1 use super::operand::OperandRef;
2 use super::operand::OperandValue::{Immediate, Pair, Ref};
3 use super::place::PlaceRef;
4 use super::{FunctionCx, LocalRef};
7 use crate::common::{self, IntPredicate};
13 use rustc_hir::lang_items;
14 use rustc_index::vec::Idx;
15 use rustc_middle::mir;
16 use rustc_middle::mir::interpret::{AllocId, ConstValue, Pointer, Scalar};
17 use rustc_middle::mir::AssertKind;
18 use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
19 use rustc_middle::ty::{self, Instance, Ty, TypeFoldable};
20 use rustc_span::{source_map::Span, symbol::Symbol};
21 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
22 use rustc_target::abi::{self, LayoutOf};
23 use rustc_target::spec::abi::Abi;
27 /// Used by `FunctionCx::codegen_terminator` for emitting common patterns
28 /// e.g., creating a basic block, calling a function, etc.
29 struct TerminatorCodegenHelper<'tcx> {
31 terminator: &'tcx mir::Terminator<'tcx>,
32 funclet_bb: Option<mir::BasicBlock>,
35 impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
36 /// Returns the associated funclet from `FunctionCx::funclets` for the
37 /// `funclet_bb` member if it is not `None`.
38 fn funclet<'b, Bx: BuilderMethods<'a, 'tcx>>(
40 fx: &'b mut FunctionCx<'a, 'tcx, Bx>,
41 ) -> Option<&'b Bx::Funclet> {
42 match self.funclet_bb {
43 Some(funcl) => fx.funclets[funcl].as_ref(),
48 fn lltarget<Bx: BuilderMethods<'a, 'tcx>>(
50 fx: &mut FunctionCx<'a, 'tcx, Bx>,
51 target: mir::BasicBlock,
52 ) -> (Bx::BasicBlock, bool) {
53 let span = self.terminator.source_info.span;
54 let lltarget = fx.blocks[target];
55 let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
56 match (self.funclet_bb, target_funclet) {
57 (None, None) => (lltarget, false),
58 (Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) => {
61 // jump *into* cleanup - need a landing pad if GNU
62 (None, Some(_)) => (fx.landing_pad_to(target), false),
63 (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
64 (Some(_), Some(_)) => (fx.landing_pad_to(target), true),
68 /// Create a basic block.
69 fn llblock<Bx: BuilderMethods<'a, 'tcx>>(
71 fx: &mut FunctionCx<'a, 'tcx, Bx>,
72 target: mir::BasicBlock,
74 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
76 // MSVC cross-funclet jump - need a trampoline
78 debug!("llblock: creating cleanup trampoline for {:?}", target);
79 let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
80 let mut trampoline = fx.new_block(name);
81 trampoline.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
88 fn funclet_br<Bx: BuilderMethods<'a, 'tcx>>(
90 fx: &mut FunctionCx<'a, 'tcx, Bx>,
92 target: mir::BasicBlock,
94 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
96 // micro-optimization: generate a `ret` rather than a jump
98 bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
104 /// Call `fn_ptr` of `fn_abi` with the arguments `llargs`, the optional
105 /// return destination `destination` and the cleanup function `cleanup`.
106 fn do_call<Bx: BuilderMethods<'a, 'tcx>>(
108 fx: &mut FunctionCx<'a, 'tcx, Bx>,
110 fn_abi: FnAbi<'tcx, Ty<'tcx>>,
112 llargs: &[Bx::Value],
113 destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>,
114 cleanup: Option<mir::BasicBlock>,
116 // If there is a cleanup block and the function we're calling can unwind, then
117 // do an invoke, otherwise do a call.
118 if let Some(cleanup) = cleanup.filter(|_| fn_abi.can_unwind) {
119 let ret_bx = if let Some((_, target)) = destination {
122 fx.unreachable_block()
125 bx.invoke(fn_ptr, &llargs, ret_bx, self.llblock(fx, cleanup), self.funclet(fx));
126 bx.apply_attrs_callsite(&fn_abi, invokeret);
128 if let Some((ret_dest, target)) = destination {
129 let mut ret_bx = fx.build_block(target);
130 fx.set_debug_loc(&mut ret_bx, self.terminator.source_info);
131 fx.store_return(&mut ret_bx, ret_dest, &fn_abi.ret, invokeret);
134 let llret = bx.call(fn_ptr, &llargs, self.funclet(fx));
135 bx.apply_attrs_callsite(&fn_abi, llret);
136 if fx.mir[self.bb].is_cleanup {
137 // Cleanup is always the cold path. Don't inline
138 // drop glue. Also, when there is a deeply-nested
139 // struct, there are "symmetry" issues that cause
140 // exponential inlining - see issue #41696.
141 bx.do_not_inline(llret);
144 if let Some((ret_dest, target)) = destination {
145 fx.store_return(bx, ret_dest, &fn_abi.ret, llret);
146 self.funclet_br(fx, bx, target);
153 // Generate sideeffect intrinsic if jumping to any of the targets can form
155 fn maybe_sideeffect<Bx: BuilderMethods<'a, 'tcx>>(
157 mir: &'tcx mir::Body<'tcx>,
159 targets: &[mir::BasicBlock],
161 if bx.tcx().sess.opts.debugging_opts.insert_sideeffect {
162 if targets.iter().any(|&target| {
164 && target.start_location().is_predecessor_of(self.bb.start_location(), mir)
172 /// Codegen implementations for some terminator variants.
173 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
174 /// Generates code for a `Resume` terminator.
