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::LangItem;
14 use rustc_index::vec::Idx;
15 use rustc_middle::mir::AssertKind;
16 use rustc_middle::mir::{self, SwitchTargets};
17 use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
18 use rustc_middle::ty::print::with_no_trimmed_paths;
19 use rustc_middle::ty::{self, Instance, Ty, TypeFoldable};
20 use rustc_span::source_map::Span;
21 use rustc_span::{sym, Symbol};
22 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode};
23 use rustc_target::abi::{self, LayoutOf};
24 use rustc_target::spec::abi::Abi;
26 /// Used by `FunctionCx::codegen_terminator` for emitting common patterns
27 /// e.g., creating a basic block, calling a function, etc.
28 struct TerminatorCodegenHelper<'tcx> {
30 terminator: &'tcx mir::Terminator<'tcx>,
31 funclet_bb: Option<mir::BasicBlock>,
34 impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
35 /// Returns the associated funclet from `FunctionCx::funclets` for the
36 /// `funclet_bb` member if it is not `None`.
37 fn funclet<'b, Bx: BuilderMethods<'a, 'tcx>>(
39 fx: &'b FunctionCx<'a, 'tcx, Bx>,
40 ) -> Option<&'b Bx::Funclet> {
41 self.funclet_bb.and_then(|funcl| fx.funclets[funcl].as_ref())
44 fn lltarget<Bx: BuilderMethods<'a, 'tcx>>(
46 fx: &mut FunctionCx<'a, 'tcx, Bx>,
47 target: mir::BasicBlock,
48 ) -> (Bx::BasicBlock, bool) {
49 let span = self.terminator.source_info.span;
50 let lltarget = fx.blocks[target];
51 let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
52 match (self.funclet_bb, target_funclet) {
53 (None, None) => (lltarget, false),
54 (Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) => {
57 // jump *into* cleanup - need a landing pad if GNU
58 (None, Some(_)) => (fx.landing_pad_to(target), false),
59 (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
60 (Some(_), Some(_)) => (fx.landing_pad_to(target), true),
64 /// Create a basic block.
65 fn llblock<Bx: BuilderMethods<'a, 'tcx>>(
67 fx: &mut FunctionCx<'a, 'tcx, Bx>,
68 target: mir::BasicBlock,
70 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
72 // MSVC cross-funclet jump - need a trampoline
74 debug!("llblock: creating cleanup trampoline for {:?}", target);
75 let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
76 let mut trampoline = fx.new_block(name);
77 trampoline.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
84 fn funclet_br<Bx: BuilderMethods<'a, 'tcx>>(
86 fx: &mut FunctionCx<'a, 'tcx, Bx>,
88 target: mir::BasicBlock,
90 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
92 // micro-optimization: generate a `ret` rather than a jump
94 bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
100 /// Call `fn_ptr` of `fn_abi` with the arguments `llargs`, the optional
101 /// return destination `destination` and the cleanup function `cleanup`.
102 fn do_call<Bx: BuilderMethods<'a, 'tcx>>(
104 fx: &mut FunctionCx<'a, 'tcx, Bx>,
106 fn_abi: FnAbi<'tcx, Ty<'tcx>>,
108 llargs: &[Bx::Value],
109 destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>,
110 cleanup: Option<mir::BasicBlock>,
112 // If there is a cleanup block and the function we're calling can unwind, then
113 // do an invoke, otherwise do a call.
114 if let Some(cleanup) = cleanup.filter(|_| fn_abi.can_unwind) {
115 let ret_bx = if let Some((_, target)) = destination {
118 fx.unreachable_block()
121 bx.invoke(fn_ptr, &llargs, ret_bx, self.llblock(fx, cleanup), self.funclet(fx));
122 bx.apply_attrs_callsite(&fn_abi, invokeret);
124 if let Some((ret_dest, target)) = destination {
125 let mut ret_bx = fx.build_block(target);
126 fx.set_debug_loc(&mut ret_bx, self.terminator.source_info);
127 fx.store_return(&mut ret_bx, ret_dest, &fn_abi.ret, invokeret);
130 let llret = bx.call(fn_ptr, &llargs, self.funclet(fx));
131 bx.apply_attrs_callsite(&fn_abi, llret);
132 if fx.mir[self.bb].is_cleanup {
133 // Cleanup is always the cold path. Don't inline
134 // drop glue. Also, when there is a deeply-nested
135 // struct, there are "symmetry" issues that cause
136 // exponential inlining - see issue #41696.
137 bx.do_not_inline(llret);
140 if let Some((ret_dest, target)) = destination {
141 fx.store_return(bx, ret_dest, &fn_abi.ret, llret);
142 self.funclet_br(fx, bx, target);
150 /// Codegen implementations for some terminator variants.
151 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
152 /// Generates code for a `Resume` terminator.
153 fn codegen_resume_terminator(&mut self, helper: TerminatorCodegenHelper<'tcx>, mut bx: Bx) {
154 if let Some(funclet) = helper.funclet(self) {
155 bx.cleanup_ret(funclet, None);
157 let slot = self.get_personality_slot(&mut bx);
158 let lp0 = slot.project_field(&mut bx, 0);
159 let lp0 = bx.load_operand(lp0).immediate();
160 let lp1 = slot.project_field(&mut bx, 1);
161 let lp1 = bx.load_operand(lp1).immediate();
162 slot.storage_dead(&mut bx);
164 let mut lp = bx.const_undef(self.landing_pad_type());
165 lp = bx.insert_value(lp, lp0, 0);
166 lp = bx.insert_value(lp, lp1, 1);
171 fn codegen_switchint_terminator(
173 helper: TerminatorCodegenHelper<'tcx>,
175 discr: &mir::Operand<'tcx>,
177 targets: &SwitchTargets,
179 let discr = self.codegen_operand(&mut bx, &discr);
180 // `switch_ty` is redundant, sanity-check that.
