| use rustc_ast::InlineAsmTemplatePiece; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_hir as hir; |
| use rustc_middle::ty::{self, Article, FloatTy, IntTy, Ty, TyCtxt, TypeVisitable, UintTy}; |
| use rustc_session::lint; |
| use rustc_span::{Symbol, DUMMY_SP}; |
| use rustc_target::asm::{InlineAsmReg, InlineAsmRegClass, InlineAsmRegOrRegClass, InlineAsmType}; |
| |
| pub struct InlineAsmCtxt<'a, 'tcx> { |
| tcx: TyCtxt<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| get_operand_ty: Box<dyn Fn(&'tcx hir::Expr<'tcx>) -> Ty<'tcx> + 'a>, |
| } |
| |
| impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> { |
| pub fn new_global_asm(tcx: TyCtxt<'tcx>) -> Self { |
| InlineAsmCtxt { |
| tcx, |
| param_env: ty::ParamEnv::empty(), |
| get_operand_ty: Box::new(|e| bug!("asm operand in global asm: {e:?}")), |
| } |
| } |
| |
| pub fn new_in_fn( |
| tcx: TyCtxt<'tcx>, |
| param_env: ty::ParamEnv<'tcx>, |
| get_operand_ty: impl Fn(&'tcx hir::Expr<'tcx>) -> Ty<'tcx> + 'a, |
| ) -> Self { |
| InlineAsmCtxt { tcx, param_env, get_operand_ty: Box::new(get_operand_ty) } |
| } |
| |
| // FIXME(compiler-errors): This could use `<$ty as Pointee>::Metadata == ()` |
| fn is_thin_ptr_ty(&self, ty: Ty<'tcx>) -> bool { |
| // Type still may have region variables, but `Sized` does not depend |
| // on those, so just erase them before querying. |
| if ty.is_sized(self.tcx, self.param_env) { |
| return true; |
| } |
| if let ty::Foreign(..) = ty.kind() { |
| return true; |
| } |
| false |
| } |
| |
| fn check_asm_operand_type( |
| &self, |
| idx: usize, |
| reg: InlineAsmRegOrRegClass, |
| expr: &'tcx hir::Expr<'tcx>, |
| template: &[InlineAsmTemplatePiece], |
| is_input: bool, |
| tied_input: Option<(&'tcx hir::Expr<'tcx>, Option<InlineAsmType>)>, |
| target_features: &FxHashSet<Symbol>, |
| ) -> Option<InlineAsmType> { |
| let ty = (self.get_operand_ty)(expr); |
| if ty.has_non_region_infer() { |
| bug!("inference variable in asm operand ty: {:?} {:?}", expr, ty); |
| } |
| let asm_ty_isize = match self.tcx.sess.target.pointer_width { |
| 16 => InlineAsmType::I16, |
| 32 => InlineAsmType::I32, |
| 64 => InlineAsmType::I64, |
| _ => unreachable!(), |
| }; |
| |
| let asm_ty = match *ty.kind() { |
| // `!` is allowed for input but not for output (issue #87802) |
| ty::Never if is_input => return None, |
| ty::Error(_) => return None, |
| ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Some(InlineAsmType::I8), |
| ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => Some(InlineAsmType::I16), |
| ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => Some(InlineAsmType::I32), |
| ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => Some(InlineAsmType::I64), |
| ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => Some(InlineAsmType::I128), |
| ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => Some(asm_ty_isize), |
| ty::Float(FloatTy::F32) => Some(InlineAsmType::F32), |
| ty::Float(FloatTy::F64) => Some(InlineAsmType::F64), |
| ty::FnPtr(_) => Some(asm_ty_isize), |
| ty::RawPtr(ty::TypeAndMut { ty, mutbl: _ }) if self.is_thin_ptr_ty(ty) => { |
| Some(asm_ty_isize) |
| } |
| ty::Adt(adt, substs) if adt.repr().simd() => { |
| let fields = &adt.non_enum_variant().fields; |
| let elem_ty = fields[0].ty(self.tcx, substs); |
| match elem_ty.kind() { |
| ty::Never | ty::Error(_) => return None, |
| ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => { |
| Some(InlineAsmType::VecI8(fields.len() as u64)) |
| } |
| ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => { |
| Some(InlineAsmType::VecI16(fields.len() as u64)) |
| } |
| ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => { |
