1 //! Handling of everything related to the calling convention. Also fills `fx.local_map`.
7 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
8 use rustc_middle::ty::layout::FnAbiOf;
9 use rustc_target::abi::call::{Conv, FnAbi};
10 use rustc_target::spec::abi::Abi;
12 use cranelift_codegen::ir::{AbiParam, SigRef};
14 use self::pass_mode::*;
15 use crate::prelude::*;
17 pub(crate) use self::returning::codegen_return;
19 fn clif_sig_from_fn_abi<'tcx>(
21 default_call_conv: CallConv,
22 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
24 let call_conv = match fn_abi.conv {
25 Conv::Rust | Conv::C => default_call_conv,
26 Conv::X86_64SysV => CallConv::SystemV,
27 Conv::X86_64Win64 => CallConv::WindowsFastcall,
29 | Conv::CCmseNonSecureCall
39 | Conv::AvrNonBlockingInterrupt => todo!("{:?}", fn_abi.conv),
41 let inputs = fn_abi.args.iter().map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter()).flatten();
43 let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
44 // Sometimes the first param is an pointer to the place where the return value needs to be stored.
45 let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
47 Signature { params, returns, call_conv }
50 pub(crate) fn get_function_sig<'tcx>(
52 triple: &target_lexicon::Triple,
55 assert!(!inst.substs.needs_infer());
58 CallConv::triple_default(triple),
59 &RevealAllLayoutCx(tcx).fn_abi_of_instance(inst, ty::List::empty()),
63 /// Instance must be monomorphized
64 pub(crate) fn import_function<'tcx>(
66 module: &mut dyn Module,
69 let name = tcx.symbol_name(inst).name;
70 let sig = get_function_sig(tcx, module.isa().triple(), inst);
71 module.declare_function(name, Linkage::Import, &sig).unwrap()
74 impl<'tcx> FunctionCx<'_, '_, 'tcx> {
75 /// Instance must be monomorphized
76 pub(crate) fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
77 let func_id = import_function(self.tcx, self.module, inst);
78 let func_ref = self.module.declare_func_in_func(func_id, &mut self.bcx.func);
80 if self.clif_comments.enabled() {
81 self.add_comment(func_ref, format!("{:?}", inst));
87 pub(crate) fn lib_call(
90 params: Vec<AbiParam>,
91 returns: Vec<AbiParam>,
94 let sig = Signature { params, returns, call_conv: self.target_config.default_call_conv };
95 let func_id = self.module.declare_function(name, Linkage::Import, &sig).unwrap();
96 let func_ref = self.module.declare_func_in_func(func_id, &mut self.bcx.func);
97 if self.clif_comments.enabled() {
98 self.add_comment(func_ref, format!("{:?}", name));
100 let call_inst = self.bcx.ins().call(func_ref, args);
101 if self.clif_comments.enabled() {
102 self.add_comment(call_inst, format!("easy_call {}", name));
104 let results = self.bcx.inst_results(call_inst);
105 assert!(results.len() <= 2, "{}", results.len());
109 pub(crate) fn easy_call(
112 args: &[CValue<'tcx>],
115 let (input_tys, args): (Vec<_>, Vec<_>) = args
118 (AbiParam::new(self.clif_type(arg.layout().ty).unwrap()), arg.load_scalar(self))
121 let return_layout = self.layout_of(return_ty);
122 let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
123 tup.iter().map(|ty| AbiParam::new(self.clif_type(ty).unwrap())).collect()
125 vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
127 let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
129 [] => CValue::by_ref(
130 Pointer::const_addr(self, i64::from(self.pointer_type.bytes())),
133 [val] => CValue::by_val(val, return_layout),
134 [val, extra] => CValue::by_val_pair(val, extra, return_layout),
140 /// Make a [`CPlace`] capable of holding value of the specified type.
141 fn make_local_place<'tcx>(
142 fx: &mut FunctionCx<'_, '_, 'tcx>,
144 layout: TyAndLayout<'tcx>,
147 let place = if is_ssa {
148 if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi {
149 CPlace::new_var_pair(fx, local, layout)
151 CPlace::new_var(fx, local, layout)
154 CPlace::new_stack_slot(fx, layout)
157 self::comments::add_local_place_comments(fx, place, local);
162 pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) {
163 fx.bcx.append_block_params_for_function_params(start_block);
165 fx.bcx.switch_to_block(start_block);
168 let ssa_analyzed = crate::analyze::analyze(fx);
170 self::comments::add_args_header_comment(fx);
172 let mut block_params_iter = fx.bcx.func.dfg.block_params(start_block).to_vec().into_iter();
174 self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
175 assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
177 // None means pass_mode == NoPass
179 Normal(Option<CValue<'tcx>>),
180 Spread(Vec<Option<CValue<'tcx>>>),
183 let fn_abi = fx.fn_abi.take().unwrap();
184 let mut arg_abis_iter = fn_abi.args.iter();
190 let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty);
192 // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
193 if Some(local) == fx.mir.spread_arg {
194 // This argument (e.g. the last argument in the "rust-call" ABI)
195 // is a tuple that was spread at the ABI level and now we have
196 // to reconstruct it into a tuple local variable, from multiple
197 // individual function arguments.