181 assert_eq!(discr.layout.ty, switch_ty);
182 let mut target_iter = targets.iter();
183 if target_iter.len() == 1 {
184 // If there are two targets (one conditional, one fallback), emit br instead of switch
185 let (test_value, target) = target_iter.next().unwrap();
186 let lltrue = helper.llblock(self, target);
187 let llfalse = helper.llblock(self, targets.otherwise());
188 if switch_ty == bx.tcx().types.bool {
189 // Don't generate trivial icmps when switching on bool
191 0 => bx.cond_br(discr.immediate(), llfalse, lltrue),
192 1 => bx.cond_br(discr.immediate(), lltrue, llfalse),
196 let switch_llty = bx.immediate_backend_type(bx.layout_of(switch_ty));
197 let llval = bx.const_uint_big(switch_llty, test_value);
198 let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval);
199 bx.cond_br(cmp, lltrue, llfalse);
204 helper.llblock(self, targets.otherwise()),
205 target_iter.map(|(value, target)| (value, helper.llblock(self, target))),
210 fn codegen_return_terminator(&mut self, mut bx: Bx) {
211 // Call `va_end` if this is the definition of a C-variadic function.
212 if self.fn_abi.c_variadic {
213 // The `VaList` "spoofed" argument is just after all the real arguments.
214 let va_list_arg_idx = self.fn_abi.args.len();
215 match self.locals[mir::Local::new(1 + va_list_arg_idx)] {
216 LocalRef::Place(va_list) => {
217 bx.va_end(va_list.llval);
219 _ => bug!("C-variadic function must have a `VaList` place"),
222 if self.fn_abi.ret.layout.abi.is_uninhabited() {
223 // Functions with uninhabited return values are marked `noreturn`,
224 // so we should make sure that we never actually do.
225 // We play it safe by using a well-defined `abort`, but we could go for immediate UB
226 // if that turns out to be helpful.
228 // `abort` does not terminate the block, so we still need to generate
229 // an `unreachable` terminator after it.
233 let llval = match self.fn_abi.ret.mode {
234 PassMode::Ignore | PassMode::Indirect { .. } => {
239 PassMode::Direct(_) | PassMode::Pair(..) => {
240 let op = self.codegen_consume(&mut bx, mir::Place::return_place().as_ref());
241 if let Ref(llval, _, align) = op.val {
242 bx.load(llval, align)
244 op.immediate_or_packed_pair(&mut bx)
248 PassMode::Cast(cast_ty) => {
249 let op = match self.locals[mir::RETURN_PLACE] {
250 LocalRef::Operand(Some(op)) => op,
251 LocalRef::Operand(None) => bug!("use of return before def"),
252 LocalRef::Place(cg_place) => OperandRef {
253 val: Ref(cg_place.llval, None, cg_place.align),
254 layout: cg_place.layout,
256 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
258 let llslot = match op.val {
259 Immediate(_) | Pair(..) => {
260 let scratch = PlaceRef::alloca(&mut bx, self.fn_abi.ret.layout);
261 op.val.store(&mut bx, scratch);
264 Ref(llval, _, align) => {
265 assert_eq!(align, op.layout.align.abi, "return place is unaligned!");
269 let addr = bx.pointercast(llslot, bx.type_ptr_to(bx.cast_backend_type(&cast_ty)));
270 bx.load(addr, self.fn_abi.ret.layout.align.abi)
276 fn codegen_drop_terminator(
278 helper: TerminatorCodegenHelper<'tcx>,
280 location: mir::Place<'tcx>,
281 target: mir::BasicBlock,
282 unwind: Option<mir::BasicBlock>,
284 let ty = location.ty(self.mir, bx.tcx()).ty;
285 let ty = self.monomorphize(ty);
286 let drop_fn = Instance::resolve_drop_in_place(bx.tcx(), ty);
288 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
289 // we don't actually need to drop anything.
290 helper.funclet_br(self, &mut bx, target);
294 let place = self.codegen_place(&mut bx, location.as_ref());
296 let mut args = if let Some(llextra) = place.llextra {
297 args2 = [place.llval, llextra];
300 args1 = [place.llval];
303 let (drop_fn, fn_abi) = match ty.kind() {
304 // FIXME(eddyb) perhaps move some of this logic into
305 // `Instance::resolve_drop_in_place`?
307 let virtual_drop = Instance {
308 def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
309 substs: drop_fn.substs,
311 let fn_abi = FnAbi::of_instance(&bx, virtual_drop, &[]);
312 let vtable = args[1];
314 (meth::DESTRUCTOR.get_fn(&mut bx, vtable, &fn_abi), fn_abi)
316 _ => (bx.get_fn_addr(drop_fn), FnAbi::of_instance(&bx, drop_fn, &[])),
324 Some((ReturnDest::Nothing, target)),
329 fn codegen_assert_terminator(
331 helper: TerminatorCodegenHelper<'tcx>,
333 terminator: &mir::Terminator<'tcx>,
334 cond: &mir::Operand<'tcx>,
336 msg: &mir::AssertMessage<'tcx>,
337 target: mir::BasicBlock,
338 cleanup: Option<mir::BasicBlock>,
340 let span = terminator.source_info.span;
341 let cond = self.codegen_operand(&mut bx, cond).immediate();
342 let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
344 // This case can currently arise only from functions marked
345 // with #[rustc_inherit_overflow_checks] and inlined from
346 // another crate (mostly core::num generic/#[inline] fns),
347 // while the current crate doesn't use overflow checks.
