diff options
Diffstat (limited to 'compiler/rustc_codegen_cranelift/src/abi/mod.rs')
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/abi/mod.rs | 611 |
1 files changed, 611 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/abi/mod.rs b/compiler/rustc_codegen_cranelift/src/abi/mod.rs new file mode 100644 index 000000000..815450f68 --- /dev/null +++ b/compiler/rustc_codegen_cranelift/src/abi/mod.rs @@ -0,0 +1,611 @@ +//! Handling of everything related to the calling convention. Also fills `fx.local_map`. + +mod comments; +mod pass_mode; +mod returning; + +use cranelift_module::ModuleError; +use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags; +use rustc_middle::ty::layout::FnAbiOf; +use rustc_target::abi::call::{Conv, FnAbi}; +use rustc_target::spec::abi::Abi; + +use cranelift_codegen::ir::{AbiParam, SigRef}; + +use self::pass_mode::*; +use crate::prelude::*; + +pub(crate) use self::returning::codegen_return; + +fn clif_sig_from_fn_abi<'tcx>( + tcx: TyCtxt<'tcx>, + default_call_conv: CallConv, + fn_abi: &FnAbi<'tcx, Ty<'tcx>>, +) -> Signature { + let call_conv = match fn_abi.conv { + Conv::Rust | Conv::C => default_call_conv, + Conv::RustCold => CallConv::Cold, + Conv::X86_64SysV => CallConv::SystemV, + Conv::X86_64Win64 => CallConv::WindowsFastcall, + Conv::ArmAapcs + | Conv::CCmseNonSecureCall + | Conv::Msp430Intr + | Conv::PtxKernel + | Conv::X86Fastcall + | Conv::X86Intr + | Conv::X86Stdcall + | Conv::X86ThisCall + | Conv::X86VectorCall + | Conv::AmdGpuKernel + | Conv::AvrInterrupt + | Conv::AvrNonBlockingInterrupt => todo!("{:?}", fn_abi.conv), + }; + let inputs = fn_abi.args.iter().map(|arg_abi| arg_abi.get_abi_param(tcx).into_iter()).flatten(); + + let (return_ptr, returns) = fn_abi.ret.get_abi_return(tcx); + // Sometimes the first param is an pointer to the place where the return value needs to be stored. + let params: Vec<_> = return_ptr.into_iter().chain(inputs).collect(); + + Signature { params, returns, call_conv } +} + +pub(crate) fn get_function_sig<'tcx>( + tcx: TyCtxt<'tcx>, + triple: &target_lexicon::Triple, + inst: Instance<'tcx>, +) -> Signature { + assert!(!inst.substs.needs_infer()); + clif_sig_from_fn_abi( + tcx, + CallConv::triple_default(triple), + &RevealAllLayoutCx(tcx).fn_abi_of_instance(inst, ty::List::empty()), + ) +} + +/// Instance must be monomorphized +pub(crate) fn import_function<'tcx>( + tcx: TyCtxt<'tcx>, + module: &mut dyn Module, + inst: Instance<'tcx>, +) -> FuncId { + let name = tcx.symbol_name(inst).name; + let sig = get_function_sig(tcx, module.isa().triple(), inst); + match module.declare_function(name, Linkage::Import, &sig) { + Ok(func_id) => func_id, + Err(ModuleError::IncompatibleDeclaration(_)) => tcx.sess.fatal(&format!( + "attempt to declare `{name}` as function, but it was already declared as static" + )), + Err(ModuleError::IncompatibleSignature(_, prev_sig, new_sig)) => tcx.sess.fatal(&format!( + "attempt to declare `{name}` with signature {new_sig:?}, \ + but it was already declared with signature {prev_sig:?}" + )), + Err(err) => Err::<_, _>(err).unwrap(), + } +} + +impl<'tcx> FunctionCx<'_, '_, 'tcx> { + /// Instance must be monomorphized + pub(crate) fn get_function_ref(&mut self, inst: Instance<'tcx>) -> FuncRef { + let func_id = import_function(self.tcx, self.module, inst); + let func_ref = self.module.declare_func_in_func(func_id, &mut self.bcx.func); + + if self.clif_comments.enabled() { + self.add_comment(func_ref, format!("{:?}", inst)); + } + + func_ref + } + + pub(crate) fn lib_call( + &mut self, + name: &str, + params: Vec<AbiParam>, + returns: Vec<AbiParam>, + args: &[Value], + ) -> &[Value] { + let sig = Signature { params, returns, call_conv: self.target_config.default_call_conv }; + let func_id = self.module.declare_function(name, Linkage::Import, &sig).unwrap(); + let func_ref = self.module.declare_func_in_func(func_id, &mut self.bcx.func); + if self.clif_comments.enabled() { + self.add_comment(func_ref, format!