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),
43 let inputs = fn_abi.args.iter().map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter()).flatten();
45 let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
46 // Sometimes the first param is an pointer to the place where the return value needs to be stored.
47 let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
49 Signature { params, returns, call_conv }
52 pub(crate) fn get_function_sig<'tcx>(
54 triple: &target_lexicon::Triple,
57 assert!(!inst.substs.needs_infer());
58 clif_sig_from_fn_abi(tcx, triple, &FnAbi::of_instance(&RevealAllLayoutCx(tcx), inst, &[]))
61 /// Instance must be monomorphized
62 pub(crate) fn import_function<'tcx>(
64 module: &mut dyn Module,
67 let name = tcx.symbol_name(inst).name.to_string();
68 let sig = get_function_sig(tcx, module.isa().triple(), inst);
69 module.declare_function(&name, Linkage::Import, &sig).unwrap()
72 impl<'tcx> FunctionCx<'_, '_, 'tcx> {
73 /// Instance must be monomorphized
74 pub(crate) fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
75 let func_id = import_function(self.tcx, self.cx.module, inst);
76 let func_ref = self.cx.module.declare_func_in_func(func_id, &mut self.bcx.func);
78 #[cfg(debug_assertions)]
79 self.add_comment(func_ref, format!("{:?}", inst));
84 pub(crate) fn lib_call(
87 params: Vec<AbiParam>,
88 returns: Vec<AbiParam>,
91 let sig = Signature { params, returns, call_conv: CallConv::triple_default(self.triple()) };
92 let func_id = self.cx.module.declare_function(&name, Linkage::Import, &sig).unwrap();
93 let func_ref = self.cx.module.declare_func_in_func(func_id, &mut self.bcx.func);
94 let call_inst = self.bcx.ins().call(func_ref, args);
95 #[cfg(debug_assertions)]
97 self.add_comment(call_inst, format!("easy_call {}", name));
99 let results = self.bcx.inst_results(call_inst);
100 assert!(results.len() <= 2, "{}", results.len());
104 pub(crate) fn easy_call(
107 args: &[CValue<'tcx>],
110 let (input_tys, args): (Vec<_>, Vec<_>) = args
113 (AbiParam::new(self.clif_type(arg.layout().ty).unwrap()), arg.load_scalar(self))
116 let return_layout = self.layout_of(return_ty);
117 let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
118 tup.types().map(|ty| AbiParam::new(self.clif_type(ty).unwrap())).collect()
120 vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
122 let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
124 [] => CValue::by_ref(
125 Pointer::const_addr(self, i64::from(self.pointer_type.bytes())),
128 [val] => CValue::by_val(val, return_layout),
129 [val, extra] => CValue::by_val_pair(val, extra, return_layout),
135 /// Make a [`CPlace`] capable of holding value of the specified type.
136 fn make_local_place<'tcx>(
137 fx: &mut FunctionCx<'_, '_, 'tcx>,
139 layout: TyAndLayout<'tcx>,
142 let place = if is_ssa {
143 if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi {
144 CPlace::new_var_pair(fx, local, layout)
146 CPlace::new_var(fx, local, layout)
149 CPlace::new_stack_slot(fx, layout)
152 #[cfg(debug_assertions)]
153 self::comments::add_local_place_comments(fx, place, local);
158 pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) {
159 fx.bcx.append_block_params_for_function_params(start_block);
161 fx.bcx.switch_to_block(start_block);
164 let ssa_analyzed = crate::analyze::analyze(fx);
166 #[cfg(debug_assertions)]
167 self::comments::add_args_header_comment(fx);
169 let mut block_params_iter = fx.bcx.func.dfg.block_params(start_block).to_vec().into_iter();
171 self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
172 assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
174 // None means pass_mode == NoPass
176 Normal(Option<CValue<'tcx>>),
177 Spread(Vec<Option<CValue<'tcx>>>),
180 let fn_abi = fx.fn_abi.take().unwrap();
181 let mut arg_abis_iter = fn_abi.args.iter();
187 let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty);
189 // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
190 if Some(local) == fx.mir.spread_arg {
191 // This argument (e.g. the last argument in the "rust-call" ABI)
192 // is a tuple that was spread at the ABI level and now we have
193 // to reconstruct it into a tuple local variable, from multiple
194 // individual function arguments.
