1 //! Handling of everything related to the calling convention. Also fills `fx.local_map`.
3 #[cfg(debug_assertions)]
8 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
9 use rustc_middle::ty::layout::FnAbiExt;
10 use rustc_target::abi::call::{Conv, FnAbi};
11 use rustc_target::spec::abi::Abi;
13 use cranelift_codegen::ir::AbiParam;
14 use smallvec::smallvec;
16 use self::pass_mode::*;
17 use crate::prelude::*;
19 pub(crate) use self::returning::{can_return_to_ssa_var, codegen_return};
21 fn clif_sig_from_fn_abi<'tcx>(
23 triple: &target_lexicon::Triple,
24 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
26 let call_conv = match fn_abi.conv {
27 Conv::Rust | Conv::C => CallConv::triple_default(triple),
28 Conv::X86_64SysV => CallConv::SystemV,
29 Conv::X86_64Win64 => CallConv::WindowsFastcall,
31 | Conv::CCmseNonSecureCall
41 | Conv::AvrNonBlockingInterrupt => todo!("{:?}", fn_abi.conv),
46 .map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter())
49 let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
50 // Sometimes the first param is an pointer to the place where the return value needs to be stored.
51 let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
60 pub(crate) fn get_function_sig<'tcx>(
62 triple: &target_lexicon::Triple,
65 assert!(!inst.substs.needs_infer());
69 &FnAbi::of_instance(&RevealAllLayoutCx(tcx), inst, &[]),
73 /// Instance must be monomorphized
74 pub(crate) fn import_function<'tcx>(
76 module: &mut dyn Module,
79 let name = tcx.symbol_name(inst).name.to_string();
80 let sig = get_function_sig(tcx, module.isa().triple(), inst);
82 .declare_function(&name, Linkage::Import, &sig)
86 impl<'tcx> FunctionCx<'_, '_, 'tcx> {
87 /// Instance must be monomorphized
88 pub(crate) fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
89 let func_id = import_function(self.tcx, self.cx.module, inst);
93 .declare_func_in_func(func_id, &mut self.bcx.func);
95 #[cfg(debug_assertions)]
96 self.add_comment(func_ref, format!("{:?}", inst));
101 pub(crate) fn lib_call(
104 params: Vec<AbiParam>,
105 returns: Vec<AbiParam>,
108 let sig = Signature {
111 call_conv: CallConv::triple_default(self.triple()),
116 .declare_function(&name, Linkage::Import, &sig)
121 .declare_func_in_func(func_id, &mut self.bcx.func);
122 let call_inst = self.bcx.ins().call(func_ref, args);
123 #[cfg(debug_assertions)]
125 self.add_comment(call_inst, format!("easy_call {}", name));
127 let results = self.bcx.inst_results(call_inst);
128 assert!(results.len() <= 2, "{}", results.len());
132 pub(crate) fn easy_call(
135 args: &[CValue<'tcx>],
138 let (input_tys, args): (Vec<_>, Vec<_>) = args
142 AbiParam::new(self.clif_type(arg.layout().ty).unwrap()),
143 arg.load_scalar(self),
147 let return_layout = self.layout_of(return_ty);
148 let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
150 .map(|ty| AbiParam::new(self.clif_type(ty).unwrap()))
153 vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
155 let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
157 [] => CValue::by_ref(
158 Pointer::const_addr(self, i64::from(self.pointer_type.bytes())),
161 [val] => CValue::by_val(val, return_layout),
162 [val, extra] => CValue::by_val_pair(val, extra, return_layout),
168 /// Make a [`CPlace`] capable of holding value of the specified type.
169 fn make_local_place<'tcx>(
170 fx: &mut FunctionCx<'_, '_, 'tcx>,
172 layout: TyAndLayout<'tcx>,
175 let place = if is_ssa {
176 if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi {
177 CPlace::new_var_pair(fx, local, layout)
179 CPlace::new_var(fx, local, layout)
182 CPlace::new_stack_slot(fx, layout)
185 #[cfg(debug_assertions)]
186 self::comments::add_local_place_comments(fx, place, local);
191 pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) {
192 fx.bcx.append_block_params_for_function_params(start_block);
194 fx.bcx.switch_to_block(start_block);
197 let ssa_analyzed = crate::analyze::analyze(fx);
199 #[cfg(debug_assertions)]
200 self::comments::add_args_header_comment(fx);
202 let mut block_params_iter = fx
206 .block_params(start_block)
210 self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
211 assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
213 // None means pass_mode == NoPass
215 Normal(Option<CValue<'tcx>>),
216 Spread(Vec<Option<CValue<'tcx>>>),
219 let fn_abi = fx.fn_abi.take().unwrap();
220 let mut arg_abis_iter = fn_abi.args.iter();
226 let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty);
228 // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
229 if Some(local) == fx.mir.spread_arg {
230 // This argument (e.g. the last argument in the "rust-call" ABI)
231 // is a tuple that was spread at the ABI level and now we have
232 // to reconstruct it into a tuple local variable, from multiple
233 // individual function arguments.
