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_var -> Datum`: looks up a local variable, upvar or static.
49 #![allow(non_camel_case_types)]
51 pub use self::Dest::*;
52 use self::lazy_binop_ty::*;
54 use llvm::{self, ValueRef, TypeKind};
55 use middle::const_qualif::ConstQualif;
56 use rustc::hir::def::Def;
57 use rustc::ty::subst::Substs;
58 use {_match, abi, adt, asm, base, closure, consts, controlflow};
61 use callee::{Callee, ArgExprs, ArgOverloadedCall, ArgOverloadedOp};
62 use cleanup::{self, CleanupMethods, DropHintMethods};
65 use debuginfo::{self, DebugLoc, ToDebugLoc};
72 use rustc::ty::adjustment::{AdjustDerefRef, AdjustReifyFnPointer};
73 use rustc::ty::adjustment::{AdjustUnsafeFnPointer, AdjustMutToConstPointer};
74 use rustc::ty::adjustment::CustomCoerceUnsized;
75 use rustc::ty::{self, Ty, TyCtxt};
76 use rustc::ty::MethodCall;
77 use rustc::ty::cast::{CastKind, CastTy};
78 use util::common::indenter;
79 use machine::{llsize_of, llsize_of_alloc};
85 use syntax::parse::token::InternedString;
92 // These are passed around by the code generating functions to track the
93 // destination of a computation's value.
95 #[derive(Copy, Clone, PartialEq)]
101 impl fmt::Debug for Dest {
102 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
104 SaveIn(v) => write!(f, "SaveIn({:?})", Value(v)),
105 Ignore => f.write_str("Ignore")
110 /// This function is equivalent to `trans(bcx, expr).store_to_dest(dest)` but it may generate
111 /// better optimized LLVM code.
112 pub fn trans_into<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
115 -> Block<'blk, 'tcx> {
118 expr.debug_loc().apply(bcx.fcx);
120 if adjustment_required(bcx, expr) {
121 // use trans, which may be less efficient but
122 // which will perform the adjustments:
123 let datum = unpack_datum!(bcx, trans(bcx, expr));
124 return datum.store_to_dest(bcx, dest, expr.id);
127 let qualif = *bcx.tcx().const_qualif_map.borrow().get(&expr.id).unwrap();
128 if !qualif.intersects(ConstQualif::NOT_CONST | ConstQualif::NEEDS_DROP) {
129 if !qualif.intersects(ConstQualif::PREFER_IN_PLACE) {
130 if let SaveIn(lldest) = dest {
131 match consts::get_const_expr_as_global(bcx.ccx(), expr, qualif,
132 bcx.fcx.param_substs,
133 consts::TrueConst::No) {
135 // Cast pointer to destination, because constants
136 // have different types.
137 let lldest = PointerCast(bcx, lldest, val_ty(global));
138 memcpy_ty(bcx, lldest, global, expr_ty_adjusted(bcx, expr));
141 Err(consts::ConstEvalFailure::Runtime(_)) => {
142 // in case const evaluation errors, translate normally
143 // debug assertions catch the same errors
146 Err(consts::ConstEvalFailure::Compiletime(_)) => {
152 // If we see a const here, that's because it evaluates to a type with zero size. We
153 // should be able to just discard it, since const expressions are guaranteed not to
154 // have side effects. This seems to be reached through tuple struct constructors being
155 // passed zero-size constants.
156 if let hir::ExprPath(..) = expr.node {
157 match bcx.tcx().expect_def(expr.id) {
158 Def::Const(_) | Def::AssociatedConst(_) => {
159 assert!(type_is_zero_size(bcx.ccx(), bcx.tcx().node_id_to_type(expr.id)));
166 // Even if we don't have a value to emit, and the expression
167 // doesn't have any side-effects, we still have to translate the
168 // body of any closures.
169 // FIXME: Find a better way of handling this case.
171 // The only way we're going to see a `const` at this point is if
172 // it prefers in-place instantiation, likely because it contains
173 // `[x; N]` somewhere within.
175 hir::ExprPath(..) => {
176 match bcx.tcx().expect_def(expr.id) {
177 Def::Const(did) | Def::AssociatedConst(did) => {
178 let empty_substs = bcx.tcx().mk_substs(Substs::empty());
179 let const_expr = consts::get_const_expr(bcx.ccx(), did, expr,
181 // Temporarily get cleanup scopes out of the way,
182 // as they require sub-expressions to be contained
183 // inside the current AST scope.
184 // These should record no cleanups anyways, `const`
185 // can't have destructors.
186 let scopes = mem::replace(&mut *bcx.fcx.scopes.borrow_mut(),
188 // Lock emitted debug locations to the location of
189 // the constant reference expression.
190 debuginfo::with_source_location_override(bcx.fcx,
193 bcx = trans_into(bcx, const_expr, dest)
195 let scopes = mem::replace(&mut *bcx.fcx.scopes.borrow_mut(),
197 assert!(scopes.is_empty());
208 debug!("trans_into() expr={:?}", expr);
210 let cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
214 bcx.fcx.push_ast_cleanup_scope(cleanup_debug_loc);
216 let kind = expr_kind(bcx.tcx(), expr);
218 ExprKind::Lvalue | ExprKind::RvalueDatum => {
219 trans_unadjusted(bcx, expr).store_to_dest(dest, expr.id)
221 ExprKind::RvalueDps => {
222 trans_rvalue_dps_unadjusted(bcx, expr, dest)
224 ExprKind::RvalueStmt => {
225 trans_rvalue_stmt_unadjusted(bcx, expr)
229 bcx.fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id)
232 /// Translates an expression, returning a datum (and new block) encapsulating the result. When
233 /// possible, it is preferred to use `trans_into`, as that may avoid creating a temporary on the
235 pub fn trans<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
237 -> DatumBlock<'blk, 'tcx, Expr> {
238 debug!("trans(expr={:?})", expr);
242 let qualif = *bcx.tcx().const_qualif_map.borrow().get(&expr.id).unwrap();
243 let adjusted_global = !qualif.intersects(ConstQualif::NON_STATIC_BORROWS);
244 let global = if !qualif.intersects(ConstQualif::NOT_CONST | ConstQualif::NEEDS_DROP) {
245 match consts::get_const_expr_as_global(bcx.ccx(), expr, qualif,
246 bcx.fcx.param_substs,
247 consts::TrueConst::No) {
249 if qualif.intersects(ConstQualif::HAS_STATIC_BORROWS) {
250 // Is borrowed as 'static, must return lvalue.
252 // Cast pointer to global, because constants have different types.
253 let const_ty = expr_ty_adjusted(bcx, expr);
254 let llty = type_of::type_of(bcx.ccx(), const_ty);
255 let global = PointerCast(bcx, global, llty.ptr_to());
256 let datum = Datum::new(global, const_ty, Lvalue::new("expr::trans"));
257 return DatumBlock::new(bcx, datum.to_expr_datum());
260 // Otherwise, keep around and perform adjustments, if needed.
261 let const_ty = if adjusted_global {
262 expr_ty_adjusted(bcx, expr)
267 // This could use a better heuristic.
268 Some(if type_is_immediate(bcx.ccx(), const_ty) {
269 // Cast pointer to global, because constants have different types.
270 let llty = type_of::type_of(bcx.ccx(), const_ty);
271 let global = PointerCast(bcx, global, llty.ptr_to());
272 // Maybe just get the value directly, instead of loading it?
273 immediate_rvalue(load_ty(bcx, global, const_ty), const_ty)
275 let scratch = alloc_ty(bcx, const_ty, "const");
276 call_lifetime_start(bcx, scratch);
277 let lldest = if !const_ty.is_structural() {
278 // Cast pointer to slot, because constants have different types.
279 PointerCast(bcx, scratch, val_ty(global))
281 // In this case, memcpy_ty calls llvm.memcpy after casting both
282 // source and destination to i8*, so we don't need any casts.
285 memcpy_ty(bcx, lldest, global, const_ty);
286 Datum::new(scratch, const_ty, Rvalue::new(ByRef))
289 Err(consts::ConstEvalFailure::Runtime(_)) => {
290 // in case const evaluation errors, translate normally
291 // debug assertions catch the same errors
295 Err(consts::ConstEvalFailure::Compiletime(_)) => {
296 // generate a dummy llvm value
297 let const_ty = expr_ty(bcx, expr);
298 let llty = type_of::type_of(bcx.ccx(), const_ty);
299 let dummy = C_undef(llty.ptr_to());
300 Some(Datum::new(dummy, const_ty, Rvalue::new(ByRef)))
307 let cleanup_debug_loc = debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
311 fcx.push_ast_cleanup_scope(cleanup_debug_loc);
312 let datum = match global {
313 Some(rvalue) => rvalue.to_expr_datum(),
314 None => unpack_datum!(bcx, trans_unadjusted(bcx, expr))
316 let datum = if adjusted_global {
317 datum // trans::consts already performed adjustments.
319 unpack_datum!(bcx, apply_adjustments(bcx, expr, datum))
321 bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, expr.id);
322 return DatumBlock::new(bcx, datum);
325 pub fn get_meta(bcx: Block, fat_ptr: ValueRef) -> ValueRef {
326 StructGEP(bcx, fat_ptr, abi::FAT_PTR_EXTRA)
329 pub fn get_dataptr(bcx: Block, fat_ptr: ValueRef) -> ValueRef {
330 StructGEP(bcx, fat_ptr, abi::FAT_PTR_ADDR)
333 pub fn copy_fat_ptr(bcx: Block, src_ptr: ValueRef, dst_ptr: ValueRef) {
334 Store(bcx, Load(bcx, get_dataptr(bcx, src_ptr)), get_dataptr(bcx, dst_ptr));
335 Store(bcx, Load(bcx, get_meta(bcx, src_ptr)), get_meta(bcx, dst_ptr));
338 fn adjustment_required<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
339 expr: &hir::Expr) -> bool {
340 let adjustment = match bcx.tcx().tables.borrow().adjustments.get(&expr.id).cloned() {
341 None => { return false; }
345 // Don't skip a conversion from Box<T> to &T, etc.
346 if bcx.tcx().is_overloaded_autoderef(expr.id, 0) {
351 AdjustReifyFnPointer => true,
352 AdjustUnsafeFnPointer | AdjustMutToConstPointer => {
353 // purely a type-level thing
356 AdjustDerefRef(ref adj) => {
357 // We are a bit paranoid about adjustments and thus might have a re-
358 // borrow here which merely derefs and then refs again (it might have
359 // a different region or mutability, but we don't care here).