175 fn codegen_resume_terminator(&mut self, helper: TerminatorCodegenHelper<'tcx>, mut bx: Bx) {
176 if let Some(funclet) = helper.funclet(self) {
177 bx.cleanup_ret(funclet, None);
179 let slot = self.get_personality_slot(&mut bx);
180 let lp0 = slot.project_field(&mut bx, 0);
181 let lp0 = bx.load_operand(lp0).immediate();
182 let lp1 = slot.project_field(&mut bx, 1);
183 let lp1 = bx.load_operand(lp1).immediate();
184 slot.storage_dead(&mut bx);
186 let mut lp = bx.const_undef(self.landing_pad_type());
187 lp = bx.insert_value(lp, lp0, 0);
188 lp = bx.insert_value(lp, lp1, 1);
193 fn codegen_switchint_terminator(
195 helper: TerminatorCodegenHelper<'tcx>,
197 discr: &mir::Operand<'tcx>,
199 values: &Cow<'tcx, [u128]>,
200 targets: &Vec<mir::BasicBlock>,
202 let discr = self.codegen_operand(&mut bx, &discr);
203 if targets.len() == 2 {
204 // If there are two targets, emit br instead of switch
205 let lltrue = helper.llblock(self, targets[0]);
206 let llfalse = helper.llblock(self, targets[1]);
207 if switch_ty == bx.tcx().types.bool {
208 helper.maybe_sideeffect(self.mir, &mut bx, targets.as_slice());
209 // Don't generate trivial icmps when switching on bool
210 if let [0] = values[..] {
211 bx.cond_br(discr.immediate(), llfalse, lltrue);
213 assert_eq!(&values[..], &[1]);
214 bx.cond_br(discr.immediate(), lltrue, llfalse);
217 let switch_llty = bx.immediate_backend_type(bx.layout_of(switch_ty));
218 let llval = bx.const_uint_big(switch_llty, values[0]);
219 let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval);
220 helper.maybe_sideeffect(self.mir, &mut bx, targets.as_slice());
221 bx.cond_br(cmp, lltrue, llfalse);
224 helper.maybe_sideeffect(self.mir, &mut bx, targets.as_slice());
225 let (otherwise, targets) = targets.split_last().unwrap();
228 helper.llblock(self, *otherwise),
232 .map(|(&value, target)| (value, helper.llblock(self, *target))),
237 fn codegen_return_terminator(&mut self, mut bx: Bx) {
238 // Call `va_end` if this is the definition of a C-variadic function.
239 if self.fn_abi.c_variadic {
240 // The `VaList` "spoofed" argument is just after all the real arguments.
241 let va_list_arg_idx = self.fn_abi.args.len();
242 match self.locals[mir::Local::new(1 + va_list_arg_idx)] {
243 LocalRef::Place(va_list) => {
244 bx.va_end(va_list.llval);
246 _ => bug!("C-variadic function must have a `VaList` place"),
249 if self.fn_abi.ret.layout.abi.is_uninhabited() {
250 // Functions with uninhabited return values are marked `noreturn`,
251 // so we should make sure that we never actually do.
252 // We play it safe by using a well-defined `abort`, but we could go for immediate UB
253 // if that turns out to be helpful.
255 // `abort` does not terminate the block, so we still need to generate
256 // an `unreachable` terminator after it.
260 let llval = match self.fn_abi.ret.mode {
261 PassMode::Ignore | PassMode::Indirect(..) => {
266 PassMode::Direct(_) | PassMode::Pair(..) => {
267 let op = self.codegen_consume(&mut bx, mir::Place::return_place().as_ref());
268 if let Ref(llval, _, align) = op.val {
269 bx.load(llval, align)
271 op.immediate_or_packed_pair(&mut bx)
275 PassMode::Cast(cast_ty) => {
276 let op = match self.locals[mir::RETURN_PLACE] {
277 LocalRef::Operand(Some(op)) => op,
278 LocalRef::Operand(None) => bug!("use of return before def"),
279 LocalRef::Place(cg_place) => OperandRef {
280 val: Ref(cg_place.llval, None, cg_place.align),
281 layout: cg_place.layout,
283 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
285 let llslot = match op.val {
286 Immediate(_) | Pair(..) => {
287 let scratch = PlaceRef::alloca(&mut bx, self.fn_abi.ret.layout);
288 op.val.store(&mut bx, scratch);
291 Ref(llval, _, align) => {
292 assert_eq!(align, op.layout.align.abi, "return place is unaligned!");
296 let addr = bx.pointercast(llslot, bx.type_ptr_to(bx.cast_backend_type(&cast_ty)));
297 bx.load(addr, self.fn_abi.ret.layout.align.abi)
303 fn codegen_drop_terminator(
305 helper: TerminatorCodegenHelper<'tcx>,
307 location: mir::Place<'tcx>,
308 target: mir::BasicBlock,
309 unwind: Option<mir::BasicBlock>,
311 let ty = location.ty(self.mir, bx.tcx()).ty;
312 let ty = self.monomorphize(&ty);
313 let drop_fn = Instance::resolve_drop_in_place(bx.tcx(), ty);
315 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
316 // we don't actually need to drop anything.
317 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
318 helper.funclet_br(self, &mut bx, target);
322 let place = self.codegen_place(&mut bx, location.as_ref());
324 let mut args = if let Some(llextra) = place.llextra {
325 args2 = [place.llval, llextra];
328 args1 = [place.llval];
331 let (drop_fn, fn_abi) = match ty.kind {
332 // FIXME(eddyb) perhaps move some of this logic into
333 // `Instance::resolve_drop_in_place`?