348 // NOTE: Unlike binops, negation doesn't have its own
349 // checked operation, just a comparison with the minimum
350 // value, so we have to check for the assert message.
351 if !bx.check_overflow() {
352 if let AssertKind::OverflowNeg(_) = *msg {
353 const_cond = Some(expected);
357 // Don't codegen the panic block if success if known.
358 if const_cond == Some(expected) {
359 helper.funclet_br(self, &mut bx, target);
363 // Pass the condition through llvm.expect for branch hinting.
364 let cond = bx.expect(cond, expected);
366 // Create the failure block and the conditional branch to it.
367 let lltarget = helper.llblock(self, target);
368 let panic_block = self.new_block("panic");
370 bx.cond_br(cond, lltarget, panic_block.llbb());
372 bx.cond_br(cond, panic_block.llbb(), lltarget);
375 // After this point, bx is the block for the call to panic.
377 self.set_debug_loc(&mut bx, terminator.source_info);
379 // Get the location information.
380 let location = self.get_caller_location(&mut bx, terminator.source_info).immediate();
382 // Put together the arguments to the panic entry point.
383 let (lang_item, args) = match msg {
384 AssertKind::BoundsCheck { ref len, ref index } => {
385 let len = self.codegen_operand(&mut bx, len).immediate();
386 let index = self.codegen_operand(&mut bx, index).immediate();
387 // It's `fn panic_bounds_check(index: usize, len: usize)`,
388 // and `#[track_caller]` adds an implicit third argument.
389 (LangItem::PanicBoundsCheck, vec![index, len, location])
392 let msg_str = Symbol::intern(msg.description());
393 let msg = bx.const_str(msg_str);
394 // It's `pub fn panic(expr: &str)`, with the wide reference being passed
395 // as two arguments, and `#[track_caller]` adds an implicit third argument.
396 (LangItem::Panic, vec![msg.0, msg.1, location])
400 // Obtain the panic entry point.
401 let def_id = common::langcall(bx.tcx(), Some(span), "", lang_item);
402 let instance = ty::Instance::mono(bx.tcx(), def_id);
403 let fn_abi = FnAbi::of_instance(&bx, instance, &[]);
404 let llfn = bx.get_fn_addr(instance);
406 // Codegen the actual panic invoke/call.
407 helper.do_call(self, &mut bx, fn_abi, llfn, &args, None, cleanup);
410 /// Returns `true` if this is indeed a panic intrinsic and codegen is done.
411 fn codegen_panic_intrinsic(
413 helper: &TerminatorCodegenHelper<'tcx>,
415 intrinsic: Option<Symbol>,
416 instance: Option<Instance<'tcx>>,
417 source_info: mir::SourceInfo,
418 destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
419 cleanup: Option<mir::BasicBlock>,
421 // Emit a panic or a no-op for `assert_*` intrinsics.
422 // These are intrinsics that compile to panics so that we can get a message
423 // which mentions the offending type, even from a const context.
424 #[derive(Debug, PartialEq)]
425 enum AssertIntrinsic {
430 let panic_intrinsic = intrinsic.and_then(|i| match i {
431 sym::assert_inhabited => Some(AssertIntrinsic::Inhabited),
432 sym::assert_zero_valid => Some(AssertIntrinsic::ZeroValid),
433 sym::assert_uninit_valid => Some(AssertIntrinsic::UninitValid),
436 if let Some(intrinsic) = panic_intrinsic {
437 use AssertIntrinsic::*;
438 let ty = instance.unwrap().substs.type_at(0);
439 let layout = bx.layout_of(ty);
440 let do_panic = match intrinsic {
441 Inhabited => layout.abi.is_uninhabited(),
442 // We unwrap as the error type is `!`.
443 ZeroValid => !layout.might_permit_raw_init(bx, /*zero:*/ true).unwrap(),
444 // We unwrap as the error type is `!`.
445 UninitValid => !layout.might_permit_raw_init(bx, /*zero:*/ false).unwrap(),
448 let msg_str = with_no_trimmed_paths(|| {
449 if layout.abi.is_uninhabited() {
450 // Use this error even for the other intrinsics as it is more precise.
451 format!("attempted to instantiate uninhabited type `{}`", ty)
452 } else if intrinsic == ZeroValid {
453 format!("attempted to zero-initialize type `{}`, which is invalid", ty)
455 format!("attempted to leave type `{}` uninitialized, which is invalid", ty)
458 let msg = bx.const_str(Symbol::intern(&msg_str));
459 let location = self.get_caller_location(bx, source_info).immediate();
461 // Obtain the panic entry point.
462 // FIXME: dedup this with `codegen_assert_terminator` above.
464 common::langcall(bx.tcx(), Some(source_info.span), "", LangItem::Panic);
465 let instance = ty::Instance::mono(bx.tcx(), def_id);
466 let fn_abi = FnAbi::of_instance(bx, instance, &[]);
467 let llfn = bx.get_fn_addr(instance);
469 // Codegen the actual panic invoke/call.