360 !(adj.autoderefs == 1 && adj.autoref.is_some() && adj.unsize.is_none())
365 /// Helper for trans that apply adjustments from `expr` to `datum`, which should be the unadjusted
366 /// translation of `expr`.
367 fn apply_adjustments<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
369 datum: Datum<'tcx, Expr>)
370 -> DatumBlock<'blk, 'tcx, Expr>
373 let mut datum = datum;
374 let adjustment = match bcx.tcx().tables.borrow().adjustments.get(&expr.id).cloned() {
376 return DatumBlock::new(bcx, datum);
380 debug!("unadjusted datum for expr {:?}: {:?} adjustment={:?}",
381 expr, datum, adjustment);
383 AdjustReifyFnPointer => {
385 ty::TyFnDef(def_id, substs, _) => {
386 datum = Callee::def(bcx.ccx(), def_id, substs)
387 .reify(bcx.ccx()).to_expr_datum();
390 bug!("{} cannot be reified to a fn ptr", datum.ty)
394 AdjustUnsafeFnPointer | AdjustMutToConstPointer => {
395 // purely a type-level thing
397 AdjustDerefRef(ref adj) => {
398 let skip_reborrows = if adj.autoderefs == 1 && adj.autoref.is_some() {
399 // We are a bit paranoid about adjustments and thus might have a re-
400 // borrow here which merely derefs and then refs again (it might have
401 // a different region or mutability, but we don't care here).
403 // Don't skip a conversion from Box<T> to &T, etc.
405 if bcx.tcx().is_overloaded_autoderef(expr.id, 0) {
406 // Don't skip an overloaded deref.
418 if adj.autoderefs > skip_reborrows {
420 let lval = unpack_datum!(bcx, datum.to_lvalue_datum(bcx, "auto_deref", expr.id));
421 datum = unpack_datum!(bcx, deref_multiple(bcx, expr,
422 lval.to_expr_datum(),
423 adj.autoderefs - skip_reborrows));
426 // (You might think there is a more elegant way to do this than a
427 // skip_reborrows bool, but then you remember that the borrow checker exists).
428 if skip_reborrows == 0 && adj.autoref.is_some() {
429 datum = unpack_datum!(bcx, auto_ref(bcx, datum, expr));
432 if let Some(target) = adj.unsize {
433 // We do not arrange cleanup ourselves; if we already are an
434 // L-value, then cleanup will have already been scheduled (and
435 // the `datum.to_rvalue_datum` call below will emit code to zero
436 // the drop flag when moving out of the L-value). If we are an
437 // R-value, then we do not need to schedule cleanup.
438 let source_datum = unpack_datum!(bcx,
439 datum.to_rvalue_datum(bcx, "__coerce_source"));
441 let target = bcx.monomorphize(&target);
443 let scratch = alloc_ty(bcx, target, "__coerce_target");
444 call_lifetime_start(bcx, scratch);
445 let target_datum = Datum::new(scratch, target,
447 bcx = coerce_unsized(bcx, expr.span, source_datum, target_datum);
448 datum = Datum::new(scratch, target,
449 RvalueExpr(Rvalue::new(ByRef)));
453 debug!("after adjustments, datum={:?}", datum);
454 DatumBlock::new(bcx, datum)
457 fn coerce_unsized<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
458 span: syntax_pos::Span,
459 source: Datum<'tcx, Rvalue>,
460 target: Datum<'tcx, Rvalue>)
461 -> Block<'blk, 'tcx> {
463 debug!("coerce_unsized({:?} -> {:?})", source, target);
465 match (&source.ty.sty, &target.ty.sty) {
466 (&ty::TyBox(a), &ty::TyBox(b)) |
467 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
468 &ty::TyRef(_, ty::TypeAndMut { ty: b, .. })) |
469 (&ty::TyRef(_, ty::TypeAndMut { ty: a, .. }),
470 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) |
471 (&ty::TyRawPtr(ty::TypeAndMut { ty: a, .. }),
472 &ty::TyRawPtr(ty::TypeAndMut { ty: b, .. })) => {
473 let (inner_source, inner_target) = (a, b);
475 let (base, old_info) = if !type_is_sized(bcx.tcx(), inner_source) {
476 // Normally, the source is a thin pointer and we are
477 // adding extra info to make a fat pointer. The exception
478 // is when we are upcasting an existing object fat pointer
479 // to use a different vtable. In that case, we want to
480 // load out the original data pointer so we can repackage
482 (Load(bcx, get_dataptr(bcx, source.val)),
483 Some(Load(bcx, get_meta(bcx, source.val))))
485 let val = if source.kind.is_by_ref() {
486 load_ty(bcx, source.val, source.ty)
493 let info = unsized_info(bcx.ccx(), inner_source, inner_target, old_info);
495 // Compute the base pointer. This doesn't change the pointer value,
496 // but merely its type.
497 let ptr_ty = type_of::in_memory_type_of(bcx.ccx(), inner_target).ptr_to();
498 let base = PointerCast(bcx, base, ptr_ty);
500 Store(bcx, base, get_dataptr(bcx, target.val));
501 Store(bcx, info, get_meta(bcx, target.val));
504 // This can be extended to enums and tuples in the future.
505 // (&ty::TyEnum(def_id_a, _), &ty::TyEnum(def_id_b, _)) |
506 (&ty::TyStruct(def_id_a, _), &ty::TyStruct(def_id_b, _)) => {
507 assert_eq!(def_id_a, def_id_b);
509 // The target is already by-ref because it's to be written to.
510 let source = unpack_datum!(bcx, source.to_ref_datum(bcx));
511 assert!(target.kind.is_by_ref());
513 let kind = custom_coerce_unsize_info(bcx.ccx().shared(),
517 let repr_source = adt::represent_type(bcx.ccx(), source.ty);
518 let src_fields = match &*repr_source {
519 &adt::Repr::Univariant(ref s, _) => &s.fields,
521 "Non univariant struct? (repr_source: {:?})",
524 let repr_target = adt::represent_type(bcx.ccx(), target.ty);
525 let target_fields = match &*repr_target {
526 &adt::Repr::Univariant(ref s, _) => &s.fields,
528 "Non univariant struct? (repr_target: {:?})",
532 let coerce_index = match kind {
533 CustomCoerceUnsized::Struct(i) => i
535 assert!(coerce_index < src_fields.len() && src_fields.len() == target_fields.len());
537 let source_val = adt::MaybeSizedValue::sized(source.val);
538 let target_val = adt::MaybeSizedValue::sized(target.val);
540 let iter = src_fields.iter().zip(target_fields).enumerate();
541 for (i, (src_ty, target_ty)) in iter {
542 let ll_source = adt::trans_field_ptr(bcx, &repr_source, source_val, Disr(0), i);
543 let ll_target = adt::trans_field_ptr(bcx, &repr_target, target_val, Disr(0), i);
545 // If this is the field we need to coerce, recurse on it.
546 if i == coerce_index {
547 coerce_unsized(bcx, span,
548 Datum::new(ll_source, src_ty,
550 Datum::new(ll_target, target_ty,
551 Rvalue::new(ByRef)));
553 // Otherwise, simply copy the data from the source.
554 assert!(src_ty.is_phantom_data() || src_ty == target_ty);
555 memcpy_ty(bcx, ll_target, ll_source, src_ty);
559 _ => bug!("coerce_unsized: invalid coercion {:?} -> {:?}",
566 /// Translates an expression in "lvalue" mode -- meaning that it returns a reference to the memory
567 /// that the expr represents.
569 /// If this expression is an rvalue, this implies introducing a temporary. In other words,
570 /// something like `x().f` is translated into roughly the equivalent of
572 /// { tmp = x(); tmp.f }
573 pub fn trans_to_lvalue<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
576 -> DatumBlock<'blk, 'tcx, Lvalue> {
578 let datum = unpack_datum!(bcx, trans(bcx, expr));
579 return datum.to_lvalue_datum(bcx, name, expr.id);
582 /// A version of `trans` that ignores adjustments. You almost certainly do not want to call this
584 fn trans_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
586 -> DatumBlock<'blk, 'tcx, Expr> {
589 debug!("trans_unadjusted(expr={:?})", expr);
590 let _indenter = indenter();
592 expr.debug_loc().apply(bcx.fcx);
594 return match expr_kind(bcx.tcx(), expr) {
595 ExprKind::Lvalue | ExprKind::RvalueDatum => {
596 let datum = unpack_datum!(bcx, {
597 trans_datum_unadjusted(bcx, expr)
600 DatumBlock {bcx: bcx, datum: datum}
603 ExprKind::RvalueStmt => {
604 bcx = trans_rvalue_stmt_unadjusted(bcx, expr);
605 nil(bcx, expr_ty(bcx, expr))
608 ExprKind::RvalueDps => {
609 let ty = expr_ty(bcx, expr);
610 if type_is_zero_size(bcx.ccx(), ty) {
611 bcx = trans_rvalue_dps_unadjusted(bcx, expr, Ignore);
614 let scratch = rvalue_scratch_datum(bcx, ty, "");
615 bcx = trans_rvalue_dps_unadjusted(
616 bcx, expr, SaveIn(scratch.val));
618 // Note: this is not obviously a good idea. It causes
619 // immediate values to be loaded immediately after a
620 // return from a call or other similar expression,
621 // which in turn leads to alloca's having shorter
622 // lifetimes and hence larger stack frames. However,
623 // in turn it can lead to more register pressure.
