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_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
14 use rustc_hir::lang_items::LangItem;
15 use rustc_index::vec::Idx;
16 use rustc_middle::mir::{self, AssertKind, SwitchTargets};
17 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
18 use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths};
19 use rustc_middle::ty::{self, Instance, Ty, TypeVisitable};
20 use rustc_span::source_map::Span;
21 use rustc_span::{sym, Symbol};
22 use rustc_symbol_mangling::typeid::typeid_for_fnabi;
23 use rustc_target::abi::call::{ArgAbi, FnAbi, PassMode, Reg};
24 use rustc_target::abi::{self, HasDataLayout, WrappingRange};
25 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 appropriate `Funclet` for the current funclet, if on MSVC,
37 /// either already previously cached, or newly created, by `landing_pad_for`.
38 fn funclet<'b, Bx: BuilderMethods<'a, 'tcx>>(
40 fx: &'b mut FunctionCx<'a, 'tcx, Bx>,
41 ) -> Option<&'b Bx::Funclet> {
42 let funclet_bb = self.funclet_bb?;
43 if base::wants_msvc_seh(fx.cx.tcx().sess) {
44 // If `landing_pad_for` hasn't been called yet to create the `Funclet`,
45 // it has to be now. This may not seem necessary, as RPO should lead
46 // to all the unwind edges being visited (and so to `landing_pad_for`
47 // getting called for them), before building any of the blocks inside
48 // the funclet itself - however, if MIR contains edges that end up not
49 // being needed in the LLVM IR after monomorphization, the funclet may
50 // be unreachable, and we don't have yet a way to skip building it in
51 // such an eventuality (which may be a better solution than this).
52 if fx.funclets[funclet_bb].is_none() {
53 fx.landing_pad_for(funclet_bb);
57 fx.funclets[funclet_bb]
59 .expect("landing_pad_for didn't also create funclets entry"),
66 fn lltarget<Bx: BuilderMethods<'a, 'tcx>>(
68 fx: &mut FunctionCx<'a, 'tcx, Bx>,
69 target: mir::BasicBlock,
70 ) -> (Bx::BasicBlock, bool) {
71 let span = self.terminator.source_info.span;
72 let lltarget = fx.llbb(target);
73 let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
74 match (self.funclet_bb, target_funclet) {
75 (None, None) => (lltarget, false),
76 (Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) => {
79 // jump *into* cleanup - need a landing pad if GNU, cleanup pad if MSVC
80 (None, Some(_)) => (fx.landing_pad_for(target), false),
81 (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
82 (Some(_), Some(_)) => (fx.landing_pad_for(target), true),
86 /// Create a basic block.
87 fn llblock<Bx: BuilderMethods<'a, 'tcx>>(
89 fx: &mut FunctionCx<'a, 'tcx, Bx>,
90 target: mir::BasicBlock,
92 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
94 // MSVC cross-funclet jump - need a trampoline
96 debug!("llblock: creating cleanup trampoline for {:?}", target);
97 let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
98 let trampoline_llbb = Bx::append_block(fx.cx, fx.llfn, name);
99 let mut trampoline_bx = Bx::build(fx.cx, trampoline_llbb);
100 trampoline_bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
107 fn funclet_br<Bx: BuilderMethods<'a, 'tcx>>(
109 fx: &mut FunctionCx<'a, 'tcx, Bx>,
111 target: mir::BasicBlock,
113 let (lltarget, is_cleanupret) = self.lltarget(fx, target);
115 // micro-optimization: generate a `ret` rather than a jump
117 bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
123 /// Call `fn_ptr` of `fn_abi` with the arguments `llargs`, the optional
124 /// return destination `destination` and the cleanup function `cleanup`.
125 fn do_call<Bx: BuilderMethods<'a, 'tcx>>(
127 fx: &mut FunctionCx<'a, 'tcx, Bx>,
129 fn_abi: &'tcx FnAbi<'tcx, Ty<'tcx>>,
131 llargs: &[Bx::Value],
132 destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>,
133 cleanup: Option<mir::BasicBlock>,
134 copied_constant_arguments: &[PlaceRef<'tcx, <Bx as BackendTypes>::Value>],
136 // If there is a cleanup block and the function we're calling can unwind, then
137 // do an invoke, otherwise do a call.
138 let fn_ty = bx.fn_decl_backend_type(&fn_abi);
140 let unwind_block = if let Some(cleanup) = cleanup.filter(|_| fn_abi.can_unwind) {
141 Some(self.llblock(fx, cleanup))
142 } else if fx.mir[self.bb].is_cleanup
144 && !base::wants_msvc_seh(fx.cx.tcx().sess)
146 // Exception must not propagate out of the execution of a cleanup (doing so
147 // can cause undefined behaviour). We insert a double unwind guard for
148 // functions that can potentially unwind to protect against this.
150 // This is not necessary for SEH which does not use successive unwinding
151 // like Itanium EH. EH frames in SEH are different from normal function
152 // frames and SEH will abort automatically if an exception tries to
153 // propagate out from cleanup.
154 Some(fx.double_unwind_guard())
159 if let Some(unwind_block) = unwind_block {
160 let ret_llbb = if let Some((_, target)) = destination {
163 fx.unreachable_block()
165 let invokeret = bx.invoke(
174 if fx.mir[self.bb].is_cleanup {
175 bx.do_not_inline(invokeret);
178 if let Some((ret_dest, target)) = destination {
179 bx.switch_to_block(fx.llbb(target));
180 fx.set_debug_loc(bx, self.terminator.source_info);
181 for tmp in copied_constant_arguments {
182 bx.lifetime_end(tmp.llval, tmp.layout.size);
184 fx.store_return(bx, ret_dest, &fn_abi.ret, invokeret);
187 let llret = bx.call(fn_ty, Some(&fn_abi), fn_ptr, &llargs, self.funclet(fx));
188 if fx.mir[self.bb].is_cleanup {
189 // Cleanup is always the cold path. Don't inline
190 // drop glue. Also, when there is a deeply-nested
191 // struct, there are "symmetry" issues that cause
192 // exponential inlining - see issue #41696.
193 bx.do_not_inline(llret);
196 if let Some((ret_dest, target)) = destination {
197 for tmp in copied_constant_arguments {
198 bx.lifetime_end(tmp.llval, tmp.layout.size);
200 fx.store_return(bx, ret_dest, &fn_abi.ret, llret);
201 self.funclet_br(fx, bx, target);
208 /// Generates inline assembly with optional `destination` and `cleanup`.
