1 use rustc::middle::lang_items;
2 use rustc::ty::{self, Ty, TypeFoldable, Instance};
3 use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, FnTypeExt};
4 use rustc::mir::{self, Place, PlaceBase, Static, StaticKind};
5 use rustc::mir::interpret::InterpError;
6 use rustc_target::abi::call::{ArgType, FnType, PassMode, IgnoreMode};
7 use rustc_target::spec::abi::Abi;
10 use crate::common::{self, IntPredicate};
17 use syntax::symbol::LocalInternedString;
20 use super::{FunctionCx, LocalRef};
21 use super::place::PlaceRef;
22 use super::operand::OperandRef;
23 use super::operand::OperandValue::{Pair, Ref, Immediate};
25 /// Used by `FunctionCx::codegen_terminator` for emitting common patterns
26 /// e.g., creating a basic block, calling a function, etc.
27 struct TerminatorCodegenHelper<'a, 'tcx> {
28 bb: &'a mir::BasicBlock,
29 terminator: &'a mir::Terminator<'tcx>,
30 funclet_bb: Option<mir::BasicBlock>,
33 impl<'a, 'tcx> TerminatorCodegenHelper<'a, 'tcx> {
34 /// Returns the associated funclet from `FunctionCx::funclets` for the
35 /// `funclet_bb` member if it is not `None`.
36 fn funclet<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
38 fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
39 ) -> Option<&'c Bx::Funclet> {
40 match self.funclet_bb {
41 Some(funcl) => fx.funclets[funcl].as_ref(),
46 fn lltarget<'b, 'c, Bx: BuilderMethods<'b, 'tcx>>(
48 fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
49 target: mir::BasicBlock,
50 ) -> (Bx::BasicBlock, bool) {
51 let span = self.terminator.source_info.span;
52 let lltarget = fx.blocks[target];
53 let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
54 match (self.funclet_bb, target_funclet) {
55 (None, None) => (lltarget, false),
56 (Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) =>
58 // jump *into* cleanup - need a landing pad if GNU
59 (None, Some(_)) => (fx.landing_pad_to(target), false),
60 (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
61 (Some(_), Some(_)) => (fx.landing_pad_to(target), true),
65 /// Create a basic block.
66 fn llblock<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
68 fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
69 target: mir::BasicBlock,
71 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
73 // MSVC cross-funclet jump - need a trampoline
75 debug!("llblock: creating cleanup trampoline for {:?}", target);
76 let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
77 let mut trampoline = fx.new_block(name);
78 trampoline.cleanup_ret(self.funclet(fx).unwrap(),
86 fn funclet_br<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
88 fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
90 target: mir::BasicBlock,
92 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
94 // micro-optimization: generate a `ret` rather than a jump
96 bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
102 /// Call `fn_ptr` of `fn_ty` with the arguments `llargs`, the optional
103 /// return destination `destination` and the cleanup function `cleanup`.
104 fn do_call<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
106 fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
108 fn_ty: FnType<'tcx, Ty<'tcx>>,
110 llargs: &[Bx::Value],
111 destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>,
112 cleanup: Option<mir::BasicBlock>,
114 if let Some(cleanup) = cleanup {
115 let ret_bx = if let Some((_, target)) = destination {
118 fx.unreachable_block()
120 let invokeret = bx.invoke(fn_ptr,
123 self.llblock(fx, cleanup),
125 bx.apply_attrs_callsite(&fn_ty, invokeret);
127 if let Some((ret_dest, target)) = destination {
128 let mut ret_bx = fx.build_block(target);
129 fx.set_debug_loc(&mut ret_bx, self.terminator.source_info);
130 fx.store_return(&mut ret_bx, ret_dest, &fn_ty.ret, invokeret);
133 let llret = bx.call(fn_ptr, &llargs, self.funclet(fx));
134 bx.apply_attrs_callsite(&fn_ty, llret);
135 if fx.mir[*self.bb].is_cleanup {
136 // Cleanup is always the cold path. Don't inline
137 // drop glue. Also, when there is a deeply-nested
138 // struct, there are "symmetry" issues that cause
139 // exponential inlining - see issue #41696.
140 bx.do_not_inline(llret);
143 if let Some((ret_dest, target)) = destination {
144 fx.store_return(bx, ret_dest, &fn_ty.ret, llret);
145 self.funclet_br(fx, bx, target);
153 /// Codegen implementations for some terminator variants.
154 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
155 /// Generates code for a `Resume` terminator.