("{:?}", name)); + } + let call_inst = self.bcx.ins().call(func_ref, args); + if self.clif_comments.enabled() { + self.add_comment(call_inst, format!("easy_call {}", name)); + } + let results = self.bcx.inst_results(call_inst); + assert!(results.len() <= 2, "{}", results.len()); + results + } + + pub(crate) fn easy_call( + &mut self, + name: &str, + args: &[CValue<'tcx>], + return_ty: Ty<'tcx>, + ) -> CValue<'tcx> { + let (input_tys, args): (Vec<_>, Vec<_>) = args + .iter() + .map(|arg| { + (AbiParam::new(self.clif_type(arg.layout().ty).unwrap()), arg.load_scalar(self)) + }) + .unzip(); + let return_layout = self.layout_of(return_ty); + let return_tys = if let ty::Tuple(tup) = return_ty.kind() { + tup.iter().map(|ty| AbiParam::new(self.clif_type(ty).unwrap())).collect() + } else { + vec![AbiParam::new(self.clif_type(return_ty).unwrap())] + }; + let ret_vals = self.lib_call(name, input_tys, return_tys, &args); + match *ret_vals { + [] => CValue::by_ref( + Pointer::const_addr(self, i64::from(self.pointer_type.bytes())), + return_layout, + ), + [val] => CValue::by_val(val, return_layout), + [val, extra] => CValue::by_val_pair(val, extra, return_layout), + _ => unreachable!(), + } + } +} + +/// Make a [`CPlace`] capable of holding value of the specified type. +fn make_local_place<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + local: Local, + layout: TyAndLayout<'tcx>, + is_ssa: bool, +) -> CPlace<'tcx> { + let place = if is_ssa { + if let rustc_target::abi::Abi::ScalarPair(_, _) = layout.abi { + CPlace::new_var_pair(fx, local, layout) + } else { + CPlace::new_var(fx, local, layout) + } + } else { + CPlace::new_stack_slot(fx, layout) + }; + + self::comments::add_local_place_comments(fx, place, local); + + place +} + +pub(crate) fn codegen_fn_prelude<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, start_block: Block) { + fx.bcx.append_block_params_for_function_params(start_block); + + fx.bcx.switch_to_block(start_block); + fx.bcx.ins().nop(); + + let ssa_analyzed = crate::analyze::analyze(fx); + + self::comments::add_args_header_comment(fx); + + let mut block_params_iter = fx.bcx.func.dfg.block_params(start_block).to_vec().into_iter(); + let ret_place = + self::returning::codegen_return_param(fx, &ssa_analyzed, &mut block_params_iter); + assert_eq!(fx.local_map.push(ret_place), RETURN_PLACE); + + // None means pass_mode == NoPass + enum ArgKind<'tcx> { + Normal(Option<CValue<'tcx>>), + Spread(Vec<Option<CValue<'tcx>>>), + } + + let fn_abi = fx.fn_abi.take().unwrap(); + + // FIXME implement variadics in cranelift + if fn_abi.c_variadic { + fx.tcx.sess.span_fatal( + fx.mir.span, + "Defining variadic functions is not yet supported by Cranelift", + ); + } + + let mut arg_abis_iter = fn_abi.args.iter(); + + let func_params = fx + .mir + .args_iter() + .map(|local| { + let arg_ty = fx.monomorphize(fx.mir.local_decls[local].ty); + + // Adapted from https://github.com/rust-lang/rust/blob/145155dc96757002c7b2e9de8489416e2fdbbd57/src/librustc_codegen_llvm/mir/mod.rs#L442-L482 + if Some(local) == fx.mir.spread_arg { + // This argument (e.g. the last argument in the "rust-call" ABI) + // is a tuple that was spread at the ABI level and now we have + // to reconstruct it into a tuple local variable, from multiple + // individual function arguments. + + let tupled_arg_tys = match arg_ty.kind() { + ty::Tuple(ref tys) => tys, + _ => bug!("spread argument isn't a tuple?! but {:?