209 fn do_inlineasm<Bx: BuilderMethods<'a, 'tcx>>(
211 fx: &mut FunctionCx<'a, 'tcx, Bx>,
213 template: &[InlineAsmTemplatePiece],
214 operands: &[InlineAsmOperandRef<'tcx, Bx>],
215 options: InlineAsmOptions,
217 destination: Option<mir::BasicBlock>,
218 cleanup: Option<mir::BasicBlock>,
219 instance: Instance<'_>,
221 if let Some(cleanup) = cleanup {
222 let ret_llbb = if let Some(target) = destination {
225 fx.unreachable_block()
228 bx.codegen_inline_asm(
234 Some((ret_llbb, self.llblock(fx, cleanup), self.funclet(fx))),
237 bx.codegen_inline_asm(template, &operands, options, line_spans, instance, None);
239 if let Some(target) = destination {
240 self.funclet_br(fx, bx, target);
248 /// Codegen implementations for some terminator variants.
249 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
250 /// Generates code for a `Resume` terminator.
251 fn codegen_resume_terminator(&mut self, helper: TerminatorCodegenHelper<'tcx>, mut bx: Bx) {
252 if let Some(funclet) = helper.funclet(self) {
253 bx.cleanup_ret(funclet, None);
255 let slot = self.get_personality_slot(&mut bx);
256 let lp0 = slot.project_field(&mut bx, 0);
257 let lp0 = bx.load_operand(lp0).immediate();
258 let lp1 = slot.project_field(&mut bx, 1);
259 let lp1 = bx.load_operand(lp1).immediate();
260 slot.storage_dead(&mut bx);
262 let mut lp = bx.const_undef(self.landing_pad_type());
263 lp = bx.insert_value(lp, lp0, 0);
264 lp = bx.insert_value(lp, lp1, 1);
269 fn codegen_switchint_terminator(
271 helper: TerminatorCodegenHelper<'tcx>,
273 discr: &mir::Operand<'tcx>,
275 targets: &SwitchTargets,
277 let discr = self.codegen_operand(&mut bx, &discr);
278 // `switch_ty` is redundant, sanity-check that.
279 assert_eq!(discr.layout.ty, switch_ty);
280 let mut target_iter = targets.iter();
281 if target_iter.len() == 1 {
282 // If there are two targets (one conditional, one fallback), emit br instead of switch
283 let (test_value, target) = target_iter.next().unwrap();
284 let lltrue = helper.llblock(self, target);
285 let llfalse = helper.llblock(self, targets.otherwise());
286 if switch_ty == bx.tcx().types.bool {
287 // Don't generate trivial icmps when switching on bool
289 0 => bx.cond_br(discr.immediate(), llfalse, lltrue),
290 1 => bx.cond_br(discr.immediate(), lltrue, llfalse),
294 let switch_llty = bx.immediate_backend_type(bx.layout_of(switch_ty));
295 let llval = bx.const_uint_big(switch_llty, test_value);
296 let cmp = bx.icmp(IntPredicate::IntEQ, discr.immediate(), llval);
297 bx.cond_br(cmp, lltrue, llfalse);
302 helper.llblock(self, targets.otherwise()),
303 target_iter.map(|(value, target)| (value, helper.llblock(self, target))),
308 fn codegen_return_terminator(&mut self, mut bx: Bx) {
309 // Call `va_end` if this is the definition of a C-variadic function.
310 if self.fn_abi.c_variadic {
311 // The `VaList` "spoofed" argument is just after all the real arguments.
312 let va_list_arg_idx = self.fn_abi.args.len();
313 match self.locals[mir::Local::new(1 + va_list_arg_idx)] {
314 LocalRef::Place(va_list) => {
315 bx.va_end(va_list.llval);
317 _ => bug!("C-variadic function must have a `VaList` place"),
320 if self.fn_abi.ret.layout.abi.is_uninhabited() {
321 // Functions with uninhabited return values are marked `noreturn`,
322 // so we should make sure that we never actually do.
323 // We play it safe by using a well-defined `abort`, but we could go for immediate UB
324 // if that turns out to be helpful.
326 // `abort` does not terminate the block, so we still need to generate
327 // an `unreachable` terminator after it.
331 let llval = match &self.fn_abi.ret.mode {
332 PassMode::Ignore | PassMode::Indirect { .. } => {
337 PassMode::Direct(_) | PassMode::Pair(..) => {
338 let op = self.codegen_consume(&mut bx, mir::Place::return_place().as_ref());
339 if let Ref(llval, _, align) = op.val {
340 bx.load(bx.backend_type(op.layout), llval, align)
342 op.immediate_or_packed_pair(&mut bx)
346 PassMode::Cast(cast_ty, _) => {
347 let op = match self.locals[mir::RETURN_PLACE] {
348 LocalRef::Operand(Some(op)) => op,
349 LocalRef::Operand(None) => bug!("use of return before def"),
350 LocalRef::Place(cg_place) => OperandRef {
351 val: Ref(cg_place.llval, None, cg_place.align),
352 layout: cg_place.layout,
354 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
356 let llslot = match op.val {
357 Immediate(_) | Pair(..) => {
358 let scratch = PlaceRef::alloca(&mut bx, self.fn_abi.ret.layout);
359 op.val.store(&mut bx, scratch);
362 Ref(llval, _, align) => {
363 assert_eq!(align, op.layout.align.abi, "return place is unaligned!");
367 let ty = bx.cast_backend_type(cast_ty);
368 let addr = bx.pointercast(llslot, bx.type_ptr_to(ty));
369 bx.load(ty, addr, self.fn_abi.ret.layout.align.abi)
375 #[tracing::instrument(level = "trace", skip(self, helper, bx))]
376 fn codegen_drop_terminator(
378 helper: TerminatorCodegenHelper<'tcx>,
380 location: mir::Place<'tcx>,
381 target: mir::BasicBlock,
382 unwind: Option<mir::BasicBlock>,
384 let ty = location.ty(self.mir, bx.tcx()).ty;
385 let ty = self.monomorphize(ty);
386 let drop_fn = Instance::resolve_drop_in_place(bx.tcx(), ty);
388 if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
389 // we don't actually need to drop anything.
390 helper.funclet_br(self, &mut bx, target);
394 let place = self.codegen_place(&mut bx, location.as_ref());
396 let mut args = if let Some(llextra) = place.llextra {
397 args2 = [place.llval, llextra];
400 args1 = [place.llval];
403 let (drop_fn, fn_abi) = match ty.kind() {
404 // FIXME(eddyb) perhaps move some of this logic into
405 // `Instance::resolve_drop_in_place`?
406 ty::Dynamic(_, _, ty::Dyn) => {
407 // IN THIS ARM, WE HAVE:
408 // ty = *mut (dyn Trait)
409 // which is: exists<T> ( *mut T, Vtable<T: Trait> )
412 // args = ( Data, Vtable )
419 let virtual_drop = Instance {
420 def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
421 substs: drop_fn.substs,
423 debug!("ty = {:?}", ty);
424 debug!("drop_fn = {:?}", drop_fn);
425 debug!("args = {:?}", args);
426 let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty());
427 let vtable = args[1];
428 // Truncate vtable off of args list
431 meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE)
432 .get_fn(&mut bx, vtable, ty, &fn_abi),
436 ty::Dynamic(_, _, ty::DynStar) => {
437 // IN THIS ARM, WE HAVE:
438 // ty = *mut (dyn* Trait)
439 // which is: *mut exists<T: sizeof(T) == sizeof(usize)> (T, Vtable<T: Trait>)
452 // WE CAN CONVERT THIS INTO THE ABOVE LOGIC BY DOING
454 // data = &(*args[0]).0 // gives a pointer to Data above (really the same pointer)
455 // vtable = (*args[0]).1 // loads the vtable out
456 // (data, vtable) // an equivalent Rust `*mut dyn Trait`
458 // SO THEN WE CAN USE THE ABOVE CODE.
