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(&mut self, mut bx: Bx) {
227 if self.fn_ty.c_variadic {
228 match self.va_list_ref {
230 bx.va_end(va_list.llval);
233 bug!("C-variadic function must have a `va_list_ref`");
237 if self.fn_ty.ret.layout.abi.is_uninhabited() {
238 // Functions with uninhabited return values are marked `noreturn`,
239 // so we should make sure that we never actually do.
244 let llval = match self.fn_ty.ret.mode {
245 PassMode::Ignore(IgnoreMode::Zst) | PassMode::Indirect(..) => {
250 PassMode::Ignore(IgnoreMode::CVarArgs) => {
251 bug!("C-variadic arguments should never be the return type");
254 PassMode::Direct(_) | PassMode::Pair(..) => {
256 self.codegen_consume(&mut bx, &mir::Place::RETURN_PLACE);
257 if let Ref(llval, _, align) = op.val {
258 bx.load(llval, align)
260 op.immediate_or_packed_pair(&mut bx)
264 PassMode::Cast(cast_ty) => {
265 let op = match self.locals[mir::RETURN_PLACE] {
266 LocalRef::Operand(Some(op)) => op,
267 LocalRef::Operand(None) => bug!("use of return before def"),
268 LocalRef::Place(cg_place) => {
270 val: Ref(cg_place.llval, None, cg_place.align),
271 layout: cg_place.layout
274 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
276 let llslot = match op.val {
277 Immediate(_) | Pair(..) => {
279 PlaceRef::alloca(&mut bx, self.fn_ty.ret.layout, "ret");
280 op.val.store(&mut bx, scratch);
283 Ref(llval, _, align) => {
284 assert_eq!(align, op.layout.align.abi,
285 "return place is unaligned!");
289 let addr = bx.pointercast(llslot, bx.type_ptr_to(
290 bx.cast_backend_type(&cast_ty)
292 bx.load(addr, self.fn_ty.ret.layout.align.abi)
299 fn codegen_drop_terminator<'b>(
301 helper: TerminatorCodegenHelper<'b, 'tcx>,
303 location: &mir::Place<'tcx>,
304 target: mir::BasicBlock,
305 unwind: Option<mir::BasicBlock>,
307 let ty = location.ty(self.mir, bx.tcx()).ty;
308 let ty = self.monomorphize(&ty);
309 let drop_fn = Instance::resolve_drop_in_place(bx.tcx(), ty);
311 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
312 // we don't actually need to drop anything.
313 helper.funclet_br(self, &mut bx, target);
317 let place = self.codegen_place(&mut bx, location);
319 let mut args = if let Some(llextra) = place.llextra {
320 args2 = [place.llval, llextra];
323 args1 = [place.llval];
326 let (drop_fn, fn_ty) = match ty.sty {
328 let sig = drop_fn.fn_sig(self.cx.tcx());
329 let sig = self.cx.tcx().normalize_erasing_late_bound_regions(
330 ty::ParamEnv::reveal_all(),
333 let fn_ty = FnType::new_vtable(&bx, sig, &[]);
334 let vtable = args[1];
336 (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_ty), fn_ty)
340 FnType::of_instance(&bx, &drop_fn))
343 helper.do_call(self, &mut bx, fn_ty, drop_fn, args,
344 Some((ReturnDest::Nothing, target)),
348 fn codegen_assert_terminator<'b>(
350 helper: TerminatorCodegenHelper<'b, 'tcx>,
352 terminator: &mir::Terminator<'tcx>,
353 cond: &mir::Operand<'tcx>,
355 msg: &mir::AssertMessage<'tcx>,
356 target: mir::BasicBlock,
357 cleanup: Option<mir::BasicBlock>,
359 let span = terminator.source_info.span;
360 let cond = self.codegen_operand(&mut bx, cond).immediate();
361 let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
363 // This case can currently arise only from functions marked
364 // with #[rustc_inherit_overflow_checks] and inlined from
365 // another crate (mostly core::num generic/#[inline] fns),
366 // while the current crate doesn't use overflow checks.
367 // NOTE: Unlike binops, negation doesn't have its own
368 // checked operation, just a comparison with the minimum
369 // value, so we have to check for the assert message.