475 &[msg.0, msg.1, location],
476 destination.as_ref().map(|(_, bb)| (ReturnDest::Nothing, *bb)),
481 let target = destination.as_ref().unwrap().1;
482 helper.funclet_br(self, bx, target)
490 fn codegen_call_terminator(
492 helper: TerminatorCodegenHelper<'tcx>,
494 terminator: &mir::Terminator<'tcx>,
495 func: &mir::Operand<'tcx>,
496 args: &[mir::Operand<'tcx>],
497 destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
498 cleanup: Option<mir::BasicBlock>,
501 let source_info = terminator.source_info;
502 let span = source_info.span;
504 // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
505 let callee = self.codegen_operand(&mut bx, func);
507 let (instance, mut llfn) = match *callee.layout.ty.kind() {
508 ty::FnDef(def_id, substs) => (
510 ty::Instance::resolve(bx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs)
513 .polymorphize(bx.tcx()),
517 ty::FnPtr(_) => (None, Some(callee.immediate())),
518 _ => bug!("{} is not callable", callee.layout.ty),
520 let def = instance.map(|i| i.def);
522 if let Some(ty::InstanceDef::DropGlue(_, None)) = def {
523 // Empty drop glue; a no-op.
524 let &(_, target) = destination.as_ref().unwrap();
525 helper.funclet_br(self, &mut bx, target);
529 // FIXME(eddyb) avoid computing this if possible, when `instance` is
530 // available - right now `sig` is only needed for getting the `abi`
531 // and figuring out how many extra args were passed to a C-variadic `fn`.
532 let sig = callee.layout.ty.fn_sig(bx.tcx());
535 // Handle intrinsics old codegen wants Expr's for, ourselves.
536 let intrinsic = match def {
537 Some(ty::InstanceDef::Intrinsic(def_id)) => Some(bx.tcx().item_name(def_id)),
541 let extra_args = &args[sig.inputs().skip_binder().len()..];
542 let extra_args = extra_args
545 let op_ty = op_arg.ty(self.mir, bx.tcx());
546 self.monomorphize(op_ty)
548 .collect::<Vec<_>>();
550 let fn_abi = match instance {
551 Some(instance) => FnAbi::of_instance(&bx, instance, &extra_args),
552 None => FnAbi::of_fn_ptr(&bx, sig, &extra_args),
555 if intrinsic == Some(sym::transmute) {
556 if let Some(destination_ref) = destination.as_ref() {
557 let &(dest, target) = destination_ref;
558 self.codegen_transmute(&mut bx, &args[0], dest);
559 helper.funclet_br(self, &mut bx, target);
561 // If we are trying to transmute to an uninhabited type,
562 // it is likely there is no allotted destination. In fact,
563 // transmuting to an uninhabited type is UB, which means
564 // we can do what we like. Here, we declare that transmuting
565 // into an uninhabited type is impossible, so anything following
566 // it must be unreachable.
567 assert_eq!(fn_abi.ret.layout.abi, abi::Abi::Uninhabited);
573 if self.codegen_panic_intrinsic(
585 // The arguments we'll be passing. Plus one to account for outptr, if used.
586 let arg_count = fn_abi.args.len() + fn_abi.ret.is_indirect() as usize;
587 let mut llargs = Vec::with_capacity(arg_count);
589 // Prepare the return value destination
590 let ret_dest = if let Some((dest, _)) = *destination {
591 let is_intrinsic = intrinsic.is_some();
592 self.make_return_dest(&mut bx, dest, &fn_abi.ret, &mut llargs, is_intrinsic)
597 if intrinsic == Some(sym::caller_location) {
598 if let Some((_, target)) = destination.as_ref() {
600 .get_caller_location(&mut bx, mir::SourceInfo { span: fn_span, ..source_info });
602 if let ReturnDest::IndirectOperand(tmp, _) = ret_dest {
603 location.val.store(&mut bx, tmp);
605 self.store_return(&mut bx, ret_dest, &fn_abi.ret, location.immediate());
606 helper.funclet_br(self, &mut bx, *target);
612 None | Some(sym::drop_in_place) => {}
613 Some(sym::copy_nonoverlapping) => unreachable!(),
615 let dest = match ret_dest {
616 _ if fn_abi.ret.is_indirect() => llargs[0],
617 ReturnDest::Nothing => {
618 bx.const_undef(bx.type_ptr_to(bx.arg_memory_ty(&fn_abi.ret)))
620 ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) => dst.llval,
621 ReturnDest::DirectOperand(_) => {
622 bug!("Cannot use direct operand with an intrinsic call")
626 let args: Vec<_> = args
630 // The indices passed to simd_shuffle* in the
631 // third argument must be constant. This is
632 // checked by const-qualification, which also
633 // promotes any complex rvalues to constants.
634 if i == 2 && intrinsic.as_str().starts_with("simd_shuffle") {
635 if let mir::Operand::Constant(constant) = arg {
636 let c = self.eval_mir_constant(constant);
638 self.simd_shuffle_indices(&bx, constant.span, constant.ty(), c);
640 val: Immediate(llval),
641 layout: bx.layout_of(ty),
644 span_bug!(span, "shuffle indices must be constant");
648 self.codegen_operand(&mut bx, arg)
652 Self::codegen_intrinsic_call(
654 *instance.as_ref().unwrap(),
661 if let ReturnDest::IndirectOperand(dst, _) = ret_dest {
662 self.store_return(&mut bx, ret_dest, &fn_abi.ret, dst.llval);
665 if let Some((_, target)) = *destination {
666 helper.funclet_br(self, &mut bx, target);
675 // Split the rust-call tupled arguments off.
