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::FnAbiExt;
9 use rustc_target::abi::call::{Conv, FnAbi};
10 use rustc_target::spec::abi::Abi;
12 use cranelift_codegen::ir::AbiParam;
13 use smallvec::smallvec;
15 use self::pass_mode::*;
16 use crate::prelude::*;
18 pub(crate) use self::returning::{can_return_to_ssa_var, codegen_return};
20 fn clif_sig_from_fn_abi<'tcx>(
22 triple: &target_lexicon::Triple,
23 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
25 let call_conv = match fn_abi.conv {
26 Conv::Rust | Conv::C => CallConv::triple_default(triple),
27 Conv::X86_64SysV => CallConv::SystemV,
28 Conv::X86_64Win64 => CallConv::WindowsFastcall,
30 | Conv::CCmseNonSecureCall
40 | Conv::AvrNonBlockingInterrupt => todo!("{:?}", fn_abi.conv),
42 let inputs = fn_abi.args.iter().map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter()).flatten();
44 let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx);
45 // Sometimes the first param is an pointer to the place where the return value needs to be stored.
46 let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect();
48 Signature { params, returns, call_conv }
51 pub(crate) fn get_function_sig<'tcx>(
53 triple: &target_lexicon::Triple,
56 assert!(!inst.substs.needs_infer());
57 clif_sig_from_fn_abi(tcx, triple, &FnAbi::of_instance(&RevealAllLayoutCx(tcx), inst, &[]))
60 /// Instance must be monomorphized
61 pub(crate) fn import_function<'tcx>(
63 module: &mut dyn Module,
66 let name = tcx.symbol_name(inst).name.to_string();
67 let sig = get_function_sig(tcx, module.isa().triple(), inst);
68 module.declare_function(&name, Linkage::Import, &sig).unwrap()
71 impl<'tcx> FunctionCx<'_, '_, 'tcx> {
72 /// Instance must be monomorphized
73 pub(crate) fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef {
74 let func_id = import_function(self.tcx, self.cx.module, inst);
75 let func_ref = self.cx.module.declare_func_in_func(func_id, &mut self.bcx.func);
77 if self.clif_comments.enabled() {
78 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 if self.clif_comments.enabled() {
96 self.add_comment(call_inst, format!("easy_call {}", name));
98 let results = self.bcx.inst_results(call_inst);
99 assert!(results.len() <= 2, "{}", results.len());
103 pub(crate) fn easy_call(
106 args: &[CValue<'tcx>],
109 let (input_tys, args): (Vec<_>, Vec<_>) = args
112 (AbiParam::new(self.clif_type(arg.layout().ty).unwrap()), arg.load_scalar(self))
115 let return_layout = self.layout_of(return_ty);
116 let return_tys = if let ty::Tuple(tup) = return_ty.kind() {
117 tup.types().map(|ty| AbiParam::new(self.clif_type(ty).unwrap())).collect()
119 vec![AbiParam::new(self.clif_type(return_ty).unwrap())]
121 let ret_vals = self.lib_call(name, input_tys, return_tys, &args);
123 [] => CValue::by_ref(
124 Pointer::const_addr(self, i64::from(self.pointer_type.bytes())),
127 [val] => CValue::by_val(val, return_layout),
128 [val, extra] => CValue::by_val_pair(val, extra, return_layout),
134 /// Make a [`CPlace`] capable of holding value of the specified type.
135 fn make_local_place<'tcx>(
136 fx: &mut FunctionCx<'_, '_, 'tcx>,
138 layout: TyAndLayout<'tcx>,
141 let place = if is_ssa {
142 if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi {
143 CPlace::new_var_pair(fx, local, layout)
145 CPlace::new_var(fx, local, layout)
148 CPlace::new_stack_slot(fx, layout)
151 self::comments::add_local_place_comments(fx, place, local);
156 pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) {
157 fx.bcx.append_block_params_for_function_params(start_block);
159 fx.bcx.switch_to_block(start_block);
162 let ssa_analyzed = crate::analyze::analyze(fx);
164 self::comments::add_args_header_comment(fx);
166 let mut block_params_iter = fx.bcx.func.dfg.block_params(start_block).to_vec().into_iter();
168 self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter);
169 assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE);
171 // None means pass_mode == NoPass
173 Normal(Option<CValue<'tcx>>),
174 Spread(Vec<Option<CValue<'tcx>>>),
177 let fn_abi = fx.fn_abi.take().unwrap();
178 let mut arg_abis_iter = fn_abi.args.iter();
184 let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty);
186 // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482
187 if Some(local) == fx.mir.spread_arg {
188 // This argument (e.g. the last argument in the "rust-call" ABI)
189 // is a tuple that was spread at the ABI level and now we have
190 // to reconstruct it into a tuple local variable, from multiple
191 // individual function arguments.