624 // Still, in practice it seems to increase
625 // performance, since we have fewer problems with
627 let scratch = unpack_datum!(
628 bcx, scratch.to_appropriate_datum(bcx));
630 DatumBlock::new(bcx, scratch.to_expr_datum())
635 fn nil<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, ty: Ty<'tcx>)
636 -> DatumBlock<'blk, 'tcx, Expr> {
637 let llval = C_undef(type_of::type_of(bcx.ccx(), ty));
638 let datum = immediate_rvalue(llval, ty);
639 DatumBlock::new(bcx, datum.to_expr_datum())
643 fn trans_datum_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
645 -> DatumBlock<'blk, 'tcx, Expr> {
648 let _icx = push_ctxt("trans_datum_unadjusted");
651 hir::ExprType(ref e, _) => {
654 hir::ExprPath(..) => {
655 let var = trans_var(bcx, bcx.tcx().expect_def(expr.id));
656 DatumBlock::new(bcx, var.to_expr_datum())
658 hir::ExprField(ref base, name) => {
659 trans_rec_field(bcx, &base, name.node)
661 hir::ExprTupField(ref base, idx) => {
662 trans_rec_tup_field(bcx, &base, idx.node)
664 hir::ExprIndex(ref base, ref idx) => {
665 trans_index(bcx, expr, &base, &idx, MethodCall::expr(expr.id))
667 hir::ExprBox(ref contents) => {
668 // Special case for `Box<T>`
669 let box_ty = expr_ty(bcx, expr);
670 let contents_ty = expr_ty(bcx, &contents);
673 trans_uniq_expr(bcx, expr, box_ty, &contents, contents_ty)
675 _ => span_bug!(expr.span,
676 "expected unique box")
680 hir::ExprLit(ref lit) => trans_immediate_lit(bcx, expr, &lit),
681 hir::ExprBinary(op, ref lhs, ref rhs) => {
682 trans_binary(bcx, expr, op, &lhs, &rhs)
684 hir::ExprUnary(op, ref x) => {
685 trans_unary(bcx, expr, op, &x)
687 hir::ExprAddrOf(_, ref x) => {
689 hir::ExprRepeat(..) | hir::ExprVec(..) => {
690 // Special case for slices.
691 let cleanup_debug_loc =
692 debuginfo::get_cleanup_debug_loc_for_ast_node(bcx.ccx(),
696 fcx.push_ast_cleanup_scope(cleanup_debug_loc);
697 let datum = unpack_datum!(
698 bcx, tvec::trans_slice_vec(bcx, expr, &x));
699 bcx = fcx.pop_and_trans_ast_cleanup_scope(bcx, x.id);
700 DatumBlock::new(bcx, datum)
703 trans_addr_of(bcx, expr, &x)
707 hir::ExprCast(ref val, _) => {
708 // Datum output mode means this is a scalar cast:
709 trans_imm_cast(bcx, &val, expr.id)
714 "trans_rvalue_datum_unadjusted reached \
715 fall-through case: {:?}",
721 fn trans_field<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>,
724 -> DatumBlock<'blk, 'tcx, Expr> where
725 F: FnOnce(TyCtxt<'blk, 'tcx, 'tcx>, &VariantInfo<'tcx>) -> usize,
728 let _icx = push_ctxt("trans_rec_field");
730 let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, base, "field"));
731 let bare_ty = base_datum.ty;
732 let repr = adt::represent_type(bcx.ccx(), bare_ty);
733 let vinfo = VariantInfo::from_ty(bcx.tcx(), bare_ty, None);
735 let ix = get_idx(bcx.tcx(), &vinfo);
736 let d = base_datum.get_element(
740 adt::trans_field_ptr(bcx, &repr, srcval, vinfo.discr, ix)
743 if type_is_sized(bcx.tcx(), d.ty) {
744 DatumBlock { datum: d.to_expr_datum(), bcx: bcx }
746 let scratch = rvalue_scratch_datum(bcx, d.ty, "");
747 Store(bcx, d.val, get_dataptr(bcx, scratch.val));
748 let info = Load(bcx, get_meta(bcx, base_datum.val));
749 Store(bcx, info, get_meta(bcx, scratch.val));
751 // Always generate an lvalue datum, because this pointer doesn't own
752 // the data and cleanup is scheduled elsewhere.
753 DatumBlock::new(bcx, Datum::new(scratch.val, scratch.ty, LvalueExpr(d.kind)))
757 /// Translates `base.field`.
758 fn trans_rec_field<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
761 -> DatumBlock<'blk, 'tcx, Expr> {
762 trans_field(bcx, base, |_, vinfo| vinfo.field_index(field))
765 /// Translates `base.<idx>`.
766 fn trans_rec_tup_field<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
769 -> DatumBlock<'blk, 'tcx, Expr> {
770 trans_field(bcx, base, |_, _| idx)
773 fn trans_index<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
774 index_expr: &hir::Expr,
777 method_call: MethodCall)
778 -> DatumBlock<'blk, 'tcx, Expr> {
779 //! Translates `base[idx]`.
781 let _icx = push_ctxt("trans_index");
785 let index_expr_debug_loc = index_expr.debug_loc();
787 // Check for overloaded index.
788 let method = ccx.tcx().tables.borrow().method_map.get(&method_call).cloned();
789 let elt_datum = match method {
791 let method_ty = monomorphize_type(bcx, method.ty);
793 let base_datum = unpack_datum!(bcx, trans(bcx, base));
795 // Translate index expression.
796 let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
798 let ref_ty = // invoked methods have LB regions instantiated:
799 bcx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
800 let elt_ty = match ref_ty.builtin_deref(true, ty::NoPreference) {
802 span_bug!(index_expr.span,
803 "index method didn't return a \
804 dereferenceable type?!")
806 Some(elt_tm) => elt_tm.ty,
809 // Overloaded. Invoke the index() method, which basically
810 // yields a `&T` pointer. We can then proceed down the
811 // normal path (below) to dereference that `&T`.
812 let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_index_elt");
814 bcx = Callee::method(bcx, method)
815 .call(bcx, index_expr_debug_loc,
816 ArgOverloadedOp(base_datum, Some(ix_datum)),
817 Some(SaveIn(scratch.val))).bcx;
819 let datum = scratch.to_expr_datum();
820 let lval = Lvalue::new("expr::trans_index overload");
821 if type_is_sized(bcx.tcx(), elt_ty) {
822 Datum::new(datum.to_llscalarish(bcx), elt_ty, LvalueExpr(lval))
824 Datum::new(datum.val, elt_ty, LvalueExpr(lval))
828 let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx,
832 // Translate index expression and cast to a suitable LLVM integer.
833 // Rust is less strict than LLVM in this regard.
834 let ix_datum = unpack_datum!(bcx, trans(bcx, idx));
835 let ix_val = ix_datum.to_llscalarish(bcx);
836 let ix_size = machine::llbitsize_of_real(bcx.ccx(),
838 let int_size = machine::llbitsize_of_real(bcx.ccx(),
841 if ix_size < int_size {
842 if expr_ty(bcx, idx).is_signed() {
843 SExt(bcx, ix_val, ccx.int_type())
844 } else { ZExt(bcx, ix_val, ccx.int_type()) }
845 } else if ix_size > int_size {
846 Trunc(bcx, ix_val, ccx.int_type())
852 let unit_ty = base_datum.ty.sequence_element_type(bcx.tcx());
854 let (base, len) = base_datum.get_vec_base_and_len(bcx);
856 debug!("trans_index: base {:?}", Value(base));
857 debug!("trans_index: len {:?}", Value(len));
859 let bounds_check = ICmp(bcx,
863 index_expr_debug_loc);
864 let expect = ccx.get_intrinsic(&("llvm.expect.i1"));
865 let expected = Call(bcx,
867 &[bounds_check, C_bool(ccx, false)],
868 index_expr_debug_loc);
869 bcx = with_cond(bcx, expected, |bcx| {
870 controlflow::trans_fail_bounds_check(bcx,
871 expr_info(index_expr),
875 let elt = InBoundsGEP(bcx, base, &[ix_val]);
876 let elt = PointerCast(bcx, elt, type_of::type_of(ccx, unit_ty).ptr_to());
877 let lval = Lvalue::new("expr::trans_index fallback");
878 Datum::new(elt, unit_ty, LvalueExpr(lval))
882 DatumBlock::new(bcx, elt_datum)
885 /// Translates a reference to a variable.
886 pub fn trans_var<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, def: Def)
887 -> Datum<'tcx, Lvalue> {
890 Def::Static(did, _) => consts::get_static(bcx.ccx(), did),
891 Def::Upvar(_, nid, _, _) => {
892 // Can't move upvars, so this is never a ZeroMemLastUse.
893 let local_ty = node_id_type(bcx, nid);
894 let lval = Lvalue::new_with_hint("expr::trans_var (upvar)",
895 bcx, nid, HintKind::ZeroAndMaintain);
896 match bcx.fcx.llupvars.borrow().get(&nid) {
897 Some(&val) => Datum::new(val, local_ty, lval),
899 bug!("trans_var: no llval for upvar {} found", nid);
903 Def::Local(_, nid) => {
904 let datum = match bcx.fcx.lllocals.borrow().get(&nid) {
907 bug!("trans_var: no datum for local/arg {} found", nid);
910 debug!("take_local(nid={}, v={:?}, ty={})",
911 nid, Value(datum.val), datum.ty);
914 _ => bug!("{:?} should not reach expr::trans_var", def)
918 fn trans_rvalue_stmt_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
920 -> Block<'blk, 'tcx> {
922 let _icx = push_ctxt("trans_rvalue_stmt");
924 if bcx.unreachable.get() {
928 expr.debug_loc().apply(bcx.fcx);
931 hir::ExprBreak(label_opt) => {
932 controlflow::trans_break(bcx, expr, label_opt.map(|l| l.node))
934 hir::ExprType(ref e, _) => {
935 trans_into(bcx, &e, Ignore)
937 hir::ExprAgain(label_opt) => {
938 controlflow::trans_cont(bcx, expr, label_opt.map(|l| l.node))
940 hir::ExprRet(ref ex) => {
941 // Check to see if the return expression itself is reachable.
942 // This can occur when the inner expression contains a return
943 let reachable = if let Some(ref cfg) = bcx.fcx.cfg {
944 cfg.node_is_reachable(expr.id)
950 controlflow::trans_ret(bcx, expr, ex.as_ref().map(|e| &**e))
952 // If it's not reachable, just translate the inner expression
953 // directly. This avoids having to manage a return slot when
954 // it won't actually be used anyway.
955 if let &Some(ref x) = ex {
956 bcx = trans_into(bcx, &x, Ignore);
958 // Mark the end of the block as unreachable. Once we get to
959 // a return expression, there's no more we should be doing
965 hir::ExprWhile(ref cond, ref body, _) => {
966 controlflow::trans_while(bcx, expr, &cond, &body)
968 hir::ExprLoop(ref body, _) => {
969 controlflow::trans_loop(bcx, expr, &body)
971 hir::ExprAssign(ref dst, ref src) => {
972 let src_datum = unpack_datum!(bcx, trans(bcx, &src));
973 let dst_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, &dst, "assign"));
975 if bcx.fcx.type_needs_drop(dst_datum.ty) {
976 // If there are destructors involved, make sure we
977 // are copying from an rvalue, since that cannot possible
978 // alias an lvalue. We are concerned about code like:
986 // where e.g. a : Option<Foo> and a.b :
987 // Option<Foo>. In that case, freeing `a` before the
988 // assignment may also free `a.b`!