335 let virtual_drop = Instance {
336 def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
337 substs: drop_fn.substs,
339 let fn_abi = FnAbi::of_instance(&bx, virtual_drop, &[]);
340 let vtable = args[1];
342 (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_abi), fn_abi)
344 _ => (bx.get_fn_addr(drop_fn), FnAbi::of_instance(&bx, drop_fn, &[])),
346 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
353 Some((ReturnDest::Nothing, target)),
358 fn codegen_assert_terminator(
360 helper: TerminatorCodegenHelper<'tcx>,
362 terminator: &mir::Terminator<'tcx>,
363 cond: &mir::Operand<'tcx>,
365 msg: &mir::AssertMessage<'tcx>,
366 target: mir::BasicBlock,
367 cleanup: Option<mir::BasicBlock>,
369 let span = terminator.source_info.span;
370 let cond = self.codegen_operand(&mut bx, cond).immediate();
371 let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
373 // This case can currently arise only from functions marked
374 // with #[rustc_inherit_overflow_checks] and inlined from
375 // another crate (mostly core::num generic/#[inline] fns),
376 // while the current crate doesn't use overflow checks.
377 // NOTE: Unlike binops, negation doesn't have its own
378 // checked operation, just a comparison with the minimum
379 // value, so we have to check for the assert message.
380 if !bx.check_overflow() {
381 if let AssertKind::OverflowNeg = *msg {
382 const_cond = Some(expected);
386 // Don't codegen the panic block if success if known.
387 if const_cond == Some(expected) {
388 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
389 helper.funclet_br(self, &mut bx, target);
393 // Pass the condition through llvm.expect for branch hinting.
394 let cond = bx.expect(cond, expected);
396 // Create the failure block and the conditional branch to it.
397 let lltarget = helper.llblock(self, target);
398 let panic_block = self.new_block("panic");
399 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
401 bx.cond_br(cond, lltarget, panic_block.llbb());
403 bx.cond_br(cond, panic_block.llbb(), lltarget);
406 // After this point, bx is the block for the call to panic.
408 self.set_debug_loc(&mut bx, terminator.source_info);
410 // Get the location information.
411 let location = self.get_caller_location(&mut bx, span).immediate();
413 // Put together the arguments to the panic entry point.
414 let (lang_item, args) = match msg {
415 AssertKind::BoundsCheck { ref len, ref index } => {
416 let len = self.codegen_operand(&mut bx, len).immediate();
417 let index = self.codegen_operand(&mut bx, index).immediate();
418 // It's `fn panic_bounds_check(index: usize, len: usize)`,
419 // and `#[track_caller]` adds an implicit third argument.
420 (lang_items::PanicBoundsCheckFnLangItem, vec![index, len, location])
423 let msg_str = Symbol::intern(msg.description());
424 let msg = bx.const_str(msg_str);
425 // It's `pub fn panic(expr: &str)`, with the wide reference being passed
426 // as two arguments, and `#[track_caller]` adds an implicit third argument.
427 (lang_items::PanicFnLangItem, vec![msg.0, msg.1, location])
431 // Obtain the panic entry point.
432 let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
433 let instance = ty::Instance::mono(bx.tcx(), def_id);
434 let fn_abi = FnAbi::of_instance(&bx, instance, &[]);
435 let llfn = bx.get_fn_addr(instance);
437 // Codegen the actual panic invoke/call.
438 helper.do_call(self, &mut bx, fn_abi, llfn, &args, None, cleanup);
441 /// Returns `true` if this is indeed a panic intrinsic and codegen is done.
442 fn codegen_panic_intrinsic(
444 helper: &TerminatorCodegenHelper<'tcx>,
446 intrinsic: Option<&str>,
447 instance: Option<Instance<'tcx>>,
449 destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
450 cleanup: Option<mir::BasicBlock>,
452 // Emit a panic or a no-op for `assert_*` intrinsics.
453 // These are intrinsics that compile to panics so that we can get a message
454 // which mentions the offending type, even from a const context.
455 #[derive(Debug, PartialEq)]
456 enum AssertIntrinsic {
461 let panic_intrinsic = intrinsic.and_then(|i| match i {
462 // FIXME: Move to symbols instead of strings.
463 "assert_inhabited" => Some(AssertIntrinsic::Inhabited),
464 "assert_zero_valid" => Some(AssertIntrinsic::ZeroValid),
465 "assert_uninit_valid" => Some(AssertIntrinsic::UninitValid),
468 if let Some(intrinsic) = panic_intrinsic {
469 use AssertIntrinsic::*;
470 let ty = instance.unwrap().substs.type_at(0);
471 let layout = bx.layout_of(ty);
472 let do_panic = match intrinsic {
473 Inhabited => layout.abi.is_uninhabited(),
474 // We unwrap as the error type is `!`.
475 ZeroValid => !layout.might_permit_raw_init(bx, /*zero:*/ true).unwrap(),
476 // We unwrap as the error type is `!`.
477 UninitValid => !layout.might_permit_raw_init(bx, /*zero:*/ false).unwrap(),
480 let msg_str = if layout.abi.is_uninhabited() {
481 // Use this error even for the other intrinsics as it is more precise.
482 format!("attempted to instantiate uninhabited type `{}`", ty)
483 } else if intrinsic == ZeroValid {
484 format!("attempted to zero-initialize type `{}`, which is invalid", ty)
486 format!("attempted to leave type `{}` uninitialized, which is invalid", ty)
488 let msg = bx.const_str(Symbol::intern(&msg_str));
489 let location = self.get_caller_location(bx, span).immediate();
491 // Obtain the panic entry point.
