--- /dev/null
+use rustc_ast::InlineAsmTemplatePiece;
+use rustc_data_structures::stable_set::FxHashSet;
+use rustc_errors::struct_span_err;
+use rustc_hir as hir;
+use rustc_index::vec::Idx;
+use rustc_middle::ty::layout::{LayoutError, SizeSkeleton};
+use rustc_middle::ty::{self, Article, FloatTy, IntTy, Ty, TyCtxt, TypeFoldable, UintTy};
+use rustc_session::lint;
+use rustc_span::{Span, Symbol, DUMMY_SP};
+use rustc_target::abi::{Pointer, VariantIdx};
+use rustc_target::asm::{InlineAsmReg, InlineAsmRegClass, InlineAsmRegOrRegClass, InlineAsmType};
+use rustc_trait_selection::infer::InferCtxtExt;
+
+use super::FnCtxt;
+
+/// If the type is `Option<T>`, it will return `T`, otherwise
+/// the type itself. Works on most `Option`-like types.
+fn unpack_option_like<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
+ let ty::Adt(def, substs) = *ty.kind() else { return ty };
+
+ if def.variants().len() == 2 && !def.repr().c() && def.repr().int.is_none() {
+ let data_idx;
+
+ let one = VariantIdx::new(1);
+ let zero = VariantIdx::new(0);
+
+ if def.variant(zero).fields.is_empty() {
+ data_idx = one;
+ } else if def.variant(one).fields.is_empty() {
+ data_idx = zero;
+ } else {
+ return ty;
+ }
+
+ if def.variant(data_idx).fields.len() == 1 {
+ return def.variant(data_idx).fields[0].ty(tcx, substs);
+ }
+ }
+
+ ty
+}
+
+impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
+ pub fn check_transmute(&self, span: Span, from: Ty<'tcx>, to: Ty<'tcx>) {
+ let convert = |ty: Ty<'tcx>| {
+ let ty = self.resolve_vars_if_possible(ty);
+ let ty = self.tcx.normalize_erasing_regions(self.param_env, ty);
+ (SizeSkeleton::compute(ty, self.tcx, self.param_env), ty)
+ };
+ let (sk_from, from) = convert(from);
+ let (sk_to, to) = convert(to);
+
+ // Check for same size using the skeletons.
+ if let (Ok(sk_from), Ok(sk_to)) = (sk_from, sk_to) {
+ if sk_from.same_size(sk_to) {
+ return;
+ }
+
+ // Special-case transmuting from `typeof(function)` and
+ // `Option<typeof(function)>` to present a clearer error.
+ let from = unpack_option_like(self.tcx, from);
+ if let (&ty::FnDef(..), SizeSkeleton::Known(size_to)) = (from.kind(), sk_to) && size_to == Pointer.size(&self.tcx) {
+ struct_span_err!(self.tcx.sess, span, E0591, "can't transmute zero-sized type")
+ .note(&format!("source type: {from}"))
+ .note(&format!("target type: {to}"))
+ .help("cast with `as` to a pointer instead")
+ .emit();
+ return;
+ }
+ }
+
+ // Try to display a sensible error with as much information as possible.
+ let skeleton_string = |ty: Ty<'tcx>, sk| match sk {
+ Ok(SizeSkeleton::Known(size)) => format!("{} bits", size.bits()),
+ Ok(SizeSkeleton::Pointer { tail, .. }) => format!("pointer to `{tail}`"),
+ Err(LayoutError::Unknown(bad)) => {
+ if bad == ty {
+ "this type does not have a fixed size".to_owned()
+ } else {
+ format!("size can vary because of {bad}")
+ }
+ }
+ Err(err) => err.to_string(),
+ };
+
+ let mut err = struct_span_err!(
+ self.tcx.sess,
+ span,
+ E0512,
+ "cannot transmute between types of different sizes, \
+ or dependently-sized types"
+ );
+ if from == to {
+ err.note(&format!("`{from}` does not have a fixed size"));
+ } else {
+ err.note(&format!("source type: `{}` ({})", from, skeleton_string(from, sk_from)))
+ .note(&format!("target type: `{}` ({})", to, skeleton_string(to, sk_to)));
+ }
+ err.emit();
+ }
+
+ // 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 self.tcx.erase_regions(ty).is_sized(self.tcx.at(DUMMY_SP), 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: &hir::Expr<'tcx>,
+ template: &[InlineAsmTemplatePiece],
+ is_input: bool,
+ tied_input: Option<(&hir::Expr<'tcx>, Option<InlineAsmType>)>,
+ target_features: &FxHashSet<Symbol>,
+ ) -> Option<InlineAsmType> {
+ // Check the type against the allowed types for inline asm.
+ let ty = self.typeck_results.borrow().expr_ty_adjusted(expr);
+ let ty = self.resolve_vars_if_possible(ty);
+ let asm_ty_isize = match self.tcx.sess.target.pointer_width {
+ 16 => InlineAsmType::I16,
+ 32 => InlineAsmType::I32,
+ 64 => InlineAsmType::I64,
+ _ => unreachable!(),
+ };
+
+ // Expect types to be fully resolved, no const or type variables.
+ if ty.has_infer_types_or_consts() {
+ assert!(self.is_tainted_by_errors());
+ return None;
+ }
+
+ 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 !self.infcx.type_is_copy_modulo_regions(self.param_env, ty, DUMMY_SP) {
+ 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.typeck_results.borrow().expr_ty_adjusted(in_expr);
+ let in_expr_ty = self.resolve_vars_if_possible(in_expr_ty);
+ 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,
+ |lint| {
+ let msg = "formatting may not be suitable for sub-register argument";
+ let mut err = lint.build(msg);
+ err.span_label(expr.span, "for this argument");
+ err.help(&format!(
+ "use the `{suggested_modifier}` modifier to have the register formatted as `{suggested_result}`",
+ ));
+ err.help(&format!(
+ "or use the `{default_modifier}` modifier to keep the default formatting of `{default_result}`",
+ ));
+ err.emit();
+ },
+ );
+ }
+ }
+
+ 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();
+ }
+ };
+ }
+ }
+ }
+ }
+}
projects / rustc.git / blobdiff