156 fn codegen_resume_terminator<'b>(
158 helper: TerminatorCodegenHelper<'b, 'tcx>,
161 if let Some(funclet) = helper.funclet(self) {
162 bx.cleanup_ret(funclet, None);
164 let slot = self.get_personality_slot(&mut bx);
165 let lp0 = slot.project_field(&mut bx, 0);
166 let lp0 = bx.load_operand(lp0).immediate();
167 let lp1 = slot.project_field(&mut bx, 1);
168 let lp1 = bx.load_operand(lp1).immediate();
169 slot.storage_dead(&mut bx);
171 if !bx.sess().target.target.options.custom_unwind_resume {
172 let mut lp = bx.const_undef(self.landing_pad_type());
173 lp = bx.insert_value(lp, lp0, 0);
174 lp = bx.insert_value(lp, lp1, 1);
177 bx.call(bx.eh_unwind_resume(), &[lp0],
178 helper.funclet(self));
184 fn codegen_switchint_terminator<'b>(
186 helper: TerminatorCodegenHelper<'b, 'tcx>,
188 discr: &mir::Operand<'tcx>,
190 values: &Cow<'tcx, [u128]>,
191 targets: &Vec<mir::BasicBlock>,
193 let discr = self.codegen_operand(&mut bx, &discr);
194 if targets.len() == 2 {
195 // If there are two targets, emit br instead of switch
196 let lltrue = helper.llblock(self, targets[0]);
197 let llfalse = helper.llblock(self, targets[1]);
198 if switch_ty == bx.tcx().types.bool {
199 // Don't generate trivial icmps when switching on bool
200 if let [0] = values[..] {
201 bx.cond_br(discr.immediate(), llfalse, lltrue);
203 assert_eq!(&values[..], &[1]);
204 bx.cond_br(discr.immediate(), lltrue, llfalse);
207 let switch_llty = bx.immediate_backend_type(
208 bx.layout_of(switch_ty)
210 let llval = bx.const_uint_big(switch_llty, values[0]);
211 let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval);
212 bx.cond_br(cmp, lltrue, llfalse);
215 let (otherwise, targets) = targets.split_last().unwrap();
218 helper.llblock(self, *otherwise),
219 values.iter().zip(targets).map(|(&value, target)| {
220 (value, helper.llblock(self, *target))
226 fn codegen_return_terminator<'b>(
230 if self.fn_ty.c_variadic {
231 match self.va_list_ref {
233 bx.va_end(va_list.llval);
236 bug!("C-variadic function must have a `va_list_ref`");
240 if self.fn_ty.ret.layout.abi.is_uninhabited() {
241 // Functions with uninhabited return values are marked `noreturn`,
242 // so we should make sure that we never actually do.
247 let llval = match self.fn_ty.ret.mode {
248 PassMode::Ignore(IgnoreMode::Zst) | PassMode::Indirect(..) => {
253 PassMode::Ignore(IgnoreMode::CVarArgs) => {
254 bug!("C-variadic arguments should never be the return type");
257 PassMode::Direct(_) | PassMode::Pair(..) => {
259 self.codegen_consume(&mut bx, &mir::Place::RETURN_PLACE);
260 if let Ref(llval, _, align) = op.val {
261 bx.load(llval, align)
263 op.immediate_or_packed_pair(&mut bx)
267 PassMode::Cast(cast_ty) => {
268 let op = match self.locals[mir::RETURN_PLACE] {
269 LocalRef::Operand(Some(op)) => op,
270 LocalRef::Operand(None) => bug!("use of return before def"),
271 LocalRef::Place(cg_place) => {
273 val: Ref(cg_place.llval, None, cg_place.align),
274 layout: cg_place.layout
277 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
279 let llslot = match op.val {
280 Immediate(_) | Pair(..) => {
282 PlaceRef::alloca(&mut bx, self.fn_ty.ret.layout, "ret");
283 op.val.store(&mut bx, scratch);
286 Ref(llval, _, align) => {
287 assert_eq!(align, op.layout.align.abi,
288 "return place is unaligned!");
292 let addr = bx.pointercast(llslot, bx.type_ptr_to(
293 bx.cast_backend_type(&cast_ty)
295 bx.load(addr, self.fn_ty.ret.layout.align.abi)
302 fn codegen_drop_terminator<'b>(
304 helper: TerminatorCodegenHelper<'b, 'tcx>,
306 location: &mir::Place<'tcx>,
307 target: mir::BasicBlock,
308 unwind: Option<mir::BasicBlock>,
310 let ty = location.ty(self.mir, bx.tcx()).ty;
311 let ty = self.monomorphize(&ty);
312 let drop_fn = Instance::resolve_drop_in_place(bx.tcx(), ty);
314 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
315 // we don't actually need to drop anything.