370 if !bx.check_overflow() {
371 if let mir::interpret::InterpError::OverflowNeg = *msg {
372 const_cond = Some(expected);
376 // Don't codegen the panic block if success if known.
377 if const_cond == Some(expected) {
378 helper.funclet_br(self, &mut bx, target);
382 // Pass the condition through llvm.expect for branch hinting.
383 let cond = bx.expect(cond, expected);
385 // Create the failure block and the conditional branch to it.
386 let lltarget = helper.llblock(self, target);
387 let panic_block = self.new_block("panic");
389 bx.cond_br(cond, lltarget, panic_block.llbb());
391 bx.cond_br(cond, panic_block.llbb(), lltarget);
394 // After this point, bx is the block for the call to panic.
396 self.set_debug_loc(&mut bx, terminator.source_info);
398 // Get the location information.
399 let loc = bx.sess().source_map().lookup_char_pos(span.lo());
400 let filename = LocalInternedString::intern(&loc.file.name.to_string());
401 let line = bx.const_u32(loc.line as u32);
402 let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
404 // Put together the arguments to the panic entry point.
405 let (lang_item, args) = match *msg {
406 InterpError::BoundsCheck { ref len, ref index } => {
407 let len = self.codegen_operand(&mut bx, len).immediate();
408 let index = self.codegen_operand(&mut bx, index).immediate();
410 let file_line_col = bx.static_panic_msg(
415 "panic_bounds_check_loc",
417 (lang_items::PanicBoundsCheckFnLangItem,
418 vec![file_line_col, index, len])
421 let str = msg.description();
422 let msg_str = LocalInternedString::intern(str);
423 let msg_file_line_col = bx.static_panic_msg(
430 (lang_items::PanicFnLangItem,
431 vec![msg_file_line_col])
435 // Obtain the panic entry point.
436 let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
437 let instance = ty::Instance::mono(bx.tcx(), def_id);
438 let fn_ty = FnType::of_instance(&bx, &instance);
439 let llfn = bx.get_fn(instance);
441 // Codegen the actual panic invoke/call.
442 helper.do_call(self, &mut bx, fn_ty, llfn, &args, None, cleanup);
445 fn codegen_call_terminator<'b>(
447 helper: TerminatorCodegenHelper<'b, 'tcx>,
449 terminator: &mir::Terminator<'tcx>,
450 func: &mir::Operand<'tcx>,
451 args: &Vec<mir::Operand<'tcx>>,
452 destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
453 cleanup: Option<mir::BasicBlock>,
455 let span = terminator.source_info.span;
456 // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
457 let callee = self.codegen_operand(&mut bx, func);
459 let (instance, mut llfn) = match callee.layout.ty.sty {
460 ty::FnDef(def_id, substs) => {
461 (Some(ty::Instance::resolve(bx.tcx(),
462 ty::ParamEnv::reveal_all(),
468 (None, Some(callee.immediate()))
470 _ => bug!("{} is not callable", callee.layout.ty),
472 let def = instance.map(|i| i.def);
473 let sig = callee.layout.ty.fn_sig(bx.tcx());
474 let sig = bx.tcx().normalize_erasing_late_bound_regions(
475 ty::ParamEnv::reveal_all(),
480 // Handle intrinsics old codegen wants Expr's for, ourselves.
481 let intrinsic = match def {
482 Some(ty::InstanceDef::Intrinsic(def_id)) =>
483 Some(bx.tcx().item_name(def_id).as_str()),
486 let intrinsic = intrinsic.as_ref().map(|s| &s[..]);
488 if intrinsic == Some("transmute") {
489 if let Some(destination_ref) = destination.as_ref() {
490 let &(ref dest, target) = destination_ref;
491 self.codegen_transmute(&mut bx, &args[0], dest);
492 helper.funclet_br(self, &mut bx, target);
494 // If we are trying to transmute to an uninhabited type,
495 // it is likely there is no allotted destination. In fact,
496 // transmuting to an uninhabited type is UB, which means
497 // we can do what we like. Here, we declare that transmuting
498 // into an uninhabited type is impossible, so anything following
499 // it must be unreachable.
500 assert_eq!(bx.layout_of(sig.output()).abi, layout::Abi::Uninhabited);
506 // The "spoofed" `VaList` added to a C-variadic functions signature
507 // should not be included in the `extra_args` calculation.
