DatumBlock<'blk, 'tcx, Expr>
2029 use middle::ty::cast::CastTy::*;
2030 use middle::ty::cast::IntTy::*;
2032 fn int_cast(bcx: Block,
2039 let _icx = push_ctxt("int_cast");
2040 let srcsz = llsrctype.int_width();
2041 let dstsz = lldsttype.int_width();
2042 return if dstsz == srcsz {
2043 BitCast(bcx, llsrc, lldsttype)
2044 } else if srcsz > dstsz {
2045 TruncOrBitCast(bcx, llsrc, lldsttype)
2047 SExtOrBitCast(bcx, llsrc, lldsttype)
2049 ZExtOrBitCast(bcx, llsrc, lldsttype)
2053 fn float_cast(bcx: Block,
2059 let _icx = push_ctxt("float_cast");
2060 let srcsz = llsrctype.float_width();
2061 let dstsz = lldsttype.float_width();
2062 return if dstsz > srcsz {
2063 FPExt(bcx, llsrc, lldsttype)
2064 } else if srcsz > dstsz {
2065 FPTrunc(bcx, llsrc, lldsttype)
2069 let _icx = push_ctxt("trans_cast");
2071 let ccx = bcx.ccx();
2073 let t_in = expr_ty_adjusted(bcx, expr);
2074 let t_out = node_id_type(bcx, id);
2076 debug!("trans_cast({:?} as {:?})", t_in, t_out);
2077 let mut ll_t_in = type_of::arg_type_of(ccx, t_in);
2078 let ll_t_out = type_of::arg_type_of(ccx, t_out);
2079 // Convert the value to be cast into a ValueRef, either by-ref or
2080 // by-value as appropriate given its type:
2081 let mut datum = unpack_datum!(bcx, trans(bcx, expr));
2083 let datum_ty = monomorphize_type(bcx, datum.ty);
2085 if cast_is_noop(bcx.tcx(), expr, datum_ty, t_out) {
2087 return DatumBlock::new(bcx, datum);
2090 if type_is_fat_ptr(bcx.tcx(), t_in) {
2091 assert!(datum.kind.is_by_ref());
2092 if type_is_fat_ptr(bcx.tcx(), t_out) {
2093 return DatumBlock::new(bcx, Datum::new(
2094 PointerCast(bcx, datum.val, ll_t_out.ptr_to()),
2097 )).to_expr_datumblock();
2099 // Return the address
2100 return immediate_rvalue_bcx(bcx,
2102 Load(bcx, get_dataptr(bcx, datum.val)),
2104 t_out).to_expr_datumblock();
2108 let r_t_in = CastTy::from_ty(t_in).expect("bad input type for cast");
2109 let r_t_out = CastTy::from_ty(t_out).expect("bad output type for cast");
2111 let (llexpr, signed) = if let Int(CEnum) = r_t_in {
2112 let repr = adt::represent_type(ccx, t_in);
2113 let datum = unpack_datum!(
2114 bcx, datum.to_lvalue_datum(bcx, "trans_imm_cast", expr.id));
2115 let llexpr_ptr = datum.to_llref();
2116 let discr = adt::trans_get_discr(bcx, &repr, llexpr_ptr,
2117 Some(Type::i64(ccx)), true);
2118 ll_t_in = val_ty(discr);
2119 (discr, adt::is_discr_signed(&repr))
2121 (datum.to_llscalarish(bcx), t_in.is_signed())
2124 let newval = match (r_t_in, r_t_out) {
2125 (Ptr(_), Ptr(_)) | (FnPtr, Ptr(_)) | (RPtr(_), Ptr(_)) => {
2126 PointerCast(bcx, llexpr, ll_t_out)
2128 (Ptr(_), Int(_)) | (FnPtr, Int(_)) => PtrToInt(bcx, llexpr, ll_t_out),
2129 (Int(_), Ptr(_)) => IntToPtr(bcx, llexpr, ll_t_out),
2131 (Int(_), Int(_)) => int_cast(bcx, ll_t_out, ll_t_in, llexpr, signed),
2132 (Float, Float) => float_cast(bcx, ll_t_out, ll_t_in, llexpr),
2133 (Int(_), Float) if signed => SIToFP(bcx, llexpr, ll_t_out),
2134 (Int(_), Float) => UIToFP(bcx, llexpr, ll_t_out),
2135 (Float, Int(I)) => FPToSI(bcx, llexpr, ll_t_out),