676 let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() {
677 let (tup, args) = args.split_last().unwrap();
683 'make_args: for (i, arg) in first_args.iter().enumerate() {
684 let mut op = self.codegen_operand(&mut bx, arg);
686 if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) {
687 if let Pair(..) = op.val {
688 // In the case of Rc<Self>, we need to explicitly pass a
689 // *mut RcBox<Self> with a Scalar (not ScalarPair) ABI. This is a hack
690 // that is understood elsewhere in the compiler as a method on
692 // To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
693 // we get a value of a built-in pointer type
694 'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
695 && !op.layout.ty.is_region_ptr()
697 for i in 0..op.layout.fields.count() {
698 let field = op.extract_field(&mut bx, i);
699 if !field.layout.is_zst() {
700 // we found the one non-zero-sized field that is allowed
701 // now find *its* non-zero-sized field, or stop if it's a
704 continue 'descend_newtypes;
708 span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
711 // now that we have `*dyn Trait` or `&dyn Trait`, split it up into its
712 // data pointer and vtable. Look up the method in the vtable, and pass
713 // the data pointer as the first argument
715 Pair(data_ptr, meta) => {
717 meth::VirtualIndex::from_index(idx).get_fn(&mut bx, meta, &fn_abi),
719 llargs.push(data_ptr);
722 other => bug!("expected a Pair, got {:?}", other),
724 } else if let Ref(data_ptr, Some(meta), _) = op.val {
725 // by-value dynamic dispatch
726 llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(&mut bx, meta, &fn_abi));
727 llargs.push(data_ptr);
730 span_bug!(span, "can't codegen a virtual call on {:?}", op);
734 // The callee needs to own the argument memory if we pass it
735 // by-ref, so make a local copy of non-immediate constants.
736 match (arg, op.val) {
737 (&mir::Operand::Copy(_), Ref(_, None, _))
738 | (&mir::Operand::Constant(_), Ref(_, None, _)) => {
739 let tmp = PlaceRef::alloca(&mut bx, op.layout);
740 op.val.store(&mut bx, tmp);
741 op.val = Ref(tmp.llval, None, tmp.align);
746 self.codegen_argument(&mut bx, op, &mut llargs, &fn_abi.args[i]);
748 if let Some(tup) = untuple {
749 self.codegen_arguments_untupled(
753 &fn_abi.args[first_args.len()..],
758 instance.map_or(false, |i| i.def.requires_caller_location(self.cx.tcx()));
763 "#[track_caller] fn's must have 1 more argument in their ABI than in their MIR",
766 self.get_caller_location(&mut bx, mir::SourceInfo { span: fn_span, ..source_info });
768 "codegen_call_terminator({:?}): location={:?} (fn_span {:?})",
769 terminator, location, fn_span
772 let last_arg = fn_abi.args.last().unwrap();
773 self.codegen_argument(&mut bx, location, &mut llargs, last_arg);
776 let fn_ptr = match (llfn, instance) {
777 (Some(llfn), _) => llfn,
778 (None, Some(instance)) => bx.get_fn_addr(instance),
779 _ => span_bug!(span, "no llfn for call"),
788 destination.as_ref().map(|&(_, target)| (ret_dest, target)),
793 fn codegen_asm_terminator(
795 helper: TerminatorCodegenHelper<'tcx>,
797 terminator: &mir::Terminator<'tcx>,
798 template: &[ast::InlineAsmTemplatePiece],
799 operands: &[mir::InlineAsmOperand<'tcx>],
800 options: ast::InlineAsmOptions,
802 destination: Option<mir::BasicBlock>,
804 let span = terminator.source_info.span;
806 let operands: Vec<_> = operands
808 .map(|op| match *op {
809 mir::InlineAsmOperand::In { reg, ref value } => {
810 let value = self.codegen_operand(&mut bx, value);
811 InlineAsmOperandRef::In { reg, value }
813 mir::InlineAsmOperand::Out { reg, late, ref place } => {
814 let place = place.map(|place| self.codegen_place(&mut bx, place.as_ref()));
815 InlineAsmOperandRef::Out { reg, late, place }
817 mir::InlineAsmOperand::InOut { reg, late, ref in_value, ref out_place } => {
818 let in_value = self.codegen_operand(&mut bx, in_value);
820 out_place.map(|out_place| self.codegen_place(&mut bx, out_place.as_ref()));
821 InlineAsmOperandRef::InOut { reg, late, in_value, out_place }
823 mir::InlineAsmOperand::Const { ref value } => {
824 let const_value = self
825 .eval_mir_constant(value)
826 .unwrap_or_else(|_| span_bug!(span, "asm const cannot be resolved"));
827 let string = common::asm_const_to_str(
831 bx.layout_of(value.ty()),
833 InlineAsmOperandRef::Const { string }
835 mir::InlineAsmOperand::SymFn { ref value } => {
836 let literal = self.monomorphize(value.literal);
837 if let ty::FnDef(def_id, substs) = *literal.ty().kind() {
838 let instance = ty::Instance::resolve_for_fn_ptr(
840 ty::ParamEnv::reveal_all(),
845 InlineAsmOperandRef::SymFn { instance }
847 span_bug!(span, "invalid type for asm sym (fn)");
850 mir::InlineAsmOperand::SymStatic { def_id } => {
851 InlineAsmOperandRef::SymStatic { def_id }
856 bx.codegen_inline_asm(template, &operands, options, line_spans);
858 if let Some(target) = destination {
859 helper.funclet_br(self, &mut bx, target);
866 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
867 pub fn codegen_block(&mut self, bb: mir::BasicBlock) {
868 let mut bx = self.build_block(bb);
872 debug!("codegen_block({:?}={:?})", bb, data);
874 for statement in &data.statements {
875 bx = self.codegen_statement(bx, statement);
878 self.codegen_terminator(bx, bb, data.terminator());
881 fn codegen_terminator(
885 terminator: &'tcx mir::Terminator<'tcx>,
887 debug!("codegen_terminator: {:?}", terminator);
889 // Create the cleanup bundle, if needed.