508 let extra_args_start_idx = sig.inputs().len() - if sig.c_variadic { 1 } else { 0 };
509 let extra_args = &args[extra_args_start_idx..];
510 let extra_args = extra_args.iter().map(|op_arg| {
511 let op_ty = op_arg.ty(self.mir, bx.tcx());
512 self.monomorphize(&op_ty)
513 }).collect::<Vec<_>>();
515 let fn_ty = match def {
516 Some(ty::InstanceDef::Virtual(..)) => {
517 FnType::new_vtable(&bx, sig, &extra_args)
519 Some(ty::InstanceDef::DropGlue(_, None)) => {
520 // Empty drop glue; a no-op.
521 let &(_, target) = destination.as_ref().unwrap();
522 helper.funclet_br(self, &mut bx, target);
525 _ => FnType::new(&bx, sig, &extra_args)
528 // Emit a panic or a no-op for `panic_if_uninhabited`.
529 if intrinsic == Some("panic_if_uninhabited") {
530 let ty = instance.unwrap().substs.type_at(0);
531 let layout = bx.layout_of(ty);
532 if layout.abi.is_uninhabited() {
533 let loc = bx.sess().source_map().lookup_char_pos(span.lo());
534 let filename = LocalInternedString::intern(&loc.file.name.to_string());
535 let line = bx.const_u32(loc.line as u32);
536 let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
539 "Attempted to instantiate uninhabited type {}",
542 let msg_str = LocalInternedString::intern(&str);
543 let msg_file_line_col = bx.static_panic_msg(
551 // Obtain the panic entry point.
553 common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
554 let instance = ty::Instance::mono(bx.tcx(), def_id);
555 let fn_ty = FnType::of_instance(&bx, &instance);
556 let llfn = bx.get_fn(instance);
558 // Codegen the actual panic invoke/call.
564 &[msg_file_line_col],
565 destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
570 helper.funclet_br(self, &mut bx, destination.as_ref().unwrap().1)
575 // The arguments we'll be passing. Plus one to account for outptr, if used.
576 let arg_count = fn_ty.args.len() + fn_ty.ret.is_indirect() as usize;
577 let mut llargs = Vec::with_capacity(arg_count);
579 // Prepare the return value destination
580 let ret_dest = if let Some((ref dest, _)) = *destination {
581 let is_intrinsic = intrinsic.is_some();
582 self.make_return_dest(&mut bx, dest, &fn_ty.ret, &mut llargs,
588 if intrinsic.is_some() && intrinsic != Some("drop_in_place") {
589 let dest = match ret_dest {
590 _ if fn_ty.ret.is_indirect() => llargs[0],
591 ReturnDest::Nothing =>
592 bx.const_undef(bx.type_ptr_to(bx.memory_ty(&fn_ty.ret))),
593 ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) =>
595 ReturnDest::DirectOperand(_) =>
596 bug!("Cannot use direct operand with an intrinsic call"),
599 let args: Vec<_> = args.iter().enumerate().map(|(i, arg)| {
600 // The indices passed to simd_shuffle* in the
601 // third argument must be constant. This is
602 // checked by const-qualification, which also
603 // promotes any complex rvalues to constants.
604 if i == 2 && intrinsic.unwrap().starts_with("simd_shuffle") {
606 // The shuffle array argument is usually not an explicit constant,
607 // but specified directly in the code. This means it gets promoted
608 // and we can then extract the value by evaluating the promoted.
612 box Static { kind: StaticKind::Promoted(promoted), ty }
619 box Static { kind: StaticKind::Promoted(promoted), ty }
623 let param_env = ty::ParamEnv::reveal_all();
624 let cid = mir::interpret::GlobalId {
625 instance: self.instance,
626 promoted: Some(promoted),
628 let c = bx.tcx().const_eval(param_env.and(cid));
629 let (llval, ty) = self.simd_shuffle_indices(
631 terminator.source_info.span,
636 val: Immediate(llval),
637 layout: bx.layout_of(ty),
641 mir::Operand::Copy(_) |
642 mir::Operand::Move(_) => {
643 span_bug!(span, "shuffle indices must be constant");
645 mir::Operand::Constant(ref constant) => {
646 let c = self.eval_mir_constant(constant);
647 let (llval, ty) = self.simd_shuffle_indices(
654 val: Immediate(llval),
655 layout: bx.layout_of(ty)
661 self.codegen_operand(&mut bx, arg)
665 let callee_ty = instance.as_ref().unwrap().ty(bx.tcx());
666 bx.codegen_intrinsic_call(callee_ty, &fn_ty, &args, dest,
667 terminator.source_info.span);
669 if let ReturnDest::IndirectOperand(dst, _) = ret_dest {
670 self.store_return(&mut bx, ret_dest, &fn_ty.ret, dst.llval);
673 if let Some((_, target)) = *destination {
674 helper.funclet_br(self, &mut bx, target);
682 // Split the rust-call tupled arguments off.