459 let virtual_drop = Instance {
460 def: ty::InstanceDef::Virtual(drop_fn.def_id(), 0),
461 substs: drop_fn.substs,
463 debug!("ty = {:?}", ty);
464 debug!("drop_fn = {:?}", drop_fn);
465 debug!("args = {:?}", args);
466 let fn_abi = bx.fn_abi_of_instance(virtual_drop, ty::List::empty());
468 let data_ty = bx.cx().backend_type(place.layout);
470 bx.gep(data_ty, data, &[bx.cx().const_i32(0), bx.cx().const_i32(1)]);
471 let vtable = bx.load(bx.type_i8p(), vtable_ptr, abi::Align::ONE);
472 // Truncate vtable off of args list
474 debug!("args' = {:?}", args);
476 meth::VirtualIndex::from_index(ty::COMMON_VTABLE_ENTRIES_DROPINPLACE)
477 .get_fn(&mut bx, vtable, ty, &fn_abi),
481 _ => (bx.get_fn_addr(drop_fn), bx.fn_abi_of_instance(drop_fn, ty::List::empty())),
489 Some((ReturnDest::Nothing, target)),
495 fn codegen_assert_terminator(
497 helper: TerminatorCodegenHelper<'tcx>,
499 terminator: &mir::Terminator<'tcx>,
500 cond: &mir::Operand<'tcx>,
502 msg: &mir::AssertMessage<'tcx>,
503 target: mir::BasicBlock,
504 cleanup: Option<mir::BasicBlock>,
506 let span = terminator.source_info.span;
507 let cond = self.codegen_operand(&mut bx, cond).immediate();
508 let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
510 // This case can currently arise only from functions marked
511 // with #[rustc_inherit_overflow_checks] and inlined from
512 // another crate (mostly core::num generic/#[inline] fns),
513 // while the current crate doesn't use overflow checks.
514 // NOTE: Unlike binops, negation doesn't have its own
515 // checked operation, just a comparison with the minimum
516 // value, so we have to check for the assert message.
517 if !bx.check_overflow() {
518 if let AssertKind::OverflowNeg(_) = *msg {
519 const_cond = Some(expected);
523 // Don't codegen the panic block if success if known.
524 if const_cond == Some(expected) {
525 helper.funclet_br(self, &mut bx, target);
529 // Pass the condition through llvm.expect for branch hinting.
530 let cond = bx.expect(cond, expected);
532 // Create the failure block and the conditional branch to it.
533 let lltarget = helper.llblock(self, target);
534 let panic_block = bx.append_sibling_block("panic");
536 bx.cond_br(cond, lltarget, panic_block);
538 bx.cond_br(cond, panic_block, lltarget);
541 // After this point, bx is the block for the call to panic.
542 bx.switch_to_block(panic_block);
543 self.set_debug_loc(&mut bx, terminator.source_info);
545 // Get the location information.
546 let location = self.get_caller_location(&mut bx, terminator.source_info).immediate();
548 // Put together the arguments to the panic entry point.
549 let (lang_item, args) = match msg {
550 AssertKind::BoundsCheck { ref len, ref index } => {
551 let len = self.codegen_operand(&mut bx, len).immediate();
552 let index = self.codegen_operand(&mut bx, index).immediate();
553 // It's `fn panic_bounds_check(index: usize, len: usize)`,
554 // and `#[track_caller]` adds an implicit third argument.
555 (LangItem::PanicBoundsCheck, vec![index, len, location])
558 let msg = bx.const_str(msg.description());
559 // It's `pub fn panic(expr: &str)`, with the wide reference being passed
560 // as two arguments, and `#[track_caller]` adds an implicit third argument.
561 (LangItem::Panic, vec![msg.0, msg.1, location])
565 let (fn_abi, llfn) = common::build_langcall(&bx, Some(span), lang_item);
567 // Codegen the actual panic invoke/call.
568 helper.do_call(self, &mut bx, fn_abi, llfn, &args, None, cleanup, &[]);
571 fn codegen_abort_terminator(
573 helper: TerminatorCodegenHelper<'tcx>,
575 terminator: &mir::Terminator<'tcx>,
577 let span = terminator.source_info.span;
578 self.set_debug_loc(&mut bx, terminator.source_info);
580 // Obtain the panic entry point.
581 let (fn_abi, llfn) = common::build_langcall(&bx, Some(span), LangItem::PanicNoUnwind);
583 // Codegen the actual panic invoke/call.
584 helper.do_call(self, &mut bx, fn_abi, llfn, &[], None, None, &[]);
587 /// Returns `true` if this is indeed a panic intrinsic and codegen is done.
588 fn codegen_panic_intrinsic(
590 helper: &TerminatorCodegenHelper<'tcx>,
592 intrinsic: Option<Symbol>,
593 instance: Option<Instance<'tcx>>,
594 source_info: mir::SourceInfo,
595 target: Option<mir::BasicBlock>,
596 cleanup: Option<mir::BasicBlock>,
598 // Emit a panic or a no-op for `assert_*` intrinsics.
599 // These are intrinsics that compile to panics so that we can get a message
600 // which mentions the offending type, even from a const context.
601 #[derive(Debug, PartialEq)]
602 enum AssertIntrinsic {
607 let panic_intrinsic = intrinsic.and_then(|i| match i {
608 sym::assert_inhabited => Some(AssertIntrinsic::Inhabited),
609 sym::assert_zero_valid => Some(AssertIntrinsic::ZeroValid),
610 sym::assert_uninit_valid => Some(AssertIntrinsic::UninitValid),
613 if let Some(intrinsic) = panic_intrinsic {
614 use AssertIntrinsic::*;
616 let ty = instance.unwrap().substs.type_at(0);
617 let layout = bx.layout_of(ty);
618 let do_panic = match intrinsic {
619 Inhabited => layout.abi.is_uninhabited(),
620 ZeroValid => !bx.tcx().permits_zero_init(layout),
621 UninitValid => !bx.tcx().permits_uninit_init(layout),
624 let msg_str = with_no_visible_paths!({
625 with_no_trimmed_paths!({
626 if layout.abi.is_uninhabited() {
627 // Use this error even for the other intrinsics as it is more precise.