890 let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
891 let helper = TerminatorCodegenHelper { bb, terminator, funclet_bb };
893 self.set_debug_loc(&mut bx, terminator.source_info);
894 match terminator.kind {
895 mir::TerminatorKind::Resume => self.codegen_resume_terminator(helper, bx),
897 mir::TerminatorKind::Abort => {
899 // `abort` does not terminate the block, so we still need to generate
900 // an `unreachable` terminator after it.
904 mir::TerminatorKind::Goto { target } => {
906 // This is an unconditional branch back to this same basic block. That means we
907 // have something like a `loop {}` statement. LLVM versions before 12.0
908 // miscompile this because they assume forward progress. For older versions
909 // try to handle just this specific case which comes up commonly in practice
910 // (e.g., in embedded code).
912 // NB: the `sideeffect` currently checks for the LLVM version used internally.
916 helper.funclet_br(self, &mut bx, target);
919 mir::TerminatorKind::SwitchInt { ref discr, switch_ty, ref targets } => {
920 self.codegen_switchint_terminator(helper, bx, discr, switch_ty, targets);
923 mir::TerminatorKind::Return => {
924 self.codegen_return_terminator(bx);
927 mir::TerminatorKind::Unreachable => {
931 mir::TerminatorKind::Drop { place, target, unwind } => {
932 self.codegen_drop_terminator(helper, bx, place, target, unwind);
935 mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
936 self.codegen_assert_terminator(
937 helper, bx, terminator, cond, expected, msg, target, cleanup,
941 mir::TerminatorKind::DropAndReplace { .. } => {
942 bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
945 mir::TerminatorKind::Call {
953 self.codegen_call_terminator(
964 mir::TerminatorKind::GeneratorDrop | mir::TerminatorKind::Yield { .. } => {
965 bug!("generator ops in codegen")
967 mir::TerminatorKind::FalseEdge { .. } | mir::TerminatorKind::FalseUnwind { .. } => {
968 bug!("borrowck false edges in codegen")
971 mir::TerminatorKind::InlineAsm {
978 self.codegen_asm_terminator(
995 op: OperandRef<'tcx, Bx::Value>,
996 llargs: &mut Vec<Bx::Value>,
997 arg: &ArgAbi<'tcx, Ty<'tcx>>,
999 // Fill padding with undef value, where applicable.
1000 if let Some(ty) = arg.pad {
1001 llargs.push(bx.const_undef(bx.reg_backend_type(&ty)))
1004 if arg.is_ignore() {
1008 if let PassMode::Pair(..) = arg.mode {
1015 _ => bug!("codegen_argument: {:?} invalid for pair argument", op),
1017 } else if arg.is_unsized_indirect() {
1019 Ref(a, Some(b), _) => {
1024 _ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op),
1028 // Force by-ref if we have to load through a cast pointer.
1029 let (mut llval, align, by_ref) = match op.val {
1030 Immediate(_) | Pair(..) => match arg.mode {
1031 PassMode::Indirect { .. } | PassMode::Cast(_) => {
1032 let scratch = PlaceRef::alloca(bx, arg.layout);
1033 op.val.store(bx, scratch);
1034 (scratch.llval, scratch.align, true)
1036 _ => (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false),
1038 Ref(llval, _, align) => {
1039 if arg.is_indirect() && align < arg.layout.align.abi {
1040 // `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I
1041 // think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't
1042 // have scary latent bugs around.
1044 let scratch = PlaceRef::alloca(bx, arg.layout);
1054 (scratch.llval, scratch.align, true)
1056 (llval, align, true)
1061 if by_ref && !arg.is_indirect() {
1062 // Have to load the argument, maybe while casting it.
1063 if let PassMode::Cast(ty) = arg.mode {
1064 let addr = bx.pointercast(llval, bx.type_ptr_to(bx.cast_backend_type(&ty)));
1065 llval = bx.load(addr, align.min(arg.layout.align.abi));
1067 // We can't use `PlaceRef::load` here because the argument
1068 // may have a type we don't treat as immediate, but the ABI
1069 // used for this call is passing it by-value. In that case,
1070 // the load would just produce `OperandValue::Ref` instead
1071 // of the `OperandValue::Immediate` we need for the call.
1072 llval = bx.load(llval, align);
1073 if let abi::Abi::Scalar(ref scalar) = arg.layout.abi {
1074 if scalar.is_bool() {
1075 bx.range_metadata(llval, 0..2);
1078 // We store bools as `i8` so we need to truncate to `i1`.
1079 llval = bx.to_immediate(llval, arg.layout);
1086 fn codegen_arguments_untupled(
1089 operand: &mir::Operand<'tcx>,
1090 llargs: &mut Vec<Bx::Value>,
1091 args: &[ArgAbi<'tcx, Ty<'tcx>>],
1093 let tuple = self.codegen_operand(bx, operand);
1095 // Handle both by-ref and immediate tuples.