196 let tupled_arg_tys = match arg_ty.kind() {
197 ty::Tuple(ref tys) => tys,
198 _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
201 let mut params = Vec::new();
202 for (i, _arg_ty) in tupled_arg_tys.types().enumerate() {
203 let arg_abi = arg_abis_iter.next().unwrap();
205 cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
209 (local, ArgKind::Spread(params), arg_ty)
211 let arg_abi = arg_abis_iter.next().unwrap();
213 cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
214 (local, ArgKind::Normal(param), arg_ty)
217 .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>();
219 assert!(fx.caller_location.is_none());
220 if fx.instance.def.requires_caller_location(fx.tcx) {
221 // Store caller location for `#[track_caller]`.
222 let arg_abi = arg_abis_iter.next().unwrap();
224 Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
227 assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
228 fx.fn_abi = Some(fn_abi);
229 assert!(block_params_iter.next().is_none(), "arg_value left behind");
231 #[cfg(debug_assertions)]
232 self::comments::add_locals_header_comment(fx);
234 for (local, arg_kind, ty) in func_params {
235 let layout = fx.layout_of(ty);
237 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
239 // While this is normally an optimization to prevent an unnecessary copy when an argument is
240 // not mutated by the current function, this is necessary to support unsized arguments.
241 if let ArgKind::Normal(Some(val)) = arg_kind {
242 if let Some((addr, meta)) = val.try_to_ptr() {
243 let local_decl = &fx.mir.local_decls[local];
244 // v this ! is important
245 let internally_mutable = !val
248 .is_freeze(fx.tcx.at(local_decl.source_info.span), ParamEnv::reveal_all());
249 if local_decl.mutability == mir::Mutability::Not && !internally_mutable {
250 // We wont mutate this argument, so it is fine to borrow the backing storage
251 // of this argument, to prevent a copy.
253 let place = if let Some(meta) = meta {
254 CPlace::for_ptr_with_extra(addr, meta, val.layout())
256 CPlace::for_ptr(addr, val.layout())
259 #[cfg(debug_assertions)]
260 self::comments::add_local_place_comments(fx, place, local);
262 assert_eq!(fx.local_map.push(place), local);
268 let place = make_local_place(fx, local, layout, is_ssa);
269 assert_eq!(fx.local_map.push(place), local);
272 ArgKind::Normal(param) => {
273 if let Some(param) = param {
274 place.write_cvalue(fx, param);
277 ArgKind::Spread(params) => {
278 for (i, param) in params.into_iter().enumerate() {
279 if let Some(param) = param {
280 place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param);
287 for local in fx.mir.vars_and_temps_iter() {
288 let ty = fx.monomorphize(fx.mir.local_decls[local].ty);
289 let layout = fx.layout_of(ty);
291 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
293 let place = make_local_place(fx, local, layout, is_ssa);
294 assert_eq!(fx.local_map.push(place), local);
297 fx.bcx.ins().jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]);
300 pub(crate) fn codegen_terminator_call<'tcx>(
301 fx: &mut FunctionCx<'_, '_, 'tcx>,
303 current_block: Block,
304 func: &Operand<'tcx>,
305 args: &[Operand<'tcx>],
306 destination: Option<(Place<'tcx>, BasicBlock)>,
308 let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
310 fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
312 let destination = destination.map(|(place, bb)| (codegen_place(fx, place), bb));
314 // Handle special calls like instrinsics and empty drop glue.
315 let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
316 let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
319 .polymorphize(fx.tcx);
321 if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
322 crate::intrinsics::codegen_llvm_intrinsic_call(
324 &fx.tcx.symbol_name(instance).name,
333 InstanceDef::Intrinsic(_) => {
334 crate::intrinsics::codegen_intrinsic_call(fx, instance, args, destination, span);
337 InstanceDef::DropGlue(_, None) => {
338 // empty drop glue - a nop.