492 // FIXME: dedup this with `codegen_assert_terminator` above.
494 common::langcall(bx.tcx(), Some(span), "", lang_items::PanicFnLangItem);
495 let instance = ty::Instance::mono(bx.tcx(), def_id);
496 let fn_abi = FnAbi::of_instance(bx, instance, &[]);
497 let llfn = bx.get_fn_addr(instance);
499 if let Some((_, target)) = destination.as_ref() {
500 helper.maybe_sideeffect(self.mir, bx, &[*target]);
502 // Codegen the actual panic invoke/call.
508 &[msg.0, msg.1, location],
509 destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
514 let target = destination.as_ref().unwrap().1;
515 helper.maybe_sideeffect(self.mir, bx, &[target]);
516 helper.funclet_br(self, bx, target)
524 fn codegen_call_terminator(
526 helper: TerminatorCodegenHelper<'tcx>,
528 terminator: &mir::Terminator<'tcx>,
529 func: &mir::Operand<'tcx>,
530 args: &Vec<mir::Operand<'tcx>>,
531 destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
532 cleanup: Option<mir::BasicBlock>,
535 let span = terminator.source_info.span;
536 // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
537 let callee = self.codegen_operand(&mut bx, func);
539 let (instance, mut llfn) = match callee.layout.ty.kind {
540 ty::FnDef(def_id, substs) => (
542 ty::Instance::resolve(bx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs)
548 ty::FnPtr(_) => (None, Some(callee.immediate())),
549 _ => bug!("{} is not callable", callee.layout.ty),
551 let def = instance.map(|i| i.def);
553 if let Some(ty::InstanceDef::DropGlue(_, None)) = def {
554 // Empty drop glue; a no-op.
555 let &(_, target) = destination.as_ref().unwrap();
556 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
557 helper.funclet_br(self, &mut bx, target);
561 // FIXME(eddyb) avoid computing this if possible, when `instance` is
562 // available - right now `sig` is only needed for getting the `abi`
563 // and figuring out how many extra args were passed to a C-variadic `fn`.
564 let sig = callee.layout.ty.fn_sig(bx.tcx());
567 // Handle intrinsics old codegen wants Expr's for, ourselves.
568 let intrinsic = match def {
569 Some(ty::InstanceDef::Intrinsic(def_id))
570 | Some(ty::InstanceDef::InjectedCode(def_id)) => {
571 Some(bx.tcx().item_name(def_id).as_str())
575 let intrinsic = intrinsic.as_ref().map(|s| &s[..]);
577 let extra_args = &args[sig.inputs().skip_binder().len()..];
578 let extra_args = extra_args
581 let op_ty = op_arg.ty(self.mir, bx.tcx());
582 self.monomorphize(&op_ty)
584 .collect::<Vec<_>>();
586 let fn_abi = match instance {
587 Some(instance) => FnAbi::of_instance(&bx, instance, &extra_args),
588 None => FnAbi::of_fn_ptr(&bx, sig, &extra_args),
591 if intrinsic == Some("transmute") {
592 if let Some(destination_ref) = destination.as_ref() {
593 let &(dest, target) = destination_ref;
594 self.codegen_transmute(&mut bx, &args[0], dest);
595 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
596 helper.funclet_br(self, &mut bx, target);
598 // If we are trying to transmute to an uninhabited type,
599 // it is likely there is no allotted destination. In fact,
600 // transmuting to an uninhabited type is UB, which means
601 // we can do what we like. Here, we declare that transmuting
602 // into an uninhabited type is impossible, so anything following
603 // it must be unreachable.
604 assert_eq!(fn_abi.ret.layout.abi, abi::Abi::Uninhabited);
610 // For normal codegen, this Miri-specific intrinsic should never occur.
611 if intrinsic == Some("miri_start_panic") {
612 bug!("`miri_start_panic` should never end up in compiled code");
615 if self.codegen_panic_intrinsic(
627 // The arguments we'll be passing. Plus one to account for outptr, if used.
628 let arg_count = fn_abi.args.len() + fn_abi.ret.is_indirect() as usize;
629 let mut llargs = Vec::with_capacity(arg_count);
631 // Prepare the return value destination
632 let ret_dest = if let Some((dest, _)) = *destination {
633 let is_intrinsic = intrinsic.is_some();
634 self.make_return_dest(&mut bx, dest, &fn_abi.ret, &mut llargs, is_intrinsic)
639 if intrinsic == Some("caller_location") {
640 if let Some((_, target)) = destination.as_ref() {
641 let location = self.get_caller_location(&mut bx, fn_span);
643 if let ReturnDest::IndirectOperand(tmp, _) = ret_dest {
644 location.val.store(&mut bx, tmp);
646 self.store_return(&mut bx, ret_dest, &fn_abi.ret, location.immediate());
648 helper.maybe_sideeffect(self.mir, &mut bx, &[*target]);
649 helper.funclet_br(self, &mut bx, *target);
654 if intrinsic.is_some() && intrinsic != Some("drop_in_place") {
655 let dest = match ret_dest {
656 _ if fn_abi.ret.is_indirect() => llargs[0],
657 ReturnDest::Nothing => {
658 bx.const_undef(bx.type_ptr_to(bx.arg_memory_ty(&fn_abi.ret)))
660 ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) => dst.llval,
661 ReturnDest::DirectOperand(_) => {
662 bug!("Cannot use direct operand with an intrinsic call")
666 let args: Vec<_> = args
670 // The indices passed to simd_shuffle* in the
671 // third argument must be constant. This is
672 // checked by const-qualification, which also
673 // promotes any complex rvalues to constants.