1096 if let Ref(llval, None, align) = tuple.val {
1097 let tuple_ptr = PlaceRef::new_sized_aligned(llval, tuple.layout, align);
1098 for i in 0..tuple.layout.fields.count() {
1099 let field_ptr = tuple_ptr.project_field(bx, i);
1100 let field = bx.load_operand(field_ptr);
1101 self.codegen_argument(bx, field, llargs, &args[i]);
1103 } else if let Ref(_, Some(_), _) = tuple.val {
1104 bug!("closure arguments must be sized")
1106 // If the tuple is immediate, the elements are as well.
1107 for i in 0..tuple.layout.fields.count() {
1108 let op = tuple.extract_field(bx, i);
1109 self.codegen_argument(bx, op, llargs, &args[i]);
1114 fn get_caller_location(
1117 mut source_info: mir::SourceInfo,
1118 ) -> OperandRef<'tcx, Bx::Value> {
1121 let mut span_to_caller_location = |span: Span| {
1122 let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
1123 let caller = tcx.sess.source_map().lookup_char_pos(topmost.lo());
1124 let const_loc = tcx.const_caller_location((
1125 Symbol::intern(&caller.file.name.prefer_remapped().to_string_lossy()),
1127 caller.col_display as u32 + 1,
1129 OperandRef::from_const(bx, const_loc, bx.tcx().caller_location_ty())
1132 // Walk up the `SourceScope`s, in case some of them are from MIR inlining.
1133 // If so, the starting `source_info.span` is in the innermost inlined
1134 // function, and will be replaced with outer callsite spans as long
1135 // as the inlined functions were `#[track_caller]`.
1137 let scope_data = &self.mir.source_scopes[source_info.scope];
1139 if let Some((callee, callsite_span)) = scope_data.inlined {
1140 // Stop inside the most nested non-`#[track_caller]` function,
1141 // before ever reaching its caller (which is irrelevant).
1142 if !callee.def.requires_caller_location(tcx) {
1143 return span_to_caller_location(source_info.span);
1145 source_info.span = callsite_span;
1148 // Skip past all of the parents with `inlined: None`.
1149 match scope_data.inlined_parent_scope {
1150 Some(parent) => source_info.scope = parent,
1155 // No inlined `SourceScope`s, or all of them were `#[track_caller]`.
1156 self.caller_location.unwrap_or_else(|| span_to_caller_location(source_info.span))
1159 fn get_personality_slot(&mut self, bx: &mut Bx) -> PlaceRef<'tcx, Bx::Value> {
1161 if let Some(slot) = self.personality_slot {
1164 let layout = cx.layout_of(
1165 cx.tcx().intern_tup(&[cx.tcx().mk_mut_ptr(cx.tcx().types.u8), cx.tcx().types.i32]),
1167 let slot = PlaceRef::alloca(bx, layout);
1168 self.personality_slot = Some(slot);
1173 /// Returns the landing-pad wrapper around the given basic block.
1175 /// No-op in MSVC SEH scheme.
1176 fn landing_pad_to(&mut self, target_bb: mir::BasicBlock) -> Bx::BasicBlock {
1177 if let Some(block) = self.landing_pads[target_bb] {
1181 let block = self.blocks[target_bb];
1182 let landing_pad = self.landing_pad_uncached(block);
1183 self.landing_pads[target_bb] = Some(landing_pad);
1187 fn landing_pad_uncached(&mut self, target_bb: Bx::BasicBlock) -> Bx::BasicBlock {
1188 if base::wants_msvc_seh(self.cx.sess()) {
1189 span_bug!(self.mir.span, "landing pad was not inserted?")
1192 let mut bx = self.new_block("cleanup");
1194 let llpersonality = self.cx.eh_personality();
1195 let llretty = self.landing_pad_type();
1196 let lp = bx.landing_pad(llretty, llpersonality, 1);
1199 let slot = self.get_personality_slot(&mut bx);
1200 slot.storage_live(&mut bx);
1201 Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot);
1207 fn landing_pad_type(&self) -> Bx::Type {
1209 cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
1212 fn unreachable_block(&mut self) -> Bx::BasicBlock {
1213 self.unreachable_block.unwrap_or_else(|| {
1214 let mut bx = self.new_block("unreachable");
1216 self.unreachable_block = Some(bx.llbb());
1221 pub fn new_block(&self, name: &str) -> Bx {
1222 Bx::new_block(self.cx, self.llfn, name)
1225 pub fn build_block(&self, bb: mir::BasicBlock) -> Bx {
1226 let mut bx = Bx::with_cx(self.cx);
1227 bx.position_at_end(self.blocks[bb]);
1231 fn make_return_dest(
1234 dest: mir::Place<'tcx>,
1235 fn_ret: &ArgAbi<'tcx, Ty<'tcx>>,
1236 llargs: &mut Vec<Bx::Value>,
1238 ) -> ReturnDest<'tcx, Bx::Value> {
1239 // If the return is ignored, we can just return a do-nothing `ReturnDest`.
1240 if fn_ret.is_ignore() {
1241 return ReturnDest::Nothing;
1243 let dest = if let Some(index) = dest.as_local() {
1244 match self.locals[index] {
1245 LocalRef::Place(dest) => dest,
1246 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
1247 LocalRef::Operand(None) => {
1248 // Handle temporary places, specifically `Operand` ones, as
1249 // they don't have `alloca`s.