| Some(InlineAsmType::VecI32(fields.len() as u64)) |
| } |
| ty::Int(IntTy::I64) | ty::Uint(UintTy::U64) => { |
| Some(InlineAsmType::VecI64(fields.len() as u64)) |
| } |
| ty::Int(IntTy::I128) | ty::Uint(UintTy::U128) => { |
| Some(InlineAsmType::VecI128(fields.len() as u64)) |
| } |
| ty::Int(IntTy::Isize) | ty::Uint(UintTy::Usize) => { |
| Some(match self.tcx.sess.target.pointer_width { |
| 16 => InlineAsmType::VecI16(fields.len() as u64), |
| 32 => InlineAsmType::VecI32(fields.len() as u64), |
| 64 => InlineAsmType::VecI64(fields.len() as u64), |
| _ => unreachable!(), |
| }) |
| } |
| ty::Float(FloatTy::F32) => Some(InlineAsmType::VecF32(fields.len() as u64)), |
| ty::Float(FloatTy::F64) => Some(InlineAsmType::VecF64(fields.len() as u64)), |
| _ => None, |
| } |
| } |
| ty::Infer(_) => unreachable!(), |
| _ => None, |
| }; |
| let Some(asm_ty) = asm_ty else { |
| let msg = &format!("cannot use value of type `{ty}` for inline assembly"); |
| let mut err = self.tcx.sess.struct_span_err(expr.span, msg); |
| err.note( |
| "only integers, floats, SIMD vectors, pointers and function pointers \ |
| can be used as arguments for inline assembly", |
| ); |
| err.emit(); |
| return None; |
| }; |
| |
| // Check that the type implements Copy. The only case where this can |
| // possibly fail is for SIMD types which don't #[derive(Copy)]. |
| if !ty.is_copy_modulo_regions(self.tcx, self.param_env) { |
| let msg = "arguments for inline assembly must be copyable"; |
| let mut err = self.tcx.sess.struct_span_err(expr.span, msg); |
| err.note(&format!("`{ty}` does not implement the Copy trait")); |
| err.emit(); |
| } |
| |
| // Ideally we wouldn't need to do this, but LLVM's register allocator |
| // really doesn't like it when tied operands have different types. |
| // |
| // This is purely an LLVM limitation, but we have to live with it since |
| // there is no way to hide this with implicit conversions. |
| // |
| // For the purposes of this check we only look at the `InlineAsmType`, |
| // which means that pointers and integers are treated as identical (modulo |
| // size). |
| if let Some((in_expr, Some(in_asm_ty))) = tied_input { |
| if in_asm_ty != asm_ty { |
| let msg = "incompatible types for asm inout argument"; |
| let mut err = self.tcx.sess.struct_span_err(vec![in_expr.span, expr.span], msg); |
| |
| let in_expr_ty = (self.get_operand_ty)(in_expr); |
| err.span_label(in_expr.span, &format!("type `{in_expr_ty}`")); |
| err.span_label(expr.span, &format!("type `{ty}`")); |
| err.note( |
| "asm inout arguments must have the same type, \ |
| unless they are both pointers or integers of the same size", |
| ); |
| err.emit(); |
| } |
| |
| // All of the later checks have already been done on the input, so |
| // let's not emit errors and warnings twice. |
| return Some(asm_ty); |
| } |
| |
| // Check the type against the list of types supported by the selected |
| // register class. |
| let asm_arch = self.tcx.sess.asm_arch.unwrap(); |
| let reg_class = reg.reg_class(); |
| let supported_tys = reg_class.supported_types(asm_arch); |
| let Some((_, feature)) = supported_tys.iter().find(|&&(t, _)| t == asm_ty) else { |
| let msg = &format!("type `{ty}` cannot be used with this register class"); |
| let mut err = self.tcx.sess.struct_span_err(expr.span, msg); |
| let supported_tys: Vec<_> = |
| supported_tys.iter().map(|(t, _)| t.to_string()).collect(); |
| err.note(&format!( |
| "register class `{}` supports these types: {}", |
| reg_class.name(), |
| supported_tys.join(", "), |
| )); |
| if let Some(suggest) = reg_class.suggest_class(asm_arch, asm_ty) { |
| err.help(&format!( |
| "consider using the `{}` register class instead", |