193 let tupled_arg_tys = match arg_ty.kind() {
194 ty::Tuple(ref tys) => tys,
195 _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty),
198 let mut params = Vec::new();
199 for (i, _arg_ty) in tupled_arg_tys.types().enumerate() {
200 let arg_abi = arg_abis_iter.next().unwrap();
202 cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter);
206 (local, ArgKind::Spread(params), arg_ty)
208 let arg_abi = arg_abis_iter.next().unwrap();
210 cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter);
211 (local, ArgKind::Normal(param), arg_ty)
214 .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>();
216 assert!(fx.caller_location.is_none());
217 if fx.instance.def.requires_caller_location(fx.tcx) {
218 // Store caller location for `#[track_caller]`.
219 let arg_abi = arg_abis_iter.next().unwrap();
221 Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap());
224 assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind");
225 fx.fn_abi = Some(fn_abi);
226 assert!(block_params_iter.next().is_none(), "arg_value left behind");
228 self::comments::add_locals_header_comment(fx);
230 for (local, arg_kind, ty) in func_params {
231 let layout = fx.layout_of(ty);
233 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
235 // While this is normally an optimization to prevent an unnecessary copy when an argument is
236 // not mutated by the current function, this is necessary to support unsized arguments.
237 if let ArgKind::Normal(Some(val)) = arg_kind {
238 if let Some((addr, meta)) = val.try_to_ptr() {
239 let local_decl = &fx.mir.local_decls[local];
240 // v this ! is important
241 let internally_mutable = !val
244 .is_freeze(fx.tcx.at(local_decl.source_info.span), ParamEnv::reveal_all());
245 if local_decl.mutability == mir::Mutability::Not && !internally_mutable {
246 // We wont mutate this argument, so it is fine to borrow the backing storage
247 // of this argument, 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);
263 let place = make_local_place(fx, local, layout, is_ssa);
264 assert_eq!(fx.local_map.push(place), local);
267 ArgKind::Normal(param) => {
268 if let Some(param) = param {
269 place.write_cvalue(fx, param);
272 ArgKind::Spread(params) => {
273 for (i, param) in params.into_iter().enumerate() {
274 if let Some(param) = param {
275 place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param);
282 for local in fx.mir.vars_and_temps_iter() {
283 let ty = fx.monomorphize(fx.mir.local_decls[local].ty);
284 let layout = fx.layout_of(ty);
286 let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa;
288 let place = make_local_place(fx, local, layout, is_ssa);
289 assert_eq!(fx.local_map.push(place), local);
292 fx.bcx.ins().jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]);
295 pub(crate) fn codegen_terminator_call<'tcx>(
296 fx: &mut FunctionCx<'_, '_, 'tcx>,
298 current_block: Block,
299 func: &Operand<'tcx>,
300 args: &[Operand<'tcx>],
301 destination: Option<(Place<'tcx>, BasicBlock)>,
303 let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx));
305 fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx));
307 let destination = destination.map(|(place, bb)| (codegen_place(fx, place), bb));
309 // Handle special calls like instrinsics and empty drop glue.
310 let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() {
311 let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs)
314 .polymorphize(fx.tcx);
316 if fx.tcx.symbol_name(instance).name.starts_with("llvm.") {
317 crate::intrinsics::codegen_llvm_intrinsic_call(
319 &fx.tcx.symbol_name(instance).name,
328 InstanceDef::Intrinsic(_) => {
329 crate::intrinsics::codegen_intrinsic_call(fx, instance, args, destination, span);
332 InstanceDef::DropGlue(_, None) => {
333 // empty drop glue - a nop.