674 if i == 2 && intrinsic.unwrap().starts_with("simd_shuffle") {
675 if let mir::Operand::Constant(constant) = arg {
676 let c = self.eval_mir_constant(constant);
677 let (llval, ty) = self.simd_shuffle_indices(
683 return OperandRef { val: Immediate(llval), layout: bx.layout_of(ty) };
685 span_bug!(span, "shuffle indices must be constant");
689 self.codegen_operand(&mut bx, arg)
693 bx.codegen_intrinsic_call(
694 *instance.as_ref().unwrap(),
698 terminator.source_info.span,
702 if let ReturnDest::IndirectOperand(dst, _) = ret_dest {
703 self.store_return(&mut bx, ret_dest, &fn_abi.ret, dst.llval);
706 if let Some((_, target)) = *destination {
707 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
708 helper.funclet_br(self, &mut bx, target);
716 // Split the rust-call tupled arguments off.
717 let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() {
718 let (tup, args) = args.split_last().unwrap();
724 'make_args: for (i, arg) in first_args.iter().enumerate() {
725 let mut op = self.codegen_operand(&mut bx, arg);
727 if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) {
728 if let Pair(..) = op.val {
729 // In the case of Rc<Self>, we need to explicitly pass a
730 // *mut RcBox<Self> with a Scalar (not ScalarPair) ABI. This is a hack
731 // that is understood elsewhere in the compiler as a method on
733 // To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
734 // we get a value of a built-in pointer type
735 'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
736 && !op.layout.ty.is_region_ptr()
738 for i in 0..op.layout.fields.count() {
739 let field = op.extract_field(&mut bx, i);
740 if !field.layout.is_zst() {
741 // we found the one non-zero-sized field that is allowed
742 // now find *its* non-zero-sized field, or stop if it's a
745 continue 'descend_newtypes;
749 span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
752 // now that we have `*dyn Trait` or `&dyn Trait`, split it up into its
753 // data pointer and vtable. Look up the method in the vtable, and pass
754 // the data pointer as the first argument
756 Pair(data_ptr, meta) => {
758 meth::VirtualIndex::from_index(idx).get_fn(&mut bx, meta, &fn_abi),
760 llargs.push(data_ptr);
763 other => bug!("expected a Pair, got {:?}", other),
765 } else if let Ref(data_ptr, Some(meta), _) = op.val {
766 // by-value dynamic dispatch
767 llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(&mut bx, meta, &fn_abi));
768 llargs.push(data_ptr);
771 span_bug!(span, "can't codegen a virtual call on {:?}", op);
775 // The callee needs to own the argument memory if we pass it
776 // by-ref, so make a local copy of non-immediate constants.
777 match (arg, op.val) {
778 (&mir::Operand::Copy(_), Ref(_, None, _))
779 | (&mir::Operand::Constant(_), Ref(_, None, _)) => {
780 let tmp = PlaceRef::alloca(&mut bx, op.layout);
781 op.val.store(&mut bx, tmp);
782 op.val = Ref(tmp.llval, None, tmp.align);
787 self.codegen_argument(&mut bx, op, &mut llargs, &fn_abi.args[i]);
789 if let Some(tup) = untuple {
790 self.codegen_arguments_untupled(
794 &fn_abi.args[first_args.len()..],
799 instance.map_or(false, |i| i.def.requires_caller_location(self.cx.tcx()));
804 "#[track_caller] fn's must have 1 more argument in their ABI than in their MIR",
806 let location = self.get_caller_location(&mut bx, fn_span);
808 "codegen_call_terminator({:?}): location={:?} (fn_span {:?})",
809 terminator, location, fn_span
812 let last_arg = fn_abi.args.last().unwrap();
813 self.codegen_argument(&mut bx, location, &mut llargs, last_arg);
816 let fn_ptr = match (llfn, instance) {
817 (Some(llfn), _) => llfn,
818 (None, Some(instance)) => bx.get_fn_addr(instance),
819 _ => span_bug!(span, "no llfn for call"),
822 if let Some((_, target)) = destination.as_ref() {
823 helper.maybe_sideeffect(self.mir, &mut bx, &[*target]);
831 destination.as_ref().map(|&(_, target)| (ret_dest, target)),
836 fn codegen_asm_terminator(
838 helper: TerminatorCodegenHelper<'tcx>,
840 terminator: &mir::Terminator<'tcx>,
841 template: &[ast::InlineAsmTemplatePiece],
842 operands: &[mir::InlineAsmOperand<'tcx>],
843 options: ast::InlineAsmOptions,
845 destination: Option<mir::BasicBlock>,
847 let span = terminator.source_info.span;
849 let operands: Vec<_> = operands
851 .map(|op| match *op {
852 mir::InlineAsmOperand::In { reg, ref value } => {
853 let value = self.codegen_operand(&mut bx, value);
854 InlineAsmOperandRef::In { reg, value }
856 mir::InlineAsmOperand::Out { reg, late, ref place } => {
857 let place = place.map(|place| self.codegen_place(&mut bx, place.as_ref()));
858 InlineAsmOperandRef::Out { reg, late, place }
860 mir::InlineAsmOperand::InOut { reg, late, ref in_value, ref out_place } => {
861 let in_value = self.codegen_operand(&mut bx, in_value);
863 out_place.map(|out_place| self.codegen_place(&mut bx, out_place.as_ref()));
864 InlineAsmOperandRef::InOut { reg, late, in_value, out_place }
866 mir::InlineAsmOperand::Const { ref value } => {
867 if let mir::Operand::Constant(constant) = value {
868 let const_value = self
869 .eval_mir_constant(constant)
870 .unwrap_or_else(|_| span_bug!(span, "asm const cannot be resolved"));
871 let ty = constant.literal.ty;
872 let size = bx.layout_of(ty).size;
873 let scalar = match const_value {
874 // Promoted constants are evaluated into a ByRef instead of a Scalar,
875 // but we want the scalar value here.