2136 (Float, Int(_)) => FPToUI(bcx, llexpr, ll_t_out),
2138 _ => ccx.sess().span_bug(expr.span,
2139 &format!("translating unsupported cast: \
2145 return immediate_rvalue_bcx(bcx, newval, t_out).to_expr_datumblock();
2148 fn trans_assign_op<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2153 -> Block<'blk, 'tcx> {
2154 let _icx = push_ctxt("trans_assign_op");
2157 debug!("trans_assign_op(expr={:?})", expr);
2159 // User-defined operator methods cannot be used with `+=` etc right now
2160 assert!(!bcx.tcx().is_method_call(expr.id));
2162 // Evaluate LHS (destination), which should be an lvalue
2163 let dst = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
2164 assert!(!bcx.fcx.type_needs_drop(dst.ty));
2165 let lhs = load_ty(bcx, dst.val, dst.ty);
2166 let lhs = immediate_rvalue(lhs, dst.ty);
2168 // Evaluate RHS - FIXME(#28160) this sucks
2169 let rhs = unpack_datum!(bcx, trans(bcx, &src));
2170 let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "assign_op_rhs"));
2172 // Perform computation and store the result
2173 let result_datum = unpack_datum!(
2174 bcx, trans_scalar_binop(bcx, expr, dst.ty, op, lhs, rhs));
2175 return result_datum.store_to(bcx, dst.val);
2178 fn auto_ref<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2179 datum: Datum<'tcx, Expr>,
2181 -> DatumBlock<'blk, 'tcx, Expr> {
2184 // Ensure cleanup of `datum` if not already scheduled and obtain
2185 // a "by ref" pointer.
2186 let lv_datum = unpack_datum!(bcx, datum.to_lvalue_datum(bcx, "autoref", expr.id));
2188 // Compute final type. Note that we are loose with the region and
2189 // mutability, since those things don't matter in trans.
2190 let referent_ty = lv_datum.ty;
2191 let ptr_ty = bcx.tcx().mk_imm_ref(bcx.tcx().mk_region(ty::ReStatic), referent_ty);
2193 // Construct the resulting datum. The right datum to return here would be an Lvalue datum,
2194 // because there is cleanup scheduled and the datum doesn't own the data, but for thin pointers
2195 // we microoptimize it to be an Rvalue datum to avoid the extra alloca and level of
2196 // indirection and for thin pointers, this has no ill effects.
2197 let kind = if type_is_sized(bcx.tcx(), referent_ty) {
2198 RvalueExpr(Rvalue::new(ByValue))
2200 LvalueExpr(lv_datum.kind)
2204 let llref = lv_datum.to_llref();
2205 DatumBlock::new(bcx, Datum::new(llref, ptr_ty, kind))
2208 fn deref_multiple<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2210 datum: Datum<'tcx, Expr>,
2212 -> DatumBlock<'blk, 'tcx, Expr> {
2214 let mut datum = datum;
2216 let method_call = MethodCall::autoderef(expr.id, i as u32);
2217 datum = unpack_datum!(bcx, deref_once(bcx, expr, datum, method_call));
2219 DatumBlock { bcx: bcx, datum: datum }
2222 fn deref_once<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2224 datum: Datum<'tcx, Expr>,
2225 method_call: MethodCall)
2226 -> DatumBlock<'blk, 'tcx, Expr> {
2227 let ccx = bcx.ccx();
2229 debug!("deref_once(expr={:?}, datum={}, method_call={:?})",
2231 datum.to_string(ccx),
2236 // Check for overloaded deref.