990 // We could avoid this intermediary with some analysis
991 // to determine whether `dst` may possibly own `src`.
992 expr.debug_loc().apply(bcx.fcx);
993 let src_datum = unpack_datum!(
994 bcx, src_datum.to_rvalue_datum(bcx, "ExprAssign"));
995 let opt_hint_datum = dst_datum.kind.drop_flag_info.hint_datum(bcx);
996 let opt_hint_val = opt_hint_datum.map(|d|d.to_value());
998 // 1. Drop the data at the destination, passing the
999 // drop-hint in case the lvalue has already been
1000 // dropped or moved.
1001 bcx = glue::drop_ty_core(bcx,
1008 // 2. We are overwriting the destination; ensure that
1009 // its drop-hint (if any) says "initialized."
1010 if let Some(hint_val) = opt_hint_val {
1011 let hint_llval = hint_val.value();
1012 let drop_needed = C_u8(bcx.fcx.ccx, adt::DTOR_NEEDED_HINT);
1013 Store(bcx, drop_needed, hint_llval);
1015 src_datum.store_to(bcx, dst_datum.val)
1017 src_datum.store_to(bcx, dst_datum.val)
1020 hir::ExprAssignOp(op, ref dst, ref src) => {
1021 let method = bcx.tcx().tables
1024 .get(&MethodCall::expr(expr.id)).cloned();
1026 if let Some(method) = method {
1027 let dst = unpack_datum!(bcx, trans(bcx, &dst));
1028 let src_datum = unpack_datum!(bcx, trans(bcx, &src));
1030 Callee::method(bcx, method)
1031 .call(bcx, expr.debug_loc(),
1032 ArgOverloadedOp(dst, Some(src_datum)), None).bcx
1034 trans_assign_op(bcx, expr, op, &dst, &src)
1037 hir::ExprInlineAsm(ref a, ref outputs, ref inputs) => {
1038 let outputs = outputs.iter().map(|output| {
1039 let out_datum = unpack_datum!(bcx, trans(bcx, output));
1040 unpack_datum!(bcx, out_datum.to_lvalue_datum(bcx, "out", expr.id))
1042 let inputs = inputs.iter().map(|input| {
1043 let input = unpack_datum!(bcx, trans(bcx, input));
1044 let input = unpack_datum!(bcx, input.to_rvalue_datum(bcx, "in"));
1045 input.to_llscalarish(bcx)
1047 asm::trans_inline_asm(bcx, a, outputs, inputs);
1053 "trans_rvalue_stmt_unadjusted reached \
1054 fall-through case: {:?}",
1060 fn trans_rvalue_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1063 -> Block<'blk, 'tcx> {
1064 let _icx = push_ctxt("trans_rvalue_dps_unadjusted");
1067 expr.debug_loc().apply(bcx.fcx);
1069 // Entry into the method table if this is an overloaded call/op.
1070 let method_call = MethodCall::expr(expr.id);
1073 hir::ExprType(ref e, _) => {
1074 trans_into(bcx, &e, dest)
1076 hir::ExprPath(..) => {
1077 trans_def_dps_unadjusted(bcx, expr, bcx.tcx().expect_def(expr.id), dest)
1079 hir::ExprIf(ref cond, ref thn, ref els) => {
1080 controlflow::trans_if(bcx, expr.id, &cond, &thn, els.as_ref().map(|e| &**e), dest)
1082 hir::ExprMatch(ref discr, ref arms, _) => {
1083 _match::trans_match(bcx, expr, &discr, &arms[..], dest)
1085 hir::ExprBlock(ref blk) => {
1086 controlflow::trans_block(bcx, &blk, dest)
1088 hir::ExprStruct(_, ref fields, ref base) => {
1091 base.as_ref().map(|e| &**e),
1094 node_id_type(bcx, expr.id),
1097 hir::ExprTup(ref args) => {
1098 let numbered_fields: Vec<(usize, &hir::Expr)> =
1099 args.iter().enumerate().map(|(i, arg)| (i, &**arg)).collect();
1103 &numbered_fields[..],
1108 hir::ExprLit(ref lit) => {
1110 ast::LitKind::Str(ref s, _) => {
1111 tvec::trans_lit_str(bcx, expr, (*s).clone(), dest)
1114 span_bug!(expr.span,
1115 "trans_rvalue_dps_unadjusted shouldn't be \
1116 translating this type of literal")
1120 hir::ExprVec(..) | hir::ExprRepeat(..) => {
1121 tvec::trans_fixed_vstore(bcx, expr, dest)
1123 hir::ExprClosure(_, ref decl, ref body, _) => {
1124 let dest = match dest {
1125 SaveIn(lldest) => closure::Dest::SaveIn(bcx, lldest),
1126 Ignore => closure::Dest::Ignore(bcx.ccx())
1129 // NB. To get the id of the closure, we don't use
1130 // `local_def_id(id)`, but rather we extract the closure
1131 // def-id from the expr's type. This is because this may
1132 // be an inlined expression from another crate, and we
1133 // want to get the ORIGINAL closure def-id, since that is
1134 // the key we need to find the closure-kind and
1135 // closure-type etc.
1136 let (def_id, substs) = match expr_ty(bcx, expr).sty {
1137 ty::TyClosure(def_id, substs) => (def_id, substs),
1141 "closure expr without closure type: {:?}", t),
1144 closure::trans_closure_expr(dest,
1149 substs).unwrap_or(bcx)
1151 hir::ExprCall(ref f, ref args) => {
1152 let method = bcx.tcx().tables.borrow().method_map.get(&method_call).cloned();
1153 let (callee, args) = if let Some(method) = method {
1154 let mut all_args = vec![&**f];
1155 all_args.extend(args.iter().map(|e| &**e));
1157 (Callee::method(bcx, method), ArgOverloadedCall(all_args))
1159 let f = unpack_datum!(bcx, trans(bcx, f));
1161 ty::TyFnDef(def_id, substs, _) => {
1162 Callee::def(bcx.ccx(), def_id, substs)
1165 let f = unpack_datum!(bcx,
1166 f.to_rvalue_datum(bcx, "callee"));
1170 span_bug!(expr.span,
1171 "type of callee is not a fn: {}", f.ty);
1175 callee.call(bcx, expr.debug_loc(), args, Some(dest)).bcx
1177 hir::ExprMethodCall(_, _, ref args) => {
1178 Callee::method_call(bcx, method_call)
1179 .call(bcx, expr.debug_loc(), ArgExprs(&args), Some(dest)).bcx
1181 hir::ExprBinary(op, ref lhs, ref rhs_expr) => {
1182 // if not overloaded, would be RvalueDatumExpr
1183 let lhs = unpack_datum!(bcx, trans(bcx, &lhs));
1184 let mut rhs = unpack_datum!(bcx, trans(bcx, &rhs_expr));
1185 if !op.node.is_by_value() {
1186 rhs = unpack_datum!(bcx, auto_ref(bcx, rhs, rhs_expr));
1189 Callee::method_call(bcx, method_call)
1190 .call(bcx, expr.debug_loc(),
1191 ArgOverloadedOp(lhs, Some(rhs)), Some(dest)).bcx
1193 hir::ExprUnary(_, ref subexpr) => {
1194 // if not overloaded, would be RvalueDatumExpr
1195 let arg = unpack_datum!(bcx, trans(bcx, &subexpr));
1197 Callee::method_call(bcx, method_call)
1198 .call(bcx, expr.debug_loc(),
1199 ArgOverloadedOp(arg, None), Some(dest)).bcx
1201 hir::ExprCast(..) => {
1202 // Trait casts used to come this way, now they should be coercions.
1203 span_bug!(expr.span, "DPS expr_cast (residual trait cast?)")
1205 hir::ExprAssignOp(op, _, _) => {
1208 "augmented assignment `{}=` should always be a rvalue_stmt",
1214 "trans_rvalue_dps_unadjusted reached fall-through \
1221 fn trans_def_dps_unadjusted<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1222 ref_expr: &hir::Expr,
1225 -> Block<'blk, 'tcx> {
1226 let _icx = push_ctxt("trans_def_dps_unadjusted");
1228 let lldest = match dest {
1229 SaveIn(lldest) => lldest,
1230 Ignore => { return bcx; }
1233 let ty = expr_ty(bcx, ref_expr);
1234 if let ty::TyFnDef(..) = ty.sty {
1235 // Zero-sized function or ctor.
1240 Def::Variant(tid, vid) => {
1241 let variant = bcx.tcx().lookup_adt_def(tid).variant_with_id(vid);
1243 let ty = expr_ty(bcx, ref_expr);
1244 let repr = adt::represent_type(bcx.ccx(), ty);
1245 adt::trans_set_discr(bcx, &repr, lldest, Disr::from(variant.disr_val));
1248 Def::Struct(..) => {
1250 ty::TyStruct(def, _) if def.has_dtor() => {
1251 let repr = adt::represent_type(bcx.ccx(), ty);
1252 adt::trans_set_discr(bcx, &repr, lldest, Disr(0));
1259 span_bug!(ref_expr.span,
1260 "Non-DPS def {:?} referened by {}",
1261 def, bcx.node_id_to_string(ref_expr.id));
1266 fn trans_struct<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1267 fields: &[hir::Field],
1268 base: Option<&hir::Expr>,
1269 expr_span: syntax_pos::Span,
1270 expr_id: ast::NodeId,
1272 dest: Dest) -> Block<'blk, 'tcx> {
1273 let _icx = push_ctxt("trans_rec");
1275 let tcx = bcx.tcx();
1276 let vinfo = VariantInfo::of_node(tcx, ty, expr_id);
1278 let mut need_base = vec![true; vinfo.fields.len()];
1280 let numbered_fields = fields.iter().map(|field| {
1281 let pos = vinfo.field_index(field.name.node);
1282 need_base[pos] = false;
1284 }).collect::<Vec<_>>();
1286 let optbase = match base {
1287 Some(base_expr) => {
1288 let mut leftovers = Vec::new();
1289 for (i, b) in need_base.iter().enumerate() {
1291 leftovers.push((i, vinfo.fields[i].1));
1294 Some(StructBaseInfo {expr: base_expr,
1295 fields: leftovers })
1298 if need_base.iter().any(|b| *b) {
1299 span_bug!(expr_span, "missing fields and no base expr")
1311 DebugLoc::At(expr_id, expr_span))
1314 /// Information that `trans_adt` needs in order to fill in the fields
1315 /// of a struct copied from a base struct (e.g., from an expression
1316 /// like `Foo { a: b, ..base }`.