683 let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() {
684 let (tup, args) = args.split_last().unwrap();
690 // Useful determining if the current argument is the "spoofed" `VaList`
691 let last_arg_idx = if sig.inputs().is_empty() {
694 Some(sig.inputs().len() - 1)
696 'make_args: for (i, arg) in first_args.iter().enumerate() {
697 // If this is a C-variadic function the function signature contains
698 // an "spoofed" `VaList`. This argument is ignored, but we need to
699 // populate it with a dummy operand so that the users real arguments
700 // are not overwritten.
701 let i = if sig.c_variadic && last_arg_idx.map(|x| i >= x).unwrap_or(false) {
702 if i + 1 < fn_ty.args.len() {
710 let mut op = self.codegen_operand(&mut bx, arg);
712 if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) {
713 if let Pair(..) = op.val {
714 // In the case of Rc<Self>, we need to explicitly pass a
715 // *mut RcBox<Self> with a Scalar (not ScalarPair) ABI. This is a hack
716 // that is understood elsewhere in the compiler as a method on
718 // To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
719 // we get a value of a built-in pointer type
720 'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
721 && !op.layout.ty.is_region_ptr()
723 'iter_fields: for i in 0..op.layout.fields.count() {
724 let field = op.extract_field(&mut bx, i);
725 if !field.layout.is_zst() {
726 // we found the one non-zero-sized field that is allowed
727 // now find *its* non-zero-sized field, or stop if it's a
730 continue 'descend_newtypes
734 span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
737 // now that we have `*dyn Trait` or `&dyn Trait`, split it up into its
738 // data pointer and vtable. Look up the method in the vtable, and pass
739 // the data pointer as the first argument
741 Pair(data_ptr, meta) => {
742 llfn = Some(meth::VirtualIndex::from_index(idx)
743 .get_fn(&mut bx, meta, &fn_ty));
744 llargs.push(data_ptr);
747 other => bug!("expected a Pair, got {:?}", other),
749 } else if let Ref(data_ptr, Some(meta), _) = op.val {
750 // by-value dynamic dispatch
751 llfn = Some(meth::VirtualIndex::from_index(idx)
752 .get_fn(&mut bx, meta, &fn_ty));
753 llargs.push(data_ptr);
756 span_bug!(span, "can't codegen a virtual call on {:?}", op);
760 // The callee needs to own the argument memory if we pass it
761 // by-ref, so make a local copy of non-immediate constants.
762 match (arg, op.val) {
763 (&mir::Operand::Copy(_), Ref(_, None, _)) |
764 (&mir::Operand::Constant(_), Ref(_, None, _)) => {
765 let tmp = PlaceRef::alloca(&mut bx, op.layout, "const");
766 op.val.store(&mut bx, tmp);
767 op.val = Ref(tmp.llval, None, tmp.align);
772 self.codegen_argument(&mut bx, op, &mut llargs, &fn_ty.args[i]);
774 if let Some(tup) = untuple {
775 self.codegen_arguments_untupled(&mut bx, tup, &mut llargs,
776 &fn_ty.args[first_args.len()..])
779 let fn_ptr = match (llfn, instance) {
780 (Some(llfn), _) => llfn,
781 (None, Some(instance)) => bx.get_fn(instance),
782 _ => span_bug!(span, "no llfn for call"),
785 helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs,
786 destination.as_ref().map(|&(_, target)| (ret_dest, target)),
791 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
792 pub fn codegen_block(
796 let mut bx = self.build_block(bb);
797 let data = &self.mir[bb];
799 debug!("codegen_block({:?}={:?})", bb, data);
801 for statement in &data.statements {
802 bx = self.codegen_statement(bx, statement);
805 self.codegen_terminator(bx, bb, data.terminator());
808 fn codegen_terminator(
812 terminator: &mir::Terminator<'tcx>
814 debug!("codegen_terminator: {:?}", terminator);
816 // Create the cleanup bundle, if needed.