| suggest.name() |
| )); |
| } |
| err.emit(); |
| return Some(asm_ty); |
| }; |
| |
| // Check whether the selected type requires a target feature. Note that |
| // this is different from the feature check we did earlier. While the |
| // previous check checked that this register class is usable at all |
| // with the currently enabled features, some types may only be usable |
| // with a register class when a certain feature is enabled. We check |
| // this here since it depends on the results of typeck. |
| // |
| // Also note that this check isn't run when the operand type is never |
| // (!). In that case we still need the earlier check to verify that the |
| // register class is usable at all. |
| if let Some(feature) = feature { |
| if !target_features.contains(&feature) { |
| let msg = &format!("`{}` target feature is not enabled", feature); |
| let mut err = self.tcx.sess.struct_span_err(expr.span, msg); |
| err.note(&format!( |
| "this is required to use type `{}` with register class `{}`", |
| ty, |
| reg_class.name(), |
| )); |
| err.emit(); |
| return Some(asm_ty); |
| } |
| } |
| |
| // Check whether a modifier is suggested for using this type. |
| if let Some((suggested_modifier, suggested_result)) = |
| reg_class.suggest_modifier(asm_arch, asm_ty) |
| { |
| // Search for any use of this operand without a modifier and emit |
| // the suggestion for them. |
| let mut spans = vec![]; |
| for piece in template { |
| if let &InlineAsmTemplatePiece::Placeholder { operand_idx, modifier, span } = piece |
| { |
| if operand_idx == idx && modifier.is_none() { |
| spans.push(span); |
| } |
| } |
| } |
| if !spans.is_empty() { |
| let (default_modifier, default_result) = |
| reg_class.default_modifier(asm_arch).unwrap(); |
| self.tcx.struct_span_lint_hir( |
| lint::builtin::ASM_SUB_REGISTER, |
| expr.hir_id, |
| spans, |
| "formatting may not be suitable for sub-register argument", |
| |lint| { |
| lint.span_label(expr.span, "for this argument"); |
| lint.help(&format!( |
| "use `{{{idx}:{suggested_modifier}}}` to have the register formatted as `{suggested_result}`", |
| )); |
| lint.help(&format!( |
| "or use `{{{idx}:{default_modifier}}}` to keep the default formatting of `{default_result}`", |
| )); |
| lint |
| }, |
| ); |
| } |
| } |
| |
| Some(asm_ty) |
| } |
| |
| pub fn check_asm(&self, asm: &hir::InlineAsm<'tcx>, enclosing_id: hir::HirId) { |
| let hir = self.tcx.hir(); |
| let enclosing_def_id = hir.local_def_id(enclosing_id).to_def_id(); |
| let target_features = self.tcx.asm_target_features(enclosing_def_id); |
| let Some(asm_arch) = self.tcx.sess.asm_arch else { |
| self.tcx.sess.delay_span_bug(DUMMY_SP, "target architecture does not support asm"); |
| return; |
| }; |
| for (idx, (op, op_sp)) in asm.operands.iter().enumerate() { |
| // Validate register classes against currently enabled target |
| // features. We check that at least one type is available for |
| // the enabled features. |
| // |
| // We ignore target feature requirements for clobbers: if the |
| // feature is disabled then the compiler doesn't care what we |
| // do with the registers. |
| // |
| // Note that this is only possible for explicit register |
| // operands, which cannot be used in the asm string. |
| if let Some(reg) = op.reg() { |
| // Some explicit registers cannot be used depending on the |
| // target. Reject those here. |
| if let InlineAsmRegOrRegClass::Reg(reg) = reg { |
| if let InlineAsmReg::Err = reg { |
| // `validate` will panic on `Err`, as an error must |
| // already have been reported. |
| continue; |
| } |
| if let Err(msg) = reg.validate( |
| asm_arch, |
| self.tcx.sess.relocation_model(), |