1318 /// Note that `fields` may be empty; the base expression must always be
1319 /// evaluated for side-effects.
1320 pub struct StructBaseInfo<'a, 'tcx> {
1321 /// The base expression; will be evaluated after all explicit fields.
1322 expr: &'a hir::Expr,
1323 /// The indices of fields to copy paired with their types.
1324 fields: Vec<(usize, Ty<'tcx>)>
1327 /// Constructs an ADT instance:
1329 /// - `fields` should be a list of field indices paired with the
1330 /// expression to store into that field. The initializers will be
1331 /// evaluated in the order specified by `fields`.
1333 /// - `optbase` contains information on the base struct (if any) from
1334 /// which remaining fields are copied; see comments on `StructBaseInfo`.
1335 pub fn trans_adt<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
1338 fields: &[(usize, &hir::Expr)],
1339 optbase: Option<StructBaseInfo<'a, 'tcx>>,
1341 debug_location: DebugLoc)
1342 -> Block<'blk, 'tcx> {
1343 let _icx = push_ctxt("trans_adt");
1345 let repr = adt::represent_type(bcx.ccx(), ty);
1347 debug_location.apply(bcx.fcx);
1349 // If we don't care about the result, just make a
1350 // temporary stack slot
1351 let addr = match dest {
1354 let llresult = alloc_ty(bcx, ty, "temp");
1355 call_lifetime_start(bcx, llresult);
1360 debug!("trans_adt");
1362 // This scope holds intermediates that must be cleaned should
1363 // panic occur before the ADT as a whole is ready.
1364 let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
1367 // Issue 23112: The original logic appeared vulnerable to same
1368 // order-of-eval bug. But, SIMD values are tuple-structs;
1369 // i.e. functional record update (FRU) syntax is unavailable.
1371 // To be safe, double-check that we did not get here via FRU.
1372 assert!(optbase.is_none());
1374 // This is the constructor of a SIMD type, such types are
1375 // always primitive machine types and so do not have a
1376 // destructor or require any clean-up.
1377 let llty = type_of::type_of(bcx.ccx(), ty);
1379 // keep a vector as a register, and running through the field
1380 // `insertelement`ing them directly into that register
1381 // (i.e. avoid GEPi and `store`s to an alloca) .
1382 let mut vec_val = C_undef(llty);
1384 for &(i, ref e) in fields {
1385 let block_datum = trans(bcx, &e);
1386 bcx = block_datum.bcx;
1387 let position = C_uint(bcx.ccx(), i);
1388 let value = block_datum.datum.to_llscalarish(bcx);
1389 vec_val = InsertElement(bcx, vec_val, value, position);
1391 Store(bcx, vec_val, addr);
1392 } else if let Some(base) = optbase {
1393 // Issue 23112: If there is a base, then order-of-eval
1394 // requires field expressions eval'ed before base expression.
1396 // First, trans field expressions to temporary scratch values.
1397 let scratch_vals: Vec<_> = fields.iter().map(|&(i, ref e)| {
1398 let datum = unpack_datum!(bcx, trans(bcx, &e));
1402 debug_location.apply(bcx.fcx);
1404 // Second, trans the base to the dest.
1405 assert_eq!(discr, Disr(0));
1407 let addr = adt::MaybeSizedValue::sized(addr);
1408 match expr_kind(bcx.tcx(), &base.expr) {
1409 ExprKind::RvalueDps | ExprKind::RvalueDatum if !bcx.fcx.type_needs_drop(ty) => {
1410 bcx = trans_into(bcx, &base.expr, SaveIn(addr.value));
1412 ExprKind::RvalueStmt => {
1413 bug!("unexpected expr kind for struct base expr")
1416 let base_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, &base.expr, "base"));
1417 for &(i, t) in &base.fields {
1418 let datum = base_datum.get_element(
1419 bcx, t, |srcval| adt::trans_field_ptr(bcx, &repr, srcval, discr, i));
1420 assert!(type_is_sized(bcx.tcx(), datum.ty));
1421 let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
1422 bcx = datum.store_to(bcx, dest);
1427 // Finally, move scratch field values into actual field locations
1428 for (i, datum) in scratch_vals {
1429 let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
1430 bcx = datum.store_to(bcx, dest);
1433 // No base means we can write all fields directly in place.
1434 let addr = adt::MaybeSizedValue::sized(addr);
1435 for &(i, ref e) in fields {
1436 let dest = adt::trans_field_ptr(bcx, &repr, addr, discr, i);
1437 let e_ty = expr_ty_adjusted(bcx, &e);
1438 bcx = trans_into(bcx, &e, SaveIn(dest));
1439 let scope = cleanup::CustomScope(custom_cleanup_scope);
1440 fcx.schedule_lifetime_end(scope, dest);
1441 // FIXME: nonzeroing move should generalize to fields
1442 fcx.schedule_drop_mem(scope, dest, e_ty, None);
1446 adt::trans_set_discr(bcx, &repr, addr, discr);
1448 fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
1450 // If we don't care about the result drop the temporary we made
1454 bcx = glue::drop_ty(bcx, addr, ty, debug_location);
1455 base::call_lifetime_end(bcx, addr);
1462 fn trans_immediate_lit<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1465 -> DatumBlock<'blk, 'tcx, Expr> {
1466 // must not be a string constant, that is a RvalueDpsExpr
1467 let _icx = push_ctxt("trans_immediate_lit");
1468 let ty = expr_ty(bcx, expr);
1469 let v = consts::const_lit(bcx.ccx(), expr, lit);
1470 immediate_rvalue_bcx(bcx, v, ty).to_expr_datumblock()
1473 fn trans_unary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1476 sub_expr: &hir::Expr)
1477 -> DatumBlock<'blk, 'tcx, Expr> {
1478 let ccx = bcx.ccx();
1480 let _icx = push_ctxt("trans_unary_datum");
1482 let method_call = MethodCall::expr(expr.id);
1484 // The only overloaded operator that is translated to a datum
1485 // is an overloaded deref, since it is always yields a `&T`.
1486 // Otherwise, we should be in the RvalueDpsExpr path.
1487 assert!(op == hir::UnDeref || !ccx.tcx().is_method_call(expr.id));
1489 let un_ty = expr_ty(bcx, expr);
1491 let debug_loc = expr.debug_loc();
1495 let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
1496 let llresult = Not(bcx, datum.to_llscalarish(bcx), debug_loc);
1497 immediate_rvalue_bcx(bcx, llresult, un_ty).to_expr_datumblock()
1500 let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
1501 let val = datum.to_llscalarish(bcx);
1502 let (bcx, llneg) = {
1504 let result = FNeg(bcx, val, debug_loc);
1507 let is_signed = un_ty.is_signed();
1508 let result = Neg(bcx, val, debug_loc);
1509 let bcx = if bcx.ccx().check_overflow() && is_signed {
1510 let (llty, min) = base::llty_and_min_for_signed_ty(bcx, un_ty);
1511 let is_min = ICmp(bcx, llvm::IntEQ, val,
1512 C_integral(llty, min, true), debug_loc);
1513 with_cond(bcx, is_min, |bcx| {
1514 let msg = InternedString::new(
1515 "attempted to negate with overflow");
1516 controlflow::trans_fail(bcx, expr_info(expr), msg)
1524 immediate_rvalue_bcx(bcx, llneg, un_ty).to_expr_datumblock()
1527 let datum = unpack_datum!(bcx, trans(bcx, sub_expr));
1528 deref_once(bcx, expr, datum, method_call)
1533 fn trans_uniq_expr<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1534 box_expr: &hir::Expr,
1536 contents: &hir::Expr,
1537 contents_ty: Ty<'tcx>)
1538 -> DatumBlock<'blk, 'tcx, Expr> {
1539 let _icx = push_ctxt("trans_uniq_expr");
1541 assert!(type_is_sized(bcx.tcx(), contents_ty));
1542 let llty = type_of::type_of(bcx.ccx(), contents_ty);
1543 let size = llsize_of(bcx.ccx(), llty);
1544 let align = C_uint(bcx.ccx(), type_of::align_of(bcx.ccx(), contents_ty));
1545 let llty_ptr = llty.ptr_to();
1546 let Result { bcx, val } = malloc_raw_dyn(bcx,
1551 box_expr.debug_loc());
1552 // Unique boxes do not allocate for zero-size types. The standard library
1553 // may assume that `free` is never called on the pointer returned for
1554 // `Box<ZeroSizeType>`.
1555 let bcx = if llsize_of_alloc(bcx.ccx(), llty) == 0 {
1556 trans_into(bcx, contents, SaveIn(val))
1558 let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
1559 fcx.schedule_free_value(cleanup::CustomScope(custom_cleanup_scope),
1560 val, cleanup::HeapExchange, contents_ty);
1561 let bcx = trans_into(bcx, contents, SaveIn(val));
1562 fcx.pop_custom_cleanup_scope(custom_cleanup_scope);
1565 immediate_rvalue_bcx(bcx, val, box_ty).to_expr_datumblock()
1568 fn trans_addr_of<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1570 subexpr: &hir::Expr)
1571 -> DatumBlock<'blk, 'tcx, Expr> {
1572 let _icx = push_ctxt("trans_addr_of");
1574 let sub_datum = unpack_datum!(bcx, trans_to_lvalue(bcx, subexpr, "addr_of"));
1575 let ty = expr_ty(bcx, expr);
1576 if !type_is_sized(bcx.tcx(), sub_datum.ty) {
1577 // Always generate an lvalue datum, because this pointer doesn't own
1578 // the data and cleanup is scheduled elsewhere.