628 format!("attempted to instantiate uninhabited type `{}`", ty)
629 } else if intrinsic == ZeroValid {
630 format!("attempted to zero-initialize type `{}`, which is invalid", ty)
633 "attempted to leave type `{}` uninitialized, which is invalid",
639 let msg = bx.const_str(&msg_str);
640 let location = self.get_caller_location(bx, source_info).immediate();
642 // Obtain the panic entry point.
644 common::build_langcall(bx, Some(source_info.span), LangItem::Panic);
646 // Codegen the actual panic invoke/call.
652 &[msg.0, msg.1, location],
653 target.as_ref().map(|bb| (ReturnDest::Nothing, *bb)),
659 let target = target.unwrap();
660 helper.funclet_br(self, bx, target)
668 fn codegen_call_terminator(
670 helper: TerminatorCodegenHelper<'tcx>,
672 terminator: &mir::Terminator<'tcx>,
673 func: &mir::Operand<'tcx>,
674 args: &[mir::Operand<'tcx>],
675 destination: mir::Place<'tcx>,
676 target: Option<mir::BasicBlock>,
677 cleanup: Option<mir::BasicBlock>,
680 let source_info = terminator.source_info;
681 let span = source_info.span;
683 // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
684 let callee = self.codegen_operand(&mut bx, func);
686 let (instance, mut llfn) = match *callee.layout.ty.kind() {
687 ty::FnDef(def_id, substs) => (
689 ty::Instance::resolve(bx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs)
692 .polymorphize(bx.tcx()),
696 ty::FnPtr(_) => (None, Some(callee.immediate())),
697 _ => bug!("{} is not callable", callee.layout.ty),
699 let def = instance.map(|i| i.def);
701 if let Some(ty::InstanceDef::DropGlue(_, None)) = def {
702 // Empty drop glue; a no-op.
703 let target = target.unwrap();
704 helper.funclet_br(self, &mut bx, target);
708 // FIXME(eddyb) avoid computing this if possible, when `instance` is
709 // available - right now `sig` is only needed for getting the `abi`
710 // and figuring out how many extra args were passed to a C-variadic `fn`.
711 let sig = callee.layout.ty.fn_sig(bx.tcx());
714 // Handle intrinsics old codegen wants Expr's for, ourselves.
715 let intrinsic = match def {
716 Some(ty::InstanceDef::Intrinsic(def_id)) => Some(bx.tcx().item_name(def_id)),
720 let extra_args = &args[sig.inputs().skip_binder().len()..];
721 let extra_args = bx.tcx().mk_type_list(extra_args.iter().map(|op_arg| {
722 let op_ty = op_arg.ty(self.mir, bx.tcx());
723 self.monomorphize(op_ty)
726 let fn_abi = match instance {
727 Some(instance) => bx.fn_abi_of_instance(instance, extra_args),
728 None => bx.fn_abi_of_fn_ptr(sig, extra_args),
731 if intrinsic == Some(sym::transmute) {
732 if let Some(target) = target {
733 self.codegen_transmute(&mut bx, &args[0], destination);
734 helper.funclet_br(self, &mut bx, target);
736 // If we are trying to transmute to an uninhabited type,
737 // it is likely there is no allotted destination. In fact,
738 // transmuting to an uninhabited type is UB, which means
739 // we can do what we like. Here, we declare that transmuting
740 // into an uninhabited type is impossible, so anything following
741 // it must be unreachable.
742 assert_eq!(fn_abi.ret.layout.abi, abi::Abi::Uninhabited);
748 if self.codegen_panic_intrinsic(
760 // The arguments we'll be passing. Plus one to account for outptr, if used.
761 let arg_count = fn_abi.args.len() + fn_abi.ret.is_indirect() as usize;
762 let mut llargs = Vec::with_capacity(arg_count);
764 // Prepare the return value destination
765 let ret_dest = if target.is_some() {
766 let is_intrinsic = intrinsic.is_some();
767 self.make_return_dest(&mut bx, destination, &fn_abi.ret, &mut llargs, is_intrinsic)
772 if intrinsic == Some(sym::caller_location) {
773 if let Some(target) = target {
775 .get_caller_location(&mut bx, mir::SourceInfo { span: fn_span, ..source_info });
777 if let ReturnDest::IndirectOperand(tmp, _) = ret_dest {
778 location.val.store(&mut bx, tmp);
780 self.store_return(&mut bx, ret_dest, &fn_abi.ret, location.immediate());
781 helper.funclet_br(self, &mut bx, target);
787 None | Some(sym::drop_in_place) => {}
788 Some(sym::copy_nonoverlapping) => unreachable!(),
790 let dest = match ret_dest {
791 _ if fn_abi.ret.is_indirect() => llargs[0],
792 ReturnDest::Nothing => {
793 bx.const_undef(bx.type_ptr_to(bx.arg_memory_ty(&fn_abi.ret)))
795 ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) => dst.llval,
796 ReturnDest::DirectOperand(_) => {
797 bug!("Cannot use direct operand with an intrinsic call")
801 let args: Vec<_> = args
805 // The indices passed to simd_shuffle* in the
806 // third argument must be constant. This is
807 // checked by const-qualification, which also
808 // promotes any complex rvalues to constants.
809 if i == 2 && intrinsic.as_str().starts_with("simd_shuffle") {
810 if let mir::Operand::Constant(constant) = arg {
811 let c = self.eval_mir_constant(constant);
812 let (llval, ty) = self.simd_shuffle_indices(
815 self.monomorphize(constant.ty()),
819 val: Immediate(llval),
820 layout: bx.layout_of(ty),
823 span_bug!(span, "shuffle indices must be constant");
827 self.codegen_operand(&mut bx, arg)
831 Self::codegen_intrinsic_call(
833 *instance.as_ref().unwrap(),
840 if let ReturnDest::IndirectOperand(dst, _) = ret_dest {
841 self.store_return(&mut bx, ret_dest, &fn_abi.ret, dst.llval);
844 if let Some(target) = target {
845 helper.funclet_br(self, &mut bx, target);
854 // Split the rust-call tupled arguments off.