| &target_features, |
| &self.tcx.sess.target, |
| op.is_clobber(), |
| ) { |
| let msg = format!("cannot use register `{}`: {}", reg.name(), msg); |
| self.tcx.sess.struct_span_err(*op_sp, &msg).emit(); |
| continue; |
| } |
| } |
| |
| if !op.is_clobber() { |
| let mut missing_required_features = vec![]; |
| let reg_class = reg.reg_class(); |
| if let InlineAsmRegClass::Err = reg_class { |
| continue; |
| } |
| for &(_, feature) in reg_class.supported_types(asm_arch) { |
| match feature { |
| Some(feature) => { |
| if target_features.contains(&feature) { |
| missing_required_features.clear(); |
| break; |
| } else { |
| missing_required_features.push(feature); |
| } |
| } |
| None => { |
| missing_required_features.clear(); |
| break; |
| } |
| } |
| } |
| |
| // We are sorting primitive strs here and can use unstable sort here |
| missing_required_features.sort_unstable(); |
| missing_required_features.dedup(); |
| match &missing_required_features[..] { |
| [] => {} |
| [feature] => { |
| let msg = format!( |
| "register class `{}` requires the `{}` target feature", |
| reg_class.name(), |
| feature |
| ); |
| self.tcx.sess.struct_span_err(*op_sp, &msg).emit(); |
| // register isn't enabled, don't do more checks |
| continue; |
| } |
| features => { |
| let msg = format!( |
| "register class `{}` requires at least one of the following target features: {}", |
| reg_class.name(), |
| features |
| .iter() |
| .map(|f| f.as_str()) |
| .intersperse(", ") |
| .collect::<String>(), |
| ); |
| self.tcx.sess.struct_span_err(*op_sp, &msg).emit(); |
| // register isn't enabled, don't do more checks |
| continue; |
| } |
| } |
| } |
| } |
| |
| match *op { |
| hir::InlineAsmOperand::In { reg, ref expr } => { |
| self.check_asm_operand_type( |
| idx, |
| reg, |
| expr, |
| asm.template, |
| true, |
| None, |
| &target_features, |
| ); |
| } |
| hir::InlineAsmOperand::Out { reg, late: _, ref expr } => { |
| if let Some(expr) = expr { |
| self.check_asm_operand_type( |
| idx, |
| reg, |
| expr, |
| asm.template, |
| false, |
| None, |
| &target_features, |
| ); |
| } |
| } |
| hir::InlineAsmOperand::InOut { reg, late: _, ref expr } => { |
| self.check_asm_operand_type( |
| idx, |
| reg, |
| expr, |
| asm.template, |
| false, |
| None, |
| &target_features, |
| ); |
| } |
| hir::InlineAsmOperand::SplitInOut { reg, late: _, ref in_expr, ref out_expr } => { |
| let in_ty = self.check_asm_operand_type( |
| idx, |
| reg, |
| in_expr, |
| asm.template, |
| true, |
| None, |
| &target_features, |
| ); |
| if let Some(out_expr) = out_expr { |
| self.check_asm_operand_type( |
| idx, |
| reg, |
| out_expr, |
| asm.template, |
| false, |
| Some((in_expr, in_ty)), |
| &target_features, |
| ); |
| } |
| } |
| // No special checking is needed for these: |
| // - Typeck has checked that Const operands are integers. |
| // - AST lowering guarantees that SymStatic points to a static. |
| hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::SymStatic { .. } => {} |
| // Check that sym actually points to a function. Later passes |
| // depend on this. |
| hir::InlineAsmOperand::SymFn { anon_const } => { |
| let ty = self.tcx.typeck_body(anon_const.body).node_type(anon_const.hir_id); |
| match ty.kind() { |
| ty::Never | ty::Error(_) => {} |
| ty::FnDef(..) => {} |
| _ => { |
| let mut err = |
| self.tcx.sess.struct_span_err(*op_sp, "invalid `sym` operand"); |
| err.span_label( |
| self.tcx.hir().span(anon_const.body.hir_id), |
| &format!("is {} `{}`", ty.kind().article(), ty), |
| ); |
| err.help("`sym` operands must refer to either a function or a static"); |
| err.emit(); |
| } |
| }; |
| } |
| } |
| } |
| } |
| } |