1579 DatumBlock::new(bcx, Datum::new(sub_datum.val, ty, LvalueExpr(sub_datum.kind)))
1581 // Sized value, ref to a thin pointer
1582 immediate_rvalue_bcx(bcx, sub_datum.val, ty).to_expr_datumblock()
1586 fn trans_scalar_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1587 binop_expr: &hir::Expr,
1590 lhs: Datum<'tcx, Rvalue>,
1591 rhs: Datum<'tcx, Rvalue>)
1592 -> DatumBlock<'blk, 'tcx, Expr>
1594 let _icx = push_ctxt("trans_scalar_binop");
1597 assert!(!lhs_t.is_simd());
1598 let is_float = lhs_t.is_fp();
1599 let is_signed = lhs_t.is_signed();
1600 let info = expr_info(binop_expr);
1602 let binop_debug_loc = binop_expr.debug_loc();
1605 let lhs = lhs.to_llscalarish(bcx);
1606 let rhs = rhs.to_llscalarish(bcx);
1607 let val = match op.node {
1610 FAdd(bcx, lhs, rhs, binop_debug_loc)
1612 let (newbcx, res) = with_overflow_check(
1613 bcx, OverflowOp::Add, info, lhs_t, lhs, rhs, binop_debug_loc);
1620 FSub(bcx, lhs, rhs, binop_debug_loc)
1622 let (newbcx, res) = with_overflow_check(
1623 bcx, OverflowOp::Sub, info, lhs_t, lhs, rhs, binop_debug_loc);
1630 FMul(bcx, lhs, rhs, binop_debug_loc)
1632 let (newbcx, res) = with_overflow_check(
1633 bcx, OverflowOp::Mul, info, lhs_t, lhs, rhs, binop_debug_loc);
1640 FDiv(bcx, lhs, rhs, binop_debug_loc)
1642 // Only zero-check integers; fp /0 is NaN
1643 bcx = base::fail_if_zero_or_overflows(bcx,
1644 expr_info(binop_expr),
1650 SDiv(bcx, lhs, rhs, binop_debug_loc)
1652 UDiv(bcx, lhs, rhs, binop_debug_loc)
1658 FRem(bcx, lhs, rhs, binop_debug_loc)
1660 // Only zero-check integers; fp %0 is NaN
1661 bcx = base::fail_if_zero_or_overflows(bcx,
1662 expr_info(binop_expr),
1663 op, lhs, rhs, lhs_t);
1665 SRem(bcx, lhs, rhs, binop_debug_loc)
1667 URem(bcx, lhs, rhs, binop_debug_loc)
1671 hir::BiBitOr => Or(bcx, lhs, rhs, binop_debug_loc),
1672 hir::BiBitAnd => And(bcx, lhs, rhs, binop_debug_loc),
1673 hir::BiBitXor => Xor(bcx, lhs, rhs, binop_debug_loc),
1675 let (newbcx, res) = with_overflow_check(
1676 bcx, OverflowOp::Shl, info, lhs_t, lhs, rhs, binop_debug_loc);
1681 let (newbcx, res) = with_overflow_check(
1682 bcx, OverflowOp::Shr, info, lhs_t, lhs, rhs, binop_debug_loc);
1686 hir::BiEq | hir::BiNe | hir::BiLt | hir::BiGe | hir::BiLe | hir::BiGt => {
1687 base::compare_scalar_types(bcx, lhs, rhs, lhs_t, op.node, binop_debug_loc)
1690 span_bug!(binop_expr.span, "unexpected binop");
1694 immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
1697 // refinement types would obviate the need for this
1698 #[derive(Clone, Copy)]
1699 enum lazy_binop_ty {
1705 fn trans_lazy_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1706 binop_expr: &hir::Expr,
1710 -> DatumBlock<'blk, 'tcx, Expr> {
1711 let _icx = push_ctxt("trans_lazy_binop");
1712 let binop_ty = expr_ty(bcx, binop_expr);
1715 let DatumBlock {bcx: past_lhs, datum: lhs} = trans(bcx, a);
1716 let lhs = lhs.to_llscalarish(past_lhs);
1718 if past_lhs.unreachable.get() {
1719 return immediate_rvalue_bcx(past_lhs, lhs, binop_ty).to_expr_datumblock();
1722 // If the rhs can never be reached, don't generate code for it.
1723 if let Some(cond_val) = const_to_opt_uint(lhs) {
1724 match (cond_val, op) {
1727 return immediate_rvalue_bcx(past_lhs, lhs, binop_ty).to_expr_datumblock();
1729 _ => { /* continue */ }
1733 let join = fcx.new_id_block("join", binop_expr.id);
1734 let before_rhs = fcx.new_id_block("before_rhs", b.id);
1737 lazy_and => CondBr(past_lhs, lhs, before_rhs.llbb, join.llbb, DebugLoc::None),
1738 lazy_or => CondBr(past_lhs, lhs, join.llbb, before_rhs.llbb, DebugLoc::None)
1741 let DatumBlock {bcx: past_rhs, datum: rhs} = trans(before_rhs, b);
1742 let rhs = rhs.to_llscalarish(past_rhs);
1744 if past_rhs.unreachable.get() {
1745 return immediate_rvalue_bcx(join, lhs, binop_ty).to_expr_datumblock();
1748 Br(past_rhs, join.llbb, DebugLoc::None);
1749 let phi = Phi(join, Type::i1(bcx.ccx()), &[lhs, rhs],
1750 &[past_lhs.llbb, past_rhs.llbb]);
1752 return immediate_rvalue_bcx(join, phi, binop_ty).to_expr_datumblock();
1755 fn trans_binary<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1760 -> DatumBlock<'blk, 'tcx, Expr> {
1761 let _icx = push_ctxt("trans_binary");
1762 let ccx = bcx.ccx();
1764 // if overloaded, would be RvalueDpsExpr
1765 assert!(!ccx.tcx().is_method_call(expr.id));
1769 trans_lazy_binop(bcx, expr, lazy_and, lhs, rhs)
1772 trans_lazy_binop(bcx, expr, lazy_or, lhs, rhs)
1776 let binop_ty = expr_ty(bcx, expr);
1778 let lhs = unpack_datum!(bcx, trans(bcx, lhs));
1779 let lhs = unpack_datum!(bcx, lhs.to_rvalue_datum(bcx, "binop_lhs"));
1780 debug!("trans_binary (expr {}): lhs={:?}", expr.id, lhs);
1781 let rhs = unpack_datum!(bcx, trans(bcx, rhs));
1782 let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "binop_rhs"));
1783 debug!("trans_binary (expr {}): rhs={:?}", expr.id, rhs);
1785 if type_is_fat_ptr(ccx.tcx(), lhs.ty) {
1786 assert!(type_is_fat_ptr(ccx.tcx(), rhs.ty),
1787 "built-in binary operators on fat pointers are homogeneous");
1788 assert_eq!(binop_ty, bcx.tcx().types.bool);
1789 let val = base::compare_scalar_types(
1796 immediate_rvalue_bcx(bcx, val, binop_ty).to_expr_datumblock()
1798 assert!(!type_is_fat_ptr(ccx.tcx(), rhs.ty),
1799 "built-in binary operators on fat pointers are homogeneous");
1800 trans_scalar_binop(bcx, expr, binop_ty, op, lhs, rhs)
1806 pub fn cast_is_noop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
1811 if let Some(&CastKind::CoercionCast) = tcx.cast_kinds.borrow().get(&expr.id) {
1815 match (t_in.builtin_deref(true, ty::NoPreference),
1816 t_out.builtin_deref(true, ty::NoPreference)) {
1817 (Some(ty::TypeAndMut{ ty: t_in, .. }), Some(ty::TypeAndMut{ ty: t_out, .. })) => {
1821 // This condition isn't redundant with the check for CoercionCast:
1822 // different types can be substituted into the same type, and
1823 // == equality can be overconservative if there are regions.
1829 fn trans_imm_cast<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1832 -> DatumBlock<'blk, 'tcx, Expr>
1834 use rustc::ty::cast::CastTy::*;
1835 use rustc::ty::cast::IntTy::*;
1837 fn int_cast(bcx: Block,
1844 let _icx = push_ctxt("int_cast");
1845 let srcsz = llsrctype.int_width();
1846 let dstsz = lldsttype.int_width();
1847 return if dstsz == srcsz {
1848 BitCast(bcx, llsrc, lldsttype)
1849 } else if srcsz > dstsz {
1850 TruncOrBitCast(bcx, llsrc, lldsttype)
1852 SExtOrBitCast(bcx, llsrc, lldsttype)
1854 ZExtOrBitCast(bcx, llsrc, lldsttype)
1858 fn float_cast(bcx: Block,
1864 let _icx = push_ctxt("float_cast");
1865 let srcsz = llsrctype.float_width();
1866 let dstsz = lldsttype.float_width();
1867 return if dstsz > srcsz {
1868 FPExt(bcx, llsrc, lldsttype)
1869 } else if srcsz > dstsz {
1870 FPTrunc(bcx, llsrc, lldsttype)
1874 let _icx = push_ctxt("trans_cast");
1876 let ccx = bcx.ccx();
1878 let t_in = expr_ty_adjusted(bcx, expr);
1879 let t_out = node_id_type(bcx, id);
1881 debug!("trans_cast({:?} as {:?})", t_in, t_out);
1882 let mut ll_t_in = type_of::immediate_type_of(ccx, t_in);
1883 let ll_t_out = type_of::immediate_type_of(ccx, t_out);
1884 // Convert the value to be cast into a ValueRef, either by-ref or
1885 // by-value as appropriate given its type:
1886 let mut datum = unpack_datum!(bcx, trans(bcx, expr));
1888 let datum_ty = monomorphize_type(bcx, datum.ty);
1890 if cast_is_noop(bcx.tcx(), expr, datum_ty, t_out) {
1892 return DatumBlock::new(bcx, datum);
1895 if type_is_fat_ptr(bcx.tcx(), t_in) {
1896 assert!(datum.kind.is_by_ref());
1897 if type_is_fat_ptr(bcx.tcx(), t_out) {
1898 return DatumBlock::new(bcx, Datum::new(
1899 PointerCast(bcx, datum.val, ll_t_out.ptr_to()),
1902 )).to_expr_datumblock();
1904 // Return the address
1905 return immediate_rvalue_bcx(bcx,
1907 Load(bcx, get_dataptr(bcx, datum.val)),
1909 t_out).to_expr_datumblock();
1913 let r_t_in = CastTy::from_ty(t_in).expect("bad input type for cast");
1914 let r_t_out = CastTy::from_ty(t_out).expect("bad output type for cast");
1916 let (llexpr, signed) = if let Int(CEnum) = r_t_in {
1917 let repr = adt::represent_type(ccx, t_in);
1918 let datum = unpack_datum!(
1919 bcx, datum.to_lvalue_datum(bcx, "trans_imm_cast", expr.id));
1920 let llexpr_ptr = datum.to_llref();
1921 let discr = adt::trans_get_discr(bcx, &repr, llexpr_ptr,
1922 Some(Type::i64(ccx)), true);
1923 ll_t_in = val_ty(discr);
1924 (discr, adt::is_discr_signed(&repr))
1926 (datum.to_llscalarish(bcx), t_in.is_signed())
1929 let newval = match (r_t_in, r_t_out) {
1930 (Ptr(_), Ptr(_)) | (FnPtr, Ptr(_)) | (RPtr(_), Ptr(_)) => {
1931 PointerCast(bcx, llexpr, ll_t_out)
1933 (Ptr(_), Int(_)) | (FnPtr, Int(_)) => PtrToInt(bcx, llexpr, ll_t_out),
1934 (Int(_), Ptr(_)) => IntToPtr(bcx, llexpr, ll_t_out),
1936 (Int(_), Int(_)) => int_cast(bcx, ll_t_out, ll_t_in, llexpr, signed),
1937 (Float, Float) => float_cast(bcx, ll_t_out, ll_t_in, llexpr),
1938 (Int(_), Float) if signed => SIToFP(bcx, llexpr, ll_t_out),
1939 (Int(_), Float) => UIToFP(bcx, llexpr, ll_t_out),
1940 (Float, Int(I)) => FPToSI(bcx, llexpr, ll_t_out),
1941 (Float, Int(_)) => FPToUI(bcx, llexpr, ll_t_out),
1943 _ => span_bug!(expr.span,
1944 "translating unsupported cast: \
1949 return immediate_rvalue_bcx(bcx, newval, t_out).to_expr_datumblock();
1952 fn trans_assign_op<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1957 -> Block<'blk, 'tcx> {
1958 let _icx = push_ctxt("trans_assign_op");
1961 debug!("trans_assign_op(expr={:?})", expr);
1963 // User-defined operator methods cannot be used with `+=` etc right now
1964 assert!(!bcx.tcx().is_method_call(expr.id));
1966 // Evaluate LHS (destination), which should be an lvalue
1967 let dst = unpack_datum!(bcx, trans_to_lvalue(bcx, dst, "assign_op"));
1968 assert!(!bcx.fcx.type_needs_drop(dst.ty));
1969 let lhs = load_ty(bcx, dst.val, dst.ty);
1970 let lhs = immediate_rvalue(lhs, dst.ty);
1972 // Evaluate RHS - FIXME(#28160) this sucks
1973 let rhs = unpack_datum!(bcx, trans(bcx, &src));
1974 let rhs = unpack_datum!(bcx, rhs.to_rvalue_datum(bcx, "assign_op_rhs"));
1976 // Perform computation and store the result
1977 let result_datum = unpack_datum!(
1978 bcx, trans_scalar_binop(bcx, expr, dst.ty, op, lhs, rhs));
1979 return result_datum.store_to(bcx, dst.val);
1982 fn auto_ref<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1983 datum: Datum<'tcx, Expr>,
1985 -> DatumBlock<'blk, 'tcx, Expr> {
1988 // Ensure cleanup of `datum` if not already scheduled and obtain
1989 // a "by ref" pointer.