316 helper.funclet_br(self, &mut bx, target);
320 let place = self.codegen_place(&mut bx, location);
322 let mut args = if let Some(llextra) = place.llextra {
323 args2 = [place.llval, llextra];
326 args1 = [place.llval];
329 let (drop_fn, fn_ty) = match ty.sty {
331 let sig = drop_fn.fn_sig(self.cx.tcx());
332 let sig = self.cx.tcx().normalize_erasing_late_bound_regions(
333 ty::ParamEnv::reveal_all(),
336 let fn_ty = FnType::new_vtable(&bx, sig, &[]);
337 let vtable = args[1];
339 (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_ty), fn_ty)
343 FnType::of_instance(&bx, &drop_fn))
346 helper.do_call(self, &mut bx, fn_ty, drop_fn, args,
347 Some((ReturnDest::Nothing, target)),
351 fn codegen_assert_terminator<'b>(
353 helper: TerminatorCodegenHelper<'b, 'tcx>,
355 terminator: &mir::Terminator<'tcx>,
356 cond: &mir::Operand<'tcx>,
358 msg: &mir::AssertMessage<'tcx>,
359 target: mir::BasicBlock,
360 cleanup: Option<mir::BasicBlock>,
362 let span = terminator.source_info.span;
363 let cond = self.codegen_operand(&mut bx, cond).immediate();
364 let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
366 // This case can currently arise only from functions marked
367 // with #[rustc_inherit_overflow_checks] and inlined from
368 // another crate (mostly core::num generic/#[inline] fns),
369 // while the current crate doesn't use overflow checks.
370 // NOTE: Unlike binops, negation doesn't have its own
371 // checked operation, just a comparison with the minimum
372 // value, so we have to check for the assert message.
373 if !bx.check_overflow() {
374 if let mir::interpret::InterpError::OverflowNeg = *msg {
375 const_cond = Some(expected);
379 // Don't codegen the panic block if success if known.
380 if const_cond == Some(expected) {
381 helper.funclet_br(self, &mut bx, target);
385 // Pass the condition through llvm.expect for branch hinting.
386 let cond = bx.expect(cond, expected);
388 // Create the failure block and the conditional branch to it.
389 let lltarget = helper.llblock(self, target);
390 let panic_block = self.new_block("panic");
392 bx.cond_br(cond, lltarget, panic_block.llbb());
394 bx.cond_br(cond, panic_block.llbb(), lltarget);
397 // After this point, bx is the block for the call to panic.
399 self.set_debug_loc(&mut bx, terminator.source_info);
401 // Get the location information.
402 let loc = bx.sess().source_map().lookup_char_pos(span.lo());
403 let filename = LocalInternedString::intern(&loc.file.name.to_string());
404 let line = bx.const_u32(loc.line as u32);
405 let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
407 // Put together the arguments to the panic entry point.
408 let (lang_item, args) = match *msg {
409 InterpError::BoundsCheck { ref len, ref index } => {
410 let len = self.codegen_operand(&mut bx, len).immediate();
411 let index = self.codegen_operand(&mut bx, index).immediate();
413 let file_line_col = bx.static_panic_msg(
418 "panic_bounds_check_loc",
420 (lang_items::PanicBoundsCheckFnLangItem,
421 vec![file_line_col, index, len])
424 let str = msg.description();
425 let msg_str = LocalInternedString::intern(str);
426 let msg_file_line_col = bx.static_panic_msg(
433 (lang_items::PanicFnLangItem,
434 vec![msg_file_line_col])
438 // Obtain the panic entry point.
439 let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
440 let instance = ty::Instance::mono(bx.tcx(), def_id);
441 let fn_ty = FnType::of_instance(&bx, &instance);
442 let llfn = bx.get_fn(instance);
444 // Codegen the actual panic invoke/call.
445 helper.do_call(self, &mut bx, fn_ty, llfn, &args, None, cleanup);
448 fn codegen_call_terminator<'b>(
450 helper: TerminatorCodegenHelper<'b, 'tcx>,
452 terminator: &mir::Terminator<'tcx>,
453 func: &mir::Operand<'tcx>,
454 args: &Vec<mir::Operand<'tcx>>,
455 destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
456 cleanup: Option<mir::BasicBlock>,
458 let span = terminator.source_info.span;
459 // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
460 let callee = self.codegen_operand(&mut bx, func);
462 let (instance, mut llfn) = match callee.layout.ty.sty {
463 ty::FnDef(def_id, substs) => {
464 (Some(ty::Instance::resolve(bx.tcx(),
465 ty::ParamEnv::reveal_all(),
471 (None, Some(callee.immediate()))
473 _ => bug!("{} is not callable", callee.layout.ty),
475 let def = instance.map(|i| i.def);
476 let sig = callee.layout.ty.fn_sig(bx.tcx());
477 let sig = bx.tcx().normalize_erasing_late_bound_regions(
478 ty::ParamEnv::reveal_all(),
483 // Handle intrinsics old codegen wants Expr's for, ourselves.