855 let (first_args, untuple) = if abi == Abi::RustCall && !args.is_empty() {
856 let (tup, args) = args.split_last().unwrap();
862 let mut copied_constant_arguments = vec![];
863 'make_args: for (i, arg) in first_args.iter().enumerate() {
864 let mut op = self.codegen_operand(&mut bx, arg);
866 if let (0, Some(ty::InstanceDef::Virtual(_, idx))) = (i, def) {
868 Pair(data_ptr, meta) => {
869 // In the case of Rc<Self>, we need to explicitly pass a
870 // *mut RcBox<Self> with a Scalar (not ScalarPair) ABI. This is a hack
871 // that is understood elsewhere in the compiler as a method on
873 // To get a `*mut RcBox<Self>`, we just keep unwrapping newtypes until
874 // we get a value of a built-in pointer type
875 'descend_newtypes: while !op.layout.ty.is_unsafe_ptr()
876 && !op.layout.ty.is_region_ptr()
878 for i in 0..op.layout.fields.count() {
879 let field = op.extract_field(&mut bx, i);
880 if !field.layout.is_zst() {
881 // we found the one non-zero-sized field that is allowed
882 // now find *its* non-zero-sized field, or stop if it's a
885 continue 'descend_newtypes;
889 span_bug!(span, "receiver has no non-zero-sized fields {:?}", op);
892 // now that we have `*dyn Trait` or `&dyn Trait`, split it up into its
893 // data pointer and vtable. Look up the method in the vtable, and pass
894 // the data pointer as the first argument
895 llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(
901 llargs.push(data_ptr);
904 Ref(data_ptr, Some(meta), _) => {
905 // by-value dynamic dispatch
906 llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(
912 llargs.push(data_ptr);
916 let ty::Ref(_, ty, _) = op.layout.ty.kind() else {
917 span_bug!(span, "can't codegen a virtual call on {:#?}", op);
919 if !ty.is_dyn_star() {
920 span_bug!(span, "can't codegen a virtual call on {:#?}", op);
922 // FIXME(dyn-star): Make sure this is done on a &dyn* receiver
923 let place = op.deref(bx.cx());
924 let data_ptr = place.project_field(&mut bx, 0);
925 let meta_ptr = place.project_field(&mut bx, 1);
926 let meta = bx.load_operand(meta_ptr);
927 llfn = Some(meth::VirtualIndex::from_index(idx).get_fn(
933 llargs.push(data_ptr.llval);
937 span_bug!(span, "can't codegen a virtual call on {:#?}", op);
942 // The callee needs to own the argument memory if we pass it
943 // by-ref, so make a local copy of non-immediate constants.
944 match (arg, op.val) {
945 (&mir::Operand::Copy(_), Ref(_, None, _))
946 | (&mir::Operand::Constant(_), Ref(_, None, _)) => {
947 let tmp = PlaceRef::alloca(&mut bx, op.layout);
948 bx.lifetime_start(tmp.llval, tmp.layout.size);
949 op.val.store(&mut bx, tmp);
950 op.val = Ref(tmp.llval, None, tmp.align);
951 copied_constant_arguments.push(tmp);
956 self.codegen_argument(&mut bx, op, &mut llargs, &fn_abi.args[i]);
958 let num_untupled = untuple.map(|tup| {
959 self.codegen_arguments_untupled(
963 &fn_abi.args[first_args.len()..],
968 instance.map_or(false, |i| i.def.requires_caller_location(self.cx.tcx()));
970 let mir_args = if let Some(num_untupled) = num_untupled {
971 first_args.len() + num_untupled
978 "#[track_caller] fn's must have 1 more argument in their ABI than in their MIR: {:?} {:?} {:?}",
984 self.get_caller_location(&mut bx, mir::SourceInfo { span: fn_span, ..source_info });
986 "codegen_call_terminator({:?}): location={:?} (fn_span {:?})",
987 terminator, location, fn_span
990 let last_arg = fn_abi.args.last().unwrap();
991 self.codegen_argument(&mut bx, location, &mut llargs, last_arg);
994 let (is_indirect_call, fn_ptr) = match (llfn, instance) {
995 (Some(llfn), _) => (true, llfn),
996 (None, Some(instance)) => (false, bx.get_fn_addr(instance)),
997 _ => span_bug!(span, "no llfn for call"),
1000 // For backends that support CFI using type membership (i.e., testing whether a given
1001 // pointer is associated with a type identifier).
1002 if bx.tcx().sess.is_sanitizer_cfi_enabled() && is_indirect_call {
1003 // Emit type metadata and checks.
1004 // FIXME(rcvalle): Add support for generalized identifiers.
1005 // FIXME(rcvalle): Create distinct unnamed MDNodes for internal identifiers.
1006 let typeid = typeid_for_fnabi(bx.tcx(), fn_abi);
1007 let typeid_metadata = self.cx.typeid_metadata(typeid);
1009 // Test whether the function pointer is associated with the type identifier.
1010 let cond = bx.type_test(fn_ptr, typeid_metadata);
1011 let bb_pass = bx.append_sibling_block("type_test.pass");
1012 let bb_fail = bx.append_sibling_block("type_test.fail");
1013 bx.cond_br(cond, bb_pass, bb_fail);
1015 bx.switch_to_block(bb_pass);
1022 target.as_ref().map(|&target| (ret_dest, target)),
1024 &copied_constant_arguments,
1027 bx.switch_to_block(bb_fail);
1040 target.as_ref().map(|&target| (ret_dest, target)),
1042 &copied_constant_arguments,
1046 fn codegen_asm_terminator(
1048 helper: TerminatorCodegenHelper<'tcx>,
1050 terminator: &mir::Terminator<'tcx>,
1051 template: &[ast::InlineAsmTemplatePiece],
1052 operands: &[mir::InlineAsmOperand<'tcx>],
1053 options: ast::InlineAsmOptions,
1054 line_spans: &[Span],
1055 destination: Option<mir::BasicBlock>,
1056 cleanup: Option<mir::BasicBlock>,
1057 instance: Instance<'_>,
1059 let span = terminator.source_info.span;
1061 let operands: Vec<_> = operands
1063 .map(|op| match *op {
1064 mir::InlineAsmOperand::In { reg, ref value } => {
1065 let value = self.codegen_operand(&mut bx, value);
1066 InlineAsmOperandRef::In { reg, value }
1068 mir::InlineAsmOperand::Out { reg, late, ref place } => {
1069 let place = place.map(|place| self.codegen_place(&mut bx, place.as_ref()));
1070 InlineAsmOperandRef::Out { reg, late, place }
1072 mir::InlineAsmOperand::InOut { reg, late, ref in_value, ref out_place } => {
1073 let in_value = self.codegen_operand(&mut bx, in_value);
1075 out_place.map(|out_place| self.codegen_place(&mut bx, out_place.as_ref()));
1076 InlineAsmOperandRef::InOut { reg, late, in_value, out_place }
1078 mir::InlineAsmOperand::Const { ref value } => {
1079 let const_value = self
1080 .eval_mir_constant(value)
1081 .unwrap_or_else(|_| span_bug!(span, "asm const cannot be resolved"));
1082 let string = common::asm_const_to_str(
1086 bx.layout_of(value.ty()),
1088 InlineAsmOperandRef::Const { string }
1090 mir::InlineAsmOperand::SymFn { ref value } => {
1091 let literal = self.monomorphize(value.literal);
1092 if let ty::FnDef(def_id, substs) = *literal.ty().kind() {
1093 let instance = ty::Instance::resolve_for_fn_ptr(
1095 ty::ParamEnv::reveal_all(),
1100 InlineAsmOperandRef::SymFn { instance }
1102 span_bug!(span, "invalid type for asm sym (fn)");
1105 mir::InlineAsmOperand::SymStatic { def_id } => {
1106 InlineAsmOperandRef::SymStatic { def_id }
1111 helper.do_inlineasm(
1125 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
1126 pub fn codegen_block(&mut self, bb: mir::BasicBlock) {
1127 let llbb = self.llbb(bb);
1128 let mut bx = Bx::build(self.cx, llbb);
1130 let data = &mir[bb];
1132 debug!("codegen_block({:?}={:?})", bb, data);
1134 for statement in &data.statements {
1135 bx = self.codegen_statement(bx, statement);
1138 self.codegen_terminator(bx, bb, data.terminator());
1141 fn codegen_terminator(
1144 bb: mir::BasicBlock,
1145 terminator: &'tcx mir::Terminator<'tcx>,
1147 debug!("codegen_terminator: {:?}", terminator);
1149 // Create the cleanup bundle, if needed.