2237 let method_ty = ccx.tcx()
2241 .get(&method_call).map(|method| method.ty);
2243 let datum = match method_ty {
2244 Some(method_ty) => {
2245 let method_ty = monomorphize_type(bcx, method_ty);
2247 // Overloaded. Evaluate `trans_overloaded_op`, which will
2248 // invoke the user's deref() method, which basically
2249 // converts from the `Smaht<T>` pointer that we have into
2250 // a `&T` pointer. We can then proceed down the normal
2251 // path (below) to dereference that `&T`.
2252 let datum = if method_call.autoderef == 0 {
2255 // Always perform an AutoPtr when applying an overloaded auto-deref
2256 unpack_datum!(bcx, auto_ref(bcx, datum, expr))
2259 let ref_ty = // invoked methods have their LB regions instantiated
2260 ccx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
2261 let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_deref");
2263 unpack_result!(bcx, trans_overloaded_op(bcx, expr, method_call,
2264 datum, None, Some(SaveIn(scratch.val)),
2266 scratch.to_expr_datum()
2269 // Not overloaded. We already have a pointer we know how to deref.
2274 let r = match datum.ty.sty {
2275 ty::TyBox(content_ty) => {
2276 // Make sure we have an lvalue datum here to get the
2277 // proper cleanups scheduled
2278 let datum = unpack_datum!(
2279 bcx, datum.to_lvalue_datum(bcx, "deref", expr.id));
2281 if type_is_sized(bcx.tcx(), content_ty) {
2282 let ptr = load_ty(bcx, datum.val, datum.ty);
2283 DatumBlock::new(bcx, Datum::new(ptr, content_ty, LvalueExpr(datum.kind)))
2285 // A fat pointer and a DST lvalue have the same representation
2286 // just different types. Since there is no temporary for `*e`
2287 // here (because it is unsized), we cannot emulate the sized
2288 // object code path for running drop glue and free. Instead,
2289 // we schedule cleanup for `e`, turning it into an lvalue.
2291 let lval = Lvalue::new("expr::deref_once ty_uniq");
2292 let datum = Datum::new(datum.val, content_ty, LvalueExpr(lval));
2293 DatumBlock::new(bcx, datum)
2297 ty::TyRawPtr(ty::TypeAndMut { ty: content_ty, .. }) |
2298 ty::TyRef(_, ty::TypeAndMut { ty: content_ty, .. }) => {
2299 let lval = Lvalue::new("expr::deref_once ptr");
2300 if type_is_sized(bcx.tcx(), content_ty) {
2301 let ptr = datum.to_llscalarish(bcx);
2303 // Always generate an lvalue datum, even if datum.mode is
2304 // an rvalue. This is because datum.mode is only an
2305 // rvalue for non-owning pointers like &T or *T, in which
2306 // case cleanup *is* scheduled elsewhere, by the true
2307 // owner (or, in the case of *T, by the user).
2308 DatumBlock::new(bcx, Datum::new(ptr, content_ty, LvalueExpr(lval)))
2310 // A fat pointer and a DST lvalue have the same representation
2311 // just different types.