484 let intrinsic = match def {
485 Some(ty::InstanceDef::Intrinsic(def_id)) =>
486 Some(bx.tcx().item_name(def_id).as_str()),
489 let intrinsic = intrinsic.as_ref().map(|s| &s[..]);
491 if intrinsic == Some("transmute") {
492 if let Some(destination_ref) = destination.as_ref() {
493 let &(ref dest, target) = destination_ref;
494 self.codegen_transmute(&mut bx, &args[0], dest);
495 helper.funclet_br(self, &mut bx, target);
497 // If we are trying to transmute to an uninhabited type,
498 // it is likely there is no allotted destination. In fact,
499 // transmuting to an uninhabited type is UB, which means
500 // we can do what we like. Here, we declare that transmuting
501 // into an uninhabited type is impossible, so anything following
502 // it must be unreachable.
503 assert_eq!(bx.layout_of(sig.output()).abi, layout::Abi::Uninhabited);
509 // The "spoofed" `VaList` added to a C-variadic functions signature
510 // should not be included in the `extra_args` calculation.
511 let extra_args_start_idx = sig.inputs().len() - if sig.c_variadic { 1 } else { 0 };
512 let extra_args = &args[extra_args_start_idx..];
513 let extra_args = extra_args.iter().map(|op_arg| {
514 let op_ty = op_arg.ty(self.mir, bx.tcx());
515 self.monomorphize(&op_ty)
516 }).collect::<Vec<_>>();
518 let fn_ty = match def {
519 Some(ty::InstanceDef::Virtual(..)) => {
520 FnType::new_vtable(&bx, sig, &extra_args)
522 Some(ty::InstanceDef::DropGlue(_, None)) => {
523 // Empty drop glue; a no-op.
524 let &(_, target) = destination.as_ref().unwrap();
525 helper.funclet_br(self, &mut bx, target);
528 _ => FnType::new(&bx, sig, &extra_args)
531 // Emit a panic or a no-op for `panic_if_uninhabited`.
532 if intrinsic == Some("panic_if_uninhabited") {
533 let ty = instance.unwrap().substs.type_at(0);
534 let layout = bx.layout_of(ty);
535 if layout.abi.is_uninhabited() {
536 let loc = bx.sess().source_map().lookup_char_pos(span.lo());
537 let filename = LocalInternedString::intern(&loc.file.name.to_string());
538 let line = bx.const_u32(loc.line as u32);
539 let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
542 "Attempted to instantiate uninhabited type {}",
545 let msg_str = LocalInternedString::intern(&str);
546 let msg_file_line_col = bx.static_panic_msg(
554 // Obtain the panic entry point.
556 common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
557 let instance = ty::Instance::mono(bx.tcx(), def_id);
558 let fn_ty = FnType::of_instance(&bx, &instance);
559 let llfn = bx.get_fn(instance);
561 // Codegen the actual panic invoke/call.
567 &[msg_file_line_col],
568 destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
573 helper.funclet_br(self, &mut bx, destination.as_ref().unwrap().1)
578 // The arguments we'll be passing. Plus one to account for outptr, if used.
579 let arg_count = fn_ty.args.len() + fn_ty.ret.is_indirect() as usize;
580 let mut llargs = Vec::with_capacity(arg_count);
582 // Prepare the return value destination
583 let ret_dest = if let Some((ref dest, _)) = *destination {
584 let is_intrinsic = intrinsic.is_some();
585 self.make_return_dest(&mut bx, dest, &fn_ty.ret, &mut llargs,
591 if intrinsic.is_some() && intrinsic != Some("drop_in_place") {
592 let dest = match ret_dest {
593 _ if fn_ty.ret.is_indirect() => llargs[0],
594 ReturnDest::Nothing =>
595 bx.const_undef(bx.type_ptr_to(bx.memory_ty(&fn_ty.ret))),
596 ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) =>
598 ReturnDest::DirectOperand(_) =>
599 bug!("Cannot use direct operand with an intrinsic call"),
602 let args: Vec<_> = args.iter().enumerate().map(|(i, arg)| {
603 // The indices passed to simd_shuffle* in the
604 // third argument must be constant. This is
605 // checked by const-qualification, which also
606 // promotes any complex rvalues to constants.