334 let (_, dest) = destination.expect("Non terminating drop_in_place_real???");
335 let ret_block = fx.get_block(dest);
336 fx.bcx.ins().jump(ret_block, &[]);
345 let extra_args = &args[fn_sig.inputs().len()..];
346 let extra_args = extra_args
348 .map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx)))
349 .collect::<Vec<_>>();
350 let fn_abi = if let Some(instance) = instance {
351 FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), instance, &extra_args)
353 FnAbi::of_fn_ptr(&RevealAllLayoutCx(fx.tcx), fn_ty.fn_sig(fx.tcx), &extra_args)
356 let is_cold = instance
357 .map(|inst| fx.tcx.codegen_fn_attrs(inst.def_id()).flags.contains(CodegenFnAttrFlags::COLD))
360 fx.cold_blocks.insert(current_block);
363 // Unpack arguments tuple for closures
364 let args = if fn_sig.abi == Abi::RustCall {
365 assert_eq!(args.len(), 2, "rust-call abi requires two arguments");
366 let self_arg = codegen_operand(fx, &args[0]);
367 let pack_arg = codegen_operand(fx, &args[1]);
369 let tupled_arguments = match pack_arg.layout().ty.kind() {
370 ty::Tuple(ref tupled_arguments) => tupled_arguments,
371 _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"),
374 let mut args = Vec::with_capacity(1 + tupled_arguments.len());
376 for i in 0..tupled_arguments.len() {
377 args.push(pack_arg.value_field(fx, mir::Field::new(i)));
381 args.iter().map(|arg| codegen_operand(fx, arg)).collect::<Vec<_>>()
384 // | indirect call target
385 // | | the first argument to be passed
387 let (func_ref, first_arg) = match instance {
389 Some(Instance { def: InstanceDef::Virtual(_, idx), .. }) => {
390 if fx.clif_comments.enabled() {
391 let nop_inst = fx.bcx.ins().nop();
394 format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0],),
397 let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0], idx);
398 (Some(method), smallvec![ptr])
405 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
406 .unwrap_or(smallvec![]),
411 if fx.clif_comments.enabled() {
412 let nop_inst = fx.bcx.ins().nop();
413 fx.add_comment(nop_inst, "indirect call");
415 let func = codegen_operand(fx, func).load_scalar(fx);
419 .map(|arg| adjust_arg_for_abi(fx, *arg, &fn_abi.args[0]))
420 .unwrap_or(smallvec![]),
425 let ret_place = destination.map(|(place, _)| place);
426 let (call_inst, call_args) = self::returning::codegen_with_call_return_arg(
431 let regular_args_count = args.len();
432 let mut call_args: Vec<Value> = return_ptr
434 .chain(first_arg.into_iter())
439 .map(|(i, arg)| adjust_arg_for_abi(fx, arg, &fn_abi.args[i]).into_iter())
442 .collect::<Vec<_>>();
444 if instance.map(|inst| inst.def.requires_caller_location(fx.tcx)).unwrap_or(false) {
445 // Pass the caller location for `#[track_caller]`.
446 let caller_location = fx.get_caller_location(span);
448 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[regular_args_count])
451 assert_eq!(fn_abi.args.len(), regular_args_count + 1);
453 assert_eq!(fn_abi.args.len(), regular_args_count);
456 let call_inst = if let Some(func_ref) = func_ref {
457 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
458 let sig = fx.bcx.import_signature(sig);
459 fx.bcx.ins().call_indirect(sig, func_ref, &call_args)
462 fx.get_function_ref(instance.expect("non-indirect call on non-FnDef type"));
463 fx.bcx.ins().call(func_ref, &call_args)
466 (call_inst, call_args)
470 // FIXME find a cleaner way to support varargs
471 if fn_sig.c_variadic {
472 if !matches!(fn_sig.abi, Abi::C { .. }) {
473 fx.tcx.sess.span_fatal(
475 &format!("Variadic call for non-C abi {:?}", fn_sig.abi),
478 let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap();
479 let abi_params = call_args
482 let ty = fx.bcx.func.dfg.value_type(arg);
484 // FIXME set %al to upperbound on float args once floats are supported
485 fx.tcx.sess.span_fatal(span, &format!("Non int ty {:?} for variadic call", ty));
489 .collect::<Vec<AbiParam>>();
490 fx.bcx.func.dfg.signatures[sig_ref].params = abi_params;
493 if let Some((_, dest)) = destination {
494 let ret_block = fx.get_block(dest);
495 fx.bcx.ins().jump(ret_block, &[]);
497 trap_unreachable(fx, "[corruption] Diverging function returned");
501 pub(crate) fn codegen_drop<'tcx>(
502 fx: &mut FunctionCx<'_, '_, 'tcx>,
504 drop_place: CPlace<'tcx>,
506 let ty = drop_place.layout().ty;
507 let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx);
509 if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def {
510 // we don't actually need to drop anything
514 let (ptr, vtable) = drop_place.to_ptr_maybe_unsized();
515 let ptr = ptr.get_addr(fx);
516 let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap());
518 // FIXME(eddyb) perhaps move some of this logic into
519 // `Instance::resolve_drop_in_place`?
520 let virtual_drop = Instance {
521 def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0),
522 substs: drop_instance.substs,
524 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), virtual_drop, &[]);
526 let sig = clif_sig_from_fn_abi(fx.tcx, fx.triple(), &fn_abi);
527 let sig = fx.bcx.import_signature(sig);
528 fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]);
531 assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _)));
533 let fn_abi = FnAbi::of_instance(&RevealAllLayoutCx(fx.tcx), drop_instance, &[]);
535 let arg_value = drop_place.place_ref(
537 fx.layout_of(fx.tcx.mk_ref(
538 &ty::RegionKind::ReErased,
539 TypeAndMut { ty, mutbl: crate::rustc_hir::Mutability::Mut },
542 let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0]);
544 let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>();
546 if drop_instance.def.requires_caller_location(fx.tcx) {
547 // Pass the caller location for `#[track_caller]`.
548 let caller_location = fx.get_caller_location(span);
550 adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1]).into_iter(),
554 let func_ref = fx.get_function_ref(drop_instance);
555 fx.bcx.ins().call(func_ref, &call_args);