2312 DatumBlock::new(bcx, Datum::new(datum.val, content_ty, LvalueExpr(lval)))
2317 bcx.tcx().sess.span_bug(
2319 &format!("deref invoked on expr of invalid type {:?}",
2324 debug!("deref_once(expr={}, method_call={:?}, result={})",
2325 expr.id, method_call, r.datum.to_string(ccx));
2340 fn codegen_strategy(&self) -> OverflowCodegen {
2341 use self::OverflowCodegen::{ViaIntrinsic, ViaInputCheck};
2343 OverflowOp::Add => ViaIntrinsic(OverflowOpViaIntrinsic::Add),
2344 OverflowOp::Sub => ViaIntrinsic(OverflowOpViaIntrinsic::Sub),
2345 OverflowOp::Mul => ViaIntrinsic(OverflowOpViaIntrinsic::Mul),
2347 OverflowOp::Shl => ViaInputCheck(OverflowOpViaInputCheck::Shl),
2348 OverflowOp::Shr => ViaInputCheck(OverflowOpViaInputCheck::Shr),
2353 enum OverflowCodegen {
2354 ViaIntrinsic(OverflowOpViaIntrinsic),
2355 ViaInputCheck(OverflowOpViaInputCheck),
2358 enum OverflowOpViaInputCheck { Shl, Shr, }
2361 enum OverflowOpViaIntrinsic { Add, Sub, Mul, }
2363 impl OverflowOpViaIntrinsic {
2364 fn to_intrinsic<'blk, 'tcx>(&self, bcx: Block<'blk, 'tcx>, lhs_ty: Ty) -> ValueRef {
2365 let name = self.to_intrinsic_name(bcx.tcx(), lhs_ty);
2366 bcx.ccx().get_intrinsic(&name)
2368 fn to_intrinsic_name(&self, tcx: &TyCtxt, ty: Ty) -> &'static str {
2369 use syntax::ast::IntTy::*;
2370 use syntax::ast::UintTy::*;
2371 use middle::ty::{TyInt, TyUint};
2373 let new_sty = match ty.sty {
2374 TyInt(Is) => match &tcx.sess.target.target.target_pointer_width[..] {
2377 _ => panic!("unsupported target word size")
2379 TyUint(Us) => match &tcx.sess.target.target.target_pointer_width[..] {
2380 "32" => TyUint(U32),
2381 "64" => TyUint(U64),
2382 _ => panic!("unsupported target word size")
2384 ref t @ TyUint(_) | ref t @ TyInt(_) => t.clone(),
2385 _ => panic!("tried to get overflow intrinsic for {:?} applied to non-int type",
2390 OverflowOpViaIntrinsic::Add => match new_sty {
2391 TyInt(I8) => "llvm.sadd.with.overflow.i8",
2392 TyInt(I16) => "llvm.sadd.with.overflow.i16",
2393 TyInt(I32) => "llvm.sadd.with.overflow.i32",
2394 TyInt(I64) => "llvm.sadd.with.overflow.i64",
2396 TyUint(U8) => "llvm.uadd.with.overflow.i8",
2397 TyUint(U16) => "llvm.uadd.with.overflow.i16",
2398 TyUint(U32) => "llvm.uadd.with.overflow.i32",
2399 TyUint(U64) => "llvm.uadd.with.overflow.i64",
2401 _ => unreachable!(),
2403 OverflowOpViaIntrinsic::Sub => match new_sty {
2404 TyInt(I8) => "llvm.ssub.with.overflow.i8",
2405 TyInt(I16) => "llvm.ssub.with.overflow.i16",
2406 TyInt(I32) => "llvm.ssub.with.overflow.i32",
2407 TyInt(I64) => "llvm.ssub.with.overflow.i64",
2409 TyUint(U8) => "llvm.usub.with.overflow.i8",
2410 TyUint(U16) => "llvm.usub.with.overflow.i16",
2411 TyUint(U32) => "llvm.usub.with.overflow.i32",
2412 TyUint(U64) => "llvm.usub.with.overflow.i64",
2414 _ => unreachable!(),
2416 OverflowOpViaIntrinsic::Mul => match new_sty {
2417 TyInt(I8) => "llvm.smul.with.overflow.i8",
2418 TyInt(I16) => "llvm.smul.with.overflow.i16",
2419 TyInt(I32) => "llvm.smul.with.overflow.i32",
2420 TyInt(I64) => "llvm.smul.with.overflow.i64",
2422 TyUint(U8) => "llvm.umul.with.overflow.i8",
2423 TyUint(U16) => "llvm.umul.with.overflow.i16",
2424 TyUint(U32) => "llvm.umul.with.overflow.i32",
2425 TyUint(U64) => "llvm.umul.with.overflow.i64",
2427 _ => unreachable!(),
2432 fn build_intrinsic_call<'blk, 'tcx>(&self, bcx: Block<'blk, 'tcx>,
2433 info: NodeIdAndSpan,
2434 lhs_t: Ty<'tcx>, lhs: ValueRef,
2436 binop_debug_loc: DebugLoc)
2437 -> (Block<'blk, 'tcx>, ValueRef) {
2438 let llfn = self.to_intrinsic(bcx, lhs_t);
2440 let val = Call(bcx, llfn, &[lhs, rhs], None, binop_debug_loc);
2441 let result = ExtractValue(bcx, val, 0); // iN operation result
2442 let overflow = ExtractValue(bcx, val, 1); // i1 "did it overflow?"