199 let tupled_arg_tys = match arg_ty.kind() {
200 ty::Tuple(ref tys) => tys,
201 _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
204 let mut params = Vec::new();
205 for (i, _arg_ty) in tupled_arg_tys.iter().enumerate() {
206 let arg_abi = arg_abis_iter.next().unwrap();
208 cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
212 (local, ArgKind::Spread(params), arg_ty)
214 let arg_abi = arg_abis_iter.next().unwrap();
216 cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
217 (local, ArgKind::Normal(param), arg_ty)
220 .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>();
222 assert!(fx.caller_location.is_none());
223 if fx.instance.def.requires_caller_location(fx.tcx) {
224 // Store caller location for `#[track_caller]`.
225 let arg_abi = arg_abis_iter.next().unwrap();
227 Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
230 assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
231 fx.fn_abi = Some(fn_abi);
232 assert!(block_params_iter.next().is_none(), "arg_value left behind");
234 self::comments::add_locals_header_comment(fx);
236 for (local, arg_kind, ty) in func_params {
237 let layout = fx.layout_of(ty);
239 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
241 // While this is normally an optimization to prevent an unnecessary copy when an argument is
242 // not mutated by the current function, this is necessary to support unsized arguments.
243 if let ArgKind::Normal(Some(val)) = arg_kind {
244 if let Some((addr, meta)) = val.try_to_ptr() {
245 // Ownership of the value at the backing storage for an argument is passed to the
246 // callee per the ABI, so it is fine to borrow the backing storage of this argument
247 // to prevent a copy.
249 let place = if let Some(meta) = meta {
250 CPlace::for_ptr_with_extra(addr, meta, val.layout())
252 CPlace::for_ptr(addr, val.layout())
255 self::comments::add_local_place_comments(fx, place, local);
257 assert_eq!(fx.local_map.push(place), local);
262 let place = make_local_place(fx, local, layout, is_ssa);
263 assert_eq!(fx.local_map.push(place), local);
266 ArgKind::Normal(param) => {
267 if let Some(param) = param {
268 place.write_cvalue(fx, param);
271 ArgKind::Spread(params) => {
272 for (i, param) in params.into_iter().enumerate() {
273 if let Some(param) = param {
274 place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param);
281 for local in fx.mir.vars_and_temps_iter() {
282 let ty = fx.monomorphize(fx.mir.local_decls[local].ty);
283 let layout = fx.layout_of(ty);
285 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
287 let place = make_local_place(fx, local, layout, is_ssa);
288 assert_eq!(fx.local_map.push(place), local);
291 fx.bcx.ins().jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]);
294 struct CallArgument<'tcx> {
299 // FIXME avoid intermediate `CValue` before calling `adjust_arg_for_abi`
300 fn codegen_call_argument_operand<'tcx>(
301 fx: &mut FunctionCx<'_, '_, 'tcx>,
302 operand: &Operand<'tcx>,
303 ) -> CallArgument<'tcx> {
305 value: codegen_operand(fx, operand),
306 is_owned: matches!(operand, Operand::Move(_)),
310 pub(crate) fn codegen_terminator_call<'tcx>(
311 fx: &mut FunctionCx<'_, '_, 'tcx>,
313 func: &Operand<'tcx>,
314 args: &[Operand<'tcx>],
315 mir_dest: Option<(Place<'tcx>, BasicBlock)>,
317 let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
319 fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
321 let destination = mir_dest.map(|(place, bb)| (codegen_place(fx, place), bb));
323 // Handle special calls like instrinsics and empty drop glue.
324 let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
325 let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
328 .polymorphize(fx.tcx);
330 if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
331 crate::intrinsics::codegen_llvm_intrinsic_call(
333 &fx.tcx.symbol_name(instance).name,
342 InstanceDef::Intrinsic(_) => {
343 crate::intrinsics::codegen_intrinsic_call(fx, instance, args, destination, span);
346 InstanceDef::DropGlue(_, None) => {
347 // empty drop glue - a nop.
348 let (_, dest) = destination.expect("Non terminating drop_in_place_real???");
349 let ret_block = fx.get_block(dest);
350 fx.bcx.ins().jump(ret_block, &[]);
359 let extra_args = &args[fn_sig.inputs().len()..];
362 .mk_type_list(extra_args.iter().map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx))));
363 let fn_abi = if let Some(instance) = instance {
364 RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(instance, extra_args)
366 RevealAllLayoutCx(fx.tcx).fn_abi_of_fn_ptr(fn_ty.fn_sig(fx.tcx), extra_args)
369 let is_cold = instance
370 .map(|inst| fx.tcx.codegen_fn_attrs(inst.def_id()).flags.contains(CodegenFnAttrFlags::COLD))
373 fx.bcx.set_cold_block(fx.bcx.current_block().unwrap());
374 if let Some((_place, destination_block)) = destination {
375 fx.bcx.set_cold_block(fx.get_block(destination_block));
379 // Unpack arguments tuple for closures
380 let mut args = if fn_sig.abi == Abi::RustCall {
381 assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
382 let self_arg = codegen_call_argument_operand(fx, &args[0]);
383 let pack_arg = codegen_call_argument_operand(fx, &args[1]);
385 let tupled_arguments = match pack_arg.value.layout().ty.kind() {
386 ty::Tuple(ref tupled_arguments) => tupled_arguments,
387 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
390 let mut args = Vec::with_capacity(1 + tupled_arguments.len());
392 for i in 0..tupled_arguments.len() {
393 args.push(CallArgument {
394 value: pack_arg.value.value_field(fx, mir::Field::new(i)),
395 is_owned: pack_arg.is_owned,
400 args.iter().map(|arg| codegen_call_argument_operand(fx, arg)).collect::<Vec<_>>()
403 // Pass the caller location for `#[track_caller]`.