876 ConstValue::ByRef { alloc, offset } => {
877 let ptr = Pointer::new(AllocId(0), offset);
879 .read_scalar(&bx, ptr, size)
880 .and_then(|s| s.not_undef())
881 .unwrap_or_else(|e| {
882 bx.tcx().sess.span_err(
884 &format!("Could not evaluate asm const: {}", e),
887 // We are erroring out, just emit a dummy constant.
891 _ => span_bug!(span, "expected ByRef for promoted asm const"),
893 let value = scalar.assert_bits(size);
894 let string = match ty.kind {
895 ty::Uint(_) => value.to_string(),
897 match int_ty.normalize(bx.tcx().sess.target.ptr_width) {
898 ast::IntTy::I8 => (value as i8).to_string(),
899 ast::IntTy::I16 => (value as i16).to_string(),
900 ast::IntTy::I32 => (value as i32).to_string(),
901 ast::IntTy::I64 => (value as i64).to_string(),
902 ast::IntTy::I128 => (value as i128).to_string(),
903 ast::IntTy::Isize => unreachable!(),
906 ty::Float(ast::FloatTy::F32) => {
907 f32::from_bits(value as u32).to_string()
909 ty::Float(ast::FloatTy::F64) => {
910 f64::from_bits(value as u64).to_string()
912 _ => span_bug!(span, "asm const has bad type {}", ty),
914 InlineAsmOperandRef::Const { string }
916 span_bug!(span, "asm const is not a constant");
919 mir::InlineAsmOperand::SymFn { ref value } => {
920 let literal = self.monomorphize(&value.literal);
921 if let ty::FnDef(def_id, substs) = literal.ty.kind {
922 let instance = ty::Instance::resolve_for_fn_ptr(
924 ty::ParamEnv::reveal_all(),
929 InlineAsmOperandRef::SymFn { instance }
931 span_bug!(span, "invalid type for asm sym (fn)");
934 mir::InlineAsmOperand::SymStatic { def_id } => {
935 InlineAsmOperandRef::SymStatic { def_id }
940 bx.codegen_inline_asm(template, &operands, options, line_spans);
942 if let Some(target) = destination {
943 helper.funclet_br(self, &mut bx, target);
950 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
951 pub fn codegen_block(&mut self, bb: mir::BasicBlock) {
952 let mut bx = self.build_block(bb);
956 debug!("codegen_block({:?}={:?})", bb, data);
958 for statement in &data.statements {
959 bx = self.codegen_statement(bx, statement);
962 self.codegen_terminator(bx, bb, data.terminator());
965 fn codegen_terminator(
969 terminator: &'tcx mir::Terminator<'tcx>,
971 debug!("codegen_terminator: {:?}", terminator);
973 // Create the cleanup bundle, if needed.
974 let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
975 let helper = TerminatorCodegenHelper { bb, terminator, funclet_bb };
977 self.set_debug_loc(&mut bx, terminator.source_info);
978 match terminator.kind {
979 mir::TerminatorKind::Resume => self.codegen_resume_terminator(helper, bx),
981 mir::TerminatorKind::Abort => {
983 // `abort` does not terminate the block, so we still need to generate
984 // an `unreachable` terminator after it.
988 mir::TerminatorKind::Goto { target } => {
989 helper.maybe_sideeffect(self.mir, &mut bx, &[target]);
990 helper.funclet_br(self, &mut bx, target);
993 mir::TerminatorKind::SwitchInt { ref discr, switch_ty, ref values, ref targets } => {
994 self.codegen_switchint_terminator(helper, bx, discr, switch_ty, values, targets);
997 mir::TerminatorKind::Return => {
998 self.codegen_return_terminator(bx);
1001 mir::TerminatorKind::Unreachable => {
1005 mir::TerminatorKind::Drop { location, target, unwind } => {
1006 self.codegen_drop_terminator(helper, bx, location, target, unwind);
1009 mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
1010 self.codegen_assert_terminator(
1011 helper, bx, terminator, cond, expected, msg, target, cleanup,
1015 mir::TerminatorKind::DropAndReplace { .. } => {
1016 bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
1019 mir::TerminatorKind::Call {
1027 self.codegen_call_terminator(
1038 mir::TerminatorKind::GeneratorDrop | mir::TerminatorKind::Yield { .. } => {
1039 bug!("generator ops in codegen")
1041 mir::TerminatorKind::FalseEdge { .. } | mir::TerminatorKind::FalseUnwind { .. } => {
1042 bug!("borrowck false edges in codegen")
1045 mir::TerminatorKind::InlineAsm {
1052 self.codegen_asm_terminator(
1066 fn codegen_argument(
1069 op: OperandRef<'tcx, Bx::Value>,
1070 llargs: &mut Vec<Bx::Value>,
1071 arg: &ArgAbi<'tcx, Ty<'tcx>>,
1073 // Fill padding with undef value, where applicable.
1074 if let Some(ty) = arg.pad {
1075 llargs.push(bx.const_undef(bx.reg_backend_type(&ty)))
1078 if arg.is_ignore() {
1082 if let PassMode::Pair(..) = arg.mode {
1089 _ => bug!("codegen_argument: {:?} invalid for pair argument", op),
1091 } else if arg.is_unsized_indirect() {
1093 Ref(a, Some(b), _) => {
1098 _ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op),
1102 // Force by-ref if we have to load through a cast pointer.