2444 let cond = ICmp(bcx, llvm::IntEQ, overflow, C_integral(Type::i1(bcx.ccx()), 1, false),
2447 let expect = bcx.ccx().get_intrinsic(&"llvm.expect.i1");
2448 Call(bcx, expect, &[cond, C_integral(Type::i1(bcx.ccx()), 0, false)],
2449 None, binop_debug_loc);
2452 base::with_cond(bcx, cond, |bcx|
2453 controlflow::trans_fail(bcx, info,
2454 InternedString::new("arithmetic operation overflowed")));
2460 impl OverflowOpViaInputCheck {
2461 fn build_with_input_check<'blk, 'tcx>(&self,
2462 bcx: Block<'blk, 'tcx>,
2463 info: NodeIdAndSpan,
2467 binop_debug_loc: DebugLoc)
2468 -> (Block<'blk, 'tcx>, ValueRef)
2470 let lhs_llty = val_ty(lhs);
2471 let rhs_llty = val_ty(rhs);
2473 // Panic if any bits are set outside of bits that we always
2476 // Note that the mask's value is derived from the LHS type
2477 // (since that is where the 32/64 distinction is relevant) but
2478 // the mask's type must match the RHS type (since they will
2479 // both be fed into an and-binop)
2480 let invert_mask = shift_mask_val(bcx, lhs_llty, rhs_llty, true);
2482 let outer_bits = And(bcx, rhs, invert_mask, binop_debug_loc);
2483 let cond = build_nonzero_check(bcx, outer_bits, binop_debug_loc);
2484 let result = match *self {
2485 OverflowOpViaInputCheck::Shl =>
2486 build_unchecked_lshift(bcx, lhs, rhs, binop_debug_loc),
2487 OverflowOpViaInputCheck::Shr =>
2488 build_unchecked_rshift(bcx, lhs_t, lhs, rhs, binop_debug_loc),
2491 base::with_cond(bcx, cond, |bcx|
2492 controlflow::trans_fail(bcx, info,
2493 InternedString::new("shift operation overflowed")));
2499 // Check if an integer or vector contains a nonzero element.
2500 fn build_nonzero_check<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2502 binop_debug_loc: DebugLoc) -> ValueRef {
2503 let llty = val_ty(value);
2504 let kind = llty.kind();
2506 TypeKind::Integer => ICmp(bcx, llvm::IntNE, value, C_null(llty), binop_debug_loc),
2507 TypeKind::Vector => {
2508 // Check if any elements of the vector are nonzero by treating
2509 // it as a wide integer and checking if the integer is nonzero.