607 if i == 2 && intrinsic.unwrap().starts_with("simd_shuffle") {
609 // The shuffle array argument is usually not an explicit constant,
610 // but specified directly in the code. This means it gets promoted
611 // and we can then extract the value by evaluating the promoted.
615 box Static { kind: StaticKind::Promoted(promoted), ty }
622 box Static { kind: StaticKind::Promoted(promoted), ty }
626 let param_env = ty::ParamEnv::reveal_all();
627 let cid = mir::interpret::GlobalId {
628 instance: self.instance,
629 promoted: Some(promoted),
631 let c = bx.tcx().const_eval(param_env.and(cid));
632 let (llval, ty) = self.simd_shuffle_indices(
634 terminator.source_info.span,
639 val: Immediate(llval),
640 layout: bx.layout_of(ty),
644 mir::Operand::Copy(_) |
645 mir::Operand::Move(_) => {
646 span_bug!(span, "shuffle indices must be constant");
648 mir::Operand::Constant(ref constant) => {
649 let c = self.eval_mir_constant(constant);
650 let (llval, ty) = self.simd_shuffle_indices(
657 val: Immediate(llval),
658 layout: bx.layout_of(ty)
664 self.codegen_operand(&mut bx, arg)
668 let callee_ty = instance.as_ref().unwrap().ty(bx.tcx());
669 bx.codegen_intrinsic_call(callee_ty, &fn_ty, &args, dest,
670 terminator.source_info.span);
672 if let ReturnDest::IndirectOperand(dst, _) = ret_dest {
673 self.store_return(&mut bx, ret_dest, &fn_ty.ret, dst.llval);
676 if let Some((_, target)) = *destination {
677 helper.funclet_br(self, &mut bx, target);
685 // Split the rust-call tupled arguments off.
686 let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() {
687 let (tup, args) = args.split_last().unwrap();
693 // Useful determining if the current argument is the "spoofed" `VaList`
694 let last_arg_idx = if sig.inputs().is_empty() {
697 Some(sig.inputs().len() - 1)
699 'make_args: for (i, arg) in first_args.iter().enumerate() {
700 // If this is a C-variadic function the function signature contains
701 // an "spoofed" `VaList`. This argument is ignored, but we need to
702 // populate it with a dummy operand so that the users real arguments
703 // are not overwritten.
704 let i = if sig.c_variadic && last_arg_idx.map(|x| i >= x).unwrap_or(false) {
705 if i + 1 < fn_ty.args.len() {
713 let mut op = self.codegen_operand(&mut bx, arg);
715 if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) {
716 if let Pair(..) = op.val {
717 // In the case of Rc<Self>, we need to explicitly pass a
718 // *mut RcBox<Self> with a Scalar (not ScalarPair) ABI. This is a hack
719 // that is understood elsewhere in the compiler as a method on
721 // To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
722 // we get a value of a built-in pointer type
723 'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
724 && !op.layout.ty.is_region_ptr()
726 'iter_fields: for i in 0..op.layout.fields.count() {
727 let field = op.extract_field(&mut bx, i);
728 if !field.layout.is_zst() {
729 // we found the one non-zero-sized field that is allowed
730 // now find *its* non-zero-sized field, or stop if it's a
733 continue 'descend_newtypes
737 span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
740 // now that we have `*dyn Trait` or `&dyn Trait`, split it up into its
741 // data pointer and vtable. Look up the method in the vtable, and pass
742 // the data pointer as the first argument
744 Pair(data_ptr, meta) => {
745 llfn = Some(meth::VirtualIndex::from_index(idx)
746 .get_fn(&mut bx, meta, &fn_ty));
747 llargs.push(data_ptr);
750 other => bug!("expected a Pair, got {:?}", other),
752 } else if let Ref(data_ptr, Some(meta), _) = op.val {
753 // by-value dynamic dispatch
754 llfn = Some(meth::VirtualIndex::from_index(idx)
755 .get_fn(&mut bx, meta, &fn_ty));
756 llargs.push(data_ptr);
759 span_bug!(span, "can't codegen a virtual call on {:?}", op);
763 // The callee needs to own the argument memory if we pass it
764 // by-ref, so make a local copy of non-immediate constants.