235 let tupled_arg_tys = match arg_ty.kind() {
236 ty::Tuple(ref tys) => tys,
237 _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
240 let mut params = Vec::new();
241 for (i, _arg_ty) in tupled_arg_tys.types().enumerate() {
242 let arg_abi = arg_abis_iter.next().unwrap();
244 cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
248 (local, ArgKind::Spread(params), arg_ty)
250 let arg_abi = arg_abis_iter.next().unwrap();
252 cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
253 (local, ArgKind::Normal(param), arg_ty)
256 .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>();
258 assert!(fx.caller_location.is_none());
259 if fx.instance.def.requires_caller_location(fx.tcx) {
260 // Store caller location for `#[track_caller]`.
261 let arg_abi = arg_abis_iter.next().unwrap();
263 Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
266 assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
267 fx.fn_abi = Some(fn_abi);
268 assert!(block_params_iter.next().is_none(), "arg_value left behind");
270 #[cfg(debug_assertions)]
271 self::comments::add_locals_header_comment(fx);
273 for (local, arg_kind, ty) in func_params {
274 let layout = fx.layout_of(ty);
276 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
278 // While this is normally an optimization to prevent an unnecessary copy when an argument is
279 // not mutated by the current function, this is necessary to support unsized arguments.
280 if let ArgKind::Normal(Some(val)) = arg_kind {
281 if let Some((addr, meta)) = val.try_to_ptr() {
282 let local_decl = &fx.mir.local_decls[local];
283 // v this ! is important
284 let internally_mutable = !val.layout().ty.is_freeze(
285 fx.tcx.at(local_decl.source_info.span),
286 ParamEnv::reveal_all(),
288 if local_decl.mutability == mir::Mutability::Not && !internally_mutable {
289 // We wont mutate this argument, so it is fine to borrow the backing storage
290 // of this argument, to prevent a copy.
292 let place = if let Some(meta) = meta {
293 CPlace::for_ptr_with_extra(addr, meta, val.layout())
295 CPlace::for_ptr(addr, val.layout())
298 #[cfg(debug_assertions)]
299 self::comments::add_local_place_comments(fx, place, local);
301 assert_eq!(fx.local_map.push(place), local);
307 let place = make_local_place(fx, local, layout, is_ssa);
308 assert_eq!(fx.local_map.push(place), local);
311 ArgKind::Normal(param) => {
312 if let Some(param) = param {
313 place.write_cvalue(fx, param);
316 ArgKind::Spread(params) => {
317 for (i, param) in params.into_iter().enumerate() {
318 if let Some(param) = param {
320 .place_field(fx, mir::Field::new(i))
321 .write_cvalue(fx, param);
328 for local in fx.mir.vars_and_temps_iter() {
329 let ty = fx.monomorphize(fx.mir.local_decls[local].ty);
330 let layout = fx.layout_of(ty);
332 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
334 let place = make_local_place(fx, local, layout, is_ssa);
335 assert_eq!(fx.local_map.push(place), local);
340 .jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]);
343 pub(crate) fn codegen_terminator_call<'tcx>(
344 fx: &mut FunctionCx<'_, '_, 'tcx>,
346 current_block: Block,
347 func: &Operand<'tcx>,
348 args: &[Operand<'tcx>],
349 destination: Option<(Place<'tcx>, BasicBlock)>,
351 let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
354 .normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
356 let destination = destination.map(|(place, bb)| (codegen_place(fx, place), bb));
358 // Handle special calls like instrinsics and empty drop glue.
359 let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
360 let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
363 .polymorphize(fx.tcx);
365 if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
366 crate::intrinsics::codegen_llvm_intrinsic_call(
368 &fx.tcx.symbol_name(instance).name,
377 InstanceDef::Intrinsic(_) => {
378 crate::intrinsics::codegen_intrinsic_call(fx, instance, args, destination, span);
381 InstanceDef::DropGlue(_, None) => {
382 // empty drop glue - a nop.