1150 let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
1151 let helper = TerminatorCodegenHelper { bb, terminator, funclet_bb };
1153 self.set_debug_loc(&mut bx, terminator.source_info);
1154 match terminator.kind {
1155 mir::TerminatorKind::Resume => self.codegen_resume_terminator(helper, bx),
1157 mir::TerminatorKind::Abort => {
1158 self.codegen_abort_terminator(helper, bx, terminator);
1161 mir::TerminatorKind::Goto { target } => {
1162 helper.funclet_br(self, &mut bx, target);
1165 mir::TerminatorKind::SwitchInt { ref discr, switch_ty, ref targets } => {
1166 self.codegen_switchint_terminator(helper, bx, discr, switch_ty, targets);
1169 mir::TerminatorKind::Return => {
1170 self.codegen_return_terminator(bx);
1173 mir::TerminatorKind::Unreachable => {
1177 mir::TerminatorKind::Drop { place, target, unwind } => {
1178 self.codegen_drop_terminator(helper, bx, place, target, unwind);
1181 mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
1182 self.codegen_assert_terminator(
1183 helper, bx, terminator, cond, expected, msg, target, cleanup,
1187 mir::TerminatorKind::DropAndReplace { .. } => {
1188 bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
1191 mir::TerminatorKind::Call {
1200 self.codegen_call_terminator(
1212 mir::TerminatorKind::GeneratorDrop | mir::TerminatorKind::Yield { .. } => {
1213 bug!("generator ops in codegen")
1215 mir::TerminatorKind::FalseEdge { .. } | mir::TerminatorKind::FalseUnwind { .. } => {
1216 bug!("borrowck false edges in codegen")
1219 mir::TerminatorKind::InlineAsm {
1227 self.codegen_asm_terminator(
1243 fn codegen_argument(
1246 op: OperandRef<'tcx, Bx::Value>,
1247 llargs: &mut Vec<Bx::Value>,
1248 arg: &ArgAbi<'tcx, Ty<'tcx>>,
1251 PassMode::Ignore => return,
1252 PassMode::Cast(_, true) => {
1253 // Fill padding with undef value, where applicable.
1254 llargs.push(bx.const_undef(bx.reg_backend_type(&Reg::i32())));
1256 PassMode::Pair(..) => match op.val {
1262 _ => bug!("codegen_argument: {:?} invalid for pair argument", op),
1264 PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => match op.val {
1265 Ref(a, Some(b), _) => {
1270 _ => bug!("codegen_argument: {:?} invalid for unsized indirect argument", op),
1275 // Force by-ref if we have to load through a cast pointer.
1276 let (mut llval, align, by_ref) = match op.val {
1277 Immediate(_) | Pair(..) => match arg.mode {
1278 PassMode::Indirect { .. } | PassMode::Cast(..) => {
1279 let scratch = PlaceRef::alloca(bx, arg.layout);
1280 op.val.store(bx, scratch);
1281 (scratch.llval, scratch.align, true)
1283 _ => (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false),
1285 Ref(llval, _, align) => {
1286 if arg.is_indirect() && align < arg.layout.align.abi {
1287 // `foo(packed.large_field)`. We can't pass the (unaligned) field directly. I
1288 // think that ATM (Rust 1.16) we only pass temporaries, but we shouldn't
1289 // have scary latent bugs around.
1291 let scratch = PlaceRef::alloca(bx, arg.layout);
1301 (scratch.llval, scratch.align, true)
1303 (llval, align, true)
1308 if by_ref && !arg.is_indirect() {
1309 // Have to load the argument, maybe while casting it.
1310 if let PassMode::Cast(ty, _) = &arg.mode {
1311 let llty = bx.cast_backend_type(ty);
1312 let addr = bx.pointercast(llval, bx.type_ptr_to(llty));
1313 llval = bx.load(llty, addr, align.min(arg.layout.align.abi));
1315 // We can't use `PlaceRef::load` here because the argument
1316 // may have a type we don't treat as immediate, but the ABI
1317 // used for this call is passing it by-value. In that case,
1318 // the load would just produce `OperandValue::Ref` instead
1319 // of the `OperandValue::Immediate` we need for the call.
1320 llval = bx.load(bx.backend_type(arg.layout), llval, align);
1321 if let abi::Abi::Scalar(scalar) = arg.layout.abi {
1322 if scalar.is_bool() {
1323 bx.range_metadata(llval, WrappingRange { start: 0, end: 1 });
1326 // We store bools as `i8` so we need to truncate to `i1`.
1327 llval = bx.to_immediate(llval, arg.layout);
1334 fn codegen_arguments_untupled(
1337 operand: &mir::Operand<'tcx>,
1338 llargs: &mut Vec<Bx::Value>,
1339 args: &[ArgAbi<'tcx, Ty<'tcx>>],
1341 let tuple = self.codegen_operand(bx, operand);
1343 // Handle both by-ref and immediate tuples.
1344 if let Ref(llval, None, align) = tuple.val {
1345 let tuple_ptr = PlaceRef::new_sized_aligned(llval, tuple.layout, align);
1346 for i in 0..tuple.layout.fields.count() {
1347 let field_ptr = tuple_ptr.project_field(bx, i);
1348 let field = bx.load_operand(field_ptr);
1349 self.codegen_argument(bx, field, llargs, &args[i]);
1351 } else if let Ref(_, Some(_), _) = tuple.val {
1352 bug!("closure arguments must be sized")
1354 // If the tuple is immediate, the elements are as well.
1355 for i in 0..tuple.layout.fields.count() {
1356 let op = tuple.extract_field(bx, i);
1357 self.codegen_argument(bx, op, llargs, &args[i]);
1360 tuple.layout.fields.count()
1363 fn get_caller_location(
1366 mut source_info: mir::SourceInfo,
1367 ) -> OperandRef<'tcx, Bx::Value> {
1370 let mut span_to_caller_location = |span: Span| {
1371 let topmost = span.ctxt().outer_expn().expansion_cause().unwrap_or(span);
1372 let caller = tcx.sess.source_map().lookup_char_pos(topmost.lo());
1373 let const_loc = tcx.const_caller_location((
1374 Symbol::intern(&caller.file.name.prefer_remapped().to_string_lossy()),
1376 caller.col_display as u32 + 1,
1378 OperandRef::from_const(bx, const_loc, bx.tcx().caller_location_ty())
1381 // Walk up the `SourceScope`s, in case some of them are from MIR inlining.