1103 let (mut llval, align, by_ref) = match op.val {
1104 Immediate(_) | Pair(..) => match arg.mode {
1105 PassMode::Indirect(..) | PassMode::Cast(_) => {
1106 let scratch = PlaceRef::alloca(bx, arg.layout);
1107 op.val.store(bx, scratch);
1108 (scratch.llval, scratch.align, true)
1110 _ => (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false),
1112 Ref(llval, _, align) => {
1113 if arg.is_indirect() && align < arg.layout.align.abi {
1114 // `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I
1115 // think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't
1116 // have scary latent bugs around.
1118 let scratch = PlaceRef::alloca(bx, arg.layout);
1128 (scratch.llval, scratch.align, true)
1130 (llval, align, true)
1135 if by_ref && !arg.is_indirect() {
1136 // Have to load the argument, maybe while casting it.
1137 if let PassMode::Cast(ty) = arg.mode {
1138 let addr = bx.pointercast(llval, bx.type_ptr_to(bx.cast_backend_type(&ty)));
1139 llval = bx.load(addr, align.min(arg.layout.align.abi));
1141 // We can't use `PlaceRef::load` here because the argument
1142 // may have a type we don't treat as immediate, but the ABI
1143 // used for this call is passing it by-value. In that case,
1144 // the load would just produce `OperandValue::Ref` instead
1145 // of the `OperandValue::Immediate` we need for the call.
1146 llval = bx.load(llval, align);
1147 if let abi::Abi::Scalar(ref scalar) = arg.layout.abi {
1148 if scalar.is_bool() {
1149 bx.range_metadata(llval, 0..2);
1152 // We store bools as `i8` so we need to truncate to `i1`.
1153 llval = base::to_immediate(bx, llval, arg.layout);
1160 fn codegen_arguments_untupled(
1163 operand: &mir::Operand<'tcx>,
1164 llargs: &mut Vec<Bx::Value>,
1165 args: &[ArgAbi<'tcx, Ty<'tcx>>],
1167 let tuple = self.codegen_operand(bx, operand);
1169 // Handle both by-ref and immediate tuples.
1170 if let Ref(llval, None, align) = tuple.val {
1171 let tuple_ptr = PlaceRef::new_sized_aligned(llval, tuple.layout, align);
1172 for i in 0..tuple.layout.fields.count() {
1173 let field_ptr = tuple_ptr.project_field(bx, i);
1174 let field = bx.load_operand(field_ptr);
1175 self.codegen_argument(bx, field, llargs, &args[i]);
1177 } else if let Ref(_, Some(_), _) = tuple.val {
1178 bug!("closure arguments must be sized")
1180 // If the tuple is immediate, the elements are as well.
1181 for i in 0..tuple.layout.fields.count() {
1182 let op = tuple.extract_field(bx, i);
1183 self.codegen_argument(bx, op, llargs, &args[i]);
1188 fn get_caller_location(&mut self, bx: &mut Bx, span: Span) -> OperandRef<'tcx, Bx::Value> {
1189 self.caller_location.unwrap_or_else(|| {
1190 let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
1191 let caller = bx.tcx().sess.source_map().lookup_char_pos(topmost.lo());
1192 let const_loc = bx.tcx().const_caller_location((
1193 Symbol::intern(&caller.file.name.to_string()),
1195 caller.col_display as u32 + 1,
1197 OperandRef::from_const(bx, const_loc, bx.tcx().caller_location_ty())
1201 fn get_personality_slot(&mut self, bx: &mut Bx) -> PlaceRef<'tcx, Bx::Value> {
1203 if let Some(slot) = self.personality_slot {
1206 let layout = cx.layout_of(
1207 cx.tcx().intern_tup(&[cx.tcx().mk_mut_ptr(cx.tcx().types.u8), cx.tcx().types.i32]),
1209 let slot = PlaceRef::alloca(bx, layout);
1210 self.personality_slot = Some(slot);
1215 /// Returns the landing-pad wrapper around the given basic block.
1217 /// No-op in MSVC SEH scheme.
1218 fn landing_pad_to(&mut self, target_bb: mir::BasicBlock) -> Bx::BasicBlock {
1219 if let Some(block) = self.landing_pads[target_bb] {
1223 let block = self.blocks[target_bb];
1224 let landing_pad = self.landing_pad_uncached(block);
1225 self.landing_pads[target_bb] = Some(landing_pad);
1229 fn landing_pad_uncached(&mut self, target_bb: Bx::BasicBlock) -> Bx::BasicBlock {
1230 if base::wants_msvc_seh(self.cx.sess()) {
1231 span_bug!(self.mir.span, "landing pad was not inserted?")
1234 let mut bx = self.new_block("cleanup");
1236 let llpersonality = self.cx.eh_personality();
1237 let llretty = self.landing_pad_type();
1238 let lp = bx.landing_pad(llretty, llpersonality, 1);
1241 let slot = self.get_personality_slot(&mut bx);
1242 slot.storage_live(&mut bx);
1243 Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot);
1249 fn landing_pad_type(&self) -> Bx::Type {
1251 cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
1254 fn unreachable_block(&mut self) -> Bx::BasicBlock {
1255 self.unreachable_block.unwrap_or_else(|| {
1256 let mut bx = self.new_block("unreachable");
1258 self.unreachable_block = Some(bx.llbb());
1263 pub fn new_block(&self, name: &str) -> Bx {
1264 Bx::new_block(self.cx, self.llfn, name)
1267 pub fn build_block(&self, bb: mir::BasicBlock) -> Bx {
1268 let mut bx = Bx::with_cx(self.cx);
1269 bx.position_at_end(self.blocks[bb]);
1273 fn make_return_dest(
1276 dest: mir::Place<'tcx>,
1277 fn_ret: &ArgAbi<'tcx, Ty<'tcx>>,
1278 llargs: &mut Vec<Bx::Value>,
1280 ) -> ReturnDest<'tcx, Bx::Value> {
1281 // If the return is ignored, we can just return a do-nothing `ReturnDest`.