2510 let width = llty.vector_length() as u64 * llty.element_type().int_width();
2511 let int_value = BitCast(bcx, value, Type::ix(bcx.ccx(), width));
2512 build_nonzero_check(bcx, int_value, binop_debug_loc)
2514 _ => panic!("build_nonzero_check: expected Integer or Vector, found {:?}", kind),
2518 fn with_overflow_check<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, oop: OverflowOp, info: NodeIdAndSpan,
2519 lhs_t: Ty<'tcx>, lhs: ValueRef,
2521 binop_debug_loc: DebugLoc)
2522 -> (Block<'blk, 'tcx>, ValueRef) {
2523 if bcx.unreachable.get() { return (bcx, _Undef(lhs)); }
2524 if bcx.ccx().check_overflow() {
2526 match oop.codegen_strategy() {
2527 OverflowCodegen::ViaIntrinsic(oop) =>
2528 oop.build_intrinsic_call(bcx, info, lhs_t, lhs, rhs, binop_debug_loc),
2529 OverflowCodegen::ViaInputCheck(oop) =>
2530 oop.build_with_input_check(bcx, info, lhs_t, lhs, rhs, binop_debug_loc),
2533 let res = match oop {
2534 OverflowOp::Add => Add(bcx, lhs, rhs, binop_debug_loc),
2535 OverflowOp::Sub => Sub(bcx, lhs, rhs, binop_debug_loc),
2536 OverflowOp::Mul => Mul(bcx, lhs, rhs, binop_debug_loc),
2539 build_unchecked_lshift(bcx, lhs, rhs, binop_debug_loc),
2541 build_unchecked_rshift(bcx, lhs_t, lhs, rhs, binop_debug_loc),
2547 /// We categorize expressions into three kinds. The distinction between
2548 /// lvalue/rvalue is fundamental to the language. The distinction between the
2549 /// two kinds of rvalues is an artifact of trans which reflects how we will
2550 /// generate code for that kind of expression. See trans/expr.rs for more
2552 #[derive(Copy, Clone)]
2560 fn expr_kind(tcx: &TyCtxt, expr: &hir::Expr) -> ExprKind {
2561 if tcx.is_method_call(expr.id) {
2562 // Overloaded operations are generally calls, and hence they are
2563 // generated via DPS, but there are a few exceptions:
2564 return match expr.node {
2565 // `a += b` has a unit result.
2566 hir::ExprAssignOp(..) => ExprKind::RvalueStmt,
2568 // the deref method invoked for `*a` always yields an `&T`
2569 hir::ExprUnary(hir::UnDeref, _) => ExprKind::Lvalue,
2571 // the index method invoked for `a[i]` always yields an `&T`
2572 hir::ExprIndex(..) => ExprKind::Lvalue,
2574 // in the general case, result could be any type, use DPS
2575 _ => ExprKind::RvalueDps
2580 hir::ExprPath(..) => {
2581 match tcx.resolve_expr(expr) {
2582 Def::Struct(..) | Def::Variant(..) => {
2583 if let ty::TyBareFn(..) = tcx.node_id_to_type(expr.id).sty {
2585 ExprKind::RvalueDatum
2591 // Fn pointers are just scalar values.
2592 Def::Fn(..) | Def::Method(..) => ExprKind::RvalueDatum,
2594 // Note: there is actually a good case to be made that
2595 // DefArg's, particularly those of immediate type, ought to
2596 // considered rvalues.
2599 Def::Local(..) => ExprKind::Lvalue,
2602 Def::AssociatedConst(..) => ExprKind::RvalueDatum,
2607 &format!("uncategorized def for expr {}: {:?}",
2614 hir::ExprType(ref expr, _) => {
2615 expr_kind(tcx, expr)
2618 hir::ExprUnary(hir::UnDeref, _) |
2619 hir::ExprField(..) |
2620 hir::ExprTupField(..) |
2621 hir::ExprIndex(..) => {
2626 hir::ExprMethodCall(..) |
2627 hir::ExprStruct(..) |
2628 hir::ExprRange(..) |
2631 hir::ExprMatch(..) |
2632 hir::ExprClosure(..) |
2633 hir::ExprBlock(..) |
2634 hir::ExprRepeat(..) |
2635 hir::ExprVec(..) => {
2639 hir::ExprLit(ref lit) if lit.node.is_str() => {
2643 hir::ExprBreak(..) |
2644 hir::ExprAgain(..) |
2646 hir::ExprWhile(..) |
2648 hir::ExprAssign(..) |
2649 hir::ExprInlineAsm(..) |
2650 hir::ExprAssignOp(..) => {
2651 ExprKind::RvalueStmt
2654 hir::ExprLit(_) | // Note: LitStr is carved out above
2655 hir::ExprUnary(..) |
2657 hir::ExprAddrOf(..) |
2658 hir::ExprBinary(..) |
2659 hir::ExprCast(..) => {
2660 ExprKind::RvalueDatum