1 //! Handling of everything related to the calling convention. Also fills `fx.local_map`.
7 use cranelift_module::ModuleError;
8 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
9 use rustc_middle::ty::layout::FnAbiOf;
10 use rustc_target::abi::call::{Conv, FnAbi};
11 use rustc_target::spec::abi::Abi;
13 use cranelift_codegen::ir::{AbiParam, SigRef};
15 use self::pass_mode::*;
16 use crate::prelude::*;
18 pub(crate) use self::returning::codegen_return;
20 fn clif_sig_from_fn_abi<'tcx>(
22 default_call_conv: CallConv,
23 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
25 let call_conv = match fn_abi.conv {
26 Conv::Rust | Conv::C => default_call_conv,
27 Conv::RustCold => CallConv::Cold,
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());
60 CallConv::triple_default(triple),
61 &RevealAllLayoutCx(tcx).fn_abi_of_instance(inst, ty::List::empty()),
65 /// Instance must be monomorphized
66 pub(crate) fn import_function<'tcx>(
68 module: &mut dyn Module,
71 let name = tcx.symbol_name(inst).name;
72 let sig = get_function_sig(tcx, module.isa().triple(), inst);
73 match module.declare_function(name, Linkage::Import, &sig) {
74 Ok(func_id) => func_id,
75 Err(ModuleError::IncompatibleDeclaration(_)) => tcx.sess.fatal(&format!(
76 "attempt to declare `{name}` as function, but it was already declared as static"
78 Err(ModuleError::IncompatibleSignature(_, prev_sig, new_sig)) => tcx.sess.fatal(&format!(
79 "attempt to declare `{name}` with signature {new_sig:?}, \
80 but it was already declared with signature {prev_sig:?}"
82 Err(err) => Err::<_, _>(err).unwrap(),
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.module, inst);
90 let func_ref = self.module.declare_func_in_func(func_id, &mut self.bcx.func);
92 if self.clif_comments.enabled() {
93 self.add_comment(func_ref, format!("{:?}", inst));
99 pub(crate) fn lib_call(
102 params: Vec<AbiParam>,
103 returns: Vec<AbiParam>,
106 let sig = Signature { params, returns, call_conv: self.target_config.default_call_conv };
107 let func_id = self.module.declare_function(name, Linkage::Import, &sig).unwrap();
108 let func_ref = self.module.declare_func_in_func(func_id, &mut self.bcx.func);
109 if self.clif_comments.enabled() {
110 self.add_comment(func_ref, format!("{:?}", name));
112 let call_inst = self.bcx.ins().call(func_ref, args);
113 if self.clif_comments.enabled() {
114 self.add_comment(call_inst, format!("easy_call {}", name));
116 let results = self.bcx.inst_results(call_inst);
117 assert!(results.len() <= 2, "{}", results.len());
121 pub(crate) fn easy_call(
124 args: &[CValue<'tcx>],
127 let (input_tys, args): (Vec<_>, Vec<_>) = args
130 (AbiParam::new(self.clif_type(arg.layout().ty).unwrap()), arg.load_scalar(self))
133 let return_layout = self.layout_of(return_ty);
134 let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
135 tup.iter().map(|ty| AbiParam::new(self.clif_type(ty).unwrap())).collect()
137 vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
139 let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
141 [] => CValue::by_ref(
142 Pointer::const_addr(self, i64::from(self.pointer_type.bytes())),
145 [val] => CValue::by_val(val, return_layout),
146 [val, extra] => CValue::by_val_pair(val, extra, return_layout),
152 /// Make a [`CPlace`] capable of holding value of the specified type.
153 fn make_local_place<'tcx>(
154 fx: &mut FunctionCx<'_, '_, 'tcx>,
156 layout: TyAndLayout<'tcx>,
159 let place = if is_ssa {
160 if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi {
161 CPlace::new_var_pair(fx, local, layout)
163 CPlace::new_var(fx, local, layout)
166 CPlace::new_stack_slot(fx, layout)
169 self::comments::add_local_place_comments(fx, place, local);
174 pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) {
175 fx.bcx.append_block_params_for_function_params(start_block);
177 fx.bcx.switch_to_block(start_block);
180 let ssa_analyzed = crate::analyze::analyze(fx);
182 self::comments::add_args_header_comment(fx);
184 let mut block_params_iter = fx.bcx.func.dfg.block_params(start_block).to_vec().into_iter();
186 self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
187 assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
189 // None means pass_mode == NoPass
191 Normal(Option<CValue<'tcx>>),
192 Spread(Vec<Option<CValue<'tcx>>>),
195 let fn_abi = fx.fn_abi.take().unwrap();
197 // FIXME implement variadics in cranelift
198 if fn_abi.c_variadic {
199 fx.tcx.sess.span_fatal(
201 "Defining variadic functions is not yet supported by Cranelift",
205 let mut arg_abis_iter = fn_abi.args.iter();
211 let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty);
213 // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
214 if Some(local) == fx.mir.spread_arg {
215 // This argument (e.g. the last argument in the "rust-call" ABI)
216 // is a tuple that was spread at the ABI level and now we have
217 // to reconstruct it into a tuple local variable, from multiple
218 // individual function arguments.