817 let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
818 let helper = TerminatorCodegenHelper {
819 bb: &bb, terminator, funclet_bb
822 self.set_debug_loc(&mut bx, terminator.source_info);
823 match terminator.kind {
824 mir::TerminatorKind::Resume => {
825 self.codegen_resume_terminator(helper, bx)
828 mir::TerminatorKind::Abort => {
833 mir::TerminatorKind::Goto { target } => {
834 helper.funclet_br(self, &mut bx, target);
837 mir::TerminatorKind::SwitchInt {
838 ref discr, switch_ty, ref values, ref targets
840 self.codegen_switchint_terminator(helper, bx, discr, switch_ty,
844 mir::TerminatorKind::Return => {
845 self.codegen_return_terminator(bx);
848 mir::TerminatorKind::Unreachable => {
852 mir::TerminatorKind::Drop { ref location, target, unwind } => {
853 self.codegen_drop_terminator(helper, bx, location, target, unwind);
856 mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
857 self.codegen_assert_terminator(helper, bx, terminator, cond,
858 expected, msg, target, cleanup);
861 mir::TerminatorKind::DropAndReplace { .. } => {
862 bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
865 mir::TerminatorKind::Call {
872 self.codegen_call_terminator(helper, bx, terminator, func,
873 args, destination, cleanup);
875 mir::TerminatorKind::GeneratorDrop |
876 mir::TerminatorKind::Yield { .. } => bug!("generator ops in codegen"),
877 mir::TerminatorKind::FalseEdges { .. } |
878 mir::TerminatorKind::FalseUnwind { .. } => bug!("borrowck false edges in codegen"),
885 op: OperandRef<'tcx, Bx::Value>,
886 llargs: &mut Vec<Bx::Value>,
887 arg: &ArgType<'tcx, Ty<'tcx>>
889 // Fill padding with undef value, where applicable.
890 if let Some(ty) = arg.pad {
891 llargs.push(bx.const_undef(bx.reg_backend_type(&ty)))
898 if let PassMode::Pair(..) = arg.mode {
905 _ => bug!("codegen_argument: {:?} invalid for pair argument", op)
907 } else if arg.is_unsized_indirect() {
909 Ref(a, Some(b), _) => {
914 _ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op)
918 // Force by-ref if we have to load through a cast pointer.
919 let (mut llval, align, by_ref) = match op.val {
920 Immediate(_) | Pair(..) => {
922 PassMode::Indirect(..) | PassMode::Cast(_) => {
923 let scratch = PlaceRef::alloca(bx, arg.layout, "arg");
924 op.val.store(bx, scratch);
925 (scratch.llval, scratch.align, true)
928 (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false)
932 Ref(llval, _, align) => {
933 if arg.is_indirect() && align < arg.layout.align.abi {
934 // `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I
935 // think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't
936 // have scary latent bugs around.
938 let scratch = PlaceRef::alloca(bx, arg.layout, "arg");
939 base::memcpy_ty(bx, scratch.llval, scratch.align, llval, align,
940 op.layout, MemFlags::empty());
941 (scratch.llval, scratch.align, true)
948 if by_ref && !arg.is_indirect() {
949 // Have to load the argument, maybe while casting it.
950 if let PassMode::Cast(ty) = arg.mode {
951 let addr = bx.pointercast(llval, bx.type_ptr_to(
952 bx.cast_backend_type(&ty))
954 llval = bx.load(addr, align.min(arg.layout.align.abi));
956 // We can't use `PlaceRef::load` here because the argument
957 // may have a type we don't treat as immediate, but the ABI
958 // used for this call is passing it by-value. In that case,
959 // the load would just produce `OperandValue::Ref` instead
960 // of the `OperandValue::Immediate` we need for the call.
961 llval = bx.load(llval, align);
962 if let layout::Abi::Scalar(ref scalar) = arg.layout.abi {
963 if scalar.is_bool() {
964 bx.range_metadata(llval, 0..2);
967 // We store bools as `i8` so we need to truncate to `i1`.