765 match (arg, op.val) {
766 (&mir::Operand::Copy(_), Ref(_, None, _)) |
767 (&mir::Operand::Constant(_), Ref(_, None, _)) => {
768 let tmp = PlaceRef::alloca(&mut bx, op.layout, "const");
769 op.val.store(&mut bx, tmp);
770 op.val = Ref(tmp.llval, None, tmp.align);
775 self.codegen_argument(&mut bx, op, &mut llargs, &fn_ty.args[i]);
777 if let Some(tup) = untuple {
778 self.codegen_arguments_untupled(&mut bx, tup, &mut llargs,
779 &fn_ty.args[first_args.len()..])
782 let fn_ptr = match (llfn, instance) {
783 (Some(llfn), _) => llfn,
784 (None, Some(instance)) => bx.get_fn(instance),
785 _ => span_bug!(span, "no llfn for call"),
788 helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs,
789 destination.as_ref().map(|&(_, target)| (ret_dest, target)),
794 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
795 pub fn codegen_block(
799 let mut bx = self.build_block(bb);
800 let data = &self.mir[bb];
802 debug!("codegen_block({:?}={:?})", bb, data);
804 for statement in &data.statements {
805 bx = self.codegen_statement(bx, statement);
808 self.codegen_terminator(bx, bb, data.terminator());
811 fn codegen_terminator(
815 terminator: &mir::Terminator<'tcx>
817 debug!("codegen_terminator: {:?}", terminator);
819 // Create the cleanup bundle, if needed.
820 let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
821 let helper = TerminatorCodegenHelper {
822 bb: &bb, terminator, funclet_bb
825 self.set_debug_loc(&mut bx, terminator.source_info);
826 match terminator.kind {
827 mir::TerminatorKind::Resume => {
828 self.codegen_resume_terminator(helper, bx)
831 mir::TerminatorKind::Abort => {
836 mir::TerminatorKind::Goto { target } => {
837 helper.funclet_br(self, &mut bx, target);
840 mir::TerminatorKind::SwitchInt {
841 ref discr, switch_ty, ref values, ref targets
843 self.codegen_switchint_terminator(helper, bx, discr, switch_ty,
847 mir::TerminatorKind::Return => {
848 self.codegen_return_terminator(bx);
851 mir::TerminatorKind::Unreachable => {
855 mir::TerminatorKind::Drop { ref location, target, unwind } => {
856 self.codegen_drop_terminator(helper, bx, location, target, unwind);
859 mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
860 self.codegen_assert_terminator(helper, bx, terminator, cond,
861 expected, msg, target, cleanup);
864 mir::TerminatorKind::DropAndReplace { .. } => {
865 bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
868 mir::TerminatorKind::Call {
875 self.codegen_call_terminator(helper, bx, terminator, func,
876 args, destination, cleanup);
878 mir::TerminatorKind::GeneratorDrop |
879 mir::TerminatorKind::Yield { .. } => bug!("generator ops in codegen"),
880 mir::TerminatorKind::FalseEdges { .. } |
881 mir::TerminatorKind::FalseUnwind { .. } => bug!("borrowck false edges in codegen"),
888 op: OperandRef<'tcx, Bx::Value>,
889 llargs: &mut Vec<Bx::Value>,
890 arg: &ArgType<'tcx, Ty<'tcx>>
892 // Fill padding with undef value, where applicable.
893 if let Some(ty) = arg.pad {
894 llargs.push(bx.const_undef(bx.reg_backend_type(&ty)))
901 if let PassMode::Pair(..) = arg.mode {
908 _ => bug!("codegen_argument: {:?} invalid for pair argument", op)
910 } else if arg.is_unsized_indirect() {
912 Ref(a, Some(b), _) => {
917 _ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op)
921 // Force by-ref if we have to load through a cast pointer.
922 let (mut llval, align, by_ref) = match op.val {
923 Immediate(_) | Pair(..) => {
925 PassMode::Indirect(..) | PassMode::Cast(_) => {
926 let scratch = PlaceRef::alloca(bx, arg.layout, "arg");
927 op.val.store(bx, scratch);
928 (scratch.llval, scratch.align, true)
931 (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false)
935 Ref(llval, _, align) => {
936 if arg.is_indirect() && align < arg.layout.align.abi {
937 // `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I
938 // think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't
939 // have scary latent bugs around.
941 let scratch = PlaceRef::alloca(bx, arg.layout, "arg");
942 base::memcpy_ty(bx, scratch.llval, scratch.align, llval, align,
943 op.layout, MemFlags::empty());
944 (scratch.llval, scratch.align, true)
951 if by_ref && !arg.is_indirect() {
952 // Have to load the argument, maybe while casting it.