1382 // If so, the starting `source_info.span` is in the innermost inlined
1383 // function, and will be replaced with outer callsite spans as long
1384 // as the inlined functions were `#[track_caller]`.
1386 let scope_data = &self.mir.source_scopes[source_info.scope];
1388 if let Some((callee, callsite_span)) = scope_data.inlined {
1389 // Stop inside the most nested non-`#[track_caller]` function,
1390 // before ever reaching its caller (which is irrelevant).
1391 if !callee.def.requires_caller_location(tcx) {
1392 return span_to_caller_location(source_info.span);
1394 source_info.span = callsite_span;
1397 // Skip past all of the parents with `inlined: None`.
1398 match scope_data.inlined_parent_scope {
1399 Some(parent) => source_info.scope = parent,
1404 // No inlined `SourceScope`s, or all of them were `#[track_caller]`.
1405 self.caller_location.unwrap_or_else(|| span_to_caller_location(source_info.span))
1408 fn get_personality_slot(&mut self, bx: &mut Bx) -> PlaceRef<'tcx, Bx::Value> {
1410 if let Some(slot) = self.personality_slot {
1413 let layout = cx.layout_of(
1414 cx.tcx().intern_tup(&[cx.tcx().mk_mut_ptr(cx.tcx().types.u8), cx.tcx().types.i32]),
1416 let slot = PlaceRef::alloca(bx, layout);
1417 self.personality_slot = Some(slot);
1422 /// Returns the landing/cleanup pad wrapper around the given basic block.
1423 // FIXME(eddyb) rename this to `eh_pad_for`.
1424 fn landing_pad_for(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock {
1425 if let Some(landing_pad) = self.landing_pads[bb] {
1429 let landing_pad = self.landing_pad_for_uncached(bb);
1430 self.landing_pads[bb] = Some(landing_pad);
1434 // FIXME(eddyb) rename this to `eh_pad_for_uncached`.
1435 fn landing_pad_for_uncached(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock {
1436 let llbb = self.llbb(bb);
1437 if base::wants_msvc_seh(self.cx.sess()) {
1440 match self.mir[bb].terminator.as_ref().map(|t| &t.kind) {
1441 // This is a basic block that we're aborting the program for,
1442 // notably in an `extern` function. These basic blocks are inserted
1443 // so that we assert that `extern` functions do indeed not panic,
1444 // and if they do we abort the process.
1446 // On MSVC these are tricky though (where we're doing funclets). If
1447 // we were to do a cleanuppad (like below) the normal functions like
1448 // `longjmp` would trigger the abort logic, terminating the
1449 // program. Instead we insert the equivalent of `catch(...)` for C++
1450 // which magically doesn't trigger when `longjmp` files over this
1453 // Lots more discussion can be found on #48251 but this codegen is
1454 // modeled after clang's for:
1461 Some(&mir::TerminatorKind::Abort) => {
1463 Bx::append_block(self.cx, self.llfn, &format!("cs_funclet{:?}", bb));
1465 Bx::append_block(self.cx, self.llfn, &format!("cp_funclet{:?}", bb));
1468 let mut cs_bx = Bx::build(self.cx, cs_llbb);
1469 let cs = cs_bx.catch_switch(None, None, &[cp_llbb]);
1471 // The "null" here is actually a RTTI type descriptor for the
1472 // C++ personality function, but `catch (...)` has no type so
1473 // it's null. The 64 here is actually a bitfield which
1474 // represents that this is a catch-all block.
1475 let mut cp_bx = Bx::build(self.cx, cp_llbb);
1476 let null = cp_bx.const_null(
1477 cp_bx.type_i8p_ext(cp_bx.cx().data_layout().instruction_address_space),
1479 let sixty_four = cp_bx.const_i32(64);
1480 funclet = cp_bx.catch_pad(cs, &[null, sixty_four, null]);
1485 Bx::append_block(self.cx, self.llfn, &format!("funclet_{:?}", bb));
1486 ret_llbb = cleanup_llbb;
1487 let mut cleanup_bx = Bx::build(self.cx, cleanup_llbb);
1488 funclet = cleanup_bx.cleanup_pad(None, &[]);
1489 cleanup_bx.br(llbb);
1492 self.funclets[bb] = Some(funclet);
1495 let cleanup_llbb = Bx::append_block(self.cx, self.llfn, "cleanup");
1496 let mut cleanup_bx = Bx::build(self.cx, cleanup_llbb);
1498 let llpersonality = self.cx.eh_personality();
1499 let llretty = self.landing_pad_type();
1500 let lp = cleanup_bx.cleanup_landing_pad(llretty, llpersonality);
1502 let slot = self.get_personality_slot(&mut cleanup_bx);
1503 slot.storage_live(&mut cleanup_bx);
1504 Pair(cleanup_bx.extract_value(lp, 0), cleanup_bx.extract_value(lp, 1))
1505 .store(&mut cleanup_bx, slot);
1507 cleanup_bx.br(llbb);
1512 fn landing_pad_type(&self) -> Bx::Type {
1514 cx.type_struct(&[cx.type_i8p(), cx.type_i32()], false)
1517 fn unreachable_block(&mut self) -> Bx::BasicBlock {
1518 self.unreachable_block.unwrap_or_else(|| {
1519 let llbb = Bx::append_block(self.cx, self.llfn, "unreachable");
1520 let mut bx = Bx::build(self.cx, llbb);
1522 self.unreachable_block = Some(llbb);
1527 fn double_unwind_guard(&mut self) -> Bx::BasicBlock {
1528 self.double_unwind_guard.unwrap_or_else(|| {
1529 assert!(!base::wants_msvc_seh(self.cx.sess()));
1531 let llbb = Bx::append_block(self.cx, self.llfn, "abort");
1532 let mut bx = Bx::build(self.cx, llbb);
1533 self.set_debug_loc(&mut bx, mir::SourceInfo::outermost(self.mir.span));
1535 let llpersonality = self.cx.eh_personality();
1536 let llretty = self.landing_pad_type();
1537 bx.cleanup_landing_pad(llretty, llpersonality);
1539 let (fn_abi, fn_ptr) = common::build_langcall(&bx, None, LangItem::PanicNoUnwind);
1540 let fn_ty = bx.fn_decl_backend_type(&fn_abi);
1542 let llret = bx.call(fn_ty, Some(&fn_abi), fn_ptr, &[], None);
1543 bx.do_not_inline(llret);
1547 self.double_unwind_guard = Some(llbb);
1552 /// Get the backend `BasicBlock` for a MIR `BasicBlock`, either already
1553 /// cached in `self.cached_llbbs`, or created on demand (and cached).
1554 // FIXME(eddyb) rename `llbb` and other `ll`-prefixed things to use a
1555 // more backend-agnostic prefix such as `cg` (i.e. this would be `cgbb`).