383 let (_, dest) = destination.expect("Non terminating drop_in_place_real???");
384 let ret_block = fx.get_block(dest);
385 fx.bcx.ins().jump(ret_block, &[]);
394 let extra_args = &args[fn_sig.inputs().len()..];
395 let extra_args = extra_args
397 .map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx)))
398 .collect::<Vec<_>>();
399 let fn_abi = if let Some(instance) = instance {
400 FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), instance, &extra_args)
403 &RevealAllLayoutCx(fx.tcx),
404 fn_ty.fn_sig(fx.tcx),
409 let is_cold = instance
412 .codegen_fn_attrs(inst.def_id())
414 .contains(CodegenFnAttrFlags::COLD)
418 fx.cold_blocks.insert(current_block);
421 // Unpack arguments tuple for closures
422 let args = if fn_sig.abi == Abi::RustCall {
423 assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
424 let self_arg = codegen_operand(fx, &args[0]);
425 let pack_arg = codegen_operand(fx, &args[1]);
427 let tupled_arguments = match pack_arg.layout().ty.kind() {
428 ty::Tuple(ref tupled_arguments) => tupled_arguments,
429 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
432 let mut args = Vec::with_capacity(1 + tupled_arguments.len());
434 for i in 0..tupled_arguments.len() {
435 args.push(pack_arg.value_field(fx, mir::Field::new(i)));
440 .map(|arg| codegen_operand(fx, arg))
444 // | indirect call target
445 // | | the first argument to be passed
447 let (func_ref, first_arg) = match instance {
450 def: InstanceDef::Virtual(_, idx),
453 #[cfg(debug_assertions)]
455 let nop_inst = fx.bcx.ins().nop();
458 format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0],),
461 let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0], idx);
462 (Some(method), smallvec![ptr])
469 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
470 .unwrap_or(smallvec![]),
475 #[cfg(debug_assertions)]
477 let nop_inst = fx.bcx.ins().nop();
478 fx.add_comment(nop_inst, "indirect call");
480 let func = codegen_operand(fx, func).load_scalar(fx);
484 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
485 .unwrap_or(smallvec![]),
490 let ret_place = destination.map(|(place, _)| place);
491 let (call_inst, call_args) = self::returning::codegen_with_call_return_arg(
496 let regular_args_count = args.len();
497 let mut call_args: Vec<Value> = return_ptr
499 .chain(first_arg.into_iter())
504 .map(|(i, arg)| adjust_arg_for_abi(fx, arg, &fn_abi.args[i]).into_iter())
507 .collect::<Vec<_>>();
510 .map(|inst| inst.def.requires_caller_location(fx.tcx))
513 // Pass the caller location for `#[track_caller]`.
514 let caller_location = fx.get_caller_location(span);
516 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[regular_args_count])
519 assert_eq!(fn_abi.args.len(), regular_args_count + 1);
521 assert_eq!(fn_abi.args.len(), regular_args_count);
524 let call_inst = if let Some(func_ref) = func_ref {
525 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
526 let sig = fx.bcx.import_signature(sig);
527 fx.bcx.ins().call_indirect(sig, func_ref, &call_args)
530 fx.get_function_ref(instance.expect("non-indirect call on non-FnDef type"));
531 fx.bcx.ins().call(func_ref, &call_args)
534 (call_inst, call_args)
538 // FIXME find a cleaner way to support varargs
539 if fn_sig.c_variadic {
540 if fn_sig.abi != Abi::C {
541 fx.tcx.sess.span_fatal(
543 &format!("Variadic call for non-C abi {:?}", fn_sig.abi),
546 let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap();
547 let abi_params = call_args
550 let ty = fx.bcx.func.dfg.value_type(arg);
552 // FIXME set %al to upperbound on float args once floats are supported
555 .span_fatal(span, &format!("Non int ty {:?} for variadic call", ty));
559 .collect::<Vec<AbiParam>>();
560 fx.bcx.func.dfg.signatures[sig_ref].params = abi_params;
563 if let Some((_, dest)) = destination {
564 let ret_block = fx.get_block(dest);
565 fx.bcx.ins().jump(ret_block, &[]);
567 trap_unreachable(fx, "[corruption] Diverging function returned");
571 pub(crate) fn codegen_drop<'tcx>(
572 fx: &mut FunctionCx<'_, '_, 'tcx>,
574 drop_place: CPlace<'tcx>,
576 let ty = drop_place.layout().ty;
577 let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
579 if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
580 // we don't actually need to drop anything
584 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
585 let ptr = ptr.get_addr(fx);
586 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
588 // FIXME(eddyb) perhaps move some of this logic into
589 // `Instance::resolve_drop_in_place`?
590 let virtual_drop = Instance {
591 def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
592 substs: drop_instance.substs,
594 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), virtual_drop, &[]);
596 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
597 let sig = fx.bcx.import_signature(sig);
598 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
601 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
603 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), drop_instance, &[]);
605 let arg_value = drop_place.place_ref(
607 fx.layout_of(fx.tcx.mk_ref(
608 &ty::RegionKind::ReErased,
611 mutbl: crate::rustc_hir::Mutability::Mut,
615 let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0]);
617 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
619 if drop_instance.def.requires_caller_location(fx.tcx) {
620 // Pass the caller location for `#[track_caller]`.
621 let caller_location = fx.get_caller_location(span);
623 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1]).into_iter(),
627 let func_ref = fx.get_function_ref(drop_instance);
628 fx.bcx.ins().call(func_ref, &call_args);