953 if let PassMode::Cast(ty) = arg.mode {
954 let addr = bx.pointercast(llval, bx.type_ptr_to(
955 bx.cast_backend_type(&ty))
957 llval = bx.load(addr, align.min(arg.layout.align.abi));
959 // We can't use `PlaceRef::load` here because the argument
960 // may have a type we don't treat as immediate, but the ABI
961 // used for this call is passing it by-value. In that case,
962 // the load would just produce `OperandValue::Ref` instead
963 // of the `OperandValue::Immediate` we need for the call.
964 llval = bx.load(llval, align);
965 if let layout::Abi::Scalar(ref scalar) = arg.layout.abi {
966 if scalar.is_bool() {
967 bx.range_metadata(llval, 0..2);
970 // We store bools as `i8` so we need to truncate to `i1`.
971 llval = base::to_immediate(bx, llval, arg.layout);
978 fn codegen_arguments_untupled(
981 operand: &mir::Operand<'tcx>,
982 llargs: &mut Vec<Bx::Value>,
983 args: &[ArgType<'tcx, Ty<'tcx>>]
985 let tuple = self.codegen_operand(bx, operand);
987 // Handle both by-ref and immediate tuples.
988 if let Ref(llval, None, align) = tuple.val {
989 let tuple_ptr = PlaceRef::new_sized(llval, tuple.layout, align);
990 for i in 0..tuple.layout.fields.count() {
991 let field_ptr = tuple_ptr.project_field(bx, i);
992 let field = bx.load_operand(field_ptr);
993 self.codegen_argument(bx, field, llargs, &args[i]);
995 } else if let Ref(_, Some(_), _) = tuple.val {
996 bug!("closure arguments must be sized")
998 // If the tuple is immediate, the elements are as well.
999 for i in 0..tuple.layout.fields.count() {
1000 let op = tuple.extract_field(bx, i);
1001 self.codegen_argument(bx, op, llargs, &args[i]);
1006 fn get_personality_slot(
1009 ) -> PlaceRef<'tcx, Bx::Value> {
1011 if let Some(slot) = self.personality_slot {
1014 let layout = cx.layout_of(cx.tcx().intern_tup(&[
1015 cx.tcx().mk_mut_ptr(cx.tcx().types.u8),
1018 let slot = PlaceRef::alloca(bx, layout, "personalityslot");
1019 self.personality_slot = Some(slot);
1024 /// Returns the landing-pad wrapper around the given basic block.
1026 /// No-op in MSVC SEH scheme.
1029 target_bb: mir::BasicBlock
1030 ) -> Bx::BasicBlock {
1031 if let Some(block) = self.landing_pads[target_bb] {
1035 let block = self.blocks[target_bb];
1036 let landing_pad = self.landing_pad_uncached(block);
1037 self.landing_pads[target_bb] = Some(landing_pad);
1041 fn landing_pad_uncached(
1043 target_bb: Bx::BasicBlock
1044 ) -> Bx::BasicBlock {
1045 if base::wants_msvc_seh(self.cx.sess()) {
1046 span_bug!(self.mir.span, "landing pad was not inserted?")
1049 let mut bx = self.new_block("cleanup");
1051 let llpersonality = self.cx.eh_personality();
1052 let llretty = self.landing_pad_type();
1053 let lp = bx.landing_pad(llretty, llpersonality, 1);
1056 let slot = self.get_personality_slot(&mut bx);
1057 slot.storage_live(&mut bx);
1058 Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot);
1064 fn landing_pad_type(&self) -> Bx::Type {
1066 cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
1069 fn unreachable_block(
1071 ) -> Bx::BasicBlock {
1072 self.unreachable_block.unwrap_or_else(|| {
1073 let mut bx = self.new_block("unreachable");
1075 self.unreachable_block = Some(bx.llbb());
1080 pub fn new_block(&self, name: &str) -> Bx {
1081 Bx::new_block(self.cx, self.llfn, name)
1088 let mut bx = Bx::with_cx(self.cx);
1089 bx.position_at_end(self.blocks[bb]);
1093 fn make_return_dest(
1096 dest: &mir::Place<'tcx>,
1097 fn_ret: &ArgType<'tcx, Ty<'tcx>>,
1098 llargs: &mut Vec<Bx::Value>, is_intrinsic: bool
1099 ) -> ReturnDest<'tcx, Bx::Value> {
1100 // If the return is ignored, we can just return a do-nothing `ReturnDest`.