220 let tupled_arg_tys = match arg_ty.kind() {
221 ty::Tuple(ref tys) => tys,
222 _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
225 let mut params = Vec::new();
226 for (i, _arg_ty) in tupled_arg_tys.iter().enumerate() {
227 let arg_abi = arg_abis_iter.next().unwrap();
229 cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
233 (local, ArgKind::Spread(params), arg_ty)
235 let arg_abi = arg_abis_iter.next().unwrap();
237 cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
238 (local, ArgKind::Normal(param), arg_ty)
241 .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>();
243 assert!(fx.caller_location.is_none());
244 if fx.instance.def.requires_caller_location(fx.tcx) {
245 // Store caller location for `#[track_caller]`.
246 let arg_abi = arg_abis_iter.next().unwrap();
248 Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
251 assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
252 fx.fn_abi = Some(fn_abi);
253 assert!(block_params_iter.next().is_none(), "arg_value left behind");
255 self::comments::add_locals_header_comment(fx);
257 for (local, arg_kind, ty) in func_params {
258 let layout = fx.layout_of(ty);
260 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
262 // While this is normally an optimization to prevent an unnecessary copy when an argument is
263 // not mutated by the current function, this is necessary to support unsized arguments.
264 if let ArgKind::Normal(Some(val)) = arg_kind {
265 if let Some((addr, meta)) = val.try_to_ptr() {
266 // Ownership of the value at the backing storage for an argument is passed to the
267 // callee per the ABI, so it is fine to borrow the backing storage of this argument
268 // to prevent a copy.
270 let place = if let Some(meta) = meta {
271 CPlace::for_ptr_with_extra(addr, meta, val.layout())
273 CPlace::for_ptr(addr, val.layout())
276 self::comments::add_local_place_comments(fx, place, local);
278 assert_eq!(fx.local_map.push(place), local);
283 let place = make_local_place(fx, local, layout, is_ssa);
284 assert_eq!(fx.local_map.push(place), local);
287 ArgKind::Normal(param) => {
288 if let Some(param) = param {
289 place.write_cvalue(fx, param);
292 ArgKind::Spread(params) => {
293 for (i, param) in params.into_iter().enumerate() {
294 if let Some(param) = param {
295 place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param);
302 for local in fx.mir.vars_and_temps_iter() {
303 let ty = fx.monomorphize(fx.mir.local_decls[local].ty);
304 let layout = fx.layout_of(ty);
306 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
308 let place = make_local_place(fx, local, layout, is_ssa);
309 assert_eq!(fx.local_map.push(place), local);
312 fx.bcx.ins().jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]);
315 struct CallArgument<'tcx> {
320 // FIXME avoid intermediate `CValue` before calling `adjust_arg_for_abi`
321 fn codegen_call_argument_operand<'tcx>(
322 fx: &mut FunctionCx<'_, '_, 'tcx>,
323 operand: &Operand<'tcx>,
324 ) -> CallArgument<'tcx> {
326 value: codegen_operand(fx, operand),
327 is_owned: matches!(operand, Operand::Move(_)),
331 pub(crate) fn codegen_terminator_call<'tcx>(
332 fx: &mut FunctionCx<'_, '_, 'tcx>,
333 source_info: mir::SourceInfo,
334 func: &Operand<'tcx>,
335 args: &[Operand<'tcx>],
336 destination: Place<'tcx>,
337 target: Option<BasicBlock>,
339 let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
341 fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
343 let ret_place = codegen_place(fx, destination);
345 // Handle special calls like instrinsics and empty drop glue.
346 let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
347 let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
350 .polymorphize(fx.tcx);
352 if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
353 crate::intrinsics::codegen_llvm_intrinsic_call(
355 &fx.tcx.symbol_name(instance).name,
365 InstanceDef::Intrinsic(_) => {
366 crate::intrinsics::codegen_intrinsic_call(
376 InstanceDef::DropGlue(_, None) => {
377 // empty drop glue - a nop.
378 let dest = target.expect("Non terminating drop_in_place_real???");
379 let ret_block = fx.get_block(dest);
380 fx.bcx.ins().jump(ret_block, &[]);
389 let extra_args = &args[fn_sig.inputs().len()..];
392 .mk_type_list(extra_args.iter().map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx))));
393 let fn_abi = if let Some(instance) = instance {
394 RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(instance, extra_args)
396 RevealAllLayoutCx(fx.tcx).fn_abi_of_fn_ptr(fn_ty.fn_sig(fx.tcx), extra_args)
399 let is_cold = if fn_sig.abi == Abi::RustCold {
404 fx.tcx.codegen_fn_attrs(inst.def_id()).flags.contains(CodegenFnAttrFlags::COLD)
409 fx.bcx.set_cold_block(fx.bcx.current_block().unwrap());
410 if let Some(destination_block) = target {
411 fx.bcx.set_cold_block(fx.get_block(destination_block));
415 // Unpack arguments tuple for closures
416 let mut args = if fn_sig.abi == Abi::RustCall {
417 assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
418 let self_arg = codegen_call_argument_operand(fx, &args[0]);
419 let pack_arg = codegen_call_argument_operand(fx, &args[1]);
421 let tupled_arguments = match pack_arg.value.layout().ty.kind() {
422 ty::Tuple(ref tupled_arguments) => tupled_arguments,
423 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
426 let mut args = Vec::with_capacity(1 + tupled_arguments.len());
428 for i in 0..tupled_arguments.len() {
429 args.push(CallArgument {
430 value: pack_arg.value.value_field(fx, mir::Field::new(i)),
431 is_owned: pack_arg.is_owned,
436 args.iter().map(|arg| codegen_call_argument_operand(fx, arg)).collect::<Vec<_>>()
439 // Pass the caller location for `#[track_caller]`.