968 llval = base::to_immediate(bx, llval, arg.layout);
975 fn codegen_arguments_untupled(
978 operand: &mir::Operand<'tcx>,
979 llargs: &mut Vec<Bx::Value>,
980 args: &[ArgType<'tcx, Ty<'tcx>>]
982 let tuple = self.codegen_operand(bx, operand);
984 // Handle both by-ref and immediate tuples.
985 if let Ref(llval, None, align) = tuple.val {
986 let tuple_ptr = PlaceRef::new_sized(llval, tuple.layout, align);
987 for i in 0..tuple.layout.fields.count() {
988 let field_ptr = tuple_ptr.project_field(bx, i);
989 let field = bx.load_operand(field_ptr);
990 self.codegen_argument(bx, field, llargs, &args[i]);
992 } else if let Ref(_, Some(_), _) = tuple.val {
993 bug!("closure arguments must be sized")
995 // If the tuple is immediate, the elements are as well.
996 for i in 0..tuple.layout.fields.count() {
997 let op = tuple.extract_field(bx, i);
998 self.codegen_argument(bx, op, llargs, &args[i]);
1003 fn get_personality_slot(
1006 ) -> PlaceRef<'tcx, Bx::Value> {
1008 if let Some(slot) = self.personality_slot {
1011 let layout = cx.layout_of(cx.tcx().intern_tup(&[
1012 cx.tcx().mk_mut_ptr(cx.tcx().types.u8),
1015 let slot = PlaceRef::alloca(bx, layout, "personalityslot");
1016 self.personality_slot = Some(slot);
1021 /// Returns the landing-pad wrapper around the given basic block.
1023 /// No-op in MSVC SEH scheme.
1026 target_bb: mir::BasicBlock
1027 ) -> Bx::BasicBlock {
1028 if let Some(block) = self.landing_pads[target_bb] {
1032 let block = self.blocks[target_bb];
1033 let landing_pad = self.landing_pad_uncached(block);
1034 self.landing_pads[target_bb] = Some(landing_pad);
1038 fn landing_pad_uncached(
1040 target_bb: Bx::BasicBlock
1041 ) -> Bx::BasicBlock {
1042 if base::wants_msvc_seh(self.cx.sess()) {
1043 span_bug!(self.mir.span, "landing pad was not inserted?")
1046 let mut bx = self.new_block("cleanup");
1048 let llpersonality = self.cx.eh_personality();
1049 let llretty = self.landing_pad_type();
1050 let lp = bx.landing_pad(llretty, llpersonality, 1);
1053 let slot = self.get_personality_slot(&mut bx);
1054 slot.storage_live(&mut bx);
1055 Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot);
1061 fn landing_pad_type(&self) -> Bx::Type {
1063 cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
1066 fn unreachable_block(
1068 ) -> Bx::BasicBlock {
1069 self.unreachable_block.unwrap_or_else(|| {
1070 let mut bx = self.new_block("unreachable");
1072 self.unreachable_block = Some(bx.llbb());
1077 pub fn new_block(&self, name: &str) -> Bx {
1078 Bx::new_block(self.cx, self.llfn, name)
1085 let mut bx = Bx::with_cx(self.cx);
1086 bx.position_at_end(self.blocks[bb]);
1090 fn make_return_dest(
1093 dest: &mir::Place<'tcx>,
1094 fn_ret: &ArgType<'tcx, Ty<'tcx>>,
1095 llargs: &mut Vec<Bx::Value>, is_intrinsic: bool
1096 ) -> ReturnDest<'tcx, Bx::Value> {
1097 // If the return is ignored, we can just return a do-nothing `ReturnDest`.
1098 if fn_ret.is_ignore() {
1099 return ReturnDest::Nothing;
1101 let dest = if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dest {
1102 match self.locals[index] {
1103 LocalRef::Place(dest) => dest,
1104 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
1105 LocalRef::Operand(None) => {
1106 // Handle temporary places, specifically `Operand` ones, as
1107 // they don't have `alloca`s.
1108 return if fn_ret.is_indirect() {
1109 // Odd, but possible, case, we have an operand temporary,
1110 // but the calling convention has an indirect return.