1250 return if fn_ret.is_indirect() {
1251 // Odd, but possible, case, we have an operand temporary,
1252 // but the calling convention has an indirect return.
1253 let tmp = PlaceRef::alloca(bx, fn_ret.layout);
1254 tmp.storage_live(bx);
1255 llargs.push(tmp.llval);
1256 ReturnDest::IndirectOperand(tmp, index)
1257 } else if is_intrinsic {
1258 // Currently, intrinsics always need a location to store
1259 // the result, so we create a temporary `alloca` for the
1261 let tmp = PlaceRef::alloca(bx, fn_ret.layout);
1262 tmp.storage_live(bx);
1263 ReturnDest::IndirectOperand(tmp, index)
1265 ReturnDest::DirectOperand(index)
1268 LocalRef::Operand(Some(_)) => {
1269 bug!("place local already assigned to");
1275 mir::PlaceRef { local: dest.local, projection: &dest.projection },
1278 if fn_ret.is_indirect() {
1279 if dest.align < dest.layout.align.abi {
1280 // Currently, MIR code generation does not create calls
1281 // that store directly to fields of packed structs (in
1282 // fact, the calls it creates write only to temps).
1284 // If someone changes that, please update this code path
1285 // to create a temporary.
1286 span_bug!(self.mir.span, "can't directly store to unaligned value");
1288 llargs.push(dest.llval);
1291 ReturnDest::Store(dest)
1295 fn codegen_transmute(&mut self, bx: &mut Bx, src: &mir::Operand<'tcx>, dst: mir::Place<'tcx>) {
1296 if let Some(index) = dst.as_local() {
1297 match self.locals[index] {
1298 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
1299 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
1300 LocalRef::Operand(None) => {
1301 let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst.as_ref()));
1302 assert!(!dst_layout.ty.has_erasable_regions());
1303 let place = PlaceRef::alloca(bx, dst_layout);
1304 place.storage_live(bx);
1305 self.codegen_transmute_into(bx, src, place);
1306 let op = bx.load_operand(place);
1307 place.storage_dead(bx);
1308 self.locals[index] = LocalRef::Operand(Some(op));
1309 self.debug_introduce_local(bx, index);
1311 LocalRef::Operand(Some(op)) => {
1312 assert!(op.layout.is_zst(), "assigning to initialized SSAtemp");
1316 let dst = self.codegen_place(bx, dst.as_ref());
1317 self.codegen_transmute_into(bx, src, dst);
1321 fn codegen_transmute_into(
1324 src: &mir::Operand<'tcx>,
1325 dst: PlaceRef<'tcx, Bx::Value>,
1327 let src = self.codegen_operand(bx, src);
1329 // Special-case transmutes between scalars as simple bitcasts.
1330 match (&src.layout.abi, &dst.layout.abi) {
1331 (abi::Abi::Scalar(src_scalar), abi::Abi::Scalar(dst_scalar)) => {
1332 // HACK(eddyb) LLVM doesn't like `bitcast`s between pointers and non-pointers.
1333 if (src_scalar.value == abi::Pointer) == (dst_scalar.value == abi::Pointer) {
1334 assert_eq!(src.layout.size, dst.layout.size);
1336 // NOTE(eddyb) the `from_immediate` and `to_immediate_scalar`
1337 // conversions allow handling `bool`s the same as `u8`s.
1338 let src = bx.from_immediate(src.immediate());
1339 let src_as_dst = bx.bitcast(src, bx.backend_type(dst.layout));
1340 Immediate(bx.to_immediate_scalar(src_as_dst, dst_scalar)).store(bx, dst);
1347 let llty = bx.backend_type(src.layout);
1348 let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty));
1349 let align = src.layout.align.abi.min(dst.align);
1350 src.val.store(bx, PlaceRef::new_sized_aligned(cast_ptr, src.layout, align));
1353 // Stores the return value of a function call into it's final location.
1357 dest: ReturnDest<'tcx, Bx::Value>,
1358 ret_abi: &ArgAbi<'tcx, Ty<'tcx>>,
1361 use self::ReturnDest::*;
1365 Store(dst) => bx.store_arg(&ret_abi, llval, dst),
1366 IndirectOperand(tmp, index) => {
1367 let op = bx.load_operand(tmp);
1368 tmp.storage_dead(bx);
1369 self.locals[index] = LocalRef::Operand(Some(op));
1370 self.debug_introduce_local(bx, index);
1372 DirectOperand(index) => {
1373 // If there is a cast, we have to store and reload.
1374 let op = if let PassMode::Cast(_) = ret_abi.mode {
1375 let tmp = PlaceRef::alloca(bx, ret_abi.layout);
1376 tmp.storage_live(bx);
1377 bx.store_arg(&ret_abi, llval, tmp);
1378 let op = bx.load_operand(tmp);
1379 tmp.storage_dead(bx);
1382 OperandRef::from_immediate_or_packed_pair(bx, llval, ret_abi.layout)
1384 self.locals[index] = LocalRef::Operand(Some(op));
1385 self.debug_introduce_local(bx, index);
1391 enum ReturnDest<'tcx, V> {
1392 // Do nothing; the return value is indirect or ignored.
1394 // Store the return value to the pointer.
1395 Store(PlaceRef<'tcx, V>),
1396 // Store an indirect return value to an operand local place.
1397 IndirectOperand(PlaceRef<'tcx, V>, mir::Local),
1398 // Store a direct return value to an operand local place.
1399 DirectOperand(mir::Local),