}", arg_ty), + }; + + let mut params = Vec::new(); + for (i, _arg_ty) in tupled_arg_tys.iter().enumerate() { + let arg_abi = arg_abis_iter.next().unwrap(); + let param = + cvalue_for_param(fx, Some(local), Some(i), arg_abi, &mut block_params_iter); + params.push(param); + } + + (local, ArgKind::Spread(params), arg_ty) + } else { + let arg_abi = arg_abis_iter.next().unwrap(); + let param = + cvalue_for_param(fx, Some(local), None, arg_abi, &mut block_params_iter); + (local, ArgKind::Normal(param), arg_ty) + } + }) + .collect::<Vec<(Local, ArgKind<'tcx>, Ty<'tcx>)>>(); + + assert!(fx.caller_location.is_none()); + if fx.instance.def.requires_caller_location(fx.tcx) { + // Store caller location for `#[track_caller]`. + let arg_abi = arg_abis_iter.next().unwrap(); + fx.caller_location = + Some(cvalue_for_param(fx, None, None, arg_abi, &mut block_params_iter).unwrap()); + } + + assert!(arg_abis_iter.next().is_none(), "ArgAbi left behind"); + fx.fn_abi = Some(fn_abi); + assert!(block_params_iter.next().is_none(), "arg_value left behind"); + + self::comments::add_locals_header_comment(fx); + + for (local, arg_kind, ty) in func_params { + let layout = fx.layout_of(ty); + + let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa; + + // While this is normally an optimization to prevent an unnecessary copy when an argument is + // not mutated by the current function, this is necessary to support unsized arguments. + if let ArgKind::Normal(Some(val)) = arg_kind { + if let Some((addr, meta)) = val.try_to_ptr() { + // Ownership of the value at the backing storage for an argument is passed to the + // callee per the ABI, so it is fine to borrow the backing storage of this argument + // to prevent a copy. + + let place = if let Some(meta) = meta { + CPlace::for_ptr_with_extra(addr, meta, val.layout()) + } else { + CPlace::for_ptr(addr, val.layout()) + }; + + self::comments::add_local_place_comments(fx, place, local); + + assert_eq!(fx.local_map.push(place), local); + continue; + } + } + + let place = make_local_place(fx, local, layout, is_ssa); + assert_eq!(fx.local_map.push(place), local); + + match arg_kind { + ArgKind::Normal(param) => { + if let Some(param) = param { + place.write_cvalue(fx, param); + } + } + ArgKind::Spread(params) => { + for (i, param) in params.into_iter().enumerate() { + if let Some(param) = param { + place.place_field(fx, mir::Field::new(i)).write_cvalue(fx, param); + } + } + } + } + } + + for local in fx.mir.vars_and_temps_iter() { + let ty = fx.monomorphize(fx.mir.local_decls[local].ty); + let layout = fx.layout_of(ty); + + let is_ssa = ssa_analyzed[local] == crate::analyze::SsaKind::Ssa; + + let place = make_local_place(fx, local, layout, is_ssa); + assert_eq!(fx.local_map.push(place), local); + } + + fx.bcx.ins().jump(*fx.block_map.get(START_BLOCK).unwrap(), &[]); +} + +struct CallArgument<'tcx> { + value: CValue<'tcx>, + is_owned: bool, +} + +// FIXME avoid intermediate `CValue` before calling `adjust_arg_for_abi` +fn codegen_call_argument_operand<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + operand: &Operand<'tcx>, +) -> CallArgument<'tcx> { + CallArgument { + value: codegen_operand(fx, operand), + is_owned: matches!(operand, Operand::Move(_)), + } +} + +pub(crate) fn codegen_terminator_call<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + source_info: mir::SourceInfo, + func: &Operand<'tcx>, + args: &[Operand<'tcx>], + destination: Place<'tcx>, + target: Option<BasicBlock>, +) { + let fn_ty = fx.monomorphize(func.ty(fx.mir, fx.tcx)); + let fn_sig = + fx.tcx.normalize_erasing_late_bound_regions(ParamEnv::reveal_all(), fn_ty.fn_sig(fx.tcx)); + + let ret_place = codegen_place(fx, destination); + + // Handle special calls like instrinsics and empty drop glue. + let instance = if let ty::FnDef(def_id, substs) = *fn_ty.kind() { + let instance = ty::Instance::resolve(fx.tcx, ty::ParamEnv::reveal_all(), def_id, substs) + .unwrap() + .unwrap() + .polymorphize(fx.tcx); + + if fx.tcx.symbol_name(instance).name.starts_with("llvm.") { + crate::intrinsics::codegen_llvm_intrinsic_call( + fx, + &fx.tcx.symbol_name(instance).name, + substs, + args, + ret_place, + target, + ); + return; + } + + match instance.def { + InstanceDef::Intrinsic(_) => { + crate::intrinsics::codegen_intrinsic_call( + fx, + instance, + args, + ret_place, + target, + source_info, + ); + return; + } + InstanceDef::DropGlue(_, None) => { + // empty drop glue - a nop. + let dest = target.expect("Non terminating drop_in_place_real???"); + let ret_block = fx.get_block(dest); + fx.bcx.ins().jump(ret_block, &[]); + return; + } + _ => Some(instance), + } + } else { + None + }; + + let extra_args = &args[fn_sig.inputs().len()..]; + let extra_args = fx + .tcx + .mk_type_list(extra_args.iter().map(|op_arg| fx.monomorphize(op_arg.ty(fx.mir, fx.tcx)))); + let fn_abi = if let Some(instance) = instance { + RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(instance, extra_args) + } else { + RevealAllLayoutCx(fx.tcx).fn_abi_of_fn_ptr(fn_ty.fn_sig(fx.tcx), extra_args) + }; + + let is_cold = if fn_sig.abi == Abi::RustCold { + true + } else { + instance + .map(|inst| { + fx.tcx.codegen_fn_attrs(inst.def_id()).flags.contains(CodegenFnAttrFlags::COLD) + }) + .unwrap_or(false) + }; + if is_cold { + fx.bcx.set_cold_block(fx.bcx.current_block().unwrap()); + if let Some(destination_block) = target { + fx.bcx.set_cold_block(fx.get_block(destination_block)); + } + } + + // Unpack arguments tuple for closures + let mut args = if fn_sig.abi == Abi::RustCall { + assert_eq!(args.len(), 2, "rust-call abi requires two arguments"); + let self_arg = codegen_call_argument_operand(fx, &args[0]); + let pack_arg = codegen_call_argument_operand(fx, &args[1]); + + let tupled_arguments = match pack_arg.value.layout().ty.kind() { + ty::Tuple(ref tupled_arguments) => tupled_arguments, + _ => bug!("argument to function with \"rust-call\" ABI is not a tuple"), + }; + + let mut args = Vec::with_capacity(1 + tupled_arguments.len()); + args.push(self_arg); + for i in 0..tupled_arguments.len() { + args.push(CallArgument { + value: pack_arg.value.value_field(fx, mir::Field::new(i)), + is_owned: pack_arg.is_owned, + }); + } + args + } else { + args.iter().map(|arg| codegen_call_argument_operand(fx, arg)).collect::<Vec<_>>() + }; + + // Pass the caller location for `#[track_caller]`. + if instance.map(|inst| inst.def.requires_caller_location(fx.tcx)).unwrap_or(false) { + let caller_location = fx.get_caller_location(source_info); + args.push(CallArgument { value: caller_location, is_owned: false }); + } + + let args = args; + assert_eq!(fn_abi.args.len(), args.len()); + + enum CallTarget { + Direct(FuncRef), + Indirect(SigRef, Value), + } + + let (func_ref, first_arg_override) = match instance { + // Trait object call + Some(Instance { def: InstanceDef::Virtual(_, idx), .. }) => { + if fx.clif_comments.enabled() { + let nop_inst = fx.bcx.ins().nop(); + fx.add_comment( + nop_inst, + format!("virtual call; self arg pass mode: {:?}", &fn_abi.args[0]), + ); + } + + let (ptr, method) = crate::vtable::get_ptr_and_method_ref(fx, args[0].value, idx); + let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi); + let sig = fx.bcx.import_signature(sig); + + (CallTarget::Indirect(sig, method), Some(ptr)) + } + + // Normal call + Some(instance) => { + let func_ref = fx.get_function_ref(instance); + (CallTarget::Direct(func_ref), None) + } + + // Indirect call + None => { + if fx.clif_comments.enabled() { + let nop_inst = fx.bcx.ins().nop(); + fx.add_comment(nop_inst, "indirect call"); + } + + let func = codegen_operand(fx, func).load_scalar(fx); + let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi); + let sig = fx.bcx.import_signature(sig); + + (CallTarget::Indirect(sig, func), None) + } + }; + + self::returning::codegen_with_call_return_arg(fx, &fn_abi.ret, ret_place, |fx, return_ptr| { + let call_args = return_ptr + .into_iter() + .chain(first_arg_override.into_iter()) + .chain( + args.into_iter() + .enumerate() + .skip(if first_arg_override.is_some() { 1 } else { 0 }) + .map(|(i, arg)| { + adjust_arg_for_abi(fx, arg.value, &fn_abi.args[i], arg.is_owned).into_iter() + }) + .flatten(), + ) + .collect::<Vec<Value>>(); + + let call_inst = match func_ref { + CallTarget::Direct(func_ref) => fx.bcx.ins().call(func_ref, &call_args), + CallTarget::Indirect(sig, func_ptr) => { + fx.bcx.ins().call_indirect(sig, func_ptr, &call_args) + } + }; + + // FIXME find a cleaner way to support varargs + if fn_sig.c_variadic { + if !matches!(fn_sig.abi, Abi::C { .. }) { + fx.tcx.sess.span_fatal( + source_info.span, + &format!("Variadic call for non-C abi {:?}", fn_sig.abi), + ); + } + let sig_ref = fx.bcx.func.dfg.call_signature(call_inst).unwrap(); + let abi_params = call_args + .into_iter() + .map(|arg| { + let ty = fx.bcx.func.dfg.value_type(arg); + if !ty.is_int() { + // FIXME set %al to upperbound on float args once floats are supported + fx.tcx.sess.span_fatal( + source_info.span, + &format!("Non int ty {:?} for variadic call", ty), + ); + } + AbiParam::new(ty) + }) + .collect::<Vec<AbiParam>>(); + fx.bcx.func.dfg.signatures[sig_ref].params = abi_params; + } + + call_inst + }); + + if let Some(dest) = target { + let ret_block = fx.get_block(dest); + fx.bcx.ins().jump(ret_block, &[]); + } else { + fx.bcx.ins().trap(TrapCode::UnreachableCodeReached); + } +} + +pub(crate) fn codegen_drop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + source_info: mir::SourceInfo, + drop_place: CPlace<'tcx>, +) { + let ty = drop_place.layout().ty; + let drop_instance = Instance::resolve_drop_in_place(fx.tcx, ty).polymorphize(fx.tcx); + + if let ty::InstanceDef::DropGlue(_, None) = drop_instance.def { + // we don't actually need to drop anything + } else { + match ty.kind() { + ty::Dynamic(..) => { + let (ptr, vtable) = drop_place.to_ptr_maybe_unsized(); + let ptr = ptr.get_addr(fx); + let drop_fn = crate::vtable::drop_fn_of_obj(fx, vtable.unwrap()); + + // FIXME(eddyb) perhaps move some of this logic into + // `Instance::resolve_drop_in_place`? + let virtual_drop = Instance { + def: ty::InstanceDef::Virtual(drop_instance.def_id(), 0), + substs: drop_instance.substs, + }; + let fn_abi = + RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(virtual_drop, ty::List::empty()); + + let sig = clif_sig_from_fn_abi(fx.tcx, fx.target_config.default_call_conv, &fn_abi); + let sig = fx.bcx.import_signature(sig); + fx.bcx.ins().call_indirect(sig, drop_fn, &[ptr]); + } + _ => { + assert!(!matches!(drop_instance.def, InstanceDef::Virtual(_, _))); + + let fn_abi = + RevealAllLayoutCx(fx.tcx).fn_abi_of_instance(drop_instance, ty::List::empty()); + + let arg_value = drop_place.place_ref( + fx, + fx.layout_of(fx.tcx.mk_ref( + fx.tcx.lifetimes.re_erased, + TypeAndMut { ty, mutbl: crate::rustc_hir::Mutability::Mut }, + )), + ); + let arg_value = adjust_arg_for_abi(fx, arg_value, &fn_abi.args[0], true); + + let mut call_args: Vec<Value> = arg_value.into_iter().collect::<Vec<_>>(); + + if drop_instance.def.requires_caller_location(fx.tcx) { + // Pass the caller location for `#[track_caller]`. + let caller_location = fx.get_caller_location(source_info); + call_args.extend( + adjust_arg_for_abi(fx, caller_location, &fn_abi.args[1], false).into_iter(), + ); + } + + let func_ref = fx.get_function_ref(drop_instance); + fx.bcx.ins().call(func_ref, &call_args); + } + } + } +} |