1111 let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret");
1112 tmp.storage_live(bx);
1113 llargs.push(tmp.llval);
1114 ReturnDest::IndirectOperand(tmp, index)
1115 } else if is_intrinsic {
1116 // Currently, intrinsics always need a location to store
1117 // the result, so we create a temporary `alloca` for the
1119 let tmp = PlaceRef::alloca(bx, fn_ret.layout, "tmp_ret");
1120 tmp.storage_live(bx);
1121 ReturnDest::IndirectOperand(tmp, index)
1123 ReturnDest::DirectOperand(index)
1126 LocalRef::Operand(Some(_)) => {
1127 bug!("place local already assigned to");
1131 self.codegen_place(bx, dest)
1133 if fn_ret.is_indirect() {
1134 if dest.align < dest.layout.align.abi {
1135 // Currently, MIR code generation does not create calls
1136 // that store directly to fields of packed structs (in
1137 // fact, the calls it creates write only to temps).
1139 // If someone changes that, please update this code path
1140 // to create a temporary.
1141 span_bug!(self.mir.span, "can't directly store to unaligned value");
1143 llargs.push(dest.llval);
1146 ReturnDest::Store(dest)
1150 fn codegen_transmute(
1153 src: &mir::Operand<'tcx>,
1154 dst: &mir::Place<'tcx>
1156 if let mir::Place::Base(mir::PlaceBase::Local(index)) = *dst {
1157 match self.locals[index] {
1158 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
1159 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
1160 LocalRef::Operand(None) => {
1161 let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst));
1162 assert!(!dst_layout.ty.has_erasable_regions());
1163 let place = PlaceRef::alloca(bx, dst_layout, "transmute_temp");
1164 place.storage_live(bx);
1165 self.codegen_transmute_into(bx, src, place);
1166 let op = bx.load_operand(place);
1167 place.storage_dead(bx);
1168 self.locals[index] = LocalRef::Operand(Some(op));
1170 LocalRef::Operand(Some(op)) => {
1171 assert!(op.layout.is_zst(),
1172 "assigning to initialized SSAtemp");
1176 let dst = self.codegen_place(bx, dst);
1177 self.codegen_transmute_into(bx, src, dst);
1181 fn codegen_transmute_into(
1184 src: &mir::Operand<'tcx>,
1185 dst: PlaceRef<'tcx, Bx::Value>
1187 let src = self.codegen_operand(bx, src);
1188 let llty = bx.backend_type(src.layout);
1189 let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty));
1190 let align = src.layout.align.abi.min(dst.align);
1191 src.val.store(bx, PlaceRef::new_sized(cast_ptr, src.layout, align));
1195 // Stores the return value of a function call into it's final location.
1199 dest: ReturnDest<'tcx, Bx::Value>,
1200 ret_ty: &ArgType<'tcx, Ty<'tcx>>,
1203 use self::ReturnDest::*;
1207 Store(dst) => bx.store_arg_ty(&ret_ty, llval, dst),
1208 IndirectOperand(tmp, index) => {
1209 let op = bx.load_operand(tmp);
1210 tmp.storage_dead(bx);
1211 self.locals[index] = LocalRef::Operand(Some(op));
1213 DirectOperand(index) => {
1214 // If there is a cast, we have to store and reload.
1215 let op = if let PassMode::Cast(_) = ret_ty.mode {
1216 let tmp = PlaceRef::alloca(bx, ret_ty.layout, "tmp_ret");
1217 tmp.storage_live(bx);
1218 bx.store_arg_ty(&ret_ty, llval, tmp);
1219 let op = bx.load_operand(tmp);
1220 tmp.storage_dead(bx);
1223 OperandRef::from_immediate_or_packed_pair(bx, llval, ret_ty.layout)
1225 self.locals[index] = LocalRef::Operand(Some(op));
1231 enum ReturnDest<'tcx, V> {
1232 // Do nothing; the return value is indirect or ignored.
1234 // Store the return value to the pointer.
1235 Store(PlaceRef<'tcx, V>),
1236 // Store an indirect return value to an operand local place.
1237 IndirectOperand(PlaceRef<'tcx, V>, mir::Local),
1238 // Store a direct return value to an operand local place.
1239 DirectOperand(mir::Local)