1556 pub fn llbb(&mut self, bb: mir::BasicBlock) -> Bx::BasicBlock {
1557 self.cached_llbbs[bb].unwrap_or_else(|| {
1558 // FIXME(eddyb) only name the block if `fewer_names` is `false`.
1559 let llbb = Bx::append_block(self.cx, self.llfn, &format!("{:?}", bb));
1560 self.cached_llbbs[bb] = Some(llbb);
1565 fn make_return_dest(
1568 dest: mir::Place<'tcx>,
1569 fn_ret: &ArgAbi<'tcx, Ty<'tcx>>,
1570 llargs: &mut Vec<Bx::Value>,
1572 ) -> ReturnDest<'tcx, Bx::Value> {
1573 // If the return is ignored, we can just return a do-nothing `ReturnDest`.
1574 if fn_ret.is_ignore() {
1575 return ReturnDest::Nothing;
1577 let dest = if let Some(index) = dest.as_local() {
1578 match self.locals[index] {
1579 LocalRef::Place(dest) => dest,
1580 LocalRef::UnsizedPlace(_) => bug!("return type must be sized"),
1581 LocalRef::Operand(None) => {
1582 // Handle temporary places, specifically `Operand` ones, as
1583 // they don't have `alloca`s.
1584 return if fn_ret.is_indirect() {
1585 // Odd, but possible, case, we have an operand temporary,
1586 // but the calling convention has an indirect return.
1587 let tmp = PlaceRef::alloca(bx, fn_ret.layout);
1588 tmp.storage_live(bx);
1589 llargs.push(tmp.llval);
1590 ReturnDest::IndirectOperand(tmp, index)
1591 } else if is_intrinsic {
1592 // Currently, intrinsics always need a location to store
1593 // the result, so we create a temporary `alloca` for the
1595 let tmp = PlaceRef::alloca(bx, fn_ret.layout);
1596 tmp.storage_live(bx);
1597 ReturnDest::IndirectOperand(tmp, index)
1599 ReturnDest::DirectOperand(index)
1602 LocalRef::Operand(Some(_)) => {
1603 bug!("place local already assigned to");
1609 mir::PlaceRef { local: dest.local, projection: &dest.projection },
1612 if fn_ret.is_indirect() {
1613 if dest.align < dest.layout.align.abi {
1614 // Currently, MIR code generation does not create calls
1615 // that store directly to fields of packed structs (in
1616 // fact, the calls it creates write only to temps).
1618 // If someone changes that, please update this code path
1619 // to create a temporary.
1620 span_bug!(self.mir.span, "can't directly store to unaligned value");
1622 llargs.push(dest.llval);
1625 ReturnDest::Store(dest)
1629 fn codegen_transmute(&mut self, bx: &mut Bx, src: &mir::Operand<'tcx>, dst: mir::Place<'tcx>) {
1630 if let Some(index) = dst.as_local() {
1631 match self.locals[index] {
1632 LocalRef::Place(place) => self.codegen_transmute_into(bx, src, place),
1633 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
1634 LocalRef::Operand(None) => {
1635 let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst.as_ref()));
1636 assert!(!dst_layout.ty.has_erasable_regions());
1637 let place = PlaceRef::alloca(bx, dst_layout);
1638 place.storage_live(bx);
1639 self.codegen_transmute_into(bx, src, place);
1640 let op = bx.load_operand(place);
1641 place.storage_dead(bx);
1642 self.locals[index] = LocalRef::Operand(Some(op));
1643 self.debug_introduce_local(bx, index);
1645 LocalRef::Operand(Some(op)) => {
1646 assert!(op.layout.is_zst(), "assigning to initialized SSAtemp");
1650 let dst = self.codegen_place(bx, dst.as_ref());
1651 self.codegen_transmute_into(bx, src, dst);
1655 fn codegen_transmute_into(
1658 src: &mir::Operand<'tcx>,
1659 dst: PlaceRef<'tcx, Bx::Value>,
1661 let src = self.codegen_operand(bx, src);
1663 // Special-case transmutes between scalars as simple bitcasts.
1664 match (src.layout.abi, dst.layout.abi) {
1665 (abi::Abi::Scalar(src_scalar), abi::Abi::Scalar(dst_scalar)) => {
1666 // HACK(eddyb) LLVM doesn't like `bitcast`s between pointers and non-pointers.
1667 if (src_scalar.primitive() == abi::Pointer)
1668 == (dst_scalar.primitive() == abi::Pointer)
1670 assert_eq!(src.layout.size, dst.layout.size);
1672 // NOTE(eddyb) the `from_immediate` and `to_immediate_scalar`
1673 // conversions allow handling `bool`s the same as `u8`s.
1674 let src = bx.from_immediate(src.immediate());
1675 let src_as_dst = bx.bitcast(src, bx.backend_type(dst.layout));
1676 Immediate(bx.to_immediate_scalar(src_as_dst, dst_scalar)).store(bx, dst);
1683 let llty = bx.backend_type(src.layout);
1684 let cast_ptr = bx.pointercast(dst.llval, bx.type_ptr_to(llty));
1685 let align = src.layout.align.abi.min(dst.align);
1686 src.val.store(bx, PlaceRef::new_sized_aligned(cast_ptr, src.layout, align));
1689 // Stores the return value of a function call into it's final location.
1693 dest: ReturnDest<'tcx, Bx::Value>,
1694 ret_abi: &ArgAbi<'tcx, Ty<'tcx>>,
1697 use self::ReturnDest::*;
1701 Store(dst) => bx.store_arg(&ret_abi, llval, dst),
1702 IndirectOperand(tmp, index) => {
1703 let op = bx.load_operand(tmp);
1704 tmp.storage_dead(bx);
1705 self.locals[index] = LocalRef::Operand(Some(op));
1706 self.debug_introduce_local(bx, index);
1708 DirectOperand(index) => {
1709 // If there is a cast, we have to store and reload.
1710 let op = if let PassMode::Cast(..) = ret_abi.mode {
1711 let tmp = PlaceRef::alloca(bx, ret_abi.layout);
1712 tmp.storage_live(bx);
1713 bx.store_arg(&ret_abi, llval, tmp);
1714 let op = bx.load_operand(tmp);
1715 tmp.storage_dead(bx);
1718 OperandRef::from_immediate_or_packed_pair(bx, llval, ret_abi.layout)
1720 self.locals[index] = LocalRef::Operand(Some(op));
1721 self.debug_introduce_local(bx, index);
1727 enum ReturnDest<'tcx, V> {
1728 // Do nothing; the return value is indirect or ignored.
1730 // Store the return value to the pointer.
1731 Store(PlaceRef<'tcx, V>),
1732 // Store an indirect return value to an operand local place.
1733 IndirectOperand(PlaceRef<'tcx, V>, mir::Local),
1734 // Store a direct return value to an operand local place.
1735 DirectOperand(mir::Local),