404 if instance.map(|inst| inst.def.requires_caller_location(fx.tcx)).unwrap_or(false) {
405 let caller_location = fx.get_caller_location(span);
406 args.push(CallArgument { value: caller_location, is_owned: false });
410 assert_eq!(fn_abi.args.len(), args.len());
414 Indirect(SigRef, Value),
417 let (func_ref, first_arg_override) = match instance {
419 Some(Instance { def: InstanceDef::Virtual(_, idx), .. }) => {
420 if fx.clif_comments.enabled() {
421 let nop_inst = fx.bcx.ins().nop();
424 format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0]),
428 let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0].value, idx);
429 let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi);
430 let sig = fx.bcx.import_signature(sig);
432 (CallTarget::Indirect(sig, method), Some(ptr))
437 let func_ref = fx.get_function_ref(instance);
438 (CallTarget::Direct(func_ref), None)
443 if fx.clif_comments.enabled() {
444 let nop_inst = fx.bcx.ins().nop();
445 fx.add_comment(nop_inst, "indirect call");
448 let func = codegen_operand(fx, func).load_scalar(fx);
449 let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi);
450 let sig = fx.bcx.import_signature(sig);
452 (CallTarget::Indirect(sig, func), None)
456 let ret_place = destination.map(|(place, _)| place);
457 self::returning::codegen_with_call_return_arg(fx, &fn_abi.ret, ret_place, |fx, return_ptr| {
458 let call_args = return_ptr
460 .chain(first_arg_override.into_iter())
464 .skip(if first_arg_override.is_some() { 1 } else { 0 })
466 adjust_arg_for_abi(fx, arg.value, &fn_abi.args[i], arg.is_owned).into_iter()
470 .collect::<Vec<Value>>();
472 let call_inst = match func_ref {
473 CallTarget::Direct(func_ref) => fx.bcx.ins().call(func_ref, &call_args),
474 CallTarget::Indirect(sig, func_ptr) => {
475 fx.bcx.ins().call_indirect(sig, func_ptr, &call_args)
479 // FIXME find a cleaner way to support varargs
480 if fn_sig.c_variadic {
481 if !matches!(fn_sig.abi, Abi::C { .. }) {
484 .span_fatal(span, &format!("Variadic call for non-C abi {:?}", fn_sig.abi));
486 let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap();
487 let abi_params = call_args
490 let ty = fx.bcx.func.dfg.value_type(arg);
492 // FIXME set %al to upperbound on float args once floats are supported
495 .span_fatal(span, &format!("Non int ty {:?} for variadic call", ty));
499 .collect::<Vec<AbiParam>>();
500 fx.bcx.func.dfg.signatures[sig_ref].params = abi_params;
506 if let Some((_, dest)) = destination {
507 let ret_block = fx.get_block(dest);
508 fx.bcx.ins().jump(ret_block, &[]);
510 fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
514 pub(crate) fn codegen_drop<'tcx>(
515 fx: &mut FunctionCx<'_, '_, 'tcx>,
517 drop_place: CPlace<'tcx>,
519 let ty = drop_place.layout().ty;
520 let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
522 if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
523 // we don't actually need to drop anything
527 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
528 let ptr = ptr.get_addr(fx);
529 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
531 // FIXME(eddyb) perhaps move some of this logic into
532 // `Instance::resolve_drop_in_place`?
533 let virtual_drop = Instance {
534 def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
535 substs: drop_instance.substs,
538 RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(virtual_drop, ty::List::empty());
540 let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi);
541 let sig = fx.bcx.import_signature(sig);
542 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
545 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
548 RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(drop_instance, ty::List::empty());
550 let arg_value = drop_place.place_ref(
552 fx.layout_of(fx.tcx.mk_ref(
553 fx.tcx.lifetimes.re_erased,
554 TypeAndMut { ty, mutbl: crate::rustc_hir::Mutability::Mut },
557 let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0], true);
559 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
561 if drop_instance.def.requires_caller_location(fx.tcx) {
562 // Pass the caller location for `#[track_caller]`.
563 let caller_location = fx.get_caller_location(span);
565 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1], false).into_iter(),
569 let func_ref = fx.get_function_ref(drop_instance);
570 fx.bcx.ins().call(func_ref, &call_args);