339 let (_, dest) = destination.expect("Non terminating drop_in_place_real???");
340 let ret_block = fx.get_block(dest);
341 fx.bcx.ins().jump(ret_block, &[]);
350 let extra_args = &args[fn_sig.inputs().len()..];
351 let extra_args = extra_args
353 .map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx)))
354 .collect::<Vec<_>>();
355 let fn_abi = if let Some(instance) = instance {
356 FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), instance, &extra_args)
358 FnAbi::of_fn_ptr(&RevealAllLayoutCx(fx.tcx), fn_ty.fn_sig(fx.tcx), &extra_args)
361 let is_cold = instance
362 .map(|inst| fx.tcx.codegen_fn_attrs(inst.def_id()).flags.contains(CodegenFnAttrFlags::COLD))
365 fx.cold_blocks.insert(current_block);
368 // Unpack arguments tuple for closures
369 let args = if fn_sig.abi == Abi::RustCall {
370 assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
371 let self_arg = codegen_operand(fx, &args[0]);
372 let pack_arg = codegen_operand(fx, &args[1]);
374 let tupled_arguments = match pack_arg.layout().ty.kind() {
375 ty::Tuple(ref tupled_arguments) => tupled_arguments,
376 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
379 let mut args = Vec::with_capacity(1 + tupled_arguments.len());
381 for i in 0..tupled_arguments.len() {
382 args.push(pack_arg.value_field(fx, mir::Field::new(i)));
386 args.iter().map(|arg| codegen_operand(fx, arg)).collect::<Vec<_>>()
389 // | indirect call target
390 // | | the first argument to be passed
392 let (func_ref, first_arg) = match instance {
394 Some(Instance { def: InstanceDef::Virtual(_, idx), .. }) => {
395 #[cfg(debug_assertions)]
397 let nop_inst = fx.bcx.ins().nop();
400 format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0],),
403 let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0], idx);
404 (Some(method), smallvec![ptr])
411 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
412 .unwrap_or(smallvec![]),
417 #[cfg(debug_assertions)]
419 let nop_inst = fx.bcx.ins().nop();
420 fx.add_comment(nop_inst, "indirect call");
422 let func = codegen_operand(fx, func).load_scalar(fx);
426 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
427 .unwrap_or(smallvec![]),
432 let ret_place = destination.map(|(place, _)| place);
433 let (call_inst, call_args) = self::returning::codegen_with_call_return_arg(
438 let regular_args_count = args.len();
439 let mut call_args: Vec<Value> = return_ptr
441 .chain(first_arg.into_iter())
446 .map(|(i, arg)| adjust_arg_for_abi(fx, arg, &fn_abi.args[i]).into_iter())
449 .collect::<Vec<_>>();
451 if instance.map(|inst| inst.def.requires_caller_location(fx.tcx)).unwrap_or(false) {
452 // Pass the caller location for `#[track_caller]`.
453 let caller_location = fx.get_caller_location(span);
455 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[regular_args_count])
458 assert_eq!(fn_abi.args.len(), regular_args_count + 1);
460 assert_eq!(fn_abi.args.len(), regular_args_count);
463 let call_inst = if let Some(func_ref) = func_ref {
464 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
465 let sig = fx.bcx.import_signature(sig);
466 fx.bcx.ins().call_indirect(sig, func_ref, &call_args)
469 fx.get_function_ref(instance.expect("non-indirect call on non-FnDef type"));
470 fx.bcx.ins().call(func_ref, &call_args)
473 (call_inst, call_args)
477 // FIXME find a cleaner way to support varargs
478 if fn_sig.c_variadic {
479 if fn_sig.abi != Abi::C {
480 fx.tcx.sess.span_fatal(span, &format!("Variadic call for non-C abi {:?}", fn_sig.abi));
482 let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap();
483 let abi_params = call_args
486 let ty = fx.bcx.func.dfg.value_type(arg);
488 // FIXME set %al to upperbound on float args once floats are supported
489 fx.tcx.sess.span_fatal(span, &format!("Non int ty {:?} for variadic call", ty));
493 .collect::<Vec<AbiParam>>();
494 fx.bcx.func.dfg.signatures[sig_ref].params = abi_params;
497 if let Some((_, dest)) = destination {
498 let ret_block = fx.get_block(dest);
499 fx.bcx.ins().jump(ret_block, &[]);
501 trap_unreachable(fx, "[corruption] Diverging function returned");
505 pub(crate) fn codegen_drop<'tcx>(
506 fx: &mut FunctionCx<'_, '_, 'tcx>,
508 drop_place: CPlace<'tcx>,
510 let ty = drop_place.layout().ty;
511 let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
513 if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
514 // we don't actually need to drop anything
518 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
519 let ptr = ptr.get_addr(fx);
520 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
522 // FIXME(eddyb) perhaps move some of this logic into
523 // `Instance::resolve_drop_in_place`?
524 let virtual_drop = Instance {
525 def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
526 substs: drop_instance.substs,
528 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), virtual_drop, &[]);
530 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
531 let sig = fx.bcx.import_signature(sig);
532 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
535 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
537 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), drop_instance, &[]);
539 let arg_value = drop_place.place_ref(
541 fx.layout_of(fx.tcx.mk_ref(
542 &ty::RegionKind::ReErased,
543 TypeAndMut { ty, mutbl: crate::rustc_hir::Mutability::Mut },
546 let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0]);
548 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
550 if drop_instance.def.requires_caller_location(fx.tcx) {
551 // Pass the caller location for `#[track_caller]`.
552 let caller_location = fx.get_caller_location(span);
554 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1]).into_iter(),
558 let func_ref = fx.get_function_ref(drop_instance);
559 fx.bcx.ins().call(func_ref, &call_args);