440 if instance.map(|inst| inst.def.requires_caller_location(fx.tcx)).unwrap_or(false) {
441 let caller_location = fx.get_caller_location(source_info);
442 args.push(CallArgument { value: caller_location, is_owned: false });
446 assert_eq!(fn_abi.args.len(), args.len());
450 Indirect(SigRef, Value),
453 let (func_ref, first_arg_override) = match instance {
455 Some(Instance { def: InstanceDef::Virtual(_, idx), .. }) => {
456 if fx.clif_comments.enabled() {
457 let nop_inst = fx.bcx.ins().nop();
460 format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0]),
464 let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0].value, idx);
465 let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi);
466 let sig = fx.bcx.import_signature(sig);
468 (CallTarget::Indirect(sig, method), Some(ptr))
473 let func_ref = fx.get_function_ref(instance);
474 (CallTarget::Direct(func_ref), None)
479 if fx.clif_comments.enabled() {
480 let nop_inst = fx.bcx.ins().nop();
481 fx.add_comment(nop_inst, "indirect call");
484 let func = codegen_operand(fx, func).load_scalar(fx);
485 let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi);
486 let sig = fx.bcx.import_signature(sig);
488 (CallTarget::Indirect(sig, func), None)
492 self::returning::codegen_with_call_return_arg(fx, &fn_abi.ret, ret_place, |fx, return_ptr| {
493 let call_args = return_ptr
495 .chain(first_arg_override.into_iter())
499 .skip(if first_arg_override.is_some() { 1 } else { 0 })
501 adjust_arg_for_abi(fx, arg.value, &fn_abi.args[i], arg.is_owned).into_iter()
505 .collect::<Vec<Value>>();
507 let call_inst = match func_ref {
508 CallTarget::Direct(func_ref) => fx.bcx.ins().call(func_ref, &call_args),
509 CallTarget::Indirect(sig, func_ptr) => {
510 fx.bcx.ins().call_indirect(sig, func_ptr, &call_args)
514 // FIXME find a cleaner way to support varargs
515 if fn_sig.c_variadic {
516 if !matches!(fn_sig.abi, Abi::C { .. }) {
517 fx.tcx.sess.span_fatal(
519 &format!("Variadic call for non-C abi {:?}", fn_sig.abi),
522 let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap();
523 let abi_params = call_args
526 let ty = fx.bcx.func.dfg.value_type(arg);
528 // FIXME set %al to upperbound on float args once floats are supported
529 fx.tcx.sess.span_fatal(
531 &format!("Non int ty {:?} for variadic call", ty),
536 .collect::<Vec<AbiParam>>();
537 fx.bcx.func.dfg.signatures[sig_ref].params = abi_params;
543 if let Some(dest) = target {
544 let ret_block = fx.get_block(dest);
545 fx.bcx.ins().jump(ret_block, &[]);
547 fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
551 pub(crate) fn codegen_drop<'tcx>(
552 fx: &mut FunctionCx<'_, '_, 'tcx>,
553 source_info: mir::SourceInfo,
554 drop_place: CPlace<'tcx>,
556 let ty = drop_place.layout().ty;
557 let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
559 if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
560 // we don't actually need to drop anything
564 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
565 let ptr = ptr.get_addr(fx);
566 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
568 // FIXME(eddyb) perhaps move some of this logic into
569 // `Instance::resolve_drop_in_place`?
570 let virtual_drop = Instance {
571 def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
572 substs: drop_instance.substs,
575 RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(virtual_drop, ty::List::empty());
577 let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi);
578 let sig = fx.bcx.import_signature(sig);
579 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
582 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
585 RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(drop_instance, ty::List::empty());
587 let arg_value = drop_place.place_ref(
589 fx.layout_of(fx.tcx.mk_ref(
590 fx.tcx.lifetimes.re_erased,
591 TypeAndMut { ty, mutbl: crate::rustc_hir::Mutability::Mut },
594 let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0], true);
596 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
598 if drop_instance.def.requires_caller_location(fx.tcx) {
599 // Pass the caller location for `#[track_caller]`.
600 let caller_location = fx.get_caller_location(source_info);
602 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1], false).into_iter(),
606 let func_ref = fx.get_function_ref(drop_instance);
607 fx.bcx.ins().call(func_ref, &call_args);