1990 let lv_datum = unpack_datum!(bcx, datum.to_lvalue_datum(bcx, "autoref", expr.id));
1992 // Compute final type. Note that we are loose with the region and
1993 // mutability, since those things don't matter in trans.
1994 let referent_ty = lv_datum.ty;
1995 let ptr_ty = bcx.tcx().mk_imm_ref(bcx.tcx().mk_region(ty::ReErased), referent_ty);
1997 // Construct the resulting datum. The right datum to return here would be an Lvalue datum,
1998 // because there is cleanup scheduled and the datum doesn't own the data, but for thin pointers
1999 // we microoptimize it to be an Rvalue datum to avoid the extra alloca and level of
2000 // indirection and for thin pointers, this has no ill effects.
2001 let kind = if type_is_sized(bcx.tcx(), referent_ty) {
2002 RvalueExpr(Rvalue::new(ByValue))
2004 LvalueExpr(lv_datum.kind)
2008 let llref = lv_datum.to_llref();
2009 DatumBlock::new(bcx, Datum::new(llref, ptr_ty, kind))
2012 fn deref_multiple<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2014 datum: Datum<'tcx, Expr>,
2016 -> DatumBlock<'blk, 'tcx, Expr> {
2018 let mut datum = datum;
2020 let method_call = MethodCall::autoderef(expr.id, i as u32);
2021 datum = unpack_datum!(bcx, deref_once(bcx, expr, datum, method_call));
2023 DatumBlock { bcx: bcx, datum: datum }
2026 fn deref_once<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2028 datum: Datum<'tcx, Expr>,
2029 method_call: MethodCall)
2030 -> DatumBlock<'blk, 'tcx, Expr> {
2031 let ccx = bcx.ccx();
2033 debug!("deref_once(expr={:?}, datum={:?}, method_call={:?})",
2034 expr, datum, method_call);
2038 // Check for overloaded deref.
2039 let method = ccx.tcx().tables.borrow().method_map.get(&method_call).cloned();
2040 let datum = match method {
2042 let method_ty = monomorphize_type(bcx, method.ty);
2044 // Overloaded. Invoke the deref() method, which basically
2045 // converts from the `Smaht<T>` pointer that we have into
2046 // a `&T` pointer. We can then proceed down the normal
2047 // path (below) to dereference that `&T`.
2048 let datum = if method_call.autoderef == 0 {
2051 // Always perform an AutoPtr when applying an overloaded auto-deref
2052 unpack_datum!(bcx, auto_ref(bcx, datum, expr))
2055 let ref_ty = // invoked methods have their LB regions instantiated
2056 ccx.tcx().no_late_bound_regions(&method_ty.fn_ret()).unwrap().unwrap();
2057 let scratch = rvalue_scratch_datum(bcx, ref_ty, "overloaded_deref");
2059 bcx = Callee::method(bcx, method)
2060 .call(bcx, expr.debug_loc(),
2061 ArgOverloadedOp(datum, None),
2062 Some(SaveIn(scratch.val))).bcx;
2063 scratch.to_expr_datum()
2066 // Not overloaded. We already have a pointer we know how to deref.
2071 let r = match datum.ty.sty {
2072 ty::TyBox(content_ty) => {
2073 // Make sure we have an lvalue datum here to get the
2074 // proper cleanups scheduled
2075 let datum = unpack_datum!(
2076 bcx, datum.to_lvalue_datum(bcx, "deref", expr.id));
2078 if type_is_sized(bcx.tcx(), content_ty) {
2079 let ptr = load_ty(bcx, datum.val, datum.ty);
2080 DatumBlock::new(bcx, Datum::new(ptr, content_ty, LvalueExpr(datum.kind)))
2082 // A fat pointer and a DST lvalue have the same representation
2083 // just different types. Since there is no temporary for `*e`
2084 // here (because it is unsized), we cannot emulate the sized
2085 // object code path for running drop glue and free. Instead,
2086 // we schedule cleanup for `e`, turning it into an lvalue.
2088 let lval = Lvalue::new("expr::deref_once ty_uniq");
2089 let datum = Datum::new(datum.val, content_ty, LvalueExpr(lval));
2090 DatumBlock::new(bcx, datum)
2094 ty::TyRawPtr(ty::TypeAndMut { ty: content_ty, .. }) |
2095 ty::TyRef(_, ty::TypeAndMut { ty: content_ty, .. }) => {
2096 let lval = Lvalue::new("expr::deref_once ptr");
2097 if type_is_sized(bcx.tcx(), content_ty) {
2098 let ptr = datum.to_llscalarish(bcx);
2100 // Always generate an lvalue datum, even if datum.mode is
2101 // an rvalue. This is because datum.mode is only an
2102 // rvalue for non-owning pointers like &T or *T, in which
2103 // case cleanup *is* scheduled elsewhere, by the true
2104 // owner (or, in the case of *T, by the user).
2105 DatumBlock::new(bcx, Datum::new(ptr, content_ty, LvalueExpr(lval)))
2107 // A fat pointer and a DST lvalue have the same representation
2108 // just different types.