1282 if fn_ret.is_ignore() {
1283 return ReturnDest::Nothing;
1285 let dest = if let Some(index) = dest.as_local() {
1286 match self.locals[index] {
1287 LocalRef::Place(dest) => dest,
1288 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
1289 LocalRef::Operand(None) => {
1290 // Handle temporary places, specifically `Operand` ones, as
1291 // they don't have `alloca`s.
1292 return if fn_ret.is_indirect() {
1293 // Odd, but possible, case, we have an operand temporary,
1294 // but the calling convention has an indirect return.
1295 let tmp = PlaceRef::alloca(bx, fn_ret.layout);
1296 tmp.storage_live(bx);
1297 llargs.push(tmp.llval);
1298 ReturnDest::IndirectOperand(tmp, index)
1299 } else if is_intrinsic {
1300 // Currently, intrinsics always need a location to store
1301 // the result, so we create a temporary `alloca` for the
1303 let tmp = PlaceRef::alloca(bx, fn_ret.layout);
1304 tmp.storage_live(bx);
1305 ReturnDest::IndirectOperand(tmp, index)
1307 ReturnDest::DirectOperand(index)
1310 LocalRef::Operand(Some(_)) => {
1311 bug!("place local already assigned to");
1317 mir::PlaceRef { local: dest.local, projection: &dest.projection },
1320 if fn_ret.is_indirect() {
1321 if dest.align < dest.layout.align.abi {
1322 // Currently, MIR code generation does not create calls
1323 // that store directly to fields of packed structs (in
1324 // fact, the calls it creates write only to temps).
1326 // If someone changes that, please update this code path
1327 // to create a temporary.
1328 span_bug!(self.mir.span, "can't directly store to unaligned value");
1330 llargs.push(dest.llval);
1333 ReturnDest::Store(dest)
1337 fn codegen_transmute(&mut self, bx: &mut Bx, src: &mir::Operand<'tcx>, dst: mir::Place<'tcx>) {
1338 if let Some(index) = dst.as_local() {
1339 match self.locals[index] {
1340 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
1341 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
1342 LocalRef::Operand(None) => {
1343 let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst.as_ref()));
1344 assert!(!dst_layout.ty.has_erasable_regions());
1345 let place = PlaceRef::alloca(bx, dst_layout);
1346 place.storage_live(bx);
1347 self.codegen_transmute_into(bx, src, place);
1348 let op = bx.load_operand(place);
1349 place.storage_dead(bx);
1350 self.locals[index] = LocalRef::Operand(Some(op));
1351 self.debug_introduce_local(bx, index);
1353 LocalRef::Operand(Some(op)) => {
1354 assert!(op.layout.is_zst(), "assigning to initialized SSAtemp");
1358 let dst = self.codegen_place(bx, dst.as_ref());
1359 self.codegen_transmute_into(bx, src, dst);
1363 fn codegen_transmute_into(
1366 src: &mir::Operand<'tcx>,
1367 dst: PlaceRef<'tcx, Bx::Value>,
1369 let src = self.codegen_operand(bx, src);
1370 let llty = bx.backend_type(src.layout);
1371 let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty));
1372 let align = src.layout.align.abi.min(dst.align);
1373 src.val.store(bx, PlaceRef::new_sized_aligned(cast_ptr, src.layout, align));
1376 // Stores the return value of a function call into it's final location.
1380 dest: ReturnDest<'tcx, Bx::Value>,
1381 ret_abi: &ArgAbi<'tcx, Ty<'tcx>>,
1384 use self::ReturnDest::*;
1388 Store(dst) => bx.store_arg(&ret_abi, llval, dst),
1389 IndirectOperand(tmp, index) => {
1390 let op = bx.load_operand(tmp);
1391 tmp.storage_dead(bx);
1392 self.locals[index] = LocalRef::Operand(Some(op));
1393 self.debug_introduce_local(bx, index);
1395 DirectOperand(index) => {
1396 // If there is a cast, we have to store and reload.
1397 let op = if let PassMode::Cast(_) = ret_abi.mode {
1398 let tmp = PlaceRef::alloca(bx, ret_abi.layout);
1399 tmp.storage_live(bx);
1400 bx.store_arg(&ret_abi, llval, tmp);
1401 let op = bx.load_operand(tmp);
1402 tmp.storage_dead(bx);
1405 OperandRef::from_immediate_or_packed_pair(bx, llval, ret_abi.layout)
1407 self.locals[index] = LocalRef::Operand(Some(op));
1408 self.debug_introduce_local(bx, index);
1414 enum ReturnDest<'tcx, V> {
1415 // Do nothing; the return value is indirect or ignored.
1417 // Store the return value to the pointer.
1418 Store(PlaceRef<'tcx, V>),
1419 // Store an indirect return value to an operand local place.
1420 IndirectOperand(PlaceRef<'tcx, V>, mir::Local),
1421 // Store a direct return value to an operand local place.
1422 DirectOperand(mir::Local),