1101 if fn_ret.is_ignore() {
1102 return ReturnDest::Nothing;
1104 let dest = if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dest {
1105 match self.locals[index] {
1106 LocalRef::Place(dest) => dest,
1107 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
1108 LocalRef::Operand(None) => {
1109 // Handle temporary places, specifically `Operand` ones, as
1110 // they don't have `alloca`s.
1111 return if fn_ret.is_indirect() {
1112 // Odd, but possible, case, we have an operand temporary,
1113 // but the calling convention has an indirect return.
1114 let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret");
1115 tmp.storage_live(bx);
1116 llargs.push(tmp.llval);
1117 ReturnDest::IndirectOperand(tmp, index)
1118 } else if is_intrinsic {
1119 // Currently, intrinsics always need a location to store
1120 // the result, so we create a temporary `alloca` for the
1122 let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret");
1123 tmp.storage_live(bx);
1124 ReturnDest::IndirectOperand(tmp, index)
1126 ReturnDest::DirectOperand(index)
1129 LocalRef::Operand(Some(_)) => {
1130 bug!("place local already assigned to");
1134 self.codegen_place(bx, dest)
1136 if fn_ret.is_indirect() {
1137 if dest.align < dest.layout.align.abi {
1138 // Currently, MIR code generation does not create calls
1139 // that store directly to fields of packed structs (in
1140 // fact, the calls it creates write only to temps).
1142 // If someone changes that, please update this code path
1143 // to create a temporary.
1144 span_bug!(self.mir.span, "can't directly store to unaligned value");
1146 llargs.push(dest.llval);
1149 ReturnDest::Store(dest)
1153 fn codegen_transmute(
1156 src: &mir::Operand<'tcx>,
1157 dst: &mir::Place<'tcx>
1159 if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dst {
1160 match self.locals[index] {
1161 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
1162 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
1163 LocalRef::Operand(None) => {
1164 let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst));
1165 assert!(!dst_layout.ty.has_erasable_regions());
1166 let place = PlaceRef::alloca(bx, dst_layout, "transmute_temp");
1167 place.storage_live(bx);
1168 self.codegen_transmute_into(bx, src, place);
1169 let op = bx.load_operand(place);
1170 place.storage_dead(bx);
1171 self.locals[index] = LocalRef::Operand(Some(op));
1173 LocalRef::Operand(Some(op)) => {
1174 assert!(op.layout.is_zst(),
1175 "assigning to initialized SSAtemp");
1179 let dst = self.codegen_place(bx, dst);
1180 self.codegen_transmute_into(bx, src, dst);
1184 fn codegen_transmute_into(
1187 src: &mir::Operand<'tcx>,
1188 dst: PlaceRef<'tcx, Bx::Value>
1190 let src = self.codegen_operand(bx, src);
1191 let llty = bx.backend_type(src.layout);
1192 let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty));
1193 let align = src.layout.align.abi.min(dst.align);
1194 src.val.store(bx, PlaceRef::new_sized(cast_ptr, src.layout, align));
1198 // Stores the return value of a function call into it's final location.
1202 dest: ReturnDest<'tcx, Bx::Value>,
1203 ret_ty: &ArgType<'tcx, Ty<'tcx>>,
1206 use self::ReturnDest::*;
1210 Store(dst) => bx.store_arg_ty(&ret_ty, llval, dst),
1211 IndirectOperand(tmp, index) => {
1212 let op = bx.load_operand(tmp);
1213 tmp.storage_dead(bx);
1214 self.locals[index] = LocalRef::Operand(Some(op));
1216 DirectOperand(index) => {
1217 // If there is a cast, we have to store and reload.
1218 let op = if let PassMode::Cast(_) = ret_ty.mode {
1219 let tmp = PlaceRef::alloca(bx, ret_ty.layout, "tmp_ret");
1220 tmp.storage_live(bx);
1221 bx.store_arg_ty(&ret_ty, llval, tmp);
1222 let op = bx.load_operand(tmp);
1223 tmp.storage_dead(bx);
1226 OperandRef::from_immediate_or_packed_pair(bx, llval, ret_ty.layout)
1228 self.locals[index] = LocalRef::Operand(Some(op));
1234 enum ReturnDest<'tcx, V> {
1235 // Do nothing; the return value is indirect or ignored.
1237 // Store the return value to the pointer.
1238 Store(PlaceRef<'tcx, V>),
1239 // Store an indirect return value to an operand local place.
1240 IndirectOperand(PlaceRef<'tcx, V>, mir::Local),
1241 // Store a direct return value to an operand local place.
1242 DirectOperand(mir::Local)