2109 DatumBlock::new(bcx, Datum::new(datum.val, content_ty, LvalueExpr(lval)))
2116 "deref invoked on expr of invalid type {:?}",
2121 debug!("deref_once(expr={}, method_call={:?}, result={:?})",
2122 expr.id, method_call, r.datum);
2137 fn codegen_strategy(&self) -> OverflowCodegen {
2138 use self::OverflowCodegen::{ViaIntrinsic, ViaInputCheck};
2140 OverflowOp::Add => ViaIntrinsic(OverflowOpViaIntrinsic::Add),
2141 OverflowOp::Sub => ViaIntrinsic(OverflowOpViaIntrinsic::Sub),
2142 OverflowOp::Mul => ViaIntrinsic(OverflowOpViaIntrinsic::Mul),
2144 OverflowOp::Shl => ViaInputCheck(OverflowOpViaInputCheck::Shl),
2145 OverflowOp::Shr => ViaInputCheck(OverflowOpViaInputCheck::Shr),
2150 enum OverflowCodegen {
2151 ViaIntrinsic(OverflowOpViaIntrinsic),
2152 ViaInputCheck(OverflowOpViaInputCheck),
2155 enum OverflowOpViaInputCheck { Shl, Shr, }
2158 enum OverflowOpViaIntrinsic { Add, Sub, Mul, }
2160 impl OverflowOpViaIntrinsic {
2161 fn to_intrinsic<'blk, 'tcx>(&self, bcx: Block<'blk, 'tcx>, lhs_ty: Ty) -> ValueRef {
2162 let name = self.to_intrinsic_name(bcx.tcx(), lhs_ty);
2163 bcx.ccx().get_intrinsic(&name)
2165 fn to_intrinsic_name(&self, tcx: TyCtxt, ty: Ty) -> &'static str {
2166 use syntax::ast::IntTy::*;
2167 use syntax::ast::UintTy::*;
2168 use rustc::ty::{TyInt, TyUint};
2170 let new_sty = match ty.sty {
2171 TyInt(Is) => match &tcx.sess.target.target.target_pointer_width[..] {
2175 _ => bug!("unsupported target word size")
2177 TyUint(Us) => match &tcx.sess.target.target.target_pointer_width[..] {
2178 "16" => TyUint(U16),
2179 "32" => TyUint(U32),
2180 "64" => TyUint(U64),
2181 _ => bug!("unsupported target word size")
2183 ref t @ TyUint(_) | ref t @ TyInt(_) => t.clone(),
2184 _ => bug!("tried to get overflow intrinsic for {:?} applied to non-int type",
2189 OverflowOpViaIntrinsic::Add => match new_sty {
2190 TyInt(I8) => "llvm.sadd.with.overflow.i8",
2191 TyInt(I16) => "llvm.sadd.with.overflow.i16",
2192 TyInt(I32) => "llvm.sadd.with.overflow.i32",
2193 TyInt(I64) => "llvm.sadd.with.overflow.i64",
2195 TyUint(U8) => "llvm.uadd.with.overflow.i8",
2196 TyUint(U16) => "llvm.uadd.with.overflow.i16",
2197 TyUint(U32) => "llvm.uadd.with.overflow.i32",
2198 TyUint(U64) => "llvm.uadd.with.overflow.i64",
2202 OverflowOpViaIntrinsic::Sub => match new_sty {
2203 TyInt(I8) => "llvm.ssub.with.overflow.i8",
2204 TyInt(I16) => "llvm.ssub.with.overflow.i16",
2205 TyInt(I32) => "llvm.ssub.with.overflow.i32",
2206 TyInt(I64) => "llvm.ssub.with.overflow.i64",
2208 TyUint(U8) => "llvm.usub.with.overflow.i8",
2209 TyUint(U16) => "llvm.usub.with.overflow.i16",
2210 TyUint(U32) => "llvm.usub.with.overflow.i32",
2211 TyUint(U64) => "llvm.usub.with.overflow.i64",
2215 OverflowOpViaIntrinsic::Mul => match new_sty {
2216 TyInt(I8) => "llvm.smul.with.overflow.i8",
2217 TyInt(I16) => "llvm.smul.with.overflow.i16",
2218 TyInt(I32) => "llvm.smul.with.overflow.i32",
2219 TyInt(I64) => "llvm.smul.with.overflow.i64",
2221 TyUint(U8) => "llvm.umul.with.overflow.i8",
2222 TyUint(U16) => "llvm.umul.with.overflow.i16",
2223 TyUint(U32) => "llvm.umul.with.overflow.i32",
2224 TyUint(U64) => "llvm.umul.with.overflow.i64",
2231 fn build_intrinsic_call<'blk, 'tcx>(&self, bcx: Block<'blk, 'tcx>,
2232 info: NodeIdAndSpan,
2233 lhs_t: Ty<'tcx>, lhs: ValueRef,
2235 binop_debug_loc: DebugLoc)
2236 -> (Block<'blk, 'tcx>, ValueRef) {
2237 use rustc_const_math::{ConstMathErr, Op};
2239 let llfn = self.to_intrinsic(bcx, lhs_t);
2241 let val = Call(bcx, llfn, &[lhs, rhs], binop_debug_loc);
2242 let result = ExtractValue(bcx, val, 0); // iN operation result
2243 let overflow = ExtractValue(bcx, val, 1); // i1 "did it overflow?"
2245 let cond = ICmp(bcx, llvm::IntEQ, overflow, C_integral(Type::i1(bcx.ccx()), 1, false),
2248 let expect = bcx.ccx().get_intrinsic(&"llvm.expect.i1");
2249 let expected = Call(bcx, expect, &[cond, C_bool(bcx.ccx(), false)],
2252 let op = match *self {
2253 OverflowOpViaIntrinsic::Add => Op::Add,
2254 OverflowOpViaIntrinsic::Sub => Op::Sub,
2255 OverflowOpViaIntrinsic::Mul => Op::Mul
2259 base::with_cond(bcx, expected, |bcx|
2260 controlflow::trans_fail(bcx, info,
2261 InternedString::new(ConstMathErr::Overflow(op).description())));
2267 impl OverflowOpViaInputCheck {
2268 fn build_with_input_check<'blk, 'tcx>(&self,
2269 bcx: Block<'blk, 'tcx>,
2270 info: NodeIdAndSpan,
2274 binop_debug_loc: DebugLoc)
2275 -> (Block<'blk, 'tcx>, ValueRef)
2277 use rustc_const_math::{ConstMathErr, Op};
2279 let lhs_llty = val_ty(lhs);
2280 let rhs_llty = val_ty(rhs);
2282 // Panic if any bits are set outside of bits that we always
2285 // Note that the mask's value is derived from the LHS type
2286 // (since that is where the 32/64 distinction is relevant) but
2287 // the mask's type must match the RHS type (since they will
2288 // both be fed into an and-binop)
2289 let invert_mask = shift_mask_val(bcx, lhs_llty, rhs_llty, true);
2291 let outer_bits = And(bcx, rhs, invert_mask, binop_debug_loc);
2292 let cond = build_nonzero_check(bcx, outer_bits, binop_debug_loc);
2293 let (result, op) = match *self {
2294 OverflowOpViaInputCheck::Shl =>
2295 (build_unchecked_lshift(bcx, lhs, rhs, binop_debug_loc), Op::Shl),
2296 OverflowOpViaInputCheck::Shr =>
2297 (build_unchecked_rshift(bcx, lhs_t, lhs, rhs, binop_debug_loc), Op::Shr)
2300 base::with_cond(bcx, cond, |bcx|
2301 controlflow::trans_fail(bcx, info,
2302 InternedString::new(ConstMathErr::Overflow(op).description())));
2308 // Check if an integer or vector contains a nonzero element.
2309 fn build_nonzero_check<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2311 binop_debug_loc: DebugLoc) -> ValueRef {
2312 let llty = val_ty(value);
2313 let kind = llty.kind();
2315 TypeKind::Integer => ICmp(bcx, llvm::IntNE, value, C_null(llty), binop_debug_loc),
2316 TypeKind::Vector => {
2317 // Check if any elements of the vector are nonzero by treating
2318 // it as a wide integer and checking if the integer is nonzero.
2319 let width = llty.vector_length() as u64 * llty.element_type().int_width();
2320 let int_value = BitCast(bcx, value, Type::ix(bcx.ccx(), width));
2321 build_nonzero_check(bcx, int_value, binop_debug_loc)
2323 _ => bug!("build_nonzero_check: expected Integer or Vector, found {:?}", kind),
2327 fn with_overflow_check<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, oop: OverflowOp, info: NodeIdAndSpan,
2328 lhs_t: Ty<'tcx>, lhs: ValueRef,
2330 binop_debug_loc: DebugLoc)
2331 -> (Block<'blk, 'tcx>, ValueRef) {
2332 if bcx.unreachable.get() { return (bcx, _Undef(lhs)); }
2333 if bcx.ccx().check_overflow() {
2335 match oop.codegen_strategy() {
2336 OverflowCodegen::ViaIntrinsic(oop) =>
2337 oop.build_intrinsic_call(bcx, info, lhs_t, lhs, rhs, binop_debug_loc),
2338 OverflowCodegen::ViaInputCheck(oop) =>
2339 oop.build_with_input_check(bcx, info, lhs_t, lhs, rhs, binop_debug_loc),
2342 let res = match oop {
2343 OverflowOp::Add => Add(bcx, lhs, rhs, binop_debug_loc),
2344 OverflowOp::Sub => Sub(bcx, lhs, rhs, binop_debug_loc),
2345 OverflowOp::Mul => Mul(bcx, lhs, rhs, binop_debug_loc),
2348 build_unchecked_lshift(bcx, lhs, rhs, binop_debug_loc),
2350 build_unchecked_rshift(bcx, lhs_t, lhs, rhs, binop_debug_loc),
2356 /// We categorize expressions into three kinds. The distinction between
2357 /// lvalue/rvalue is fundamental to the language. The distinction between the
2358 /// two kinds of rvalues is an artifact of trans which reflects how we will
2359 /// generate code for that kind of expression. See trans/expr.rs for more
2361 #[derive(Copy, Clone)]
2369 fn expr_kind<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, expr: &hir::Expr) -> ExprKind {
2370 if tcx.is_method_call(expr.id) {
2371 // Overloaded operations are generally calls, and hence they are
2372 // generated via DPS, but there are a few exceptions:
2373 return match expr.node {
2374 // `a += b` has a unit result.
2375 hir::ExprAssignOp(..) => ExprKind::RvalueStmt,
2377 // the deref method invoked for `*a` always yields an `&T`
2378 hir::ExprUnary(hir::UnDeref, _) => ExprKind::Lvalue,
2380 // the index method invoked for `a[i]` always yields an `&T`
2381 hir::ExprIndex(..) => ExprKind::Lvalue,
2383 // in the general case, result could be any type, use DPS
2384 _ => ExprKind::RvalueDps
2389 hir::ExprPath(..) => {
2390 match tcx.expect_def(expr.id) {
2391 // Put functions and ctors with the ADTs, as they
2392 // are zero-sized, so DPS is the cheapest option.
2393 Def::Struct(..) | Def::Variant(..) |
2394 Def::Fn(..) | Def::Method(..) => {
2398 // Note: there is actually a good case to be made that
2399 // DefArg's, particularly those of immediate type, ought to
2400 // considered rvalues.
2403 Def::Local(..) => ExprKind::Lvalue,
2406 Def::AssociatedConst(..) => ExprKind::RvalueDatum,
2411 "uncategorized def for expr {}: {:?}",
2418 hir::ExprType(ref expr, _) => {
2419 expr_kind(tcx, expr)
2422 hir::ExprUnary(hir::UnDeref, _) |
2423 hir::ExprField(..) |
2424 hir::ExprTupField(..) |
2425 hir::ExprIndex(..) => {
2430 hir::ExprMethodCall(..) |
2431 hir::ExprStruct(..) |
2434 hir::ExprMatch(..) |
2435 hir::ExprClosure(..) |
2436 hir::ExprBlock(..) |
2437 hir::ExprRepeat(..) |
2438 hir::ExprVec(..) => {
2442 hir::ExprLit(ref lit) if lit.node.is_str() => {
2446 hir::ExprBreak(..) |
2447 hir::ExprAgain(..) |
2449 hir::ExprWhile(..) |
2451 hir::ExprAssign(..) |
2452 hir::ExprInlineAsm(..) |
2453 hir::ExprAssignOp(..) => {
2454 ExprKind::RvalueStmt
2457 hir::ExprLit(_) | // Note: LitStr is carved out above
2458 hir::ExprUnary(..) |
2460 hir::ExprAddrOf(..) |
2461 hir::ExprBinary(..) |
2462 hir::ExprCast(..) => {
2463 ExprKind::RvalueDatum